GB2324378A

GB2324378A - Attaching a sensor to a housing

Info

Publication number: GB2324378A
Application number: GB9807927A
Authority: GB
Inventors: Ernst-August Meyer; Ulrich Janietz
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1997-04-14
Filing date: 1998-04-14
Publication date: 1998-10-21
Anticipated expiration: 2018-04-14
Also published as: FR2762086B1; DE19716736C2; FR2762086A1; SE9801162D0; GB9807927D0; GB2324378B; SE9801162L; DE19716736A1

Abstract

A means for attaching a sensor 7 to an elongate housing 1, especially a housing for linear drives, is described. The housing 1 has on its outer surface at least one longitudinally extending clamping groove (3, fig 1) provided with a groove flank 6 which narrows the groove width towards the groove opening, it being possible to fasten at least one sensor 7 to said groove flank 6 by means of an attaching means. A groove 16 or surface arranged coaxially to the axis of symmetry of the sensor extends in parallel with and adjacent to the clamping groove (3, fig 1) and supports respectively within it or on it a screw 9 associated with the sensor, by means of which screw 9 at least one partial surface of the sensor may be pressed under the bevelled groove flank 6 when the screw is tightened, in such a way that a frictional and form-fitting connection is formed between the clamping groove (3, fig 1) and the sensor 7.

Description

2324378 MEANS FOR ATTACHING SENSOR The invention relates to means for

attaching a sensor to an elongate housing via at least one longitudinally extending clamping groove on the housing outer surface.

A sensor attaching means of this type is known for example from the product catalogue "Knowhow in Pneumatik" ("Know-how in Pneumatics") published by Mannesmann Rexroth Pneumatik GmbH (11/93, pages 1.004 and 1. 005). The sensor attaching means has a dovetailed clamping groove extending in the longitudinal direction along the housing of a pneumatic cylinder. The clamping groove serves to accommodate attaching means for one or more sensors. The sensors serve as position sensors, their role being to detect the position of the piston inside the pneumatic cylinder. The sensors may be attached in any position along the dovetailed clamping groove. The requisite sensor attaching means therefor may be found, for example, in data sheet 2.90.025 produced by Hoerbiger Automatisierungstechnik and is of multi-part construction. The dovetailed attaching component may be expanded by means of a screw to f ix the sensor in the clamping groove. However, this type of sensor attaching means has the disadvantage that the sensor always has to he inserted into the dovetailed clamping groove from the side. Direct insertion from above is impossible. Moreover, the sensor projects a long way from the housing surface, so that this open arrangement entails the risk of damage to and contamination of the sensor as well as its attaching means.

2 German Patent 41 27 204 proposes a protected arrangement of the sensor. A plurality of sensors and their signal cables are accommodated fully in a separate housing extending in the longitudinal direction of the linear drive and attached thereto. However, this solution requires a very large amount of space, and the overall dimensions of the linear drive are increased considerably.

German Application 44 08 639, therefore proposes to accommodate sensors wholly inside a groove in the housing of a linear drive. The groove is closed by a cover strip. As a result, the surface of the housing is smooth and its overall dimensions are not increased. Furthermore, the risk of damage to and contamination of the sensors is avoided. The disadvantage of this arrangement lies in the fact that a separate groove has to be provided for each sensor, because otherwise accommodation of the signal cable coming from the sensor would be obstructed.

European Patent Application 0 724 268 proposes that a groove be so shaped that several sensors with the associated signal cables may be accommodated in each groove. Here too, the groove is closed with a cover, such that a smooth closed overall housing surface is obtained. However, this solution has the disadvantage - as do the above-mentioned solutions - that the sensor attaching grooves are arranged in the middle of the side faces of the housing, which makes it necessary for the housing to have a relatively large wall thickness. This is particular so in the case of a conventional linear drive 3 with rectangular external cross section and circular internal cross section. In addition to increased weight, this also causes increased material consumption. Moreover, a relatively complex mounting procedure is required to accommodate several sensors in one groove. When sensors are being mounted, they always have to be inserted into the groove from the side. Then the signal cable has to be laid in the duct provided therefor. Finally, a cover strip for covering the groove between the sensors has to be cut to correspond to the sensor spacing and inserted. Another disadvantage is the fact that, when the sensor position is altered - for example as a result of adaptation of a different type of use - new cover strips have always to be provided to cover the groove, since they cannot be reused once the sensor position has been altered.

