GB1561759A

GB1561759A - Processing of leather

Info

Publication number: GB1561759A
Application number: GB49110/76A
Authority: GB
Original assignee: Maschinenfabrik Turner GmbH
Current assignee: Maschinenfabrik Turner GmbH
Priority date: 1975-11-26
Filing date: 1976-11-25
Publication date: 1980-02-27
Also published as: ES453985A1; IT1064834B; FR2332943A1

Description

(54) IMPROVEMENTS IN OR RELATING TO THE PROCESSING OF LEATHER (71) We, MASCHINENFABRIK TURNER GMBH, a German Company, of 637 Oberursel/Taunus, Postfach 580, West Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention is concerned with improvements in or relating to the processing of sheet material and is especially concerned with machines for softening, stretching and glazing leather.

Leather, in the course of manufacture, is subjected to various processes to produce leather of an acceptable quality. Among the processes are those for the softening and stretching of leather: so-called staking processes. It has been proposed to effect processing of leather, for example staking, by means of two, opposed, processing tools between which the leather is through-fed and whose distance apart is increased and decreased periodically by relative movement. The operation of this so-called vibration-type staking equipment is shown in, for example, U.S. Patent Specification No. 3,398,557; in the machine shown in this U.S. specification the workpiece to be processed e.g. leather is pushed through between processing members by the operator tending the machine.

More recent work in this field has been concerned with the means by which the material to be processed is transported through the working zone of the vibration-type staking machine. It has been proposed to provide a vibration-type staking machine having processing tools with projections which interengage in the operation of the machine, in which the leather is fed through the working gap between the tools by means of two elastic conveyor belts. Such a machine is described in Patent Specification No. 1,016,191 and machines similar to that described in this specification have been used in large numbers. However, in such machines, the conveyor belts, by reason of the constant bending that extends in alternating directions throughout the whole area of the conveyor belts, are subjected to considerable strains causing rapid wear in the conveyor belts.

The invention provides, a machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, comprising two opposed processing tools, at least one of which comprises projections and the other corresponding depressions, for operating on both sides of an object simultaneously, the tools being mounted for movement around closed paths and being so arranged in relation to one another, and the paths being such, that the distance between the tools varies, as they move around their closed paths, between a condition in which the projections and depressions interengage and a condition in which the tools are spaced apart, and further the closed paths being such that, during the condition of interengagement of the projections and depressions, the tools move together along a component of forward feed movement, and during the condition when the tools are spaced apart, the tools move together along a component of return movement, the machine further comprising means for moving the tools around their closed paths with a periodic motion whereby the distance between the tools is varied periodically between said conditions so that the object is processed during the condition of interengagement of the projections and depressions and is simultaneously transported through the machine by the tools.

Preferably, the component of forward feed movement continues after the tools have moved out of the condition of interengagement of the projections and depressions. In this manner, the object, e.g.

a leather, is allowed to slide freely forwards to some extent with the velocity imparted to it by the forward movement of the tools.

During the return movement, on the other hand, the tools, being in their spaced apart condition, have practically no effect on the leather, since, due to its inertia, it continues to slide forwards as a result of the motion previously imparted by the tools thereto.

Furthermore, the higher the frequency of the periodic motion of the tools, the less is the workpiece carries back during the return movement.

Preferably each processing tool is mounted on at least one rotatable operating eccentric, means being provided for rotating the eccentrics in synchronism, thus to effect movement of the processing tools around their closed paths. If it is desired that the closed path be circular, each tool is conveniently mounted on two rotatable eccentrics, one at either end thereof.

Alternatively, the closed paths may be elliptical, in which case each tool has only one eccentric associated therewith. In the latter case, the arrangement may be such that, when the tools are in the spaced apart condition, the plane of the projections is inclined to the plane of the depressions, but when the tools are moved to their condition of inter-engagement between the projections and depressions, said planes are parallel, or substantially so. Furthermore, the arrangement may be such that the plane of the projections is furthest from the plane of the depressions at the in-feed side of the tools, thus to facilitate the admission of a leather between the tools.

