Transmission mechanism of lockstitch sewing machine

Abstract

The utility model provides a transmission mechanism of a lockstitch sewing machine, and belongs to the technical field of machinery. The problem that an existing lockstitch sewing machine is complex in transmission structure is solved. According to the transmission mechanism of the lockstitch sewing machine, the lockstitch sewing machine comprises a rack, a main shaft, an upper feeding shaft used for being connected with a presser foot assembly and a lower feeding shaft used for being connected with a cloth feeding assembly are arranged on the rack, the main shaft is sleeved with an eccentric wheel, and the transmission mechanism comprises a swing arm connected with the upper feeding shaft and the lower feeding shaft and a connecting rod with one end arranged outside the eccentric wheel in a sleeving mode. The crank set is connected with the connecting rod and the swing arm and drives the swing arm to swing when the eccentric wheel rotates, and the swing arm is provided with a reinforcing structure for improving the strength of the swing arm. The lockstitch sewing machine has the advantages that the transmission structure is simplified, and meanwhile up-down synchronous feeding of the sewing machine is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing machines and relates to a transmission mechanism of a lockstitch sewing machine. Background Art

[0002] A lockstitch sewing machine is a machine that uses a sewing thread to form a stitch on the sewing material, so that one or more layers of sewing materials are interwoven or sewn together. It includes a feeding mechanism, a presser foot lifting mechanism, and a stitch length adjustment mechanism. The movement of the mechanism is driven by a motor, and one motor can only control one mechanism, such as the presser foot lifting mechanism or the stitch length adjustment mechanism. If two functions are to be controlled at the same time, two motors are required, resulting in high cost of the sewing machine.

[0003] Chinese patent literature discloses a composite adjustment mechanism and a sewing machine using the same CN201920556091.5, which includes a power source and an adjustment shaft, wherein the power source is connected to the adjustment shaft, and the adjustment shaft automatically starts from the power source end and is arranged along the extension direction of the adjustment shaft in sequence with a stitch adjustment crank, a drive crank, and a presser foot lifting crank, the stitch adjustment crank and the presser foot lifting crank being rotatable relative to the adjustment shaft, the stitch adjustment crank being connected to a swing seat of a feeding mechanism, the presser foot lifting crank being connected to a presser lifting connecting rod of the presser foot lifting mechanism, and the electronic control element being connected to the drive crank.

[0004] In the above-mentioned documents, the feeding mechanism and the presser foot lifting mechanism are both driven by a driving source. Specifically, the driving force output by the power source transmits the power to the stitch adjustment crank and the presser foot lifting crank via the adjustment shaft, thereby driving the presser foot lifting mechanism and the feeding mechanism to move synchronously, so that the presser foot lifting mechanism and the feeding mechanism cooperate, thereby realizing synchronous feeding of the sewing machine up and down. The adjustment crank is provided with a transmission mechanism to drive the feeding mechanism to move, and the presser foot lifting crank is also provided with a transmission mechanism to drive the presser foot lifting mechanism to move. The multiple transmission mechanisms make the structure of the sewing machine complicated. Summary of the invention

[0005] The utility model aims at the above problems existing in the prior art, proposes a transmission mechanism for a lockstitch sewing machine, and solves the technical problem of how to simplify the transmission structure while ensuring synchronous feeding of the sewing machine up and down.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] A transmission mechanism of a flat-bed sewing machine, the flat-bed sewing machine includes a frame, the frame is provided with a main shaft, an upper feed shaft for connecting a presser foot assembly, and a lower feed shaft for connecting a cloth feed assembly, and the characteristic is that an eccentric wheel is sleeved on the main shaft, the transmission mechanism includes a swing arm connecting the upper feed shaft and the lower feed shaft, and a connecting rod with one end sleeved outside the eccentric wheel, the other end of the connecting rod is provided with a crank group connecting the connecting rod and the swing arm and driving the swing arm to swing when the eccentric wheel rotates, and the swing arm has a reinforcing structure for improving its own strength.

