Differential drive for tension rollers

Claim 2

A tension roll assembly for a sheet metal working line and comprising: first and second tension rolls about and between which a sheet metal strip runs; a motive power source; a first roll drive transmission operatively extending between said motive power source and said first tension roll to cause rotation of said first tension roll on operatIon of said motive power source; a second roll drive transmission operatively extending between said motive power source and said second tension roll to cause rotation of said second tension roll on operation of said motive power source; a first differential including a main drive input, a main drive output and a control drive input, said first differential being operatively coupled in said second roll drive transmission to transmit drive motion from said motive power source to said second tension roll at a variable speed depending on the magnitude of the control drive to said first differential; a first variable speed control motor operatively coupled to said control drive input of said first differential; a first sensor coupled to said first tension roll and operative to provide an output signal indicative of the magnitude of a first roll parameter selected from the rotational speed and the shaft torque of said first tension roll, said first sensor also being operatively coupled to said variable speed control motor to cause variation in the speed of said control motor in response to variation in the magnitude of said first roll parameter, thereby automatically to adjust the speed of the main drive output of said first differential and consequently the speed of said second tension roll driven thereby automatically in response to variation of the magnitude of said first roll parameter; a third tension roll about which the sheet metal strip runs; a third roll drive transmission operatively extending between said motive power source and said third tension roll to cause rotation of said third tension roll on operation of said motive power source; a second differential including a main drive input, a main drive output and a control drive input, said second differential being operatively coupled in said third roll drive transmission to transmit drive motion from said motive power source to said third tension roll at a variable speed depending on the magnitude of the control drive to said second differential; a second variable speed control motor operatively coupled to said control drive input of said second differential; and a second sensor coupled to said second tension roll and operative to provide an output signal indicative of the magnitude of a second roll parameter selected from the rotational speed and the shaft torque of said second tension roll, said second sensor also being operatively coupled to said second variable speed control motor to cause variation in the speed of said second control motor in response to variation in the magnitude of said second roll parameter thereby automatically to adjust the speed of the main drive output of said second differential and consequently the speed of said third tension roll driven thereby automatically in response to variation in the magnitude of said second roll parameter.

Claim 3

A tension roll assembly as claimed in claim 1 in which said first sensor is a tachometer operatively coupled to said first tension roll to provide an output signal indicative of the magnitude of the rotational speed of said first tension roll.

Claim 4

A tension roll assembly as claimed in claim 1 and which additionally comprises: a fourth tension roll about which the sheet metal strip runs; a fourth roll drive transmission operatively extending between said motive power source and said fourth tension roll to cause rotation of said fourth tension roll on operation of said motive power source; a third differential including a main drive input, a main drive output and a control drive input, said third differential being operatively coupled in said fourth roll drive transmission to transmit drive motion from said motive power source to said fourth tension roll at a variable speed depending on the magnitude of the control drive to said third differential; a third variable speed control motor operatively coupled to said control drive input of said third differential; and a third sensor coupled to said third tension roll and operative to provide an output signal indicative of the magnitude of a third roll parameter selected from the rotational speed and the shaft torque of said third tension roll, said third sensor also being operatively coupled to said third variable speed control motor to cause variation in the speed of said third control motor in response to variation in the magnitude of said third roll parameter thereby automatically to adjust the speed of the main drive output of said third differential and consequently the speed of said fourth tension roll driven thereby automatically in response to variation in the magnitude of said third roll parameter.

Claim 5

A tension roll assembly as claimed in claim 3 which additionally comprises first, second and third, manually operable controls operatively connected between respective ones of said first, second and third sensors and respective ones of said first, second and third variable speed control motors whereby the speeds of the main drive outputs of respective ones of said first, second and third differentials and consequently the speeds of respective ones of said second, third and fourth tension rolls driven thereby can also be manually and individually adjusted.

Claim 6

A tension roll assembly as claimed in claim 1 and which additionally comprises a first manually operable control operatively connected between said first sensor and said first variable speed control motor whereby the speed of the main drive output of said first differential and consequently the speed of said second tension roll can also be manually adjusted.

