US2914782A - Shoe pad boxes - Google Patents

Description

Dec. 1, 1959 Filed May 8, 1958 F. A. PRAHL, JR., EI'AL snos PAD BOXES 4 Sheets-Sheefl Fred ,4 Pmhl, JP; and Era/d 0- Def nse" .9%,?! 7

attorney Dec. 1, 1959 F. A. PRAHL, JR, ETAL 2,91

SHOE PAD BOXES 4 Sheets-Sheet 2 Filed May 8, 1958 V I] as $15 MM WM 1% Dec. 1, 1959 Filed May 8. 1958 F. A. PRAHL, JR., ETI'AL Iaweniom; Fred 4. Rnzhl, -77- mi Era/d 0- R v United States Patent srron PAD BOXES Fred Prahl, .lr., Harvard, and Evald 0. Peterson, Lynn- 'field, Mass., assignors to Compo Shoe Machinery Corporation, Waltham, Mass., a corporation of Delaware Application May 8, 1958, Serial No. 733,906

1 Claim. (Cl. 12-38) This invention relates to pad boxes used inwthe cementing of shoe soles to shoe uppers.

For use in the cementing of shoe soles to shoe uppers, a widely used form of pad box has a thin, easily stretchable, soft rubber diaphragm clampe d, with a leather panel, to the pad box, the leather panel being used to apply pressure to the shoe sole. A problem encountered with this type of pad box has been that the operating characteristics of the pad box change as the leather panel stretches out. The continued stretching of the leather panel has caused reductions in the quality of sole attaching, and the continued stretching .of the diaphragm and leather panel has caused premature failures of both. Also, with the soft rubber diaphragm previously used, the unit pressure created on the bottom of a shoe sole has been uniform over the whole bottom surfacev of a shoe sole. v

feature of this invention is that it provides'a reinforced, relatively poorly sretchable, rubber diaphragm which not only eliminates excessive stretching of the diaphragm and its associated leather panel, but enables when the diaphragm is dilated, greatly concentrated pressures to be applied to the outer portions of a shoe sole.

Another feature of this invention is that a rubber bridge is provided between the bottom of the pad box and the diaphragm in its shank area, and a pair of rubber wedges is provided between the diaphragm and the leather panel in the shank area. These cause, when the reinforced diaphragm is dilated, concentrated pressure to be applied to the outer portions of the shank area of a sole, practically eliminating any pressure on the center portion of the shank area of the sole between its edges.

An object of this invention is to improve the quality of shoes having soles cemented to uppers.

Another object of this invention is to increase the lives of rubber diaphragms and leather panels used in pad boxes.

Another object of this invention is to limit the stretching of rubber diaphragms and leather panels used in pad boxes.

Another object of this invention is to increase the pressures applied by the leather panel of a pad box to the outer portions of an outsole;

This invention will now be described with reference to the annexed drawings, of which:

i Fig. 1 is a plan view looking downwardly upon a pad box embodying this invention;

Fig. 2 is a section along the line 2-2 of Fig. 1, with the diaphragm of the pad box not dilated;

Fig. 3 is a plan view of the bottom of the leather. panel of the pad box;

Fig. -4 is a plan view of the top of the rubber diaphragm of the pad box;

Fig. 5 is a section along the line 55 of Fig. 4;

Fig. 6 is a section along the line 6-6 of Fig. 2 with the diaphragm not dilated;

, Fig. 7 is a section along the line 7--7 of Fig. 9, with the diaphragm dilated;

"See

Fig. 8 is a section along the line 88 of Fig. 9, with the diaphragm dilated;

Fig. 9 is a section corresponding to Fig. 2 but with th diaphragm dilated, and

Fig. 10 is an enlarged, fragmentary section through the rubber diaphragm.

A pad box casing 10 of conventional construction, has clamped thereto by a metal ring 11 and bolts 12, the edge portions of a rubber diaphragm 14 and a leather panel 15. A tube 16 for connection to a conventional source of compressed air which is not shown, connects through a fitting 17 with the space 18 between the bottom of the diaphragm and the casing. A shoe on a last 24, and having an upper 19 and a sole 20, is shown in operating position on the leather panel '15, being held in such position by a conventional toe clamp 21 and a conventional heel clamp 22. The shoe upper has insole lasting margins 23 which are spaced apart under the last, the usual metal shank piece 29 being placed between the lasting margins.

The bottom of the leather panel 15 has a layer 25 of leather reinforcement cemented to its fore portion, and has a layer 26 of leather reinforcement cemented to its heel portion. A steel plate 27 is held between the heel layer 26 and the bottom of the panel 15.

