Cutlery – Cutting tools – Saw
Reexamination Certificate
2000-07-28
2003-05-27
Watts, Douglas D. (Department: 3724)
Cutlery
Cutting tools
Saw
C030SDIG001
Reexamination Certificate
active
06568089
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of power tools and in particular to the field of hand-held reciprocating saws.
2. Description of Related Art
Reciprocating saws are often used by tradesmen, such as carpenters, plumbers and electricians, for making rough cuts in wood or other hard materials. Manually sawing these materials would be a difficult and time consuming undertaking. Further, many applications require a saw to be used in a confined area where it would be even more difficult to move a saw blade manually back and forth. Consequently, reciprocating saws relieve the user from having to generate the reciprocating action of the saw blade. The motive force in a reciprocating saw is conventionally provided by a motor instead of by the user. The motor typically drives a drive assembly, which in turn reciprocates a saw blade or other tool.
Known reciprocating saws suffer from several drawbacks. In some known reciprocating saws, the motor, drive assembly, reciprocating shaft and blade are each longitudinally aligned along a common axis, creating a tool having a length at least as long as the combined longitudinal length of the motor, drive assembly and reciprocating shaft. This configuration causes the saw to be longer than necessary, which can render impossible, or at best complicate, some cuts to be performed in a limited space. A long saw is also generally awkward to use and unwieldy, and is difficult to store when not in use. Furthermore, the length of the saw can prevent the saw from balancing and standing upright on a flat surface such as a tradesman's scaffolding, a ladder, or a retail shelf.
Furthermore, in some known reciprocating saws, the housing for the saw assembly is unnecessarily complicated and expensive. Openings in the housings of reciprocating saws to facilitate cooling the motor also allow saw dust and other debris to enter into the housing and contaminate the components within the housing. Thus, separately sealed gear box housings are used to enclose some of the working components of the saw, protecting them from debris.
One known arrangement, such as that disclosed in U.S. Pat. No. Re. 35,258, has a separate gear box outside of and attached to the exterior of the housing which surrounds the motor. Having the separate gear box attached to the exterior of the motor housing presents several drawbacks.
First, the exterior surface of the gear box can be expensive to manufacture. For aesthetic and comfort reasons, the external surfaces of the saw are generally smooth and polished. Since, with this design, the exterior surface of the gear box is also an external surface of the saw, at least a portion of the exterior surface is sometimes manufactured to be smooth. Manufacturing a smooth gear box can increase the cost of the saw.
Second, an insulating cover is sometimes required to be fitted around the exterior surface of the gear box in this design. The insulating cover can protect the user from electrical shock if a live electrical wire is cut with the saw. Also, since the gear box can become very hot during prolonged use of the saw, an insulating covering is sometimes necessary to insulate a user's hands from the heat of the gear box. Applying an insulating covering to the gearbox, while potentially eliminating the cost of producing a smooth gear box, is nonetheless still an added expense.
Third, with the design of the '258 patent, the external gear box must be securely attached to the exterior of the motor housing. This can add to the cost of manufacturing the saw.
Furthermore, reciprocating saws create vibration. U.S. Pat. No. Re. 35,258 attempts to address this problem. It discloses a reciprocating saw having a counterbalanced reciprocating mechanism. The counterbalance in the '258 Patent purportedly uses the momentum of a counterbalance to reduce the vibration caused by the combined momentum of a reciprocating shaft and saw blade. While such a configuration may diminish undesirable vibration, it does not provide a configuration as compact and convenient as possible.
These and other drawbacks of known reciprocating saws are overcome by the invention as disclosed herein in conjunction with the preferred embodiments.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a compact reciprocating saw which has a base allowing the tool to stand upright on a flat surface independently of additional support mechanisms.
If is a further object of the invention to provide a reciprocating saw which is compact.
If is a further object of the invention to provide a reciprocating saw which is cordless and battery powered.
It is a further object of the invention to provide a simple and inexpensive housing for protecting the working components of the saw from damage that may result from debris generated during operation of the tool and to prevent lubricating agents from escaping from the working components of the tool.
It is a further object of the invention to provide a reciprocating saw that has reduced vibration.
These and other objects, features and advantages of the invention are achieved by providing a power operated reciprocating saw comprising a housing including a handle portion, a reciprocating shaft adapted for reciprocal movement along a longitudinal axis, and adapted to support a working tool, a motor mounted inside the housing, a drive assembly which is driven by the motor and drives the reciprocating shaft in a reciprocal motion, a base connected to the housing upon which the reciprocating tool may rest against a surface, wherein when the power operated reciprocating tool is resting on the base, the saw is capable of upright independent standing.
The objects of the present invention are also achieved by a power operated reciprocating tool comprising a reciprocating shaft adapted for reciprocal movement along a longitudinal axis, and adapted to support a working tool, a motor, a drive assembly operatively connected with the motor for driving the reciprocating shaft, a sealed drive housing enclosing at least a portion of the reciprocating shaft and at least a portion of the drive assembly, the sealed drive housing adapted to seal grease inside of the sealed drive housing, and a two-piece housing surrounding the sealed drive housing and the motor.
The objects of the present invention are also achieved by a battery operated reciprocating saw comprising a reciprocating shaft adapted for reciprocal movement along a longitudinal axis, and adapted to support a working tool, a housing, a motor disposed inside the housing, a drive assembly operatively connecting the motor and the reciprocating shaft, a battery selectively attachable to the housing, and wherein a rotational axis of the motor is at an angle of ninety degrees with respect to the longitudinal axis of the reciprocating shaft.
These and other objects, features and advantages of the preferred embodiments will be apparent through the detailed description of the preferred embodiments in conjunction with the drawings.
REFERENCES:
patent: D194736 (1963-02-01), Godfrey et al.
patent: D214987 (1969-08-01), Ballone et al.
patent: 3496972 (1970-02-01), Rees
patent: 3757194 (1973-09-01), Weber et al.
patent: 4353425 (1982-10-01), Simpson
patent: 5006740 (1991-04-01), Palm
patent: 5398417 (1995-03-01), Quirijnen et al.
patent: 5575071 (1996-11-01), Phillips et al.
patent: 5596810 (1997-01-01), Neubert et al.
patent: 6263979 (2001-07-01), Dyke et al.
patent: 1-281880 (1989-11-01), None
Advertisement of DeWalt High Performance Industrial Tools & Accessories, 24V Cordless tools, Model No. DW004K (SDS Rotary Hammer Kit); Model No. DW006K (Drill/Hammerdrill Kit); Model No. DW007K (Circular Saw Kit); and Model No. DW008K (Reciprocating Saw Kit), 2000 Catalog.
Advertisement of Milwaukee Heavy-Duty Electric Tools, Catalog 2000, 18 Volt Power-Plus Sawzall & Sawzall Combo Kit, Model No. 6515-20 (Tools Only); Model No. 6515-21 (Battery Pack, Charger, 2-Blade Pack, and Steel Carrying Case); and Model No. 6515-22 (Two Battery Packs, Charger, 2-
Clowers Earl Roger
Etter Mark Alan
Lagaly Michael Anthony
Mooty Thomas Arnold
Nichols, Jr. James Pierce
Hunton & Williams
Porter-Cable/Delta
Watts Douglas D.
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