Patent Application
20070207042
The present invention relates to portable machines with fuel powered engines, and specifically to portable pressure washers with fuel powered engines.
One side effect of using a fuel powered engine to operate a pressure washer is that the engine generates a significant amount of heat during operation due to the combustion process. This generated heat causes the engine's exterior surfaces to become extremely hot during operation such that a user could easily become burned if directly contacting an exposed engine surface. Prior art pressure washers have used various covers or shrouds to enclose the engine to prevent users from contacting the engine. Because the covers are generally attached directly to the surface of the engine, the cover must be manufactured from a material with specific properties that allow the cover to accept the significant amount of heat transferred to it from the engine, or in the alternative, the dimensions of the cover (i.e. the thickness of the cover) must be such that the cover can accept the amount of heat generated and transferred to the cover.
Because covers for pressure washers must be robust enough to accept a significant amount of heat from an engine, it is often a design challenge to provide structures or components to store external tools that may be used with the pressure washer. Many current pressure washers have been designed to include a plurality of clips, rings, or other structures to retain external tools for use with the pressure washer, such as lances, spray guns, cords, nozzles, etc. The structures provided to store these tools is often attached to the handle, the cart, or other working parts of the pressure washer. Storing external components on these portions of the pressure washer makes the pressure washer bulkier and less maneuverable with the external tools installed than many users would prefer.
Because of heat or vibrational concerns, many previous shrouds that were mounted directly to the engine could not be formed to accept and retain external tools because of material considerations. Specifically, shrouds or covers that are mounted on an engine receive a significant amount of heat from the engine during operation and accordingly reach dramatically higher temperatures. Accordingly, shrouds were often manufactured with relatively thick or relatively heat resistant materials to withstand the increased temperatures. The design requirements for previous shrouds that were directly connected to an engine often prevented the shroud from including structures that were movable or had sufficient elasticity to accept and retain a tool such as a spray gun.
Additionally, shrouds that are directly mounted to an engine receive a portion or percentage of any vibrations created by the engine or pump during operation. Any external tools that are attached to the shroud receive any vibrations within the shroud and may become at least partially unstable with respect to the shroud during pressure washer operation. This unstable connection could lead to failure or breakage of the structures used to removeably accept the external tools, which reduces the operability and convenience of operating the pressure washer. Additionally, the relative movement between the vibrating shroud and the external tools during operation (because the external tools do not vibrate with the same harmonic frequency as the shroud because of their inertia) may create additional unpleasant noise, which often serves as a distraction and an annoyance to the user.
A pressure washer is provided that includes an engine that is operatively connected to a pump. Each of the engine and the pump are supported on a frame. A shroud is mounted to the frame independently of the engine and the pump wherein the shroud at least partially surrounds and encloses a portion of the engine.
Advantages of the present invention will become more apparent to those skilled in the art from the following description of the preferred embodiments of the invention that have been shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments, and its details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.
The features and advantages of the present invention may be better understood by reference to the accompanying drawings in which like reference numerals refer to like elements.
While this invention is susceptible of several different embodiments, this specification and the accompanying drawings disclose only some specific forms as examples of the invention. The invention is not intended to be limited by the descriptions in this specification or the drawings. Instead, the scope of the invention is provided in the claims.
Referring now to the figures, a shroud for a machine is provided. The shroud described below can be implemented with a multitude of different types of machines that include engines to operate a working member to perform a specific task. Additionally, the shroud described below may be implemented on various machines that include fuel powered engines, such as pressure washers, generators, or air compressors. Although the invention may be implemented with a variety of different types of machines, the design is fully described with specific references to use in a pressure washer. For the sake of brevity we do not fully describe the use of this concept with other types of machines although one of skill in the art, after fully reviewing the specification and drawings herein, will comprehend that this disclosure may successfully be implemented with other types of machines.
Turning now to
As understood by those of ordinary skill in the art, a fuel powered engine generates a large amount of heat during operation due to fuel combustion. While engines are provided with mechanisms for cooling, such as fins 42 and air flow (whether forced or natural circulation) past the external surfaces of the engine, these cooling mechanisms are not normally efficient enough to prevent the exterior surfaces of the engine 40 from dramatically increasing in temperature during engine operation. Accordingly, because the engine 40 is at an increased temperature during operation, the excess heat present on the exterior surfaces of the engine is transferred to neighboring components due to radiation and convection heat transfer, and transferred to components that are in contact with the engine surface due to conduction heat transfer. Therefore, components of the pressure washer that are in contact with or simply in close proximity to the engine 40 experience a significant amount of heat from the engine 40 during operation and accordingly reach higher temperatures during engine operation.
The engine 40 and associated components such as the fuel tank 14 and the pump 46 are normally rigidly mounted on the frame 60. The frame 40 additionally serves as the mounting point for a pair of wheels 12, a plurality of stops 13, a handle 14, and a shroud or cover 50. The wheels 12 may be mounted independently of each other to the frame, or in other embodiments, the wheels may rotate together on an axle (not shown) that is rotatably mounted to the frame 60. The handle 14 serves as the structure to manipulate when moving the pressure washer 10.
