GB1578682A - Fixing of plates to a support or foundation - Google Patents

Description

(54) FIXING OF PLATES TO A SUPPORT OR FOUNDATION (71) We, DORMAN SMITH SWITCHGEAR LIMITED, a British Company, of Atherton Works, Blackpool Road, Preston, Lancashire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns the fixing of metal plates to a support or foundation so as to stand up from said support or foundation, for example, the fixing of metal side plates, for the mounting thereon of other components, in the casing of a moulded-case electric circuit breaker.

An object of the present invention is to provide a method of making such fixings which is particularly convenient, and relatively easy to carry into effect, requiring no particular skill, and which serves to ensure tight, firm and reliable anchorage of the plates to the support or foundation material.

With this object in view the present invention provides a method of securing a plate to a support or foundation, so as to stand up from said support or foundation, which comprises inserting into an opening in the support or foundation from one side of the latter, a substantially flat T-shaped tongue projecting from and integral with an edge of the plate, and thereafter so twisting the cross-bar and upright of the T-shaped tongue that the crossbar is caused to overlie and engage a thrust surface facing away from the said one side of the support or foundation and that the effective length of the upright of the Tshaped tongue is shortened to such an extent that the plate is drawn into tight and secure abutment against the said one side of the support or foundation.

The plate may, of coures, be formed with a plurality of T-shaped tongues, each tongue being inserted into an opening and being similarly twisted to provide an anchorage of the plate to the support or foundation.

The arrangement may, of course, be such that the or each T-shaped tongue projects right through the support or foundation, so that the other side of the support foundation, remote from said one side, constitutes the thrust surface.

In the latter instance, the twisted crossbars of the tongue will appear as projections or protrusions at the said other side of the support or foundation. To avoid these projections, each opening is preferably stepped to provide therein a shoulder which constitutes the thrust surface and which is so positioned in the opening that the cross-bar of the associated tongue does not protrude from the opening.

To prevent the or each cross-bar of the T biting into the material of the support or foundation, a washer is conveniently applied over each tongue before its cross-bar is twisted.

The invention is particularly applicable to electrical components having plastics bodies or casings requiring mounting plates to be assembled therein, in which event the body or casing constitutes the support or foundation to which the mounting plate is or mounting plates are fixed in accordance with the invention.

The invention further includes an assembly comprising a support or foundation having an upstanding plate fixed thereto by the method aforesaid; in a practical instance the support or foundation may, therefore, be a body or casing of an electrical component (such as a circuit breaker) and the plate may be a mounting plate permitting other parts to be mounted in or on the body or casing.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a part-sectional side elevation illustrating the base part of a moulded case circuit breaker having side plates secured thereto in accordance with the method of the invention; Fig. 2 is a plan view corresponding to Fig. 1; Fig. 3 is an enlarged fragmentary section taken as indicated by the line 3-3 of Fig. 2; Fig. 4 is an enlarged, part-sectional fragmentary detail illustrating part of one of the side plates of the arrangement of Figs. 1 and 2 about to be assembled to the base part; Fig. 5 is an underneath plan showing the underneath configuration of the opening in the base part when viewed as indicated by the arrow 5 of Fig. 4;; Fig. 6 is a view comparable with Fig. 4 illustrating the side plate inserted in place and secured in position; and Fig. 7 is a view, comparable with Fig. 4, but showing an underneath view corresponding to Fig. 6.

Referring firstly to Figs. 1 to 3 of the drawings, these illustrate the use of the method of the invention for securing two side plates 10 to respective supports or foundations constituted by ledges 11 upstanding from the bottom 12 of a base part 13 of the casing of a moulded-case electric circuit breaker, of which the other parts are not shown since they are not necessary for the understanding of the invention. The base part 13 of the casing has sidewalls 14 alongside which the side plates 10 are disposed, and these side plates 10 serve for the mounting therebetween of components (not shown) of the mechanism of the circuit breaker.

Each side plate 10 is appropriately shaped and apertured, particularly, but not exclusively, in its upper portion 15, for the mounting of the components as just discussed, and is formed with a substantially linear lower edge 16 for resting down on the respective ledge 11. For securing each plate 10 in its respective position upstanding from its ledge 11, the plate 10 is formed with two integral tongues 17 projecting from the lower edge 16. As can be seen more particularly from Fig. 4, each said tongue 17 is of Tshaped configuration (upside down in the illustrated disposition) having an upright portion 18 and a cross-bar 19.

Complementary to these tongues 17 respective openings 20 are provided through the ledges 11. Each such opening 20 is stepped to provide a shoulder as at 21 so that the opening 20 comprises a narrow portion 22 of axial length slightly shorter than the lengths of the upright portions 18 of the tongues 17 in their initial conditions as shown in Fig. 4 and having diametrically-disposed lateral recesses 23, so that upon insertion of the respective tongue 17 into its opening 20, the cross-bar 19 will pass through the narrow portion 22 and the recesses 23 to come to rest with the upright portion 18 accommodated largely within the narrow portion 22 and the cross-bar 19 accommodated within a wider portion 24 of the opening 20.This wider portion 24 is of depth greater than the corresponding depth of the cross-bar 19 of thS tongue 17 so that the cross-bar 19 is accommodated wholly within the wider portion 24 of the opening 20 and does not protrude at the bottom surface of the base portion 13 of the casing.

