Safety for fastener driving tool

Abstract

A pneumatic fastener driving tool includes a safety arrangement that requires the tool to be placed against a workpiece before a manual trigger valve is operated in order to permit the tool to fire. Once the tool is placed against the workpiece the safety arrangement prevents "touch" firing by moving the tool toward and away from the workpiece. In two embodiments, the safety arrangement includes a piston valve which is fluid operated to close off a control line to the main valve of the tool whenever the trigger is operated before the tool is placed against a workpiece and when an attempt is made to "touch" fire the tool with the trigger held operated. In a third embodiment, metering orifices in a valve actuated by moving the tool against a workpiece prevent repeated "touch" operation of the tool.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. In a tool for driving fasteners into a workpiece using a pressurized fluid motor for actuating a fastener driving means, a manually actuated trigger valve means,   a safety means actuated by placing the tool adjacent the workpiece,   fluid actuated valve means controlled by the trigger valve means and the safety means for controlling the application of pressurized fluid to the fluid motor,   and a control means including a fluid pressure operated piston means, said control means interconnecting the trigger valve means and the safety means to prevent the operation of the fluid actuated valve means unless the safety means is first actuated followed by the actuation of the trigger valve means.   
     
     
       2. In a tool for driving fasteners into a workpiece using a fluid motor actuated driving means, a fluid actuated valve means for controlling the application of pressurized fluid to the fluid motor,   a trigger valve means,   a safety valve means actuated by placing the tool adjacent the workpiece,   passage means coupling the trigger and safety valve means to the fluid actuated valve means to control the operation of the fluid actuated valve means,   and control means coupled to said passage means and controlled by the trigger and safety valve means for preventing actuation of the fluid actuated valve means unless the safety valve means is first operated followed by the trigger valve means.   
     
     
       3. In a tool for driving fasteners into a workpiece using a fluid motor actuated driving means, a fluid actuated valve means for controlling the application of pressurized fluid to the fluid motor;   a trigger valve means,   a safety valve means actuated by placing the tool adjacent the workpiece,   passage means coupling the trigger and safety valve means to the fluid actuated valve means to control the operation of the fluid actuated valve means,   and a fluid actuated valve in said passage means having both a normal position and an operated position, said fluid actuated valve being selectively coupled to pressurized fluid and the atmosphere by one of said trigger and safety valve means and being actuated from said normal position to said operated position to prevent operation of said fluid actuated valve means in response to the actuation of one of said trigger and safety valve means prior to the operation of the other of said valve means.   
     
     
       4. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, a trigger valve means,   a safety means actuated by placing the tool adjacent the workpiece,   means controlled by the trigger valve means and the safety means for controlling the application of pressurized fluid to the fluid motor,   a movably mounted means movable between a first position permitting the application of fluid to the fluid motor and a second position preventing the application of fluid to the fluid motor, said movably mounted means having a fluid pressure responsive surface,   and passage means communicating with the fluid pressure responsive surface and coupling said surface to the trigger valve means for controlling the fluid pressure applied to said surface so that the movement of the movably mounted means to its first and second positions is controlled in dependence on the sequence in which the trigger valve means and the safety means are operated.   
     
     
       5. The tool set forth in claim 4 in which the tool includes a reservoir of pressurized fluid,   and the trigger valve means is operable to alternate positions connecting said surface to the reservoir and the atmosphere.   
     
     
       6. The tool set forth in claim 5 including biasing means biasing the movably mounted means to its second position,   and in which the trigger valve means normally connects said surface to the reservoir to hold the movably mounted means in its first position against the bias of the biasing means.   
     
     
       7. The tool set forth in claim 6 in which the biasing means includes pressurized fluid supplied in dependence on the position of the safety means, which pressurized fluid is removed by the actuation of the safety means.   
     
     
       8. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, a trigger valve means,   a safety means actuated by placing the tool adjacent the workpiece,   means controlled by the trigger valve means and the safety means for controlling the application of pressurized fluid to the fluid motor,   a movably mounted means movable between a first position permitting the application of fluid to the fluid motor and a second position preventing the application of fluid to the fluid motor, said movably mounted means having a fluid pressure responsive surface for controlling the movement of the movably mounted means,   and means including passage means supplying a biasing pressurized fluid to the fluid responsive surface on the movably mounted means and responsive to the position of the movably mounted means for permitting the trigger valve means and the safety means to effect the application of fluid to the fluid motor only when the safety means is operated first followed by the operation of the trigger valve means.   
     
