[0001] This invention is concerned with improvements in or relating to folding machines,
comprising a main drive shaft driven by a motor, folding instrumentalities arranged
at an operating locality of the machine, workpiece feeding means operable in timed
relation with the rotation of the main drive shaft for feeding a workpiece to be folded
through the operating locality, and operator-controlled feed speed variation means
for varying the speed of rotation of the main drive shaft.
[0002] One such machine is described in EP-A-0 110 591 wherein the motor by which the main
drive shaft is driven incorporates an integral clutch-and-brake arrangement together
with an electronic control, whereby the output speed of the motor can be accurately
controlled, and the operation of the motor is under the control of the operator via
a foot treadle connected to the motor, and more specifically to the electronic control
arrangement thereof, by a mechanical linkage. Apart from the fact that such a motor
arrangement is relatively expensive, in addition the degree of control of the speed
of rotation of the main drive shaft is not especially high, in so far such control
relies solely upon the manipulation of the foot treadle. For example, in the case
of an inexperienced operator wishing to operate the machine at less than full speed,
such an operator has to control the reduced speed range using only that amount of
travel of the foot treadle to which the desired speed range relates, so that in effect
the control of the rotational speed becomes more coarse over the reduced speed range
than is the case where the more experienced operator is using the full speed range.
Clearly, therefore, the speed control arrangement in this case acts against the inexperienced
operator when it would be preferable for the speed control arrangement to accommodate
the learning cycle. Again, in other circumstances it may be desirable to operate the
machine at a constant feed in circumstances where, because of the size of the workpiece,
the operator is unable to actuate the foot treadle, but clearly the feed speed (and
thus the rotational speed of the main drive shaft) will have to be set appropriate
to the workpiece and will certainly not always be the maximum feed speed of the machine.
To cater for such circumstances, therefore, a higher degree of control of the rotational
speed of the main drive shaft is again desirable.
[0003] It is thus the object of the invention to provide an improved folding machine in
which a higher degree of control of the speed of rotation of the main drive shaft
is achieved without additional expenditure on the speed control arrangement, but preferable
rather with a cost reduction in this regard.
[0004] This object is resolved in accordance with the present invention, in a machine as
set out in the first paragraph above, in that the motor for the main drive shaft is
an a.c. induction motor provided with an inverter, and in that the feed speed variation
means comprises a transducer providing an analogue output which is variable according
to the setting of the transducer under operator control, the machine being further
characterised by an analogue-to-digital converter which receives the analogue output
of the transducer and converts it to a digital value which is thus variable in accordance
with the setting of the transducer, computer control means for receiving the digital
value and for modifying it in accordance with one or more inputs each in the form
of a signal having a value determined according to an operational setting of the folding
machine, and a digital-to-analogue converter for converting the digital value, thus
modified, to an analogue drive signal which is supplied to the inverter, such that
the speed of rotation of the a.c. motor, and thus of the main drive shaft, is determined
in accordance with the setting of the transducer, but modified in accordance with
one or more of said inputs.
[0005] It will thus be appreciated that in the machine in accordance with the invention
the speed of rotation of the main drive shaft is now controlled by the computer control
means, thereby providing the facility not only for greater speed control, as will
be discussed in greater detail hereinafter, but also enabling the speed control arrangement
to be integrated into the main control system of the machine. At the same time, by
replacing the clutch-and-brake arrangement of the earlier machine with a simple transducer,
which can of course be incorporated within the foot treadle, a simpler and less expensive
operator-actuatable control is achieved.
[0006] In one embodiment of the present invention, the machine comprises conventional workpiece
feeding means, viz. an orbitally movable hammer-and-anvil arrangement driven by the
main drive shaft. In such embodiment, advantageously the output of the transducer
may be dedicated over different sections of its range to different functions. Thus
the output may correspond, according to its value, to a "stop" condition, a "drive"
condition or a condition in which the operation of the machine is stopped with the
hammer-and-anvil in a closed condition. To this end the treadle or like control may
be biassed away from one end of the traverse of the transducer into its "stop" condition,
so that it can be moved in one direction of traverse to its "drive" condition or in
an opposite direction to said further condition. It will of course be appreciated
that in the "drive" condition the output will be variable over a relatively wide range
to provide the workpiece feed speed variation function of the treadle.
[0007] One advantage of utilising the computer control means to control the speed of rotation
of the main drive shaft is that the possibility of a feedback arises and preferably
in accordance with the invention monitoring means is provided whereby the speed of
rotation of the main drive shaft is monitored, and more particularly the drive signal
supplied to the inverter from the computer control means is modified by an input from
the monitoring means if and to the extent that the actual speed of rotation as monitored
does not match the notional speed which corresponds to the particular setting of the
transducer, such modification being such as to effect matching of said actual speed
with said notional speed.
[0008] For facilitating control of the workpiece feed, furthermore, speed range variation
means may also be provided which provides an input to the computer control means whereby
the speed range, within which the speed of rotation of the main drive shaft can be
varied under the control of the operator as aforesaid, can be varied, the variation
being proportional in respect of any setting of the feed speed variation means such
that for a given such setting the speed of rotation of the main drive shaft will vary
in accordance with the proportion set by the speed range variation means. Such a machine,
it will be appreciated, thus enables not only the maximum operation speed of the machine
to be pre-set, which can in itself be advantageous, but further, by proportionally
varying all the speeds within the selected speed range, enables the selected speed
range to be controlled in response to the whole of the allowed travel of the feed
speed variation means, so that the degree of control afforded by the foot treadle
or the like is not rendered coarser by reason of a reduction in the maximum operational
speed.
[0009] In the machine in accordance with the invention, furthermore, conveniently feed length
variation means is provided for varying the distance through which a workpiece is
fed by the workpiece feeding means for each rotation of the main drive shaft. In said
machine the feed length variation means comprises an n.c. motor operation of which
is effective, in response to control signals supplied by the computer control means,
to displace a feed length control lever whereby to cause the feed length to be varied,
and the computer control means calculates the rate at which a feed length variation
is to take place based upon the required displacement of said lever to achieve a desired
feed length variation and also the speed of rotation of the main drive shaft.
[0010] It will of course be appreciated that the invention is also applicable to so-called
thermo-cementing and folding machines, more particularly of the aforementioned type
comprising also adhesive supply means, including a gear pump driven by an n.c. motor,
for supplying adhesive to portions of a workpiece to be folded as it is fed through
the operating locality of the machine by the workpiece feeding means, the computer
control means also supplying to said n.c. motor a drive signal the value of which
is dependent upon the speed of rotation of the main drive shaft and operational state
of the feed speed variation means. In the machine in accordance with the invention,
furthermore, preferably said drive signal, and thus the rate of adhesive supply, is
dependent upon the value of the digital signal supplied to the computer control means,
but modified as aforementioned. In this way, therefore, the drive signal to the n.c.
motor can be varied not only according to the feed speed, as detected by the monitoring
of the main drive shaft rotation, but also proportionally with the value of the signal
applied by the adhesive supply rate setting means, so that an even deposition of adhesive
can be achieved regardless of the feed speed and the rate of adhesive supply required.
