Displaceable spur gear torque controlled driver amd method

Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

TECHNICAL FIELD 
The present invention generally relates to torque controlled drivers for 
threaded fasteners. More specifically, the present invention relates to a 
torque driver configuration for selectively limiting and controlling 
torque applied to one or more fasteners. 
BACKGROUND ART 
It is often desirable to apply a selectively limited or controlled torque 
to one or more fasteners, such as nuts, screws, or the like. Over-torquing 
can cause fastener failure and component damage. Such fasteners may be 
used, for instance, to secure a tire to a wheel, or to secure a manifold 
assembly to an engine. In some cases, it is necessary that a configuration 
of fasteners be tightened relatively simultaneously, with each fastener 
tightened with the same torque limits and at the same time. It may also be 
desirable to tighten various configurations of fasteners without the need 
to change the driver. In some cases, the fasteners may be oriented 
circularly, and in other cases the fasteners may have a rectangular, star, 
or other configuration. The torque applied to each fastener ideally is 
adjustable, although the torque applied to one or more fasteners in a 
particular configuration may need to be different than the torque applied 
to other fasteners within the same configuration. It is also desirable for 
some purposes to be able to remove multiple fasteners simultaneously. 
Numerous prior art drivers have attempted to solve these problems. 
U.S. Pat. No. 3,845,673 to Karden et al. discloses a two-speed nut runner 
that has a low torque clutch designed for disengagement at a 
predetermined, relatively low torque. A second high torque clutch 
automatically takes over the transmission of torque at a lower speed and 
higher torque 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. 
U.S. Pat. No. 2,069,882 to W. Hall discloses a wrench for tightening a 
plurality of securing members that includes a plurality of rotatable 
spindles operable to transmit tightening forces to the securing members, 
and a transmission operable by a single drive to rotate the several 
spindles independently to tighten the members to the same degree of 
tightness. The transmission includes pinions associated with the spindles, 
and an element, rotated by the drive, operable to successively cooperate 
with pairs of substantially opposite pinions to partially rotate the same. 
U.S. Pat. No. 2,781,682 to W. B. Herndon discloses a torque wrench with 
multiple spindles that provides a steady torque for setting screw-threaded 
fastenings while allowing the drive to slip when the fastening is tight. 
U.S. Pat. No. 4,909,105 to Namiki et al. discloses an automated nut driving 
apparatus having a plurality of motors for rotating respective ones of a 
plurality of drive shafts to respective sockets holding nuts. The nut 
driver includes a plurality of universal joints connecting the sockets and 
drive shafts while allowing the sockets to be tilted with respect to the 
drive shafts. Universal joints are movable axially with respect to the 
drive shafts to allow the sockets to be retracted under reactive forces 
produced when the nuts engage the wheel attachment bolts. 
U.S. Pat. No. 5,092,410 to Wallace et al. discloses a hydraulic torque 
impulse generator using a dual piston arrangement to provide impacts to a 
rotatable anvil. Automatic shut-off and control apparatus is provided for 
limiting the pressure without reversing the direction of the driving 
clutch cage. A pressure venting arrangement permits one impact per 
revolution. 
U.S. Pat. No. 4,533,337 to K. C. Schoeps discloses a hydraulic torque 
impulse tool having a power inertia drive member, a hydraulic fluid 
chamber, and a cam driven piston in the fluid chamber for reciprocating 
movement. 
U.S. Pat. No. 5,125,298 to C. O. Smith discloses an automatic wheel 
assembly line in which an array of fastener members is prepared, 
corresponding in number and geometric pattern to the array of co-acting 
fastener members on the vehicle hub and to the array of bolt holes on the 
wheel assembly. The assembly includes a source of fasteners, a feeder 
mechanism having an outboard face, means defining a plurality of fastener 
receptacles, means operative to transport fasteners and means to move the 
loaded fasteners. 
U.S. Pat. No. 4,989,478 to Trivedi et al. discloses an apparatus for 
tightening or loosening a plurality of bolts or other rotatable elements 
in which a drive socket and a pair of reaction sockets are supported by an 
elongated beam member. 
U.S. Pat. No. 3,905,254 to Palatnick et al. discloses a tool for loosening 
and removing the lug nuts of an automobile and truck wheels with 
selectively positioned non-rotating stabilized sockets. 
As can be understood from a review of the background as discussed above, 
there remains the need for an improved driver that offers variable control 
over torque applied to one or more fasteners, a simplified construction 
for higher reliability, flexibility as to configuration of the fasteners, 
and a driver which may be produced at reduced levels of capital 
investment. Those skilled in the art will appreciate that the present 
invention provides solutions to these and other problems. 
