GB2228289A

GB2228289A - Clip fastening for control device

Info

Publication number: GB2228289A
Application number: GB9000931A
Authority: GB
Inventors: Ian Stuart Petherick; Frederick Valentine Cousins
Original assignee: Diamond H Controls Ltd
Current assignee: Diamond H Controls Ltd
Priority date: 1989-02-15
Filing date: 1990-01-16
Publication date: 1990-08-22
Also published as: GB8903442D0; GB9000931D0

Abstract

A means of clip-fixing a control device to the mounting panel of an appliance in a manner which provides a secure and rigid fixing without the use of nuts or screws. A clip (1) is formed with sloping surfaces (6) which are squeezed through an aperture in the mounting panel and then spring outwards to lock the control device into position. The profile of the clip (1) engages the profile of the mounting hole (10) to avoid rotation and a space (4) between the clip and mounting face (2) of the control device permits resilient flexing of the clip. Alternative forms of clips are described requiring various shapes of holes in the mounting panel of the appliance, such as rectangular, circular and T-shaped. <IMAGE>

Description

CONTROL DEVICE CONTROL DEWICE This specification relates to control deuices for domestic appliances and to the way such control deuices are mounted and fixed to the appliances. In particular, but not exclusively, the invention is applicable to the fixing of energy regulators, thermostats, and switches to the control panels of cooking appliances.

There are two fixing methods in common use, both of which incorporate threaded fixings and necessitate the provision of three holes in the control panel for each control deuice.

In one commonly used method, the mounting face of the control device carries a threaded bush and two pegs.

The operating spindle of the control deuice passes through the axis of the threaded bush. A nut retains the threaded bush in the central hole of the panel, and the two pegs engage the other two holes to ensure non rotation of the control device.

The other commonly used method incorporates two tapped holes within the mounting face of the control deuice, usually at a spacing of 28mm, and spaced symmetrically about the spindle. Screws engage the two tapped holes to retain the control device on the control panel, and the operating spindle passes through the centre hole.

Both of these fixing methods prouide very satisfactory fixing. The fixing is robust, secure, and rigid, and ensures electrical continuity (to international standards) between the panel and the control device when required for earthing purposes.

These well established fixing methods suffer from the disadvantage that the appliance manufacturer has the relatiuely expensive operation of supplying a multiplicity of washers, nuts or screws; handling these components is also time consuming. Also both front and rear surfaces of the mounting panel must be accessible at the time of installing the controls; this can be inconuenient on a production line.

It is an object of this invention to prouide a method of fixing which eliminates the need for the appliance manufacturer to handle a multiplicity of washers, nuts or screws. It is a further object to auoid the need to have the front face of the mounting panel accessible at the time of assembly.

n further object of this invention is to provide robust, secure, and rigid fixing and electrical continuity comparable with that provided by screw fixing.

Energy regulators, thermostats, and switches mounted on the control panels of cooking appliances have to withstand arduous tests to ensure their fitness for domestic use. Typical requirements are continuous use at 120C, adequate earthing of exposed metal parts by testing with a simulated fault current of 75A maintained for 5 minutes. Various mechanical tests couer push-on and pull-off forces for operating dials, impact tests on operating spindles, and forces involved during the assembly and dismantling of various snap-on connectors which form electrical connections, Test requirements are detailed in many national and international specifications, of which the following are typical: bus3456: Part 101: 1978 Safety of household and similar electrical applicances.

BS3955: 1986 Electrical controls for household and similar general purposes.

According to the invention there is provided a control device having a protruding spring clip integral therewith or attached thereto, a space being formed between the clip and a mounting face (of the control deuice) to permit resilient flexing of the clip, the spring clip being shaped so that it can be pushed, from the rear of a panel, into an aperture in that panel and will spring outwardly after hauing been pushed through the aperture to engage the front of the panel, the clip then providing fixing and electrical continuity between the control device and the panel.

