Drive system

Claim 2

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, first means for supplying fluid under pressure to the front end of said first assembly, second means for supplying fluid under pressure to the front end of said second assembly, said first and second fluid supply means being communicable with a source of fluid under pressure, means for selectively communicating one of said first and second fluid supply means with said source of fluid under pressure, means interconnecting the rear ends of said assemblies, first means for sensing a predetermined condition of the piston of said first assembly, second means for sensing a predetermined position of the piston of said second assembly, and means communicable with said source of fluid under pressure for supplying fluid under pressure to the rear end of said first assembly while closing said means intercommunicating the rear ends of said assemblies responsive to said first sensing means sensing the predetermined position of the piston of said first assembly and said second sensing means not sensing the predetermined position of the piston of said second assembly.

Claim 3

A drive system according to claim 1 wherein said means for communicating the rear end of said first assembly with said source of fluid under pressure is electrically operated responsive to said sensing means.

Claim 4

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, a first fluid supply line communicating with the front end of said first assembly, a second fluid supply line communicating with the front end of said second assembly, a third fluid supply line intercommunicating the rear ends of said assemblies, said first and second fluid supply lines being communicable with a source of fluid under pressure, a valve for selectively communicating one of said first and second fluid supply lines with said source of fluid under pressure, a valve disposed in said third fluid line intercommunicating the rear ends of said assemblies, a fourth fluid line communicable with a source of fluid under pressure and the rear end of said second assembly, a valve disposed in said fourth fluid line, first means for sensing a predetermined position of the piston of said first assembly, second means for sensing a predetermined position of the piston of said second assembly, said valve in said third fluid line being normally in open position and operable to close responsive to said first sensing means sensing said predetermined position of the piston of said first assembly and said second sensing means not sensing said predetermined position of the piston of said second assembly, and said valve in said fourth fluid line being normally in the closed position and operable to open responsive to said first sensing means sensing said predeterminEd position of the piston of said first assembly and not sensing said predetermined position of the piston of said second assembly.

Claim 5

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, a first fluid supply line communicating with the front end of said first assembly, a second fluid supply line communicating with the front end of said second assembly, a third fluid supply line intercommunicating the rear ends of said assemblies, said first and second fluid supply lines being communicable with a source of fluid under pressure, a valve for selectively communicating one of said first and second fluid supply lines with said source of fluid under pressure, a valve disposed in said third fluid line intercommunicating the rear ends of said assemblies, a fourth fluid line communicable with a source of fluid under pressure and the rear end of said second assembly, a valve disposed in said fourth fluid line, first means for sensing a predetermined position of the piston of said first assembly, second means for sensing a predetermined position of the piston of said second assembly, said valve in said third fluid line being normally in open position and operable to close responsive to said first sensing means sensing said predetermined position of the piston of said first assembly and said second sensing means not sensing said predetermined position of the piston of said second assembly, and said valve in said fourth fluid line being normally in the closed position and operable to open responsive to said first sensing means sensing said predeterminEd position of the piston of said first assembly and not sensing said predetermined position of the piston of said second assembly.

Claim 6

A drive system according to claim 3, wherein said valves in said third and fourth fluid lines are electrically operated and the electrical supply line therefor includes a limit switch actuable by a predetermined movement of the piston of said first assembly.

Claim 7

A drive system according to claim 3, wherein the valves in said third and fourth fluid lines are electrically operated and the electrical supply line therefor includes a first limit switch operative responsive to said predetermined position of the piston of said first cylinder assembly, and a second limit switch operable responsive to a predetermined position of the piston of said second assembly.

Claim 8

A drive system according to claim 5, wherein said selector valve for said first and second fluid supply lines is electrically operated by said electrical supply circuit, and wherein said electrical supply circuit includes means for periodic energization thereof.

Claim 9

A drive system according to claim 3, wherein the valve in said third fluid line is normally in the open position and is electrically operable to close, and said valve in said fourth fluid line is normally in the closed position and is electrically operable to open, and said electrically operated valves are provided with an electrical supply circuit, and wherein said electrical supply circuit includes a limit switch normally in the closed position adapted to be opened responsive to the maximum forward travel of the piston of said second assembly, and a second limit switch normally in the open position adapted to close responsive to the maximum rearward travel of the piston of said first assembly.

Claim 10

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, first means supplying fluid under pressure to the front end of said first assembly, second means for supplying fluid under pressure to the front end of said second assembly, said first and second fluid supply means being communicable with a source of fluid under pressure, means for selectively communicating one of said first and second fluid supply means with said source of fluid under pressure, means intercommunicating the rear ends of said assemblies, first and second means for sensing first and second predetermined positions, respectively, of the piston of said first assembly, first and second means for sensing first and second predetermined pistons, respectively, of the piston of said second assembly, and means for selectively supplying fluid under pressure to the rear end of one of said assemblies while closing said means intercommunicating the rear ends of said assemblies responsive to said second sensing means of said one assembly not sensing the second predetermined position of the piston of said one assembly and the first sensing means of the other said assemblies sensing the first predetermined position of the piston of said other of said assemblies.

