[0001] This invention relates to a yarn feeding finger control device for a circular knitting
machine, in particular a single cylinder hose knitting machine, comprising a plurality
for yarn feeding fingers individually pivoted to a stationary structure of the machine
and selectively movable between a rest position, whereat one yarn feeding end thereof
is moved away from the needles and the respective yarn is not picked up by the latter,
and an operative position, whereat said end is moved close to the . needles and the
latter pick up the yarn, the selective movement being accomplished through program
controlled means.
[0002] Devices of the above general type are well known to the experts, e.g. from US Patents
No.s 1,763,378 and 1,938,673. The means for selectively actuating the yarn feeding
fingers comprise in general a plurality of cams arranged circumferentially around
a machine drum in accordance with the yarn feeding fingers program for operation,
and a system of levers and tie rods arranged between the cams and respective yarn
feeding fingers.
[0003] A device of this kind requires, therefore, as many cams along the drum periphery
as are the yarn feeding fingers. Assuming a machine with plural feeds, there are to
be found as many groups of cam rows as are the feeds, thus resulting in a drum of
considerable bulk. Moreover, the linkage system is also bulky as well as being complex,
since each set of levers and tie rods associated with a yarn feeding finger must be
indipendent of the others.
[0004] This situation remains substantially unaltered where the tie rods are replaced with
Bowden cables, as it is usual with double cylinder machines.
[0005] A primary object of this invention is to provide a drive device of the type indicated
in the preamble, which is significantly less bulky than conventional ones, requires
virtually no space around the periphery of the machine main drum, or any other drums
thereof, and can bring about less advancement movements of the drum on behalf of other'
machine controls.
[0006] Another object of the invention is to provide a device of the type mentioned in the
preamble, which can even be controlled, instead by the machine drum, by some other
programming means.
[0007] .These and other objects, such as will be apparent hereinafter, are all achieved
by a yarn feeding finger control device for a circular knitting machine of the type
mentioned in the preamble, characterized in that with the yarn feeding fingers there
are associated respective electromagnets for moving said yarn feeding fingers, and
that a means is provided for detecting the movement of a mechanical programming member
of the machine, as well as a memory device electrically connected to said detecting
means and driven thereby to selectively energize and de-energize individual electromagnets
in accordance with the advancing movement of
'said mechanical programming member of the machine.
[0008] Advantageously, the mechanical programming member may be the machine main drum, and
the detecting means may comprise a photoelectric unit adapted for sending electric
pulses to the memory device at each advance step of the drum, the memory device controlling,
selectively and sequentially, the energization and de-energization of the individual
electromagnets and, accordingly, the intervention and withdrawal of the various yarn
feeding fingers in accordance with the pulse sequence from the photoelectric unit.
[0009] In a device of this type, the machine main drum (or other equivalent drum) no longer
requires, to drive the yarn feeding fingers, any cams along its periphery and can
thus be made smaller in size or utilized to drive other machine members, thus extending
the knitting capabilities of the machine. It will be sufficient, for example, to provide
a disk rigid with the drum and having a peripheral arrangement of plural notches for
each advancing movement of the drum during a full revolution, the notch succession
supplying, during the drum advancing movement and through a pair of photo-elements
in the photoelectric unit, electric pulses for driving the memory. In the memory,
there is stored the knitting program, and the driving of the memory by the detecting
means causes each given pulse, from a setting or reference position or upon completion
of ascertain number of pulses starting from that position, to produce an energization
or de-energization control impulse for a given electromagnet, thus controlling to
knit or withdrawing from knitting the respective yarn feeding finger. It will be appreciated,
therefore, that all of the lever and tie rod and/or Bowden cable systems are eliminated,
thus leaving a significant clear space peripherally to the machine and facilitating
access to parts thereof. The electromagnets easily find room under the yarn feeding
fingers. If desired, the ends of the yarn feeding fingers associated with the electromagnets
may be bent outwardly from the plane of movement of the yarn feeding fingers, should
the available room for the electromagnets prove insufficient.
[0010] Further details and advantages of the invention will be more readily apparent from
the following detailed description of one embodiment thereof, illustrated in the accompanying
drawings, where:
Figure 1 is a perspective view of a yarn feeding finger group according to the invention;
Figure 2 is a perspective view of the detecting means associated with the machine
drum;
Figures 3 and 4 show one yarn feeding finger and the electromagnet associated therewith,
respectively in the operative and inoperative positions; and
Figure 5 is a block diagram of the memory device intervening between the detecting
means and yarn feeding fingers.
