Sensor mounting device with a mounting strip and a mounting bracket

Abstract

Holding device (30) with at least one sensor (31) and a housing (12) for use in a linear motion device (10), wherein the housing (12) extends in a longitudinal direction (11) with a constant outer cross-sectional shape, wherein the holding device (30) has a separate retaining strip (50) with at least one undercut groove (51), wherein the retaining strip (50) extends in the longitudinal direction (11) with a constant cross-sectional shape, wherein the at least one sensor (31) is received in a respective associated undercut groove (51), characterized in that the holding device (30) has at least one separate retaining bracket (70), wherein the retaining bracket (70) has a base (71) extending transversely to the longitudinal direction (11), wherein the base is screwed to a first clamping screw (32) whose end face (33) rests against the retaining strip (50), wherein the at least one retaining bracket (70) has two legs (72) exhibitswhich extend perpendicularly from the base (71) so that they encompass the housing (12), wherein at least one leg (72) is screwed to a second clamping screw (34) whose end face (35) rests against the outside of the housing (12) so that the housing (12) can be clamped between the two legs (72), wherein the base (71) has a recess (74) open towards the housing (12) in which the retaining strip (50) is received.

Description

[0001] The invention relates to a holding device according to the preamble of claim 1.

[0002] On the website accessible on June 11, 2014, at http: / / www.festo.com / cms / de-chch / 21479.htm, a holding device for attaching a sensor to the housing of a linear motion device is disclosed under the “Accessories” section. The linear motion device is an electric cylinder with a housing that extends in a longitudinal direction with a constant external cross-sectional shape. The holding device comprises a holding strip, referred to as a “sensor strip.” The holding strip has an undercut groove and extends in a longitudinal direction with a constant cross-sectional shape. Sensors, such as inductive proximity switches or reed contacts, can be attached to the undercut groove, and their position can be continuously adjusted in the longitudinal direction. The holding strip is adhesively bonded to the housing of the linear motion device.This adhesive bond can be erased if the linear motion device comes into contact with liquid.

[0003] The object of the invention is to provide a holding device that does not come loose when it comes into contact with liquids. Furthermore, the holding bar should be able to be attached to the housing of the linear motion device without play, even if the dimensions of the housing are subject to manufacturing tolerances.

[0004] According to the independent claim, it is proposed that the holding device has at least one separate holding bracket, wherein the holding bracket has a base which extends transversely to the longitudinal direction, wherein the base is screwed to a first clamping screw, the end face of which bears against the holding strip, wherein the at least one holding bracket has two legs which project perpendicularly from the base so that they engage around the housing, wherein at least one leg is screwed to a second clamping screw, the end face of which bears against the outside of the housing so that the housing can be clamped between the two legs. The holding bracket is clamped to the housing with the second clamping screws. The holding strip is clamped to the housing with the first clamping screw, wherein the corresponding clamping force is supported on the housing via the holding bracket and the at least one second clamping screw.The axis of rotation of the first clamping screw is preferably aligned transversely to the base. The axis of rotation of the second clamping screw is preferably aligned transversely to the associated leg. The clamping forces of the first and second clamping screws are preferably selected to be large enough to cause plastic deformation of the retaining strip and the housing, respectively. This results in a positive engagement that can transmit high forces. The first and / or the second clamping screw are preferably secured against loosening, most preferably by means of an adhesive. The retaining strip and / or the at least one retaining bracket are preferably made of aluminum. The retaining strip is preferably produced using an extrusion process. The two legs preferably each have a free end that points away from the base. However, it is also conceivable for the retaining bracket to surround the housing in a ring-like manner, so that the legs are connected to one another at both ends.The second clamping screw is preferably arranged at a free end of the associated leg.

[0005] Advantageous further developments and improvements of the invention are specified in the dependent claims.

[0006] It is preferred that two or more identical retaining brackets be provided, each associated with the same retaining strip. This ensures that the retaining strip is held particularly firmly to the housing. A separate retaining bracket is preferably assigned to each end of the retaining strip, which is most preferably arranged at a short distance from the associated end of the retaining strip.

