US3040792A

US3040792A - Soft-face hammer

Info

Publication number: US3040792A
Application number: US53087A
Authority: US
Inventors: Robert F West; Walter H Robinson
Original assignee: Stanley Works
Current assignee: Stanley Works
Priority date: 1960-08-31
Filing date: 1960-08-31
Publication date: 1962-06-26
Anticipated expiration: 1979-06-26

Description

June 26, 1962 R. F. WEST ET AL 3,040,792

SOFT-FACE HAMMER Filed Aug. 51, 1960 FIG. I

FIG. 2

INVENTORS ROBERT E WEST By WALTER ROB/NSON WWCQ ATTO EYS United States Patent 3,040,792 SOFT-FACE HAMMER Robert F. West, Simsbury, and Walter H. Robinson, West Hartford, Comm, assignors to The Stanley Works, New Britain, Conn., a corporation of Connecticut Filed. Aug.'31, 1960, Ser. No. 53,087 7 Claims. (Cl. 145-36) The present invention relates to hammers of the type having relatively soft striking faces, generally known as soft-face hammers.

Hammers having striking tips or faces of yieldable or deformable material are used when it is desired to avoid inarring the surface of an article being struck. These tools employ a striking surface formed of a material softer than that being struck, and various materials, including plastics, leathers, soft metals, etc., have been proposed and utilized for this purpose. In order to obtain maximum efficiency in operation, it is desirable to be able to change the materials used for the striking tip so as to obtain a striking surface which is somewhat softer than the surface to be struck, but which is not unduly so.

It is an object of the present invention to provide a novel hammer structure having striking tips of relatively soft deformable material which are readily interchangeable, ruggedly mounted and free from tendency to loosen during use.

- Another object is to provide such a hammer having readily removable and interchangeable mounting sockets for firmly holding and supporting striking tips of resiliently deformable material without loosening during use.

It is also an object to provide such a hammer which is ruggedly constructed and wherein the handle is secured inthe head in a novel manner to prevent any twisting or looseness therebetween.

-A further object is to provide such a hammer having reversible striking tips so that either transverse face may be used and to provide resiliently deformable striking tips of a novel and superior design as to enable extended usage and ready reversibility and interchangeability.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

'FIG. 1 is an exploded perspective view of a hammer embodying the present invention with a portion of one tip mounting socket broken away to show internal structure;

FIG; 2 is an enlarged side elevational view of the assembled hammer in partial section to show internal structure; and

FIG. 3 is a sectional view along the line 3--3 of FIG. 2.

Referring to the drawings, a soft-face hammer embodying the present invention has a rigid metallic head 2 having a body portion 4 of generally cylindrical configuration with a handle mounting aperture 6 extending radially through the center thereof. Projecting outwardly from either end of the body portion 4 are threaded bosses 8, each of which has an eccentrically located recess 12 in its outer surface for a purpose to be described more fully hereinafter.

Engaged on each of the bosses 8 is a tubular tip mounting sleeve or socket 14 providing a generally cylindrical "ice ture extending through the socket. Intermediate the length of the tip receiving aperture 16, and preferably more closely adjacent the outer end thereof, is a circumferential internal rib 22 providing an abutment of reduced cross-section in the tip receiving aperture. Also, spaced about the inner surface of the socket are a plurality of short longitudinal grooves 24 which preferably extend into or through the internal rib 22, both for a purpose to be described fully hereinafter. To facilitate gripping and rotation of the sockets, the outer periphery is knurled or roughened as indicated by the numeral 25.

Securely mounted in the tip mounting aperture 16 of the socket 14 is a symmetrical striking tip 26 of deformable material dimensioned and configured to closely conform to the periphery of the mounting aperture 16 and having inner and outer transverse striking surfaces 27. Upon insertion of the striking tip 2-6 into the socket, the internal rib 22. deforms the tip and causes the tip material to lock behind it and prevent looseness during use. Some of the tip material extends into the longitudinal grooves 24 so as to form locking keys for the tip in the aperture 16 and eliminate any tendency for relative rotation of the tip in the socket aperture.

With resiliently deformable materials such as plastics, the tip 26 is merely forced into the socket 14 and the resiliently compressed material expands as it moves past the internal rib 22 until the inner face 27 of the tip bottoms in the aperture against the collar portion 1 8. Some of the tip material is'also forced into the longitudinal grooves 24 during the compression attendant to passage through the rib 22. This internal holding arrangement in the socket insures firm and constant retention of. the tip with substantial freedom from any tendency toward looseness or rotation.

As will be readily apparent from the drawing, the close contact of the peripheral wall of the socket 14 with the peripheral surface of the tip 26 provides a reinforcement and lateral support and prevents excessive radial deformation as well as providing a path for the transmission of shock and stress into the body portion of the head where the forces can be more readily dissipated, thus materially extending the life of the tip. Preferably the tip receiving aperture is on the order of one-half the length of the tip to as to provide optimum characteristics of support.

