Transfer of a flexible web member from supply reel to a take-up reel

A method of monitoring the transfer of a web from reel to reel of a web/reel assembly, in apparatus operable with web/reel assemblies of different types each characterized by known physical parameters, said apparatus having reel speed detectors, said method comprising the steps of:

• storing in memory for each of a plurality of web/reel assemblies of one known type or of another known type, signals representing a set of corresponding constants uniquely characterizing the respective web/reel assembly and derived from the physical parameters thereof, which set of constants when used in web position determination algorithms with the ratio of reel speeds measured anywhere along the length of the web provides absolute values of web position relative to one end of the web of an intermediate portion of the web being transferred from one reel to the other,
• measuring the ratio between the reel speeds provided by said detectors,
• designating that the web/reel assembly in the apparatus is of one known type or of another known type,
• deriving the set of constants corresponding to the designated web/reel assembly from said signals stored in memory,
• determining the position relative to one end of the web of an intermediate portion of the web being transferred from one reel to the other, using said web position determination algorithms with the derived constants and the measured ratio of reel speeds, and
• monitoring the transfer of the web according to said determined position.

A method of controlling the transfer of tape from reel to reel in tape/reel assemblies, said apparatus having drive means for the tape controllable to vary the speed of tape movement, and reel speed detectors, said method comprising the steps of:

• measuring at successive intervals the ratio of speeds of the reels provided by said detectors,
• determining successive tape positions as the tape is moved from reel to reel, based on the ratio of reel speeds measured at said intervals,
• manually entering a target tape position predetermined by the operator,
• controlling said drive means to carry out a search sequence of tape movement, including engaging said drive means to move said tape toward a target tape position at a first speed,
• comparing successive determined tape positions with a predetermined target position as the tape moves toward said target position,
• controlling said drive means further in said search sequence to shift from said first to a slower speed upon movement of the tape to a determined tape position spaced a known distance ahead of said predetermined target position, and
• controlling said drive means to complete the search sequence and stop the tape upon movement of the tape said known distance to the predetermined target position.

A tape transport apparatus for cassettes having two reels carrying tape, said apparatus being operable with cassettes of different known types, each having different known lengths of tape and comprising drive means for moving the tape from reel to reel in a cassette in the apparatus, reel speed detectors, controller means connected to said reel speed detectors and said drive means, and means designating for the controller means the type of cassette in the apparatus, said controller means including

• means for periodically measuring the ratio of speeds of the reels provided by said detectors,
• means determining absolute values of successive tape positions as tape is moved from reel to reel using tape position determination algorithms employing constants for the cassette in the apparatus and said measured ratios of rotational speeds of the reels;
• dedicated memory means storing for each of a plurality of known types of cassettes, a set of corresponding constants used in said position determination algorithms, and
• means deriving the set of constants from said memory means corresponding to the designated cassette, for said controller means to employ in said algorithms for determining successive tape positions.

In a tape transport apparatus for cassettes having two reels carrying tape, said apparatus being operable with cassettes having different known lengths of tape, and having drive means for moving the tape from reel to reel, means for generating pulses representing the rotational speeds of the reels upon tape movement, and controller means receiving said reel pulses and providing for each such cassette absolute determinations of successive tape positions using tape position determination algorithms employing constants for the cassette in the apparatus and the ratio of rotational speeds of the reels measured from said reel pulses as the tape is transferred from one reel to the other, the combination in said controller means comprising:

• means including registers receiving and counting reel pulses, for measuring at successive intervals the ratio of rotational speeds of said reels based on the counts in said registers,
• dedicated memory means storing for each of a plurality of cassettes having tapes of one known length or of another known length, a set of corresponding constants used in said position determination algorithms,
• means deriving from said memory means the set of constants corresponding to the cassette loaded in the apparatus,
• means determining successive tape positions using said tape position determination algorithms with said set of constants corresponding to the cassette loaded in the apparatus and speed ratios of said reels measured at successive intervals, and
• means controlling said drive means to monitor the tape movement according to said successive determined tape positions.

Transport apparatus for web/reel assemblies which may be loaded into and removed from the apparatus, said reel/web assemblies having two reels carrying lengths of web, and determining for said web/reel assemblies absolute values of the position of a web portion relative to one end of the web, using web position determination algorithms employing constants established by physical parameters including length of web for the web/reel assembly loaded in the apparatus and the ratio of rotational speeds of the reels as the web portion is being transferred from one reel to the other, said tape transport apparatus comprising:

• means generating pulses representing the rotational speeds of the reels,
• means including registers for receiving and counting said pulses, and measuring the continuously changing ratio of rotational speeds of said reels as the web is transferred from reel to reel based on the counts in said registers,
• dedicated memory means storing for each of a plurality of web/reel assemblies of the same type having webs of one known length or of another known length, a set of corresponding constants used in said web position determination algorithms,
• means for designating that the web/reel assembly loaded in the apparatus has a web of one known length or of another known length, and deriving from said memory means the set of constants corresponding to a designated assembly,
• computer circuit means determining the successive positions relative to one end of the web of successive portions of the web as said portions are transferred from one reel to the other, using said web position determination algorithms with the set of constants from said memory means corresponding to the designated web/reel assembly and the rotational speed ratio of said reels measured as said portions are transferred, said computer circuit means including means producing output signals representing the position determined for each successive web portion, and
• a display unit connected to said circuit means and displaying the successive positions represented by said output signals to reflect the continuous changes in position of the web as it is transferred from reel to reel.

In a tape transport apparatus for tape/reel assemblies having two reels, said apparatus having drive means for the tape controllable to vary the speed of tape movement, and reel speed detectors, the combination comprising:

• a controller connected to said reel speed detectors and said tape drive means,
• means provided by said controller for measuring at successive intervals the ratio of speeds of the reels provided by said detectors, and determining successive tape positions as the tape is moved from reel to reel at various speeds, based on the ratio of reel speeds measured at said intervals,
• manually operable numberic data input means for entering a target tape position predetermined by the operator into said controller,
• manually operable means including a search switch activating said controller to control said drive means to carry out a search sequence of tape movement, including engaging said drive means to move said tape toward a target tape position at a first speed, and
• means provided by said controller for comparing successive determined tape positions with a predetermined target position as the tape moves toward said target position, said controller being operative in said search sequence to control said drive means responsive to said comparing means and shift said drive means from said first to a slower speed upon movement of the tape to a determined tape position spaced a known distance ahead of said predetermined target position, and to stop the tape upon movement of the tape said known distance to the predetermined target position.