Side-mounted lock for HBA card

Abstract

A device for locking a printed circuit board in its position, the device comprising the following: a guide rail (106, 108; 204, 206; 400; 500; 608), comprising: a slot (502, 504) extending along a first dimension and configured to accommodate an edge of a printed circuit board inserted therein; and a through hole extending along a second dimension through the guide rail and into the slot, the second dimension being perpendicular to the first dimension; a cam bolt lock (506, 508) that is attached to the guide rail and comprises the following: a cam bar (306; 402; 604); a plunger (210; 302; 404; 510, 512; 602) extending through the through-hole; and a hinge pin (308; 514, 516; 606) that couples the cam bar and the tappet; wherein the cam bar is positioned such that it rotates around the hinge pin, and wherein the rotation causes a linear movement of the plunger within the through-hole parallel to the second dimension between an extended position and a retracted position, wherein in the extended position the plunger protrudes into the slot to engage with the circuit board and lock the circuit board in its position, and wherein in the retracted position the plunger is retracted from the slot and unlocks the circuit board.

Description

BACKGROUND

[0001] This disclosure generally refers to a locking mechanism for securing circuit boards in their position. More specifically, the locking mechanism may be mounted laterally and be based on a cam latch.

[0002] JP H11 - 186 758 A describes a device for locking a printed circuit board in its position, the device comprising a guide rail comprising: a slot extending along a first dimension and configured to receive an edge of a printed circuit board inserted therein; and a cam-bolt lock attached to the guide rail comprising: a cam bolt; a plunger; and a hinge pin. SHORT DESCRIPTION

[0003] A device according to claims 1 to 8 and a printed circuit board housing according to claims 9 to 18 are disclosed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. shows a schematic representation of a partial top view of an input / output module (IOM) with a side-mounted locking mechanism according to one aspect of the application. The Fig. illustrate the operating principle of a laterally mounted locking mechanism according to one aspect of the application. Fig. shows a laterally mounted locking mechanism for locking a printed circuit board in its position according to one aspect of the present application. Fig. shows a plunger and a hinge pin of the laterally mounted lock according to one aspect of the present application. Fig. shows a top view of a cam bolt of the side-mounted lock according to one aspect of the present application. Fig. The image shows the cam bolt lock in a locked state according to one aspect of its application. Fig. shows the cam bolt lock in an unstable, unlocked state according to one aspect of the application. Fig. shows the cam bolt lock in a stable unlocked state according to one aspect of the application. Fig. shows a pair of cam bolt locks installed on a guide rail according to one aspect of the present application. Fig. shows the cross-section of the cam bolt locks and the guide rail when the locks are in the locked state, according to one aspect of the present application. Fig. shows the cross-section of the cam bolt locks and the guide rail when the locks are in the unlocked state, according to one aspect of the present application. Fig. shows a cross-sectional view of the cam bolt lock in the locked state according to one aspect of the present application. Fig. shows a cross-sectional view of the cam bolt lock in the unlocked state according to one aspect of the present application.

[0004] In the illustrations, identical numbers refer to the same elements of the illustration. DETAILED DESCRIPTION

[0005] The following description is intended to enable the person skilled in the art to manufacture and use the examples and is given in connection with a specific application and its requirements. Various modifications of the examples shown are readily apparent to the person skilled in the art, and the general principles defined herein can be applied to other examples and applications without departing from the spirit and scope of this disclosure. Therefore, the scope of this disclosure is not limited to the examples shown but is intended to be as broad as possible, consistent with the principles and features disclosed herein.

[0006] The ever-increasing demand for computing and storage capacity has led to a continuous increase in component density in computer servers, leaving less and less space for installing add-on cards and devices required for a given application. For example, an enclosure might use input / output modules (IOMs) to meet the input / output needs of the storage nodes mounted on the enclosure, and each IOM might require up to four hot-swappable host bus adapter (HBA) cards to connect host systems to the corresponding storage devices. Since the IOM is typically housed in a 1U package, the four HBA cards do not fit on the same level. One solution is to stack two HBA cards on top of each other (i.e., placing one HBA card on top of another).This HBA stacking configuration, however, presents a challenge for hot-swapping the HBA cards, as the conventional locking and unlocking mechanisms are located on the top. When multiple (e.g., two) Host Bus Adapter (HBA) cards are stacked in a 1U Input / Output Module (IOM), the conventional top-mounted locking mechanism can no longer be used.

