US2228937A - Boot-and shoe-tacking machine - Google Patents

Description

Jam. 14, 194.. K WQLLNY BOOT AND SHOE-"PACKING MCHINE Filed May l5, 1939 2 Sheets-Sheet l Jan.. 14, 1941. K, WOLLNY 2,228,937

BOOT- AND SHOE-TACKING MACHNE Filed May 113, 1939 2 Sheets-Sheet 2 Patented Jan. 14, 1941 PATENT OFFICE BOOT- AND SHOE-'PACKING MACHINE Karl Wollny, Weissenfels-Saale, Germany, as-

signor to the rm Nollesche Werke, Komm. Ges., Weissenfels, Germany Application May 13, 1939, Serial No. 273,510 In Germany June 21, 1938 2 Claims.

The invention relates to nailing, tacking or pegging machines for boot and shoe manufacture.

`Tacking and like machines are known wherein the gripper is closed by a closure lever controlled by a cam disc, and during the overlaying or wiping of the marginal portion of the upper is held in the closed position with reduced pressure by a step of the control cam.

According to the invention a machine of this kind is provided with two springs of dierent strength between the closure lever and the gripper closing device so arranged that during the upper pulling operation by means of the gripper both springs are operative and during the overlaying or wiping of the margin of the upper by the wiper only the weaker spring is operative.

The two springs may exert a closing pressure of variable strength which is adjustable individually for each spring. By this means during nailing or tacking on, especially of the toe of the shoe, a very powerful closing pressure can be obtained by the gripper and a correspondingly high tension applied to the leather for the pulling on, whereas the holding pressure, which the gripper has to exert during the overlaying operation of the leather edge, is low, and adjustable and quite independent of the gripper-closing pressure maintained during the pulling or stretching of the leather.

In stretching or pulling the upper the spring which can exert the stronger closing pressure is operative, and for the overlaying of the margin of the upper the other spring With the lower gripper-closing pressure comes into operation.

As separate adjusting devices are provided for each spring, the spring for supplying the lower holding pressure on the gripper can be completely stressed during the stretching operation of the leather so that only the strong spring is in operation whereas during the overlaying of the margin of the upper the closing pressure of the main spring on the gripper is completely released.

It is possible without further provision to equip existing machines with this supplementary arrangement, since for this purpose only the exchange of the gripper-closing lever and the control cam of the cam disc is required, rIhis can be carried out in the simplest and quickest manner without disturbing the remainder of the machine structure. Advantageously the second spring, namely the plunger of this additional spring, is mounted in the main spring plunger carried by the gripper-closing lever, the hollow of the spring 5 of the main plunger 3.

shaft of which main plunger provides the abutment for the spring of the additional plunger.

The invention is illustrated in the accompanying drawings in my constructional arrangement by way of example. 5

Figure 1 shows a front view of a tacking-on machine with a known arrangement of gripperclosing lever, partly in section.

Figure 2 shows a corresponding front view of the machine with 'the gripper-closing lever and 10 control cam according to the invention.

Figure 3 shows a side View of the gripper-closing lever shown in Figure 2.

Figure 4 shows a view of the gripper.

Figures 5 to 7 show different working posi- 15 tions of the gripper-closing lever.

Figures 5a to 'la show the positions of the gripper corresponding with the lever positions shown in Figures 5 to 7.

In the known construction according to Fig- 20 ure 1 the gripper device I is brought into the closed position by the closing lever 2, whose plunger 3 bears upon the press rod 4 of the movable gripper jaw. The plunger 3 is under the influence of a spring 5 whose pressure can be reg- 25 ulated by a screw sleeve 6. The closing lever 2 is securely keyed on the shaft 'I on which the lever 8 is similarly rigidly connected. The roller 3 of the lever 8 lies against the closure cam Ill of the cam disc I I.

Upon the rotation of the cam I0, the spring plunger 3 is forced down on the press rod 4 by means of the roller 9 and the levers 8 and 2, so that the .gripper is closed and the margin of the upper is gripped. The gripper remains closed so long as the roller 9 runs on the closure cam I9 and the jaws will be forced together with equal force during the whole of this time.

In the example of construction of the invention illustrated in Figure 2, an auxiliary plunger I2 is 40 mounted in the spring plunger 3 and is under the influence of a spring I3.

The pressure of this spring, which can be regulated by the set screw I4 is weaker than that AS a result, on the forcing down of the gripper press rod the auxiliary plunger I2 rst of all yields, stressing its spring I3, and then causes a rising movement of the main plunger 3 with stressing of its spring 5.

The control cam surface I5 for the roller 9 on the cam disc II has a dwell step I5 which is so determined as to hold the jaws still under the pressure of the auxiliary plunger I2 and its spring I3 during the overlaying of the leather of 55 the upper. The keying of the control cam I5 on the cam disc II is effected through slots I6 and screws II so that the cam can easily be changed and adjusted. The roller 9 of the lever 8 can be maintained against the control cam I5 in known manner by means of the torsion spring I8.

In Figures 5 and 5a the commencement of the closing movement of the gripper is shown. As the roller 9 runs on to the closure cam I0 the gripper-closing lever 2 is swung on to the press rod 4. In this position the vgripper is still held open by its own spring I9. When on the other hand, the roller 9 has run on to the cam I5 (Figure 6), then rst the auxiliary plunger I2, and in turn the main plunger 3, is pressed upwardly in the lever 2 so that by this time the pressure of the stronger spring 5 comes into operation on the press rod 4, and the movable jaw 20 and fixed jaw 2l of the gripper close securely on to the margin of the upper, (Figure 6a). After the stretching of the margin of the upper and during the movement of the wiper 22, the roller 9 reaches the dwell step I5' in the -control cam. This swings the gripper-closing lever 2 by means of the spring I8 and the springs of the plungers 3 and I2 back to some extent, s0 that, as shown in Figure '7, the main plunger 3 moves back to its rest position and now only the auxiliary plunger I2 with its spring I3 is operative von the rod 4. The gripper is thus held closed only by a pressure corresponding to that of the spring I3 and therefore the wiper can gradually draw the edge of the upper out of the gripper. The running off of the roller 9 from the control cam step I5 returns the closure lever 2 with its plungers to the rest position Figure 5.

What I claim is:

1. Boot and shoe-nailing and like machines wherein the gripper for pulling the upper is closed by a lever controlled by a lever controlled by a cam and during the overlaying of the margin of the upper is held closed but with reduced gripping power by a step of the control cam including an auxiliary plunger acting on the gripper-c1osing device, a hollow main plunger in which the auxiliary plunger is mounted and which acts to depress the auxiliary plunger, a spring in the main plunger acting on the auxiliary plunger, and a relatively stronger spring acting on the main plunger whereby during the stretching or pulling of the upper leather by the gripper both springs are operative while, on the other hand, during the overlaying of the margin of the upper only the weaker spring is operative.

V2. A construction as defined in claim 1 wherein a set screw is mounted in the shaft of the main plunger for adjustment of the spring therein.

KARL WOLLNY.

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