Mounting bracket for a proximity switch

Abstract

Mounting bracket for a proximity switch (1) having a sensor surface (3) on a front end face of its cylindrical housing and a mounting structure (4) behind it, with fastening means (12, 12') for attaching a base body (6) to a component or the like, with a receiving cavity (10) for receiving the proximity switch (1), with a locking element (7) having a restraint structure (9, 9'), which is pivotable from a release position, in which the proximity switch (1) can be removed from the receiving cavity (10) in the direction of the cylindrical axis (A), about a pivot axis (14) into a locking position, in which the restraint structure (9, 9') interacts with the mounting structure (4) and at least inhibits the removal of the proximity switch (1) from the receiving cavity (10), characterized in that the interaction between the restraint structure (9, 9')9') and fastening structure (4) the creation of a positive locking connection between fastening structure (4) and restraint structure (9, 9'), and that the locking element (7) has a spring element (24) which exerts a radial force on the housing of the proximity switch (1).

Description

Field of TechnologyThe invention relates to a holder for a cylindrical proximity switch, with which the proximity switch can be fastened to a component or otherwise.Prior ArtDE 10 2008 006 746 A1 describes a holder for a cylindrical proximity switch, in which a bent sheet has an opening through which the cylindrical body of the proximity switch is inserted. The fastening is effected with nuts which bear on both sides on the broad sides of the limb and are screwed onto an external thread of the proximity switch.A holder for fastening proximity switches is also described in DE 295 09 100 U1 and DE 20 2006 003 916 U1.DE 199 37 332 A1 describes a holder for a cylindrical sensor, in which the sensor is secured in a clamping manner in a cylindrical receiving cavity.Holders for proximity switches are also known from DE 101 38 161 C1 and DE 101 47 023 A1.DE 199 00 876 C1 discloses a fastening device with a fixing body pivotably mounted in the base body, which fixing body has a clamping element with a bead-like bulge. When the fixing body is pivoted, a proximity switch inserted into the recess is pressed radially against the wall by the bulge and is fixed exclusively in a force-locking manner.DE 203 01 144 U1 discloses a fastening device with a fastening base, into the receiving opening of which an electrical device with connecting pieces can be inserted. For locking, a pivotable locking pivot lever is provided which carries a wedge. This wedge engages positively in a peripherally encircling groove of the connecting piece during pivoting.SUMMARY OF THE INVENTIONThe invention is based on the object of specifying a holder with which a cylindrical proximity switch can be fastened to a component or in another way, wherein the proximity switch can be connected to the holder in a defined position and can be detached again using simple means.The object is achieved by the invention specified in the claims. The dependent claims represent not only advantageous developments of the invention, but also independent solutions to the object.A proximity switch of the type in question has a cylindrical housing with two end faces pointing away from one another. A front end side forms a sensor surface. The housing has a fixing structure at a position rearward of the sensor surface. This attachment structure may be protrusions, steps, threads, recesses, shoulders, or other three-dimensional structures that can engage with restraining structures to hold the sensor in an intended position, wherein the restraining structures can likewise be protrusions, recesses, threads, or other three-dimensional surface designs. The holder according to the invention has a restraining structure which interacts with the fastening structure in such a way that the proximity switch is at least inhibited from being removed from a receiving cavity of the holder. The restraining structure and the fastening structure cooperate in such a way that the removal of the proximity switch from the cavity is prevented. The fastening structure and the restraining structure cooperate with one another to form a positive connection. It can be provided that the proximity switch has an annular step which surrounds a connection element, for example a plug connector or a cable protruding from the rear end face. According to a first aspect of the invention, the holder for such a sensor has fastening means, with which the holder and in particular a base body of the holder can be fastened to a component, for example a mounting plate or the like. The holder according to the invention can have one or more of the features described below. The base housing has a cylindrical receiving cavity adapted