STATEMENT OF THE INVENTION 
The present invention provides an improved method and apparatus for a 
torque controlled driver for applying torque to a fastener and having a 
driver housing with a first shaft carried by the driver housing having a 
first shaft axis extending longitudinally therethrough. The first shaft 
carries a first gear for rotation about the first shaft axis. The first 
gear has first gear teeth mounted around a circumferential portion 
thereof. A displaceable gear support member is provided that is 
displaceable in a direction having a lateral component with respect to the 
first shaft axis between an engaged position and a disengaged position. A 
biasing assembly biases the displaceable gear support member toward the 
engaged position. A second gear is carried by the displaceable gear 
support. The second gear has second gear teeth mounted around a 
circumferential portion thereof. The second gear teeth and the first gear 
teeth mesh when the displaceable gear support member is in the engaged 
position. At least one of the first and second gear teeth defines a tooth 
profile that is angled to produce a separating force in response to torque 
transfer between the first and second gears for moving the displaceable 
gear support member to the disengaged position to thereby limit torque 
transferred between the first and second gears and to the fastener. 
In operation, the first and second gears, which have respective first and 
second axis of rotation, are positioned such that the first and second 
axes of rotation are substantially parallel. The angled tooth profile on 
at least one of the first and second gears produces a separating force 
having a laterally directed component with respect to the first and second 
axes of rotation and arising between the first and second gears during 
transfer of torque between the first and second gears. The second gear is 
biased into meshing engagement with the first gear and the gears are 
rotated to apply torque to the fastener until the separating force 
overcomes the bias and separates the first and second gears to limit 
torque transfer between the first and second gears. 
An object of the present invention is to provide an improved torque driver. 
Another object of the present invention is to provide a torque driver that 
will tighten or remove one or more fasteners with controllable torque. 
Yet another object of the present is to provide a torque driver that is 
adaptable to a variety of fastener configurations. 
A feature of the present invention is a laterally displaceable spur gear. 
Another feature of the present invention includes angled teeth used to 
produce a separating force to thereby move the laterally displaceable 
gear. 
Yet another feature of the present invention is a coiled output shaft to 
drive a fastener. 
An advantage of the present invention is an uncomplicated, economical 
construction. 
Another advantage of the present invention is a construction that allows 
the driver to be adapted to a wide variety of fastener configurations. 
Another advantage is the ability to provide different and controllable 
torque to different fasteners within the same fastener configuration. 
Yet another advantage is a reduced time to remove multiple fasteners. 
Other objects, features and intended advantages of the present invention 
will be readily apparent by the references to the following detailed 
description in connection with the accompanying drawings and claims.

While the present application specifically claims embodiments shown in FIG. 
1-4, and FIG. 9-10, the remaining figures include information necessary 
for a complete understanding of the invention and the possible variations 
of embodiments which the claims are intended to describe. Thus, claims 
directed to am driver with gears displaceable in a direction having a 
lateral component are not intended to exclude all devices which may have 
an axial or parallel component of movement between the gears. FIG. 6-8A 
show a purely axial or parallel movement between gears with respect to 
their gear axes and the embodiments of the present invention may be 
modified in accordance thereto to include some axial or parallel component 
of movement as will be understood by those skilled in the art after 
studying the teachings of this specification. As well, various biasing 
systems such as the biasing system described in FIG. 5 may be used with 
the present invention. 
Thus, while the invention will be described in connection with the 
presently preferred embodiments, it will be understood that it is not 
intended to limit the invention to these embodiments. On the contrary, it 
is intended to cover all alternatives, modifications, and equivalents as 
may be included in the spirit of the invention. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention relates to an improved torque driver mechanism 
operable to transmit a precisely controllable degree of torque to a driven 
member such as a nut, screw, or the like. The torque driver may receive an 
input torque which is greater than a desired output torque and is operable 
to limit the input torque to the desired output torque level. 
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) shafts neither parallel nor 
intersecting but skew. 
While the present specification specifically claims embodiments shown in 
FIG. 1-4, and FIG. 9-10, the remaining figures include information 
necessary for a complete understanding of the invention and the possible 
variations of embodiments which the claims are intended to describe. Thus, 
claims directed to a driver with gears displaceable in a direction having 
a lateral component are not intended to exclude all devices which also 
have an axial or parallel component of movement between the gears. FIG. 
6-8A show a purely axial or parallel movement between gears with respect 
to their gear axes and the embodiments of the present invention may be 
modified in accordance thereto to include some axial or parallel component 
of movement as will be understood by those skilled in the art after 
studying tile teachings of this specification. 
The basic gear forces involved in operation of a torque driver in accord 
with the present invention are best described in connection with FIG. 1 
wherein gear teeth 12 and 14, on respective gears 13 and 15, are shown in 
some detail. Respective gear teeth 12 and 14 provide a positive drive, 
maintaining exact velocity ratios between pinion or driver gear 13 and 
driven gear 15 to positively rotate one fastener, or more than one 
fasteners simultaneously, up to the desired torque. 
