US3821973A

US3821973A - Replaceable hammer tip

Info

Publication number: US3821973A
Application number: US00389234A
Authority: US
Inventors: J Carmien
Original assignee: Nupla Corp
Current assignee: Nupla Corp
Priority date: 1973-08-17
Filing date: 1973-08-17
Publication date: 1974-07-02
Anticipated expiration: 1991-07-02

Abstract

A replaceable hammer tip which is molded to incorporate as an integral part of its body the upper portion of an hexagonal head bolt of standard manufacture and a molded plastic stud lock. The stud lock has an hexagonal opening within which the head of the bolt is mounted to prevent rotation of the bolt with respect to the stud lock. The shank of the bolt extends through the center of the stud lock and protrudes from the lower edge of the tip for removable attachment to the hammer. The stud lock has a plurality of radially directed fins which engage the body of the tip to prevent rotation of the stud lock and a circular top which prevents vertical movement of the stud lock.

Description

United States Patent [191 Carmien REPLACEABLE HAMMER TIP [75] Inventor: Joseph Allen Carmien, Sun Valley,

Calif.

[73] Assignee: Nupla Corporation, Sun Valley,

Calif.

22 Filed: Aug. 17, 1973 211 App]. No.1 389,234

[52] US. Cl. 145/29 A, 145/36 [51] Int. Cl B25d l/02 [58] Field of Search.... 145/29 A, 29 C, 29 R, 29 B, 145/29 D, 36

[56] References Cited UNITED STATES PATENTS 2,601,294 6/1952 Jahn et a1 145/36 2,989,101 6/1961 Carmien 145/29 A 2,989,102 6/1961 Del Pesco et al 145/29 A 3,088,506 5/1963 Bianchini 145/36 [111 3,821,973 [451 July 2,1974

Primary ExaminerAl Lawrence Smith Assistant ExaminerJ. T. Zatarga Attorney, Agent, or FirmRobert C. Comstock [57] ABSTRACT A replaceable hammer tip which is molded to incorporate as an integral part of its body the upper portion of an hexagonal head bolt of standard manufacture and a molded plastic stud lock. The stud lock has an hexagonal opening within which the head of the bolt is mounted to prevent rotation of the bolt with respect to the stud lock. The shank of the bolt extends through the center of the stud lock and protrudes from the lower edge of the tip for removable attachment .to the hammer. The stud lock has a plurality of radially directed fins which engage the body of the tip to prevent rotation of the stud lock and a circular top which prevents vertical movement of the stud lock.

8 Claims, 5 Drawing Figures REPLACEABLE HAMMER TIP BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a replaceable hammer tip and more particularly to the attaching means for removably securing the tip to a hammer.

2. Description of the Prior Art Prior to the present invention, replaceable hammer tips were provided with screw threaded attaching means-which comprised specially manufactured metal inserts. Because of the need of a large head area required to preclude rotation within the insert top compared to the threaded stud diameter, the inserts were expensive and manufacturers of metal fastening devices were not interested in making them. The special inserts have accordingly become increasingly expensive and increasingly difficult to obtain. They also require special metal forming molds which are relatively expensive to make and operate, particularly in comparison with plastic molding. Further, the metal inserts have limitations as to the size and configuration which can be produced from the steel bar size required for the threaded shank, hence less than the best anchor effects result. I

SUMMARY OF THE INVENTION The primary object of the present invention is to pro vide a replaceable hammer tip attaching means which does not require a specially manufactured metallic insert and which instead utilizes standard fastening devices such as hexagonal head bolts which are freely available on the market at an extremely low price.

Another object of the invention is to provide a stud lock for hammer tips having means for holding a standard bolt against rotation within the stud lock and also having means for holding itself against rotation with respect to the hammer tip.

A further object of the invention is to provide a replaceable hammer tip which is more economical to manufacture than those which are now in use.

The invention also comprises such other objects, advangages and capabilities as will later more fully appear and which are inherently possessed by the invention.

While there is shown in the accompanying drawings a preferred embodiment of the invention, it should be understood that the same is susceptible of modification I and change without departing from the spirit of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a replaceable hammer tip in use, with the hammer shown in phantom lines;

FIG. 2 is a bottom plan view of the tip, taken on line 22 of FIG. 1;

FIG. 3 is an inverted sectional view of the tip taken on line 3-3 of FIG. 1, with the bolt shown in elevation;

FIG. 4 is an inverted isometric view of the stud lock with the bolt partially inserted therein;

FIG. 5 is a bottom plan view of the stud lock.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment which has been selected to illustrate the invention comprises a replaceable hammer tip having a body 10 which is customarily formed by injection molding of various types of plastic materials, depending upon the particular tip characteristics which are desired. For example, vinyl may be used to provide a soft, resilient, rubber-like tip. Nylon provides a tip which is harder and more heat resistant. Commerce and industry require a wide range of hardnesses from 'as soft as flesh to as hard as brass.

