Patent Application
20060260458
1. Field of the Invention
The present invention is directed to a coping saw. More specifically, the present invention teaches a one-handed and ergonomically configured motorized coping saw exhibiting a looped cutting band driven by a planetary gear arrangement, and such as is particularly useful in cutting most available types of crown and baseboard moldings.
2. Description of the Prior Art
The process of coping has traditionally been completed with a coping saw. A traditional saw of this construction typically includes an elongated blade secured at opposite ends between a substantially “U” shaped frame defining a deep cutting throat, a handle extending from an end of the frame and which is capable of being grasped by a user for influencing reciprocating motion of the blade across a desired cutting workpiece surface (such as again in particular crown or baseboard moldings and the like).
Other attempts have been made to incorporate a spiral driven saw blade into a powered mechanism for providing faster and more effort-free cutting of a workpiece. A first example of this is set forth in U.S. Pat. No. 5,220,729, issued to Gallant, and which teaches a handheld power saw having a main housing and two guide housings telescopically interactive with the main housing and having facing open distal extremities. A motor and associated drive pulley are associated with the main housing. Paired idle and alignment rollers are disposed within the guide housings and an endless abrasive wire rope is centrally disposed within the main and guide housings in contact with the drive pulley and paired rollers. The region of the wire rope extending between the facing distal extremities of the guide housings is employed to cut a workpiece.
Nikisch, U.S. Pat. No. 3,621,894, teaches a spiral blade saw used as a hand or bench model and including a drive means for carrying a continuously winding spiral blade. As best shown in the opened view of
Cortez, U.S. Pat. No. 4,193,192, teaches a band saw device including a plurality of rollers defining a saw blade path, which is continuously arcuate except for a straight cutting section corresponding to a side opening formed in a body of the band saw device. A friction belt drive with associated guide rollers provides the motive force for the saw blade. Tension on the saw blade is adjusted by means of a pivotal roller carriage which is adjustable with respect to the main frame of the band saw with the roller carriage being horizontally adjustable with respect to the main frame.
A further series of powered saw designs, each of these utilizing a generally conventional coping saw configuration, are further illustrated in such references as Ward, U.S. Pat. No. 5,924,209 (WO 99/17900); Halsey, U.S. Pat. No. 5,388,334; and Roberts, U.S. Pat. No. 6,401,346. Additional examples of translating or cable saw assemblies are shown in Gates, U.S. Pat. No. 3,958,332 and Lofgren, U.S. Pat. No. 1,303,809. Another reference of note is Flagg, U.S. Pat. No. 6,282,793, and which teaches a coping saw attachment for a handheld power jig saw.
The present invention is an ergonomically configured and one-handed powered coping saw for ease of use in performing a ripping operation on a vast majority of existing molding types in single pass fashion. The saw includes a three-dimensional shaped body with a hand grip and a base defining multi-sided exterior configuration.
An electric motor is supported upon a mounting plate and installed within the housing. The motor is positioned within the body at a height and location approximate a center point defined by the cutting band and such that the motor sits above the gears and cutting band.
A gear drive system extends from an exposed face of the mounting plate. In a preferred embodiment, the gear drive system further includes a planetary drive system for communicating a power output of the motor to a plurality of perimeter defined gears.
A continuous cutting band is supported upon perimeter defined gears associated with the gear drive system, such that the band projects from a plurality of arcuately configured exterior surfaces associated with the body. A cutting zone is established at each projecting location of the band to perform a ripping operation on a workpiece positioned within a selected cutting zone. The blade direction of travel can further be made reversible by adding a “reversible switch” to the assembly. The coping saw may further incorporate an abrasive wire rope, such as which is suitable for cutting tile.
Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:
Referring now to the environmental view of
The saw 10 includes a body defined by an outer housing and including an uppermost palm-shaped grip 14, this typically shaped in ergonomic fashion and constructed of a non-slip rubber or other suitable material providing for ease of use by individuals with differently sized hands. Extending in overhead fashion above the palm grip 14 is an adjustable strap 16, connected at opposite ends 18 and 20 to underside locations of the palm grip 14 approximate to an intermediate extending annular portion 22 of the housing. A power cord 24 extends from the grip 14 in a fashion that it does not interfere with the subsequent manipulation and ripping operations associated with the saw 10. As will also be described subsequently, other forms of power input, such as portable batteries or power packs, can be utilized with the saw 10.
The housing further includes a base integrally connected to the annular extending portion 22, the base exhibiting a specified depth and including a plurality of four outwardly radially and arcuate extending portions 26, 28, 30 and 32. An electric motor, such as an AC motor (or DC motor in the instance of a battery/power pack) as is illustrated at 34 in
A variable speed power switch is illustrated at 35 (see
Secured to an opposite surface of the motor supported mounting plate is a planetary drive gear system and which communicates a rotatable output of the motor 34 to a closed and continuously driven cutting band 42. As best illustrated with reference to
A ring-shaped gear is exhibited at 52 and includes both inner and outer toothed perimeters. The ring 52 encircles and is meshingly engaged by each of the first plurality of gears 46, 48 and 50 in order to rotate in a specified direction. An exterior surface of the ring-shaped gear 52 meshingly engages each of a second plurality of driven gears 54, 56 and 58 arranged at outer circumferential locations about the ring-shaped gear 52. The gears 54, 56 and 58 are pin mounted to apertures in the motor supporting plate, and such as shown at 60 and 62 in
A band support gear is meshingly engaged to each of the second driven gears and is represented at 64, 66 and 68, corresponding to gears 54, 56 and 58, and associated with outermost locations of the arcuate extending portions 26, 28 and 32 of the base mounting surface of the coping saw body. Additional outermost apertures, shown representatively at 70, 71 and 72 in
Each of the three outermost driven gears 64, 66 and 68 operate as a band supporting gear and in order to support the cutting band 42 in extending fashion about the lower periphery of the body. In particular, and as is best illustrated in the exploded view of
A fourth outermost located roller, see at 73 and which corresponds to arcuate portion 28 of the body, is arranged in freely rotatable fashion (as opposed to the other three gear driven supports 64, 66 and 68). The roller 73 includes a cutting band support recess for securing the cutting band 42 at a fourth perimeter extending location and such that the said cutting band exhibits a substantially four-sided configuration about the gear system and is supported in friction fit fashion within the band support gears.
The freely rotatable band support roller 73 includes a quick release lever 74, which permits the roller 73 to be translated between an outermost displaced and band tensioning position and an inwardly displaced and band relaxed position. This is accomplished by a support pin 77 associated with the free rotating roller 73 and which seats in translating fashion along a slot 79 defined in the motor mounted support surface associated with the roller.
The lever 74, as shown in
A bottom cap is provided and includes four arcuate extending portions 76, 78, 80 and 82 and which correspond in mating alignment with the likewise arcuate portions associated with the housing base and attachable base plate supporting both the motor 34 and planetary gear drive system. The bottom cap corresponds in shape and configuration with the base surface and seats the mounting plate in sandwiched fashion therebetween.
The bottom cap further includes a plurality of depthwise extending and arcuately configured sidewalls, a plurality of gaps existing between the sidewalls and defining pathways for permitting the blade to traverse in and out of the assembled housing. In particular, and referencing again
In this fashion, the cutting band 42 defines a substantially four-sided configuration about the gear system and creates a plurality of four cutting zones, represented generally at 94, 96, 98 and 100 in
As is again illustrated in
Having described our invention, other and additional preferred embodiments will become apparent to those skilled in the art. Specifically, the planetary gear arrangement can be redesigned with other possible arrangements of driven or spur gears. Also, it is envisioned that the drive arrangement for the cutting band can be redesigned, along with the body of the tool, and in order to achieve a triangular or other multisided configuration.