Upon being subjected to the percussive forces during initial use, some of the plastic material of the inner face 27 of the striking tip 26 will be extruded or forced into the eccentrically located recess 12 in the boss surface 10 to provide a self-forming dowel pin 28 which elfectively prevents inadvertent loosening of the threaded connection between boss and mounting socket during use. However, to disconnect the members, it is only necessary to apply suflicient rotational pressure to shear or break the dowel pin 28.

Although any relatively soft and deformable material may be used for the striking tips of the present invention, it is preferable to employ resiliently deformable materials having the desired degree of hardness since permanent deformation of the striking face or the body of the tip is thereby avoided. Such materials are particularly desirable since the tip is desirably reversible in accordance with the preferred embodiment. Exemplary of such resiliently deformable materials are natural rubbers and various synthetic plastics such as nylon, synthetic rubbers, and cellulose esters.

The preferred configuration for the striking tip is illustrated in the drawings and is one which has proven to be highly superior in extended testing. As illustrated, the tip is symmetrical and generally cylindrical, with a cylindrical body and convexly curvilinear striking faces 27 at both ends. Both striking faces 27 are similarly determined by two radii, a large radius being used for the striking surface which comprises the major portion of the face and a small radius along the periphery of the striking surface to blend smoothly from the large radius into the side of the Striking tip. The length of the tip is most desirably on the order of the width of the tip, and preferably somewhat less. This configuration has proven particularly advantageous in absorbing and dis-. tributing the shock and stress throughout the body of the tip and to the head of the hammer through the contact with the sides of the socket and through the inner curvilinear surface which butts against the boss 8. The convexly curvilinear configuration of the striking face disposed inwardly of the socket ensures direct contact between the crest of the tip and the center or boss of the hammer head so that the major transmission of impact forces occurs in this area. This construction avoids major transfer of impact force at a point offset from the center of the two elements and the attendant increase in stresses, and has been found to provide a highly effective, long-lived soft-face hammer.

-As a specific example of a tip construction which has proven highly advantageous, a cylindrical tip is formed with an axial length of 1 inches and a diameter of l.341.38 inches depending upon the durometerrange is desired, the diameter decreasing with increase in hardmess. The major transverse surface is determined by a radius of /2 inches and the blending radius is $4 inch.

Thus, the tip mounting sockets containing tips of various hardness may be readily interchanged in accordance with the needs of the work. When one striking surface of the tip becomes worn, the tip itself may be reversed in the socket by unthreading the rocket from the boss and expelling the tip from the socket by means of the tool inserted through the threaded aperture 20 in the collar 18, after which the tip is reversed and driven back into the socket apertureld so as to expose the unworn str k f Ih e handle 36 is securely mounted in the eye 6 of the head so as to prevent any twisting or looseness therebetween by means of several features. As shown in FIGS. 2. and 3, the mounting eye or aperture 6 tapers inwardly from both ends to provide a portion of reduced crossscti n nterme iate n length and a plurality of Short longitudinal grooves 38 are broached into the head about the periphery of the eye at this portion of reduced cross section so that when'the handle 36 is driven into the eye 6, some of the wood enters into the grooves 38 and locks the handle from rotation therein. A wedge 49 is driven into the terminal end of the handle to deform and eX- pand the terminal portion of the handle into engagement with the periphery of the eye 6 above the portion of reduced c ssn- AS. Will be readily appreciated, the weight of the hammer can be varied by selection of the dimensions and material used for the head of the hammer and to some degree by the material and dimensions for the sockets. Because of the stresses and shock encountered during use of the hammer, the head and sockets are preferably fabricated from metal to provide optimum durability. When using hammers of heavier weight, the tips utilized therein are preferably increased dimensionally in proportion.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

We claim:

1. In a soft-face hammer, the combination comprising a head having a handle receiving aperture therein and tubular rigid sleeves at its ends each providing tip mountingapertlil' s, Said tubular sleeves each having an internal portion intermediate the length of said aperture projecting inwardly thereof to define an aperture of lesser crosssection than that of the outer end thereof, the surfaces of said internal portion extending longitudinally of said sleeve being inclined to provide ramp surfaces; and symmetrically configured striking tips of deformable material removably seated in each of said tip mounting apertures, said tips extending outwardly of said tip mounting apertures and having the side surfaces in close-fitting engagement with the side surfaces of the tip. mounting apertures, said tips having end surfaces of convex-1y curvilinear configuration with the crest of the inner end surface seated firmly against said hammer head, said sleeve internal portion being embedded in and deforming the tip material to firmly lock the tip into said tip mounting aperture against inadvertent release, said inclined rampsurfaces providing gradual compression of the tip material for longitudinal movement of the tip relative to said sleeve internal portion, said'tips being releasable from said sleeve internal portions and reversible in said sleeves to provide a pair of striking surfaces each of convexly curvilinear configuration.

2. A hammer in accordance with claim 1 wherein said tip receiving apertures of the tubular sleeves are cylindrical in configuration and said tips are fabricated from a resil, iently deformable synthetic plastic material and are of generally cylindrical configuration with said convexly curvilinear striking surfaces beingdetermined by two radii, a large radius providing a smooth curve over substantially the entire striking surface and a relatively small radius smoothly blending from said large radius into the side of the tip.

