Patent Publication Number: US-8539637-B2

Title: Harness for backpack blower

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 12/452,520, filed May 10, 2010, which claims the priority benefit of U.S. Provisional Patent Application Ser. No. 60/958,917 filed Jul. 10, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates generally to the field of lawn and garden tools and, more particularly, to a backpack mounted power tool with a harness that spaces the power tool apart from the operator. 
     2. Description of Related Art 
     Yard tools, such as blowers, brush cutters, chemical spreaders and other tools powered by small air-cooled internal combustion engines, are popular among professional grounds keepers as well as the common homeowner. As these tools can be heavy and bulky, it has been known to mount various components of the tool on a backpack frame so that the tool is carried on the back of an operator during work. For example, backpack blowers have been used in lawn and garden applications to enable an operator to direct a stream of high velocity air toward one or more objects to propel the objects along the ground. Such backpack blowers are capable of developing flow velocities and flow volumes greater than the capabilities of ordinary hand-held blowers. 
     One noticeable problem with many conventional backpack frames for power tools is they are bulky and uncomfortable to wear. Typical backpack-type frames are generally formed from a pipe material and have an L-shape with a pedestal that projects rearwardly to carry the tool. The heavy weight of the tool and the frame itself is a burden on the operator and makes it difficult for the operator to extend and move while using the tool. Additionally, the frame typically maintains the internal combustion engine in close proximity to the back of the operator. This increases the heat felt by the operator and can lead to discomfort. 
     SUMMARY OF THE INVENTION 
     The invention is directed to an improved backpack-type power tool configured to be carried on the back of an operator. The power tool includes a power tool housing at least partially encompassing an internal combustion engine and a harness on which the power tool housing is mounted. The harness has a pair of shoulder straps, a waist strap, and a panel connecting the shoulder straps and waist strap. The power tool housing is mounted on a frame having at least one arcuate tool-supporting member with an upper end proximate the shoulder straps and a lower end proximate the waist strap. The tool-supporting member is shaped along its vertical length such that a middle portion of the member arcs away from the panel such that there is an air-circulation space between the power tool housing and the panel. Desirably, the panel is a mesh fabric material. In one embodiment, the power tool is a blower and the housing has an air intake port facing the air-circulation space. This blower tool has two elongate tool-supporting members, namely an upper cross member and a lower cross member, and the air intake port is positioned such that it takes a suction between the two tool-supporting members. 
     These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems and methods according to this invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure, operation, and advantages of the presently disclosed embodiment of the invention will become apparent when consideration of the following description taken in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a backpack mounted power tool; 
         FIG. 2  is a perspective view of the harness of the backpack of  FIG. 1  with the housing of the power tool removed for clarity; 
         FIG. 3  is side view of the harness of  FIG. 2 ; and 
         FIG. 4  is view of an operator wearing the backpack mounted power tool of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the views of the drawings. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The invention will now be described in the following detailed description with reference to the drawings, wherein preferred embodiments are described in detail to enable practice of the invention. Although the invention is described with reference to these specific preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. But to the contrary, the invention includes numerous alternatives, modifications and equivalents as will become apparent from consideration of the following detailed description. 
     Turning now to the Figures,  FIG. 1  illustrates a backpack-mounted power tool  10  equipped with a harness  12  and an internal-combustion engine  14 . The harness  12  has left and right shoulder straps  16  that enable the power tool  10  to be carried on the back of the operator. The internal combustion engine  14  may be a conventional air cooled two-stroke or four-stroke engine disposed within a housing  18  and provides a power source for the tool  10 . In the illustrated embodiment, the power tool  10  is a centrifugal-type blower suitable for blowing fallen leaves, debris or the like. However, one skilled in the art will understand that the power tool  10  may be another back-pack mounted, engine-driven tool such as a brush cutter, line trimmer, chemical spreader or similar tool without departing from the scope of the invention. 
     As is known in the art, a centrifugal impeller (not shown) of the blower  10  is operationally connected to an output shaft (not shown) of the internal-combustion engine  14 , and is rotationally driven by the rotation of internal-combustion engine  14 . Air from around the housing  18  is sucked into a volute case  20  formed in the housing  18  through an air intake port by the rotation of the centrifugal impeller. The air is then discharged from an air discharging hose (not shown) in a high-speed airflow. As engine-driven centrifugal blowers are known in the art, additional specifics of the engine and volute related components of the blower  10  need not be described herein in additional detail. 
     Turning now to  FIG. 2 , the harness  12  has two shoulder straps  16  and a waist belt  24 . Desirably, the shoulder straps  16  and waist belt  24  are padded to minimize wearer discomfort. Male and female buckle members  26  are fixed at the two ends of the waist belt  24 . Shoulder straps  16  are individually adjusted by means known in the art to mount the blower  10  at the proper height for each operator. Similarly, the waist belt  24  is adjustable so as to fit around the waist of any operator. The operator places his arms through the shoulder straps  16  and secures the waist belt  24  by connecting the male and female buckle members  26 . The shoulder straps  16  and waist belt  24  may then be adjusted to fit the operator. 