The invention prouides a clip fixing arrangement, the efficiency of which is largely independent of the skill of the assembly operator euen though the front surface of the mounting panel may not be accessible at the time of assembly.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings of which: Figure 1 is a front uiew of a clip secured to the mounting face of a control deuice (details of the control device are not shown); Figure 2 is a side vew of the clip shown in Figure 1; Figure 3 is an end uiew of the clip shown in Figure 1 (this is partly in cross section, corresponding to the arrows in Figure 1); Figure 4 shows a typical cutout in the mounting panel of the appliance, to receive the control device of Figure 1 (the two round holes are not required for this invention); Figure 5 is a perspective view of a spring member formed from sheet rnetal and forming part of a further embodiment;; Figure 6 shows the spring of Figure 5 fixed to the front of a control device and mounted onto a control panel; Figure 7 shows the three apertures needed in the control panel required for use with the spring of Figure 5; Figure 8R shows an alternative clip member in which the retaining portions are circularly disposed (Figures 8B and 8C show sections on lines C-C and B-B respectiuely in Figure 8fi); Figure 9 shows the three apertures required in the mounting panel to use with the clip of Figure 8Q; Figure 10 shows the end uiew of a further alternative clip member, partly in cross section along line F-F of Figure 11; Figure 11 shows the front view of the clip of Figure 10 (for clarity the control device is not shown);; Figure 12 shows the side view of the clip of Figure 10; Figure 13 shows the blank shape of the clip of Figures 10, 11 and 12; Figure 14 shows the holes required in the mounting panel to receive the clip of Figures 10, 11, 12 and 13, and shows part of the clip in position; Figure 15A shows an end view of the clip in another embodiment (Figure 15B is a view on arrow D of Figure 15fi); Figure 16 shows the holes required in the mounting panel to receive the clip of Figure 15n; Figure 17 shows a front uiew of another alternative clip; and Figure 184 shows a view similar to Figure 3 of a further modification (Figure 18B is a uiew in the direction of arrow E of Figure 18n).

Referring to Figures 1, 2, 3, the clip 1 is secured to the mounting face 2 of the control device by screws or rivets in the embossed countersinks 3. The embossed countersinks 3 produce a space 4 between the clip 1 and mounting face 2 to permit resilient flexing of the clip. The clip 1 is manufactured from resilient material such as thin spring steel.

Two side portions 5 of the clip are bent upwards and inwards to produce two sloping surfaces 6 and four sharply defined corners 7. The four corners 8 of the clip are formed forwards. Note that for clarity the formed corners 8 are not shown in Figure 3. Windows in the side portions 5 produce sides 9 on the sloping surfaces 6. The dimension produced between sides 9 and the tips of the corners 8 is smaller than the thickness of the mounting panel on the appliance on which the control device will be installed. The clip 1 becomes an integral part of the control deuice, being assembled to the control device by the manufacturer of the control device.

Figure 4 shows the generally rectangular hole 10 which the appliance manufacturer needs to prouide in the mounting plate to receive the control deuice. The dimensions of this hole are such that the four corners 11 will receive the four corners 7 of the clip 1. One such hole is needed for each control device.

When fitting a control device to the mounting panel in the appliance, the control device complete with its clip 1 is pressed by hand towards the appropriate hole, 10.

Under pressure, the sloping surfaces 6 are squeezed through the hole 10. Having passed through the hole 10, the sides 9 spring outwards and engage the front surface of the mounting panel. fit the same time the corners 8 engage the rear surface of the mounting panel. When the clip 1 is fully engaged with the mounting panel a positiue fit is ensured because the panel thickness is greater than the free dimension between sides 9 and the formed corners 8. This ensures rigidity of fixing and earth continuity for the control device, and rotation is preuented by the fit of the corners 7 within the corners 11.

Because the sides 9 engage the front face of the mounting panel, the control deuice cannot be removed from the appliance without the use of a suitable tool.

In Figure 4 two round holes are shown which are not a feature of this invention. They are shown merely to illustrate that it is possible to include two holes for conuentional two screw fixing if it should be required for some reason.

The functions of the alternative construction shown in Figures 5, 6 and 7 will be clear from the figures.

The spring 12 is made from resilient material such as sheet spring steel, the spring has multiple V forms and includes formed grooues 13. n nut 14 may be used to secure the spring 12 to the control device 15. The control panel shown in Figure 7 is prouided with three apertures 16 and 17. The aperture 17 is large enough to clear the central area of spring 12 and nut 14.

During assembly of the control deuice to the control panel, pressure is applied to force the formed grooues 13 of spring 12 into engagement with the apertures 16.

The resulting assembly prouides a high degree of rigidity for the control device mounted upon the panel.

fill four corners of the spring 12 may be cut away as indicated by the shaded area 18. In this case the apertures 16 may be extended to include the chain-dotted areas 19. With this arrangement the end portions of spring 12 will lock into the aperture 16, 19 thereby improuing the fixing.

The application of the embodiment shown in Figures 8 and 9 is similar to that of Figures 1, 2, 3 and 4.

The clip 20 of Figure 8 is made from resilient material such as sheet spring steel and is assembled to become an integral part of the control device. Seueral sloping surfaces 6a are prouided. Six surfaces are illustrated, but any conuenient number may be utilized. 6b illustrates the shape of the blank before being formed to provide the sloping surface 6a and side 9a depicted by the section arrows fi of Figure 8fi. Two further limbs 21 are provided with formed end portions.

