Superposed sheet detection

Claim 2

Apparatus for determining the thickness of material, comprising: means for varying the impedance of variable impedance means in accordance with the thickness of said material; detecting means connected to said variable impedance means for detecting variations of impedance and for generating signals representative of said variations; means for comparing an initial one of said generated signals with each of subsequent ones of said generated signals and for indicating the results of said comparison; means for coupling said means for comparing to said detecting means; and means for resetting said means for comparing to a quiescent conditon.

Claim 3

The apparatus of claim 1 wherein said means for varying the impedance of variable impedance means comprises a rotatable member disposed adjacent reference means to define a spaced relationship between said rotatable member and said reference means, said rotatable member being adapted to rotate in response to the positioning of material in said spaced relationship such that the angular displacement of said rotatable member is determined by the thickness of said material.

Claim 4

The apparaTus of claim 2 wherein said variable impedance means comprises variable resistance means operably coupled to said rotatable member whereby the resistance of said variable resistance means is varied in accordance with the angular displacement of said rotatable member.

Claim 5

The apparatus of claim 3 wherein said variable resistance means comprises a strain gage mechanically coupled to said rotatable member.

Claim 6

The apparatus of claim 3 wherein said variable resistance means comprises: a surface of photoresistive material having a resistance dependent upon the position of light impinging thereon; and a light emissive element optically coupled to said surface of photoresistive material and mechanically coupled to said rotatable member such that the position of light transmitted to said surface of photoresistive material from said light emissive element is adapted to vary in accordance with the angular displacement of said rotatable member.

Claim 7

The apparatus of claim 1 wherein said detecting means comprises impedance bridge means including said variable impedance means in an arm thereof.

Claim 8

The apparatus of claim 1 wherein said means for comparing comprises: storage means adapted to store said initial one of said generated signals; and difference means having a first input coupled to said storage means and a second input, said difference means adapted to produce an output signal proportional to the difference between the signals supplied to the inputs thereof.

Claim 9

The apparatus of claim 7 wherein said means for coupling comprises: switch means admitting of a first state whereby said storage means is supplied with an initial one of said generated signals and a second state whereby said second input of said difference means is supplied with subsequent ones of said generated signals; and switch control means coupled to said switch means for controlling the state of said switch means.

Claim 10

The apparatus of claim 8 wherein said means for resetting said means for comparing to a quiescent condition comprises: means for erasing the contents of said storage means; and activating means coupled to said difference means for activating said means for erasing when said output signal exceeds a predetermined threshold, said activating means being adapted to activate further means.

Claim 11

The apparatus of claim 9 wherein said means for comparing includes interrupt means adapted to interrupt the operation of said difference means for desired intervals.

Claim 12

Self-adjusting apparatus for detecting a multiple of sheets of material conveyed by a sheet transport device, comprising: sensing means disposed at a predetermined location in said sheet transport device for sensing the passage sheets of material; means for producing modifications of the impedance of variable impedance means in accordance with the thickness of said sheets of material; detecting means controlled by said sensing means for detecting differences between an initial modification of said variable impedance means and subsequent modifications of said variable impedance means; and further means coupled to said detecting means for producing an output signal in response to detected differences that exceed a predetermined threshold.

Claim 13

Self-adjusting apparatus for detecting a multiple of sheets of material conveyed by a sheet transport device, comprising: sensing means disposed at a predetermined location in said sheet transport device for sensing the passage sheets of material; means for producing modifications of the impedance of variable impedance means in accordance with the thickness of said sheets of material; detecting means controlled by said sensing means for detecting differences between an initial modification of said variable impedance means and subsequent modifications of said variable impedance means; and further means coupled to said detecting means for producing an output signal in response to detected differences that exceed a predetermined threshold.

Claim 14

The apparatus of claim 11 wherein said detecting means comprises: signal generating means for generating signals that are a function of the impedance of said variable impedance means; storage means for storing an initial one of said generated signals; comparison means coupled to said storage means for comparing the signal stored by said storage means with subsequent signals generated by said signal generating means; and means controlled by said sensing means for selectively coupling said signal generating means to said storage means and said comparison means.

Claim 15

The apparatus of claim 12 wherein said means for producing modifications of the impedance of variable impedance means comprises a rotatable member operAbly coupled to said variable impedance means and disposed adjacent reference means to define a spaced relationship between said rotatable member and said reference means, said rotatable member being adapted to rotate in response to the transport of sheets of material through said spaced relationship such that the angular displacement of said rotatable member is determined by the thickness of said sheets of material.

Claim 16

The apparatus of claim 13 wherein said variable impedance means comprises a strain gage mechanically coupled to said rotatable member whereby the resistance of said strain gage is determined by the angular displacement of said rotatable member.

Claim 17

The apparatus of claim 13 wherein said variable impedance means comprises: photoresistive material having a resistance dependent upon the relative position of radiant energy impinging on the surface thereof; and a source of radiant energy mechanically coupled to said rotatable member such that the relative position of radiant energy transmitted to said surface of photoresistive material, by said source of radiant energy is adapted to vary in accordance with the angular displacement of said rotatable member.