[0011] As shown more clearly in Figure 1, a feeding group 1 of a circular knitting machine,
in particular a single cylinder hose knitting machine, comprises a plurality of yarn
feeding fingers 2 individually pivoted at 3 to a structure 4, in turn secured to the
stationary portion of the machine (not shown). The yarn feeding fingers 2 are each
provided, in a manner known per se, with a work end 2a, formed with guiding means
in the form of holes or small tubes 5 for a respective yarn 6, the end 2a being movable
between a rest position (Figure 4), whereat the end 2a is moved away from the needles
7 and the related yarn 6 is not picked up by them, and an operative position (Figure3)
whereat said end 2a is moved closer to the needles 7 and the latter pick up the yarn
6. The reference numeral 8 designates a yarn guiding plate having holes 9 ' therein
for the individual yarns 6 which are supplied from bobbins or reels, not shown.
[0012] The control ends 2b of the feeding fingers, opposed to the work ends2a, are urged
by respective springs 10 (for clarity reasons, only one of them has been represented
in Figure 1) stretched between the ends 2b and stationary structure'4 such as to hold
the yarn feeding fingers 2 normally in their rest positions. Advantageously, the ends
2b of the yarn feeding fingers which are located on either sides of the middle or
center feeding finger are bent outwardly to extend in different planes from the movement
planes of the respective yarn feeding fingers 2. This in order to permit electromagnets
11 to be arranged at these ends, in particular below them, as shown in Figure 1. For
space reasons, the electromagnets 11 are staggered in several rows, e.g. with two
of them further outboard and three further inboard along the radial direction of the
machine. They are secured to the structure 4 by means not shown and act on the yarn
feeding fingers 2 with their respective rod armatures 12, which urge the yarn feeding
fingers 2 from their rest positions (Figure 4) into their operative ones (Figure 3)
upon energization of the electromagnets 11. With the yarn feeding fingers 2 in their
rest positions, the electromagnets 11 are de-energized and the armatures'12 drawn
back.
[0013] According to the invention, for controlling the yarn feeding fingers, that is to
selectively energize and de-energize the individual electromagnets 11, provision is
made for a means13 for detecting the movement of a mechanical programming member of
the machine, in particular of the machine main drum 14, as shown in Figure 2, and
a memory device 15, illustrated in block diagram form in Figure 5, which is electrically
connected to the detecting means 13 through leads 16 and driven by such means to selectively
energize and de-energize the individual electromagnets 11 as a function of the advancing
movement of the mechanical programming member 14.
[0014] For the detecting means, a disk 17 rotatively rigid with the drum 14 on one side
thereof and provided peripherally with a plurality of notches 18, and a photoelectric
unit 19, secured to straddle the disk 17 to a holder 20, are provided. The notches
18 are preferably equispaced and in a multiple number of the advancing steps of the
drum, e.g. five notches per advancing step of the drum. The photoelectric unit 19which
comprises a photoemitter element and photoreceiver one, of a type known per se, is,
mounted stationary with respect to the disk 17, and is connected to the memory device
15 through the cited leads 16. It will be appreciated that each advancing step of
the drum 14, which is conventionally driven by means of pawls, not shovm, results
in the supply of one or more electric pulses to the memory device 15, depending on
the number of notches 18 which move past the photoelectric unit 19 during each advancing
step of the drum.
[0015] The pulses are passed to the memory device 15 through a peripheral interface adapter
21, of a type known per se.. The memory device 15 contains a knitting program in accordance
wherewith, to the sequence of pulses from the detecting means 13 starting with the
zero or setting time and up to the time when knitting commences on the machine, there
correspond a sequence of selective energization and de-energization impulses to the
electromagnets 11.
[0016] The device 15 essentially comprises a microprocessor 22, a pair of random access
memories (RAM) 23,24, a read-only memory (ROM) 25, and some peripheral interface adapters
26,27,28, in addition to the cited adapter 21. Also provided is a keyboard 29 for
program writing, which is connected to the group through the adapter 26, while a display
unit 30, connected to the group through the adapter 27, enables the machine rpm to
be displayed visually. The group control output is represented by the adapter 28,
which controls a number of amplifiers 31, whereto the electromagnets 11 are connected
respectively through the leads 32. The group of elements just described is fed through
a power supply 33 or battery 34, the microprocessor 22 being driven by a crystal oscillator
35. The device components are respectively connected through the connections 36 and
37, the former being the data bus and the latter the address bus.
[0017] The microprocessor 22 will process and check the data from the machine, as well as
those set on the keyboard 29, in accordance with the machine knitting program, and
compare them upon occurrence to those in the various storage devices. More specifically,
the read-only memory 25 contains the basic program, which is each time adapted to
suit specific knitting requirements by means of the random access memories 23,24.
Thus, the device is made extremely versatile and suitable for a high number of knitting
programs.
