Compression actuated tool for driving fasteners

• US 5,429,291 A
• Filed: 11/04/1994
• Issued: 07/04/1995
• Est. Priority Date: 11/05/1993
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Thompson, William J.
• Primary Examiner(s): Smith, Scott A.
• Application Number:
  US08/334,201
• Time in Patent Office: 242 Days
• Field of Search: 227/9, 227/10, 227/11
• US Class Current: 227/10
• CPC Class Codes: B25C 1/14 acting on an intermediate plunger or anvil pistols for slaughtering or stunning animals A22B3/02
• CPC Class Codes: B25C 1/143 trigger operated
• CPC Class Codes: B25C 1/18 Details and accessories, e.g. splinter guards, spall minimisers
• CPC Class Codes: B25C 1/186 for cartridges or pellets
• CPC Class Codes: B25C 1/188 Arrangements at the forward end of the barrel, e.g. splinter guards, spall minimisers, safety arrangements, silencers, bolt retainers

Abstract

This invention relates to an impact actuated tool for driving a fastener by an explosive charge, particularly a tool having a housing with a barrel axially slidably mounted within the front end. A nosepiece is fixed to the front of the barrel with a muzzle at its front end for receiving a fastening element that is to be secured in a ceiling or the like. A piston is slidably mounted within the bore in the barrel. The barrel is biased forwardly in the firing direction. At the rear of the tool a handle engages a firing pin which is slidably mounted within the rear end of the bore. The firing pin is biased rearwardly towards the back end of the tool. One embodiment of the tool includes a ball lock safety device to allow discharge only when the muzzle of the tool is pointed in an upward direction. The tool is fired by impacting the nosepiece against a surface to effect displacement of the barrel and firing pin against their respective biasing springs.

Claims

1. In an explosive actuated tool for driving a fastener into a workpiece, a firing mechanism comprising:

a housing having a longitudinal bore extending therethrough, one end of said bore facing in the driving direction of said tool;

a breech block affixed to said housing bore at said one end;

a sleeve slidable longitudinally within said housing bore;

a firing pin slidable longitudinally within said sleeve and through said breech block;

a return spring biasing said sleeve and said firing pin longitudinally away from said one end;

a cocking spring within said sleeve for biasing the firing pin longitudinally toward said one end;

means for preventing said firing pin from exiting the end of said sleeve facing said one end;

handle means for moving said sleeve longitudinally within said housing bore, compressing both said return and said cocking springs;

sear means for preventing movement of said firing pin toward said breech block during the compression of said return and cocking springs; and

means on said sleeve for contacting said sear means near the end of the compression of said return and cocking springs as said sleeve is moved longitudinally within said housing bore, thereby releasing said sear means from preventing movement of said firing pin and permitting said cocking spring to impel said firing pin forcibly into said breech block.

2. The firing mechanism of claim 1 wherein said breech block includes an internal bore partially extending through said breech block and a passage extending from said breech block bore through the remainder of said breech block into a firing chamber, and said firing pin includes a tip shaped to fit within and through said passage and a flange shaped to slidably fit within said breech block bore but not within said passage.

3. The firing mechanism of claim 1 wherein said breech block further includes a shoulder extending transversely of said housing bore, and said sear means has a transverse surface which abuts said transverse shoulder until moved out of contact therewith by said sleeve.

4. The firing mechanism of claim 3 wherein said firing pin includes a radially extending slot and said sear means comprises a pawl slidable in said slot and a spring for biasing said pawl radially outwardly from the longitudinal axis of said firing pin, said pawl including a cam surface which coacts with an edge of said sleeve to cam said pawl into said slot, whereupon said transverse surface of said sear means moves out of contact with said breech block transverse shoulder.

5. The firing mechanism of claim 2 wherein said housing bore, said handle, said sleeve, said firing pin, and said breech block bore and passage are all coaxially aligned.

6. A tool as in claim 1 wherein said means for preventing said firing pin from exiting the end of said sleeve comprises a radially outwardly directed flange on said firing pin and a radially inwardly flange at the end of said sleeve facing said forward end, said flanges presenting confronting shoulders which are biased into contact by said cocking spring.

7. A tool as in claim 1 further comprising:

a barrel slidably mounted within the housing; and

a piston slidably mounted within the barrel, wherein a biasing means operationally associated with the piston returns the piston to its resting orientation after firing the tool.

8. A tool as in claim 7 wherein a plurality of apertures are formed in said barrel, said apertures being substantially closed at their outer ends by said housing to form chambers which allow the combustion gases to expand into the said expansion chambers.

9. A tool as in claim 1 further comprising a safety means to prevent axial movement of the firing pin when the muzzle of the tool is oriented in a downward direction.

