BALL JOINT WITH A RETAINER/SAFETY NUT THAT PREVENTS ACCIDENTAL SEPARATION OF THE BALL STUD AND THE SOCKET

Abstract

This invention relates in general to ball joints, such as are commonly used in motor vehicle steering and suspension systems (inclusive of upper ball joints, lower ball joints and tie rod ends). The invention is particularly aimed at preventing motor vehicle accidents that are caused by accidental separation of ball joints or tie-rod ends. In particular this invention relates to a ball joint assembly having shafts on both sides of the ball and a socket with openings on both sides to accommodate the two shafts. The main shaft, as is found in standard ball joints, serves the purpose of joining components while the second shaft has a retainer/safety nut, which prevents accidental separation of the ball joint. The retainer nut ensures that the ball cannot come out of the socket in the event of ball and socket wear. The side of the socket that has the retainer nut can be closed by either welding, press-fitting or by way of a cap that is screwed into the socket. For the version with a screw-in cap, the cap can be screwed into the socket towards the ball to eliminate free play. After screwing in the cap, the retainer nut must also be adjusted accordingly. The cap can also be unscrewed and removed for the purpose of renewing the ball joint to replace worn out polymer bearing using pre-molded replacement polymer bearings. Both shafts are protected from dust and natural elements by rubber boots.

Description

BACKGROUND OF THE INVENTION

This invention relates in general to ball joints, such as are commonly used in vehicular steering and suspension applications to transmit force between a steering mechanism and a steered wheel of a vehicle. In particular, this invention is aimed at avoiding accidental separation of the ball joint assembly due to wear of both the ball and the socket. The invention also allows for renewal of the ball joint by allowing for replacement of the polymer bearing. The design includes a retainer/safety nut for preventing accidental separation of the components of the ball joint as a result of such wear.

Ball joints are well known structures that are used in a variety of mechanical linkages. For example, ball joints are commonly used in vehicular steering and suspension assemblies to allow front wheels to turn sideways and also to transmit force between a steering mechanism and a steered wheel of a vehicle. A typical ball joint includes a ball stud that is received within a lubricated socket. The ball stud includes a spherically-shaped head portion having an elongated shaft portion extending therefrom. The spherically-shaped head portion of the ball stud is received within and cooperates with a corresponding spherically-shaped recess formed in the socket. This arrangement positively connects the ball stud to the socket so as to permit some forces to be transmitted therethrough. This arrangement also allows the ball stud to pivot in any direction relative to the socket.

It has been found that after a period of use, the cooperating portions of the ball stud and the socket of the ball joint will experience wear. Such wear can create undesirable looseness between the ball stud and the socket of the ball joint, resulting in the generation of noise and misalignment between the ball stud and the socket. In extreme cases, such wear can contribute to or cause the accidental separation of the ball stud from the socket, resulting in a total failure of the ball joint. Accidental separation of the ball stud from the socket is common in areas with bumpy roads. Unfortunately, because the spherically-shaped head portion of the ball stud is received within the corresponding spherically-shaped recess formed in the socket, it is often difficult to determine how much wear has occurred within the ball joint without removing the ball joint from its application and disassembling the ball stud and the socket for inspection. Such removal and disassembly is time consuming and expensive. In extreme cases, wear of the ball stud from the socket can lead to motor vehicle accidents that are caused by the accidental separation of the ball joints or tie rod ends. Thus, it would be desirable to provide a device that prevents accidental separation of the ball joint as a result of such wear. It would also be desirable to provide a method for renewing the ball joint so as to prolong its service life.

DESCRIPTION

SUMMARY OF THE INVENTION

This invention relates to a retainer/safety nut that prevents the separation of the ball stud from the socket as a result of wear of the ball stud or socket. The improved ball joint design includes an additional opening on the socket to accommodate an additional shaft on the other side of the standard ball stud. The additional shaft has threads for fitting of a retainer/safety nut. The retainer/safety nut ensures that the ball does not leave the socket. The retainer nut is bell-shaped so as to allow for sideways movement of the shaft. The side of the socket that has the retainer nut can be closed permanently for example by welding or press-fitting a cap onto the socket or by way of a cap that is screwed into the socket. For the version with a screw-in cap, the cap can be screwed into the socket towards the ball to eliminate free play. After screwing in the cap, the retainer nut must also be adjusted accordingly. The retainer/safety nut and the whole ball joint assembly are protected from dust and natural elements by rubber boots. Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a ball joint with a retainer/safety nut and a screw-in cap in accordance with this invention.

FIG. 2 is a perspective view of the ball with shafts on either side of the ball showing preferred embodiments.

FIG. 3 is a perspective view of a ball joint with a retainer/safety nut and coil spring in accordance with this invention.

