Cutting device control

Claim 2

In apparatus for severing work, a cutting device, a first motor for effecting cutting operation of said cutting device, and a second motor for moving said operating cutting device to and through said work and for returning it to a non-cutting position, the improvement comprising means for monitoring the power required by said first motor during work cutting and non-cutting operations, including electrical switch contacts affected by said monitoring means and included in an electrical circuit which controls operation of said second motor, said switch contacts being set in one position by said monitoring means when said first motor requires a greater amount of power for the cutting operation, and said switch contacts being moved to another position by said monitoring means when said first motor requires a decreased amount of power upon completiong of the cutting action, said switch contacts in said other position affecting said control circuit to cause actuation of said second motor means to return said cutting device to non-cutting position removed from the work.

Claim 3

In apparatus for severing work, comprising a rotatable cutter, an electric motor for rotating said cutter, a further motor for moving said cutter to and through the work and for returning it to non cutting position, the improvement comprising a current relay for monitoring the current flow from an electrical power source to said electric motor, electrical switch contacts affected by said current relay and included in an electrical circuit which controls operation of said further motor, said switch contacts being set in one position by said current relay when said electric motor requires a greater amount of power for the cutting operation of said disc, and said switch contacts being moved to another position by said current relay when current flow to said electric motor decreases upon completion of the cutting operation of said disc, said switch contacts in said other position affeCting said electrical circuit to cause actuation of said further motor to return said cutting disc to a non-cutting position removed from the work.

Claim 4

In apparatus for severing work, comprising a rotatable cutter, an electric motor for rotating said cutter, a further motor for moving said cutter to and through the work and for returning it to non cutting position, the improvement comprising a current relay for monitoring the current flow from an electrical power source to said electric motor, electrical switch contacts affected by said current relay and included in an electrical circuit which controls operation of said further motor, said switch contacts being set in one position by said current relay when said electric motor requires a greater amount of power for the cutting operation of said disc, and said switch contacts being moved to another position by said current relay when current flow to said electric motor decreases upon completion of the cutting operation of said disc, said switch contacts in said other position affeCting said electrical circuit to cause actuation of said further motor to return said cutting disc to a non-cutting position removed from the work.

Claim 5

The construction according to claim 2 wherein said current relay is a control meter relay which is connected across the secondary of a transformer, the transformer primary being connected in series in a power line leading to the electric motor.

Claim 6

The construction according to claim 3 wherein said control meter relay comprises a rotatably mounted meter coil which rotates an amount proportional to the current demand of said electric motor, a photo conductive cell for operating said switch contacts, an electric light whose rays affect operation of said cell, and a shield carried by said meter coil for blocking rays to said cell when said electric motor requires a greater amount of current.

Claim 7

In apparatus for severing work, comprising a rotatable cutter, an electric motor for rotating said cutter, a fluid cylinder for moving said cutter to and through the work and for returning it to a non cutting position clear of the work, and a fluid valve for controlling flow of pressure fluid to opposite ends of said fluid cylinder, the plunger of said valve being movable to one position by a first solenoid to actuate the piston in said cylinder in a direction to cause it to move said cutter to and through the work, and said plunger being movable to another position by a second solenoid to actuate the piston in said cylinder in an opposite direction to cause it to move said cutter to a non-cutting position removed from the work, the improvement comprising a current relay for monitoring the current flow from an electrical power source to said electric motor, electrical switch contacts affected by said current relay and included in an electrical control circuit with said first and second solenoids, said switch contacts being held in closed position by said current relay when said electric motor draws a relatively light amount of current during non-cutting rotation to cause energization of said second solenoid and hold or move said cutter to non cutting position, a manually operable switch in said control circuit closed momentarily to energize said first solenoid and simultaneously cause opening of said switch contacts to deenergize said second solenoid, whereby said cutter is movable to and through the work, and said switch contacts being again closed by said current relay when said cutter has completed the cut and again draws a relatively light amount of current to again energize said second solenoid to shift said valve plunger to cause said cylinder to return said cutter disc to non cutting position.

Claim 8

In apparatus for severing work, comprising a rotatable cutter, an electric motor for rotating said cutter, a fluid cylinder for moving said cutter to and through the work and for returning it to a non cutting position clear of the work, and a fluid valve for controlling flow of pressure fluid to opposite ends of said fluid cylinder, the plunger of said valve being movable to one position by a first solenoid to actuate the piston in said cylinder in a direction to cause it to move said cutter to and through the work, and said plunger being movable to another position by a second solenoid to actuate the piston in said cylinder in an opposite direction to cause it to move said cutter to a non-cutting position removed from the work, the improvement comprising a current relay for monitoring the current flow from an electrical power source to said electric motor, electrical switch contacts affected by said current relay and included in an electrical control circuit with said first and second solenoids, said switch contacts being held in closed position by said current relay when said electric motor draws a relatively light amount of current during non-cutting rotation to cause energization of said second solenoid and hold or move said cutter to non cutting position, a manually operable switch in said control circuit closed momentarily to energize said first solenoid and simultaneously cause opening of said switch contacts to deenergize said second solenoid, whereby said cutter is movable to and through the work, and said switch contacts being again closed by said current relay when said cutter has completed the cut and again draws a relatively light amount of current to again energize said second solenoid to shift said valve plunger to cause said cylinder to return said cutter disc to non cutting position.

Claim 9

The construction according to claim 5 and further including a time delay for holding said cutter in the cut of said work to smooth edges of the cut following said cutting operation and prior to return of said cutter to non-cutting position.

Claim 10

The construction of claim 5 wherein said current relay is a control meter relay which is connected across the secondary of transformer, the transformer primary being connected in series in a power line leading to the electric motor.

Claim 11

The construction of claim 5 wherein the current relay is an instantaneous trip current relay with the coil of the latter disposed in series in a power line leading to the electric motor.