Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-02-05
2001-05-08
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S090100
Reexamination Certificate
active
06227076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a wrench particularly adapted for torquing round shafts or nuts or the like structures, and especially those structures such as the inner tie rod threaded or pressed on nuts of automobiles, which nuts on structures which are in confined locations and may not be easily accessible laterally, or nuts on structures which are connected at both ends to other structure and thereby not readily accessible for power rotating.
2. Prior Art
Heretofore, specialty type wrenches have been developed for torquing nuts, pipes and other variously shaped structures as shown in U.S. Pat. Nos. 2,700,315; 5,282,830; 3,783,703; 5,553,520; 3,906,822; 2,989,880; 4,676,125; 3,664,213; 3,527,327; 2,992,735; 4,724,730; 2,659,257 and Ger. 3,106,510.
While these wrenches may be adequate to torque the items for which they were designed, they cannot meet the non-slip requirements for torquing such items as automotive rack and pinion inner tie rod assemblies which requires considerable torque in a confined space, and which invites severe knuckle or other injury when the torquing tool or wrench slips.
OBJECTS OF THE INVENTION
Objects, therefore, of the present invention are: to provide a heavy-duty, non-slip torque wrench, i.e., a drive head with or without handle means, which head has automatic adjustability to accommodate a range of work item diameters, such as from about 1.4 to about 1.6 inches, wherein the wrench is comprised of highly accurately machined or cast steel, preferably stainless steel components and is exceptionally safe to use; and to provide such a wrench with structure which is adaptable for mounting onto rotative power equipment such as lathes, drill presses or milling machines for being torque rotated thereby for loosening or tightening exceptionally difficult threaded on or pressed on workpieces.
SUMMARY OF THE INVENTION
The above and further objects hereinafter becoming evident have been attained in accordance with the present invention thru the discovery of wrench structure which is defined in its broad sense as a drive head having a generally disc-shaped body and an access cap forming a cavity means, each of said body and cap being formed with a workpiece receiving bore and, in one special embodiment, is provided with a lateral slot for allowing a workpiece shaft portion or nut or the like to slide laterally into the bore, and further having a plurality of jaw members pivotally mounted in the cavity means in a substantially circular pattern around said bore wherein the jaw members are positioned preferably but not essentially in a symmetrical manner around said bore, each jaw member having a gripping face extending at least partially into the bore, wherein each jaw member has a pivot segment as measured along its longitudinal axis to its intersection with the lateral midpoint of said gripping face, wherein each said face is formed substantially on a radius line which makes an angle of from about 9.0° to about 20°, most preferably from about 11.5° to about 14.5° with said longitudinal axis at said midpoint, thereby to provide each said face with a variable length neutral contact portion and a variable length working contact portion.
In certain preferred embodiments:
(a) the jaw members are formed with integral stub shafts which are pivotally mounted in bearing sockets in the body and access cap;
(b) spring means are provided on the head to bias the jaw members toward their gripping positions;
(c) first shoulder means is provided on a radially outer portion of each said jaw member, and a hand operable, generally sleeve-shaped actuator means is rotatably mounted on said body radially outwardly of said cavity means and is provided with second shoulder means engageable with said first shoulder means upon rotation of said actuator means to thereby selectively pivot said jaw members toward or away from engagement with a workpiece positioned in said bore; and
(d) wherein the ratio of the length of said radius line to the length of said pivot segment, as measured in the same units, preferably ranges from about 2 to about 7, and most preferably from about 2.5 to about 3.5.
REFERENCES:
patent: 3906822 (1975-09-01), Hertelendy et al.
patent: 4644830 (1987-02-01), Bailey et al.
patent: 5282830 (1994-02-01), Reynolds
Smith James G.
Thomas David B.
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