Adjustable gripping device

An adjustable gripping device (10) in the nature of an adjustable socket including a body (11) supporting a stem (14) having arcuate guide surfaces (16) along which gripping jaws (19) slide. The gripping jaws (19) include teeth (23) on their outer surfaces and a rotatable adjuster (24) is provided with an internal thread (27) for cooperation with the teeth (23) such that when the adjuster (24) is rotated in opposite directions, the jaws (19) move inwardly and outwardly.

TECHNICAL FIELD 
This invention relates to an adjustable gripping device which in a 
particular aspect is in the form of an adjustable socket. 
1. Background Art 
Socket sets are a common tool used for driving bolts and nuts. Usually such 
sockets sets comprise a plurality of sockets of different sizes to suit 
different sized nuts or bolts. Use of such sockets is often inconvenient 
where for example many different size nuts or bolts are encountered as 
different sockets are required to be individually detached from the 
driving tool or wrench and the correct sized socket reattached to suit the 
particular size nut or bolt to be driven. Inconvenience also often arises 
if a particular size socket is not readily available. 
Some adjustable sockets have been proposed in the past to overcome the 
above problem, however, the known adjustable have a number of 
disadvantages. For example such adjustable sockets are generally 
relatively complex with some involving springs to bias gripping jaws 
outwardly. The use of springs often causes difficulties in manufacture and 
use. Other adjustable sockets such as those disclosed in International 
Patent Application No. PCT/AU86/01319 have jaws with a limited range of 
opening so that their application is limited. Additionally most adjustable 
sockets have dimensions which make them unsuitable for use in confined 
spaces. 
2. Disclosure of the Invention 
The present invention aims to overcome or at least alleviate one or more of 
the above disadvantages by providing an adjustable gripping device which 
may be in the form of an adjustable socket which is of simple construction 
such as to lend itself to easy manufacture. The present invention in a 
preferred form aims to provide an adjustable gripping device which may be 
constructed so as to have relatively small overall dimensions whereby to 
enable it to be used in confined spaces. The present invention further 
preferably aims to provide an adjustable gripping device in which the 
range of jaw openings is relatively large so as to facilitate gripping of 
members of a range of different sizes. Other objects and advantages of the 
invention will become apparent from the following description. 
With the above and other objects in view the present invention provides in 
a first aspect an adjustable gripping device including a body adapted to 
be driven for rotation about a central axis, a plurality of jaws spaced 
about said central axis and supported for movement relative to said body 
and adjuster means mounted to said body and rotatable relative thereto 
about said central axis, said adjuster means co-operating with said jaws 
and adapted when rotated to move said jaws along an arcuate path 
longitudinally of said body and radially inwardly or outwardly relative to 
said central axis. 
The body preferably supports or includes a guide with which each jaw 
co-operates, each jaw being in bearing engagement with the guide. 
Preferably the jaws have an arcuate portion or shank and the guide has 
corresponding arcuate guide surfaces adapted to receive in a complementary 
manner, the respective arcuate portions or shanks of the jaws so that the 
jaws are guided along their arcuate path of movement. Preferably the guide 
and adjuster means define therebetween respective slots through which each 
jaw projects, each jaw moving inwardly and outwardly of its associated 
slot upon rotation of the adjuster means. The arcuate guide surfaces of 
the guide are separated by longitudinally extending ribs so that the jaws 
are constrained for longitudinal and radial movement as described. 
Preferably each jaw is provided with a plurality of teeth and the adjuster 
means is provided with an internal thread adapted to be engaged by the 
teeth on the jaws whereby the cooperation between the thread and teeth 
causes movement of the jaws both longitudinally and radially relative to 
the body upon rotation of the adjuster means. 
The thread on the adjuster means suitably has a pitch circle which 
increases in diameter longitudinally of the body so to be of generally 
bell shaped form to match the curvature of the guide and arcuate shank of 
the jaws. 
The adjuster means may be of tubular or sleeve like form or may have an 
external surface which flares outwardly longitudinally so as to have an 
increased thickness in the region of the thread. 
