Abstract:
A lever pivot safety stop socket for fluorescent lamps. The device consists of a molded plastic housing which includes electrical contact strips, attached to power leads; and a plastic, levered and slotted rotor. The rotor fits into an opening in the housing face, leaving its lever portion outside, and able to turn the rotor. Both housing top and lever portion include a wide slot, and when the lever is pointing towards the housing top, the slots line up. This is the lamp installation position, allowing lamp terminal end pins to be easily dropped into the housing slot and into the rotor slots. The lamp can then be rotated a quarter turn in either direction by the lever, to make a full connection with the power contacts in the housing. Provision is made so that no more than a quarter turn can be made from the installation position in either direction, avoiding “opens”, arcing and possible damage. A mounting bracket is attached to the housing for mounting the socket.

Description:
1. FIELD OF THE INVENTION 
   This invention relates to light fixtures for fluorescent lamps, and more particularly to the fixture lamp sockets. 
   2. BACKGROUND 
   At present, conventional fluorescent lamp sockets are designed so that for a lamp installation, it is necessary to first line up the lamp parallel end pins with a central slit in the socket face, push both ends of the lamp all the way into the socket slit and then, holding the lamp, manually rotate the lamp about a quarter turn. The lamp should then be installed. The reverse steps are performed to remove a lamp from the fixture. 
   Problems may arise because a lamp may be rotated more than a quarter turn in a socket during installation. Due to built in tolerances separating the thin insulating components from the curved socket contacts, any over rotation or under rotation can result in only one of the two lamp end pins making electrical contact. Such contact may also be intermittent, particularly if the sockets are old and the contacts have deformed or pitted surfaces. The result is arcing which can damage a lamp as well as a socket, leading to a required removal and replacement of a lamp. 
   This situation is a common problem particularly for small, tubular fluorescent lamps that are installed in closed areas such as display cases. Because of their size and location it is difficult for even a skilled person to see and correctly install or remove a lamp for replacement. The problem is made worse by the fact that a failed lamp in a showcase is likely to be very hot, and so more difficult to grip, rotate and remove. 
   There is therefore, a need for a fluorescent lamp socket that makes installation or removal of a small size lamp easy, and the lamp can not be over or under rotated in a socket. 
   SUMMARY OF THE INVENTION 
   The invention is a lever pivot safety stop socket for fluorescent lamps. The socket consists primarily of a molded rigid plastic housing, that has a wide insertion slot in a the housing top surface, and contains two metal, permanently bent contact strips that are each attached to power leads, and a molded plastic levered rotor. The rotor includes a vertical, wide slot in its front lever portion and a matching axial slot in its perpendicular rotor body that is attached to the lever portion. The rotor body is inserted in a hole in the housing face and retained in the housing with the lever portion positioned with its slot lined up with the insertion slot in the housing top. In this lever position, the end pins of a fluorescent lamps can easily be dropped and inserted in the housing top and into the rotor body, and guided by the lever slot. The lamp can the be rotated, using the socket lever members, a quarter turn in either direction to make a connection with the power contacts in the housing. Provision is made so that no more than a quarter turn can be made from the installation position in either direction. A mounting bracket is attached to the housing for mounting the socket. 
   Accordingly, it is an object of the present invention to improve the ability of removing and replacing lamps. 
   Another object is to ensure that no arcing can take place with an installed lamp and possibly cause damage. 
   Yet another object is to provide a safety stop so that a lamp can not be rotated more than a quarter turn. 