In the machine in accordance with the invention, furthermore, operator-actuatable
means may be provided which provides an input to the computer control means and by
which a plurality of pre-settings can be made for the workpiece feed length for selection
according to the contour of the workpiece edge to be folded, the arrangement being
such that the feed length variation means is effective to set the feed length in accordance
with a selected one of such settings upon receipt of an appropriate signal from the
computer control means. In practice, preferably the "standard" pre-set feed length
is the feed length which is used when a straight portion (i.e. a portion without significant
edge curvature) of the workpiece is being processed, while the other pre-set feed
lengths are introduced when portions of significant curvature, usually referred to
as "outside" or inside" corners of the workpiece, are being treated. By an "ouside"
corner, where referred to herein, is to be understood an edge portion having a curvature
the centre of which lies within the body of the workpiece, and an "insider" corner
refers to an edge portion of curvature the centre of which lies outside the main body
of the workpiece. (It will be appreciated that in folding an outside corner in general
an amount of material is folded over which is in excess of the material onto which
it is being folded so that it is necessary to "pleat" the folded edge, while in the
case of an inside corner less material is being folded over and it is necessary often
to "snip" the folded edge in order to distribute it evenly.
[0011] As in the machine disclosed in EP-A 0110591 preferably the workpiece detecting devices
are disposed at or adjacent the operating locality of the machine and comprise a "workpiece
present" detecting device, which serve to detect the presence of a workpiece, and
also a "corner" detecting device which serves to detect the approach of both "outside"
and "inside" corners (as hereinbefore defined) to the operating locality as the workpiece
is being fed therethrough. In the operation of the machine detection of an approaching
corner thus serves to cause an appropriate one of the pre-set feed lengths to be selected
while the "workpiece present" detecting device causes the supply of adhesive to be
initiated when the presence of a workpiece is detected thereby. Moreover, in the machine
in accordance with the invention conveniently operator-actuatable means is provided
by which an input is provided to the computer control means whereby the feed speed
variation means is disabled and the "workpiece present" detecting device is enabled
to initiate also operation of the workpiece feeding means when the presence of a workpiece
is detected thereby, the speed of rotation of the main drive shaft being set at the
maximum within the selectively set speed range and the various pre-set feed lengths
being selected according to the contour of the workpiece edge as detected by the "corner"
detecting device. In this way, it will be appreciated, the operator can control the
operation of the machine without accessing the transducer, it being of course desirable
that the maximum feed speed as set is appropriate to the edge contour of the workpiece
being operated upon.
[0012] It will thus be appreciated that, in using the machine in accordance with the invention,
a greater degree of control over not only the feed speed (or speed of rotation of
the main drive shaft) is obtained but also a greater control over the adhesive supply
and other operating functions of the machine.
[0013] There now follows a detailed description to be read with reference to the accompanying
drawings, of one machine in accordance with the invention, which machine has been
selected for description merely by way of exemplification of the invention and not
by way of limitation thereof.
[0014] In the accompanying drawings:-
Figure 1 is a front view of the machine in accordance with the invention;
Figure 2 is a block diagram of an electronic control circuit of said machine;
Figures 3A and 3B constitute a flow chart relating to the control of the general operation
of the machine;
Figures 4A and 4B constitute a flow chart indicating the control of the speed of rotation
of a main drive shaft of the machine;
Figure 5 is a flow chart indicating the control of the rate of adhesive supply; and
Figure 6 is a flow chart indicating the manner in which a feed length adjustment takes
place.
[0015] The machine in accordance with the invention now to be described is a so-called thermo-cementing
and folding machine, which finds use in the shoe industry and allied trades and is
generally similar, except as hereinafter described, to the machine described in GB-A
2141968, itself a modification of the machine described in EP-A 0110591. The machine
thus comprises a work table 10 on which a workpiece can be supported at an operating
locality of the machine, at which conventional folding instrumentalities are located,
comprising a fold-initiating block 12 having an upwardly curved work-guiding surface
14, a gauge finger 16, a creaser foot 22 and a lip turner (not shown), which completes
the fold of the workpiece edge over the creaser foot. During folding, adhesive can
be applied to the workpiece edge through an outlet in the creaser foot, to which adhesive
is supplied via a delivery tube 24 from a melt chamber 28 under the action of a gear
pump 26. The melt chamber 28, delivery tube 24 and creaser foot 22 are heated respectively
by heaters H1, H2, H3. Other features of the folding instrumentalities are shown in
Figure 1.
[0016] "Downstream" of the folding instrumentalities are located conventional edge snipping
means generally designated 30, comprising a fixed and movable blade 32, 34, and conventional
workpiece feeding means in the form of an orbitally moving hammer-and-anvil arrangement
(not shown), which also serves to consolidate the fold. A work release clamp (not
shown) is also provided for clamping the work against the under-side of the creaser
foot during the return movement of the hammer-and-anvil arrangement.
[0017] The hammer-and-anvil arrangement is driven through a main drive shaft (not shown)
by means of an electric motor M1 operation of which is controlled in turn by computer
control means (see Figures 2 to 6) through an inverter I. The inverter receives drive
signals from the computer control means in the form of a voltage, and supplies corresponding
control signals, also in the form of a voltage,to the electric motor. The electric
motor is in this case an a.c. induction motor. As will be hereinafter described in
detail, the motor and more particularly the speed of the motor, and thus the speed
of rotation of the main drive shaft (hereinafter referred to as the "feed speed")
may be controlled either automatically or by the operator using a first treadle (not
shown), which incorporates a transducer T (Figure 2). In addition, a second treadle
(also not shown) is provided by means of which, by selectively depressing respectively
the toeward and heelward portions thereof, two switches S6, S7 can be actuated under
operator control. Again as will be described in detail hereinafter, switch S6 actuates
a stepping motor SM1 by which, through a mechanical arrangement including a feed length
control lever (not shown), the amount through which the hammer-and-anvil arrangement
moves fore-and-aft for each revolution of the main drive shaft (hereinafter referred
to as the "feed length") is varied thus to effect pleating of the folded over margin
of the workpiece. Similarly switch S7 operates a solenoid SOL2 which causes the edge
snipping means 30 to operate and at the same time operates the motor SM1 to vary the
feed length according to the appropriate setting.
[0018] For determining the feed length provision is made in the form of three selector devices
SS1, SS2, SS3 on a control panel 36 of the machine. Each selector device comprises
a digital display and means for scrolling up or down the displayed numerical indicator;
each selector or device is thus capable of selecting a feed length in a range 0 to
9. The first selector device SS1 is utilised to set the feed length for "normal" operation,
the second SS2 for a snipping operation (which will normally occur when an "inside"
corner is passing through the operating locality), and the third SS3 for a pleating
operation (which will usually occur when an "outside" corner is passing through the
operating locality). It is to be understood that in general, as is common in folding
machines, the pleating feed length is likely to be relatively short, in order to enable
pleating to be effected, while the "snipping" feed length will normally be somewhat
longer, in order to avoid mere fraying of the edge by too many snips being made in
the fold.
[0019] The feed length can be set up for each operation of the machine, but a further selector
device SS4 is also provided on the control panel. This further device incorporates
a twin digital display and serves to enable a double-digit style number to be allocated
to each combination of feed lengths selected, the style number providing access, via
the computer control means, to a memory in which information relating to the feed
lengths is stored at an address accessed by the style number.
[0020] The machine has a "mains on/off" switch S1, a "motor on/off" S2, a "work lamp on/off"
switch S3 and so-called knee-switch S5 for purposes which will be described later.
