NASA Technical Reports Server (NTRS) 19970016165: Displaceable Gear Torque Controlled Driver

16 Pages·1.4 MB·English

by  NASA Technical Reports Server (NTRS)

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US005595251A
United States Patent [19] [ill Patent Number: 5,595,251
Cook, Jr. [45] Date of Patent: Jan. 21,1997
DISPLACEABLE GEAR TORQUE 4,533,337 811985 Schoeps .................................... 464125
CONTROLLED DRIVER 4,556,131 1211985 Chapman .................................... 19217
4,674,350 611987 Zaunberger et al. ................. 74/411 X
Inventor: Joseph S. Cook, Jr., Webster, Tex. 4,836,345 611989 Anderson ........................... 192156.1 X
4,909,105 311990 Namiki et al. ......................... 81157.36
Assignee: The United States of America as 4,989,478 U1991 Trivedi et al. ......................... 81157.36
5,092,410 911992 Wallace et al. ........................ 173193.5
represented by the Administrator of 5,094,330 311992 Lee ................................... 192156.61 X
the National Aeronautics and Space 5,125,298 611992 Smith ..................................... 81157.37
Administration, Washington, D.C.
Primary Examiner-Joseph J. Hail, III
Appl. No.: 288,114 Assistant Examiner-Jay A. Stelacone
Attorney, Agent, or Firm-James M. Cate
Filed: Aug. 10, 1994
t571 ABSTRACT
Int. C1.6 ............................. B25B 21/00; B23B 45/00
U.S. C1. ......................... 1731178; 173/216; 192/55.2; Methods and apparatus are provided for a torque driver
192L56.56; 192Li6.61; 74/411 including a displaceable gear to limit torque transfer to a
Field of Search ..................................... 173/216, 218, fastener at a precisely controlled torque limit. A biasing
1731217, 178, 176; 811467, 57.11, 57.14, assembly biases a first gear into engagement with a second
57.31; 74/411; 192/54.3, 55.2, 56.32, 56.56, gear for torque transfer between the first and second gear.
56.61, 69, 69.8, 69.9 The biasing assembly includes a pressurized cylinder con-
trolled at a constant pressure that corresponds to a torque
References Cited limit. A calibrated gage and valve is used to set the desired
torque limit. One or more coiled output linkages connect the
U.S. PATENT DOCUMENTS first gear with the fastener adaptor which may be a socket for
2,069,882 211937 Hall ............................................. 81157 a nut. A gear profile provides a force that
2,781,682 211957 Hemdon ................................... 81152.4 overcomes the bias to limit torque at the desiredtorque limit.
3,608,334 9/1971 Zinner ................................ 192156.3 x Multiple fasteners may be rotated simultaneously to a
3,799,307 311974 Tate ...................................... 192L56.32 desired torque limit if additional output spur gears are
3,845,673 1111974 Karden et al. ............................ 74/751 provided. n eto rque limit is adjustable and may be different
3,905,254 911975 Palatnick et al. ........................ 81157.3 for fasteners within the same fastener configuration.
3,960,035 611976 Workman, Jr. et al. ............ 1731178 X
3,983,764 1011976 Hicks ..................................... 741411 X
4,513,827 411985 Dubiel ..................................... 1731178 18 Claims, 7 Drawing Sheets
54 78
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U.S. Patent 5,595,251
Jan. 21,1997 Sheet 1 of 7
108
71A
70A
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61A
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110
FIG. 1 FIG. 4 A
1 OA
100
0 '
FIG. 4
U.S. Patent 5,595,251
Jan. 21, 1997 Sheet 2 of 7
54
78
1
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FIG. 3
U.S. Patent 5,595,251
Jan. 21,1997 Sheet 3 of 7
350
360
352
353
353
364
360
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358 356 358
FIG. IO
130
132 136 140
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FIG. 5 144 > 1 + 1
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U.S. Patent 5,595,251
Jan. 21, 1997 Sheet 4 of 7
160
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FIG. 6
U.S. Patent 5,595,251
Jan. 21,1997 Sheet 5 of 7
FIG. 7k
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206
208
200
FIG. 6 A
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FIG. 6B
165 I64
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FIG. 7 FIG. 6C
U.S. Patent 5,595,251
Jan. 21, 1997 Sheet 6 of 7
U.S. Patent 5,595,251
Jan. 21,1997 Sheet 7 of 7
266 0
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5,595,25 1
1 2
DISPLACEABLE GEAR TORQUE under reactive forces produced when the nuts engage the
CONTROLLED DRIVER wheel attachment bolts.
U.S. Pat. No. 5,092,410 to Wallace et al. discloses a
ORIGIN OF THE INVENTION hydraulic torque impulse generator using a dual piston
5 arrangement to provide impacts to a rotatable anvil. Auto-
The invention described herein was made by an employee matic shut-off and control apparatus is provided for limiting ~
of the United States Government and may be manufactured the pressure without reversing the direction of the driving
and used by or for the Government of the United States of clutch cage. A pressure venting arrangement permits one
America for governmental purposes without the payment of impact per revolution.
any royalties thereon or therefor. lo U.S. Pat. No. 4,533,337 to K. C. Schoeps discloses a
hydraulic torque impulse tool having a power inertia drive
TECHNICAL FLELD member, a hydraulic fluid chamber, and a cam driven piston
in the fluid chamber for reciprocating movement.
