Hydraulic operating mechanism for a rotary chuck

Claim 2

In hydraulic chuck operating mechanism, the combination of a swivel coupling with stationary and operationally turning companion parts, of which the turning part provides a cylinder with a piston defining therein a chuck-closing cylinder side; a conduit, including a port in said coupling leading to said cylinder side, for passing hydraulic fluid under pressure to said cylinder side, with said port crossing said coupling parts; port sealing means in said coupling at the port crossing; a check valve in said conduit dividing the same into first and second conduit sections of which said second section extends from said valve to said cylinder side, with said valve being normally closed to block fluid flow from said cylinder side, and being opened by fluid in said first conduit section under a pressure in excess of that of fluid in said cylinder side to introduce fluid into said cylinder side and opened by piston means to release fluid from said cylinder side; and a fluid pressure control for said cylinder side, providing a bypass in said conduit around said check valve, a second valve in said bypass forming part of the latter when open, a constriction in said bypass, and fluid pressure responsive means operatively associated with said second valve and having opposite faces exposed to fluid in said bypass on opposite sides, respectively, of said constriction to open and close said second valve when the pressure of hydraulic fluid in said second conduit section is within a certain range and is above said range, respectively, with said range being from a pressure at least equal to, to a pressure of predetermined excess over, the pressure of hydraulic fluid in said first conduit section.

Claim 3

The combination in hydraulic chuck operating mechanism as in claim 1, in which said second valve is a secondary check valve in said bypass between said constriction and second conduit section and being normally spring-closed to block fluid flow from said cylinder side, and said fluid pressure responsive means is a slidable stepped plunger with larger and smaller ends exposed to hydraulic fluid in said bypass between said first conduit section and constriction and between said constriction and second check valve, respectively, with said plunger being moved into advance and retract positions when the total pressure of fluid on said larger plunger end is greater and smaller, respectively, than the total pressure of fluid on said smaller plunger end, and said plunger in its advance and retract positions opening said secondary check valve and permitting its closure, respectively.

Claim 4

The combination in hydraulic chuck operating mechanism as in claim 2, in which there is further provided a reservoir in said bypass between said constriction and said secondary check valve, and said smaller plunger end is exposed to and forms part of said reservoir.

Claim 5

In hydraulic chuck operating mechanism, the combination of a swivel coupling with stationary and operationally turning companion parts, of which the turning part provides a cylinder with a piston defining therein first and second cylinder sides; first and second conduits, including first and second ports, respectively, in said coupling, with said first and second ports leading to said first and second cylinder sides, respectively, and crossing said coupling parts, and said conduits being adapted for connection with a valve to admit hydraulic fluid under pressure to either conduit and simultaneously vent the other conduit; port sealing means in said coupling at the port crossings; a first check valve in said first conduiT normally closed to block fluid flow from said first cylinder side, and dividing said first conduit into first and second conduit sections of which said second section extends from said check valve to said first cylinder side, with said first check valve being opened by fluid in said first conduit section under a pressure in excess of that of fluid in said second conduit section; a second slidable piston with opposite ends exposed to hydraulic fluid in said first conduit section and in said second conduit, respectively, with said second piston being by hydrauic fluid under pressure in said first conduit section and in said second conduit moved into first and second positions, respectively, in which to permit closure of said check valve and to open the same, respectively; and a fluid pressure control for said first cylinder side, providing a bypass in said first conduit around said check valve, a second valve in said bypass forming part of the latter when open, a constriction in said bypass, and fluid pressure responsive means operatively associated with said second valve and having opposite faces exposed to fluid in said bypass on opposite sides, respectively, of said constriction to open and close said second valve when the pressure of hydraulic fluid in said second conduit section is within a certain range and is above said range, respectively, with said range being from a pressure at least equal to, to a pressure of predetermined excess over, the pressure of hydraulic fluid in said first conduit section.

Claim 6

In hydraulic chuck operating mechanism, the combination of a swivel coupling with stationary and operationally turning companion parts, of which the turning part provides a cylinder with a piston defining therein first and second cylinder sides; first and second conduits, including first and second ports, respectively, in said coupling, with said first and second ports leading to said first and second cylinder sides, respectively, and crossing said coupling parts, and said conduits being adapted for connection with a valve to admit hydraulic fluid under pressure to either conduit and simultaneously vent the other conduit; port sealing means in said coupling at the port crossings; a first check valve in said first conduiT normally closed to block fluid flow from said first cylinder side, and dividing said first conduit into first and second conduit sections of which said second section extends from said check valve to said first cylinder side, with said first check valve being opened by fluid in said first conduit section under a pressure in excess of that of fluid in said second conduit section; a second slidable piston with opposite ends exposed to hydraulic fluid in said first conduit section and in said second conduit, respectively, with said second piston being by hydrauic fluid under pressure in said first conduit section and in said second conduit moved into first and second positions, respectively, in which to permit closure of said check valve and to open the same, respectively; and a fluid pressure control for said first cylinder side, providing a bypass in said first conduit around said check valve, a second valve in said bypass forming part of the latter when open, a constriction in said bypass, and fluid pressure responsive means operatively associated with said second valve and having opposite faces exposed to fluid in said bypass on opposite sides, respectively, of said constriction to open and close said second valve when the pressure of hydraulic fluid in said second conduit section is within a certain range and is above said range, respectively, with said range being from a pressure at least equal to, to a pressure of predetermined excess over, the pressure of hydraulic fluid in said first conduit section.

Claim 7

The combination in hydraulic chuck operating mechanism as in claim 4, in which there is further provided a second check valve in said second conduit normally closed to block fluid flow from said second cylinder side and dividing said second conduit into third and fourth conduit sections of which said fourth section extends from said second check valve to said second cylinder side, with said second check valve being opened by fluid in said third conduit section under a pressure in excess of that of fluid in said fourth conduit section, and a third slidable piston with opposite ends exposed to hydraulic fluid in said first conduit and in said third conduit section, respectively, with said third piston being by hydraulic fluid under pressure in said third conduit section and in said first conduit moved into first and second positions, respectively, in which to permit closure of said second check valve and to open the same, respectively; and another fluid pressure control for said second cylinder side, providing a second bypass in said second conduit around said second check valve, a third valve in said second bypass forming part of the latter when open, a second constriction in said second bypass, and fluid pressure responsive means operatively associated with said third valve and having opposite faces exposed to fluid in said second bypass on opposite sides, respectively, of said second constriction to open and close said third valve when the pressure of hydraulic fluid in said fourth conduit section is within a certain range and is above said range, respectively, with said range being from a pressure at least equal to, to a pressure of a predetermined excess over, the pressure of hydraulic fluid in said third conduit section.