Quick release mechanism for tools such as socket wrenches

A tool of the type having a drive stud for receiving and releasing a tool attachment includes an opening in the drive stud and a locking pin movably mounted in the opening. The opening defines upper and lower ends, and the lower end of the opening is located at a portion of the drive stud constructed for insertion into the tool attachment. The lower end of the locking pin is constructed to engage the tool attachment when the locking pin is positioned in an engaging position and to release the tool attachment when the locking pin is moved to a release position. An actuating element is movably positioned on the drive stud, and the actuating element is coupled to the locking pin to move the locking pin from the engaging to the release position as the actuating element moves along the longitudinal axis. An anti-rotation key is positioned between the actuating element and the drive stud to slide in a groove formed in either the actuating element or the drive stud and thereby to limit rotation of the actuating element and associated side loading of the locking pin. If desired, a resilient retaining element can be positioned in a recess in either the actuating element or the drive stud to limit movement of the actuating element relative to the drive stud along the longitudinal axis.

BACKGROUND OF THE INVENTION 
This invention relates to torque transmitting tools of the type having a 
drive stud shaped to receive and release a tool attachment, and in 
particular to an improved quick release mechanism for securing and 
releasing a tool attachment to and releasing it from the drive stud. 
My previous U.S. Pat. No. 4,848,196 discloses several quick release 
mechanisms for securing tool attachments such as sockets to torque 
transmitting tools such as wrenches. In these mechanisms the tool includes 
a drive stud which defines a diagonally oriented opening, and a locking 
pin positioned within the opening so as to move in the opening. In its 
engaging position, the lower end of the locking pin engages a recess in 
the socket so as to lock the socket positively in place on the drive stud. 
When the operator moves the pin in the opening, the lower end of the pin 
is moved out of contact with the socket, and the socket is released from 
the drive stud. 
In the mechanism shown in FIGS. 1 through 5 of U.S. Pat. No. 4,848,196, the 
locking pin is held in place by an extension spring which surrounds the 
shaft of the drive stud. In the version shown in FIGS. 6 and 7, the 
extension spring is covered by a protective sleeve 70 with flanges 74, 76. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide an improved quick release 
mechanism which is simple in construction; which requires only a few, 
easily manufactured parts; which is rugged and reliable in use; which 
automatically accommodates various sockets, including those with and 
without recesses designed to receive a detent; which substantially 
eliminates any precise alignment requirements; which is readily cleaned; 
which presents a minimum of snagging surfaces; which is low in profile; 
which restrains the actuating element against rotation, and which protects 
the locking element from side loading. 
This invention represents an improvement in a tool of the type comprising a 
drive stud for receiving and releasing a tool attachment; wherein the 
drive stud has an opening therein; wherein a locking element is movably 
disposed in the opening; wherein the drive stud defines a longitudinal 
axis and the opening is oriented at a first non-zero skew angle with 
respect to the longitudinal axis; wherein the opening defines upper and 
lower ends, the lower end of the opening being located at a portion of the 
drive stud constructed for insertion into the tool attachment; and wherein 
the lower end of the locking element is constructed to engage the tool 
attachment when the locking element is positioned in an engaging position 
and to release the tool attachment from the drive stud when the locking 
element is moved to a release position. 
According to this invention, an actuating element is slidably positioned on 
the drive stud to move along the longitudinal axis. Actuating the 
actuating element moves the locking element from the engaging position to 
the release position as the actuating element moves along the longitudinal 
axis, and rotation of the actuating element would normally apply side 
loads to the locking element, unless rotation were prevented. An 
anti-rotation element is coupled to one of the actuating element and the 
drive stud to slide along an out-of-round surface defined by the other of 
the actuating element and the drive stud. This out-of-round surface is 
oriented to prevent rotation of the actuating element about the 
longitudinal axis, and thereby to limit side loading of the locking 
element. 
In some embodiments, a resilient retaining member is positioned in a recess 
in either the actuating element or the drive stud to engage the other of 
the actuating element and the drive stud to limit movement of the 
actuating element relative to the drive stud along the longitudinal axis. 
