EP0553734A1

EP0553734A1 - Pincer assembly

Info

Publication number: EP0553734A1
Application number: EP93101013A
Authority: EP
Inventors: Gerhard Giebel; Manfred Broening; Rudi Fichtner
Original assignee: DVSG Patentverwaltungs GmbH; DVSG Engineering und Patentverwaltungs GmbH; British United Shoe Machinery Ltd
Current assignee: DVSG Engineering und Patentverwaltungs GmbH; Noxet UK Ltd
Priority date: 1992-01-25
Filing date: 1993-01-22
Publication date: 1993-08-04
Also published as: CZ6593A3; BR9300169A; GB9201659D0

Abstract

A pincer assembly for use in a pulling over and toe lasting machine is so constructed and arranged that, using a single actuator (70), the jaws (58,60) are closed under a "slipping grip" pressure, and thereafter full gripping pressure is applied, and at the same time the jaws are pivoted bodily as a unit about a common pivot (56) from a position in which they project into the path of inwiping movement of wiper plates (28) to a position in which they no longer so project.

Description

This invention is concerned with a pincer assembly for use in a pulling over and lasting machine, and with a pulling over and lasting machine comprising one or more such assemblies.
Pincer assemblies for use in pulling over and lasting machines conventionally comprise a housing, two jaws mounted on the housing at least one of which is mounted for pivotal movement about a pivot, the jaws being normally held with shoe upper-engaging surfaces thereof in an open condition and being normally held in a position for receiving a lasting marginal portion of a shoe upper to be lasted therebetween. Moreover, actuator means is conventionally provided for effecting closing of the jaws, thus to cause a lasting marginal portion of a shoe upper to be gripped therebetween, and the pressure applied to such lasting marginal portion may be varied between a reduced so-called "slipping grip" pressure and a full gripping pressure according to the different requirements perceived for the particular shoe upper by the operator.
It will be appreciated that in a conventional pulling over and lasting machine there is only a restricted space for accommodating the pincer assemblies and as a consequence there is a requirement for compactness in the design and construction of a pincer assembly. At the same time, however, it is necessary to provide the necessary motor means for closing the jaws and/or controlling the applied gripping pressure as well as motor means for effecting heightwise movement of the assemblies bodily. Moreover it is sometimes desired to cause the pincer assemblies, after a lasting marginal portion of a shoe upper has been gripped thereby, to be moved transversely of their housing and downwardly relative thereto. By such transverse and downward movement, it will be appreciated, a shoe upper gripped by the pincer assembly will, when said assembly is in use in a pulling and lasting machine, be drawn inwardly and downwardly thus to cause the upper to be "wrapped" around its last. One such pincer assembly is described, for example, in EP-A 0 364 552. In this case, however, it will be appreciated, for effecting the transverse and downward movement of the jaws of the pincer assembly additional means is required leading to a relatively bulky construction with consequent demands upon the relatively restricted space available.
It is thus one of the objects of the present invention to provide an improved pincer assembly for use in a pulling over and lasting machine, which assembly is compact and provides an improved arrangement for effecting the various movements and applying the various pressures required.
The invention thus provides, in one of its several aspects, a pincer assembly for use in a pulling over and lasting machine comprising a housing, two jaws mounted on the housing each for pivotal movement about a common pivot, said jaws being normally held with shoe upper-engaging surfaces thereof in an open condition and being normally held in a position for receiving a lasting marginal portion of a shoe upper to be lasted therebetween, and actuator means for closing the jaws, thus to cause a lasting marginal portion of a shoe upper to be gripped therebetween, by moving one of the jaws such that its shoe upper-engaging surface is moved, in a direction towards the shoe upper-engaging surface of the other jaw, such closing of the jaws being effected initially with a reduced gripping pressure and thereafter with a full gripping pressure, and also for causing the jaws as a unit to move in said direction about the common pivot, whereby a shoe upper lasting marginal portion gripped thereby can be drawn transversely of the housing and downwardly relative thereto.
It will thus be appreciated, using a pincer assembly as set out in the last preceding paragraph, using a single actuator means both the pressure applied by the jaws to a lasting marginal portion gripped therebetween can be controlled and also transverse and downward movement of the jaws relative to the housing can be effected.
