DE20312472U1 - Hydraulic cylinder linear drive sensor mount is clamped by spring loop with selection of fine adjustment or clamped position using clamp pin knob - Google Patents

Abstract

A hydraulic cylinder (3) linear drive sensor mount (1) has a sensor carrier (23) moving in a slot (7) and clamped by a spring loop (27) held by a clamp pin knob (57) allowing fine adjustment of final fixed positions with use of either the upper spring arms or both upper and lower spring arms.

Description

G 22567 - leah July 25, 2003

FESTO AG & Co, 73734 Esslingen Mounting device for a sensor

The invention relates to a fastening device for the detachable clamping fastening of a sensor in a fastening groove, which has a groove neck and an anchoring section adjoining it via two longitudinal shoulders in the groove depth direction, with a sensor carrier which can be inserted into the fastening groove together with a spring-elastic clamping part fixed to it in such a way that the shoulders of two clamping sections of the clamping part lying opposite one another in the transverse direction of the groove are gripped under, and with an actuating member which can be inserted between the two clamping sections in order to press the clamping sections apart and to clamp them to the inner surface of the groove.

The present invention relates to measures for fastening sensors, particularly in connection with position detection on fluid-operated drives. This involves the detection of certain positions of moving components, for example the piston of a pneumatic cylinder. DE 199 53 186 A1 discloses a fastening device of the type mentioned at the beginning, in which a spring-loaded

theelastic clamping part is arranged, which has two spring tongues that protrude into the fastening groove, between which an actuating element designed as a screw can be inserted in order to spread them apart and clamp them to the inner surface of the groove. One of the disadvantages here is that the clamping force generated is at the discretion of the fitter tightening the actuating element, so that damage cannot be ruled out.

DE 94 14 869 Ul discloses a linear drive whose housing has a fastening groove on the outside in which a sensor can be fixed using a suitable fastening device. The sensor responds to an actuating element, in particular a permanent magnet, which is provided on a piston arranged so as to be displaceable in the housing of the linear drive. The fastening device has an elongated sensor carrier, on one end of which a rotary member is provided which, when inserted into the fastening groove, can be pivoted under the two shoulders of the fastening groove and which is then clamped to the shoulders by a fastening screw which can be screwed against the base of the groove.

A similar fastening device is described in DE 2 98 811 Ul, in which the rotary member is clamped to the groove flanks oriented in the transverse direction of the groove.

It is the object of the present invention to provide an easy-to-use and reliably functioning fastening device for sensors.

To solve this problem, it is provided that the two clamping sections are designed as spring-elastic clamping brackets with their openings facing each other, the bracket legs of which are at the same height in pairs, and that the actuating member is designed as an actuating plunger which can be positioned either in a pre-fixing position which only dips between the outer bracket legs closer to the groove neck or in a final fixing position which dips between both the outer and the inner bracket legs which lie deeper in the fastening groove, whereby it presses apart either only the outer or both the outer and the inner bracket legs.

The actuating element can normally be positioned in a release position in which it does not or only minimally impact the bracket legs and in which it does not protrude between the bracket legs. In addition, it is possible to position the actuating plunger in a pre-fixing position and a final fixing position in which the two clamping brackets are pressed against the inner surface of the groove with a different, defined force, whereby

The pre-fixing position allows the sensor carrier to be adjusted in the longitudinal direction of the fastening groove in order to carry out a fine adjustment, and the final desired position is fixed practically immovably in the final fixing position. Since the individual fastening states can be specified in a defined manner, handling is very simple without the risk of overstressing a component.

Advantageous further developments of the invention emerge from the subclaims.

Preferably, the actuating plunger is positioned in the release position so that it does not dip between the bracket legs and, in particular, is located completely outside the clamping part. Nevertheless, it is advantageous if the actuating plunger is also held directly or indirectly on the sensor carrier in the release position and does not represent a separate, loose component.

The outer and/or inner bracket legs of the clamping brackets are expediently connected to one another via an eyelet section, which can be elastically expanded by the immersed actuating plunger. The eyelet section can be partially formed by the end sections of the bracket legs. If at least one such eyelet section is present, the

Clamping bracket is a coherent structural unit, whereby in the case of two eyelet sections the shape of a ring body can be achieved.

Preferably, the clamping part is made of spring steel.

