Form-fit adjustment for casters

Abstract

The present invention relates to a form-fitting fixing device (14) for a caster (1) with a running wheel (2), a fork (3) and a rotation prevention engagement part (43), in which the running wheel (2) of the caster (1) can be prevented from rotating about a geometric running wheel axis (y) via the rotation prevention engagement part (43), and further characterized in that a first spring (58) acts on the rotation prevention engagement part (43) for displacement of the rotation prevention engagement part (43) from a start position to an engagement position, the form-fitting fixing device (14) is characterized in that the first spring (58) is attached to a pivotable lever part (41), the first spring (58) forms a lever arm (68), with the displacement of the rotation prevention engagement part (43) to the engagement position a second spring (59) attached to the lever part (41) can be tensioned to return to the start position, and the first spring (58) is stronger than the second spring (59).

Description

[Technical field]

[0001] The present invention relates to a form-fitting locking device for a caster comprising a running wheel, a fork and a rotation-preventing engagement part, the running wheel of the caster being prevented from rotating about a geometric running wheel axis via the form-fitting locking device, and further wherein a first spring acts on the rotation-preventing engagement part to move the rotation-preventing engagement part from a starting position to an engaged position.

[0002] The invention also relates to a form-fitting locking device for a caster with a running wheel, a fork and a rotation-preventing engagement part, the running wheel of the caster can be prevented from rotating about a geometric running wheel axis via the form-fitting locking device, and the rotation-preventing engagement part can be actuated via a lever part for displacing from a start position to an engagement position and / or from the engagement position to the start position, the lever part being actuable by a tappet. [Background technology]

[0003] Form-fit locking devices of the type in question are known, in particular for running wheels and forks, if applicable for castors with additional mounting pins. The running wheels of the castor can be prevented from rotating with respect to the geometric running wheel axle via the form-fit locking device. In the solutions known for this purpose, the rotation-blocking engagement parts, which are arranged, for example, on the fork or on the mounting pin side, are fully locked in the engagement position with at least one counter-engagement part on the running wheel side. In this connection, it is further known to provide teeth on the running wheel side in the circumferential direction with respect to the running wheel axle, with which the rotation-blocking engagement part can engage in order to activate the form-fit locking device, in order to form the counter-engagement part. In this connection, it is also known to pretension such rotation-blocking engagement parts with a spring in the engagement position and, if applicable, also in the disengaged position.

[0004] In this connection, reference is made, for example, to EP 1 339 636 (EP 1 339 636). Thus, a caster, here a steering caster, is known which, in addition to the rotational mobility of the running wheels, also has a pivotal mobility of the pivot axis of the caster fork, in which the rotation-preventing engaging part is displaceable essentially transversely with respect to the mounting pin axis of the caster in order to interact with the gear rim of the running wheels and is therefore also oriented correspondingly with respect to a line which is oriented horizontally in normal use. A spring acting on the engaging part acts on the rotation-preventing engaging part at least in the engaged or ready-to-engage position.

[0005] In addition, it is further known, for example from the aforementioned US Pat. No. 5,999,944, to act on a lever part of a form-fit fastening device via a tappet, which is guided, for example, in the region of the mounting pin of the castor and displaceable along the mounting pin axis, in order to displace a rotation-preventing engaging part from a starting position to an engaged position and / or vice versa.

[0006] A form-fitting locking device for a caster is known from US Pat. No. 5,399,663 (Patent Document 4), in which a first spring acts on a linearly displaceable tappet which in turn acts on a lever part which displaces a rotation-preventing engagement part into an engaged position against the action of a second return spring.

[0007] In a form-fitting fastening device known from DE 10 200 03 133 A1 a first spring acts against the lever part for a linear displacement of the lever part, and a second spring arranged to act on the lever part is linearly displaced correspondingly to the lever part upon tensioning or releasing of said spring.

[0008] Reference is further made to US Pat. No. 5,399,633 (US Pat. No. 5,499,652) as prior art, in which in the known form-fit fastening device a linearly displaceable engagement part is provided which can be displaced into an engagement position by a wedge gear. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2019 / 053004 [Patent Document 2] US Patent No. 11065913 [Patent Document 3] International Publication No. 2012 / 171816 [Patent Document 4] US Patent Publication No. 2014 / 0109342 [Patent Document 5] German published patent application no. 102014113460 [Patent Document 6] German Utility Model No. 8915173 [Patent Document 7] US Patent No. 5,133,106 Summary of the Invention [Problem to be solved by the invention]

[0010] In view of the above-mentioned prior art, particularly US Pat. No. 5,399,633, the present invention is concerned with the problem of advantageously constructing a form-fitting fastening device of the type in question. [Means for solving the problem]

[0011] In the first idea of ​​the present invention, a possible solution to the problem is proposed for a form-fit fixing device, noting that a first spring is attached to the pivotable lever part, the first spring forms the lever arm, and upon displacement of the anti-rotation engagement part to the engagement position a second spring attached to the lever part can be tensioned to return to the starting position, the first spring being stronger than the second spring.

[0012] The anti-rotation engaging part is actuated for displacement from the starting position towards the engaged position by a lever arm which is part of a first spring and which is designed to be elastic in itself, the spring force of the first spring forming this lever arm being selected to be sufficiently large so that the displacement of the anti-rotation engaging part towards the engaged position tensions the second spring, When the load acting on the lever part ceases, it is feasible for the lever part, and thereby preferably also the anti-rotation engaging part, to return to the starting position via the tensioned second spring.

[0013] During normal operation of the form-fit locking device, the anti-rotation engaging part can engage without resistance with the counter-engaging part on the running wheel side, and the lever arm of the lever part, formed by the first spring, acts substantially rigidly on the anti-rotation engaging part for the displacement of the anti-rotation engaging part. In the case of such normal operation, accordingly (initially) only the spring force of the weaker second spring is overcome, and a pretension force is built up for returning the lever part over the course of this displacement. In addition, reduced shifting forces are thereby advantageously obtained compared to the known prior art.

[0014] Preferably, only in the case where the rotation preventing engaging part cannot immediately engage with the corresponding counter engaging part of the running wheel, for example in the situation where the engaging tooth of the rotation preventing engaging part collides with the engaging tooth of the counter engaging part, the first spring forming the lever arm in addition to the second spring also comes into operation. The spring force of the first spring thus accumulated causes an automatic displacement of the rotation preventing engaging part to the rotation preventing engagement position as soon as the running wheel and thus the counter engaging part are rotated by a further small angle, so that the engaging tooth of the rotation preventing engaging part can fall into the tooth valley between the engaging tooth of the counter engaging part.

