Bi-directional, multiple range torque measuring device

A torque measuring device designed for convenient use intermediate a ratchet wrench and socket is provided with a pair of oppositely disposed compression springs that are so housed within the first of a pair of complementary plates as to yield to a rotational force applied in either direction, the compressible yield of one of the springs as the ratchet wrench is turned in a given direction producing a lag in the rotation of the second of the plates which is measured in terms of torque by means of a pointer and a calibrated scale, the convenient substitution of the springs with selected springs of varying tension permitting the wide range of torque measurement including measurement in foot pounds, inch pounds, and metric.

BACKGROUND OF THE INVENTION 
Well known torque sensing tools and devices have provided a wide variety of 
means for either measuring torque or for permitting slippage of a 
supporting tool when a predetermined torque is exceeded. Included among 
such means, and most commonly found in the torque measuring art, has been 
the use of elongated torsion bars or rods for operatively connecting a 
wrench or the like and a socket or similar workpiece. Since torsion bars 
for this purpose have been selected according to their particular modulus 
of elasticity, torque measurement has generally been achieved by variously 
coupling a pointer or indicator to one extremity of a torsion bar and a 
calibrated scale to the other extremity thereof, the pointer being 
displaced from its normal "zero" reading as the torsion bar flexes or 
twists. Typical of the torque measuring art involving the use of torsion 
bars or rods are U.S. Pat. Nos. 3,911,736 to Miller, 3,691,826 to 
Grabovac, 3,481,193 to Schubert and 2,934,946 to Engquist. Although 
generally suitable for torque measuring per se, these torsion bar devices 
have generally been of an intricate nature entailing relatively high 
manufacturing costs, and have further been limited in use to those 
applications where space limitations have not been critical, as where a 
ratchet wrench or the like may be operated at a sufficient distance from 
the socket to accommodate the elongated bar. 
Also found in the torque measuring art are various devices making use of 
torsion or helical springs, such as U.S. Pat. Nos. 2,151,953 to Zimmerman 
and 2,250,736 to Torresen; and making use of tension springs such as U.S. 
Pat. No. 1,574,491 to Leake. These torsion springs and tension springs 
have been characterized by some means of end-anchoring, thereby permitting 
torque measurement in one direction only. 
An additional common characteristic of known torsion bar and spring, and 
tension spring torque measuring devices is that they are designed for 
measurement in predetermined set torque ranges only, and lack the 
flexibility of being readily adaptable to accommodate widely differing 
ranges of torque. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the present invention to provide an 
effective and reliable torque measuring device that is simple in design 
and economical to manufacture. 
It is another object of the present invention to provide a torque measuring 
device that is compact in size, that may be used in work areas where space 
is limited, and wherein the ratchet wrench or the like may be operated in 
close proximity to the socket or workpiece. 
It is still another object of the present invention to provide a torque 
measuring device that may be used for measuring torque applied in either 
direction, and that may be readily and conveniently adapted for measuring 
widely differing torque ranges. 
An important aspect of the present invention is the provision of a pair of 
relatively flat complementary circular disks or plates that may be 
inserted between a ratchet wrench or the like and a socket or the like, a 
first of the complementary plates housing a pair of arcuately disposed, 
equally tensioned, loose-ended compression springs that are separated at 
adjacent ends by a dowel pin forming part of the first plate, and 
separated at their opposite adjacent ends by a dowel pin forming part of 
the second of the plates, rotation of the first of the plates in either 
direction, by means of the ratchet wrench to which it is coupled, serving 
to activate and to compress the downstream compression spring as the 
second of the plates is rotated at a slower rate in the same direction, 
the resulting lag between the rotation of the two plates being measured by 
a pointer fixed to the second plate and a calibrated scale fixed to the 
upper surface of the first of the plates. 
Another important aspect of the present invention is the provision of 
simple and convenient means by reason of which a pair of complementary 
plates may be readily assembled for relative rotation, and readily 
separated for the convenient substitution of pairs of compression springs 
of widely differing tension, whereby measurement in widely differing 
torque ranges may conveniently be accomplished.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The invention resides in the provision of a torque measuring device that is 
economical to manufacture and effective for use in confined areas and for 
measuring multiple ranges of torque applied in either direction. The 
torque measuring device is comprised of a first or upper plate and a 
second or lower plate which are rotatable relative to one another, the 
first plate being readily couplable to a ratchet wrench or the like and 
the second plate being readily couplable to a socket or the like, the 
first plate effectively housing a pair of arcuately disposed loose-ended 
compression springs which are separated by and cooperable with a pair of 
dowel pins, one of the dowel pins being fixed to the first plate and the 
other to the second plate. The arrangement of the pair of compression 
springs in an accommodating groove in the lower surface of the first plate 
is such that rotation of the ratchet wrench in a given direction will 
result in the compression of the downstream spring and the delayed 
rotation of the second plate and socket in the same direction. 