A guide tube fixed to the sensor carrier can reach through between the associated bracket legs of the two clamping brackets, into which the actuating plunger can be inserted more or less far for the desired positioning. To ensure that the bracket legs are acted upon, the guide tube is slotted on the circumference at the height of the bracket legs so that the bracket legs protrude radially into the interior of the guide tube with an actuation section and can be acted upon there by the actuating plunger.

A cover plate can be arranged on the outer end area of the guide tube, which covers the clamping part and which, when the fastening device is installed, is expediently located inside the groove neck of the fastening groove and spans the groove neck over at least approximately the entire width. In this way, the stability of the arrangement can be increased and the clamping part can also be protected from excessive contamination.

The actuating plunger is expediently held captive in relation to the sensor carrier. In this connection, a locking pin can be arranged coaxially in the guide tube, which is telescopically engaged over by the actuating plunger, which is hollow over at least part of its length, with securing means being provided on the locking pin and the actuating plunger, which engage behind one another transversely to the direction of displacement and by which the extension path of the actuating plunger is limited by specifying the release position.

At the outer end of the actuating plunger there is conveniently an actuating head that allows the actuating plunger to be moved manually. In the final fixing position of the actuating plunger, this assumes a position that is as close as possible to the clamping part. Since the actuating head is usually located in the immediate vicinity of the outer surface of the body with the fastening groove, it is recommended to attach a bevelled surface to the circumference of the actuating head that allows easy gripping behind it for the purpose of pulling out the actuating plunger.

The invention is explained in more detail below with reference to the accompanying drawings, in which:

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Figure 1 shows a schematic representation of a section of a fluid-operated linear drive which is equipped with a sensor for position detection by means of a preferred design of the fastening device,

Figure 2 shows the arrangement from Figure 1 in longitudinal section in a schematic representation, with the actuating plunger in the pre-fixing position,

Figure 3 shows a cross-section through the arrangement of Figure 2 according to section line III - III in a partial representation and with the actuating plunger in the pre-fixing position,

Figure 4 shows the arrangement from Figure 3 when the actuating plunger is in the release position,

Figure 5 shows the arrangement from Figure 3, when the actuating plunger is in the final fixing position,

Figure 6 is a plan view of the fastening device looking in the direction of arrow VI in Figure 4, showing only a cover plate and the clamping part underneath it, and

Figure 7 is a perspective detailed view of a preferred embodiment of the clamping part.

The drawing shows a detail of a fluid power device, here in the form of a linear drive 1 that can be actuated by fluid power and in particular pneumatically.

The linear drive 1 has a housing 2, which is only partially shown in cross-section in Figures 3 to 5. An elongated chamber 3 is formed inside the housing 2, in which a piston is located that can be moved by fluid force. The piston 4 is equipped with an actuating element 5 for the useless actuation of a sensor 6, which is only indicated by dashed lines. The actuating element is in particular a permanent magnet.

On its outside, the housing 2 is provided with at least one fastening groove 7. This has a linear course and is open along the side, towards the outer surface 8 of the housing 2. The aforementioned sensor 6 can be fastened in the fastening groove 7 by means of a detachable clamp connection with the help of the fastening device 12 according to the invention.

In principle, the fastening device 12 can be used in conjunction with fastening grooves of any cross-sectional shape. However, its use proves particularly advantageous.

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connection in conjunction with a fastening groove 7 designed as a T-slot, the embodiment being explained using such a design.

The fastening groove 7 is T-shaped in cross-section and has a groove neck 13 that is open towards the outer surface 8, to which a wider, preferably rectangular anchoring section 15 is connected inwards in the groove depth direction 14 marked by a double arrow via two longitudinal shoulders 16 facing the groove base 18. The shoulders 16 are defined by the underside of two rib-like projections 17 that define the groove neck 13. The shoulders 16 end in the transition area to the groove neck 13 with an edge 19.

The fastening device 12 contains a sensor carrier 23 which is elongated in the embodiment and which can be inserted into the fastening groove 7 from the front sides or through the groove neck 13. At one end, the sensor carrier is stepped and has a base plate 24 which rests with its underside on the groove base 18 and whose height measured in the groove depth direction 14 is less than that of the anchoring section 15.

When the sensor carrier 23 is inserted into the fastening groove 7, the sensor 6 is also located within the

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fastening groove 7, wherein it preferably lies completely within the anchoring section 15, as close as possible to the groove base 18.