[0015] As a further original idea, another possible solution which is independent and important both in itself and alternatively in combination with the previously mentioned solution and also in view of the embodiments described below, is proposed as a form-fitting fixing device, focusing on the fact that a tappet with tappet extensions of different lengths is formed in the shape of a fork, one tappet extension being arranged to act on a lever part.

[0016] For example, if the tappet is configured substantially in a U-shape, the tappet extensions will form legs of the U oriented substantially parallel to one another and connected to one another via a cross bar of the U. A portion of the running wheel may extend between the legs of the U.

[0017] Typically and preferably, the anti-rotation engagement part is capable of linear displacement from a start position to the engagement position and back, and more preferably originates substantially from the geometric running axis along a horizontal line in the normal use position of the caster.

[0018] The U-shaped legs of the tappets forming the tappet extensions are selected to be of different lengths, starting from the crossbar of the connecting U, in their substantially vertical extension in the normal position of use. They are therefore preferably designed such that in the operative positioning position, only one of the two tappet extensions acts on the lever part of the form-fitting fastening device. This advantageously provides the possibility of arranging the tappets on castors with different running wheel diameters. The tappets are preferably arranged according to the corresponding arrangement of the tappets on the castor, so that in the case of a smaller running wheel diameter, the shorter tappet extension and, conversely, in the case of a larger running wheel diameter, the longer tappet extension are oriented to act on the lever part of the form-fitting fastening device.

[0019] In the normal orientation of the caster, the tappet extensions extend substantially vertically, more preferably along and on either side of the mounting pin axis, which further preferably passes substantially through the center of the cross bar of the aforementioned U-shape of the tappet. By rotating the tappet arrangement 180 degrees about the mounting pin axis, only the shorter or longer tappet extensions are positioned to act on the lever component of the form-fit fixing device.

[0020] The same components can therefore be used, in particular with regard to the elements forming the mounting pins and the elements forming the form-fitting fastening device, as well as with regard to the tappets, except for the forks and running wheels, in a particularly advantageous manufacturing technique method, to manufacture castors with different running wheel diameters.

[0021] The features of the above-mentioned independent claims may be important both on their own and in any combination with one another, and additional features of one independent claim may be combined with the features of one or more other independent claims and also additionally with only the individual features of one or more additional independent claims.

[0022] A possible solution to the problem thus arises in that the first spring is formed by the lever arm of the lever part, that with the displacement of the anti-rotation engagement part the second spring can be tensioned to return to its starting position, and that the first spring is stronger than the second spring, in which case it can further be provided that the tappet with tappet extensions of different lengths is formed in the shape of a fork and is arranged in such a way that only one tappet extension acts on the lever part.

[0023] An independent inventive idea can already be seen in the first described solution, in particular in regard to the initial obstruction of the engaging tooth to falling into the tooth valley, that the lever arm is designed as a spring arm. In that case, it can preferably be provided that with the displacement of the anti-rotation engaging part into the engaging position, the second spring can be tensioned to return to the starting position and / or that the first spring is stronger than the second spring. In addition, however, the additionally described features can additionally be implemented in relation to the first described solution, individually or in combination.

[0024] Additional features of the invention are often described below and depicted in the figures in the preferred allocation to the subject matter of claim 1, to additional independent claims or to features of other claims, but they are each important independently or in their allocation to only individual features of claim 1 and / or to the additional independent claims or to the respective additional claims.

[0025] Advantageously, both the first and the second spring may be substantially detensioned in the starting position of the form-fit locking device, e.g. in the non-engaged position of the anti-rotation engagement part. As a result of this preferred embodiment, at least one of the two springs, in particular the second spring, is loaded only and initially in the process of achieving and maintaining the engaged position. As for the first spring, it may additionally also be substantially detensioned in the engaged position.

[0026] The first spring can be designed as a torsion spring. In another embodiment, the second spring can also be designed as a torsion spring. Such a torsion spring usually comprises two spring legs, one of which acts on a damped object, a rotation-blocking engagement part or a lever part, and the other of which rests on a substantially stationary support member.

[0027] Thus, according to one preferred embodiment, the second spring may furthermore act between the lever part and a mounting part fixed to the fork. The mounting part may be a separate part from the fork and may be fixed to the fork. Furthermore, the mounting part may thereby be designed in such a way that it can be used both with forks for receiving running wheels with a larger diameter and with forks for receiving running wheels with a relatively smaller diameter. Correspondingly, the retaining element may be part of the overall form-fitting fastening device and is designed to fit both running wheel diameters as described above.

[0028] Preferably, both springs, i.e. both the first and the second spring, act on one end of the lever part, in particular via a spring leg, about the geometrical rotation axis of the lever part, the spring legs of the two springs may, if preferred and applicable, act on the lever part in opposite directions.

[0029] A first, stronger spring may act alone between the lever part and the anti-rotation engagement part, as is also preferred. During a rotational / pivotal displacement of the corresponding lever part, a winding of this first spring with the lever part also preferably occurs, so that the lever arm with the elasticity of the first spring acting on the anti-rotation engagement part may furthermore be subjected to a corresponding counterload, for example in case of incorrect engagement of the teeth (tooth to tooth position), accumulating a restoring force of the spring via the anti-rotation engagement part.

[0030] In other embodiments, the second spring, in particular in the region between its spring legs, may be wrapped around a mounting pin of the mounting part, for example by means of a coil portion, more preferably this mounting pin being centered on the geometric pivot axis of the mounting part.

[0031] In one possible development, the first spring can be guided in a groove of the lever part, in particular by means of a spring leg assigned to the lever part, whereby the groove can be designed with respect to its extent to be adapted to the diameter of the spring transversely to the longitudinal extension of the received spring leg, the spring leg can be inserted substantially loosely in this groove and, if applicable, can also be accommodated in a clamping manner.

[0032] The lever part may also have a total of two drive ends, whereby the drive ends may, as is also preferred, be formed by a rigid stop part acting on the rotation prevention engagement part in the direction towards the start position, and furthermore the catch member of the rotation prevention engagement part may be substantially captured between the drive end of the lever part and a resilient lever arm acting in the direction towards the engagement position.

