Portable power saw with safety switch means to preclude operation except when the saw is in engagement with the workpiece

• US 3,331,408 A
• Filed: 09/08/1965
• Issued: 07/18/1967
• Est. Priority Date: 09/08/1965
• Status: Expired due to Term

• Current Assignee: Harry G. Condit
• Original Assignee: Harry G. Condit
• Inventors: Condit, Harry G.
• Application Number:
  US04/485,729
• Time in Patent Office: 678 Days
• US Class Current: 30/374
• CPC Class Codes: B23D 59/001 Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade measuring in general G01; controlling in general G05
• CPC Class Codes: B27B 9/00 Portable power-driven circular saws for manual operation details or components, e.g. handles, casings, of portable power-driven tools not particularly related to the operation performed B25F5/00
• CPC Class Codes: Y10T 83/544 With trip-switch in work-sensing mechanism

Claims

4. IN A POWER HAND SAW INCLUDING A FRAME HAVING A SOLE PLATE WITH A WORK-ENGAGING SURFACE ADAPTED FOR SUPPORTING CONTACT WITH A WORKPIECE, A CIRCULAR SAW BLADE ROTATABLY MOUNTED ON SAID FRAME AND PROJECTING BEYOND SAID WORK-ENGAGING SURFACE FOR CUTTING ENGAGEMENT WITH THE WORKPIECE, A MOTOR MOUNTED ON SAID FRAME AND CONNECTED TO SAID BLADE FOR DRIVING THE LATTER IN ROTATION, AND A MANUAL SWITCH ON SAID FRAME FOR CONTROLLING SAID MOTOR, SAID SWITCH HAVING AN ACTUATING MEMBER MOVABLE BETWEEN A NORMAL OFF POSITION AND AN ON POSITION, THE IMPROVEMENTS COMPRISING:

A SECOND ELONGATGE SWITCH ACTUATING MEMBER DISPOSED WITHIN AN OPENING IN SAID SOLE PLATE AND EXTENDING PARALLEL TO THE PLANE OF SAID BLADE, SAID SECOND MEMBER HAVING ONE END LOCATED IN ADVANCE OF SAID BLADE AND ITS OTHER END LOCATED REARWARDLY OF THE ROTATION AXIS OF SAID BLADE, MEANS MOUNTING SAID ONE END OF SAID SECOND MEMBER ON SAID SOLE PLATE FOR PIVOTAL MOVEMENT OF SAID SECOND MEMBER BETWEEN A NORMAL OFF POSITION WHEREIN SAID MEMBER PROJECTS BEYOND SAID WORK-ENGAGING SURFACE AND AN ON POSITION WHEREIN SAID MEMBER IS SUBSTANTIALLY FLUSH WITH SAID SURFACE, A SAFETY SWITCH MOUNTED ON SAID FRAME AND MEANS OPERATIVELY CONNECTING SAID WORK SWITCH TO SAID SECOND SWITCH ACTUATING MEMBER FOR ACTUATION OF SAID WORK SWITCH IN RESPONSE TO MOVEMENT OF SAID SECOND ACTUATING MEMBER BETWEEN SAID OFF AND ON POSITIONS THEREOF, CIRCUIT MEANS ELECTRICALLY CONNECTING SAID SWITCHES TO SAID MOTOR IN SUCH MANNER THAT SAID MOTOR IS CONDITIONED TO BE ENERGIZED IN RESPONSE TO SIMULTANEOUS MOVEMENT OF SAID SWITCH ACTUATING MEMBERS TO SAID ON POSITIONS THEREOF AND SAID MOTOR IS DE-ENERGIZED IN RESPONSE TO MOVEMENT OF EITHER SWITCH ACTUATING MEMBER TO SAID OFF POSITION, AND LATCH MEANS FOR SELECTIVELY LATCHING SAID SECOND SWITCH ACTUATING MEMBER IN SAID ON POSITION THEREOF.