US2806230A

US2806230A - Striking tool head and handle combination

Info

Publication number: US2806230A
Application number: US454936A
Authority: US
Inventors: Mesko Adam
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-09-09
Filing date: 1954-09-09
Publication date: 1957-09-17
Anticipated expiration: 1974-09-17

Description

.A. MESKO 2,806,230

STRIKING TOOL HEAD AND HANDLE COMBINATION Sept 17, 1957 Filed Sept. 9, 1954 Q INVENTOR.

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United States Patent STRIKING TOOL HEAD AND HANDLE COMBINATION Adam Mesko, Lorain, Ohio Application September 9, 1954, Serial No. 454,936 1 Claim. (Cl. 7-9) This invention relates to striking tools having forged metal heads and replaceable wooden handles such, for example, as claw, ball peen, sledge, and chipping hammers, and hatchets, axes and the like, and. particularly to improvements in the eye or handle accommodating passage of the head and the relation of the passage walls and handle which improvements relieve the handle from the imposition thereon by the headof deleterious concentrated stresses, reduce the shock transmitted from the head through the handle to the hand of the operator, and facilitate installation of a handle. 7

For the purposes of illustration, the invention will be described as applied to a conventional claw hammer comprising a forged one piece metal head and a. wooden handle accommodated in an eye or passage in the head, the application of the invention to other types of striking instruments being readily apparent from the illustrative example.

The conventional type of claw hammers employing a forged metal head and wooden handle comprises generally an elongated one piece metal head, one end of which is arranged for striking and driving a nail and the opposite end of which is bifurcated and shaped in the form of a pair of curved claws for pulling a nail. About midway between its opposite ends, the head is provided with an eye or passage which extends transversely through the head. Quite generally the head has an integral shank portion which extends transversely of the head generally axially of the passage at one side of the head, and the eye or passage is continued from the opposite or outer side of the head entirely through the head and shank. This affords a relatively longer passage for accommodating the outer or joining end portion of the handle. Usually the cross section of this eye or passage is rectangular, having its longer dimension extending from the front or driving end of the head toward the rear or claw end of the head. In general, also, the handle is somewhat greater in dimension in a direction forwardly and rearwardly of the head than transversely of the head.

In the prior hammers, the interior wall defining the eye or passage intersect the edges of the head or shank at the entry end of the passage at an abrupt angle. Thus, when using the hammer to drive nails, the head tends to rotate about'an'axis extending transversely of both the head and of the handle axis. Consequently the rear face of the handle is stressed against the sharp edge formed by the intersection of the rear "margin of the passage wall and the inner end of the shank portion. When pulling a nail, the forward face of the handle is stressed against the sharp edge formed by the intersection of the forward margin of the passage and the inner end of the shank portion. Both of these stresses are concentrated along a line, instead of an appreciable area of contact. These concentrated stresses cause cutting and destruction of the fiber of the handle at the point of contact of the handle at the sharp edges, thus weakening the handle at the point where the greatest stress occurs and greatest strength is desired.

or C 2,806,230

Patented Sept. 17, 1957 Thus, in all uses of the handle, the extraneously applied forces tend to rock the handle forwardly and rearwardly of the head about the said sharp forward and rearward edges as fulcrums, respectively.

The principal object of the present invention is to provide a striking tool head and handle combination in which the walls defining the entry portion of the handle receiving passage are configured so as to eliminate the concentration of the stresses and forces along a line of contact between the handle and the head at the inner limits of the head.

A more specific object is to provide at the entry portion of the passage of the head, marginal wall portions which begin a short distance inwardly from the entry end of the passage, are tangent .to the passage walls at their point of beginning, are convex toward the axis of the-passage and curve gradually outwardly toward the entry end of the passage about axes which are parallel to their associated passage walls and lie in a plane normal to the axis of the passage.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings, in which:

Figure l is a side elevation of a claw hammer embodying the principles of the present invention, part thereofbeing shown in section for clearness in illustration;

Figures 2 and 3 are sectional views taken on the lines 2-2 and 3-3, respectively, of Figure l; and

Figure 4 is a side elevation of the hammer illustrated in Figure 1, showing in dot-dash lines the deflection of the handle when the hammer is used for pulling nails, part of the head and handle being shown in section for clearness in illustration.

Referring to the drawings, the hammer comprises a one piece forged metal head 1 having a driving portion 2 at what hereinafter will be termed its front or forward end and a claw portion 3 at its opposite or rear end. Between its ends, the head is provided with an eye or passage 4 which extends transversely of the head. The head 1 has a shank portion 5 which extends laterally from the same side of the head as the handle at the location of the passage 4. The passage 4 is continued through the shank portion 5 as to increase the length of the passage 4 and aiford a larger area of contact between the outer end of the handle and the head.

The passage 4 is of the conventional cross sectionalshape for the particular tool and accommodates a wood handle 6 which preferably is fitted into the passage with a drive fit further tightened by means of the usual wedge 7.

The present invention is concerned particularly with the inner or entry end of the passage 4 and its relation to the handle as will now be described.

