Safety mechanism for saws

• US 4,756,220 A
• Filed: 01/09/1987
• Issued: 07/12/1988
• Est. Priority Date: 12/18/1985
• Status: Expired due to Fees

• Current Assignee: Engineering Consulting Services Eight South Montgomery Street San Jose California
• Original Assignee: Engineering Consulting Services Limited
• Inventors: Olsen, Joseph C., Steinbach, Richard H.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/001,703
• Time in Patent Office: 550 Days
• Field of Search: 83/DIG. 1, 83/490, 83/453, 83/399, 83/374, 83/375, 83/581, 30/388
• US Class Current: 83/375
• CPC Class Codes: B23D 47/04 of devices for feeding, positioning, clamping, or rotating work
• CPC Class Codes: B23Q 11/00 Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work accessories specially designed for sawing machines or sawing devices B23D59/00; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools in respect of boring or drilling machines B23B47/32 takes precedence; safety devices in general F16P
• CPC Class Codes: F16P 3/20 for electric control systems
• CPC Class Codes: Y10S 83/01 Safety devices
• CPC Class Codes: Y10T 83/5669 Work clamp
• CPC Class Codes: Y10T 83/5724 With provision for manual control of clamp
• CPC Class Codes: Y10T 83/7493 Combined with, peculiarly related to, other element
• CPC Class Codes: Y10T 83/7788 Tool carrier oscillated or rotated

Abstract

An improvement is set forth in a sawing apparatus having a table supporting a workpiece, a fence for guiding the workpiece and an operator moveable electrically operated saw having a first normally biased off switch controlling application of electric power to the apparatus, the switch being positioned to be controlled by the hand of an operator which controls movement of the saw. The improvement comprises a second normally biased off switch connected in series with the first normally biased off switch, the second switch being mounted adjacent to the fence a sufficient distance from the saw blade to prevent the saw blade from contacting the operator'"'"'s off hand when the off hand is activating the second switch and in a position whereat the off hand can, simultaneously with activating the second switch, adjust the position of the workpiece along the fence. Since in order for the saw blade to rotate both hands of an operator must be holding onto normally off switches and since both switches are in positions removed from the area of movement of the saw blade, the operator is protected from accidently cutting himself. Yet, the apparatus allows the operator adequate control of the workpiece being cut and further allows a radial arm saw to function as a ripping saw without interference.

Claims

1. In a sawing apparatus having a table for supporting a workpiece, a fence for guiding the workpiece and an operator moveable electrically powered saw blade having a first normally biased off switch controlling application of electric power to said sawing apparatus, said switch being positioned to be controlled by a hand of an operator which controls movement of the saw blade, an improvement comprising:

a pair of normally biased off switches connected in parallel to one another and in series with said first normally biased off switch, said switches of said pair being mounted adjacent to said fence, one to the left of said saw blade and the other to the right of said saw blade, the switches of said pair being located a sufficient distance from the saw blade to prevent the saw blade from contacting the off hand of the operator when the off hand is activating either of said switches of said pair, the switches of said pair being positioned to be controlled by the off hand of the operator while the off hand is adjacent said fence in position to adjust the position of said workpiece.

2. An improved sawing apparatus as set forth in claim 1, further including:

an additional normally biased off switch connected in parallel across said first switch and said pair of switches, said additional switch being selectively positionable in its on position.

3. An improved sawing apparatus as set forth in claim 1, further including:

means for braking the saw blade in response to interruption of said electric power.

4. In a sawing apparatus having a table supporting a workpiece, a fence for guiding the workpiece and an operator moveable electrically powered saw blade having a first normally biased off switch controlling application of electric power to said sawing apparatus, said switch being positioned to be controlled by a hand of an operator which controls movement of the saw blade, an improvement comprising:

a second normally biased off switch connected in series with said first normally biased off switch, said second switch being mounted adjacent to said fence a sufficient distance from said saw blade to prevent the saw blade from contacting the off hand of the operator when the off hand is activating the second switch and in a position whereat the off hand of the operator can, simultaneously with activating the second switch, adjust the position of the workpiece along the fence.

5. An improved sawing apparatus as set forth in claim 4, further including:

an additional normally biased off switch connected in parallel across said first switch and said pair of switches, said additional switch being selectively positionable in its on position.

6. An improved sawing apparatus as set forth in claim 4, further including:

means for braking the saw blade in response to interruption of said electric power.