to the shape of the housing of the proximity switch. The housing has a stop against which the proximity switch is supported. The receiving cavity has a bottom. The sensor surface of the proximity switch is supported on the ground. The bottom may have an opening. The opening can, however, also be closed. The sensor surface may be planar. The bottom of the receiving cavity is preferably likewise planar and is preferably formed by a thin-walled section of the base body. The holder has a locking projection which is associated with a locking element. The locking element can be pivoted from a release position about a pivot axis into a locking position. In the release position, the proximity switch can be pulled out of the receiving cavity in the direction of the axis of the receiving cavity. In the locking position, this is prevented since the fastening structure is formed here by a step and the restraining structure is formed by a locking projection, wherein the step is surrounded by the locking projection. The holder characterized above has the following supplementary and in particular optional features, which can be realized both individually and in combination with one another: the locking element is held in the locking position by means of latching means. The latching means can have a latching projection. This can be assigned to the base body. In the locking position, the latching projection lies in a latching recess of a latching tab, which is preferably assigned to the locking element. The latching tab can have spring-elastic properties, so that it can snap over the latching projection by elastic bending and can also be raised over the latching projection again by a corresponding under grip in order to pivot the locking element from the locking position into the release position. The pivot axis about which the locking element can be pivoted preferably runs parallel to the cylinder axis of the receiving cavity. The locking element can form part of a wall of the receiving cavity. For this purpose, the receiving cavity preferably forms a radial opening. The opening can be formed by a U-shaped cut extending in the axial direction. The locking element functionally also forms a closure element, with which the opening is closed in the locking position. A closure part of the locking element can completely fill the opening in the locking position, so that a wall section of the closure part facing the opening is part of the receiving cavity running on a cylinder jacket wall. The opening can extend from an upper open edge of the receiving cavity as far as a pot-shaped end section of the receiving cavity, which also forms the base of the receiving cavity. The receiving cavity may have a circular cross section. The locking projection can be seated on a free end of an extension extending in the direction of the cylinder axis. The extension can be an axial extension of the closure part. The fastening means can be formed by fastening screw passage openings which have screw head receiving chambers, so that the fastening of the base body to a component, for example to a mounting plate, is possible by means of cylinder head screws. The screwing tool inlet openings of the screws point in the direction of the axis of the receiving cavity. The fastening screw passage openings are preferably located on the wall section of the receiving cavity opposite the opening, so that the screwing tool for rotating the screws can be inserted through the wall opening, which is open in the release position and closed in the locking position. The sensor can be connected to the holder in a simple manner and without the use of tools in a reproducible manner. It can be positioned precisely in position, since the position of the sensor surface is predetermined by the position of the bottom of the receiving cavity. When the closure element is closed, that is to say when the locking element is locked, the locking projection rests with an exact fit on the step. For this purpose, the locking projection can have a slight inclination and, owing to its elasticity, can be slightly deformed, so that it exerts an axial pressure on the annular step, with which the sensor surface is pressed against the bottom of the receiving cavity. It can be an inductive proximity switch or a capacitive proximity switch. The housing is made of a dielectric material, in particular plastic. The material accumulation forming the end face of the base body forms a thin-walled housing section with an outer wall which has a circular outline and runs parallel to the surface of the base. In a preferred embodiment, the base body is fastened to a mounting plate. The mounting plate can have elongated holes, with which it can be fastened in another way, for example on a machine part. The invention also relates to a capacitive or inductive proximity switch which is