Material handling machine

Claim 2

A material handling machine comprising: a lift head having material pickup means thereon; a carrier means attached to said lift head, said carrier means being vertically shiftable upwardly and downwardly to raise and lower said lift head; bidirectional drive means in driving association with said carrier means, there being sufficient free play between said drive means and said carrier means that when said lift head engages a contact surface on its downward stroke and thereby removes stress normally exerted on said drive means by said carrier means, said drive means will be freely movable through a limited distance, said drive means being operable in a first direction to raise said carrier means and said lift head and in the opposite direction to lower said carrier means and said lift head; spring means engaging said drive means and maintained in a normally loaded condition by the stress normally exerted on said drive means by said carrier means; a control switch operable in one position to stop the movement of said drive means in said opposite direction to limit the downward movement of said carrier means and lift head; and a trip device for said control switch carried on said drive means, the unloading action of said spring when said pickup means engage a contact surface on the downward stroke of said lift head serving to move said drive means through said limited distance to thereby carry said trip device into a predetermined position wherein it actuates said switch to said one position wherein it stops the movement of said drive means in said opposite direction and terminates the downward movement of said carrier means and lift head.

Claim 3

A material handling machine as defined in claim 1 wherein: said bidirectional drive means comprises at least one chain guided around a sprocket with one fixed end secured in biasing, coacting relation with said spring means and having its opposite end attached to said carrier means, whereby the load of said carrier means and said lift head on said one end of said chain normally maintains said chain in tension against the biasing pressure of said spring means, and the tension on said chain is thus removed when said pickup means engages a contact surface on the downward stroke of said lift head, thereby producing slack in said chain and permitting said spring to move said fixed end of said chain and said trip device therewith through said limited distance to actuate said control switch.

Claim 4

A material handling machine as defined in claim 2 wherein: a power cylinder is attached to said chain sprocket and is operable to raise and lower said sprocket and said chain therewith, the flow of pressurizing fluid to said power cylinder in a direction to lower said sprocket, chain and carrier means being controlled by said control switch.

Claim 5

A material handling machine as defined in claim 1 wherein: said material pickup means comprises a plurality of vacuum cups connected to a vacuum source, said cups being adjustably mounted on said lift head for shifting movement longitudinally and transversely of said lift head, whereby said vacuum cups may be adjusted on said lift head to pick up varying numbers of pieces of different sizes.

Claim 6

A material handling machine as defined in claim 1, and further including a receiving bed on which material is received and accumulated to be picked up by said machine; displaceable material stop means at a predetermined location on said receiving bed for stopping pieces of material conveyed onto and along said bed at a predetermined point thereon; and a control switch mounted adjacent to said stop means and operable in response to the displacement of said stop means to actuate said drive means for movement in said opposite direction to lower said lift head.

Claim 7

Material handling apparatus comprising: a horizontally shiftable carriage on an elevated, horizontal guide track; reversible motor means drivingly associated with said carriage and operable to move said carriage back and forth on said track; a lift head mounted on said carriage for vertical movement upwardly and downwardly, said lift head being horizontally shiftable with said carriage; material pickup means on said lift head; means for raising said lift head; a motor means control device operative to initiate movement of said motor means in one direction to shift said carriage in a predetermined, horizontal direction on said track; a supply station at which pieces of material to be picked up by said material handling machine are deposited; a stacking station at which material picked up from said supply station by said machine is stacked; a signal emitter positioned to send a signal along a horizontal path which intersects the vertical direction of extent of a stack of material accumulating at said stacking station and on which said material handling machine is placing pieces of material picked up from said supply station; a signal sensing device mounted on said lift head and operative in response to a signal received from said signal emitter to deactivate said lift head raising means and to actUate said motor means control device to initiate movement of said carriage in said predetermined direction, whereby, with said lift head moving upwardly with a piece of material picked up from said supply station, the stack of material accumulating at said stacking station will interfere with the transmission and reception of said signal by said emitter and sensing device and said sensing device will not deactivate said lift head raising means and actuate said motor means control device until said lift head and said sensing device thereon have been elevated to a level above the top of the stack of material accumulating at said stacking station.

