Patent Publication Number: US-2022220650-A1

Title: Rotary shuttle for sewing machine

Description:
FIELD OF INVENTION 
     The present invention relates to a rotary shuttle for a sewing machine, and more particularly to a rotary shuttle for a sewing machine including a lower thread outlet channel formed in a bobbin case to easily mount a lower thread unwound from the center, and thus a manager of a mass-operated sewing machine easily manages the sewing machine. 
     BACKGROUND OF INVENTION 
     In general, a rotary shuttle includes an outer bobbin case, an inner bobbin case rotating while accommodated on the outer bobbin case, and a bobbin case. The outer bobbin case rotates while being coupled to a rotation shaft, and the inner bobbin case is rotatably installed with respect to the outer bobbin case. 
     The bobbin case is detachably mounted to cover a front part of the inner bobbin case, and a bobbin with a lower thread wound therearound is accommodated in the bobbin case or a lower thread wound in the form of a cylinder is directly accommodated in the bobbin case, and the bobbin case is mounted on the inner bobbin case of a sewing machine. In general, rotation of the inner bobbin case is regulated by a bobbin stopper installed on a needle plate. 
     In this regard, the conventional technology is disclosed in Korean Patent Publication No. 10-1010835 (registered on Jan. 18, 2011) of “Rotary shuttle of sewing machine”. 
     The conventional technology discloses a rotary shuttle  10  for a sewing machine, including an outer bobbin case that rotates in one direction from the bottom of a needle plate  5  installed on a bed  1  and has a hook tip extending in a rotation direction on a portion of an outer circumference, and an inner bobbin case that is relatively and rotatably installed on a front part of the outer bobbin case, and a bobbin case, and in this case, an inclined surface for thread sliding inclined toward a front surface of the bobbin case is formed on the outer circumference of the outer bobbin case that is continuously formed on a base of the hook tip, and an upper thread loop held by the hook tip slides along the inclined surface for thread sliding to pass through the front surface of the bobbin case by rotation of the outer bobbin case. 
     A radius of a portion of the outer bobbin case, on which the inclined surface for thread sliding is formed, is greater than a radius of a portion of the outer bobbin case, which faces the portion of the outer bobbin case, on which the inclined surface for thread sliding is formed, based on a rotation shaft of the outer bobbin case. 
     An inclined surface for thread movement inclined in the same direction as the inclined surface for thread sliding is installed on a part of the inclined surface for thread sliding, which is opposite to the hook tip. 
     An inclination angle of the inclined surface for thread movement based on the rotation shaft of the outer bobbin case is greater than an inclination angle of the inclined surface for thread sliding based on the rotation shaft. 
     However, conventionally, a separate mounting shaft on which the bobbin case is mounted is provided inside the inner bobbin case, and accordingly, the amount of the lower thread wound on the bobbin is reduced as compared to the lower thread wound without the bobbin, and there is a problem in that the lower thread needs to be frequently replaced in a mass-operated sewing machine. 
     Conventionally, it is difficult to unwind the lower thread from the bobbin and to pull out the thread to an upper part of the needle plate  5 , and thus, there is a problem in that it takes a lot of time to replace the lower thread. 
     SUMMARY OF INVENTION 
     Technical Problem to be Solved 
     Therefore, the present invention has been made in view of the above problems, and it is one object of the present invention to provide a rotary shuttle for a sewing machine including a lower thread outlet hole and an outlet channel that are formed in a lower thread case to easily pull out a lower thread pulled out from the center after the lower thread is mounted on the lower thread case, and a lower thread hanger bent inward at an end of a bobbin shell, thereby easily managing the lower thread that is mass-replaced. 
     Technical Solution 
