Jaw assembly

A jaw assembly for use with a lathe chuck which is rotatable about an axis and provided with at least two first cooperative mating portions circumferentially spaced apart about the axis. The jaw assembly includes at least two cylindrical bodies. Each body has a longitudinal axis, a cylindrical outer surface and first and second spaced-apart generally parallel outer planar surfaces disposed in planes generally perpendicular to the longitudinal axis and to the cylindrical outer surface. Each body is adapted to have at least three circumferentially spaced-apart workpiece-receiving cutouts therein extending through at least the outer cylindrical surface and the first planar surface. Each body carries second cooperative mating portions for mating with the first cooperative mating portions of the chuck to secure the body to the chuck so that the body rotates in an immovable manner with respect to the chuck. The bodies are mountable with respect to the chuck to rotate therewith in at least three different positions.

This invention pertains generally to jaw assemblies for use on lathe chucks 
and, more particularly, to jaw assemblies having jaws in which multiple 
workpiece-receiving cutouts can be formed. 
Soft jaws have been provided for use with manual and computer numerically 
controlled lathes to grip a workpiece during machining. Some soft jaws are 
reversible. Soft jaws heretofore provided, however, suffer from the 
disadvantage of having only two working portions in which cutouts can be 
formed for gripping the workpiece. Because of the foregoing, there is a 
need for a new and improved jaw assembly which overcomes the above named 
disadvantages. 
In general, it is an object of the present invention to provide a jaw 
assembly having jaws in which at least three workpiece-receiving cutouts 
in circumferential spaced-apart position can be formed in each jaw. 
Another object of the invention is to provide a jaw assembly of the above 
character in which each jaw is mountable to a chuck in at least three 
different positions. 
Another object of the invention is to provide a jaw assembly of the above 
character in which the jaws are repeatably registerable with the chuck in 
each position to facilitate remachining of a workpiece.

In general, the jaw assembly of the present invention is for use with a 
lathe chuck which is rotatable about an axis and provided with at least 
two first cooperative mating means circumferentially spaced-apart about 
the axis. The jaw assembly includes at least two cylindrical bodies. Each 
body has a longitudinal axis, a cylindrical outer surface and first and 
second spaced-apart generally parallel outer planar surfaces disposed in 
planes generally perpendicular to the longitudinal axis and to the 
cylindrical outer surface. Each body is adapted to have at least three 
circumferentially spaced-apart workpiece-receiving cutouts therein 
extending through at least the outer cylindrical surface and the first 
planar surface. Each body carries second cooperative mating means for 
mating with the first cooperative mating means of the chuck to secure the 
body to the chuck so that the body rotates in an immovable manner with 
respect to the chuck. The bodies are mountable with respect to the chuck 
to rotate therewith in at least three different positions. 
More in particular, jaw assembly 21 of the present invention is for 
rotatably securing a workpiece 22 to a lathe to permit shaping or other 
machining of the workpiece. The lathe, which can be a computer numerically 
controlled lathe as partially shown in FIG. 1, includes a chuck 23 which 
is rotatable about a central axis 26 and is provided with a plurality of 
at least two first cooperative mating means or portions. Chuck 23 as 
illustrated in FIG. 1 includes at least three cooperative mating portions 
and, in this regard, has three elongate adjustment members or slide bars 
27 which extend radially from central axis 26 and are circumferentially 
spaced-apart about axis 26 at approximately equal angular distances of 
120.degree.. Each slide bar 27 is movable inwardly and outwardly with 
respect to the central axis and includes an outer surface 28 and a central 
channel 29 which is generally the shape of an inverted T when viewed in 
cross-section and which opens longitudinally along the center of outer 
surface 28. An inverted T-member or slide member 31 is slidably disposed 
in channel 29 and has a raised guide or rail 32 extending up from the 
channel longitudinally along the center of outer surface 28. The portion 
of rail 32 exposed above surface 28 is generally rectangular in 
cross-section. Two longitudinally spaced-apart threaded bores 33 extend 
perpendicularly into each rail 32. A plurality of V-shaped serrations 34 
are formed on outer surface 28 along each side of channel 29 and extend 
generally perpendicularly from channel 29 in a transverse direction along 
outer surface 28. 
