SAFETY GUARD FOR A BREAKING SAW

• US 3,805,639 A
• Filed: 11/21/1972
• Issued: 04/23/1974
• Est. Priority Date: 11/21/1972
• Status: Expired due to Term

• Current Assignee: Joseph E. Peter
• Original Assignee: Joseph E. Peter
• Inventors: Peter, Joseph E.
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): Shoemaker, F. D.
• Application Number:
  US05/308,532
• Time in Patent Office: 518 Days
• Field of Search: 74/616 30/391,390 83/860
• US Class Current: 74/616
• CPC Class Codes: B23Q 11/06 Safety devices for circular cutters
• CPC Class Codes: F16P 3/10 in which the operation of locking the door or other member causes the machine to start
• CPC Class Codes: Y10T 74/2198 Operator controlled
• CPC Class Codes: Y10T 83/96 Guard

Abstract

A safety guard for a breaking saw that automatically closes to protect the entire periphery of the saw'"'"''"'"'s circular blade as soon as the saw'"'"''"'"'s power is cut off, and that automatically opens to expose the saw'"'"''"'"'s circular blade for cutting as soon as the saw'"'"''"'"'s power is turned on. The safety guard structure includes a fixed cover mounted to the saw for protecting one segment of the circular blade, and a movable cover characterized by a pair of clamshells for protecting the other segment. The clamshells are adapted to pivot about the circular blade'"'"''"'"'s rotational axis between a closed position and an open position, the clamshells overlying the circular blade'"'"''"'"'s periphery for protecting against inadvertent contact when in the closed position and exposing the circular blade'"'"''"'"'s periphery for cutting when in the open position. An open/close motor is mounted to the fixed cover for automatically opening and closing the clamshells, the open/close motor also being interconnected with the saw'"'"''"'"'s drive motor (thereby interconnecting the open/close motor with the drive motor'"'"''"'"'s off/on switch). The open/close motor is energized when the drive motor'"'"''"'"'s off/on switch is activated by an operator to commence rotation of the circular blade, thereby automatically retracting the clamshells from the closed to the opened position. The open/close motor is spring loaded to drive the clamshells from the opened to the closed position when the drive motor'"'"''"'"'s off/on switch is released by the operator, thereby automatically returning the clamshells from the opened to the closed position.

Claims

1. A safety guard for a power saw, said power saw including a circular blade, comprising a fixed cover mounted to said saw to protect one segment of said circular blade, said fixed cover being maintained in fixed relation to said saw by attaching means, a movable cover pivotally mounted to said saw to protect the other segment of said circular blade, said movable cover being adapted to pivot between a closed position where same overlies the blade'"'"''"'"'s periphery for protecting against inadvertent contact with that periphery, and an opened position where same exposes the circular blade'"'"''"'"'s periphery for cutting, and said movable cover being pivotally mounted to said fixed cover, and an open/close motor interconnected with said movable cover and interconnected with said circular blade'"'"''"'"'s off/on switch, said open/close motor automatically opening said movable cover to the opened position when said off/on switch is activated by an operator and automatically closing said movable cover to the closed position when said off/on switch is deactivated by an operator, said open/close motor being mounted on said fixed cover, thereby allowing the circular blade to be changed simply by releasing said attaching means and removing the safety guard relative to the saw'"'"''"'"'s housing to expose said circular blade.

2. A safety guard for a saw as set forth in claim 1 wherein said movable cover is adapted to pivot between opened and closed positions about the rotational axis of said circular blade, said movable cover including two clamshells which retract away from one another to expose said circular blade as said movable cover pivots open and which extend toward one another to guard said circular blade as said movable cover pivots closed.

3. A safety guard for a saw as set forth in claim 2, said open/close motor including a yoke characterized by pivotal arms with each arm of said yoke being interconnected with one of said clamshells, said yoke being movable relative to the circular blade by said open/close motor to effect oscillation of said clamshells in opposite directions one from the other between opened and closed attitudes, and said open/close motor being one of a pneumatic motor, a hydraulic motor, and an electrical solenoid with said yoke being directly interconnected with said motor.

4. A safety guard for a power saw, said power saw including a circular blade, comprising a fixed cover mounted to the saw to protect one segment 0f said circular blade, a movable cover pivotally mounted to said fixed cover to protect the other segment of said circular blade, said movable cover including two separate clamshells adapted to pivot about the circular blade'"'"''"'"'s rotational axis in opposite directions one from the other when being opened and closed between a closed position where same overlie the circular blade'"'"''"'"'s periphery for protecting against inadvertent contact with that periphery and an opened position where same exposes the circular blade'"'"''"'"'s periphery for cutting, and first stop means associated with said two clamshells for stopping pivotal movement of said clamshells in the closed position.

5. A safety guard for a saw as set forth in claim 4 including second stop means associated with said two clamshells for stopping pivotal movement of said clamshells in the opened position.

6. A safety guard for a saw as set forth in claim 4 including an open/close motor interconnected with said clamshells, said open/close motor being directly interconnected with the off/on switch for the circular blade'"'"''"'"'s drive motor, said clamshells being pivoted to the opened position when the off/on switch is activated by an operator and said clamshells being pivoted to the closed position when the off/on switch is deactivated by an operator.

7. A safety guard for a saw as set forth in claim 6 including a yoke characterized by pivotal arms with each arm of said yoke being interconnected respectively with one of said clamshells and the crossbar of said yoke being interconnected with said open/close motor, said arms being located on opposite sides of the circular blade'"'"''"'"'s rotational axis and on opposite sides of the imaginary line along which said yoke is reciprocated by said open/close motor.

8. A safety guard for a power saw as set forth in claim 4 wherein said fixed cover is adapted to enclose and protect between about 90* and about 180* of said circular blade'"'"''"'"'s periphery, and wherein said clamshells are adapted to enclose and protect the remainder of said circular blade'"'"''"'"'s periphery, said clamshells being located in different planes and being adapted to overlap one another beneath said fixed cover when said movable cover is opened.