Ball type universal joint and method of manufacture

A ball type universal joint construction where a ball member is rotatably received in a housing and a bearing structure interposed therebetween in a manner which limits the relative rotational degrees of freedom. The ball member has a spherical surface portion which includes axially extending bearing receiving slots and the housing has a cavity spherical surface portion which includes bearing receiving recesses in registry with the receiving slots. Ball type bearings disposed partially within the recesses and partially within the slots limit movement between the ball member and housing to articulated movement relative to each other. The housing also includes an access opening at one end face having an enlargement through which the ball member can be passed when rotated 90 degrees to its nominal, functioning position. This allows the ball member to be inserted into the housing through the enlargement while at the same time accommodating passage of the bearings into the housing recesses. Thereafter, the ball member is further rotated such that the receiving slots also partially receive the bearings and thus capture the ball member in an articulating, non-rotatable relationship in the housing.

BACKGROUND OF THE INVENTION 
This application pertains to the art of joint constructions and more 
particularly to universal joint constructions which inhibit relative 
rotation between the joint components about their longitudinal axes while 
permitting rotation about axes transverse to the longitudinal axes. Such 
permitted rotation is hereinafter referred to as articulation. 
The invention is particularly applicable to a ball type universal joint 
used at terminals for transmission cables or the like where the cables are 
allowed to articulate or move but not rotate about their longitudinal axes 
relative to the structures from which they are suspended. It will be 
appreciated, however, that the invention has numerous other applications 
including, for example, flexible power transmission connections, marine 
antenna connectors, drive shafts, universal joints, socket wrench joints, 
overhead hoist joints, and the like. 
Ball type universal joints are well known and generally include an inner 
ball element adapted for fixed connection to some associated structure. 
Typically, the ball member is received in a central cavity of a housing 
which is connected to some second associated structure. In some 
constructions, a race of ball bearings rotatably secured in a cage or 
other bearing retaining means is disposed a gap between the ball member 
and housing cavity. Each ball bearing is partially received in a slot in 
the ball member and in a matching slot in the housing. These slots have 
widths commensurate with the ball bearing diameters and lengths generally 
disposed axially of the joint. The cooperative association between the 
ball bearings and slots blocks or prevents relative rotation between the 
ball member and housing about their longitudinal axes while readily 
permitting articulated movement therebetween. The cage or other retaining 
means is necessary for maintaining the ball bearings operatively 
interposed between the housing and ball member and for preventing 
undesired disassociation of the bearings from the joint construction. 
Prior art ball type universal joints such as the construction described 
above generally require careful match-machining. Also, assembly thereof 
into a finished joint tends to be time consuming and difficult owing to 
the large number of components, particularly the ball bearings, which are 
involved. 
It has, therefore, been considered desirable to develop a new and improved 
joint construction and method of manufacture which would overcome the 
foregoing problems. The present invention is deemed to meet these needs 
and others in providing a new ball type universal joint which is easy to 
manufacture and assemble in a wide variety of sizes for practical 
application in many different environments. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided a universal 
joint construction which permits relative articulating movement and 
inhibits relative rotational movement between the joint components and 
thus, the associated structures which it connects. The joint includes a 
ball member having an exterior surface portion which lies substantially on 
the surface of a first sphere. The ball member is adapted to be fixedly 
interconnected with a first associated structure. The joint also includes 
a housing which has an axial cavity with an interior surface portion which 
lies substantially on the surface of a second sphere for rotatably 
receiving the ball member. The housing is adapted to be interconnected 
with a second associated structure. At least one bearing receiving recess 
is disposed in and substantially surrounded by the spherical surface 
portion of one of the ball member and housing cavity with a corresponding 
bearing receiving slot being disposed in the other. A bearing element is 
operatively interposed between the ball member and housing, being 
partially disposed in the recess and partially in the slot. In this 
manner, the bearing element acts to limit relative movement between the 
ball member and the housing to orientations in which the slot and recess 
register or overlap. 
According to a preferred construction of the invention, the width of the 
slot and the width of the recess are closely compatible with the width of 
the bearing element and the slot is disposed axially of the joint. 
Relative rotation between the ball member and the housing is thus 
prohibited while articulating movement is freely permitted. 
In accordance with another aspect of the present invention, a method of 
assembly for a ball type universal joint construction is provided. The 
joint itself includes a ball member having a ball spherical surface 
portion and opposed end faces laterally spaced apart from each other by a 
distance less than the diameter of the ball spherical surface portion. A 
housing includes an interior cavity having a cavity spherical surface 
portion with the cavity and ball spherical surface portions adapted for 
rotational mating engagement with each other. The cavity terminates in an 
access opening having an enlargement dimensioned for ball member passage 
therethrough. At least one bearing receiving recess is disposed in one of 
the cavity and ball spherical surface portions and a bearing receiving 
slot is disposed in the other portion. The method itself comprises: (a) 
inserting the ball member through the access opening enlargement into the 
housing cavity; (b) placing a bearing partially in the receiving recess; 
and, (c) rotating the ball member such that the bearing is also partially 
received in the receiving slot. When the joint construction is placed into 
use, the bearing facilitates free articulating movement between the ball 
member housing while preventing relative rotation therebetween. At the 
same time, inadvertent joint disassembly is prevented. 
The principal object of the present invention is the provision of a new 
universal joint and method for manufacturing same. 
Another object of the invention resides in a new ball type universal joint 
construction and method which are readily adapted to a wide variety of 
joint applications. 
Other objects and advantages for the invention will become apparent to 
those skilled in the art upon a reading and understanding of the following 
specification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to FIG. 1, the new universal joint construction includes a 
ball member A rotatably received in a housing B with a pair of bearings C 
being operatively interposed between the ball member A and the housing B 
to limit the rotational degrees of freedom therebetween. 
Referring more specifically to the ball member A which is illustrated in 
greater detail in FIGS. 2, 3, and 4, it is generally toroidal in shape 
having an exterior surface portion 10 which lies on a first sphere. An 
inner passage 12 and a ball-associated structure interconnecting means 14 
are adapted for interconnection with a first associated structure 16. A 
first ball member depression which, in the preferred embodiment, comprises 
a first slot 20 extending longitudinally or axially of ball member axis 
18, is disposed in the spherical ball member surface portion 10. The slot 
20 has a cross section which is configured to conform with the cross 
section of the bearing C, i.e., a semicircular trough. The slot 20 has a 
first end 22 adjacent a front face 24 of the ball member and a second end 
26 adjacent a rear face 28 of the ball member. At least one of the first 
and second ends is sufficiently unrestricted that the ball member is able 
to be rotated along the slot until the bearing member and the slot 
disengage. Such disengagement during use is undesirable but as will be 
shown below, it facilitates joint assembly. 
In the preferred embodiment, a second ball member depression in the form of 
a second slot 30 is disposed diametrically opposite the first slot 20. The 
second slot 30 has similar opposed ends 32 and 34 with at least one being 
substantially unrestricted. Two slots which are 180 degrees apart are 
preferred, however, it is contemplated that the universal joint may have 
only a single slot. In the orientation illustrated in FIG. 1, the pair of 
diametrically opposed slots provide a path along which the pair of 
bearings C roll as the ball is rotated up or down along the plane of the 
paper. When the ball is rotated back and forth, i.e., in and out of the 
plane of the paper, the bearings restrict any radial motion between the 
ball and socket. When the ball is moved in other directions, a combination 
of these actions occurs. 
In FIG. 1, the first associated structure 16 is shown as including a shaft 
40 which is rigidly connected with the ball member A. The shaft 40 
terminates at one end with shaft interconnecting means for interconnection 
with the ball interconnecting means 14. In the embodiment of FIGS. 1-4, 
the ball interconnecting means includes a plurality of spaced projections 
42 which are received in corresponding slots on the shaft 40 to form a 
bayonet or twist type of connection. A rear ledge 44 is disposed adjacent 
the rear face 28 to limit longitudinal reception of the shaft. A means for 
locking the shaft and ball member against rotation includes a plurality of 
threaded bores 46 which extend through the rear ledge 44 and which cut 
partially into the side wall of inner passage 12. Matching partial bores 
48 are cut into the shaft 40 such that set screws 50 are receivable in the 
bores to lock the shaft and ball member together. The ball and shaft 
interconnecting means may take any nunber of other forms or arrangements 
to accommodate use in a wide variety of environments. Such modifications 
do not, however, in any way depart from the overall intent or scope of the 
invention. 
In the embodiment of FIG. 1, the first associated structure 16 comprises a 
cable termination device for securely interconnecting the joint 
construction with a cable 52. One such cable termination device is 
illustrated in, for example, U.S. Pat. No. 4,189,620, issued Feb. 19, 1980 
to William F. Stange and assigned to the assignee herein. However, it is 
contemplated that many other types and styles of cable termination or 
interconnection devices may be satisfactorily utilized. Shaft 40 
advantageously includes a central passage or bore 54 to facilitate the 
passage of electrical leads or the like (not shown) into communication 
with cable 52. 
With reference to FIGS. 1, 5, 6, and 7, the housing B has a longitudinally 
or axially extending cavity for rotatably receiving the ball member. The 
cavity is defined in part by an interior surface portion 60 which lies 
substantially on the surface of a second sphere. The spherical cavity 
surface portion 60 is defined by a circular arc segment along the 
longitudinal axis 62 of the housing and a circular cross section 
transverse to the longitudinal axis. The length of the arc segment varies 
with the degree of relative movement or articulation between the shaft 40 
and the housing B which is to be permitted. In the assembled condition, 
the first and second spheres are concentric and have radii which allow the 
ball to rotate easily within the cavity without excessive wobble or 
vibration. In the preferred embodiment, the difference in the radii is 
approximately 0.005 inches, although this will vary with the precision of 
the joint construction to be produced. 
The housing cavity has a transverse front aperture 64 through which the 
shaft 40 projects and a transverse rear aperture 66. Adjacent the front 
aperture 64, the cavity has a limiting surface 68 which interacts with the 
surface of shaft 40 to limit the amount or degree of shaft articulation. 
The rear aperture 66 has an enlarged portion 70 which extends from the 
rear of the housing to the major diameter of the second spherical surface. 
This enlarged portion has a slightly greater width or cross section than 
the ball member A when disposed on its side to permit insertion of the 
ball member into the housing in a manner to be described. Also, the cavity 
spherical surface portion 60 has an annular channel 72 transversely 
therearound for carrying grease or lubricant to the interface betweeh the 
ball member A, the housing B, and the bearings C. A grease passage 74 
connects the grease channel 72 with a grease fitting 76. 
A first housing depression for receiving the bearing in the preferred 
embodiment is in the form of a first recess 80 and a second housing 
depression takes the form of a second bearing receiving recess 82. 
Recesses 80 and 82 are disposed in the cavity spherical surface portion 60 
with the same circumferential spacing as the first and second slots 20 and 
30, i.e., diametrically opposed. The recesses conform to the shape of the 
bearing C are, therefore, generally semispherical to restrain the bearings 
C between the housing and the ball member. Because each bearing C rotates 
within its associated recess as the ball member A is moved, it is 
desirable to minimize the frictional engagement between the recess and 
bearing. Therefore, and in addition to lubricants, various other means may 
be advantageously employed. The cavity spherical surface portion 60 and 
the recesses 80 and 82 are illustrated as being integral with the housing. 
Optionally, the cavity spherical surface portion 60 could be formed on a 
separate liner which is nonrotatably received within the housing B. 
The bearings C in the preferred embodiment comprise spherical or ball 
bearings. A ball bearing is preferred because it has the widest freedom of 
rotational movement for reducing friction. However, because the ball 
member A and the housing B are not rotatable around the longitudinal axis, 
the bearings C are generally only called upon to restrict rotary motion so 
that elliptical or a cylindrical bearings could also be used. The bearings 
are received directly in the recesses 80 and 82 which simplifies assembly. 
However, the bearings may also comprise more complex subassemblies such 
as, for example, a cylindrical sleeve in which a biasing spring and a ball 
member are retained. 