Jaw assembly 21 includes at least two cylindrical soft jaws and as shown in 
FIG. 1 three cylindrical soft jaws 36 mountable to chuck 23. Each jaw 36 
is formed from a cylindrical body 37 made of any suitable material such as 
aluminum and having a central longitudinal axis 41. Each cylindrical body 
37 is generally circular in cross section and includes a cylindrical or 
circular outer surface 42. First and second spaced-apart generally 
parallel planar surfaces 43 and 46 are disposed in planes generally 
perpendicular to longitudinal axis 41 and to outer surface 42. Jaws 36 
have a transverse dimension or diameter ranging from approximately 40% to 
50% and preferably approximately 45% of the transverse dimension or 
diameter of chuck 23 and a thickness measured by the distance between 
surfaces 43 and 46 ranging from approximately 1.5 to 6.0 inches and 
preferably approximately 2 inches. 
Each jaw 36 is adaptable to have at least three circumferentially 
spaced-apart working portions with workpiece-receiving cutouts formed 
therein. In the embodiment of jaw assembly 21 illustrated in the drawings, 
each jaw 36 is provided with a plurality of at least four cutouts which 
are identified therein as first, second, third and fourth cutouts 51, 52, 
53 and 54 and are spaced circumferentially about the jaw at angular 
distances of approximately 90.degree.. The cutouts extend through at least 
first surface 43 and outer surface 42 and are formed in part by an arcuate 
gripping surface 56 which extends perpendicularly through surface 43 and 
has a contour and as shown a radius generally equal to that of workpiece 
22. It should be appreciated that the cutouts can also extend through 
second surface 46 and be within the scope of the present invention. 
Second cooperative mating means is carried by each cylindrical body 37 for 
mating with a slide bar 27 of chuck 23 and securing the body to the chuck 
so as to rotate the body in an immovable manner with respect to the chuck. 
The cooperative mating means of each body 37 includes four grooves 61 
formed in second surface 46. Each groove 61 extends along the second 
surface in a radial direction from longitudinal axis 41 and has a 
cross-section configured and sized for snug disposition about a rail 32. 
The grooves intersect at longitudinal axis 41 at approximately right 
angles and are circumferentially disposed along surface 46 so that one of 
the grooves angularly corresponds about axis 41 with the centerline of one 
of cutouts 51, 52, 53 or 54 extending through surfaces 42 and 43 of the 
body. 
Each cylindrical body 37 is provided with a central bore 62 extending along 
longitudinal axis 41 between first and second surfaces 43 and 46 and four 
circumferentially disposed bores 63 extending between surfaces 43 and 46 
in a direction generally parallel to longitudinal axis 41. Bores 63 are 
circumferentially spaced-apart about axis 41 at equal angular distances of 
approximately 90.degree.. In this manner, central bore 62 is disposed 
between one pair of bores 63 in linear alignment along one diameter of 
body 37 and between the other pair of bores 63 in linear alignment along a 
second diameter of the body which is generally perpendicular to said first 
diameter. Bores 63 are disposed in cylindrical body 37 so that one bore 63 
opens into each groove 61 in second surface 46. The distance between 
central bore 62 and each bore 63 generally corresponds to the distance 
between spaced-apart threaded bores 33 of slide bars 27. Each of bores 62 
and 63 is formed with an enlarged counterbore 66 which opens into first 
surface 43. 
A pair of bolts 67 are utilized for mounting each jaw 36 to chuck 23. One 
bolt 67 extends through central bore 62 and the second bolt 67 extends 
through one of bores 63. Bolts 67 have heads 68 which seat within counter 
bores 66 and threaded ends (not shown) which threadedly engage threaded 
bores 33 of slide bars 27. 