For effecting movement of the tools as aforesaid, each processing tool may comprise an arm fixed to the tool and projecting therefrom adjacent the eccentric mounting, and a lever a first end portion of which is pivotally connected to the arm, arranged at an angle thereto, and a second, opposite, end portion of which is pivoted to a bearing which, in the operation of the machine, is fixed. In order to adjust the paths of the tools, however, this fixed bearing may also be adjustable. Still further, in order to adjust the amount of interengagement of the projections and depressions of the tools, the rotatable operating eccentrics themselves may each be mounted in a further eccentric, the position of which is adjustable.

In one machine in accordance with the invention, the direction of feed movement is generally horizontal. In such a machine, conveniently an elastic cover may be provided, stretched over the projections of the tool(s), but which cover is not advanced with the object to be processed during the processing thereof. The elastic cover thus provides a smooth surface on which an object to be processed can be fed.

Such an elastic cover is preferably supported at its end on rollers, whereby a new section of the cover can be introduced over said projections, e.g. as the cover wears out. Conveniently, the rollers are mounted on the tool which is provided with said cover.

Alternatively, the direction of feed movement may extend vertically, or substantially so. Furthermore, with such an arrangement, especially when the object to be processed is fed upwardly, the plane of the projections is preferably closest to the plane of the depressions at the in-feed side, i.e. the lower end, of the tools, thus to enhance the feeding action of the tools on the object to be processed.

For enhanced processing of an object, e.g. a leather, preferably both of the processing tools comprise projections which inter-engage as aforesaid in the operation of the machine, the projections on each one of said tools engaging in the depressions formed between the projections of the upper.

It will be appreciated that machines in accordance with the invention thus do not require the provision of a conveyor belt of the driven type to assist in the feeding of objects to be processed between the processing tool. It is therefore possible to select for the periodic motion of the processing tools a relatively high frequency, such as would quickly lead to the destruction of conveyor belts as provided in previous machines. For example, machines of the known type which comprise conveyor belts, may work at a frequency of approximately 10 cycles per second. A machine in accordance with the invention on the other hand, may be driven at a higher frequency, for example 20 cycles per second. This may be useful in that the length of the processing tools measured in the through-feed direction may be reduced, thus reducing their mass and calling for a substantially lighter drive and frame assembly with a resultant saving in cost.

Where the processing members are shortened as mentioned above the forces brought to bear on the leather are correspondingly reduced which leads to a smaller loading of the machine con struction.

There now follows a detail detailed description, to be read with reference to the accompanying drawings, of four staking machines in accordance with the invention hereinafter called respectively the first, second, third and fourth illustrative staking machines which machines have been selected for description to illustrate the invention merely by way of example and not of limitation of the invention.

In the accompanying drawings: Figure 1 is a diagrammatic side view partly in section showing a first illustrative staking machine; Figure 2 is a diagrammatic view showing the motion of a projection of a processing tool of the first illustrative machine; Figure 3 is a view in section of a second illustrative machine viewed from the side, with a processing gap arranged vertically; Figures 4 to 7 are diagrammatic views showing the processing tools of the second illustrative machine in four different parts of their operating cycle; Figure 8 is a diagrammatic view showing the movement paths of single projections of the processing tools of the second illustrative machine; Figure 9 is a view showing an adjusting eccentric for the selectable adjusting of the processing depth in the second illustrative machine;; Figure 10 is a view in section of a third illustrative machine with a horizontal processing gap; and Figure 11 is a diagrammatic view of part of a fourth illustrative machine showing the movement paths of single projections of the processing tools.

The first illustrative staking machine comprises two opposed, interengageable processing elements, namely processing tools 2, 3, each mounted for translational movement around a closed, circular path.

Each of the processing tools 2,3 comprises a number of projections 12 arranged so that the projections 12 of the tool 2 are in alignment with depressions between the projections 12 of the tool 3.

The first illustrative machine comprises four eccentric mechanims 13, two of the mechanisms 13 being associated with each of the processing tools 2, 3. The motion of the tools 2, 3 around their closed paths is brought about by the eccentric mechanisms 13, the mechanisms 13 associated with one of the tools 2 being rotated in the opposite direction to the eccentric mechanisms 13 associated with the other of the tools 3. The eccentric mechanisms are driven by a toothed belt 9 which passes round toothed wheels 8 of the eccentric mechanisms 13.

