Patent Application
20070220702
1. Field of the Invention
The present invention relates to devices and methods for blowing debris and other unwanted materials from an area. More specifically, the present invention concerns a walk-behind blower having a plurality of impeller blades mounted around a periphery of a rotating support structure rather than on a rotating central shaft, and having an independent, wrap-around protective frame cage which provides both a stronger mounting point for a front wheel and skid protection for a housing.
2. Background of the Invention
Blowers are used for blowing debris and other unwanted materials in order to clear an area. As such, they typically include an engine driving a plurality of impeller blades for generating an air flow. The engine is mounted on a wheeled frame, and the impeller blades are located within a housing to both better direct the flow of air and prevent injurious or damaging contact with the moving blades.
Blowers are typically provided with impeller blades presenting relatively simple, flat, paddle-like shapes. The bases of the blades are secured to a central shaft coupled with the engine, and the free ends of the blades extend radially outward therefrom. This requires that the central shaft or other structure for mounting the impeller blades be located approximately centered within the blower's air intake, which can diminish or disrupt the flow of air into and through the blower.
Additionally, when blowers are provided with a front wheel, the front wheel is typically coupled directly to the housing. Being constructed of relatively thin material such as plastic or aluminum, the housing is relatively weak and prone to damage from impacts and scrapes. Shocks to the front wheel, which occur, for example, when a blower is dropped from a truck or strikes an obstacle, are transmitted directly to the housing, often resulting in damage, such as cracking or denting, to the housing, which may reduce blower efficiency. Furthermore, when the blower tips over or brushes against a structure, such as a curb, wall, or fence, the housing can be scraped or otherwise damaged due to the contact.
The present invention provides a blower for blowing debris and other unwanted materials in order to clear an area, comprising the feature of a plurality of impeller blades mounted around a periphery of a rotating support structure rather than on a rotating central shaft, thereby improving air flow into and through a housing, and the feature of an independent, wrap-around protective frame cage which provides both a stronger mounting point for a front wheel and skid protection, thereby providing greater protection to the housing.
The blower broadly comprises an engine, the housing, an impeller assembly, the independent, wrap-around frame cage, at least one rear wheel, and at least the one front wheel. The impeller assembly creates the air flow and is located substantially within the housing. The impeller assembly includes a rear support structure, a front support structure, and the plurality of impeller blades. The support structures are substantially disk-shaped, or circular, with a central area and a peripheral area surrounding the central area. In one embodiment the support structures are substantially planar; in another embodiment one or both are substantially conical in cross-section. The plurality of impeller blades are mounted spaced apart on the peripheral area, such that the impeller blades are supported by and between the rear and front support structures. Each impeller blade presents a substantially straight portion and a substantially curved portion, with the curved portion being substantially concave in a direction of rotation. Each impeller blade is mounted to the rear support structure at an angle of approximately between 20 degrees and 30 degrees relative to a line originating at a center of the substantially disk-shaped rear support structure and extending radially outward therefrom.
The independent, wrap-around frame cage extends substantially around a front portion of the housing and couples with the front wheel. More specifically, the frame cage extends around a first side of a lower portion of the housing, extends around a front portion of the housing below an intake opening, and then returns around a second side of the lower portion of the housing, without extending across the intake opening. The front wheel is located substantially in front of and below the housing.
These and other novel features of the present invention are described in more detail in the section titled DETAILED DESCRIPTION OF THE PRESENT INVENTION, below.
A preferred embodiment of the present invention is described in detail below with reference to the attached drawing figures, wherein:
With reference to the figures, a walk-behind blower 10 is herein described, shown, and otherwise disclosed in accordance with a preferred embodiment of the present invention. Broadly, the blower 10 is useful for blowing debris and other unwanted materials in order to clear an area, and comprises the feature of a plurality of impeller blades mounted around a periphery of a rotating support structure rather than on a rotating central shaft, thereby improving air flow into and through a housing, and the feature of an independent, wrap-around protective cage which provides both a stronger mounting point for a front wheel and skid protection, thereby providing greater protection to the housing.
