Device for guiding laminar elements for processing, particularly intended for hide and synthetic material folding machines

The invention relates to a device for guiding laminar elements for processing, particularly intended for hide and synthetic material folding machines, which comprises a working element (15) having an active end (15a) engageable by contact with a laminar element (10) being processed, and supporting and drive means (11) for the working element (15) adapted to impart cyclic oscillations to the active end (15a) defining a path comprising a section (30) raised off the laminar element (10) and a section (31) of contact with that same laminar element (10), the contact section (31) extending along a predetermined feed direction of the laminar element (10).

BACKGROUND OF THE INVENTION 
This invention relates to a device for guiding laminar elements for 
processing, particularly intended for machines operative to fold up hides 
and synthetic materials, such as shoe uppers and insoles, leather 
articles. 
It is known that hides and comparable laminar elements are in many cases to 
be folded and set in the folded position to provide folded over and well 
finished edges, for example. Particularly in the shoemaking industrywidely 
used and important are folding machines referred to as "thermocement 
folding machines" which work on hides and the like, as pre-arranged with 
fleshed and thinned edges, and are operative to both spread an adequate 
adhesive and to fold over and press the edges. The hide or the like is fed 
in an upside down position under members which dispense glue drops or 
beads onto the flat areas of the overturned hide onto which the folded 
over edges are then pressed and caused to adhere. The glue employed is a 
hot-melt type and is delivered through a line which extends as far as the 
bottom end of the so-called "shoe", formed by a rigid lug which shaves by 
its end the area of the hide or the like to be glued. Beneath the hide 
being processed, and aligned to the cited shoe, there is provided a "jaw" 
or movable clamping body which moves up periodically to clamp the hide or 
the like against said shoe. With the hide released, the same is advanced 
by an advance mechanism having two oscillating elements called the "anvil" 
and "hammer" which grab intermittently the hide and pull through a 
predetermined pitch distance. As soon as said anvil and hammer leave the 
hide the latter is clamped between said shoe and jaw. The edge upturning 
is effected by first pressing the hide or the like onto a guide having the 
shape of a small block with an arcuate face facing the cited shoe. The 
guide or small block causes initial raising and bending of the edges and 
the final fold is obtained by the pressing action applied by the anvil and 
hammer, which cause the folded over edges to adhere to the dispensed glue. 
To facilitate the edge folding, especially in sharply bent areas, the 
folding machines also include severing members which subdivide the folded 
over edge into several small portions independent of one another. 
On the work surface there are also provided various photocells which sense 
the shape of the workpiece and adjust accordingly the transport speed of 
the material being processed and the distance between the various edge 
cuts, which cuts are to be made the closer the sharper is the bend in the 
workpiece. 
An essential condition to the proper operation of these machines is a 
correct position of the hide or synthetic material being processed at the 
cited small block. 
This correct position may be either achieved in a substantially manual way, 
such as under the supervision and action of an operator, or in an 
automatic way, by means of purposely provided guiding devices. 
Heretofore, manual and direct supervision of the process by an operator has 
been dominant over automatic monitoring, because the guiding devices 
provided heretofore have proved in many cases inadequate. 
By way of example mention may be made of Italian patent No. 685886, and 
corresponding U.S. Pat. No. 3088144, wherein a device for guiding hides 
and the like is described which is based on the use of an advance wheel 
which operates uninterruptedly on the material being processed. The 
technical solution just mentioned, like all those based on roller guide or 
in any case geometrically well-defined elements, have the fundamental 
drawback of operating in an inflexible manner, that is to say, by applying 
a constant action which tends to move the hide or the like in a tightly 
constrained manner. 
In this situation the guiding devices are to adjusted very accurately and 
yet they easily prove inadequate where the hides or the like being 
processed have very sharp bends or occasionally irregular shapes. 
It should be also considered that a malfunction, however occasional, of 
these guiding devices has higly harmful consequences because it not only 
requires again an action from an operator but also that the guiding 
devices themselves be deactivated and the completed work be corrected. 
This to the point that in many cases the conventional guiding devices, 
even where available, are not used and manual supervision by the operators 
is used instead. 
SUMMARY OF THE INVENTION 
In this situation the technical task underlying this invention is to 
provide a device for guiding laminar elements for processing which can 
substantially remedy the drawbacks of currently known devices. 
Within this technical task it is an important object of the invention to 
provide a particularly flexible and functional device, that is capable of 
adjusting itself to the different needs which are to be faced during the 
feeding of a laminar element into a processing zone, in particular during 
the feeding of a hide or the like into a folding machine. 
