US3189993A

US3189993A - Method of preparing a metal dowel to receive molded resilient material

Info

Publication number: US3189993A
Application number: US372656A
Authority: US
Inventors: John B Whitted; Jr John B Whitted
Original assignee: WHITSO Inc
Current assignee: WHITSO Inc
Priority date: 1964-06-04
Filing date: 1964-06-04
Publication date: 1965-06-22
Anticipated expiration: 1982-06-22

Description

June 22, 1965 J. a. WHITTED AL 3,189,993

METHOD OF PREPARING A METAL EL TO RECEIVE MOLDED RESILIENT MATERIAL Original Filed Sept. 22, 1960 2 Sheets-Sheet 1 F151 FE z June 22, 1965 J. B. WHlTTED ETAL METHOD OF PREPARING A METAL DOWEL 'I'O REGEIV 2 Sheets-Sheet 2 MOLD Original Filed Sept. 22, 1960 United States Patent METHOD OF PREPARING A METAL DOWEL TO The present invention has to do with a method of preparing a metal dowel to receive molded resilient material and more particularly relates to the method as applied to a steel dowel used to support a resilient rubber-like material comprising the heel lift of a ladies high heel shoe.

This application is a continuation of our co-pending application S.N. 57,733, filed September 22, 1960, now abandoned and entitled Method of Preparing a Metal Dowel to Receive Molded Resilient Materia In recent years ladies shoe styles have tended to smaller and smaller heel sections so that the high heels of fashionable shoes have presently a lift of about inch square. The lift, of course, is of the usual configuration generally having fiat or slightly concave surfaces at the front and a rounded rearward part matching the contour of the heel and comprising an extension of the outer decorative surface of the heel. Great difficulty has been experienced in securing an adequate bond between lift material and a metal dowel which is driven into the heel lengthwise to reinforce the heel as well as to support the wear surface provided by the lift material. Various bonds have been attempted including adhesive materials and mechanical bonds. Neither has proven satisfactory during walking, as a lady places considerable stress upon the very small section of the heel lift. The tendency to tear the heel lift loose is quite great. Normally headed dowels are generally ineffective for the reason that the resilient material inherently has the ability to part sufficiently to pass over the head. A nail-head shape thus may pull out of resilient material because the material gives easily to slip past the head. The construction of the dowel in accordance with the present invention obviates the difficulties previously made.

The principal object of this invention is to provide a new and improved method of making a dowel for a heel lift as described.

Another object is to provide an improved method of making a dowel of the character described which permits the dowel to sufficiently compete in production cost with previous constructions.

Another object is to provide a method of making a dowel suitable to automated procedures.

A further object is to provide novel methods of making a dowel which may result in a structure more effective to retain resilient material molded to the dowel.

Other objects, features and advantages of the present invention will be apparent from the following description of a preferred method involving the invention and as illustrated in the accompanying drawings in which:

FIGURE 1 is a diagrammatic sectional view through the parts of an appropriate die illustrating the first step in the invention.

FIGURE 2 is similar to FIGURE 1 showing the die and hammer in closed position.

FIGURE 3 is a plan view of the piece part following its head in the die of FIGURES 1 and 2.

FIGURE 4 is an illustration of the piece part in plan showing a further step in its manufacture.

FIGURE 5 is a plan view illustration showing a drilling step of the invention.

FIGURE 6 is a plan view of the piece part showing in dotted outline the location of the molded resilient material in the finished heel lift.

FIGURE 7 is an enlarged horizontal sectional view through the dowel looking toward the head showing the dowel in its condition when removed from the die.

FIGURE 8 is a fragmentary illustrational view of the head of the dowel following the method step illustrated in FIGURE 5.

FIGURE 9 is a bottom plan view of the dowel as it appears in FIGURE 8.

FIGURE 10 is a sectional view through the dowel taken substantially along line 10-10 in FIGURE 9.

FIGURE 11 is a horizontal sectional view through the dowel looking toward the head taken substantially along line ill-11 in FIGURE 8, and

FIGURE 12 is a view of the dowel substantially like I :7

FIGURE 7 looking toward the head.

The material of which the dowel is formed is a straight round steel wire stock from which a length is 'cut to form a blank 15 suitable for insertion into a heading die 16 so that the blank rests upon a knock-out pin 17. The hammer i s associated with the die is provided with a round centering punch 19 adapted to penetrate the flat upper end 20 of the blank 15 providing a center for a later drilling operation. The die has a cavity21 into which the steel material of the upper end of the blank 15 is caused to flow forming an enlarged head of particular configuration. In FIGURE 2 a head 22 is shown as formed upon the blank 15 and the hammer 18 has been caused to close upon the die 16. In some instances the steel blank may be raised in temperature above ambient in order to aid the flowability of the upper end of the blank into the cavity 21.