[0033] In one preferred embodiment, the other drive end of the lever part, which may be designed to be located substantially opposite the aforementioned first drive end with respect to the geometrical rotation axis of the lever part, interacts directly with the tappet, and as a whole the form-fitting fixing device is operable via the aforementioned tappet.

[0034] In a preferred embodiment, the mounted tappet guided in the mounting pin and / or in the fork can be actuated on the mounting pin side by a switching tappet which preferably extends along a pin axis which runs substantially vertically during normal operation of the caster and further preferably is linearly displaceable along this pin axis, so that the switching tappet can be actuated in the usual way via a switching cam accommodated in the mounting pin to switch at least between the start position and the engagement position of the anti-rotation engagement part, but additionally, if applicable and also preferred, to act on the pivot locking device of the fork.

[0035] The tappet may interact with a second spring, which loads the tappet in the direction of the starting position, so that the form-fitting locking device, in particular the anti-rotation engaging part, rests in the starting position. The load on the tappet, which acts on the anti-rotation engaging part and displaces it into the engaged position, is applied against the restoring force of the second spring. In addition, the second spring may thereby have a support fixed to the fork and, if applicable, in the region of a mounting part fixed to the fork. The second spring may furthermore preferably be designed in the form of a hairpin spring.

[0036] The shift tappet on the mounting pin side is provided with a separate first return spring, which is preferably arranged in the region of the mounting pin and is independent of the tappet, whereby this can be, for example, a conventional cylindrical compression spring, which can be arranged concentrically relative to the geometric mounting pin axis.

[0037] In this context, it is also possible to design the castor with only one return spring. The (second) return spring, which preferably acts directly on the tappet, can therefore also be used to return the switching tappet which is wound up via the tappet, with a corresponding adjustment of the spring force. As another alternative, only the (first) return spring assigned to the switching tappet can be provided, in case the switching tappet and the tappet are connected.

[0038] More preferably, such a second return spring is provided only in the area of ​​one fork leg or in the area of ​​one tappet extension of the tappet, in order to reduce the switching forces as a whole, so that the second return spring can only directly interact with one tappet, the other tappet extension not being directly acted upon by the return spring.

[0039] The second spring may act against the tappet at the bottom of the end face of the shorter tappet extension in the direction of the initial position of the tappet. The longer tappet extension may be provided with an access opening for the second spring, so that in a corresponding orientation of the tappet the spring acts against the upper edge of the opening in the normal use position of the caster.

[0040] More preferably, only one tappet extension of the tappet is oriented so that it can act on the second return spring, the other tappet extension acting on a lever part of the form-fit locking device. [Brief description of the drawings]

[0041] The invention will be described below with reference to the attached drawings, which show merely exemplary embodiments, in which any part that is described only in connection with one of the exemplary embodiments and which is not replaceable by another part in the other exemplary embodiment due to special features specified therein, is therefore also described as at least possibly present in this further exemplary embodiment. [Figure 1] FIG. 1 shows an exploded perspective view of a caster with a form-fit locking device. [Diagram 2] FIG. 2 shows another exploded perspective view of the caster. [Diagram 3] FIG. 3 shows another exploded perspective view of region III in FIG. [Figure 4] FIG. 4 shows an isolated perspective view of the anti-rotation engagement components of the form-fit fastening device. [Diagram 5] FIG. 5 shows the anti-rotation engagement parts as viewed along arrow V in FIG. [Figure 6] FIG. 6 shows the anti-rotation engagement parts as viewed along arrow V in FIG. [Figure 7] FIG. 7 shows the anti-rotation engagement part as viewed along arrow VII in FIG. [Figure 8] FIG. 8 shows an isolated perspective view of the lever component of the form-fit fastening device. [Figure 9] FIG. 9 shows the lever part as seen along arrow IX in FIG. [Figure 10] FIG. 10 shows the lever component as viewed along arrow X in FIG. [Figure 11] FIG. 11 shows the lever part from another perspective as viewed along the arrow XI in FIG. [Figure 12] FIG. 12 shows another perspective view of the lever component. [Figure 13] FIG. 13 shows a perspective view of the individual mounting components of the form-fit fastening device. [Figure 14] FIG. 14 shows the mounting parts as seen along the arrow XIV in FIG. [Figure 15] FIG. 15 shows the mounting parts as viewed along arrow XV in FIG. [Figure 16] FIG. 16 shows a perspective view of a form-fit fastening device. [Figure 17] FIG. 17 shows the form-fit fastening device as viewed along arrow XVII in FIG. [Figure 18] FIG. 18 shows another perspective view of the form-fit fastening device. [Figure 19] FIG. 19 shows a cross-sectional view taken along line XIX-XIX in FIG. [Figure 20] FIG. 20 shows a cross-sectional view taken along line XX-XX in FIG. [Figure 21] FIG. 21 shows an isolated perspective view of the tappet of the form-fit fastening device. [Figure 22] FIG. 22 shows a cross-sectional view taken along section XXII in FIG. [Figure 23] FIG. 23 shows a cross-sectional view of the caster at section XXIII shown in FIG. 1 with respect to the starting position of the form-fit fixing device. [Figure 24] FIG. 24 shows a cross section through the caster along line XXIV-XXIV in FIG. [Diagram 25] FIG. 25 shows an enlarged view of area XXV in FIG. 23, out of plane along the axis of rotation of the running wheels of the caster. [Figure 26] FIG. 26 shows a cross-sectional view along FIG. 23 for the engaged position of the form-fit fastening device. [Figure 27] FIG. 27 shows an enlarged area XXVII in FIG. 26, out of plane along the axis of rotation. [Figure 28] FIG. 28 shows a view corresponding to FIG. 25, but for the engagement position according to FIG. [Figure 29] FIG. 29 shows a view corresponding to FIG. 28 for a given engagement position. [Diagram 30] FIG. 30 shows an enlarged detail view along FIG. 27 for a given engagement position in FIG. [Diagram 31] FIG. 31 shows a cross section through the caster according to FIG. 24 for a second embodiment of the tappet of the form-fit fastening device. [Diagram 32] FIG. 32 shows an isolated perspective view of the tappet of the embodiment in FIG. [Diagram 33] FIG. 33 shows a cross-sectional view along the section XXXIII in FIG. [Diagram 34] FIG. 34 shows a cross-section along FIG. 31 for a modified arrangement of the tappet of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] A caster 1, which in the illustrated embodiment is designed as a swivel caster type, is first illustrated and described with reference to FIGS.

