Apparatus and method for measuring rotational position

Claim 1

An apparatus for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being driven by a drive train (12) at a common rotational speed, including: means (90) driven in synchronism with said first element (70) for generating an electrical signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10), and an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element through a predetermined increment; means (10) operatively connected to said second rotating element (94) for generating an electric signal including one marker trigger pulse for each revolution of said second element (94) with respect to a fixed point of said machine (10) ; means (112) for receiving said reference pulses, said count pulses and said marker pulses, and for counting the number of said count pulses received subsequent to receipt of one of said trigger pulses and up to and simultaneous with receipt of the first succeeding one of the other of said trigger pulses; said pulse receiving and counting means (112) including a memory (120) for retaining therein said number of said counted clock pulses until receipt by said receiving and counting means (112) of the second succeeding one of said other trigger pulses; and means (106, 108) for selectively adjusting the circumferential setting of said second rotating element (94) with respect to said first rotating element (70); characterized by: means (124) for generating an electric signal including adjustment pulses, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) by said adjustment means (106, 108) through said increment of rotation corresponding to one of said count pulses; said pulse receiving and counting means (112) being adapted to receive said adjustment pulses, and to modify said number of said count pulses retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, received subsequent to receipt of said first other trigger pulse and up to and simultaneous with receipt of said second other trigger pulse.

Claim 2

An apparatus for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being driven by a drive train (12) at a common rotational speed, including: means (90) driven in synchronism with said first element (70) for generating an electrical signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10), and an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element through a predetermined increment; means (10) operatively connected to said second rotating element (94) for generating an electric signal including one marker trigger pulse for each revolution of said second element (94) with respect to a fixed point of said machine (10) ; means (112) for receiving said reference pulses, said count pulses and said marker pulses, and for counting the number of said count pulses received subsequent to receipt of one of said trigger pulses and up to and simultaneous with receipt of the first succeeding one of the other of said trigger pulses; said pulse receiving and counting means (112) including a memory (120) for retaining therein said number of said counted clock pulses until receipt by said receiving and counting means (112) of the second succeeding one of said other trigger pulses; and means (106, 108) for selectively adjusting the circumferential setting of said second rotating element (94) with respect to said first rotating element (70); characterized by: means (124) for generating an electric signal including adjustment pulses, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) by said adjustment means (106, 108) through said increment of rotation corresponding to one of said count pulses; said pulse receiving and counting means (112) being adapted to receive said adjustment pulses, and to modify said number of said count pulses retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, received subsequent to receipt of said first other trigger pulse and up to and simultaneous with receipt of said second other trigger pulse.

Claim 3

An apparatus for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being driven by a drive train (12) at a common rotational speed, including: means (90) driven in synchronism with said first element (70) for generating an electrical signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10), and an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element (70) through a predetermined increment; means (10) operatively connected to said second rotating element (94) for generating an electric signal including one marker trigger pulse for each revolution of said second element (94) with respect to a fixed point of said machine (10); means (112) for receiving said reference pulses, said count pulses and said marker pulses, and for counting the number of said count pulses received subsequent to receipt of one of said reference pulses and up to and simultaneous with receipt of the first succeeding one said marker pulses; said pulse receiving and counting means (112) including a memory (120) for retaining therein said number of said counted clock pulses until receipt by said receiving and counting means (112) of the second succeeding one of said marker pulses; and means (106, 108) for selectively adjusting the circumferential setting of said second rotating element (94) with respect to said first rotating element (70); characterized by: means (124)' for generating an electric signal including adjustment pulses, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) by said adjustment means (106, 108) through said increment of rotation corresponding to one of said count pulses; said pulse receiving and counting means (112) being adapted to receive said adjustment pulses, and to modify said number of said count pulses retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, received subsequent to receipt of said first marker pulse and up to and simultaneous with receipt of said second marker pulse.

Claim 4

An apparatus for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being driven by a drive train (12) at a common rotational speed, including: means (90) driven in synchronism with said first element (70) for generating an electrical signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10), and an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element (70) through a predetermined increment; means (10) operatively connected to said second rotating element (94) for generating an electric signal including one marker trigger pulse for each revolution of said second element (94) with respect to a fixed point of said machine (10); means (112) for receiving said reference pulses, said count pulses and said marker pulses, and for counting the number of said count pulses received subsequent to receipt of one of said reference pulses and up to and simultaneous with receipt of the first succeeding one said marker pulses; said pulse receiving and counting means (112) including a memory (120) for retaining therein said number of said counted clock pulses until receipt by said receiving and counting means (112) of the second succeeding one of said marker pulses; and means (106, 108) for selectively adjusting the circumferential setting of said second rotating element (94) with respect to said first rotating element (70); characterized by: means (124)' for generating an electric signal including adjustment pulses, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) by said adjustment means (106, 108) through said increment of rotation corresponding to one of said count pulses; said pulse receiving and counting means (112) being adapted to receive said adjustment pulses, and to modify said number of said count pulses retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, received subsequent to receipt of said first marker pulse and up to and simultaneous with receipt of said second marker pulse.