In one embodiment of the invention, moreover, each jaw has an extension which extends beyond the common pivot, and the actuator means includes an actuator element which by engagement with the extensions causes closing of the jaws to effected as aforesaid. More particularly in said one embodiment, there are provided first resilient means for acting on the other of the jaws to urge it into an initial position determined by a stop, and second resilient means for urging the shoe upper-engaging surfaces of the jaws apart, and thus for urging the jaws into open condition, the position of the jaws when said other thereof is in its initial position constituting their lasting marginal portion-receiving position, the actuator element acting initially on the extension of said one of the jaws and thereafter, when the jaws are in their closed condition, on the extensions of both jaws. Moreover, the arrangement in such embodiment is such that the first resilient means controls the gripping pressure by which a shoe upper lasting marginal portion is gripped as aforesaid from the jaws reaching their closed condition until the actuator element engages and acts upon the extensions of both jaws. It will be appreciated that by the use of a single actuator means for not only the closing of the jaws but also for controlling in combination with resilient means the gripping pressure applied by the jaws to a shoe upper lasting marginal portion a compact and effective arrangement is achieved.
In one embodiment the first resilient means comprises a spring arrangement, e.g. a leaf spring arrangement, acting on the "outside" of the extension of said other of the jaws, the stop being provided on the housing. It will be appreciated that when the actuator element acts on the extension of said one of the jaws, initially the first resilient means creates a resistance to the other of the jaws moving, overcoming the influence of the second resilient means, so that the jaws are in fact closed. Moreover, while the closing force acts merely upon the extension of the one jaw, the gripping pressure applied by the jaws, when they are closed, to a lasting marginal portion placed therebetween will be determined only by the force applied by the first resilient means. Only when the actuator element engages both extensions will the gripping pressure then become controlled by the actuator means itself.
In another embodiment the first resilient means may comprise a pneumatically operated piston-and-cylinder arrangement. This, it will be appreciated, allows a greater degree of control of the closing of the jaws and also of the applied pressure and indeed preferably in this embodiment control means is also provided for controlling the supply of pressurised air to said piston-and-cylinder arrangement.
The second resilient means conveniently comprises a torsion spring arrangement, while the actuator means preferably comprises a fluid pressure-operated piston-and-cylinder arrangement a piston rod of which constitutes the actuator element.
It is a further object of the present invention to provide an improved pulling over and lasting machine in the operation of which in a simple but reliable manner collision of the wiper assembly during the inwiping movement with one or more pincer assemblies is avoided while the pincer assemblies are nevertheless positioned optimally during the initial gripping of the shoe upper lasting marginal portions.
The invention thus further provides, in another of its several aspects, a pulling over and toe lasting machine comprising a shoe support for supporting a shoe comprising a shoe upper on a last and an insole on the last bottom, a generally U-shaped array of pincer assemblies arranged around the shoe support whereby the upper of a shoe placed upon the shoe support can be gripped and tensioned about its last, and a wiper assembly movable in a plane whereby to cause a lasting marginal portion of a shoe upper gripped and tensioned as aforesaid to be wiped over and pressed against corresponding marginal portions of the insole of such shoe, characterised in that one or more of the pincer assemblies is constituted by a pincer assembly as hereinbefore set out, and in that jaws of such or each such pincer assembly, when the assembly is held in its shoe upper lasting marginal portion-receiving position, extend above the plane in which the wiper assembly is moved, but are pivoted inwardly and downwardly by the action of the actuator means prior to the inwiping movement of the wiper assembly, the shoe upper gripped thereby being thus drawn around its last.
There now follows a detailed description, to be read with reference to the accompanying drawings, of one pincer assembly in accordance with the invention and of a pulling over and lasting machine of which such pincer assembly forms part. It will of course be appreciated that this pincer assembly, and the machine of which it forms part, have been selected for description merely by way of non-limiting example.
In the accompanying drawings:-