The present invention provides in a further preferred aspect an adjustable 
socket comprising supporting body means having a longitudinally extending 
axis, said body having a plurality of slideways spaced about said axis, 
said slideways being of arcuate form and extending longitudinally of said 
body means so as to flare outwardly, a plurality of jaws spaced about said 
central axis and supported for sliding movement along respective said 
slideways, said jaws having on their external surfaces teeth means, 
adjuster means rotatable relative to said body about said axis, said 
adjuster means having an internal thread for co-operation with said teeth 
means, said adjuster means being adapted to be rotated to cause through 
co-operation between said teeth means and said thread, movement of said 
jaws along said slideways and thus radially inwardly or outwardly relative 
to said central axis. 
In a further preferred aspect, the present invention provides an adjustable 
gripping device comprising guide means having a longitudinally extending 
axis, said guide means having a plurality of longitudinally extending 
slideways spaced about said axis, said slideways being of arcuate form, a 
plurality of jaw means spaced about said central axis, said jaw means 
having surfaces complementary to said slideways and being supported for 
sliding movement along respective said slideways, adjuster means disposed 
about said guide means and jaw means and being rotatable about said axis, 
said adjuster means having means cooperating with said jaw means and being 
adapted to be rotated to cause through said cooperation longitudinal 
movement of said jaw means along said slideways and thus radially inwardly 
or outwardly relative to said central axis.

DETAILED DESCRIPTION OF THE EMBODIMENTS 
Referring to the drawings and firstly to FIGS. 1 to 6 there is illustrated 
an adjustable gripping device 10 according to the present invention, 
including a body 11 having a central axis 12 and being provided at one end 
with a central square recess 13 adapted to be engaged by a correspondingly 
shaped tang of a driving tool or wrench. Secured to the body 11 or formed 
integrally therewith is a guide 14 which extends axially of the body 11 
along the axis 12. 
The guide 14 is, as apparent in FIG. 6 of generally triangular cross 
section at its end adjacent the body 11 to form a stem 15 which is 
connected to the body 11. At its opposite end the guide 14 defines three 
longitudinally extending arcuate slideways or slide surfaces 16. As is 
apparent, the slideways 16 are arranged about the axis 12 with adjacent 
slideways 16 disposed at an acute angle to each other and are separated 
from each other by longitudinally extending ribs 17, the ribs 17 at the 
free end of the guide 14 having outer arcuate surfaces centred on the axis 
12. Both the slideways 16 and ribs 17 flare outwardly towards the free end 
of the guide 14 so as to lie along arcs centred on, and at a radius R 
from, an axis 18 located outwardly of the slideways 16 and extending 
normal to the central axis 12 of the body 11 and guide 14. 
Adapted for co-operation with the guide 14 are three jaws 19, each of which 
includes at one end an arcuate shank 20 which has an inner surface 21 
complementary to the arcuate surfaces of the slideways 16. Each shank 20 
is adapted to seat within a respective slideway 16 so as to be slidable 
longitudinally of the slideway 16 whilst being in bearing contact 
therewith. Each jaw 19 also includes at its opposite free end a gripping 
portion 22 which is inclined to or extends at an obtuse angle to the shank 
20 so as to enable the jaws 19 to grip an object in all positions as 
described further below. As shown in FIG. 1, the portions are inclined 
inwardly towards each other in the closed position of the device 10. The 
shank 20 of each jaw 19 additionally includes on its outer side a 
plurality of teeth 23 which are spaced longitudinally along the shank 20 
and adapted for co-operation with an adjuster 24. 
The adjuster 24 is mounted to the body 11 and guide 14 for rotation about 
the central axis 12. The adjuster 24 is of somewhat tubular or sleeve-like 
form and includes at one end an annular ring 25 which locates within a 
correspondingly shaped annular groove 26 in the end of the body 11 whereby 
to allow for rotational movement of the adjuster 24 relative to the body 
11. At its opposite end, the adjuster 24 is internally helically threaded 
at 27, the thread 27 being formed with an increasing pitch diameter from 
its inner axial end to its outer axial end so as to be of bell shaped 
configuration to match the curvature of the slideways 16 and shanks 20. 
The teeth 23 of the respective shanks 20 are engaged by the helical thread 
27 to enable adjusting movement of the jaws 19 as described further below. 
