Socket assembly for multiple size wrenching surfaces

A socket assembly adapts automatically to wrenching surfaces of a nut or a bolt within a predetermined range of sizes. The socket assembly includes interfitting and relatively rotatable outer and inner annular members and a plurality of spring-loaded pawls for gripping the wrenching surfaces of the nut or the bolt to impart wrenching torque thereto.

BACKGROUND OF THE INVENTION 
This invention relates to wrenching devices and more particularly to a 
socket assembly which can accommodate a range of wrenching surface sizes 
so as to reduce the number of sockets necessary to handle a total range of 
wrenching surface sizes. 
Turner U.S. Pat. No. 1,033,358 which issued July 23, 1912 utilizes 
different sets of sectional head members which may be placed in different 
slots of a wrench to operate on different size nuts. The wrenching head 
members are readily interchanged with other items, such as taps. 
Sayre U.S. Pat. No. 1,058,795 which issued Apr. 15, 1913 presents a 
ratchet-wrench with a removable member adapted to be associated with the 
head of the wrench whereby the wrench may be applied to nuts of various 
sizes. 
Pearson U.S. Pat. No. 1,997,948 which issued Apr. 16, 1935 teaches a socket 
wrench which automatically adapts itself to nuts and bolt heads of 
different sizes. This is accomplished by means of spring loaded nested 
sockets of different sizes. 
Hurst et al. U.S. Pat. No. 4,528,875 which issued July 16, 1985 discloses 
an adjustable socket having telescoping wrenching shims. A lever controls 
the number of shims which are permitted to move. 
Tien U.S. Pat. No. 4,646,594 which issued Mar. 3, 1987 teaches a wrench 
socket for square and hexagonal wrenching surfaces. The socket is closed 
and is defined by eight right angled notches for reception of a driving 
head. The notches have a square opening of four notches equally spaced and 
sized to engage the square nut or bolt, and a hexagonal opening of six 
notches for engagement with a hexagonal wrenching surface. 
Kelly et al. U.S. Pat. No. 4,699,029 which issued Oct. 13, 1987 discloses a 
wrench socket having an end to receive a driving wrench in an internal 
drive opening, a driving end for engaging a threaded fastener to transmit 
a driving torque and an intermediate external surface area which can be 
engaged by a second driving wrench. A removable retainer assures that the 
second wrench is held on the socket, and a series of sockets may be 
provided which have various sized driving ends. 
The present invention distinguishes over the prior patents mentioned above. 
It is an important object of the present invention to provide a socket 
assembly which automatically accommodates itself in use to wrenching 
surfaces of a plurality of sizes. 
It is another important object of the invention to provide a set of such 
socket assemblies of varying sizes such that the number of sockets needed 
to handle a total range of wrenching surface sizes is reduced with respect 
to the prior art. 
It is a further object of the invention to provide such a socket which can 
be used on either hexagonal or square wrenching surfaces. 
It is yet another object of the invention to provide such a socket which 
can be used on wrenching surfaces dimensioned in any system such as Metric 
or English. 
It is a still further important object of the invention to provide such a 
socket assembly which is of economical construction. 
It is still another object of the invention to provide such a socket 
assembly which is reliable in operation. 
The above and other objects and advantages will become evident hereinafter. 
SUMMARY OF THE INVENTION 
A socket assembly embodying the invention adapts automatically to wrenching 
surfaces of a nut or a bolt within a predetermined range of sizes. The 
members of a set of such socket assemblies are of different sizes for 
imparting wrenching torque to wrenching surfaces having dimensions within 
a plurality of size ranges. 
More specifically, a preferred socket assembly embodying the invention 
comprises an outer annular member adapted for releasable engagement by a 
wrench and having an internal annular wall having a pair of like 
cylindrical portions defining an axis of the assembly and a pair of 
identical diametrically opposite inwardly extending lobed cam surfaces 
joining the cylindrical portions. 
The socket assembly also comprises an inner annular member within the wall 
of the outer annular member and having a pair of diametrically opposite 
slots open at one end of the inner member, first and second identical 
pawls each having an inner face with a jaw portion and an outwardly bulged 
lobed portion opposite the inner face. The pawls are mounted with the 
inner faces confronting each other and the bulged lobed portions extending 
outwardly through the slots in the inner member. Means in the form of wire 
springs urge the bulged lobed portions outwardly against the lobed cam 
surfaces, so that with the wrenching surfaces of the nut or bolt within 
the inner member, relative rotation of the members in one direction will 
cause the cam surfaces to push the jaw portions inwardly against the 
wrenching surfaces and the outer and inner members will thereupon rotate 
together as a unit to apply wrenching torque to the wrenching surfaces.

