Patent Application
20050124182
A backplane or midplane (hereafter called backplane) is an electronic circuit board, which may include circuits, and includes sockets into which other circuit boards or cards can be plugged. For instance, in a computer the backplane (sometimes referred to as a motherboard) is a circuit board that includes sockets for cards. The cards (also referred to as expansion cards, boards, adapters and so forth) include circuits that provide a functional capability to the computer. The card is typically made of a rigid material and is plugged into one of the computer's expansion slots e.g., connectors in the backplane. Cards have a variety of sizes designed to match corresponding socket dimensions. To provide alignment of the card to the slot, the backplane can include a guide pin and the card can include a receptacle. Inserting the guide pin into the receptacle aligns the card with the slot.
In one aspect the invention features a guidance block that includes a base and a pair of opposing card guide sides supported on a common surface of the base. The opposing card sides define a gap between the pair of opposing sides. A spring member is coupled to one of the card guide sides, partially within the gap provided between the pair of opposing sides, with the card guide sides and spring clip configured to align a circuit board disposed in the gap between with a connector.
Embodiments may include one or more of the following. The base can be connected to a backplane or a midplane. The base can include an extension region. The extension region can be configured to fit into an alignment slot in the backplane. The card guide side can include a spring region configured to attach the spring. The spring region can include an overhang member. The card guide sides can be configured such that the spring can be coupled to either of the sides. The card guide sides can include a macro alignment region. The macro alignment region can include an angled end. The guidance block can include screws that attach the base to the backplane. The spring can provide alignment of a primary side of the circuit board.
The sides can be configured to accept multiple thicknesses of circuit packs. The spring clip can include an electrically conductive material that provides an electrostatic discharge (ESD) path to ground. The base can include an angled outer region.
In another aspect, the invention features a device that includes a backplane and a guidance block. The guidance block includes a base, a pair of opposing card guide sides supported on a common surface of the base. The opposing card guide sides define a gap between the pair of opposing sides. A spring member is coupled to one of the card guide sides, partially within the gap provided between the pair of opposing sides. The card guide sides and spring clip are configured to align a circuit board disposed in the gap with a connector.
Embodiments may include one or more of the following. The base can include an extension region configured to fit into an alignment slot in the backplane. The card guide side can include a spring region configured to attach the spring. The spring region can include an overhang member. The card guide sides can be configured such that the spring can be coupled to either of the sides. The card guide sides can include a macro alignment region having an angled end. The spring can provide alignment of a primary side of the circuit board. The sides can accept multiple thicknesses of circuit boards. The spring clip can be composed of an electrically conductive material. The base can include an angled outer region
In one aspect, the guidance block includes a spring to bias a card to the primary side of the guidance block. This allows a user to insert a board into the device without regard for the thickness of the board. The spring aligns the connectors on the board with the connectors in the slot.
In another aspect, guidance blocks are provided in pairs. Providing the guidance blocks in pairs adds the advantage of both horizontal and vertical alignment of the card to the socket.
The current invention obviates the need for the traditional guide pin and receptacle to provide macro alignment of a card to a slot. The current invention does not require additional printed circuit board (PCB) real estate for a guide pin receptacle and maximizes the height of the PCB's. This allows greater I/O density per card since the space traditionally needed for a guide receptacle can be used for additional connectors.
Referring to
Referring to
While the spring clip 44 provides the advantage of ease of manufacture and assembly, other types of spring members can be used. For example, a spring member could be composed of a coil spring with a flat plate attached for the sliding surface or a wire formed leaf spring, the spring could also be made of plastic and have an optional coating of a electrically conductive material.
The spring clip 44 can be attached to either spring region 42a or 42b dependent on whether the guidance block 14 will be used as a top guidance block or bottom guidance block. In order to bias the card to the opposite side, the spring clip 44 is attached to the opposite spring region (i.e. attaching the spring to region 42a of side 50a biases the card towards side 50b). In this example (
Spring clip 44 provides horizontal alignment for the circuit pack and biases the card 12 toward side 50a (
An extension 36 from base 30 fits the shelf card guides 18. A backplane is often configured to fit a particular card thickness. Thus, shelf card guide 18 may be included on the shelf to provide alignment of the card to the slot of the shelf. Since shelf card guide 18 is the approximate thickness of the board, it may be difficult for a user to align the board to the shelf card guide 18. A user slides the extension 36 on the guidance block 14 into the shelf card guide 18, thus the user can align the board using guidance block 14 instead of the shelf card guide 18 provided on the shelf. The spring clip 44 on guidance block 14 aligns the board, allowing the user to insert the card into a wider slot (slot 52) yet still align the card to the connectors.
In one example, the base 30 and sides 50 are molded from plastic producing a unitary piece having the features discussed above. Base 30 and sides 50 could instead be composed of multiple parts bonded together to form the structure. In another example, the base 30 and sides 50 could be composed of metal (providing ESD protection) or another firm, electrically conductive material.
The exact shape and attachment of spring clip 44 can vary. In the example shown in
While in the example described above, each guidance block 14 is individually attached to backplane 10, multiple guidance blocks 14 can be grouped to form a larger unit. For example, a backplane might include eight card slots. Thus, a grouping of sixteen guidance blocks (one top and one bottom per slot) 14 provides alignment for each card slot in the backplane.
In the above example, the guidance block 14 includes a single spring to bias the card. The guidance block 14 could alternately include two springs. In this example, each side would have opposing springs. By including two springs, the card is aligned not to one side, but to the middle of the guidance block 14.
A single part could be provided out of plastic that formed the ramp block and the spring as a single unit this could then be plated to provide the ground as well.
A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