inserted into a holder of the type described above. An inductive proximity switch may be used having a sensing surface of a ceramic material. This can be, in particular, a ceramic cover with which a steel housing having a threaded sleeve is closed. The cavity may be cylindrical. However, it can also have a shape deviating therefrom. The cavity may have at least a portion in which it is closed over its entire periphery. However, the cavity can also be formed only by a groove of C-shaped cross section which is open on both sides, wherein a stop is preferably provided on which the proximity switch can be supported. The proximity switch is preferably seated between two stops, wherein one of the two stops can be brought into a locking position and out of a locking position again. The stop can be an annular shoulder in the region of the base, on which shoulder the end face of the proximity switch can be supported. In one variant, the step forming a locking projection can be omitted. In this variant of the above-described holder, the restraining structure is formed by the closure element which closes an opening in the locking position. The inner side of the closure element can have the restraining structure, which preferably forms at least one locking projection, which engages in an external toothing of the proximity switch. The restraining structure can, however, also be formed by a toothing, in particular a toothed strip, wherein the closure element forms the toothed strip. The teeth of the toothing can have oblique flanks. The closure element has a spring element which, in the locking position, rests with a radial force on the outer wall of the proximity switch. In a variant of the invention, this radial force can be sufficiently large to prevent the proximity switch from being pulled out in a frictionally locking manner in the receiving cavity. In this variant, the fastening structure and the restraining structure act frictionally with one another. However, it is also provided that the spring force of the spring element radially loads the toothed strip or the projection in such a way that the proximity switch is inserted in the receiving cavity without axial play. The receiving cavity can be open on both sides. The proximity switch can be axially displaced back and forth in the receiving cavity when the locking element assumes its release position. By displacing the locking element into the locking position, the proximity switch is fixed in an axial position. The proximity switch can protrude with its two ends out of the receiving cavity. In a further aspect of the invention, an adapter is provided. This adapter makes it possible to fix proximity switches with a diameter smaller than the diameter of the receiving cavity from the same holder. The adapter is in the form of a sleeve and in particular a sleeve which is open at the gap, wherein a rib extends along the gap, which rib is connected to the annular body via a spring web. The rib forms a restraining structure which cooperates with the fastening structure of the proximity switch. In a preferred embodiment of the invention, the rib has on its outwardly facing side a retaining structure which cooperates with the fastening structure of the holder. On its radially inwardly directed side, the rib has the restraining structure. When closing the locking element, the spring element can thus exert a radial force on the spring web, so that its restraining structure can interact with the fastening structure of the proximity switch. Inclined flanks of a toothing preferably abut inclined flanks of a counter toothing. Such an arrangement forms a holder with a first restraining structure, which interacts with a holding structure of the adapter and interacts in particular in a form-fitting manner, wherein the adapter forms a second restraining structure, which interacts in particular in a form-fitting manner with the fastening structure of the proximity switch. Preferably, the two restraining structures lie in a common sectional plane through the axis of the receiving cavity. The second restraining structure is preferably assigned to a rib which has on its side of the holding structure opposite the second restraining structure.Brief Description of the DrawingsExemplary embodiments of the invention are explained below with reference to the attached drawings. The following are shown: FIG. 1 shows a first perspective illustration of a holder in the open state, in which a locking element 7 is located in a release position with respect to a base body 6, FIG. 2 shows a representation similar to FIG. 1, but with proximity switch 1 inserted into a receiving cavity 10 of base body 6, FIG. 3 is a view similar to FIG. 2, but with the locking element 7 pivoted into the locking position, FIG. 4 is a plan view of a holder according to FIG. 1 holding a proximity switch 