3. In a hammer having striking faces of resiliently deformable material, the combination comprising a metallic head having tubular sleeves at each end providing tip mounting apertures with an internal rib intermediate the length thereof and longitudinal grooves in said rib; and striking tips of resiliently deformable material removably seated in each of said apertures in close-fitting engagement with the periphery of the tip mounting aperture, said internal rib being embedded in and deforming the tip material to firmly lock the tip into said tip mounting aperture against inadvertent release, portions of said tip material extending into said longitudinal grooves to prevent rotation in said tip mounting aperture.

4. A hammer having striking faces of resiliently deformable material comprising a cylindrical metallic head having a handle receiving aperture in the center thereof and threaded bosses projecting outwardly from the ends thereof; a handle having an end portion securely engaged in said handle receiving aperture; a pair of cylindrical tubular tip mounting sockets each providing a tip mount ing aperture extending inwardly from one end thereof and a collar at the other end thereof with a threaded aperture therein threadably engaged upon said bosses, each of said tubular sockets having an internal circular rib projecting radially inwardly of said tip receiving aperture intermediate the length thereof and a plurality of longitudinal grooves in said rib; and generally cylindrical striking tips of resiliently deformable material removably seated in each of said tip mounting apertures, each of said tips having its peripheral surface in close fitting frictional engagernent with the peripheral surface of the tip mounting aperture and said internal rib of the socket being embedded in and deforming the tip to firmly lock said tip in the socket against inadvertent release, and portions of said tip extending into said longitudinal grooves to prevent twisting movement.

5. A hammer in accordance with claim 4 wherein said striking tips are symmetrical and reversible in said sockets, said tips having curvilinear striking faces determined by two radii, a large radius providing a smooth curve over substantially the entire striking face and a relatively small radius smoothly blending from said large radius into the side of the tip. V

6. A hammer having striking faces of deformable material comprising a metallic head of generally cylindrical configuration having a handle receiving aperture extending therethrough normal to its axis and having threaded bosses extending outwardly from its ends, each of said bosses having an eccentrically located recess in the outer surface thereof; a handle having an end portion secured in said aperture; a pair of generally cylindrical tubular tip mounting sockets each providing a generally cylindrical tip receiving aperture extending inwardly from one end thereof and a collar portion at the other end thereof with a threaded aperture engaged on said threaded bosses, each of said tubular sockets having an internal circular rib projecting inwardly of said tip receiving aperture intermediate the length thereof and having longitudinal grooves spaced about the inner periphery thereof extending through said internal rib; and generally cylindrical striking tips of resiliently deformable material seated in said tip receiving apertures in close fitting engagement with the periphery of the apertures, said tips being symmetrically configured and having curvilinear striking faces defined by two radii, said internal rib extending into and deforming the resilient material of the tip to firmly =lock said tip in said socket against inadvertent release and portions of the tip extending into said longitudinal grooves to prevent rotation of the tip in the socket, the inner face of each of said tips having a portion extending into said eccentrically located recess in the face of the boss to lock said socket against inadvertent rotation on said boss.

7. A hammer having striking faces of resiliently deformable material comprising a metallic head of generally cylindrical configuration having a handle receiving aperture extending therethrough normal to its axis and having threaded bosses extending outwardly from its ends, each of said bosses having an eccentrically located recess in the outer surface thereof, said handle receiving aperture being of generally circular cross-section and tapering from exit and entrance ends to an intermediate portion of reduced cross-section and having longitudinal- 1y extending grooves spaced about its periphery in said portion of reduced cross-section; a handle having an end portion secured in said aperture with portions extending into said longitudinally extending grooves to prevent twisting movement thereof in said head; a wedge in said handle end portion at the exit end of said aperture forcing said handle into tight engagement with the tapering side walls of the exit end of the handle receiving aperture; a pair of generally cylindrical tubular tip mounting sockets each providing a generally cylindrical tip receiving aperture extending inwardly from one end thereof and a collar portion at the other end thereof with a threaded aperture engaged on said threaded bosses, each of said tubular sockets having an internal circular rib projecting inwardly of said tip receiving aperture intermediate the length thereof and having longitudinal grooves spaced about the inner periphery extending through said internal rib; and generally cylindrical reversible striking tips of resiliently deformable material seated in said tip receiving apertures in close fitting engagement with the periphery of the aperture, said tips bein'g symmetrically configured and having curvilinear striking faces defined by two radii, said internal rib extending into and deforming the resilient material of the tip to firmly lock said tip in said socket against inadvertent release and portions of the tip extending into said longitudinal grooves to prevent rotation of the tip in the socket, the inner face of each of said tips having a portion extending into said eccentrically located recess in the face of the boss to lock said socket against inadvertent rotation on said boss.

References Cited in the file of this patent UNITED STATES PATENTS 460,115 Colton Sept. 29, 1891 2,518,059 Pemmerl Aug. 8, 1950 2,525,429 Seip Oct. 10, 1950 FOREIGN PATENTS 5,648 Great Britain 1911 607,896 Great Britain Sept. 7, 1948 23,061 Australia Jan. 7, 1936 776,284 Great Britain June 5; 1957