Once the dowel has been headed it is removed from the die and rolled at the opposite end 23 to provide a slight taper. In the same or separate rolling step, a longitudinal extending knurl 24 may be added to the stem of the dowel to give the dowel a means of gripping the heel material into which it may be driven.

The particular form and shape of the head on the dowel resulting from the heading operation is particularly important. Referring to FIGURES 7 and 12, it may be observed that the head has an outer circular flange 25 joined to the stem 26 by three post-like bosses 27 extending longitudinally of the dowel. At the juncture of the dowel stem 26 and head 22 a smaller flange 28 is present and used in a later molding step to shut off communication through the mold with the cavity for the stem 26. The surfaces or sides 29 extending between the post bosses 27 are generally arcuate and are seen in FIGURE 7 as a line since the surfaces extend longitudinally of the dowel. The posts 27 are arranged at the corners of an equilateral triangle and the surfaces 29 generally approximate the sides of the triangle although they are slightly arcuate. The distance between the center of the dowel and the surfaces 29 is accurately controlled by the configuration of the cavity 21 in the die so that each such surfaces has equal distance from the center of the dowel. Referring particularly to FIGURE 12, the drill centering cavity 39 is also centered on the center line of the dowel.

Following the steps in the method previously described the dowel is automatically chucked in a screw machinetype of operation in order that the head may be hollowed out by a drilling operation. Referring to FIGURE 5, a drill 311 is caused to enter the head 22 so that the axis of the drill and the center line of the dowel are co-linear. The drill is caused to penetrate the head a sufficient distance to remove the metal comprising the sides 29 of the head so that the openings occur between the posts 27 above the circular outer flange 25. For example, it has been found, working with a wire stock of about .132 inch in diameter, that a drill about .020 inch in greater diameter than the diameter of a circle including the surfaces 29 will be sufliciently large to remove the metal of the surfaces 29 without leaving burrs which are difiicult to remove by tumbling. Referring particularly to FIC- URES 811, it may be noted that the drill is extended to the bottom surface 32 in the head leaving considerable connecting metal between the stem 26 and the head itself. A window 33 is formed between each pair of posts 27 and the drill removes the metal along a circular bore 34 such that when viewed from the open end of the head there is visible clearance between the inner surface of the lower circular flange and the outer surface 35 of the flange 23 next to the stem 26.

Following the drilling operation, the dowel is ready to receive a resilient material molded about the head as illustrated in the dotted outline of FIGURE 6. The resilient material would take the form of a block 4t} which may be accurately shaped to the shape of the finished lift \b ut ordinarily is over-sized for trimming on the shoe ass'rnbly line. The material extends'into the longitudinal bore in the head and through each of the windows 33 so that 1 's mechanically locked into the head. The upper surfac 36 of the lower flange 25 provides a considerablearea rxsist-ing the pull which might be applied tending to remove tine material endwise frornthe dowel. Twisting of the materi'aLof the lift relative to the dowel is adequately resisted by the material extending through the'windows 33. The lift may-be worn down to the louter flange 25 without materially lessening the effectiveness of the heel lift. The posts 27 are sufficiently strong to support the weight of a lady resting directly on thei lower flange 25. I

The steps used to manufacture the dowel are primarily intended to be handled by automatic machinery. The cost of the dowel is thus held to a minimum and is 'competitive with other heel lift structures while providing a superior structure.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom, for some mpdifications will be obvious to those skilled inthe art.

We claim:

1. The method of preparing a ladies heel lift comprising the steps of: enlarging one end of a wire stock to provide an enlarged first flange at the extremity of one end of the stock and an enlarged head contiguous with the flange and having spaced portions extending longitudinally of the wire stock, but spaced inwardly from the outer extent of said intermediate portions; drilling lengthwise into said head past said first flange with a drill of suflicient diameter to remove material only from the interior of said head including the intermediate portions of said head, breaking through the outer extent of said intermediate portions to form a hollow head with lateral passages adjacent said first flange between the exterior and interior of the head, said spaced portions of said head connecting said first flange and said second flange and forming a cage structure for receiving a resilient material within and around said head beyond said second flange; and molding resilient material about the cage structure so that the molded resilient material will pass between the spaced portions and on either side of said first annular flange and about said second annular flange so that twisting of the material from the dowel is restricted by the passage of the resilient material through the spaced portions and axial pull of the material from the dowel is restricted by said first flange.