The preferred embodiments described below are unusually simple, compact, 
rugged and inexpensive to manufacture.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
Turning now to the drawings, FIG. 1 shows a side elevational view of a tool 
which in this preferred embodiment is an extension bar E. As shown in FIG. 
1, extension bar E is designed to be mounted on a wrench W and to fit into 
and transmit torque to a socket S. The extension bar E terminates at its 
lower end in a drive stud 10 having a lower portion 12 and an upper 
portion 14. The lower portion 12 is constructed for insertion into the 
socket S, and defines an out-of-round cross section. Typically, the lower 
portion 12 has a square, hexagonal or other non-circular shape in 
horizontal cross section. The upper portion 14 will often define a 
circular cross section, though this is not required. 
As shown in FIG. 1, the drive stud 10 is configured to define a diagonally 
positioned opening 16 having a lower end 18 and a upper end 20. The lower 
end 18 is positioned in the lower portion 12 of the drive stud 10, and the 
upper end 20 is positioned in the upper portion 14 of the drive stud 10. 
The opening 16 has a smaller diameter adjacent the upper end 20 than the 
lower end 18, and the opening 16 defines a transverse step 22 between the 
larger and smaller diameter portions of the opening 16. 
The foregoing features of the wrench W, extension bar E and socket S are 
substantially as described in connection with FIGS. 20-25 of U.S. Pat. No. 
4,848,196. It may be preferable in some embodiments to provide the opening 
16 with a constant diameter, and to define the step 22 in some other 
manner, as for example with a plug of the type shown in FIG. 20 of my 
previous U.S. Pat. No. 4,848,196. 
As shown in FIG. 1, a locking element such as a pin 24 is slidably 
positioned in the opening 16. This pin 24 defines a lower end 26 shaped to 
engage the socket S. The lower end 26 of the pin 24 may be conventionally 
rounded, or it may alternately be provided with a step as shown in U.S. 
Pat. No. 4,848,196 or other useful shapes. Though illustrated as a pin 24, 
the locking element may take various shapes, including irregular and 
elongated shapes. The purpose of the locking element is to hold the tool 
attachment in place on the drive stud during normal use, for example when 
pulled by a user, and the term "locking" does not imply locking the tool 
attachment in place against all conceivable forces tending to dislodge the 
tool attachment. If desired, the pin 24 may be provided with an out of 
round cross section and the opening 16 may define a complementary shape 
such that a preferred rotational position of the pin 24 in the opening 16 
is automatically obtained. The pin 24 defines a reduced diameter neck 27 
that terminates at one end at a step 28 and at the other at an enlarged 
head 30. The underside of the head 30 defines a ledge surface 32 oriented 
transversely to the length of the pin 24. The ledge surface 32 may be 
flat, convex, concave or spherical. Similarly, other shapes for the ledge 
surface 32 are possible so as to allow the ledge surface 32 and sliding 
surface 38 to cooperate with each other so as to move relative to each 
other without binding. Furthermore, the ledge surface 32 may be 
discontinuous or have a plurality of surfaces. 
Also as shown in FIG. 1, an actuating element such as a collar 34 is 
positioned around the upper portion 14 of the drive stud 10. This collar 
34 defines a slot 36 and an adjacent sliding surface 38, as best shown in 
FIG. 2. 
As best shown in FIG. 1, the drive stud 10 defines a longitudinal axis 40, 
and the collar 34 is guided to move along the longitudinal axis 40. The 
opening 16 defines an opening axis 44 which is oriented at a first 
non-zero acute angle .alpha.1 with respect to the longitudinal axis 40. 
