US3692449A

US3692449A - Device for the spraying of shoe soles onto shoe shafts

Info

Publication number: US3692449A
Application number: US79006A
Authority: US
Inventors: Manfred Niklarz
Original assignee: Stubbe Maschinenfabrik GmbH
Current assignee: Stubbe Maschinenfabrik GmbH
Priority date: 1969-10-15
Filing date: 1970-10-08
Publication date: 1972-09-19
Anticipated expiration: 1989-09-19
Also published as: FR2065944A5; DE1951955A1

Abstract

The improved device disclosed herein is used for the spraying of shoe soles onto shoe shafts. The shoe shafts are drawn over a last that is carried by a movable last slide and are emplaceable upon the sealing edge of molding jaws, which sealing edge bounds a hollow space corresponding to the dimensions of the shoe sole to be formed. The emplacement operation continues until a preselected pressure has been reached between the shoe contour of the shoe shaft nd the sealing edge of the molding jaws. When this preselected pressure is reached, an arresting device is actuated to hold the last slide, and thus the last and shoe shaft, against further movement while the soles are formed on the shoe shafts.

Description

United States Patent Niklaz [54] DEVICE FOR THE SPRAYING OF SHOE SOLES ONTO SHOE SHAFTS [72] Inventor: Manfred Niklarz, Rinteln, Germany [73] Assignee: Stubbe Maschinenfabrik G.m.b.l-l., Vlotho, Germany [22] Filed: Oct. 8, 1970 [21] Appl. No.: 79,006

30 CM, 18/30 CS, 42 l-l,43,17 S. 17 C. 65; 91/24. 27, 28;425/135,l50, 119,125, 214

[56] References Cited UNITED STATES PATENTS 3,522,632 8/1970 Wessel ..18/42 H 51 Sept. 19, 1972 Primary Examiner-J. Spencer Overholser Assistant Examiner-David S. Safran AttorneyMolinare, Allegretti, Newitt & Witcofi [5 7] ABSTRACT The improved device disclosed herein is used for the spraying of shoe soles onto shoe shafts. The shoe shafts are drawn over a last that is carried by a movable last slide and are emplaceable upon the sealing edge of molding jaws, which sealing edge bounds a hollow space corresponding to the dimensions of the shoe sole to be formed. The emplacement operation continues until a preselected pressure has been reached between the shoe contour of the shoe shaft nd the sealing edge of the molding jaws. When this preselected pressure is reached, an arresting device is actuated to hold the last slide, and thus the last and shoe shaft, against further movement while the soles are fonned on the shoe shafts.

6 Claims, 3 Drawing Figures Roudier ..269/22 PATENTED 1 9 m2 3 e92 .449

SHEET 3 {1F 3 Fig.3

IN VEN TOR.

46m /mm DEVICE FOR THE SPRAYING OF SHOE SOLES ONTO SHOE SHAFTS Background Of The Invention The invention relates to an improved device for the spraying of shoe soles onto shoe shafts, and more particularly, to a device wherein the shoe shaft drawn over the last is emplaceable, by means of a movable last slide, upon the sealing edge of the molding jaws, which sealing edge bounds a hollow space corresponding to the dimensions of the shoe sole to be formed.

In automatic soling machines, it is necessary that the shoe shaft drawn over the last is pressed, with an emplacing force, upon the sealing edge of the molding jaws of an injection molding mold, so as to assure that there will not be any expulsion of sprayed material between shoe shaft and the sealing edge of the molding jaws during the spraying operation. Simultaneously, however, it must be assured that the edge pressure between contour of the shoe shaft and sealing edge of the molding jaws does not, in consequence of the emplacing force, lead to the result that the upper portion (the upper leather) of the shoe shaft is damaged or even destroyed.

In the devices already known, the last, with the drawn-on shoe shaft, is moved by means of a pneumatic cylinder, hydraulic cylinder or a toggle lever against the injecting molding mold until the last is held in the desired position by adjustable stops. In these known devices, it is necessary to adjust the stops precisely so that the shoe shaft will be connected, with full sealing effect, with the injection molding mold, without the upper leather of the shoe shaft being damaged or destroyed.

In the case of shoe sole spray materials with poor flow properties, increased injection pressures have to be used so that the sole is exactly developed, and the increased forces resulting from these increased injection pressures attempt to lift or move the last away from the mold so as to lead to the expulsion of material from the mold. If material is expelled, then an expensive, aftertreatment becomes required, which is undersired in any case. In such cases, and particularly when pneumatic or hydraulic actuating cylinders are used, a force is caused to act during the soling process on the actuating (operating) device to which the sole is indirectly fastened. This force is considerably greater than the permissible emplacing force of the last upon the spray mold, i.e., the force at which a damage to the upper leather does not occur. However, because of the use of stops, this force is subdivided, namely, (1) as the emplacing force of the last upon the injection molding mold, and (2) as additional force which is absorbed by the stops. Through the use of stops, a lifting-off of the last from the injection molding mold can be avoided.