   Further objects and advantages of the present invention will become apparent from a study of the following specification portion, the claims and the attached drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a lever pivot safety stop socket according to the present invention, particularly showing the socket ready for insertion of a fluorescent lamp end pins in a slot through the top of the socket; 
       FIG. 2  is a perspective view of the invention socket, showing the front levered rotor rotated −90 deg. and particularly showing an electrical contact on either side of a center opening in the socket; 
       FIG. 3  is a perspective view of the invention socket, showing the socket, with its front levered rotor rotated +90 deg., and also showing an electrical contact on either side of a center opening; 
       FIG. 4  is a back elevation view of the invention socket, particularly showing a metal mounting bracket riveted to the socket cover; 
       FIG. 5  is a back elevation view of the socket with the cover lid removed, particularly showing electrical leads, with attached contact strips in place; 
       FIG. 6  is a back perspective view of the levered rotor; 
       FIG. 7  is a front elevation view of the levered rotor; 
       FIG. 8A  is a side elevation view of the levered rotor, with its lever arms vertical; 
       FIG. 8B  is a side elevation view of the levered rotor, turned 90 deg., particularly showing a slot opening between two parallel side walls of the rotor body; 
       FIG. 8C  is a partial back view of the rotor body, taken along plane line A—A of  FIG. 8A , particularly showing a slot between two side walls; 
       FIG. 9  is a back elevation view of the socket housing; 
       FIG. 10  is a front elevation view of the socket housing; 
       FIG. 11  is a bottom end view of the socket housing, particularly showing two openings for insertion of the electrical leads with attached contacts; 
       FIG. 12  is a cutaway view of the socket housing taken along line B—B of  FIG. 9 , and particularly showing means for retaining the levered rotor in the housing; 
       FIG. 13  is an elevation view of the cover lid, showing the location of projections for clamping the electrical power leads inside the housing; and 
       FIG. 14  is a side elevation view of the cover lid. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The invention is a lever pivot, safety-stop socket for use with tubular fluorescent lamps, particularly for small size, low wattage lamps. 
   Referring to  FIG. 1 , there is shown a front perspective view of the invention socket and an end part of a fluorescent lamp  1 , with the lamp terminal pins lined up for insertion in an opening that is presented by the socket top end. 
   A slot  7  that is formed in the lever member portion of a rotor  3 , acts as a guide for lamp terminal pins that are inserted in the top opening in the socket housing  5 . The lamp terminal pins are passed through the housing until one pin rests on the lower end of the lever member slot  7  and the lamp end is firmly seated, abutting the rotor  3  on the socket face. 
   As depicted in  FIG. 1 , the position of the rotor  3  is set at zero deg., which is an installation setting that is intended for insertion of a lamp terminal pins. The rotor  3  may be rotated using the lever member, to a −90 deg. position as shown in  FIG. 2 , or rotated to a +90 deg. position as shown in  FIG. 3 . In either the −90 deg. or +90 deg. position, the socket is “locked” or fully closed. The rotor  3  can not be turned more than +/−90 deg. because of straight-edged pads on the lever arm ends  9 , that closely abut the side of the housing  5  when at a +90 deg. or −90 deg. lever rotation angle; blocking further rotation. 
   User operation of the invention socket is simple. The end pins of a tubular fluorescent lamp  1  are first dropped in a top opening in the sockets, and guided by the rotor lever slot  7 , which is initially vertical, into a rotor body slot. 
   Secondly, the fluorescent lamp  1  is manually rotated, using a rotor lever member, in either rotational direction until it stops. A stop will occur at about 90 degrees or a quarter turn. At this point, the lamp is firmly connected to the electric power lines. The user will see that the rotor lever members on both sockets are now pointing horizontally, instead of vertically as at the start. Removal of a lamp is done by reversing the above steps. 
   Electrical power connection is made by having the lamp pins initially wipe spring loaded contact strips over a short distance of the turning arc, before stopping. Thus there is no arcing at connection or disconnection, and electrical connection is always firm and complete. 
   Means described herein, are provided to prevent a socket rotor  3  from being rotated more than a quarter turn and possibly damaging a lamp or socket. 
   Refer now again to  FIG. 1 . Inside the housing  5  are a pair of long, permanently bent, springy brass electrical contact strips  11  that are disposed vertically, one on each side of the rotor  3  body, with a surface bearing against the rotor  3 . The contact strips  11  are each attached to electrical power leads  15  which are brought out a bottom end of the housing  5 . 
   A mounting bracket  13  is provided and is joined to the back cover of the housing  5  by a rivet  17 . The rivet  17  passes through the housing, and holds the cover tightly to the housing walls. 
