Device for conveying articles to be sewed

Abstract

The invention relates to a device for conveying articles to be sewed, which is provided for a sewing device or sewing machine. Said device comprises at least one material advancing device for advancing the article to be sewed in the advancing direction of the material with an advancing speed defined by the speed of the machine and by the stitch length. The device also comprises at least one material conveying supplementary device which, in the form of a pressing means, subjects the upper material layer of the article to be sewed to a pressing force. The material conveying supplementary device rotates with a rotational speed, is arranged behind the material advancing device in the advancing direction of the material and can be proportionally driven with regard to the speed of the machine and to the stitch length. At least one device can increase the pressing force, which is exerted by the device onto the upper material layer of the article to be conveyed, with an increasing speed of the machine and/or in addition to the proportional increase with increasing speed of the machine, can further increase the rotational speed of the material conveying supplementary device.

1 . Device intended for a sewing means ( 10 ) or sewing machine ( 10 ) for transport of sewn material, having 
 at least one feeder means ( 1 ) for advancing the sewn material in the material feed direction (D) with an advance rate which is determined by the machine rpm (n) and by the stitch length (L) and    at least one auxiliary material transport means ( 2 ) which acts on the upper layer ( 8 ) of the sewn material in the form of a pressure means with a pressure force (F p ), which rotates with a peripheral speed (U p ), and which is located in the material feed direction (d) behind the feeder means ( 1 ) and can be driven in proportion to the machine rpm (n) and to the stitch length (L), characterized in that    by at least one means ( 3 )    the pressure force (F p ) which is exerted by the auxiliary material transport means ( 2 ) on the upper layer ( 8 ) of the sewn material to be transported can be increased with increasing machine rpm (n) and/or    the peripheral speed (U p ) of the auxiliary material transport means ( 2 ) can be further increased in addition to the proportional increase with increasing machine rpm (n).    
     
     
         2 . Device as claimed in  claim 1 , wherein the pressure force (F p ) and/or the peripheral speed (U p ) can be adapted preferably by the means  3  in addition to the composition of the sewn material which is to be transported.  
     
     
         3 . Device as claimed in  claim 1  or  2 , wherein the pressure force (F p ) is given by the equation 
       
         F 
         p 
         =F 
         0 
         +R×n 
       
       in which 
 F 0  is a constant force;  
 R is the coefficient of friction with a magnitude which is determined by the friction ratios between the auxiliary material transport means ( 2 ) and the upper material layer ( 8 ); and  
 n is the machine rpm.  
 
     
     
         4 . Device as claimed in at least one of  claims 1  to  3 , wherein the rpm (n p ) of the means ( 3 ) is a measure of the peripheral speed (U p ) of the auxiliary material transport means ( 2 ) or is equal to the peripheral speed (U p ) of the auxiliary material transport means ( 2 ), the rpm (n p ) of the means ( 3 ) being given by the equation 
       
         n 
         p 
         =k×n×L, 
       
       in which 
 k is a matching factor;  
 n is the machine rpm;  
 L is the stitch length  
 
     
     
         5 . Device as claimed in at least one of  claims 1  to  4 , wherein the auxiliary material transport means ( 2 ) in low rpm ranges (n p <500 min −1 ) of the means ( 3 ) operates in the intermittent mode, the on and off times of the means ( 3 ) being preferably determined by the angular position (φ) of the main shaft of the sewing means ( 10 ) or sewing machine ( 10 ).  
     
     
         6 . Device as claimed in at least one of  claims 1  to  5 , wherein the auxiliary material transport means ( 2 ) in high rpm ranges (n p >500 min −1 ) of the means ( 3 ) operates in a continuous mode.  
     
     
         7 . Device as claimed in at least one of  claims 1  to  6 , wherein the transport path of the auxiliary material transport means ( 2 ) per stitching process is greater, especially slightly greater, than the advance path of the feeder means ( 1 ).  
     
     
         8 . Device as claimed in at least one of  claims 1  to  7 , wherein there is at least one electronic control means ( 4   a  and  4   b ) for controlling the pressure force (F p ) of the auxiliary material transport means ( 2 ) and/or the rpm (np) of the means ( 3 ), 
 in which especially the machine rpm (n) can be determined and/or,  
 which receives especially information about the stitch length (L) by input by means of at least one control panel ( 5 ) or which receives especially information about the composition of the sewn material to be transported by input by means of at least one control panel ( 5 ).  
 
     
     
         9 . Device as claimed in at least one of  claims 1  to  8 , wherein the means ( 3 ) has at least one linear motor ( 30 ) which is operated preferably with direct current, and which preferably has at least one stator element ( 31 ) which is made as a housing and in which preferably at least one rotor element ( 32 ) made as a drive rod is supported.  
     
     
         10 . Device as claimed in  claim 4  and as claimed in  claim 9 , wherein the matching factor (k) is given by the formula 
         k=k   1   ×k   2   ×k   3 , k 1  being the parameter for the diameter of the auxiliary material transport means ( 2 ), for the constant of the linear motor ( 30 ) and for the stepping-down of the gear ( 34 );    k 2  being a measure for the functional dependency of the offset between the upper material layer ( 8 ) and the lower material layer ( 9 ) on the machine rpm (n); and    k 3  being the parameter for the composition of the sewn material to be transported.    
     
     
         11 . Device as claimed in  claim 9  and as claimed in  claim 10 , wherein the means ( 3 ) has at least one carrier element ( 36 ) which is connected to the rotor element ( 32 ), 
 to which the drive motor ( 33 ), the gear ( 34 ) and the transfer element ( 35 ) are attached; and/or  
 which is preferably supported locked by means of at least one guide rod ( 37 ).  
 
     
     
         12 . Device as claimed in  claim 11 , wherein the carrier element ( 36 ) is pretensioned by at least one elastic, low-mass coupling element ( 38 ), especially by means of at least one helical spring.