Friction clutch hand tool

A friction clutch hand tool in the style of a socket wrench for tightening and loosening common mechanical fasteners. Socket may be received from either side into a cylindrical opening through the wrench head. Once received inside the head, socket is gripped by rollers held captive within notches provided in cylindrical wall of opening in wrench head. Rollers grip outside surface of socket directly. Rotation of head relative to socket causes rollers to roll up ramps out of notches and wedge tight against socket, thereby simultaneously imparting torsion to fastener while clamping socket down on fastener. Socket may be assembled around fastener from multiple interlocking pieces. Socket may also be hollow.

INTRODUCTION AND BACKGROUND OF THE INVENTION 
This invention relates to a friction clutch hand tool in the style of a 
socket wrench for use in tightening and loosening conventional mechanical 
fasteners. While the preferred embodiment herein is directed to use of the 
tool on a common hexagonal fastener, there is no limitation on the shape 
of the fastener that this tool can be applied to, so long as the internal 
shape of the socket matches that of the fastener. The only limitation on 
the application of this tool is that the fastener must have an outer 
surface that is physically susceptible to receiving a female socket to 
tighten or loosen it. 
Friction clutch socket wrenches are generally well known in the art. See, 
e.g., Korty, U.S. Pat. No. 5,086,673; Cartwright, U.S. Pat. No. 4,669,339; 
Seablom, U.S. Pat. No. 3,621,739; and Pratt, U.S. Pat. No. 2,469,572. In 
order to harness a friction force, however, these previous inventions have 
utilized multiple roller and spring systems that bear against pins and 
stops strategically located in a complex wrench assembly. Previous 
inventions have also consistently brought the friction force to bear on a 
member that is encased within the wrench assembly. A conventional socket 
is then connected to this member by means of a traditional square drive. 
The present invention improves on the prior art in several respects. It 
consists of a wrench driving a socket that is split into two or more 
pieces along its cylindrical axis. The wrench slides over the outside 
circumference of the assembled socket. Its improved design uses the torque 
applied to the wrench by the user to provide circumferential friction 
directly to the outside surface of the socket. A traditional square drive 
connection to the socket thus becomes unnecessary. The split socket 
provides improved access to fasteners in locations that would otherwise be 
hard to reach. The split socket also provides improved grip on the 
fastener when used in conjunction with the wrench, since the wrench tends 
to clamp and compress the socket over the fastener when in use. The tool 
as a whole operates on a fastener to which a wire or cable is attached 
without first having to disconnect that wire or cable. The simple design 
of the tool as a whole facilitates manufacture. The novel design of the 
wrench obviates the need for a mechanical direction selector to set 
whether torsion will be applied to the socket in a clockwise or 
counterclockwise direction. Instead, the wrench is capable of receiving a 
socket from either of two opposite sides, and the side from which the 
socket is received dictates the selected direction of torsion. 
BRIEF SUMMARY OF THE INVENTION 
One object of the present invention is to provide improved access to 
fasteners found in awkward or congested locations. As noted, the invention 
provides a socket that is split along its cylindrical axis into two or 
more interlocking pieces. This split-socket feature is apparently unknown 
in the prior art. Being in two or more pieces, the socket provides 
dramatically improved access to a fastener. Instead of placing a 
traditional socket over the end of a component held by the fastener, the 
user assembles the pieces of this socket around the fastener. Only 
approximately 3/4" clearance is then required at the end of the component 
to bring the wrench in and slide it over the interlocked pieces of the 
socket. The socket is ideally split into equal and identical pieces so 
that the pieces are interchangeable in relative position when assembled 
around a fastener. This feature will facilitate manufacture and operation. 
The pieces of the socket may also be magnetically charged so that when 
brought together over a fastener, they will remain there by themselves 
while the wrench is slid over them. 
Another object of the invention is to improve the grip on a fastener by a 
socket. This feature will increase the potential life of the fastener and 
enhance the personal safety of the user of the wrench. Traditional sockets 
tend to "round off" the fiat faces of a fastener because the fastener's 
resistance to the torque being applied causes the end of the socket to 
enlarge marginally in diameter. This effect in turn causes the socket to 
distort the shape of the fastener, especially at the corners where the 
flat faces of the fastener meet. Eventually there is play between the 
shape of the socket and the shape of the fastener, play that causes the 
socket to "slide over" the fastener as torque is applied. This type of 
failure between the socket and fastener will usually shorten the effective 
life of the fastener. Further, because failure can occur catastrophically 
and while the user is applying considerable torque, the user can be 
exposed to injury. The frequency of this type of industrial accident is 
well documented. 
