STEM FOR A BICYCLE WITH ELASTOMER DAMPING

Abstract

A sprung stem for bicycles, in particular for racing bicycles and gravel bikes, for the sprung connection between the handlebar and the head tube and/or the steerer tube with improved damping is proposed, wherein a coupling apparatus for mechanical coupling of the connecting parts is provided, which coupling apparatus comprises at least one elastomer body which is mounted in such a way that it is deformed during pivoting of the static fastening device with respect to the handlebar holder, in order thus to absorb force and to damp the relative movement between the handlebar and the head tube.

Claims

1. A sprung stem for bicycles for the sprung connection between the handlebar and the head tube and/or the steerer tube, comprising: a static fastening device for fastening the stem to the head tube and/or the steerer tube, a handlebar holder for connecting the stem to the handlebar, a suspension apparatus for suspending the handlebar and for mechanical coupling between the static fastening device and the handlebar holder, wherein the suspension apparatus is split at least in two and comprises two connecting parts which both in each case connect the fastening apparatus and the handlebar holder, wherein the suspension apparatus is mounted via two pivot pins on the static fastening device and via two pivot pins on the handlebar holder, wherein the connecting parts are connected rotatably firstly in each case via one of the pivot pins to the fastening apparatus and secondly via another one of the pivot pins to the handlebar holder, with the result that the spacing between the two pivot pins which are connected to one another by way of the same connecting part is constant, and/or the side lengths of a parallelogram which is formed are constant, wherein the pivot pins run parallel to one another and are arranged in such a way that the pivot pins penetrate a plane perpendicularly with respect to the pivot pins in such a way that the penetration points configure the corner points of the parallelogram, and wherein a coupling apparatus is provided for mechanical coupling of the connecting parts, which coupling apparatus comprises at least one elastomer body which is mounted in such a way that it is deformed during pivoting of the static fastening device with respect to the handlebar holder, in order thus to absorb force and to damp the relative movement between the handlebar and the head tube.

2. The sprung stem according to claim 1, wherein the connecting parts: are in each case of rigid configuration, and/or are configured in each case as shells, and the at least one elastomer body is mounted at least partially therein, wherein the shells of two of the connecting parts are oriented so as to in each case face one another, with the result that the elastomer body or the elastomer bodies is/are mounted between the connecting parts in the shells, preferably without an integrally joined connection between elastomer body and the respective shell, wherein the shells in each case have a bottom and a wall, wherein the elastomer body bears with an end side against the bottom, and wherein the wall laterally covers the elastomer body which is mounted therein, in order to prevent lateral slipping of the elastomer body.

3. The sprung stem according to claim 1, wherein the coupling apparatus has at least two elastomer bodies which are connected in series in a connecting line between the fastening device and the handlebar holder, wherein a spacer element is arranged between the at least two elastomer bodies which are connected in series, in order to set the spacing and/or the coupling and/or the play between the at least two elastomer bodies which are connected in series, wherein the spacer element is of wedge-shaped configuration and being arranged in such a way that it performs the setting operation by way of displacement.

4. The sprung stem according to claim 3, wherein the spacer element comprises two wedge-shaped spacer elements, the points of which point toward one another, and which spacer elements are connected to one another by way of a setting screw, with the result that the spacing between the spacer elements can be set by way of rotation of the setting screw.

5. The sprung stem according to claim 1, wherein two elastomer bodies which are connected in series are arranged along each of the connecting parts.

6. The sprung stem according to claim 1, wherein in each case two elastomer bodies are arranged next to one another transversely with respect to the connecting parts in each case two elastomer bodies are connected in parallel and two elastomer bodies are connected in series.

7. The sprung stem according to claim 1, wherein a normal position is provided, in which the coupling apparatus assumes a position, without an external force acting on it, and/or in that the coupling apparatus is configured to be deflected in the two rotational directions about the pivot pins, in order to provide a positive and a negative spring travel.

8. The sprung stem according to claim 1, further comprising a stop element is on the fastening device and/or on the handlebar holder, against which stop element the connecting parts can bear in each case during rotation about the pivot pin, and a further continuation of the rotation is thus prevented, wherein the at least one stop element: is configured as an elastomer, and/or is attached between the two pivot pins to the fastening device and/or between the two pivot pins to the handlebar holder.

9. The sprung stem according to claim 1, wherein the at least one elastomer body has a change in cross section in a cross section along a plane which runs parallel to the pivot pins, and/or parallel to the spacer elements, wherein: there is the greatest contact area between the respective elastomer body and the spacer element in the center of the respective elastomer body, and/or the contact area between the respective elastomer body and the spacer element increases toward the center of the respective elastomer body disproportionately with a displacement of the spacer element toward the center of the elastomer body, and/or the at least one elastomer body has an X-shape and/or the shape of an hourglass and/or the shape of two wedges, the tips of which face one another, in cross section along a plane which runs parallel to the pivot pins.

