A control assembly for a hydraulic brake of a handlebar-steered vehicle

Abstract

The transmission mechanism for actuating a brake master cylinder (13) integrated into the tube (10) of a handlebar comprises a connecting rod (30) having a first end (31) rotatably connected about a spherical coupling to an end (14a) of a piston (14) of the brake master cylinder, and another end (32) rotatably connected about an intermediate transmission lever (17).

Description

[0001] A control assembly for a hydraulic brake of a handlebar- steered vehicle

[0002] Technical field

[0003] The present invention relates to the field of handlebar-steered vehicles equipped with a hydraulic brake. The invention refers to an integrated control assembly for a hydraulic brake of a handlebar- steered vehicle. More particularly, but not exclusively, the present assembly is applicable to bicycles.

[0004] Background art

[0005] As is known, many bicycles and other handlebar-steered vehicles are equipped with a hydraulic braking system, where a brake master cylinder, actuated by a brake control lever mounted on the handlebar, controls a brake caliper associated with each wheel via a flexible hydraulic hose. The brake master cylinder and an associated reservoir containing a reserve of brake fluid are mounted on the handlebar near the control lever. The flexible hose runs externally along the handlebar.

[0006] US 2019 / 0152457 Al discloses a control assembly for a hydraulic brake or clutch of a handlebar- steered vehicle. A brake master cylinder or master cylinder is disposed inside a handlebar tube; a flexible hydraulic hose is hydraulically connected to the master cylinder and runs inside the handlebar tube. A manual control lever, external to the handlebar, is articulated to a piston in the master cylinder via a pull-rod transmission element that exerts a pulling force on the piston when the control lever is actuated.

[0007] WO 2023 / 187667 Al discloses a control assembly for a hydraulic brake for a handlebar- steered vehicle having a handlebar tube that contains a brake master cylinder inside it. The brake master cylinder comprises a cartridge suitable for being mounted inside the handlebar tube. The cartridge forms a longitudinally extended cavity inside it, in which a piston is partially received. The control assembly comprises a transmission mechanism, mountable on the handlebar in a position interposed between a brake control lever rotatably mountable on the exterior of the handlebar about a first transversal axis and the piston, to transmit a longitudinal thrust to the piston inside the handlebar. The transmission mechanism comprises an intermediate transmission lever mountable on the handlebar tube rotatably about a second transversal axis. When the intermediate lever is actuated, it rotates and one of its free ends engages in a thrust relationship by sliding against an end of the piston.

[0008] Summary of the invention

[0009] It is an object of the present invention to improve the accuracy in transmitting the brake actuation forces, and to extend the durability of the transmission mechanism that transmits the actuation movement, which the user exerts on the manual control lever, to the piston of the brake master cylinder.

[0010] The above and other objects and advantages, which will be better understood herein after, are achieved, according to the present invention, by a hydraulic brake control assembly having the features set forth in claim 1. Preferred embodiments are set forth in the dependent claims.

[0011] In summary, the transmission mechanism of the control assembly comprises a connecting rod having a first end constrained according to a spherical coupling to an end of the piston, and a second end rotatably constrained about a transversal axis on the intermediate transmission lever.

[0012] The connecting rod improves the transmission of longitudinal forces imparted to the piston. The absence of sliding between the intermediate lever reduces friction, reduces the effort required from the user for braking, reduces wear on the surface of the contacting parts, extending the durability of the assembly, and eliminates play between the piston and the chain of components that move it.

[0013] Brief description of the drawings

[0014] A few preferred but not limiting embodiments of a hydraulic brake control assembly according to the invention will now be described. Reference is made to the accompanying drawings, in which:

[0015] Figure 1 is a sectional view of a hydraulic brake control assembly integrated into a handlebar tube of a handlebar-steered vehicle, with a manual control lever; and

[0016] Figures 2, 3 and 4 are perspective views of two components of the control assembly shown in Figure 1.

[0017] Detailed description

[0018] Referring to the drawings, a control assembly for a hydraulic brake of a handlebar- steered vehicle, in particular but not exclusively a bicycle, is integrated into a handlebar tube 10), and more particularly into a rectilinear end portion of the handlebar tube 10.

[0019] The handlebar tube 10 defines a central axis x, herein called "longitudinal". Throughout this specification and in the appended claims, terms indicating orientations and directions, such as "longitudinal", "transversal", "external", and "internal", are to be construed with reference to the longitudinal axis x, unless otherwise noted.

[0020] The control assembly comprises a brake master cylinder 13, mounted internally in the handlebar tube 10, to apply pressure to a braking fluid for actuating at least one brake of the vehicle.

