Patent Application
20080235955
The present invention relates generally to hand tools and hand tool handles, and more specifically to jab saws for use in generally cutting soft materials such as wallboard.
Jab saws, which are available in various sizes, are used to manually cut shapes into wallboard and various other building panels including but not limited to wood. When using the jab saw, the shape to be cut is usually outlined onto the building panel. Next, the blade is aligned generally perpendicular to the panel surface. Then, the blade is pushed into the surface. A flat end on the back of handle is often provided as a striking area for the hand when additional force is required to coerce the plunge. Thumb and finger guards are also sometimes provided on the front of the handle for hand protection. After making the initial plunge cut, push and pull strokes are used to move the blade back and forth while simultaneously applying a lateral force to the handle to guide the path of the blade along the desired route.
Conventional jab saw handles are often heavy, bulky, difficult to grip and tiring to use over an extended period of time. Additionally, jab saws are generally either made with the handle directly molded to the blade or with the handle assembled to the blade prior to shipment of the saw. As an assembled jab saw requires greater packaging space than a disassembled saw, shipping costs are greater for assembled saws.
Consequently, there is a need for an improved jab saw that provides a light weight, strong gripping handle, and allows for the jab saw to be assembled after shipment, or remote from the point of manufacture.
The above-identified needs are met or exceeded by the present jab saw. To facilitate remote assembly, the present jab saw handle provides access to an internal fastening location so that the jab saw may be assembled after shipment and the assembly point of the blade to the handle is concealed post assembly. This feature addresses manufacturers' need to make efficient use of shipping space. Since homogenous parts can be packed more compactly, a container of only blades or only handles may be shipped at a lower cost and assembled at a remote location. In addition, the internal fastening location is concealable so that a user holding the handle will not be discomforted by the fastening location. Also, to increase control and grip, the present jab saw has an ergonomically shaped and soft gripping handle. Moreover, the handle is partially hollowed and provided with structural ribbing to provide a light yet sturdy handle.
More specifically, a jab saw includes a blade having a piercing end and a handle end, separated by a cutting edge. A handle is configured for receiving the handle end and providing access to an internal fastening location after construction.
In another embodiment, a jab saw includes a blade having a piercing end and a handle end separated by a cutting edge, the handle end having at least one fastener opening. A handle includes first and second housing halves configured for enclosing the handle end. The first and second housing halves include an exterior surface defining at least one recess providing access to an internal fastening location. The first and second housing halves define a cavity to accommodate the handle end, the at least one of first and second housing halves including at least one fastener constructed and arranged for entering through the internal fastening location and for engaging a corresponding fastener opening through the cavity for securing the handle to the handle end. At least one insert is configured for engaging a corresponding recess.
Referring now to
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The cutting edge 20 is located between the piercing end 16 and the handle end 18, with generally linearly arranged teeth 30 projecting generally normally to the top edge 22. Preferably, there are seven teeth 30 per inch along the cutting edge 20. It has been found that seven teeth 30 per inch allows for a fast, aggressive cut in softer materials such as wallboard. However, it is contemplated to have more teeth 30 per inch if the present blade 12 is needed to make a finer, slower cut for denser materials such as plastic. Also, a lower tooth density is contemplated for making coarse cuts as is known in the art. In the preferred tooth configuration, each tooth 30 has only one side sharpened, and teeth having edges sharpened on the same side are arranged alternately. Such a pattern has been found to yield a fast, aggressive cut but various other tooth patterns may be substituted. Additionally, the teeth 30 are relatively short, and preferably generally do not extend past an end portion 32 of the handle end 18, which facilitates cutting small circles and tight radii in a surface.
In the preferred saw 10, the handle end 18 has three openings; however the number of such openings may vary to suit the application. An optional center opening 34, located closest to the cutting edge 20, may be used for securing or immobilizing the blade 12 during handle installation; however it is more preferable to employ the opening as a fixture point in packaging the jab saw 10 or the blade.
At least one and preferably two fastener openings 36 (
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A plurality of generally elliptical protrusions 52 on a first side of the handle 14 corresponding to the upper blade edge or top edge 22, are preferably linearly arranged according to size, provide increased grip for the palm of the hand. A pair of hump-like projections 54 on the opposing side of the handle 14 nestle the fingers along the exterior surface 38. These features combine to provide a more positive grip between a user's hand and the exterior surface 38. As a result, the user is able to exert greater control and apply increased force over the handle 14 without the hand slipping. Other shapes for the handle 14 are contemplated, including but not limited to different numbers and types of the protrusions 52 and the hump-like projections 54. Between the exterior surface 38 and the interior surface 40 is a handle core 42 preferably made of a hard plastic material such as polypropylene with approximately 20% glass fiber, but various other materials exhibiting similar properties are contemplated.
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In the preferred embodiment, only one of the first and second housing halves, which are asymmetrical, will be provided with the at least one recess 64. Alternatively, both asymmetrical housing halves 56, 58 may have recesses 64 but only one of the recesses may allow access to the internal fastening location 50 (
In the present jab saw 10, the recess 64 is located on the first housing half 56. The recess 64 is elliptical in shape and positioned approximately axially along the exterior surface 38 of the first housing half 56. The recess 64 is also dimensioned to have sufficient depth to allow access to the internal fastening location 50 and for fasteners 66 to be secured to fastener openings 36 in the blade 12.
Referring to
Additionally, there is at least one insert 72 configured for engaging the corresponding recess 64 with a tight friction fit. In the present jab saw 10, the recess 64 is of sufficient depth to allow the inserted fasteners 66 to be covered by the insert 72. The insert 72 is dimensioned to complement the shape of the recess 64 and have a circumferential lip 74 that is generally flush with the exterior surface 38 so that a user is not discomforted from holding the handle 14. Further details of the construction of the insert are provided in commonly assigned copending U.S. patent application Ser. No. 11/328,530 filed Jan. 10, 2006, which is incorporated by reference.
To additionally secure the insert 74 in the recess 64, at least one and preferably a pair of lugs 76 are provided on the bottom of the insert to matingly engage holes 78 inside the recess. It will be understood that the holes 78 may be provided to the insert 72 and the lugs 76 to the recess 64, and other fastening techniques for securing the insert to the recess are contemplated. Thus, the insert 72 is designed and configured to not only provide a safe and comfortable grip for the user but also to conceal the internal fastening location 50 after the blade 12 has been secured to the handle 14.
Returning to
The second end 48 of the handle 14 is oriented to point away from the piercing end 16 of the blade 12 and is provided with a striking area 84. The striking area 84 is generally flat and can be stricken with the palm of the hand or a similar object to help push the jab saw 10 through a receiving wallboard panel or the like.
Referring now to
In operation, when using the jab saw 10, a user first outlines the shape sought to be cut into the material. Next, the user aligns the blade 12 of the jab saw 14 generally perpendicular to the surface. Then, the user pushes the blade 12 into the surface, hitting the striking area 84 if additional force is needed. After making the initial plunge cut, the user applies push and pull strokes to move the blade 12 back and forth while simultaneously applying a lateral force to the handle 14 so as to guide the path of the blade 12 along the desired route.
While a particular embodiment of the present jab saw has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
