Patent Publication Number: US-6666701-B1

Title: Bayonet-type electrical connector assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to electrical connectors and, more particularly, to bayonet-type electrical connectors assemblies. 
     BACKGROUND OF THE INVENTION 
     The need to provide electrical contact between detachable components is well known. Electrical connectors employed for such a purpose commonly include two connector halves held by a connector nut. Such connectors have been used in many applications, such as providing a contact between a detachable sensor and an electronics housing. Detachable sensor assemblies are used in a variety of industrial applications, many exposing the sensor assembly to harsh environments, e.g., substantial vibrations, fluids and excessive contact force. 
     Such industrial applications have proven to induce malfunctions in prior connector assemblies. For example, excessive vibrations can dislodge the connector halves from one another, i.e., axial separation, causing a break in electrical contact. Also, repeated coupling and uncoupling of electrical connector halves, such as those using pin-type connectors, can cause damage to the connectors, particularly, where inadequate care is taken by maintenance personnel. Thus, it is beneficial to provide an electrical connection that not only establishes a reliable electrical connection but also establishes a sturdy mechanical connection of the connector halves. 
     It should, therefore, be appreciated that there is a need for a bayonet-type connector assembly that provides a rugged and reliable mechanism for releasably securing a first connector half to a second connector half, useable in a variety of applications such as securing a detachable sensor to an electronic housing. The present invention fulfills this need as well as others. 
     SUMMARY OF THE INVENTION 
     The present invention provides a bayonet-type connector assembly for releasably securing a first connector half to a second connector half along a connection axis by simple rotation of a bayonet nut. Each connector half includes a plurality of electrical contacts. The bayonet nut encircles the second connector half. Rotation of the nut to a closed position causes a thread segment on the nut to engage a corresponding grooved segment of the first connector half, to mate the connector halves, enabling electrical contact between the connector halves. Rotation of the bayonet nut also slides a slidable portion, i.e., a nut cam, beneath a cam of the second connector half to prevent axial separation of the two connector halves. The connector assembly further includes a detent positioned to engage a securement on one of the cams to releasably lock the nut in the closed position. The connector assembly is particularly effective in applications where a risk of inadvertent axial separation of connector halves exists. Moreover, all of the parts can be manufactured by simple, relatively inexpensive injection molding techniques. 
     In a detailed aspect of preferred embodiments of the invention, the second connector half further includes a second cam disposed adjacent to the opening of the cavity. The second cam is oriented generally perpendicular to the connection axis and is spaced apart from the first cam of the second connector half. The nut further includes a second cam configured to cooperate with the second cam of the second connector half, to prevent axial separation of the connector halves. The nut further has an open position within 70 degrees of rotation from the closed position for receiving the first connector half. Thus, the nut inhibits connecting the electrical contacts of the first and second connector halves without rotating the nut from the open position to the closed position. 
     In another detailed aspect of preferred embodiments of the invention, the electrical contacts of the second connector half are pogo-style pin contacts and the electrical contacts of the first connector are planar contacts oriented perpendicular to the contacts of the second connector. The spring forces of the pogo-style pins aid in maintaining a positive connection between the contacts. 
     In yet another detailed aspect of a preferred embodiment of the invention, the detent is a deflectable finger positioned adjacent to a trailing edge of the cam of the second connector half and the securement is a depression defined by the cam of the nut adjacent to a trailing edge thereof. 
     In a preferred embodiment of the invention, the first connector half includes an O-ring mounted to contact the second connector half within the cavity and to provide a fluid-resistant seal. 