Another important object of the invention is to provide a device having a 
simple construction and reduced cost, synchronizable in an immediate 
fashion with the processing phases of the machine to which it is applied 
and also readily retrofitted to existing folding machines on the market 
which have no guiding members. The outlined technical task and specified 
objects are substantially achieved, according to the invention, by a 
device for guiding laminar elements for processing, particularly intended 
for hide and synthetic material folding machines, which is characterized 
in that it comprises: a working element having an active end engageable by 
contact with said laminar element, and supporting and drive means for said 
working element adapted to impart cyclic oscillations to said active end 
which define a path comprising a raised section, raised off said laminar 
element, and a contact section, of contact with the same laminar element, 
said contact section extending along a predetermined feed direction of 
said laminar element.

Detailed Description of the Invention 
The device according to this invention is generally designated by the 
reference numeral 1. It is applied, in FIG. 1, to a folding machine 2 
known per se, of which some operational members are shown schematically. 
Shown in particular are a working surface 3, a guide or small block 4 on 
which initial bending of the edge to be folded over takes place, a folding 
finger 5 which acts after the guide 4, a knife 6 active against an anvil 
knife 7, and a shoe 8 placed close to the guide 4 and dispensing, from its 
bottom end, a hot-melt glue for securing the upturned edge. 
A jaw 9, also known per se, is placed beneath the working surface 3 and 
moves cyclically upwards to engage a hide 10, or the like laminar element, 
against the base of the shoe 8. 
In a folding machine 2 there are also provided members for cyclically 
advancing the hide or laminar element 10 in the form of a hammer and 
underlying anvil which clamp the upturned edge and cause it to adhere to 
the glue dispensed from the shoe 8. The hammer and anvil drive the hide 10 
forward with the jaw 9, aligned to the shoe 8, disengaged from the shoe. 
The hammer and anvil are not shown because removed from the guide 4. 
The guiding device 1 according to the invention is engaged with a frame 2a 
of the folding machine 2 and comprises supporting and drive means 11 for a 
working element 15 which is oscillable and in contact with the hide 10. In 
detail, the guiding device 1 is engaged with the frame 2a through a small 
shaft 12 substantially parallel to the working surface 3 and projecting 
cantilever-fashion, after the manner of an appendage, from a plate-shaped 
holder 13, to which the entire guiding device 1 is led. The small shaft 12 
is adapted to allow the guiding device 1 to perform oscillations about the 
shaft 12 axis, substantially toward the cited hammer and anvil. The 
oscillations may be driven by members, not shown, such as cams and cam 
followers, and have the effect of assisting a concurrent movement of the 
hide 10 with that already imparted by said anvil and hammer. 
However, if the action of said anvil and hammer is found sufficient, one 
can select of not swinging the device toward said anvil and hammer and the 
oscillations of the device may be inhibited by means of stops or by 
clamping the small shaft 12. The holder 13 engages, at a location removed 
from the small shaft 12, a bar-like body 14 which extends in a transverse 
direction to the working surface 3 until it terminates with the cited 
working element, formed by a small rod 15 also lying transversely to the 
working surface 3 and terminated with an active end 15a. In the example 
shown, the active end 15a is a single pointed end. 
The small rod or working element 15 is oscillable axially against an 
elastic means 14a formed by a small compression spring housed inside the 
bar-like body 14. 
The bar-like body 14 is engaged with the holder 13 by means of a first 
swivel connection 18 defined by a tang 16 in continuation of the bar-like 
body 14 and a first pin 17 substantially perpendicular to the tang 16 and 
substantially parallel to the working surface 3. The first pin 17 is 
penetrated slidably by the tang 16 and both the tang 16 and the first pin 
17 have circular cross-sections, so as to permit of their rotation about 
respective axes. 
In particular, the axis of rotation of the first pin 17 defines, in the 
first swivel connection 18, an axis of oscillation 18a of the bar-like 
body 14, whereas the axis of the tang 16 defines a lifting and lowering 
axis of the bar-like body 14. 
Around the tang 16 a spring element 19 is wound which is formed by a 
compression spring closed between the first pin 17 and washers 20 fast 
with the tang 16. 
Between the first swivel connection 18 and the small rod 15 the bar-like 
body 14 is engaged, at a second pin 21, by a crosspiece-like body 22 which 
flanks the holder 13 at a position away therefrom and is terminated with a 
small plate 22a engaged centrally by a second swivel connection 23. The 
second swivel connection 23 has a part-spherical bulb 24 penetrated by a 
pin 25. The latter extends transversely of the small plate 22a and forms 
an eccentric or cam 29 with the second swivel connection 23. In fact, the 
pin 25 is affixed and parallel, in an offcentered position, to a drive 
shaft 26 penetrating the holder 13 and being driven by an electric motor 
32 preferably a DC motor. 
Mounted to the drive shaft 26 is a face cam 27 acting on a cam follower 28 
engaged with the crosspiece-like body 22. The cam follower 28 is a small 
wheel whose axis is substantially parallel to the main dimension of the 
crosspiece-like body 22. The cam 27 acts on the cam follower 28 against 
the elastic bias of the compression spring 19 fitted over the tang 16 of 
the bar-like body 14. 