[0007] This disclosure describes a solution for locking printed circuit boards (PCBs) in their position between a pair of guide rails. The proposed internal locking mechanism can be mounted on the side of one of the two guide rails that hold the stacked HBA cards. The internal lock can include a cam latch, a plunger, and a hinge pin connecting the cam latch and plunger. When the HBA card is inserted into a slot on the guide rail, the tip of the plunger can retract into a through-hole on the guide rail and then return to a notch on the HBA card, locking the HBA card in position. The cam latch can rotate around the hinge pin, and the rotational movement of the cam latch can be translated into a linear movement of the plunger.Therefore, the cam bar can be turned to pull the plunger out of the notch on the HBA card, allowing the HBA card to be removed.

[0008] Fig. Figure 1 shows a schematic partial top view of an input / output module (IOM) with a side-mounted locking mechanism, illustrating one aspect of the application. Fig. An IOM 100 can contain a pair of HBA subassemblies 102 and 104. Each housing can contain a pair of guide rails to accommodate one or more HBA cards. For example, HBA subassembly 102 can contain guide rails 106 and 108 that accommodate a number of HBA cards, including HBA card 110. Note that additional HBA cards can be placed below HBA card 110 and in Fig. are not shown. Fig. This also shows that each HBA card can be coupled with a handle to push or pull the HBA card along the guide rails when replacing it. For example, HBA card 110 can be connected to a handle 112, which allows the HBA card 110 to be pulled out of the HBA subassembly 102 from the front of the IOM module 100 when replacing it.

[0009] Because the HBA card can slide along the guide rails to facilitate hot-swapping or maintenance, a locking mechanism can be used to secure the HBA card in position while in operation. In conventional systems where HBA cards are on the same level and not stacked, a locking mechanism can be placed on top of the HBA card to lock it in position (e.g., via a notch on the HBA card). However, if multiple HBA cards are stacked, the top-mounted locking mechanism may no longer be applicable.Given the limited vertical clearance of the 1U IOM enclosure (which in one example may be approximately 38.7 mm, taking into account the sheet metal thickness of the top and bottom covers of the IOM enclosure) in which the stacked HBA cards are housed, a top-mounted locking mechanism may not fit in the 1U IOM enclosure.

[0010] To facilitate locking / unlocking stacked HBA cards, a side-mounted locking mechanism can be used to access and lock each stacked HBA card from the side. Each HBA subassembly can include locks mounted on the side of its guide rail. Multiple locks can be mounted on the guide rail, one lock per HBA card. Fig. Figure 1 shows, for example, a side-mounted lock 114 attached to the side of the guide rail 108 of the HBA subassembly 102. The side-mounted lock 114 can lock the HBA card 110 in position, thus preventing the HBA card 110 from sliding along the guide rails 106 and 108 when locked. According to Figure 1, to remove the HBA card 110 from the housing 102, a user can open the top cover of the IOM 100 to release the side-mounted lock 114.

[0011] Fig. Figure 116 also shows a printed circuit board (PCB) located between the HBA assemblies 102 and 104. Since PCB 116 cannot typically be replaced during operation, its position can be fixed, and an additional locking mechanism may not be necessary. Note that Fig. This only shows a portion of the components within the IOM 100. Additional components, such as the mainboard, are not shown.

[0012] The Fig. They illustrate the operating principle of the locking mechanism according to one aspect of its application. In particular, they show Fig. and Fig. Each image shows a top view of the HBA subassembly, which includes the HBA card and the guide rails. One aspect is that the HBA card can conform to the Open Compute Project (OCP) standard. For example, an OCP HBA card can have clearly defined dimensions such as 16.8 cm × 6.9 cm. Fig. Figure 2 shows an OCP-HBA card 202 positioned between guide rails 204 and 206. Each guide rail can have a slot so that a corresponding edge of the OCP-HBA card 202 can be inserted into the slot. The OCP-HBA card 202 can then slide along the guide rails, facilitating hot-swapping of the HBA card 202. Fig. This also shows that the HBA card 202 has a notch 208 on one of its longer edges. The position and size of the notch 208 can be based on the OCP standard. The tip of a plunger 210 can be inserted through a through-hole (in Fig. (not shown) in the guide rail 206 into the notch 208. Since the plunger 210 is clamped through the through hole in the guide rail 206, the HBA card 202 can be locked in its position and prevented from sliding along the guide rails when its tip is inserted into the recess 208.