Fig. 1 is a perspective view of a pulling over and toe lasting machine of which a pincer assembly in accordance with the invention forms part;
Fig. 2 is a fragmentary view showing details of a pincer assembly in accordance with the invention, with jaws thereof in an open condition;
Fig. 3 is a fragmentary view, generally similar to Fig. 2, but with additional details of a support for the pincer assembly, and showing the jaws in a closed condition and pivoted inwardly and downwardly; and
Fig. 4 is a view similar to Fig. 2 but showing an alternative resilient means acting on one of the jaws.

There is hereinafter described a pulling over and toe lasting machine comprising a shoe support, in the form of a toe rest 20 (Fig. 1), and a plurality of pincer assemblies 22, comprising toe and forepart pincers, arranged in a generally U-shaped array about the shoe support. In addition, the machine comprises toe lasting instrumentalities including a wiper assembly comprising two wiper plates 28, a toe pad 32 and a toe band 34. A heel rest 36 is also provided for holding the shoe in position on the toe rest 20. Furthermore, for applying adhesive to the toe and forepart regions of the shoe bottom prior to the operation of the wiper assembly 28, a so-called imprinter plate 38 is provided, which is generally U-shaped and which extends about the periphery of the toe rest. The machine further comprises a foot switch FS, which is operator-actuatable, and a control panel 26 is provided incorporating various switches for facilitating various settings of the machine.
Machines of the aforementioned type are well known, as is also their operation.
The pincer assemblies 22 are each mounted on a base plate 40 (Fig. 3), as is conventional, for adjustment independently of one another relative to the shoe support 20 according to the style of shoe being operated upon. The pincer assemblies are generally similar to one another and one such assembly will now be described with reference to Figs 2. and 3.
For supporting the pincer assembly a support 42 is mounted on the base plate 40 for adjusting movement towards and away from the shoe support 20 by a pin-and-slot connection, and a further support 44 is in turn supported by the support 42 for pivotal adjustment about an axis extending normally to the bottom of a shoe supported by the shoe support 20. Mounted in the further support 44 is a column 46 which is movable heightwise by means of a piston-and-cylinder arrangement (not shown) carried on the underside of the base plate 40. The column 46 supports a block 50 the upper end of which is bifurcated to form two wall portions, one at either side of a support surface 52. Received between the wall portions and supported on the surface 52 is a pincer housing 54 on which is provided, at its upper end, a pivot pin 56 on which two jaws 58,60 are supported for pivotal movement. Acting on the outer surface of the jaw 60 is a leaf spring 62 which is carried on the housing 54 and urges the jaw 60 clockwise (viewing Figs. 2 and 3) about the pivot 56 to the position shown in Fig. 2, which is determined by engagement of an extension 60a of the jaw 60, which extension extends beyond the pivot 56, with an abutment surface 64 provided by the housing 54. (The leaf spring arrangement 62 constitutes first resilient means of the pincer assembly.)
The jaws 58,60 are urged apart into an open condition by a torsion spring 66 which is carried on the pivot 56. (The torsion spring arrangement 66 constitutes second resilient means of the pincer assembly.) It will thus be appreciated that, by the composite action of the leaf spring 62 and the torsion spring 66 the normal or rest position of the jaws 58,60 is as shown in Fig. 2, with the jaws held in open condition. Moreover, in this position, it can be observed, at least one of the jaws extends above a plane P in which the wiper plates 28 move.
The pincer assembly also comprises actuator means generally designated 68 and comprising a piston-and-cylinder arrangement 70 mounted on the pincer housing 54 and having a piston rod 72 mounted for sliding movement in the housing 54. At its upper end the piston rod 72 carries a roller 76 which engages with an inclined lower end face of an extension 58a of the jaw 58, which extension also extends beyond the pivot 56. When the piston-and-cylinder arrangement 70 is operated, the roller 76 is moved in a direction towards the common pivot 56 and in so doing runs along the end face of the extension 58a with a result that the jaw 58 is caused to pivot anticlockwise (viewing Figs. 2 and 3) about the pivot 56 and thus the jaws are moved to their closed condition. It will be noted that the relative forces applied by the leaf spring arrangement 62 and the torsion spring arrangement 66 are such that the force applied by the torsion spring is overcome first when the arrangement 70 is actuated, thereby causing the jaws to close. Moreover, when the jaws have reached their closed condition, initially the gripping pressure applied by the jaws to a lasting marginal portion of a shoe upper gripped therebetween will be controlled by the leaf spring arrangement 62, as the jaws 58,60 as a unit are now caused to pivot about the common pivot 56 against the influence of the leaf spring arrangement.
