Abstract:
An assembly technique is provided for enclosing an open end of a movable socket comprised of fully hardened materials with an expanding solid cover-plate having a circumferential groove on either an upper or lower surface. Internal components of the movable socket are installed within a housing through a posterior opening and a expanding solid cover-plate having a circumferential groove on either an upper surface or a lower surface is positioned over the components within the posterior opening. A ram of the present invention having a configured contact surface is brought into engagement with the solid cover-plate, and pressure is exerted on the solid cover-plate. Pressure exerted by the ram is transferred to the cover-plate through the contact surface, deforming and expanding the cover-plate in a predetermined manner to close the socket housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     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 performing the operation of closing one end of a movable socket without spinning, swaging, or welding, by means of an expanding solid cover-plate. While the invention is described in detail with respect to automotive applications, those skilled in the art will recognize 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, heat treated steel, 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, which is spun or swaged in place, as seen in FIGS. 1A-1D. Alternatively, the cover-plate may be welded into place. 
     Cover-plate elements are traditionally formed from a stamping process, whereby individual components having desired dimensions are stamped from metal sheets. Either during the stamping process or in a subsequent manufacturing step, a raised boss may be drawn or stamped into the cover-plate, and a centrally located hole of predetermined dimensions punched therein to receive a self-tapping or threaded grease fitting. 
     Once secured in place, the cover-plate presses on the bearing member either directly or indirectly through a resilient rubber intermediate component and a pressure plate. 
     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, swaging, or welding operations required to enclose the housing. 
     Once assembled, movable sockets may be utilized as load carrying members in numerous mechanical systems, including automotive vehicle suspension and steering systems. Obviously, movable sockets or ball-joints employed in these applications are subjected to various operating conditions, and may be required to carry substantial loads. When wear develops, the performance of the movable socket or ball-joint degrades and, in the case of automotive applications, may result in erratic steering or excessive looseness and play in the vehicle suspension system. 
     As described in U.S. Pat. No. 6,202,280 B1, (herein incorporated by reference) a method and device for expanding a conical or convex cover-plate within the posterior opening may be employed to secure and enclose the socket components within the socket housing, allowing for closure of a fully hardened housing without the need for traditional spinning, swaging, or welding operations. 
     Alternatively, as is described in U.S. Pat. No. 6,125,541 to Parker, herein incorporated by reference, a two-stage ram having first and second contact surfaces may be utilized to first expand a conical or convex wear-indicator style cover-plate, having an axial opening, within the posterior opening of a housing, and then to further deform the cover-plate to a predetermined final position relative to the internal components of the socket to provide a predetermined wear indicator distance. 
     Similarly, as is described in co-pending U.S. Patent application Ser. No. 09/681,305, herein incorporated by reference, a two-stage ram having a contact surface and a concentric pivot punch may be brought into engagement with the cover-plate within the posterior opening of a housing for the purpose of closing the housing. Pressure exerted by the two-stage ram is transferred to the cover-plate through the contact surface, expanding the cover-plate to conform to the contact surface and enclosing the internal components within the socket housing. The exerted pressure additionally results in the extension of the concentric pivot punch into the central orifice of the cover-plate, controlling the expansion of the cover-plate and establishing the central orifice to predetermined dimensions upon closure of the socket housing. 
     Each of the aforementioned devices and methods for closing a movable socket with a ram requires that the cover-plate incorporate an axial opening to permit the desired deformation under load from the ram. However, some socket designs require a sealed or closed cover-plate having no axial opening. Such socket designs still utilize hardened housings, and therefore still have the same housing hardness issues as stated above. In many such applications, the socket is lubricated only prior to the assembly process, and is not lubricated after assembly. These are often referred to as “lubed for life” sockets. The socket closure devices and techniques previously described to overcome the housing hardness issues cannot be utilized with such “lubed for life” sockets, as cover-plates without axial openings will not properly deform under load from the ram, and accordingly, will not result in ideal socket closure. 
     Accordingly, it is highly advantageous to develop a ram device capable of expanding a solid conical or convex cover-plate within a socket housing to enclose the housing without the need for specialized spinning, swaging, or welding operations. 