[0021] The control panel 36 of the machine also has the following switches for the purposes
set out hereinafter:
Switch S4, which is an "adhesive supply on/off switch incorporating a first pilot
light, indicating "on", a second pilot light which, as the adhesive is heating, flashes
to indicate adhesive is not available for supply, but which, when the temperature
of the adhesive has been reached, is continuously illuminated to indicate that the
adhesive supply is available, and a third light which indicates that the adhesive
is in fact being supplied:
Switch S8, by which the second treadle is enabled/disabled:
Switch S9, by which selectively snipping, pleating and adhesive on/off functions
can be effected automatically or under operator control, pilot lights being provided
for indicating which mode has been selected:
Switch S10, which is a three-position pre-selector switch by which the operator
can selectively utilise the knee-switch S5 when the machine is operating in its "automatic"
operating mode (as selected by switch S9). More specifically, switch S10 can be switched
between "off", in which the knee-switch S5 is not effective, an "adhesive inhibit"
position, in which, when the knee-switch S5 is held operated, the supply of adhesive
to the creaser foot 22 is inhibited, and a "snip inhibit" position, in which the edge
snipping means is disabled while the knee-switch S5 is held operated;
Switch S11, by which the control of the motor is selectively achieved automatically
or under operator control, pilot lamps being provided for indicating which selection
has been made; and
Switch S12, by which the selection of a "pleating" feed length can be prevented.
[0022] Also on the control panel 36 are further selector devices, each of which comprises
a plurality of bars which can be illuminated to indicate a progressive incrementing
or decrementing of a value, selector buttons (+ and -) being provided for effecting
such incrementing and decrementing:
Device SS5, by which the supply of adhesive at the start of a cycle of operation
of the machine may be delayed;
Device SS6, by which, the density of "snipping" can be selected by the operator,
generally in the manner set out in GB-A 2148541;
Device SS7, by which, as will be described in detail hereinafter, the range of
speeds over which the machine will operate up to a pre-set maximum can be selected;
Device SS8, by which the temperature of the creaser foot 22 can be varied; and
Device SS9 serves to control the operating speed of the stepping motor SM2 by which
the rate of adhesive supply can be controlled as will be described hereinafter.
[0023] When the machine is in an automatic mode of operation (selected by switch S9), the
control of adhesive supply (on/off function) and the selection of feed length is effected
using a sensing arrangement including two emitters E1, E2 (constituting first sensing
means of the machine) by which the supply of adhesive is controlled, four emitters
E3, E4, E5, E6 (constituting third sensing means of the machine) by which an approaching
"inside" corner in the edge contour of the workpiece being operated upon is sensed
and which control solenoid SOL2 and also serve to select the "snipping" feed length,
and a further emitter E7 (constituting second sensing means of the machine) by which
an approaching "outside" corner in the workpiece edge contour is sensed and the "pleating"
feed length selected.
[0024] In the machine in accordance with the invention, when switch S1 is switched on, mains
power is supplied sequentially to heaters H1, H2 and H3 such that the various integers
heated thereby reach operating temperature at essentially the same time. When the
temperature of each integer is reached, then, assuming that switch S4 is switch "on",
the appropriate lamp indicates that adhesive is available and that the machine is
ready for operation. At the same time, power is supplied to solenoid SOL2, which,
in response to appropriate signals, controls the edge snipping arrangement 30, and
also to a transformer (not shown) which steps down the voltage to 12 volts for supply
to a work lamp circuit which includes the "worklamp" switch S3. The 12 volt circuit
is an a.c. supply, but from this is derived an unsmoothed 12 volts d.c. circuit which
supplies power to a mains-controlled control box CB supplying a "mains interrupt"
signal, to be referred to hereinafter. In addition, there is derived from the 12 volt
a.c. circuit a smoothed 12 volt d.c. circuit which supplies power to stepper motor
SM2, which drives the gear pump and also to stepper motor SM1, by which a feed length
control lever is operated; this lever is displaceable under the action of the stepper
motor, such displacement causing the feed length to be varied. (This arrangement is
well known in folding machines.) From the smoothed 12 volt d.c. circuit, furthermore,
is derived a 5 volts circuit, which drives a central processor unit CPU and associated
circuits and also provides power to the various switches and integers of the electrical
and electronic circuits of the machine.
[0025] The central processor unit CPU, which controls the machine, is constituted by a single-chip
8-bit micro-computer (in casu, a Zilog Z8681 which, in addition to a micro-processor,
also incorporates a random access memory/scratch pad RAM (shown separately in Figure
2); this micro-processor is obtainable from Zilog Inc). For the internal timing of
the CPU a system clock C, comprising a free-running 12 MHz crystal, is provided. The
CPU is connected via input-output bus I/OB with input and output ports IP, OP, a non-volatile
memory in the form of an EPROM (erasable programmable read-only memory), which is
accessed by the CPU via the I/OB for instructions to execute, and an EEPROM (electrically
erasable programmable read-only memory) for the storage of style and "machine status"
information. In addition, an analogue-to-digital converter ADC is provided, to which
analogue signals are supplied by the various integers shown in Figure 2, including
the transducer T and thermisters TS1, TS2, TS3 (which sense the temperatures of the
components heated by heaters H1, H2, H3). The ADC is interrogated by the CPU, via
the data bus I/OB, each time a mains interrupt signal is supplied to the CPU by the
control box CB. More particularly the various channels of the ADC are interrogated
in turn, one in response to each mains interrupt in a so-called "wrap around" sequence.
The ADC supplies information as to the state of the interrogated channel via the input
port IP. The various switches and selector devices supply information as to the state
of the interrogated channel via the data bus I/OB. In addition a digital-to-analogue
converter DAC is provided which supplies analogue control signals to the inverter
I for driving the motor M1, in accordance with digital signals received from the CPU.
The control circuit also comprises a re-set sub-circuit R which is directly connected
into the CPU and by which, upon starting up of the machine, the CPU is enabled to
set the controls to their correct state in a rapid manner. A shaft encoder E driven
by the main drive shaft is also provided having a direct "interrupt" input to the
CPU.
[0026] In response to the various signals thus supplied to the CPU, the CPU supplies outputs
OP via the data bus I/OB to sub-circuits controlling the heaters H1, H2, H3, the solenoid
SOL2, drives for stepper motors SM1, SM2 emitters E1 to E7 and relay RL1, as well
as to the inverter I as already referred to. The relay RL1 serves as a "watch dog"
over the whole of the control circuit. To this end, it is maintained in a "made" condition
during normal operation of the machine by a control sub-circuit which is "refreshed"
at regular intervals, failure to refresh the sub-circuit causing the relay RL1 to
drop out. More particularly, the sub-circuit receives a signal at each mains interrupt,
the signal serving to change the state of the circuit between "1" and "0", the arrangement
being such that switching to the "1" state constituting the "refresh" signal. The
sub-circuit is arranged to become de-energised, in the absence of a refresh signal,
after a time interval which is greater than the interval between two "1" signals.
De-energisation of the sub-circuit of course switches off the relay, thereby terminating
the power supply to the machine.
[0027] In the machine in accordance with the invention the emitters E1 to E7, constituting
the various sensing means, are actuated in response to control pulses supplied by
the CPU sequentially thereto at each system clock interrupt and emit pulses of infra-red
radiation, which are separately received by the receiver E/R located in the machine
head above the emitters. In other machines in accordance with the invention other
types of sensing means may of course be utilised.
[0028] Figures 3 to 6 constitute flow charts indicating various functions of the software
by which the machine in accordance with the invention is controlled. It will be noted
that there are no inscriptions within any of the boxes of the flow charts, but rather
a full description of each step is appended to this specification.
