Combination hydraulic master cylinder

Abstract

A combination hydraulic master cylinder comprising two typically parallel pumps disposed within adjacent compartments within a common body of the combination hydraulic master cylinder. Each pump's piston physically pressurizes hydraulic fluid that has been separately drawn into its respective cylinder and in hydraulic isolation, however the proximate location of the independent pumps allows for convenient operation using one hand on one handlebar with reduced congestion of space rather than the more conventional arrangement of two separate master cylinders. The pistons are actuated mechanically using dedicated levers mounted externally to the cylinders. The levers are adjustable in the manner to which they are disposed to the pistons. One lever is oriented such that it is operable using a finger pull action; the second lever is oriented such that it is operable using a thumb push action.

Claims

1. A combination hydraulic master cylinder, for use in actuating two hydraulic circuits comprising: a body comprising two bores, each bore comprising an opening, a hydraulic outlet, and an internal port for venting of air and hydraulic fluid charging; two pumps, one within both said bores; said two pumps each adapted to pressurize hydraulic fluid through said bore to an external hydraulic circuit when force is applied to the pump from the opening side of the bore; said pumps comprising a piston having a diameter, a seal arrangement permitting venting of air and charging of fluid, a return spring, a retaining clip, and a port within the bore communicating with an external fluid reservoir, and said force being achieved by means of a lever acting upon the pump about a fixed pivot point external to the bore; wherein the diameter of said pump determines the amount of fluid displaced according to the linear movement of the pump and the pressure within the hydraulic circuit is similarly determined by the external force on the pump; wherein the orientation of such external levers permits simultaneous or independent operation without interference; wherein the body is mountable on a fixed member in a manner which does not interfere with the operation of either of the two levers and the fixed member provides a convenient purchase point for the hand of the operator of the vehicle to which the combination hydraulic master cylinder is attached; the hydraulic circuits operated by the two pumps are independently connected using banjo bolts and hydraulic hoses to the body of the combination hydraulic master cylinder;

2. The combination hydraulic master cylinder claim 1, wherein said two bores and pumps may or may not have identical dimensions, and accordingly the diameter and stroke of each pump can be varied in order to influence the amount of fluid displaced and in consequence the pressure within the hydraulic circuit is similarly determined by the external force on the pump;

3. The combination hydraulic master cylinder of claim 1, wherein the two bores may be displaced vertically and in parallel, or in any other orientation which lends itself to improved ergonomics of operation and ease of manufacture;

4. The combination hydraulic master cylinder of claim 1, wherein for ease of manufacture or for adaptability in use the two bores may be physically separated and demountable from each other, for assembly with the dedicated pumps and external levers in the location where permanent operation is desired;

5. The combination hydraulic master cylinder of claim 2, wherein for ease of manufacture or for adaptability in use the two bores may be physically separated and demountable from each other, for assembly with the dedicated pumps and external levers in the location where permanent operation is desired;

6. The combination hydraulic master cylinder of claim 3, wherein for ease of manufacture or for adaptability in use the two bores may be physically separated and demountable from each other, for assembly with the dedicated pumps and external levers in the location where permanent operation is desired;

7. The combination hydraulic master cylinder of claim 1, wherein the internal ports of each bore and pump may be combined within the combination hydraulic master cylinder body to allow for venting of air and hydraulic fluid charging of each hydraulic circuit independently or simultaneously, and advantage is thereby taken of said connected internal ports by said hydraulic circuits being supplied from a single shared reservoir.

8. The combination hydraulic master cylinder of claim 3, wherein the internal ports of each bore and pump may be combined within the combination hydraulic master cylinder body to allow for venting of air and hydraulic fluid charging of each hydraulic circuit independently or simultaneously, and advantage is thereby taken of said connected internal ports by said hydraulic circuits being supplied from a single shared reservoir.

9. The combination hydraulic master cylinder of claim 1, wherein the external force on the pump, being exerted in accordance with the orientation of such external levers may be such that the upper pump is operated by the fingers of one hand by way of pulling its lever towards the member on which the body is mounted, and the lower pump is operated by the thumb of the same hand by way of pushing its lever in a direction which is away from the member on which the body is mounted.

