Bi-directionally movable platform control

Claim 2

In combination with a bi-directionally movable platform for supporting a stack of sheets of material adapted to be fed to an operating device, control means for controlling the operation of platform driving means, comprising: direction determining means comprising flip-flop means for producing a first signal to drive said platform in a first direction and a second signal to drive said platform in a second direction whereby said first and second signals are produced when said flip-flop means assumes first and second states, respectively; first sensing means for sensing when said platform assumes a first extreme position; first means coupled to said first sensing means and responsive to the energization of a selecting switch for actuating said direction determining means to produce said first signal when said platform is not in said first extreme position; second means selectively responsive to the de-energization of said selecting switch and to the operating condition of said operating device for actuating said direction determining means to produce said second signal; and drive control means coupled to said direction determining means and responsive to said first and second signals to drive said platform driving means in a first and second direction, respectively.

Claim 3

The combination of claim 1 wherein said first mEans comprises coincidence means having a first input coupled to said selecting switch, a second input coupled to said first sensing means and an output coupled to said flip-flop means for driving said flip-flop means into its first state when said selecting switch is energized and said platform is not in its first extreme position.

Claim 4

The combination of claim 2 wherein said second means comprises: OR circuit means having a first input coupled to said first sensing means, a second input adapted to be supplied with signals representing the operating condition of said operating device and an output coupled to said flip-flop means for driving said flip-flop means into its second state when said platform is not in its first extreme position or said operating device admits of predetermined operating conditions; and means for preventing said flip-flop means from being driven into its second state when said coincidence means is energized.

Claim 5

The combination of claim 2 wherein said means for coupling comprises further coincidence means having a first input coupled to said second sensing means, a second input coupled to said flip-flop means and an output coupled to said drive control means.

Claim 6

In an electrostatic reproduction machine wherein a viewable image is formed on sheets of material supplied by an elevator assembly upon which said sheets are stacked, apparatus for regulating the position of said elevator assembly in response to operator-performed functions, comprising: direction determining means for producing a first signal to drive said elevator assembly in a downward direction and a second signal to drive said elevator assembly in an upward direction; first sensing means for sensing when said elevator assembly assumes an extreme downward position; first means comprising AND gate means having a first input coupled to an ''''elevator down'''' switch and a second input coupled to said first sensing means for producing said first signal when said ''''elevator down'''' switch is operated and said elevator assembly is not in said extreme downward position; second means selectively responsive to the release of said ''''elevator down'''' switch and to signals representing predetermined operating conditions of said electrostatic reproduction machine for actuating said direction determining means to produce said second signal; and elevator drive means coupled to said direction determining means and responsive to said first and second signals for driving said elevator assembly in a downward and an upward direction, respectively.

Claim 7

In an electrostatic reproduction machine wherein a viewable image is formed on sheets of material supplied by an elevator assembly upon which said sheets are stacked, apparatus for regulating the position of said elevator assembly in response to operator-performed functions, comprising: direction determining means for producing a first signal to drive said elevator assembly in a downward direction and a second signal to drive said elevator assembly in an upward direction; first sensing means for sensing when said elevator assembly assumes an extreme downward position; first means comprising AND gate means having a first input coupled to an ''''elevator down'''' switch and a second input coupled to said first sensing means for producing said first signal when said ''''elevator down'''' switch is operated and said elevator assembly is not in said extreme downward position; second means selectively responsive to the release of said ''''elevator down'''' switch and to signals representing predetermined operating conditions of said electrostatic reproduction machine for actuating said direction determining means to produce said second signal; and elevator drive means coupled to said direction determining means and responsive to said first and second signals for driving said elevator assembly in a downward and an upward direction, respectively.

Claim 8

The apparatus of claim 5 wherein said second means comprises OR circuit means having a first input coupled to said first sensing means, a second input adapted to be supplied with a signal generated at a predetermined time subsequent to the completion of an operating cycle by said electrostatic reproduction machine, a third input coupled to an operating cycle initiation switch and a fourth input adapted to be supplied with a signal generated in response to a predetermined operator-initiated action for producing a second actuating signal.

