US2917840A - Heel and base assembly - Google Patents

Description

Unimd tes Patent Stow, Mass, assignors to Beckwith-Arden Inc., Watertown, Mass., a corporation of New Hampshire Application October 23, 1958, Serial No. 769,150

' 4 Claims. (Cl. 36-35) :.This invention comprises a new and improved heel assemblyzincluding as its components .a base of resinous compositionand a rubber heel section. These components, in accordance with our invention, are provided with interlocking recesses and projections which register theinbrea'st walls in flush relation and so obviate or greatly reduce the trimming operation that has been heretofore necessary .after treatment to the shoe bottom.

5- .Ithas been customary for the operator of the heel nailing machine to assemble the components of the heel 'byhandain presenting them to the machine and subsequently. their peripheral walls are brought into registration by a trimming operation removing an average of at leastl gram perbase. Dealing with bases of polyethylenethis 'means a waste of at least $1.10.v per thousand bases.a :nI- l .r .We. have found that there is inevitably a variable amount of-expansion in different rubber heel sections in the attachinggoperation and consequently .it is impossible 'to insure flush" registration of the entire peripheral surfaces'of the two components. However, we have discovered that by novel interlocking provision, it is possible to. establish and retain accurate and precise registration of'theheel breast surfaces of the base and rubber heel sectionsl An important advantage of this-is that thus the hee'li breasting.operation is obviated and what trimming remains to be donecinvolves only the curved periphery of the rubber section .or of both'sections, a step that is entirely'compatible with the routine rand trimming step.

Byleliininating theheelbreasting and scouring operaftidns',;.we also avoid the danger of incidental damage to the outsole which has often occurred in the past, and facilitate the employment of prefi nished 'outsoles.v

We securethe desired results by interlocking the two components together in a locationclosely adjacent to their breast surfaces, thus positively locking them in flush relatioii landwith a minimumofrubber' disposed between tli -loc'k ing'means andthe breastzsurface. i 'iT'Our-invntion has other outstanding advantages, however. It points the way to further-reductions in weight of both the base and rubber. heel sections by providing inp ternal cavities into which areas of mutual support project, and the registration of the areasis made possible by the accurate interlocking engagement of the two components of the heel effected at the time of their preliminary engagement.

In molding the base it is advantageous to utilize a central gate for injection into the mold of the viscous polyethylene or other synthetic resin, and accordingly the sprue formed below this gate is utilized as a' central supporting abutment and the heel is provided with a mating abutment in its otherwise hollow interior.

Further, the accuracy introduced into the assembly permits the nail-receiving abutments of the base section to be reduced in their dimensions thus reducing the weight of plastic in the assemblybut at the same time insuring sufiicient stock to hold the heel securely. The assembly thus includes two'components both having large internal 7 2,917,840 Patented Dec. 22, 1959 2 cavities but with cooperating and registering abutments and lugs that support each other and give stability to the unbroken tread surface of the rubber heel section.

The saving in material above outlined may amount to as much as 10 or 15% of the cost established in the industry. Additional advantages accrue in the following respects. The amount ofwaste removedin trimmingis entirely eliminated at the breast-of the heel and an exceptionally-true gauging surface is provided for trimming the rand, which is probably all that the trimmer will have to deal with. Labor cost may thus be reduced and the breast-trimming 1 operation eliminated. The total weight of the heel assembly-is reduced and the quality of the shoe thus improved.

Theseand other features and advantages of the invention will be best understood and appreciated from the following description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings in which:

Fig. 1 is a plan view of the base and heel assembly,

Fig. 2 is a view in longitudinal section on the line 22 of Fig. 1,

Fig. 3 is a view in cross-section on the line 3 -3- of Fig, 1,

Fig. 4 is a plan view of the rubber heel section,

Fig. S-is an inverted plan view of the base, and

Fig. 6 is a fragmentary view in section.

' The base 10-as herein shown is molded of polyethylene or other suitable synthetic resin and as such is tough, moisture-proof and of lightweight. Furthermore, in molding its peripheral wall takes a high degree of finish and may be'polished without any intermediate trimming steps. The peripheral wall of the base defines and surrounds an internal recess or cavity 11- which extends entirely through the base, its wall'there fore being of annular character. A series of spaced abutments 12 project inwardly into the recess 11 in position to receive the attaching .nails and to underlie corresponding lugs which areformed in the rubber heel section. V The base also contains a centrallydisposed arrowshaped'post 13 which is in effect part of the sprue formed below the gate in the upper mold used in molding the base. The post 13isconnected through a neck toan abutment which projects inwardly from the breast wall 'ofthe base. In molding the base the plastic resin forced into the mold in the location of the post 13. It flows "forwardly into the breast wall portion of the base and spreads Qrearwardly uniting "at the rear end of the heel." :It" has been found that. this :molding procedure ,insures a highly satisfactory surface finish particularly throughout'the rear curved wall of the base. I K Theiu'ppe'i" surface of the base as shown'in Figs. 2'and 3.is concave while the lower 'face is flat except that in Fig. 4 is molded with its peripheral wall corresponding to that of the base so that when the two components are assembled in substantial registration there is little necessity for trimming. The peripheral walls of the heel surround an interior cavity 21 corresponding in general to the cavity 11 of the base but closed by the tread portion of the heel. Into the recesses 21 project a series of spaced lugs 22 arranged to register and be supported by the abutments 12 of the base and each properly located to receive an attaching nail and for that purpose being provided with a washer as indicated in dotted lines. The rubber heel also has a central post 23 rising from the solid tread portion in alignment with the post 13 of the base. Both faces ofrthe rubber heel section are substantiaily fiat and in its upper face as shown in Figs. 2 and 4 is formed a pair of transverse slots or grooves 24 extending parallel to the breast edge and shaped to receive theribs 14 of' the base witha: close fit which willqinsure accurate registration of the breast, faces of thetwo components; in flush relation.