[0021] The brake master cylinder comprises a cartridge 12 and a piston 14. The cartridge has an axially elongated cylindrical shape and is configured to be fixedly mounted inside the handlebar tube 10. The cartridge 12 internally forms an axially extended cavity 15. At least part of the piston 14 is received in an axially slidable manner in the cavity 15.

[0022] A brake control lever 11 can be mounted on the handlebar tube 10 rotatably about a first axis I la that is transversal to the longitudinal axis x.

[0023] A delivery port (not illustrated) is formed in the axially extended cavity 15, located at an end of the cavity 15 that is facing, in use, an end 10a of the handlebar tube, to the left in Figure 1. The delivery port serves for the passage of brake fluid, used for the actuation of the hydraulic brake.

[0024] The piston 14 is actuatable by the brake control lever 11 via a transmission mechanism 16.

[0025] The transmission mechanism 16 is mountable on the handlebar 10 and is operatively interposed between the brake control lever 11 and the piston 14, to transmit an axial thrust to the piston inside the handlebar.

[0026] The transmission mechanism 16 comprises an intermediate transmission lever 17 mounted to the handlebar tube 10 rotatably about a second transversal axis 17a.

[0027] According to one embodiment, the intermediate transmission lever 17 is made as a rocker arm, and has an arm 17c that penetrates into the handlebar tube 10 through a through opening 10c formed in the handlebar.

[0028] The transmission mechanism 15 comprises a connecting rod 30 having a first end 31 rotatably connected by a spherical coupling 31a to an end 14a of the piston 14 and a second end 32 rotatably connected about a fourth transversal axis 32a to the intermediate transmission lever 17.

[0029] According to a preferred embodiment, a cylindrical cavity 27 extending transversally is formed in the end of the arm 17c of the intermediate lever 17. Coaxially mounted within the cylindrical cavity 27 is a transversal connecting element 28 (Figure 2), preferably metallic, with a threaded hole 29 oriented longitudinally in the installed condition.

[0030] The second end 32 of the connecting rod 30, having a terminal portion correspondingly threaded to the threaded hole 29, can be threadedly connected in the threaded hole 29.

[0031] A lining sleeve 33 made of plastic material (Figure 3), advantageously of low-friction material, e.g., PTFE, can be interposed between the transversal connecting element 28 and the cylindrical cavity 27. In the example of Figures 3 and 4, the lining sleeve 33 has a lateral through hole 34 aligned with the threaded hole 29 to allow the passage of the second end 32 of the connecting rod 30.

[0032] Optionally, to facilitate assembly and promote the alignment of holes 29 and 34, the lining sleeve 33 may have an internal cavity 35 of non-circular section, congruent in shape with the shape of the external surface of the transversal connecting element 28.

[0033] According to one embodiment, the first end 31 of the connecting rod 30 may be shaped as a spherical head, inserted into a corresponding concave seat 36 formed in the end 14a of the piston 14, thereby forming a spherical joint.

[0034] The locking of the spherical head 31 in the concave seat 36 may be ensured by a cup- shaped locking element 37 with a flat wall having a through hole of a diameter smaller than the diameter of the spherical head 31, and an externally threaded cylindrical wall suitable for engaging in a corresponding threaded cylindrical seat formed in the cartridge 12 or attached thereto.

[0035] The cartridge 12 may be made of plastic material, or a metallic material, such as aluminum or its alloys.

[0036] The intermediate transmission lever 17 is actuatable by the brake control lever 11 to exert a longitudinal thrust action on the piston, causing it to advance in the longitudinal cavity 15 towards the delivery port (not shown).

[0037] Inside the cavity 15, a compression spring 19 is interposed between the piston 14 and the bottom of the cavity 15, on the side of the delivery port. The spring 19 urges the piston 14 away from the delivery port.

[0038] In the example shown in Figure 1, the transmission mechanism 16 may also comprise a second lever 22, rotatably mounted on the brake control lever 11 around a transversal rotation axis 22a. According to the particular embodiment illustrated, the second lever 22 is mounted on the handlebar tube 10 rotatably about a transversal rotation axis parallel or coincident with the transversal axis I la around which the brake control lever 11 is rotatably mounted.

[0039] An idle roller 21, freely rotatable about a transversal rotation axis, is mounted in this example on the second lever 22.

[0040] When the brake control lever 11 is actuated, by pulling it towards the handlebar tube 10, the roller 21 acts in a thrust relationship by rolling against and along a surface 23 of the intermediate transmission lever 17.

