GB2040590A

GB2040590A - Circuit board rack

Info

Publication number: GB2040590A
Application number: GB8002311A
Authority: GB
Original assignee: CA Weidmueller GmbH and Co
Current assignee: Weidmueller Interface GmbH and Co KG
Priority date: 1979-01-24
Filing date: 1980-01-23
Publication date: 1980-08-28
Also published as: FR2447665A1; DE7901784U1; GB2040590B; FR2447665B1

Abstract

A rack for circuit boards has a pair of upright holders 1 interconnected by a plate 3. In use of the rack, the circuit board 5 is retained by a locking member 11, located on a holder 1, and which comprises a hook 15 which snaps over a fastening extension 7 on the board 5, and a groove 12 which engages an edge of plate 3. The locking lever may be accommodated in an opening 10 in the holder 1 and may be located by the sides of the opening, by lateral projections 13 on the lever engaging the face of the holder. More than one groove 12 may be provided to allow the same hook 15 to be used with plates 3 mounted at different heights. The locking lever may have an outwardly cranked extension 18 protected by the walls of the holder but accessible to enable the hook to be released from the member 7. <IMAGE>

Description

SPECIFICATION Plug-in circuit board rack This invention relates to plug-in circuit board racks of the kind that comprises a frame with two lateral holders provided with guide for edges of a circuit board, and a connecting member mounted between the holders and including a bottom plate.

It is usual to provide such racks with means to retain the inserted circuit board, for example to prevent the latter from being shaken loose by vibration.

It is possible to prevent an inserted circuit board from dropping out by securing it in the simplest possible manner namely by providing the top region of the plug-in circuit board with a security lever in a receptor of at least one of the holders, which is provided with a member adapted to grip behind the top edge of the plug-in circuit board (German Gebrauchsmuster 78 24 591).

However, such a simple security system can be used only if the top edge of the plug-in circuit board is available to this end. There are in use circuit boards on which there is not only a contact strip with contact pins or blades which are fixedly connected at one side of the board but on which the other side is already provided with a handle strip which, in terms of the spatial configuration of the plug-in circuit board assembly, covers the entire top edge of the plug-in circuit board. A security device of the kind described is not possible in such a case.In a known plug-in circuit board assembly of the kind described hereinbefore, such plug-in circuit boards can be secured in their plugged-in position by means of a locking lever, constructed as an actuating bolt which is pivotably supported between the holder and the connecting member, is pivoted into a locked position via a corresponding receptor when the plug-in circuit board is inserted, and also has an actuating portion, which slightly projects from the frame region in each position, the plug-in circuit board can be ejected by cancelling the locking action when the said actuating portion is actuated, accompanied by backward pivoting of the lever (German Patent Specification OS 20 14182).

It is a disadvantage of this construction that, especially because of the pivoted support of such a locking lever in co-operation with a plug-in circuit board or contact strip of the circuit board, differently shaped yocking levers must#be separately produced and stored for different contact strips and/or connecting members of the frame, and that furthermore unintentional operation of the actuating portion of the locking lever causes slackening of the interlocking action even if it does not in fact result in a tendency to eject the plug-in circuit board.

It is therefore the object of the present invention to provide a plug-in circuit board assembly of the kind described hereinbefore such that unintentional releasing of the interlocking action is prevented although the construction of the locking device is extremely simple.

According to one aspect of the present invention there is provided a plug-in circuit board rack comprising a pair of opposed spaced lateral holders provided with guides for respective edges of a circuit board, and a connecting member extending between the holders, which connecting member comprises a plate and electrical connecting means carried by the plate for electrical connection to the circuit board in use, at least one holder being provided with a locking member, which has an end region located by the holder and incorporating at least one recess for engaging an edge of the said plate, and which has extending from the end region in the longitudinal direction of the guide a resiliently flexible arm on which are a hook arranged to snap over an abutment on the circuit board, in use, and an operating member for operation to release the hook from the said abutment.

According to another aspect of the invention there is provided a plug-in circuit board rack comprising a frame with two lateral holders which are provided with circuit board guides and have mounted therebetween a connecting member which has a bottom plate, and a locking lever disposed in the bottom region of at least one of the holders so that on insertion of a plug-in circuit board with a contact strip thereon said lever moves into a lock position from which it can be moved away, characterised in that the bottom region of the locking lever is provided with grooves, situated at different heights, for bearing on the side edge of the bottom plate at the height appropriate to the connecting member, and the bottom region of the locking lever is positionally located on the side wall of a receptor therefor in the holder on the side wall of a receptor therefor in the holder and is provided with a resiliently pivotable upright arm which is provided with a ratchet hook adapted to grip in snap-on manner over an extension of a contact strip associated with the plug-in circuit board when this is inserted, and the arm is upwardly extended by means of a cranked operating member.