These prior devices have the disadvantage, however, that the stops have to be adjusted extremely precisely, whereby valuable working time is lost. Further, in these devices, the varying leather thicknesses in a production course or run are not taken into account, whereby different sealing edge pressures occur on the shoe shaft, and it is not always possible to avoid damage to the shoe shaft. Furthermore, an additional time-consuming arranging of the stops is required if lasts of differing height are used. Here again, the adjustment must be precise since it should be made certain that no material expulsion takes place and, further, any damage to the upper leather should be avoided insofar as possible.

These problems in connection with the spraying-on of shoe soles on shoe shafts are solved according to the invention wherein a variably responding, arresting device is used to fix and hold the last slide in position when a selectable, precisely defined, edge pressure between shaft contour and the sealing edge of the O molding jaws has been reached during the emplace ment operation.

As a result of the use of the arresting device of the present invention, the use of conventional stops is not required and there is nothing to reset or adjust when shoe lasts of differing leather thicknesses are used in a production series or run. Rather, the sealing between shoe shaft and injecting molding mold takes place entirely independently of the most diverse leather thicknesses and the most diverse last heights and there is always an exactly defined emplacing force between the shoe shaft and the mold, which emplacing force prevents any damaging of the shoe shaft and any material expulsion therebetween. In other words, as a consequence of the use of the arresting device of the present invention, the above-mentioned stops, as well as the adjusting process associated with them, are dispensed with, and this provides an appreciable advantage over the prior devices. Here, according to the present invention, upon reaching the defined emplacement force, with which the shoe shaft is pressed against the injection molding mold, the movement of the last, which is connected with the last slide, is arrested so that the force (also called last drive-up force) which builds up in the injection molding mold in consequence of the spray pressure and tends to lift the shoe shaft from the sealing edges of the injecting molding mold is completely absorbed by the arresting device.

The defined emplacing force, which is selected so as to assure that no damage takes place to the upper leather of the shoe last and that no material expulsion occurs, is, for example in the case of a hydraulically operated last slide, preselected and adjusted by means of a variably controllable pressure switch. This defined emplacement force is selected or set only once, and its choice is completely independent of the differing material thickness of the shoe shafts and is likewise independent of the differing heights of the different lasts used. Also, as noted above, the use of the present invention eliminates the complicated and time-consuming arranging and setting required of the stops utilized in the hitherto known devices, as a result of the aforementioned fluctuations in the material thickness of the shoe shaft leather or the shoe shaft material and the use of different last heights.

A preferred embodiment of the arresting device of the present invention is positioned adjacent to the last slide and consists of a spar connected with the last slide and of a locally fixed, deformable shell surrounding this spar. The shell is joinable, in closed linkage, with the spar by action of pressure on a pressure space surrounding the spar.

DESCRIPTION OF THE DRAWINGS In the following, there is described in detail a preferred embodiment of the present invention with the aid of the following drawings wherein:

FIG. 1 shows in schematic representation a device for the spraying of shoe soles onto shoe shafts with an arresting device and an electro-hydraulic control device;

FIG. 2 shows a section from FIGURE 1 in enlarged representation; and

FIG. 3 shows a longitudinal section through the ar resting device, in which the left half of the drawing shows the arresting device in the released state and the right side shows it in the fixed state.

DESCRIPTION OF THE PREFERRED EMBODIMENT The device represented in FIGURE 2 for the spraying of shoe soles onto shoe shafts is used, as a rule, as one station of an automatic soling machine, equipped with several stations. In FIGURE 2, the device, as shown, is set for the rhythmically injecting of plastomers and elastomers into the injection molding mold 1 for an injecting, spray assembly.

Before the start of the injection spraying operation, the last 2 with the lasted-on shoe shaft 3 is emplaced or placed on the injection molding mold 1. Thus, in dependence on the emplacement force between the last 2 and the sealing edge of the mold jaws S, the shoe shaft contour 4 is pressed between the last and the edge of the mold jaws 5.

The emplacing of the shoe shaft upon the mold jaws 5 is accomplished by means of a hydraulically operated cylinder 6 which has a piston 7 slidably positioned therein. The movement of the piston 7 is transferrable through a piston rod 8 extending out of the cylinder 6 directly to a last slide 9 carrying the last 2. The last slide 9 is positioned and arranged such that in the emplacing of the shoe shaft 3 drawn over the last 2 upon the sealing edge of the mold jaws 5, there is accomplished a uniform sealing over the entire circumference of the sealing edge.

In order to increase the production performance of such an automatic soling machine, it is provided, as a rule, that the last 2 is not fastened directly to the last slide 9, but on a turnable last revolver 10, which has two oppositely situated lasts. Through the use of a double last, there is achieved a saving of rirne, because during the soling operation onto the one time, shaft, the finished shoe is de-lasted from the oppositely situated last and thereafter another shoe shaft can be lasted thereto. For reasons of clarity, the second last fastened to the spanning area 11 of the last revolver is not included in FIGURE 3.

The hydraulic raising and lowering of the last 2 is accomplished by the introduction of pressurized fluid on the corresponding piston surfaces of piston 7 through the feed lines 12 in the cylinder 6. The upper limit of the stroke movement of the last is adjustable by means of the support bracket and adjusting screw 13 positioned above the cylinder 6. The limiting of the lowering movement of the last 2 is accomplished by the emplacing of the shoe shaft 3 drawn over the last 2 upon the injection molding form. An arresting device 14, which consists essentially of a spar l5 permanently connected with the last slide 9 and of a locally fixed clamping shell 16 surrounding the spar, arrests or restrains further movement of the last. The construction of this arresting device is more clearly shown in FIGURE 3 and its manner of functioning is to be explained in detail below.

As noted above, in FIGURE 3 the arresting device 14 is shown on the left side of the FIGURE in the released state, while the right side thereof is shown in the arrested state. In the released state of the arresting device 14, the spar 15 is in sliding contact with the clamping shell or sleeve 16. The clamping shell 16 consists of an elastic, thin-walled material, and it is surrounded by a thick-walled cylinder 17, with the shell 16 being sealingl connected with the cylinder adjacent to its ends, so that a closed generally annular pressure space 19 results, which, by means of the opening 20, may be acted upon by a pressure fluidv For the fixing of the last 2 by means of the arresting devices 14, pressurized fluid is admitted to the pressure space 19 and the thin-walled shell 16 moves into contact or places itself-as shown on the right side of FIGURE 3-securely around the spar 15, so that, in consequence of closed linkage between the spar 15 and the shell 16, movement or a lifting off of the last 2 from the sealing edge of the molding jaws 5 is no longer possible. In order to be able to absorb the reaction forces evoked in the arresting device 14, the clamping shell 16 has an internal shoulder 21 on the cylinder 17, and an external shoulder 22 which by means of a shoulder flange 18, is fastened to the machine frame, not shown, of the automating soling machine.

With the aid of the schematic representation shown in FIGURE 1 there will now be described in detail the course of functioning of the arresting device 14. The emplacing of the shoe shaft 3 on the molding jaws, i.e., the lowering of the last slide 9 from its upper rest position, as results when the pressure line 24 is connected with the feed line 25 for causing the lowering movement of the piston 7.

This is accomplished by means of a multiple-way valve 26. The valve 26 is held by springs 27 in a centered or zero position, in which pressure flow is blocked. When one of the two magnets 28 is actuated,

then either the pressure line 24 is connected with the feed line 25 for the descending movement of the piston 7 or the pressure line 24 is connected with the feed line 29 for the lifting movement of the piston 7, while simultaneously the remaining feed line or the other line from the cylinder 6, i.e., the line then functioning as lead-off from the cylinder 6, is connected with the tank or sump 30.

The speed of the lowering and lifting movement of the piston 7 can be influenced by adjustable valves 3] and 32 in the

lines

25 and 29, respectively. These

valves

31 and 32 are constructed as choke, nonreturn valves, whose constriction is effective, in each case, only in connection with flow in the direction of the runoff or lead-off from the cylinder 6.

When the pressure line 24 is connected with the feed line 25, then the last 2 descends. After the emplacing of the shoe shaft 3 upon the sealing edge of the molding jaw 5, the pressure of the fluid in cylinder 6 above the piston 7 builds up to a preselected, final value, which causes the requisite edge pressure between shoe shaft and injection molding mold. The emplacing force resulting from this preselected final pressure is sensed by a conventional pressure switch 33 which is connected with the upper end of the cylinder 6, and which on the reaching of this pressure, places a controlling voltage on the conventional relay R. The relay R operates a working contact r whereby, by means of a magnetically operated multiple-way valve 34, the pressure line 24 is connected, by means of the feed line 35, to the pressure space 19 of the arresting device 14. Thereby the last 2 is arrested or held in the position wherein the previously exactly defined edge pressure exists between shoe shaft and the sealing edge of the molding jaws so as to make possible an expulsion-free spraying, (injection) and also to prevent any damage to the shoe upper leather.