[0013] Although the plunger 210 cannot move along the longitudinal direction of the guide rail 206, it can move in a vertical direction. Fig. Figure 210 shows that the plunger 210 can move to the right, as indicated by arrow 212, thereby retracting the tip of the plunger 210 from the notch 208. When the plunger 210 is retracted, the HBA card 202 can move freely along the guide rails. According to some considerations, the movement of the plunger 210 can be restricted to a plane parallel to the component mounting surface of the HBA card 210, as indicated by arrow 212.

[0014] There are various mechanisms that can push the plunger into and out of the notch on the HBA card to lock and unlock it. Some mechanisms, such as a push-pull lever, can be bulky or difficult to operate. Depending on certain aspects of the present application, a compact cam-type latch can be used to push or pull the plunger. More specifically, the plunger and cam-type latch can be coupled such that rotary movements of the cam-type latch can be converted into linear movements of the plunger, causing the plunger to move in and out of the notch on the HBA card.

[0015] Fig. Figure 1 shows a side-mounted lock for securing a printed circuit board in its position, according to one aspect of the present application. In this example, a lock 300 can comprise a plunger 302, a spring 304, a cam bolt 306, and a hinge pin 308. Fig. shows that the cam bar 306 can have a slot 320 so that the plunger 302 can be inserted into the slot 320 and connected to the cam bar 306 via the hinge pin 308. Fig. This also shows that a longitudinal axis 322 of the plunger 302, a longitudinal axis 324 of the cam bolt 306, and a longitudinal axis 326 of the hinge pin 308 intersect and are perpendicular to each other. In this way, the plunger 302 and the cam bolt 306 can each rotate about the hinge pin 308.

[0016] Fig. shows a plunger and a hinge pin of the side-mounted lock according to one aspect of the present application. In Fig. The plunger 302 can comprise a rod 310 and a locking element 312. The spring 304 surrounds the rod 310. From one perspective, the rod 310 can be cylindrical, and the locking element 312 can be in the form of a right-angled prism. The longitudinal axis 322 of the rod 310 and a longitudinal axis 328 of the locking element 312 can be perpendicular to each other. From another perspective, the right-angled prism can have rounded or chamfered edges 330 and 332, so that when an HBA card is pushed along the guide rails, the edge of the HBA card can move relatively easily along a chamfered surface 334 of the locking element 312, thereby pressing the locking element 312 toward the guide rail to allow the passage of the HBA card. For example, an average user is able to push the HBA card into the correct position by applying a force of a few Newtons (e.g.between 5 and 10 N) exerts a force on the HBA card. When the locking device 300 is installed on the guide rail, the inclined surface 334 of the locking feature 312 faces the circuit board to be installed (i.e., the front of the HBA subassembly). When the HBA card is slid into a position where the notch is aligned with the locking feature 312, the spring 304 can push the locking feature 312 into the notch and lock the HBA card in position. The dimensions of the locking element 312 can be designed to fit into the notch on the OCP HBA circuit board. From one perspective, the plunger 302 can be made of metal, e.g., die-cast aluminum, die-cast zinc, etc. Fig. Figure 308 also shows the hinge pin 308, which is inserted into a cavity on the rod 310. The cavity can be designed such that the hinge pin 308 is aligned perpendicular to the longitudinal axis 322 of the rod 310. According to one aspect, the hinge pin 308 can also be made of metal (e.g., steel, stainless steel, etc.).

[0017] Fig. Figure 1 shows a top view of a cam bolt of the side-mounted lock according to one aspect of the present application. The cam bolt 306 may comprise a handle section 314 and a cam section 316. The cam section 316 may also be referred to as the cam body. The width of the handle section 314 may be smaller than that of the cam section 316, so that when the cam bolt 306 is mounted on the side of a guide rail, the cam section 316 may be in direct contact with the outer side wall (i.e., the side wall facing away from the HBA card) of the guide rail, while the handle section 314 is not in contact with the guide rail. This arrangement may allow a user to insert a finger between the handle section 314 and the guide rail to pull the handle section 314 and thus rotate the cam bolt 306 (e.g., clockwise).For example, a user can open the top cover of the 1U-IOM enclosure and push or pull the handle part 314 to lock or unlock the cam bolt lock. The cam bolt 306 can be made of a plastic material (e.g., polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), etc.).