Each cylindrical body 37 has registration means which includes first, 
second, third and fourth sets of grooves or serrations 71, 72, 73 and 74 
for permitting repeatable relative alignment between cylindrical jaws 36 
and chuck 23. These serrations are formed in second surface 46 so as to be 
elevated thereabove and are configured and sized so as to cooperatively 
mate with serrations 63 of slide bars 27. In this regard, serrations 71, 
72, 73 and 74 are generally V-shaped in cross-section. One set is provided 
for each groove 61 and each set has portions which extend along opposite 
sides of a groove in directions transverse to an imaginary line extending 
from longitudinal axis 41 along the groove. More specifically, each set of 
serrations extend at generally right angles to the corresponding groove 
61. Adjacent sets of serrations 71, 72, 73 and 74 intersect at 
approximately right angles at the radially inward portions thereof to form 
a grid-like pattern of pyramid-shaped elements 76. 
In operation and use, cylindrical jaws 36 are mountable to chuck 23 in at 
least three different positions and as shown in FIGS. 2 through 5 in at 
least four different positions for permitting, for example, repeatable 
work on four different workpieces 22. In this process, three blank 
cylindrical jaws 36 having no cutouts formed therein are mounted to the 
three slide bars 27 and the three slide members 31 carried by the slide 
bars. Cylindrical bodies 37 are longitudinally positioned on the slide 
members so that central bores 62 and one of bores 63 align with the two 
threaded bores 33 of the slide members. In many instances, the radially 
outermost bores 63 will be utilized with central bores 62 for mounting 
bodies 37 to chuck 23. 
After bolts 67 are inserted through bores 62 and 63 and are generally 
engaged with bores 33 of slide members 31, the cylindrical bodies and the 
slide members are moved radially relative to slide bars 27 so jaws 36 are 
in the generally desired position on chuck 23. Serrations 34 and 
corresponding serrations 71, 72, 73 or 74 are longitudinally aligned along 
rail 32 and groove 61, respectively, so as to permit exact alignment 
between jaws 36 and chuck 23. Once bolts 67 are tightened and cylindrical 
jaws 36 have been secured to slide bars 27, the cooperative mating of 
rails 32 and grooves 61 and of serrations 34 and corresponding serrations 
71, 72, 73 or 74 facilitate the cylindrical jaw rotating in an immovable 
manner on chuck 23. 
Once jaws 36 have been mounted to chuck 23, a first cutout 51 corresponding 
to the workpiece 22 desired to be machined is formed in jaws 36. Slide 
bars 27 are moved radially outwardly from central axis of rotation 26 so 
as to further separate jaws 36 and workpiece 22 is placed inside cutouts 
51. Slide bars 27 and jaws 36 are moved radially inwardly so that gripping 
surfaces 56 of the jaws snugly secure the workpiece to chuck 23 and permit 
rotation of the workpiece about central axis 26 of the chuck. 
Jaws 36 can be alternately mounted or positioned on chuck 23 so that 
second, third, and fourth cutouts 52, 53 and 54 can be formed therein as 
illustrated in FIGS. 3, 4 and 5. In reconfiguring the cylindrical jaws on 
the chuck, the bolts 67 extending through central bores 62 of the jaws are 
loosened slightly and the other bolts 67 extending through the radially 
outermost bores 63 are removed to permit rotation of the jaws about the 
bolts extending through central bores 62. A second groove 61 for each jaw 
is aligned about rail 32 of the corresponding slide bar 27 and the jaws 
resecured to the chuck with bolts 67 in a manner similar to that discussed 
above. 
Cylindrical jaws 36 securely grip workpiece 22 during machining. When the 
cylindrical jaws are in their operative position as shown in the drawings, 
they are in relatively close proximity to each other. Corresponding 
aligned cutouts 51, 52, 53 and 54 and gripping surfaces 56 thereof extend 
around almost the full circumference of the workpiece so as to provide a 
continuous and firm grip thereabout during machining. 
If the lathe operator desires to reutilize one of the sets of cutouts 51, 
52, 53 or 54 formed in cylindrical jaws 36, the operator can easily 
reconfigure cylindrical jaws 36 on chuck 23 so that the desired cutouts 
are in a cooperative and operative position on the chuck. The cooperative 
mating of serrations 71, 72, 73 or 74 provided on second surface 46 of the 
cylindrical jaws with serrations 34 on slide bars 27 permit repeatable 
relative alignment between the cylindrical jaws and the chuck in this 
regard. 