Pitch circles, 16 and 18, are generally defined as the circles whose 
periphery is the pitch surface, or surface of an imaginary cylinder that 
would transmit by rolling contact, the same motion as toothed gears 13 and 
15. Motion transmitted between gears 13 and 15 is similar to that of 
rolling surfaces identical with the gear pitch surfaces, but the action of 
gear teeth 12 on gear teeth 14 is generally a combination of rolling and 
sliding motion. 
The radial distances between bottom lands 24, 26 and respective pitch 
circles 16, 18 is referred to as the respective dedendums. Circles 28, 30 
are the base circles of pinion 13 and driven gear 15 that are generally 
defined as the circle from which an involute tooth curve is generated. The 
addendum circle (not shown) is the circle connecting the top lands 32, 33 
of teeth 12, 14 and the corresponding radial distance to pitch circles 16, 
18 is the addendum. Faces 35, 37 are the surfaces of teeth 12, 14 radially 
outwardly of pitch circles 16, 18. Flanks 39, 41 are the surfaces of teeth 
12, 14 radially inward of pitch circles 16, 18. 
Pitch point 38 is the point at which pitch circles 16 and 18 are tangent 
and this is typically the only point where contact between the teeth is 
pure rolling contact depending on the teeth profiles which may be of 
numerous types or modified types including involute, involute stub tooth, 
cycloid, American Standard spur gear tooth forms, and the like, made by 
different methods including hobbing, shaping, milling, preshaving, and the 
like. 
Each pair of teeth has its points of contact co-linear with pressure line 
36. The angle .phi. between pressure line 36 and tangent line 40 is the 
pressure angle. Force P is the reaction force on bearings of pinion 13 and 
force D is the reaction force on bearings of driven gear 15. Force N is 
the force normal to tooth profiles at the pitch line. Force T is the 
tangential or driving force. Force R is the radial or separating force. 
While tangential force T is used to produce output torque, radial force R 
is often considered a wasteful byproduct. However, force R is used to 
control output torque by automatically disengaging the gear at a specified 
torque. 
When the fastener is tightened to the specified torque, the radial force R 
at the engaged teeth equals a bias force, discussed hereinafter that urges 
pinion 13 and driven gear 1.5 into engagement. Any higher torque causes 
gears 13 and 15 to move laterally away from each other in this embodiment 
of the invention. 
As gears 13 and 15 move laterally away from each other, pressure angle 
.phi. typically increases depending on the gear teeth profile (such as the 
frequently used involute or modified involute gear teeth profiles) causing 
a decrease in tangential force T (and output torque) and an increase in 
radial force R to thereby facilitate additional displacement. Thus, the 
separation process typically accelerates to completion rapidly after it 
first begins. 
After gears 13 and 15 are displaced by the working depth (sum of the 
addendums of the teeth 12 and 14), pinion 13 is disengaged. Pinion 13 
continues to turn and biasing will cause pinion 13 to re-engage with the 
next set of teeth. The process of displacement and disengagement continues 
until input torque is removed. In this manner, the torque applied to the 
threaded fastener is limited to the specified torque. 
FIG. 2 and 3 show how this principle is applied for use with spur gear 
driver 10. Spur gears are generally considered to be those gears that 
transmit torque between parallel shafts and may have straight teeth 
parallel to the gear axis or helical or herringbone teeth patterns and may 
include external, internal, and rack and pinion type configurations. Gears 
50 and 52 are external spur gears with teeth 54 and 56 which point 
outwardly from shafts 58 and 60, respectively. Gears 50 and 52 and other 
components discussed hereinafter are preferably mounted in driver housing 
61 with antifriction bearing assemblies such as ball-bearing assemblies 64 
or other types of antifriction bearing assemblies as desired. Various 
bearing assemblies may be used with the rotating components as desired. 
Thus, while various sliding surfaces may be shown or discussed herein 
without specifying types of antifriction bearings, or indicating the 
presence of bearing surfaces in the associated drawings, it will be 
understood that those skilled in the art will be aware of the need to 
supply tile same where desired. 
As well, various types of lubrication may be used for any sliding surfaces 
discussed or shown herein. For instance, self-lubricated teflon coated or 
impregnated bronze surfaces may be used for relatively sliding components. 
Other suitable coating materials could be used for self-lubricated 
surfaces on the various components shown and discussed herein as are known 
to those skilled in the art. Those skilled in the art will recognize that 
many methods for lubricating any relatively sliding surfaces that are 
discussed herein. For instance, the various chambers and suitable elements 
may be flooded with oil. Pneumatic biasing systems, as discussed 
hereinafter, may be circulated through oil baths for air lubrication. It 
is also to be understood that antifriction means include lubricants and 
self-lubricating materials that may be used on the various relatively 
sliding components discussed and shown herein. 
Input shaft 58 is preferably connected to an input torque source (not 
shown) that supplies torque at a higher level than the preferred specified 
output torque limit from shaft 60. The input torque source may include a 
manual ratchet wrench, electric drill, pneumatic motor or the like. Output 
shaft 60 is connected through flexible linkage or coupling 66 to output 
shaft attachment 68 which is then coupled to a fastener (not shown). 
