US3786847A

US3786847A - Safety sledge-hammer

Info

Publication number: US3786847A
Application number: US00304048A
Authority: US
Inventors: E Schera
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-11-06
Filing date: 1972-11-06
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22

Abstract

This invention is a hammer adapted for the safe driving of long rods into the earth. Building codes require long rods drive into the ground for temporary and permanent ground connections for electric systems, or rods or pipe for marking surveyed locations. This hammer is provided with a cavity in one impact end in order to avoid outside misses dangerous to the person temporarily holding the rod. The cavity has conical walls for guiding the end of the rod or pipe which often vibrates out of exact alignment with the path of movement of the hammer head.

Description

nited States Patent 11 1 Schera, Jr. Jan. 22, 197 1 [5 1 SAFETY SLEDGE-HAMMER 3,019,827 2/1962 Jeffery et al. 145/36 Inventor: Enos L- g Jr-, 5 SW 37 FOREIGN PATENTS OR APPLICATIONS 714,794 9 1954 Great Britain 145/36 [22] Filed: Nov. 6, 1972 Primary Examiner-James L. Jones, Jr. [21] Appl' 304048 Assistant ExaminerJ. T. Zatarga Attorney, Agent, or Firm-Lloyd J. Andres [52] US. Cl 145/29 R, 145/36, 173/90 [51] Int. Cl. Bc 1/00 [58] Field 61 sear-611 145/29 R, 29 A, 29 B, 29 c, [57] ABSTRACT 145/29 D, 30.5, 36, 173/90; 254/26 This invention is a hammer adapted for the safe driving of long rods into the earth. Building codes require [56] References Cited long rods drive into the ground for temporary and per- UNITED STATES PATENTS manent ground connections for electric systems, or 538,382 4/1895 Petree .1 145/29 R rods of P f" mafking i i h 846 503 3/1907 Pamer 145,29 B hammer 1s prov1ded w1th a cavity In one Impact end In 1,122Z506 12/1914 Keating 145 29 A Order avoid utside misses dangerous t0 the Person 1,496,013 6/1924 Minick 145/29 A temporarily holding the The cavity has Conical 1,737,647 12/1929 Cummings 145/29 D walls for guiding the end of the rod or pipe which 2,086,694 7/1937 Beegle 145/29 A often vibrates out of exact alignment with the path of 2,833,323 5/1958 Strickland l/29 A movement of the hammer head, 2,917,349 12/1959 Saylor et al. /29 R 2,980,154 4/1961 Williamson 145/29 R 5 Claims, 5 Drawing Figures 1 SAFETY SLEDGE-HAMMER This invention relates in general to hammers and more particularly to a sledge-hammer with a predetermined cavity in the impact and thereof for driving relatively long flexible rods or pipe into the earth for a ground connection for electric circuits which are required by code authorities.

Prior sledge-hammers for driving rods into the earth required the user of the hammer to be suspended on a ladder and a second man for holding the rod in predetermined vertical alignment. Very often a miss" on the part of the user will inflict injury upon the person holding the rod, even when holding tools are used. This miss is often due to the vibratory nature of the relatively small diameter rod used for this purpose.

A principal object of the hammer is the provision of a cavity in one impact end of the hammer head. The opposite end of the hammer head is substantially flat for normal inverted use.

Since special rods and sometimes pipe are used for ground connection circuits there is also variance in the cross sectional diameters thereof, hence the cavity in the safety impact end has a flat bottom and divergent conical wall to provide a degree of self alignment when the end of the rod is struck.

These and other objects and advantages in one embodiment of the invention are described and shown in the following specification and drawing, in which:

FIG. 1 is a perspective view in reduced scale of a sledge-hammer incorporating a cavity in one impact end thereof.

FIG. 2 is an enlarged cross sectional view taken through section line 2-2, FIG. 1.

FIG. 3 is an end illustration of a rod being driven into the earth with the hammer shown in FIG. 1, with a portion of the hammer head broken away.

FIG. 4 is a perspective view in reduced scale of an alternate single hand hammer for use in driving smaller rods predetermined depths into a media.

FIG. 5 is a side elevation of a hammer head with a portion broken away showing a replaceable impact end.

Referring to FIG. 1, a sledge-hammer head 1, usually made from forged steel, has a special impact portion 2 on one end thereof, with a cavity 3 therein, to be hereinafter described. The opposite end surface 4 of the head 1 is planar and may be used for normal work. A two-hand handle 5 has one end portion 6 secured in a transverse hole through the head by a well known wedge means 7.

FIG. 2 illustrates the cavity 3 with the wall thereof having the shape of a frustrum of a cone terminating in a planar impact surface parallel the opposite surface 4.

FIG. 3 illustrates the manner in which a long rod 8, such as a copper clad ground rod having a length of approximately ten feet, is driven in the earth in the direction shown by arrow by the impact surface within the cavity 3. It is apparent that long rods, even when held by a persons hand or a tool, are subject to misalignment due to vibration or other causes where an impact surface would deflect from the rod with the risk of damage to the holder of the rod.

FIG. 4 illustrates a smaller single hand hammer of alternate construction, for driving smaller objects, with a cavity 3a applied to one end of the head in the same manner as applied to the head shown in FIG. 1.

FIG. 5 illustrates an alternate construction in a hammer having a head 1b with a normal planar driving surface 9 with the opposite end having a central threaded bore 10 for receiving a mated replacement head 11 having a threaded projection 12 for tightly mating the parallel transverse surfaces of the head lb and replacement head 11. The impact member is replaceable not only for cavities of different size to drive rods or pipes of different diameters, but also when the interior wall or the impact surface of the hammer is damaged.

It is to be understood that certain modifications in construction are intended to come within the teachings and scope of the above specification.

Having described my invention, 1 claim:

1. A sledge-hammer for driving relatively long linear objects comprising an elongated head of predetermined shape and weight,

said head symmetrical about a longitudinal central axis with the opposite end surfaces of said head normal said axis and including a hole through said head intersecting and normal said axis between said opposite surfaces including securing means for retaining an end portion of a substantially straight handle of predetermined dimensions for the simultaneous use of both right and left hands, cavity of predetermined dimensions and having conical convergent sloping side wall in one end of said end surfaces coaxial with and terminating at a predetermined depth forming a planar impact surface normal said axis.

2. The construction recited in claim 1 wherein said head is generally rectangular in cross section and having predetermined beveled longitudinal corners.

3. The construction recited in claim 1 wherein said head is generally cylindrical in shape with the edges of the said end surfaces having a chamfer of predetermined size and shape.

4. The construction recited in claim 1 including a predetermined chamfer in all angle junctions.

5. The construction recited in claim 1 wherein the size of said head and said handle are substantially proportionately reduced for providing for use by one hand.

Claims

1. A sledge-hammer for driving relatively long linear objects comprising an elongated head of predetermined shape and weight, said head symmetrical about a longitudinal central axis with the opposite end surfaces of said head normal said axis and including a hole through said head intersecting and normal said axis between said opposite surfaces including securing means for retaining an end portion of a substantially straight handle of predetermined dimensions for the simultaneous use of both right and left hands, a cavity of predetermined dimensions and having conical convergent sloping side wall in one end of said end surfaces coaxial with and terminating at a predetermined depth forming a planar impact surface normal said axis.