The sliding surface 38 is oriented at a second non-zero skew angle 
.alpha.2 with respect to the longitudinal axis. The angles .alpha.1 and 
.alpha.2 preferably differ by 90.degree.. With this arrangement, the 
sliding surface 38 is oriented parallel to the ledge surface 32 and 
transverse to the pin 24. In other embodiments, the sliding surface 38 may 
have other shapes, such as a discontinuous surface or a plurality of 
surfaces, to allow relative movement between sliding surface 38 and ledge 
surface 32 without binding. Thus, it is contemplated to employ all 
combinations of shapes for ledge surface 32 and sliding surface 38 which 
allow them to cooperate with each other so as to move relative to each 
other without binding. 
A spring such as a coil spring 42 biases the pin 24 to the engaging 
position shown in FIG. 1. As shown, the spring 42 is an extension spring 
which bears between the step 22 and the step 28 in the locking pin 24, 
with the neck 27 passing through the spring 42. In alternate embodiments 
the spring may be implemented in other forms, as for example by means of a 
leaf spring. Furthermore, if a coil spring is used, it may be employed as 
either a compression or an extension spring with suitable alterations to 
the design of FIG. 1, and the spring may be eliminated in some 
embodiments. In some embodiments the step 22 is not required. 
As best shown in the enlarged view of FIG. 3, the drive stud 10 defines a 
longitudinally extending groove 48 and a circumferentially extending 
recess 50. The collar 34 defines a longitudinally extending groove 52 
which generally corresponds in position and dimension to the groove 48. 
Both the grooves 48 and 52 are generally rectangular in cross section, and 
are bounded by faces 49, 53 respectively. Of course, the grooves 48, 52 
may be provided with any suitable cross sectional shapes. 
An anti-rotation element such as a key 54 is fixed in the groove 48 by a 
resilient retaining element such as a C-shaped spring clip 56. The key 54 
is immobilized in the circumferential direction by the faces 49 defined by 
the groove 48 in the drive stud 10. The key 54 is sized to provide a 
sliding fit in the groove 48, and the spring clip 56 engages the recess 50 
to prevent the key 54 from moving longitudinally out of the groove 48. The 
collar 34 prevents the key 54 from moving radially outwardly out of the 
groove 48, and the faces 53 cooperate with the key 54 to prevent the 
collar 34 from rotating relative to the drive stud 10. As illustrated, the 
collar 34 and the locking pin 24 are coupled together in such a way that 
rotation of the collar 34 tends to side load the locking pin 24. By 
preventing rotation of the collar 34, the key 54 protects the locking pin 
24 and the locking neck 27 from damage due to such side loading. As shown 
in FIG. 4, the key 54 accommodates longitudinal movement of the collar 34 
in the longitudinal direction of the arrows of FIG. 4, because the groove 
52 of the collar 34 is aligned with the longitudinal direction, and the 
key 54 provides a sliding fit in the groove 52. 
The pin 24, the collar 34 and the spring 42 can be assembled in a 
straightforward manner on the drive stud 10. First the spring 42 is placed 
around the neck 27 of the pin 24, and this assembly is then placed in the 
opening 16 via the lower end 18. The pin 24 is then moved to compress the 
spring 42 between the step 28 on the pin 24 and the step 22 in the opening 
16 until the head 30 protrudes out of the opening 16. Then the collar 34 
is moved past the lower portion 12 onto the upper portion 14 of the drive 
stud 10, with the neck 27 passing through the slot 36, and with the ledge 
surface 32 sliding on the sliding surface 38. Once the collar 34 is 
properly seated, the key 54 is moved longitudinally in the groove 48 to 
the position shown in FIG. 4, and the spring clip 56 is installed in the 
recess 50. This completes assembly of the embodiment shown in FIGS. 1-4. 
Note that the spring clip 56 retains the key 54 in the groove 48, and by 
this action prevents both the key 54 and therefore the collar 34 from 
inadvertent disassembly. 
It is not essential in all embodiments that the spring clip 56 and the key 
54 be formed as separate elements. If desired, the spring clip 56 can be 
secured to the key 54, and they can even be formed of one piece as an 
integral unit. FIG. 5 shows a perspective view of a one-piece element 58 
that includes a key portion 60 that functions as an anti-rotation element 
and a spring clip portion 62 that functions as a retaining element. In 
this embodiment the spring clip portion 62 has a rectangular section and 
is intended for use with a rectangular groove (not shown) in the drive 
stud. 