Flexible linkage 66 preferably has a coil configuration that is flexible in 
all directions and may be obtained commercially with specified coil 
configurations, windup, spring rates, special end connections, axial 
offsets, bending angle features, and other specified features, from 
companies such as Helical Products Company, Inc. Flexible linkage 66 could 
also be provided with U-joints and constant velocity splines (not shown), 
or other linkage components including combinations of components including 
a coiled linkage as desired. However, coiled linkage 66 is presently 
preferred for simplicity, lower cost, and ease of construction and 
maintenance. As well, flexible linkage 66 may be disposed fin an angled, 
rounded, or other configuration as desired to tighten fasteners located in 
difficult to reach positions. 
Driven gear 52 and shaft 60 are mounted for rotation in displaceable 
support member 70. Displaceable support member 70 is laterally 
displaceable in a direction transverse to input shaft axis 72 which, in 
this embodiment, is parallel to output shaft axis 74. Displaceable support 
member 70 moves laterally with respect to pinion 50 within chamber 71 of 
driver housing 61 between an engaged position and a disengaged position 
shown, respectively, in FIG. 2 and FIG. 3. Displaceable support member 70 
may have various cross-sectional shapes such as, but not limited to, 
circular, elliptical, or square shapes. 
Displaceable support member 70 and its related bearings 64 for supporting 
shaft 60 are loaded by compressed spring 76 to produce a biasing force 
that tends to move displaceable support member 70 towards pinion 50. To 
control the specified level of torque limit, the level of the bias, or 
other factors discussed hereinafter, may be adjusted. 
The required bias can be obtained from geometrical relationships using the 
gearing configuration that includes e.g. effective gear radius and 
pressure angle. Various sizes and combinations of gears may be selected 
based on the particular requirements, speed, and so forth of the 
application. Load adjustment shims 78 or other means such as a moveable 
adjustment plug (not shown) may be used to adjust the bias to the desired 
level. Thus, spring bias, or other types of bias, may be either preset or 
adjustable. 
A preset version can be used, for instance, with critical assembly 
operations where the operator needs only one torque setting. An adjustable 
version, which could be manually or automatically adjustable, could be 
used for a wider assortment of operations when multiple torque settings 
are needed. 
The input torque source (not shown) rotates input shaft 58 and also rotates 
pinion 50, which is secured to input shaft 58 for rotation therewith. When 
the fastener is tightened to the specified torque limit, the separating 
force at engaged teeth 54 and 56 equals the biasing force. Higher torque 
causes driven gear 52 to move laterally away from pinion 50. As driven 
gear 52 moves laterally away from pinion 50, the pressure angle increases 
as discussed hereinbefore, causing a decrease in tangential force T (and 
related output torque) and an increase in radial or separating force R to 
facilitate lateral movement of displaceable support member 70 toward a 
disengagement position shown in FIG. 3. 
After driven gear 52 is displaced by its working depth to disengage from 
pinion 50 as shown in FIG. 2, pinion 50 continues to rotate. Spring 
bias-76 then biases displaceable support member 70 to move driven gear 52, 
which is substantially no longer rotating, into engagement with the next 
set of teeth 54 on pinion 50. The process of displacement and 
disengagement repeats until input torque is removed. 
Flexible linkage 66 remains connected to the fastener throughout the torque 
sequence and adapts for movement of displaceable support member 70. 
Adapter 68 is preferably rotatably secured, with a bearing assembly 80, to 
driver housing 61 so that adapter 68 rotates but is axially fixed with 
respect to housing 61, at least in the embodiment of FIG. 2 and FIG. 3. 
Bearing assembly 80 may be of several types and shapes but is preferably 
used to prevent radial forces that could interfere with loading of 
displaceable support member 70 and thereby provide more accurate torque 
limiting action. See discussion of bearings and lubrication hereinbefore. 
The design selection of pinion 50 and driven gear 52 requires consideration 
of such factors as pressure angle, contact ratio (ratio of length of path 
two gear teeth are in contact to base pitch), teeth depth, radii, tooth 
profile, and the like chosen for the particular application. 
FIG. 4 and FIGS. 4A show a top view of alternative embodiment driver 10A 
that is substantially the same as driver 10 except for an alternative 
pneumatic biasing assembly 100. Components with substantially identical 
counterparts in driver 10 are labeled with an "A" suffix and reference may 
be made to the earlier discussion for those components so labeled. As with 
driver 10, displaceable support member 70A moves within cavity 71A between 
an engaged and a disengaged position. Cavity 71A has a first section 73 
that has a substantially consistent rectangular cross-section along its 
length in which a rectangular portion, as shown in FIG. 4A, of 
displaceable support member 70A moves. It will be understood that this 
cross-section could also be cylindrically, elliptically, or otherwise 
configured as desired. As with driver 10, cavity 71A also has an expanded 
portion 75 which allows lateral movement of driven gear 52A within cavity 
71A. 