[0029] Referring now to Figures 3A and 3B which relate to the general running of the machine,
at the first step 650 the status of switch S9 is checked to determine whether the
adhesive supply (on/off), snipping and pleating functions are to be controlled automatically,
namely through the emitters E1 to E7, or under operator control, using the knee-switch
S5 and treadles; the machine in this regard operates in the same manner as described
in GB-A 2141968. If a "No" is obtained, indicating that "manual" has been selected,at
step 652 a command is issued to ensure that the motor will not operate in "automatic"
mode, and at step 654 the status of knee-switch S5 is monitored. If the machine is
not switched on, then the software loops back to step 650, but in the event that the
knee-switch is actuated, adhesive is supplied, initially, i.e. at the start of a cycle
of operation of the machine, with a "fast forward" operation of the motor to give
a surge, generally as described in EP-A 0110591 (step 656). The control of the rate
of adhesive supply will be described hereinafter in connection with Figure 5. The
status of knee switch S5 continues to be monitored at step 658; it will be recalled
that as described in GB-A 2141968, the knee switch must be released by the operator
and re-actuated in order to switch off the adhesive flow. When such flow is switched
off, the operation of the stepping motor SM2 is stopped and reversed to provide for
suck-back of the adhesive, both initially and thereafter intermittently, as described
in detail in EP-A 0154441 (step 660).
[0030] It is also to be noted that throughout the operation as set out above, the various
switches and selector devices, e.g. those relating to the control of the snipping
and pleating functions are regularly and frequently monitored and any signals therefrom
processed.
[0031] In the event that "automatic" operation is selected at step 650, then the status
of emitters E1, E2 is interrogated (step 662). In the event that the emitters are
uncovered, then a command is issued to ensure that the motor will not operate in "automatic"
mode (step 664) and the circuit loops back to step 650. Where the emitters E1, E2
are covered, indicating that a workpiece is present then any delay in the initiation
of adhesive supply, as selected by selector device SS5 is executed (step 666) and
thereafter the status of switch S11 is interrogated, to determine whether the motor
M1 is to be controlled automatically or by the operator using the right hand treadle.
In the case of "automatic" selection, the motor M1 is switched on (step 670). If the
"manual" operation is selected, on the other hand, then a signal is awaited from transducer
T associated with the right hand treadle; this will be described in greater detail
with reference to Fig. 4A and 4B. At step 674 the supply of adhesive is initiated,
in the same manner as described previously with reference to step 656 and this continues
until the emitters E1, E2 are once more uncovered (step 674). Upon the uncovering
of the emitters, indicating that a workpiece is no longer present, a delay in switching
off the adhesive supply is calculated (step 676), on the basis of rotations of the
main drive shaft between the uncovering of the first emitter and that of the second;
it will be appreciated that the two emitters lie one after the other in the general
feed direction. The calculated delay is then implemented at step 678 and thereafter
the adhesive supply is switched off (step 680), in the same manner as described with
reference to step 660.
[0032] At step 682 the status of switch S11 is once more interrogated, essentially to ensure
that the workpiece is fed completely out of the operating locality, the arrangement
being such that if "automatic" operation has been selected, a delay, based upon the
current feed length selected by one of selected devices SS1, SS2, SS3, is calculated
and implemented (684 and 686) prior to the motor M1 being switched off (step 688).
In the event that "manual" operation has been selected, then it is assumed that the
operator will ensure that the workpiece has been fed from the operation locality.
Thereafter the circuit loops back to step 650.
[0033] As described in detail in GB-A 2141968, when "automatic" is selected at step 650,
then in the event that switch S10 is appropriately set, the knee-switch may serve
to inhibit either "snipping" or the adhesive supply when actuated. On the other hand,
when "automatic" operation is selected by means of switch S11, operation of the knee-switch
S5 acts as an emergency stop.
[0034] Referring now to Figures 4A and 4B, which relate to the control of the motor M1 and
more particularly to the operation of the machine depending upon the selection made
by switch S11, at step 700 the status of said switch is interrogated. If "automatic"
operation is selected then at step 702 the status of the emitters E1, E2 is interrogated,
that is to say the presence of a workpiece is checked for. If a workpiece is present
then at step 704 the "basic speed" of the motor is set at 2,400 rpm; this is in fact
a function of the software itself, the particular speed being assessed as being the
optimum for the operation of a machine of this kind. At step 706 thereafter the status
of selector device SS7, by which a proportional value of the set speed (in this case
2,400 rpm) is selected by the application of a reduction factor and at step 708 the
software then calculates, e.g. by look-up tables, the value of the drive signal to
be supplied to the motor M1 to achieve the desired speed and the drive signal is supplied
accordingly. At step 710 the actual speed of rotation of the main drive shaft, which
is monitored by the shaft encoder E, is calculated from the output of the encoder
and at step 712 the difference between the calculated and the actual speed is determined
and compared with a pre-set tolerance. If the difference does not lie within the given
tolerance, then the drive signal supplied to the motor M1, as previously calculated
at step 708, is modified according to a feedback factor (step 714), said factor being
calculated so as to bring actual speed of rotation of the shaft up to the desired
speed and this feedback factor is then applied to the drive signal value (step 716).
The feedback factor is thereafter stored and is applied, without further modification,
provided that the difference between the desired and actual speed of rotation of the
main drive shaft remains within the tolerance. The appropriate drive signal is thus
applied to motor M1 (step 718) and the circuit then loops once more back to step 700.
[0035] In the event that at step 702 the emitters E1, E2 become uncovered, indicating that
a workpiece is no longer present, then, bearing in mind that this circuit is continuously
looping, at step 720 a signal to stop the operation of motor M1 is supplied.
[0036] In the case where at step 700 a "manual" operation has been selected, then at step
722 the status of the signal from the transducer associated with the right hand treadle
is interrogated, in particular, the treadle will either indicate a "stop" condition
or a "drive" condition, in which latter case the value of the signal from the transducer
will be converted proportionally to a motor speed. The transducer is also able to
provide a further signal, namely by the operator depressing the treadle with her heel
to signal a requirement that the machine is brought to a stop with the hammer-and-anvil
arrangement in a closed condition; this may be desirable where a workpiece has not
been completely processed but rather it is desirable to carry out some intermediate
operation on the workpiece part-way through a cycle of operation. At step 724, therefore,
this condition of the transducer is sought and in the event that a corresponding signal
is provided, then at step 726 the motor M1 is switched off with the hammer-and-anvil
arrangement in closed condition. Otherwise if no such signal has been provided, then
at step 728 the status of the transducer is interrogated as to whether it is in a
"stop" or "drive" condition. If "stop" has been selected, then the circuit leads to
step 720 and the motor M1 is switched off, this time with the hammer-and-anvil arrangement
in an open condition. In the event that "drive" has been selected, then steps 706
and subsequent steps are followed as described above; that is to say the reduction
factor which is set by device SS7 is applied to the motor speed set according to the
position of the transducer in "drive" mode and drive signals are supplied to the motor
M1 as aforesaid.
[0037] Figure 5 relates to the operation of the adhesive supply means, more particularly
the signalling supplied to stepping motor SM2. Thus, at step 730 the required adhesive
supply rate is checked for, as set by selector device SS9 and, in accordance with
the current speed of rotation of the main drive shaft, as checked from the shaft encoder
(step 732), the requested adhesive supply rate is modified proportionally, namely
by dividing the actual speed of rotation of the main drive shaft by 2,400 and thus
arriving at a proportion to be applied to the requested adhesive rate (step 734).
