US 2757694 A
Description (OCR text may contain errors)
7, 1 c. M. CURTIS SHOCK RESISTI'NG HAMMER Fiied Jan. 28, 1954 IN V EN TOR.
United States Patent 2,757,694 SHOCK RESISTING HAMMER Cecil M. Curtis, Pant City, n1. Application January 28, 1954, Serial No. 406,852 I 3 Claims. (Cl. 145-29 This invention relates to hand tools and particularly to hammers. Inthe preferred form of the invention illustrated, the principles of the invention are applied to a claw hammer having a head portion of somewhat conventional design.
It is a primary object of the invention to provide what may be termed a shock resisting hammer, wherein the physical shock resulting from the impact of the hammer head striking against a nail or other object is resisted or absorbed in the hammer handle, and is thus not transmitted to the hand of the user. Obviously, this results in a hand tool which is efficient in acomplishing its purpose, yet does not cause perceptible discomfort, nor unduly tire the user.
A still further object of the invention resides in the provision of a hammer having the characteristics indicated above, yet also possessing the desirable characteristics of proper weight and balance, so that it is capable of delivering a blow of maximum energy at the point of impact, yet has that intangible quality of proper feel demanded by skilled workmen.
A preferred embodiment of the invention is illustrated in the drawings attached hereto, wherein:
Figure 1 is a central sectional view of a hammer as coni templated by this invention; and
Figures 2, 3, 4 and are detail sectional views taken on the lines 22, 33, 4-4 and 5-5, respectively.
The hammer disclosed herein is characterized by a unique handle construction, whereby the objects of the invention are accomplished. The handle, generally indicated at 10, is shown as attached to a head 11 which may be of conventional form. Briefly, the handle consists of a tubular hand grip portion 12, a double tubular shank 13, and a neck 14 which is also of double tubular construction, but further reinforced by a solid central core or plug.
The details of construction may best be described in connection with a description of the manner of making and assembling the device. In the manufacture of the hammer, a length of round steel tubing 16 approximately the full length of the finished hammer handle is first partially flattened at 17, in a zone corresponding to the hand grip section 12. The tube is deformed only to the extent of making it oval in cross section, however, as indicated in Figures 4 and 5. The lower end of the tube is then covered by a sleeve, or hand grip. This is assembled by pressing a plurality of nonmetallic, resilient washers 18 upwardly upon the tube 16, in stacked relationship. The uppermost end of the stack of Washers may be allowed to move upwardly beyond the central portion 19 of the handle, so that the lower end of the stacked washers may he slid upwardly somewhat beyond the lowermost end of the tube. An end plate 20 is then applied to the lower end 21 of the tube. Preferably, it is secured by means of a central stud 22 which extends upwardly into the tube. The tube walls are then indented at 23 to permanently secure the parts together.
After the end plate 20 has been thus aifixed, a metal 2,757,694 Patented Aug. 7, 1956 collar 24 is slid downwardly over the neck 14 and shank 13 of the inner tube to hold the washers in position, and the stacked washers 18 are thus moved downwardly and somewhat compressed. In the preferred form of the invention, these washers are of cork composition, so that they have considerable compressibility and hold themselves against each other sufliciently tightly to form a substantially solid hand grip.
The collar 24 is held down againstthe cork washers by an outer reinforcing tube 25. This outer tube is of proper size to fit closelyaround the tube 16. Its lower end is seated .in a counterbore 26 in the collar 24. The head portion 11 of the hammer is then applied to the upper end of the tube 16, and the upper extremity of the tube 25 is received in a counterbore 27 in the hammer head. The counterbores 26 and 27 are press fitted on the tube 25 in assembly.
The entire assembly is -then locked together by the insertion of a cylindrical, taper headed metallic plug 28 in the upper end of the tube 16. This plug is slightly enlarged and tapered at its uppermost end, so as to spread the upper end of the inside tube 16 and permanently lock the tube within the correspondingly shaped bore of the head. The upper end of this bore is then welded at 29 to form an integral closure with the plug and tube and to fill any recess in the upper surface of the hammer head. If desired, the upper surface may thereafter be ground smooth and flush. After assembly, the lower shank portion 13 is flattened to oval cross section indicated in Figure 3, but in the preferred form of the invention, the plug 28 is of such length as to extend downwardly beyond the hammer head and to provide a solid neck 14 between the shank portion 13 and the head 11.
A hammer constructed in the manner indicated above will be found to have excellent characteristics of feel and balance, and it may be demonstrated that such a construction is capable of delivering a blow of maximum impact energy without perceptible sting or shock.
The two oval tubular shank sections, one within the other, afford adequate strength at this point of strain, yet the exterior sleeve acts as a mute to impact vibration. The vibration of impact is further reduced by the presence of the closely fitted central plug 28 which extends into the neck of the tubular handle.
Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent 1s:
1. A hand tool comprising an impact head having an eye in the form of a cylindrical bore with parallel side walls extending to a substantial depth in said head, in combination with a long hollow tubular metallic handle; said handle having an oval hand grip portion at the end remote from the head of the tool, with a resilient non metallic sleeve surrounding said hand grip portion in telescoping relationship therewith; a cylindrical end portion of said tubular handle having a diameter corresponding to the diameter of the aforementioned cylindrical bore in the head and press fitted within said bore; said tubular handle being partially flattened in a shank zone of oval cross section between the hand grip and the head blending into a neck portion of circular cross section adjacent the point of connection with the head.
2. A hand tool comprising an impact head having an eye in the form of a cylindrical bore with parallel side walls extending to a substantial depth in said head and a relatively shallow counterbore; in combination with a long hollow tubular metallic handle; said handle having an oval hand grip portion at the end remote from the head of the tool, with a resilient nonmetallic sleeve surrounding said hand grip portion in telescoping relationship therewith; a cylindrical end portion of said tubular handle having a diameter corresponding to the diameter of the aforementioned cylindrical bore in the head and press fitted within said boreysaid tubular handle being'partially flattened in a shank zone of oval cross section between the hand grip and the head blending into a neck portion of circular cross section adjacent the'point of connection with the head; an exterior metallic tube of cross sectional shape corresponding to the shank portion of the handle and telescoped thereover, with one end of said exterior tube seated in the aforementioned counterbore of the extending to a substantialdepth in saidhead; a long, hollow, tubular handle having a hand grip portion at theend remote from the head of the tool with a resilient nonmetallic sleeve surrounding said hand grip portion in telescoping relationship therewith; -said hand grip portion being of oval configuration, with a portion of the handle of oval form tapering toward and blending into a cylindrical end portion corresponding to the diameter of the aforementioned cylindrical bore in the head and press fitted within said bore; with a generally cylindrical-metallic plug corresponding to the internal diameter of said cylindrical end portion of the handle wedged therein to lock the cylindrical portion of the handle within the aforementioned bore; said plug, said tube and said impact head being secured to each other to retain the parts in assembled relation and to provide an integral closure for the end of the aforementioned bore.
References Cited in the file of this patent UNITED STATES PATENTS 419,953 Huller Jan. 21, 1890 894,155 Layton July 21, 1908 895,903 Smith Aug. 11, 1908 1,089,043 Burgess Mar. 3, 1914 1,158,032 Eastman Oct. 26, 1915 2,603,260 Floren July 15, 1952 FOREIGN PATENTS 290,678 Switzerland Aug. 17,1953