Continued advancing movement of the piston rod 72 ultimately brings the roller 76 into engagement with the extensions 58a, 60a of both jaws (see Fig. 3) whereupon the gripping pressure applied by the jaws to a lasting marginal portion as aforesaid is transferred to the control of the piston-and-cylinder arrangement 70. It will also be observed by comparison of Figs. 2 and 3 that by reason of the shape of the extensions 58a, 60a of the jaws, and in particular the shape of the surfaces engaged by the roller 76, and by reason of the angled location of the actuator means, in closing the jaws and in thereafter applying full gripping pressure the jaws are pivoted out of the plane P so that the risk of collision between the jaws and inwardly moving wiper plates 28 is reliably avoided. Moreover, by the pivoting of the jaws about the pivot 56 the jaws are moved transversely of the housing 54, and thus inwardly relative to the shoe support 10, whereby the shoe upper gripped thereby tends to be "wrapped" around its last during the tensioning action.
When the upper has been gripped and tensioned as described above, the pulling over and lasting operation then continues in a conventional manner, e.g. as described in EP-A 0 364 552; that is to say the operator can adjust the position of the upper by discretionary pulling using levers 30 (Fig. 1), the toe band and toe pad are applied and the wiper plates 28 begin their inward movement firstly to trap the lasting marginal portions of the upper against the insole shoe, the jaws 58,60 of the pincers being released during such inward movement of the wiper assembly and in timed relation therewith thus to ensure that the tension in the upper is maintained. Following the application of adhesive by the imprinter 38, furthermore, the inward movement of the wiper assembly is continued thus to wipe the lasting marginal portions of the upper over and press them against corresponding marginal portions of the insole to which adhesive has been applied. Bedding pressure is then applied between the wiper assembly 28 and the toe pad 32 in the usual manner.
In Fig. 4 is shown an alternative form of pincer assembly, which is generally similar to the pincer assembly described above, differing therefrom only in that the leaf spring arrangement 62 is replaced by a pneumatically operated piston-and-cylinder arrangement 80 having a plunger 82 which engages with the inner surface of the extension 60a of the jaw 60. The arrangement 80 is formed integral with the housing 54.
The piston-and-cylinder arrangement 80 may provide merely the same function as the leaf spring, namely of applying a constant resilient pressure to the jaw 60 to maintain it in position as determined by the stop 64. Alternatively, however, by using a piston-and-cylinder arrangement it is possible to vary the force applied by it not only in relation to the force applied by the actuator means 68 but also the force applied by the torsion spring arrangement 66. By varying the force applied by the piston-and-cylinder arrangement 80 during an operating cycle, the sequence in which the jaws 58,60 pivot inwardly and are moved to their closed condition under the action of the actuator means 68 can be varied also. For example, it may be desired to effect a certain amount of pivotal movement prior to the closing of the jaws 58,60 and this can be achieved by applying an initial low pressure to the arrangement 80, such that the force applied by the torsion spring arrangement 66 is greater, and thereafter at a given time increasing the force to arrest the movement of the jaw 60 and allow the jaw 58 to close on it. To this end, any suitable control means may be provided for regulating the pressure of fluid supplied to the piston-and-cylinder arrangement 80. Such control means may be mechanically operated regulator valves, dependent upon the amount of movement of, say, the piston rod 72, or the control means may be electronic.