Sealed cavity 102 is preferably cylindrically shaped and is preferably 
sealed with sealing elements such as 0-ring 104 and lubricated to reduce 
friction. As displaceable support member 70A moves between its engaged and 
disengaged position, the volume 105 of sealed cavity 102 and also cavity 
106 varies accordingly. Piston 108 is threadably secured to driver housing 
61A but is moveable relative to displaceable support member 70A. 
Passageway 110 through piston 108 interconnects cavity 102 to a preferred 
constant pressure pneumatic source, discussed hereinafter with respect to 
FIG. 5, to maintain a constant pressure within cavity 102 and thereby 
produce a constant biasing force on wall 112 of cavity 102. 
A constant pressure pneumatic biasing source of this type is inherently 
more accurate than a spring bias for several reasons. The spring bias 
tends to have a relatively larger tolerance variation in spring pressure 
over relatively short distances than a pneumatic bias assembly. 
As well, the spring bias increases and decreases with compression and 
expansion to adversely affect torque limiting accuracy. Even though the 
pressure angle between the gear teeth typically increases to thereby 
increase the radial or separating force after the desired torque is 
reached, the spring bias force also increases with respect to the bias 
force of the engaged position to inhibit the desired slippage operation 
between pinion 50 and driven gear 52. With a constant pressure bias, the 
movement towards the disengaged position occurs more rapidly. 
Thus, the constant pressure biasing assembly 100 produces a constant bias 
even as displaceable support member 70A moves laterally with respect from 
pinion 50A between an engaged position and a disengaged position. As the 
pressure angle changes and the radial force increases, the load on 
displaceable member 70A remains constant to correspond to the specified 
output torque. Preferably, a calibration record is obtained to measure 
cavity pressure versus output torque so as to provide an accurate 
calibration of each machine. Thus, torque control level may be set with a 
sufficiently accurate pressure gage having sufficient resolution to be 
calibrated in terms of the desired torque limit and tolerance required 
thereof. 
Various configurations of pressurized cylinder-piston assemblies with 
related seals and shafts may be used with that shown in FIG. 4 being a 
presently preferred configuration. The bias force produced to act against 
displaceable support member 70A is a function of piston/cylinder geometry 
(e.g. internal diameter and pressure). Maintaining a constant pressure in 
the cylinder ensures that during lateral displacement of gear 52A towards 
or away from pinion 50A, the bias will always remain at the preset level 
which corresponds with the specified torque output. 
FIG. 5 discloses a schematic of a self-venting pressure regulator system 
130 that relieves downstream pressure at two different desired setpoints 
for applying different, but readily adjustable, torque limits to different 
threaded fasteners in a configuration of fasteners. The multiple fastener 
torque drivers shown in FIG. 9 and FIG. 10 are examples of drivers that 
may require such adaptability. System 130 could also be used to supply 
constant pressure to a single driver such as that of FIG. 4 or FIG. 8 or 
could be modified to provide for more than two different torque limits if 
desired. Safety devices such as relief valves (not shown) may be used 
therein as desired e.g. in the supply line. 
Pressurized air enters inlet 132 and is regulated by first check valve 134. 
Pressure indicated at first pressure gage 136 will preferably be higher 
than subsequent output pressures at outlets 1 through N. Adjustable 
self-venting pressure regulator 138 may be used in conjunction with gage 
136 to set a desired pressure corresponding to a desired torque level at 
outputs 1 through I one of which could be connected, for instance, to 
passage 110 of FIG. 4. The letter I indicates that as many connections as 
desired up to the limits of the system may be used. 
To obtain a second selective torque limit, the pneumatic line branches at 
142 to second check valve 144. The output of second check valve 144 goes 
to second adjustable self-venting pressure regulator 146 that may be 
adjusted in accord with gage 148 to obtain a Second pressure output at 
outputs I+1 to N. While system 130 is a particular pressure supply system, 
other systems may also be used. The outputs of system 130 may be ramped, 
sequenced, or otherwise varied to control torquing of fasteners in a 
desired manner. Even while pressure is relatively slowly ramped, it will 
be understood that the pressure within a piston/cylinder assembly remains 
substantially constant during the short time in which a laterally or 
axially displaceable gear moves from an engaged to a disengaged position. 
FIG. 6 and FIG. 7 discloses a conical or bevel gear driver 160 having an 
adjustable bias configuration. Driver 160 operates on a similar principle 
as that illustrated in FIG. 1 of loading a displaceable gear to control 
output torque. However, the bevel gear configuration of driver 160 has an 
axial load scheme such that the displacement occurs axially, with respect 
to a gear shaft axis, rather than radially with respect to a gear axis, as 
with the spur gear arrangement. In the embodiment illustrated, the input 
gear or drive gear is displaceable rather than the output or driven gear. 