[0008] In the prior art, the main shaft is driven to rotate by a motor. In the present application, an eccentric wheel is sleeved on the main shaft, one end of a connecting rod is sleeved outside the eccentric wheel, and the other end of the connecting rod is connected to a crank set. This structure enables the eccentric wheel to convert the rotational motion of the main shaft into an up and down reciprocating motion of the connecting rod and transmit it to the crank set, and then the crank set drives the swing arm to swing. Since the swing arm is connected to the upper feed shaft and the lower feed shaft, when the swing arm swings, the upper feed shaft and the lower feed shaft swing synchronously with the swing arm, so that the presser foot assembly connected to the upper feed shaft and the cloth feed assembly connected to the lower feed shaft move synchronously, and the amplitude of the movement is consistent, thereby ensuring that the sewing machine feeds synchronously up and down, and the presser foot assembly and the cloth feed assembly share a set of transmission structure, which simplifies the transmission mechanism of the flat-bed sewing machine. Furthermore, the present application cancels the structural setting of one motor controlling one mechanism, and instead converts the driving force of the motor that drives the main shaft to rotate into the feeding action of the presser foot assembly and the cloth feeding assembly through a transmission structure, thereby reducing manufacturing costs; on the basis of the above structure, by setting a reinforcing structure on the swing arm to improve its own strength, when the swing arm drives the upper feed shaft and the lower feed shaft to move synchronously, the swing stability of the swing arm is good, thereby improving the power transmission stability of the transmission mechanism.

[0009] In the transmission mechanism of the above-mentioned lockstitch sewing machine, the swing arm is in the shape of a long strip, one end of the swing arm is connected to the upper feed shaft, and the other end is connected to the lower feed shaft, and the reinforcement structure includes a plurality of reinforcing ribs fixedly connected to the inside of the swing arm, and the reinforcing ribs divide the inside of the swing arm into four reinforcement areas along the length direction of the swing arm. By reasonably arranging the reinforcing ribs inside the swing arm, the swing arm is divided into four reinforcement areas along its own length direction, so that the strength of the swing arm along its own length direction is improved.

[0010] In the transmission mechanism of the above-mentioned flat-bed sewing machine, the swing arm has a first side rod and a second side rod connected at the ends, a gap is formed between the first side rod and the second side rod, and the reinforcing ribs connect the first side rod and the second side rod to divide the gap into the above-mentioned four reinforcing areas. The reinforcing area is equivalent to the hollow area inside the swing arm, the hollow setting reduces the deadweight of the swing arm to a certain extent, and the reinforcing ribs ensure that the swing arm has good rigidity, that is, the structure improves the connection stability of the first side rod and the second side rod, so that the first side rod and the second side rod are not easy to bend, and avoids the situation that the swing arm has inconsistent up and down swing amplitudes due to deformation when the transmission force received by the swing arm is large, so as to ensure the consistency of up and down feeding of the flat-bed sewing machine.

[0011] In the transmission mechanism of the above-mentioned flat sewing machine, a plurality of the reinforcing ribs are arranged along the length direction of the first side rod and intersect at the second side rod, and the reinforcing areas are all triangular. The hollow area is triangular in shape, so that the swing arm has a lighter weight while ensuring the rigidity. When the swing arm transmits power, the structure allows the force of the swing arm to be dispersed along different reinforcing ribs, avoiding local stress concentration when the swing arm is subjected to force. At the same time, the structure of the reinforcing ribs arranged in a triangular shape further improves the self-strength of the swing arm.

[0012] In the transmission mechanism of the above-mentioned flat sewing machine, the number of the reinforcing ribs is three, and the second side rod is provided with a mounting hole for connecting the crank set at the intersection of the three reinforcing ribs. The intersection of the three reinforcing ribs has high strength and is not easily broken by stress. When power is transmitted, the power transmitted by the crank set is dispersed along the length direction of the swing arm through all the reinforcing ribs, thereby avoiding local stress on the swing arm and improving the swing stability of the swing arm.

[0013] In the transmission mechanism of the above-mentioned flat sewing machine, one side of the eccentric wheel has a counterweight part, and the counterweight part protrudes toward the side where the base circle is located along the radial direction of the eccentric wheel, and there is a gap between the counterweight part and the connecting rod along the axial direction of the main shaft, and a bearing is provided between the connecting rod and the eccentric wheel. This structure avoids setting a connection structure with the main shaft on the eccentric wheel, so that the rotational force of the main shaft is stably transmitted to the eccentric wheel. The gap setting avoids the interference between the rotation of the counterweight part and the movement of the connecting rod, and the eccentric wheel stably transmits the power to the connecting rod through the bearing. This structure improves the stability of power transmission; the counterweight part is a part of the eccentric wheel, that is, the counterweight part and the eccentric wheel are an integrated structure. The present application adds a counterweight part on the basis of the existing eccentric wheel, and limits the protruding direction of the counterweight part. When the main shaft rotates, the counterweight part can offset the inertia generated by the eccentric wheel rotating with the main shaft, thereby ensuring the rotation stability of the eccentric wheel.

