Abstract:
A collapsible mount for mounting an electronic device to a circuit board includes a base adapted to be fixed to the circuit board and two support arms each having a lower end pivotably connected to the base and spaced from each other so as to be rotatable with respect to the base between a stowed position and an expanded position wherein the two support arms are substantially opposite to each other to define a space therebetween adapted to accommodate the electronic device therein.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a circuit board mount for mounting/connecting a circuit board or a CPU module to a main computer board and in particular to a collapsible circuit board mount which reduces the space occupied thereby at a stowed position. 
     2. The Prior Art 
     A connection device is commonly used to mount and connect a circuit board or an electronic component to a main computer board. Taking a central processing unit (CPU) of a computer as an example, the CPU is conventionally fixed to the main board by being directly soldered thereto. Nowadays, however, the CPU is first fixed to a circuit board to form a CPU module which is then mounted to the main board by means of a connection device. This helps to reduce the occupied space on the main board. The circuit board that is mounted to the main board by means of the connection device must be firmly supported by support means otherwise the circuit board that is usually perpendicular to the main board may shake or vibrate. Thus, a poor connection between the circuit board and the connection device may result thereby causing malfunction of the computer or the parts thereof. 
     Support means directly fixed on the connection device as a unitary member for retaining the circuit board on the connection device is disclosed in Taiwan Patent Application Nos. 85216861, 85216815, 85215723 and 85216150 and U.S. Pat. No. 3,993,390, 4,057,879, 5,207,598, 5,259,793 and 5,429,523, while in U.S. Pat. Nos. 2,825,037 and 3,829,741, support means that is separate from and additionally mounted to the connection device to support the circuit board is disclosed. Both types of support means have a common disadvantage that the support means constitutes an elongate support arm member that is generally not movable or collapsible with respect to the connection device thereby occupying a significant amount of space which is inconvenient for packing and transportation of the connection device. 
     In addition, the connection device of this type is usually mounted to the main board with fixing means having a complicated structure which makes manufacture laborious thereby increasing costs. 
     It is thus desirable to have a collapsible circuit board mount for connecting and mounting a circuit board to a main computer board that overcomes the problems encountered in the prior art. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a circuit board mount which has two collapsible support arms that are rotatable with respect to a mount base so as to reduce the overall dimension of the mount at a stowed position. 
     Another object of the present invention to is provide a collapsible mount wherein a ratchet and paw system is incorporated between a base and support arms so as to selectively retain the support arms at an expanded position. 
     A further object of the present invention is to provide a collapsible mount wherein pivot pins are provided on a base to be rotatably received in holes defined in the support arms, the pivot pins having an inclined free end for facilitating insertion of the pivot pin into the respective hole of the support arm. 
     Still another object of the present invention is to provide a collapsible mount wherein a mount base comprises a plurality of fixing members for fixing the base to the main board, the fixing members having a simple structure thereby simplifying the manufacture thereof and reducing costs. 
     In accordance with an aspect of the present invention, a collapsible mount adapted to mount/connect an electronic device, such as a CPU module or a circuit board, to a main board, comprises a base fixed on the main board and two support arms pivotably connected to the base to be movable between a stowed position and an expanded position wherein the support arms are substantially opposite and spaced from each other to accommodate the electronic device therebetween. A positioning device is provided to retain the support arms at the expanded position. 
     The positioning device comprises a ratchet wheel formed on the base and having two spaced teeth respectively corresponding to the expanded position and the stowed position and a corresponding paw which is provided on the support arm to be movable therewith for selectively engaging one of the teeth of the ratchet wheel to position and retain the support arm at either the stowed position or the expanded position. 
     In accordance with another aspect of the present invention, the pivotal connection between each support arm and the base comprises two pivot pins extending from two sides of the base and two corresponding holes defined in each support arm for receiving the pivot pins therein. The pivot pins have an inclined free end which facilitates insertion of the pivot pins into the respective holes of the support arms. 