In the upper face of the section near its rear end is formed a longitudinal slot corresponding in'width to the diameter of the pin 15 of the base section and being of suflicientlength to afford lost motion of the pin longitudinally of theheel assemblyand thus to allow for. variations in the. expansion of this section ingrelation IO'ltS breast which is positively fixed inqposition by the interlocking of theribs 14 with the grooves '24.

v'Ihexprecise shape and location of the interlocking projections. and cavitieson the contiguous faces of the two components is of secondary importance so long as they are adequate to insure the desired breast registration of thecomponents. The same is true of the abutments and post of the base and the nail-receiving lugs of the rubber heel section. Their contour may be designed with consideration for the function they perform in the assembly and their pleasing appearance as articles of commerce. 'The internal walls of the cavities ,11 and 21 may be beveled or sloped if desired to a greater degree than suggested in Figs. 2 and 3.

While the most important advantages of the present invention arerealized in composite heel assemblies that include a cushion heel section of rubber or other resilient material, the saving in weight and the eliminationof the heelxbreasting operation are advantages that are found in dealing with heel sections of non-resilient materials.

It has been found that the expansion of a cushion section due to pressure of the attaching nails tends to modify the contour of the section and it is thereforeimportant to compensate for this expansion in the design of'the-section and reduce it to a minimum. For example, if longitudinal expansion of a rubber heel sectionis in the order of .010 inch per inch the expansion of the rubber between the grooves 24 and the breast edge of thesection will be only .0012 inch if the grooves. for the ribs 14 are located /8 inch in from the breast edge. Similarly, the heel attaching. nails may displace laterally the material at the corners of the heel breastandtherefore :the initial breast curvature is made slightly more pronounced than that of the corresponding resinous base.

The superposition of the rubber lugs 22 upon resinous abutments 12 improves the cushion effect of the rubber section by giving the lugs freespaceinto which they. may

expand when subjected to pressure. This permits the employment-of a harder andlonger-wearing rubber composition than would otherwise ,be required for equal cushion efiect.

The advantages of the present invention may be summarized as follows: (1) saving in rubber, (,2) saving in resinous plastic, (3) elimination of heel breasting and scouring operations, (4) obviates the danger of damage .to the outsole shank, and (5) improves the cushion effect of theassembly.

Having thus disclosed our invention and described in detail an illustrative embodiment thereof, we claim as new and desire to secure by Letters Patent:

1. A heel assembly comprising a base of resinous composition having a breast'wall and curved walls surrounding an internal cavity, a series of spaced abutments formed integrally with said walls projecting into said cavity, and a rubber heel section having a breast wall and curved walls, a series of nail-receiving lugs formed int tegrally with said walls and spaced to register with said abutments of said base, and interlocking connections between said base and rubber heel section registering their breast faces in flush relation.

2. A heel assembly comprising, in combination, a base of relatively light-weight, tough, resinous composition, and a rubber heel section, said base having a finished peripheral wall, a breast edge and a hollow interior, a series of supporting abutments formed integrally with said peripheral wall and projecting. inwardlyinto.. -said hollow interior, saidbasehaving a.lower. flat face,.=a; rib projecting downwardly from said lower. fiatiace and posie tioned substantially parallel to itsbreast edge;.said rubber heelsection also having a finished-peripheralv .wall, .-a breast edge and ahollow interior, a seriesof nail-receiving lugs formed integrally with said peripheral .walland pro,- jecting into said hollow interior, said lugs. underlying said abutments and flat face of said base, said.heel.section having a groove positioned adjacent said breastuedge shaped toreceive said rib of said base and toregister said base and. rubber heel section with their breast faces in flush relation.

.3. Ina heel assembly, a base of resinouscomposition having a curved breast edge. wall merging into a U-shaped peripheral wall defining an internal cavity in the base a rib-projecting downwardly. from said breast edge wall, a central abutment connected to. said breast edge wall at a point behind the rib, and a pin projecting downwardly from the peripheral wall near the rear of. the base, said rib and pin being adapted to interlock with grooves formed in a heel section.

4. In a heel assembly, a rubber heel section havingea peripheral wall rising from a flat tread portion and defining an internal cavity, and a central postrisingifrom the tread portion and of substantially the same height as the peripheral wall, theperipheral wall havingxan elongated transverse slot in its breast portionand. an elongated longitudinalslot'in its rear portion, saidtransverse slot. and. said longitudinal slot being adapted. to interlock, respectively, with a rib and. pin projecting downwardly froma base.

References Cited in the file of this patent UNITED STATES PATENTS t Litchfield J an. ;15, .1901

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