Referring particularly to
The housing 14 both contains and directs a flow of air within the blower 10 and prevents injurious or damaging contact with the moving impeller assembly 16. In one embodiment, the housing 14 takes the form of a flattened but otherwise substantially spherical shell with an axis passing through the flattened ends oriented substantially horizontally. A first one of the flattened ends is oriented substantially rearwardly and presents an opening for receiving a transfer member which carries the driving force provided by the engine 12. A second one of the flattened ends is oriented substantially forwardly and presents an intake opening 24 for receiving air from the ambient environment. The intake opening 24 is typically covered by a safety shield which has been removed in the drawings in order to better show other components of the blower 10. A spiral duct 26 extends at least partly around a perimeter of the flattened spherical shell and terminates in an exhaust opening 28. The spiral duct 26 receives the air flow produced by the impeller assembly 16 and directs it, through a nozzle associated with the exhaust opening 28, outwardly. In one embodiment, the housing 14 is constructed from a lightweight material, such as plastic or aluminum, or combination of materials.
Referring also to
In one embodiment, the support structures 30,32 are substantially disk-shaped, and the impeller blades 34 are mounted spaced evenly apart around a peripheral portion of the support structures 30,32, leaving a central area 36 of the impeller assembly 16 substantially unobstructed for receiving air through the intake opening 24. The support structures 30,32 each present a substantially flat mounting surface. In one embodiment, one or both of the support structures 30,32 are substantially planar; in another embodiment, one or both of the support structures 30,32 are substantially conical in cross-section, with a slope of approximately between 30 degrees and 40 degrees. In one embodiment, the mounting surface of either or both of the support structures presents a coupling mechanism, such as, for example, a groove 38 or opening 40, for receiving or otherwise cooperating with a portion of each impeller blade 34 and thereby facilitate securely mounting the impeller blade 34 to the mounting surface. A central area 42 of the rear support structure 30 is coupled, as by, e.g., bolts, with the transfer member carrying the driving force provided by the engine 12, such that rotation of the transfer member results in rotation of the impeller assembly 16. A central area of the front support structure presents an opening 44 corresponding to the intake opening 24 of the housing 14 for receiving ambient air into the housing 14 to be acted upon by the impeller assembly 16.
In one embodiment, each impeller blade 34 presents a substantially straight portion 48 and a substantially curved, or arcuate, portion 50. As best seen in
The inward portions of the impeller blades 34 engage the ambient air and generate a large portion or all of the air acceleration and resulting blowing effect, which is in contrast to conventional configurations in which the outboard portions generate a large portion or all of the blowing effect. One advantage of the impeller blade configuration of the present invention is a reduction in vibration of the blower 10.
In one embodiment, each impeller blade 34 presents one or more projections 52 along an edge which is mounted to the mounting surface of the front support structure 32, wherein the projections 52 cooperate with the aforementioned openings 40 in the mounting surface to more securely mount the impeller blade 34 thereto.
In one embodiment, the impeller blade 34 is substantially perpendicular to the mounting surfaces of the support structures 30,32. In another embodiment, the impeller blade 34 intersects the mounting surfaces 30,32 at an angle that is other than substantially perpendicular. Furthermore, in one embodiment the impeller blade 34 has substantially consistent height, while in another embodiment the impeller blade 34 slopes between a maximum height at one end, either inward or outward, to a minimum height at the opposite end. In one embodiment, best seen in
The scale of the support structures 30,32 and the impeller blades 34, as well as the overall device 10 itself, will depend upon a number of considerations, including, for example, the particular contemplated application. In one contemplated application, for example, the substantially disk-shaped support structures 30,32 each have a radius of approximately between 16 inches and 18 inches; there are approximately between 14 and 16 impeller blades 34; and each impeller blade 34 has a length of approximately between 4 inches and 5 inches (with the flat portion 48 being approximately one-half the length), a maximum height of approximately between 4 inches and 4.5 inches, and a minimum height of approximately between 2.5 inches and 3 inches (i.e., a slope of approximately between a maximum of 44% and a minimum of 25%). Again, however, these dimensions may vary for other applications.