The belt 9 passes round a pulley 10 of a motor (not shown) by which the belt is driven to drive the eccentric mechanisms 13. The toothed belt 9 ensures that the eccentric mechanisms 13 are driven in synchronism and means are thus provided where the tools 2, 3 are moved correspondingly around their closed paths with a periodic motion.

The tools 2, 3 are mounted so that the closed paths of the tools 2, 3 overlap. As the tools are moved around their closed paths with the periodic motion, the distance apart of the tools thus periodically increases and decreases so that the projections 12 of one tool 2 interengage or mesh between the projections 12 of the other tool 3 (i.e. with the projections 12 of each tool engaged in depressions between the projections 12 of the other tool) during the phase of motion in which the paths overlap; because the tools are always moved in synchronism by the belt 9 there is no risk of the projection on one of the tools fouling the projections on the other tool.Leather 5 to be processed is processed by the processing tools 2, 3 during the phase of movement of the tools in which the paths of the tools overlap; thus the leather 5 is engaged by and worked by the projections as can be seen from Figure 1 of the drawings. During the phase in which the paths of the tools 2, 3 overlap, the tools 2, 3 also have a component of motion in the through-feed direction 18 of the first illustrative machine and thus as the tools 2, 3 process the leather 5, the leather 5 is simultaneously fed through the machine in the direction 18 by the tools. The arrows 14 indicate the direction of motion of the tool 3 around its closed path and the arrows 15 indicate the direction of motion of the tool 2 around its closed path.

The movements of a number of the projections 12 of the tools 2, 3 are shown, enlarged, in Figure 2. Two projections 12 are shown in Figure 2 (one from each of the tools 2, 3, in chain dot and dashed lines, respectively) at the position at which the tools start to interengage; the paths 4 followed by these two projections are shown, respectively, in chain dot and dashed lines and the degree of interengagement of the projections 12 is indicated by the arrow 6. The medium plane 19, between the tools 2, 3 is shown in Figure 2; the tools are interengaged when the projections 12 have passed beyond the plane 19. The distance by which the leather 5 is simultaneously transported during the cycle of movement of the tools 2, 3 is indicated by the arrow 7.

In the first illustrative machine the transporting of the leather 5 is effected by the processing tools 2, 3 themselves and this lends itself to construction of through-feed machines. In the first illustrative machine it is possible to positively influence the through-feed of the leather, for example by braking, e.g. using rolls 11, thus to obtain some relative motion between the tools and the surface of the leather in the direction 18 of the through-feed, and hence to achieve other processing effects (for example smoothing and glazing effects).

The second illustrative machine (see Figures 3 to 9) has a vertical processing gap and comprises a frame 101 on which are mounted, on supports 102, 103, bearers 104, 105 for drive-shafts 106, 107 respectively.

On the drive-shafts 106,107 are fixed, at the rear of the second illustrative machine, chain wheels 108, 109 around which is wound a drive-chain 110. The drive-chain 110 also runs over a drive chain wheel 111 of a motor 112 and a guide-sprocket 113, whereby by a corresponding looping around the chain-wheels 108, 109 it is ensured that the drive-shafts 106, 107 rotate in opposite directions. The drive-chain 110 is thereby moved as indicated by the arrows thereon.

The direction of rotation of the drive-shafts 106, 107 is likewise indicated by arrows.

On the drive-shafts 106, 107 are also seated operating eccentrics 114, 115 which are secured against rotation in relation to the drive-shafts 106, 107 by means of keys 116, 117. The operating eccentrics 114, 115 rotate in corresponding bearings (not shown in detail) in support blocks 118, 119 for the processing tools 92, 93; these bearings can be either slide-bearings or roller-bearings.

With the rotation of the drive-shafts 106, 107, the processing tools 92, 93 execute, correspondingly to the function of the eccentrices 114, 115, both a to-and-fro movement, towards and away from each other, besides moving up and down in the sense of an advance-and-return movement.

These two directions of movement naturally superimpose themselves upon each other.