At step 736 and 738 the question of whether a snipping or pleating operation respectively
has been selected is posed. To this end, in "automatic" mode the status of the various
emitters E3 to E7 will be addressed, whereas in "manual" mode the status of the left
hand treadle is interrogated. In the event that neither a snipping nor a pleating
operation has been selected then at 740 the appropriate drive signal is supplied to
motor SM2 to achieve the adhesive supply rate as determined at step 734. In the event
that either a snipping or a pleating operation has been selected, then at step 742
the calculated adhesive supply rate required is again modified according to the setting
of the appropriate one of selector devices SS2 and SS3. In this regard it will be
noted that the setting of the desired adhesive supply rate will be applicable whenever
"normal" feeding of the workpiece is taken place, as determined by the setting of
selector device SS1. The modification of the delivery rate in accordance with the
setting of either one of devices SS2 and SS3 will be proportional, in the same ratio
as that between the settings of the selected device and device SS1. Thereafter, at
step 744, the adhesive supply rate as determined at step 734 is modified by this further
modification factor and thereafter the appropriate drive signal is supplied to motor
SM2 (step 740).
[0038] Figure 6 indicates further aspects of the software relating to the adjustment of
feed length which will take place during the operating cycle of the machine. It will
thus be appreciated that, as with the sections of software to which Figures 4 and
5 also relate, these sub-programs are access regularly and frequently during the general
operation of the machine as set out in Figure 3. The particular sub-program is brought
into effect only if a change in feed length is indicated, either by a signal from
the emitters E3 to E7 or a signal from the left hand treadle, depending on the particular
mode of operation of the machine. In the event that a new feed length is indicated
then at step 750 the question is posed as to whether a feed length change is currently
taking place. If so, then at step 752 an instruction to wait for the current change
to be completed is supplied. At step 754 the displacement of the feed length control
lever necessary to bring about the required change of feed length is calculated in
terms of steps of stepping motor SM1 by which the position of the lever is varied.
It is the intention that any change of feed length which takes place during the operating
cycle of the machine, i.e. when the machine is actually running, is effected smoothly
as opposed to previous machines in which the change has been effectively instantaneous,
leading to "snatching" of the workpiece as the change takes place. If, however, the
motor M1 is not in fact operating at the time of the feed length change, as checked
at step 756, then the feed length change can be promptly executed and to this end
at step 758 the motor feed speed is treated as at the maximum so that the change of
feed length is effected in the quickest possible time. In the event that the machine
is operating at the time then the actual speed of rotation of the main drive shaft
is calculated using shaft encoder E (step 760). Whichever information is thus supplied,
at step 762 the stepping rate of stepping motor SM2 required to displace the feed
length control lever through the appropriate distance within a pre-set number of,
e.g. 3, revolutions of the main drive shaft (which will give an allowed time dependent
upon the speed of rotation of the drive shaft as calculated at step 760 or set at
step 758) is calculated, such calculation being of course dependent upon the maximum
stepping rate limit for the motor SM2. In the event that the stepping motor cannot
achieve the stepping rate required, then it will be operated at a maximum speed to
achieve the change of feed length in the smallest time commensurate with that speed.
[0039] If desired, the change in the rate of adhesive supply corresponding to the feed length
change may also be similarly "phased" to achieve a smooth transition.
1. Folding machine comprising
a main drive shaft driven by a motor (M1),
folding instrumentalities (12,14,16,22,30) arranged at an operating locality of
the machine,
workpiece feeding means operable in timed relation with the rotation of the main
drive shaft for feeding a workpiece to be folded through the operating locality, and
operator-controlled feed speed variation means (T) for varying the speed of rotation
of the main drive shaft,
characterised in that the motor (M1) for the main drive shaft is an a.c. induction
motor provided with an inverter (I),
and in that the feed speed variation means (T) comprises a transducer (T) providing
an analogue output which is variable according to the setting of the transducer under
operator control,
the machine being further characterised by an analogue-to-digital converter (ADC)
which receives the analogue output of the transducer (T) and converts it to a digital
value which is thus variable in accordance with the setting of the transducer (T),
computer control means for receiving the digital value and for modifying it in
accordance with one or more inputs (SS7, 714) each in the form of a signal having
a value determined according to an operational setting of the folding machine, and
a digital-to-analogue converter for converting the digital value, thus modified,
to an analogue drive signal which is supplied to the inverter (I), such that the speed
of rotation of the a.c. motor (M1), and thus of the main drive shaft, is determined
in accordance with the setting of the transducer (T), but modified in accordance with
one or more of said inputs.
2. Machine according to Claim 1 wherein the workpiece feeding means comprises an orbitally
movable hammer-and-anvil arrangement driven by the main drive shaft,
characterised in that the output of the transducer (T) corresponds, according to its
value, to a "stop" condition, a "drive" condition or a condition in which the operation
of the machine is stopped with the hammer-and-anvil in a closed condition.
3. Machine according to Claim 1 or Claim 2 wherein monitoring means (E) is provided whereby
the speed of rotation of the main drive shaft is monitored, characterised in that
the drive signal supplied to the inverter (I) from the computer control means is modified
by an input from the monitoring means (E) if and to the extent that the actual speed
of rotation as monitored does not match the notional speed which corresponds to the
particular setting of the transducer (T), such modification being such as to effect
matching of said actual speed with said notional speed.
4. Machine according to any one of Claims 1 to 3 characterised by speed range variation
means (SS7) which provides an input to the computer control means whereby the speed
range, within which the speed of rotation of the main drive shaft can be varied under
the control of the operator as aforesaid, can be varied, the variation being proportional
in respect of any setting of the feed speed variation means such that for a given
such setting the speed of rotation of the main drive shaft will vary in accordance
with the proportion set by the speed range variation means.
5. Machine according to Claim 4 wherein a maximum speed is set for the output speed of
the motor (M1) and thus for the rotation of the main drive shaft, characterised in
that the speed range variation means is effective to select a speed range having a
maximum which represents a proportion of the thus set maximum.
6. Machine according to any one of the preceding Claims wherein feed length variation
means is provided for varying the distance through which a workpiece is fed by the
workpiece feeding means for each rotation of the main drive shaft, characterised in
that the feed length variation means comprises an n.c. motor (SM1) operation of which
is effective, in response to control signals supplied by the computer control means,
to displace a feed length control lever whereby to cause the feed length to be varied,
and in that the computer control means calculates the rate at which a feed length
variation is to take place based upon the required displacement of said lever to achieve
a desired feed length variation and also the speed of rotation of the main drive shaft.
7. Machine according to any one of the preceding Claims further comprising
adhesive supply means (SM2,22 to 28), including a gear pump (26) driven by an n.c.
motor (SM2), for supplying adhesive to portions of a workpiece to be folded as it
is fed through the operating locality by the workpiece feeding means, the computer
control means supplying to said n.c. motor (SM2) a drive signal the value of which
is dependent upon the speed of rotation of the main drive shaft and the operational
state of the feed speed variation means (-,SM1),
characterised in that said drive signal, and thus the rate of adhesive supply, is
dependent upon the value of the digital signal supplied to the computer control means,
but modified as aforementioned.
8. Machine according to Claim 7 wherein operator-actuatable means (SS9) is provided for
setting the rate of adhesive supply, characterised in that said means (SS9) is effective
to supply a signal, the value of which varies according to the selected setting, to
the computer control means, and in that the value of the drive signal supplied by
the computer control means to the n.c. motor (SM2) for the gear pump (26) is thus
dependent also upon the value of the signal supplied by the adhesive supply rate setting
means (SS9).