The independent, wrap-around frame cage 18 wraps, or extends, around at least a lower portion of the housing 14 to protect the housing 14 from scrapes or other damage, such as might otherwise occur if the blower 10 tips or brushes against a structure, such as, for example, a curb, wall, or fence. The wrap-around frame cage 18 is “independent” in the sense that it is distinct from and does not rely on the housing 14 for structural support for the front wheel 22. In one embodiment, the wrap-around frame cage 18 extends around one side of the lower portion of the housing 14, extends around the front of the housing 14 below the intake opening 24, and then returns substantially identically around the other side of the lower portion of the housing 14. The frame cage 18 may dip down along the sides to protect the lower portion of the housing 14 and rise up in the front to provide sufficient clearance for the front wheel 22, as described below. The wrap-around frame cage 18 does not extend across or otherwise obstruct the intake opening 24 in the housing 14 through which air is received. In one embodiment, the wrap-around frame cage 18 is substantially tubular in cross-section and constructed of a lightweight metal or other suitable material or combination of materials.
The one or more rear wheels 20 support and facilitate moving the blower 10. In one embodiment, there are two rear wheels 20, located substantially directly below the engine 12, spaced apart and connected by an axle.
The front wheel 22 supports and facilitates moving and steering the blower 10. The front wheel 22 is mounted to the wrap-around frame cage 18 rather than the housing 14 so that if the blower 10 is, for example, dropped from a truck or strikes an obstacle, the resulting physical shock is transmitted to the wrap-around frame cage 18 rather than to the housing 14. Furthermore, by coupling the wrap-around frame cage 18 with the front wheel 22, the protective frame cage 18 is substantially more rigid and stable than if it were not so coupled, i.e., secured at one end and free-floating at the other. In one embodiment, there is a single front wheel 22, located substantially in front of and below the housing 14, and pivotably mounted to the wrap-around frame cage 18 at a location where the frame cage 18 extends around the forward area of the housing 14. In another embodiment there are two or more front wheels, each being pivotably mounting in substantially the same manner.
In exemplary but non-limiting use and operation, the blower 10 may function and be used as follows. The engine 12 provides the rotational driving force which is carried by the transfer member to the rear support structure 30 of the impeller assembly 16. The driving force causes the impeller assembly 16 to rotate within the housing 14. The moving impeller blades 34, supported between the front and rear support structures 30,32, receive air via the intake opening 24 in the housing 14 and the corresponding opening 44 in the front support structure 32, and act upon the received air to create the air flow. As mentioned, the advantageous configuration of the impeller assembly 16 of the present invention, particularly the feature of using the inward rather than the outward portions of the impeller blades 34 to generate the air flow, avoids using a conventional central shaft which would obstruct the air flow. The air flow travels through the spiral duct 26 and exits the exhaust opening 28.
When it is desired to move the blower 10, the blower 10 is pushed to cause the rear and front wheels 20,22 to roll. When it is desired to steer the blower 10, the blower 10 is urged in such a manner as to cause the front wheel 22 to pivot in the desired direction. During such movement, if the blower 10 approaches an obstacle too closely, the wrap-around frame cage 18 advantageously protects the housing 14 from damaging contact with the obstacle. And if the front wheel 22 strikes an obstacle, the wrap-around frame cage 18, rather than the housing 14, advantageously absorbs the resulting shock.
Referring to
Though described and shown herein as being configured for walk-behind operation, it will be appreciated that the features of the present invention could be incorporated into a riding blower as well.
Although the invention has been described with reference to the preferred embodiment illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.
