GB2216590A - A system for fixing a transducer to a support body - Google Patents

Description

1 1 i fl. ?- j r-- r, g 0 A SYSTEM FOR FIXING A TRANSDUCER TO A SUPPORT

BODY The present invention relates to a system for fixing a transducer to a support body.

Purely by way of example, it is known, for controlling the temperature of the coolant liquid of an engine, to fit a radiator tank with a transducer constituted by a thermometer switch, more briefly termed a temperature switch. The installation is generally effected by forming a through hole in a side wall of the tank and subsequently introducing through the hole a sensitive portion of the temperature switch.

Currently the thermometer switch is fixed to the wall of the tank by utilising a resilient element comprising a central portion which rests on one face of the temperature switch and two lateral portions which have respective toothed projections which snap-engage a respective tooth extending from the wall of the tank.

This resilient element constitutes a separate piece which must be engaged on the transducer body to allow the fixing of this latter. it is evident that this operation does not lend itself well to automation in that it is necessary to have available two separate manipulator arms 2 with t heir respective movements well coordinated.

The object of the present invention in that of providing a system for fixing a transducer to a support body which allows the use of an automatic machine for this fixing.

According to the present invention there is provided a system for fixing a transducer to a wall, particularly the wall of a tank, characterized by the fact that it comprises at least two substantially C-shaped, counterposed resiliently deformable hook elements having a first end mechanically fixed to a central portion of the body of the said transducer and a second end adapted to cooperate with a respective tooth extending from the said wall by forming a bayonet coupling therewith.

For a better understanding of the present invention various preferred embodiments are now described, purely by way of non-limitative example and with reference to the attached drawings, in which:

Figure 1 is a sectional view of a transducer provided with a fixing system formed as a first embodiment of the invention; Figure 2 is a perspective view, on a reduced scale, of the transducer of Figure 1; and 1 1 3 1 Figures 3, 4, 5, 6 and 7 are perspective views of transducers provided with fixing systems formed as further embodiments of the invention.

An illustrated in Figure 1, a temperature switch, generally indicated with the reference numeral 1, is mounted within a through hole 2 formed in a wall 3 of a tank (not illustrated) by me& ns of an annular seal 4 and a fixing system 5 formed according to the principles of the present invention.

The characteristics of the temperature switch 1 are known and only the main parts thereof will be indicated in detail hereinafter.

in particular, the temperature switch 1 has a cylindrical central body 7 from the upper face of which extends a substantially elliptical body 8 within which are installed two blade-like pins 9 connected to two contacts 10 which are located within the interior of a chamber formed in the central body 7 and one of which is carried by a resilient blade 11.

On the side opposite that where the body 8 is formed the transducer 1 has a bulb 12 which, in use, extends through the hole 2 into the interior of the chamber.

4 The bulb 12 comprises a cup-shape metal body 13 having a first cylindrical portion 14 on the bottom wall 15 of which In aeated a heat sensitive membrane 16 cooperating with a ve rtical push rod 17, and a second cylindrical portion 18 of grea. ter diameter which is fitted over the central body 7. Within the interior of the first portion 14 is installed a cylindrical body 21 for guiding the push rod 17 one end of which acts, in use, on the said resilient blade 11.

The second portion 18 of the bulb 12 has an annular bottom wall 22 against which the lower face of the body 7 engages and an upper edge 23 folded over the peripheral edge of the upper face of the body 7, which is slightly conical. Between the portions 14 and 18 there is further defined an annular shoulder 24 which acts to press the seal 4 onto an inner annular shoulder 25 around the hole -he 2 in such a way as to form a sealed coupling between temperature switch 1 and the well 3.

With particular reference to Figures 1 and 2, the fixing system 5 comprises two resiliently deformable metal blades 27 welded at one end onto the portion 18 of the body 13 and folded at the opposite end into a C-shape to form a bayonet coupling with two teeth 28 extending from the wall 3.

The blades 27 are located in diametrically opposite positions from one another and have a first section 31 orthogonal to the wall 3 and welded along the portion 16, a second section 32 parallel to the wall 3, and a third section 33 which extends orthogonally towards the wall 3 and which has an end bent up towards the portion 18 parallel to the wall 3. This end defines a tooth 34 which forms a bayonet-like coupling with the tooth 28, which is formed on the outer surface of an annular projection 35 coaxial with the hole 2 and extending from the wall 3.