[0018] The cam section 316 can have a longer edge 340 and a shorter edge 342, and the pivot point 318 of the cam bolt 306 can be positioned such that the distances between the pivot point 318 and the two edges of the cam section 316 are different. For example, the longer edge 340 can be 8.5 mm long, the shorter edge 342 can be 5 mm long, and the length 344 of the handle section 314 can be 4 mm. Other dimensions are also possible. It should be noted that the pivot point 318 of the cam bolt 306 corresponds to the longitudinal axis of the hinge pin 308, since the cam bolt 306 rotates about the hinge pin 308. In the Fig. In the example shown, the distance between the pivot point 318 and the longer edge of the cam section 316 is designated D1, and the distance between the pivot point 318 and the shorter edge of the cam section 316 is designated D2. D1 can be smaller than D2. For example, D1 can be approximately 2 mm long and D2 approximately 5 mm long. This asymmetrical design of the cam section 316 facilitates the cam movement of the cam bar 306. The chamfered corner 346 of the cam section 316 allows the cam bar 306 to rotate around the hinge pin 308 without damaging the surface of the guide rail (which may be made of plastic). From one perspective, the chamfered corner 346 can be part of a circle with a radius between 1 and 2 mm. It is also possible for the chamfered corner 346 to be part of an eclipse or a circle of a different size.

[0019] In the Fig. The cam bar 306 can have through holes (e.g., shown as pivot center 318) for receiving the hinge pin 308. Alternatively, instead of through holes, the inner walls of the cam bar 306 can have recesses or indentations that receive the hinge pin 308, so that the hinge pin 308 is covered by the outer walls of the cam bar 306 and is not exposed.

[0020] Fig. Figure 1 shows the cam bolt lock in a locked state according to one aspect of its application. More precisely, in the locked state, the longer edge 412 of the cam section of the cam bolt 402 is in contact with the outer side wall (the wall facing away from the circuit board) of the guide rail 400. The plunger 404 is attached to the cam bolt 402 (e.g., via a hinge pin) and is inserted into a through-hole (in Fig. (not shown) is inserted on the guide rail 400. The through-hole is configured such that the plunger 404 can only move in one direction perpendicular to the length of the guide rail 400. The dimensions of these components, including the thickness of the guide rail 400, the length of the plunger rod 404, and the distance between the hinge pin and the edge of the cam bar 402, can be configured such that the locking element of the plunger 404 projects beyond the inner side wall (the side wall facing the circuit board) of the guide rail 400. The extended locking feature can fit into the corresponding notch on the circuit board and lock the circuit board in its position, as shown in Fig. shown. Fig. The spring 404, which surrounds the rod of the plunger 404, is also shown. The spring can be clamped between the wall of the guide rail 400 and the locking element. When the cam bolt lock is in the Fig. When the spring is in the locked position shown, it is not under tension.

[0021] Fig. The image shows the cam bolt lock in an unstable, unlocked state, according to one aspect of its application. More precisely, it shows Fig. The cam bar 402 has been moved away from the guide rail 400, so that the longer edge 412 of the cam section of the cam bar 402 is no longer in contact with the outer side wall of the guide rail 400. The rounded corner 416 can be pressed against the guide rail 400. This movement can occur when the user pulls the cam bar 402 away from the guide rail 400 or when the edge of the circuit board presses against the locking element of the plunger 404 while the circuit board is inserted into the slot of the guide rail. This movement also causes the locking element to move towards the guide rail 400 (e.g., into the through-hole of the guide rail 400) and thus retract from the notch on the circuit board. In this case, the spring 406 is compressed by the locking element and the guide rail 400.According to one aspect, the spring 406 can be compressed with a force of more than a few newtons (e.g., 5 N). The retracted latch no longer blocks the movement of the printed circuit board along the guide rails. The printed circuit board can be inserted or removed. However, this unlocked state can be unstable because when the external force ceases (e.g., when the user stops pulling on the cam latch 402, or when the edge of the printed circuit board no longer presses against the latch), the compressed spring 406 can decompress and push the latch back into the locked position, as shown in [Figure]. Fig. shown. For example, when the printed circuit board is pushed into position, the notch on the printed circuit board aligns with the plunger 404, so that the retracted locking feature can be pushed out by the spring 406 to lock the printed circuit board in position. Similarly, the user can pull out the cam 402 with one hand to retract the locking feature and, with the other hand, pull out the printed circuit board. Once the printed circuit board is pulled out, the user releases the cam 402, and the cam 402 and plunger 404 return to their original locking position. The spring constant of the spring 406 can be carefully chosen so that the user does not have to exert a large force to compress the spring 406 when pulling out the cam 402. According to one aspect, the user can exert a force of a few newtons (e.g.,Apply a force of between 1 and 10 N) to the cam bar 402 in order to pull out the cam bar 402.

