Foldable bicycle frame

Abstract

The invention relates to a foldable bicycle frame (1) having a front part, which supports a front wheel during use, and a rear part (3), which supports a rear wheel during use. The front part (2) and the rear part (3) of the bicycle frame (1) are connected to each other by a joint (4) and are movable relative to each other between a use position and a transport position or a folded position. According to the invention, the joint (4) is provided in a joint block (14) which is configured as a separate fitting element and can be mounted on the front part (2) or on the rear part (3) of the bicycle frame (1) and in which the respective other part of the bicycle frame (1) is hingedly received.

Description

[0001] "Foldable bicycle frame"

[0002] Description:

[0003] The invention relates to a foldable bicycle frame according to the preamble of claim 1.

[0004] Foldable bicycle frames are well known in practice. The front and rear sections of the bicycle frame are connected by hinges, allowing the bicycle to be moved in a riding or use position. The foldable bicycle frames can also be folded or transported in a position where the length of the bicycle is significantly reduced, allowing the bicycle to be transported, for example, in the trunk of a car or stored in the luggage compartment of public transport. In the known foldable bicycle frames, the respective hinge is created by corresponding elements located on the front and rear sections of the bicycle frame.

[0005] The invention is based on the object of improving a generic bicycle frame in such a way that it enables a particularly economical provision of a folding bicycle to customers and allows for considerable design freedom in the manufacture of the front and rear frame parts. This object is achieved by a foldable bicycle frame according to claim 1. Further advantageous aspects, details, and embodiments of the invention emerge from the dependent claims and the description.

[0006] According to the invention, a foldable bicycle frame is proposed, having a front part which, in use, carries a front wheel, and having a rear part which, in use, carries a rear wheel, wherein the front part and the rear part of the bicycle frame are connected to one another by means of a joint and are movable relative to one another between a use position and a transport or folding position, wherein the joint is arranged in a joint block which is designed as a separate fitting element and can be mounted on the front part or the rear part of the bicycle frame and which receives the respective other part of the bicycle frame in an articulated manner.

[0007] In other words, the invention proposes not creating the joint through the corresponding design of the front and rear sections of the bicycle frame, but rather creating a separate joint block that is mounted on one of the two frame sections and articulates the other frame section. The joint block is manufactured as a separate component and only mounted on the corresponding frame section after the front and rear sections of the bicycle frame have been completed. Preparatory and follow-up work during the painting or coating process of the frame sections is considerably reduced because functional surfaces such as bearing seats, threads or contact surfaces are located on the joint block, meaning that the corresponding surfaces on the respective frame sections do not need to be masked or reworked. This represents an economic advantage in the manufacture of the bicycle frame.

[0008] A further economic advantage arises from the fact that the two frame sections are not connected to each other by the joint from the outset. Rather, the two frame sections can be packaged without being connected to each other, saving space, thus also reducing transport costs. The two frame sections can only be connected at the bicycle dealer or end customer's premises, where the joint block, which is already connected to one of the two frame sections by means of a joint, is mounted on the other frame section.

[0009] In known folding bicycle frames, elements of the joint, such as bearing seats, are welded to other elements of the respective frame section, e.g., to frame tubes of the front and / or rear sections. The use of the joint block according to the invention also allows materials that are not suitable for welding to be used to manufacture the front and / or rear sections. This, on the one hand, expands the design freedom in the selection of materials used for the bicycle frame and, on the other hand, can also support the production of a particularly economical bicycle frame by selecting correspondingly inexpensive materials.

[0010] Since the use of the joint block eliminates the need for welds on the front and / or rear sections of the bicycle frame, which would otherwise be necessary for the aforementioned elements of the joint, distortion that could otherwise occur on the bicycle frame in the area of ​​the joint is eliminated. Costly reworking to compensate for such distortion can therefore be eliminated, which also makes a bicycle frame according to the invention particularly economical to manufacture. Instead, the joint block can be manufactured as a forged component with high-precision, e.g. CNC-supported, post-processing, so that important dimensions of the foldable bicycle frame, such as the bearing seats, the pivot point of the joint and the alignment of the joint axis, can be precisely maintained and guaranteed without the need for post-processing.According to a further development, it can be provided that the joint block engages, in the manner of a pipe clamp, frame elements of the respective front part and / or rear part of the bicycle frame on which the joint block can be mounted.

[0011] The joint block can have a wide variety of connection surfaces for mounting on one of the two frame parts of the bicycle frame. In one embodiment, the joint block engages frame elements of the frame part to which the joint block is to be mounted, similar to a pipe clamp, so that the joint block can be mounted to this frame part in the manner of a clamp. Accordingly, the frame part in question can be completely painted, and only later is the joint block mounted to the already painted frame part.

[0012] Preferably, it can be provided that the joint block has two half-shells which can be connected to one another in such a way that frame elements arranged between the two half-shells are clamped between the half-shells.

