Apparatus And Method For Retaining Circuit Boards
Apparatus for retaining a plurality of circuit boards includes a chassis that defines an array of mounting surfaces. Each mounting surface is configured to receive a bracket attached to one of the plural circuit boards. A retention bar is hingingly attached to the chassis at a first axis oriented transversely to the array. A lever is configured to rotate the bar about the first axis from an open position in which the brackets may be engaged with the mounting surfaces, to a closed position in which the bar retains the brackets against the mounting surfaces. An arm is configured to hinge at a second axis and to actuate the lever as the arm is rotated about the second axis.
This invention relates generally to techniques for retaining circuit boards in electronic systems.
BACKGROUNDMany electronic systems such as computing devices include several printed circuit boards that must be interconnected. For example, in a desktop computer, expansion cards are typically inserted into connectors that are mounted on and connected to a motherboard or system board. Once interconnected, the circuit boards must be kept in place physically so that their interconnections remain intact. The term “circuit board” as used herein is intended to include all types of circuit boards including, without limitation, printed circuit boards, expansion cards, motherboards, system boards and the like.
An arm 114 is also included in apparatus 100. Arm 114 may be detachable from chassis 104 in some embodiments or permanently attached to chassis 104 in other embodiments. When arm 114 is attached to chassis 104, it is configured to hinge at an axis 116 between up and down positions relative to chassis 104.
The actuation of lever 118 by arm 114 may be accomplished in a variety of ways. In the illustrated embodiment, arm 114 includes an arcuate surface 120 for engaging lever 118. As illustrated in closeup at
In some embodiments, retention bar 110 may be biased toward the open position. This bias may be accomplished in a variety of ways. In one class of embodiments, a torsion spring may be placed along retention bar 110 to provide the bias. For example, the torsion spring may be placed at the end of retention bar 110 opposite lever 118, providing a torque on retention bar 110 relative to chassis 104. In other embodiments, other bias means may be employed. For embodiments that do not include a bias, retention bar 110 may be designed to rest against the wall of chassis 104 when in the open position, or may be designed such that friction at axis 112 is sufficient to keep retention bar 110 in the open position once it has been raised manually.
In embodiments where arm 114 is detachable from chassis 104, a variety of techniques can be employed to attach the arm to the chassis. In the illustrated embodiment, hooks 128 engage removably with corresponding shafts 130 to create the hinge at axis 116. Although hooks 128 are shown on arm 114 and shafts 130 are shown on chassis 104, in alternative embodiments hooks 128 may be provided on chassis 104 instead, and shafts 130 may be provided on arm 114 instead, or some combination thereof.
To further help in keeping retention bar 110 in the closed position when arm 114 is down, at least one rib 132 may be provided on arm 114 (see
In some embodiments, one or more flexible ribs 134 may be provided on the under side of arm 114 as shown in
It may also be beneficial in some embodiments to include one or more rigid ribs 142 on arm 114. Rigid rib 142 may be configured to contact edge 136 of circuit board 102. Alternatively, rigid rib 142 may be configured to contact alignment structures 144 that are attached to circuit boards 102 (see
In the embodiment shown, arm 114 includes both flexible ribs 134 and rigid rib 142. With this configuration, each of circuit boards 102 is retained at three points when arm 114 is down: at bracket 108, at edge 136 near the center of the circuit board, and at the end 146 of the circuit board 102 opposite bracket 108.
In the embodiment shown, hinge axis 116 is parallel with retention bar axis 112 such that arm 114 is aligned with circuit boards 102. In alternative embodiments, arm 114 may hinge at right angles to circuit boards 102 and axis 112, or may hinge otherwise. Also in the embodiment shown, when plural circuit boards 102 are installed, the cards are oriented parallel to each other (as are slots 156) and perpendicular to hinge axis 116. Other orientations may be used.
It is useful to be able to latch arm 114 once it reaches the down position so that circuit boards 102 are better retained underneath arm 114. This may be accomplished in a variety of ways. For example, referring now to
Although a variety of shapes, arrangements and techniques may be used to implement retention bar 110 and lever 118, the exemplary embodiment discussed above is shown in more detail in
A preferred method for using apparatus 100 to retain plural circuit boards 102 will now be described with reference to
While the invention has been described in detail with reference to preferred embodiments thereof, the described embodiments have been presented by way of example and not by way of limitation. It will be understood by those skilled in the art and having reference to this specification that various changes may be made in the form and details of the described embodiments without deviating from the spirit and scope of the invention as defined by the appended claims.
