Sewing Machine Drive

Abstract

A magnetic encoder system of a sewing machine drive comprises a magnetic, magnetised disc with alternating north and south pole elements, which are used as incremental markings. The latter are designed as a full ring-incremental track, which extends around a circumference of the ferritic disc, and as an annular section incremental track, which is designed as an annular section on the ferritic disc. The result is a magnetic encoder system for a servomotor of a sewing machine.

1 . A sewing machine drive with a magnetic encoder system comprising:
 a disc made from magnetic material, wherein the disk is magnetised with alternating north and south pole elements, wherein the alternating north and south pole elements define incremental markings, a full ring incremental track, having incremental markings comprised of alternating north and south pole elements and arranged as a ring over 360° along a circumference of the disc and an additional annular section incremental track, having incremental markings comprised of alternating north and south pole elements and arranged as an annular section on the disc.   
     
     
         2 . The sewing machine drive according to  claim 1  wherein the full ring incremental track is used for determining the position and speed information. 
     
     
         3 . The sewing machine drive according to  claim 1 , wherein the annular section incremental track is used for zero point referencing. 
     
     
         4 . The sewing machine drive according to  claim 1 , further comprising an evaluation unit with integrated microcontroller and magnet sensors performs the evaluation of the full ring incremental track. 
     
     
         5 . The sewing machine drive according to  claim 1 , wherein a further, separate magnet sensor is used to detect the annular section incremental track. 
     
     
         6 . The sewing machine drive according to  claim 1  wherein one of the full ring incremental track and annular section incremental track is disposed radially outwardly of the other one of the full ring incremental track and annular section incremental track. 
     
     
         7 . The sewing machine drive according to  claim 6 , further comprising an evaluation unit comprised of a plurality of magnet sensors with one of the magnet sensors detecting the full ring incremental track and another one of the magnet sensors detecting the annular section incremental track. 
     
     
         8 . The sewing machine drive according to  claim 7 , wherein the evaluation unit is equipped with a microcontroller. 
     
     
         9 . The sewing machine drive according to  claim 7 , further comprising a rotary sewing machine drive shaft generally coaxial with one of the full ring incremental track and annular section incremental track. 
     
     
         10 . The sewing machine drive according to  claim 1 , further comprising a rotary sewing machine drive shaft about which the full ring incremental track generally coaxially extends. 
     
     
         11 . The sewing machine drive according to  claim 10 , wherein the annular section incremental track is disposed radially inwardly of the full ring incremental track between the full ring incremental track and the sewing machine drive shaft. 
     
     
         12 . The sewing machine drive according to  claim 11 , further comprising an evaluation unit comprised of a plurality of magnet sensors with one of the magnet sensors detecting the full ring incremental track and another one of the magnet sensors detecting the annular section incremental track. 
     
     
         13 . The sewing machine drive according to  claim 1 , further comprising: (a) a servomotor driven rotary sewing machine drive shaft about which (i) the full ring incremental track generally coaxially extends, and (ii) the annular section incremental track generally annularly extends, and (b) a processor-equipped evaluation unit comprised of a plurality of magnet sensors with one of the magnet sensors detecting alternating north and south poles of the full ring incremental track and another one of the magnet sensors detecting alternating north and south poles of the annular section incremental track. 
     
     
         14 . The sewing machine drive according to  claim 1 , further comprising: (a) a servomotor driven rotary sewing machine drive shaft about which (i) the full ring incremental track generally coaxially extends, and (ii) the annular section incremental track generally annularly extends, and (b) an evaluation unit configured to detect (i) north and south pole elements of the full ring incremental track, and (ii) north and south pole elements of the annular section incremental track. 
     
     
         15 . The sewing machine drive according to  claim 14 , wherein the disc is carried by the sewing machine drive shaft for rotation of the disc, the full ring incremental track, and the annular section incremental track substantially in unison therewith; and wherein the evaluation unit is mounted stationary relative to the sewing machine drive shaft, the full ring incremental track, and the annular section incremental track. 
     
     
         16 . The sewing machine drive according to  claim 15 , wherein the evaluation unit is configured to detect (i) north and south pole elements of the full ring incremental track for determining position and speed information thereof, and (ii) detecting north and south pole elements of the annular section incremental track for determining a zero point reference therefor. 
     
     
         17 . The sewing machine drive according to  claim 16 , wherein the evaluation unit comprised of a plurality of magnet sensors with one of the magnet sensors detecting north and south pole elements of the full ring incremental track for determining position and speed information thereof, and another one of the magnet sensors detecting north and south pole elements of the annular section incremental track for determining a zero point reference position therefor. 
     
     
         18 . A sewing machine drive with a magnetic encoder system comprising:
 (a) a servomotor-driven rotary sewing machine drive shaft;   (b) a disc comprising a full ring incremental track comprised of alternating north and south pole elements defining one set of incremental markings, and an annular section incremental track comprised for alternating north and south pole elements defining another set of incremental markings; and   (c) an evaluation unit configured to detect north and south pole elements of the full ring incremental track and north and south pole elements of the annular section incremental track during rotation of the sewing machine drive shaft.   
     
     
         19 . The sewing machine drive according to  claim 18 , wherein the disc is carried by the sewing machine drive shaft for rotation of the disc, the full ring incremental track, and the annular section incremental track substantially in unison with the sewing machine drive shaft; and wherein the evaluation unit is mounted stationary relative to the sewing machine drive shaft, the full ring incremental track, and the annular section incremental track. 
     
     
         20 . The sewing machine drive according to  claim 19 , wherein the evaluation unit is comprised of a plurality of magnet sensors with one of the magnet sensors detecting north and south pole elements of the full ring incremental track for determining position and speed information thereof, and another one of the magnet sensors detecting north and south pole elements of the annular section incremental track for determining a zero point reference position therefor.