Synchronized line feed tensioning and gripping apparatus for printer

Claim 2

In an apparatus including a mechanism for alternately advancing a web a predetermined distance, and for stopping the web for a predetermined period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for firmly gripping and holding a web in a fixed position during those periods when not positively advanced, said assembly including: cam means coupled to and movable in response to actuation of said web advancing mechanism, said cam means having a plurality of alternately spaced protuberances and arcuate recesses formed along the periphery thereof, said cam means being positioned adjacent to the web so that at least one protuberance thereof is moved along an arcuate path into periodic contact with one side of said web: means for causing the time of periodic contact to coincide with said predetermined period, and web engaging means positioned on the side of the web opposite said cam means, and in alignment with the latter, the position and dimensions of said web engaging means being chosen relative to the path of movement of, and the dimensions of the recesses and protuberances in, said cam means such that when each successive protuberance of said cam means is brought at least into its closest proximity with said web engaging means, the web is firmly gripped therebetween.

Claim 3

In an apparatus including a mechanism for alternately advancing a web a predetermined distance, and for stopping the web for a predetermined period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for maintaining tension on a web while being advanced, and for firmly gripping and holding the web in a fixed position under tension during those periods when not positively advanced, said assembly including: rotatable cam means coupled to and rotated in response to actuation of said web advancing mechanism, said cam means having a plurality of alternately spaced protuberances and arcuate recesses formed along the periphery thereof, said cam means being positioned so that at least one protuberance thereof is moved along an arcuate path into contact with one side of the web: means for causing the time of periodic contact to coincide with said predetermined period, and rotatable web engaging and tensioning means positioned in contact with the side of the web opposite said rotatable cam means, and in alignment with the latter, the axis and dimensions of said web engaging and tensioning means being chosen relative to both the axis of, and the dimensions of the recesses and proturberances in, said rotatable cam means such that when each successive protuberance of said cam means is moved at least into its closest proximity with said rotatable web engaging and tensioning means, the web is firmly gripped therebetween.

Claim 4

In an apparatus including a mechanism for alternately advancing a web a predetermined distance, and for stopping the web for a predetermined period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for maintaining tension on a web while being advanced, and for firmly gripping and holding the web in a fixed position under tension during those periods when not positively advanced, said assembly including: rotatable cam means coupled to and rotated in response to actuation of said web advancing mechanism, said cam means having a plurality of alternately spaced protuberances and arcuate recesses formed along the periphery thereof, said cam means being positioned so that at least one protuberance thereof is moved along an arcuate path into contact with one side of the web: means for causing the time of periodic contact to coincide with said predetermined period, and rotatable web engaging and tensioning means positioned in contact with the side of the web opposite said rotatable cam means, and in alignment with the latter, the axis and dimensions of said web engaging and tensioning means being chosen relative to both the axis of, and the dimensions of the recesses and proturberances in, said rotatable cam means such that when each successive protuberance of said cam means is moved at least into its closest proximity with said rotatable web engaging and tensioning means, the web is firmly gripped therebetween.

Claim 5

In an apparatus in accordance with claim 2, said rotatable cam means comprising at least two rotatable pinch cams adjustably mounted on a common drive shaft coupled to said web advancing means, said pinch cams being sPaced apart so as to coincide with opposite marginal edge regions of the web, and said rotatable engaging and tensioning means comprising at least two rotatable pinch rollers respectively aligned with said pinch cams.

Claim 6

In an apparatus in accordance with claim 3, said common shaft comprising a spline shaft which allows said pinch cams mounted thereon to be adjustably spaced for different web widths, and said web advancing mechanism comprising a spaced pair of tractors, with belt carried feed pins, coupled to and adjustably spaced along said spline shaft for advancing a web having a row of perforations formed along and near each marginal edge thereof, with the perforations being dimensioned and spaced for registration with said aligned drive pins.