Therefore, the problem on which the invention is based is that of providing a solution to the problem of sensor attachment which on the one hand enables protected accommodation of sensors on a housing and on the other hand ensures simple mounting of the sensors as well as great flexibility of use.

A means f or attaching at least one sensor to an elongate housing in accordance with the invention comprises at least one longitudinally extending clamping groove provided on the housing outer surface, the clamping groove having a groove flank which narrows the groove width towards the groove opening, and a groove or surface 4 extending coaxially to the axis of symmetry of the sensor in parallel with and adjacent to the clamping groove and supporting respectively within it, or on it, a screw associated with the sensor, by means of which screw at least one surface portion of the sensor may be pressed under the groove flank when the screw is tightened, in such a way that a frictional and formfitting connection is formed between the clamping groove and the sensor.

The invention provides an arrangement in which a groove or surface arranged coaxially to the axis of symmetry of the sensor extends in parallel with and adjacent to the clamping groove and supports respectively within it or on it a screw associated with the sensor. At least one surface portion of the sensor may be pressed under the bevelled groove f lank in such a way that a frictional and formfitting connection is formed between the clamping groove and the sensor. When the screw is loose, the sensor is inserted into the clamping groove, which is provided with at least one bevelled portion in the manner of a dovetail guide. By tightening the screw, the sensor is then pressed against the groove flank, such that it is secured immovably. Since the form-fitting connection between sensor and clamping groove is effected only when the screw is tightened, the sensor may always be inserted into the clamping groove from above. The clamping principle according to the invention combines a frictional connection as a result of tightening of the screw against the sensor with the form-fitting connection against the bevelled groove flank. Thus, the sensor may be held immovably in the clamping groove.

Preferably the clamping groove is in the area of the side edges of the housing which is particularly useful in the case of standard housings for linear drives. Their conventional cross section results in build-up of material in the region of the side edges. This material build-up produced by the basic shape is used by extending the clamping grooves in this area. In this way, it is possible for the linear drive to have a small overall material thickness.

Suitably the sensors and of their signal cables are covered by the angular cover strip which provides a smooth outer housing profile. In this way, damage to and contamination of the sensors is effectively prevented. In the case of a linear drive, the standard dimensions of the housing may be maintained despite the sensors. Owing to its angular construction, the angular cover strip may be fitted particularly easily on the housing. Great flexibility of use is also achieved for this arrangement in that the position of the sensor may be altered as desired, the angular cover strip always being reusable.

The angular cover strip preferably consists of transparent plastics material, so that the position of the sensors is always visible from outside without removal of the angular cover strip.

Below the angular cover strip it is possible to arrange clamping grooves, preferably adjoining each other 6 in pairs, in the area of at least one side edge. Preferably the axes of symmetry of the sensors attached to the clamping groove pairs extend at right angles or in the form of a V. This measure enables two clamping grooves to be arranged in particularly space-saving manner at a side edge of the housing.

The invention will now be further described by way of example with reference to the accompanying drawings in which:

Fig. 1 is a perspective view of the sensor attaching means for a linear drive, and, Fig. attaching means.

Fig. 1 shows the housing 1 of a linear drive in the form of a pneumatic cylinder. Two clamping grooves 3, 31 extend along the housing 1 in the area of two opposing side edges 2, 21 respectively. Each clamping groove 3, 31 comprises, as shown in Figure 2, a groove bottom 4, 41 as well as one groove flank 5, 51 arranged at right angles thereto and a second, bevelled groove flank 6, 61 extending at an angle of approximately 800 to the groove bottom 4, 4'. The screw 9, 91 of a sensor 7, 71 rests in this clamping groove 3, 31 in associated grooves 16, 161.

The sensor has a bevelled portion 10, 101 corresponding to the bevelled groove flank 6, 6'. It is also possible to provide the sensor with two bevelled portions corresponding to the bevelled groove flank, such that either bevelled portion may be used to attach the 2 is an enlarged front view of the sensor 7 sensor 7, 71 in a clamping groove 3, 31.