The frame 60 may be formed from metal and may preferably be formed with hollow metal tubing for high suitable strength but limited weight and material requirements. As shown in the figures, the frame 60 includes a vertical rear section 62, a bottom section 63, and a top section 64. The rear section 62 includes two vertical posts 62a and a horizontal cross-member 62b (
The bottom section 63 includes two arms 63a, each extending from a respective one of the vertical posts 62a. The bottom section 63 additionally includes a front cross-member 63b that connects the two arms 63a and is at substantially the same height as the cross-member 62b of the rear section 62. Finally, the top section 64 includes two arms 64a that extend from one of the two vertical posts 62a of the rear section 62. The arms 64a extend substantially perpendicularly from the vertical posts 62a and curve slightly downward as they project toward the front end of the machine. The two arms 64a are connected at the front end with a cross-member 64b.
A mounting plate 65 may be attached to the cross-member 62b of the rear section and the cross-member 63b of the bottom section 63. The mounting plate 65 accepts and stabilizes the engine 40 above the mounting plate (and below the top section 64 of the frame 60) and includes an aperture (not shown) to operatively connect the pump 46 with the engine 40. The pump 46 extends from the engine 40 below the mounting plate 65a. As shown in
The shroud 50 is mounted to the frame 60 independently of the engine 40 and the pump 46. The shroud 50 is provided on the pressure washer 10 to at least partially enclose the engine 40 to provide a protective barrier against accidental contact with the engine 40 during operation that could lead to burns or other injuries. As shown in
The shroud 50 is mounted directly to the frame 60 and does not contact the engine 40 or any associated components. As can be understood by those of ordinary skill in the art, because there is no direct connection contact between the engine 40 and the shroud 50, there is no direct path for conduction heat transfer between the two components. This significantly reduces the amount of heat that can be transferred to the shroud 50, and accordingly reduces the maximum temperature of the shroud during pressure washer 10 operations.
The shroud 50 may be mounted to the frame 60 at multiple locations to increase the stability of the shroud 60. As best shown in
A dampener 62, such as a layer of rubber or other similar material, may be provided between the frame 60 and the shroud 50 at each mounting location. This dampener 62 attenuates or substantially prevents the transfer of heat from the frame 60 to the shroud 50 (and vice versa), and also substantially prevents the transfer of any vibrations that may be present in the frame 60 from transferring to the shroud 50 (and vice versa). Accordingly, because the dampeners 62 attenuate or substantially prevent the transfer of heat and vibrations from the frame to the shroud 50, the shroud 50 can be designed and manufactured with a broader range of shapes, sizes, and materials than would be possible if the shroud 50 reached higher temperatures during pressure washer 10 operation or if the shroud 50 was subject to vibrations of a larger magnitude.
As best understood with reference to
As best shown in
The shroud 50 may be formed from various materials. The shroud 50 may be formed from plastic and integrally mounted in a single piece. The shrouds 50 that are manufactured from plastic may be conveniently and inexpensively molded as a single component in the desired shape. As is known to those of ordinary skill in the art, plastic has a relatively low thermal conductivity. Additionally, plastic can be molded to be relatively elastic, which is useful for receptacles 56 that receive some of the pressure washer tools. For example, as shown in
In addition to providing a plurality of receptacles 56a, 56b, the shroud may include a plurality of vents, or louvers, 70 to allow air flow through the shroud 50 to interact with the engine 40. The vents 70 formed on the shroud 50 may be positioned to allow inlet and exhaust air to flow to and from the engine in conjunction with the combustion process. Additionally, vents 70 may be used to allow air flow past the engine 40 during operation (either by natural or forced air circulation) to remove heat by convection. As can be understood, the vents 70 can be integrally formed in the shroud 50 when formed as a molded plastic piece. Alternatively, the vents 70 can be formed in the shroud 50 after the initial formation of the shroud 50 in an independent step for shrouds 50 that are formed from metal or another similar material.
A second representative embodiment of the machine is shown in
The shroud 150 is formed from multiple pieces, a front member 151, right and left sides 152, 153, a top member 154, and a rear member 155. As shown in the exploded view of
As with the embodiment discussed above, the shroud 150 may include a plurality of structures 156 for receiving tools for use with the pressure washer 100. Specifically, the shroud may receive a spray gun 92 and a lance 94 as well as a plurality of nozzles 96. Additionally, the shroud 150 includes a plurality of vents 170 along the sides and top of the shroud 150 to allow air flow past the engine 140 (that is substantially enclosed within the shroud 150) for cooling as well as air flow for use with the combustion process.
The foregoing disclosure is the best mode devised by the inventors for practicing this invention. It is apparent, however, that apparatus incorporating modifications and variations will be obvious to one skilled in the art. Inasmuch as the foregoing disclosure is intended to enable one skilled in the pertinent art to practice the instant invention, it should not be construed to be limited thereby but should be construed to include aforementioned obvious variations and be limited only by the spirit and scope of the following claims.
It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention.