In this, it is postulated that the inner side of the processing tools 92, 93 remain with projections 120, 136, 154, 121, 137, 155 thereof, facing each other, thus being held substantially parallel to each other. This requirement is here met by arms 122, 123 depending from each support block 118, 119 and by levers 124, 125 arranged at an angle thereto, the levers 124, 125 being rotatably articulated to their associated arms 122, 123 through pivot pins 126, 127. The levers 124, 125 are mounted with end portions remote from the arms 122, 123 on pivot bearings 128, 129. The pivot bearings 128, 129 are fitted rigidly, but adjustably, to the supports 102, 103. Details will be given below about the effects of an adjustment of the pivot-bearings 128, 129.The adjustability is here obtained in that the pivot-bearings 128, 129 are secured through bolts 130 which, after being loosened, make possible the interposition of inserts (not shown) by which the pivot-bearings 128, 129 can be either raised or lowered in relation to the position of their point of rotation.

Before the cycle of movement of the processing tools 118, 119 is discussed in more detail, it might be first explained how the workpiece, in this case leather, is fed through the device. As shown in the drawings, a piece of leather 131 is guided from above over a feed table 132 into a processing-gap 133, shown in Figure 3 in vertical arrangement, between the processing tools 92, 93, until, due to the furtherance effected by the latter, as described below, it issues from their outlet-end; here it is received by a chute 134 and passed on. Instead of the chute 134, a conveyor-belt 135, shown in broken lines, can also be provided to carry off the processed leather in the opposite direction.

The movement of the processing tools 92, 93 resulting from their special mounting, is hereinafter explained by reference to Figures 4 to 7.

In Figure 4 the open position of the processing tools 92, 93 is shown in which the operating eccentrics 114, 115 by their corresponding position, have brought the processing tools 92, 93 into the extreme position of withdrawal from each other. In this position, the keys 116, 117 are pointing away from the processing-gap 133. The latter is thereby opened upwards in a slight wedge-shape, so that in this position the leather can easily be guided into the processing-gap 133 from above.

Figure 5 shows the next operating-phase in which the drive-shafts 106, 107 and with them the operating eccentrics 114, 115, are rotated about 900 into a position in which the keys 116, 117 have moved upward. With this rotation of the operating eccentrics 114, 115, the processing tools 92, 93 execute a substantially upwards movement as return-movement and a forward-movement in the direction of the other processingmember, whereby the levers 124, 125 and pins 126, 127 are displayed slightly upwards.

The arms 122, 123 thereby execute a slight pivoting movement outwards, whereby the processing-gap 133 approaches the parallel position of the processing tools 92, 93.

Figure 6 shows the next operating-phase, in which the drive-shafts 106, 107 have rotated about a further, quarter-revolution, together with the operating eccentrics 114, 115. In this position, the operating eccentrics 114, 115 have pushed the processing tools 92, 93 into their foremost position, in which the projections thereof are thus most deeply interengaged. The processing tools 92, 93 are also parallel to each other.

The following operating-position, represented in Figure 7, shows the drive-shafts 106, 107, together with the operating eccentrics 114, 115, rotated about a further quarter revolution in which the keys 116, 117 are pointing downwards. In this position, the processing tools 92, 93 are again moved a certain distance away from each other, owing to the effect of the eccentrics, and thereby also displaced downwards, whereby the processing-gap 133 between the processing tools is again opened in a slight wedge-shape. In the movements of the processing tools 92, 93 from the operating phase shown in Figure 5 to the operating phase according to Figure 7, the levers 124, 125 execute a pivoting movement downwards, as the processing tools 92, 93 are moved downwards by the eccentrics 114, 115.In this pivoting of the levers 124, 125, the arms 122, 123 rotate outwards relatively to the eccentrics 114, 115, so that the parallel position of the processing tools 92, 93, as shown in Figure 6 occurs. When, then, the processing tools 92, 93 are displaced further downwards by further rotation of the eccentrics 114, 115 and again drawn apart from each other, the levers 124, 125 likewise swing downwards but exert a certain amount of pressure on the arms 122, 123 by the separating action of the processing tools 92, 93, so that the arms 122, 123 are swung inwards, from which the slight wedge-shape of the processing-gap 133 as shown in Figure 7, arises.

In Figure 8 the sequence of movement of projections 120/121, 154/155 and 136/137 are represented. The projections 136/137 are situated at the inlet end of the processing tools 92, 93 of the second illustrative machine, the projections 154/155 somewhat below the middle and the projections 120/121 at the outlet end of the processing tools 92, 93. The ellipses depicted in connection with a projection represent the path of movement of a specified point on the relevant projection.

