Cutlery – Cutting tools – Saw
Reexamination Certificate
1999-07-13
2001-10-30
Payer, Hwei-Siu (Department: 3724)
Cutlery
Cutting tools
Saw
C030S374000, C030S392000
Reexamination Certificate
active
06308423
ABSTRACT:
This application claims priority on Japanese Patent Application No. 10-200801, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to cutting tools, such as reciprocating saws. More particularly, the present invention relates to a reciprocating saw having a guide member coupled to a main housing for use in cutting workpieces.
2. Description of the Related Art
Cutting tools, such as reciprocating saws, commonly includes in front of a main housing a guide shoe or other guide member which is pressed against a workpiece during operation. The guide member is coupled to a slide shaft which is slidably provided in the main housing and is oriented parallel to the blade of the reciprocating saw. The blade commonly protrudes from the front end of the main housing. The slide shaft is secured to the main housing by a screw, such as a hexagon head bolt. To fix the guide member in a desired slide position with respect to the main housing, the hexagon head bolt is first loosened and the slide shaft is pulled out or retracted to the desired position. The hexagon head bolt is then tightened again to secure the slide shaft to the main housing, thus fixing the guide member in the desired position.
Conventional reciprocating saws require a tool, such as a hexagonal wrench in order to tighten and loosen the bolt. To overcome this inconvenience, the applicant proposed in Japan Published Unexamined Utility Model Application No. 6-31916 a structure for permitting the position of the guide member to be adjusted without the use of any tool. In this structure, a manually-operated lever attached to the hexagon head bolt is rotated to tighten and loosen the bolt so as to adjust the position of the slide shaft and thus the guide member with respect to the main housing.
In the foregoing structure, however, if the lever protrudes at an angle from the main housing, the operator may have difficulty maintaining a secure hold on the main housing. Therefore, care must be taken during assembly of the tool at the plant to fit the manually-operated lever in an accommodating recess formed in the housing when the hexagon head bolt, is properly tightened to secure the slide shaft to the housing. As can be imagined, it is a troublesome and difficult task to coordinate the tightening rotation of the hexagon head bolt with the angle of the lever so that the lever is conveniently accommodated in the recess when the bolt is properly torqued.
SUMMARY OF THE INVENTION
In view of the above-identified problems, an important object of the present invention is to provide a cutting tool which permits a manually-operated lever to be easily and accurately assembled to the slide shaft so that the lever is rotated to an unobstructive position when the screw or bolt for fixing the slide shaft is properly tightened.
Another object of the present invention is to provide a cutting tool the guide shoe of which can be easily repositioned without obstructing or interfering with the operator's handling of the tool.
The above objects and other related objects are realized by the invention, which provides a cutting tool including: a housing; a guide member slidably attached to the housing; a screw member having an axis for securing the guide member in a desired position; a screw-tightening lever for rotating the screw member to secure the guide member; and a receiving portion for accommodating the screw-tightening lever at a rotational position of the screw member where the screw member secures the guide member. In this cutting tool, the screw-tightening lever includes an internal lever which is connected to the screw member and an outer lever attached to the screw member so as to pivot with the screw member on the axis of the screw member. The screw-tightening lever further includes a coupling means for connecting the internal lever to the outer lever in the receiving portion within a predetermined range of deviation from a predetermined position so that the outer lever remains within a predetermined range of positions within the receiving portion at said rotational position of the screw member.
According to one aspect of the present invention, the screw member is a bolt having a head and the internal lever is connected to the bolt by fitting the head of the bolt into a polygonal socket hole formed in the internal lever so that the internal lever is pivotal on the bolt head and the pivotal position of the internal lever with respect to the bolt head is changeable by a plurality of predetermined units of angle corresponding to the angle of the corners of the polygonal socket hole. Additionally, the coupling means of the screw-tightening lever comprises a plurality of compensation teeth formed on the outer lever and a plurality of engaging teeth formed on the internal lever so as to engage the compensation teeth within a range of pivotal positions no less than the predetermined unit of pivotal angle of the internal lever with respect to the bolt head.
According to another aspect of the present invention, the internal lever is shaped substantially symmetrically about a longitudinal center line which extends substantially parallel to the guide member, the outer lever is shaped substantially symmetrically about a longitudinal center line which extends substantially parallel to the guide member, and the two center lines pass through the axis of the screw member. In the cutting tool according to the invention, the deviation of the internal lever from the predetermined position may be that caused by pivoting of the longitudinal center line of the internal lever from that of the outer lever.
According to still another aspect of the present invention, the bolt is a hexagonal head bolt and the angle of each corner of the polygonal hole in the internal lever is approximately 120 degrees, so that the predetermined unit of pivotal angle is approximately 30 degrees. Moreover, the compensation teeth and the engaging teeth may be located along a common circumference with the axis of the hexagonal head bolt as the center and the internal lever is formed with four engaging teeth at intervals of four degrees around the axis of the hexagonal head bolt, thus spanning a sixteen degree range, with the center line of the inner lever symmetrically dividing the four engaging teeth into two on each side of the line, and the compensation teeth are formed at intervals of four degrees around the axis of the hexagonal head bolt, with the center line of the outer lever symmetrically dividing the compensation teeth into approximately equal numbers of teeth on either side of the line, so as to allow the internal lever to have plurality of pivotal positions of at least a 30 degree range.
According to yet another aspect of the present invention, the screw-tightening lever further includes a means for maintaining engagement between the internal lever and the outer lever.
In accordance with another aspect of the present invention, the means for maintaining engagement includes a connection plate which has a circular hole at a first end thereof for being fitted around the hexagonal head bolt and a slot at a second end thereof. The means for maintaining engagement further includes a screw means for being tightened into the outer lever through the slot of the connection plate, with the internal lever interposed between the outer lever and the connection plate.
In one practice, the receiving portion is a recess provided in the housing of the tool and configured so that the screw-tightening lever is located in an unobstructive position for manual handling when accommodating the screw-tightening lever.
In another practice, the outer lever further includes a recess for accommodating the head of the hexagonal head bolt, the inner lever, and the means for maintaining engagement.
To carry out the invention in one preferred mode, the guide member is a guide shoe which includes a shaft portion having a first end slidably inserted in the housing and a second end protruding from a front end of the ho
Foley Hoag & Eliot LLP
Makita Corporation
Payer Hwei-Siu
LandOfFree
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