GB2201453A

GB2201453A - A module retaining clip; tool

Info

Publication number: GB2201453A
Application number: GB08804181A
Authority: GB
Inventors: Jeffrey Alan Goldsmith
Original assignee: MILLBANK ELECTRONICS GROUP LIM
Current assignee: MILLBANK ELECTRONICS GROUP LIM
Priority date: 1987-02-25
Filing date: 1988-02-23
Publication date: 1988-09-01
Also published as: GB8804181D0; GB8704386D0

Abstract

The clip 26 for retaining a module in the form of a printed circuit board (20, Figure 9) and a panel 22 within a main frame 28 of electronic equipment comprises a central curved leaf member (30) bounded by support members 32, 34. Each support member has an upright flange 36 provided with an aperture 40 by which clip 26 can be secured to panel 22, and a backwardly extending flange 38 provided with an aperture 42 which enables frame of board to be secured to panel 22. The leaf member has a latching member 44 and a member 46 engageable by a special tool (50, Figures 4-7) to enable extraction of the module from the main frame. The latching member is provided with a pair of engaging faces (45). The member (46) has a projecting part (48) with a backwardly facing face (47) for engagement with the tool. It is envisaged that panel 22 has slots to enable hooks (56, 58 Figure 4) to pass through to release respective clips 26 so that module can be removed from main frame using tool as a handle. <IMAGE>

Description

A MODULE RETAINING CLIP.

The present invention relates to a module retaining clip.

In electronic equipment a plurality of modules each containing a printed circuit together with discrete components, e.g. transistors either incorporated within the printed circuit or soldered thereto are slidable on rails mounted on a main frame and are plugged into sockets located at the back thereof and held in position by screws provided at the front of the main frame.

However, the provision of screws to enable the individual modules to be removed either for repair or replacement has the disadvantage that modules can easily be removed by unauthorized persons.

It is therefore an object of the present invention to overcome this disadvantage by making the modules secure in the main frame against theft or unauthorized removal, whilst at the same time enabling them to be easily and quickly released by an authorized person.

According to the present invention there is provided a clip for retaining a module in the form of a printed circuit board and a panel within a main frame of electronic equipment; said clip including: means for securing it to the back face of the panel; means for engaging the main frame in order to prevent said module being removed once it is in position; and means enabling withdrawal of the module from the main frame when said engaging means has been released with the aid of a special tool.

The engaging means is preferably in the form of a resilient curved leaf member having a latching member at the end thereof to engage a part of the main frame, said leaf member being naturally biased into the engaging position.

The means enabling withdrawal of the module may comprise a projection provided on the free end of the leaf member having a surface engageable with a surface at the end of said tool, the tool in the same operation releasing the latching member from its engagement with the main frame.

Preferably the latching means comprises two projections between which the projection engageable with the tool is positioned.

The leaf member of the clip is preferably integrally formed and centrally located between the means for securing the clip to the back face of the panel.

A pair of clips may be provided at the top and bottom of the module. In this case the tool is substantially 'U"-shaped, the base of the "U" forming a handle to enable extraction of the module from the main frame once the latching means has been released.

The clips ae preferably made of Nylon (Registered Trade Mark).

The means for securing the clip to the back face of the panel may comprise a pair of flanges integrally formed on either side of the leaf member, each flange having an aperture to enable the clip to be secured to the back face of the panel by appropriate means.

The present invention will now be described in greater detail by way of example with reference to the accompanying drawings, wherein: Figure 1 is a front elevation view of one preferred form of module retaining clip; Figure 2 is a plan view of the clip shown in Figure 1; Figure 3 is a side sectional view of the clip shown in Figure 1 taken along the line X-X; Figure 4 is.a side elevation view of a preferred form of module removal tool which enables the clip to be released from holding the module tightly in position; Figure 5 is a rear view of the tool shown in Figure 4; Figure 6 is a plan view of the tool shown in Figure cr; Figure 7 is an enlarged view of the upper arm of the tool which enables the release of the clip and then enables the tool to become a handle for removal of the module from the main frame;; Figure 8 is a- front view of the panel to which the printed circuit board forming the module is attached; Figure 9 is a plan view of the clip and printed circuit board attached to the panel; and Figure 10 is a side sectional elevation view illustrating firstly how the clip enables the module to be tightly held in the main frame, and secondly how the tool is used to release the clip and enable the module to be removed from the main frame.

Referring first to Figures 9 and 10 in order to obtain a general idea of the parts involved a frame 21 for holding a printed circuit board 20 is secured to a front panel 22 of a module via a module retaining clip 26 by means of a bolt 24. The purpose of the clip 26 is to retain the module within the main frame 28 in which all the modules which make up the electronic equipment are contained.

Referring now to Figures 1 to 3, the clip 26 is shown in greater detail. It comprises a central curved leaf member 30 which is bounded on either side by integrally formed support members 32 and 34. Each support member has an upright flange 36 and a backwardly extending flange 38. Each upright flange 36 is provided with an aperture 40 by which the clip 26 can be secured to the back face of the panel 22 by any suitable means.

Each backwardly extending flange 38 is provided with an aperture 42 which enables the frame 21 of the printed circuit board 20 to be secured to the front panel 22 via the clip 26.