A signal line 11, 111 extends from the sensor 7, 71. The sensors 7, 71 and their signal cables 11, 111 are covered by an angular cover strip 12. The signal cables 11, ill pass through openings in the lid of the linear drive. The angular cover strip 12 is conformed in shape to the basic external shape of the housing 1, such that a smooth overall outer housing surface is produced. The angular cover strip 12 is connected with the housing 1 by a snap connection in two retaining grooves 13, 131 extending in parallel with each other. This snap connection enables the angular cover strip 12 to be easily detached from the housing 1. To ease such detachment, the angular cover strip 12 may comprise a projection 14 formed on a longitudinal edge thereof. The angular cover strip 12 consisting of transparent plastics material permits viewing of the position of the sensors 7, 7' without its being necessary to remove the cover strip 12.

Owing to the V-shaped arrangement of the lines of symmetry 15, 151 of the sensors 7, 71, a free space is produced therebetween which permits the provision of a longitudinal screw (not shown in the Figures) which enables attachment of the front-end cylinder lid to the housing 1.

The screw 9, 91 takes the form of a setscrew and is held in the sensor. It has a screw slot 17 in its end face. The thread is designated 18. By turning the screw 9, 91, which rests at the bottom of the groove 16, 161, 8 the distance between the bevelled portion 10, 10' of the sensor and the bevelled groove flank 6, 6' is altered, i.e. the sensor is clamped securely.

An optional additional pressure plate is designated 8, 81.

Through appropriate shaping of the assembly comprising the two retaining grooves 13, 131, the two clamping grooves 3, 31 and the associated grooves 16, 161, the shape of the housing 1 is defined in the area of its two side edges 2, 21 to provide for attachment of the sensors.

9

Claims

1. A means f or attaching at least one sensor to an elongate housing comprising at least one longitudinally extending clamping groove provided on the housing outer surface, the clamping groove having a groove flank which narrows the groove width towards the groove opening, and a groove or surface extending coaxially to the axis of symmetry of the sensor in parallel with and adjacent to the clamping groove and supporting respectively within it, or on it, a screw associated with the sensor, by means of which screw at least one surface portion of the sensor may be pressed under the groove flank when the screw is tightened, in such a way that a frictional and formfitting connection is formed between the clamping groove and the sensor.

2. A means as claimed in Claim 1, wherein the at least one clamping groove is arranged in the region of a side edge of the housing.

3. A means according to either Claim 1 or Claim 2 wherein at least two clamping grooves are provided, the clamping grooves being arranged in adjacent pairs at at least one side edge of the housing, and wherein the point of intersection of the two axes of symmetry of the sensors attached to the or each pair of clamping grooves forms a right or acute angle.

4. A means as claimed in any preceding Claim wherein the or each clamping groove has a groove bottom and two groove flanks extending therefrom, the bevelled groove flank forming an acute angle of < 900 with the groove bottom.

5. A means as claimed in any preceding Claim wherein a transparent angular cover strip conformed to the overall cross-sectional shape of the housing is attached to the housing over the or each sensor and a signal line coming from the sensor.

6. A means as claimed in Claim 5 wherein the angular cover strip is attached to the housing through a snap connection by way of two retaining grooves extending in parallel with each other in the housing.

7. A means as claimed in either Claim 5 or Claim 6 wherein the angular cover strip has an outwardly extending projection on at least one longitudinal edge.

1

8. A means for attaching at least one sensor to an elongate housing substantially as hereinbefore described and illustrated in the accompanying drawings.

11 Amendments to the claims have been filed as follows CLAIMS 1. A means for attaching at least one sensor to an elongate housing comprising at least one longitudinally extending clamping groove provided on the housing outer surface, the clamping groove having a groove flank which narrows the groove width towards the groove opening, and a groove or surface extending coaxially to the axis of symmetry of the sensor in parallel with and adjacent to the clamping groove and supporting respectively within it, or on it, a screw associated with the sensor, by means of which screw one surface portion of the sensor may alone be pressed under the groove flank when the screw is tightened, in such a way that a frictional and formfitting connection is formed between the clamping groove and the sensor.

2. A means as claimed in Claim 1, wherein the at-least one clamping groove is arranged. in the region of a side edge of the housing.

12 4. A means as claimed in any preceding Claim wherein the or each clamping groove has a groove bottom and two groove flanks extending therefrom, the bevelled groove flank forming an acute angle of < 900 with the groove bottom.

# c 9 1 1.

0 t g. k c a 0 a h 4 a 0 6. A means as claimed in Claim 5 wherein the angular cover strip is attaced to the housing through a snap connection by way of two retaining grooves extending in parallel with each other in'he housing.