WO1996031297A1

WO1996031297A1 - Cableless governor control

Info

Publication number: WO1996031297A1
Application number: PCT/CA1996/000208
Authority: WO
Inventors: Michael E. S. Lawrence; James Andrew Smith
Original assignee: Lawrence Michael E S; James Andrew Smith
Priority date: 1995-04-05
Filing date: 1996-04-04
Publication date: 1996-10-10
Also published as: CA2146405A1; AU5263896A

Abstract

A device for controlling the engine speed of a gasoline engine driven pressure washer comprises a cylinder (3) having a machined bore which houses a piston (6), piston spring (10), and a connecting rod (8) with a drag nut (22). The cylinder is mounted on the gasoline engine in such a manner that the movement of the piston and connecting rod affects the movement of the engine governor arm, thus controlling the speed of the engine. A hydraulic line (18) connects the cylinder to the pressure washer. When the trigger shutoff gun is closed, the pressure washer system pressure falls to near zero, and the spring (10) forces the piston (6) and connecting rod (8) back into the cylinder such that the drag nut contacts the engine governor arm (24), drawing it back and thereby slowing the engine. When the trigger shutoff gun is opened, the resultant rise in pressure is transmitted to the piston, forcing it back against the spring, extending the connecting rod and releasing the governor arm, thus allowing the engine speed to increase to its throttle setting. The opening and closing of the trigger shutoff gun in the pressure washer system causes the hydraulic line to be pressurized or de-pressurized, causing the piston to move back and forth in the cylinder.

Description

Cableless Governor Control

A cableless governor control is a device used on gasoline-engine-driven pressure washers to slow the engine down when the pressure washer system shutoff gun is closed, and to allow the engine to speed up again when the shutoff gun is opened.

Existing devices to control engine speed use system pressure changes resulting from opening and closing the trigger shutoff gun to activate a spring-loaded piston which in turn is connected to the engine throttle lever by means of a cable. Because these devices are mounted on the pressure washer pump, the cable can be quite long. The cable on these devices are obtrusive and therefore are easily snagged and broken; they slip; they offer resistance to, and may retard, the movement of the piston. They connect directly to the engine throttle lever, prohibiting independent use of the throttle.

What is needed is a cableless governor control that permits the operator to independently control the engine throttle. The present invention is directed towards a hydraulic cylinder containing a spring-loaded piston with a connecting rod and drag nut. The cylinder assembly is mounted to a gasoline engine by means of a bracket. This bracket is of two types: a Honda* engine mounting bracket or a universal mounting bracket. A hydraulic high pressure line connects the cylinder to the pressure washer system. When the device is mounted to the engine, the connecting rod and drag nut are positioned so that when the pressure washer system pressure is near zero, (brought about when the trigger shut off gun is closed), the spring forces the piston and connecting rod back in the cylinder and the drag nut contacts the engine governor arm, drawing it back, hence slowing the engine.

When the trigger shutoff gun is opened, the resultant rise in pressure is transmitted to the piston, forcing it back against the spring, releasing the governor arm. thus allowing engine speed to increase to its throttle setting.

According to one aspect of the invention, there is provided a device for limiting the speed of an engine driving a pressure washer system, the engine having a governor arm, comprising: (a) a connecting rod having a first end and a second end. the first end being adapted to releasably engage the governor arm and thereby constrain the locus of the governor arm, and

(b) means responsive to the pressure washer system pressure for moving the connecting rod.

According to another aspect of the invention there is provided a speed limited engine driven pressure washer system, comprising: (a) a pressure washer system, (b) an engine having a governor arm and adapted to drive the pressure washer system,

(c) a connecting rod having a first end and a second end, the first end being adapted to releasably engage the governor arm and thereby constrain the locus of the governor arm, and

(d) means responsive to the pressure washer system pressure for moving the connecting rod.

According to still another aspect there is provided a method of limiting the speed of an engine driving a pressure washer system, the engine having a governor arm, comprising:

(a) adjusting the position of a connecting rod according to the pressure washer system pressure, and

(b) releasably engaging the governor arm with the connecting rod to constrain the locus of the governor arm.

These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where:

Figure 1 is a sectional side view of a cableless governor control embodying the invention;

Figure 2a is a perspective view of a bracket for mounting the cableless governor control of Figure 1 to a Honda* engine; and Figure 2b is a perspective view of a universal bracket for mounting the cableless governor control of Figure 1 to an engine.