[0013] The joint block can have individual areas that act as pipe clamps and, when placed against a frame part, can be clamped, while in other areas it is preferably designed without such a clamping option. In one embodiment, however, the joint block is made up of two parts, namely preferably two half-shells that can be placed on the respective frame part to which the joint block is to be mounted. This allows the clamping forces to be distributed over as large an area as possible, thus protecting the corresponding element of the frame part to which the joint block is mounted. The actual joint, which enables the folding process of the bicycle frame, is advantageously provided on only one of the two half-shells in this embodiment of the joint block, for example in the form of a joint sleeve with the bearing seats.

[0014] Furthermore, it can preferably be provided that the joint block can be fixed to a down tube and a seat tube of the front part.

[0015] Precise fixation of the joint block and thus precise alignment of the joint axis is achieved in one design by attaching the joint block to a down tube and a seat tube of the front section. In traditional frame tube designs with circular cross-sections, rotational movements of the joint block around the down tube as well as longitudinal movements along the down tube are prevented by also attaching the joint block to the seat tube. This results in a particularly simple yet particularly reliable fixation of the joint block to the front section of the bicycle frame.

[0016] According to one embodiment, it can be provided that the joint axis of the joint located in the joint block is aligned obliquely to the longitudinal axis of the bicycle frame in plan view.

[0017] The joint axis around which the rear part of the bicycle frame can be pivoted relative to the front part runs essentially transversely to the longitudinal axis of the bicycle frame and thus essentially transversely to the direction of travel of a bicycle having this bicycle frame. In order to enable a particularly compact pack size in the transport or folded position of the bicycle frame, in one embodiment the joint axis is aligned obliquely to the longitudinal axis of the bicycle frame when viewed from above. In this way, the rear wheel is guided laterally next to the front part of the bicycle frame during the folding process, so that the largest possible pivot angle can be achieved. Advantageously, it can be provided that the rear part of the bicycle frame is spring-loaded and supported on the front part.

[0018] The bicycle frame can be locked in both of its pivoting positions, i.e., in the riding or use position as well as, preferably, in the transport or folding position, thus preventing unintentional pivoting. Such a fixation can be particularly advantageous in the transport or folding position to ensure the compact pack size is maintained. In the riding or use position, however, pivoting mobility around the joint can be advantageous, namely if, in one embodiment, the rear part of the bicycle frame is spring-supported against the front part. Thus, the joint used for folding can also serve economically as a pivot bearing for a spring-loaded rear wheel.

[0019] According to a further development, it can be provided that the rear part of the bicycle frame has a bottom bracket housing and preferably the entire drive train of the bicycle is arranged in the rear part of the bicycle frame.

[0020] The bottom bracket can be located at the front or rear of the bicycle frame. In one embodiment considered advantageous, the entire drive train of the bicycle is located in the rear of the bicycle frame. For this purpose, the rear of the bicycle frame has a bottom bracket shell. By integrating the entire drive train into the rear of the bicycle frame, it is ensured that the distance between the bottom bracket and the rear wheel axle does not change during the pivoting movement about the joint axis. Firstly, this enables particularly economical production of the bicycle because, for example, a chain tensioner is no longer necessary, and secondly, drive elements such as a toothed belt can also be used, which structurally require a defined distance between the bottom bracket and the rear axle.For a bicycle powered exclusively by human power, the bottom bracket shell is advantageously designed as a separate housing, for example, in the form of a piece of tubing. For a motor-assisted bicycle, the bottom bracket shell is typically formed by the housing of a motor-gearbox unit.

[0021] Further features, details and advantages of the invention emerge from the wording of the claims as well as from the following description of embodiments based on the purely schematic drawings, whereby individual features or a combination of features of the illustrated embodiments can also be implemented independently of the remaining design.

[0022] Fig. 1 is a side view of a foldable bicycle frame in its riding or use position,

[0023] Fig. 2 the bicycle frame of Fig. 1 in its transport or folding position,

[0024] Fig. 3 is a side view of a joint block of the bicycle frame of Fig. 1,

[0025] Fig. 4 is a bottom view of the joint block of Fig. 3, and

[0026] Fig. 5 is a plan view of the folded bicycle frame of Fig. 2.

[0027] Fig. 1 shows a foldable bicycle frame 1 which has a front part 2 and a rear part 3, the rear part 3 being connected to the front part 2 via a joint 4. The front part has a head tube 5, a top tube 6, a down tube 7 and a seat tube 8 as frame tubes. The rear part 3 has lower chain stays 9 and upper seat stays 10 as frame tubes and connecting stays 11 which run essentially parallel to the seat tube 8 of the front part 2 and connect the chain stays 9 to the seat stays 10. The seat stays 10 end at the front at a distance from the seat tube 8. The rear part 3 is supported on the front part 2 of the bicycle frame 1 via a spring element (not shown in the drawing). At the upper end of the seat tube 8, an eccentric clamping lever can be seen as a quick release 12, which is used to attach and adjust the height of a seat post, which can accordingly extend to different distances into the seat tube 8.

