[0001] The present invention relates to an insertion device for rolling machines.
[0002] As is known, screws, bolts and rotational parts in general may be manufactured by
means of rolling machines with flat dies, which generate the thread by cold rolling.
[0003] In an automatic rolling machine with flat dies, the blank is placed between two plates,
one of which is motionless while the other performs a reciprocating motion, the plates
causing the blank to roll under pressure.
[0004] The plates have protrusions which are inclined with the angle that corresponds to
the pitch of the thread to be formed, they constitute a female thread which is spread
flat and, by pressing the material, force the material, by pressure, to assume the
shape of the thread.
[0005] The machine is provided with a feeder which picks up a blank that arrives from a
feed guide and arranges it between the two plates.
[0006] Generally, blank insertion systems include a component, constituted by a retention
blade, which is adapted to close the descent flow of the blanks along the guide, in
order to prevent them from entering the rolling region during the machine cycle.
[0007] Such retention blade is then opened at the appropriate time, generally by the thrust
of the blank that is pushed in turn by the insertion pusher. In other cases, a cam,
again moved by the insertion pusher, opens the blade.
[0008] In any case, the insertion cycle is then completed by the insertion pusher which
pushes the part between the dies, when it reaches its dead center toward the slider.
[0009] By varying the relative position of the dies, in the top dead center of the movable
one, the correct timing of the rolling cycle is achieved.
[0010] This adjustment is laborious due to the fact that it is necessary to move the entire
assembly of the spindle axis of the rolling machine.
[0011] DE-1935451 discloses a device for separating and aligning screw blanks in thread rolling machines,
of the above described type. Such device comprises an inserter which moves the blanks
via a guide to the tools. A separator tongue cooperates with the inserter. It is driven
separately via a separate control mechanism to operate in synchronisation with the
inserter. The control mechanism is connected with a cam which is adjusted to fix the
position and motion of the tongue.
[0012] Adjusting the cam is a rather laborious and time consuming operation.
[0013] The aim of the present invention is to provide an improved insertion device.
[0014] Within the scope of this aim, an object of the invention is to provide an insertion
device that allows quick and easy adjustment and timing of the system even during
the operation of the machine.
[0015] A further object of the invention is to provide a device wherein the adjusting does
not involve complicated mechanical operations, such as adjusting the position of a
cam or other mechanical component.
[0016] Another object of the present invention is to provide a device that can be provided
easily by using commonly commercially available elements and materials and is furthermore
competitive from an economic standpoint.
[0017] This aim and these and other objects that will become better apparent hereinafter
are achieved by an insertion device for rolling machines, as claimed in the appended
claims.
[0018] Further characteristics and advantages will become better apparent from the description
of preferred but not exclusive embodiments of the invention, illustrated by way of
non-limiting example in the accompanying drawings, wherein:
Figure 1 is a perspective view of the blank insertion region in a rolling machine
with flat dies, according to the present invention;
Figure 2 is another perspective view of the blank insertion region in a rolling machine
with flat dies, according to the present invention;
Figure 3 is a further perspective view of the blank insertion region in a rolling
machine with flat dies, according to the present invention;
Figures 4-8 are schematic views of the apparatus, illustrating the operating sequence
thereof;
Figures 9-13 are schematic use, in enlarged scale with respect to the preceding ones,
which illustrate the same operating sequence.
[0019] With the reference to the cited figures, the apparatus according to the invention,
generally designated by the reference numeral 1, generally comprises a fixed plate
2 and a reciprocating movable plate 3.
[0020] A blank 4, which arrives from a feed guide 5, is placed between the two plates 2
and 3, which make the blank roll under pressure.
[0021] The plates 2 and 3 have protrusions which are inclined with an angle that corresponds
to the pitch of the thread, thus constituting a female thread which is spread flat.
The two plates press the material and force it to assume the shape of the thread,
in a per se known manner.
[0022] According to the present invention, the system for the insertion of a blank 4 comprises
an insertion pusher 6, which conveys the blank 4 up to contact with the movable plate
3, and a stop blade 7, which retains the blank 4 prior to its insertion between the
plates.
[0023] The stop blade 7 is preferably moved by means of a linear motor 8. The insertion
pusher 6 also is moved by means of a linear motor.
[0024] The operation of the insertion system according to the present invention is shown
in Figures 4-8 and 9-13.
[0025] In the initial condition, which is visible in Figures 4 and 9, the insertion pusher
6 retains the blanks 4 by obstructing the sliding guide 5.
[0026] To begin the insertion operation, the insertion pusher 6 retracts in order to cause
a blank 4 to slide until it makes contact with the stop blade 7, as can be seen in
Figures 5 and 10.
[0027] At this point the insertion pusher 6 conveys the blank 4 into contact with the movable
plate 3, while the stop blade 7, which protrudes beyond the vertical edge of the fixed
plate 2, retains the blank 4, preventing it from entering between the plates. This
condition is visible in Figures 6 and 11, which also schematically show that the movable
plate 3 retracts slightly in order to place the blank in the desired initial point,
as shown by the circular arrow of the figures.
[0028] When the synchronization chosen by the operator by means of software and the operator
panel provides clearance, the blade is made to retract, by means of the linear motor
control 8, and simultaneously the insertion pusher 6 increases its thrust, so as to
insert the blank exactly in the desired point of the movable plate 3, at the beginning
of its longitudinal stroke. This condition is shown in Figures 7-8 and 12-13.
[0029] Figures 8 and 13 are views of the advanced rolling step, in which the stop blade
7 is by then completely retracted.
[0030] The present insertion device offers important advantages, including general ease
of adjustment and in particular ease in determining the perfect timing before and
during the working cycle simply by acting on the movement of the stop blade 7, which
is also the simplest mechanical element of the entire insertion mechanism.
[0031] The precision and constancy of the mechanism ensure total and effective control of
the process, with the best assurance of product quality.
[0032] In the insertion systems of the prior art, the insertion system is tuned by moving
the entire assembly of the spindle axis of the rolling machine, in order to achieve
the same effect of the present invention.
[0033] This invention also improves over the inserting systems provided with a separator
tongue driven separately via a separate control mechanism to operate in synchronisation
with the inserter. In fact, according to the present invention, the stop blade has
a simple linear motion which does not require cams or any complicated control mechanism
other than a linear motor.
[0034] The linear motion of the stop blade of the present invention provides for a reliable
operation that requires less frequent adjusting.
[0035] The linear motor can be directly controlled electronically thus providing an immediate
adjustment.
[0036] It is apparent how the present invention achieves the intended aim and objects, providing
a device for inserting the blank between the dies of the machine that allows easy
adjustment and timing of the apparatus by means of the control of the movement of
the stop blade.
1. An insertion device for rolling machines, comprising a fixed plate and a reciprocating
movable plate, a feed guide for a plurality of blanks to be inserted in an insertion
point between said fixed plate and said movable plate, an insertion pusher which is
adapted to convey to a blank into contact with the movable plate; the insertion device
being characterized in that it comprises a stop blade that moves linearly between at least two positions: a position
in which said blade protrudes beyond a vertical edge of said fixed plate and retains
said blank, preventing it from entering between said plates, and a retracted position,
in which said blade leaves free the rolling region between said plates.
2. The device according to claim 1, characterized in that the movement of said stop blade is controlled by actuation means which are synchronized
by electronic control with the movements of said insertion pusher and said movable
plate.
3. The device according to claim 2, characterized in that said actuation means of said stop blade is constituted by a linear motor.