CIRCULAR SAW WITH IMPROVED MOVABLE GUARD CONSTRUCTION

• US 3,730,239 A
• Filed: 12/10/1971
• Issued: 05/01/1973
• Est. Priority Date: 12/10/1971
• Status: Expired due to Term

• Current Assignee: Frank A. Kaman, Harold Mcconnaughay
• Original Assignee: Frank A. Kaman, Harold Mcconnaughay
• Inventors: Kaman, Frank A., McConnaughay, Harold
• Primary Examiner(s): Schran, Donald R.
• Application Number:
  US05/206,639
• Time in Patent Office: 508 Days
• Field of Search: 143/159H,159R 30/391
• US Class Current: 30/391
• CPC Class Codes: B27B 9/02 Arrangements for adjusting the cutting depth or the amount of tilting
• CPC Class Codes: B27G 19/04 for manually-operated power-driven circular saws

Abstract

The adjustably mounted base plate carries a first abutment formation adjacent the trailing end of the slot which is formed therein to receive the circular saw blade. The lower blade guard has a second abutment formation thereon adjacent its workengaging forward end. The second abutment formation is brought into abutting engagement with the first abutment formation upon movement of the lower blade guard toward its open position whereby the lower blade guard exposes only the blade teeth which extend through the slot in the base plate irrespective of the angular disposition of the latter. A manually operated retracting mechanism for the lower blade guard includes linkage operated by a handle mounted on the side of the fixed blade guard which is adjacent the tool motor.

Claims

1. In a portable, power operated circular saw of the type having a powered blade mounting shaft and a frame including a fixed blade guard adapted to enclose the teeth on the upper portion of a circular blade mounted on said shaft, a base plate having an elongated slot for receiving a portion of the circular blade therethrough, pivot means securing said base plate to said frame adjaCent the leading end of the former for pivoting movement about an axis parallel with the axis of rotation of said shaft back and forth between a normal position and an inclined position, and adjustment means for securing said base plate in said positions and in any location therebetween, the improvement comprising:

a. a first abutment formation on said base plate adjacent the trailing end of said slot;

b. a lower blade guard mounted on said frame for swinging movement back and forth between a closed position and an open position, which lower blade guard in the closed position thereof cooperates with said upper blade guard to enclose substantially all of the teeth on the blade; and

c. said lower blade guard having a work engaging forward end and a second abutment formation thereon which is adjacent said forward end, said second abutment formation being brought into abutting engagement with said first abutment formation upon movement of said lower blade guard from the closed position thereof toward the open position thereof whereby the lower blade guard exposes only the blade teeth which extend through said slot and beneath said base plate irrespective of the location of the base plate between said positions thereof.

2. The improvement according to claim 1 further defined by:

a. said adjustment means including an adjustment arm mounted on said base plate adjacent the trailing end of said slot, said first abutment formation being integral with said arm; and

b. said second abutment formation being integral with said lower blade guard.

3. The improvement according to claim 1 further defined by a manually operated retracting mechanism for said lower blade guard, said mechanism comprising:

a. an operating lever pivotally mounted on the side of said fixed blade guard which is adjacent the power means for rotating said shaft;

b. connecting means engaged with said lever and said lower blade guard for moving the latter between said positions thereof in response to movement of said lever; and

c. biasing means engaged with said frame and said lower blade guard for urging the latter toward said closed position thereof.

4. The improvement according to claim 3 wherein said connecting means includes a pair of links, one link being secured at one end thereof to said lever for movement in unison with the latter, the other link having one of its ends pivotally connected with the other end of said one link and having its other end pivotally connected with said lower blade guard.

5. The improvement according to claim 4 wherein said other link is bent intermediate the ends thereof and has its respective ends disposed generally above and below said shaft when said lower blade guard is in said closed position thereof thereby to increase the mechanical advantage of said links for facilitating manual operation of said retracting mechanism.