The pin 24 simultaneously serves a number of separate functions. First, it 
releasably secures the socket S to the drive stud 10 as described below. 
Second, the pin 24 engages the slot 36 and thereby limits movement of the 
collar 34 away from the lower portion 12 of the drive stud 10. The pin 24 
captures the collar 34 positively in place, and the key 54 prevents any 
undesired rotation of the collar 34 and associated side loading of the pin 
24. 
Though the actuating element is shown as a collar 34 that slides along the 
longitudinal axis 40, an alternate embodiment of the actuating element may 
be formed as a slide that does not encircle the drive stud 10. 
FIGS. 6 and 7 provide longitudinal sectional views of a third preferred 
embodiment of this invention, corresponding to FIGS. 3 and 4, 
respectively. In this third embodiment similar elements to those discussed 
above in conjunction with FIGS. 1 through 4 are provided with the same 
reference numeral, with an added prime. 
As shown in FIG. 6, the drive stud 10' defines a groove 48' that is bounded 
by faces 49'. The drive stud 10' also defines a circumferential recess 50' 
that receives a retaining element or a spring clip 56' All of these 
features are identical to the corresponding features in the embodiment of 
FIGS. 3 and 4. 
In contrast to the embodiment of FIGS. 3 and 4, the collar 34' is rigidly 
secured to an anti-rotation element or key 54'. In the examples shown in 
FIGS. 6 and 7, the key 54' is received in a complementary opening 57' in 
the collar 34', such that there is no relative movement allowed between 
the key 54' and the collar 34'. The key 54' can be of any desired shape, 
and it can be formed integrally with the collar 34'. 
In this embodiment the spring clip 56' is retained in the recess 50' to 
prevent the collar 34' from moving excessively toward the locking pin 24'. 
The collar 34' rigidly secures the key 54' in place, and the key 54' fits 
in a sliding fit in the groove 48'. The key 54' cooperates with the faces 
49' to prevent relative rotation of the collar 34' with respect to the 
drive stud 10'. In this way the locking pin 24' is protected from 
excessive side loading. Because the spring clip 56' plays no role in 
retaining the key 54' in the groove 48', it is not important that the 
spring clip 56' cross the groove 48'. A spring clip which extends over a 
circumferential arc of 270.degree. or less can therefore be used. 
FIG. 8 shows a fourth preferred embodiment, which differs principally from 
the third embodiment of FIGS. 6 and 7 in two respects. First, the key 54" 
is formed in one piece with the collar 34". Second, the spring clip 56' 
and recess 50' of FIGS. 6 and 7 have been deleted. Instead, longitudinal 
movement of the collar 34" to the left as shown in FIG. 8 is limited by an 
upset 57". The upset 57" acts as a retaining element. The term 
"protrusion" will be used in a broad sense in connection with elements for 
retaining the collar on the drive stud; this term is intended to encompass 
deformations such as the upset 57", retaining elements such as the spring 
clip 56, as well as other suitable structures. 
The embodiment of FIG. 8 can be assembled in a manner similar to that 
described above, but there are of course fewer parts to assemble in the 
embodiment of FIG. 8. The upset 57" can be formed by deforming the drive 
stud 10" with an impact after the parts have been assembled as shown in 
FIG. 8. 
FIGS. 9-11 relate to a fifth preferred embodiment. In this fifth embodiment 
similar elements to those discussed above in conjunction with FIGS. 1-4 
are provided with the same reference numeral, with an added triple prime. 
As shown in FIGS. 10 and 11, the drive stud 10'" defines opposed planar 
faces or flats 60'" which extend to into the collar 34'". The drive stud 
10'" defines a circular cross-section in the region 64", and the reference 
numeral 62'" indicates the transition between the planar faces 60'" and 
the circular cross-section 64'". The planar faces 60'" are out-of-round 
surfaces extending longitudinally along the drive stud 10'" and providing 
an anti-rotation function as described below. In many ways, the planar 
faces 60'" perform the function of the grooves 48 discussed above. 