This invention will counteract both of these effects. As torque is applied, 
the wrench constricts diametric enlargement of the socket as the needle 
rollers within the wrench bear directly upon the socket to gain 
circumferential friction. Further, the split in the socket provides 
marginal displacement of its overall shape in response to the radial 
forces placed upon it by the rollers in the wrench. This in turn tends to 
conform the shape of the socket to the shape of the fastener and take up 
any play existing between the two. 
Another object of this invention is to provide a hand tool capable of 
installing and removing screw-in components to which wires or cables are 
attached without first detaching the wire or cable from the component. 
This invention provides this feature by being hollow along the cylindrical 
axis of the socket. The socket is first placed over the component by 
attaching each half of the socket from opposite sides. The wire or cable 
attached to the component is then threaded through the hole in the wrench. 
The wrench can then be placed over the socket and the fastener rotated 
without distressing the wire or cable. 
A friction clutch socket wrench with this hollow axis feature is apparently 
unknown in the prior art. The feature also serves a long-felt but unsolved 
need in the automobile industry to install or remove components such as 
oxygen sensors on exhaust manifolds. These components are almost 
universally very awkward to access. Further, such components typically 
have a wire permanently attached by a special metallurgic process, which 
connection, if damaged, renders the component completely unserviceable. 
Specialized one-piece sockets are known in the industry that provide 
notches or grooves in their inside walls to accommodate the wires. Such 
sockets are not effective because they do not solve the access problem, 
and because the notches or grooves in the socket rotate with the socket as 
it is turned, causing distress to the wire and its connection to the 
component. The present invention solves immediately both the access 
problem and the wire connection protection problem presented in the 
installation and removal of these components. 
Another object of this invention is to provide a simplified and improved 
design of a wrench that will apply circumferential friction directly to 
the outside surface of a cylindrical socket to give both clockwise and 
counterclockwise torsion. The invention provides a wrench that simply 
slides over the socket. A plurality of needle rollers bear directly upon 
the outside circumferential surface of the socket and provide friction 
directly to that outside surface. When torque is applied to the wrench, 
these rollers roll synchronously up ramps to impose a circumferential 
friction on the socket that translates into torsion on the fastener. This 
method of applying friction directly to the outside surface of a socket 
through rollers synchronously travelling up identical ramps is apparently 
unknown in the art. 
Further, the prior an consistently discloses mechanically complicated 
devices with many intricate cooperating parts. This makes them difficult 
to manufacture and maintain, as well as potentially unreliable. In 
contrast, this invention discloses a plurality of simple needle rollers 
held captive in recesses in the wrench by an equal number of springs and 
one cylindrical roller cage. The advantages of this simple design to ease 
of manufacture and to potential reliability are self evident. 
Further, all friction clutch wrenches in the prior an disclose some type of 
mechanism to reverse the direction of operation manually. The present 
invention provides a wrench that is symmetrical about the plane of its 
opening, and is thus capable of receiving a socket from either side. This 
provides for clockwise torsion (and corresponding counterclockwise free 
revolution) when a socket is received from one side, and vice versa when a 
socket is received from the other side. This feature obviates the need for 
a manual switch or selector mechanism to reverse the direction of 
operation of the wrench. A friction clutch socket wrench that reverses 
direction of operation simply by receiving a socket from the other side is 
apparently unknown in the art. This feature also makes the wrench 
immediately more efficient to manufacture and use. 
These and other objects of the present invention will be apparent to those 
skilled in this art from the detailed description of a preferred 
embodiment of the invention set forth below.

DETAILED DESCRIPTION OF THE INVENTION 
As summarized above, this invention is directed to a friction clutch hand 
tool that tightens or loosens a fastener in the style of a socket wrench. 
The tool provides a wrench that imparts torsion to the fastener through 
direct friction grip of the outside cylindrical surface of a multipieced 
socket assembled over the fastener. The tool provides, among other 
benefits, improved access to hidden fasteners, improved grip on the 
fastener when imparting torsion, and the ability to tighten or loosen a 
fastener to which a wire is attached without first having to remove the 
wire. These features will in particular address a long-felt but unsolved 
need to install or remove oxygen sensors located on the exhaust manifolds 
of modern automobiles without removing or damaging the wire 
metallurgically connected to these oxygen sensors. 
The invention is shown in perspective in FIG. 1 and FIG. 2. Wrench 10 has a 
head 11 connected to a handle 12 by a hinge pin 13. The location of hinge 
pin 13 is such to provide rotation of handle 12 about head 11 in a plane 
perpendicular to the plane of normal operation of the wrench. As shown in 
more detail in FIG. 3 and FIG. 5, handle 12 also contains a hemispherical 
detent 14, while head 11 contains a cylindrical recess 15. A helical 
detent spring 16 and a steel detent ball 17 are received into cylindrical 
recess 15. Cylindrical recess 15 and hemispherical recess 14 are then 
located in the connection of head 11 to handle 12 so that detent ball 17 
is held captive in hemispherical detent 14 by detent spring 16 when handle 
12 is in normal operating position about head 11. This arrangement allows 
handle 12 to "click" into normal operating position, and remain there 
until specifically required to be operated from a different angle. 