In the exemplary embodiment, the sensor 6 is housed in a support section 25 of the sensor carrier 23 that adjoins the base plate 24. The electrical connection of the sensor 6 can be made via an outgoing cable 26. However, the sensor 6 could also be designed using transponder or radio technology, for example, so that the sensor signals can be transmitted wirelessly to a receiver.

A preferred design of the fastening device 12 will be discussed in more detail below.

The fastening device 12 has a spring-elastic clamping part 27, preferably made of spring steel or a spring-elastic plastic material, which is shown separately in Figure 7. This clamping part 27 is fixed to the sensor carrier 23 so that it forms a jointly manageable structural unit. In the exemplary embodiment, it sits on the base plate 24. When the sensor carrier 23 is inserted into the fastening groove 7, the clamping part 27 also comes to lie within the fastening groove 7, at least partially within the anchoring section 15.

The clamping part 27 has two bracket-like clamping sections, for example at least essentially U-shaped, which are referred to as clamping brackets 28 due to their shape. These clamping brackets 28 are arranged next to one another in the groove transverse direction 32 marked by a double arrow, i.e. at right angles to the groove depth direction 14, wherein they are at the same height with respect to the groove depth direction 14 and wherein their openings face one another. When inserted into the fastening groove 7, to which the present description refers unless otherwise stated, each clamping bracket 28 has an inner bracket leg 33a, 33b located closer to the groove base 18 and an outer bracket leg 34a, 34b located further away from the groove base 18. The bracket legs 33a, 33b, or 34a, 34b of a respective clamping bracket 28 are connected to one another, in particular in one piece, via a connecting section 35 facing the adjacent groove flank. The bracket legs of a respective inner and outer bracket leg pair are at the same height.

In principle, it would be possible to design the clamping brackets 28 as separate parts. However, it has proven to be useful if both the inner (33a, 33b) and the outer (34a, 34b) bracket legs are connected to one another via an outer or inner eyelet section 37.

In this way, the clamping part 27 according to Figure 7 can have the shape of a ring body.

To simplify production, the ring body can also be interrupted at one point on the circumference, for example by a slot. To create the interruption, for example, only the outer or only the inner stirrup legs could be connected to one another via an eyelet section, while the other stirrup legs end freely, leaving a gap between them and without being connected to one another.

The clamping part 27 is arranged on the sensor carrier 23 in such a way that its longitudinal axis 38, which passes through the two connecting sections 35, runs in the transverse direction 32 of the groove. For the eyelet section 36, 37, an elongated design with a preferably elongated hole-shaped eyelet opening 42 is recommended, the longitudinal axis of which runs at right angles to the longitudinal axis 38 of the clamping part 27 and coincides with the longitudinal direction of the groove, with the bracket legs 33a, 33b and 34a, 34b engaging longitudinally on the respective eyelet section 36, 37. In this way, the longitudinal sections of the eyelet sections 36, 37 are each formed at least partially by the associated end section of the bracket leg in question.

The clamping part 27 is fitted with the eyelet openings 42 onto a guide tube 43 which passes through both eyelet sections 36, 37. The guide tube 43 is attached at one end to the sensor carrier 23 - in this case to the base plate 24 - from where it extends in the groove depth direction 14 to the groove neck 13. In the exemplary embodiment, the guide tube 43 is inserted from above into an opening 44 in the base plate 24 and locked there.

In the exemplary embodiment, a cover plate 45 covering the clamping part is arranged on the opposite outer end region of the guide tube 43. In the exemplary embodiment, this is formed in one piece with the guide tube 43 and can also be omitted if required. In particular, it is arranged and designed such that it comes to rest in the groove neck 13 of the fastening groove 7 and spans the groove neck 13 over at least approximately its entire width. This results in a certain protection of the clamping part 27 arranged between the cover plate 45 and the base plate 24 against damage and contamination.

At the level of the pairs of inner or outer bracket legs 33a, 33b or 34a, 34b, the guide tube 43 is slotted along part of its circumference. At the level of the two pairs of bracket legs, the guide tube 43 has two diametrically opposed circumferential slots 46 through which

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through which the respectively associated bracket leg with a loading section 47 projects radially inwards into the interior of the guide tube 43.

This is achieved in the embodiment in that the width of the eyelet opening 42 is selected to be smaller than the inner diameter of the guide tube 43, so that the eyelet section 36, 37 in question engages laterally in the guide tube 43 with the length sections formed by the end sections of the bracket legs.