Thus a point 138 on the projection 137 describes an ellipse 139. Points 138 on the further projections 136, 154, 155, 120 and 121 likewise describe ellipses. Figure 8 plainly shows that the ellipses, from above downwards in the through-feed direction, progressively conform more and more to the vertical with their longest axes, and increasingly overlap a median plane 140 between the processing members 92, 93.

The overlapping of median plane 140 by the ellipses indicates that the processing tools engage in each other to a corresponding depth and length. It can also be seen from Figure 8 that the section of ellipse overlapping in each case the median plane 140 increases from the top downwards, thus in the through-feed direction, which signifies that the workpiece is processed for a correspondingly increasing duration by the relevant projections. From this arises the effect, referred to previously, of an increase in processing intensity in the through-feed direction.

In Figure 9 the support block 118 of the processing tool 92 is shown by which, by an adjustable eccentric 150, a selectable adjustment of the processing depth is made possible. In practical terms, the adjustable eccentric 150 represents the outer bearing for the operating eccentric 114. By the rotation of the adjustable eccentric 150, the operating eccentric 114 assumes a specific position relatively to the processing tool 92, this position being determined by the amount of rotation of the adjustable eccentric 150. The adjustable eccentric 150 is held fixed in relation to the processing tool 92 by an adjusting screw 151. For the different adjustments of the adjustable eccentric 150, a number of bores 152 are provided. In the position of the adjustable eccentric 150 shown, the processing tool 92 is adjusted for its greatest depth of engagement.

It can be seen from Figures 4 to 7 that the processing tools 92, 93 continually travel downwards, in relation to the broken reference line above the Figures, from the position shown in Figures 5 to the one in Figure 7; the distance of the reference line from the frame 101 of the second illustrative machine remains constant. The increasing distance of the inlet edge portions of the processing tools 92, 93 from the reference line on the way through the working phases according to Figures 5 to 7 shows that over these processing phases a piece of leather held by the processing tools 92, 93 is carried downwards with them: a forward-feed movement is thus imparted to the leather.

When the processing phase according to Figure 7 commences, in which the processing tools 92, 93 again move away from each other and execute the return movement which consists of the path through the processing phases according to Figures 7, 4 and 5, the leather then remains, relatively to the frame 101 of the second illustrative machine, in substantially the position that it has reached, since it is prevented by its inertia from participating in the return movement. Moreover, according to the law of inertia, it actually tends to follow its previously enforced forward feed movement. In addition, there is also the force of gravity which further helps the downward movement of the leather.

The third illustrative machine shown in Figure 10 has a horizontally situated processing-gap 141. Apart from the arrangement of the third illustrative machine with its processing-gap horizontal, the construction and arrangement of the third illustrative machine is identical with that of the second illustrative machine except as hereinbefore described and like numbers are therefore used to represent like parts, where appropriate. Analogously to the arrangement of the pivot bearings 128, 129 shown in Figures 3 to 9, in the third illustrative machine pivot bearings 142 are arranged aft of operating eccentrics 143 in the forward feed direction, this direction being indicated by arrow A pointing towards the processing-gap 141.By this arrangement of the pivot bearings 142 the desired effect is produced in that on the inlet side the processing-gap 141 opens wider than on the outlet side (see the corresponding representation in Figure 4).

In order that the projections 120, 121 do not form an obstacle for the edge of the workpiece when the latter is being inserted into the processing-gap 141, flexible covers 144 and 145 are stretched over the projections 120, 121 of the processing tools 92, 93, the covers 144 and 145 consisting, for example, of an elastic foil. In the situation depicted in Figure 10 of the processing members 92, 93, in which they are drawn apart, out of engagement with each other, the covers 144, 145 stretch in such a way over the projections 120, 121 that they present substantially flat surfaces so that the workpiece -- leather 131 - can be pushed without hindrance into the processing-gap 141. The covers 144, 145 end on both sides of the processing members 92, 93 at rollers 146, 147, 148, 149.The covers 144, 145 are held stationary during the operating of the third illustrative machine. If a cover becomes damaged by the operating of the third illustrative machine, one needs only to wind it from one roller on to the other until a complete, undamaged section of the cover stretches over the relevant processing tool.