The construction of the bottom region of the locking lever with a plurality of grooves at different vertical position, the manner in which the lever bears by means of one of the grooves on the lateral edge of the bottom plate associated with the appropriate connecting member, and the location of the bottom region of the locking lever by the holder wall which adjoins the receptor of the lever in the retainer, in a simple manner ensure that one and the same kind of locking lever is sufficient for #connecting members of different heights, each calling for a different distance between the affected groove and the ratchet hook.

In terms of the locking lever this substantially simplifies the manufacture of a frame. Since the top region with the ratchet hook of the locking lever enables it to grip over a portion of the contact strip associated with the appropriate plugin circuit board by snap engagement and the arm, supporting the ratchet hook, is extended by means of a cranked operating member, it is easy to ensure that the entire locking lever will in every case remain in a security region defined by the associated holder, more particularly in terms of its operating member, so that unintentional opening of the interlock is prevented. The operating member can for example be disposed in a recess in the holder. Neverthless opening of the interlock remains very simple.It is sufficient to insert a simple tool, for example a screwdriver, into the holder to engage the operating member and to resiliently force back the arm with the ratchet hook until the snap engagement retention is released and the plug-in circuit board can be withdrawn in the upward direction.

One embodiment of the plug-in circuit board assembly will be described hereinbelow by reference to the accompanying drawings in which: Fig. 1 is a partial sectional view through a plugin circuit board assembly according to the invention, Fig. 2 is a view of the locking lever disposed in a receptor of a holder, seen in the direction of the arrow II of Fig. 1, the plug-in circuit board and its contact strips having been omitted, and Fig. 3 is a section on line Ill-Ill of Fig. 1.

The plug-in circuit board rack comprises a frame, having two spaced opposed lateral holders 1 with board guides 8, of which only the bottom region of one holder 1 is shown in Figs. 1 and 2, and a connecting member 2 with a bottom plate 3 mounted between the two lateral holders 1. An embodiment in which a spring contact strip 4 is mounted on the bottom plate 3, which is also constructed as a circuit board, and rows of screw terminals connected to the contact strip are disposed there behind on the plate 3, is particularly convenient. The strip 4 is adapted to receive the contact pins or blades of a contact strip 6 which is mounted on the circuit board 5; the contact strip 6 is provided with lateral extensions 7 which are screw-mounted to the circuit board 3.

Each holder is an upwardly tapering column, with a multiple channel cross-section as shown in Fig. 3. It has a web 9 facing the opposite holder, outer flanges 24 extending to the rear (away from the opposite holder), and parallel inner flanges 23.

In the web 9 is a longitudinal guide 8 for the circuit board, and in the lower region is a rectangular opening 10 forming a receptor for a locking lever 11. In the lower region of each holder, on the web 9, are supports 22 for the respective edges of the plate 3. In the illustrated embodiment two pairs of supports are provided so that the plate 3 can be mounted at two different levels as required. The plate is attached to the holders for example by screws. The plate and holders therefore form a rigid frame for receiving the circuit board.

A locking lever 1 1 is provided for one holder, or for each holder.

The bottom region of the locking lever 1 1 is provided with a groove 12 or with grooves 12 situated at different heights corresponding to the supports 22. Two different grooves 12 are provided in the illustrated embodiment, because two spring strips 4 of different height must be mainly considered for the conventional connecting members 2. The lateral edge of the bottom plate 3 of the connecting member 2 can be accommodated in one of the grooves 12, in the top groove of the illustrated embodiment with so-called low spring strip 4.In the procedure adopted for assembling the frame at the works, the locking lever 1 1 is or levers 11 are mounted laterally with the corresponding grooves 12 on the edge(s) of the plate 3 of the completely assembled connecting member 2, and thereafter the holders 1 are laterally plugged so that the corresponding receptors for the bottom plate 3, formed by supports 22, engage the edges of the plate 3, and are screwmounted thereto.

The middle region of the locking lever 11, above the grooves 12, has lateral projections 13 (best seen in Figure 2) which bear against the surface of the web 9 surrounding the opening 10.

In this region, the surface of the web 9 is recessed.

It will be seen that the lower region of the locking lever is thereby positively located in the frame and cannot move in any direction. Movement in the longitudinal direction of the guide 8 is prevented by engagement of the recess 12 with the edge of the plate 3, the plate being fastened to the holders 1. The plate 3 also prevents the locking lever from moving towards the opposite holder. Movement away from the opposite holder is prevented by the projections 1 3, and the sides of the locking lever are located by the corresponding sides of the opening 10.

Furthermore, above the grooves 12 and above the lateral projections 13 the locking lever 11 is provided with an upright arm 14 which is resiliently pivotable by virtue of the material (plastics) used for the locking lever, the top region of said arm supporting a ratchet hook 1 5. The ratchet hook 15 is arranged so that when the plug-in circuit board 5 is inserted the said hook can grip in snap engagement over the extension 7 of the contact strip 6, provided for screwmounting to the plug-in circuit board. To this end the ratchet hook 15 is provided with a lead-in ramp 16 on which the underside of the extension 7 can slide when the plug-in circuit board is inserted while the arm 14 of the locking lever is resiliently pivoted in the outward direction.

On the sides of the arm 14 there are provided small stop members 17 which will bear on the internal surface of the web adjoining the opening 10 when the arm 14 is further outwardly pivoted, to prevent excessive outward pivoting of the arm 14 and therefore to prevent overstretching of the material of the lever.

At the top the arm 14 is extended by means of a cranked actuating member 18 which extends on the outside of the web 9 in the recess between the flanges 23, and is provided with a terminal bead 19 fitting over an outwardly directed ramp 20 on the rear face of the web 9, above the opening 10.

To release the interlock it is sufficient to slide downwardly, on the outside of the web 9 in the bottom region thereof, a screwdriver for example, and the ramp 20 will then guide the end of the screwdriver automatically to the top, beaded termination of the actuating member 19 which in turn will be thrust outwardly, pulling back the arm 14 and therefore the ratchet hook 15, until the extension 7 is released by the ratchet hook 15 and the plug-in circuit board 5 can be withdrawn to the top of the rack.

In the interests of stability the locking lever 11 in the illustrated embodiment is made wide enough to extend to both sides of the inserted plug-in circuit board 5; the arm 14 of the said lever is provided with a slot 21 which is so arranged that the plug-in circuit board 5 can enter this region of the locking lever when the circuit board is inserted in the rack.

As can be seen from Figs. 1 and 3, the locking lever is entirely within the external profile of the holder 1 and is therefore protected against accidental operation of the member 19 to release the circuit board.

Claims

1. A plug-in circuit board rack comprising a pair of opposed spaced lateral holders provided with guides for respective edges of a circuit board, and a connecting member extending between the holders, which connecting member comprises a plate and electrical connecting means carried by the plate for electrical connection to the circuit board in use, at least one holder being provided with a locking member, which has an end region located by the holder and incorporating at least one recess for engaging an edge of the said plate, and which has extending from the end region in the longitudinal direction of the guide a resiliently flexible arm on which a hook arranged to snap over an abutment on the circuit board, in use, and an operating member for operation to release the hook from the said abutment.

2. A circuit board rack as claimed in claim 1 in which the said end region has a plurality of said recesses spaced in the longitudinal direction of the guide and the holders have correspondingly spaced supports for locating the said plate selectively at different positions.

3. A circuit board rack as claimed in claim 1 or 2 in which the locking member is disposed in an opening in the holder and has lateral projections abutting the surface of the holder adjacent to the opening, and is held in place by abutment of the said projections with the holder surface and engagement with the edge of the plate.

4. A plug-in circuit board rack comprising a frame with two lateral holders which are provided with circuit board guides and have mounted therebetween a connecting member which has a bottom plate, and a locking lever disposed in the bottom region of at least one of the holders so that on insertion of a plug-in circuit board with a contact strip thereon said lever moves into a lock position from which it can be moved away, characterised in that the bottom region of the locking lever is provided with grooves, situated at different heights, for bearing on the side edge of the bottom plate at the height appropriate to the connecting member, and the bottom region of the locking lever is positionally located on the side wall of a receptor therefor in the holder and is provided with a resiliently pivotable upright arm which is provided with a ratchet hook adapted to grip in snap-on manner over an extension of a contact strip associated with the plug-in circuit board when this is inserted, and the arm is upwardly extended by means of a cranked operating member.

5. A rack according to claim 4, characterised in that the locking lever is provided with lateral projections which are situated above the grooves and which bear on the internal side wall of the holder, which wall defines the said receptor.

6. A rack according to any of claims 1 to 5 in which the arm of the locking lever is provided approximately in its middle with a slot to accommodate the plug-in circuit board.

7. A rack according to any of claims 1 to 6 in which the top of the hook is provided with a leadin ramp.

8. A rack according to any of claims 1 to 7, characterised in that lateral stop members are provided in the top region of the arm.

9. A rack according to any of claims 1 to 8 characterised in that on the outside of the holder, the operating member extends upwardly and a tool guiding ramp, extending to the top end of the operating member, is provided on the outside of the holder.

10. A plug in circuit board rack, substantially as herein described with reference to the accompanying drawings.