DESCRIPTION OF THE INVENTION 
FIGS. 1, 3 and 4 show a preferred socket assembly 10 according to the 
invention. Assembly 10 comprises an outer annular member 12 having a base 
portion 14 with a floor 16 and an internal annular wall 18 upstanding from 
floor 16 and having cylindrical portions 19 defining an axis. Wall 18 
terminates at an upper open end 20 and has an internal circumferential 
groove 22 just below end 20. Wall 18 also has a pair of diametrically 
opposite inwardly extending lobed cam surfaces 24 interrupting cylindrical 
wall portions 19. Cam surfaces 24 are identical and each has a clockwise 
facing component and a counterclockwise facing component. The clockwise 
and counterclockwise facing components are mirror images of each other and 
the junctures of the clockwise and counterclockwise facing components 
provide member 12 with a location of minimum internal transverse 
dimension. Finally, member 12 has a bottom end 26 parallel to floor 16 and 
containing an internal wrenching surface 28 shown about to be removably 
engaged by an external wrenching surface 30 of a wrench 32 which is shown 
in phantom in FIG. 4. To achieve such engagement, wrench 32 is moved in 
the direction of the arrow in FIG. 4 to insert wrenching surface 30 into 
wrenching surface 28 in known fashion. 
Assembly 10 further comprises an inner annular member 34 having an outer 
cylindrical surface 36 defining an axis of member 34. Surface 36 is 
preferably but not necessarily of a diameter slightly less than the 
minimum internal transverse dimension of outer member 12, which, as 
aforesaid, is provided by the junctures of the clockwise and 
counterclockwise facing components of lobed cam surfaces 24. Inner member 
34 has a central hole 38 at one end which also has an inturned base flange 
40. Inner member 34 further has an end 42 opposite hole 38. A pair of like 
diametrically opposite parallel-sided slots 44 open at end 42. Slots 44 
extend from end 42 substantially all the way to internal flange 40. 
Base flange 40 is provided with a pair of diametrically spaced tapped holes 
46 (FIGS. 1 and 4) parallel to the axis of inner member 34. 
Socket assembly 10 further comprises a pair of like bolts 48 each having a 
head 50, a shank 52 and external threads 54 on shank 52 at the end thereof 
remote from head 50. Threads 54 mate with tapped holes 46 such that bolts 
48 are capable of being turned into screw threaded engagement with holes 
46. 
Additionally, socket assembly 10 includes four like pawls 56 each being of 
more or less arcuate configuration, having a concave portion 58 and a 
serrated jaw portion 60 on its inner face and an outwardly bulged lobed 
portion 62 opposite concave portion 58. Each pawl 56 further has a 
mounting hole 64. Two pawls 56 are mounted on each bolt 48 with the shank 
52 thereof passing through holes 64 and threads 54 of bolts 48 are brought 
into threaded engagement with tapped holes 46 and with outwardly bulged 
lobed portions 62 of pawls 56 located in slots 44. A spacer 63 is located 
directly under head 50 of each bolt 48, and each pawl 56 has a wire spring 
member 65 associated therewith resiliently urging jaw portion 60 outwardly 
away from the axis of annular member 34 in known fashion. Also, four 
sleeves 67 fit over shanks 52 for locating pawls 56 at the desired 
locations on bolts 48. 
The two pawls 56 assembled with each bolt 48 include a lower pawl 56 and an 
upper pawl 56. The two lower pawls 56 are in registry with each other and 
the two upper pawls 56 are in registry with each other. 
The assembly of inner annular member 34, bolts 48 and pawls 56 is a 
sub-assembly of socket assembly 10 and is assembled with outer annular 
member 12 within annular wall 18 and is retained therein by a split ring 
66 which is commonly available as a Truarc.TM. ring which is placed in 
groove 22 of outer annular member 12. 
Outwardly bulged lobed portions 62 of pawls 56 are engaged by internal wall 
18, more particularly by lobed cam surfaces 24. 
Relative rotation of outer annular member 12 with respect to inner annular 
member 34 will cause the counterclockwise facing components of cam 
surfaces 24 to move serrated jaw portions 60 of pawls 56 toward the axis 
of socket assembly 10, against the bias of springs 65. 
More particularly, when a fastening device, such as a nut 70, having an 
across-the-flats dimension in the particular range adapted to be handled 
automatically by socket assembly 10 is placed in inner annular member 34 
with opposite wrenching surfaces in engagement with serrated jaw portions 
60 of one or both pairs of pawls 56 and with nut 70 in threaded engagement 
with an external thread 72 of a bolt 74, rotation of outer annular member 
12 in the direction of arrow A in FIG. 3 will cause the counterclockwise 
facing components of cam surfaces 24 to push serrated jaw portions 60 of 
pawls 56 against the wrenching surfaces of nut 70 to effect wrenching 
rotation thereof in an advancing direction (if the threads are righthand 
threads). 
Upon completion of the wrenching operation, which may involve applying 
socket assembly 10 to a bolt head instead of to a nut, assembly 10 is 
removed from the wrenching surfaces. 
To perform a loosening operation, socket assembly 10 is manipulated so that 
bulged lobed portions 62 of pawls 56 engage the clockwise facing 
components of cam surfaces 24 instead of the counterclockwise facing 
components thereof, socket assembly 10 is applied to the external 
wrenching surfaces and clockwise torque is applied. This will cause 
loosening rotation of the fastening device in a fashion similar to the 
tightening operation described above. 
A socket assembly 10 of: a first size can handle an across-the-flats 
wrenching dimension in the range from 0.125 inch to 0.375 inch; a second 
size can handle such a range from 0.375 inch to 0.75 inch; and a third 
size can handle such a range from 0.75 inch to 1.125 inches. Thus, the 
invention reduces from about sixteen or twenty to three the number of 
sockets or socket assemblies needed to cover the wrenching size range from 
0.125 inch to 1.125 inches. Furthermore, the wrenching surfaces can be 
hexagonal or square and the distance across the flats can be expressed in 
British or Metric units. 
FIG. 5 shows in axial section a modified preferred socket assembly 100 
embodying the invention. Socket assembly 100 is particularly suitable for 
use with an automatic lug wrench 320 having an internal wrenching surface 
300. Socket assembly 100 has an outer annular member 120 having a base 
portion 140 with an external wrenching surface 280 adapted for wrenching 
engagement with internal wrenching surface 300 of lug wrench 320. Socket 
assembly 100 is otherwise like socket assembly 10 except that socket 
assembly 100 has only one pawl 560, one wire spring member 650 and one 
spacer 67 associated with each bolt 48. Pawls 560 and spring members 650 
are of increased axial length compared with pawls 56 and spring members 
65. 
It is apparent that the invention achieves the above stated objects and 
advantages and others. 
The disclosed details are exemplary only and are not to be taken as 
limitations on the invention except as those details are included in the 
appended claims.