Claim 18

The apparatus of claim 13 wherein said further means comprises: deflecting means adapted to be interposed in the path of said sheets of material conveyed by said sheet transport device for deflecting the sheets of material away from said sheet transport device; and actuating means coupled to said comparison means for actuating said deflecting means when the difference between the signals compared by said comparison means exceeds a predetermined threshold.

Claim 19

The apparatus of claim 16 further including reset means adapted to be actuated by said actuating means for erasing the contents of said storage means.

Claim 20

The apparatus of claim 17 wherein said means for selectively coupling comprises switch means responsive to said sensing means to couple said storage means to said signal generating means when an initial sheet of material is conveyed by said sheet transport device and to couple said comparison means to said signal generating means when subsequent sheets of material are conveyed by said sheet transport device.

Claim 21

The apparatus of claim 18 further including interrupt means responsive to said sensing means for interrupting the operation of said comparison means for determined intervals of time.

Claim 22

The apparatus of claim 13 wherein said signal generating means comprises: impedance bridge means including said variable impedance means in an arm thereof; and means for applying energy to said impedance bridge means.

Claim 23

The apparatus of claim 20 wherein said storage means comprises capacitance means adapted to store a signal generated by said impedance bridge means.

Claim 24

The apparatus of claim 21 wherein said comparison means comprises differential amplifier means including a first input terminal adapted to be supplied with the signal stored by said capacitance means and a second input terminal adapted to be supplied with a signal generated by said impedance bridge means.

Claim 25

The apparatus of claim 22 wherein said means for selectively coupling comprises: switch means admitting of a first state whereby said capacitance means is supplied with a signal generated by said impedance bridge means and a second state whereby said differential amplifier means is enabled to compare said stored signal with a signal generated by said impedance bridge means; and switch control means coupled to said switch means and responsive to said sensing means for controlling the state of said switch means.

Claim 26

Superposed sheet detecting apparatus for use in a sheet feeding mechanism wherein the thickness of the sheets may be selectively variable, comprising: sensing means disposed at a predetermined location in said sheet feeding mechanism for sensing the transporting of sheets past said predetermined location and for initiating a detecting cycle; a rOtatable member positioned in cooperative relationship with respect to reference means and adapted to receive sheets transported thereto, said rotatable member being adapted for angular displacement in accordance with the thickness of said sheets; signal generating means operably coupled to said rotatable member for generating signals representative of the thickness of said sheets; reference signal means coupled to said signal generating means for providing a reference signal representative of the thickness of an initial sheet sensed by said sensing means; comparison means coupled to said reference signal means and said signal generating means for comparing said reference signal to generated signals; actuating means coupled to said comparison means and adapted to be energized when the difference between the thickness of an initial sheet and the thickness of a subsequent sheet exceeds a predetermined amount; and means responsive to said actuating means for terminating said detecting cycle.

Claim 27

Superposed sheet detecting apparatus for use in a sheet feeding mechanism wherein the thickness of the sheets may be selectively variable, comprising: sensing means disposed at a predetermined location in said sheet feeding mechanism for sensing the transporting of sheets past said predetermined location and for initiating a detecting cycle; a rOtatable member positioned in cooperative relationship with respect to reference means and adapted to receive sheets transported thereto, said rotatable member being adapted for angular displacement in accordance with the thickness of said sheets; signal generating means operably coupled to said rotatable member for generating signals representative of the thickness of said sheets; reference signal means coupled to said signal generating means for providing a reference signal representative of the thickness of an initial sheet sensed by said sensing means; comparison means coupled to said reference signal means and said signal generating means for comparing said reference signal to generated signals; actuating means coupled to said comparison means and adapted to be energized when the difference between the thickness of an initial sheet and the thickness of a subsequent sheet exceeds a predetermined amount; and means responsive to said actuating means for terminating said detecting cycle.

Claim 28

Superposed sheet detecting apparatus for use in a sheet feeding mechanism wherein the thickness of the sheets may be selectively variable, comprising: means for receiving sheets transported thereto and for producing signals representative of the thickness of said sheets; storage means selectively coupled to said means for producing signals for storing signals representative of the thickness of an initially transported sheet; comparison means coupled to said storage means and said means for producing signals for comparing said stored signals to said produced signals; and means coupled to said comparison means for providing an output signal to indicate when the difference between the thickness of an initial sheet and the thickness of a subsequently transported sheet exceeds a predetermined amount.

Claim 29

Superposed sheet detecting apparatus for use in a sheet feeding mechanism wherein the thickness of the sheets may be selectively variable, comprising: means for receiving sheets transported thereto and for producing signals representative of the thickness of said sheets; storage means selectively coupled to said means for producing signals for storing signals representative of the thickness of an initially transported sheet; comparison means coupled to said storage means and said means for producing signals for comparing said stored signals to said produced signals; and means coupled to said comparison means for providing an output signal to indicate when the difference between the thickness of an initial sheet and the thickness of a subsequently transported sheet exceeds a predetermined amount.