Sewing machine and lower dragging wheel mechanism thereof

Abstract

The utility model provides a lower tug mechanism. The lower tug mechanism comprises a rocker arm, a roller seat, a lower roller, a base and a rotating shaft, wherein the upper end of the rocker arm is hinged with an upper swing arm; the roller seat is fixedly arranged in an opening part; the lower roller is exposed out of the bottom plate, a first synchronizing wheel is arranged at one end of the roller shaft, a second synchronizing wheel is arranged at the first end of the rotating shaft, and the first synchronizing wheel and the second synchronizing wheel are connected through a synchronizing part; the second end of the rotating shaft is sequentially sleeved with a first one-way bearing and a lower swing arm from inside to outside, a sliding groove is further formed in the lower swing arm, and the lower end of the rocker arm is hinged to the sliding groove. The utility model further provides a sewing machine which comprises the lower dragging wheel mechanism. The lower towing wheel mechanism has the advantages that driving force of the lower towing wheel mechanism comes from swinging of the tooth frame base, and the lower towing wheel mechanism and the feeding teeth can move synchronously. And when being matched with a rear towing wheel mechanism for use, the cloth feeding device has stronger cloth feeding power and mistake-proofing performance.

Description

Technical Field

[0001] The utility model relates to the technical field of sewing machines, in particular to a sewing machine and a lower drag wheel mechanism thereof. Background Art

[0002] At present, the main forms of the commonly used rear drag wheels of sewing machines include electronic rear drag wheels or mechanical rear drag wheels cooperating with stainless steel sheets or driven wheels on their bottom plates to feed materials together. Their power mainly comes from the rear drag wheels, and the stainless steel sheets and driven wheels on the bottom plates do not provide power. Therefore, for some fabrics, problems such as insufficient feeding force and easy dislocation of the upper and lower fabric layers will occur. Summary of the Utility Model

[0003] The purpose of the utility model is to provide a lower drag wheel mechanism of a sewing machine to solve the problem of insufficient feeding power existing in the prior art.

[0004] The utility model provides a lower drag wheel mechanism, which is installed in a sewing machine. The sewing machine includes a fixedly arranged bottom plate, a feeding mechanism and a rotary hook arranged below the bottom plate. The feeding mechanism includes a feeding shaft rotatably arranged in the bottom plate and a tooth frame seat arranged at one end of the feeding shaft. An upper swing arm is arranged on the feeding shaft, and an opening part penetrating up and down is formed in the bottom plate; the lower drag wheel mechanism includes a roller seat installed in the opening part, a lower roller rotatably installed in the roller seat through a roller shaft, a base fixedly arranged below the bottom plate, and a lower roller transmission unit connected between the tooth frame seat and the lower roller. The lower roller protrudes from the bottom plate; the lower roller transmission unit includes a swing arm with its upper end hinged to the upper swing arm, a rotating shaft rotatably arranged in the base, a first synchronous wheel arranged at one end of the roller shaft, a second synchronous wheel arranged at the first end of the rotating shaft, a first one-way bearing and a lower swing arm sleeved on the second end of the rotating shaft in sequence from inside to outside. The first synchronous wheel and the second synchronous wheel are connected by a synchronous part. A chute is also formed on the lower swing arm, and the lower end of the swing arm is hinged to the chute; when the tooth frame seat swings in the direction consistent with the feeding direction of the sewing machine, the first one-way bearing locks, the first synchronous wheel rotates with the rotating shaft, and the lower roller rotates; when the tooth frame seat swings in the direction opposite to the feeding direction of the sewing machine, the first one-way bearing rotates freely, the rotating shaft is stationary, and the lower roller is stationary.

[0005] Preferably, the base includes an outer cover, and the lower roller transmission unit is arranged on the side of the outer cover away from the rotary hook.

[0006] Preferably, the lower idler wheel mechanism further includes a tensioning eccentric pin, which includes a first shaft section and a second shaft section that are eccentrically arranged. The first shaft section is arranged in the base, and a tensioning wheel is rotatably sleeved on the second shaft section. The tensioning wheel abuts against the outer periphery of the synchronizing member.

[0007] Preferably, a timing belt housing is further installed in the opening portion, and the timing belt housing is located directly above the first timing pulley.

[0008] Preferably, the lower idler wheel mechanism further includes an oil shield fixedly arranged below the lower roller.