     In accordance with one aspect of the present invention, provided is a rotary shuttle for a sewing machine including a hook body having a lower part to which a drive shaft is rotatably coupled, a lower thread base that is coupled to an inner circumference of the hook body to rotate in a direction opposite to the hook body when the drive shaft rotates and includes a concave groove recessed in a downward direction on an upper part of a main wall, and a lower thread case surrounding upper and lateral parts of a lower thread that is inserted into the lower thread base to expose an upper part thereof. 
     The lower thread case may include a protrusion that protrudes to be inserted into the concave groove by spring elastic force, a hook having one end coupled to a hook coupling hole formed in the protrusion and moving the protrusion in an inward direction when a remaining end is lifted, a case body that includes a protrusion inlet formed on an upper part thereof to allow opposite lateral parts of the protrusion to be inserted thereinto and to be supported by spring elastic force and is shaped like a cylinder with an opened lower surface to insert the lower thread thereinto, and a bobbin shell coupled to one side of an outer circumference of the case body and including a lower thread hanger bent inward at one end to guide the lower thread when the lower thread is pulled out. 
     The protrusion inlet may include a lower thread concave groove formed in one end thereof to be positioned inward to guide the lower thread when the lower thread is pulled out. 
     The lower thread case may include a lower thread outlet hole formed through centers of the case body, the protrusion, and the hook to easily pull out the lower thread, and an outlet hole channel formed on the protrusion and the case body to connect the lower thread outlet hole to an outer lateral part thereof. 
     The bobbin shell may include a case fixing unit that extends from the lower thread hanger and is coupled to the outer circumference of the case body, and an elastic insert unit that extends from the case fixing unit and is in close contact with an outer circumference of the lower thread case by elastic force, and the elastic insert unit includes a lower thread separation prevention end that is bent inward to prevent separation of the lower thread. 
     The lower thread separation prevention end may include an upper prevention end bent from an upper part thereof and a lower prevention end bent from a lower part thereof to pull out the lower thread from a center of an end thereof, and the case body may include a prevention end concave groove through which the lower thread separation prevention end is positioned inward. 
     A lower thread hanger that rotates spirally and extends to position the lower thread at a center thereof and to pull out the lower thread from the center may be provided at one side of an upper surface of the case body. 
     Effect of Invention 
     The rotary shuttle for a sewing machine according to the present invention may have the following effects. 
     First, a lower thread outlet hole formed through the centers of a protrusion and a hook to pull out a lower thread and an outlet channel may be formed in a case body forming a lower thread case, and thus the lower thread pulled out from the center may be easily pulled out. 
     Second, a lower thread concave groove may be formed in a protrusion inlet to accommodate the lower thread pulled out through the outlet channel, and thus the lower thread may be easily guided when the lower thread is pulled out, thereby preventing the lower thread from becoming entangled. 
     Third, a lower thread hanger bent inward may be provided at one end of the bobbin shell, and a lower thread separation prevention end may be provided at the other end, and thus the lower thread pulled out through the lower thread concave groove may be easily pulled out from an upper plate of the sewing machine. 
     Fourth, a lower thread hanger shaped like a pig tail may be provided on a case body forming the lower thread case, and accordingly, tension of the lower thread may be maintained constant, and malfunction may be prevented, thereby stably pulling out the lower thread. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram for explaining a conventional rotary shuttle for a sewing machine. 
         FIG. 2  is an exploded perspective view of a rotary shuttle for a sewing machine according to the present invention. 
         FIG. 3  is a diagram for explaining a bobbin shell according to the present invention. 
         FIG. 4  is a diagram showing a plane and side of a lower thread case according to the present invention. 
         FIG. 5  is a diagram for explaining a state in which a lower thread is pulled out from a lower thread case according to the present invention. 
     