10. An explosive actuated tool for driving a fastener into a workpiece comprising:

a housing having first and second longitudinal bores therein separated by a firing chamber, said first bore being at a forward end of said tool and said second bore being at a rearward end of said tool;

a barrel slidably received in said first bore, said barrel having a muzzle at one end for receiving said fastener and a breech at the other end, said breech end being adjacent to said firing chamber;

means for biasing said barrel away from said firing chamber;

a blind slot in the external surface of said barrel;

means insertable through said housing and into said slot for limiting movement of said barrel in said housing;

strip means for carrying a plurality of cartridges;

means for holding, guiding and indexing said strip means into said firing chamber such that the cartridges are sequentially fed into alignment with said barrel breech;

a firing mechanism in said second bore, said firing mechanism comprising;

a breech block affixed to said second bore adjacent said firing chamber;

a sleeve slidable longitudinally within said second bore;

a firing pin slidable longitudinally within said sleeve and through said breech block;

a return spring biasing said sleeve and said firing pin longitudinally toward said tool rearward end;

a cocking spring within said sleeve for biasing the firing pin longitudinally toward said tool forward end;

means for preventing said firing pin from exiting the end of said sleeve facing said forward end;

handle means for moving said sleeve longitudinally within said second bore, compressing both said return and said cocking springs, said handle means extending from the rearward end of said tool;

sear means for preventing movement of said firing pin toward said breech block during the compression of said return and cocking springs; and

means on said sleeve for contacting said sear means near the end of the compression of said return and cocking springs as said sleeve is moved longitudinally within said housing bore, thereby releasing said sear means from preventing movement of said firing pin and permitting said cocking spring to impel said firing pin forcibly into said breech block.

11. The tool of claim 10 wherein said breech block includes an internal bore partially extending through said breech block and a passage extending from said breech block bore through the remainder of said breech block into said firing chamber, and said firing pin includes a tip shaped to fit within and through said passage and a flange shaped to slidably fit within said breech block bore but not within said passage.

12. The tool of claim 10 wherein said breech block further includes a shoulder extending transversely of said housing bore, and said sear means has a transverse surface which abuts said transverse shoulder until moved out of contact therewith by said sleeve.

13. The tool of claim 12 wherein said firing pin includes a radially extending slot and said sear means comprises a pawl slidable in said slot and a spring for biasing said pawl radially outwardly from the longitudinal axis of said firing pin, said pawl including a cam surface which coacts with an edge of said sleeve to cam said pawl into said slot, whereupon said transverse surface of said sear means moves out of contact with said breech block transverse shoulder.

14. The tool of claim 11 wherein said second bore, said handle, said sleeve, said firing pin, and said breech block bore and passage are all coaxially aligned.

15. The tool of claim 10 wherein said limiting means comprises a wedge, said wedge being biased by a spring into said slot, and said wedge and said wedge biasing spring being confined within an aperture in said housing by a threaded screw.

16. A tool as in claim 10 wherein said means for preventing said firing pin from exiting the end of said sleeve comprises a radially outwardly directed flange on said firing pin and a radially inwardly flange at the end of said sleeve facing said forward end, said flanges presenting confronting shoulders which are biased into contact by said cocking spring.

17. A tool as in claim 10 wherein a plurality of apertures are formed in said barrel, said apertures being substantially closed at their outer ends by said housing to form chambers which allow the combustion gases to expand into the said expansion chambers.

18. A tool as in claim 17 wherein the apertures are sized and selectively located such that the most rearward aperture is at a location wherein said combustion gases are not permitted to expand thereinto until the fastener is completely driven into the workpiece.

19. A tool as in claim 17 wherein the apertures are sized and selectively located such that the apertures reflect acoustic waves in order to reduce noise emitted by the tool.

20. A tool as in claim 10 further comprising a safety means to prevent axial movement of the firing pin when the muzzle of the tool is oriented in a downward direction.

21. An explosive actuated tool for driving a fastener into a workpiece comprising:

a housing having first and second longitudinal bores therein separated by a firing chamber, said first bore being at a forward end of said tool and said second bore being at a rearward end of said tool;

a barrel slidably received in said first bore, said barrel having a muzzle at one end for receiving said fastener and a breech at the other end, said breech end being adjacent to said firing chamber;

means for biasing said barrel away from said firing chamber;

a blind slot in the external surface of said barrel;

means insertable through said housing and into said slot for limiting movement of said barrel in said housing;

strip means for carrying a plurality of cartridges;

means for holding, guiding and indexing said strip means into said firing chamber such that the cartridges are sequentially fed into alignment with said barrel breech;

a firing mechanism in said second bore, said firing mechanism comprising;

a sleeve slidable longitudinally within said second bore;

a firing pin slidable longitudinally within said sleeve;

a return spring biasing said firing pin longitudinally toward said tool rearward end;

a cocking spring within said sleeve for biasing the firing pin longitudinally toward said tool forward end;

handle means for moving said sleeve longitudinally within said second bore, compressing both said return and said cocking springs, said handle means extending from the rearward end of said tool;

sear means for preventing movement of said firing pin toward said tool forward end during compression of said return and compression springs; and

means on said sleeve for contacting said sear means near the end of the compression of said return and said cocking springs as said sleeve is moved longitudinally within said housing bore, thereby releasing said sear means from preventing movement of said firing pin and permitting said firing pin to move toward said tool forward end.

22. A tool as in claim 21 wherein a plurality of apertures are formed in said barrel, said apertures being substantially closed at their outer ends by said housing to form chambers which allow the combustion gases to expand into the said expansion chambers.

23. A tool as in claim 22 wherein the apertures are sized and selectively located such that the most rearward aperture is at a location wherein said combustion gases are not permitted to expand thereinto until the fastener is completely driven into the workpiece.

24. A tool as in claim 22 wherein the apertures are sized and selectively located such that the apertures reflect acoustic waves in order to reduce noise emitted by the tool.

25. A tool as in claim 21 further comprising a means to prevent axial movement of the firing pin when the muzzle of the tool is oriented in a downward direction.