GB2259611A

GB2259611A - Cable and sensor attachment for a linear drive

Info

Publication number: GB2259611A
Application number: GB9217353A
Authority: GB
Inventors: Rudolf Moeller; Peter Mueller; Helmut Goettling; Gerhard Scharnowski
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1991-08-14
Filing date: 1992-08-14
Publication date: 1993-03-17
Anticipated expiration: 2012-08-14
Also published as: IT1255404B; ITMI921630A1; GB9217353D0; FR2680430A1; FR2680430B1; GB2259611B; DE4127204A1; ITMI921630A0

Abstract

The attachment comprises a body 6 defining a closed chamber for a sensor 24 and cables 25, and is attached to the linear drive housing 1 by at least one projection 5 with spreading jaws 6d, 6e which fit into a groove 3b. A threaded screw 12 cuts into the jaws to fix them in place. In an alternative embodiment, Figure 2, the housing 1 has a projection (3a) around which clamping jaws (6b, 6c) are secured by a screw. The attachment has a catch 18 and hinge 11 for access to the chamber. The magnetic field sensor 24 can be moved within the chamber in relation to magnet holder 26. Name plates 29 can be added to the attachment. <IMAGE>

Description

" ? r n 4 4 4 1 Sensor attachment assembly for a linear drive This

invention relates to sensor attachment assemblies for elongate housings of linear drives.

From a brochure of the company F.A. Mecman UScanning unit for 170 Series" it is known to cover sensors on a linear unit by means of a U-shaped sheet metal profile and to allow the connecting cable to sag freely. From another brochure, of the company Martonair "Magnetic piston system Type M/457 XX" it is known to guide the cable and the magnetic switches (magnetic field sensors) in a switching strip and likewise allows the cable to sag freely outside the switching strip.

In pneumatic linear drives, the position of the piston can be determined by scanning on the outsides of the cylinder. In the case of a pneumatic cylinder without a piston rod, a magnet system (permanent magnet) for contact-free scanning of the position of the piston by a magnetic field sensor (reed switch) is built into the piston. Another configuration provides for the arrangement of the permanent magnet on the force collector of a cylinder. The sensors or magnetic switches must therefore be attached at any desired point on the elongate housing and their position must be adjusted. The respective number of sensors and their position is determined by the particular case of operation. The cable therefore has to be guided and attached depending on its position.

The systems described above are disadvantageous in terms of lacking development of the attachment and of the protection of sensors and cables, and there is the risk of injury when manipulating such housings.

The present invention is directed at a sensor attachment assembly for an elongate housing in for example, a linear drive, on the outer surface of which 2 housing at least one projection or groove is formed. According to the invention, where the housing has a projection, the assembly comprises a body with clamping jaws on the base thereof adapted to encompass said at least one projection with initial tension, the body defining a protected region for a sensor and a space for cable to run. Where the housing has a groove, the assembly comprises at least one projection with spreading jaws adapted to engage in said at least one groove with initial tension, the body defining a protected region for a sensor and a space for cable to run.

Assemblies of the invention can be manufactured economically and are simple to assemble, and provide a useful means of stowing cables. The sensor or sensors therein can be easily and reliably adjusted, while being effectively protected.

According to further features of the invention, particular provision is made for the assembly to be used with a housing in which an attachment groove has a dovetail profile. The projection on the body also has a dovetail profile with a film hinge in the base thereof, which hinge enables the profile to distort as a said projection is fitted to the groove. The projection is secured in the groove by a spreading element in the form of a threaded screw which cuts into the juxtaposed faces of the jaws. This enables the body to be mounted on the housing and then moved into any longitudinal desired position prior to securement.