     
       9. In a tool for driving fasteners into a workpiece using a fluid motor for actuating a fastener driver, fluid controlled main valve means for controlling the application of fluid to the fluid motor,   a trigger valve means,   passage means coupled to the main valve means and selectively connected to fluid pressure and the atmosphere by the trigger valve means to control the operation of the main valve means,   a slidable valve in said passage means movable to a first position closing the passage means and to a second position opening the passage means, said slidable valve having two opposed fluid responsive surfaces, one of said surfaces being selectively coupled to fluid pressure and the atmosphere under the control of the trigger valve means,   a safety means actuated by positioning the tool adjacent a workpiece,   and valve means controlled by the safety means for selectively coupling the other surface on the slidable valve to fluid pressure and the atmosphere.   
     
     
       10. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, trigger valve means operable between a normal and an operated position to control the application of fluid pressure to the fluid motor,   safety means biased to a normal position and actuated to an operated position against the bias when the tool is placed adjacent the workpiece, the trigger valve means and the safety means each being independently operable between their normal and operated positions to permit the trigger valve means and the safety means to be actuated to their operated position in any sequence,   first control means operated when both the trigger valve means and the safety means are in their operated positions for rendering the fluid pressure effective to operate the fluid motor,   and second control means for rendering the first control means ineffective unless the safety means is operated prior to the trigger valve means.   
     
     
       11. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, trigger valve means operable between normal and operated positions to control the application of fluid pressure to the fluid motor,   safety means biased to a normal position and actuated to an operated position against the bias when the tool is placed adjacent the workpiece, the trigger valve means and the safety means each being independently operable between their normal and operated positions to permit the trigger valve means and the safety means to be actuated to their operated position in any sequence,   first control means operated when both the trigger valve means and the safety means are in their operated positions for rendering the fluid pressure effective to operate the fluid motor,   and second control means operative following the actuation of the trigger valve means and the safety means to their operated positions for rendering the first control means ineffective to cause repeated operation of the fluid motor when the safety means is returned to its normal position and again actuated to its operated position.   
     
     
       12. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, fluid controlled main valve means for controlling the application of fluid pressure to the fluid motor,   trigger valve means,   safety means operable when the tool is disposed adjacent the workpiece, said safety means including a safety valve means,   passage means connected to and controlled by the trigger valve means and the safety valve means for selectively coupling fluid pressure and the atmosphere to the main valve means to control the operation of said main valve, the main valve means causing operation of the fluid motor only when both of the trigger valve means and the safety means are operated,   and control means coupled to the passage means and effective only after the fluid motor has been operated by the operation of the trigger valve means and the safety means for rendering the passage means ineffective to control additional operations of the fluid motor under the control of subsequent releases and reoperations of the safety means so long as the trigger valve means is maintained operated.   
     
     
       13. The tool set forth in claim 12 in which the safety valve means has a first position supply fluid pressure to the passage means and a second position coupling the passage means to the trigger valve means.   
     
     
       14. The tool set forth in claim 12 in which the safety valve means has a first position in which a limited quantity of pressurized fluid is supplied to the passage means and a second position in which the passage means is placed in open communication with the trigger valve means.   
     
     
       15. In a tool for driving fasteners into a workpiece using a fluid motor to actuate a fastener driver, a reservoir of pressurized fluid in the tool,   main valve means for controlling the application of fluid from the reservoir to the fluid motor and including a fluid control for controlling operation of the main valve means,   a passage extending to the fluid control for selectively coupling the fluid control to the reservoir and the atmosphere,   trigger valve means with an outlet coupled to the reservoir and the atmosphere in alternate positions of the trigger valve means,   safety valve means having a normal position coupling the passage to the reservoir and an operated position coupling the passage to the outlet of the trigger valve means, the safety valve means being actuated to its operated position when the tool is disposed adjacent the workpiece,   and a fluid operated valve movable between a first position placing the safety valve means in communication with the outlet of the trigger valve and second position closing off communication between the safety valve means and the outlet of the trigger valve means, said fluid operated valve having a pair of opposed fluid responsive surfaces for moving the fluid operated valve between said first and second position, a first one of said surfaces being supplied with fluid from the reservoir under the control of the trigger valve means and a second one of the fluid responsive surfaces being supplied with fluid under the control of the safety valve means.   
     