     The harness  12  contains a frame  30  for receiving the housing  18  of the blower  10 . Two elongate blower-supporting members  32 , broadly tool supporting members, extend from a position near the top of harness  12  proximate the shoulder straps  16  to a position near the bottom of the harness  12  adjacent the waist belt  24 . Desirably, the blower-supporting members  32  are elongate bands having a width of between about 0.75 and 2.0 inches (1.9 and 5.1 cm) and a thickness of between 0.10 and 0.30 inches (0.25 and 0.8 cm) and are made of a stiff yet flexible material such as spring steel. Other suitable materials are aluminum, steel, fiberglass, carbon fiber, and the like. The housing  18  is attached to the blower-supporting members  32 . Suitable means to attach the housing  18  to the blower-supporting members  32  include the use of screws, rivets, or other fasteners (not shown). Alternately, the blower-mounting members  32  may pass through openings or slots formed in the housing  18 . However, one skilled in the art will understand that the housing  18  may be attached by other suitable means selected using sound engineering judgment. Desirably, the power tool housing  18  is mounted to the tool-supporting members  32  via vibration isolation members (not shown), such as a set of four rubber vibration isolators positioned between the vertical members  32  (two on each vertical member) and the housing  18 . 
     In the illustrated embodiment, the top of the blower-supporting members  32  connect to an upper cross member  34  that is also made of a rigid material. The upper cross member  34  extends laterally across a portion of the harness  12  between the shoulder straps  16  such that it lies across the wearer&#39;s upper back and shoulders. The lower ends of the blower-supporting members  32  connect to a lower cross member  36  that is also made of a rigid material. The lower cross member  36  also extends laterally across a portion of the harness  12  and has a generally arcuate shape such that the locations to which the blower-supporting members  32  connect are spaced from the waist belt  24  such that there exists a spatial separation between the lower ends of the blower-supporting members  32  and the wearer&#39;s back. A second generally flat lower cross member  38  attached to the waist belt  24  may join the arcuate lower cross member  36  to the waist belt  24 . The blower-supporting members  32  and the upper cross member  34  and lower cross member  36 ,  38  are provided with metal rivets, grommets or other suitable fasteners  40  to fasten the components at their junctions. Desirably, the blower-support members  32  are angled slightly such that the distance between the members  32  near the lower cross member  36  is greater than the distance between the members  32  near the upper cross member  34  to aid in the stability of the harness  12 . 
     The expanse between the shoulder straps  16  and the waist belt  24  is bridged by ribbing and/or a fabric layer, broadly a panel  44 , which connects the shoulder straps  16  and waist belt  24  and thus the upper and lower cross members  34 ,  36 . In one embodiment, expanse between the shoulder straps  16  and the waist belt  24  is bridged by an air-permeable, open mesh fabric panel  44 . Desirably, the frame  30  holds the panel  44  in a substantially constant tension. This panel  44  is adapted to be positioned adjacent the back of a wearer of the blower  10  and desirably permits air circulation thereby reducing overheating and discomfort that otherwise might result from wearing the harness  12 . One skilled in the art will recognize that the panel  44  may have variations in its dimension and also have cutout portions without departing from the scope of the invention. 
     As best seen in  FIG. 3 , it is an important feature of the invention that the blower-supporting members  32  be deformed along their vertical length such that the center portions of the blower-supporting members  32  arc away from the panel  44  and thus the wearer&#39;s back. The blower-supporting members  32  are shown as continuously curving arcuate bands, however one skilled in the art will appreciate that bands with a multitude of discrete bends formed therein so that the overall shape of the bands has a substantially arcuate shape are also contemplated and do not depart from the scope of the invention. In one embodiment, a deforming tension force is applied along the length of the blower-supporting members  32  by means of the panel  44  connecting the upper and lower cross members  34 ,  36 . Alternately, the blower-supporting members  32  may be made of a shape-retaining material such that the members  32  are formed having an arcuate shape. When the curvature is thus maintained in the blower-supporting members  32 , a zone of spatial separation or air circulation space S is established between the housing  18  and the panel  44  to ensure free air circulation between the blower  10  itself and the wearer&#39;s back B as seen in  FIG. 4 . Desirably, an air intake port  46  in the housing  18  of the blower  10  is positioned facing the air intake space S to increase the circulation of air between the wearer&#39;s back B and the housing  18  of the blower  10 . Additionally, the air intake port  46  may be positioned in the center of the blower volute  20  such that the suction is taken in between the two blower-supporting members  32 . The arcuate blower-supporting members  32  are shaped such that the air intake space S between the housing  18  of the blower  10  and the panel  44  of the harness adjacent the back B of the wearer desirably has a distance of at least about 2.0 inches and more desirably at least 3.0 inches. 
     While this invention has been described in conjunction with the specific embodiments described above, it is evident that many alternatives, combinations, modifications and variations are apparent to those skilled in the art. Accordingly, the preferred embodiments of this invention, as set forth above are intended to be illustrative only, and not in a limiting sense. Various changes can be made without departing from the spirit and scope of this invention.