Handlebar stem for a bicycle and bicycle

Abstract

Handlebar stem (38) for a bicycle (10), with a length-adjustable, telescopically designed fastening device (40) for attaching a handlebar (34) to a front fork (30), wherein the fastening device (40) is designed such that the handlebar (34) is adjustable between different heights, and wherein the fastening device (40) has an outer tube (52) and an inner tube (50) connected telescopically to the outer tube (52) and connected to the outer tube (52) in a manner that prevents rotation about a longitudinal axis, wherein the fastening device (40) has a hydraulic damper (70) which has a piston (77) fixedly connected to the inner tube (50) and two fluid chambers (72, 74) arranged inside the outer tube (52) and separated from each other by the piston (77), wherein characterized by the fact that the piston (77) of the damper (70) has a first hydraulic passage opening (82) designed as an inlet opening (83) and a second hydraulic passage opening (84) designed as an extension opening (85), through which the two fluid chambers (72, 74) can be fluidically connected to each other, a first check valve (86) is arranged at the inlet opening (83) and a second check valve (88) is arranged at the outlet opening (85), the two check valves (86, 88) are designed in such a way as to be opposite to each other that the first check valve (86) only allows a hydraulic mass flow between the two fluid chambers (72, 74) during a retraction movement of the inner tube (50) and the second check valve (88) only allows a hydraulic mass flow between the two fluid chambers (72, 74) during an extension movement of the inner tube (50).

Description

[0001] The invention relates to a handlebar stem for a bicycle according to the preamble of claim 1. Furthermore, the invention relates to a bicycle.

[0002] A height-adjustable handlebar arrangement for a bicycle is known, for example, from EP 3 450 294 B1. In this arrangement, the bicycle has a handlebar stem with a telescopic mounting device comprising an inner tube and an outer tube. The inner tube is longitudinally displaceable relative to the outer tube, with the handlebars being attached to the inner tube and the outer tube being connected to a front fork. The height of the handlebars, and thus the fixation of the inner tube relative to the outer tube, is achieved by a clamping device.

[0003] The problem with this type of handlebar stem design is that if the clamping device is defective or unintentionally released, there is a risk that the inner tube will unexpectedly plunge into the outer tube while riding, causing loss of control over the bicycle and potentially resulting in an accident with a high probability of injury to the rider.

[0004] KR 10 2017 0 111 669 A1 discloses a handlebar stem for a bicycle according to the preamble of claim 1.

[0005] The object of the present invention is to provide a handlebar stem with adjustable handlebar height, thereby reducing the risk of injury to the rider due to a defective or incorrectly adjusted mounting device. Furthermore, a bicycle equipped with such a handlebar stem is to be provided.

[0006] The problem is solved by a handlebar stem for a bicycle according to claim 1 and by a bicycle according to claim 7.

[0007] Because the fastening device incorporates a hydraulic damper, which has a piston rigidly connected to the inner tube and two fluid chambers arranged within the outer tube and separated from each other by the piston, and the piston has at least one hydraulic passage through which the two fluid chambers can be fluidically connected, a sudden immersion of the inner tube into the outer tube can be reliably prevented. A jerky immersion of the inner tube is prevented by the fact that, during the insertion of the inner tube into the outer tube, a hydraulic fluid, in particular oil, must flow through a relatively small opening on the piston between the two fluid chambers. Due to the incompressibility of the hydraulic fluid and the relatively small opening, the insertion process, and thus the immersion, can only occur very slowly.In other words, the insertion speed of the inner tube depends on the speed of the hydraulic fluid as it flows through the opening.

[0008] In this way, handlebar height adjustment can be provided, and even without mechanical fixation of the inner tube to the outer tube, a sudden retraction of the inner tube and thus an unexpected lowering of the handlebar is reliably prevented. The two fluid chambers form a closed system. In addition to the hydraulic fluid, a gas, in particular air, is present in the fluid chambers, which is compressed when the hydraulic fluid flows through the corresponding fluid chamber.

[0009] The damper has a first hydraulic passage opening, designed as an inlet, and a second hydraulic passage opening, designed as an extension opening. A first check valve is arranged at the inlet opening and a second check valve at the extension opening. The two check valves are configured in opposite directions such that the first check valve allows hydraulic mass flow between the two fluid chambers only during an inlet movement of the inner tube, and the second check valve allows hydraulic mass flow between the two fluid chambers only during an extension movement of the inner tube. This allows the damping of the inlet and extension processes to be carried out independently of each other.

[0010] Preferably, a spring element is arranged longitudinally between the inner tube and the outer tube, the spring element being designed such that it loads the inner tube in the extension direction. The spring element is designed such that the inner tube is loaded into a maximally extended position. When the handlebars are to be moved into a lowered position, the rider can use their body weight to move the inner tube into the outer tube against the spring force of the spring element, whereby during the desired retraction movement, the hydraulic fluid flows from a lower fluid chamber to an upper fluid chamber through the opening on the piston. When the handlebars are released, the inner tube would extend due to the spring force until it abuts a stop provided on the outer tube.This allows for a simple, space-saving and cost-effective way to provide height adjustment and prevents the inner tube from retracting unexpectedly, which poses a high risk of injury to the driver.

[0011] In a preferred embodiment, the inner and outer tubes are connected to each other in a rotationally secure manner via a tongue-and-groove connection. For example, the inner tube has a projection, i.e., a spring, on an outer circumferential surface, and the outer tube has a groove extending longitudinally over the entire adjustment range of the inner tube. The projection engages in the groove and slides along it during an adjustment operation of the inner tube. This provides a simple and reliable method of preventing rotation.

[0012] Preferably, the fastening device comprises a clamping device arranged on an outer circumferential surface of the outer tube, wherein the inner tube can be fixed in different positions by means of a deformation of the outer tube caused by the clamping device. In a preferred embodiment, the clamping device comprises a slotted clamping ring and an actuating lever, wherein the actuating lever is connected via an eccentric section to one free end of the slotted clamping ring and to a bolt connected to the other free end of the slotted clamping ring. This allows the inner tube to be fixed in different positions in a simple manner.

[0013] In a preferred embodiment, the inlet opening has a smaller diameter than the outlet opening. This reliably prevents the inner tube from retracting abruptly and also accelerates its extension.

[0014] The advantages of the procedure are described in the preceding paragraphs.

[0015] This design of the handlebar stem allows for height adjustment of the handlebars, while reliably preventing the inner tube from retracting unexpectedly and thus the handlebars from lowering even if the inner tube is not mechanically fixed to the outer tube. This increases riding safety.

[0016] An embodiment of the invention is explained in more detail with reference to the drawings. Fig. Figure 1 schematically shows a bicycle in side view, and Fig. Figure 2 shows a handlebar stem for a bicycle. Fig. 1 in cross-section.

[0017] Fig. Figure 1 shows a bicycle 10, which has a frame 12. The frame 12 includes, among other things, a seat tube 14 for receiving a seat post 18 supporting a saddle 16, a rear triangle 20 for receiving a rear wheel 22, a top tube 24, a down tube 26, and a head tube 28 for receiving a front fork 30. The front fork 30 is rotatably mounted on the head tube 28 about a longitudinal axis and serves to attach a front wheel 32.

[0018] A handlebar 34 is provided for steering the bicycle 10, which is connected to the front fork 30 in a rotationally fixed manner via a handlebar stem 38. Such a handlebar stem 38 is in Fig. 2 shown.

[0019] The handlebar stem 38 comprises a mounting device 40, which includes a handlebar mounting element 44 and a fork mounting device 46. The handlebar mounting element 44 is rigidly connected to the handlebar 34, the handlebar 34 being attached to the handlebar mounting element 44 in particular via a clamping connection. The handlebar mounting element 44 is also coupled to the fork mounting device 46.