Claim 11

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, first means supplying fluid under pressure to the front end of said first assembly, second means for supplying fluid under pressure to the front end of said second assembly, said first and second fluid supply means being communicable with a source of fluid under pressure, means for selectively communicating one of said first and second fluid supply means with said source of fluid under pressure, means intercommunicating the rear ends of said assemblies, first and second means for sensing first and second predetermined positions, respectively, of the piston of said first assembly, first and second means for sensing first and second predetermined pistons, respectively, of the piston of said second assembly, and means for selectively supplying fluid under pressure to the rear end of one of said assemblies while closing said means intercommunicating the rear ends of said assemblies responsive to said second sensing means of said one assembly not sensing the second predetermined position of the piston of said one assembly and the first sensing means of the other said assemblies sensing the first predetermined position of the piston of said other of said assemblies.

Claim 12

A drive system according to claim 8, wherein said means for selectively communicating the rear ends of said assemblies with said source of fluid under pressure is electrically operated responsive to said sensing means.

Claim 13

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, a first fluid supply line communicating with the front end of said first assembly, a second fluid supply line communicating with the front end of said second assembly, a third fluid supply line intercommunicating the rear ends of said assemblies, said first and second fluid supply lines being communicable with a source of fluid under pressure, a valve for selectively communicating one of said first and second fluid supply lines with said source of fluid under pressure, first and second valves disposed in said third fluid line intercommunicating the rear ends of said assemblieS, a fourth fluid line including a valve intercommunicating said first fluid supply line and said third fluid line between said first and second valves in said third fluid line, and a fifth fluid line including a valve intercommunicating said second fluid supply line and said third fluid line between said first and second valves in said third fluid line.

Claim 14

A drive system comprising a first fluid actuated piston and cylinder assembly, a second fluid actuated piston and cylinder assembly, a first fluid supply line communicating with the front end of said first assembly, a second fluid supply line communicating with the front end of said second assembly, a third fluid supply line intercommunicating the rear ends of said assemblies, said first and second fluid supply lines being communicable with a source of fluid under pressure, a valve for selectively communicating one of said first and second fluid supply lines with said source of fluid under pressure, first and second valves disposed in said third fluid line intercommunicating the rear ends of said assemblieS, a fourth fluid line including a valve intercommunicating said first fluid supply line and said third fluid line between said first and second valves in said third fluid line, and a fifth fluid line including a valve intercommunicating said second fluid supply line and said third fluid line between said first and second valves in said third fluid line.

Claim 15

A drive system according to claim 10, wherein said first and second valves disposed in said third fluid line normally are opened and are operable to close selectively responsive to predetermined conditions of said assemblies, and said valves in said fourth and fifth fluid lines normally are closed and are operative to open selectively responsive to said predetermined conditions.

Claim 16

A drive system according to claim 10, including first means for sensing a first set of predetermined positions of the pistons of said assemblies and second means for sensing a second set of predetermined positions of the pistons of said assemblies, and wherein said first valve of said third line is adapted to close and said valve in said fourth line is adapted to open responsive to said first sensing means, and said second valve of said third fluid line is adapted to close and said valve of said fifth fluid line is adapted to open responsive to said second sensing means.

Claim 17

A drive system according to claim 10, including a first means for sensing a first predetermined position of the piston of said first assembly, second means for sensing a second predetermined position of the piston of said first assembly, a third means for sensing a first predetermined position of the piston of said second assembly and a fourth means for sensing a second predetermined position of the piston of said second assembly, and wherein said first valve in said third fluid line normally is opened and is adapted to close responsive to said second and third sensing means, said valve in said fourth fluid line normally is closed and is adapted to open responsive to said second and third sensing means, said second valve of said third fluid line normally is open and is adapted to close responsive to said first and fourth sensing means, and said valve in said fifth fluid line normally is closed and is adapted to open responsive to said first and fourth sensing means.

Claim 18

A drive system according to claim 10, wherein said valve in said third, fourth and fifth fluid lines are electrically operated and the electrical supply circuit thereof includes limit switches actuable by predetermined movements of the pistons of said assemblies.

Claim 19

A drive system according to claim 10, wherein said valves in said third fluid line normally are open and are electrically operable to close, said valves in said fourth and fifth fluid lines are normally closed and are electrically operable to open, said first valve of said third fluid line and said valve in said fourth fluid line are provided with a first electrical circuit, said second valve of said third fluid line and said valve of said fifth fluid line are provided with a second electrical circuit, and wherein said first electrical supply circuit includes a first limit switch normally in the closed position adapted to be opened responsive to the maximum forward travel of the piston of said second assembly and a second limit switch normally in the open position adapted to close responsive to the maximum rearward travel of the piston of said first assembly and said second electrical supply system includes a first limit switch normally in the open position adapted to be closed responsive to the maximum rearward travel of the piston of said second assembly and a second limit switch normally in the closed position adapted to be opened responsive to the maximum forward travel of the piston of said first assembly.

Claim 20

A drive system according to claim 15, wherein said selector valve for said first and second fluid supply lines is electrically operated by one of said first and second electrical supply circuits and wherein Means are provided for alternately energizing said first and second electrical supply circuits for predetermined periods of time.