Control mechanism for a pneumatic tool
First Claim
1. In a pneumatic tool including a cylinder having a rear end and a front end, means for securing an implement to the cylinder at the front end, a piston in the cylinder adapted to be driven alternately forwardly and rearwardly by pressurized air, and control mechanism comprising a control body secured to the rear end of the cylinder, said body having an inlet for pressurized air and an outlet for regulated air directed toward the front end and a transverse opening communicating with said inlet and said outlet, a valve pin in said transverse opening and movable to a selected one of a plurality of positions between first and second extremes, the amount of air from said inlet to said outlet being a minimum in the first extreme and a maximum in the second extreme, means biasing said valve pin to one of the extremes, and control means for placing said valve pin in a selected one of the positions, said control means including a plurality of detent means engageable with said valve pin for retaining said control means in a condition corresponding to the selected position of said valve means.
5 Assignments
0 Petitions
Accused Products
Abstract
Control mechanism for a pneumatic hand tool which provides improved performance, speed regulation and control of the tool in air pressure ranges up to at least 116 pounds per square inch gauge (psig). A pneumatic hand tool embodying subject control mechanism includes a cylinder having an implement, such as a chisel, secured thereto and a reciprocating piston in the cylinder, the piston adapted to be driven by pressurized air into impact engagement with the front head of the cylinder, and returned to the rear cylinder end without impact. The control mechanism comprises an adjustable control valve which meters the volume of incoming pressurized air to that amount which produces desired tool operation, and an improved ball valve between the control valve and the cylinder. The control valve includes a radially movable spring-biased valve pin which cooperates with a valve seat, and a rotatable control ring in effective relation with the valve pin. The control ring has an internal spiral cam surface extending through about 90° adapted to move the valve pin from a radially outward fully opened position to a radially inward closed position where the valve pin firmly engages the valve seat. Intermediate settings of the control ring provide intermediate valve actions. The internal cam surface has a scallop configuration providing discrete valve pin detent positions between closed and fully opened positions.
40 Citations
7 Claims
- 1. In a pneumatic tool including a cylinder having a rear end and a front end, means for securing an implement to the cylinder at the front end, a piston in the cylinder adapted to be driven alternately forwardly and rearwardly by pressurized air, and control mechanism comprising a control body secured to the rear end of the cylinder, said body having an inlet for pressurized air and an outlet for regulated air directed toward the front end and a transverse opening communicating with said inlet and said outlet, a valve pin in said transverse opening and movable to a selected one of a plurality of positions between first and second extremes, the amount of air from said inlet to said outlet being a minimum in the first extreme and a maximum in the second extreme, means biasing said valve pin to one of the extremes, and control means for placing said valve pin in a selected one of the positions, said control means including a plurality of detent means engageable with said valve pin for retaining said control means in a condition corresponding to the selected position of said valve means.
Specification