In this, practically no interruption of the operating of the third illustrative machine is required.

If one now applies the same considerations to the third illustrative machine shown in Figure 10 as applied above in relation to the second illustrative machine the same forward feed effect can be seen to occur. The leather is pushed in the direction of the arrow A during the coming together of the processing tools 92, 93, until it is again released from them. They then execute the return movement, as described above. By reason of its inertia, the leather does not participate in this return movement. This effect is further enhanced by the covers 144, 145 stretched over the projections 120, 121, as the smooth surface of the covers does not give rise to any significant friction upon the leather on the return movement of the processing tools 92, 93.There thus occurs in the third illustrative machine, with a horizontal processing-gap 141, an automatic forward feed effect without any need of conveyor belts for the purpose, whereby the forward feed effect is caused solely by the movement of the processing tools 92, 93, which, as has been said, execute not only an up-and-down movement but also a to-and-fro movement.

The fourth illustrative machine (Figure 11) has much in common with the second and third illustrative machines in that it comprises two processing tools 192, 193 each mounted on an operating eccentric and maintained with their surfaces substantially parallel by an arm and lever system, and reference is directed to the description of the second and third illustrative machines for those aspects of the fourth illustrative machine not described in detail hereinafter.

The processing elements 192, 193 of the fourth illustrative machine comprise projections of which, in Figure 11, only projections 220/221 and 236/237 are shown.

In Figure 11 the drive means of the processing tool 192 only, is shown. The processing tool 192 is mounted on an operating eccentric 214 which is secured by means of a key 216 on a drive shaft 206.

From the bearing in which the eccentric 214 rotates, an arm 222 projects on which a lever 224, arranged at an angle thereto, is pivoted, the opposite end of the lever 224 being pivoted on a stationary pivot bearing 228. Ellipses 241/242 and 247/248 represent the movement of a particular point of the respective one of the projections 220/221 and 236/237. The point 243 on the projection 220 passes around the ellipse' 241; likewise point 244, 245, 246 on the projections 221, 236, 237 pass around the corresponding ellipses 242,247 and 248. The shaded parts of the ellipses 241/242 and 247/248 show where these ellipses pass across the median plane 240 between the tools 192, 193 of the fourth illustrative machine.The overlapping of the median plane 240 by the ellipses indicates that the projection 220, 221, 236, 237 intermesh or interengage with one another for a corresponding depth and over a corresponding distance.

As can be seen from Figure 11 the ellipses 241, 242 lie flatter in relation to the median plane 240 than the ellipses 247, 248 (the major axes of the ellipses 241, 242 being more nearly parallel to the median plane 240 than the major axes of the ellipses 247, 248.) The arrow B indicates the direction of rotation of the eccentric 214 and the arrows on the ellipses indicate the direction in which the points move around the associated ellipses. It can be seen that the ellipses 241, 242 cut the median plane 240 (when travelling around that part of the ellipse bounding the shaded area) at a smaller acute angle than the ellipses 247, 248. The intersection points of the ellipses 241, 242 with the median plane 240 are indicated as 249, 250 and the intersection points of the ellipses 247,248 are indicated as 251, 252. The more acute the angle of intersection, the greater the component of movement in the through-feed direction as the processing tools move around their closed path, and the greater is the rate of feed of the leather to be processed through the fourth illustrative machine.

The acute angled intersection of the ellipses with the median plane 240, as previously described, has a result that the processing tools 192, 193 are moved into the opened position (with their respective projections 220, 221, 236, 237 out of engagement) whilst the projections are still travelling with a component of movement in the through-feed direction. So that as a result, after passing through the points 249, 250, 251, 252 the kinetic energy given to the workpiece during interengagement is still effective in carrying the workpiece forward in the through-feed directions because, after passing through the points 249, 250, 251, 252 the processing tools 192, 193 have released the workpiece so that it can slide forward between the tools further in the direction of feed due to the kinetic energy given to it.