9. Machine according to Claim 8 characterised in that operator-actuatable means (SS1,SS2,SS3)
is provided which provides an input to the computer control means and by which a plurality
of pre-settings can be made for the workpiece feed length for selection according
to the contour of the workpiece edge to be folded, the arrangement being such that
the feed length variation means (-,SM1) is effective to set the feed length in accordance
with a selected one of such settings upon receipt of an appropriate signal from the
computer control means,
and in that one of the pre-set feed lengths is used as a standard and selection thereof
is ineffective to vary the rate of adhesive supply as set by the operator-actuatable
adhesive supply rate setting means (SS9), but the selection of another of the pre-settings
is effective to cause said rate to be varied, such variation being proportional to
the difference between the standard and the selected pre-set feed lengths.
10. Machine according to Claim 5 and 9 wherein workpiece detecting devices (E1 to E7)
are disposed at or adjacent the operating locality of the machine and comprising a
"workpiece present" detecting device (E1,E2) which serves to detect the presence of
a workpiece, and thus cause the supply of adhesive to be initiated, and also a "corner"
detecting device (E3 to E7) which serves to detect the approach of both "outside"
and "inside" corners (as hereinbefore defined) to the operating locality as the workpiece
is being fed therethrough,
characterised in that in response to detection of an approaching corner an input is
provided to the computer control means whereby an appropriate one of the pre-set feed
lengths is selected,
and in that operator-actuatable means (S11) is provided by which an input is provided
to the computer control means whereby the feed speed variation means (T) is disabled
and the "workpiece present" detecting device (E1,E2) is enabled to initiate also operation
of the workpiece feeding means when the presence of a workpiece is detected thereby,
the speed of rotation of the main drive shaft being set at the maximum within the
selectively set speed range and the various pre-set feed lengths being selected according
to the contour of the workpiece edge as detected by the "corner" detecting device
(E3 to E7).
1. Umbugmaschine, die
eine durch einen Motor (M1) angetriebene Hauptantriebswelle umfaßt,
Umbugelemente (12, 14, 16, 22, 30), die in einem Arbeitsbereich der Maschine angebracht
sind,
eine Arbeitsstück-Vorschubeinrichtung, die in zeitlich abgestimmter Relation mit
der Drehung der Hauptantriebswelle betrieben wird, um ein umzubuggendes Arbeitsstück
durch den Arbeitsbereich zu transportieren und
eine durch die Arbeitskraft zu betätigende Einrichtung zum Ändern der Vorschubgeschwindigkeit
(T), um die Drehzahl der Hauptantriebswelle zu verändern,
dadurch gekennzeichnet, daß der Motor (M1) für die Hauptantriebswelle ein mit einem
Frequenzumformer (I) ausgestatteter Wechselspannungs-Induktionsmotor ist,
und dadurch, daß die Einrichtung zum Ändern der Vorschubgeschwindigkeit (T) einen
Signalumformer (T) umfaßt, der mit einem Analog-Ausgang ausgestattet ist, welcher
entsprechend der Einstellung des Signalumformers durch die Arbeitskraft gesteuert
verändert werden kann,
wobei die Maschine darüberhinaus durch einen Analog-Digital-Umwandler (ADC) gekennzeichnet
ist, welcher den Analog-Ausgang des Signalumformers (T) erhält und ihn in einen digitalen
Wert umwandelt, der somit entsprechend der Einstellung des Signalumformers (T) verändert
werden kann,
eine Computersteuerungs-Einrichtung, um den Digitalwert aufzunehmen und ihn in
Übereinstimmung mit einem oder mehreren Eingängen (SS7, 714) zu ändern, jeweils in
Form eines Signals mit einem entsprechend einer Betriebseinstellung der Umbugmaschine
festgelegten Wert
und einen Digital-Analog-Umwandler, um den so geänderten Digitalwert zu einem Analog-Antriebssignal
umzuwandeln, welches zum Frequenzumformer (I) geliefert wird, sodaß die Drehzahl des
Wechselstrommotors (M1), und somit der Hauptantriebswelle, entsprechend der Einstellung
des Signalumformers (T), jedoch in Übereinstimmung mit einem oder mehreren der genannten
Eingänge geändert, festgelegt wird.
2. Maschine gemäß Anspruch 1, bei welcher die Arbeitsstück-Vorschubeinrichtung eine durch
die Hauptantriebswelle angetriebene, sich kreisförmig bewegende Hammer- und Amboß-Einrichtung
umfaßt,
dadurch gekennzeichnet, daß der Ausgang des Signalumformers (T) entsprechend seines
Wertes einem "Stopp"-Zustand, einem "Antriebs"-Zustand oder einem Zustand, bei welchem
der Betrieb der Maschine mit der Hammer- und Amboß-Einrichtung in geschlossenem Zustand
gestoppt wird, entspricht.
3. Maschine gemäß Anspruch 1 oder Anspruch 2,
in welcher eine Kontrolleinrichtung (E) zur Verfügung steht, durch welche die Drehzahl
der Hauptantriebswelle überwacht wird,
dadurch gekennzeichnet, daß das von der Computersteuerungseinheit zum Frequenzumformer
(I) gelieferte Antriebssignal durch einen Eingang von der Kontrolleinrichtung (E)
geändert wird, wenn und soweit die bei der Überwachung festgestellte aktuelle Drehzahl
nicht mit der Nominal-Drehzahl, die der speziellen Einstellung des Signalumformers
(T) entspricht, übereinstimmt, wobei eine solche Änderung derart erfolgt, daß die
genannte aktuelle Drehzahl mit der genannten Nominal-Drehzahl übereinstimmt.
4. Maschine gemäß einem der Ansprüche 1 bis 3,
gekennzeichnet durch eine Einrichtung zum Ändern des Geschwindigkeitsbereichs (SS7),
welche einen Eingang zur Computersteuerungseinrichtung zur Verfügung stellt, durch
welche der Geschwindigkeitsbereich, innerhalb dessen die Drehzahl der Hauptantriebswelle
wie oben erwähnt von der Arbeitskraft gesteuert verändert werden kann, verändert werden
kann, wobei die Veränderung in Bezug auf jede Einstellung der Einrichtung zum Ändern
der Vorschubgeschwindigkeit proportional ist, sodaß sich die Drehzahl der Hauptantriebswelle
für eine solche bestehende Einstellung in Übereinstimmung mit der durch die Einrichtung
zum Ändern der Geschwindigkeitsstufe eingestellten Proportion verändert.
5. Maschine gemäß Anspruch 4, bei welcher eine Maximalgeschwindigkeit für die Ausgangsgeschwindigkeit
des Motors (M1) und somit für die Drehung der Hauptantriebswelle eingestellt wird,
dadurch gekennzeichnet, daß die Einrichtung zum Ändern des Geschwindigkeitsbereichs
bewirkt, daß ein Geschwindigkeitsbereich mit einem Maximalwert ausgewählt wird, welcher
proportional zu dem so eingestellten Maximalwert ist.
6. Maschine gemäß einem der oben erwähnten Ansprüche, bei welcher eine Einrichtung zum
Ändern der Vorschublänge zur Verfügung steht, um die Strecke, um welche ein Arbeitsstück
von der Arbeitsstück-Vorschubeinrichtung bei jeder Drehung der Hauptantriebswelle
vorgeschoben wird, zu verändern,
dadurch gekennzeichnet, daß die Einrichtung zum Ändern der Vorschublänge einen
NC-Motor (SM1) umfaßt, dessen Betrieb als Reaktion auf durch die Computersteuerungseinrichtung
gelieferte Steuerungssignale bewirkt, daß ein Vorschublängen-Steuerungshebel verschoben
wird, um dadurch die Vorschublänge zu verändern,
und dadurch, daß die Computersteuerungseinrichtung die Stufe berechnet, mit der
eine Änderung der Vorschublänge stattfinden soll, auf der Basis der erforderlichen
Verschiebung des genannten Hebels, um eine gewünschte Änderung der Vorschublänge zu
erreichen und auch die Drehzahl der Hauptantriebswelle.
