Auxiliary tool control circuit

Claim 2

A control circuit for an auxiliary tool adapted to be operatively associated with control means for another tool having a source of operating fluid and means for delivering the operating fluid under pressure, the control circuit including: a first fluid conduit means for connecting fluid delivery means to the control means for the other tool, the pressure level in said first fluid conduit means being influenced by the operative state of the control means for the other tool; pilot operated valve means in said first fluid conduit means; second fluid conduit means from said pilot operated valve means to the inlet of an auxiliary tool to be powered; third fluid conduit means for returning fluid from the discharge from an auxiliary tool to be powered to a reservoir; said pilot operated valve means having a first position interconnecting the parts of said first fluid conduit means upstream and downstream of said pilot operated valve means and connecting said second fluid conduit means to said third fluid conduit means, and said pilot operated valve means having a second position connecting said first fluid conduit means to said second fluid conduit means to deliver operating fluid to the auxiliary tool; selectively operable control means for arming said pilot valve means for switching from the first position thereof to the second position; and means responsive to the pressure level of fluid in said first fluid conduit means downstream of said pilot valve means for delivering an operating signal to said pilot valve means and switching said pilot valve means between said first and second positions thereof in the armed state of said pilot valve means.

Claim 3

A control circuit as in claim 1 wherein: said selectively operable control means includes a control valve having first and second positions; and wherein said means for delivering the operating signal to the pilot valve means includes fourth fluid conduit means from said control valve to said pilot valve means, and fifth fluid conduit means from said first fluid conduit means to said control valve means; and further including sixth fluid conduit means from said third fluid conduit means to said control valve means; said control valve in the first position connecting said fourth and sixth fluid conduit means, and said control valve in the second position connecting said fourth and fifth conduit means, said second position of said control valve being the position for arming said pilot valve means.

Claim 4

A control circuit as in claim 2 including: check valve means in said first fluid conduit means between said pilot operated valve means and said fifth fluid conduit means.

Claim 5

A control circuit as in claim 2 including: seventh fluid conduit means from a point in said first fluid conduit means upstream of said pilot operated valve means to said fifth fluid conduit meanS; and adjustable flow control means in said seventh fluid conduit means for compensation of leakage from said first fluid conduit means downstream of said pilot operated valve means.

Claim 6

A control circuit as in claim 2 wherein: the pressure level in said first fluid conduit means increases in response to actuation of the control means for the other tool to an active state whereby said operating signal is delivered via said fifth fluid conduit means, the second position of said control valve and said fourth fluid conduit means to operate said pilot valve means and operating fluid is delivered via said first fluid conduit means, the second position of said pilot valve means, and said second fluid conduit means to the auxiliary tool.

Claim 7

A control circuit as in claim 5 whrein: said pilot operated valve means returns to the first position thereof to terminate operation of the auxiliary tool upon reduction in pressure in said first fluid conduit means below a predetermined value with said control valve in the second position thereof.

Claim 8

A control circuit as in claim 6 wherein: the pressure in said first fluid conduit means downstream of said check valve is insufficient to actuate the another tool when the auxiliary tool is operative.

Claim 9

A control circuit for an auxiliary tool adapted to be operatively associated with control means for another tool mounted on a vehicle and having hydraulic actuating means, said vehicle having a source of operating hydraulic fluid, pump means for delivering the operating fluid under pressure to the hydraulic actuating means for the another tool, and control means for the another tool having at least one active position for delivering hydraulic fluid to said actuating means and a neutral position for returning hydraulic fluid to a reservoir, the control circuit including: first hydraulic conduit means for connecting the pump means to the control means for the another tool, the fluid in said first conduit means being at an elevated pressure level when said control means for the another tool is in an active position and a load is imposed on hydraulic actuating means for the another tool, and the pressure of fluid in said first conduit means being at a lower pressue level when the control means for the another tool is in a neutral position; pilot operated valve means in said first conduit means; second hydraulic conduit means from said pilot valve means to the inlet of an auxiliary tool to be powered; third hydraulic conduit means for returning hydraulic fluid from the discharge of the auxiliary tool to a reservoir; said pilot operated valve means having a first position interconnecting the parts of said first conduit means upstream and downstream of said pilot valve means to provide fluid communication from the pump means to the control means for the another tool and connecting said second conduit means to said third conduit means to vent said third conduit means to the reservoir, and said pilot valve means having a second position connecting said first fluid conduit means to said second conduit means to deliver operating fluid to the auxiliary tool; selectively operable control means including a control valve having first and second positions; fourth fluid conduit means from said control valve to said pilot operated valve means for delivering an operating signal to switch said pilot operated valve means between said first and second positions thereof; fifth hydraulic conduit means from said first conduit means to said control valve; and sixth hydraulic conduit means from said third conduit means to said control valve; said control valve in the first position interconnecting said fourth and sixth conduit means and dead ending said fifth conduit means, and said control valve in the second position interconnecting said fourth and fifth conduit means to deliver the operating signal to said pilot operated valve means and dead ending said sixth conduit means.