[0043] The caster 1 basically comprises a running wheel and a fork 3 from which extends a cylindrical mounting pin 4. The mounting pin 4 surrounds a geometric pivot axis x and projects vertically upwards relative to the running wheel 2 when the caster 1 is in normal operating condition.

[0044] The fork 3 may be formed essentially of fork shells 5, 6, as also depicted, each supporting a fork leg 7.

[0045] The fork shells 5, 6 of the fork 3 grip, by their fork legs 7, which preferably substantially coincide in the direction of the rotation axis y, the running wheel 2, which is preferably mounted in a fork hole 8 intended therefor. In the depicted exemplary embodiment, a hollow axle 9, which traverses the center of the running wheel 2 and is preferably supported at each end on a fork leg 7, serves to mount the running wheel 2. As a result, the geometric axis of rotation y of the running wheel 2 is preferably substantially transverse to the pivot axis x and thus lies substantially in a horizontal plane in normal operational use of the caster 1.

[0046] The depicted caster 1 may be placed, for example, on a hospital bed etc. Its attachment may be achieved by means of a mounting pin 4 in the usual way.

[0047] A switching cam 10 arranged pivotably about a drive axis a may additionally be provided on the mounting pin 4 in the region of its upwardly facing free end, whereby the drive axis a may extend substantially perpendicular to the pivot axis x of the castor 1. The switching cam 10 may be provided with a centrally located, non-circular, coupling opening 11 for the rolling-in of the cam 10, which, if applicable, may be hexagonal as in the depicted exemplary embodiment and traversed by a shift lever shaft (not shown) for driving.

[0048] With regard to the representation in FIG. 23, for example a switching tappet 12 may be provided below the switching cam 10, which may activate or release a pivot locking device 13 and / or a form-fit locking device 14.

[0049] In particular, the pivot fixing device 13 and the form-fitting fixing device 14, and additionally the arrangement of the fork shells 5 and 6, may be covered by a housing shell 15, which may further also cover the hub area of ​​the running wheel 2 as depicted in FIG. 1.

[0050] The switching tappet 12 is preferably oriented about the pivot axis x in the mounting pin 4, whereby it is preferably vertically displaceable and fixed against rotation. For this purpose the mounting pin 4 may be provided with a passage 16 with a reduced diameter, which is likewise preferably oriented about the pivot axis x and which, if applicable, can be adapted in cross section to guide the switching tappet 12.

[0051] 23, for example the free end of the changeover tappet 12, which is formed between the opening of the passage 16 and the changeover cam 10, may be connected, for example by threading, to the cam 17. The cam 17 may thereby preferably have a pot-like shape, more preferably a circular cross-section, in which case a region with increased diameter may be formed at the end facing away from the changeover tappet 12 as an annular collar 18. In addition, the cam 17 of the changeover tappet 12 is preferably guided vertically along the pivot axis x in the depicted mounting pin 4.

[0052] Furthermore, the part of the cam 17 with a reduced diameter, in comparison with the annular collar 18, may be surrounded by a first return spring 19, one end of which may be supported under the annular collar 18. The other end of the opposite spring may be supported on the edge of the passage 16. In this way, the switching tappet 12 may be provided such that it is spring-biased in the direction of the switching cam 10 by the first return spring 19. Furthermore, preferably, the end face of the optionally provided annular collar 18 facing the switching cam 10 may have a central shape as the shape of the counter cam 20.

[0053] The switching tappet 12, preferably provided with a counter cam 20, interacts with an opposing control surface 21 of the switching cam 10, which may additionally be provided with control recesses 22 and 23 having different depths in relation to the radial distance from the drive shaft a and arranged one behind the other in the circumferential direction of the switching cam 10.

[0054] The switching cam 10 has a stop limit in its pivoting, when viewed in the circumferential direction of the control surface 21. For this purpose, the locking projection 24 on the mounting pin side can engage, as shown, in a correspondingly provided circumferential groove 25 of the switching cam 10. As can be seen, for example, from the representation in Fig. 23, the circumferential groove 25 is provided substantially opposite the control recesses 22 and 23 with respect to the drive shaft a, and the circumferential groove extends in the circumferential direction over an angular range of approximately 90° in addition.

[0055] The switching tappet 12, viewed in the direction of the running wheel 2, preferably extends towards or into the fork hole 8. The fork hole 8 surrounds a shape of the switching tappet 12 which is preferably circular in cross section and which may be larger in diameter than the upper area of ​​the switching tappet 12. The shape may take on the function of a fixing plate 26 and may be formed in the switching tappet 12 which the fixing plate 26 surrounds transversely to the pivot axis x.

[0056] The fixed plate 26 may have fixing structures 27 on the plate surface facing the switching cam 10. In the so-called fixed caster position, in which the fork 3 with the running wheel 2 can assume only two positions 180 degrees apart from each other with respect to the mounting pin 4, these fixing structures 27 The spring force of the first return spring 19 can press evenly against the bottom surface of the directional fixing part 28. This allows the directional fixing part 28 to be fixed in particular at the fork 3, but also, for example, in the region where the fork 3 is held as a whole on the mounting pin 4 via a bearing 29 and can pivot about the pivot axis x relative to said mounting pin.

[0057] The fixing plate 26 with the fixing structure 27 , which will be described in more detail below, the orientation fixing part 28 and the rotation prevention part 30 are essentially part of the pivot fixing device 13 .

[0058] The fixed caster position can be adopted by rotating the switching cam 10 into the interaction position of the counter cam 20 and the control recess 23, or by other equivalent configurations. Compared to the neutral position shown in FIG. 23, in which the counter cam 20 engages in the additional control recess 22, the fixed caster position can result in a lifting of the cam 17 and the switching tappet 12, and thereby of the fixing plate 26, into the interaction position with the direction fixing part 28, as a result of the spring force applied via the first return spring 19, with reference to the figure.

[0059] The switching tappet 12 may furthermore comprise a rotation prevention projection 31 on the underside of the fixed plate 26 facing away from the fixing structure 27. This rotation prevention projection 31 may for example extend coaxially with the pivot axis x and respectively in the circumferential direction of the fixed plate 26.