The mounting panel (Figure 9) has three holes. The central circular hole 22 receives the sloping surfaces 6a, and the two holes 23 receive, at the accepted standard spacing of 28mm, the formed ends of the limbs 21. Thus when fitting a control device to the mounting panel in the appliance, the control device complete with its clip 20 is pressed towards the holes 22, 23. Under pressure the sloping surfaces 6a ar squeezed through the hole 22, and hauing passed through the hole the sides 9a spring outwards and engage the front surface of the mounting panel. fit the same time the limbs 21 engage the holes 23 and press against the mounting panel. The limbs 21 prevent rotation of the control device and also ensure that a firm grip is provided by the sides 9a against the mounting panel.

It should be understood that, whilst a generally circular configuration is shown for the clip of Figure 8 and hole in the mounting panel of Figure 9, other configurations are not excluded.

The further embodiment shown in Figures 10, 11, 12, 13 and 14 is also similar to that shown in Figures 1, 2, 3 and 4.

The clip 24 is secured to the mounting face of the control (not shown) by screws or riuets in the embossed countersinks 3d; in the same way as shown for the embodiment in Figures 1, 2 and 3, the embossed countersinks 3d produce a space between the clip 24 and the mounting face of the control to permit resilient flexing of the clip. The clip 24 is manufactured from resilient material such as thin spring steel. The two side portions 25 of the clip are bent downwards in a channel formation to embrace the width of the control device. The side portions 25 are profiled as broad arrows in which the centre legs are shaped and formed to provide sloping surfaces 6d and sides 9d. These sloping surfaces and sides extend above the front surface of the clip 24. The four corners 8d of the clip are formed forwards.The dimension produced between the sides 9d and the tips of the corners 8d is smaller than the thickness of the mounting panel on the appliance on which the control device will be installed.

Figure 14 shows the three circular holes needed in the mounting panel of the appliance. Hole 26 clears the spindle of the control deuice (not shown) and holes 27 receive the retaining portions 28 of the clip 24. The holes 27 are of such a size that they circumscribe the profile of the retaining portions 28. When fitting a control device to the mounting panel in the appliance, the control device complete with clip 24 is pressed by hand towards the holes of Figure 14. Under pressure, the sloping surfaces 6d are squeezed through the holes 27, forcing apart the two retaining portions 28 until fully engaged. When the clip 24 is fully engaged with the mounting panel, the two retaining portions 28 spring back towards each other, and a secure grip is produced between the tips of the corners 8d and the sides 9d.

The alternative embodiment shown in Figures 15R, 15B, and 16 is very similar to that of Figures 10, 11, 12, 13 and 14.

In Figures 15X and 15B, the clip 24e has retaining portions 28e differing in shape from those of clip 24 with retaining portions 28, but the functions of these details are very similar. The retaining portions 28e are produced in T shapes. Bends in the T shapes produce sloping surfaces 6e and sides 9e. As shown in Figure 16, T shaped holes are required to receive the retaining portions 28e.

When fitting a control device to the mounting panel in the appliance, the control deuice complete with its clip 24e is pressed by hand towards the holes shown in Figure 16. Whilst the sloping surfaces 6e pass through the holes 29 they are forced outwards by edges 30, and when fully engaged the retaining portions spring back towards one another until the sides 9e lie in the positions indicated by the chain dashed lines 31 in Figure 16.

It should be understood that whilst it is not a feature of this invention, two holes at 28mm centres may be included in Figure 14 and Figure 16 to allow for conuentional two-screw fixing should it ever be required.

fi further alternative construction which is not illustrated in the figures is a form of bayonet fixing.

This alternative has practical limitations because of the complicated shapes needed on both the control device and on the mounting panel. n further limitation is that control devices could not be mounted tightly side by side because of the need to use a rotary motion during the bayonet fixing operation.

Figure 17 shows a uariant of the clip of Figure 1 in which the formed corners are prouided at the ends of respective protrusions 40 in the plane of the clip 1.

This provides additional resilience for the corners 8 so that the clip 1 can accept a greater uariation in the thickness of the mounting panel.

Figures 18 and 18B show a variation of the embodiment shown in Figure 3. In Figure 3 the clip is secured to mounting face 2 of the control device by screws or riuets in the embossed countersinks 3. In Figures 18R and 188 the screws or rivets are replaced by pegs 41 extending from the mounting face 2 which engage barbs 42 produced from the base portion of the mounting clip.