Once the plate 10 has been put in position by inserting the tongues 17 into their openings 20, a respective slotted washer 25, whose hole 26 corresponds to the shape of the narrow opening portion 22 plus its recesses 23 as visible in Fig. 5, is slipped onto each said tongue 17 so as to abut against the respective shoulder 21 at a disposition in which it will not obstruct twisting of the cross-bar 19 of the tongue 17.

The plates 10 having been so located in position, wherein they are upstanding from their supports or foundations provided by their respective ledges 11, each is now secured firmly in position twisting the respective tongues 17. This is effected, for each tongue 17, by inserting an appropriate slotted tool (not shown) into the wider portion 24 of the opening 20 so as to engage onto the cross-bar 19 of the tongue 17 and then turning the tool about an axis corresponding approximately to the longitudinal centre line of the upright portion 18 of the tongue 17.

As a result, the projecting lobes of the crossbar 19 of the T are brought into respective positions overlying the washer 25 and pressing through the washer 25 against the shoulder 21 which constitutes a thrust surface, facing away from the upper surface of the ledge 11, against which the lower edge 16 of the plate 10 abuts.

It will readily be understood that the twisting of the cross-bar 19 of the T is accompanied by corresponding twisting of the upright portion 18 and has the effect of progressively reducing the effective length of the upright portion 18 with the result that the cross-bar 19 thrusts tightly against the shoulder 21 (being prevented from biting into the material of the shoulder 21 by the washer 25) and thereby clamps the plate 10 firmly to the ledge 11.

Practical tests show that particularly reliable fastening can be achieved in this way, especially if use is made of a torque wrench or similar tool to ensure that a predetermined minimum of twisting of the tongue 17 is effected, and that overtwisting is avoided.

A particular advantage of the method of the invention lies in its ability to accommodate small variations in thickness of the support or foundation to which the plate is secured.

For instance, in the illustrated example, the base of the circuit breaker casing might vary by as much as 0.010" and such a variation can readily be accommodated by the fixing which will accommodate, for instance, variations of up to 0.015".

Naturally the invention is not confined to the precise details of the foregoing example, and variations may be made thereto. Thus, there may be cases where a single tongue can be used to secure a plate to its support or foundation, and other cases where more than two of the tongues are necessary, according to practical requirements. Of course, the method of the invention is not restricted to the fixing of side plates in circuit breakers and can be used in any practical environment where a plate is required to be secured to a support or foundation of any structural material, such as metal, plastics or wood so as to stand up from the support or foundation.

WHAT WE CLAIM IS: 1. A method of securing a plate to a support or foundation, so as to stand up from said support or foundation, which comprises inserting into an opening in the support or foundation from one side of the latter, a substantially flat T-shaped tongue projecting from and integral with an edge of the plate, and thereafter so twisting the cross-bar and upright of the T-shaped tongue that the crossbar is caused to overlie and engage a thrust surface facing away from the said one side of the support or foundation and that the effective length of the upright of the Tshaped tongue is shortened to such an extent that the plate is drawn into tight and secure abutment against the said one side of the support of the foundation.

2. A method as claimed in Claim 1, wherein the plate is formed with a plurality of Tshaped tongues, each tongue being inserted into an opening and being similarly twisted to provide an anchorage of the plate to the support or foundation.

3. A method as claimed in Claim 1 or 2, wherein the or each T-shaped tongue projects right through the support or foundation.

4. A method as claimed in Claim 1 or 2, wherein the or each opening is stepped to provide therein a shoulder which constitutes said thrust surface and which is so positioned in the opening that the cross-bar of the associated tongue does not protrude from the opening.

5. A method as claimed in any preceding Claim, wherein a washer is provided over the or each tongue to abut against the thrust surface, before the tongue is twisted.

6. A method as claimed in any preceding Claim, wherein the or each plate is a mounting plate of an electric circuit breaker and the or each support or foundation is provided by a part of a casing of the circuit breaker.

7. A method as claimed in Claim 6, wherein the or each foundation is provided by a ledge upstanding from the bottom of a base part of the circuit breaker casing 8. A method of securing a plate to a support or foundation substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. An assembly comprising a support or foundation having an upstanding plate fixed thereto by the method of any preceding

Claims (1)

1. claim.

   10. An assembly as claimed in Claim 9, the support or foundation being a part of the body of the casing, and the plate being a mounting plate permitting other parts to be mounted in the body or casing.

   11. An assembly as claimed in Claim 9 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.