[0007] It is preferred that the first and / or second clamping screw is each formed by a threaded pin having a conical end face, wherein the threaded pin is screwed into an associated internal thread on the retaining bracket. The threaded pins can be arranged completely countersunk in the retaining bracket with respect to the outer surface thereof. The conical end face of the threaded pin digs particularly easily into the housing or retaining strip, resulting in a good form fit. Threaded pins are particularly cost-effective because they are standard parts. A threaded pin according to DIN 914 or DIN 553 is preferably used.

[0008] It is preferred that both legs are screwed together with a second clamping screw, with the two corresponding end faces of the second clamping screws facing each other. The two second clamping screws can be tightened independently of one another so that the retaining strip remains in its desired position on the housing. Furthermore, it is ensured that a positive connection between the second clamping screws and the housing is achieved on both legs through plastic deformation. The second clamping screws are preferably arranged on a common central axis that runs perpendicular to the longitudinal direction.

[0009] According to the invention, the base has a recess open toward the housing, in which the retaining strip is accommodated. This results in a retaining bracket that is very stable while simultaneously requiring minimal installation space. The recess also provides a rough alignment of the retaining strip relative to the retaining bracket, so that the end face of the first clamping screw rests on the retaining bracket at the designated location. The recess is preferably rectangular in cross-section.

[0010] It is preferable that the depth of the recess be greater than the height of the retaining bar. This allows the base of the retaining bracket to be positioned against the housing, simplifying the installation of the retaining bracket. At the same time, it ensures that the retaining bar is pressed against the housing solely by the first clamping screw and not by the retaining bracket.

[0011] It is preferred that the end face of the first clamping screw protrudes from the retaining bracket at the base of the recess. This results in a particularly firm clamping of the retaining bar.

[0012] It is preferred that the retaining strip has two parallel undercut grooves, which are delimited by a common separating web, with the end face of the first clamping screw resting against a free end of the separating web. Two separate sensors can be accommodated in the two parallel, undercut grooves, which are arranged at a short distance from one another in the longitudinal direction. This allows closely adjacent positions of the linear motion device to be detected. The proposed clamping on the separating web causes a central force introduction into the retaining strip, so that it rests against the housing over its entire surface.

[0013] It is preferred that the retaining strip has an alignment projection arranged such that it can engage with a matching alignment groove on the housing. This is intended to positively align the retaining strip relative to the housing transversely to the longitudinal direction. The alignment projection is preferably arranged on the opposite side of the retaining strip from the first clamping screw.

[0014] It is preferred that the alignment projection be triangular in cross-section. This ensures that the retaining projection engages the alignment groove without play. The retaining strip with the alignment projection is preferably mirror-symmetrical. The tip of the alignment projection is thus located in the center of symmetry and is positioned as far outward as possible on the retaining strip, so that it engages the alignment groove first.

[0015] It is preferred that the width of the recess be greater than the width of the retaining strip. This ensures that the retaining strip is aligned solely by the alignment projection, and is not forced away from the desired position on the housing by the retaining bracket.

[0016] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0017] The invention is explained in more detail below with reference to the accompanying drawings. It shows: Fig. 1 a perspective view of a linear motion device with a holding device according to the invention; and Fig. 2 a cross-section of the linear motion device according to Fig. 1.

[0018] Fig. 1 shows a perspective view of a linear motion device 10 with a holding device 30 according to the invention. The linear motion device 10 is designed essentially according to DE 10 2007 043 391 A1, the entire content of which is incorporated by reference and incorporated into the present application. The linear motion device 10 is designed, for example, as an electric cylinder. However, the present invention can be used for any linear motion device in which a rotor or a cantilever 17 is movable relative to a housing 12 with respect to a longitudinal direction 11.

[0019] The linear motion device 10 has a housing 12 that extends in the longitudinal direction 11 with a constant outer cross-sectional shape. In this case, the outer cross-sectional shape is square with rounded corners. This shape of the outer surface 13 was chosen so that the linear motion device 11 can be easily cleaned. Therefore, the undercut grooves directly on the housing 12, known from DE 10 2007 043 391 A1, were omitted. These can be retrofitted with the holding device according to the invention.

[0020] The housing 12 has a main body 18 made of aluminum by extrusion. It therefore extends with a constant cross-sectional shape in the longitudinal direction 11. Fig. A first end block 19 is attached, in particular screwed, to the left end of the main body 18. The first end block 19 forms a linear sliding bearing for the boom 17, which protrudes from the housing 12 and is movable in the longitudinal direction 11. The boom 17 is designed in the form of a circular cylindrical tube, with a fastening means in the form of a threaded pin provided at its free end.