[0009] Preferably, a retaining ring is provided on the rotating shaft, the lower swing arm is U-shaped, and the retaining ring is located between the two ends of the lower swing arm.

[0010] Preferably, the second one-way bearing is further provided between the rotating shaft and the base, and the second one-way bearing is sleeved on the rotating shaft.

[0011] Preferably, it further includes a nut slidably arranged in the chute, and the lower end of the rocker arm is connected to the nut through an axially located screw.

[0012] The present utility model also provides a sewing machine, including the aforementioned lower idler wheel mechanism.

[0013] The beneficial effect of the present utility model is that a lower idler wheel mechanism with feeding power is installed on the sewing machine base plate, and its driving force comes from the swing of the tooth frame base, which can move synchronously with the feed dog. When used in conjunction with the rear idler wheel mechanism, it has stronger cloth feeding power and better anti-layer misalignment performance. Description of the Drawings

[0014] Figure 1 is a perspective view of the sewing machine of the present utility model;

[0015] Figure 2 is a perspective Figure 1 (with the outer cover removed);

[0016] Figure 3 is a perspective Figure 2 ;

[0017] Figure 4 is a perspective Figure 3 ;

[0018] Figure 5 is an exploded view of the lower idler wheel mechanism of the present utility model;

[0019] Figure 6 is a partial cross-sectional view of the lower idler wheel mechanism of the present utility model.

[0020] Component Label Explanation:

[0021] 11 Base Plate

[0022] 12 Cabinet

[0023] 13 Lifting Shaft

[0024] 131 Lifting Fork Crank

[0025] 132 Lifting Slide Block

[0026] 14 Feeding Shaft

[0027] 141 Tooth Rest

[0028] 142 Upper Swing Arm

[0029] 15 Tooth Rest

[0030] 151 Feeding Tooth

[0031] 16 Needle Plate

[0032] 2 Synchronous Belt Cover

[0033] 3 Lower Roller

[0034] 31 Roller Shaft

[0035] 32 Deep Groove Ball Bearing

[0036] 33 Annular Groove

[0037] 4 Roller Seat

[0038] 41 Anti-Jamming Rod

[0039] 42 Anti-Oil Cover

[0040] 5 Lower Roller Drive Unit

[0041] 50 Synchronous Component

[0042] 51 First Synchronous Pulley

[0043] 52 Second Synchronous Pulley

[0044] 531 First Deep Groove Ball Bearing

[0045] 532 Second Deep Groove Ball Bearing

[0046] 541 First One-Way Bearing

[0047] 542 Second One-Way Bearing

[0048] 55 Rotating Shaft

[0049] 56 Retaining Ring

[0050] 57 Third deep groove ball bearing

[0051] 58 Lower swing arm

[0052] 581 Slide groove

[0053] 59 Rocker arm

[0054] 510 Nut

[0055] 511 Axial position screw

[0056] 61 Tensioning eccentric pin

[0057] 62 Tensioning pulley

[0058] 7 Base

[0059] 71 Outer cover Detailed implementation manners

[0060] The following further elaborates in detail the detailed implementation manners of the present utility model in conjunction with the accompanying drawings. These implementation manners are only used to illustrate the present utility model and are not intended to limit the present utility model.

[0061] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0062] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0063] Figure 1 The following shows a perspective view of the sewing machine of the present utility model. In the following description, Figure 1 the accompanying drawings in Figure 1In this case, the length direction of the bottom plate 11 is defined as the left - right direction, and the needle plate 16 is located on the left side of the bottom plate 11; the width direction of the bottom plate 11 is defined as the front - back direction, and the lower roller 3 is located on the front side of the needle plate 16; the height direction of the bottom plate 11 is defined as the up - down direction, and the machine housing 12 is located above the bottom plate 11.

[0064] The utility model provides a sewing machine and its lower drag wheel mechanism.