Claim 9

The apparatus of claim 6 wherein said direction determining means comprises flip-flop means having a first input coupled to said AND gate means and responsive to said first actuating signal to assume a first state and a second input coupled to said OR circuit means and responsive to said second actuating signal to assume a second state, said flip-flop means being inhibited from assuming said second state when said first actuating signal is applied to said first input.

Claim 10

The apparatus of claim 7 further including: second sensing means for sensing when said elevator assembly is in a proper position for supplying said sheets of material stacked thereon; and further AND gate means having a first input coupled to said flip-flop means and a second input coupled to said second sensing means for supplying said elevator drive means with an eneRgizing signal to drive said elevator assembly in an upward direction when said flip-flop means assumes its second state and said elevator assembly is not in said proper position.

Claim 11

The apparatus of claim 8 wherein said fourth input of said OR circuit means is coupled to switch means adapted to be closed when an access door of said elevator assembly is closed, said access door providing access by an operator to said elevator assembly to effect the loading and unloading of said elevator assembly with sheets of material.

Claim 12

In an electrostatic reproduction machine wherein an image is formed on sheets of material supplied from an elevator assembly upon which said sheets are stacked, apparatus for regulating the position of the elevator assembly in response to machine and operator-performed functions, comprising: elevator drive means for driving said elevator assembly between an extreme upper position and an extreme lower position; sheet sensing means responsive to the position of the top sheet on the elevator assembly for energizing said elevator drive means to move said elevator assembly in an upward direction as the sheet supply is depleted during a machine operating cycle to maintain the top sheet in a position to be fed through the reproduction machine; an ''''elevator down'''' switch adapted for operation by the machine operator for overriding said sheet sensing means to energize said elevator drive means to move said elevator assembly in a downward direction; and control means adapted to prevent energization of said elevator drive means by said ''''elevator down'''' switch during a machine operating cycle.

Claim 13

In an electrostatic reproduction machine wherein an image is formed on sheets of material supplied from an elevator assembly upon which said sheets are stacked, apparatus for regulating the position of the elevator assembly in response to machine and operator-performed functions, comprising: elevator drive means for driving said elevator assembly between an extreme upper position and an extreme lower position; sheet sensing means responsive to the position of the top sheet on the elevator assembly for energizing said elevator drive means to move said elevator assembly in an upward direction as the sheet supply is depleted during a machine operating cycle to maintain the top sheet in a position to be fed through the reproduction machine; an ''''elevator down'''' switch adapted for operation by the machine operator for overriding said sheet sensing means to energize said elevator drive means to move said elevator assembly in a downward direction; and control means adapted to prevent energization of said elevator drive means by said ''''elevator down'''' switch during a machine operating cycle.

Claim 14

Apparatus for regulating the position of the elevator assembly in an electrostatic reproduction machine according to claim 10 further including elevator sensing means for sensing when said elevator assembly assumes an extreme downward position in response to operation of the ''''elevator down'''' switch; and time delay means responsive to said elevator sensing means to maintain said elevator assembly in the extreme downward position after the ''''elevator down'''' switch is released to prevent immediate upward movement thereof in response to the absence of sheets of said sheet sensing means.

Claim 15

Apparatus for regulating the position of the elevator assembly in an electrostatic reproduction machine according to claim 11 further including means for overriding said time delay means upon the start of a machine operating cycle to allow said elevator assembly to assume the required position for feeding sheets through the reproduction machine.

Claim 16

Apparatus for regulating the position of the elevator assembly in an electrostatic reproduction machine according to claim 12 wherein the electrostatic reproduction machine includes an elevator assembly cover for enclosing the elevator assembly, said apparatus further including cover interlock means associated with said cover to de-energize said elevator assembly when said cover is opened, said means for overriding said time delay means further including means associated with said cover interlock means for overriding said time delay means when said cover is opened and subsequently closed.