Bevel or conical gears are normally those which may be used to change the 
shaft axis direction or to change shaft speed as well as direction. Bevel 
gears include many variations such as external bevel gears, internal bevel 
gears, crown gears, straight,bevel gears, spiral bevel gears, zero bevel 
gears, and the concept of operation of this embodiment of the invention, 
as discussed hereinafter, could conceivably be developed with hypoid gears 
and worm gears which are therefore also considered, for the purposes of 
this application, to come under the general term of bevel gears. 
Bevel driver 160 includes three basic gear assemblies including 
displaceable gear 162, intermediate gears 164, and output gear 166. 
Displaceable gear 162 is axially displaceable in a direction parallel to 
axis 168 of input shaft 170 and axis 172 of output shaft 174. Displaceable 
gear 162 is biased into engagement with intermediate gears 164 by biasing 
spring 176. Key 163, shown also in FIG. 6B, rotationally secures 
displaceable gear 162 with respect to input shaft 170 but permits axial 
movement therebetween. Thrust bearing 167 is preferably connected to the 
lower end of shaft 170 for support, to reduce play, and to reduce friction 
between shaft 170 and disc 180 during rotation. 
While gear 162 is shown as a monolithic component, it could be comprised of 
an assembly of components including bearings, discs, and so forth. The 
gear train of the bevel gear driver 160 could also be arranged so as to be 
angled if desired as may be necessary to apply torque to fasteners located 
in difficult to reach positions. 
The components of driver 160 are mounted within cylindrical driver housing 
178. Various types of bearings may be used between driver housing 178 and 
any movable components such as in the gear train as well as between the 
shafts and the supporting members (see general discussion of bearings and 
lubrication above). 
Shafts 165, shown also in FIG. 6C for intermediate bevel gears, are 
preferably held in their respective positions with respect to driver 
housing 178 i.e. their associated shaft axes are fixed with respect to 
driver housing 178. They may be pinned to driver housing 178, held by 
internal slots within driver housing 178, or otherwise affixed thereto. As 
well, disc 180, which supports intermediate gears 164 and their related 
shafts 165, may be fixed by pins or other means to secure disc 180 in 
position with respect to driver housing 178. Because the axes of shafts 
165 are fixed with respect to housing 178, bevel gears 164 may be used to 
rotate output gear 166 via output gear teeth 169 (see FIG. 6C) in response 
to rotation of displaceable input gear 162. Thrust bearing 167 may be 
provided to reduce friction and play between disc 180 and shaft 170. 
Cap 182 holds the internal components of driver 160 within driver housing 
178 and may be threadably secured thereto, as shown, with fine adjustment 
micrometer type threads 184. Fine adjustment threads 184 allow bias, and 
therefore torque limit, to be adjusted by rotation of cap 182. Driver 182 
may be calibrated so that torque indication marks 186 provide a direct 
reading of the selected torque limit for driver 160. Lock nut 188, or 
other locking means, may be used to fix cap 182 with respect to driver 
housing 178 and maintain a selected torque limit. 
Driver 160 also includes axial load control or clutch assembly 200 that 
comprises input attachment 202, attachment housing 204, axial load control 
spring 206, and splined drive disc 208. As shown in FIG. 6A, spline-groove 
interfaces 210 between drive disc 208 and attachment housing 204 are 
engaged to transmit torque to input shaft 170. The spline-groove 
interfaces disengage in the manner shown in FIG. 7A to prevent torque 
transmission if axial force applied, as by an operator, is greater than a 
selected amount. As discussed hereinbefore, spline-groove interfaces 210 
may be self-lubricated or otherwise lubricated as desired. 
Input shaft 170 is fixably secured to drive disc 208 by means not shown 
such as welds, pins, threads, snap-rings, or other means. Axial load 
control or clutch assembly 200 therefore acts to prevent excessive axial 
load being applied to the fastener through driver 160. Excessive axial 
load could alter bias applied with spring 176 to thereby change the 
selected torque limit. 
If the axial load is greater than a selected amount, attachment housing 204 
moves towards cap 182 to thereby disengage drive disc 208 with respect to 
attachment housing 204 as shown in FIG. 7A. This action prevents torque 
transmission to shaft 170. As well, it is noted that clutch 200 could be 
positioned elsewhere along the shaft and gear assembly prior to connection 
with fastener 212 to prevent torque transmission to fastener 212. 
In operation, torque applied through input shaft 170 is transmitted through 
output shaft 174 to fastener 212. If an operator presses too hard on the 
fastener 212 with driver 160 then clutch 200 disengages torque to prevent 
any torque transmission to fastener 212. Otherwise, torquing of fastener 
212 continues until a desired torque limit is reached as indicated by 
calibration marks 186. At that point, displaceable gear 162 moves upwardly 
with respect to intermediate bevel gears 164, as shown in FIG. 7, to a 
disengaged position. The next set of teeth on displaceable gear 162 will 
then re-engage bevel gears 164 due to bias spring 176, or other bias 
mechanism, and the process repeats until torque is removed from input 
attachment 202. 