With reference to FIG. 1, the inventive torque measuring device generally 
designated at 11 is comprised of a first or upper circular plate 13 and a 
second or lower circular plate 15. These pair of circulate plates are 
coupled together for independent rotation by means of a hereinafter 
described shoulder screw 17. The first plate 13 is provided with a 
centrally formed square recess 19 to accommodate the projecting square 21 
of a ratchet wrench 23. Also formed in the first plate 13, in coaxial and 
communicating relationship with the square recess 19 is a first 
cylindrical recess 25 to accommodate the shoulder screw 17, the 
particulars of the square recess 19 and first cylindrical recess 25 being 
described in greater detail hereinafter. The second or lower plate 15 is 
provided with a centrally formed depending square 27 to accommodate the 
square recess of a socket 29. The second or lower plate 15 is also 
provided with an indicator or pointer 31 which is secured to the 
peripheral surface of the lower plate 15 by means of a screw 33. 
As best shown in FIG. 2, the upper surface of the first plate 13 is 
provided with a calibrated scale 35 including a central zero marking and 
identical indicia extending in either direction therefrom, such indicia 
permitting readable designations of torque applied by the ratchet wrench 
23 in either direction. As will be evident infra in connection with the 
selection of compression springs of differing tension, the calibrated 
scale 35 may be contained on a replacement plate such that torque readings 
in widely differing ranges may be provided, such as in terms of inch 
pounds, foot pounds, or metric. As best illustrated in FIGS. 2 and 3, the 
first or upper plate 13 is provided with a continuous circular groove or 
channel 37 formed in the lower surface thereof, such channel or groove 
serving to house a pair of loose-ended, equally tensioned compression 
springs 39. The first plate 13 is also provided with a first dowel pin 41 
fixed to the upper plate 13 and projecting into the groove or channel 37 
to provide separation between the upstream loose ends of the pair of 
compression springs 39. It is to be noted that the first dowel pin 41 is 
to be so dimensioned as to clear the upper surface of the second plate 15 
as the first plate 13 is rotated in either direction. 
As best illustrated in FIGS. 1 and 4, the second plate 15 is provided with 
a second dowel pin 43 which is fixed to the upper surface of the plate 15 
and extends upwardly into the continuous circular groove 37. It is to be 
noted that the second dowel pin 43 is to be so dimensioned as to clear 
both the side walls and upper surface of the groove 37, when the second 
plate 15 is operably coupled to the first plate 13. The mounting of the 
previously mentioned indicator or pointer 31, as best shown in FIG. 4, is 
accomplished by means of a threaded hole 45 into which the previously 
mentioned screw 33 is secured. As also best shown in FIGS. 1 and 4, the 
second plate 15 is provided with a centrally formed second cylindrical 
recess 47 which also serves to accommodate the shoulder shank of the screw 
17. The depending square 27 of the second plate 15 is provided with a 
centrally formed threaded third cylindrical recess 49 into which the 
threaded end of the shoulder screw 17 is secured, such third cylindrical 
recess being disposed in communicating relationship with the second 
cylindrical recess 47. 
The mounting of the first and second plates 13 and 15, for independent 
rotation, is accomplished by the linear dimensioning of the shoulder screw 
17, and by a first and second step ledge 51 and 53 best shown in FIG. 1. 
The first step ledge 51 is formed at the intersection of the square recess 
19 and first cylindrical recess 25 formed in the first plate 13, and the 
second step ledge 53 is formed at the intersection of the second 
cylindrical recess 47 and threaded third cylindrical recess 49 formed in 
the second plate 15. The dimensioning of the shoulder shank of the screw 
17 is such that with the lower limit of the shoulder abutted securely 
against the second step ledge 53, the head of the shoulder screw 17 is 
provided with a slight clearance relative to the first step ledge 51. 
The above described mounting of the plates 13 and 15 lends itself to 
convenient disassembly of the plates, a process requiring the removal of 
the shoulder screw 17, as by means of a screwdriver inserted into the 
square recess 19. Upon such convenient disassembly of the plates 13 and 
15, pairs of compression springs 39 of differing tension may be inserted 
conveniently to provide torque measurement in differing ranges, as 
indicated supra. 
Although the inventive torque measuring device has been described in 
considerable detail, it will be appreciated that various changes therein 
may be made by those skilled in the art without departing from the true 
spirit and scope of the invention.