Claim 8

Material handling apparatus comprising: a horizontally shiftable carriage on an elevated, horizontal guide track; reversible motor means drivingly associated with said carriage and operable to move said carriage back and forth on said track; a lift head mounted on said carriage for vertical movement upwardly and downwardly, said lift head being horizontally shiftable with said carriage; material pickup means on said lift head; means for raising said lift head; a motor means control device operative to initiate movement of said motor means in one direction to shift said carriage in a predetermined, horizontal direction on said track; a supply station at which pieces of material to be picked up by said material handling machine are deposited; a stacking station at which material picked up from said supply station by said machine is stacked; a signal emitter positioned to send a signal along a horizontal path which intersects the vertical direction of extent of a stack of material accumulating at said stacking station and on which said material handling machine is placing pieces of material picked up from said supply station; a signal sensing device mounted on said lift head and operative in response to a signal received from said signal emitter to deactivate said lift head raising means and to actUate said motor means control device to initiate movement of said carriage in said predetermined direction, whereby, with said lift head moving upwardly with a piece of material picked up from said supply station, the stack of material accumulating at said stacking station will interfere with the transmission and reception of said signal by said emitter and sensing device and said sensing device will not deactivate said lift head raising means and actuate said motor means control device until said lift head and said sensing device thereon have been elevated to a level above the top of the stack of material accumulating at said stacking station.

Claim 9

Material handling apparatus as defined in claim 6 wherein: said motor means control device is electrically operable; said signal emitter is a light source; and said sensing device is a photoelectric cell operative to open and close a circuit to said control device.

Claim 10

Material handling apparatus as defined in claim 7 wherein: a height control limit switch is interposed in said circuit with said photoelectric cell and said motor means control device and is operative in response to the elevation of said lift head to a predetermined minimum clearance height to close a set of contacts in said circuit to said motor control device.

Claim 11

Material handling apparatus as defined in claim 6 wherein: said apparatus includes means for lowering said head; said stacking station is comprised of first and second material receiving stations; and first and second limit switches spaced apart along the length of said track in substantially vertical alignment with said first and second material receiving stations respectively, each of said limit switches being operative in a control circuit in response to contact by said carriage to actuate said lift head lowering means, said limit switches being connected in a logic circuit of said control circuit in such a manner that only one of said switches is in said control circuit at a time, whereby said limit switches alternately actuate said lift head lowering means in response to contact by said carriage to cause the alternate lowering of said lift head at first one and then the other of said material receiving stations to stack pieces of material at said stations.

Claim 12

Material handling apparatus comprising: a material handling machine having a lift head movable upwardly and downwardly; material pickup means on said lift head; means for lowering said lift head to pick up material; a receiving bed on which material is received and accumulated; material stop means at a predetermined location on said receiving bed for stopping pieces of material conveyed onto and along said bed at a predetermined point thereon; a control device positioned at a location adjacent to said receiving bed which is a predetermined distance forwardly of said stop means in the direction from which material is received, such that the distance between said stop means and said control device is substantially equal to a predetermined total length of material to be accumulated on said bed, said control device including a time delay relay and being operative in response to the presence of material on said bed at said location for a predetermined period of time to actuate said means for lowering said lift head to pick up the material accumulated on said bed, said time delay relay being set to permit short lengths of material to move past said control device location onto said bed towards said stop means without activating said control device, whereby said control device will not actuate said means for lowering said lift head until a plurality of pieces of material or a single piece of material having a length equal to said predetermined total length have accumulated on said receiving bed.

Claim 13

Material handling apparatus comprising: a material handling machine having a lift head movable upwardly and downwardly; material pickup means on said lift head; means for lowering said lift head to pick up material; a receiving bed on which material is received and accumulated; material stop means at a predetermined location on said receiving bed for stopping pieces of material conveyed onto and along said bed at a predetermined point thereon; a control device positioned at a location adjacent to said receiving bed which is a predetermined distance forwardly of said stop means in the direction from which material is received, such that the distance between said stop means and said control device is substantially equal to a predetermined total length of material to be accumulated on said bed, said control device including a time delay relay and being operative in response to the presence of material on said bed at said location for a predetermined period of time to actuate said means for lowering said lift head to pick up the material accumulated on said bed, said time delay relay being set to permit short lengths of material to move past said control device location onto said bed towards said stop means without activating said control device, whereby said control device will not actuate said means for lowering said lift head until a plurality of pieces of material or a single piece of material having a length equal to said predetermined total length have accumulated on said receiving bed.

Claim 14

Material handling apparatus as defined in claim 10 wherein: said control device is a light-sensitive photoelectric cell controller having at least a portion thereof so positIoned under said receiving bed at said location that the presence of material on said bed at said location will block the transmission of light to said controller and thereby initiate the lift head control function of said photoelectric cell controller.