[0022] Fig. The image shows the cam bolt lock in a stable, unlocked state, according to one aspect of its application. More precisely, it shows Fig. that the cam bolt 402 has rotated clockwise (e.g., by being pulled by a user), so that the shorter edge 414 of the cam section of the cam bolt 402 is now in contact with the outer side wall of the guide rail 400. As mentioned earlier, the distance between the hinge pin and the shorter edge 414 of the cam section can be greater than that of the longer edge 412. Therefore, a cam effect can be generated in which the rotational movement of the cam bolt 402 is converted into a linear movement of the plunger 404 attached to the cam bolt 402. In this example, a sideways or clockwise rotation of the cam bolt 402 can cause the plunger 404 to move to the right, away from the guide rail 400. This movement effectively pulls the locking feature toward the guide rail 400 (e.g.,into the through-hole on the guide rail 400), thereby retracting the locking feature from the notch on the circuit board. The retracted locking feature no longer blocks the movement of the circuit board along the guide rails. As shown in . Fig. As shown, the spring 406 is compressed between the locking element and the wall of the guide rail 400 when the lock is in the stable unlocked position. When the lock is in the stable unlocked state, the shorter edge 414 of the cam bolt 402 is in contact with the guide rail 400, thus preventing decompression of the compressed spring 406. In other words, when the cam bolt 402 is in the Fig. If the cam lock is rotated or pulled in the indicated position, the locking feature can remain retracted, and the unlocked state can remain stable. When the cam lock is in this stable unlocked state, a printed circuit board (PCB) can move freely along the guide rails, and the user can install or uninstall the PCB. After inserting the PCB into the guide rails, the user can return the cam lock 402 to its original position by turning it counterclockwise. Fig. Turn or push into the locked position shown.

[0023] Fig. shows a pair of cam bolt locks installed on a guide rail, according to one aspect of the present application. Fig. A guide rail 500 can contain a pair of slots (e.g., slots 502 and 504) for receiving printed circuit boards, one slot per board. In this example, the HBA subassembly can accommodate two HBA cards. Fig. Figure 500 also shows a pair of cam bolt locks (e.g., locks 506 and 508) mounted on the outer side wall of the guide rail 500. Each lock can be mounted on the side of a corresponding slot. The wall of the guide rail 500 may also include thickened segments to which the locks 506 and 508 are attached, as indicated by a dashed circle 520. The guide rail 500, which may be made of plastic or another material, may include additional material at location 520 to provide space for the cavity that accommodates the plunger of the cam bolt lock 506 (the cavity and plunger are shown in Figure 500). Fig. (not shown). In the Fig. In the example shown, the cam bolt locks 506 and 508 are in the locked state, i.e., their locking features extend beyond the inner wall of the guide rail 500 to lock the circuit boards inserted into the slots 502 and 504 in their position.

[0024] Fig. shows the cross-section of the cam bolt locks and the guide rail when the locks are in the locked position, according to one aspect of the present application. As in Fig. As shown, the cam bolt locks 506 and 508 are in the locked position. More precisely, the plungers 510 and 512 of the cam bolt locks 506 and 508 are extended into the slots 502 and 504, respectively. Each plunger can be enclosed by a cavity 522 on the guide rail 500. The cavity 522 can have a wider section to accommodate the spring and locking element and a narrower section to confine the plunger rod. The narrower section prevents the plunger and spring from protruding from the cavity through the outer wall of the guide rail 500. The width of the narrower section can be between 1 / 2 and 3 / 4 of the width of the wider section. Fig. Figure 506 also shows that each cam bolt lock has a hinge pin connecting the plunger and the cam bolt. For example, cam bolt lock 506 includes hinge pin 514, and cam bolt lock 508 includes hinge pin 516. Note that the plunger and hinge pin, which are perpendicular to each other, effectively secure the cam bolt lock to the guide rail 500, and no additional fastening mechanism (e.g., screws) is required.