10. The sprung stem according to claim 1, wherein the elastomer body and/or a single one of the elastomer bodies is penetrated by the respective connecting lines between the fastening device and the handlebar holder, which connecting lines perpendicularly intersect the respective two pivot pins which lie opposite one another, wherein the elastomer body is configured and arranged in such a way that it is smaller in the direction of the connecting lines between the pivot pins which lie opposite one another than with regard to its extent between the two shells and/or connecting parts, with the result that the elastomer body is rather sheared than compressed.

11. The sprung stem according to claim 1, wherein the coupling apparatus has precisely one elastomer body for mechanical coupling of the connecting parts.

12. The sprung stem according to claim 1, wherein the at least one elastomer body is configured as a closed ring.

13. The sprung stem according to claim 1, wherein the elastomer body: is of axially symmetrical configuration with regard to an axis of symmetry which runs parallel to the pivot pins, and/or the elastomer body has a stepped shape on its outer shell, with the result that two steps which are arranged diagonally with respect to one another in relation to the axis of symmetry are provided, wherein the higher step is situated in each case in the region of the respective other connecting part, and wherein the respective step which is mounted further to the outside from the center of the elastomer body faces in one case the fastening device and in one case the handlebar holder, wherein the elastomer body is configured with regard to its axial symmetry and/or its stepped shape to orient the parallelogram which is formed in such a way that its interior angles in each case differ from 90°.

14. The sprung stem according to claim 1, wherein the elastomer body has, along its axis of symmetry, a recess which penetrates the elastomer body for receiving mounting shafts and/or for introducing an element for setting the spring hardness, which recess is preferably of slot-shaped configuration.

15. The sprung stem according to claim 1, wherein the elastomer body and/or the recess are/is penetrated by one or more mounting shafts which runs/run parallel to the axis of symmetry, wherein: the mounting shafts run in one plane, and/or one of the mounting shafts lies on the axis of symmetry, and/or one of the mounting shafts comprises a body which is configured as a spring stiffness pin and is mounted such that it can be adjusted in a linear manner, in order for it to be possible for it to be introduced into the elastomer body and moved out again, such that, as a result, the stiffness of the coupling apparatus and/or the sprung stem can be set, and/or the mounting shafts are connected to one another via at least one connecting web, and/or the spring stiffness pin has a thread which is in engagement with the thread of an adjusting spindle, in order, as a result, to implement a linear movement in the direction of the elastomer body or away from the elastomer body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Exemplary embodiments of the present invention are shown in the drawings and will be described in greater detail in the following text with the specification of further details and advantages.

[0046] FIG. 1 shows a diagrammatic illustration of a stem in accordance with the present invention, the upper connecting part being hidden;

[0047] FIG. 2 shows an illustration of the complete stem from FIG. 1;

[0048] FIG. 3 shows a sectional illustration along the longitudinal extent of the stem from FIG. 1; and

[0049] FIG. 4 shows a diagrammatic illustration of the coupling apparatus with elastomer bodies and spacer elements (exploded illustration); and, furthermore:

[0050] FIG. 5 shows a diagrammatic illustration of a part of the coupling apparatus for one exemplary embodiment with only one contiguous elastomer body;

[0051] FIGS. 6, 7 show the positioning of the spring stiffness pin in the case of the setting of the degree of hardness of the coupling apparatus; and

[0052] FIG. 8 shows a diagrammatic illustration of a stem with a coupling apparatus according to FIG. 5 (section).

DETAILED DESCRIPTION OF THE INVENTION

[0053] FIG. 1 shows a sprung stem 1 with a static fastening device 2 which can engage around the steerer tube or the head tube, a handlebar holder 3 which in turn can engage around the handlebar, and with a suspension apparatus 4 which connects the fastening device 2 to the handlebar holder 3. The suspension apparatus 4 comprises two connecting parts 5, 6 (cf. also FIG. 2). FIG. 1 shows only the lower connecting part 6. Two pivot pins 7, 8 are situated on the fastening device to, just as two pivot pins 9, 10 are arranged on the handlebar holder 3. Each connecting part 5, 6 is mounted pivotably via the pivot pins 7, 9 and 8, 10 on the one side on the fastening device 2 and on the other side on the handlebar holder. The connecting lines of the pivot pins 7 to the pivot pin 9 to the pivot pin 10 to the pivot pin 8 and back again to the pivot pins 7 form a parallelogram.