    
    
     Other features and advantages of the invention should become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which: 
     FIG. 1 is an exploded perspective view of a preferred embodiment of a bayonet-type connector assembly in accordance with the invention, the connector assembly including a first connector half, a second connector half, and a bayonet nut; 
     FIG. 2 is an elevational view of an electrical housing and detachable sensor incorporating the connector assembly of FIG. 1; 
     FIG. 3 is a perspective view of the first connector half of the connector assembly of FIG. 1; 
     FIG. 4 is a perspective view of the second connector half of the connector assembly of FIG. 1; 
     FIG. 5 is a plan view of the bayonet nut of the connector assembly of FIG. 1; and 
     FIG. 6 is a perspective view of the bayonet nut of the connector assembly of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the illustrative drawings, and particularly to FIG. 1, there is shown a bayonet-type connector assembly  10  having a first connector half  12 , a second connector half  14 , and a bayonet nut  16 . The first and second connector halves include electrical contacts  18  (FIG.  3 ),  20 , respectively. The bayonet nut encircles the second connector half. Rotation of the nut to a closed position causes two short thread segments  22  on the nut to engage corresponding grooved segments  24  formed in the first connector half, to mate the connector halves along a connection axis (A—A), enabling electrical contact between the connector halves. Rotation of the bayonet nut also slides two slidable portions, i.e., nut cams  26 , beneath a corresponding pair of cams  28  of the second connector half. This prevents axial separation of the two connector halves. The connector assembly further includes detents, i.e., deflectable fingers  30 , each positioned to engage a corresponding depression  32  (FIG. 5) formed by the nut cams. Once engaged, the detents releasably lock the nut in its closed position. The connector assembly is particularly effective in applications where a risk of inadvertent axial separation of connector halves exists. Moreover, all of the parts can be manufactured by simple, relatively inexpensive injection molding techniques, and the connector assembly provides additional safety-related and economic benefits, as will be described below. 
     With reference to FIG. 2, the connector assembly  10  is shown beneficially employed in securing a detachable sensor  34  to an electronics housing  36 . In this embodiment, the second connector half  14  is positioned at a bottom portion of the electronics housing and the first connector half  12  is positioned at an upper portion of the sensor (not shown). The connector assembly provides a sturdy mechanical connection of the connector halves, thereby minimizing the risk that excessive vibrations will dislodge the connector halves from one another, causing a break in electrical contact. Moreover, the connector assembly provides a smooth mating action of the connector halves, minimizing the risk of damage to the contacts  18 ,  20 , even where appropriate care is not taken by maintenance personnel. The first connector half includes an O-ring  38  (FIG. 3) positioned to form a fluid-resistant seal with the second connector half, thereby reducing a risk of fluid exposure at the interface of the connector halves. Thus, the connector assembly provides reliable electrical and mechanical connections, even in harsh environments. 
     With reference to FIG. 3, the first connector half  12  is generally cylindrical and has six electrical contacts  18 . Each contact is positioned within a contact recess  40  and terminates in a relatively small circular plate positioned atop a post  42  within the corresponding contract recess. The contact recesses are configured cooperate with the second connector half  14  to allow contact between the electrical contacts  18 ,  20 . The O-ring  38  is positioned within a channel  44  encircling an upper portion  46  of the first connector half. It provides a fluid-resistant seal within the cavity of the second connector half, once mated. The grooved segments  24  are positioned below the O-ring with respect to the six contacts. 
     With reference now to FIG. 4, the second connector half  14  is generally cylindrical and defines a cavity  48  having an opening  50 . The cavity is configured to receive the upper portion  46  (FIG. 3) of the first connector half  12 . The cams  28  of the second connector half are generally arc-shaped, outwardly cantilevered ledges extending from upstanding portions  52  and are positioned on opposite sides of the cavity opening, generally perpendicular to the connection axis (A—A). The cams of the second connector half and an upper surface  54  define recesses  56  for receiving the nut cams  30 . When the nut  16  is rotated to its closed position, the nut cams slide into the recesses  56 , clamping the nut to the second connector half. In the closed position, the cams inhibit axial separation of the connector halves. Although in this embodiment the cams are configured as cantilevered ledges, it will be appreciated that they can have alternate configurations without departing from the invention, so long as the cams cooperate to prevent axial separation of the connector halves. 