Spacers 43 are associated with pegs 41 to prouide a space 4 between the clip and the control device similar to that produced by the embossments 3 in Figure 3.

It will be clear that the details covered by Figures 18Q and 188 may be used to replace the riuets or screws and countersinks used in other embodiments.

It will also be clear that the equivalent of the space 4 may be achieved by allowing the base portion of the clip to extend beyond the portions which secure the clip to the mounting face of the control device.

Throughout this specification it will be understood that the rear surface of the mounting panel is the surface upon which the control devices are mounted, and will be contained within the completed appliance. The front surface will face outwards on the appliance.

The illustrated clips permit a control device to be secured to a mounting panel without requiring access to the front of the panel and by merely pressing the clip (when attached to the control deuice) into a hole in the mounting panel. This is useful when manual assembly methods are used and particularly useful for automatic assembly. Automatic assembly is normally impossible if access to the front of the panel is needed and a "pick and push" method made possible by the illustrated clips lends itself to automatic assembly.

The invention is not restricted to the prouision of a clip as a separate component which is secured to the mounting face of the control device. It will be clear that the clip may be produced as an integral part of the control device.

In summary, the illustrated clips provide the following advantages : - 1. n means of securing control deuices to mounting panels in which the control deuice carries a clip whereby secure fixing is achieued by pressing the clip into an aperture in the mounting panel without need for access to the front face of the panel at the time of fixing.

2. Remoual cannot be effected without the use of a tool 3. Security of the fixing is assured by the dimensions of the clip and so unaffected by the skill of the appliance assembly operator.

4. Electrical continuity is assured by the dimensions of the clip.

5. Non-rotation of the control device is assured by the fit of the clip within the profile of the aperture.

6. The properties of the aperture in the mounting panel lav room for the possibility to include conventional fixing of the control deuices by two screws.

Claims

1. n control deuice having a protruding spring clip integral therewith or attached thereto, a space being formed between the clip and a mounting face (of the control device) to permit resilient flexing of the clip, the spring clip being shaped so that it can be pushed, from the rear of a panel, into an aperture in that panel and will spring outwardly after having been pushed through the aperture to engage the front of the panel, the clip then providing fixing and electrical continuity between the control device and the panel.

2. n control device as claimed in claim 1, wherein the spring clip is fabricated from springy sheet material and is attached to the control device by screws or rivets passing through embossed countersunk portions of the spring clip thereby providing a space between the clip and the mounting face of the control deuice.

3. n control device as claimed in claim 1, wherein the spring clip is fabricated from springy sheet material and is attached to the control deuice by pegs extending from the mounting face, passing through respective apertures in the spring clip and engaged by barbs protruding from the spring clip, thereby providing a space between the clip and the mounting face of the control deuice.

4. n control deuice as claimed in claim 2 or claim 3, in which opposite side portions of the clip are bent away from the control device and towards each other to prouide two sloping surfaces intended to be engaged by the edges of the aperture in the panel.

5. fi spring clip as claimed in claim 4, wherein cuts are formed in each bent side portion to prouide in each sid portion a generally flat surface intended to be engaged by the corresponding edge of the aperture in the panel.

6. n control device according to claim 5, in which the spring clip is formed with sharply defined corners with the distance between the corners and the most rearward edges of the generally flat surfaces being less than the thickness of the intended mounting panel.

7. fi control device according to any of claims 1 to 3, wherein the spring clip is mounted on a protrusion on the control device and is at each end bent backwardly towards the control device, forwardly away from the control device beyond the protrusion and backwardly towards the control device to provide two protrubences of the clip at each end, the mounting panel being provided with a first aperture to receive the protrusion on the control deuice and second and third apertures on opposite sides of the first aperture to receive the protrubences on the spring clip, each protrubence on the spring clip being shaped so that when forced into the second or third apertures respectively it is held therein

8. n control device according to any of claims 1 to 3, in which the mounting panel is formed with a central aperture for a control spindle of the control device and first and second apertures on opposite sides of the central aperture and wherein the clip is formed with first and second projecting legs for engagement with the first and second apertures respectively, each leg being formed with an edge for engagement with an edge of the respective aperture, the edges being outwardly inclined as they extend away from the control deuice and being formed with an inner shoulder so that on engagement of the first and second legs with the first and second apertures the legs are forced outwardly until the shoulders pass the mounting panel and engage the front of the mounting panel.

9. n control deuice hauing a spring clip attached thereto for securing the control device to a mounting panel substantially as hereinbefore described with reference to the accompanying drawings.

10. n control device having a spring clip as claimed in any preceding claim, the control device being secured to a mounting panel of apparatus to be controlled.