At the entry end of the passage 4, indicated generally at 8 are peripheral marginal wall portions defining the entry end of the passage 4. These marginal portions begina short distance from the entry end of the passage 4, and are tan-gent to the associated passage walls at their juncture therewith. They are convex toward the axis of the passage and curvilinear about axes parallel to their associated passage walls and lying in a plane normal to the axisof the passage. Thus they curve out-' peripheral marginal portion 13 and each of the side walls 11 has a peripheral marginal portion 14.

Each marginal portion, at its inner limit where it joins its passage wall is substantially tangent to its associated interior wall of the passage and curves'from its juncture therewith gradually outwardly toward the entry end of the passage. The marginal portion 12 is convex toward the axis of the passage 4, is curved about an axis which is not only parallel to the front wall 9 but lies in a plane extending 90 to the axis of the passage. While exact tangency is not required at the juncture of each wall and its curved marginal portion, it is much preferred, the important factor being that there must not be any appreciable abrupt angle formed at the juncture of the passage walls and marginal walls which would result in a line contact between the handle and the head at the entrant end of the head passage 4 and such as is present at the juncture of the passage walls and inner edges of the shank portion in conventional hammers or as in United States Patent No. 2,340,619, issued to L. Schwarzmayr on February 1, 1944, where marginal portions at the entry end of the eye or passage of the hammer head are planar and intersect at an abrupt angle with the planes of their associates passage walls.

Such angularly related surfaces are to be avoided.

In the present application the margins are preferably curved on a radius approximately equal at least as great as the thickness of the metal to the point of tangency.

Referring to Figure l, for example, the point of tangency may be as indicated at and the radius of the curved marginal portion 12 is preferably at least equal to the thickness of the metal of the shank portion at this location. A greater radius may be used, the important feature being that abrupt intersections of surfaces forming sharp corners or edges or about which the handle would be stressed in line contact with the head are eliminated.

The

marginal portions

13 and 14 are correspondingly related to their associated walls of the passage 4. Of course the passage 4 may be other than rectangular in cross section but in any event the general relation between the margin at any portion and the wall at any portion is maintained.

The advantages of the present structure can be appreciated by reference to Figure 4 in which the hammer is shown pulling a driven nail N, the head of the hammer resting against a floor F.

In order to pull the nail, the handle 6 is pushed or pulled to the left in Figure 4. Assuming a heavy force is exerted and the nail oflfers heavy resistance, the handle is deflected to the left in the direction indicated by the arrow to a position such as indicated in dotted lines. When this stress is exerted the handle, since its outer end is firmly gripped and enclosed in the passage of the head, tends to bend or deflect where connected to the head.

. Due to the curved margin 12, the handle does not rock or bend about a sharp edge .as a fulcrum but about the rounded margin. Instead it has a greater area in contact with the head and a better distribution of the stress imposed by the head on the handle 6, at the general location of greatest stress. Thus concentrated line contact between the head and handle is eliminated and thehandle can compress somewhat over a rounded of the handle, which aflfords a substantial area of contact and a distributed stress. This results in a more general curvature of the handle adjacent its head and is distributed instead of abrupt flexure across a sharp fulcrum.

The curvature of the margins is carried sufficiently far outwardly from the axis of the passage 4 to accommodate the handle against a curved surface at maximum deflection of the handle relative to the head.

correspondingly, when the nail is driven by the hammer, the similar relation occurs between the handle and the curved margin 13. Again the relation occurs if the handle is used for pounding or prying from either side.

Further, since the handle is not stressed across the sharp edge, its fibers are not cut .and destroyed and as a combined result of the preservation of the fibers and the distribution of the stress, the life of the handle is greatly increased.

Aside from these beneficial functional relations between the handle and the head due to the curvilinear margins, the margins facilitate forging as it is much easier to forge curved margins than provide the abrupt angle between the end wall surfaces of the shank and the surface without cutting so that the contact between the 6 handle and the margin has a substantial width, endwise inner wall surfaces of the passage 4.

The curved margins facilitate insertion of the handle which preferably is slightly oversized relative to the passage 4 so that when driven into place it will be retained more tightly.

Having thus described my invention, I claim:

In a claw 'hammer head comprising an elongated onepiece forged metal head having a driving portion at its forward end, a claw portion at its rearward end, and a shank extending transversely of the head at a location intermediate said ends, and having a through passage which extends from the outer end of the shank entirely through the shank endwise of the shank and continues through the head transversely of the head, and which is of generally rectangular cross section throughout its length, said passage being adapted to receive, endwise from the outer end of the shank, and to tightly fit, the end portion of a wooden hammer handle, the improvement characterized in that the interiorly exposed walls defining the passage have their end margins, at the outer end of the shank, curvilinear and convex toward the axis of the passage, curved about axes, respectively, which extend parallel to their associated wall portion and lie in a plane normal to the axis of the passage, and said margins curve outwardly continuously from the adjacent portions of their associated passage walls, respectively, from a location near the outer end of the shank in a direction toward the outer end of the shank, and said margins, at their inner limits being substantially tangent to their associated adjacent walls at their junctures therewith, a handle having one end portion tightly fitting the portion of the passage in the head and tightly fitting the portion of the passage in the shank from the inner end of the shank toward the outer end of the shank to the inner limits of said margins, and said handle having its side walls spaced inwardly, transversely of the passage, from said curvilinear margins.

References Cited in the file of this patent UNITED STATES PATENTS