[0065] As Figures 1-4 shown, the sewing machine includes a fixedly arranged bottom plate 11, a machine housing 12 arranged above the bottom plate 11, a needle plate 16 fixedly arranged on the upper surface of the left side of the bottom plate 11, a rotary hook (not shown) arranged below the bottom plate 11, a feeding mechanism, and a tooth - lifting mechanism. The feeding mechanism includes a feeding shaft 14 rotatably arranged in the bottom plate 11 and a tooth - frame seat 141 arranged at the left end of the feeding shaft 14. The tooth - frame seat 141 is hinged to the front end of the tooth frame 15. The tooth - lifting mechanism includes a tooth - lifting shaft 13 rotatably arranged in the bottom plate 11, a tooth - lifting fork - shaped crank 131 fixed to the left end of the tooth - lifting shaft 13, and a tooth - lifting slider 132 slidably assembled in the opening of the tooth - lifting fork - shaped crank 131. The tooth - lifting slider 132 is hinged to the rear end of the tooth frame 15. A feeding tooth 151 is fixed on the tooth frame 15, and the feeding tooth 151 can be exposed from the needle plate 16. When the sewing machine works, the feeding shaft 14 and the tooth - lifting shaft 13 are driven to rotate by the main shaft of the sewing machine or an independent motor. The feeding mechanism drives the tooth frame 15 and the feeding tooth 151 to perform a reciprocating motion in the front - back direction, and the tooth - lifting mechanism drives the tooth frame 15 and the feeding tooth 151 to perform a reciprocating motion in the up - down direction. Finally, the feeding tooth 151 performs a compound motion with an elliptical motion trajectory, driving the fabric to move forward to complete the feeding action. The rotary hook is located below the needle plate 16. Cooperating with the feeding action, the tip of the shuttle of the rotary hook hooks and enlarges the thread loop, guiding the thread loop to form a lock - stitch on the fabric.

[0066] The sewing machine further includes Figure 1 a rear drag wheel mechanism not shown in the figure. The rear drag wheel mechanism includes a rear drag wheel driving source and an upper roller driven to rotate by the rear drag wheel driving source. The upper roller is arranged above the bottom plate 11. An opening penetrating up and down is formed in the bottom plate 11.

[0067] The lower drag wheel mechanism involved in the present utility model includes a base 7 fixedly arranged below a base plate 11, a roller seat 4 detachably installed in an opening, a lower roller 3 rotatably installed in the roller seat 4 through a roller shaft 31, and a lower roller transmission unit 5 connected between the lower roller 3 and a bracket seat 141. The lower roller 3 protrudes from the base plate 11, and the protruding part thereof can be in contact with the fabric placed on the base plate 11. Meanwhile, the lower roller 3 is arranged directly below the upper roller, that is, the lower roller 3 and the upper roller are arranged vertically opposite to each other, and the fabric passes between the upper roller and the lower roller. When the sewing machine is working, the rear drag wheel driving source drives the upper roller to rotate, and the bracket seat 141 drives the lower roller 3 to rotate through the lower roller transmission unit 5. The lower roller 3 has a driving force to drive the fabric to move, and together with the upper roller and the feed dog 151, drives the fabric on the base plate 11 to move forward. Therefore, the lower drag wheel mechanism provided by the present utility model can provide sufficient feeding power, is suitable for moving thick materials, and can also avoid the problem of misalignment of the upper and lower fabrics caused by insufficient feeding power. This lower drag wheel mechanism works together with the rear drag wheel mechanism, having advantages such as strong feeding ability and good anti-layer misalignment performance. In addition, the driving force of the lower roller 3 comes from the front and rear swing of the bracket seat 141, without the need to additionally set a power source, which helps to simplify the overall structure of the lower drag wheel mechanism and reduce the production cost.

[0068] As Figures 2-6 shown, an upper swing arm 142 is provided on the above-mentioned feed shaft 14. The lower roller transmission unit 5 includes a rocker arm 59 whose upper end is hinged to the upper swing arm 142 through an axially positioned screw, a rotating shaft 55 rotatably arranged in the base 7, a first synchronous pulley 51 arranged at the left end of the roller shaft 31, a second synchronous pulley 52 arranged at the left end (i.e., the first end) of the rotating shaft 55, a first one-way bearing 541 and a lower swing arm 58 sleeved on the right end (i.e., the second end) of the rotating shaft 55 in sequence from inside to outside. The first synchronous pulley 51 and the second synchronous pulley 52 are connected by a synchronous member 50. A chute 581 is also opened on the lower swing arm 58, and the chute 581 is hinged to the lower end of the rocker arm 59. When the bracket seat 141 swings forward in the direction consistent with the sewing machine feeding direction, the first one-way bearing 541 locks, and the first one-way bearing 541 makes the second synchronous pulley 52 and the first synchronous pulley 51 rotate with the rotating shaft 55, the roller shaft 31 rotates, and the lower roller 3 rotates accordingly; when the bracket seat 141 swings backward in the direction opposite to the sewing machine feeding direction, the first one-way bearing 541 rotates freely, and the first one-way bearing 541 makes the rotating shaft 55 stationary, and the lower roller 3 is stationary.