Attaching means for removably securing the tip to the hammer are incorporated within the body 10 at the time the tip is molded. Such attachment means preferably comprises a conventional standard bolt 11, which is preferably zinc plated. The bolt 11 has an hexagonal head 12 and a screw threaded shank 13. Such bolts are commonly available on the market at an extremely low price as articles of common manufacture available from a number of different competitive sources of supp y- As a coupling means between the bolt 11 and the tip body 10, a stud lock 14 is utilized The stud lock 14 is preferably formed of relatively strong molded plastic material such as fiberglass reinforced nylon. Other hard, heat resistant injection molding compounds may be used such as vinyl and others known to those skilled in the art. The material used in forming the stud lock 14 should be hard and strong so that the stud lock will not bend or break in use, particularly in resisting rotation. The particular material selected depends on the character of the hammer tip material in which it will be used. The material used must also be heat resistant because it is subjected to a second molding operation when it is incorporated within the body of the tip.

The stud lock 14 has a flat circular top 15, in the center of which an hexagonal opening 16 is provided. The opening 16 is formed complementarily to the shape and size of the hexagonal head 12 of the particular bolt 11 with which it is used. The bottom of the bolt head 12 fits against the bottom of the opening 16. Beneath the hexagonal opening 16 is a concentric circular opening 17 which is dimensioned to receive and fit around the upper portion of the shank 13 of the bolt 11. The stud lock 14 is accordingly dimensioned to receive and securely fit around the bolt 11 in such a manner that the bolt 11 cannot be rotated with respect to the stud lock 14.

Viewed from the outside, the stud lock 14 has a plurality (six in the embodiment shown) of spaced radially directed fins 18 which are disposed directly beneath the top 15 and which extend to its outer periphery. The inner edges of the fins 18 terminate at a lower circular member 19 which extends around the lower edge of the circular opening 17. Beneath the lower circular member 19 are three spaced downwardly directed arcuate skirts 20 which also engage the shank 13 of the bolt 11 and provide accurate vertical positioning of the bolt 11 and stud lock 14 within the body 10. The skirts 20 also control the length of exposed thread on the shank 13 to meet customer requirements.

The stud lock 14 includes an integral hexagonal portion 21 which encloses the lower portion of the hexago- All of the portions of the stud lock 14 which have been described above are actually integral portions which are formed simultaneously in a single conventional plastic injection molding operation.

In forming a replaceable hammer tip, a standard bolt 11 of suitable size and configuration is first mention in a previously molded stud lock 14, with the bolt head 12 disposed within the hexagonal opening 16 and the bolt shank 13 extending through the circular opening 17. Both are then placed in a plastic mold in which the body is molded around the stud lock 14 and around the upper part of the bolt 11. The completed tip comprises a body 10 having the lower screw threaded end of the bolt shank 13 protruding from its lower edge as an attaching means for removably securing the tip to a hammer. The remainder of the bolt 11 and the entire stud lock 14-are completely enclosed within the tip body 10..

The hexagonal head 12 of the bolt 11 is securely held against rotation within the stud lock 14 by its engagement with the hexagonal opening 16. The fins 18 act to prevent any rotation of the stud lock 14 with respect to the body 10. The top of the stud lock 14 acts to prevent any vertical movement of the stud lock 14 with respect to the body 10.

The result is that there is secure locking engagement between the bolt 11 and body 10, whereby neither rotation nor vertical movement is possible. The invention accordingly provides a means whereby a standard bolt may be used as an economical mounting means for a replaceable hammer tip.

While a bolt having an hexagonal head is shown and described, it will be obvious that any other type of irregular head configuration may be used. It will also be obvious that the particular shape of the tip itself makes no difference in the operation of the invention.

I claim:

1. A replaceable molded hammer tip comprising a bolt of standard manufacture having a head of irregular configuration and an externally screw threaded circular shank, a stud lock having an irregular opening in the upper portion thereof formed complementarily to and fitting around the head of said bolt, said stud lock having a circular opening through which the shank of said bolt extends, said hammer tip being molded around said stud lock and around the upper portion of said bolt to provide a tip having a body with the lower portion of the screw threaded shank protruding therefrom, said stud lock having means engaging the body of said tip to prevent rotational movement of said stud lock with respect to the body of said tip.

' 2. The structure described in claim 1, said bolt having an hexagonal head and said stud lock having an hexagonal opening.

3. The structure described in claim 2, said engaging means between said stud lock and the body of said tip comprising a plurality of radially directed fins formed as an integral part of said stud lock.

4. The structure described in claim 3, said stud lock having means for preventing vertical movement of said stud lock with respect to said body.

5. The structure described in claim 4, said stud lock having a circular top, said fins being disposed beneath said top, said stud lock having open spaces between said fins and beneath said top, whereby the lower end of said top forms a locking engagement with the body of said tip to prevent downward vertical movement of said stud lock with respect to the body of said tip.

6. The structure described in claim 5, the head of said bolt and the entire stud lock being enclosed within the body of said tip so that only the lower end of said screw threaded shank protrudes from said tip.

7. The structure described in claim 6, said stud lock being formed of fiberglass reinforced nylon.

8. The structure described in claim 7, said bolt being zinc plated.

Claims

2. The structure described in claim 1, said bolt having an hexagonal head and said stud lock having an hexagonal opening.

8. The structure described in claim 7, said bolt being zinc plated.