Claim 7

In a printer including a line feed mechanism for alternately advancing a web at least one predetermined line space at a time, and for stopping the web for a predetermined line printing period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for maintaining tension on said web while being advanced, and for firmly gripping and holding said web in a fixed position under tension during each line printing period, said assembly including: rotatable pinch cam means coupled to and rotated in response to an actuation of said line feed mechanism, said pinch cam means having a plurality of spaced protuberances with arcuate peripheral wall portions, each having a common maximum radius, with adjacent protuberances being separated by arcuate recesses so as to define a scalloped periphery, said pinch cam means being positioned adjacent to the web so that the arcuate peripheral wall portion of at least one protuberance thereof periodically contacts one side of said web, and moves in the same direction as said web when said web is moving: means for causing the time of periodic contact of said at least one protuberance to coincide with said predetermined period, and rotatable pinch roller tensioning means positioned in contact with the side of the web opposite said pinch cam means, and being in alignment with the latter, the axis and dimensions of said rotatable pinch roller tensioning means being chosen relative to both the axis of, and the dimensions of said recesses and protuberances in, said pinch cam means such that when each successive arcuate peripheral wall portion of said pinch cam means is rotated at least into its closest proximity with said pinch roller tensioning means, defined by a plane bisecting the axes thereof, said web is firmly gripped under tension therebetween.

Claim 8

In a printer including a line feed mechanism for alternately advancing a web at least one predetermined line space at a time, and for stopping the web for a predetermined line printing period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for maintaining tension on said web while being advanced, and for firmly gripping and holding said web in a fixed position under tension during each line printing period, said assembly including: rotatable pinch cam means coupled to and rotated in response to an actuation of said line feed mechanism, said pinch cam means having a plurality of spaced protuberances with arcuate peripheral wall portions, each having a common maximum radius, with adjacent protuberances being separated by arcuate recesses so as to define a scalloped periphery, said pinch cam means being positioned adjacent to the web so that the arcuate peripheral wall portion of at least one protuberance thereof periodically contacts one side of said web, and moves in the same direction as said web when said web is moving: means for causing the time of periodic contact of said at least one protuberance to coincide with said predetermined period, and rotatable pinch roller tensioning means positioned in contact with the side of the web opposite said pinch cam means, and being in alignment with the latter, the axis and dimensions of said rotatable pinch roller tensioning means being chosen relative to both the axis of, and the dimensions of said recesses and protuberances in, said pinch cam means such that when each successive arcuate peripheral wall portion of said pinch cam means is rotated at least into its closest proximity with said pinch roller tensioning means, defined by a plane bisecting the axes thereof, said web is firmly gripped under tension therebetween.

Claim 9

In a printer in accordance with claim 5, said rotatable pinch cam means comprising at least two rotatable pinch cam adjustably mounted on a common drive shaft coupled to said line feed mechanism, said pinch cams being spaced apart so as to coincide with opposite marginal edge regions of the web, and said pinch roller means comprising at least two rotatable pinch rollers and tensioning respectively aligned with said pinch cams, and with each having at least a resilient peripheral surface.

Claim 10

In a printer in accordance with claim 6, said assembly further including adjustable spring biasing means for loading each of said pinch rollers so as to control the amount of tension exerted on a web while the latter is being advanced and drawn over said pinch rollers without being positively engaged by said rotatable pinch cams.

Claim 11

In a printer in accordance with claim 7, the width of the arcuate peripheral portion of each of said protuberances formed in each of said pinch cams, as measured along the circumference thereof, being sufficiently great to cause each successive protuberance to be brought into contact with, and pinch said web firmly against the aligned one of said pinch rollers for short predetermined periods of time at the end of and at the beginning of the line feed advancement periods respectively preceeding and following each predetermined line printing period, whereby said pinch cams and pinch rollers not only firmly grip the web, but positively advance the web independently of said line feed mechanisms.

Claim 12

In a printer in accordance with claim 8, said common shaft comprising a spline shaft which allows said pinch cams mounted thereon to be adjustably spaced for different web widths, and said line feed mechanism comprising a spaced pair of tractors, with belt carried feed pins, coupled to and adjustably spaced along said spline shaft for advancing a web having a row of perforations formed along and near each marginal edge thereof, with the perforations being dimensioned and spaced for registration and with aligned drive pins.