1, FIG. 5 is a sectional view taken along the line V--V in FIG. 4, FIG. 6 is a sectional view taken along the line VI--VI in FIG. 4, FIG. 7 is a sectional view taken along the line VII--VII in FIG. 5, FIG. 8 shows an illustration according to FIG. 3, but with a base body 6 fastened to a mounting plate 22, FIG. 9 shows a representation according to FIG. 5 of a second exemplary embodiment, FIG. 10 shows an adapter of a third exemplary embodiment, and FIG. 11 shows the third exemplary embodiment in a representation according to FIG. 5.DESCRIPTION OF THE EMBODIMENTSThe holder shown in the drawings is used for holding an inductive or capacitive proximity switch 1. the proximity switch 1 has a substantially cylindrical housing with a front end side which forms a sensor surface 3 and a rear end side which forms an annular step 4 which surrounds a connection element 5. A cable can be connected to the connection element 5. The outer wall of the proximity switch 1 is a cylindrical wall 2.The holder consists of a base body 6 made of plastic and a locking element 7, which also forms a closure element, which is assigned to the base body 6 so as to be pivotable about a pivot axis 14. The pivot axis 14 extends parallel to an axis A of the cylindrical receiving cavity 10.In a locked state shown in FIGS. 3, 4, 5, 6 to 7, the locking element 7 is latch-connected to the base body 6, so that it cannot be brought into the release position shown in FIG. 1 without releasing latching means? 17, 18, 19. In the locking position, the receiving cavity 10 forms a circular cylindrical blind bore with wall sections 11, 16' running along a cylinder lateral surface and a flat base 13. The diameter of the receiving cavity 10 is a few times larger than the diameter of the cylindrical wall 2 of the proximity switch 1. the proximity switch 1 can be inserted into the receiving cavity 10 in the release position of the locking element 7 (FIG. 1 ) (see FIG. 2 ). If the locking element is brought into the closed position shown in FIG. 3, a locking projection 9 projects beyond the rear end side and in particular the annular step 4 of the proximity switch 1, so that the proximity switch 1 is prevented from being pulled out of the receiving cavity 10. The surface section of the locking projection 9 resting on the annular step 4 or the edge of the annular step 4 can be a bevel.The locking projection 9 is seated on a free end of an extension 8 which can be elastically bendable, so that the contact surface of the locking projection 9 can also be supported on the annular step 4 in a spring-biased manner and can thereby develop a force with which the sensor surface 3 is loaded against the bottom 13 of the receiving cavity 10.The locking element 7 forms a type of door. The door forms a closure element 7, with which an opening of the wall of the receiving cavity 10 can be closed. For this purpose, the locking element 7 forms a spring element 24, which is designed as a spring tongue and, in the locking position, bears with a radial force against the wall of the proximity switch 1.The opening 10 is a slot beginning at the upper edge 21 of the receiving cavity 10 and having slot walls running parallel to one another. The slot forming the opening 15 ends at a lower pot section 20, in which the cylinder wall of the receiving cavity 10 is closed all the way round and which pot section 20 forms the base 13.On one side of the slot-shaped opening 10 there is a pivot bearing which is formed by a solid axis which forms a pivot axis 14 which runs parallel to the figure axis of the receiving cavity 10. The pivot axis 14 extends parallel to the slot wall of the opening 15.On the side of the opening 15 opposite the pivot axis 14, the base body 6 forms a radially outwardly protruding latching projection 17. The locking element 7 forms a resiliently bendable latching tab 19 with a latching recess 18. In the locking position, the latching projection 17 engages in the latching recess 18. By engaging under the latching tab 19, the latching tab 19 can be raised over the latching projection 17.The locking element 7 forms a closure element 16 which, in particular with the spring element 24, forms a wall section 16' which runs on a cylinder surface. In the locking position, a section of the closure element 16, in particular the spring element 24, fills the opening 15. The closure element 16 has narrow sides which, in the locking position, bear against narrow sides of the opening 15.A portion of the cylindrical wall 11 opposite the opening 15 forms one or more fastening openings 12, 12'. At least some of the openings 12 are located within the receiving cavity 10 and can be reached by a tool, in particular a blade of a screwdriver, only when the locking element 7 assumes its release position and is pivoted out of the opening 15. The mounting apertures 12, 12' may