Miter saw

• US 5,392,678 A
• Filed: 08/25/1993
• Issued: 02/28/1995
• Est. Priority Date: 08/27/1992
• Status: Expired due to Term

• Current Assignee: Makita Corporation
• Original Assignee: Makita Corporation
• Inventors: Shibata, Yoshinori, Sasaki, Katsuhiko, Niinomi, Mitsuyoshi
• Primary Examiner(s): Jones, Eugenia
• Assistant Examiner(s): SCHROCK, ALLAN
• Application Number:
  US08/111,479
• Time in Patent Office: 552 Days
• Field of Search: 83/471.3, 83/486.1, 83/581, 83/473, 83/698, 83/699, 83/468.3, 83/477.1, 83/676, 83/564, 403/111, 403/112, 403/113, 403/117
• US Class Current: 83/471.3
• CPC Class Codes: B23D 45/044 the saw blade being adjustable according to angle of cut B23D45/025 takes precedence
• CPC Class Codes: B23D 45/046 the pivoted lever being mounted on a carriage
• CPC Class Codes: B23Q 11/0025 using resilient means, e.g. springs, hydraulic dampers
• CPC Class Codes: B27G 5/02 for sawing mitre joints; Mitre boxes guide fences for timber in sawing machines B27B27/00
• CPC Class Codes: Y10T 83/7697 Tool angularly adjustable relative to work-support
• CPC Class Codes: Y10T 83/7705 Adjustable angular relationship
• CPC Class Codes: Y10T 83/7726 By movement of the tool
• CPC Class Codes: Y10T 83/8749 By pivotal motion
• CPC Class Codes: Y10T 83/8773 Bevel or miter cut
• CPC Class Codes: Y10T 83/9403 Disc type
• CPC Class Codes: Y10T 83/9461 Resiliently biased connection

Abstract

A miter saw includes a base on which a work is placed. A miter saw unit supports a saw blade and has a motor for rotatably driving the saw blade. A support mechanism is provided supporting the miter saw unit relative to the base in such a manner that the miter saw unit is laterally leftwardly and rightwardly pivotable from a vertical position. A biasing member is interposed between the miter saw unit and the base for biasing the miter saw unit in a direction opposite to at least one of the directions of the lateral pivotal movement of the miter saw unit when the miter saw unit is laterally pivoted.

Claims

1. A miter saw comprising:

a base on which a work is placed;

a miter saw unit supporting a saw blade and having a motor for rotatably driving said saw blade;

a support mechanism supporting said miter saw unit relative to said base in such a manner that said miter saw unit is laterally leftwardly and rightwardly pivotable in opposed directions from a vertical position and respectively toward left and right predetermined positions; and

biasing means interposed between said miter saw unit and said base and defining a biasing force for biasing said miter saw unit in a direction opposite to at least one of said opposed directions of the lateral pivotal movement of said miter saw unit when said miter saw unit is laterally pivoted in said at least one of said opposed directions;

said biasing force of said biasing means being weaker than the gravitational force acting on the miter saw unit permitting a lateral pivotal movement of said miter saw unit, including said motor, toward a corresponding one of said left and right predetermined positions against said biasing force upon pivotal movement of said miter saw unit in said at least one of said opposed directions from said vertical position.

2. The miter saw as defined in claim 1 wherein said support mechanism includes a movable support member on which said miter saw unit is mounted and a fixed support member mounted on said base;

said movable support member is pivotally supported by said fixed support member around a pivotal axis extending in substantially horizontal direction.

3. The miter saw as defined in claim 2 wherein said biasing means applies no biasing force to said miter saw unit when said miter saw unit is positioned at a neutral position where the center of gravity of said miter saw unit and said movable support member is positioned substantially on said pivotal axis.

4. The miter saw as defined in claim 3 wherein said biasing means provides a greater biasing force as said miter saw unit is pivoted from said neutral position.

5. The miter saw as defined in claim 3 wherein said neutral position is displaced from said vertical position;

said biasing means applies the biasing force against the moment produced by the gravitational force acting on said miter saw unit and said movable support member when said miter saw unit is positioned at said vertical position.

6. The miter saw as defined in claim 5 wherein said motor is disposed on one lateral side of said miter saw unit, so that said neutral position is displaced from said vertical position toward a direction opposite to said one lateral side.

7. The miter saw as defined in claim 5 and further including stopper means operable to determine the position of pivotal movement of said miter saw unit at any one of said vertical position, said left predetermined position and said right predetermined position;

said stopper means engages said miter saw unit at both said left predetermined position and said right predetermined position against the moment produced by the gravitational force acting on said miter saw unit and said movable support member; and

the biasing force of said biasing means being smaller than the moment force produced by the gravitational force acting on said miter saw unit and said movable support member.

8. The miter saw as defined in claim 2 wherein said biasing means is a torsion coil spring having one end engaged by said movable support member and having the other end engaged by said fixed support member, so that said torsion coil spring applies the biasing force to said miter saw unit when said miter saw unit is laterally pivoted in either of said opposed directions;

and said torsion coil spring has an axis which substantially coincides with said pivotal axis.

9. The miter saw as defined in claim 8 wherein said fixed support member includes a cylindrical support portion;

said movable support member includes a cylindrical rotational portion;

said support portion and said rotational portion have central axes which coincides with said pivotal axis;

said rotational portion is rotatably connected to said support portion around said pivotal axis; and

said support portion and said rotational portion cooperatively form a space therewithin for accommodating said torsion coil spring.

10. The miter saw as defined in claim 9 wherein said fixed support member further includes a support shaft extending into said space;

said support shaft cooperates with said support portion for rotatably supporting said rotational portion;

said torsion coil spring is slidably fitted on said support shaft;

said one end of said torsion spring is engaged by a first engaging portion disposed on said support portion;

said other end is engaged by a second engaging portion disposed on said rotational portion.

11. The miter saw as defined in claim 2 wherein said biasing means is a tension coil spring having one end engaged by said movable support member and having the other end engaged by said fixed support member.

12. The miter saw as defined in claim 11 wherein said fixed support member includes a cylindrical support portion;

said movable support member includes a cylindrical rotational portion;

said support portion and said rotational portion have central axes which coincides with said pivotal axis;

said rotational portion is rotatably connected to said support portion around said pivotal axis; and

said support portion and said rotational portion cooperatively form a space therewithin for accommodating said tension coil spring.

13. The miter saw as defined in claim 12 wherein said fixed support member further includes a support shaft extending into said space;

said support shaft cooperates with said support portion for rotatably supporting said rotational portion;

a lever is pivotally mounted on said support shaft; and

said one end of said tension coil spring is engaged by said support portion through said lever; and

said other end of said tension spring is connected to a part of said rotational portion.