This engagement results in a positive connection between the individual bracket legs 33a, 33b or 34a, 34b and the guide tube 43 in the longitudinal direction of the guide tube 43, so that the bracket legs are fixed at their respective end sections in the groove depth direction.

The clamping brackets 28 are designed in such a way that they grip the two shoulders 16 of the fastening groove 7 from the side of the anchoring section 15. At the same time, the clamping brackets 28 are supported on the base plate 24 of the sensor carrier 23 either directly or through the positive connection with the guide tube 43 from above.

To activate the fastening device 12, an actuating member designed as an actuating plunger 48 is provided.

Starting from a release position shown in Figure 4, in which it does not dip between the opposing bracket legs, the actuating plunger 48 can be inserted between the clamping brackets 28 in such a way that it either only reaches through the outer eyelet section 37 or through both the outer and the inner eyelet sections 37, 36. In the first case, the pre-fixing position illustrated in Figure 3 is present, and in the second case, the final fixing position shown in Figure 5 is present.

The outer diameter of the actuating plunger 48 is larger than the distance between two opposing loading sections 47. This has the consequence that the inserted actuating plunger 48 exerts a compressive force either only on the loading sections 47 of the outer bracket legs 34a, 34b (pre-fixing position) or on the loading sections of both the inner and the outer bracket legs 33a, 33b or 34a, 34b (final fixing position), which compressive force coincides with the groove transverse direction 32 and is directed towards the groove flanks of the fastening groove 7.

In both the pre-fixing position and the final fixing position, the two clamping brackets are pushed apart and clamped to the inner surface of the groove. It is particularly intended that the outer bracket legs 34a, 34b are inclined from below.

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pressed against the two shoulders 16 and pre-tensioned against them.

However, depending on the position of the actuating plunger 48, different intensities of the pre-tension arise. Since in the pre-fixing tension only the outer bracket legs 34a, 34b are spread apart, the clamping force caused is lower than in the final fixing position, in which the actuating plunger 48 also spreads apart the inner bracket legs 33a, 33b.

In this context, the design is such that the sensor carrier 23 equipped with a sensor 6 is already fixed in the fastening groove 7 in the pre-fixing position in such a way that it can no longer move automatically even when aligned vertically, but that the clamping force is reduced to a level that still allows the sensor carrier 23 to be moved in the longitudinal direction of the fastening device 7 with a certain amount of force.

Once the desired position of the sensor carrier 23 or of the sensor 6 carried by it has been found, the actuating plunger 48 is moved into the final fixing position, whereby the now increased clamping force ensures that the sensor carrier 23 can no longer be adjusted in the longitudinal direction of the fastening groove 7, even with greater force.

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Due to the elongated design of the eyelet sections 36, 37, a spring elasticity also results in this area, which allows an elastic widening of the eyelet opening 42 when the actuating plunger 48 with the larger diameter is inserted, with the resulting displacement of the loading sections 47 radially outwards with respect to the guide tube 43.

Conveniently, the outer diameter of the actuating plunger 48 corresponds to the inner diameter of the guide tube 43 in such a way that the displacement movement 52 required to set the desired position, indicated by a double arrow, is possible.

In the embodiment, the actuating plunger 48 has the same outer diameter over its entire effective length, and the distance between the opposing bracket legs 33a, 33b and 34a, 34b is the same when not actuated. When the actuating plunger 48 is inserted, the outer and then the inner bracket legs are pushed apart by a comparable amount. However, it would also be conceivable in principle to design the actuating plunger 48 with a non-constant cross-section and, for example, with a conical shape. The distances between the opposing bracket legs 33a, 33b and 34a, 34b could also be

The clamping force can vary depending on the clamping arm. This allows the generation process and the actual level of clamping forces that can be achieved to be influenced.

The actuating plunger 48 could be a separate component that is not coupled to the sensor carrier 23 in the release position. However, it is more advantageous to implement a design comparable to the embodiment in which the actuating plunger 48 is constantly held on the sensor carrier 23 in a way that prevents it from being lost.

This can be done in particular by arranging a locking pin 53 coaxially in the guide tube 43, which cannot be removed from the guide tube 43 and which is coaxially engaged over by the actuating plunger 48 in a telescopic manner, wherein the actuating plunger 48 is hollow over at least part of its length so that the locking pin 53 can move coaxially into it.