The cam 27 and the cam 29 defined by the pin 25 and second swivel 
connection 23 impart cyclic oscillations on the active end 15a which 
define a path having a raised section 30 and a contact section 31 off/with 
the hide 10, as shown in FIGS. 3 to 7. 
The device operation will be now described with reference to the successive 
operational steps shown in FIGS. 3 to 7. As shown in FIG. 3, at the cycle 
start the bar-like body 14 is raised and vertical and the small rod 15 has 
its active end 15a raised off the hide 10 and relatively removed from the 
guide or small block 4 flanking the shoe 8. In this situation, coincident 
with that of FIG. 1, the cam follower 28 is in a fully raised position and 
the cam 29 has the pin 25 in the fully advanced position with respect to 
the bar-like body 14. As the drive shaft 26 is rotated the cam 27 will 
bring its outermost portion in the direction toward the working surface 3 
(FIG. 4) to contact the cam follower 28 and force therefore the 
crosspiece-like body 22 to oscillate as a whole around the second swivel 
connection 23 to bring the second pin 21 and bar-like body 14 to a down 
position, thereby the active end 15a will engage the hide 10. 
This downward movement of the active end 15a is performed against the 
compression spring 19, which is shown compressed in FIG. 4. The small rod 
15 is slidable in the axial direction against an elastic means, and 
accordingly, slight irregularities of the device or the hide 10 would be 
accommodated by axial movements of the small rod. Thereafter, as shown in 
FIG. 5, with the cam 27 still in contact with the cam follower 28 through 
an outermost zone in the direction toward the working surface 3, and 
therefore with the small rod 15 held down, the cam 29 will come to a 
diametrically opposed position fully away from the bar-like body 14. Thus, 
the bar-like body 14 is caused to rotate around the first swivel 
connection 18 and in particular about the axis of the first pin 17. Thanks 
to this rotation the active end 15a of the small rod 15 will move forward 
to substantially flank, and possibly move past, the shoe 8 in the 
direction toward the guide 4. 
This is the contact section 31 of the path travelled by the active end 15a, 
which contact section brings about an entrainment in its own right of the 
hide 10 in the direction toward the guide or small block 4, consistently 
with the requirements of this kind of machine. The contact of the active 
end 15a with the hide 10 is maintained at all times also on account of 
said axial mobility of the small rod 15. 
Subsequently, as shown in FIG. 6, there both occur an upward movement of 
the small rod 15 and a return movement thereof to the position of FIG. 3. 
In fact, further rotation of the cam will again bring the cam follower 28 
to the raised position and the compression spring 19 will raise once 
again, by acting on the washers 20, both the bar-like body 14 and the 
crosspiece-like body 22, also entraining the small rod 15. Simultaneously, 
the cam 29 will gradually move the pin 25 back to a forward position and 
therefore oscillate the bar-like body 14 around the first swivel 
connection 18 away from the guide 4. During this step, the raised section 
30 is completed which constitutes a return section to the original 
position. 
FIG. 7 is substantially coincident with FIG. 3 and shows the device return 
to the original position. 
It is apparent from the foregoing discussion that an important features of 
the invention is the cyclic thrusting of the active end 15a; the thrust 
phases are followed by inactive phases where the hide or the like is 
allowed to partially relax. In this situation it becomes possible to drive 
during the thrust phase particularly enhanced forward movements adjusted 
to fit the most critical situations, for example, without introducing 
important disturbance of the hide movement. In fact the same when 
unstressed can relax onto the working surface into the most appropriate 
position. 
Another important feature is the limited contact of the device with the 
hide being processed. This limited contact, being punctiform in the 
instance shown, causes the thrust from the active end 15a to impart no 
definite angular direction to the hide as may be inappropriate. The hide 
is merely pushed to a position against the working members of the machine 
and not forced out of its angular position. Therefore, it may even in this 
case adjust itself into the most appropriate angular position as defined 
by the working members engaging it. 
It should be also noted that it is very easy and immediate to either 
increase or decrease the thrust action: it is sufficient that the 
rotational speed of the electric motor 32 be increased or decreased to 
relate it to the pitch of the severing members formed by the knife 6 and 
anvil knife 7. 
As specified already, it is also possible to oscillate the device 1 about 
the axis of the small shaft 12 by introducing a parallel movement to the 
entrainment movement of the cited anvil and hammer. The invention is 
susceptible to many modifications and variations. For example, the 
assembly of the face cam 27 and cam follower 28, acting against the 
compression spring 19, may be replaced with a dual or desmodromic cam 
which allows elimination of the compression spring 19. 
The active end 15a may be provided with both a point and small teeth set 
close together to bite less deeply into the hide or the like. 
In the instance of guiding devices provided in conjunction with a folding 
machine, the electric motor 32 may be replaced with flexible mechanical 
linkages led to the motor of the folding machine and formed by belts and 
pulleys, for example.