Claims
1. Apparatus for retaining a plurality of circuit boards, comprising:
- a chassis defining an array of mounting surfaces, each configured to receive a bracket attached to one of the plural circuit boards;
- a retention bar hingingly attached to the chassis at a first axis oriented transversely to the array and having a lever configured to rotate the bar about the first axis from an open position in which the brackets may be engaged with the mounting surfaces to a closed position in which the bar retains the brackets against the mounting surfaces; and
- an arm configured to attach to the chassis, hinged at a second axis when so attached, and configured to actuate the lever as the arm is rotated about the second axis.
2. The apparatus of claim 1, wherein:
- the arm comprises an arcuate surface for engaging the lever such that a point of contact between the arm and the lever slides along the arcuate surface as the lever is actuated.
3. The apparatus of claim 2, wherein:
- the lever is configured to slip over one end of the arcuate surface when the bar has reached the closed position.
4. The apparatus of claim 1, wherein:
- the retention bar is biased toward the open position.
5. The apparatus of claim 1, further comprising:
- at least one hook disposed on either the arm or the chassis and configured to engage removably with a corresponding shaft on the chassis or the arm to create the hinge at the second axis.
6. The apparatus of claim 1, further comprising:
- at least one rib on the arm configured to contact a side of the retention bar opposite the array of mounting surfaces when the bar has reached the closed position.
7. The apparatus of claim 1, wherein the arm is configured to hinge at the second axis between up and down positions, and further comprising:
- at least one flexible rib on the arm configured to contact an edge of at least a first circuit board when the arm is in the down position; and
- at least one rigid rib on the arm configured to contact either the edge of the first circuit board or an alignment structure attached to the first circuit board when the arm is in the down position.
8. The apparatus of claim 1, wherein:
- the second axis is parallel to the first axis.
9. The apparatus of claim 1, further comprising:
- a latch formed between the chassis and an end of the arm radially opposite the second axis, configured to releasably hold the arm in the down position.
10. Apparatus for retaining a plurality of circuit boards, comprising:
- a chassis defining an array of slots for receiving the plural circuit boards such that the circuit boards when installed in the slots are oriented parallel to each other and perpendicular to a hinge axis;
- an arm configured to hinge at the hinge axis between up and down positions and to be latched when in the down position;
- at least one alignment structure configured to be fixedly attached to at least a first one of the plural circuit boards; and
- at least a first rib on the arm configured to contact the at least one alignment structure when the arm is in the down position.
11. The apparatus of claim 10, wherein:
- the first rib is sufficiently long to extend across the entire width of the array measured parallel to the hinge axis.
12. The apparatus of claim 10, wherein:
- the first rib is rigid.
13. The apparatus of claim 10, wherein:
- the first one of the plural circuit boards comprises a bracket at a first end for engaging the chassis; and
- the at least one alignment structure is disposed at a second end of the circuit board opposite the first end.
14. The apparatus of claim 13, further comprising:
- at least a second rib on the arm configured to contact, when the arm is in the down position, a retention bar disposed above the bracket.
15. The apparatus of claim 10, further comprising:
- a plurality of flexible ribs, each configured to contact an edge of one of the plural cards when the arm is in the down position.
16. The apparatus of claim 10, wherein:
- the arm is configured to removably attach to the chassis at the hinge axis.
17. The apparatus of claim 16, wherein:
- the removable attachment of the arm to the chassis is accomplished with either a hook or a shaft on the arm that is configured to engage with a corresponding shaft or hook on the chassis at the hinge axis.
18. A method for retaining a plurality of circuit boards, comprising:
- orienting the plural circuit boards in a chassis such that they are parallel to each other and perpendicular to a hinge axis;
- placing brackets attached to the plural circuit boards over mounting surfaces of the chassis;
- pivoting an arm around the hinge axis to cause an arcuate surface of the arm to move a retention bar into a closed position over the brackets such that the retention bar urges the brackets against the mounting surfaces; and
- latching the arm in place.
19. The method of claim 18, further comprising:
- contacting a rib of the arm to an edge of at least one of the plural cards.
20. The method of claim 18, wherein the arm is removable from the chassis and wherein the method further comprises:
- attaching either a hook or a shaft of the arm to a corresponding shaft or hook on the chassis at the hinge axis.
Type: Application
Filed: Jul 31, 2009
Publication Date: Feb 3, 2011
Inventor: Tom J. Searby (Eaton, CO)
Application Number: 12/533,111
International Classification: H05K 7/04 (20060101);