     In accordance with a further aspect of the present invention, the base of the collapsible mount comprises a plurality of channel members attached to the two sides thereof, each receiving an inner-threaded cylinder. A bore is defined in each channel member to be aligned with the inner-threaded cylinder for receiving a fastener therethrough for fixing the mount to the main board. Each channel member has two side walls each forming a triangular pawl opposite each other and defining a neck therebetween. The channel member further comprises an end wall having a pawl opposite the neck so as to retain an expanded bottom of the inner-threaded cylinder in the channel member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the accompanying drawings, in which: 
     FIG. 1 exploded perspective view of a collapsible mount constructed in accordance with the present invention for mounting a circuit board or an electronic device to a computer main board; 
     FIG. 2A is a front view of a support arm of the collapsible mount; 
     FIG. 2B is a side view of FIG. 2A; 
     FIG. 2C is a cross-sectional view of FIG. 2A; 
     FIG. 3A is a top plan view of a mount base of the collapsible mount; 
     FIG. 3B is a side view of FIG. 3A; 
     FIGS. 4B and 4C are sequential cross-sectional views of a portion of the support arm and the mount base, showing the pivotal connection therebetween; 
     FIG. 5A is a top plan view of a fixing device of the collapsible mount; 
     FIG. 5B is a cross-sectional view of the fixing device; 
     FIG. 6 is a side elevational view of the collapsible mount at an expanded position; 
     FIG. 7 is a side elevational view of the collapsible mount showing the support arms thereof at a stowed position; 
     FIG. 8A is a partial cross-sectional view of a positioning device of the collapsible mount at the expanded position; and 
     FIG. 8B is a partially cross-sectional view of the positioning device of the collapsible mount at the stowed position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the drawings and in particular to FIG. 1, a collapsible circuit board mount  1  constructed in accordance with the present invention comprises a mount base  11  adapted to be fixed to a main board (not shown). The mount base  11  has two opposite ends each having a support arm  10  pivotably attached thereto by means of a collapsing mechanism  12 . 
     Further referring to FIGS. 2A,  2 B and  2 C, the support arm  10  comprises an elongate body defining a channel  101  between two side walls  100  thereof for receiving and retaining an edge of a circuit board (not shown) to be mounted to the main board. A notch  102  is defined in each of the two side walls  100  at a first end of the support arm  10 . Each of the side walls of the support arm  10  has a second end pivotably attached to the mount base  11  by means of the associated collapsing mechanism  12  thereby allowing the support arm  10  to be rotatable with respect to the mount base  11  between an expanded position (FIG. 6) and a stowed position (FIG.  7 ). 
     With further reference to FIGS. 3A and 3B, the mount base  11  comprises an elongate body defining a slot  110  therealong between two side walls  115  thereof for receiving a connector (not shown) fixed on the main board thereby fixing the circuit board mount  1  to the main board. 
     The collapsing mechanism  12  comprises two pivot pins  121  provided at each of two opposite ends of the elongate body of the mount base  11  and extending in opposite directions from the two side walls  115  of the mount base  11  to be substantially aligned with each other. The pivot pins  121  are respectively received in two corresponding holes  122  defined in the two side walls  100  of the respective support arm  10  at the second end thereof thereby forming a pivotal connection between the second end of the support arm  10  and the mount base  11 . 
     As particularly shown in FIGS. 4A,  4 B and  4 C, each of the pivot pins  121  of the mount base  11  comprises an inclined free end  1211  which facilitates the engagement of the pivot pin  121  into the corresponding hole  122  on the respective support arm  10 . Preferably, a chamfer  100  is provided on the second end of the support arm  10  to cooperate with the inclined free end  1211  of the pivot pin  121  so as to further facilitate the insertion of the pivot pin  121  into the corresponding hole  122  on the support arm  10 . 
