US3030989A - Hammer - Google Patents

Description

April 24, 1962 B. J. ELLIOTT HAMMER Filed Jan. 25, 1961 IFIIG-l TOR. ELLIOTT E 5 g J D R A N R E B rm/(war Fuel- 3 United States atent This invention relates to an improved hammer designed to reduce rebound and also the shock transmitted through the handle to the user.

The improved hammer is particularly intended for use in driving studs, pins, or other fasteners into hard surfaces such as concrete or brickwork, although it is not limited thereto.

Ordinary hammers can be very tiring to use, particularly when used for heavy work such as driving fasteners into hard surfaces. This is to a great extent caused by the shock transmitted to the user through the handle on the impact of the tool and also the natural tendency on the part of the user to curb rebound. To overcome this difliculty, hammers have been made with springs in head or handle and even with movable pieces in the head, but these prior devices have the other disadvantages of breaking down too easily and too soon, or of either absorbing too much energy at the expense of the useful work or of rebounding too much.

The present invention has for its object to provide an improved construction of hammer in which the above disadvantages are, to a great extent, overcome.

This object is achieved, according to the invention, by providing a hammer comprising a tubular holder connected to a handle, a resilient shock-absorbing sleeve, also of tubular shape, fitted within said tubular holder and a striker member supported by said resilient sleeve so as to be resiliently movable in relation to the holder on the impact of the tool to thus reduce the shock transmitted to the user through the handle of the tool. Be-

tween the rigid holder and rigid inner member the tough resilient sleeve is compressed highly enough radially to bond these parts together at least frictionally.

Preferably, the, striker member also has a shoulder which, on the impact of the tool, cooperates with a mating interior face at an end of the holder and compresses an extension at the end of the resilient sleeve against the end of the tubular holder to provide additional cushioning or shock-absorbing characteristics.

The invention is more fully described aided by reference to the accompanying drawings wherein:

FIG. 1 is a sectional view of a hammer according to the invention.

FIG. 2 is a section on line II-II'of FIG. 1.

FIG. 3 is an enlarged detail view showing the action of the shoulder of the striker member in compressing the end of the resilient sleeve; the parts being shown only partially.

As is shown in these views, the improved hammer comprises a tubular holder 1 connected to the handle 2, a resilient shock-absorbing sleeve 3, also of tubular shape, fitted within said tubular holder. and a striker member 4 supported by said resilient sleeve. The tubular holder 1 is of cylindrical form and is welded as at 5 to the handle 2 which is also preferably of tubular form.

The resilient sleeve 3 is formed of rubber, synthetic rubber or elastomer having a high degree of elasticity and is tightly fitted within the tubular holder 1 to closely hug the interior wall of the latter. It is slightly longer than the tubular holder so that its lower end protrudes somewhat from the lower end of the holder as indicated at 6. It may also protrude slightly at the upper end as at 7. This allows for sleeve rolling up the slope at 11,

3,036,989 Patented Apr. 24, 1962 radial squeezing and creation of a temporary flange bulging and rise in sleeve squeeze at 6.

The striker member 4 comprises a head 8 and an upwardly extending shank 9 which fits tightly within the resilient sleeve 3. The shank is of lesser diameter than the head 8 which may be of a diameter substantially equal to the external diameter of the tubular holder. The junction between the head 8 and the shank 9 is constituted by a shoulder 10 which is in the form of a curved or sloped surface 11 meeting at 16 the head 8 abruptly but merging smoothly into the shank 9.

The resilient sleeve 3 may be treated on both its exterior and interior surfaces 18 and 19, respectively, with a suitable adhesive or cementing agent so that such surfaces are united to the interior surface of the holder 1 and the exterior surface of the shank 9, except adjacent the ends at 6 and 7.

In use, the resilient shock-absorbing sleeve 3 reduces the shock transmitted to the user through the handle 2 on the impact of the tool. In effect, the resilient sleeve is elastically distorted or elongated by the shank 9 which moves axially in relation to the tubular holder in the direction of the arrow in FIG. 1 on impact. The curved or sloped surface 11 between the head 8 and the shank is also forced into the lower end 15 of the holder with an increasing wedging action to compress the lower end 6 of the resilient sleeve against the lower end of the tubular holder as shown in FIG. 3. Flanging occurs.

The cushioning, or shock-absorbing actions as above described considerably reduce the shock transmitted to the user through the handle of the tool and also effect a substantial reduction of the rebound of the tool so that the tool is much less tiring to use than conventional type hammers.

Shoulder it} extends outwardly to overlap end 15 at least in part. Extended end 6 bulges outwardly from holder 1.

The handle 2 may be provided with a shock-absorbing rubber hand grip 12 to further reduce shock and the striking face 13 of the heads may be of convex shape. The upper portion 14 of the shank 9 may extend a substantial distance beyond the upper end ofthe resilient sleeve to give the tool desired Weight and the extended part may, if desired, be slightly tapered.

The main shock absorption occurs in the hammer head because the elongated sleeve 3 undergoes not only shear between its surfaces 18 and 19 but also more squeezing. Adjacent extension 6 during the impact stroke progressively increased radial squeezing occurs on an ever increasing slope at 11. Finally at the end of the stroke there is created an expandable exterior flange at 6 undergoing endwise compression between shoulder 10 and the holder end 15.

The foregoing is a description of what is now believed to be a preferred embodiment. Those skilled in the art will understand that various changes and modification can be made without departing from the spirit and scope of this invention as set forth in the appended claims.

The claims defining the invention are as follows:

1. A hammer comprising a tubular holder connected to a handle, a resilient shock absorbing sleeve of tubular shape fitted within said holder, and a striker member supported by said sleeve whereby said striker is resiliently movable in relation to said holder on impact to reduce the shock transmitted through said handle, a sleeve end protruding out of an end of said holder. said striker having a shoulder which on said impact compresses said sleeve end against said holder end to provide additional shock absorbing characteristics, and wherein the shoulder has a tapering sloped surface which, on said impact, is forced into the end of the holder with a wedging action aos ess Q to compress said end of said resilient sleeve against said end of the tubular holder.

2. A hammer comprising a tubular holder connected to a handle, a resilient shock absorbing sleeve of tubular shape fitted within said holder, and a striker member supported by said sleeve whereby said striker is resiliently movable in relation to said holder on impact to reduce the shock transmitted through said handle, a sleeve end protruding out of an end of said holder, said striker including a head and a shank extending from said head to fit Within said sleeve, and wherein the shank is of lesser diameter than the head and the junction between the head and the shank is constituted by a shoulder in the form of a curved concave surface which, on said impact, is forced into the end of the holder with a wedging action to compress said end of said resilient sleeve against said end of said tubular holder.

3. A hammer as claimed in claim 2 wherein the curved concave surface meets the head flaredly but merges smoothly into the shank.

4. A hammer comprising a tubular holder connected to a handle, a resilient shock absorbing sleeve of rubber or like elastomer of tubular shape fitted within all of said holder, and a striker member supported within said sleeve whereby said striker is resiliently movable in relation to said holder on impact to reduce the shock transmitted through said handle, a sleeve end protruding out of an end of said holder, said striker including an enlarged head and a reduced shank extending from said head to fit within said sleeve and form with said head a shoulder which on said impact compresses said sleeve end against said holder end to provide additional shock absorbing characteristics, and wherein the end of the resilient shockabsorbing sleeve protruding from the end of the holder between said holder end and the shoulder thereby forms an expandible bulge.

References Cited in the file of this patent UNITED STATES PATENTS

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