   It can be seen in  FIG. 1  that no contact strips  11  are visible through the lever slot  7  when the rotor  3  and slot  7  openings are at 0 deg. or vertical. This is because, in this socket “open” position, the contact strips  11  both bear against an outer surface of two parallel walls  27  that define a rotor body opening  26 , inside the housing. Since the rotor slot  7  is fixed to line up with the rotor body opening  26 , the contact strips  11  are kept outside the rotor body walls, and prevented from touching the pins of any inserted fluorescent lamp. 
   Refer now to  FIGS. 2 and 3 . When the rotor  3  is turned either −90 deg. or +90 deg., the contact strips  11  become positioned across the open sides of the rotor body opening  26  and are now exposed. They are then available to wipe and impinge on both lamp pins that may have been inserted earlier and seated in the socket rotor; connecting the electric power leads to the lamp. 
   Please refer to  FIGS. 4 ,  5  and  6 . 
     FIGS. 4 and 5  are respectively a back elevation view and an open back elevation view of the invention socket.  FIG. 6  is a back perspective view of the molded plastic rotor  3  and will help in understanding the following discussion. 
   In the  FIG. 4  view, the rotor  3  lever has been turned a quarter turn, so the lever arm end pads  9  are shown to be abutting a side of the housing  5 . A cover lid  19  fits into the molded housing  5 , and a mounting bracket  13  tang, which fits into a cover recess, is riveted  17  together with the cover lid  19  to the housing  5 . 
   In the open back view of  FIG. 5 , The rotor  3  is in the zero deg. installation position described earlier in  FIG. 1 . For the sake of clarity of understanding, several parts have been exaggerated in size and proportion. The ends of the power leads  15  lie in parallel grooves that are created by surface projections in the housing  5 . Attached to the bare wire end of each power lead  15 , is a spring-flexed contact strip  11  which is inserted under the end disk  22  of the rotor body. The strips are placed between a clamp post  21  and the rotor body, and oriented so that the contact strip surface bears directly on the surface of a rotor body side wall  27 . 
   As shown in  FIG. 5 , when the rotor  3  is in a zero deg. position, the contact strips  11  are essentially paralleled with the rotor lever slot  7  and rotor body opening  26 , and do not face into the body opening  26 . When the rotor  3  is turned a quarter turn, a center portion of each contact strip  11  looks directly into the rotor body opening and is available to contact inserted lamp end pins. 
   The clamp posts  21  are flexible plastic projections that retain a rotor  3  body that is inserted in the housing  5 , by clamping the axial rotor body immediately underneath a body end disk  22 . 
   The rotor  3 , as shown in  FIG. 6 , is an assembly of two molded plastic parts; a lever member and a rotor body which are riveted together. The lever member has a generally flat surface on its inward and face sides, except at the parallel lever arm ends, where the inward side has a sharply stepped block or pad  9 . The pads  9  act as a stopping means, preventing the lever member from being rotated further when the pads are paralleled with a housing side. 
   The rotor body is spool-shaped, and formed of two disks at opposing ends, which are separated by two parallel side walls that are spaced apart, defining an axial body opening slot  26  that extends into a split disk at one end. The body is joined axially at the split disk end to the inward side of the lever member. This rotor body opening slot  26  is made the same width as the housing slot  32  and lever member slot  7 , in order for the lamp end pins to be able to slide into the body slot at lamp installation. 
   In the rotor  3  front elevation view of  FIG. 7 , a slice of the back end disk  22  of the rotor body is visible through the slot  7  in the lever member, because the rotor body opening  26  width matches the width of the slot  7  and is aligned with it. 
   A curved cut-out  25  is made in opposite edges of the lever member, to match a center opening  32  in the top of the housing  5  when the lever member is rotated 90 deg. in either direction. Two rivet holes for fastening the rotor are shown. 
     FIGS. 8A ,  8 B and  8 C, serve to further illustrate and emphasize the particular structure of the rotor body in the rotor assembly. This feature plus the lever member slot and stops embody the core of the invention. 