The present invention generally relates to torque control
U.S. Pat. No. 5,125,298 to C. 0. Smith discloses an
mechanisms and methods in threaded fastener drivers, such 15
automatic wheel assembly line in which an array of fastener
as nut runners and some types of screw drivers. More
members is prepared, corresponding in number and geomet-
specifically, the present invention relates to a driver having
ric pattern to the array of co-acting fastener members on the
a torque driver configuration for precisely limiting torque
vehicle hub and to the array of bolt holes on the wheel
applied to the threaded fastener.
2o assembly. The assembly includes a source of fasteners, a
feeder mechanism having an outboard face, means defining
BACKGROUND ART a plurality of fastener receptacles, means operative to trans-
port fasteners and means to move the loaded fasteners.
It is often desirable to apply a highly accurate and
U.S. Pat. No. 4,989,478 to Trivedi et al. discloses an
repeatable torque to one or more fasteners, such as nuts,
screws, or the like. Prior art methods, both manual and 25 apparatus for tightening or loosening a plurality of bolts or
other rotatable elements in which a drive socket and a pair
automatic, do not provide an uncomplicated mechanism that
of reaction sockets are supported by an elongated beam
limits torque applied to a fastener with sufficient accuracy
member.
that the fastener is repeatably tightened with a torquing force
having a tight, consistent tolerance range. This is particu- U.S. Pat. No. 3,905,254 to Palatnick et al. discloses a tool
larly true for drivers used to simultaneously install multiple 30 for loosening and removing the lug nuts of an automobile .
fasteners. The torque applied to each fastener by a torque and truck wheels with selectively positioned non-rotating
driver ideally is adjustable, although the torque applied to stabilized sockets.
one or more fasteners in a particular fastener configuration As can be understood from a review of the background as
may be required to be different than the torque applied to discussed above, there remains the need for an improved
other fasteners in the same configuration. Numerous prior 35 torque control mechanism that offers variable control over
art drivers have attempted to solve these problems. torque applied to one or more fasteners, a simplified con-
U.S. Pat. No. 3,845,673 to Karden et al. discloses a struction for higher reliability, flexibility as to configuration
two-speed nut runner that has a low torque clutch designed of the fasteners, and a driver which may be produced at
for disengagement at a predetermined, relatively low torque. reduced levels of capital investment. Those skilled in the art
A second high torque clutch automatically takes over the 40 will appreciate that the present invention provides solutions
transmission of torque at a lower speed and higher torque to these and other problems.
while holding the low torque clutch in a fully released
position by means of a piston that is placed inside the output
shaft of the nut runner. STATEhENT OF THE INVENTION
45
U.S. Pat. No. 2,069,882 to W. Hall discloses a wrench for
The present invention provides a method and apparatus
tightening a plurality of securing members that includes a
for an improved torque controlled driver for applying torque
plurality of rotatable spindles operable to transmit tightening
to a fastener. The torque driver includes a driver housing,
forces to the securing members, and a transmission operable
and a first gear carried by the driver housing for relative
by a single drive to rotate the several spindles independently
50 rotation with respect thereto. The first gear has first gear
to tighten the members to the same degree of tightness. The
teeth mounted around a circumferential portion thereof. A
transmission includes pinions associated with the spindles,
second gear is provided to be displaceable with respect to the
and an element. rotated bv the drive. ouerable to succes-
, I first gear between an engaged and a disengaged position.
sively ''Operate with Pairs Of Opposite pinions The second gear also has second gear teeth mounted around
to partially rotate the same.