[0028] Furthermore, it can be seen from Fig. 1 that the joint 4 is part of a joint block 14, which, in addition to the joint 4, also forms a seat tube clamp 15 and a down tube clamp 16. A bottom bracket shell 17 is part of the rear part 3 of the bicycle frame 1 and is located essentially below the seat tube 8.

[0029] Fig. 2 shows the bicycle frame 1 after the rear part 3 has been pivoted forward and downward about the joint 4 of the joint block 14, so that the bicycle frame 1 assumes its transport or folding position in Fig. 2. The bottom bracket shell 17 has also been pivoted together with the rear part 3.

[0030] Fig. 3 shows the joint block 14 in a side view. Reinforcing ribs 18 extend from the seat tube clamp 15 and the down tube clamp 16 to the joint 4. A joint housing 19 is visible from the joint 4, forming bearing seats for pivotally connecting the rear part 3 to the joint block 14. The side view clearly shows that the joint housing 19 is inclined and not aligned exactly perpendicular to the direction of travel or perpendicular to the longitudinal direction of the bicycle frame 1.

[0031] Fig. 4 shows the joint block 14 from below, looking toward the joint housing 19, over which the down tube clamp 16 runs. The seat tube clamp 15 is designed similarly to a pipe clamp, allowing it to grip the seat tube 8 and be secured thereto by means of a clamp. The angled position of the joint housing 19 is particularly clearly visible here.

[0032] Fig. 5 shows a plan view of the bicycle frame 1, which is in its transport or folded position according to Fig. 2. Due to the inclined position of the joint housing 19, the folding process has resulted in the rear part 3 below the front part 2 not being symmetrically aligned with the front part 2, but rather lying diagonally next to the front part 2. A rear wheel of a bicycle, which would be located in the rear part 3 of the bicycle frame 1 between the chain stays 9 and the seat stays 10, would accordingly be arranged laterally next to the frame tubes of the front part 2, so that a particularly compact packing size of a bicycle having this bicycle frame 1 is achieved.

[0033] The invention is not limited to one of the embodiments described above, but can be modified in many ways.

[0034] All features and advantages arising from the claims, the description, and the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in various combinations. Reference symbols:

[0035] 1 bicycle frame

[0036] 2 front part

[0037] 3 Rear part

[0038] 4 joint

[0039] 5 Head tube

[0040] 6 top tube

[0041] 7 Down tube

[0042] 8 seat tube

[0043] 9 Chainstay

[0044] 10 Seat stay

[0045] 11 Connecting strut

[0046] 12 quick release

[0047] 14 Joint block

[0048] 15 seat tube clamp

[0049] 16 down tube clamp

[0050] 17 Bottom bracket shell

[0051] 18 Stiffening rib

[0052] 19 Joint housing

Claims

Claims: 1 . A foldable bicycle frame (1 ), with a front part (2) which, in use, carries a front wheel, and with a rear part (3) which, in use, carries a rear wheel, wherein the front part (2) and the rear part (3) of the bicycle frame (1 ) are connected to one another by means of a joint (4) and are movable relative to one another between a use position and a transport or folding position, characterized in that the joint (4) is arranged in a joint block (14) which is designed as a separate fitting element and can be mounted on the front part (2) or the rear part (3) of the bicycle frame (1 ) and receives the respective other part of the bicycle frame (1 ) in an articulated manner.

2. Bicycle frame (1) according to claim 1, characterized in that the joint block (14) engages around frame elements of the respective front part (2) or rear part (3) of the bicycle frame (1) in the manner of a pipe clamp, on which the joint block (14) can be mounted.

3. Bicycle frame (1) according to claim 2, characterized in that the joint block (14) has two half-shells which can be connected to one another in such a way that frame elements arranged between the two half-shells are clamped between the half-shells.

4. Bicycle frame (1) according to one of the preceding claims, characterized in that that the joint block (14) can be fixed to a down tube (7) and a seat tube (8) of the front part (2).

5. Bicycle frame (1) according to one of the preceding claims, characterized in that the joint axis of the joint (4) located in the joint block (14) is aligned obliquely to the longitudinal axis of the bicycle frame (1) in plan view.

6. Bicycle frame (1) according to one of the preceding claims, characterized in that the rear part (3) of the bicycle frame (1) is spring-supported on the front part (2).

7. Bicycle frame (1) according to one of the preceding claims, characterized in that the rear part (3) of the bicycle frame (1) has a bottom bracket housing (17) and the entire drive train of the bicycle is arranged in the rear part (3) of the bicycle frame (1).

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