Abstract:
A restoring device of a tension adjusting device in a transverse arm for a sewing machine includes a main part which has an active member and a passive member on two sides thereof so as to drive two sides of a pressing board of the control set. When the user adjusts the adjusting knob, the control set of the tension adjusting mechanism can be adjusted by the movement of the pressing board so as to prolong the life of use of the control set.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a restoring device of tension adjusting device for sewing machines and two ends of each control set are controlled by an active member of the main part so as to restore the tension adjusting mechanism evenly. 
   BACKGROUND OF THE INVENTION 
   A conventional tension adjusting device generally includes multiple sets of adjusting units which are required to be restored precisely. However, there are some inherent problems which are not overcome by the existed tension adjusting device. 
   The present invention intends to provide a restoring device of the tension adjusting device of sewing machines, and the restoring device includes a restoring arm and a restoring member on two sides of the main part and the two restoring arm and member apply forces on the pressing board which evenly applies to the restoring sets so as to achieve the desired functions. 
   SUMMARY OF THE INVENTION 
   The present invention relates to a restoring device of a tension adjusting device in a transverse arm for a sewing machine. The tension adjusting device comprises a main part with a plurality of tension adjusting frames, micro-adjusting sets and restoring sets connected thereto so as to form a tension adjusting mechanism. The restoring sets are controlled by a control set on the main part which has an active member which driven by an adjusting knob and the active member drives a control shaft on the main part. The control set has a pressing board which is pivotably connected to the main part so as to press and control the restoring set. The control shaft has a driving member connected thereto and the pressing board is driven by the active member and the driving member. 
   The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows the sewing machine with the restoring device of the present invention; 
       FIG. 2  shows the tension adjusting mechanism of the present invention; 
       FIG. 3  is an exploded view to show the tension adjusting mechanism of the present invention; 
       FIG. 4  shows a top view of the tension adjusting mechanism of the present invention; 
       FIG. 5  shows a right side view of the tension adjusting mechanism of the present invention; 
       FIG. 6  shows a left side view of the tension adjusting mechanism of the present invention; 
       FIG. 7  shows a top view of another embodiment of the tension adjusting mechanism of the present invention, and 
       FIG. 8  shows a top view of yet another embodiment of the tension adjusting mechanism of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 to 4 , a tension adjusting device “A” is received in a transverse arm  12  of a sewing machine  10  and the tension adjusting device “A” comprises a main part  20  with a plurality of tension adjusting frames  30 , micro-adjusting sets  40  and restoring sets  50  connected thereto so as to form a tension adjusting mechanism “B”. Each of the tension adjusting frames  30  has a micro-adjusting set  40  connected thereto. Each micro-adjusting set  40  includes a restoring set  50  which is controlled by a control set  60  on the main part  20 . The control set  60  has a restoring control part on each of the two ends thereof so as to apply a force on the pressing board  61 . 
   The main part  20  has a bracket  201  at one end thereof and two holes  202  are defined through two ends of the bracket  201 . A retainer  21  is threadedly connected to the bracket  201  such that a second control shaft  22  extends through the bracket  201  and a hole in the retainer  21 . An active member  24  is mounted to the second control shaft  22  and an end of the second control shaft  22  extends beyond the transverse arm  12  so as to be connected to a control shaft  26 . 
   Five control wheels  27  are mounted to the control shaft  26  and each have a plurality of travel control portions  270 . A passive member  25  is connected to the end of the control shaft  26  that extends through the bracket  201  by a C-shaped clip. Five pins  203  are connected to the main part  20  and a control arm  28  mounted to each of the pins  203 . The control arm  28  includes a contact end  282  at one end thereof and the other end of the control arm  28  has a pushing end  281 . The contact end  282  is located close to the tension adjusting frame  30  and the pushing end  281  is engaged with the travel control portion  270  of the control wheel  27 . 
   The tension adjusting mechanism “B” further has a threaded hole  205  and a positioning rod  206  located beside the pin  203  corresponding thereto. An active wheel  240  is connected to the active member  24  and engaged with the passive wheel  250  of the passive member  25 . The other end of the control shaft  26  extends through the main part  20  and is connected to a driving member  65 . A restoring disk  241  is connected to an outer periphery of the active member  24 . 
   The tension adjusting frame  30  has a main shaft  303 , a stop pin  304  and a micro-adjusting shaft  306  which is connected to a micro-adjusting set  40 . A tension plate  31 , a spring  32 , an end plate  34  and an adjusting gear  33  are respectively mounted to the main shaft  303 . Two holes  305  are defined through the tension adjusting frame  30  so that the restoring sets  50  can be positioned. The micro-adjusting set  40  has a micro-adjusting member  41  which is engaged with the adjusting gear  33 . The micro-adjusting member  41  has a correction member  42  at a center thereof and the correction member  42  has correction rods  422  and restoring rod  421 . The stop pin  304  keeps the tension plate  31  and the end plate  34  to be stationary. The spring  32  is biased between the end plate  34  and the tension plate  31 . 