have diameter enlarged portions for receiving a cylinder head bolt. A screwdriver can engage in the screwing tool inlet opening of the cylinder head bolts, which screwdriver is passed through the opening 15.A fastening opening 12'-in relation to the cylinder axis-is situated diametrically opposite the locking projection 9.FIG. 8 shows a combination of a proximity switch 1 with a holder and a mounting plate 22, and the base body 6 is connected to the mounting plate 22 by means of screws which are inserted through the fastening openings 12, 12' and are provided with nuts. The mounting plate 22 has two slots 23 extending parallel to one another, with which the mounting plate 22 can be fastened in another way.The invention proposes in particular a holder with which a proximity switch 1 can be exchanged without the use of tools, wherein the position of the proximity switch 1 remains unchanged. In particular, the level at which the sensor surface sits does not change when a proximity switch 1 is replaced. If the rear end side of the proximity switch 1 is additionally subjected to spring force by the locking projection 9, a rattle-free mounting is achieved. The latching connection elements 17 to 19 ensure a secure fixing of the locking element 7 in the locking position, but at the same time permit the locking element 7 to be opened without a tool. During assembly, the proximity switch 1 only has to be inserted into the receiving cavity 10 and the locking element 7 has to be pivoted about the pivot axis 14 into the locking position. The latching takes place automatically. The spring element 24 also contributes to the rattle-free mounting, which presses the housing of the proximity switch 1 in the radial direction against the wall 11 opposite the wall 16'.In a variant of the invention, the extension 8 and the locking projection 9 carried by it can be omitted. The spring element 24 acts upon the outer wall of the proximity switch with a sufficient frictional force, so that the proximity switch 1 is constrained with a sufficient frictional force within the receiving cavity 10.To improve the gripping of the proximity switch 1, it is provided in the exemplary embodiment shown in FIG. 9 that a toothing 25 engages in the external toothing 26 of the proximity switch 1. As in the first exemplary embodiment, the external toothing 26 forms a projection, which engages behind a shoulder. Whereas in the first exemplary embodiment the shoulder is formed by an annular step, in the exemplary embodiment shown in FIG. 9, the shoulder is formed by the tooth flanks of the toothing 26 which are engaged behind by the teeth of the toothing 25. Preferably, inclined flanks of a toothing abut inclined flanks of a counter toothing. At least one tooth of the toothing 25 forms a projection 9 which has oblique flanks which meet in a vertex line and which engage in the manner of a wedge in the oblique flanks of the external thread 26, in order thereby to axially secure the proximity switch 1.In the exemplary embodiment shown in FIG. 25, the receiving cavity 10 furthermore does not have a bottom, but is open on both sides over the full cross-sectional width, so that the proximity switch 1 can be displaced axially within the receiving cavity 10. The displaceability of the proximity switch 1 within the receiving cavity 10 is, however, inhibited and preferably prevented when the toothing 25 engages in the toothing 26.Since the toothing 25 is part of a spring element 24, which is tensioned when the closure element 7 is closed, the proximity switch 1 lies in the receiving cavity 10 without rattling and is held in position.FIG. 10 shows an adapter 28 which can be inserted into the receiving cavity 10 instead of a proximity switch 1. The adapter 28 has a substantially circular cross-section, but the circle is not closed. An open-split annular body 32 is adjoined by a rib 33. The rib 33 is connected to the annular body 32 via a spring web 30. The axially extending rib 33 carries on its radially inwardly directed side a toothing 25'. On the radially outward side, the rib 33 carries a toothing 29.If the adapter 28 is inserted into the receiving cavity 10, as shown in FIG. 11, the rib 33 lies in a radial position in which the spring element 24 or the toothing 25 is located. The toothing 25 then engages in the toothing 29 in order to fix the adapter 28 axially in the receiving cavity 10. A proximity switch 1 with a correspondingly smaller diameter can be inserted into the receiving cavity 34 of the adapter 28. The toothing 25' of the rib 33 now engages in the external toothing 26 of the proximity switch 1 when the closure element 7 is closed. The spring web 30 is tensioned in this case. In the non-tensioned state, the spring web 30 holds the toothing 25' in a disengagement position from the external toothing 26 of the proximity switch 1.