FIG. 6C shows four bevel gears with a fixed and equidistant circumferential 
spacing with respect to driver housing 178 and driven gear 166. Other 
numbers of bevel gears could be selected based largely upon the 
anticipated torque-related stress to be carried by each of bevel gears 
164. Thus, in some applications three bevel gears in an intermediate bevel 
gear assembly may be sufficient to handle the anticipated torque 
requirements. The multiple number of bevel gears 164 provide additional 
durability because wear between the multiple gears carrying the torque 
reduces wear which would otherwise occur between a single driver-driven 
gear arrangement. 
In addition to increasing torque adjustment accuracy, the bevel gear 
assembly is relatively inexpensive, is easy to manufacture, and provides 
opportunity for considerable flexibility of tooth profile design for the 
intended slippage type operation and/or for angled operation of the 
driver. 
FIG. 8 provides an alternative bevel gear driver configuration 160A with 
pneumatic biasing assembly 230. Pressurized cylinder sleeve 232 contains 
pressurized fluid, preferably gas held at a constant pressure in variable 
volume cavity 233, as discussed hereinbefore, to produce a biasing force 
against piston 234. Piston 234, in turn, acts against displaceable gear 
162A in the manner discussed hereinbefore. Seal 236, an 0-ring seal, or 
other types of seals may be used to seal cavity 233 from air leakage. For 
instance, grease from grease inserts, grease wicks, or other sources may 
act to form suitable seals and simultaneously lubricate relatively close 
fitting bearing surfaces around shafts 170A and 174A. 
Pressurized gas preferably passes through passageway 238 of connector 240 
to cavity 233. For best accuracy, pressurized gas will be from a constant 
pressure regulated air supply, such as system 130 shown in FIG. 5, or 
other constant pressure regulated fluid supply systems. A sufficiently 
accurate pressure gage may be calibrated and operated with a vented 
pressure regulator to set driver 160A at a desired torque limit. 
As explained hereinbefore with respect to driver 10A shown in FIG. 4 and 
FIG. 4A, a constant pressure used with a pressurized cylinder, as shown in 
FIG. 8, creates a constant bias that is more accurate than a spring bias. 
The spring bias increases with distance and may also have significant bias 
force tolerances that limit accuracy and thereby affect the desired torque 
level. 
FIG. 8A discloses another alternative bevel gear driver arrangement 160B 
wherein the intermediate bevel gear assembly is absent but which includes 
a torque limit adjustment mechanism as may be conveniently hand-held. This 
embodiment may relate to consumer oriented specifications which may not 
require the long lasting features for only occasional or hobby usage. 
Upper gear 162B directly drives output gear 166B to thereby rotate output 
shaft 174B up to the torque limit as discussed above. Thrust bearing 167B 
may be used in the manner discussed hereinbefore. While it is desirable to 
include the intermediate bevel gear assembly for the reasons discussed 
above, it is also possible to provide a selectable torque nut driver for 
removing or tightening fasteners without that assembly. As with the other 
configurations, the bevel gear driver of FIG. 8A may be used with a 
battery driven electric motor as may be conveniently hand held. This 
configuration could also be used with a pneumatic motor and include the 
pneumatics biasing assembly 230 discussed above as may be more desirable 
for shop use. Other similar configurations and arrangements in accord with 
the teachings herein as will be apparent to those skilled in the art. 
FIG. 9 and 9A show a multiple fastener driver 250 that may be used to drive 
multiple fasteners 252 for simultaneous tightening or loosening. Socket 
255 may be adapted to include fastener storage and control means (not 
shown) for storing and controlling multiple nuts 252 and 253 as might be 
removed from four tires for subsequent reinstallation. As will be 
appreciated, simultaneous removal of fasteners could save significant 
time, for instance, in a business that changes out large numbers of tires 
each day. If desired, socket 255 could be a standard socket that receives 
only a single nut 252. 
Driver 250 may be used to drive fasteners 252 in the same configuration to 
different selectable torque levels by coupling plugs, such as coupling 
plugs 254 and 256, to pressurized gas or fluid at different pressures as 
may be obtained from system 130 of FIG. 5. The pressurized gas supply 
obtained from system 130 may also be ramped during the nut driving process 
to limit torque applied to any particular nut in a fastener configuration 
to thereby verify that all fasteners are limited to the same torque at all 
times--a feature that overcomes a problem with prior art devices. It will 
be noted as discussed hereinbefore, that a ramped pressure remains 
substantially constant during the short time period in which a moveable 
gear, such as output gear 262, moves from an engaged position to a 
disengaged position. A sequencer (not shown) could be used to specially 
sequence the order of fastener installation by controlling, for instance, 
the bias from system 130. 