    
    
     BEST MODE 
     Hereinafter, a rotary shuttle for a sewing machine according to the present invention will be described in detail with reference to the accompanying drawings. 
     As shown in  FIGS. 2 to 5 , the rotary shuttle for a sewing machine according to the present invention includes a hook body  10  having a lower part to which a drive shaft is rotatably coupled, a lower thread base  20  that is coupled to an inner circumference of the hook body  10  to rotate in a direction opposite to the hook body  10  when the drive shaft rotates and includes a concave groove  21  recessed in a downward direction on an upper part of a main wall, and a lower thread case  30  surrounding upper and lateral parts of a lower thread A that is inserted into the lower thread base  20  to expose an upper part thereof and is drawn out from the center thereof. 
     That is, the lower thread A may be drawn out from the center, and a larger amount of the lower thread A may be wound than in the case in which a separate bobbin is used. 
     The lower thread case  30  may include a protrusion  31  that protrudes to be inserted into the concave groove  21  by spring elastic force, a hook  32  having one end coupled to a hook coupling hole  31   a  formed in the protrusion  31  and moving the protrusion  31  in an inward direction when the other end is lifted, a case body  33  that includes a protrusion inlet  33   a  formed on an upper part thereof to allow opposite lateral parts of the protrusion  31  to be inserted thereinto and to be supported by spring elastic force and is shaped like a cylinder with an opened lower surface to insert the lower thread A thereinto, and a bobbin shell  34  coupled to one side of an outer circumference of the case body  33  and including a lower thread hanger  34   a  bent inward at one end to guide the lower thread A when the lower thread A is pulled out. 
     When the hook  32  is lifted, the protrusion  31  may be positioned inward and may be inserted into the concave groove  21 , and when the hook  32  is released, the protrusion  31  may protrudes outward by spring elastic force and may be caught on an inner end of the upper part of the concave groove  21 . 
     The protrusion inlet  33   a  may include a lower thread concave groove  33   a ′ formed in one end thereof to be positioned inward to guide the lower thread A when the lower thread A is pulled out, and thus the lower thread A may be stably pulled out through an upper part of the case body  33 . 
     The lower thread case  30  may include a lower thread outlet hole  30   a  formed through the centers of the case body  33 , the protrusion  31 , and the hook  32  to easily pull out the lower thread A, and an outlet hole channel  30   b  formed on the protrusion  31  and the case body  33  to connect the lower thread outlet hole  30   a  to an outer lateral part thereof, and thus the lower thread A may be positioned inside the lower thread concave groove  33   a ′ and may be pulled out through a lower part of the hook  32 . 
     The bobbin shell  34  may include a case fixing unit  34   b  that extends from the lower thread hanger  34   a  and is coupled to the outer circumference of the case body  33 , and an elastic insert unit  34   c  that extends from the case fixing unit  34   b  and is in close contact with an outer circumference of the lower thread case  30  by elastic force, and the elastic insert unit  34   c  may include a lower thread separation prevention end  341  that is bent inward to prevent separation of the lower thread A. The lower thread A may be pulled out while being positioned between the bobbin shell  34  and the case body  33  by lifting the lower thread separation prevention end  341  of the bobbin shell  34 . 
     Here, the lower thread separation prevention end  341  may include an upper prevention end  341 ′ bent from an upper part thereof and a lower prevention end  341 ″ bent from a lower part thereof to pull out the lower thread A from the center of an end thereof, and the case body  33  may include a prevention end concave groove  33   c  through which the lower thread separation prevention end  341  is positioned inward, and accordingly, the lower thread A may be pulled out through a space between the upper prevention end  341 ′ and the lower prevention end  341 ″. 
     A lower thread hanger  33   b  that rotates spirally and extends to position the lower thread A at the center thereof and to pull out the lower thread A from the center may be provided at one side of an upper surface of the case body  33 , and accordingly, even if the hook body  10  rotates rapidly, the upper thread and the lower thread A may be prevented from becoming entangled. 
     An operation of the rotary shuttle for a sewing machine according to the present invention as configured above will be described below. 
     As shown in  FIGS. 2 to 5 , the rotary shuttle for a sewing machine according to the present invention may be accommodated in the lower thread case  30  inserted into the lower thread base  20  to supply the lower thread A from the center while being wound without a bobbin. The lower thread base  20  may be accommodated inside the hook body  10  to rotate in a direction opposite to the hook body  10 . 
     The lower thread A may be wound more using a space between a central axis and upper and lower plates of a bobbin (not shown) as a winding space than in the case in which a bobbin is used, and accordingly, maintenance costs may be reduced when a mass-operated sewing machine is used. 
     The lower thread outlet hole  30   a  may be formed through the center of an upper surface of the lower thread case  30 , and the outlet hole channel  30   b  may be cut to connect the lower thread outlet hole  30   a  to the lateral part, and thus the lower thread A may be easily pulled out. 
     That is, the lower thread A pulled out from the center may be positioned between a lower surface of the hook  32  and an upper surface of the protrusion  31  and may be pulled out from the lateral part through the lower thread outlet hole  30   a  and the outlet hole channel  30   b . The lower thread A may be pulled out from the bobbin shell  34  through the lower thread concave groove  33   a ′ of the protrusion inlet  33   a.    
     The bobbin shell  34  may be bolted to the outer circumference of the lateral part of the case body  33  through the case fixing unit  34   b , and the lower thread A may be pulled out from the upper part through the lower thread hanger  34   a  and the elastic insert unit  34   c . In this case, the lower thread separation prevention end  341  bent inward may be provided at an end of the elastic insert unit  34   c , thereby preventing separation of the lower thread A. 
     The lower thread A positioned between the bobbin shell  34  and the case body  33  may be pulled out from an upper plate of the sewing machine through the lower thread hanger  33   b  having a spiral shape to maintain tension when being pulled out from the upper plate through the lower thread separation prevention end  341 , and thus may be completely mounted. 
     As such, the rotary shuttle according to the present invention may be rapidly mounted through the lower thread outlet hole  30   a , the outlet hole channel  30   b , the lower thread concave groove  33   a ′, the lower thread hanger  34   a , the lower thread separation prevention end  341 , and the lower thread hanger  33   b  in order to easily mount the lower thread A supplied from the center, and accordingly, when the rotary shuttle is applied to a large-scale sewing machine, the sewing machine may be efficiently managed with limited manpower and productivity may be improved. 
     It is clearly understood that the same is by way of illustration and example only and is not to be taken as limiting the present invention, and it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the subject matter and scope of the present invention. 
     EXPLANATION OF REFERENCE NUMERALS 
     
         
         
           
               10 : hook body 
               20 : lower thread base 
               21 : concave groove 
               30 : lower thread case 
               30   a : lower thread outlet hole 
               30   b : outlet hole channel 
               31 : protrusion 
               31   a : hook coupling hole 
               32 : hook 
               33 : case body 
               33   a : protrusion inlet 
               33   a ′: lower thread concave groove 
               33   b : lower thread hanger 
               33   c : prevention end concave groove 
               34 : bobbin shell 
               34   a : lower thread hanger 
               34   b : case fixing unit 
               34   c : elastic insert unit 
               341 : lower thread separation prevention end 
               341 ′: upper prevention end 
               341 ″: lower prevention end 
             A: lower thread