     The deflectable fingers  30  are adjacent to the cams  28  of the second connector half Each deflectable finger extends from the upper surface  54  and defines a lower curved portion  58 . The curved portions are configured to be securely received by the corresponding depressions  32  (FIG. 5) of the nut  16 . Once the nut has been rotated to the closed position, the curved portions are disposed within the depressions, securing the nut in the closed position. The fingers and the depressions are configured to maintain the nut in the closed position in the face of various forces, e.g., equipment vibration and incidental contact. 
     The electrical contacts  20  of second connector half  14  are configured as six spring-loaded connector pins, i.e., pogo-style pins, and are each located within a protective support  60  disposed within the cavity  48 . The protective supports are cylindrical, each encircling a corresponding pogo-style pin and extending above the height of the pin. The protective supports are sized and aligned to be received within contact recesses  40  (FIG. 3) defined in the first connector half  12 . The spring forces of the pogo-style pins aid in providing positive contact pressure between the electrical contacts  18 ,  20  of the connector halves, ensuring electrical contact. 
     With continued reference to FIG. 4, the second connector half  14  further includes a circular rib  62  extended around its outer periphery. The rib enables a snap fit with the bayonet nut  16  as described further below. The second connector half also includes a stepped portion  64  positioned below the rib with respect to the opening  50 . The stepped portion provides a smooth and aesthetic transition between the second connector half and the bayonet nut, as shown in FIG.  2 . 
     With reference now to FIGS. 5 and 6, the bayonet nut  16  includes an inner cylinder  66  and an outer grip  68  encircling the inner cylinder. The inner cylinder is configured to allow the first connector half to extend through and mate with the second connector half, once the nut is in its closed position. The thread segments  22  are positioned on the inner surface of the cylinder to engage the grooved segment  24  of the first connector half. The thread segments and the grooved segments cooperatively provide about 70 degrees of rotation from an open position for receiving the first connector half to the closed position. 
     The nut cams  26  are positioned between the inner cylinder  66  and the outer grip  68  and are oriented generally parallel to the cams  28  of the second connector half  14 . The nut cams cooperate with the cams of the second connector half to prevent axial separation of the connector halves when the nut is in its closed position. The nut cams are configured as arc-shaped ledges inwardly cantilevered from the outer grip. In the open position, the nut cams sit next to the cams of the second connector half. In use, the operator rotates the nut from the open to the closed position, causing the nut cams to slide beneath the cams of the second connector half, interlocking the two sets of cams. Once the closed position is reached, the detents  30  are releasably locked within the depressions  32  and the cams of the second connector half sit next to walls  70 . Each depression is located on a slidable surface  72  adjacent to a leading edge  74  of its respective nut cam. 
     With continued reference to FIGS. 5 and 6, the bayonet nut  16  includes a circular recess  76  configured to cooperate with the circular rib  62  of second connector half  12  for attaching the nut to the second connector half. The circular recess receives the rib by axially snapping the nut onto the first connector half. This snap fit allows rotation of the nut between its open and closed positions, while maintaining the nut&#39;s axial relationship with the housing. When snapping the nut to the housing, the nut cams  26  and the cams  28  of the second connector half must be properly aligned. The nut cams are sufficiently spaced within the region between the cylinder  66  the outer grip  68  to allow the cams of the second connector half to extend therein. 
     It should be appreciated from the foregoing description that the present invention provides a connector assembly with a rugged and reliable mechanism for releasably securing a first connector half to a second connector half, by rotation of a bayonet nut. The connector assembly is particularly effective in applications where a risk of inadvertent axial separation of connector halves exists. Moreover, the connector assembly is cost-effective to manufacture, operate and maintain. 
     The foregoing detailed description of the present invention is provided for the purposes of illustration and is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Accordingly, the scope of the present invention is defined by the following claims.