     BRIEF SUMMARY OF THE INVENTION 
     Briefly stated, a first aspect of the present invention provides an expanding solid cover plate for closing one end of a movable socket. The expanding solid cover plate incorporates either an upper or lower circumferential groove to control and direct deformation of the solid cover-plate during an expansion process resulting in the solid-cover plate engaging and closing one end of a movable socket. 
     A second aspect of the present invention provides a ram stop-out plate configured to engage an expanding solid cover plate having either an upper or lower circumferential groove, and for directing an applied force to the solid cover plate, whereby the cover plate is deformed and expanded to close one end of a movable socket. 
     A third aspect of the present invention features an assembly technique for enclosing an open end of a movable socket comprised of fully hardened materials with an expanding solid cover-plate having a circumferential groove on either an upper or lower surface. During assembly, various internal components of the movable socket are installed within a housing through a posterior opening and a solid conical or convex cover-plate having a circumferential groove on either an upper or lower surface is positioned over the components within the posterior opening. A ram of the present invention having a contact surface is brought into engagement with the solid cover-plate. Pressure exerted by the ram is transferred to the cover-plate through the contact surface, deforming and expanding the cover-plate to close the socket housing. 
     A fourth aspect of the present invention is an assembly technique for enclosing an open end of a movable socket comprised of fully hardened materials with an expanding solid cover-plate so as to force a quantity of lubricant material to flow though the movable socket assembly during the closure process. Forcing the flow of lubricant through the socket assembly eliminates the need to pre-lubricate individual components prior to placement in the socket assembly. 
     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. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     In the accompanying drawings which form part of the specification: 
     FIG. 1A is a sectional view of a prior art apparatus for spin and swaging closure of a socket assembly; 
     FIG. 1B is sectional view of the prior art apparatus of FIG. 1A compressing the components of a socket assembly; 
     FIG. 1C is a sectional view of the prior art apparatus of FIG. 1A engaging and swaging the housing material of the socket assembly to entrap the cover-plate; 
     FIG. 1D is a sectional view of the prior art apparatus of FIG. 1A upon completion of the socket closing procedure; 
     FIG. 2 is an exploded view of one illustrative embodiment of a movable socket assembly employing the expanding cover-plate of the present invention; 
     FIG. 3 is a partial view illustrating the movable socket of FIG. 2, with the upper end components in-place, prior to expansion of the cover-plate; 
     FIG. 4A is a top view of one embodiment of an expanding solid cover-plate of the present invention, having an upper circumferential groove; 
     FIG. 4B is a side sectional view of the expanding solid cover-plate of FIG. 4A, taken along lines  4 B— 4 B; 
     FIG. 5A is a top view of one embodiment of an expanding solid cover-plate of the present invention, having a lower circumferential groove; 
     FIG. 5B is a side sectional view of the expanding solid cover-plate of FIG. 5A, taken along lines  5 B— 5 B; 
     FIG. 6A is a sectional view of a ram stop-out plate of the present invention together with an expanding solid cover-plate having an upper circumferential groove as seen in FIG. 4A positioned in a socket housing, prior to closure; 
     FIG. 6B is a sectional view of the ram stop-out plate of FIG. 6A applying a load to the expanding solid cover-plate, resulting in downward deformation thereof within the housing; 
     FIG. 6C is a sectional view similar to FIG. 6B, wherein continued application of a load on the expanding solid cover-plate by the ram stop-out plate results in cover-plate expansion; 
     FIG. 6D is a sectional view similar to FIG. 6C, wherein the ram stop-out plate has reached a maximum travel limit, contacting the housing surface; 
     FIG. 6E is a sectional view similar to FIG. 6D, wherein the ram stop-out plate has been withdrawn, and the housing sealed by the expansion of the solid cover plate with an upper circumferential groove; 
     FIGS. 7A through 7C illustrate the flow of a lubricant material through a socket housing assembly during the closure process illustrated in FIGS. 6A-6E; 
     FIG. 8A is a sectional view of a ram stop-out plate of the present invention together with an expanding solid cover-plate having a lower circumferential groove as seen in FIG. 5A positioned in a socket housing, prior to closure; 
     FIG. 8B is a sectional view of the ram stop-out plate of FIG. 8A applying a load to the expanding solid cover-plate, resulting in downward deformation thereof within the housing; 
     FIG. 8C is a sectional view similar to FIG. 8B, wherein continued application of a load on the expanding solid cover-plate by the ram stop-out plate results in cover-plate expansion; 
     FIG. 8D is a sectional view similar to FIG. 8C, wherein the ram stop-out plate has reached a maximum travel limit, contacting the housing surface; 
     FIG. 8E is a sectional view similar to FIG. 8D, wherein the ram stop-out plate has been withdrawn, and the housing sealed by the expansion of the solid cover plate with an lower circumferential groove; 
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description illustrates the invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the invention, describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention. 