     FIG. 8A  is a side elevation view of the rotor  3  in a zero deg. position, with the lever member arms pointing upwards. In this view, the body opening  26  is hidden by a side wall  27 . 
   In  FIG. 8B , the rotor  3  has been turned 90 deg. and the body opening  26  is fully visible between the side walls  27 ; appearing as it would be, to a contact strip inside the housing. If a lamp terminal pins were seated in the rotor lever slot  7  and body opening  26 , a contact strip would bear against a pin on both sides. 
     FIG. 8C  is cross-section view of the rotor body taken along line A—A of  FIG. 8A . In this view, the body opening  26  is seen to extend into, and split an end desk, which is joined to the lever member and thus appears as shown in  FIG. 7 . 
     FIGS. 9 and 10  are respectively, a back elevation view of an uncovered housing  5 , and a front elevation view of the housing  5 . A large circular first opening  30  is cut in the housing face  4  and sized to permit insertion of the rotor  3  body in assembly of the socket. Starting at the top of the first opening  30 , is a second opening  32  which is a slot that continues across the top of the housing. It is this housing opening that is used for insertion of the fluorescent lamp end pins. 
   The top slot opening  32  continuation is shown in  FIG. 12 , which is a cross-section view, looking toward the housing top, taken along line B—B of  FIG. 9 . 
   A third opening  36  in the housing face is made for riveting the housing to the cover and mounting bracket. 
   The tops of the clamp posts  21  that are used to retain the rotor body inside the housing, are indicated in  FIGS. 9 and 10 , and a side view of the posts  21  is given in  FIG. 12 . The posts  21  are flexible but springy plastic. When the rotor body is pushed through the first opening  30  in the housing face, the posts are initially flexed outwards by the body end disk  22 , to let the end disk  22  pass through. The posts  21  then snap back under the end disk  22 , clamping the rotor body lightly; preventing withdrawal of the rotor body from the housing  5 . 
   At the bottom, open end of the housing are located three raised blocks; two side blocks  38  and a central block  34 . These three blocks define two channels in which the ends of the power leads  15  are placed.  FIG. 11 , which is a bottom end view of the housing, indicates the channel openings  40  created by the blocked portions. The blocked portions also serve to support the cover lid  19 , so that when the cover lid  19  is riveted on the housing, it clamps down on the power leads  15 . 
     FIGS. 13 and 14  are respectively, an inside face elevation view and a side elevation view of the cover lid  19 . The cover lid includes four horizontally extending, rigid fingers  44  and a fourth opening  42 . When the cover lid  19  is riveted in place to the housing, the fingers  44  act as guides for the wire ends of the power leads  15  and also hold them in place, preventing the leads from being pulled out of the socket housing. 
   As described in the foregoing, the socket is constructed of few parts, and is primarily composed of a molded plastic housing and cover; a molded plastic rotor assembly; a pair of metal electrical contact strips to which power leads are attached, and a mounting bracket for mounting the socket in any direction. The invention socket is thus a simple device that is economical to produce. 
   The levered socket inherent characteristics ensure that only a complete full electrical contact can be made with inserted lamp terminals, every time the socket lever member is rotated a quarter turn from the lever member lamp installation position. There is therefore, no possibility of only one of two lamp terminal pins making proper electrical contact, such as sometimes occurs with conventional sockets, resulting in possible damage to the lamp. 
   An advantage over conventional sockets, is that power to an installed fluorescent lamp can be switched off by the socket before removal and replacement of a lamp. This aspect would be much appreciated by anyone who has to remove and replace a hot fluorescent lamp that is installed in a showcase. 
   Finally, the invention socket design, obviously makes it easy for any unskilled person to install or remove a tubular fluorescent lamp correctly every time, regardless of a lamp size, or the location of the sockets. 
   From the foregoing description, it is believed that the preferred embodiment achieves the objects of the present invention. Alternative embodiments and modifications will be apparent to those skilled in the art. These and other modifications are considered to be equivalent and within the spirit and scope of the present invention.