As illustrated in Figure 3, a fixing system formed in a different manner from the system 5 is indicated with the reference numeral 31. The difference between this system 31 and the other systems which are described hereinafter lies in the different formation of the fixing and/or of the support of the blades 27, which remain substantially the same, on the portion 18 of the body 13.

The system 37 has a flat annular band 38 from which the blades 27 extend, and which engages the bottom wall 22 against which it is pressed by two resilient tongues 39 snap-hooked onto the upper face of the body 7. in 6 particular, upwardly from the perimetral edge of the band 38 extend two tongues 39 &eh of which has an and bent over to define a tooth 40 snapengaging a recess formed on the upper face of the body 7. The tongues 39 are diametrically opposed and offset by 90' with respect to the blades 27 the first sections 31 of which extend from the same perimetral edge of the band 38.

In Figure 4 there is shown a fixing system generally indicated 42 comprising a cylindrical band 43 fitted around the portion 18 and from which extend blades 21. The band 43 is fixed to the body 13 by a plurality of resilient tongues at least three of which extend upwardly and are indicated 44 and at least three of which extend downwardly and are indicated 45. Each tongue 44, 45 has an end bent over to define a respective tooth 46a, 46b; each tooth 46a of the upper tongues 44 snap-engages a recess 47 formed in the upper face of the body 7. The teeth 46b of the lower tongues 45 on the other hand engage against the lower wall 22 of the portion 18.

The tongues 44, 45 are uniformly distributed around the band 43: in particular, the tongues 45 are offset by 60c with respect to the tongues 44.

The blades 27 extend from the lower end of the band 43, and in this case the blades 27 do not have a first section 31. Between the band 43 and the section 32 of the blades 27 is formed a respective bridge 48 derived from a punching operation thereon. These bridges 48 constitute ribs which permit selection of the resilience of the blade 27 in dependence on their folding.

As illustrated in Figure 5, there is shown a fixing system generally indicated with the reference numeral 51, which is similar to the system 37 in that it has a band 38 from which the blades 27 extend. The single difference between the systems 51 and 37 lies in the fact that the system 51 has no tongues 39 in that the fixing of the band 38 to the portion 18 is achieved in this case by welding (not illustrated).

As illustrated in Figure 6, a fixing system similar to the system 42 is generally indicated with the reference numeral 53, this is similar in that it also has a band 43 fitted around the portion 18 from which the blades 27 extend. As distinct from the system 42 the system, 53 has no tongues 44 and 45 in that the fixing between the band 43 and the portion 18 is achieved, in a manner not illustrated, by welding. In the system 53 the bridges 48 and recesses 47 are not provided.

An illustrated in Figure 7 there is shown a fixing system generally indicated with the reference numeral 55 in which the blades 27 are supported by the portion 18 of the body 13, which is made of plastics material. In particular, the blade 27 has a part of the section 32 and all of the section 31 embedded in the portion 18. Upwardly from the section 13 and coplanar with thin extends a resilient tongue 57 one end of which projects axially from the sleeve 56. This end of the tongue 57 is then bent over defining a tooth 58 which snap-engages a recess 59 formed on the upper face of the body 7.

The body 13, the blades 27, the bands 38 and 43, and the tongues 39, 44, 45 and 57 are made of sufficiently robust is metal material, such as for example steel; the bodies 7, 8 and 21 are on the other hand made of a plastics material.

The fixing systems described above in relation to the mounting of the temperature switch 1 onto the wall 3 of the tank are equivalent to one another. In fact, it is sufficient to introduce into the hole 2 of the wall 3 first the seal 4 and subsequently the bulb 12. At this point the whole temperature switch 1 in turned until bayonet coupling between the blades 27 and the teeth 28 is achieved. All the operations described can be 9 effected automatically by a single arm of an operating machine, with all the advantages which this obtains in relation above all to the time taken for assembly, and the simplicity thereof.

The fixing systems described above ar of simple construction and differ from one another only In the manner in which the blades 21 are securely mechanically fixed to the temperature switch 1. It is to be noted that the attachment of the blades 27 can also be achieved by means of an automatic machine thereby further reducing the cost of the assembly of the temperature switch. Finally, it is to be noted that with the fixing systems indicated above a secure and robust attachment to the wall 3 of the tank in achieved.