[0054] Shells 11, 12 are machined in the connecting parts. The shells 11, 12 are arranged with their openings toward one another. Each shall 11 and 12 receives in each case two elastomer bodies 13, 14 and 15, 16, respectively. Therefore, the two elastomer bodies 13, 14 and 15, 16 are in each case arranged in series, whereas the elastomer bodies 13, 15 and 14, 16 are arranged parallel to one another.

[0055] A setting screw 17 is provided transversely through the center of this foursome arrangement of elastomer bodies 13, 14, 15, 16, on the thread axis of which setting screw 17 wedge-shaped spacer elements 18, 19 are screwed in or mounted. By way of rotation of the setting screw 17, the wedges 18, 19 are pushed closer together or moved further apart from one another. In FIG. 1, the spacer elements 18, 19 are continued below the setting screw 17, that is to say spacer elements 18, 19 are not only arranged between the elastomer bodies 13, 14 but also between the elastomer bodies 15, 16. They are analogously wedge-shaped. The gap 20 is reduced in size when the wedges (spacer elements) 18, 19 are pushed together.

[0056] The elastomer bodies 21 are additionally held by way of a fixing means 21.

[0057] As viewed along a connecting axis between the static fastening apparatus 2 and the handlebar holder 3, the elastomer bodies 13, 14, 15, 16 have approximately an X-shape or, more precisely, the shape of an hourglass, that is to say recesses 22, 23 are present in the lateral regions.

[0058] If the front wheel experiences a jolt, for instance in the case of off-road riding, this jolt is transmitted via the fork or the head tube to the fastening device and via the suspension apparatus for toward the handlebar holder 3. On account of the inertia of the handlebar and the rider supported thereon, the suspension apparatus 4 is pivoted, and the handlebar moves relative to the head tube. On account of the parallelogram construction of the stem, however, the handlebar is not rotated about its own longitudinal axis, and the hands of the rider are not rotated, but rather remain in their orientation.

[0059] By virtue of the fact that the elastomer bodies 13, 14, 15, 16 are received substantially without play in the shells 11, 12, they are deformed in the case of pivoting of the connecting parts 5, 6. The material can yield partially into the gaps 20, 22, 23. The closer the spacer wedges 18, 19 are moved together, the smaller the gap 20 becomes. Moreover, the elastomer bodies 13, 14 are compressed on account of the wedge shape. The mechanical resistance becomes greater during the suspension movement.

[0060] Stop elements 24 in the form of elastomers are introduced centrally in each case between the pivot pins 7, 8 and between the pivot pins 9, 10. During pivoting, the connecting parts 5, 6 can come into contact there if the deflection becomes too great (cf. FIG. 3).

[0061] FIG. 4 shows the elastomer bodies 13, 14, 15, 16 which, as viewed laterally, have a type of “X-shape” or the shape of an “hourglass”, in order to set the mechanical resistance during the deformation. The resistance is increased disproportionately by way of the shape which tapers toward the center, the closer the spacer elements 18, 19 approach the center of the elastomer bodies 13, 14, 15, 16, since the gaps 22, 23 are reduced in size greatly here toward the center and more elastomer body has to be deformed. By way of rotation of the setting screw 17, the spacer elements 18, 19 which are of wing-like configuration are displaced with their wedge-shaped wings along the setting screw and are thus moved closer to the center of the elastomer bodies 13, 14, 15, 16 or further away from the center of 13, 14, 15, 16. The closer to the center they are situated, the higher the mechanical resistance, since the elastomer bodies 13, 14, 15, 16 are already pre-compressed and the space for yielding of the elastomer bodies 13, 14, 15, 16 likewise shrinks. The elastomer bodies 13, 14, 15, 16 and the spacer elements 18, 19 which are mounted via the setting screw 17 form the essential parts of the coupling apparatus K.

[0062] FIG. 5 diagrammatically shows the construction of a part of the coupling apparatus K with a single, contiguous elastomer body 13 with a closed ring shape. The elastomer body 13 is axially symmetrical in relation to the axis of symmetry S which is shown. The outer shell of the elastomer body 13 has two steps 30, 31 which lie diagonally opposite one another in relation to the axis of symmetry S. In a manner which corresponds to its annular structure, the elastomer body 13 has a through bore or recess 32 which passes through the body and is of slot-shaped configuration, that is to say extends considerably further in the longitudinal direction than transversely with respect thereto. The orientation of the slot 32 approximately follows the course direction of the steps 30, 31. This step-like construction of the elastomer body 13 ensures that the center of the fastening device 2 and the handlebar holder 3 are displaced with respect to one another. The height of the handlebar is displaced (in this regard, see also FIG. 8).