FIG. 4 is a perspective view of the tie rod assembly with a retainer/safety nut in accordance with this design.

DESCRIPTIVE KEY (REFER TO FIG. 2)

• • 1 ball
  • 2 Main stud
  • 3 auxiliary study for retainer nut
  • 4 hole for cotter/safety pin
  • 5 hole for cotter/safety pin
  • 6 retainer/safety nut
  • 7 socket
  • 8 polymer bearing
  • 9 rubber boot/dust cover
  • 10 rubber boot/dust cover
  • 11 screw-in cap

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (REFER TO FIG. 2)

• • The invention relates to ball joint assembly having a ball (1) with studs/shafts on both sides of the ball (2 &3). The main stud/shaft (2) is the same as the stud found in conventional ball joints. The auxiliary stud (3) is shorter than the main stud and is for holding the retainer/safety nut that prevents accidental separation.
  • Both shafts have holes for cotter/safety pins (4&5). The main shaft (2) holds the castle nut as in conventional ball joints.
  • The retainer nut (6) is bell shaped so as to allow the ball and studs to move in all directions.
  • The ball (1) and socket (7) function as a typical ball and socket assembly.
  • A polymer bearing (8) is fitted into the socket. Press fitting of the ball joint assembly or screwing-in of the socket cap ensures that the polymer bearing is tightly packed. The polymer bearing absorbs impact thereby protecting the ball and socket. It also serves to reduce friction between the ball and socket.
  • When the polymer bearing is worn, some up and down movement in the ball will result. This movement is a sign of wear and can be evidenced by a rattling noise coming from the vehicle suspension. The wear in the ball joint can also be felt by shaking the wheel up and down.
  • The end of the socket with the retainer nut can either be closed by way of press-fitting a cap or by way of a screw-in cap (11). For the version with a screw-in cap, the cap can be screwed into the socket towards the ball to eliminate free play (see FIGS. 3&4). After screwing in the cap, the retainer nut must also be adjusted accordingly.
  • The cap can be unscrewed and removed for the purpose of renewing the ball joint by way of replacing the worn-out polymer bearing using pre-molded replacement polymer bearings. This prolongs the service life of the ball joint.
  • The ball and socket are protected on both sides by rubber boots (9 & 10). The boots are held firmly in place by rings as in conventional ball joints.
  • As the ball wears, the ball moves in the direction of the main shaft bringing the retainer nut into contact with the socket, thereby preventing accidental separation of the ball and socket.
  • A coil spring can be added to this design between the socket and the retainer/safety nut to reduce impact and vibration which may result from wear of the ball and socket (see FIG. 3).

The present invention may be used as a substitute for a conventional ball joint or may be installed in new vehicles. The invention may also be used in other non-motor vehicle applications that require ball joints. The invention can be used on all-steel ball joint that use grease for eliminating friction, as well as on low-friction ball joints that use polymer bearings. The invention can also be used with load carrying and non-load carrying ball joints.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention and method of use to the precise forms disclosed. Obviously many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application, and to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions or substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

Claims

1. A ball joint assembly having studs on both sides of the ball: a ball adapted to fixedly receive the first component; said ball having an additional shaft portion the ball defining a central axis of symmetry there through, said shaft portion being threaded to receive a V-shaped retainer/safety nut; a nut adapted to allow the ball to move in all directions. Some significant amount of wear in the ball portion and the socket causes the retainer nut to move closer to the socket. Wear also causes some upward and sideways movement in the ball and socket assembly.

2. The additional stud described in claim 1 is shorter than the standard stud and has threads and a hole for the cotter pin for the bell-shaped retainer nut.

3. The bell-shaped retainer nut described in claim 1 allows the shaft to move in all directions up to a predetermined angle that is determined by the openings on both side of the socket. The retainer nut ensures that the ball cannot come out of the socket in the event of ball and socket wear.

4. The assembly defined in claim 1 is supported by polymer bearings at the upper and lower ends for absorbing impact. The polymer bearing also serves as an indicator. Once the polymer bearing wears out, some up and down movement will be evident in the ball assembly.

5. The retainer nut defined in claim 3 is locked using a cotter pin to ensure that it does not unwind and lead to accidental separation of the ball joint assembly.

6. The assembly defined in claim 1 is protected on both sides from dust and other natural elements by rubber dust covers. The said covers also contain some grease for keeping the assembly lubricated.

7. The socket described in claim 1 has two openings on opposite ends to accommodate the two studs.

8. The socket described in claim 1 can be sealed by screwing-in or pressing.

9. The screw-in type socket can be adjusted for ball and socket wear by further screwing in the socket cap. The screw in socket can also be opened and new polymer bearing added in.

10. The wear of the ball and socket can be tested by shaking the vehicle wheel up and down. In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.