Claim 10

A control circuit for an auxiliary tool adapted to be operatively associated with control means for another tool mounted on a vehicle and having hydraulic actuating means, said vehicle having a source of operating hydraulic fluid, pump means for delivering the operating fluid under pressure to the hydraulic actuating means for the another tool, and control means for the another tool having at least one active position for delivering hydraulic fluid to said actuating means and a neutral position for returning hydraulic fluid to a reservoir, the control circuit including: first hydraulic conduit means for connecting the pump means to the control means for the another tool, the fluid in said first conduit means being at an elevated pressure level when said control means for the another tool is in an active position and a load is imposed on hydraulic actuating means for the another tool, and the pressure of fluid in said first conduit means being at a lower pressue level when the control means for the another tool is in a neutral position; pilot operated valve means in said first conduit means; second hydraulic conduit means from said pilot valve means to the inlet of an auxiliary tool to be powered; third hydraulic conduit means for returning hydraulic fluid from the discharge of the auxiliary tool to a reservoir; said pilot operated valve means having a first position interconnecting the parts of said first conduit means upstream and downstream of said pilot valve means to provide fluid communication from the pump means to the control means for the another tool and connecting said second conduit means to said third conduit means to vent said third conduit means to the reservoir, and said pilot valve means having a second position connecting said first fluid conduit means to said second conduit means to deliver operating fluid to the auxiliary tool; selectively operable control means including a control valve having first and second positions; fourth fluid conduit means from said control valve to said pilot operated valve means for delivering an operating signal to switch said pilot operated valve means between said first and second positions thereof; fifth hydraulic conduit means from said first conduit means to said control valve; and sixth hydraulic conduit means from said third conduit means to said control valve; said control valve in the first position interconnecting said fourth and sixth conduit means and dead ending said fifth conduit means, and said control valve in the second position interconnecting said fourth and fifth conduit means to deliver the operating signal to said pilot operated valve means and dead ending said sixth conduit means.

Claim 11

A control cIrcuit as in claim 8 including: check valve means in said first fluid conduit means between said pilot operated valve means and said fifth fluid conduit means.

Claim 12

A control circuit as in claim 9 including: seventh hydraulic conduit means from a point in said first conduit means upstream of said pilot operated valve means to said fifth conduit means; and adjustable flow control means in said seventh conduit means for compensation of leakage from said first fluid conduit means downstream of said pilot operated valve means.

Claim 13

A control circuit as in claim 9 wherein: the pressure level in said first conduit means increases in response to actuation of the control means for the other tool to an active position whereby said operating signal is delivered via said fifth fluid conduit means, the second position of said control valve and said fourth fluid conduit means to operate said pilot valve means and operating fluid is delivered via said first conduit means, the second position of said pilot valve means, and said second conduit means to the auxiliary tool.

Claim 14

A control circuit as in claim 11 wherein: said pilot operated valve means returns to the first position thereof to terminate operation of the auxiliary tool upon reduction in pressure in said first conduit means below a predetermined value with said control valve in the second position thereof.

Claim 15

A control circuit for an auxiliary tool as in claim 12 wherein: the pressure in said first conduit means downstream of said check valve is inadequate to power the hydraulic actuators for the another tool when the auxiliary tool is operative.

Claim 16

A control circuit as in claim 8 including: shut off valve means in said first conduit means downstream of the connection with said fifth conduit means.