[0020] The fork mounting device 46 comprises an inner tube 50 and an outer tube 52, wherein the inner tube 50 is inserted into the outer tube 52 and is rigidly connected to the handlebar mounting element 44 at a longitudinal end facing away from the outer tube 52. The inner tube 50 is connected to the outer tube 52 in a rotationally fixed manner via a spring-groove connection 56, wherein a radial projection 58, i.e., the spring of the spring-groove connection, is formed on an outer circumferential surface of a section of the inner tube 50 that is immersed in the outer tube 52, and this projection engages in a groove 59 extending longitudinally in the outer tube 52. This ensures that the inner tube 50 is rotationally fixed to the outer tube 52 in different positions relative to the outer tube 52. The outer tube 52 is rigidly connected to the front fork 30. Alternatively, the outer tube 52 can also be manufactured as a single piece with the front fork 30.

[0021] By designing the fastening device 40 in this way, the inner tube 50 can be moved telescopically relative to the outer tube 52, whereby the height of the handlebar 34 can be adjusted by moving the inner tube 50 relative to the outer tube 52. After the desired height of the handlebar 34 has been set, a clamping device 60 prevents any further movement of the inner tube 50 relative to the outer tube 52, thus fixing the handlebar 34 at the desired height. The clamping device 60 comprises a slotted clamping ring 62, which is arranged on an outer circumferential surface of the outer tube 52, an actuating lever 64 connected to one free end of the slotted clamping ring 62, and a bolt 66 connected to the other end of the slotted clamping ring 62. The actuating lever 64 is connected to the bolt 66 and has an eccentric section, whereby an adjustment, i.e.,The twisting of the actuating lever 64 shortens the resulting length of the bolt 66 and the actuating lever 64 essentially in the tangential direction of the clamping ring 62, thereby tightening the clamping ring 62. The outer tube 52 could also be weakened, for example by a slot, to prevent deformation of the outer tube 52 and ensure clamping between the outer tube 52 and the inner tube 50.

[0022] The fastening device 40 also includes a hydraulic damper 70, which serves to prevent the inner tube 50 from being jerked into the outer tube 52 even when the clamping device 60 is open, thus preventing the bicycle 10 from becoming difficult to control while riding. This significantly reduces the risk of injury to the rider.

[0023] The hydraulic damper 70 comprises a first fluid chamber 72 and a second fluid chamber 74. The first fluid chamber 72 is radially bounded by an inner circumferential surface of the inner tube 50 and axially bounded by two plate-like closure elements 75 and 76. A first closure element 76 is arranged inside the inner tube 50 and is attached to the inner circumferential surface of the inner tube 50, in particular by a press fit. The second closure element 75 is arranged on an end face of the inner tube 50 that is immersed in the outer tube 52 and is also connected to the inner tube 50 by a press fit. The second fluid chamber 74 is radially bounded by the outer tube 52 and axially bounded by the inner tube 50, the second closure element 75, and a third closure element 78, wherein the third closure element 78 is pressed into the outer tube 52 and is thus fixedly arranged on an inner circumferential surface of the outer tube 52.

[0024] The two fluid chambers 72, 74 are fluidically connected to each other via two hydraulic passage openings, 82, 84, i.e., an inlet opening 83 and an outlet opening 85, so that oil flows between the two fluid chambers 72, 74 via the inlet or outlet opening 83, 85 during height adjustment of the handlebar 34, i.e., during retraction and extension of the inner tube 50 into and out of the outer tube 52. The inlet opening 83 and the outlet opening 85 are formed on the second closure element 75, since the second closure element 75 separates the two fluid chambers 72, 74 from each other and thus serves as the piston 77 of the hydraulic damper 70. The inlet opening 83 and the outlet opening 85 are each closed by a check valve 86, 88. The first check valve 86, located at the inlet opening 83, is designed and arranged such that the check valve 86, when the inner tube 50 is inserted into the outer tube 52, i.e.When the inner tube 50 is inserted into the outer tube 52, and thus when the height of the handlebar 34 is reduced, the insertion opening 83 is opened, and when the inner tube 50 is extended out of the outer tube 52, the insertion opening 83 is closed. The second check valve 88, located at the extension opening 85, is designed and positioned such that when the inner tube 50 extends out of the outer tube 52, i.e., when the height of the handlebar 34 increases, the second check valve 88 opens the extension opening 85, and when the inner tube 50 retracts into the outer tube 52, the insertion opening 83 is closed. The insertion opening 83 has a diameter d1, and the extension opening 85 has a diameter d2, with the diameter d1 of the insertion opening 83 being smaller than the diameter d2 of the extension opening 85.The relatively small diameter d1 of the inlet opening 83 reliably prevents the inner tube 50 from being drawn into the outer tube 52 abruptly, as the incompressible oil can only flow slowly through the small inlet opening 83. The larger extension opening 85 allows the extension of the inner tube 50 to be accelerated, as the oil exchange between the fluid chambers 72 and 74 can occur more quickly through the larger extension opening 85.