As can be clearly seen from Figure 4, suitable securing means 54 are provided at the outer end of the locking pin 53 and at the inner end of the actuating plunger 48, which engage behind one another transversely to the direction of displacement 52, so that the withdrawal path of the actuating plunger 48 is limited by specifying the release position. The guide tube 43 is located here

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completely outside the clamping part 27 and also the fastening groove 7.

If the actuating plunger 48 is pressed into the clamping part, it slides coaxially over the locking pin 53, which in the process plunges into the cavity 55 formed in the actuating plunger 48.

In order to ensure that the actuating plunger 48 can be completely pulled out of the clamping part 27 in the release position despite the compact dimensions, the locking pin 53 is arranged in the guide tube 43 so that it can move axially to some extent. Its outer end associated with the securing means 54 can therefore protrude further outwards beyond the clamping part 27 in the release position than, for example, in the final fixing position.

In this context, the locking pin 53 is provided at its inner end with at least one locking projection 56 which, in the embodiment, projects radially outwards in the manner of a ring collar and which is displaceably supported on the inner surface of the guide tube 43. The locking projection 56 is located below the clamping part 27, and in the embodiment it is located in the length section of the guide tube 43 which passes through the base plate 24. The locking projection 56 secures the locking pin 53 to a full

constant pulling out of the guide tube 43 is prevented, since the securing projection 56 engages behind the loading sections 47 of the inner bracket legs 33a, 33b on the side facing the groove base 18 and cannot pass through them. At the same time, however, the securing projection 56 has the possibility of moving within the aforementioned length section of the guide tube 43 in order to thus ensure the aforementioned displaceability of the securing pin 53.

For convenient, effort-saving activation of the actuating plunger 48, an actuating head 57 with a larger cross-section is expediently arranged at its outer end. This is firmly connected to the actuating plunger 48 and in particular is designed as a single piece.

Since the actuating head 57, which is designed, for example, in the form of a plate, comes to lie in the immediate vicinity of the groove neck 13 in the final fixing position, it is provided on the outer circumference, towards the clamping part, with a bevel 58 which runs all the way around, which allows easy gripping with the fingers in order to be able to apply the pulling force required to pull out the actuating plunger 48.

While the clamping brackets 28 in the embodiment are angled several times to maintain their shape, in practice they could also be realized rounded.

The clamping part 27 could easily have a shape that allows insertion through the groove neck 13 into the fastening groove 7 in the release position of the actuating plunger 48. In the exemplary embodiment, it is possible to rotate the clamping part 27, before insertion into the fastening groove 7, relative to the sensor carrier 23 into a position in which the longitudinal axis 38 coincides with the longitudinal direction of the fastening groove 7, so that the width dimensions are smaller than those of the groove neck 13. After insertion, the clamping part 27 is then rotated again into the desired transverse orientation.

Claims (17)