It will be appreciated, that the recesses and the slots may be reversed 
with the slots being formed in the housing B and the recesses being formed 
in the ball member A. It will further be appreciated that the length, 
width, and direction of the slots and the recesses determine the permitted 
degrees of freedom in the relative movement between the ball member A and 
the housing B. In the preferred embodiment, the slots extend 
longitudinally or axially with both the slots and recesses having 
transverse widths commensurate with the bearing diameters. The foregoing 
relationships prohibit relative rotation between the ball member and the 
housing about their longitudinal axes while permitting free relative 
movement or articulation about axes which are transverse to the 
longitudinal axis. If desired for some reason, a limited amount of 
rotational movement about the longitudinal axis can be introduced by 
increasing the transverse width of the slots. Further controlled 
combinations of articulation and rotation may be introduced by skewing the 
slots, by using nonlinear slots, by using enlarged recess, and the like. 
The housing B includes housing-associated structure connecting means for 
connecting the housing with some second associated structure. In the 
embodiment of FIG. 1, this connecting means comprises a mounting flange 
having a plurality of circumferentially disposed bores 90 to accommodate 
fixedly bolting the housing to some other associated structure. 
FIGS. 8 through 13 illustrate a method for assembling a ball type universal 
joint in accordance with the present invention. The ball type universal 
joint illustrated in FIGS. 8 through 13 is particularly adapted for 
transmitting rotational forces and torques, although it will be 
appreciated that the method of assembly is equally applicable to the 
embodiment of FIGS. 1 through 7. In the embodiment of FIGS. 8 through 13, 
like components are identified by like numerals with a primed (') suffix 
and new components are identified by new numerals. 
Referring to FIG. 8, the ball member A comprises a toroidal element having 
an exterior surface 10' which lies on the portion of a first sphere and a 
generally cylindrical splined inner passage 12' for receiving a shaft 40'. 
A pair of slots 20' and 30' which are recessed in the surface 10' extend 
from a front face 24' to a rear face 28'. The front and rear faces are 
disposed substantially parallel to each other and are laterally spaced 
apart by some distance which is less than the diameter of the spherical 
surface portion. 
The second associated structure with which the housing B is connected is 
shown as comprising a shaft 100. The housing B has an internal cavity 
which has a cavity spherical surface portion 60' and a front aperture 64' 
for receiving the ball member A. A pair of recesses 80' and 82' are 
disposed in the cavity spherical surface portion 60' and are surrounded 
thereby. It will be appreciated that because the ball member spherical 
surface portion 10' and the cavity spherical surface portion 60' are very 
close to the same diameter, the edge of the cavity spherical surface 
portion which is adjacent the opening 64' will have a diameter which is 
smaller than the diameter of the ball spherical surface portion 10'. This 
relationship has caused assembly difficulties with prior art universal 
joint constructions and such difficulties have generally necessitated use 
of more complex joint constructions and assembly procedures. 
In accordance with the subject invention, a new method of assembly for the 
above new universal joint is advantageously provided which allows the 
number of component parts to be reduced and facilitates ease of universal 
joint assembly. To that end, front aperture 64' in the housing B is 
provided with an enlarged portion 70'. This enlarged portion includes a 
pair of diametrically opposed slots, one of which 110 is visible in FIG. 8 
and designated by numeral 110, extending longitudinally and parallel from 
the major diameter of the spherical cavity surface portion 60' toward the 
cavity front aperture 64'. In the preferred embodiment, the slots are 
disposed 90 degrees circumferentially around the longitudinal axis 62' 
from the recesses 80' and 82'. The enlarged portion 70' has a height which 
is slightly larger than the width between the front and rear faces 24' and 
28' of the ball member A. 
With reference to FIG. 9, the ball element A is rotated 90 degrees from its 
nominal installed position into alignment with the enlarged portion 70'. 
The ball member is slid through the enlarged portion until the spherical 
surface portions 10' and 60' abut. 
With reference to FIG. 10, the ball member A is then rotated until 
sufficient clearance is provided between the ball member and the housing 
to allow bearings C to be passed therebetween. The bearings or the 
recesses 80' and 82' are coated with grease or other temporary adhesion 
means so that the bearings will adhere in the recesses. One bearing is 
passed between the ball member and the housing and pressed into the recess 
80'. The second bearing is dropped through passage 12' of ball member A 
into the recess 82'. Optionally, the bearings C may be positioned in the 
recesses 80' and 82' before the ball member A is inserted into the 
housing. 