     
       16. The tool set forth in claim 15 in which the first fluid responsive surface is coupled to the outlet of the trigger valve means.   
     
     
       17. The tool set forth in claim 16 in which the safety valve means includes an additional valve which couples the second fluid responsive surface to the reservoir when the safety valve means is in its normal position and which couples the second fluid responsive surface to the atmosphere when the safety valve means is in its operated position.   
     
     
       18. The tool set forth in claim 15 in which the first and second fluid responsive surfaces are of equal area.   
     
     
       19. The tool set forth in claim 15 in which the first and second fluid responsive surfaces have differential areas. .Iadd. 20. A fastener driving device including a portable housing, fluid pressure operated fastener driving means carried by said housing for movement through successive cycles of operation each of which includes a fastener driving stroke and a return stroke, fastener magazine means carried by said housing for receiving a supply of fasteners and feeding successive fasteners into a position to be driven into a workpiece during successive fastener driving strokes of said fastener driving means, fluid pressure control means including an actuating member carried by said housing for movement from a normal inoperative position into an operative position for initiating the movement of said fastener driving means through a fastener driving stroke, a work contact responsive member carried by said housing for movement from a normal inoperative position into an operative position in response to the movement of said device into cooperating engagement with a workpiece, and a trigger member carried by said housing for manual movement from a normal inoperative position into an operative position, the improvement in combination therewith which comprises enabling means operatively associated with said members for (1) enabling movement of said trigger member into its operative position when said work contact responsive member is in its inoperative position without movement of said actuating member into its operative position, (2) enabling movement of said trigger member into its operative position when said work contact responsive member is in its operative position to effect movement of said actuating member into its operative position, and (3) enabling movement of said work contact responsive member into its operative position when said trigger member is in its operative position without movement of said actuating member into its operative position. .Iaddend. .Iadd. 21. A fastener driving device including a portable housing having a handle adapted to be manually gripped by an operator, fluid pressure operated fastener driving means carried by said housing for movement through successive cycles of operation each of which includes a fastener driving stroke and a return stroke, fastener magazine means carried by said housing for receiving a supply of fasteners and feeding successive fasteners into a position to be driven into a workpiece during successive fastener driving strokes of said fastener driving means, fluid pressure control means including an actuating member carried by said housing for reciprocating movement from a normal inoperative position into an operative position for initiating the movement of said fastener driving means through a single fastener driving stroke and from said operative position into said inoperative position for initiating the movement of said fastener driving means through a single return stroke, a work contact responsive member carried by said housing for reciprocating movement adjacent said actuating member from a normal inoperative position into an operative position in response to the movement of said device into cooperating engagement with a workpiece and from said operative position into said inoperative position in response to the movement of said device out of cooperative engagement with the workpiece and a trigger member carried by said housing adjacent said actuating member in a position to be engaged by a finger of an operator grasping said handle for pivotal movement from a normal inoperative position into an operative position in response to digital pressure and from said operative position into said inoperative position in response to the release of said digital pressure, the improvement in combination therewith which comprises enabling means operatively associated with said members for (1) enabling movement of said trigger member into its operative position when said work contact responsive member is in its inoperative position without movement of said actuating member into its operative position, (2) enabling movement of said trigger member into its operative position when said work contact responsive member is in its operative position to effect movement of said actuating member into its operative position, and (3) enabling movement of said work contact responsive member into its operative position when said trigger member is in its operative position without movement of said actuating member into its operative position. .Iaddend. .Iadd. 22. In a tool for driving fasteners into a workpiece using a pressurized fluid motor for actuating a fluid driving means, a manually actuated trigger means, a safety means actuated by placing the tool adjacent the workpiece, actuating means controlled by the trigger means and the safety means for controlling the application of pressurized fluid to the fluid motor, and a control means operatively associated with said trigger means and said safety means to prevent operation of the actuating means unless the safety means is first actuated followed by the actuation of the trigger means and to prevent operation of said actuation means upon said safety means being actuated subsequent to actuation of said trigger means. .Iaddend.