     The support arm  10  also comprises retaining means  13  which retains the support arm  10  at the expanded position. The retaining means  13  comprises a first projection  131  formed on each of the side walls  100  of the support arm  10  and engageable with a second projection  130  formed on the side wall  115  of the mount base  11 . The projections  131 ,  130  are shaped and positioned in such a way that when the support arm  10  is moved from the stowed position toward the expanded position, the first projection  131  of the support arm  10  is brought into engagement with the second projection  130  of the mount base  11  and a further rotation of the support arm  10  causes a deformation on each of the projections  130 ,  131  to allow the first projection  131  to slide over the second projection  130  thereby forming a tight engagement therebetween when the support arm  10  reaches the expanded position. 
     The engagement between the projections  130 ,  131  also provides a user of the collapsible circuit board mount  1  with a sense of the full expansion of the support arm  10 . 
     The base mount  11  is provided on each of the two opposite ends thereof with a stop tab  114  which is receivable in and engaged by a recess  103  defined in the support arm  10  when the support arm  10  is in the expanded position which together with the retaining means  13  retains the support arm  10  at the expanded position. 
     The collapsing mechanism  12  further comprises positioning means  123  which comprises a paw  1232  formed on at least one of the side walls  100  of the support arm  10  and a corresponding ratchet wheel  1230  having two first teeth  1231  provided thereon respectively corresponding to the stowed position and the expanded position of the support arm  10 , as shown in FIGS. 8A and 8B. FIG. 8A shows the support arm  10  at the expanded position and the paw  1232  engages one of the teeth  1231 . FIG. 8B shows the support arm  10  at the stowed position and the paw  1232  engages the other tooth  1231 . The engagement of the paw  1232  with the teeth  1231  prevents the support arm  10  from free rotation about the pivot pins  121  with respect to the base mount  11  and thus retains the support arm  10  at either the expanded position or the stowed position. 
     The teeth  1231  are shaped to allow the paw  1232  to disengage therefrom by applying a torque to the support arm  10  about the pivot pins  121 . 
     The ratchet wheel  1230  further comprises a second tooth  1234  which is positioned to prevent the support arm  10  from being further lowered, due to gravity, from the stowed position as being engaged by the paw  1232 . 
     The support arm  10  is also provided with an arced slot  1233  which is substantially concentric with the hole  122  which receives the pivot pin  121 . The slot  1233  which is formed by removing a portion of the material of the support arm  10  provides the portion of the support arm  10  around the hole  122  with deformability thereby allowing the hole  122  to be more easily rotatable about the pivot pin  121  with less physical constraint. 
     The mount base  11  has a pair of fixing devices  111  provided on the two opposite side walls  115  at each end of the elongate body thereof. Each of the fixing devices  111  comprises a sideways projection  112  fixed to the elongate body of the mount base  11  and defining a bore therein. 
     As shown in FIGS. 1,  5 A and  5 B, the sideways projection  112  forms two opposite side walls  1121  and an end wall  1122  thereby defining a channel  1123  therebetween. One of the side walls  1121  is fixed to or constitutes part of the elongate body of the mount base  11 , for example it is attached to the side wall  115  of the mount base  11  as shown in the drawings. Each of the side walls  1121  and the end wall  1122  of the fixing device  111  is provided with a pawl  113 . The pawls  113  of the side walls  1121  are opposite each other and each has a substantially triangular shape pointing toward each other thereby defining a neck  1130  therebetween. An inclined guiding edge  1131  is formed on each of the pawls  113  and converge together to define the neck  1130 . An inner-threaded cylinder  30  has an outside diameter substantially corresponding to an inscribed circle defined between the pawls  113  and is fit into the channel  1123  of the sideways projection  112  by being guided and deformed by the inclined edges  1131  of the pawls  113  and retained by the pawls  113 . The cylinder  30  has an expanded bottom end to retain the cylinder  30  in the channel  1123  of the sideways projection  112 . 
     The inner-threaded cylinder  30  substantially corresponds to the bore  1120  of the projection  112  so as to be engaged by a bolt to fix the mount base  11  to the main board. 
     Although the present invention has been described with reference to a preferred embodiment 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 ratchet wheel having teeth thereof may be alternatively positioned on the one of the base and the support arm, and the paw disposed on the other of the base and the support arm. For example, the stop tab may be alternatively positioned on one of the base and the support arm.