Fail-safe limit switch stopping system for air motor

Claim 2

In a pneumatic powered which system, a control circuit comprising: a source of pneumatic fluid; pneumatic power fluid and pneumatic control fluid supplies derived from said source of pneumatic fluid; a pneumatic motor operated by said pneumatic power fluid; pneumatic limit switches operated by said pneumatic control fluid which limit the operation of the winch; and means responsive to a lack of pneumatic control fluid which stop the operation of the winch; said means comprising normally closed valves placed in the pneumatic power fluid lines.

Claim 3

A pneumatic powered winch as in claim 1 wherein said normally closed valves are held open by said pneumatic control fluid.

Claim 4

A pneumatic motor control system comprising: a source of fluid; a pneumatic motor operated by said pneumatic fluid; a plurality of normally closed valves in the fluid lines leading to said motor; a plurality of normally open valves in parallel with said normally closed valves, the output from said normally open valves being used to open certain of said normally closed valves; normally closed cam-opened valves in parallel with said normally closed valves the output from which is used to close said normally open valves; and normally closed manually opened valves in parallel with said normally closed valves the output from which is used to open the others of said normally closed valves to thereby control the direction of operation of the motor.

Claim 5

A pneumatic motor control system comprising: a source of fluid; a pneumatic motor operated by said pneumatic fluid; a plurality of normally closed valves in the fluid lines leading to said motor; a plurality of normally open valves in parallel with said normally closed valves, the output from said normally open valves being used to open certain of said normally closed valves; normally closed cam-opened valves in parallel with said normally closed valves the output from which is used to close said normally open valves; and normally closed manually opened valves in parallel with said normally closed valves the output from which is used to open the others of said normally closed valves to thereby control the direction of operation of the motor.

Claim 6

A fluid motor control system comprising: a source of pressurized fluid; a fluid motor connected to said source to be driven by said pressurized fluid; a first group of fluid actuated valves connected by fluid lines to said source and said motor to control the flow of fluid to said motor; a second group of fluid actuated valves connected by fluid lines to said source and said motor in parallel with said first group of valves; a bypass fluid line interconnecting said parallel lines at a point intermediate two of the valves in each of said groups; a pair of manually operated valves each of which is connected to admit control fluid to one of the valves in said first group of fluid actuated valves, to control the flow of fluid to said motor; a pair of fluid actuated valves each of which is connected to provide control fluid to one of the valves in said second group of fluid actuated valves; a pair of cam actuated valves, each of which admits control fluid to one of said pair of fluid actuated valves, said cams being driven by said motor; and means connecting all of said valves to the source of pressurized fluid; said first and said second groups of valves being of the normally closed type and said pair of fluid actuated valves and said pair of cam actuated valves being of the normally open type; said valves being positioned such that a loss of pressure in one of the control fluid lines allows its associated normally closed valve to close, thereby stopping the operation of the fluid motor.

Claim 7

A fluid motor control system comprising: a source of pressurized fluid; a fluid motor connected to said source to be driven by said pressurized fluid; a first group of fluid actuated valves connected by fluid lines to said source and said motor to control the flow of fluid to said motor; a second group of fluid actuated valves connected by fluid lines to said source and said motor in parallel with said first group of valves; a bypass fluid line interconnecting said parallel lines at a point intermediate two of the valves in each of said groups; a pair of manually operated valves each of which is connected to admit control fluid to one of the valves in said first group of fluid actuated valves, to control the flow of fluid to said motor; a pair of fluid actuated valves each of which is connected to provide control fluid to one of the valves in said second group of fluid actuated valves; a pair of cam actuated valves, each of which admits control fluid to one of said pair of fluid actuated valves, said cams being driven by said motor; and means connecting all of said valves to the source of pressurized fluid; said first and said second groups of valves being of the normally closed type and said pair of fluid actuated valves and said pair of cam actuated valves being of the normally open type; said valves being positioned such that a loss of pressure in one of the control fluid lines allows its associated normally closed valve to close, thereby stopping the operation of the fluid motor.