The basis of operation of driver 250 is similar to that of driver 10 and 
10A shown in FIG. 2-FIG. 4. Input torque is applied to shaft 258 and 
pinion 260. Pinion 260 drives each output gear 262 at the same rate to 
thereby torque multiple fasteners 252 simultaneously as may be required 
for some applications. Each output gear 262 is carried by an associated 
displaceable gear support member 264 moveable within a respective support 
member cavity 266. 
Coiled flexible drive shafts 268 each individually adjust to lateral 
movement of the respective output gears 262. Shaft connector members 270 
are preferably rotatably secured to outer leg housing 272 and inner leg 
housing 271 by intermediate bearing members 273 which may be of various 
types. Intermediate bearing members 273 isolate radial forces on flexible 
coupling 268 and 292 to prevent interference with displaceable gear 
support 264 control loading. Inner and outer leg members 271 and 272 are 
substantially cylindrical (see FIG. 9A) in the present embodiment but 
could be separate leg members for each fastener shaft 268. Hole 281 may be 
included to allow torquing operation around a centrally located shaft. 
Driver 250 also includes a gauged selector mechanism 280 shown more clearly 
in FIG. 9A which is a cross-section of FIG. 9 along the line 9A--9A. 
Gauged selector mechanism 280 allows driver 250 to be used with more than 
one fastener configuration by movement of fastener adapters 290. 
For this purpose, ring 282 is rotatable via control handle 286 to move 
translatable blocks 284 laterally inwardly or outwardly. Output adapters 
290 are then also movable within slots 288 in end member 294 as indicated 
in FIG. 9A. Antifriction bearings 285 are preferably used to rotatable 
secure output adapters 290 in translatable blocks 284. As discussed herein 
before, various lubrication means are preferably provided between moving 
parts such as blocks and other sliding or rotating surfaces. Flexible 
coiled fastener drive shafts 292 flex as required to adjust shaft length 
and orientation to compensate for movement of output adapters 290. Other 
types of shaft linkage such as universal joints could be used in place of 
or in conjunction with flexible coiled shafts 268 and 292 as discussed 
hereinbefore. 
Ring 282 is supported by end member 294 that is secured to outer leg 
housing 272 with connectors 298. Bias springs 296 bias translatable blocks 
284, having curved guide surfaces 300, to move along inner ring cam 
surfaces 302 that determine the lateral orientation of fastener adapters 
290. Guide and cam surfaces 302 and 300 may have various shapes as 
desired. Preferably there is a single point interaction between the 
surfaces so that translatable blocks 284 follow cam surface 302 more 
readily. Control handle 286 moves in slot 304 of end member 294 which may 
be calibrated or marked as desired for various lateral orientations. While 
end 303 is shown as a point, it could also be square shaped, round or 
otherwise shaped. Other adjustment mechanisms, such as individually 
adjustable gauge selector members (not shown) could also be used. Other 
adjustment paths for fastener adapters 290 defined herein by slots, such 
as slots 288, could also be used. 
FIG. 10 provides another driver 350 embodiment suitable for torquing 
fasteners in non-circular fastener configurations such as might be 
suitable for manifold fastener configurations. While various types of gear 
drives could be use, this particular embodiment Uses inner pinion 352 may 
be used for torque input to drive output gears 353 and to transfer torque 
via idler gears 354 to outer pinions 356 which, in turn, drive output 
gears 358. Other drive means could be used. For instance, a centrally 
disposed elongate worm gear could be used as the principal torque input 
and transfer means. Such a worm gear could extend across driver 350 from 
each gear 356 in place of the present gear chain and would tend, at least 
in this embodiment, to reduce or eliminate gear chatter noise. 
As discussed hereinbefore, each output gear 358 is laterally displaceable 
within a chamber 362 and is supported with displaceable gear support 
member 364. Fasteners may be simultaneously rotated up to a desired torque 
limit. The torque limit may vary, it may be ramped, or otherwise 
controlled as desired between fasteners in the same configuration as 
discussed hereinbefore. Each air connector 360 is preferably connected to 
a constant pressure pneumatic supply system such as system 130 shown in 
FIG. 5 for biasing each respective gear support member 364. 
In general, in the various torque drivers discussed, the gear teeth on one 
or both gears may be modified so as to be short, stubby, and/or rounded to 
further facilitate this operation as desired. As well, for high speed 
operation, means could be used to completely disengage the gears after the 
specified torque is reached and displacement begins if this was desired. 
However, design of short, stubby, teeth may be more economical than a 
kick-out mechanism or other such means. 
The foregoing disclosure and description of the invention is illustrative 
and explanatory thereof, and it will be appreciated by those skilled in 
the art, that various changes in the size, shape and materials as well as 
in the details of the illustrated construction, reliability 
configurations, or combinations of features of the various torque driver 
elements of the present invention may be made without departing from the 
spirit of the invention.