1. Fastening device for the detachable clamping fastening of a sensor in a fastening groove ( 7 ) which has a groove neck ( 13 ) and an anchoring section ( 15 ) which adjoins it via two longitudinal shoulders ( 16 ) in the direction of the groove depth, with a sensor carrier ( 23 ) which, together with a spring-elastic clamping part ( 27 ) fixed to it, can be inserted into the fastening groove ( 7 ) in such a way that the shoulders ( 16 ) are gripped under by two clamping sections of the clamping part ( 27 ) which are opposite one another in the transverse direction of the groove, and with an actuating member which can be inserted between the two clamping sections in order to press the clamping sections apart and to clamp them to the inner surface of the groove, characterized in that the two clamping sections are designed as spring-elastic clamping brackets ( 28 ) with their openings facing one another, the bracket legs ( 33 a, 33 b; 34 a, 34 b) lie in pairs at the same height, and that the actuating member is designed as an actuating plunger ( 48 ) which can be positioned optionally in a pre-fixing position which only penetrates between the outer bracket legs ( 34 a, 34 b) which lie closer to the groove neck ( 13 ) or in a final fixing position which penetrates between both the outer ( 34 a, 34 b) and the inner bracket legs ( 33 a, 33 b) which lie deeper in the fastening groove ( 7 ), wherein it presses apart either only the outer ( 34 a, 34 b) or both the outer ( 34 a, 34 b) and the inner bracket legs ( 33 a, 33 b). 2. Fastening device according to claim 1, characterized in that the actuating plunger ( 48 ) can be positioned in a release position which does not penetrate between the bracket legs ( 33 a, 33 b; 34 a, 34 b). 3. Fastening device according to claim 2, characterized in that the outer and/or inner bracket legs ( 34 a, 34 b; 33 a, 33 b) are connected to one another via an eyelet section ( 36 , 37 ) which can be elastically expanded by the immersing actuating tappet ( 48 ). 4. Fastening device according to claim 3, characterized in that the eyelet opening ( 42 ) is designed in the shape of an elongated hole, wherein the bracket legs ( 33 a, 33 b; 34 a, 34 b) are assigned to the longitudinal eyelet sections ( 36 , 37 ). 5. Fastening device according to claim 3 or 4, characterized in that the clamping part ( 27 ) is an annular body composed of two clamping brackets ( 28 ) and two eyelet sections ( 36 , 37 ). 6. Fastening device according to one of claims 1 to 5, characterized in that the clamping part ( 27 ) consists of spring steel. 7. Fastening device according to one of claims 1 to 6, characterized in that a guide tube ( 43 ) fixed to the sensor carrier ( 23 ) extends between the mutually associated bracket legs ( 33 a, 33 b; 34 a, 34 b), into which the actuating plunger ( 48 ) can be inserted to a greater or lesser extent and which is slotted at the level of the bracket legs such that they each protrude a little way into the interior of the guide tube ( 43 ) with an actuating section ( 47 ) which can be pressed outwards by the actuating plunger ( 48 ). 8. Fastening device according to claim 7, characterized in that the guide tube ( 43 ) is locked to the sensor carrier ( 23 ). 9. Fastening device according to claim 7 or 8, characterized in that a cover plate ( 45 ) covering the clamping part ( 27 ) is arranged at the outer end region of the guide tube ( 43 ). 10. Fastening device according to claim 9, characterized in that the cover plate ( 45 ) in the installed state of the fastening device comes to lie in the groove neck ( 13 ) of the fastening groove ( 7 ) and spans this at least approximately over the entire width. 11. Fastening device according to one of claims 7 to 10, characterized in that a locking pin ( 53 ) is arranged coaxially in the guide tube ( 43 ), which is telescopically engaged over by the actuating plunger ( 48 ) which is hollow over at least part of its length, wherein securing means ( 54 ) are provided on the guide pin ( 53 ) and on the actuating plunger ( 48 ) which engage behind one another transversely to the direction of displacement ( 52 ), by means of which the withdrawal path of the actuating plunger ( 48 ) is limited by specifying a release position which does not engage the bracket legs of the clamping part ( 27 ). 12. Fastening device according to claim 11, characterized in that the actuating plunger ( 48 ) is arranged outside the clamping part ( 27 ) in the release position. 13. Fastening device according to claim 11 or 12, characterized in that the locking pin ( 53 ) is prevented from being removed from the guide tube ( 43 ) by at least one locking projection ( 56 ) provided on it engaging behind the loading sections ( 47 ) of the inner bracket legs ( 33a , 33b ; 34a , 34b ) projecting into the guide tube (43) on the side facing the groove base ( 18 ). 14. Fastening device according to claim 13, characterized in that the locking pin ( 53 ) is displaceable relative to the guide tube ( 43 ) between an outer position which protrudes further from the guide tube (43), which is defined by the interaction of the at least one locking projection ( 56 ) with the loading sections ( 47 ) of the inner bracket legs ( 33a , 33b ), and an inner position arranged with a larger part of its length in the guide tube ( 43 ). 15. Fastening device according to one of claims 1 to 14, characterized in that an actuating head ( 57 ) enabling manual displacement of the actuating plunger ( 48 ) is arranged at the outer end of the actuating plunger ( 48 ). 16. Fastening device according to claim 15, characterized in that the actuating head ( 57 ) is bevelled all around on the circumference, towards the clamping part ( 27 ), in order to enable manual gripping from behind to facilitate pulling out of the actuating plunger ( 48 ). 17. Fastening device according to one of claims 1 to 16, characterized in that the clamping part ( 27 ) is arranged on a base plate ( 24 ) of the sensor carrier ( 23 ), which in the fixing positions is pressed against the groove base ( 18 ) of the fastening groove ( 7 ) by the clamping part ( 27 ) supported against the shoulders.