Since, as mentioned above, the ellipses 241, 242 cut the median plane at a more acute angle than the ellipses 247, 248, the kinetic energy imparted to the workpiece by the processing tools 192, 193 is greater in the region of the projections 220, 221 than in the region of the projections 236, 237; this can make it expedient to feed the workpiece into the fourth illustrative machine from the region of the projections 220, 221 as it is then drawn in from this side more intensively than it is fed at the side 236, 237.

To accomplish this the pivot bearing 228 is (as can be seen in Figure 11) mounted in the fourth illustrative machine at the inlet side of the machine (i.e. at that side of the machine at which the projections 220, 221 are disposed). This is in contrast with the case in respect of the second and third illustrative machines in which the pivot bearings are disposed at the outlet side of the machines. The direction (indicated by the arrow C) of feed of the workpiece shown in Figure 11 in respect of the fourth illustrative machine is believed to be especially important when processing in leather. In the fourth illustrative machine the processing tools 192, 193 can be arranged so that the median line 240 is vertical, horizontal or diagonal.

Each of the illustrative machines is a through-feed machine in which conveying take place automatically and, moreover, in which the use of conveyor belts is avoided.

Transport of an object to be processed is thus achieved by means which has not hitherto been used in machines for processing flat, flexible objects using oscillating processing tools. Thus the oscillating tools in the illustrative machines not only have the function of processing but also simultaneously carry out the transporting function, and conveying belts are thus not required. Hitherto, oscillating tools have executed movements on a straight or nearly straight path; in such machines an additional feed organ is required which may be conveyor belts or may be the operator tending the machine.

In the illustrative machines each tool executes a periodic motion around an associated closed path with which motion it is possible simultaneously to process the leather (with the overlapping of the paths of the two tools) and to transport it by the component of the motion of the tools which is in the direction of transport.

WHAT WE CLAIM IS: 1. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, comprising two opposed processing tools, at least one of which comprises projections and the other corresponding depressions, for operating on both sides of an object simultaneously, the tools being mounted for movement around closed paths and being so arranged in relation to one another, and the paths being such, that the distance between the tools varies, as they move around their closed paths, between a condition in which the projections and depressions interengage and a condition in which the tools are spaced apart, and further the closed paths being such that, during the condition of interengagement of the projections and depressions, the tools move together along a component of forward feed movement, and during the condition when the tools are spaced apart, the tools move together along a component of return movement, the machine further comprising means for moving the tools around their closed paths with a periodic motion whereby the distance between the - tools is varied periodically between said conditions so that the object is processed during the condition of interengagement of the projections and depressions and is simultaneously transported through the machine by the tools.

2. A machine according to Claim 1 wherein the component of forward feed movement continues after the tools have moved out of the condition of interengagement of the projections and depressions.

3. A machine according to either one of Claims 1 and 2 wherein each processing tool is mounted on a rotatable operating eccentric and means is provided for rotating the eccentric in synchronism and thus to effect movement of the processing tools around their closed paths.

4. A machine according to any one of the preceding Claims wherein, when the tools are in the spaced apart condition, the plane of the projections is inclined to the plane of the depressions, but when the tools are moved to their condition of interengage-