In preferred assemblies of the invention, the body defines a chamber with a closure member hingedly attached thereto. It may have an additional hinge parallel to and at a corner adjacent the closure member hinge. The body may also have a snap-in connection for the closure member, which connection comprises an 3 is insertion bar and an undercut catch space for receiving same. Such a body may be produced as a plastics profile in an extrusion process. The elastic hinges may therefore be formed during production. This obviates the need for special attachment means, but nevertheless results in a readily accessible and completely closable chamber.

The sensor itself can be clamped between an angle plate located within the body and the body itself, typically by means of a threaded screw. The sensor is released by slightly loosening the screw, and can be displaced in the longitudinal direction and thus aligned accurately, i.e. be positioned within the length, as desired. Provision can also be made for the ordered positioning of cable strands in the body running parallel in the body beneath the angle plate.

Resilient cable clips can be fitted for this purpose.

Embodiments of the invention will now be described by way of example and with reference to the accompanying schematic drawings wherein:

Figure 1 is a perspective part sectional view of a first embodiment of the invention on a housing of a piston rod-less cylinder in the operating state; Figure 2 is a view similar to that of Figure 1 of a second embodiment of the invention; and Figures 3 to 5 show perspective views similar to Figure 1 illustrating the mounting of the assembly on a housing.

The sensor attachment is equipped with a connection for an elongate linear drive housing 1, on the outer surface 2 of which attachment projections 3a or attachment grooves 3b run. on said outer surface 2, 4 is the attachment projections 3a are raised or the attachment grooves 3b are recessed. Either clamping jaws 6b and 6c which encompass the attachment projections 3a (Figure 2) or spreading jaws 6d and 6e which engage in the attachment grooves 3b (Figure 1) are provided on a base-6a of a housing 6.

A projection 5 of hollow interior, which is continuous or divided into individual sections and lines the attachment groove 3b on its groove walls 4, is present on the housing 6. Said hollow projection 5 forms part of the closable or hinged housing 6, which can thus be displaced back and forth and clamped securely on the linear drive housing 1 due to the hollow projection 5.

In order that the clamping jaws 6b, 6c can be placed under initial tension, to this end a cavity 7 is formed in the hollow projection 5, and one or more detachable spreading elements 8 are inserted into said cavity, which elements upon insertion press the hollow projection 5 against the groove walls 4 from the inside by means of the spreading jaws 6d, 6e. In the embodiment illustrated, the attachment groove 3b is provided with a dovetail profile 9. The cavity 7 in this case is provided centrally opposite the base 10 of the groove with a film hinge 11, so that when the housing 6 is opened the thus far empty housing can first of all be introduced somewhat folded up with the hollow projection 5 from the front, i.e. at right-angles to the outer surface 2, and then the spreading element 8 is inserted for clamping. The latter consists of a threaded screw 12 which cuts into the material of the projection 5, so that here too the factor of simple design and economy remains guaranteed.

The housing 6 is made of one piece, so that the projection 5 forms part of this one-piece housing 6. It is is preferably made of polyamide with fillers, such as glass fibres and the like. In addition to the film hinge 11 which runs on the base 10 of the groove, at least one additional film hinge 11 is provided in a first corner region 13 of the housing cross-section 14, and one in a second corner region 15. Furthermore, a snap-in connection 18 for a closable flap 19 is located on the housing 6, which connection consists of an insertion bar 16 and an undercut catch space 17 for receiving it. The first corner region 13 is specially formed in that the film hinge 11 therein in the assembled state is provided with a thickened section 21 and supporting wall section 22 which adjoins a film wall 11a and can be supported on one another.

Furthermore, an angle plate 23 located within the housing 6 formed is provided by means of the threaded screw 12, and a sensor 24 (magnetic field sensor) clamped between the housing wall 14a and the angle plate 23 is attached by means of said angle plate 23. By loosening the threaded screw 12, therefore, not only the entire housing 6 can be positioned within the length of the linear drive housing 1, but also the sensor 24, which can be set, corresponding to the switching position of the permanent magnet on the piston or on a force collector 30.