[0025] Fig. This shows the cross-section of the cam bolt locks and the guide rail when the locks are in the unlocked state, according to one aspect of the present application. In this example, cam bolt locks 506 and 508 are in a stable, unlocked state in which their cam bolts have been pulled (or rotated) to the side. Consequently, the plungers are pulled out of the slots in the guide rail 500. For example, plunger 510 is pulled out of slot 502 and plunger 512 is pulled out of slot 504. Fig. This also shows that any spring between the locking element (which is wider than the plunger rod) and the narrower section of the cavity can be compressed. However, since the shorter edge of the cam bar is in contact with the outer side wall of the guide rail 500, the plunger is prevented from being pushed towards the circuit board by the compressed spring.

[0026] Fig. Figure 1 shows a cross-sectional view of the cam bolt lock in the locked state, according to one aspect of the present application. More precisely, it shows Fig. a plunger 602 and a cam bar 604, which are connected to each other by a hinge pin 606. The cam bar 604 can be positioned next to a guide rail 608, facing away from the side of the guide rail 608 that accommodates printed circuit boards. The plunger 602 can be inserted into a cavity 610 formed in the guide rail 608. The cavity 610 can have a wider section 614 to accommodate a widened segment (i.e., the locking function) of the plunger 602 and a spring 612, as well as a narrower section 616. In the Fig. In the example shown, the cam bolt lock is in the locked state, with the plunger 602 fully extended to the left or to the inner edge of the guide rail 608. As mentioned earlier, the fully extended plunger can engage in a notch on a circuit board that is inserted into a slot on the guide rail 608, thus locking the circuit board in its position. In this case, the spring 612 is not tensioned.

[0027] Fig. shows a cross-sectional view of the cam bolt lock in the unlocked state according to one aspect of the present application. In the Fig. In the example shown, the cam bolt 604 (towards the viewer) is rotated such that its shorter edge is in contact with the guide rail 608. When the cam bolt 604 is in this position, the hinge pin 606 can move further away from the guide rail 608, thereby pulling the plunger 602 to the right and unlocking the circuit board. In this case, the spring 612 can remain compressed until the cam bolt 604 rotates back into the unlocked position.

[0028] As from the Fig. The installation of a cam bolt lock may involve the following: placing the spring 612 around the plunger rod 602; inserting the plunger rod 602 from the side of the guide rail 608 facing the circuit board into the cavity 610 (note that you may need to compress the spring 612 to ensure that a substantial portion of the rod emerges from the cavity 610); attaching the hinge pin 606 to the plunger 602; and then attaching the cam bolt 604 to the hinge pin 606.

[0029] In general, this disclosure describes a solution to the problem of locking hot-swappable printed circuit boards (PCBs) stacked on top of each other. More specifically, a cam-latch-based locking mechanism can be used, where a rotary motion of the cam latch is converted into a linear motion of a plunger connected to the cam latch. The linear motion of the plunger locks and unlocks a PCB held between a pair of guide rails. Due to limited vertical clearance, the cam latch lock is mounted laterally to the guide rail, and the locking plunger engages the PCB from the side (e.g., the plunger moves in a plane parallel to the component mounting surface of the PCB). One cam-latch lock can be used for each PCB.OCP-HBA cards were consistently used as examples in the description of the cam-bolt lock's operating principle. In practice, such side-mounted cam-bolt locks can be used to lock any type of printed circuit board (PCB), as long as the PCB has a predefined notch to allow the locking mechanism of the cam-bolt lock to engage. For example, the OCP-HBA card has two symmetrical notches on opposite edges, while another type of PCB may have an asymmetrical arrangement of notches (e.g., only one notch in total or more than one notch on one edge). It is also possible to use more than one (e.g., two) cam-bolt locks mounted on the side of the guide rails to lock the PCB. Furthermore, the... Fig.The guide rails, which hold two stacked printed circuit boards, are shown. In practice, fewer (e.g., one) or more (e.g., four) printed circuit boards can be held between the pair of guide rails, and a corresponding number of cam-type locking mechanisms can then be used to lock these printed circuit boards in their position.

