Abstract:
A socket bulb includes a shell inside which a depression device, a clamp device, and conductive plates are arranged. The shell has a lower opening through which the base of a bulb can be put into the shell in a linear movement. Depression operation of the depression device by the base of the bulb moves the clamp device to move between a raised position and a lowered position. When the clamp device is moved from the raised position to the lowered position, the bulb is securely retained inside the shell in electrical engagement with the conductive plates through which power is supplied to the bulb. When the clamp device is moved from the lowered position to the raised position, the bulb is released and can be withdrawn easily. As such, an efficient and safe structure for mounting and dismounting a bulb in a socket is provided.

Description:
BACKGROUND OF THE INVENTION  
   (a) Technical Field of the Invention 
   The present invention relates generally to a bulb socket, and in particular to a depression-to-release bulb socket, which allows mounting and dismounting of a bulb to be realized by a single depression of the bulb. 
   (b) Description of the Prior Art 
   A conventional lamp bulb comprises a bulb made of for example glass and having a lower end to which a base made of copper alloy and forming a threaded ring contact and a tip contact is mounted. A filament is arranged inside the bulb and is connected to two wires for supplying power to the filament. One of the wires extends out of the bulb and is attached to the ring contact of the base and the other wire is attached to the tip contact to respectively serve as negative and positive electrodes of the lamp bulb. A conventional bulb socket is constructed to receive the lamp bulb therein, comprising an insulation shell in which a conductive and threaded inner shell and a resilient conductive contact are arranged. The inner shell and the resilient contact of the socket are respectively connected to negative and positive terminals of a power source. 
   The bulb is received in socket in a threading manner by relative rotation therebetween in order to make the ring contact of the bulb engaging the inner shell of the socket and the tip contact of the bulb engaging the resilient contact of the socket. Thus, power can supplied from the external power source through the socket to the bulb. To remove the bulb from the socket, the bulb is rotated in a reversed direction to disengage the ring contact of the bulb from the inner shell of the socket. 
   The conventional threading type bulb and bulb socket, although effective in securing electrical engagement between the bulb and socket and allowing removal of the bulb from the socket, yet suffers the following disadvantages: 
   (1) The bulb must be rotated three or four full turns in order to securely fix in the socket and establish electrical engagement therebetween or to completely remove the bulb from the socket. This operation is time-consuming and inefficient. 
   (2) In rotating the bulb to detach the bulb from the socket, it is difficult to very precisely predict when the bulb is completely disengaged from the socket. Further, in doing the rotation, a user&#39;s hand, which cannot do a full turn, must repeatedly release and re-hold the bulb. With ignorance of the exact time when the bulb is disengaged from the socket, each time the user&#39;s release and re-hold the bulb in order to proceed with the next turn of rotation, it is always a serious concern of the user if the bulb will happen to disengage from the socket and falls when the user&#39;s hand just release the bulb. This is especially true is dismounting a large and heavy bulb and especially for a female user, who is usually weak with her hand&#39;s muscles. It is due to this reason that some female users still consider changing bulbs very difficult. 
   (3) If the glass bulb is broken, to remove the broken bulb from the bulb socket is an even more tough job, for the user cannot but to grip the broken glass or to grip a very tiny portion of the ring contact of the broken bulb that is exposed outside the socket and this often injure the user by being cut by the broken glass. Alternatively, a hand tool must be used to grip the base of the broken bulb in order to apply torque to the bulb. This is certainly troublesome and dangerous. 
   Thus, it is desired to have a bulb socket to allow an existing bulb having a threaded base to be secured and released in a more efficient and safer manner. 
   SUMMARY OF THE INVENTION  
   The primary purpose of the present invention is to provide a bulb socket, which allow a bulb to be secured therein or removed therefrom by a single operation of depressing the bulb so that mounting and removal of the bulb can be carried out in an efficient and safe manner. 
   To achieve the above objective, in accordance with the present invention, there is provided a depression-to-release bulb socket, comprising: a shell defining an interior space delimited by a circumferential side wall and having an open end for entry and receipt of a base of a bulb in the interior space, a stepped flange being provided on an inside surface of the side wall at a location close to the open end, the stepped flange having a converged cross-sectional dimension as compared to the side wall of the shell; a depression device comprising a pushbutton arranged in the interior space of the shell and movable between a first position and a second position by a depression operation; a clamp device mounted to the pushbutton to be movable in unison therewith and having a circumference received in the interior space and a plurality of clamping fingers extending from the circumference in a direction toward the open end of the shell, each clamping finger forming on an inside face thereof at least one catch; and conductive plates arranged inside the shell and having first and second vertical sections respectively, which have lower ends engageable with a ring contact and a tip contact of the base of the bulb when the bulb is received in the shell. 