10. The combination hydraulic master cylinder of claim 9, wherein the external levers are adapted in such a way in respect of their orientation, length and shape, and means of fixing to the pivot point of the combination hydraulic master cylinder body such that adjustments may be made to suit the size of the hand and strength of the fingers and thumbs of the operator.

11. The combination hydraulic master cylinder of claim 1, wherein the body is rigidly but adjustably mounted to a vehicle handlebar using a screwed clamp, said handlebar providing a convenient purchase point for the operator of the vehicle with which to support and balance himself on the vehicle but also facilitating unhampered operation of either of the two levers connected to the two actuated circuits by way of the hydraulic pumps;

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0017] Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout.

[0018] FIG. 1 shows a free body view of an embodiment of the present combination hydraulic master cylinder.

[0019] FIG. 2 shows a view of the combination hydraulic master cylinder depicted in FIG. 1 as it would be mounted on a handlebar.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the combination hydraulic master cylinder. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for a motorcycle. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.

[0021] The present invention is a combination hydraulic master cylinder that comprises two independent hydraulic pumps in one body, typically but not exclusively, vertically disposed. When actuated upon by an external lever, the pumps which are made up of a piston and sealing arrangement are designed to physically pressurize hydraulic fluid that is either existing within the cylinder and associated hydraulic circuit, or drawn into the cylinder as air is displaced when the external force on the piston is relaxed. The configuration of the body housing the two pumps is such that the separate levers acting on the piston and seal assemblies can be oriented in such a way that when mounted on a handle bar, the hydraulic circuits may be actuated by fingers in the first case, and thumb in the second case. By combining two pumps in one body in this way, the space required to mount two independent hydraulic master cylinders in one place on a motorcycle is reduced.

[0022] Referring now to FIG. 2, the upper hydraulic master cylinder is formed in the body (item 10) of the assembly with the near end sealed against pressure with, conventionally, an exit port tapped to connect an external hydraulic circuit (the tapped port is not shown in the drawing). The far end of the upper cylinder formed in the body is open to allow the installation of a piston, seals and return spring. The far end cylinder exits within a slot by which a lever arrangement (item 30) with pivot pin (item 40) can be attached after the aforementioned piston has been installed, with a retaining ring to capture the piston, seals and return spring once installed. Once mounted on the handlebar, the lever and pivot pin allow for a thrusting displacement of the piston by the application of a pulling force on the lever. The lever/pin/slot design is commonplace in prior art whereby the actuation against the piston requires the use of one to four fingers.

[0023] Paired in combination with the upper hydraulic master cylinder within the body, the lower hydraulic master cylinder is similarly formed in the body (item 10), but this time opposite in orientation with the far end sealed against pressure with, conventionally, an exit port tapped to connect a second external hydraulic circuit (again the tapped port is not shown). The near end of the lower cylinder formed in the body is open to allow the installation of a second piston, seals and return spring. The near end cylinder exits within a slot by which a lever arrangement (item 31) with pivot pin (not shown) can be attached after the piston has been installed, here again with a retaining ring. The lever and pivot pin allow for displacement of the piston by the application of a pushing force on the lever. A different design of lever to that for the upper master cylinder is provided configured to suit operation by the thumb.

[0024] Accordingly in this example but not exclusively, in use the device provides for two hydraulic circuits being operated with one hand on a motorcycle whereby the engine's clutch is operated by the fingers of the left hand using the pull lever (item 30), and the rear brake is operated with the thumb of the left hand pushing on the push lever (item 31)

[0025] Preferably, the most likely means by which the assembly is secured to the handlebar (item 20) is by clamp arrangement (item 11) providing rigid attachment behind the upper cylinder without interference with the push lever (item 31) below. The force applied by pulling the clutch lever is in the same plane as the handlebar with no significant turning moment being applied, however the clamp must be such that it can resist the turning moment which acts on the combination hydraulic master cylinder body as the rear brake is applied.

[0026] Hydraulic fluid is supplied by a reservoir to each cylinder (items 50 and 51). These could be combined into just one if operating conditions permit.

[0027] A bleed nipple must be provided for each hydraulic circuit. Sometimes these are on the body, and sometimes these are on the banjo bolt connection which secures the hydraulic circuit to the pump. Space and access will be the prevailing factor here.

[0028] It is therefore submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art.

[0029] With respect to the above description then, it is to be realized that the optimum dimensional and spatial relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

[0030] Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.