[0025] A spring element 80 is arranged in the second fluid chamber 74. This spring element is supported by the third locking element 78 and axially loads the inner tube in the extension direction. Thus, when the clamping device 60 is released, the spring element 80 loads the inner tube 50 in such a way that the inner tube 50 extends out of the outer tube 52, thereby increasing the height of the handlebar 34. To reduce the height of the handlebar 34, a person must apply force to the handlebar 34 against the spring force of the spring element 80 while the clamping device 60 is open. As soon as the force applied by the person exceeds the spring force of the spring element 80, the inner tube 50 moves in the retraction direction.

[0026] This provides a handlebar stem 38 with a height adjustment of the handlebar 34, whereby even in the absence of a mechanical fixation of the inner tube 50 to the outer tube 52, a surprising retraction of the inner tube 50 and thus an unexpected lowering of the handlebar 34 can be reliably prevented.

Claims

[1] Handlebar stem (38) for a bicycle (10), with a length-adjustable, telescopically designed fastening device (40) for attaching a handlebar (34) to a front fork (30), wherein the fastening device (40) is designed such that the handlebar (34) is adjustable between different heights, and wherein the fastening device (40) has an outer tube (52) and an inner tube (50) connected telescopically to the outer tube (52) and connected to the outer tube (52) in a manner that prevents rotation about a longitudinal axis, wherein the fastening device (40) has a hydraulic damper (70) which has a piston (77) fixedly connected to the inner tube (50) and two fluid chambers (72, 74) arranged inside the outer tube (52) and separated from each other by the piston (77), wherein characterized by , that the piston (77) of the damper (70) has a first hydraulic passage opening (82) designed as an inlet opening (83) and a second hydraulic passage opening (84) designed as an extension opening (85), through which the two fluid chambers (72, 74) can be fluidically connected to each other, a first check valve (86) is arranged at the inlet opening (83) and a second check valve (88) is arranged at the outlet opening (85), the two check valves (86, 88) are designed in such a way that the first check valve (86) only allows a hydraulic mass flow between the two fluid chambers (72, 74) during a retraction movement of the inner tube (50) and the second check valve (88) only allows a hydraulic mass flow between the two fluid chambers (72, 74) during an extension movement of the inner tube (50). [2] Handlebar stem (38) according to claim 1, characterized by, that a spring element (80) is arranged in the longitudinal direction between the inner tube (50) and the outer tube (52), wherein the spring element (80) is designed such that the spring element (80) loads the inner tube (50) in the extension direction. [3] Handlebar stem (38) according to claim 1 or 2, characterized by , that the inner tube (50) and outer tube (52) are connected to each other in a twist-proof manner via a spring-groove connection (56). [4] Handlebar stem (38) according to one of the preceding claims, characterized by , that the fastening device (40) has a clamping device (60) which is arranged on an outer circumferential surface of the outer tube (52), wherein the inner tube (50) can be fixed in different positions by means of a deformation of the outer tube (52) caused by the clamping device (60). [5] Handlebar stem (38) according to claim 4, characterized by, that the clamping device (60) has a slotted clamping ring (62) and an actuating lever (64), wherein the actuating lever (64) is connected via an eccentric section to one free end of the slotted clamping ring (62) and to a bolt (66) connected to the other free end of the slotted clamping ring (62). [6] Handlebar stem (38) according to one of the preceding claims, characterized by , that the inlet opening (83) has a smaller diameter than the outlet opening (85). [7] bicycle (10), with a bicycle frame (12), a front fork (30) which is rotatably attached to the bicycle frame (12) about a longitudinal axis, a handlebar (34), and a handlebar stem (38) according to one of claims 1 to 6.

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