Patent Application
20060038034
This invention pertains to pressure washing machines and particularly to pressure washing machines supported on wheels.
Many portable pressure washing machines are mounted on wheels and include an internal combustion engine and an associated pump mounted on a frame. The operation of the engine creates substantial vibration in the frame of the pressure washer and this vibration can be translated into movement of the pressure washing machine along the surface on which it rests. This is highly undesirable. In order to reduce such undesirable movement of the machine when it is running, it has been usual practice to fabricate the frames for the machines from heavy steel plate, with the frame components welded together, and with stiffening ribs to rigidify the frame to cause machine vibration to be transmitted from the engine to the wheels where the vibrations can be absorbed sufficiently to allow the machine to remain at rest when the motor is running.
Developing demand for lighter weight portable pressure washing machines has not been satisfactorily met because the fabrication of pressure washer frames from aluminum, thinner gauge mild steel or stainless steel, or from other lighter weight materials does not result in the transmission of sufficient engine vibration to the wheels such that pressure washers with frames fabricated from lighter weight materials tend to vibrate excessively and “walk” along the surface on which they rest.
One manufacturer of pressure washing machines employs rubber vibration isolators mounted between the internal combustion engine and the machine frame. This structure has not been found to sufficiently dampen the vibrations to prevent the undesired movement of the pressure washing machine when its engine is running.
A need exists for a vibration absorbing structure of low cost and low complexity which will permit pressure washing machines to be fabricated with frames of lightweight materials without the need to use brakes or wheel blocks to keep the pressure washing machine in place when in operation.
The present invention provides an improved vibration absorbing structure for a portable pressure washing machine supported on wheels.
A vibration plate whose area substantially exceeds the footprint of the engine of the pressure washing machine is mounted to the base of the engine. Multiple vibration isolating elastomeric cylinders are interposed between the vibration plate and the frame of the pressure washer. The vibration plate may be rectangular and may extend from beneath the engine nonsymmetrically with the plate extending furthest from under the side of the engine from which the engine drive shaft extends. The isolators are positioned near each corner of the vibration plate and are fixed to both the vibration plate at their upper ends and to the machine frame at their lower ends. The addition of the vibration absorbing structure permits frame components to be bolted together rather than welded, allows use of lighter weight frame materials such as aluminum and thin gauge mild steel or stainless steel to be used for frame components, eliminates the need for stiffening ribs on frame components, and reduces wear on the pressure washer components.
Therefore objects of the invention include: providing a lighter weight portable pressure washing machine which will remain at rest during operation; providing a portable pressure washing machine with a frame which can be fabricated from stainless steel or aluminum; and providing a portable pressure washing machine with a frame which requires no stiffening ribs or welding of component parts. These and other objects will be understood from a careful review of the detailed description and claims which follow.
A portable pressure washer 2 exemplary of the present invention is illustrated in
In examining
Plate member 30 is substantially planar and constructed of thin rigid metal, preferably the same metal as frame 10 which may be constructed of light weight mild or stainless steel, or of aluminum.
Vibration isolators 22 support plate member 30 above top deck 28 and are fixed to plate member 30 and to top deck 28 by end studs 38.
Referring now to
Multiple bolt holes 42 are provided in plate member 30 such that engines 6 of varying sizes can be mounted to plate member 30 by using alternative sets of holes 42 for mounting bolts 36.
Isolators 22 comprise solid elastomeric cylinders 44, preferably of rubber or the like, with a hardness of approximately fifty durometer. Studs 36 are coaxial with isolators 22 and do not extend through elastomeric cylinder 44 but rather separate studs 36 extend from the opposing first and second ends 46, 48 respectively of each elastomeric cylinder 44. Each elastomeric cylinder 44 is preferably one inch in diameter and one inch in length though variations of these dimensions may be found to be useful depending on the size and weight of engine 6 and pump 8 to be supported.
It can be seen in
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations of the embodiments are possible in light of the above disclosure or such may be acquired through practice of the invention. The embodiments illustrated were chosen in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and by their equivalents.