     Referring generally to FIGS. 2 and 3 the two-stage expanding cover-plate assembly method of the present invention may be used to enclose a movable socket, such as the ball-joint shown at  10 , within a housing  12  without the need for spinning, swaging, or welding. Those skilled in the art will readily recognize the applicability of the following method to the assembly of a variety of different movable sockets; to facilitate the description of the method and devices used in conjunction therewith, the preferred embodiment of present invention is described in reference to a ball-joint  10 , but is not limited to use therewith. 
     Housing  12 , within which the various internal components of the ball-joint are enclosed, is generally cylindrical, with a central bore  14  of non-uniform radius having a posterior opening  16  and an anterior opening  18 . The radius R of central bore  14  decreases to define a curved surface  20  at the base of the housing, adjacent anterior opening  18 . A counterbore  22  having a circumferential groove  24  is formed in bore  14 , adjacent the posterior opening  16 . The exterior surface  26  of housing  12  may follow the general contour of the central bore  14 . In the embodiment illustrated, the surface  26  has an expanded ridge  28  formed in it. The ridge  28  is used for attachment of ball-joint  10  to other components (not shown). As may be appreciated, the ridge  28  also may be adapted for other specific kinds of installations employing threads or other connectors (not shown). 
     To assemble ball-joint  10 , a bearing  30  sized to fit within central bore  14  is seated within housing  12 . The bearing  30  includes a central bore  32  axially aligned with a vertical axis VA of the housing, and a curved outer surface  34  of bearing  30  is designed to correspond to the curvature of surface  20  in housing  12 . 
     Next, a stud  36  having a generally cylindrical body  38  and an enlarged head portion  40  with a circumferential flange  42  is passed through central bores  32  and  14 , such that the underside  44  of flange  42  rests on an upper surface  46  of the bearing seated within the housing. The body  38  includes a uniform diameter upper portion  50  adjacent flange  42 , a tapered central portion  52 , and a lower portion  54  of a narrow uniform diameter. The upper portion  50  is sized to fit within the central bore  32  of bearing  30 , with the central portion  52  and lower portion  54  extending through the anterior opening  18 , externally of housing  12 . The head portion  40  includes a hemispherical surface  56  with a radius RH greater than that of upper portion  50 , but less than radius R of the housing  12 . When assembled, the hemispherical surface  56  and the curved outer surface  34  define a generally spherical unit within housing  12 , allowing for conical movement of stud  36 . Those skilled in the art will readily recognize that numerous shapes and configurations for stud  36  and bearing  30  are possible. For example, the stud  36  may include a generally spherical head, eliminating the need for bearing  30 , or the cylindrical body may include threads (not shown), bores as at  58 , or grooves as at  60 , for attachment of external components (not shown). 
     Once stud  36  and bearing  30  are seated within the housing, a pressure plate  62  and a rubber cushion preload device  64  are placed within central bore  14 , above hemispherical surface  56 , and secured therein by an expanding solid cover-plate  66 . The pressure plate  62  sits on top of stud  36 , and includes a curved indentation  68  having a radius of curvature corresponding to R H , and an axial passage  70  formed in it. The rubber cushion preload device  64  sits, in turn, on an upper surface  72  of pressure plate  62 , and serves to hold the pressure plate  62  in place against the stud  36  while simultaneously permitting small movements in response to the conical movement of the stud. The rubber cushion preload device comprises a cylindrical body  74 , having an axial passage  76  formed in it. Finally, solid cover-plate  66 , shown in an un-expanded conical configuration in FIG. 2, is placed above the rubber cushion  64  adjacent counter-bore  22 , for vertical compression and lateral expansion as will be described, to seat within circumferential groove  24  and enclose the various components within housing  12 . To facilitate the insertion of the solid cover-plate  66  within the posterior opening of housing  12 , the solid cover-plate  66  includes a circumferential rim  78  having and outer diameter OD sized to fit within counter-bore  22 . FIG. 3 illustrates the arrangement of the ball-joint  10  upper components  36 ,  62 ,  64 , and  66  prior to the expansion of the solid cover-plate  66 . 
     As indicated above, those skilled in the art will recognize that the various internal components of the moveable socket secured within the housing  12  by the solid cover-plate  66  may be varied in size and shape depending upon the particular application for which the movable socket is designed, and accordingly, the above described ball-joint  10  is merely exemplary of one embodiment. 
     Turning next to FIGS. 4A and 4B, a first embodiment  100  of the expanding solid cover-plate  66  of the present invention is shown. The cover-plate  100  is symmetric about a central axis A, and in unexpanded form includes a central convex portion  101 , surrounded by a conical peripheral portion  106 . As seen in FIGS. 4A and 4B, the upper surface  102  of the cover-plate  100  includes a circumferential groove  104  disposed between the central convex portion  101  and the conical peripheral portion  106 . The circumferential groove  104  preferably has a depth of approximately 50% of the material thickness of the cover-plate  100 . The depth of the groove is selected so that when a sufficient force or load is placed on the cover-plate  100  during the socket closure process, a stress concentration occurs in the vicinity of the circumferential groove. The radial location R 100  of the circumferential groove  104  from the central axis A of the cover-plate regulates the final shape and configuration of the cover-plate  100  after closure of a movable socket housing  12 , as will be more clearly set forth below. 
     Turning next to FIGS. 5A and 5B, a second embodiment  200  of the expanding solid-cover plate  66  of the present invention is shown. The cover-plate  200  is symmetric about a central axis A, and in unexpanded form includes a central convex portion  201 , surrounded by a conical peripheral portion  206 . As seen in FIGS. 5A and 5B, the lower surface  202  of the cover-plate  200  includes a circumferential groove  204  disposed between the central convex portion  201  and the conical peripheral portion  206 . The circumferential groove  204  preferably has a depth of approximately 50% of the material thickness of the cover-plate  200 . The depth of the groove is selected so that when a sufficient force or load is placed on the cover-plate  200  during the socket closure process, a stress concentration occurs in the vicinity of the circumferential groove. The radial location R 200  of the circumferential groove  204  from the central axis A regulates the final shape and configuration of the cover-plate  200  after closure of a movable socket housing  12 , as will be more clearly set forth below. 
     Turning next to FIGS. 6A-6E, the utilization of a solid cover-plate  100  to close a movable socket housing  12  is shown in stages. In FIG. 6A, a solid cover-plate  100  is shown in an un-expanded convex configuration, placed adjacent counter-bore  22  in the housing  12 , for vertical deformation and lateral expansion to seat within circumferential groove  24  and enclose the various components within the housing  12 . A ram  300  is positioned above the solid cover-plate  100  and configured to exert a load onto the cover-plate  100 , thereby deforming and expanding it to close the housing  12 . 
     The basic design and operation of the ram  300  is described in detail in U.S. Pat. No. 6,202,280 B1, with improvements and adaptations for use with solid cover-plates set forth herein. The lower surface of the ram  300  is fitted with a removable stop-out plate  302  having a working face  304 , adapted to engage the solid cover-plate  100 . In the embodiment shown in FIGS. 6A-6E, the removable stop-out plate  302  comprises an axially located concave primary contact surface  306  having a spherical radius equal to the spherical radius of the central dome area  101  or  201  on the solid cover-plate  100  or  200  for which the stop-out plate  302  is adapted. The outer perimeter of the concave primary contact surface  306  has a radial displacement R PLATE  corresponding to the radial placement R 100  of the circumferential groove  104  in the solid cover-plate  100 . The primary contact surface  306  is surrounded by a raised toroid defining a secondary contact surface  308 . Radially outward from the toroid surface  308  is a flat final contact stop-out surface  310  adapted to contact the upper surface  312  of the housing  12  upon closure thereof. The final contact surface establishes the depth to which the cover-plate  100  or  200  is finally deformed. 
     As seen in FIG. 6B, the primary contact surface  306  of the stop-out plate  302  is brought into engagement with the convex upper surface  102  of the solid cover-plate  100 . The ram  300  is then utilized to exert an axially downward force on the solid cover-plate  100  through the stop-out plate  302 . Initially, stress and force concentrations in the region of the circumferential groove  104  in the solid cover-plate  100  cause an extrusion of the cover-plate material opposite the circumferential groove  104 . This extrusion of the cover-plate material results in the deformation of the cover-plate  100  into a flattened configuration, seen in FIG. 6C, as the inner convex portion  101  of the cover-plate  100  is pressed downward, closing the circumferential groove  104 . Simultaneously, the outer conical perimeter  106  of the solid cover-plate  100  is contacted by the toroid surface  308  of the stop-out plate  302 , and is forced into engagement with the circumferential groove  24  formed in the bore  14  of the socket housing  12 . 
     As seen in FIGS. 6C and 6D, continued exertion of axially downward force on the solid cover-plate  100  by the toroid surface  308  of the stop-out plate  302  causes a lateral expansion of the outer conical peripheral  106  of the solid cover-plate  100  into a generally flat configuration by redirecting downward forces exerted by the ram  300  into radially outward forces, resulting in a expansion engagement between the cover-plate  100  and the circumferential groove  24  in the socket housing. Additionally, the inner convex portion  101  of the cover-plate  100  acts to restrict any inward radial movement of the outer conical peripheral portion  106 , as it is restrained from deformation by the primary contact surface  306 , further resulting in greater outward expansion of the cover-plate  100 . Downward force is exerted by the ram  300  until the final contact stop-out surface  310  contacts the upper surface  312  of the housing  12 , preventing further downward movement thereof. 
     As seen in FIG. 6E, following contact between the upper surface  312  of the housing  12  and the stop-out plate  302  of the ram  300 , the ram  300  is withdrawn, and the socket closure procedure is complete. The solid cover-plate  100  is fully engaged with the circumferential groove  24 , closing the housing. The convex central portion  101  of the cover-plate remains in the form of a raised central dome or boss, providing clearance for the internal components of the socket housing. The circumferential groove  104  is completely closed by the deformation of the cover-plate during the closure process, and a portion of the cover-plate  100  opposite the circumferential groove  104  extends downward into the bore  14  of the socket housing below the level of the flattened outer conical peripheral  106 . 
     Turning next to FIGS. 7A-7C, an additional feature of the above-described closure method for a movable socket utilizing an expanding solid cover-plate is shown. Specifically, a quantity of lubricant material  400 , such as grease or the like, is placed into the socket housing  12  prior to the placement of the solid cover-plate  100  into the socket bore  14 . (FIG.  7 A). The solid cover-plate  100  is then positioned within the socket bore  14  for the commencement of the deformation and expansion closure procedure described above. (FIG.  7 B). The socket housing  12  is then closed by the deformation and expansion of the solid cover-plate  100  under the forces exerted by the ram  300 . As is seen in FIG. 7C, the lubricant material  400  is forced, under pressures exerted by the closure of the socket  12 , to flow into voids and gaps between the components placed within the socket housing  12 . Trapped air and any excess quantities of lubricant material  400  exit the socket housing anterior opening  18 , around the cylindrical body  38  of the stud  36 . In this manner, the lubricant material  400  is evenly distributed throughout the voids and gapes between the components in the housing  12 , generally providing sufficient lubrication for the useful operational life of the socket. 
     Turning next to FIGS. 8A-8E, the utilization of a solid cover-plate  200 , having a circumferential groove  204  on the lower surface, to close a movable socket housing  12  is shown in stages. As was previously shown with the solid cover-plate  100  in FIGS. 6A-6E, in FIG. 8A an unexpanded solid cover-plate  200  is placed adjacent counter-bore  22  in the housing  12 , for vertical deformation and lateral expansion to seat within circumferential groove  24  and enclose the various components within the housing  12 . The ram  300  is positioned above the solid cover-plate  200  and configured to exert a load onto the cover-plate  200 , thereby deforming and expanding it to close the housing  12 . 