To prevent the pressure above the piston 7 from rising inadmissibly high after. the arresting device has been activated, and for reasons of safety, a conventional adjustable pressure reducing valve 36 is installed in the feed line 25 to the cylinder 6.

After completion of the injection process and after the passing of a required vulcanization or hardening time, the finished footwear is lifted by means of the last 2 from the injection molding mold 1. More specifically, through the operation of the multiple-way valve 26, the cylinder space above the piston 7 becomes pressureless, i.e., connected to the tank or sump 30, and simultaneously the feed line 29 is connected with the line 24. Immediately after the lowering of the pressure in the cylinder space above the piston 7, the control voltage is taken from the relay R by means of the pressure switch 33, whereby the working contact r falls or opens and the multiple-way valve 34 is brought, by means of the spring 37, into its zero position, in which it connects the line 35 with the tank or sump 30. Thereby, the arresting device 14 is, thus, released, so that the lifting movement of the last 2 can be initiated.

The foregoing is a description of the preferred embodiment of the present invention, and the scope of the invention includes all modifications, which would be obvious to those skilled in this art, to the invention as described in the following claims.

I claim:

1. An improved device for the injection of the shoe soles onto shoe shafts adjacent to the contour of the shoe shaft comprising:

last means over which shoe shafts may be drawn;

mold means including molding jaws having a sealing edge which defines a hollow space corresponding to the dimensions of the shoe sole to be formed on the shoe shaft;

last slide means connected to the last means and movable to emplace the shoe shaft drawn over the last means upon the sealing edge of the molding jaws of the molding means; and

arresting means for selectively holding the last slide means against further movement; means for sensing the pressure exerted by the shaft contour ofthe shoe shaft on the sealing edge of thc molding jaws of the molding means during emplacement of the shoe shaft drawn over the last means upon the sealing edge of the molding jaws of the molding means, the pressure sensing means including means for actuating the last slide arresting means so that the last slide arresting means holds the last slide means against further movement, when a preselected pressure has been reached between the shaft contour of the shoe shaft and the sealing edge of the molding jaws of the moldingmeans. 2. T e improved device as described in claim 1 wherein the arresting means includes: a spar connected to and movable with the last slide means and a means for selectively gripping the spar so as to prevent further movement thereof.

3. The improved device as described in claim 2 wherein the gripping means includes: a cylinder means surrounding the spar and an elastic means disposed between the cylinder means and the spar which may selectively engage the spar.

4. The improved device as described in claim 3 wherein the elastic means is an annular elastic member which is connected at its ends with the cylinder means so as to define space between the elastic member and the cylinder means; and wherein the cylinder means includes means for introducing pressurized fluid into the space between the cylinder means and the elastic member for causing the elastic member to be expanded against the spar.

5. The improved device as described in claim 4 wherein the last slide means is moved in a shoe shaft emplacing direction by a hydraulic fluid piston and cylinder means; wherein the pressure sensing means senses the pressure of the hydraulic fluid acting in the hydraulic fluid piston and cylinder means; wherein the means for introducing pressurized fluid into the space between the cylinder means and the elastic member is actuated by the actuating means when the pressure of the fluid acting in the hydraulic piston and cylinder means exceeds a preselected value.

6. The improved device as described in claim 5 wherein when the pressure of the hydraulic fluid acting in the hydraulic piston and cylinder means falls below said value, the pressurized fluid in the space between the elastic member and the cylinder means is placed in communication with a sump whereby the spar is again free to move with respect to the cylinder means.

Claims

1. An improved device for the injection of the shoe soles onto shoe shafts adjacent to the contour of the shoe shaft comprising: last means over which shoe shafts may be drawn; mold means including molding jaws having a sealing edge which defines a hollow space corresponding to the dimensions of the shoe sole to be formed on the shoe shaft; last slide means connected to the last means and movable to emplace the shoe shaft drawn over the last means upon the sealing edge of the molding jaws of the molding means; and arresting means for selectively holding the last slide means against further movement; means for sensing the pressure exerted by the shaft contour of the shoe shaft on the sealing edge of the molding jaws of the molding means during emplacement of the shoe shaft drawn over the last means upon the sealing edge of the molding jaws of the molding means, the pressure sensing means including means for actuating the last slide arresting means so that the last slide arresting means holds the last slide means against further movement, when a preselected pressure has been reached between the shaft contour of the shoe shaft and the sealing edge of the molding jaws of the molding means.

2. The improved device as described in claim 1 wherein the arresting means includes: a spar connected to and movable with the last slide means and a means for selectively gripping the spar so as to prevent further movement thereof.