   The restoring set  50  has a restoring active pawl  51  and a restoring passive pawl  52  which is engaged with the restoring active pawl  51 . Each of the restoring active pawl  51  and the restoring passive pawl  52  has a restoring end  512 / 522  so that the restoring set  50  may clamp the restoring rod  421 . The restoring active pawl  51  has an action end  513  which extends toward the main part  20  and is located opposite to a pressing board  61  of a control set  60 . 
   Two ends of the pressing board  61  of the control set  60  are connected to a restoring arm  62  and a pushing end  630  extending from the extension portion  63  of the control set  60 . Two respective free ends of the restoring arm  62  and the extension portion  63  are connected to the control shaft  26 . A restoring member  64  is located above the extension portion  63  which has an end in contact with an end of the restoring member  64 , the other end of the restoring member  64  has a rod  641 . The control shaft  26  has an end which extends through the main part  20  and a driving member  65  is connected to the end of the control shaft  26 . The main part  20  has an end piece  29  which is in contact with the restoring arm  62 . The restoring arm  62  has a rod  620  so as to be engaged with the driving member  65 . The passive wheel  250  is engaged with the rod  620  on the restoring arm  62  and the rod  641  on the restoring member  64 . The pressing board  61  has an adjusting hole  610  defined therethrough which is located corresponding to the action end  513  of the restoring active pawl  51  so that an adjusting bolt  611  extends through the adjusting hole  610  and contacts the action end  513 . 
   The control arm  28  includes a contact end  282  at one end thereof and the other end of the control arm  28  has a pushing end  281 , the contact end  282  is located close to the tension adjusting frame  30  and the pushing end  281  is engaged with the travel control portion  270  of the control wheel  27 . 
   As shown in  FIGS. 4 to 6 , when restoring the sewing machine  10 , it is regardless to the positions of the restoring rods  421  of the micro-adjusting sets  40 , when the adjusting knob  23  is rotated, the restoring arm  62  is driven by the rod  620  of the control set  60  which is activated by the restoring disk  241 , the restoring arm  62  applies a force on the pressing board  61 . The restoring arm  62  moves back to its initial position by the end piece  29 . The restoring disk  241  is driven by the active member  24  and the passive member  25 , and activates the driving member  65  on the other end of the control shaft  26 . The driving member  65  drives the rod  641 , the function end  640  and the pushing end  630  to apply a force to the connection boards  613 . The pressing board  61  is applied by two respective forces from the connection boards  613  at two ends of the pressing board  61  so as to evenly press the action end  513  of the restoring active pawl  51  and drives the restoring passive pawl  52  so that both of the restoring active pawl  51  and drives the restoring passive pawl  52  are pivoted and the restoring ends  512 ,  522  move toward the initial positions simultaneously. The restoring rod  421  is then pushed to its original position. When the adjusting knob  23  is adjusted to another tension scale, the restoring disk  241  slips over one tooth, the restoring rod  421  is not clamped and able to move within a range of the active pawl  51  and the passive pawl  52 . 
   As shown in  FIG. 7 , the extension portion  63 , the restoring member  64  and the driving member  65  on one side of the main part  20  in the previous drawings can also be connected to two sides of the main part  20 . Another restoring member  64  is installed to the restoring arm  62  as it was in the previous drawings such that the rod  641  is engaged with the driving member  65 . The extension portion  63  is connected to the restoring disk  241  so that one end of the extension portion  63  is in contact with the restoring member  64 , and the other end extends beyond the main part  20  and is in contact with the end piece  29 . By this arrangement, the end piece  29  provides force to restore the extension portion  63 . 
   As shown in  FIG. 8 , the restoring arms  62  can also be installed to two sides of the main part  20 , one of the restoring arms  62  is connected to the restoring member  64  as described before and the second control shaft  22  extends through two ends of the main part  20 . The active member  24  is then removed from the control shaft  26  and pivotably connected to the second control shaft  22 . The rod  620  is engaged with the restoring disk  241  of the active member  24 . 
   The present invention provides a restoring arm  62  at one end of the main part  20  and the other end of the main part  20  is connected with the extension portion  63 , restoring member  64  and driving member  65 , or the extension portion  63 , restoring member  64  and driving member  65  are connected to each of the two ends of the main part  20 , or the active wheel  24  and the restoring arm  62  are connected to the each of the two ends of the main part  20 . Either of the arrangements is able to activate two sides of the pressing board  61  and move the pressing board  61  horizontally so that the restoring force is even. 
   While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.