The central curved leaf member 30 of the clip has a latching member 44 and a member 46 which is engageable by the tool to enable extraction of the module from the main frame. As shown in Figure 2, the latching member 44 is square "C" shaped and has a pair of nearly vertical engaging faces 45. The member 46 is formed within the latching member 44 and has a projecting part 48 with a backwardly facing nearly vertical face 47 for engagement with the tool. The natural unbiased position of the central leaf member 30 is as shown in Figure 3. As shown in Figure 10 when in position to retain a module within the main frame 28 it is sprung downwards, the engaging faces 45 being vertical and making contact with a corresponding vertical face 27 on the main frame 28 within a space 29.In order to release the module from the main frame, the central leaf member 30 of the clip has to be depressed even further against a natural bias which wants to return it to the position shown in Figure 3.

The special tool designed to release the module from the main frame is shown in Figures 4 to 7. The tool 50 is generally "U1, shaped being substantially square in cross section and has an upper arm 52 and a lower arm 54.

At the end of each arm projects respective hook members 56 and 58, the hook members also being substantially square in cross section. The end of the upper hook 56 is shown in greater detail in Figure 7. It is provided with a downwardly facing notch. 60 having a vertical face 61 and an inclined face 62. The notch 60 on the lower hook 58 is identical except that it is upward facing. The free end of each hook is provided with a part rolmded nose 64 Referring to Figure 8, the front panel 22 is provided with rectangular slots 66 near the top and bottom thereof to enable the respective upper and lower hooks 56 and 58 of the tool 50 to pass therethrough in order to enable the noses 64 to depress the leaf member 30 and thus release the clips so that the module can be removed from the main frame using the tool 50 as a handle.It will be appreciated that each module has a first clip associated with the upper part of the front panel as shown in Figure 10 and a second clip of identical construction which is associated with the lower part of the front panel, except that the second clip is positioned the other way up, so that the latching member at the end of the central leaf member is poining downwards.

Initially, to insert the module into the main frame, the upper and lower clips have their central leaf members 30 manually depressed, the tip of the latching member sliding along the underneath part 70 of the main frame 28 (as seen in Figure 10). When the module is home so that the plugs at its rear end connect into the appropriate sockets at the back of the main frame, the engaging faces 45 of the upper and lower clips engage behind the vertical faces 27 of the main frame, the central leaf member being urged into the space 29 in the main frame due to its natural tendency to revert to the unbiased position shown in Figure 3. Thus once the latching members 44 of the upper and lower clips have latched in the spaces 29, the module cannot be removed from the main frame.

In order to make an authorized release of the module from the main frame, the removal tool is used.

Such tool is normally either kept safely locked away or is in the possession of only authorized persons. The upper and lower hooks 56 and 58 of the tool 50 are inserted in the two rectangular slots 66 of the front panel 22. On being pushed home, the rounded face 64 first of all depress the central leaf member 30 of the respective clips further, so as to release them from engagement with the main frame and then the projecting part 48 of the members 46 of the upper and lower clips engages in the respective notches 60 of the upper and lower hooks 56 and 58. In each case the face 47 of the member -46 engaging against the vertical face 61 of the notch 60.Having released the clips from the main frame, the whole module can be withdrawn from the main frame by using the tool 50 as a handle.

Due to the shape of the part rounded nose 64, the leading edge of the tool allows it to be used for module insertion. Insertion of the module into the main frame can thus be simplified by the introduction of the withdrawal tool such that it rests on the engaging face 45 this means that the leaf member 30 can be depressed without the withdrawal tool locking into place.

Both the clip-26 and the removal tool 50 are made of Nylon (Registered Trade Mark) which has all the necessary properties of natural resilience for the central leaf member 30 and rigidity and strength for other parts.

Since the clips are normally hidden when in position, it is impossible for them to be damaged or broken by some unauthorized person wishing to remove one or more modules from the main frame.

Furthermore due to the fact that the hole 66 in the front panel 22 are rectangular it makes it very difficult- for an unauthorized person to attempt removal by use of a knitting needle or screw driver.

Claims

CLAIMS : -

1. A clip for retaining a module in the form of a printed circuit board and a panel within a main frame of electronic equipment; said clip including (a) means for securing it to the back face of the panel; (b) means for engaging the main frame in order to prevent said module being removed once it is in position; and (c) means enabling withdrawal of the module from the main frame when said engaging means has been released with the aid of a special tool.

2. A clip according to claim 1, wherein the engaging means is in the form of a resilient curved leaf member having latching means at the end thereof to engage a part of the main frame, said leaf member being naturally biased into the engaging position.

3. A clip according to claim 2, wherein the means enabling withdrawal of the module comprises a projection provided on the free end of the leaf member having a surface engageable with a surface at the end of said tool, the tool in the same operation releasing the latching member from its engagement with the main frame.

4. A clip according to claim 2 or 3, wherein said latching means comprises two projections between which the projection engageable with the tool is positioned.

5. A clip according to any one of the preceding claims 2 to 4, wherein the leaf member of the clip is integrally formed and centrally located between the means for securing the clip to the back face of the panel.

6. A clip according to any one of the preceding claims, wherein the means for securing the clip to the back face of the panel comprises a pair of flanges integrally formed on either side of the leaf member, each flange having an aperture to enable the clip to be secured to the back face of the panel.

7. A module in the form of the printed circuit board which is provided with a pair of clips, each clip being constructed in accordance with the features of any one of the preceding claims, the clips being provided at the top and bottom of the module.

8. A module according to claim 7, wherein the tool is substantially "U"-shaped, the base of the "U" forming a handle to enable extraction of the module from the main frame once the latching means has been released.

9. A clip for retaining a module in the form of a printed circuit board and a panel within a main frame of electronic equipment, said clip being constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.