[0060] Starting from the fixing plate 26, a preferably circular cylindrical extension 32 with a reduced diameter compared to the fixing plate 26 when viewed in the direction of the running wheel 2 may arise from the switching tappet 12 and may subsequently be inserted for technical guidance into a centrally located through hole of a rotation prevention part 30 arranged around the pivot axis x. The anti-rotation part 30, which is inserted into the fork hole 8 between the running wheel 2 and the fixing plate 26, may be attached non-rotatably by means of the fork 3, like the directional fixing part 28, and may be formed, for example, as a pressed and bent part.

[0061] The anti-rotation piece 30 may have a blocking receiver that matches the shape of the anti-rotation projection 31. The anti-rotation piece 30 is preferably supported on the fork side via a spring element 70 that acts substantially in the direction of the pivot axis x.

[0062] As a result of the interaction of the rotation prevention projection 31 of the fixing plate 26 with the blocking receiver, the castor 1 can be fixed in different pivot positions about the pivot axis x. For this purpose, the switching cam 10 can be pivoted about the drive axis a to a position in which the counter cam 20 contacts the control surface 21 of the switching cam 10 extending radially outward in the circumferential direction, as depicted in FIG. 26. The counter cam 20 together with the switching tappet 12 can be moved downwards in the figure against the force of the first return spring 19. The rotation prevention projection 31 can engage in an associated blocking receiver to prevent the pivoting.

[0063] At the same time, and preferably, a rotational fixation of the running wheel 2 can be achieved in this position. A form-fitting fixing device 14 serves for this purpose.

[0064] Part of the form-fitting fixing device 14 is the fork-shaped tappet 33 shown in a first embodiment in Figures 21 and 22 in separate depictions and used in the caster 1 depicted in Figures 1-30.

[0065] The tappet 33 comprises a crosspiece-like portion of a U-bridge member 34 which extends transversely to the pivot axis x in the region of the fork hole 8 below the extension 32 of the switching tappet 12 in the normal position of installation. Said bridge member 34 carries at each end tappet extensions 35 and 36 which are substantially centrally crossed by the pivot axis x and which, facing away from the switching tappet 12, extend downwards substantially in the direction of the pivot axis x. The tappet extensions 35, 36 and the bridge member 34 give the tappet 33 an overall substantially U-shape, the opening of which is crossed by the running surface of the running wheel 2 so that the tappet extensions 35 and 36 extend on both sides of the running wheel 2.

[0066] In another embodiment, the tappet 33 is linearly guided in the direction of the pivot axis x via the tappet extensions 35 and 36. For this purpose, the tappet extensions 35 and 36 are In the region of the fork shells 5 and 6 there are outwardly directed guide projections 37 which engage in correspondingly arranged guide openings 38 . The guide opening 38 is thereby additionally designed to allow a limited displacement of the tappet 33 as a whole along the pivot axis x at the corresponding engagement of the guide projection 37 .

[0067] The tappet 33 may support a pin 39 on the upper side of the bridge member 34, which pin may engage with a correspondingly positioned and matching opening designed in the anti-rotation part 30, whereby the anti-rotation part 30 is non-rotatably connected to the fork 3 via the tappet 33.

[0068] With reference to a side view of the tappet 33, and in particular the tappet extensions 35, 36, in which the rotation axis y of the running wheel 2 is drawn as a point and the pivot axis x is drawn as a line, on the underside of each free end of the tappet extensions 35, 36 an obliquely extending control surface 40 is formed for acting on a lever part 41 of the form-fit fixing device 14.

[0069] In a preferred embodiment, the movement of the tappet 33, for example directed downwards with reference to the depiction in Fig. 23, is carried out via a winding applied via the switching tappet 12. However, there is preferably no form fit that would allow the tappet 33 and the switching tappet 12 to be pulled back to the neutral position, correspondingly upwards in Fig. 23, as a result of the spring tension via the first return spring 19. Instead, a separate second return spring 42, for example of the type of hairpin spring, is provided for this purpose, which is supported in the fork shells 5, 6 and acts with its spring arm against one of the tappet extensions 35, 36. The second return spring 42 preferably interacts with a tappet extension that, as a result of the arrangement of the tappet 33, is not designed to interact directly with the lever part 41.

[0070] In the first embodiment depicted in Figures 1 to 30, the tappet parts 35 and 36 are designed to be of the same length, the second return spring 42 acts on the underside of the tappet extension 36, and the tappet extension 36 is not arranged to act on the lever part 41 of the form-fit fixing device 14.

[0071] Both return springs 19 and 42 act in substantially the same direction, i.e. upwards towards the changeover cam 10 in the direction of the pivot axis x, as depicted for example in Figure 23. This results in preferably independent spring tensions of the changeover tappet 12 and the tappet 33.

[0072] In addition to the lever part 41, the other basic component of the form-fit locking device 14 is the anti-rotation engagement part 43. This is preferably designed to interact with peripheral teeth 44 provided on the inside of the running wheel.

[0073] The anti-rotation engaging part 43 can be slidably mounted on a mounting part 45 which is fixed to the side of the fork leg. The sliding mobility is provided in particular by a sliding extension 46 which is formed in a T-shape in a cross section transverse to the displacement direction r of the anti-rotation engaging part 43 and which is guided in a sliding receptacle 47 of the mounting part 45 which matches the cross section (see for example Figures 4, 13 and 16).

[0074] The arrangement and orientation of the anti-rotation engaging part 43 may furthermore be selected such that the anti-rotation engaging part 43 is movable along a line b oriented perpendicular to the pivot axis x in a side view according to, for example, Fig. 25. The line b is thereby preferably substantially horizontal in the normal direction of the castor 1 and, with respect to its projection onto a plane in which the axis of rotation y is depicted as a point, for example corresponding to Fig. 25, the displacement direction r of the anti-rotation engaging part 43 forms a right angle α with the movement direction c of the switching tappet 12 and of the tappet 33.

[0075] The anti-rotation engaging part 43 has fixed toothings 48, in two or more of the depicted embodiments four, facing the toothings 44 of the running wheel 2, the spacing and configuration of which match the toothings 44, and are spaced apart from one another in the circumferential direction of the running wheel 2 and spaced apart from the plane of the sliding extension 46 in the direction of the rotation axis y.