[0069] The specific form of the synchronous member 50 is not limited, and can be a belt or a chain, and the first synchronous wheel 51 and the second synchronous wheel 52 are correspondingly pulleys or sprockets. The roller shaft 31 extends in the left-right direction, and the left and right ends of the roller shaft 31 are rotatably arranged in the roller seat 4 through a deep groove ball bearing 32. The rotating shaft 55 extends in the left-right direction, between the second synchronous wheel 52 and the lower swing arm 58, and the rotating shaft 55 is sequentially sleeved with a first deep groove ball bearing 531, a second one-way bearing 542 and a second deep groove ball bearing 532 from left to right, and all three are located between the rotating shaft 55 and the base 7. Further, the lower swing arm 58 is U-shaped, including a left end and a right end. The first one-way bearing 541 is arranged between the left end of the lower swing arm 58 and the rotating shaft 55, and a third deep groove ball bearing 57 is also arranged between the right end of the lower swing arm 58 and the rotating shaft 55. A retaining ring 56 is also provided at the right end of the rotating shaft 55. The retaining ring 56 is located between the two ends of the lower swing arm 58 and is used to limit the left and right movement of the lower swing arm 58. A nut 510 is slidably provided in the slide groove 581 of the lower swing arm 58. The lower end of the rocker arm 59 is fastened to the nut 510 by an axial screw 511. The lower end of the rocker arm 59 is hinged to the axial screw 511.

[0070] Furthermore, a synchronous belt cover 2 is installed in the opening, and the synchronous belt cover 2 is located directly above the first synchronous wheel 51 and is arranged adjacent to the roller seat 4. The synchronous belt cover 2 covers the first synchronous wheel 51 and the top of the synchronous member 50, and the roller seat 4 only allows the lower roller 3 to be exposed. The two work together to prevent dust and wool from entering the inside or below the bottom plate 11 from the opening. Furthermore, a plurality of anti-cloth rods 41 are arranged at intervals along the left and right directions on the roller seat 4, and an annular groove 33 having the same number as the anti-cloth rods 41 is arranged on the lower roller 3. Each anti-cloth rod 41 is arranged across the annular groove 33. The anti-cloth rod 41 can prevent the fabric from being rolled into the roller seat 4 as the lower roller 3 rotates, and it will not hinder the contact between the roller surface 33 and the fabric.

[0071] like Figures 2-3 and Figure 5 As shown, the lower tug mechanism also includes a tensioning eccentric pin 61, which includes an eccentrically arranged first shaft section and a second shaft section. The first shaft section is arranged in the base 7, and a tensioning wheel 62 is rotatably sleeved on the second shaft section. The tensioning wheel 62 abuts against the outer periphery of the synchronous member 50. By rotating the first shaft section, the tensioning wheel 62 on the second shaft section can be driven to approach or move away from the synchronous member 50, thereby adjusting the tension of the synchronous member 50 to avoid the synchronous member 50 being too tight or too loose, and reducing the operating noise. Preferably, the tensioning wheel 62 can adopt a needle bearing. Figure 4 As shown, the lower tug mechanism also includes an oil-proof cover 42 fixedly arranged below the lower roller 3. The oil-proof cover 42 can be used to receive dripping lubricating oil and impurities.

[0072] In summary, the working principle of the lower drag wheel mechanism provided by the present utility model is as follows: When the sewing machine is working, the feed shaft 14 drives the bracket seat 141 to swing back and forth. With the cooperation of the lifting tooth mechanism, the feed tooth 151 drives the fabric to move forward. At the same time, the swinging bracket seat 141 drives the rotating shaft 55 to rotate intermittently. When the bracket seat 141 swings forward in the direction consistent with the sewing machine's feeding direction, the lower swing arm 58 swings downward, and the first one-way bearing 541 locks. The first one-way bearing 541 causes the second synchronous wheel 52 and the first synchronous wheel 51 to rotate with the rotating shaft 55, the roller shaft 31 rotates, and the lower roller 3 rotates accordingly to assist in feeding. When the bracket seat 141 swings backward in the direction opposite to the sewing machine's feeding direction, the lower swing arm 58 swings upward, the first one-way bearing 541 rotates freely, and the first one-way bearing 541 causes the rotating shaft 55 to be stationary and the lower roller 3 to be stationary.