[0014] In the transmission mechanism of the above-mentioned flat sewing machine, the counterweight part is fan-shaped and has a center hole for the main shaft to pass through. A number of connection holes extending to the center hole are opened on the outer arc surface of the counterweight part along the circumference of the main shaft, and bolts are inserted into the connection holes to make the eccentric wheel rotate synchronously with the main shaft. This structure improves the connection stability between the counterweight part and the main shaft. The bolts can be clamping bolts, and the connection between the counterweight part and the main shaft is achieved by tightening along the circumference of the main shaft. The counterweight part is sleeved on the main shaft to increase the contact area between the eccentric wheel and the support plate, and the protruding direction of the counterweight part is set opposite to the protruding direction of the eccentric wheel, so that the inertia generated by the rotation of the eccentric wheel with the main shaft is offset by the counterweight part. On this basis, a connection hole is opened on the outer arc surface of the counterweight part so that the bolts are against the main shaft around the circumference of the main shaft. This structure further improves the connection stability between the eccentric wheel and the main shaft.

[0015] In the transmission mechanism of the above-mentioned flat-bed sewing machine, the transmission mechanism also includes a swing frame rotatably connected to the frame, and the crank group includes at least one pair of cranks, in which one end of the two cranks is hinged to the connecting rod, and the end of one crank away from the connecting rod is hinged to the swing arm, and the end of the other crank away from the connecting rod is hinged to the swing frame. This structure allows the swing arm to swing around the hinge point where the crank and the swing frame are hinged under the drive of the connecting rod, and this structure determines the swing trajectory of the swing arm; further, since the moving stroke of the connecting rod is determined, and the swing frame is rotatably connected to the frame, the position of the hinge point can be changed by adjusting the angle of the swing frame, so that the swing amplitude of the swing arm is adjustable, and the swing amplitude of the swing arm is the stitch length of the sewing machine, and this structure makes it easy to adjust the stitch length of the sewing machine.

[0016] In the transmission mechanism of the above-mentioned flat-bed sewing machine, the swing frame has a U-shaped clearance groove, the crank group includes two pairs of cranks, both pairs of cranks are located in the clearance groove, the swing arm and the connecting rod are located between the two pairs of cranks, and the connection between the swing arm and the crank is located at the notch of the clearance groove. The two pairs of cranks further improve the stability of power transmission, and because the swing amplitude of the swing arm is not uniquely determined, the swing amplitude range of the swing arm is increased by setting the connection position of the swing arm and the crank.

[0017] Compared with the prior art, the transmission mechanism of a lockstitch sewing machine provided by the utility model has the following advantages: the eccentric wheel converts the rotational motion of the main shaft into the up and down reciprocating motion of the connecting rod, and the connecting rod drives the swing arm to swing through the crank set. On the one hand, the upper feed shaft and the lower feed shaft swing synchronously with the swing arm, and on the other hand, the presser foot assembly and the cloth feed assembly share a set of transmission structure, thereby simplifying the transmission structure while ensuring the consistency of the upper and lower feeding of the sewing machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the transmission mechanism of the lockstitch sewing machine installed in the frame.

[0019] Figure 2 It is a structural schematic diagram of the transmission mechanism of the lockstitch sewing machine.

[0020] Figure 3 yes Figure 2 main view.

[0021] Figure 4 yes Figure 2 Exploded diagram.

[0022] In the figure, 1, frame; 2, main shaft; 3, upper feed shaft; 4, lower feed shaft; 5, eccentric wheel; 51, counterweight; 52, center hole; 53, connecting hole; 6, swing arm; 61, first side rod; 62, second side rod; 63, mounting hole; 7, connecting rod; 71, bearing; 8, crank group; 81, crank; 9, reinforcement structure; 91, reinforcement rib; 92, reinforcement area; 10, swing frame; 101, give way groove; 11, connecting rod group; 12, presser foot assembly; 13, cloth feeding assembly. DETAILED DESCRIPTION

[0023] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0024] like Figure 1 As shown in FIG. 1 , the transmission mechanism of the flat-bed sewing machine comprises a frame 1 on which a main shaft 2, an upper feed shaft 3 for connecting a presser foot assembly and a lower feed shaft 4 for connecting a cloth feed assembly are arranged. Figure 2 As shown, an eccentric wheel 5 is sleeved on the main shaft 2, and the transmission mechanism includes a swing arm 6 connected to the upper feed shaft 3 and the lower feed shaft 4 and a connecting rod 7 with one end sleeved outside the eccentric wheel 5, a bearing 71 is provided between the connecting rod 7 and the eccentric wheel 5, and the other end of the connecting rod 7 is provided with a crank group 8 which connects the connecting rod 7 and the swing arm 6 and drives the swing arm 6 to swing when the eccentric wheel 5 rotates; the swing arm 6 is in the shape of an elongated strip, one end of the swing arm 6 is connected to the upper feed shaft 3, and the other end is connected to the lower feed shaft 4 through a connecting rod group 11, and the connecting rod group 11 includes a small crank 81 connected to the lower feed shaft 4 and a connecting rod, and the two ends of the connecting rod are hinged to the swing arm 6 and the small crank 81.