In another embodiment of the present invention, a jaw assembly 81 is 
provided which is particularly suitable for manual lathes (see FIGS. 7 and 
8). Jaw assembly 81 is for use with a chuck 82 rotatable about a central 
axis 83 and provided with a plurality of elongate slide bars 86 movable 
radially inwardly and outwardly with respect to central axis 83. Slide 
bars 86 each have a rail 87 extending longitudinally along the center 
thereof and are provided with spaced-apart threaded bores 91 extending 
into the rail. An indexing or registration recess 92 is formed in rail 87 
between bores 91. 
Jaw assembly 81 includes three cylindrical jaws 96 which are substantially 
similar to cylindrical jaws 36. Each jaw 96 is formed from a cylindrical 
body 97 having a central longitudinal axis 101 and a cylindrical or 
circular outer surface 102 extending about longitudinal axis 101. First 
and second spaced-apart generally parallel planar surfaces 103 and 106 
extend in planes generally perpendicular to longitudinal axis 101 and 
outer surface 102. Although not shown in the drawings, at least four 
cutouts similar to the cutouts formable in cylindrical jaws 36 can be made 
in each cylindrical jaw 96. 
Means for mounting cylindrical jaws 96 to chuck 82 is provided and includes 
four bores 107 extending circumferentially about longitudinal axis 101 at 
generally equal angular distances of approximately 90.degree.. As so 
disposed, each pair of bores 97 disposed on opposite sides of longitudinal 
axis 101 are generally colinear with an imaginary line extending through 
longitudinal axis 101 and are spaced-apart a distance so as to correspond 
to the spacial distance between threaded bores 91 of slide bars 86. Four 
grooves 111 are formed in second surface 106 of each cylindrical body 97. 
Grooves 111 extend radially outwardly from longitudinal axis 101 and are 
circumferentially spaced-apart so that a pair grooves 101 on either side 
of longitudinal axis 101 are in general linear alignment and at right 
angles to the other pair of grooves 111 which also extend from opposite 
sides of longitudinal axis 101 in general linear alignment. One of bores 
107 extends into each groove 111. 
Cylindrical jaws 96 include means for registering the jaws with slide bars 
86 of chuck 82. In this regard, a key member or a key 112 is removably 
mounted to the inside of grooves 111 where the grooves intersect on second 
surface 106 at longitudinal axis 101. Each key 112 is generally in the 
form of a parallelepiped having opposite first and second generally 
parallel and planar surfaces 113 and sides 116 extending between surfaces 
113. Cutouts 117 extend between each corner of surfaces 113. Each key 117 
is sized so as to be snugly disposed within grooves 111 at their 
intersection and cutouts 117 form portions 121 which extend partially down 
each groove 111 in a direction away from longitudinal axis 101. The key is 
secured to second surface 106 by any suitable means such as a recessed 
bolt 122 extending through a bore (not shown) between first and second 
surfaces 103 and 106 and into a threaded bore (not shown) provided in 
second surface 106 along longitudinal axis 101. The distance between 
surfaces 113 and the distance between sides 116 are sized so as to prevent 
relative snug disposition of key 112 into registration recess 92 of slide 
bars 86 and, in this regard, the outer surface of key 122 is elevated or 
spaced above second surface 106 of body 97. 
In operation and use, cylindrical jaws 96 are mountable to chuck 82 in an 
immovable manner in at least four different positions. Key extension 
portions 121 facilitate nonrotative engagement between keys 117 and 
cylindrical bodies 97 and hence between jaws 96 and chuck 82. The 
cooperative mating between keys 112 and registration recesses 92 ensures 
repeatable relative alignment between jaws 96 and chuck 82 in each of 
these positions. 
From the foregoing, it can be seen that a new and improved jaw assembly has 
been provided in which at least three workpiece-receiving cutouts in 
circumferential spaced-apart position can be formed in each jaw of the 
assembly. The jaws are mountable to a chuck in at least three different 
positions and are repeatedly registerable with the chuck in each position 
to facilitate remachining of a workpiece.