   In accordance with the depression-to-release bulb socket of the present invention, by initiating the depression operation of the pushbutton by the base of the bulb in the shell, the pushbutton drives the clamp device between a raised position and a lowered position and releasably retained at the positions. When the clamp device is moved from the raised position to the lowered position, the bulb is retained in a position inside the socket for electrical engagement with the conductive plates and when the clamp device is moved from the lowered position to the raised position, the bulb is allowed to easily withdraw out of the socket. Thus, an efficient and safe structure for mounting and dismounting a bulb in a socket is provided. 
   The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
   Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a bulb socket constructed in accordance with the present invention, with a bulb to be mounted thereto being shown as well; 
       FIG. 2  is an exploded view of the bulb socket of the present invention, a shell of the socket being partially broken to show inside details; 
       FIG. 3  is a cross-sectional view of the bulb socket of the present invention; 
       FIG. 4  is a cross-sectional view of the bulb socket of the present invention into which a bulb is being inserted, but not reaching a completely retained position; 
       FIG. 5  is similar to  FIG. 4  with the bulb secured in a completely retained position; 
       FIG. 6  is another cross-sectional view of  FIG. 4  showing electrical connection of the bulb with wires that lead to an external power source; 
       FIG. 7  is a cross-sectional view similar to  FIG. 5  but showing another embodiment of the bulb socket of the present invention; and 
       FIG. 8  is a cross-sectional view similar to  FIG. 5  but showing a further embodiment of the bulb socket of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
   With reference to the drawings, and in particular to  FIGS. 1 ,  2 , and  3 , a bulb socket constructed in accordance with a first embodiment of the present invention comprises a shell  10  inside which a depression device  20 , a clamp device  30 , and conductive plates  40  are mounted. 
   The shell  10  has an open end, which is the lower end as shown in the drawings, but can be put upside down and become the upper end, and an opposite closed end, which is the upper end in the drawings, but can be put upside down and become the lower end. The open end is provided for the entry and receipt of a conductive base  51  of an existing threading type bulb  50  in a linear movement, not rotational movement. A stepped flange  11  is formed in an inside surface of the shell  10  and close to the open end with a converged cross-sectional dimension. A chamber  12  is formed inside the shell  10  and extends inward from the closed end and forming an open end to movably receive the depression device  20  therein. Through holes  13  are defined in the closed end of the shell  10  and preferably on opposite sides of the chamber  12  for the extension of electrical wires  60  therethrough, respectively. 
   The depression device  20  comprises a shank-like pushbutton  21  movably received in the chamber  12  so that the pushbutton  21  is linearly and axially movable with respect to the chamber  12 . The pushbutton  21  is sized to ensure a snugly engagement with the side wall of the chamber  12  for guiding linear movement thereof. A free end of the pushbutton  21  projects beyond the lower open end of the chamber  12  to be engageable by the bulb  50  for applying an actuation force thereto. The pushbutton  21  is axially movable between a first position (or a raised position) where the pushbutton  21  is received more in the chamber  12  with a smaller portion projecting beyond the chamber  12  and a second position (or a lowered position) where the pushbutton  21  is received less in the chamber  12  with a larger portion projecting beyond the chamber  12 . 
   Movement of the pushbutton  21  is realized by providing multiple pairs of ribs (not labeled) of a predetermined length on an inside surface of the side wall of the chamber  12  of the shell  10  and spaced in a circumferential direction, preferably in equally spaced manner. Each pair of ribs delimits a slot therebetween, serving a guide rail  14 . The pushbutton  21  has an outer circumferential surface on which axially extending projections  22 , serving as slides movably received in the guide rail  14 , are formed. A positioner  23  is mounted to a top end of the pushbutton  21  in a rotatable manner and located inside the chamber  12 . A spring  25  is arranged between a top end of the positioner  23  and an inner closed end of the chamber  12 , but it is apparent that other resilient member can be used instead of the spring  25 . 
   Referring to  FIGS. 3 and 4 , when the pushbutton  21  is forcibly moved toward the raised position and then released, the positioner  23  is moved to such a location that sideway extending pawls  24  formed on a circumference of the positioner  23  engages top ends of the ribs that form the guide rails  14 , respectively, and are thus retained in position by the top ends of the ribs. Referring to  FIG. 5 , when the pushbutton  21  is forcibly moved inward again, the pawls  24  are moved to locations corresponding to spacing between the rails  14 , and the pushbutton  21  is forced by the biasing force of the spring  25  to move downward to the lowered position. 
   The clamp device  30  is mounted to a lower end of the pushbutton  21  and is movable in unison with the pushbutton  21 . The clamp device  30  comprises a flat body fixed to the pushbutton  21  and an outer circumference substantially corresponding to an interior space of the shell  10 . Clamping fingers  31  extend from the outer circumference of the clamp device  30  in a downward direction and each clamping finger  31  has a lower end forming on an inside face thereof inward projections  32 , serving as catches. When the pushbutton  21  and the clamp device  30  are located in the raised position, the lower end of the fingers  31  are positioned at a location above the stepped flange  11  of the shell  10  so that the fingers  31  are in an outward expanded condition to allow easy entry of the base  51  of the bulb into the shell  10  in a linear movement. When the pushbutton and the clamp device  30  are in the lowered position, the lower end of the fingers  31  are inward deflected by the stepped flange  11  so that the catches  32  are forced inward to engage the threading of the base  51  of the bulb  50  thereby securing the bulb  50  in the shell  10 . 