55 a circumferential portion thereof. The second gear teeth and
pat. NO. 2,781,682 to w. B. Hemdon discloses a the fist gear teeth mesh in the engaged position, and at least
torque Wrench With multiple spindles that Provides a steady one of the first and second gear teeth define an angled tooth
torque for setting ~~ew-threadfeadst enings while allowing profile to produce a separating force in response to torque
the drive to slip when the fastening is tight. transfer between the first and second gears for moving the
U.S. Pat. No. 4,909,105 to Namiki et al. discloses an 60 second gear to the disengaged posicon to thereby 'iimit
automated nut driving apparatus having a plurality of motors torque transferred between the first and second gears and to
for rotating respective ones of a plurality of drive shafts to the fastener. A pressurized-chamber assembly is provided to
respective sockets holding nuts. The nut driver includes a bias the second gear toward the engaged position. The
plurality of universal joints connecting the sockets and drive pressurized-chamber assembly includes a chamber for pres-
shafts while allowing the sockets to be tilted with respect to 65 surization and a constant pressure fluid supply to maintain a
the drive shafts. Universal joints are movable axially with constant pressure within the chamber to thereby produce a
respect to the drive shafts to allow the sockets to be retracted substantially constant bias on the second gear as the second
5,595,251
3 4
gear is displaced from the engaged to the disengaged posi- FIG. 6B is a sectional view of the driver of FIG. 6 along
tion. the lines 6B-6B;
In operation torque is transferred from the first gear to the FIG. 6C is a sectional view of the driver of FIG. 6 along
second gear and to the fastener. The angled tooth on at least the lines 6C-6C;
one of the first and second gears produces a separating force 5 FIG. 7 is an elevational view, in section, of the driver of
between the first and second gears during the transfer of FIG. 6 with gears displaced;
torque between the first and second gears. The second gear
FIG. 7A is an elevational view, in section, of the axial
is biased toward the first gear with a constant bias that
force clutch of FIG. 6 in the disengaged position;
remains substantially constant as the second gear moves
FIG. 8 is an elevational view, in section, of a bevel gear
away from the first gear in response to the separating force 10
driver with pneumatic bias;
and the first gear is rotated to apply torque to the second gear
and to the fastener until the separating force overcomes the FIG. 8A is an elevational view, in section, of a bevel gear
constant bias and separates the first and second gears to limit driver without an intermediate bevel gear assembly;
torque transfer between the first and second gears. FIG. 9 is an elevational view, in section, of a spur gear
An object of the present invention is to provide an 15 driver with adjustable fastener driver configuration;
improved torque driver. FIG. 9A is a sectional view of the driver of FIG. 9 along
Another object is to provide a torque driver for selectively along line 9A-9A; and
controlling torque to provide either a constant or varying FIG. 10 is a top view, in section, of a driver for a
torque to each of a plurality of fasteners. non-circular fastener configuration.
20
Another object of the present invention is to provide a While the present application includes claims directed to
torque driver that will tighten one or more fasteners to a a driver having a pneumatic biasing system as explained
more precise torque. herein, it will be understood that figures which show spring
Yet another object of the present is to provide a torque biasing may be modified for pneumatic biasing and are
driver that is adaptable to a variety of fastener configura- 25 necessary to provide a complete understanding of the
tions. present invention. It will also be understood that claims
directed to a pneumatically biased driver will also include
A feature of the present invention is a pressurized cylinder
drivers that may, in addition to pneumatic biasing, include a
assembly.
spring or other biasing means.
Another feature of the present invention includes a con-
stant pressure pneumatic supply system. 30 Thus, while the invention will be described in connection
with the presently preferred embodiments, it will be under-
Yet another feature of the present invention is a calibrated
stood that it is not intended to limit the invention to these
gage used to select a torque limit.
embodiments. On the contrary, it is intended to cover all
An advantage of the present invention is an uncompli- alternatives, modifications, and equivalents as may be
cated, economical construction. 35 included in the spirit of the invention.
Another advantage of the present invention is a construc-
tion that allows the driver to be adapted to a wide variety of DESCRIPTION OF THE PREFERRED
fastener configurations. EMBODIMENTS
Another advantage is the ability to provide different The present invention relates to an improved torque driver
torque to different fasteners within the same fastener con- 40 mechanism operable to transmit a precisely controllable
figuration. degree of torque to a driven member such as a nut, screw, or
Other objects, features and intended advantages of the the like. The torque driver may receive an input torque
present invention will be readily apparent by the references which is greater than a desired output torque and is operable
to the following detailed description in connection with the to limit the input torque to the desired output torque level.
accompanying drawings and claims. 45 In very general terms, the application of gears for torque
transmission between shafts falls into three categories of (1)
parallel shafts, (2) shafts with intersecting axes, and (3)
BFSEF DESCRIPTION OF THE DRAWINGS
shafts neither parallel nor intersecting but skew.
FIG. 1 is a schematic representation showing reaction While the present application includes claims directed to
50
forces and principal features with a pinion (driver) and a driver having a pneumatic biasing system as explained
driven gear; herein, it will be understood that figures which show spring
FIG. 2 is an elevational view, in section, of a torque driver biasing may be modified for pneumatic biasing and are
with gears in engaged position; necessary to provide a complete understanding of the
FIG. 3 is an elevational view, in section, of the driver of 55 present invention. It will also be understood that claims
FIG. 2 with gears displaced from each other; directed to a pneumatically biased driver will also include
drivers that may, in addition to pneumatic biasing, include a
FIG. 4 is a top view, in section, of a driver according to
spring or other biasing means.
FIG. 2 but with a pressurized cylinder biasing assembly;
The basic gear forces involved in operation of a torque
FIG. 4A is a side view, in section, of the driver of FIG.
along the line 4A4A; 60 driver in accord with the present invention are best described
in connection with FIG. 1 wherein gear teeth 12 and 14, on
FIG. 5 is a schematic representation of a self-venting
respective gears 13 and 15, are shown in some detail.
pressure bias control system;
Respective gear teeth 12 and 14 provide a positive drive,
FIG. 6 is an elevational view, in section, of a bevel gear maintaining exact velocity ratios between pinion or driver
driver; 65 gear 13 and driven gear 15 to positively rotate one fastener,
FIG. 6A is a sectional view of the driver of FIG. 6 along or more than one fasteners simultaneously, up to the desired
the lines 6A-6A; torque.