[0041] The second lever 22 can be biased, together with the brake control lever 11, by a spring (not shown) that tends to bring the brake control lever 11 closer to the handlebar tube 10, simultaneously urging the second lever 22 against an adjustment screw 25 mounted on the brake control lever 11.

[0042] The adjustment screw 25, optional, serves to adjust the rest position of the brake control lever 11, depending on the size of the user's hand, particularly based on the greater or lesser length of the user's fingers. When the brake control lever 11 is pulled towards the handlebar tube 10, the second lever 22 is urged by the adjustment screw 25 and rotated counterclockwise around the axis 22a.

[0043] In an alternative embodiment (not shown), the roller 21 may be rotatably mounted directly on the brake control lever 11. In such an embodiment, the second lever 22 and the adjustment screw 25 are absent.

[0044] The brake control lever 11 is in this example mounted on the handlebar tube 10 by means of two complementary mounting half-rings 39.

[0045] In use, by actuating the brake control lever 11, i.e. pulling it in a manner known per se towards the handlebar tube 10, the brake control lever 11 rotates (Figure 1) counter- clockwise, also pulling the optional second lever 22 with it, which also rotates counterclockwise. The roller 21, by rolling along the shaped surface 23 of the intermediate transmission lever 17, causes the latter to rotate clockwise, pushing the piston 14 to the left, in an actuation direction directed towards the end 10a of the handlebar, pushing a quantity of brake fluid that fills the cavity 15 towards the delivery port. Through non-illustrated channels, the brake fluid is conveyed towards the brake caliper (not shown) on a vehicle wheel.

[0046] Although specific embodiments of the invention have been described, it should be understood that this disclosure has been provided purely by way of illustration and that the invention is not to be limited in any way thereby. Various modifications will be apparent to those skilled in the art, in light of the foregoing examples. The scope of the invention is limited only by the appended claims.

Claims

CLAIMS1. A control assembly for a hydraulic brake of a handlebar- steered vehicle having a handlebar tube (10) containing a brake master cylinder (13) within it, wherein the brake master cylinder comprises: an axially elongated cylindrical cartridge (12) configured to be fixedly mounted within the handlebar tube (10), the cartridge forming an axially extended cavity (15) internally; and a piston (14) axially slidable and received at least partially in the cavity (15); and wherein the control assembly comprises a transmission mechanism, mountable on the handlebar tube and operatively interposed between a brake control lever (11) rotatably mountable on the exterior of the handlebar tube about a first transversal axis (I la) and the piston (14), to transmit a longitudinal thrust to the piston within the handlebar tube, and wherein the transmission mechanism comprises an intermediate transmission lever (17) rotatably mountable on the handlebar tube (10) about a second transversal axis (17a); characterized in that the transmission mechanism comprises a connecting rod (30) having a first end (31) rotatably connected about a third transversal axis at one end (14a) of the piston (14) and a second end rotatably connected about a fourth transversal axis (32a) on the intermediate transmission lever (17).

2. A control assembly according to claim 1, wherein the first end (31) of the connecting rod (30) is shaped as a spherical head, inserted into a corresponding concave seat (36) formed in the end (14a) of the piston (14).

3. A control assembly according to claim 1 or 2, wherein the intermediate transmission lever (17) is made as a rocker arm and is provided with an arm (17c) that penetrates into the handlebar tube (10) through a through opening (10c) formed therein.

4. A control assembly according to claim 3, wherein formed in the end of the arm (17c) of the intermediate lever (17) is a cylindrical cavity (27) extending transversally within which a transversal connecting element (28) is coaxially mounted, forming a rotatableconnection around said fourth transversal axis (32a).

5. A control assembly according to claim 4, wherein the transversal connecting element (28) has a threaded hole (29) oriented longitudinally in an installed condition, the second end (32) of the connecting rod (30) having a terminal portion threaded correspondingly to the threaded hole (29) and threadedly connected to the threaded hole (29).

6. A control assembly according to claim 5, wherein a lining sleeve (33) made of low- friction plastic material is interposed between the transversal connecting element (28) and the cylindrical cavity (27).

7. A control assembly according to claim 6, wherein the lining sleeve (33) provides: a lateral through hole (34) aligned with the threaded hole (29), and an internal cavity (35) of non-circular section, congruent in shape with the shape of the external surface of the transversal connecting element (28).

8. An assembly comprising a handlebar tube (10) for a handlebar- steed vehicle and a hydraulic brake control assembly according to any one of the preceding claims.

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