The collar 34'" defines a central opening which is circular in 
cross-section in the region 62'" so as to slide over the circular 
cross-section 64'" of the drive stud 10'". The collar 34'" also defines 
two protrusions 68'" which are best shown in FIGS. 10 and 11. These 
protrusions 68'" define planar inwardly directed surfaces which are 
complimentarily shaped to the planar faces 60'", as shown in FIG. 11. The 
protrusions 68'" are also out-of-round, and they are shaped to slide along 
the planar faces 60'". 
Because both the protrusions 68'" and the planar faces 60'" are 
out-of-round, they perform an anti-rotation function, preventing the 
collar 34'" from rotating on the drive stud 10", and thereby protecting 
the pin 24'" from side loading as discussed above. 
The embodiment of FIGS. 9-11 includes two planar faces 60'" and two 
protrusions 68'" oriented at 90.degree. with respect to the plane of FIG. 
9. It will, of course, be understood that a smaller or larger number of 
planar faces 60'" and mating protrusions 68'" can be used, and that they 
can be disposed at any desired angle with respect to the plane of FIG. 9. 
The embodiment of FIGS. 9-11 requires a reduced number of parts as compared 
with certain other embodiments of the invention, and this may provide a 
cost saving. Additionally, the embodiment of FIGS. 9-11 may require fewer 
fabrication operations such as machining, as well as fewer high precision 
fabrication operations. This embodiment is particularly robust and easy to 
assemble. Since the planar faces 60'" extend to the end of the drive stud 
10'", the collar 34'" can simply be inserted in place and then retained on 
the drive stud 10'" with the spring clip 56'". 
The operation of the quick release mechanisms described above will be 
apparent from FIGS. 1 through 11. The following comments focus on the 
embodiment of FIGS. 1-4. It will of course be understood that the other 
embodiments operate similarly, with the exceptions noted above. As shown 
in FIG. 1, when the lower portion 12 of the drive stud 10 is brought into 
alignment with the socket S, the lower end 26 of the locking pin 24 bears 
on the socket S. 
Further downward movement of the drive stud 10 moves the pin 24 inwardly in 
the opening 16, thereby allowing the lower portion 12 to move within the 
socket S. This can be done without manipulating the collar 34 in any way. 
When the drive stud 10 is fully seated in the socket S, the spring 42 
returns the locking pin 24 to the engaging position of FIG. 3, in which 
the lower end 26 of the locking pin 24 engages the recess R in the socket 
S. The pin 24 will provide at least frictional engagement, even with a 
socket S which does not include a recess R. 
Downward forces on the socket S are not effective to move the locking pin 
24 out of its engaging position, and the socket S is positively held in 
place on the drive stud 10. 
As shown in FIG. 4, the collar 34 is raised to release the socket S. This 
causes the sliding surface 38 to translate under the ledge surface 32, 
thereby applying a withdrawing force substantially aligned with the length 
of the opening 16. This withdrawing force is effective to compress the 
spring 42 and to move the pin 24 from the engaging position of FIG. 3 to 
the release position of FIG. 4. When the locking pin 24 reaches the 
release position the socket S is free to fall from the drive stud 10 under 
the force of gravity. 
This invention can be adapted for use with the widest range of torque 
transmitting tools, including hand tools, power tools and impact tools. 
Simply by way of illustration, this invention can be used with socket 
wrenches, including those having ratchets, T-bar wrenches, and speeder 
wrenches, all as described and shown in U.S. Pat. No. 4,848,196. 
Furthermore, this invention is not limited to sockets of the type shown, 
but can be used with a wide range of tool attachments, including sockets 
or tool attachments with varying sized recesses R and even on sockets 
without a recess of any type. 
Of course, this invention can be adapted for use with a wide variety of 
quick release mechanisms of the type defined in the preamble of claim 1. 