[0018] The various components of the device are electronic components which are readily
available " on the market, and will require no further discussion herein, also because
the memory device just described is not a part of this invention.
[0019] In actual practice, the device will be set for knitting by writing on the keyboard
29 the knitting program, in the sense that each advance movement of the drum 14, in
turn related to the progressive number of revolutions of the machine and accordingly
to each pulse or series of pulses from the detecting means 13, is made to correspond
to a state of energization or de-energization of each electromagnet 11 in accordance
with the knitting program. Thereafter, the yarn feeding fingers 2 are automatically
selected in accordance with the knitting instant. In other words, each time that a
pulse is supplied by the detecting means 13, the memory device 15 will hold or change
the state of one or more electromagnets 11 in accordance with the preset program.
It should be noted that with the drum 14 at a standstill, the controls to the electromagnets
are maintained. Of course, they may also be maintained during the motion of the drum
14, if the stored program does require it. It is also noteworthy that the fine distribution
of the notches 18 affords the possibility of providing several controls within a single
advancing step of the drum in very quick succession. Thus, one is enabled to select
with a high accuracy the time instant of insertion to knit of a yarn feeding finger
2 and time instant of withdrawal from knitting of another yarn feeding finger 2. In
all cases, the operation of the memory device 15 affords high simultaneous control
number capabilities with even a single pulse, whereas conventional machines would
require, for the same purpose, the provision of a high number of separate mechanical
elements on the drum.
[0020] With the device described hereinabove, it also becomes possible to readily modify
the knitting program, by simply setting a different program with the aid of the random
access memories 23,24 and keyboard 29, whereas a conventional machine would require
that a large number of cams be replaced on the drum, which is a critical and time-consuming
operation.
[0021] It will be appreciated from the foregoing that the inventive device can bring about
a considerable reduction in the drum bulk. In fact,' this device requires no space
availability around the drum periphery, and the electronics can be easily enclosed
in a case or box of small dimensions, which can be mounted at any convenient location
on the machine.
[0022] Of course, the mechanical programming member which cooperates with the detecting
means may be other than the machine main drum, and be, for example, the machine main
chain.
[0023] This device, as described in the foregoing, is obviously equally applicable on single
cylinder machines and double cylinder or cylinder and dial machines.
1. A yarn feeding finger control device for a circular knitting machine, in particular
a single cylinder hose knitting machine, comprising a plurality of yarn feeding fingers
(2) pivoted individually to a stationary structure (4) of the machine and selectively
movable between a rest position whereat one yarn guiding end (2a) thereof is moved
away from the needles (7) and the respective yarn (6) is not picked up thereby, and
an operative position whereat said..end (2a) is moved closer to the needles (7) and
the yarn (6) is picked up thereby, the selective movement being accomplished by program
controlled means, characterized in that with the yarn feeding fingers (2) there are
associated respective electromagnets (11) for moving the yarn feeding fingers (2),
and that a means (13) is provided for detecting the movement of a mechanical programming
member (14) of the machine, as well as a memory device (15) electrically connected
to said detecting means (13) and.driven thereby to selectively energize and de-energize
individual electromagnets (11) in accordance with the advancing movement of said mechanical
programming member (14) of the machine.
2. A device according to Claim 1, characterized in that said mechanical programming
member. (14) is the machine main drum, and that said detecting means (13) comprise.s
a photoelectric unit (19) adapted for supplying electric pulses to said memory device
(15) at each advancing step of said drum (14), the memory device (15) being effective
to selectively and sequentially control the energization and de-energization of individual
electromagnets (11) in accordance with the pulse sequence from said photoelectric
unit (19).
3. A device according to Claims 1 and/or 2, characterized in that said detecting means
(13) comprises a disk (17) rotatively rigid with said drum (14) on one side thereof
and formed with a plurality of peripheral notches (18), and a pair of photoelements
arranged to be stationary with respect to said disk (17).
4. A device according to Claim 3, characterized in that several notches (18) are provided
for each advancing step of said drum (14).
5. A device according to one or more of the preceding claims, characterized in that
the yarn feeding fingers (2) arranged alongside a center yarn feeding finger (2) have
control ends -( 2b), opposedly located to the yarn guiding ends (2a), arranged on
further outboard planes, different from the planes of movement of the respective yarn
feeding fingers (2), and that said electromagnets (11) are staggered in several rows.
6. A device according to one or more of the preceding claims, characterized in that
said electromagnets (11) are provided with rod armatures (12) effective to apply a
thrust action on said yarn feeding fingers (2).
7. A yarn feeding finger control device for a circular knitting machine, in particular
a single 3 cylinder hose knitting machine, substantially as 4 herein described and
illustrated.