Claim 7

A tension roll assembly as claimed in claim 3 and in which said first, second, third and fourth tension rolls constitute a first bridle of tension rolls and which assembly further comprises: a second bridle of tension rolls comprising fifth, sixth, seventh and eighth tension rolls around and between which the sheet metal strip runs, such strip passing directly from said first tension roll of said first bridle to said fifth tension roll of said second bridle; a second bridle drive transmission including fifth, sixth, seventh and eighth roll drive transmission and extending between said motive power source and said second bridle to cause rotation of respective ones of said fifth, sixth, seventh, and eighth tension rolls on operation of said motive power source; fourth, fifth and sixth differentials, each including a main drive input, a main drive output and a control drive input and being operatively coupled in respective ones of said sixth, seventh and eighth roll drive transmissions to transmit drive motion from said second bridle drive transmission to respective ones of said sixth, seventh and eighth tension rolls of said second bridle at variable speeds depending on the magnitudes of the control drives to respective ones of said differentials; fourth, fifth and sixth variable speed control motors operatively coupled to said control drive inputs of respective ones of said fourth, fifth and sixth differentials; fourth, fifth and sixth sensors coupled to respective ones of said fifth, sixth and seventh tension rolls and operative to provide output signals indicative of the magnitudes of roll parameters selected from the rotational speeds and the shaft torques of respective ones of said fifth, sixth and seventh tension rolls, said sensors also being operatively coupled to respective ones of said fourth, fifth and sixth variable speed control motors to cause variations in the speeds of said control motors in response to variations in the magnitudes of respective ones of said parameters, thereby automatically to adjust the speeds of the main drive outputs of respective ones of said fourth, fifth and sixth differentials and consequently the speeds of respective ones of said sixth, seventh and eighth tension rolls automatically in response to variations in the magnitudes of respective ones of said roll parameters; a bridle drive differential including a main driVe input, a main drive output and a control drive input, said bridle drive differential being operatively coupled in said second bridle drive transmission to transmit drive motion from said motive power source to said fifth, sixth, seventh and eighth roll drive transmissions at a variable speed depending on the magnitude of the control drive to said bridle drive differential; a seventh variable speed control motor operatively coupled to said control drive input of said bridle drive differential; and a control means operatively connected to said seventh variable speed control motor and to each of said first and fourth sensors and adapted to provide an output signal indicative of the difference in magnitude of said roll parameters of said first and fifth tension rolls thereby automatically to adjust the speed of the main drive output of said bridle drive differential and consequently the speeds of all of said fifth, sixth, seventh and eighth tension rolls in response to variations in the magnitude of said difference.

Claim 8

A tension roll assembly as claimed in claim 6 and which additionally comprises first, second, third, fourth, fifth and sixth manually operable controls connected between respective ones of said first, second, third, fourth, fifth and sixth sensors and respective ones of said first, second, third, fourth fourth, fifth and sixth variable speed control motors whereby the speeds of respective ones of said second, third, fourth, sixth, seventh and eighth tension rolls can also be manually and independently adjusted.

Claim 9

A tension roll assembly as claimed in claim 1 and including: first and second bridles each in turn including a plurality of tension rolls about and between which the sheet metal strip runs, said first and second tension rolls forming part of said first bridle; a first bridle drive transmission including said first and second roll drive transmissions; a second bridle drive transmission operatively extending between said motive power source and said tension rolls of said second bridle to cause rotation of said rolls; a bridle drive differential including a main drive input, a main drive output and a control drive input, said bridle drive differential being operatively coupled in said second bridle drive transmission to transmit drive motion from said motive power source to said tension rolls of said second bridle at a variable speed depending on the magnitude of the control drive to said bridle drive differential; a second variable speed control motor operatively coupled to said control drive input of said bridle drive differential; a second sensor coupled to a selected one of said tension rolls of said second bridle and operative to provide a signal indicative of the magnitude of a roll parameter selected from the rotational speed and the shaft torque of said selected one of said tension rolls of said second bridle; a control means operatively coupled to said first and second sensors to provide an output signal indicative of the difference between the magnitudes of said parameters as provided by said first and second sensors, said control means also being operatively coupled to said second variable speed control motor to cause variation of the speed of said second variable speed control motor in response to variation in the magnitude of said difference thereby automatically to adjust the speed of the main drive output of said bridle drive differential and consequently the speeds of said tension rolls of said second bridle.

Claim 10

A tension roll assembly as claimed in claim 8 in which said first tension roll is a terminal roll of said first bridle and in which said second sensor is coupled to a tension roll of said second bridle operatively adjacent said first tension roll.

Claim 11

A tension roll assembly as claimed in claim 1 in which said first and second roll drive transmissions jointly comprise a drive-dividing mechanism, a first drive sub-transmission extending from said motive power source to said drive-diViding mechanism, a second drive sub-transmission extending from said drive-dividing mechanism to said first tension roll and a third drive sub-transmission extending from said drive-dividing mechanism to said second tension roll, in which said first sensor is coupled to said first drive sub-transmission to provide an output signal indicative of the magnitude of one parameter selected from the rotational speed and shaft torque of said first drive sub-transmission, and in which said first differential is operatively coupled in said third drive subtransmission.

Claim 12

A tension roll assembly as claimed in claim 10 which additionally comprises a third tension roll about which the sheet metal strip runs; a fourth drive sub-transmission extending from said drive-dividing mechanism to said third tension roll to cause rotation of said third tension roll on operation of said motive power source; a second differential including a main drive input, a main drive output and a control drive input, said second differential being operatively coupled in said fourth drive subtransmission; a second variable speed control motor operatively coupled to said control drive input of said second differential; a control operatively coupled between said first sensor and each of said first and second variable speed control motors and adapted automatically to cause variation in the speeds of said control motors in response to variation in the magnitude of said parameter, thereby automatically to adjust the speeds of said third and fourth drive sub-transmissions and consequently the speeds of said second and third tension rolls driven thereby automatically in response to variations in the magnitude of said parameter.

Claim 13

A tension roll assembly as claimed in claim 11 in which said control is adapted to adjust the speeds of said third and fourth drive sub-transmissions to predetermined relative extents in response to variations in the magnitude of said parameter.