[0076] The anti-rotation engagement part 43 additionally supports a plate-shaped support member 49 above the slide extension 46 and vertically spaced therefrom in the mounted and in use state, which, if applicable, lies on and slides across the slide receptacle 47 of the mounting part 45 in the use state, on which a cam-like roll-up projection 50 functions to interact with the lever part 41.

[0077] The mounting part 45 is arranged and held on the inside of one of the fork shells 5, 6. For this purpose the mounting part 45 may be provided with an outwardly facing fixing pin 51 which engages in a retaining manner in a receiving opening 52 arranged at a corresponding position in the fork shell 5.

[0078] The mounting part 45 carries a mounting pin 53 facing inwards and opposite to the fixing pin 51. The lever part 41 is attached to said mounting pin by passing it through a correspondingly arranged pin receiver 54 so as to be pivotable about a pivot axis z oriented parallel to the rotation axis y and perpendicular to the displacement direction r of the anti-rotation engagement part 43.

[0079] The lever part 41 comprises a first drive end 55 for interaction with the roll-up lug 50 of the anti-rotation engagement part 43. Starting from this first drive end 55, in addition, a further second drive end 56 is formed on the other side of the pin receiving part 54 in the form of a shoulder extending generally in the direction of the pivot axis z. This second drive end 56 serves to interact with the tappet 33 and in particular with the control surface 40 of the assigned tappet extension.

[0080] As depicted and described, the lever part 41 and the anti-rotation engagement part 43 are preferably slidably or rotatably supported together on the support part 45. Thereby, more preferably, the form-fitting locking device 14 thus formed is provided solely on one side and assigned to only one fork leg 7, more particularly to only one fork shell 5.

[0081] Furthermore, a stop block 57 is formed integrally with and preferably from the same material as the drive ends 55 and 56 and is shaped as a thickening of the lever part 41 in the extension direction of the pivot axis z and is connected to the area comprising the drive ends 55 and 56.

[0082] Furthermore, two springs are preferably components of the form-fitting locking device 14, both of which are preferably designed as torsion springs. Thus, firstly a first spring 58 is provided which acts between the lever part 41 and the anti-rotation engagement part 43, and then a second spring 59 is provided which acts between the lever part 41 and the mounting part 45 which is fixed to the fork.

[0083] Starting from a central winding member 60 received by the mounting pin 53, one spring leg 61 extends towards the second spring 59 while resting on a support bracket 62 of the mounting part 45 fixed to the fork, while the other spring leg 63 is supported in the area of ​​the first driving end 55 of the lever part 41, so that a corresponding spring load of the lever part 41 is generated in the direction of a starting or initial position allowing free movement of the running wheel 2.

[0084] One spring leg 64 of the first spring 58 is guided in a groove 65 in the region of the stop block 57 of the lever part 41 and, if applicable, is also clamped and held there, so that this spring leg 64 acts on the region of the stop block 57 facing away from the second drive end 55 of the lever part 41, while in this context a winding element 66 is essentially assigned to the second drive end 56, from which the other spring leg 67 arises and forms a lever arm 68 of the lever part 41 and is designed to act on the winding projection 50 of the anti-rotation engagement part 43. The elastic lever arm 68 thus configured acts on the side of the winding projection 50 facing away from the first drive end 55 of the lever part 41.

[0085] Thus, each of the springs 58 and 59 acts on the lever part 41 by one of the spring legs 63, 64 respectively, and furthermore, each of the springs 58 and 59 is preferably and substantially released in the neutral or starting position depicted in particular in Figures 23 to 25, and accordingly does not exert or substantially does not exert a spring force on the lever part 41 and / or the anti-rotation engagement part 43.

[0086] During the, if applicable, stopped-limited rotational displacement of the changeover cam 10 in direction d, the changeover position is reached (see FIG. 26) and, as a result of the downward movement of the changeover tappet 12 in the movement direction c, the counter cam 20 comes into contact with the control surface 21. In addition to the previously mentioned possible pivotal prevention by the fork 3 relative to the mounting pin 4 as a result of the complete locking engagement between the rotation-blocking part 30 and the rotation-blocking projection 31 of the fixing plate 26, an actuation of the second drive end 56 of the lever part 41 takes place additionally via the associated tappet 33 and tappet extension 35 and also via the control surface 40.

[0087] In the course of this downward displacement, the lever part 41 is pivotally displaced about the pivot axis z in the direction of the arrow e (see FIG. 28) and the anti-rotation engagement part 43 is linearly displaced in the displacement direction r via the lever arm 68 of the first spring formed by the spring leg 67 resting on the rolling-in lug 50. Over the course of rolling-in of the anti-rotation engagement part 43, it is preferred that the angle between the spring legs 67 and 64 of the first spring 58 does not change or does not change significantly, at least up to the potential blocking position of the anti-rotation engagement part 43. Instead, the first spring 58 preferably remains substantially detensioned up to the blocking position.

[0088] The anti-rotation engaging part 43 is displaced via a first spring 58, in particular via an elastically designed lever arm 68, in the direction towards a fully locked position with the toothing 44 of the running wheel 2. In this type of fully locked position, the locking toothing 48 of the anti-rotation engaging part 43 engages with the toothing 44 of the running wheel 2, preventing the latter from rotating (see also FIG. 27).

[0089] In the course of a pivotal displacement of the lever part 41 induced in the direction towards the locking position, a tension in the second spring 59 arises, which further acts as a type of return spring for the lever part 41. As mentioned above, only the force of the second spring 59 has to be overcome for the form-fit locking device 14 while adopting the completely locking position with practically no resistance.

[0090] However, during normal use of the castor 1, situations repeatedly occur in which, in the course of attempting to assume a fixed position, the fixed toothing 48 of the rotation-blocking engagement part 43 comes into contact in an obstructive manner against a tooth of the toothing 44 of the running wheel 2 (see the representations in figures 29 and 30). The proposed solution, however, allows a complete displacement of the switching tappet 12 and tappet 13 as well as a complete rotational displacement of the lever part 41, despite the impediment to a complete displacement of the rotation-blocking engagement part 43. Only the spring leg 67, which acts on the roll-up lug 50 of the rotation-blocking engagement part 43 and forms a lever arm 68, is deflected as a result of the blocking, whereby a spring force is stored in the first spring 58, which is designed to be essentially stronger than the second spring 59. This spring force, which forms a force reserve, is preferably stored only in this type of blocking position ("tooth to tooth"). A subsequent rotational displacement of the running wheel 2 by an angle of one or two degrees results in the automatic adoption of the fixed position, while releasing the spring tension of the first spring 58.