7. Maschine gemäß einem der oben erwähnten Ansprüche, die darüberhinaus
eine Klebstoffzuführeinrichtung (SM2, 22 bis 28) mit einer von einem NC-Motor (SM2)
angetriebenen Zahnradpumpe (26) umfaßt, um Klebstoff zu den umzubuggenden Abschnitten
eines Arbeitsstücks zu transportieren, während es durch die Arbeitsstück-Vorschubeinrichtung
durch den Arbeitsbereich der Maschine transportiert wird, wobei die Computersteuerungs-Einrichtung
zu dem genannten NC-Motor (SM2) ein Antriebssignal liefert, dessen Wert von der Drehzahl
der Hauptantriebswelle und dem Betriebszustand der Einrichtung zum Ändern der Vorschubgeschwindigkeit
(-, SM1) abhängt,
dadurch gekennzeichnet, daß das genannte Antriebssignal, und somit die Klebstofftransportstufe,
vom Wert des zu der Computersteuerungs-Einrichtung gelieferten digitalen Signals,
das jedoch wie oben erwähnt geändert wird, abhängt.
8. Maschine gemäß Anspruch 7, bei welcher eine durch die Arbeitskraft zu betätigende
Einrichtung (SS9) zur Verfügung steht, um die Klebstofftransportrate einzustellen,
dadurch gekennzeichnet, daß die genannte Einrichtung (SS9) bewirkt, daß ein Signal,
dessen Wert sich entsprechend der ausgewählten Einstellung verändert, zu der Computersteuerungs-Einrichtung
geliefert wird,
und dadurch, daß der von der Computersteuerungs-Einrichtung zum NC-Motor (SM2)
gelieferte Wert des Antriebssignals für die Zahnradpumpe (26) somit auch vom Wert
des von der Einstelleinrichtung du Klebstoffzuführrate (SS9) gelieferten Signals abhängt.
9. Maschine gemäß Anspruch 8,
dadurch gekennzeichnet, daß eine durch die Arbeitskraft zu betätigende Einrichtung
(SS1, SS2, SS3) zur Verfügung steht, die mit einem Eingang zu der Computersteuerungs-Einrichtung
ausgestattet ist, und durch welche mehrere entsprechend der Kontur der umzubuggenden
Arbeitsstückkante auswählbare Voreinstellungen für die Arbeitsstück-Vorschublänge
vorgenommen werden können, wobei die Anordnung derart ist, daß die Einrichtung zum
Ändern der Vorschublänge (-, SM1) bewirkt, daß die Vorschublänge nach Erhalt eines
entsprechenden Signals von der Computersteuerungs-Einrichtung in Übereinstimmung mit
einer solchen ausgewählten Einstellung eingestellt wird,
und dadurch, daß eine der voreingestellten Vorschublängen standardmäßig verwendet
wird und die Auswahl dieser Vorschublänge die durch die von der Arbeitskraft zu betätigende
Einstelleinrichtung für die Klebstoffzuführrate (SS9) eingestellte Klebstoffzuführrate
nicht verändert, die Auswahl einer anderen der Voreinstellungen jedoch bewirkt, daß
die genannte Rate verändert wird, wobei eine solche Änderung proportional zur Differenz
zwischen der standardmäßigen und der ausgewählten voreingestellten Vorschublänge ist.
10. Maschine gemäß Anspruch 5 und 9, bei welcher Arbeitsstück-Detektor-Einrichtungen (E1
bis E7) an oder neben dem Arbeitsbereich der Maschine angebracht sind und eine Detektoreinrichtung
"Arbeitsstück vorhanden", (E1, E2) umfassen, welche dazu dient, zu erfassen, ob ein
Arbeitsstück vorhanden ist, und damit bewirken, daß der Klebstofftransport gestartet
wird, und auch eine "Kanten"-Detektor-Einrichtung (E3 bis E7), die dazu dient, die
Annäherung sowohl von "Außen"-, als auch von "Innen"-bögen (wie an früherer Stelle
beschrieben) an den Arbeitsbereich zu erfassen, während das Arbeitsstück durch diesen
transportiert wird,
dadurch gekennzeichnet, daß aufgrund es Erfassens einer sich annähernden Kante
ein Eingang zu der Computersteuerungs-Einrichtung gebildet wird, wodurch eine geeignete
der vorgewählten Vorschublängen ausgewählt wird,
und dadurch, daß eine durch die Arbeitskraft zu betätigende Einrichtung (S11) zur
Verfügung steht, welche mit einem Eingang zur Computersteuerungs-Einrichtung ausgestattet
ist, wodurch der Einrichtung zum Ändern der Vorschubgeschwindigkeit (T) die Wirkung
genommen und die Detektor-Einrichtung "Arbeitsstück vorhanden" (E1, E2) wirksam wird,
um, wenn diese erfaßt, daß ein Arbeitsstück vorhanden ist, auch den Betrieb der Arbeitsstück-Vorschubeinrichtung
zu starten, wobei die Drehzahl der Hauptantriebswelle innerhalb des wahlweise eingestellten
Geschwindigkeitsbereichs auf maximal eingestellt ist und die verschiedenen voreingestellten
Vorschublängen entsprechend der durch die "Kanten"-Detektor-Einrichtung (E3 bis E7)
erfaßten Kontur des Arbeitsstücks ausgewählt werden.
1. Machine à plier comprenant
un arbre menant principal entraîné par un moteur (M1),
des instruments de pliage (12, 14, 16, 22, 30) disposés à un emplacement de travail
de la machine,
un moyen d'alimentation de pièces à travailler capable de fonctionner en relation
synchronisée avec la rotation de l'arbre menant principal pour faire passer une pièce
à travailler devant être pliée par l'emplacement de travail, et
un moyen (T) de variation de vitesse d'alimentation commandé par l'opérateur, servant
à faire varier la vitesse de rotation de l'arbre menant principal,
caractérisée en ce que le moteur (M1) pour l'arbre menant principal est un moteur
à induction à courant alternatif pourvu d'un onduleur (I),
et en ce que le moyen de variation de vitesse d'alimentation (T) comprend un transducteur
(T) produisant une sortie analogique qui est variable selon le réglage du transducteur
sous la commande de l'opérateur,
la machine étant en outre caractérisée par un convertisseur analogique-numérique (ADC)
qui reçoit la sortie analogique du transducteur (T) et la convertit en une valeur
numérique qui est ainsi variable selon le réglage du transducteur (T),
un moyen de commande par ordinateur servant à recevoir la valeur numérique et à la
modifier selon une ou plusieurs entrées (SS7, 714) chacune sous forme d'un signal
ayant une valeur déterminée selon un réglage d'exploitation de la machine à plier,
et un convertisseur numérique-analogique servant à convertir la valeur numérique,
ainsi modifiée, en un signal de commande analogique qui est fourni à l'onduleur (I),
de telle sorte que la vitesse de rotation du moteur à courant alternatif (M1), et
donc de l'arbre menant principal, est déterminée selon le réglage du transducteur
(T) mais modifiée selon une ou plusieurs desdites entrées.
