GB1239624A - - Google Patents

Abstract

1,239,624. Nailing machines. SPOTNAILS Inc. 14 May, 1969 [17 May, 1968], No. 24555/69. Heading B4C. A pneumatically actuated nailing machine comprises a piston 32 having at least one bore 39 and a valve 33 between annular chambers 19, 20, the chamber 19 receiving compressed air through a passage 18, and the chamber 20 through passages 21, 22 and a trigger valve 25, from an inlet chamber 16. The valve 33 is biased to its lowermost position, Fig. 3, by a spring 37, the chambers 19, 20 both containing compressed air. In this position a passage 34 in the valve 33<SP>1</SP> is open to the atmosphere through a passage 35, and the chamber 19 is shut off from the space above the piston 32. On raising the trigger valve 25, see Fig. 4 (not shown), the chamber 20 is shut off from the inlet chamber 16 and opened to the atmosphere at 27, thus allowing the air in the chamber 19 to raise the valve 33 so that the passage 34 abuts a seal 36 to close the passage 35. Further, the raising of the valve 33 allows the compressed air in the chamber 19 to force the piston 32 downwards causing the driving blade 38 to strike a nail 15. During the descent of the piston 32, compressed air flows through the bore(s) 39 and into an annular chamber 42 via an inlet 43. The trigger valve 25 is then released, allowing the chamber 20 to refill with compressed air to lower the valve 33, so that the space above the piston 32, which is resting on a collar 45, is open to the atmosphere through the passages 34, 35 and so that the chamber 19 is again sealed. Consequently the compressed air in the chamber 42 raises the piston 32 whilst air again leaks through the bore(s) 39 ensuring a gentle return of the piston. Air may be allowed to leak from between the housing and the rod 38 to remove excess compressed air from below the piston, and the chamber 42 may be of equal volume to the chamber 40 formed above the piston.