For example, this invention can readily be used with the quick release 
mechanisms shown in U.S. Pat. No. 4,848,196, and with the mechanism shown 
in U.S. patent application Ser. No. 07/959,215, which includes a tension 
member that interconnects the locking element and the actuating element. 
Of course, the quick release mechanism of this invention can be used in any 
physical orientation, and the terms "upper", "lower" and the like have 
been used with reference to the orientation shown in the drawings. 
Furthermore, the terms "engaging position" and "release position" are each 
intended to encompass multiple positions within a selected range. For 
example, in the embodiment of FIG. 1 the exact position of the engaging 
position will vary with the depth of the recess R in the socket S, and the 
exact position of the release position may vary with a variety of factors, 
including the extent to which the actuating element is moved. 
As suggested above, the present invention can be implemented in many ways, 
and this invention is not limited to the specific embodiments shown in the 
drawings. However, in order to define the presently preferred embodiment 
of this invention the following presently preferred details of 
construction are provided. These details are of course in no way intended 
to limit the scope of this invention. 
By way of example, the pin 24 may be formed of a material such as a steel 
of moderate to mild temper, and the collar 34 may be formed of any 
suitable material such as brass, steel, or powdered metal. The angle 
.alpha.1 may range from about 30.degree. to about 45.degree. and the angle 
.alpha.2 may range from about 120.degree. to about 135.degree., 
respectively. For a three-eighths drive wrench, the width of the sliding 
surface 38 may be about 0.15 inch or even larger, as long as it receives 
the head of the pin properly; the width of the slot 36 may be about 0.06 
inch; the length of the collar 34 may be about 0.49 inch; and the outer 
diameter of the collar 34 may be about 0.73 inch. 
From the foregoing description it should be apparent that the objects set 
out initially above have been achieved. In particular, the mechanism shown 
in the drawings is low profile with respect to the circumference of the 
extension bar E. The disclosed mechanism is simple to manufacture and 
assemble, and it requires relatively few parts. It is rugged in operation, 
and it automatically engages a socket as described above. Because of its 
design, the mechanism will accommodate various types of sockets, including 
sockets with various types of recesses or no recess at all. In the 
illustrated embodiment, the collar 34 may be gripped at any point on its 
circumference, and does not require the operator to use a preferred 
angular orientation of the tool. Furthermore, the outer circumference of 
the collar 34 may be shaped as shown in FIG. 2 to allow convenient 
manipulation of collar 34. The collar 34, 34', 34" is prevented from 
rotating relative to the drive stud 10, 10', 10", 10'" by the key 54, 54', 
54" and the protrusions 68", respectively. 
In the illustrated embodiment of FIG. 1, the sliding surface 38 is 
relatively narrow and confined to a region in the vicinity of the slot 36. 
Alternately, the sliding surface 38 may be extended laterally, resulting 
in a crescent shape at the end of the collar 34. Additionally, the slot 36 
may extend only partly through the thickness of the collar 34 so that 
neither the slot 36 nor the pin 24 extends through the outer cylindrical 
surface of the collar 34. In another embodiment the head 30 only extends 
through the thickness of the collar 34 when the pin 24 is fully withdrawn 
from its socket holding position. In some alternate embodiments, the 
locking element may be configured to require a positive action on the part 
of the operator to retract the locking element as the drive stud is moved 
into the socket. Certain of these embodiments may require recesses in the 
sockets as described above to provide all of the functional advantages 
described. 
In the preferred embodiment of FIG. 1, the difference between the first and 
second angles .alpha.1 and .alpha.2 is approximately 90.degree.. This 
minimizes skew forces applied to the pin 24 and minimizes any tendency of 
the pin 24 to bind in the opening 16. However, if friction between the pin 
24 and the walls of the opening 16 is sufficiently low, the sliding 
surface 38 may be positioned at a skew angle with respect to the pin 24 
rather than the transverse angle illustrated. 
It is intended that the foregoing detailed description be regarded as 
illustrative rather than limiting, and that it be understood that it is 
the following claims, including all equivalents, which are intended to 
define the scope of this invention.