Claim 13

In a printer including a type character print mechanism and a line feed mechanism for alternately advancing a web at least one predetermined line space at a time, and for stopping the web for a predetermined line printing period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for applying adjustable tension on said web while being advanced, and for firmly gripping and holding said web in a fixed position under tension during each line printing period, said assembly including: a pair of rotatable pinch cams coupled to and rotated in response to the actuation of said line feed mechanism, said pinch cams being spaced apart so as to be respectively positioned near the opposite longitudinal edges of said web in the immediate area of said print mechanism, said pinch cams each having a plurality of spaced protuberances with arcuate peripheral wall portions, each having a common maximum radius, with adjacent protuberances being separated by arcuate recesses so as to define a scalloped periphery, each of said pinch cams being positioned adjacent to said web such that the arcuate peripheral wall portion of at least one protuberance thereof contacts one side of said web and moves in the same direction as said web when said web is moving: means for causing the time of periodic contact of said at least one protuberance to coincide with said predetermined period, and a pair of rotatable pinch and tensioning rollers, each having at least a resilient peripheral surface, respectively positioned in contact with the side of said web opposite a different one of said pinch cams, and being in alignment with the latter, the axis and dimensions of each rotatable pinch and tensioning roller being chosen relative to both the axis of, and the dimensions of said recesses and protuberances in, said associated pinch cam such that when each successive arcuate peripheral wall portion of said associated pinch cam is rotated at least into its closest proximity with said aligned pinch and tensioning roller, defined by a plane bisecting the axes thereof, said web is firmly gripped under tension therebetween.

Claim 14

In a printer including a type character print mechanism and a line feed mechanism for alternately advancing a web at least one predetermined line space at a time, and for stopping the web for a predetermined line printing period, with both normally occurring in a relatively rapid, repetitive manner, the combination further comprising: an assembly for applying adjustable tension on said web while being advanced, and for firmly gripping and holding said web in a fixed position under tension during each line printing period, said assembly including: a pair of rotatable pinch cams coupled to and rotated in response to the actuation of said line feed mechanism, said pinch cams being spaced apart so as to be respectively positioned near the opposite longitudinal edges of said web in the immediate area of said print mechanism, said pinch cams each having a plurality of spaced protuberances with arcuate peripheral wall portions, each having a common maximum radius, with adjacent protuberances being separated by arcuate recesses so as to define a scalloped periphery, each of said pinch cams being positioned adjacent to said web such that the arcuate peripheral wall portion of at least one protuberance thereof contacts one side of said web and moves in the same direction as said web when said web is moving: means for causing the time of periodic contact of said at least one protuberance to coincide with said predetermined period, and a pair of rotatable pinch and tensioning rollers, each having at least a resilient peripheral surface, respectively positioned in contact with the side of said web opposite a different one of said pinch cams, and being in alignment with the latter, the axis and dimensions of each rotatable pinch and tensioning roller being chosen relative to both the axis of, and the dimensions of said recesses and protuberances in, said associated pinch cam such that when each successive arcuate peripheral wall portion of said associated pinch cam is rotated at least into its closest proximity with said aligned pinch and tensioning roller, defined by a plane bisecting the axes thereof, said web is firmly gripped under tension therebetween.

Claim 15

In a printer in accordance with claim 10, said rotatable pinch cams being mounted on and adjustably spaced along a common, laterally disposed drive spline, and said line feed mechanism comprising a spaced pair of tractors, with belt carried feed pins, coupled to and adjustably spaced along said spline shaft for advancing a web having a row of perforations formed along and near each marginal edge thereof, with the perforations being dimensioned and spaced for registration with said aligned drive pins.

Claim 16

In a printer in accordance with claim 11, each of said rotatable pinch and tensioning rollers being mounted on a stub shaft secured to a pivotal housing member of a different one of said tractors.

Claim 17

In a printer in accordance with claim 12, the pivotal housing member of each of said tractors comprising a spring biased hold-down plate for the web passing thereunder, said plate when in its normal position spring biasing the one of said pinch and tensioning rollers supported thereon to the desired position relative to said associated pinch cam, and with each of said pinch and tensioning rollers being adjustably spring loaded so as to control the tension exerted on said web at least during the major portion of the time when said web is advanced thereover.