[0091] To release this locking position (and, if applicable, the pivot locking), the switching cam 10 is displaced back against the direction of rotation d and accommodates the counter cam 20 in one of the control recesses 22 or 23. The corresponding movement in this case is the upward shifting back of the switching tappet 12 via the first return spring 19 and the upward shifting back of the tappet 33 via the second return spring 42. The lever part 41 can be pivoted back against the direction of rotation e while releasing the spring force of the second spring 59 as a result of the absence of support by the second drive end 56 of the assigned tappet extension 35. The rotation-blocking engagement part 43 is then pushed back linearly in the displacement direction r via the first drive end 55 which is supported on the roll-in lug 50. The fixed toothing 48 leaves the region of the toothing 44, after which the running wheel 2 is again free to rotate about the axis of rotation y. Due to the preferably detensioned arrangement of the first spring 58, in the course of this controlled rearward displacement of the anti-rotation engagement part 43 via the lever part 41, no or no significant forces arise to overcome the set force of the first spring 58 and the force resisting the rearward displacement.

[0092] In particular, the starting position of the anti-rotation engaging part is preferably limited.

[0093] As can be seen from the cross-sectional representation in FIG. 24, the second return spring 42 is arranged on the opposite side of the form-fit fixing device 14 with respect to the central plane of the running wheel, as viewed perpendicular to the rotation axis y, so that this second return spring 42 is preferably designed as a hairpin spring and acts from below with its spring leg on the exposed tappet extension 36.

[0094] In addition, the tappet extensions 35 and 36 of the first embodiment depicted in Figures 1 to 30 are designed with substantially the same length 1 starting from the bridge member 34 (see Figure 22).

[0095] 31 to 34 show another embodiment for a tappet 43, in which the tappet extension 36 is provided with a length l' that is selected to be longer than the length l of the other tappet extension 35. Thus, for example, the tappet extension 36 may have a length l' that corresponds to about 1.2 to about 1.6 times, for example even about 1.4 times, the length l of the shorter tappet extension 35.

[0096] Both tappet extensions 35 and 36 are preferably designed with the above-mentioned control surface 40 on their underside.

[0097] Figure 31 shows the arrangement of the tappet 33 thus configured, which, according to the first embodiment described above, is oriented such that the shorter tappet extension 35 provided with length l is arranged to act on the lever part 41, while the longer tappet extension 36 with length l' is assigned to the second return spring 42. An access opening 69 for interaction with the second return spring 42 is provided in the longer tappet extension 36 for a similar arrangement of the second return spring 42 inside the assigned fork shell 6 .

[0098] This aforementioned arrangement is chosen for a caster 1 with running wheels having a diameter D.

[0099] Due to the arrangement of the tappet 33 rotated 180 degrees relative to the pivot axis x, in comparison with the other components of the form-fit fixing device 14, the caster 1 can also have a running wheel 2 using substantially the same components (except in particular the fork 3 and the running wheel 2), which running wheel 2 has an increased diameter D' than in the embodiment of FIG. 31 (see FIG. 34). This results in the arrangement with the larger diameter running wheel 2 in FIG. 34, in which the longer tappet extension is arranged to act on the lever part 41 and the second return spring 42 contacts the shorter tappet extension 35 on the underside.

[0100] In particular, the lever part 41, the anti-rotation engaging part 43, the mounting part 45, the second return spring 42 and the springs 58 and 59, and additionally the asymmetrically configured tappet 33, can be advantageously used, and more preferably as well, as the basic parts forming the mounting pin 4 and the components for the anti-rotation for the running wheel diameters D and D'.

[0101] The foregoing embodiments serve to describe the invention contained in this application as a whole and independently advance the prior art by at least the following combinations of features, which may also combine two, some, or all of these combinations of features:

[0102] A form-fit fixing device characterized in that a first spring 58 is formed by a lever arm 68 of the lever part 41, whereby as the anti-rotation engagement part 43 is displaced to the engagement position, a second spring 59 can be tensioned to return to a starting position, and the first spring is stronger than the second spring 59.

[0103] A form-fitting fastening device, characterized in that both the first spring 58 and the second spring 59 are substantially unstressed in a starting position.

[0104] A form-fitting fastening device, characterized in that the first spring 58 is designed as a torsion spring.

[0105] A form-fitting fastening device, characterized in that the second spring 59 is designed as a torsion spring.

[0106] A form-fitting fastening device, characterized in that a second spring (59) acts between the lever part (41) and a mounting part (45) fixed to the fork.

[0107] A form-fitting fastening device characterised in that a first spring (58) and a second spring (59) each act at one end of the lever part (41).

[0108] A form-fit fixing device, characterized in that the first spring (58) acts solely between the lever part (41) and the anti-rotation engagement part (43).

[0109] A form-fit fixing device, characterized in that a second spring (59) surrounds the mounting pin (53) of the mounting part (45).

[0110] A form-fitting fastening device, characterized in that the first spring (58) is guided in a groove (65) in the lever part (41).

[0111] A form-fitting fastening device, characterized in that the lever part (41) has two drive ends (55, 56).

[0112] A form-fit fixing device, characterized in that the tappet (33) with tappet extensions (35, 36) of different lengths is formed in the shape of a fork, and only one of the tappet extensions (35, 36) is arranged to act on the lever part (41).

[0113] A form-fitting fastening device, characterized in that the tappet (33) is actuatable by a changeover tappet (12).

[0114] A form-fitting fastening device, characterized in that the tappet 33 interacts with a second return spring 42.

[0115] A form-fitting locking device, characterized in that the switching tappet 12 interacts with a first return spring 19 .

[0116] A form-fit fixing device, characterized in that the second return spring 42 directly interacts only with one of the tappet extensions 35, 36 and that the other tappet extension 35, 36 is not directly actuated by the return spring.

[0117] A form-fitting fixing device characterized in that the longer tappet extension (36) is provided with an access opening (69) for the second return spring (42).