[0025] like Figure 2-Figure 4As shown, the swing arm 6 has a reinforcing structure 9 for improving its own strength. In the present application, the reinforcing structure 9 includes a plurality of reinforcing ribs 91 which are fixedly connected to the swing arm 6 and divide the inside of the swing arm 6 into four reinforcing areas 92. The reinforcing area 92 is a hollow area inside the swing arm 6. The reinforcing ribs 91 ensure that the swing arm 6 has good rigidity, so that the swing arm 6 is not easily deformed under conditions of large transmission force, thereby ensuring the stability of power transmission. The reinforcing area 92 ensures that the swing arm 6 is lightweight, reduces the loss of power transmission, and ensures the stability of the swing of the swing arm 6. The swing arm 6 has a first side rod 61 and a second side rod 62 connected at the ends, and there is a gap between the first side rod 61 and the second side rod 62. The reinforcing ribs 91 connect the first side rod 61 and the second side rod 62 to divide the gap into the above-mentioned four reinforcement areas 92. The reinforcement areas 92 are all triangular in shape. The number of the reinforcing ribs 91 is three. The three reinforcing ribs 91 are arranged along the length direction of the first side rod 61 and intersect at the second side rod 62. The second side rod 62 is provided with a mounting hole 63 for connecting the crank group 8 at the intersection of the three reinforcing ribs 91. In this embodiment, the reinforcement structure 9 includes three reinforcing plates fixedly connected to the outside of the swing arm 6 and spaced apart along the length direction of the swing arm 6. The reinforcing plates are L-shaped, and both ends of the reinforcing plates are fixedly connected to one side of the swing arm 6.

[0026] One side of the eccentric wheel 5 has a sector-shaped counterweight 51, which protrudes along the radial direction of the eccentric wheel 5 toward the side where the base circle is located. The counterweight 51 has a center hole 52 for the main shaft 2 to pass through, and a connecting hole 53 that passes through the sector surface of the counterweight 51 is opened on the hole wall of the center hole 52. The fastening bolts are passed through the connecting holes 53 and pressed against the outer peripheral surface of the main shaft 2 to connect the eccentric wheel 5 to the main shaft 2. In this embodiment, the number of connecting holes 53 is three. In actual production, the number of connecting holes 53 can be two or four. The eccentric wheel 5 and the counterweight 51 are an integrated structure.

[0027] The transmission mechanism also includes a swing frame 10 rotatably connected to the frame 1, the swing frame 10 has a U-shaped clearance groove 101, the crank group 8 includes two pairs of cranks 81, the two pairs of cranks 81 are both located in the clearance groove 101, and the swing arm 6 and the connecting rod 7 are both located between the two pairs of cranks 81. Figure 3 As shown, there is a gap between the upper end of the swing arm 6 and the connecting rod 7 along the axial direction of the main shaft 2 to avoid interference between the connecting rod 7 and the swing arm 6 when the connecting rod 7 moves. The connecting rod 7 is connected to one end of the four cranks 81 through a transmission pin. One end of one crank 81 in each pair of cranks 81 away from the connecting rod 7 is hinged to the swing arm 6, and the other end of the other crank 81 in each pair of cranks 81 away from the connecting rod 7 is hinged to the swing frame 10. The connection between the swing arm 6 and the crank 81 is located at the notch of the give way groove 101.

[0028] The motor power output connected to the main shaft 2 drives the main shaft 2 to rotate, and the connecting rod 7 converts the rotation of the eccentric wheel 5 into an up and down reciprocating motion, driving the crank 81 to rotate around the hinge point of the swing frame 10, so that the swing arm 6 swings. On the one hand, the crank 81 drives the upper feed shaft 3 to swing, and on the other hand, the crank 81 drives the lower feed shaft 4 to swing through the connecting rod group 11, so that the upper feed shaft 3 and the lower feed shaft 4 swing synchronously, thereby realizing the upper and lower synchronous feeding of the sewing machine.