Claim 15

Material handling apparatus as defined in claim 10 wherein: said material stop means is longitudinally adjustable on said receiving bed towards and away from said control device to permit adjusting the distance therebetween for the particular length of material desired to be accumulated on said receiving bed.

Claim 16

Material handling apparatus as defined in claim 10 wherein: said pickup means on said lift head comprises a plurality of material holding devices adjustably mounted on said lift head for movement longitudinally thereof in a direction extending lengthwise of said receiving bed, whereby said pickup means may be spaced and positioned on said lift head to pick up different sizes and accumulated lengths of material from said receiving bed.

Claim 17

Material handling apparatus as defined in claim 10 wherein: said means for lowering said lift head comprises vertically shiftable carrier means attached to said lift head and bidirectional drive means drivingly associated therewith, there being sufficient free play between said drive means and said carrier means that when said pickup means engages material on said receiving bed on the downward stroke of said lift head to thereby remove stress normally exerted on said drive means by said carrier means, said drive means will be freely movable through a limited distance; spring means engaging said drive means and maintained in a normally loaded condition by the stress normally exerted on said drive means by said carrier means; a control switch operable in one position to stop the movement of said drive means in a direction lowering said carrier means and lift head, said switch having an actuator disposed in proximity to said drive means; and a trip device for said switch actuator carried on said drive means, the unloading action of said spring when said pickup means strikes material on said receiving bed serving to move said drive means through said limited distance to thereby carry said trip device into engagement with said switch actuator and move said switch to said one position wherein it stops the movement of said drive means in said lift head lowering direction.

Claim 18

A material handling machine comprising: a horizontally shiftable carriage on an elevated horizontal guide track; reversible motor means drivingly associated with said carriage and operable to move said carriage back and forth on said track; a motor means control device operable to initiate movement of said motor means in one direction to shift said carriage in a predetermined, horizontal direction on said track; a lift head mounted on said carriage for vertical movement upwardly and downwardly, and horizontally shiftable with said carriage; material pickup means on said lift head; means for lowering said lift head; a work station at a first location along said guide track; first and second material handling stations adjacent to each other at a location along said guide track between said work station and one end of said guide track at which the same material stacking or picking-up functions are carried out in proximity to said machine; first and second limit switches spaced closely together along the length of said track in substantially vertical alignment with said first and second material handling stations respectively, each of said limit switches being operative in a control circuit to actuate said lift head lowering means in response to contact by said carriage as it moves in the same predetermined direction towards said first and second material handling stations, said limit switches being connected in a logic circuit of said control circuit in such a manner that only one of said switches is in said control circuit At a time, whereby said limit switches selectively and intermittently actuate said lift head lowering means in response to contact by said carriage as it moves in said predetermined direction to cause the selective and intermittent lowering of said lift head at said material handling stations to carry out the same material handling function at each of said stations.

Claim 19

A material handling machine comprising: a horizontally shiftable carriage on an elevated horizontal guide track; reversible motor means drivingly associated with said carriage and operable to move said carriage back and forth on said track; a motor means control device operable to initiate movement of said motor means in one direction to shift said carriage in a predetermined, horizontal direction on said track; a lift head mounted on said carriage for vertical movement upwardly and downwardly, and horizontally shiftable with said carriage; material pickup means on said lift head; means for lowering said lift head; a work station at a first location along said guide track; first and second material handling stations adjacent to each other at a location along said guide track between said work station and one end of said guide track at which the same material stacking or picking-up functions are carried out in proximity to said machine; first and second limit switches spaced closely together along the length of said track in substantially vertical alignment with said first and second material handling stations respectively, each of said limit switches being operative in a control circuit to actuate said lift head lowering means in response to contact by said carriage as it moves in the same predetermined direction towards said first and second material handling stations, said limit switches being connected in a logic circuit of said control circuit in such a manner that only one of said switches is in said control circuit At a time, whereby said limit switches selectively and intermittently actuate said lift head lowering means in response to contact by said carriage as it moves in said predetermined direction to cause the selective and intermittent lowering of said lift head at said material handling stations to carry out the same material handling function at each of said stations.

Claim 20

A material handling machine as defined in claim 1 wherein: said control switch has an actuator disposed in proximity to said drive means, and said trip device is carried into engagement with said switch actuator and thereby moves said switch to said one position as said drive means moves through said limited distance.