[0118] All disclosed features are essential to the invention (both for themselves and in combination with one another). The disclosure of the present application includes in its entirety the disclosure content of the relevant / attached priority documents (copies and earlier applications), also with a view to incorporating the features of these documents into the claims of the present application. The dependent claims are characterized by an independent, inventive further development of the prior art, even without the features of the claims cited, in particular in order to file a divisional application on the basis of these claims. The invention specified in each claim may additionally have one or more features specified in the preceding description, in particular those given reference signs and / or specified in the explanation of the signs. The present invention also relates in particular to embodiments in which individual ones of the features mentioned in the preceding description are not implemented, insofar as they are obviously unnecessary for the respective purpose of use or can be replaced by other means having the same technical effect. [Explanation of symbols]

[0119] 1 Caster 2 Running wheels 3. Fork 4 Mounting pin 5 Fork Shell 6 Fork Shell 7 Fork Leg 8 Fork Hole 9 hollow shaft 10 Switching Cam 11 Connecting opening 12 Switching tappet 13 Pivoting fixation device 14 Form-fitting retainer 15 Housing Shell 16 Aisle 17 Cam section 18 Circular collar 19 First return spring 20 Opposing Cam 21 Control Surface 22 Control recess 23 Control recess 24 Locking protrusion 25 Circumferential groove 26 Fixing plate 27 Fixed structure 28 Directional Fixing Parts 29 Bearings 30 Anti-rotation parts 31 Anti-rotation protrusion 32 Extension 33 Tappet parts 34 Bridge components 35 Tappet extension 36 Tappet extension 37 Guide protrusion 38 Guide opening 39 pin 40 Control Surface 41 Lever parts 42 Second return spring 43 Anti-rotation engagement part 44 Teeth 45 Installation parts 46 Slide extension 47 Slide Receptacle 48 Fixed tooth section 49 Support member 50 Roll-in protrusion 51 Fixing pin 52 Receptor Aperture 53 Mounting pin 54 Pin Receptacle 55 First drive end 56 Second drive end 57 Contact surface 58 First Spring 59 Second Spring 60 Winding material 61 Spring leg 62 Support bracket 63 Spring leg 64 Spring leg 65 Groove 66 Winding material 67 Spring leg 68 Lever Arm 69 Through hole 70 Spring material a Drive shaft b-line c Movement direction d Rotation direction e Rotation direction l Length l' Length r Extension direction x pivot axis y axis of rotation z pivot axis D diameter D' diameter α angle

Claims

1. A form-fitting fixing device (14) for a caster (1) with a running wheel (2), a fork (3) and a rotation-preventing engaging part (43), comprising: The running wheel (2) of the caster (1) can be prevented from rotating about the geometric running wheel axis (y) via the rotation prevention engagement part (43), Furthermore, in the form-fit locking device (14), a first spring (58) acts on the rotation-preventing engaging part (43) for displacement of the rotation-preventing engaging part (43) from a starting position to an engaged position, said first spring (58) being mounted on a pivotable lever element (41); the first spring (58) forms a lever arm (68) which is part of the first spring and which itself has a corresponding elasticity; With the displacement of the rotation prevention engaging part (43) to the engaging position, a second spring (59) attached to the lever part (41) can be tensioned to return to the starting position; and A form-fitting fastening device characterized in that said first spring (58) is stronger than said second spring (59).

2. 2. A form-fit locking device according to claim 1, characterized in that both the first spring (58) and the second spring (5) are substantially de-tensioned in the starting position.

3. 3. Form-fitting fastening device according to claim 1 or 2, characterized in that the first spring (58) is designed as a torsion spring.

4. 2. Form-fitting fastening device according to claim 1, characterized in that the second spring (59) is designed as a torsion spring.

5. 2. A form-fitting locking device according to claim 1, characterized in that the second spring (59) acts between the lever part (41) and a mounting part (45) fixed to the fork.

6. 2. A form-fit fixing device according to claim 1, characterized in that the first spring (58) and the second spring (59) each act on one end of the lever element (41).

7. 2. A form-fit locking device according to claim 1, characterized in that the first spring (58) acts solely between the lever part (41) and the anti-rotation engagement part (43).

8. 2. A form-fit fastening device according to claim 1, characterized in that the second spring (59) surrounds the mounting pin (53) of the mounting part (41).

9. 2. Form-fitting locking device according to claim 1, characterized in that the first spring (58) is guided in a groove (65) in the lever part (41).

10. 2. Form-fit fixing device according to claim 1, characterized in that the lever element (41) comprises two drive ends (55, 56).

11. A form-fitting fixing device (14) for a caster (1) comprising a running wheel (2), a fork (3) and a rotation-preventing engagement part (43), comprising: The running wheel (2) of the caster (1) can be prevented from rotating about the geometric running wheel axis (y) via the rotation prevention engagement part (43), Furthermore, the rotation preventing engaging part (43) can be actuated via a lever part (41) for displacement of the rotation preventing engaging part (43) from a start position to an engaging position and / or from an engaging position to a start position, Furthermore, in the form-fit locking device (14), the lever element is actuatable by a tappet (33), the tappet (33) with tappet extensions (35, 36) of different lengths is formed in the shape of a fork, and only one of the tappet extensions (35, 36) is arranged to act on the lever element (41); In the normal orientation of the caster (1), the tappet extensions (35, 36) extend substantially vertically; and A form-fit fixing device, characterized in that the tappet extensions (35, 36) extend along and on either side of the mounting pin axis of the mounting pin surrounding the geometric pivot axis.

12. 12. Form-fit fixing device according to claim 11, characterized in that the tappet (33) is actuatable by a changeover tappet (12).

13. 13. Form-fitting fixing device according to claim 11 or 12, characterized in that the tappet (33) interacts with a second return spring (42).

14. 13. Form-fitting locking device according to claim 12, characterized in that the switching tappet (12) interacts with a first return spring (19).

15. 14. A form-fit fixing device according to claim 13, characterized in that the second return spring (42) interacts directly with only one of the tappet extensions (35, 36), and the other tappet extension (35, 36) is not directly actuated by the return spring.

16. 16. A form-fit fixing device according to claim 15, characterized in that the longer tappet extension (36) comprises an access opening (69) for the second return spring (42).

17. 12. A form-fit fastening device according to claim 11, characterized in that the mounting pin axis passes through substantially the centre of the U-shaped crossbar of the tappet (33).

Images