SLEEVE FOR A PNEUMATIC FASTENER-DRIVING TOOL

• US 20130206811A1
• Filed: 02/10/2012
• Published: 08/15/2013
• Est. Priority Date: 02/10/2012
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Zhao, Hanxin, Moore, Stephen P.
• Granted Patent: US 9,844,864 B2
• Time in Patent Office: Days
• US Class Current: 227/130
• CPC Class Codes: B25C 1/041 with fixed main cylinder

Abstract

A fastener driving tool including a housing enclosing a cylinder having a lower end with a resilient bumper, a return air chamber in communication with the lower end of the cylinder and a piston dimensioned for reciprocation within the cylinder to impact the bumper and having a driver blade depending therefrom. At least one inlet opening is in communication with the return air chamber and at least one outlet opening is disposed in the cylinder and spaced from the at least one inlet opening. The at least outlet opening is in communication with the return air chamber and aligned with the piston so that each outlet opening is closed by the piston to seal the cylinder as the piston impacts the bumper and traps a residual volume of air in the cylinder below the piston to damp impact of the piston upon the bumper.

Claims

1. A fastener driving tool comprising:

a housing enclosing a cylinder provided with a resilient bumper;

a return air chamber in communication with said cylinder;

a piston dimensioned for reciprocation within said cylinder to impact said bumper, said piston having a driver blade depending therefrom;

at least one inlet opening disposed in said cylinder and in communication with said return air chamber; and

at least one outlet opening disposed in said cylinder and spaced from said at least one inlet opening, said at least one outlet opening being in communication with said return air chamber and aligned with said piston, each said outlet opening being closed by said piston to seal said cylinder when said piston impacts said bumper, wherein said at least one outlet opening configured such that upon said piston impacting said bumper and closing said at least one outlet opening, a residual volume of air is trapped in said sealed cylinder below said piston to damp impact of said piston upon said bumper.

2. The tool of claim 1 further including a plurality of said inlet openings spaced about said cylinder.

3. The tool of claim 1 further including a plurality of said outlet openings spaced about said cylinder.

4. The tool of claim 1, wherein said piston includes at least one seal ring that forms a seal between said piston and said cylinder.

5. The tool of claim 4, wherein said at least one seal ring is made with a metal or a polymer.

6. The tool of claim 1, wherein said piston includes two spaced seal rings each forming a seal between said piston and said cylinder.

7. The tool of claim 1 wherein said bumper is provided with a generally normal profile of an upper exterior dimension which increases bumper volume.

8. The tool of claim 1 further including a damping formation extending from a lower side of said piston.

9. The tool of claim 8 wherein said damping formation has a shape which complements a profile of said bumper.

10. The tool of claim 1, wherein said piston has a height that is greater than a diameter of said at least one outlet opening.

11. A fastener driving tool comprising:

a cylinder having a resilient bumper;

a return air chamber in communication with said cylinder;

a piston dimensioned for reciprocation within said cylinder and having a driver blade depending therefrom and a pair of spaced seal rings;

a plurality of inlet openings defined by said cylinder, each of said inlet openings being in communication with said return air chamber; and

a plurality of outlet openings defined by said cylinder and spaced from said plurality of inlet openings, said plurality of outlet openings each having a height approximately less than or equal to a height of said piston, said piston configured to block each of said plurality of outlet openings to seal said cylinder when said piston impacts said bumper and retains a residual volume of air for providing damping to said piston, said plurality of outlet openings each having a height less than or equal to a distance between said rings so that at least one of an upper seal ring seals an upper margin of each of said plurality of outlet openings, and a lower seal ring seals a lower margin of each of said plurality of outlet openings when said piston impacts said bumper.

12. The tool of claim 11 wherein each of said plurality of inlet and outlet openings are disposed along a periphery of said cylinder.

13. The tool of claim 11 wherein said bumper is provided with a generally normal profile of an upper exterior dimension which increases bumper volume.

14. The tool of claim 11 further including a damping formation depending from a lower side of said piston which complements an opposing profile of said bumper.

15. A method for generating a residual air volume in a pneumatic fastening tool including a cylinder provided with a resilient bumper, a piston dimensioned for reciprocation within the cylinder and having a driver blade depending therefrom, and at least one outlet opening, said method comprising:

positioning the at least one outlet opening to correspond with a position of the piston when it impacts the bumper, wherein each said outlet opening is blocked by said piston to seal the cylinder upon said impact of the bumper; and

reducing a volume defined between the piston and the lower end of the cylinder by increasing at least one of piston profile and bumper profile.

16. The method of claim 15 further including providing said piston with at least one seal ring configured to maintain a sealing relationship with the cylinder above the at least one outlet opening to maintain a seal as the piston impacts, compresses and returns from the bumper.

17. The method of claim 15 further including providing said piston with at least one seal ring configured to maintain a sealing relationship below the at least one opening to maintain a seal as the piston impacts, compresses and returns from the bumper.

18. The method of claim 15 further including providing said piston with at least one first seal ring configured to maintain a sealing relationship above the at least one outlet opening to maintain a seal as the piston impacts, compresses and returns from the bumper, and at least one second seal ring constructed and arranged to maintain a sealing relationship below the at least one outlet opening to maintain a seal as the piston impacts, compresses and returns from the bumper.

19. The method of claim 15 wherein said at least one outlet opening is positioned above or adjacent to the bumper.