Cutlery – Cutting tools – Saw
Reexamination Certificate
1999-07-22
2001-08-14
Watts, Douglas D. (Department: 3724)
Cutlery
Cutting tools
Saw
C030S392000
Reexamination Certificate
active
06272757
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power tool having a reciprocating, and sometimes oscillating and sometime adjustable stroke length, saw blade holder. More particularly, the present invention relates to an adjustable and removable guide shoe for such a power tool.
2. Scope of the Prior Art
Reciprocating saws are provided with a shoe which permits the operator to position the saw relative the work being cut. As is known to those who are experienced in using such tools, for a particular application there is an optimum position for the shoe. Adjustment of the shoe makes plunge and pocket cuts easier and extends the blade life by cutting with different areas of the blade. Sometimes, it is also desired to remove the shoe for use of the saw in awkward positions such as comers and the like.
A typical shoe support is secured into position with adjusting screws. These screws pass through slots in the shoe support and thread into the front end of the gear housing clamping the support and shoe in the desired position. Adjustment of the shoe position requires the use of a separate tool, such as a screwdriver. This adjustment procedure is often not performed by the operator because the procedure consumes appreciable time and is cumbersome. Moreover, the separate tool necessary to loosen or tighten the screws is, more often than not, lost or misplaced. Consequently, optimum positioning of the shoe for a given application may often not be achieved.
Another form of guide shoe adjustment mechanism is shown in U.S. Pat. No. 5,007,172 to Palm. According to that patent, adjustment is accomplished by rotating a lever. Attached to this lever is a lock pin which is pivotally mounted in the front end of the gear housing transverse to the shoe support. The pin's geometry comprises a “D” shaped formation having the rounded portion thereof adapted for engagement in a selected one of three arcuate grooves formed in the support to secure the support, and hence the shoe, into the desired position. To release and reposition the shoe, the lever is rotated allowing the flat portion of the pin to be parallel with the flat portion of the support thereby providing clearance which permits the support and shoe to move freely. When the shoe has been moved to its desired position, the lever is rotated back enabling the rounded portion of the pin to engage and be received in the selected arcuate groove in the support thereby to establish the new position for the shoe.
U.S. Pat. No. 5,421,091 to Gerritsen, Jr. discloses another tool-less-type guide shoe. The mechanism described in that patent includes a bracket, to which the foot is pivotally connected, that includes a plurality of slots and a button that engages in the slots to secure the shoe in a selected position. The button extends through the housing in the saw and is spring biased into the slots. The user depresses the button and moves the bracket to a selected position. The button is released and is returned to a locked position within the slot.
The guide shoes of the prior art, including those that require tools and those that do not, can be removed from the housing of the saw. Typically, the shoe is removed by pulling the foot and the bracket or support comes straight out of the housing. This arrangement can make it awkward to insert the guide shoe into the housing if the guide shoe is inadvertently removed. In addition, the guide shoe can be removed when the blade is attached to the blade holder.
SUMMARY OF THE INVENTION
The present invention provides a tool-less guide shoe mechanism for a power tool which does not require a separate tool for adjustment purposes and which incorporates a self-positioning and self-locking feature. In addition, the mechanism provides a means to restrict the removal of the guide shoe from the housing of the saw. Further, the mechanism of the present invention can be readily and inexpensively manufactured and incorporated in the housing of a power reciprocating saw.
The tool-less guide shoe for the present invention can be used as a part of a reciprocating saw, or an oscillating saw. The saw includes a housing having a nose section. The saw blade is connected to a blade holder that projects from the nose section. The blade holder moves in a reciprocating pattern by way of a motor. The nose section includes a receiving hole that is in a parallel space relationship with the blade holder. The tool-less guide shoe of the present invention is received in the hole.
The tool-less guide shoe includes a post, a bracket welded to the lower end of the post and a foot that is pivotally mounted to the bracket by pins. Towards the upper end of the post, the post includes a plurality of laterally arranged locking slots. At the upper end, the post includes a stop plate and a removal slot that is rotationally adjacent the stop plate The post also includes a positioning slot which extends between the stop plate and the locking slots.
The post of the present invention is held in position, and allowed to move relative the nose section, by a locking plate. The locking plate is generally L-shaped having a locking portion as the foot and a positioning portion as the leg. The locking plate moves through a slot in the nose section between an engaged position and an open position. In the engaged position, the locking portion is positioned within the locking slots to secure the guide shoe in a selected position relative the nose section. In the open position, the locking portion is pushed out of the locking slots and the positioning portion is placed adjacent the post such that the post can move through the positioning slot between the plurality of locking slots and the stop plate. In the open position, the guide shoe is removed by putting the locking plate in the open position and pulling the guide shoe away from the nose so that the locking plate is adjacent the stop plate. In this position, the guide shoe is rotated approximately
90
° so that the locking plate is positioned in the removal slot. In order to rotate the guide shoe, the blade must be removed from the blade holder. Otherwise, the blade extends through the foot portion of the guide shoe and prevents the guide shoe from rotating.
These and numerous other features and advantages of the present invention will become readily apparent from the following description, the accompanying drawings and the appended claims.
REFERENCES:
patent: 3360021 (1967-12-01), Mejia
patent: 4113221 (1978-09-01), Wehner
patent: 4619170 (1986-10-01), Maier et al.
patent: 4913204 (1990-04-01), Moores et al.
patent: 5007172 (1991-04-01), Palm
patent: 5016354 (1991-05-01), Baine
patent: 5090461 (1992-02-01), Gakhar et al.
patent: 5421091 (1995-06-01), Gerritsen, Jr.
patent: 5593244 (1997-01-01), Ruckert
patent: 35 20 309 A1 (1986-12-01), None
patent: 43 27 381 A1 (1995-02-01), None
patent: 24 35 845 A1 (1975-02-01), None
Gardner Carton & Douglas
S-B Power Tool Company
Watts Douglas D.
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