[0021] On the opposite side, in Fig. 1 right end of the main body 18 is attached a second end block 20, which is a pivot bearing for a threaded spindle (No. 14 in Fig. 2) so that it is rotatable relative to the rotational axis 11a. The rotational axis 11a runs parallel to the longitudinal direction 11. The threaded spindle protrudes from the housing 12 with a drive pin 21, which can be connected to an electric motor for rotational drive, for example.

[0022] At the Fig. 1 The holding device 30 with the holding strip 50 and the two holding brackets 70 is arranged on the upper side of the main body 18. The one-piece holding strip 50 is designed as a separate component, which is manufactured from aluminum using an extrusion process. The holding strip 50 extends with a constant cross-sectional shape in the longitudinal direction 11, wherein in this case it has the same length as the main body 18. However, it is also conceivable to make the holding strip 50 shorter than the main body 18. The holding strip 50 has two undercut grooves 51, wherein a sensor 31 is received in one groove and clamped there. Corresponding sensors are described on page 30 of the catalog “Electromechanical Cylinders EMC,” which was available on June 11, 2014, at https: / / www13.boschrexroth-us.com / catalogs / R310A 3306-EMC2012-02-L.pd.

[0023] The two retaining brackets 70 are identically constructed. They are made of aluminum, for example, from an extruded profile by sawing off short pieces. Therefore, in the longitudinal direction 11, they have the Fig. 2. The two opposite longitudinal end faces of the retaining brackets 70 are flat and run perpendicular to the longitudinal direction 11. In the present case, each of the two ends of the retaining strip 50 is assigned a separate retaining bracket 70, which is arranged at a short distance from the assigned end of the retaining strip 50. However, the retaining brackets 70 according to the invention can be arranged in any number at any location along the longitudinal direction 11. It is understood that only as many retaining brackets 70 are used as are necessary for a sufficiently secure attachment of the retaining strip 50 to the housing 12. The first and second clamping screws 32; 34 are each arranged in the center of the assigned retaining bracket 70 with respect to the longitudinal direction 11.

[0024] Fig. 2 shows a cross section of the linear motion device 10 according to Fig. 1, wherein the sectional plane runs through the screw axes of the first and second clamping screws 32; 34 of a retaining bracket 70. The retaining bracket 70 is U-shaped. It has a base 71 from which two legs 72 protrude vertically. In the center of the base 71 is a rectangular recess 74, in which the retaining strip 50 is received. The width 75 of the recess 74 is slightly larger than the width of the retaining strip 50. Accordingly, the retaining strip 50 is aligned solely by its triangular alignment projection 55, which engages in a clearance-free alignment groove in the housing 12.

[0025] The depth 76 of the recess 74 is greater than the height of the retaining strip 50. Consequently, the bottom 77 of the recess 74 does not rest against the retaining strip 50 even when the base 71 rests with its flat inner surface against the housing 12.

[0026] The retaining strip 50 has a bottom wall 54, which is designed in the form of a flat plate with a constant thickness. Two side webs 53 and a separating web 52 protrude perpendicularly from the bottom wall 54. The separating web 52 is arranged in the center of symmetry of the retaining strip 50, with the side webs 53 each being arranged at the outermost edge of the retaining strip 50. A side web 53, together with the separating web 52, forms an undercut groove 51 in which a sensor 31 can be accommodated. For this purpose, projections pointing towards the center of the groove are provided at the free ends of the side webs 53 and the separating web 52, which projections can be engaged behind by the sensor 31 so that it can be clamped firmly. The outer contour of the retaining strip 50 is rectangular, with the exception of the alignment projection 55.

[0027] In alignment with the separating web 52, the base 71 is penetrated by an internal thread 73 into which the first clamping screw 32 is screwed. The first clamping screw is designed in the form of a threaded pin 36 with a point and hexagon socket according to DIN 914. The end face 33 of the first clamping screw 32, which rests against the separating web 52, is designed in the form of a circular cone, so that it plastically deforms the retaining strip 50 when the clamping force is sufficiently high.