Claims

Holder for a proximity switch (1) having a sensor surface (3) with a front end face of its cylindrical housing and a fastening structure (4) at the rear thereof, having fastening means (12, 12') for fastening a base body (6) to a component or the like having a receiving cavity (10) for receiving the proximity switch (1), having a locking element (7) having a restraining structure (9, 9') which can be pivoted about a pivot axis (14) from a release position, in which the proximity switch (1) can be removed from the receiving cavity (10) in the direction of the cylinder axis (A) of the latter, into a locking position, in which the restraining structure (9, 9') cooperates with the fastening structure (4) to at least inhibit removal of the proximity switch (1) from the receiving cavity (10), characterized in that, the interaction between the fastening structure (9, 9') and the fastening structure (4) is the creation of a positive connection between the fastening structure (4) and the fastening structure (9, 9'), and the locking element (7) has a spring element (24), which exerts a radial force on the housing of the proximity switch (1).Holder according to claim 1, characterised in that the locking element (7) is held in the locking position by means of latching means (17, 18, 19) and in particular the latching means have a resilient latching tab (19) which has a latching recess (18), in which a latching projection (17) engages in the locking position.Holder according to one of the preceding claims, characterized in that the pivot axis (14) runs parallel to the cylinder axis (A) of the receiving cavity (10).Holder according to one of the preceding claims, characterized in that the locking element (7) forms a closure element with which an opening (15) of the wall of the receiving cavity (10) is closed in the locking position, which opening (15) is open in the release position.Holder according to one of the preceding claims, characterized in that the locking element (7) forms a part (16') of a wall (11) of the receiving cavity (10) running on a circumferential surface of a circular cylinder.Holder according to one of the preceding claims, characterized in that the restraining structure (9, 9') forms a locking projection (9, 9') and the fastening structure (4) forms a shoulder interacting with the locking projection (9, 9').Holder according to Claim 6, characterized in that the locking projection (9, 9') engages in an external toothing (26) of the proximity switch (1).Holder according to one of claims 6 or 7, characterised in that the locking projection (9, 9') is formed by one or more teeth of a toothing (25, 25').Holder according to claim 7, characterised in that a first restraining structure (9) is formed by the spring element (24).Holder according to one of the preceding claims, characterized in that the receiving cavity (10) is open on both sides in such a way that the proximity switch (1) in the release position can be displaced axially through the receiving cavity (10).Holder according to one of the preceding claims, characterized byan adapter (28) which can be inserted into the receiving cavity (10) and has a retaining structure (29) with which a first restraining structure (9) of the holder, cooperating with it, at least inhibits removal of the adapter (28) from the receiving cavity (10), wherein the adapter (28) has a second restraining structure (9') which, cooperating with the fastening structure (4), at least inhibits removal of the proximity switch (1) from a cavity (31) of the adapter (28).Holder according to claim 11, characterised in that the restraining structure (9') of the adapter (28) is formed by a projection and / or a toothing (25'), wherein the restraining structure (9') of the adapter (28) is assigned to a spring web (30), which is elastically connected to an annular body (32) surrounding the cavity (31).Holder according to one of the preceding claims, characterized bya stop on which the proximity switch (1) is supported, wherein the stop is preferably formed by a base (13) of the receiving cavity (10) on which the sensor surface (3) is supported, wherein the base (13) is open or closed and / or the opening (15) extends from a pot section (20) forming the base (13) of the receiving cavity (10) as far as an upper edge (21) of the receiving cavity (10), wherein the base (13) in particular consists of a continuously closed, thin, planar material accumulation of the base body (6) made of plastic and the outer side of the base body (6) opposite the inner side of the base (13) is in particular a planar circular surface and / or wherein the fastening structure (4) is formed by a step, which is an annular step around a remote connecting element (5) of the proximity switch (1).Holder according to one of Claims 6 to 9, characterized in that the locking projection (9) is located at the free end of an extension (8) extending in the direction of the cylinder axis (A).Holder according to one of the preceding claims, characterized in that the fastening means (12) are designed as fastening screw passage openings with screw head receiving chambers, at least one fastening screw passage opening being located on the side of the wall (11) opposite the opening (15) of the wall of the receiving cavity (10).

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