Claim 6

An apparatus as claimed in claims 1 or 2 wherein said means (90) for generating said reference pulse and said count pulses includes an incremental encoder.

Claim 7

An apparatus as claimed in claims 1 or 2 wherein said means (110) for generating said marker pulse includes two parts, a Hall effect switch and a metallic sensor to which said switch is responsive, one of said two parts being mounted so as to be rotatable in synchronism with said second rotatable element (94) and the other of said two parts being mounted so as to be stationary with respect to said second element (94), said parts cooperating once per revolution of said second element (94) for generation of said marker pulse.

Claim 8

An apparatus as claimed in claims 1 or 2 wherein said means (106, 108) for selective circumferential adjustment of said second element includes a differential device (106) having a first input from said drive train (12), an output drivingly connected to said second element (94), and a second input, said adjustment means (106, 108) further including a motor (108) connected to said second input for introducing rotational displacement between said drive train (12) and said second input.

Claim 10

An apparatus as claimed in claims 1 or 2 wherein said means (124) for generating said adjustment pulses includes means for generating a second electric signal for indicating the direction of adjustments made to the circumferential setting of said second rotating element (94), said pulse receiving and counting means (112) being further adapted to receive said second signal and for modifying said retained number of count pulses in a numerical direction corresponding to the rotational direction indicated by said second signal.

Claim 11

An apparatus as claimed in claims 1 or wherein said means for generating said adjustment pulses includes an incremental encoder (144), the shaft of said encoder (144) being rotated in response to adjustment of the circumferential setting of said second element (134).

Claim 14

A method for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being drivable by a drive train (12) at a common rotational speed, said machine (10) including means (106, 108) for selectively adjusting the circumferential setting of said second element (94) with respect to said first element (70), said method characterized by the steps of: generating an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element (70) through a predetermined increment; generating an electric signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10); generating an electric signal including one marker trigger pulse for each revolution said second element (94) with respect to a fixed point of said machine (10); generating an electric signal which, in the event said adjustment means (106, 108) is actuated, includes at least one adjustment pulse, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) through each said increment of rotation corresponding to one of said count pulses; counting said clock pulses generated subsequent to generation of one of said reference pulses and up to and simultaneous with generation of the first succeeding one of said marker pulses; retaining within a memory (120) the number of said counted clock pulses until genreation of the second succeeding one of said marker pulses; and modifying said number retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, generated subsequent to generation of said first marker pulse and up to and simultaneous with generation of said second marker pulse, said number of said clock pulses being modified substantially simultaneously with generation of said adjustment pulses.

Claim 15

A method for measuring with respect to a first rotating element (70) the circumferential setting of a second rotating element (94) of a machine (10) for operating on a moving web (24), said first and second elements (70, 94) being drivable by a drive train (12) at a common rotational speed, said machine (10) including means (106, 108) for selectively adjusting the circumferential setting of said second element (94) with respect to said first element (70), said method characterized by the steps of: generating an electric signal including a train of count pulses, one each of said count pulses being generated in response to rotation of said first element (70) through a predetermined increment; generating an electric signal including one reference trigger pulse for each revolution of said first element (70) with respect to a fixed point of said machine (10); generating an electric signal including one marker trigger pulse for each revolution said second element (94) with respect to a fixed point of said machine (10); generating an electric signal which, in the event said adjustment means (106, 108) is actuated, includes at least one adjustment pulse, a predetermined number of said adjustment pulses being generated in response to adjustment of said second element (94) through each said increment of rotation corresponding to one of said count pulses; counting said clock pulses generated subsequent to generation of one of said reference pulses and up to and simultaneous with generation of the first succeeding one of said marker pulses; retaining within a memory (120) the number of said counted clock pulses until genreation of the second succeeding one of said marker pulses; and modifying said number retained within said memory (120) by the number of said adjustment pulses, divided by said predetermined number, generated subsequent to generation of said first marker pulse and up to and simultaneous with generation of said second marker pulse, said number of said clock pulses being modified substantially simultaneously with generation of said adjustment pulses.