Advantageously, a plurality of cable strands 25 may be inserted running parallel in the housing 6 beneath the angle plate 23. In the embodiment of Figure 1, moulded-on cable clips 19a are integrated in the wall of the flap 19.

As Figures 3 to 5 show, the manipulation of the sensor attachment with cable duct takes place in the steps described below:

In the stage illustrated in Figure 3 the hollow projection 5 is introduced into the attachment groove, 6 folding up the housing 6 at the film hinge 11, until the hollow projection 5 is received in the attachment groove.

According to Figure 4, once the flap 19 has been opened access into the interior of the housing 6 can be had, and the angle plate 23 can be inserted together with the threaded screw 12 and be tightened by means of the screwdriver 27, so that firstly the housing 6 is positioned and secondly the sensor 24 as well.

Once this operation has ended and additional cable strands 25 for additional sensors 24 have been inserted, the closable flap 19 is pushed in via the snap-in connection 18, as shown in Figure 5, so that the housing 6 is then finally closed and no sagging cable strands 25 or exposed sensors 24 are present. On the upper side of the housing 6, furthermore, there may be formed a longitudinal recess 28 (Figure 1) into which nameplates 29 for marking the individual cable connections or the like can be inserted, in which case such a nameplate 29 can likewise be placed at the level of the sensor 24. Above said recess there is a magnet holder 26.

At one end of the housing 6 there is a closing cover (not shown). Such a closing cover is equipped with a socket for electrical connection if required. The cable strands 25 of the sensors 24 are then connected to said sockets. A plug to which the feed lines from the control means are connected in turn engages in such a socket.

An apparatus unit equipped with this described sensor attachment or cable duct can thus be installed or dismantled completely cabled. In this case only the aforementioned plug has to be connected or disconnected.

21 I-

Claims

1. A sensor attachment assembly for a linear drive housing on the outer surface of which at least one projection is formed, the assembly comprising a body with clamping jaws on the base thereof adapted to encompass said at least one projection with initial tension, the body defining a protected region for a sensor and a space for cable to run.

2. An assembly according to Claim 1 including means for closing the jaws on said at least one projection.

3. A sensor attachment assembly for a linear drive housing on the outer surface of which at least one groove is formed, the assembly comprising at least one projection with spreading jaws adapted to engage in said at least one groove with initial tension, the body defining a protected region for a sensor and a space for cable to run.

4. An assembly according to Claim 3 including means for spreading the jaws within said at least one groove.

5. An assembly according to Claim 4 wherein the spreading means comprises an element movable between the jaws.

6. An assembly according to Claim 5 wherein the spreading element has screw threads for cutting into the juxtaposed faces of the jaws.

7. An assembly according to any of Claims 3 to 6 wherein said at least one projection has a dovetail profile with a film hinge in the base thereof, which hinge enables the profile to distort as a said projection is fitted to a matching groove.

is

8. An assembly according to any preceding Claim wherein the body defines a chamber with a closure member hingedly attached thereto.

9. An assembly according to Claim 8 wherein the body has an additional hinge parallel to and at a corner adjacent the closure member hinge.

10. An assembly according to Claim 9 wherein the body is formed with a thickened section and a wall section on opposite sides of the additional hinge to limit the pivotal movement of the additional hinge in one sense.

11. An assembly according to any of Claims 8 to 10 wherein the body includes a snap-in connection for the closure member, which connection comprises an insertion bar and an undercut catch space for receiving same.

12. An assembly according to any preceding claim including an angle plate located within the body which holds a sensor against a wall of the body.

13. An assembly according to Claim 12 wherein a plurality of cable strands are disposed in the body beneath the angle plate.

14. An assembly according to Claim 13 wherein the body includes resilient cable clips for supporting the cable strands.

15. A sensor attachment assembly for a linear drive substantially as described herein with reference to the accompany drawings.

16. A linear drive including a sensor attachment assembly according to any preceding Claim.