Sewing machine

Abstract

A sewing machine includes a supporting plate portion and a needle. The supporting plate portion contacts sewing fabric that is moved in a predetermined direction during a sewing operation. The needle is vertically moved between a top dead center above the supporting plate portion and a bottom dead center below the supporting plate portion. The supporting plate portion has a needle hole through which the needle passes. The lower end opening of the needle hole is larger than the upper end opening.

1 . A sewing machine having a sewing fabric supporting plate and a needle, 
 wherein the sewing fabric supporting plate has a supporting plate portion that contacts sewing fabric fed in a predetermined direction during a sewing operation, thereby supporting the fabric, wherein the supporting plate portion has a needle hole through which the needle passes through;    wherein the needle is vertically moved between a top dead center above the supporting plate and a bottom dead center below the supporting plate portion; and    wherein the needle hole is formed such that a lower end opening is smaller than an upper end opening.    
     
     
         2 . The sewing machine according to  claim 1 , wherein the vertical cross-section of the needle hole is tapered downward.  
     
     
         3 . The sewing machine according to  claim 1 , wherein a through hole is formed in the supporting plate portion, and a fitted member is fitted to the through hole, and wherein the needle hole is formed in the fitted member.  
     
     
         4 . The sewing machine according to  claim 3 , wherein the fitted member is formed of a material having a higher hardness than that of the supporting plate portion.  
     
     
         5 . The sewing machine according to  claim 3 , wherein the fitted member is made of steel, and wherein the supporting plate portion is made of aluminum or an aluminum alloy.  
     
     
         6 . A lower thread supply control apparatus for a sewing machine, wherein, in synchronization with vertical movements of needle through which an upper thread is drawn, a blade portion of a looper through which a lower thread is drawn is moved back and forth to form predetermined stitches on sewing fabric, wherein the lower thread supply control apparatus controls the supply state of the lower thread such that the lower thread drawn from a lower thread supply source is supplied in a predetermined state, the apparatus comprising: 
 a lower thread guide, through which the lower thread passes through such that the lower thread is supplied from the lower thread supply source to the looper by way of a predetermined lower thread path; and    a lower thread interfering member, which is capable of engaging with the lower thread passing through the lower thread guide, and constantly moves toward a predetermined end of movement,    wherein, when the lower thread interfering member engages with the lower thread, the lower thread passes through the lower thread guide while being pressed against the lower thread guide.    
     
     
         7 . The lower thread supply control apparatus for a sewing machine according to  claim 6 , wherein the lower thread interfering member pivots about a proximal rotation center, wherein, when the lower thread interring member pivots, a lower thread engaging portion provided at a distal end of the lower thread interfering member moves along a rotation path that intersects the lower thread path.  
     
     
         8 . The lower thread supply control apparatus for a sewing machine according to  claim 6 , further comprising: a detection device, wherein, when the lower thread interfering member reaches the end of movement, the detection device outputs a cut thread detection signal; and a controller, which stops operation of the sewing machine based on the output of a cut thread detection signal from the detection device.  
     
     
         9 . The lower thread supply control apparatus for a sewing machine according to  claim 7 , wherein the lower thread interfering member has a weight member located in the vicinity of the lower thread engaging portion, and wherein the lower thread interfering member pivots in accordance with the weight of the weight member.  
     
     
         10 . The lower thread supply control apparatus for a sewing machine according to  claim 8 , wherein the detection device is a non-contact type sensor, and wherein the sensor outputs the cut thread detection signal based on the fact that a predetermined light emitted from the sensor is blocked by the lower thread interfering member.  
     
     
         11 . The lower thread supply control apparatus for a sewing machine according to  claim 8 , wherein the sewing machine includes a plurality of needles arranged in a predetermined direction, a plurality of loopers, and a plurality of lower thread interfering members, the loopers and the lower thread interfering members corresponding to the needles; 
 wherein the detection device emits a predetermined light along the arrangement direction of the lower thread interfering members.    
     
     
         12 . An eccentric mechanism for a sewing machine, comprising: an eccentric shaft; an eccentric member, which is fixed to the eccentric shaft to integrally rotate with the eccentric shaft, and wherein the eccentric member includes an eccentric cylindrical portion, the eccentric cylindrical portion having a central axis displaced from a rotation axis of the eccentric shaft; and a connecting rod having a sliding ring portion and a rod portion, wherein the sliding ring portion of the connecting rod is rotatably fitted to the eccentric cylindrical portion of the eccentric member, wherein the rod portion of the connecting rod is coupled to at least one of a needle driving mechanism and a looper driving mechanism, wherein the eccentric mechanism converts rotation of the eccentric shaft into linear reciprocation of the connecting rod, 
 wherein a material of at least one of the eccentric member and the connecting rod is one of aluminum, an aluminum alloy, titanium, a titanium alloy, and ceramics.    
     
     
         13 . The eccentric mechanism for a sewing machine according to  claim 12 , wherein a hollow portion is formed in the eccentric cylindrical portion of the eccentric member.  
     
     
         14 . The eccentric mechanism for sewing machine according to  claim 12 , wherein the eccentric member has a flange portion for determining the position of the sliding ring portion of the connecting rod relative to the eccentric cylindrical portion, and wherein a spacer is located between the flange portion and the sliding ring portion.  
     