[0073] Further, as Figure 2 and Figure 3 shown, the base 7 includes an outer cover 71 arranged in the up and down direction. The outer cover 71 covers the rear side of the second synchronous wheel 52 and the synchronizing member 50. The lower roller transmission unit 5 is located on the side of the outer cover 71 away from the rotary hook, that is, the front side. Such a setting can keep the lower roller transmission unit 5 away from the rotary hook, avoiding interference with the operation of replacing the bobbin core of the rotary hook. At the same time, it also helps to make the structure of the lower roller transmission unit 5 more compact and save installation space.

[0074] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the technical principle of the present utility model, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present utility model.

Claims

1. A lower tug mechanism installed in a sewing machine, the sewing machine comprising a fixed bottom plate, a feeding mechanism and a rotary hook arranged below the bottom plate, the feeding mechanism comprising a feeding shaft rotatably arranged in the bottom plate and a tooth frame seat arranged at one end of the feeding shaft, characterized in that: The feeding shaft is provided with an upper swing arm, and the bottom plate is provided with an opening that passes through from top to bottom; The lower tug mechanism comprises a roller seat installed in the opening, a lower roller rotatably installed in the roller seat through a roller shaft, a base fixedly arranged below the bottom plate, and a lower roller transmission unit connected between the tooth frame seat and the lower roller, wherein the lower roller is exposed from the bottom plate; The lower roller transmission unit comprises a rocker arm whose upper end is hinged to the upper rocker arm, a rotating shaft rotatably arranged in the base, a first synchronous wheel arranged at one end of the roller shaft, a second synchronous wheel arranged at the first end of the rotating shaft, and a first one-way bearing and a lower rocker arm which are sequentially sleeved on the second end of the rotating shaft from inside to outside, the first synchronous wheel and the second synchronous wheel are connected by a synchronous member, a slide groove is also provided on the lower rocker arm, and the lower end of the rocker arm is hinged to the slide groove; When the tooth frame seat swings in a direction consistent with the feeding direction of the sewing machine, the first one-way bearing is locked, the first synchronous wheel rotates with the rotating shaft, and the lower roller rotates; When the tooth frame seat swings in the direction opposite to the feeding direction of the sewing machine, the first one-way bearing rotates freely, the rotating shaft is stationary, and the lower roller is stationary.

2. The lower tug mechanism according to claim 1, characterized in that: The base comprises an outer cover, and the lower roller transmission unit is arranged on a side of the outer cover away from the rotary shuttle.

3. The lower tug mechanism according to claim 1, characterized in that: The lower tug mechanism also includes a tensioning eccentric pin, which includes an eccentrically arranged first shaft segment and a second shaft segment, wherein the first shaft segment is arranged in the base, and a tensioning wheel is rotatably sleeved on the second shaft segment, and the tensioning wheel abuts against the outer periphery of the synchronizer.

4. The lower tug mechanism according to claim 1, characterized in that: A synchronous belt cover is also installed in the opening portion, and the synchronous belt cover is located directly above the first synchronous wheel.

5. The lower tug mechanism according to claim 1, characterized in that: The lower tug mechanism also includes an oil-proof cover fixedly arranged below the lower roller.

6. The lower tug mechanism according to claim 1, characterized in that: A retaining ring is arranged on the rotating shaft, the lower swing arm is U-shaped, and the retaining ring is located between the two ends of the lower swing arm.

7. The lower tug mechanism according to claim 1, characterized in that: A second one-way bearing is also provided between the rotating shaft and the base, and the second one-way bearing is sleeved on the rotating shaft.

8. The lower tug mechanism according to claim 1, characterized in that: It also includes a nut slidably arranged in the slide groove, and the lower end of the rocker arm is connected to the nut through an axial screw.

9. A sewing machine, characterized in that: It comprises a lower tug mechanism as claimed in any one of claims 1 to 8.

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