2. Machine selon la revendication 1, dans laquelle le moyen d'alimentation de pièces
à travailler comprend un arrangement à marteau-enclume mobile de manière orbitale
et entraîné par l'arbre menant principal,
caractérisée en ce que la sortie du transducteur (T) correspond, selon sa valeur,
à un état d'"arrêt", un état de "marche" ou un état dans lequel le travail de la machine
s'arrête, l'arrangement à marteau-enclume étant dans un état fermé.
3. Machine selon la revendication 1 ou la revendication 2, dans laquelle on prévoit un
moyen de surveillance (E) grâce auquel on surveille la vitesse de rotation de l'arbre
menant principal, caractérisée en ce que le signal de commande fourni à l'onduleur
(I) en provenance du moyen de commande par ordinateur est modifié par une entrée provenant
du moyen de surveillance (E) si et dans la mesure où la vitesse réelle de rotation
telle que surveillée ne correspond pas à la vitesse fictive qui correspond au réglage
particulier du transducteur (T), une telle modification étant de nature à effectuer
une mise en correspondance de ladite vitesse réelle et de ladite vitesse fictive.
4. Machine selon l'une quelconque des revendications 1 à 3, caractérisée par un moyen
de variation de gamme de vitesses (SS7) qui fournit une entrée au moyen de commande
par ordinateur grâce auquel on peut faire varier la gamme de vitesses dans les limites
de laquelle on peut faire varier la vitesse de rotation de l'arbre menant principal
sous la commande de l'opérateur comme susmentionné, la variation étant proportionnelle
à tout réglage du moyen de variation de vitesse d'alimentation de sorte que pour un
réglage donné de ce type la vitesse de rotation de l'arbre menant principal variera
selon la proportion réglée par le moyen de variation de gamme de vitesses.
5. Machine selon la revendication 4, dans laquelle on règle une vitesse maximale pour
la vitesse de sortie du moteur (M1) et donc pour la rotation de l'arbre menant principal,
caractérisée en ce que le moyen de variation de gamme de vitesses sert à sélectionner
une gamme de vitesses ayant une valeur maximale qui représente une proportion de la
valeur maximale ainsi réglée.
6. Machine selon l'une quelconque des revendications précédentes, dans laquelle on prévoit
un moyen de variation de longueur d'alimentation servant à faire varier la distance
sur laquelle une pièce à travailler est alimentée par le moyen d'alimentation de pièces
à travailler pour chaque rotation de l'arbre menant principal,
caractérisée en ce que le moyen de variation de longueur d'alimentation comprend un
moteur à commande numérique (SM1) dont la mise en service sert, en réponse à des signaux
de commande fournis par le moyen de commande par ordinateur, à déplacer un levier
de commande de longueur d'alimentation pour ainsi provoquer la variation de la longueur
d'alimentation, et en ce que le moyen de commande par ordinateur calcule la vitesse
à laquelle doit avoir lieu une variation de longueur d'alimentation sur la base du
déplacement requis dudit levier afin d'obtenir une variation de longueur d'alimentation
désirée et également la vitesse de rotation de l'arbre menant principal.
7. Machine selon l'une quelconque des revendications précédentes, comprenant en outre
un moyen d'alimentation en adhésif (SM2, 22 à 28), comportant une pompe à engrenages
(26) entraînée par un moteur à commande numérique (SM2), servant à alimenter en adhésif
des portions d'une pièce à travailler devant être pliée lorsque le moyen d'alimentation
de pièces à travailler la fait passer par l'emplacement de travail, le moyen de commande
par ordinateur fournissant audit moteur à commande numérique (SM2) un signal de commande
dont la valeur dépend de la vitesse de rotation de l'arbre menant principal et de
l'état d'exploitation du moyen de variation de vitesse d'alimentation (-, SM1),
caractérisée en ce que ledit signal de commande, et ainsi la vitesse d'alimentation
en adhésif, dépend de la valeur du signal numérique fourni au moyen de commande par
ordinateur, mais modifié comme susmentionné.
8. Machine selon la revendication 7, dans laquelle on fournit un moyen actionnable par
l'opérateur (SS9) servant à régler la vitesse d'alimentation en adhésif, caractérisée
en ce que ledit moyen (SS9) sert à fournir un signal, dont la valeur varie selon le
réglage sélectionné, au moyen de commande par ordinateur, et en ce que la valeur du
signal de commande fourni par le moyen de commande par ordinateur au moteur à commande
numérique (SM2) pour la pompe à engrenages (26) dépend ainsi également de la valeur
du signal fourni par le moyen de réglage de vitesse d'alimention en adhésif (SS9).
9. Machine selon la revendication 8, caractérisée en ce qu'on prévoit un moyen actionnable
par l'opérateur (SS1, SS2, SS3), qui fournit une entrée au moyen de commande par ordinateur
et grâce auquel on peut effectuer une pluralité de pré-réglages pour la longueur d'alimentation
des pièces à travailler à sélectionner selon le contour du bord de la pièce à travailler
devant être pliée, l'arrangement étant tel que le moyen de variation de longueur d'alimentation
(-, SM1) sert à régler la longueur d'alimentation selon un réglage sélectionné parmi
ces réglages lors de la réception d'un signal approprié en provenance du moyen de
commande par ordinateur,
et en ce qu'on utilise comme norme l'une des longueurs d'alimentation pré-réglées
et la selection de celle-ci est inefficace pour faire varier la vitesse d'alimentation
en adhésif telle que réglée par le moyen de réglage de vitesse d'alimentation en adhésif
actionnable par l'opérateur (SS9), mais la sélection d'un autre parmi les pré-réglages
est efficace pour provoquer la variation de ladite vitesse, cette variation étant
proportionnelle à la différence entre la norme et les longueurs d'alimentation pré-réglées
sélectionnées.
10. Machine selon la revendication 5 et la revendication 9, dans laquelle des dispositifs
de détection de pièces à travailler (E1 à E7) sont disposés au niveau de ou adjacents
à l'emplacement de travail de la machine et comprenant un dispositif de détection
de "présence de pièce à travailler" (E1, E2) qui sert à détecter la présence d'une
pièce à travailler, et ainsi provoque le déclenchement de l'alimentation en adhésif,
et également un dispositif de détection de "coin" (E3 à E7) qui sert à détecter l'approche
à la fois de coins "intérieurs" et "extérieurs" (tels que définis plus haut) pour
l'emplacement de travail lorsque la pièce à travailler est alimenté par celui-ci,
caractérisée en ce qu'en réponse à la détection d'un coin approchant, une entrée est
fournie au moyen de commande par ordinateur, grâce à laquelle une longueur appropriée
est sélectionnée parmi les longueurs d'alimentation pré-réglées, et en ce qu'on prévoit
un moyen actionnable par l'opérateur (S11), grâce auquel on fournit une entrée au
moyen de commande par ordinateur, grâce à laquelle le moyen de variation de vitesse
d'alimentation (T) est mis hors service et le moyen de détection de "présence de pièce
à travailler" (E1, E2) est mis en service pour commencer également le travail du moyen
d'alimentation de pièces à travailler lorsque la présence d'une pièce à travailler
est détectée par celui-ci, la vitesse de rotation de l'arbre menant principal étant
réglée à la valeur maximale dans les limites de la gamme de vitesses réglée sélectivement
et les diverses longueurs d'alimentation pré-réglées étant sélectionnées selon le
contour du bord de la pièce à travailler tel que détecté par le dispositif de détection
de "coin" (E3 à E7).