     
         15 . The eccentric mechanism for sewing machine according to  claim 14 , wherein a stopper plate is fixed to the eccentric cylindrical portion, the stopper plate being located at a side opposite from the flange portion, wherein, in a state where the sliding ring portion of the connecting rod is fitted to the eccentric cylindrical portion, the stopper plate cooperates with the flange member to determine the position of the sliding ring portion relative to the eccentric cylindrical portion, and wherein an annular spacer is located between the stopper plate and the sliding ring portion.  
     
     
         16 . A sewing machine, comprising a sewing section for sewing fabric, a feeding section that feeds fabric to the sewing section, and a winding section that sends out material sewn by the sewing section while winding the sewn material, wherein the winding section includes: 
 a drive roller having a drive pulley, the drive pulley rotating integrally with the drive roller;    a free roller rotatable about its axis, the free roller being capable of approaching and separating from the drive roller;    a free pulley rotating integrally with the free roller;    a rotation pulley rotatable about its axis, the rotation pulley being capable of approaching and separating from the drive pulley;    urging means for urging the rotation pulley away from the drive pulley; and    a timing belt for coupling the free pulley, the drive pulley, and the rotation pulley to one anther,    wherein the urging means urges the rotation pulley, thereby adjusting the spaces among the drive pulley, the free pulley, and the urging pulley by means of the timing belt, and wherein, in accordance with the space adjustment, the space between the drive roller and the free roller is adjusted.    
     
     
         17 . The sewing machine according to  claim 16 , wherein the rotation pulley and the timing belt urge the free pulley toward the drive pulley.  
     
     
         18 . The sewing machine according to  claim 16 , wherein the timing belt extends in a direction along which the sewn material is wound.  
     
     
         19 . The sewing machine according to  claim 16 , wherein the free roller is moved in a direction along which the sewn material is sent out and in the opposite direction.  
     
     
         20 . The sewing machine according to  claim 16 , wherein the drive pulley and the free pulley have the same outer diameters.  
     
     
         21 . The sewing machine according to  claim 16 , wherein the winding section includes second urging means for urging a shaft of the free pulley toward the drive pulley.  
     
     
         22 . A sewing machine, comprising: 
 a needle, wherein an upper thread is drawn through the needle, and the needle reciprocates between a top dead center above a needle plate and a bottom dead center below the needle plate;    a looper, which is located below the needle plate and corresponds to the needle, wherein, when the needle reciprocates, a blade portion of the looper, through which a lower thread is drawn, moves back and forth in a laterally adjacent area of the needle along a path intersecting the reciprocation path of the needle, thereby, together with the needle, forming predetermined stitches, in which the lower thread is interlooped with an upper thread drawn through the needle, on sewing fabric that is moving on the needle plate; and    a needle vibration limiting member located adjacent to the blade portion, wherein the space between the needle vibration limiting member and the blade portion is substantially equal to the outer diameter of the needle, wherein, when the needle reciprocated in the vicinity of the bottom dead center, the needle vibration limiting member moves back and forth in an area opposite from the blade portion, and cooperates with the blade portion to hold the needle from both sides.    
     
     
         23 . The sewing machine according to  claim 22 , wherein the needle vibration limiting member is located diagonally downward of the blade portion.  
     
     
         24 . The sewing machine according to  claim 22 , wherein the front end of the needle vibration limiting member protrudes forward of the front end of the blade portion.  
     
     
         25 . The sewing machine according to  claim 22 , wherein the needle vibration limiting member has a smooth bulge at a section facing the blade portion.  
     
     
         26 . The sewing machine according to  claim 22 , further comprising an aiding member located diagonally downward of the blade portion, wherein, when the needle starts moving from the bottom dead center to the top dead center, the aiding member contacts a loop of the upper thread formed at the needle from below in a lifting manner, thereby aiding expansion of the loop.  
     
     
         27 . The sewing machine according to  claim 22 , wherein the position of the needle vibration limiting member relative to the blade portion of the looper can be fine tuned.  
     
     
         28 . A sewing machine comprising a sewing section, wherein the sewing section includes: 
 a needle plate;    a needle, wherein the needle reciprocates between a top dead center above the needle plate and a bottom dead center below the needle plate; and    a looper located below the needle plate,    the sewing machine further comprising: 
 a thread cutting blade, wherein, below the needle plate, the thread cutting blade is moved between a cutting position, where the blade enters a space between the needle plate and the looper, and a standby position, where the blade is laterally adjacent to the looper.  
   
     
     
         29 . The sewing machine according to  claim 28 , further comprising a sliding plate at a lower side of the needle plate, wherein the sliding plate is slidable in a predetermined direction, and wherein the thread cutting blade is attached to the lower side of the sliding plate.  
     
     
         30 . The sewing machine according to  claim 28 , further comprising a device for sliding the sliding plate.  
     
     
         31 . The sewing machine according to  claim 28 , further comprising a spreader, wherein, below the needle plate, the spreader catches threads while binding the threads at a predetermined timing in relation to vertical movement of the needle, and wherein the thread cutting blade is located between the spreader and the looper.