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the fourth illustrative machine. The acute angled intersection of the ellipses with the median plane 240, as previously described, has a result that the processing tools 192, 193 are moved into the opened position (with their respective projections 220, 221, 236, 237 out of engagement) whilst the projections are still travelling with a component of movement in the through-feed direction. So that as a result, after passing through the points 249, 250, 251, 252 the kinetic energy given to the workpiece during interengagement is still effective in carrying the workpiece forward in the through-feed directions because, after passing through the points 249, 250, 251, 252 the processing tools 192, 193 have released the workpiece so that it can slide forward between the tools further in the direction of feed due to the kinetic energy given to it. Since, as mentioned above, the ellipses 241, 242 cut the median plane at a more acute angle than the ellipses 247, 248, the kinetic energy imparted to the workpiece by the processing tools 192, 193 is greater in the region of the projections 220, 221 than in the region of the projections 236, 237; this can make it expedient to feed the workpiece into the fourth illustrative machine from the region of the projections 220, 221 as it is then drawn in from this side more intensively than it is fed at the side 236, 237. To accomplish this the pivot bearing 228 is (as can be seen in Figure 11) mounted in the fourth illustrative machine at the inlet side of the machine (i.e. at that side of the machine at which the projections 220, 221 are disposed). This is in contrast with the case in respect of the second and third illustrative machines in which the pivot bearings are disposed at the outlet side of the machines. The direction (indicated by the arrow C) of feed of the workpiece shown in Figure 11 in respect of the fourth illustrative machine is believed to be especially important when processing in leather. In the fourth illustrative machine the processing tools 192, 193 can be arranged so that the median line 240 is vertical, horizontal or diagonal. Each of the illustrative machines is a through-feed machine in which conveying take place automatically and, moreover, in which the use of conveyor belts is avoided. Transport of an object to be processed is thus achieved by means which has not hitherto been used in machines for processing flat, flexible objects using oscillating processing tools. Thus the oscillating tools in the illustrative machines not only have the function of processing but also simultaneously carry out the transporting function, and conveying belts are thus not required. Hitherto, oscillating tools have executed movements on a straight or nearly straight path; in such machines an additional feed organ is required which may be conveyor belts or may be the operator tending the machine. In the illustrative machines each tool executes a periodic motion around an associated closed path with which motion it is possible simultaneously to process the leather (with the overlapping of the paths of the two tools) and to transport it by the component of the motion of the tools which is in the direction of transport. WHAT WE CLAIM IS:

1. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, comprising two opposed processing tools, at least one of which comprises projections and the other corresponding depressions, for operating on both sides of an object simultaneously, the tools being mounted for movement around closed paths and being so arranged in relation to one another, and the paths being such, that the distance between the tools varies, as they move around their closed paths, between a condition in which the projections and depressions interengage and a condition in which the tools are spaced apart, and further the closed paths being such that, during the condition of interengagement of the projections and depressions, the tools move together along a component of forward feed movement, and during the condition when the tools are spaced apart, the tools move together along a component of return movement, the machine further comprising means for moving the tools around their closed paths with a periodic motion whereby the distance between the - tools is varied periodically between said conditions so that the object is processed during the condition of interengagement of the projections and depressions and is simultaneously transported through the machine by the tools.

ment between the projections and depressions, said planes are parallel, or substantially so.

5. A machine according to Claim 4 when tied to Claim 3 wherein each processing tool comprises an arm fixed to the tool and a lever a first end portion of which is pivotally connected to the arm and a second, opposite, end portion of which is pivoted to a fixed bearing.

6. A machine according to Claim 5 wherein the fixed bearing is adjustable, thus to adjust the paths of the tools.

7. A machine according to any one of Claims 3, 5 and 6 or to Claim 4 when tied to Claim 3 wherein the rotatable operating eccentric is itself mounted in a further eccentric the position of which is adjustable, whereby to adjust the amount of interengagement of the projections and depressions of the tools.

8. A machine according to any one of Claims 4 to 6 wherein the plane of the projections is furthest from the plane of the depressions at the in-feed side of the tools.

9. A machine according to any one of the preceding Claims wherein the direction of feed movement is generally horizontal.

10. A machine according to any one of the preceding Claims wherein an elastic cover is provided, stretched over the projections of the tool(s), but which cover is not advanced with the object to be processed during the processing thereof.

11. A machine according to Claim 10 wherein the elastic cover is supported at its ends on rollers, whereby a new section of the cover can be introduced over said projections.

12. A machine according to Claim 11 wherein the rollers are mounted on the tool provided with said cover.

13. A machine according to any one of Claims 1 to 8 wherein the direction of feed movement extends vertically, or substantially so.

14. A machine according to any one of Claims 4 to 6 wherein the plane of the projections is closest to the plane of the depressions at the in-feed side of the tools, and further wherein the direction of feed movement extends vertically, or substan tially so, upwardly.

15. A machine according to any one of the preceding Claims wherein both tools comprise projections which inter-engage as aforesaid in the operation of the machine, the projections on each one of said tools engaging in the depressions formed between the projections of the other.

16. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

17. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to Figures 3 to 9 of the accompanying drawings.

18. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, constructed arranged and adapted to operate substantially as hereinbefore described with reference to Figure 10 of the accompanying drawings.

19. A machine for the processing of flat flexible objects, especially for softening, stretching and glazing leather, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to Figure 11 of the accompanying drawings.