[0029] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or additions to the specific embodiments described or replace them in a similar manner, but this will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0030] Although the present invention uses more terms such as frame 1, spindle 2, upper feed shaft 3, lower feed shaft 4, eccentric wheel 5, counterweight 51, center hole 52, connecting hole 53, swing arm 6, first side rod 61, second side rod 62, mounting hole 63, connecting rod 7, bearing 71, crank set 8, crank 81, reinforcement structure 9, reinforcement rib 91, reinforcement area 92, swing frame 10, clearance groove 101, connecting rod set 11, presser foot assembly 12, cloth feeding assembly 13, etc., it does not exclude the possibility of using other terms. The use of these terms is only for more convenient description and explanation of the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. A transmission mechanism of a lockstitch sewing machine, the lockstitch sewing machine comprising a frame (1), the frame (1) being provided with a main shaft (2), an upper feed shaft (3) for connecting a presser foot assembly (12), and a lower feed shaft (4) for connecting a cloth feed assembly (13), wherein: An eccentric wheel (5) is sleeved on the main shaft (2), and the transmission mechanism comprises a swing arm (6) connecting the upper feeding shaft (3) and the lower feeding shaft (4) and a connecting rod (7) with one end sleeved outside the eccentric wheel (5). The other end of the connecting rod (7) is provided with a crank group (8) connecting the connecting rod (7) and the swing arm (6) and driving the swing arm (6) to swing when the eccentric wheel (5) rotates. The swing arm (6) has a reinforcing structure (9) for improving its own strength.

2. The transmission mechanism of the lockstitch sewing machine according to claim 1, characterized in that: The swing arm (6) is in the shape of an elongated strip, one end of the swing arm (6) is connected to the upper feed shaft (3), and the other end is connected to the lower feed shaft (4), the reinforcement structure (9) comprises a plurality of reinforcement ribs (91) fixedly connected to the inside of the swing arm (6), and the reinforcement ribs (91) divide the inside of the swing arm (6) into four reinforcement areas (92) along the length direction of the swing arm (6).

3. The transmission mechanism of the lockstitch sewing machine according to claim 2, characterized in that: The swing arm (6) comprises a first side rod (61) and a second side rod (62) connected at their ends, a gap is provided between the first side rod (61) and the second side rod (62), and the reinforcing rib (91) connects the first side rod (61) and the second side rod (62) to divide the gap into the above-mentioned four reinforcing areas (92).

4. The transmission mechanism of the lockstitch sewing machine according to claim 3, characterized in that: A plurality of reinforcing ribs (91) are arranged along the length direction of the first side bar (61) and intersect at the second side bar (62), and the reinforcing areas (92) are all triangular in shape.

5. The transmission mechanism of the lockstitch sewing machine according to claim 4, characterized in that: The number of the reinforcing ribs (91) is three, and the second side rod (62) is provided with a mounting hole (63) for connecting to a crank assembly (8) at the intersection of the three reinforcing ribs (91).

6. The transmission mechanism of a lockstitch sewing machine according to any one of claims 1 to 5, characterized in that: The eccentric wheel (5) has a counterweight portion (51) on one side, the counterweight portion (51) protrudes along the radial direction of the eccentric wheel (5) toward the side where the base circle thereof is located, and there is a gap between the counterweight portion (51) and the connecting rod (7) along the axial direction of the main shaft (2), and a bearing (71) is provided between the connecting rod (7) and the eccentric wheel (5).

7. The transmission mechanism of the lockstitch sewing machine according to claim 6, characterized in that: The counterweight portion (51) is fan-shaped and has a center hole (52) for the main shaft (2) to pass through. A plurality of connecting holes (53) extending to the center hole (52) are provided on the outer arc surface of the counterweight portion (51) along the circumference of the main shaft (2). Bolts are passed through the connecting holes (53) so that the eccentric wheel (5) rotates synchronously with the main shaft (2).

8. The transmission mechanism of a lockstitch sewing machine according to any one of claims 1 to 5, characterized in that: The transmission mechanism also includes a swing frame (10) rotatably connected to the frame (1); the crank group (8) includes at least one pair of cranks (81); one end of each of the two cranks (81) is hinged to the connecting rod (7); one end of one crank (81) away from the connecting rod (7) is hinged to the swing arm (6); and the other end of the other crank (81) away from the connecting rod (7) is hinged to the swing frame (10).

9. The transmission mechanism of the lockstitch sewing machine according to claim 8, characterized in that: The swing frame (10) has a U-shaped clearance groove (101), the crank group (8) comprises two pairs of cranks (81), the two pairs of cranks (81) are both located in the clearance groove (101), the swing arm (6) and the connecting rod (7) are both located between the two pairs of cranks (81), and the connection between the swing arm (6) and the crank (81) is located at the notch of the clearance groove (101).

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