     As previously described, the lower surface of the ram  300  is fitted with a removable stop-out plate  302  having a working face  304 , adapted to engage the solid cover-plate. In the embodiment shown in FIGS. 8A-8E, the removable stop-out plate  302  comprises an axially located concave primary contact surface  306  having a spherical radius equal to the spherical radius of the central dome area  201  on the solid cover-plate  200  for which the stop-out plate  302  is adapted. The outer perimeter of the concave primary contact surface  306  has a radial displacement R PLATE  corresponding to the radial placement R 200  of the circumferential groove  204  in the solid cover-plate  200 . The primary contact surface  306  is surrounded by a raised toroid defining a secondary contact surface  308 . Radially outward from the toroid surface  308  is a flat final contact stop-out surface  310  adapted to contact the upper surface  312  of the housing  12  upon closure thereof. The final contact surface establishes the depth to which the cover-plate  200  is finally deformed. 
     As seen in FIG. 8B, the primary contact surface  306  of the stop-out plate  302  is brought into engagement with the convex upper surface  202  of the solid cover-plate  200 . The ram  300  is then utilized to exert an axially downward force on the solid cover-plate  200  through the stop-out plate  302 . Initially, stress and force concentrations in the region of the circumferential groove  204  in the solid cover-plate  100  cause an expansion of the circumferential groove  204 . This expansion of the cover-plate material results in the deformation of the cover-plate  200  into a flattened configuration, seen in FIG. 8C, as the inner convex portion  201  of the cover-plate  200  is pressed downward. Simultaneously, the outer conical perimeter  206  of the solid cover-plate  200  is contacted by the toroid surface  308  of the stop-out plate  302 , and is forced into engagement with the circumferential groove  24  formed in the bore  14  of the socket housing  12 . 
     As seen in FIGS. 8C and 8D, continued exertion of axially downward force on the solid cover-plate  200  by the toroid surface  308  of the stop-out plate  302  causes a radial expansion of the outer conical peripheral  206  of the solid cover-plate  200  into a generally flat configuration by redirecting downward forces exerted by the ram  300  into radially outward forces, resulting in a expansion engagement between the cover-plate  200  and the circumferential groove  24  in the socket housing. Additionally, the inner convex portion  201  of the cover-plate  200  acts to restrict any inward radial movement of the outer conical peripheral portion  206 , as it is restrained from deformation by the primary contact surface  306 , further resulting in greater outward expansion of the cover-plate  200 . Downward force is exerted by the ram  300  until the final contact stop-out surface  310  contacts the upper surface  312  of the housing  12 , preventing further downward movement thereof. 
     As seen in FIG. 8E, following contact between the upper surface  312  of the housing  12  and the stop-out plate  302  of the ram  300 , the ram  300  is withdrawn, and the socket closure procedure is complete. The solid cover-plate  200  is fully engaged with the circumferential groove  24 , closing the housing. The convex central portion  201  of the cover-plate remains in the form of a raised central dome or boss, providing clearance for the internal components of the socket housing. The circumferential groove  204  is further expanded by the deformation of the cover-plate during the closure process, and a portion of the cover-plate  200  adjacent the inner edge of the circumferential groove  204  remains above the level of the flattened outer conical peripheral  206  within the socket bore  14 . 
     Those of ordinary skill in the art will readily recognize that the embodiments of the present invention shown herein may be varied depending upon the particular application for which the movable socket it to be utilized. Specifically, the placement of the circumferential groove on the solid cover-plate, on either the upper or lower surface, as well as the radial location thereof, affects the final configuration of the expanded and deformed cover-plate after closure of a socket. The radial location of the circumferential groove defines the size of the central dome or boss of the deformed and expanded cover plate. Similarly, placement of the circumferential groove on either the upper or lower surface of the cover-plate defines the amount of cover-plate material which will extrude below the flattened cover-plate after closure of a socket. 
     Correspondingly, the design of the working face of the stop-out plate on the ram utilized to close the socket with a solid cover-plate of the present invention is dependent upon the configuration of the solid cover-plate being utilized. Specifically, the primary contact surface of the stop-out plate must be matched to the convex shape of the unexpanded solid cover-plate, and the secondary contact surface must be positioned and sized to properly deform and expand the outer peripheral portions. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.