[0030] One aspect of the present application provides a device for locking a printed circuit board (PCB) in its position. The device may include a cam lock, a plunger, and a hinge pin connecting the cam lock and the plunger. The cam lock is positioned to rotate about the hinge pin, and the rotation of the cam lock causes a linear movement of the plunger in a plane parallel to a component mounting surface of the PCB, thereby facilitating the locking and unlocking of the PCB.

[0031] In one variation of this aspect, the plunger is intended to engage in a notch on the circuit board in order to lock the circuit board in its position.

[0032] In another variant, the plunger is to engage in the notch via a through-hole located on a guide rail for holding the circuit board.

[0033] In another variant, the rotation of the cam bar causes the plunger to move into the notch to lock the circuit board in its position, or to retract from the notch to unlock the circuit board.

[0034] In one variation of this aspect, the cam bar comprises a handle and a body, with the body having a shorter edge and a longer edge.

[0035] In another variant, the circuit board is locked between a pair of guide rails when the cam lock rotates into a position where the longer edge of the body rests against a first guide rail, and the circuit board is unlocked between the pair of guide rails when the cam lock rotates into a position where the shorter edge of the body rests against the first guide rail.

[0036] In one variation of this aspect, one end of the plunger may have a chamfered surface so that, when the circuit board is pushed along a pair of guide rails, an edge of the circuit board pushes the plunger from a locked position to an unlocked position.

[0037] In another variation, the device can also include a spring surrounding the plunger. The spring is not compressed when the plunger is in the locked position and is compressed when the plunger is in the unlocked position.

[0038] In one variation of this aspect, the plunger can be made of metal (e.g., aluminum die-casting, zinc die-casting, etc.) and the cam bar can be made of plastic (e.g., polytetrafluoroethylene (PTFE) and polyvinyl chloride (PVC)).

[0039] One aspect of the present application provides an enclosure for printed circuit boards (PCBs). The PCB enclosure may include a pair of guide rails configured to hold one or more PCBs, each PCB comprising a notch on an edge adjacent to a first guide rail and at least one cam-locking mechanism attached to the first guide rail. The cam-locking mechanism is configured to lock the PCB in position. The cam-locking mechanism may include a cam bolt, a plunger, and a hinge pin connecting the cam bolt and plunger. The cam bolt is positioned to rotate about the hinge pin, and the rotation causes a linear movement of the plunger in a plane parallel to a component mounting surface of the PCB, thereby facilitating the locking and unlocking of the PCB.

[0040] The foregoing descriptions serve only for illustration and description. They are not exhaustive and do not limit the scope of this disclosure to the forms disclosed. Accordingly, many modifications and variations will be obvious to those skilled in the art.