FIG. 1 also shows a plurality (preferably 2) of identical socket pieces 18 
that interlock to provide a hollow cylindrical socket 19. Either or both 
ends of assembled socket 19 provide a drive recess 20 to match the outside 
shape (usually hexagonal) of a mechanical fastener. FIG. 2, FIG. 3 and 
FIG. 4 show socket 19 assembled to provide a single hexagonal drive recess 
20 at one end. As shown in section on FIG. 5, socket pieces 18 contain 
uniform locating lugs 21 at their points of interlock to aid assembly. 
Wrench head 11 contains a cylindrical opening 22. As shown in section on 
FIG. 3 and FIG. 4, the diameter of opening 22 is reamed out at both ends 
to give identical and slightly larger cylindrical recesses 23 at both 
entrances to opening 22. Recesses 23 contain grooves 24 in their 
circumferences. FIG. 5 shows the inside surface of opening 22 in section, 
wherein it can be seen that opening 22 also provides a plurality 
(preferably 6) of identical notches 25 spaced equally around its 
circumference. Returning to FIG. 3 and FIG. 4., notches 25 can be seen to 
extend along the inside surface of opening 22 in a direction parallel to 
the cylindrical axis of opening 22. Notches 25 do not extend all the way 
through opening 22, however, leaving portions of unnotched circumference 
26 at both ends of opening 22. FIG. 5 shows the cross-sections of notches 
25 as identical, providing a sharp cutout 27 into the notch 25 on one side 
and a continuous grade ramp 28 on the other side. The cross-sections of 
notches 25 are oriented so that ramps 28 elevate in the same direction 
around the circumference of opening 22. 
As further shown by FIG. 5, identical roller wafer springs 29 and identical 
solid cylindrical rollers 30 are received uniformly into each notch 25 and 
are held captive therein by a single cylindrical roller cage 31. Best seen 
on FIG. 1, roller cage 31 contains identical rectangular holes 32 of a 
size and location to allow each roller 30 to protrude partially but 
uniformly through roller cage 31 when sitting fully within its respective 
notch 25. As shown on FIG. 3 and FIG. 4, roller cage 31 is then held in 
position by thrust washers 33 located within recesses 23 at each entrance 
to opening 22. Thrust washers 33 are in turn held in position by retainer 
snap rings 34 located over thrust washers 33 and within grooves 24 in 
recesses 23. 
The outside diameter of assembled socket 19 is chosen so that when received 
inside roller cage 31, as shown on FIG. 2, the outside cylindrical surface 
of socket 19 is in uniform close proximity to rollers 30, as shown on FIG. 
4 and FIG. 5. To operate the invention, socket pieces 18 are assembled to 
form socket 19 located over a fastener. Wrench head 11 is slipped over the 
assembly by receiving socket 19 into roller cage 31. FIG. 5 shows that as 
torque is applied about socket 19, rollers 30 begin to roll uniformly and 
synchronously out of notches 25 and up ramps 28. As rollers 30 continue to 
roll up ramps 28, the diametric pitch of rollers 30 constricts uniformly, 
causing rollers 30 to synchronously wedge tight between ramps 28 and the 
outside surface of socket 19. Once wedged tight, rollers 30 are then in 
friction with the outside surface of socket 19 and thereby impart torsion 
to socket 19. The forced diametric constriction of the circular pitch of 
rollers 30 also results in a uniform radial compression that clamps socket 
19 tighter over the fastener as torque to the wrench is increased. 
Releasing socket 19 is simply a matter of reversing the direction of 
rotation of handle 12. Referring again to FIG. 5, rollers 30 roll back 
down ramps 28 and into notches 25. Once back in notches 25, rollers 30 
then allow free reverse rotation until torque is again applied in the 
original direction to bring rollers 30 back up ramps 28. 
In order to reverse the direction of operation of the invention, assembled 
socket 19 is received into roller cage 31 from the opposite side of head 
11. Ramps 28 are then oriented to constrict the diametric pitch of rollers 
30 when torque is applied to handle 12 in the reverse direction. 
The invention has been shown, described and illustrated in substantial 
detail with reference to a presently preferred embodiment. However, it 
will be understood by those skilled in the art that changes and 
modifications may be made without departing from the spirit and scope of 
the invention which is defined by the claims set forth hereunder.