Hydraulic system for laundry flatwork ironer

In a drive system for a laundry flatwork ironer having a plurality of rollers for ironing the flatwork and advancing it through the ironer, the combination of:

• a hydraulic motor for driving the rollers;
• a pump for supplying pressurized fluid to the motor to drive the motor, said pump having an inlet port, an outlet port and a pressure sensing port, said pump being operable to maintain a predetermined pressure differential between its outlet port and its pressure sensing port;
• means providing a low pressure return passageway for fluid discharged by said hydraulic motor;
• valve means operatively connected to control the flow of fluid from said pump to said hydraulic motor and from said motor to said low pressure return passageway;
• and a pump pressure control valve operatively connected to said pressure sensing port of the pump for controlling the output pressure of the pump, said pump pressure control having a first position in which it connects said pressure sensing port to said low pressure passageway for establishing a low output pressure from the pump and a second position in which it connects said pressure sensing port to said hydraulic motor for establishing a higher output pressure from the pump.

In a drive system for a laundry flatwork ironer having a plurality of horizontal rollers and a steam chest below the rollers which is vertically adjustable toward and away from the rollers, the combination of:

• hydraulic cylinder-and-piston means for raising and lowering the steam chest;
• a pump for supplying pressurized fluid to said cylinder-and-piston means to operate the latter;
• valve means operable to connect the output of said pump to said cylinder-and-piston means to operate the latter at a predetermined fluid pressure for raising said steam chest and to reduce the fluid pressure in said cylinder-and-piston means after it has raised the steam chest;
• and a timer operatively coupled to said valve means to reduce the fluid pressure in said cylinder-and-piston means at a predetermined time after it has begun raising the steam chest.

In a drive system for a laundry flatowrk ironer having a plurality of horizontal rollers for ironing the flatwork and advancing it through the ironer and a steam chest below the rollers which is vertically adjustable toward and away from the rollers, the combination of:

• a hydraulic motor for driving the rollers;
• hydraulic cylinder-and-piston means for raising and lowering the steam chest;
• a pump for supplying pressurized fluid to both said motor and said cylinder-and-piston means;
• valve means operatively connected to control the flow of fluid from said pump to said motor;
• and valve means operatively connected to control the supply of pressurized fluid from said pump to said cylinder-and-piston means and comprising:
• a motor supply valve operatively connected to said motor to control the flow of fluid from said pump to said motor;
• and selectively operable control valve means operatively connected hydraulically to cause said motor supply valve either (a) to block fluid flow from said pump to said motor or (b) to establish fluid flow from said pump to said motor.