[0063] The spring stiffness pin 33 which is arranged on the middle mounting shaft which coincides with the axis of symmetry S has a substantially oval cross section. The recess in the elastomer body 13, through which the middle mounting shaft runs, is slot-shaped and, as a result, is configured such that the spring stiffness pin 33 bears against the inner walls of the recess 32, and the further it is introduced into the recess 32, the more its deformation capability decreases. As a consequence, the hardness of the coupling apparatus K can be set by the depth to which the spring stiffness pin 33 is introduced into the elastomer body 13, that is to say by how much the spring stiffness pin 33 co-defines the deformation properties of the elastomer body 13. In order for it to be possible for the spring stiffness pin 33 to be displaced along the middle longitudinal axis or axis of symmetry S, it is mounted on an adjusting spindle 34. The adjusting spindle 34 has an external thread which engages into an internal thread of the spring stiffness pin 33. Since the spring stiffness pin 33 is mounted at least partially in the slot-shaped recess 32 of the elastomer body 13, it is sufficient to prevent a rotation of the spring stiffness pin 33, that is to say the pin 33 can be moved in a linear manner by way of the adjusting spindle 34 as a result of this non-rotational mounting, that is to say can be introduced to a greater or lesser extent into the elastomer body 13. When it is introduced completely into the elastomer body 13, the spring stiffness pin 33 forms a hard core which makes the overall structure of the coupling apparatus K seem harder with respect to deformations and/or shear movements.

[0064] The adjusting spindle 34 and the mounting shafts 35, 36 are held via the two connecting webs 37, 38 in a defined position with respect to the elastomer body 13.

[0065] As can be seen in FIG. 5, the shafts 35, 36 are surrounded each case by a spacer sleeve 39, 40, in order to obtain improved retention in the elastomer body 13 as a result of the increased diameters. In order to mount the shafts 35, 36 and the adjusting spindle 34 rotatably on the web 37, 38, clips 41 are provided. In addition, washers 42 can be used for improved mounting. In order that the adjusting spindle 34 also remains in this set position during the adjustment, a self-locking means is necessary. To this end, an O-ring 43 (sealing ring) bears against the adjusting spindle 34.

[0066] FIGS. 6 and 7 in turn show a side view of this part of the coupling apparatus K, namely the elastomer body 13 which is penetrated by the mounting shafts 35, 36. An adjusting spindle 34 is arranged in the region of the middle mounting axis, on the thread of which adjusting spindle 34 the spring stiffness pin 33 is seated. The spring stiffness pin 33 dips at least partially into the elastomer body 13, more precisely into the recess 32 in the elastomer body 13. The mounting shafts 35, 36 are arranged via two connecting webs 37, 38, in each case one in front of and one behind the elastomer body 13. The adjusting spindle 34 which is also held by one of the connecting webs 37 is situated on the middle mounting axis or the axis of symmetry S. In the case of hard setting (FIG. 6), the spring stiffness pin 33 dips further into the elastomer body 13 than in the case of soft setting (FIG. 7).

[0067] FIG. 8 shows a section through a stem with a coupling apparatus or an elastomer body 13 in accordance with the exemplary embodiment according to FIG. 5. The fastening apparatus 2 engages around the head tube or the fork. As a result of the stepped shape of the elastomer body 13, the coupling apparatus K is tilted slightly with respect to a horizontally running line in FIG. 8, with the result that, in contrast, the handlebar holder 13 is offset upward somewhat.

LIST OF REFERENCE SIGNS

[0068] 1 Stem [0069] 2 Static fastening device [0070] 3 Handlebar holder [0071] 4 Suspension apparatus [0072] 5 Connecting part [0073] 6 Connecting part [0074] 7 Pivot pin [0075] 8 Pivot pin [0076] 9 Pivot pin [0077] 10 Pivot pin [0078] 11 Shell [0079] 12 Shell [0080] 13 Elastomer body [0081] 14 Elastomer body [0082] 15 Elastomer body [0083] 16 Elastomer body [0084] 17 Setting screw [0085] 18 Spacer element [0086] 19 Spacer element [0087] 20 Gap [0088] 22 Gap [0089] 23 Gap [0090] 24 Stop element [0091] 30 Step [0092] 31 Step [0093] 32 Recess [0094] 33 Spring stiffness pin [0095] 34 Adjusting spindle [0096] 35 Mounting shaft [0097] 36 Mounting shaft [0098] 37 Connecting shaft [0099] 38 Connecting shaft [0100] 39 Sleeve [0101] 40 Sleeve [0102] 41 Clip [0103] 42 Washer [0104] 43 O-ring (sealing ring) [0105] K Coupling apparatus [0106] S Axis of symmetry