As is apparent in FIGS. 1 and 3 the adjuster 24 cooperates with the ribs 
17 so as to close the open outer sides of the slideways 16 and define 
slots 28 through which the shanks 20 of the jaws 19 project. The jaw 
shanks 20 are thus constrained in use for movement along the slideways 16 
and between the respective ribs 17. 
Upon rotation of the adjuster 24 in opposite directions the co-operation 
between the thread 27 and teeth 23 on the adjuster 24 and the jaw shanks 
20, respectively will cause movement of the jaws 19 longitudinally of the 
central axis 12 of the device 10 between the position of FIG. 1 and that 
of FIG. 7. Additionally, as the shanks 20 are moved longitudinally of the 
body 11 and guide 14 the co-operation between the respective arcuate 
surfaces of the slideways 16 and the arcuate surfaces 21 of the jaw shanks 
20 will constrain the jaws to move radially inwardly and outwardly 
relative to the axis 12. 
Thus in the closed position of FIGS. 1 and 3, the jaw shanks 20 are fully 
retracted and the gripping portions 22 of the jaws 19 are disposed 
adjacent to each other to define the minimum gripping size say for 
gripping the hexagonal nut or bolt head 29 shown in dotted outline. In the 
fully extended position of the jaw shanks 20, the gripping portions 22 are 
opened to the position of FIGS. 7 and 8 so as to enable gripping of the 
hexagonal head 30 shown in dotted outline. It will thus be apparent that 
the described arrangement allows for a large degree of opening of the jaws 
19 so as to enable gripping of a large size range of bolts or nuts. 
The gripping device 10 of the present invention is particularly suited to 
use as a an adjustable socket for gripping hexagonal nuts or bolt heads. 
The device 10 of the invention however may have applications in gripping 
other objects such as square sectioned heads of nuts or bolts. In such a 
configuration, the device 10 may be provided with two opposite jaws or 
four or more jaws arranged about the axis 12 of the device 10. 
The gripping portion 22 of the jaws 19 may if desired by provided on their 
inner faces with a grip increasing surface finish for example a grooved 
finish to avoid slipping. In an alternative configuration the inner 
gripping faces of the gripping portions 22 may have a convex configuration 
in cross-section so as to engage an article to be gripped along the peak 
of the convex shape. The outer surface of the adjuster 24 may also 
suitably be knurled or provided with other surface finish to facilitate 
gripping and tightening by hand or include configurations to enable 
tightening by use of a separate tool. The adjuster 24 may also be of 
outwardly flared form to increase the thickness of the wall about the 
thread 27 and provide for convenient gripping. Whilst the body 11 of the 
device 10 is described as having a female square recess 13, it may be 
provided with a recess of other configurations to suit a driving tool or 
wrench. Alternatively, the body 11 may be provided with a male 
configuration such as hexagonal flats on its outer surface or a hexagonal 
stem to facilitate gripping by a suitable tool. In yet an alternative 
configuration, the body 11 may be formed integrally with or connected, say 
through a universal joint, to a wrench or lever arm. 
In yet an alternative configuration, the teeth 23 on the jaws 19 may be 
eliminated as may the threads 27 on the adjuster 24. Longitudinal movement 
of the jaws 19 may then be achieved by other activating means which for 
example may engage or be coupled to the rear ends of the jaws 19 to cause 
longitudinal movement thereof. Such means may include a threaded member 
whose rotational movement in opposite directions causes longitudinal 
movement of the jaws 19. The jaws 16 in this configuration would still of 
course move along an arcuate path as described above. 
The device 10 of the invention may also be motor actuated or driven. For 
example the body 11 may be coupled to a power driven tool or the adjuster 
24 may be driven rotatably in opposite directions by a drive motor or 
drive means of any form for gripping an article for use say in 
manufacturing operations. Additionally, in some configurations, the body 
11 in the form described may be eliminated and the guide 14 secured to or 
comprised in an alternative form of tool. 
Whilst the above has been given by way of illustrative embodiment of the 
invention, all such modifications and variations thereto as would be 
apparent to persons skilled in the art are deemed to fall within the broad 
scope and ambit of the invention as herein set forth.