2. The method of preparing a ladies heel lift comprising the steps of: enlarging one end of a wire stock to provide a first flange at the extremity of one end of the stock and an enlarged head contiguous with the flange and having spaced portions extending longitudinally'of the dowel with the outer extent of said spaced portions generally aligned with the outer extent of said first flange and the outer extent of the intermediate portions of the head between said spaced portions spaced inwardly from the outer extent of said flange, and a second flange positioned between the head and said wire stock joining the head to the wire stock and extending outwardly from the wire stock with a generally radial upper surface immediately adjacent the wire stock; drilling lengthwise into said head past said first flange with a drill of suflicient diameter to remove material only from the interior of said head including the intermediate portions of said head, to form a hollow head with said first flange being annular and lfteral passages adjacent said first flange between the exterior and interior of the head, said spaced portions of said head connecting said first flange with the second flange and forming a cage structure having open windows of a size to pass molded material through the windows from the exterior to the interior of the cage, said window placement being adjacent the first flange so that the molded material passing through the windows may bear against the first flange to hold the material against end-wise withdrawal; and molding resilient material about the cage structure.

References Cited by the Examiner UNITED STATES PATENTS 1,699,953 1/ 29 Conant 264-27 3 1,829,022 10/31 Stevenson. 2,389,517 11/45 Labadie 29552.4 X 2,393,751 1/46 Chott 264--274 X 2,821,764 2/58 Leahy et a1. 264--273 X WHITMORE A. WILTZ, Primary Examiner.

Claims

1. THE METHOD OF PREPARING A LADIES'' HEEL LIFT COMPRISING THE STEPS OF: ENLARGING ONE END OF A WIRE STOCK TO PROVIDE AN ENLARGED FIRST FLANGE AT THE EXTREMITY OF ONE END OF THE STOCK AND AN ENLARGED HEAD CONTIGUOUS WITH THE FLANGE AND HAVING SPACED PORTIONS EXTENDING LONGITUDINALLYY OF THE DOWEL WITH THE OUTER EXTENT OF SAID SPACED PORTIONS GENERALLY ALIGNED WITH THE OUTER EXTENT OF SAID FIRST FLANGE AND THE OUTER EXTENT OF THE INTERMEDIATE PORTIONS OF THE HEAD BETWEEN SAID SPACED PORTIONS SPACED INWARDLY FROM THE OUTER EXTEND OF SAID FLANGE, AND A SECOND FLANGE POSITIONED BETWEEN SAID HEAD AND SAID WIRE STOCK JOINING THE HEAD TO THE WIRE STOP, SAID SECOND FLANGE HAVING A CONTINUOUS OUTER EXTEND SPACED OUTWARDLY FROM THE PERIPHERY OF THE WIRE STOCK, BUT SPACED INWARDLY FROM THE OUTER EXTENT OF SAID INTERMEDIATE PORTIONS; DRILLING LENGTHWISE INTO SAID HEAD PAST SAID FIRST FLANGE WITH A DRILL OF SUFFICIENT DIAMETER TO REMOVE MATERIAL ONLY FROM THE INTERIOR OF SAID HEAD INCLUDING THE INTERMEDIATE PORTIONS OF SAID HEAD, BREAKING THROUGH THE OUTER EXTENT OF SAID INTERMEDIATE PORTIONS TO FORM A HOLLOW HEAD WITH LATERAL PASSAGES ADJACENT SAID FIRST FLANGE BETWEEN THE EXTERIOR AND INTERIOR OF THE HEAD, SAID SPACED PORTIONS OF SAID HEAD CONNECTING SAID FIRST FLANGE AND SAID SECOND FLANGE AND FORMING A CAGE STRUCTURE FOR RECEIVING A RESILIENT MATERIAL WITHIN AND AROUND SAID HEAD BEYOND SAID SECOND FLANGE; AND MOLDING RESILIENT MATERIAL ABOUT THE CAGE STRUCTURE SO THAT THE MOLDED RESILIENT MATERIAL WILL PASS BETWEEN THE SPACED PORTIONS AND ON EITHER SIDE OF SAID FIRST ANNULAR FLANGE AND ABOUT SAID SECOND ANNULAR FLANGE SO THAT TWISTING OF THE MATERIAL FROM THE DOWEL IS RESTRICTED BY THE PASSAGE OF THE RESILIENT MATERIAL THROUGH THE SPACED PORTIONS AND AXIL PULL OF THE MATERIAL FROM THE DOWEL IS RESTRICTED BY SAID FIRST FLANGE.