Finally, it is clear that the fixing systems described and illustrated here can have modifications and variations introduced thereto without by this departing from the protective ambit of the present invention.

In particular, it appears evident that the application of the fixing systems to a transducer such as a temperature switch is not to be considered limitative, it being in fact possibl e to utilise such systems for engaging any other type of transducer onto a pierced wall.

Moreover, for the systems 5, 51 and 53 which have no snap-engagement elements (tongues) to the temperature switch 1 it is possible to form on these latter references for positioning these systems at a predetermined angle. Finally, it in evident that there could be more than two hook elements.

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Claims (1)

11 CLAIMS

1. A system for fixing a transducer (1) to-a wall (3), particularly the wall of a reservoir, characterized by 5 the fact that it comprises at least two substantially C-shaped, counterposed, resiliently deformable hook elements (27) having a first end (31, 32) mechanically fixed to a central portion (7, 18) of the body of the said transducer (1) and a second end (34) adapted to cooperate to form a bayonet-type coupling with a respective tooth (28) extending from the said wall (3).

2. A fixing system according to Claim 1, characterised by the fact that the said hook elements each comprise a respective metal blade (27) having a first section (32) parallel to the said wall (3) and a second section (33) orthogonal to this latter and along which the maid second end (34) is defined.

3. A fixing system according to Claim 2, characterized by the fact that the said central portion (7) is fitted between a cylindrical metal body (18) having an annular wall (22) on which the lower face of the maid central portion (7) engages, and an upper edge (23) bent onto the upper face of the said central portion (7).

12 4. A fixing system according to Claim 3, characterized by the fact that orthogonally from the said first section (32) extends a third section (31) mechanically fixed to the maid metal body (18) by means of a welding operation.

5. A fixing system according to Claim 3, characterized by the fact that the said blades (27) extend from a band (38) or (43) mechanically fixed to the said metal body (18).

6. A fixing system according to Claim 5, characterized by the fact that the said band (38) adheres to the maid bottom wall (22) and is retained by at least two first counterposed resiliently deformable tongues (39) extending from the said band (38) and adapted to snap-engage with their end teeth (40) a recess formed on the upper face of the said central portion (7).

7. A fixing system according to Claim 5, characterised by the fact that the said band (38) adheres onto the said bottom wall (22) and is fixed to this latter by means of a welding operation.

8. A fixing system according to Claim 6 or Claim 7, characterised by the fact that upwardly from the perimetral edge of the said band (38) extends a plate 4 13 (31) from which the said blade (21) extends and in particular the said first section (32) thereof.

9. A fixing system according to Claim 5, characterized by the fact that the said Land (43) ic fitted cuto the said metal body (18) and fixed to this by means of at least two second resiliently deformable tongues (14) extending upwardly therefrom and adapted to snap- engage with their and teeth (46) a reispective recess (47) formed on the upper face of the said central portion (7), and by means of at least two third resiliently deformable tongues (45) having a bent end (46) which adheres onto the said bottom wall (22).

10. A fixing system according to Claim 5, characterised by the fact that the said band (43) is fitted onto the said metal body (18) and secured to this by means of a welding operation.

11. A fixing system according to Claim 3, characterised by the fact that the said hook elements (27) have their said first end (31, 32) partially embedded in a lower central portion (18) of the body of the said transducer; the said hook elements (27) having a respective fourth resiliently deformable tongue (57) which extends upwardly beyond the said central portion (18) and has an end tooth 14 (58) adapted to snap-engage a recess (59) formed on the upper face of an upper central portion (7) of the body of the said transducer (1).

12. A fixing system according to any preceding Claim, characterized by the fact that the said transducer (1) is a thermostat switch and in that the said reservoir is a collecting tank for coolant liquid of an engine of a vehicle. 10 13. A system for fixing a transducer to a wall as described and illustrated with reference to the attached drawings.

Published 1989 atThe Patent Office, StateHouse. 68.71 EDgh Holborn, London WC IR 4TP. Further copies maybe obteJnadfrom The Patent Omee. Was Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1/87