Claims

A pincer assembly for use in a pulling over and lasting machine characterised by
a housing (54),
two jaws (58,60) mounted on the housing (54) each for pivotal movement about a common pivot (56), said jaws (58,60) being normally held with shoe upper-engaging surfaces thereof in an open condition and being normally held in a position for receiving a lasting marginal portion of a shoe upper to be lasted therebetween, and
actuator means (68) for closing the jaws (58,60), thus to cause a lasting marginal portion of a shoe upper to be gripped therebetween, by moving one (58) of the jaws (58,60) such that its shoe upper-engaging surface is moved in a direction towards the shoe upper-engaging surface of the other jaw (60), such closing of the jaws (58,60) being effected initially with a reduced gripping pressure and thereafter with a full gripping pressure, and also for causing the jaws (58,60) as a unit to move in said direction about the common pivot (56), whereby a shoe upper lasting marginal portion gripped thereby can be drawn transversely of the housing (54) and downward relative thereto.
A pincer assembly according to Claim 1 characterised in that each jaw (58,60) has an extension (58a,60a) which extends beyond the common pivot (56), and in that the actuator means (68) includes an actuator element (76) which by engagement with the extensions (58a,60a) causes closing of the jaws (58,60) to be effected as aforesaid.
A pincer assembly according to Claim 2 further characterised by
first resilient means (62; 80,82) for acting on the other (60) of the jaws (58,60) to urge it (60) into an initial position determined by a stop (64), and
second resilient means (66) for urging the shoe upper-engaging surfaces of the jaws (58,60) apart, and thus for urging the jaws (58,60) into open condition, the position of the jaws (58,60) when said other (60) thereof is in its initial position constituting their lasting marginal portion-receiving position,
and characterised in that the actuator element (76) acts initially on the extension (58a) of said one (58) of the jaws (58,60) and thereafter, where the jaws (58,60) are in their closed condition, on the extensions (58a,60a) of both the jaws (58,60).
A pincer assembly according to Claim 3 characterised in that the first resilient means (62) controls the gripping pressure by which a shoe upper lasting marginal portion is gripped as aforesaid from the jaws (58,60) reaching their closed condition until the actuator element (76) engages and acts upon the extensions (58a,60a) of both jaws (58,60).
A pincer assembly according to either one of Claims 3 and 4 characterised in that the first resilient means (62) comprises a spring arrangement (62).
A pincer assembly according to either one of Claims 3 and 4 characterised in that the first resilient means (80,82) comprises a pneumatically operated piston-and-cylinder arrangement (80).
A pincer assembly according to Claim 6 further characterised by control means for controlling the supply of pressurised air to said piston-and-cylinder arrangement (80).
A pincer assembly according to any one of Claims 3 to 7 characterised in that the second resilient means (66) comprises a torsion spring arrangement (66).
A pulling over and toe lasting machine comprising
a shoe support (20) for supporting a shoe comprising a shoe upper on a last and an insole on the last bottom,
a generally U-shaped array of pincer assemblies (22) arranged around the shoe support whereby the upper of a shoe placed upon the shoe support can be gripped and tensioned about its last, and
a wiper assembly (28) movable in a plane (P) whereby to cause a lasting marginal portion of a shoe upper gripped and tensioned as aforesaid to be wiped over and pressed against corresponding marginal portions of the insole of such shoe,
characterised in that one or more of the pincer assemblies (22) is constituted by a pincer assembly according to any one of the preceding Claims,
and in that the jaws (58,60) of such or each such pincer assembly (22), when the assembly (22) is held in its shoe upper lasting marginal portion-receiving position, extend above the plane (P) in which the wiper assembly (28) is moved, but are pivoted inwardly and downwardly by the action of the actuator means (68) prior to the inwiping movement of the wiper assembly (28), the shoe upper gripped thereby being thus drawn around its last.