[0028] A second clamping screw 34 is screwed into each of the free ends of the legs 72. For this purpose, the legs 72 are penetrated by an internal thread 73. The second clamping screws 34 are also designed as threaded pins 36 with a pointed end and hexagon socket according to DIN 914. The end face 35 of the second clamping screws 34, which rests against the housing, is therefore also circularly conical. The center axes of the second clamping screws 34 lie on a common axis that runs parallel to the base.

[0029] Inside the housing 12, a threaded spindle 14 is arranged, which is in screw engagement with a threaded nut 15, which surrounds the threaded spindle 14 in a sleeve-like manner. The threaded nut 15 is preferably a ball screw nut. The threaded nut 15 is mounted on the housing-side end of the tubular boom (No. 17 in Fig.1). To prevent rotation of the threaded nut 15 relative to the housing, an anti-rotation device 16 is provided, which has sliding strips on the threaded nut and adapted grooves on the housing 12. List of reference symbols 10 Linear motion device 11 Longitudinal direction 11a Longitudinal axis 12 housings 13 Outer surface of the housing 14 threaded spindle 15 threaded nut 16 Anti-twist device 17 booms 18 main bodies 19 first end block 20 second end block 21 Drive pin of the threaded spindle 30 Holding device 31 Sensor 32 first clamping screw 33 Face of the first clamping screw 34 second clamping screw 35 Face of the second clamping screw 36 threaded pin 50 retaining strip 51 undercut groove 52 Divider 53 side bridge 54 floor wall 55 Alignment projection 70 retaining brackets 71 Base 72 legs 73 internal thread 74 recess 75 Width of the recess 76 Depth of the recess 77 Reason for the recess

Claims

[1] Holding device (30) with at least one sensor (31) and a housing (12) for use in a linear movement device (10), wherein the housing (12) extends with a constant outer cross-sectional shape in a longitudinal direction (11), wherein the holding device (30) has a separate holding strip (50) with at least one undercut groove (51), wherein the holding strip (50) extends with a constant cross-sectional shape in the longitudinal direction (11), wherein the at least one sensor (31) is received in a respectively associated undercut groove (51), characterized byin that the holding device (30) has at least one separate holding bracket (70), wherein the holding bracket (70) has a base (71) which extends transversely to the longitudinal direction (11), wherein the base is screwed to a first clamping screw (32), the end face (33) of which bears against the holding strip (50), wherein the at least one holding bracket (70) has two legs (72) which project perpendicularly from the base (71) so that they encompass the housing (12), wherein at least one leg (72) is screwed to a second clamping screw (34), the end face (35) of which bears against the outside of the housing (12) so that the housing (12) can be clamped between the two legs (72), wherein the base (71) has a recess (74) which is open towards the housing (12) and in which the holding strip (50) is received. [2] Holding device according to claim 1, wherein two or more identical holding brackets (70) are provided, which are assigned to the same holding strip (50). [3] Holding device according to one of the preceding claims, wherein the first and / or the second clamping screw (32; 34) is each formed by a threaded pin having a conical end face (33; 35), wherein the threaded pin (36) is screwed into an associated internal thread (73) on the retaining bracket (70). [4] Holding device according to one of the preceding claims, wherein both legs (72) are screwed to a second clamping screw (34), wherein the two corresponding end faces (35) of the second clamping screws (34) point towards each other. [5] Holding device according to one of the preceding claims, wherein the depth (76) of the recess (74) is greater than the height of the holding strip (50). [6] Holding device according to one of the preceding claims, wherein the end face (33) of the first clamping screw (32) protrudes from the holding bracket (70) at the base (77) of the recess (74). [7] Holding device according to one of the preceding claims, wherein the holding strip (50) has two parallel undercut (51) grooves which are delimited by a common separating web (52), wherein the end face (33) of the first clamping screw (32) rests against a free end of the separating web (52). [8] Holding device according to one of the preceding claims, wherein the holding strip (50) has an alignment projection (55) which is arranged such that it can engage in a matched alignment groove on the housing (12). [9] Holding device according to claim 8, wherein the alignment projection (55) is triangular in cross section. [10] Holding device according to claim 8 or 9, wherein the width (75) of the recess (74) is greater than the width of the holding strip (50).

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