With reference to FIG. 11, and once the bearings are disposed in the 
recesses, the ball member A is rotated and its orientation adjusted until 
the bearings are received in the slots 20' and 30'. A splined end 120 of 
shaft 40' is inserted into the splined passage 12' of the ball member A. 
Optionally, the interconnecting means may further include a key member, 
set screw, bonding agent, or the like between the splined passage 12' and 
the splined end 120 to improve the security of their connection. 
It will be appreciated that because the transverse width of the recesses 
80' and 82' and the transverse width of the slots 20' and 30' are 
commensurate with the size of the bearings C and because the slots 20' and 
30' extend axially of the ball member, the housing B and the ball member 
A, hence shafts 40' and 100, are locked against relative rotation about 
their axes 18' and 62', respectively. Rotational forces or torques applied 
to shaft 100 are thus conveyed through the housing B and bearings C to 
ball member A, through the splined interconnection of surfaces 12' and 120 
to shaft 40'. 
Referring to FIG. 12, the interaction of the slots 20' and 30' with the 
bearings C permit the shaft 40' and the ball member A to rotate about any 
axis transverse to the coaxial longitudinal axis of shaft 100 and housing 
B and to the longitudinal axis of shaft 40', i.e., an articulating type 
movement. The shaft 40' and ball member A are permitted to articulate 
until the surface of shaft 40' abuts the articulation limiting surface 68' 
of the housing. Rotational forces or torques about the longitudinal axis 
62' of shaft 100 and housing B are transmitted through the joint and 
result in rotational forces or torques being applied about the 
longitudinal axis 18' extending through the shaft 40' and ball member A. 
It will be appreciated that if the ball member A rotates too far relative 
to the housing B, the bearings C will be free to fall from the recesses 
80' and 82'. Such an extreme articulated position would, for example, have 
the components disposed in the manner illustrated in FIG. 10. To prevent 
the bearings from leaving the recesses, and referring again to FIG. 12, 
the longitudinal arc segment 130 spanned by the slots 20' and 30' is 
greater than the arc segment 132 spanned by the maximum limits of 
articulation. In this manner, the surface of the shaft 40' and the 
articulation limiting surface 68' limit articulation of the ball member 
such that the bearings are always retained within the slots 20' and 30'. 
FIG. 13 shows a grease fitting 76' connected with the housing B in 
communication with its interior cavity. This allows grease to be forced 
into the interface area between the cavity spherical surface portion and 
the ball member spherical surface portion to provide lubrication. A 
flexible, protective boot 140 is frictionally connected with bands 142 and 
144 to the exterior surface of the housing B and the shaft 40'. The 
protective boot is advantageously accordion pleated to enable it to flex 
between the limits of articulation. 
FIG. 14 shows yet another alternate embodiment of the present invention in 
which like elements are again identified by like numerals with a double 
primed (") suffix and new elements are identified by new numerals. Here, 
the ball member A has a spherical outer surface portion 10" with an axial 
bearing receiving slot 20". A first associated structure 16" is connected 
with an inner annular surface 12" of the ball member by interconnecting 
means which include mating annular shoulders 150 which are held firmly 
together by a set screw 50" and a locking screw 152. The housing B has a 
ball member receiving cavity with a spherical surface portion 60" and a 
bearing receiving recess 80". An annular flange 154 is adapted to receive 
mounting bolts 156 for securing the housing to a second associated 
structure. A front boot 160 and a rear boot 162 protect the joint 
construction from dirt and other contaminants. A cable 164 passes through 
the joint construction to the first associated structure 16". 
The invention has been described with reference to preferred and 
alternative embodiments. Obviously, further modifications and alterations 
will become apparent to those of ordinary skill in the art upon a reading 
and understanding of this specification. It is intended to include all 
such modifications and alterations insofar as they come within the scope 
of the appended claims or the equivalents thereof.