   Referring to  FIGS. 2 ,  3 , and  6 , the conductive plates  40  are arranged inside the shell  10  at locations corresponding to the through holes  13  and are made in electrical connection with the wires  60 . Each conductive plate  40  has a vertical section  41 ,  42  positioned against and fixed to the inside surface of the shell  10 . The first vertical section  41  of the first conductive plate  40  has an inclined lower section that extends into the interior space of the shell  10  to such a location that a free end thereof is engageable with a ring contact portion of the base  51  of the bulb  50  when the bulb  50  is received in the socket. The second vertical section  42  of the second conductive plate  40  has a lower end that is bent so as to have a free end thereof located exactly below the pushbutton  21  for engagement with a top contact of the base  51  of the bulb  50  when the bulb  50  is inserted in to the shell  10 . This arrangement also allows the tip contact of the bulb  50  to apply an inward pushing force to the pushbutton  21  through the free end of the second conductive plate  40 . 
   With the pushbutton  21  and the clamp device  30  located at the raised position, to mount the bulb  50  in the socket, the base  51  of the bulb  50  is inserted through the open end into the shell  10  and a force is applied through the bulb  50  to the pushbutton  21  to force the pushbutton  21  and the clamp device  30  inward. The force is then removed to release the bulb, whereby, with the pawls  24  disengaging from the top ends of the rails  14 , the pushbutton  21  and the clamp device  30 , together with the base  51  of the bulb  50 , are biased by the spring  25  to the lowered position where the catches  32  of the clamping finger  31 , by being inward deflected by the stepped flange  11 , engage threading of the base  51  of the bulb  50  and thus secure the bulb  50  in position and ensure electrical engagement between the base  51  of the bulb  50  and the conductive plates  40 . To remove the bulb  50  from the socket, the bulb  50  is pushed inward into the shell  10  to have the pawls  24  of the positioner  23  engage the top ends of the rails  14  again, which maintains the pushbutton  23  and the clamp device  30  in the raised position, where the fingers  31  are moved back to the expanded condition to allow easy withdrawal of the base  51  of the bulb  50  out of the shell  10 . 
   Referring to  FIGS. 2 and 3 , preferably, guide rails  15  are formed on the inside surface of the shell  10  for respectively and movably receiving the clamping fingers  31  therein. This ensures stability and proper positioning of the clamping fingers  31  during the movement thereof with the pushbutton  21  between the raised position and the lowered position. 
   With reference to  FIG. 7 , an external threading  16  is selectively formed on an outer surface of the shell  10  for engagement with and coupling to a connection device  17 , which can be for example a cap of the socket. Also, venting holes  18  are formed in the side wall of the shell  10  for air circulation and heat dissipation. 
   Further, although multiple catches  32  that are formed for engaging threading of a bulb are demonstrated in the previous embodiments, a single projection can be formed on the lower end of each clamping finger  31  to serve as the catch and all the single projections are of substantially the same altitude. This allows the catches of the clamping fingers  31  to precisely and snugly engage a circumferentially-extending groove  53  defined in a base  51  of a horizontally-grooved bulb, and the present invention can be further applicable to the horizontally-grooved bulb. 
   Referring to  FIG. 8 , the conductive plates  40  can be arranged in such a manner that the first and second vertical sections  41 ,  42  are fixed on the inside surface of the shell  10  at locations corresponding to the through holes  31  of the shell  10  and in electrical connection with the wires  60  and that the first vertical section  41  has a free end engageable with the ring contact of the base  51  of a bulb fit into the socket and the second vertical section  42  is not engageable with the base  51  of the bulb. A conductive cross member  43  is mounted to the underside of the pushbutton  21  and is engageable with the tip contact of the base  51  of the bulb. When the pushbutton  21  is moved to the raised position, the cross member  43  is brought into engagement with the second vertical section  42  of the conductive plate  40  and when the pushbutton  21  is moved back to the lowered position, the engagement between the cross member  43  and the second vertical section  42  of the conductive plate  40  is broken. This enhances operation safety for power can only be supplied when the bulb is properly installed. Power cannot be supplied before the bulb is properly secured and thus heating of the bulb during an incomplete installation process is prevented from occurring and the user&#39;s hand is protected from being burnt or discomfort caused by the heating. 
   Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. For example, the depression device  20  can be replaced with any known depression-to-release/secure means, while still effecting the same function of securing and releasing a bulb in the socket of the present invention by depression and movement of the bulb between a raised position and a lowered position. 
   It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
   While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.