Claims

[1] A device for locking a printed circuit board in its position, the device comprising: a guide rail (106, 108; 204, 206; 400; 500; 608), comprising: a slot (502, 504) extending along a first dimension and configured to accommodate an edge of a printed circuit board inserted therein; and a through hole extending along a second dimension through the guide rail and into the slot, the second dimension being perpendicular to the first dimension; a cam bolt lock (506, 508) that is attached to the guide rail and comprises the following: a cam bar (306; 402; 604); a plunger (210; 302; 404; 510, 512; 602) extending through the through-hole; and a hinge pin (308; 514, 516; 606) that couples the cam bar and the tappet; wherein the cam bar is positioned such that it rotates around the hinge pin, and wherein the rotation causes a linear movement of the plunger within the through-hole parallel to the second dimension between an extended position and a retracted position, wherein in the extended position the plunger protrudes into the slot to engage with the circuit board and lock the circuit board in its position, and wherein in the retracted position the plunger is retracted from the slot and unlocks the circuit board. [2] The device according to claim 1, wherein the plunger is to engage with a notch (208) in the edge of the printed circuit board in order to lock the printed circuit board in its position. [3] The device according to claim 2, wherein the rotation of the cam latch causes the plunger to protrude into the notch to lock the circuit board in its position, or to retract from the notch to unlock the circuit board. [4] The device according to claim 1, wherein the cam bar comprises a handle and a body, and wherein the body comprises a shorter edge (342; 414) and a longer edge (340; 412). [5] The device according to claim 4, wherein the circuit board is locked between a pair of guide rails (106, 108; 204, 206) when the cam bar rotates into a position in which the longer edge of the body rests against a first guide rail, and wherein the circuit board is unlocked between the pair of guide rails when the cam bar rotates into a position in which the shorter edge of the body rests against the first guide rail. [6] The device according to claim 1, wherein an end of the plunger comprises a head with a chamfered surface (334) configured such that when the plunger is in the extended position while the circuit board is inserted into the slot, an edge of the circuit board contacts the chamfered surface and pushes the plunger from the extended position to the retracted position, wherein the chamfered surface converts a translation of the circuit board parallel to the first dimension into a translation of the plunger parallel to the second dimension. [7] The device according to claim 6, further comprising a spring (304; 406; 612) surrounding the plunger and held between the guide rail and the head of the plunger, wherein the spring is configured to push the plunger in the direction of the extended position. [8] The device according to claim 1, wherein the plunger comprises metal and wherein the cam bar comprises plastic. [9] A printed circuit board enclosure comprising the following: a pair of guide rails (106, 108; 204, 206) configured to hold a printed circuit board, each of the guide rails comprising a slot (502, 504) extending along a first dimension and configured to receive an edge of the printed circuit board, a first guide rail of the pair of guide rails comprising a through-hole extending along a second dimension through the first guide rail and into the slot of the first guide rail, the second dimension being perpendicular to the first dimension; and a cam bolt lock (506, 508) attached to the first guide rail, wherein the cam bolt lock serves to lock the circuit board in its position, and wherein the cam bolt lock comprises the following: a cam bar (306; 402; 604); a plunger (210; 302; 404; 510, 512; 602) extending through the through-hole; and a hinge pin (308; 514, 516; 606) that couples the cam bar and the tappet; wherein the cam bar is positioned so that it rotates around the hinge pin, and wherein the rotation causes a linear movement of the plunger within the through-hole parallel to the second dimension between an extended position and a retracted position, wherein in the extended position the plunger protrudes into the slot to engage with the circuit board and lock the circuit board in its position, and wherein in the retracted position the plunger is retracted from the slot and unlocks the circuit board. [10] The printed circuit board housing according to claim 9, wherein the plunger is configured to engage in a notch (208) in one of the edges of the printed circuit board to lock the printed circuit board in its position. [11] The printed circuit board housing according to claim 9, wherein the rotation of the cam latch causes the plunger to protrude into the notch to lock the printed circuit board in its position, or to retract from the notch to unlock the printed circuit board. [12] The printed circuit board housing according to claim 9, wherein the cam latch comprises a handle and a body, and wherein the body comprises a shorter edge (342; 414) and a longer edge (340; 412). [13] The printed circuit board housing according to claim 12, wherein the printed circuit board is locked between the pair of guide rails when the cam bar rotates into a position in which the longer edge of the body rests against the first guide rail, and wherein the printed circuit board is unlocked between the pair of guide rails when the cam bar rotates into a position in which the shorter edge of the body rests against the first guide rail. [14] The printed circuit board housing according to claim 9, wherein an end of the plunger comprises a head with a chamfered surface (334) configured such that when the plunger is in the extended position while the printed circuit board is inserted into the slot, the edge of the printed circuit board contacts the chamfered surface and pushes the plunger from the extended position to the retracted position, wherein the chamfered surface converts a translation of the printed circuit board parallel to the first dimension into a translation of the plunger parallel to the second dimension. [15] The printed circuit board housing according to claim 14, wherein the cam bolt lock further comprises a spring (304; 406; 612) surrounding the plunger and held between the guide rail and the head of the plunger, the spring being configured to push the plunger in the direction of the extended position. [16] The printed circuit board housing according to claim 9, wherein the plunger comprises metal and the cam bar comprises plastic. [17] The printed circuit board enclosure according to claim 9, wherein the pair of guide rails is configured to accommodate multiple stacked Open Compute Project (OCP) Host Bus Adapter (HBA) cards (202). [18] The printed circuit board housing according to claim 9, wherein the pair of guide rails comprises multiple slots to accommodate multiple vertically stacked printed circuit boards, wherein the housing comprises multiple cam locks, and wherein each cam lock serves to lock / unlock a corresponding printed circuit board.

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