Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
1998-10-07
2001-03-20
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S522100, C029S898051
Reexamination Certificate
active
06202280
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
This invention relates to the manufacturing and assembly of movable sockets, for example, ball joints as used in automotive steering and suspension systems, and more particularly, to a method and device for closing one end of a movable socket without spinning, swaging, or welding, by means of an expanding cover-plate. While the invention is described in detail with respect to automotive applications, those skilled in the art will recognized the broader applicability of the invention.
Conventional ball joints, and other movable sockets are used, for example, in automotive steering and suspension applications. The sockets comprise a housing having a circular cylindrical internal surface, a ball stud with a ball head contained in the housing, and a synthetic resin or sintered alloy bearing member supporting the ball head within the housing. These components are installed into the housing through a posterior opening, with the ball stud extending outward through an axially disposed anterior opening of a smaller diameter than the ball head. Traditionally, the posterior opening is closed by means of a cover-plate, spun, swaged, or welded in place. Once secured in place, the cover-plate presses on the bearing member either directly or indirectly through a resilient rubber intermediate component.
Bearing components within the housing, against which the ball head or moveable component is articulated, perform best when the housing material is fully hardened, as it is better able to withstand the stresses and frictional wear associated with movement of the bearing components. Accordingly, the use of hardened materials greatly extends the useful life of the bearing components and the housing. However, hardened material surfaces greatly hinder traditional spinning, sagging, or welding operations required to enclose the housing. Therefore, specialized heat treatment operations such as induction draw operations, or a reduction in the allowable hardness levels of the housing and bearing material surfaces must be employed when using traditional assembly methods. These options are utilized to prevent the housing from cracking during swaging or spinning operations. Welding is an alternative to swaging or spinning operations for securing the cover to the housing. However, welding hardened materials is a difficult and costly operation, and not commonly employed.
Accordingly, it is highly advantageous to develop an assembly method and associated components capable of enclosing a fully hardened housing without the need for specialized spinning, swaging, or welding operations.
BRIEF SUMMARY OF THE INVENTION
Among the several objects and advantages of the present invention are:
The provision of an assembly method for a movable socket employing an expanding cover-element to secure the socket components within a socket housing;
The provision of the aforementioned assembly method wherein the socket housing is fully hardened;
The provision of the aforementioned assembly method wherein the socket housing includes a counterbore adjacent the posterior opening, and an expanding cover-plate is seated on the counterbore prior to expansion;
The provision of the aforementioned assembly method wherein the expanding cover-element is expanded in-place by the application of direct pressure;
The provision of the aforementioned assembly method wherein direct pressure is applied to the expanding cover-element by means of a ram;
The provision of the aforementioned assembly method wherein the ram face is configured to alter the angle of applied pressure exerted on the expanding cover-element during the expansion process;
The provision of the aforementioned assembly method wherein the expanding cover-element deforms from a conic or convex shape to a generally planar configuration during the expansion process; and
The provision of the aforementioned assembly method wherein no deformation or displacement of the housing material is required during assembly, allowing for an increase in material hardness, extending the useful service life of the movable socket.
Briefly stated, the present invention features an assembly technique for closing a movable socket without the need to deform or displace the portion of the socket housing, thereby allowing for the use of fully hardened materials for the socket housing. During assembly, various internal components of the movable socket are installed within the housing through an opening, and a conical or convex cover-element, for example, is positioned over the components, within the opening. A ram or similar device configured to exert pressure on the cover-element is brought into engagement with the cover-element, and a downward force applied, expanding the element. A specifically contoured face on the ram alters the angle at which pressure is exerted against the expanding cover-element as the plate deforms to close the opening in the housing, ensuring a generally planar final configuration. Once expanded, the cover-element is retained within a groove formed in the interior surface of the housing, thereby securing the various internal components within the housing.
The foregoing and other objects, features, and advantages of the invention as well as presently preferred embodiments thereof will become more apparent from the reading of the following description in connection with the accompanying drawings.
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patent: 6125541 (2000-10-01), Parker
Blount Steve
Federal-Mogul Corporation
Hughes S. Thomas
Polster Lieder Woodruff & Lucchesi L.C.
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