The diaphragm 14 is reinforced by having two rows of tire cords 28 imbedded therein, the cords in one row extending, as shown in the cut-away portion of Fig. 4, at angles of 90 to the cords in the other'row. The cords extend along a bias angle of 45 to the longitudinal axis of the diaphragm.

i A rubber bridge 30 extends transversely across and is cemented to the bottom of the diaphragm in its shank area. The top of the diaphragm has cemented thereto above the bridge 30, a pair of transversely spaced-apart, rubber wedges 31 which extend forwardly and rearwardly above the bridge 30.

push the panel 15 into the sharp curve of the shoe as shown by Figs. 2 and 6. Then, when the diaphragm is dilated, no air pressure is lost in attempting to stretch the leather panel into the contour of the shoe bottom. When the diaphragm is dilated by air pressure, the pressure exerted by the leather panel against the surface of the shoe bottom is increased to the proper operating pressure.. It will be understood that, as is usual in the cementing of shoe soles to shoe uppers, the shoe sole and bottom will have had their adjacent surfaces coated with adhesive before being placed in the press, and that'the pad box supplies the proper pressure to hold the insole and outsole together until the adhesive has set.

The reinforced diaphragm and the rubber wedges, as shown by Figs. 7-9, make possible the application of full pressure at the rounded edges of the lasting margins 23, with no pressure at the transverse centerportion of the shank where the lasting margins are spaced apart, and

between which is the metal shank piece 29. A transversely rounded shank portion is produced without the necessity of the expensive filling-in steps used in the past to provide the rounded shank portions.

In the shank portion of the shoe where the sole is narrow, and the last contours are round, this concentration of force at the edges cannot be accomplished by using a soft, easily stretchable diaphragm and leather panel of the prior art.

In our invention, the top surfaces of the wedges 31 bear against the cemented, marginal edge portion of the shank area of the outsole so that the reinforced diaphragm will transfer the accumulated unit pressure on its under surface through the wedges to their upper surfaces, and through the latter to the cemented areas of the shank of the outsole, so that a much higher pressure is developed on the cemented areas of the shank of the outsole than would be possible by a direct pressure from the previously used, relatively flexible rubber diaphragm. Not only is the pressure concentrated in this manner, but dilation of the diaphragm will cause the wedges to roll up, creating the rounded surfaces desired by shoemakers, on the shank portion of the shoe. A poorly stretchable diaphragm is required for producing this re sult since the lack of substantial stretchability prevents it from ballooning up alongside of and between the wedges further than shown by Fig. 8, and causes instead, substantially its full pressure to be applied against the wedges to produce the desired rounded shank.

In the forepart portion of the shoe, the lack of substantial stretchability of the diaphragm, causes as is shown by Fig. 7, concentrated pressure to be applied to cemented marginal portions of the forepart of the outsole.

The leather panel reinforcement provided by the added layer 25 of leather in the forepart of the panel, limits the conformation of the panel to irregularities which may be present in the forepart of the shoe bottom. The leather panel reinforcement provided by the added layer 26 of leather, and by the metal member 27 prevents the breaking down of the lasted heel.

While a rubber diaphragm is referred to in the description and claim, the word rubber is intended to mean synthetic as well as natural rubber and its equivalents.

What we claim is:

A shoe pad box comprising a casing having a bottom, a rubber diaphragm having a substantially ovalshaped outline with its bottom spaced from said casing bottom, a leather panel having an outline similar to said outline of said diaphragm overlying said diaphragm and having its edge in contact with the edge of said diaphragm, means for clamping said edges of said diaphragm and panel to said casing, said panel having a shoe shank contacting portion, a pair of transversely spaced-apart, longitudinally extending, rubber wedges on the top of said diaphragm under said shank contacting panel portion, a transversely extending, rubber bridge in contact with the bottom of said diaphragm under said wedges, and means'for supplying air under pressure into the space between said diaphragm and casing bottom.

References Cited in the file of this patent UNITED STATES PATENTS 1,725,103 Ray Aug. 20, 1929 1,790,192 Winkley Jan. 27, 1931 2,095,658 Card Oct. 12, 1937 2,099,393 Gordon Nov. 16, 1937 2,205,400 Finn June 25, 1940 2,311,325 Anderson 2 Feb. 16, 1943 2,348,060 Dawson May 2, 1944 2,428,814 Russo Oct. 14, 1947 2,733,462 Pratt Feb. 7, 1956 2,772,428 Suerken Dec. 4, 1956

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