The invention, as exemplified by a preferred embodiment, is described with reference to the drawings in which Figure 1 shows a cylinder body (4) which is of hexagonal stock machined to receive a piston (6), a connecting rod (8), and a piston spring (10). The piston (6) is machined for an "o" ring (12) and a back-up ring (14). A high-pressure pipe fitting (16) is screwed into one end of the cylinder body (4) and a high-pressure line (18) is connected to it. The other end of the cylinder body (4) is threaded to receive a guide nut (20) for the connecting rod (8). The external end of the connecting rod (8) is threaded and a drag nut (22) is attached to it. The clearance between the connecting rod (8) and the governor arm (24) is such that they never contact each other. Only the drag nut (22) contacts the governor arm (24).

Figure 2a shows a mounting bracket (26a) which is mounted to a Honda* engine by two bolt holes (28a) and (30a). The cylinder body (4) fits inside a bracket clamp (32a) and is held securely by a clamp nut (34a) and a clamp bolt (36a). A grub screw (38a) elevates the cylinder body (4) up or down to obtain the necessary clearance between the connecting rod (8) and the engine governor arm (24).

Figure 2b shows a universal mounting bracket (26b) for mounting on engines other than Honda* engines.

When the trigger shutoff gun of a pressure washer equipped with a bypass/unloader is closed, the pressure in the hydraulic line ( 18) drops to or nearly to zero and the piston spring (10) forces the piston (6) back, drawing the connecting rod (8) and drag nut (22), and hence also the engine governor arm (24). Thus, the engine speed is reduced to an idle. When the trigger shutoff gun is opened, the pressure in the hydraulic line ( 18) rises, forcing the piston (6) and connecting rod (8) back against the spring (10), releasing the governor arm (24) which returns to its normal position, allowing the engine speed to return to the speed dictated by the position of the engine throttle lever. Because the cableless governor control controls the engine governor, not the throttle lever, the throttle can still be used to adjust engine speed in the operating mode. The connecting rod is not mechanically attached to the engine governor arm. therefore in no way does the cableless governor control have any control over the governor to increase engine speed. Its only function is to decrease engine speed when the trigger shutoff gun is closed. Because the cableless governor control device mounts out of harm's way, it is less likely to be damaged by external impacts.

Although only a single embodiment of the present invention has been described and illustrated, the present invention is not limited to the features of this embodiment, but includes all variations and modifications within the scope of the claims.

It is contemplated that the cableless governor control can be applied to any internal combustion engine driven system where a fluid is pressurized.

It is further contemplated that the cableless governor control can also be used to push a governor arm as well as pull it.

It is still further contemplated that the cableless governor control could be used to push or pull a throttle lever.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A device for limiting the speed of an engine driving a pressure washer system, the engine having a governor aim, comprising: (a) a connecting rod having a first end and a second end, the first end being adapted to releasably engage the governor arm and thereby constrain the locus of the governor arm, and (b) means responsive to the pressure washer system pressure for moving the connecting rod.

2. A device as in claim 1 wherein the moving means comprises:

(a) a housing defining a longitudinal bore and having a first end and a second end, the second end of the housing defining a hole adapted to receive the second end of the connecting rod into the bore,

(b) a piston adapted to occupy the bore and operable to slide there through, (c) means for connecting the second end of the connecting rod to the piston,

(d) means for supplying a force to the piston, directed substantially parallel to the bore toward the first end of the housing, and

(e) a pressure fitting passing through the first end of the housing to the bore, adapted to receive a fluid from the compressor system and to direct it into the bore.

3. A device as in claim 2 wherein the force applying means is a spring.

4. A device as in claim 2, further including:

(a) a drag nut attached to the first end of the connecting rod.

5. A speed limited engine driven pressure washer system, comprising: (a) a pressure washer system,

(b) an engine having a governor arm and adapted to drive the compressor system,

(c) a connecting rod having a first end and a second end, the first end being adapted to releasably engage the governor arm and thereby constrain the locus of the governor arm, and (d) means responsive to the pressure washer system pressure for moving the connecting rod.

6. A device as in claim 5 wherein the moving means comprises: (a) a housing defining a longitudinal bore and having a first end and a second end. the second end of the housing defining a hole adapted to receive the second end of the connecting rod into the bore,

(d) means for applying a force to the piston, directed substantially parallel to the bore toward the first end of the housing, and

(e) a pressure fitting passing through the first end of the housing to the bore, adapted to receive a fluid from the pressure washer system and to direct it into the bore.

7. A device as in claim 6 wherein the force applying means is a spring.

8. A device as in claim 6 , further including:

(a) a drag nut attached to the first end of the connecting rod.

9. A method of limiting the speed of an engine driving a pressure washer system, the engine having a governor arm, comprising: