CN110685078A

CN110685078A - Plane sewing device

Info

Publication number: CN110685078A
Application number: CN201911015136.9A
Authority: CN
Inventors: 窦倩; 王冻洋; 邵新平; 申亚欣
Original assignee: Ningbo Taiping Fashion Costume Creative Research Institute Co Ltd
Current assignee: Ningbo Taiping Fashion Costume Creative Research Institute Co Ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2020-01-14

Abstract

The invention discloses a plane sewing device which comprises a sewing machine main body, wherein a vertical plate is installed at the center of the top end of the left side of the sewing machine main body, a switch box is connected with the top end of the left side of the vertical plate through a screw, a PLC is connected with the top end of the vertical plate through a screw, the PLC is respectively and electrically connected with the switch box and a control system of the sewing machine main body, a vertically arranged base plate is installed on the right side of the vertical plate, an air cylinder is connected with the right side of the base plate through a screw, the air cylinder is electrically connected with the PLC, and a pressing mechanism is installed at the bottom end. This plane sewing device can realize the automatic sewing processing of cloth, and the conveying speed of cloth is stable when the sewing, and the deviation can not appear in the sewing line, has improved product quality, can carry different types of cloth moreover, and the practicality is strong, can make the staff have more time to do other work, has improved machining efficiency, great demand that has satisfied clothing production.

Description

Plane sewing device

Technical Field

The invention relates to the technical field of garment processing, in particular to a plane sewing device.

Background

The sewing machine is a machine which uses one or more sewing threads to form one or more stitches on a sewing material to enable one or more layers of sewing materials to be interwoven or sewn, the plane sewing is manual sewing, generally, workers manually and slowly creep to push the cloth, the sewing machine is enabled to sew the cloth, such as serging and the like, along with the development of the times, the clothing industry gradually draws close to automatic production, the traditional method is adopted to process the cloth, the conveying speed of the cloth cannot be accurately controlled by manual operation, the deviation of sewing lines is easy to occur, the product quality is reduced, the two hands of the workers need to be always placed on the sewing machine, the two hands cannot be left to do corresponding other work, the processing efficiency is reduced, and the requirement of the clothing production is difficult to meet.

Disclosure of Invention

The present invention is directed to a flat sewing machine to solve the above problems of the related art.

In order to achieve the purpose, the invention provides the following technical scheme: a plane sewing device comprises a sewing machine main body, wherein a vertical plate is installed at the center of the top end of the left side of the sewing machine main body, a switch box is connected with the top end of the left side of the vertical plate through a screw, a PLC is connected with the top end of the vertical plate through a screw, the PLC is electrically connected with the switch box and a control system of the sewing machine main body respectively, a vertically arranged base plate is installed on the right side of the vertical plate, an air cylinder is connected with the right side of the base plate through a screw, the air cylinder is electrically connected with the PLC, a pressing mechanism is installed at the bottom end of the air cylinder, and a conveying mechanism is installed;

the pressing mechanism comprises a supporting plate, the left side of the top end of the supporting plate is in screwed connection with the bottom end of the air cylinder, the right side of the upper surface of the supporting plate is provided with a ring groove, the outer side wall of the ring groove is provided with a clamping groove along the circumferential direction, the right side of the bottom end of the supporting plate is provided with a U-shaped plate along the front-back direction, the center position of the bottom end of the inner cavity of the U-shaped plate is rotatably connected with a screw rod through a bearing, the axis of the screw rod and the center point of the ring groove are on the same vertical line, the top end of the screw rod extends out of the upper surface of the supporting plate and is provided with a shell, the front side of the upper surface and the lower surface of the shell is provided with a slide way, the inner cavity of the shell is provided with a first guide rod along the front-back direction, the top end of the T-shaped plate is provided with a pull rod, the top end of the pull rod penetrates through the inner cavity of the slide way, the central position of the outer wall of the screw rod is in threaded connection with a rectangular plate, the front side and the rear side of the bottom end of the rectangular plate are respectively provided with one end of a second guide rod, the other end of the second guide rod extends out of the lower surface of the U-shaped plate and is provided with a first transverse plate, the front side and the rear side of the first transverse plate are respectively in shaft connection with one end of a first connecting rod inclining towards the outside, the other end of the first connecting rod is in shaft connection with one end of a second connecting rod, the other end of the second connecting rod is in shaft connection with a horizontally arranged second transverse plate, the front side and the rear side of the top end;

the conveying mechanism comprises a return plate, the top end of the return plate is in screwed connection with the bottom end of the second transverse plate, the left rear end of the return plate is in screwed connection with a servo motor, the servo motor is electrically connected with a PLC (programmable logic controller), the output end of the servo motor extends to the inner cavity of the return plate and is locked by a coupler to form a first rotating shaft, the right side of the first rotating shaft extends out of the right side wall of the return plate, the outer wall of the first rotating shaft is in rotary connection with the return plate through a bearing, the left side of the outer wall of the first rotating shaft is in key connection with a driving sprocket, the front side of the right inner wall of the return plate is in rotary connection with a second rotating shaft through a bearing, the left side of the outer wall of the second rotating shaft is in key connection with a driven sprocket, the driven sprocket is in rotary connection with the driving sprocket through a chain, the right side of the second rotating shaft extends out of the right side of the return, and the four rollers are positioned on the same horizontal plane, and the presser foot of the sewing machine main body is positioned among the four rollers.

Preferably, the width of the inner cavity of the annular groove is larger than the length of the fixture block.

Preferably, the number of the clamping grooves is twelve, and the twelve clamping grooves are distributed on the outer side wall of the annular groove at intervals of 30 degrees clockwise.

Preferably, the shape of the fixture block is a trapezoid.

Preferably, the first link and the second link are the same size.

Preferably, the drive sprocket and the driven sprocket are the same size.

Compared with the prior art, the invention has the beneficial effects that: the plane sewing device is in practical use, the conveying mechanism is pushed to move downwards by the thrust of the air cylinder, when the rollers are in contact with cloth, the included angle between the first connecting rod and the second connecting rod is reduced under the pushing action of the air cylinder, the distance between the first transverse plate and the second transverse plate is reduced to extrude the second spring, meanwhile, the rollers can be pressed on the cloth by the second spring by utilizing the self elasticity, then, the sewing machine main body and the servo motor are started, the four rollers can simultaneously rotate clockwise under the driving of the servo motor through the matching of the driving chain wheel, the chain and the driven chain wheel, the cloth rolled by the rollers can stably move towards the rear side, the sewing machine main body continuously sews the cloth, when the pressing force of the rollers on the cloth needs to be adjusted, the pull rod is pulled to move towards the rear side, the clamping block can move towards the rear side through the matching of the first guide rod and the T-shaped plate to be separated from the, the limiting displacement through the second guide arm can make the rectangular plate upwards or move downwards, thereby make the interval between the mesa of gyro wheel and sewing machine main part can grow or diminish, alright reduce or increase the packing force of gyro wheel to the cloth, the fixture block can move to the outside under the effect of first spring and insert in the corresponding draw-in groove, alright fixed to the casing after the removal, thereby can realize the automatic sewing processing of cloth, the conveying speed of cloth is stable when the sewing, the deviation can not appear in the sewing circuit, product quality is improved, and can carry different types of cloth, therefore, the clothes hanger is strong in practicability, can make the staff have more times to do other work, machining efficiency is improved, great demand for clothing production has been satisfied.

Drawings

FIG. 1 is a front view of the present invention;

FIG. 2 is a right side cross-sectional view of the hold-down mechanism of the present invention;

FIG. 3 is a top view of the support plate of the present invention;

FIG. 4 is an enlarged view of the invention at A;

FIG. 5 is a schematic diagram of a fixture block structure according to the present invention;

fig. 6 is a top cross-sectional view of the conveying mechanism of the present invention.

In the figure: 1. the sewing machine comprises a sewing machine main body, 2, a vertical plate, 3, a base plate, 4, a cylinder, 5, a pressing mechanism, 501, a supporting plate, 502, an annular groove, 503, a clamping groove, 504, a U-shaped plate, 505, a screw rod, 506, a shell, 507, a first guide rod, 508, a T-shaped plate, 509, a first spring, 510, a clamping block, 511, a pull rod, 512, a rectangular plate, 513, a second guide rod, 514, a first transverse plate, 515, a first connecting rod, 516, a second connecting rod, 517, a second transverse plate, 518, a second spring, 6, a conveying mechanism, 601, a clip plate, 602, a servo motor, 603, a first rotating shaft, 604, a driving sprocket, 605, a second rotating shaft, 606, a driven sprocket, 607, a chain, 608, a roller, 7, a switch box, 8 and a PLC controller.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-6, the present invention provides a technical solution: a plane sewing device comprises a sewing machine main body 1, wherein the sewing machine main body 1 is an electric sewing machine with model number 9800D and is used for sewing and processing cloth, a vertical plate 2 is installed at the center position of the top end of the left side of the sewing machine main body 1, a switch box 7 is connected with the top end of the left side of the vertical plate 2 through a screw, the model number of the switch box 7 is LA4-3H and is used for controlling a PLC (programmable logic controller) 8, the top end of the vertical plate 2 is connected with the PLC 8 through the screw, the PLC 8 is respectively and electrically connected with a control system of the switch box 7 and the sewing machine main body 1, the model number of the PLC 8 is FX3U-16 and is used for controlling the start and stop of the sewing machine main body 1, an air cylinder 4 and a servo motor 602, a vertically arranged base plate 3 is installed on the right side of the vertical plate 2, an air cylinder 4 is connected with the screw on the right side of the base plate 3, the pressing mechanism is used for pushing the supporting plate 501 to move downwards or upwards, the pressing mechanism 5 is installed at the bottom end of the air cylinder 4, and the conveying mechanism 6 is installed at the bottom end of the pressing mechanism 5;

the pressing mechanism 5 comprises a supporting plate 501, the left side of the top end of the supporting plate 501 is in screw connection with the bottom end of the air cylinder 4, the right side of the upper surface of the supporting plate 501 is provided with an annular groove 502, the outer side wall of the annular groove 502 is provided with a clamping groove 503 along the circumferential direction, the right side of the bottom end of the supporting plate 501 is provided with a U-shaped plate 504 along the front-back direction, the center position of the bottom end of the inner cavity of the U-shaped plate 504 is rotatably connected with a screw rod 505 through a bearing, the axis of the screw rod 505 and the center point of the annular groove 502 are on the same vertical line, the distance between the casing 506 and the annular groove 502 is kept unchanged during rotation, when the screw rod 505 rotates clockwise or anticlockwise, the thread of the outer wall of the screw rod 505 can enable the rectangular plate 512 to move upwards or downwards by using the self-rotating, a first guide rod 507 is installed in the cavity of the housing 506 along the front-back direction, the T-shaped plate 508 is limited by the first guide rod 507, and the T-shaped plate 508 can be ensured to keep horizontal movement, so that the fixture block 510 can be stably switched back and forth between the annular groove 502 and the clamping groove 503, the outer wall of the first guide rod 507 is respectively sleeved with the T-shaped plate 508 and a first spring 509 providing front side elasticity for the T-shaped plate 508 from front to back, the first spring 509 is a rotary spring with an elasticity coefficient of 35N/CM, the first spring 509 generates elastic deformation after being stretched or extruded, and is restored to an initial state after external force is removed, the fixture block 510 completely inserted into the clamping groove 503 is installed in the cavity of the T-shaped plate 508 penetrating through the slideway at the bottom end, a pull rod 511 is installed at the top end of the T-shaped plate 508, the cavity of the slideway penetrates through the top end of the pull rod 511, a rectangular plate 512 is screwed in the center position, the rectangular plate 512 is limited through a second guide rod 513, so that the rectangular plate 512 can only vertically move up and down, the other end of the second guide rod 513 extends out of the lower surface of the U-shaped plate 504 and is provided with a first transverse plate 514, the front side and the rear side of the first transverse plate 514 are respectively and axially connected with one end of a first connecting rod 515 which inclines outwards, the other end of the first connecting rod 515 is axially connected with one end of a second connecting rod 516, the other end of the second connecting rod 516 is axially connected with a second transverse plate 517 which is horizontally arranged, the front side and the rear side of the top end of the second transverse plate 517 are respectively and fixedly connected with one end of a second spring 518, the second spring 518 is a rotating spring, the elastic coefficient is 30N/CM, the second spring 518 generates elastic deformation after being stretched or extruded, the initial state is recovered after external force is removed, and the other end; the conveying mechanism 6 comprises a return plate 601, the top end of the return plate 601 is in screw connection with the bottom end of a second transverse plate 517, the rear end of the left side of the return plate 601 is in screw connection with a servo motor 602, the servo motor 602 is electrically connected with a PLC 8, the servo motor 602 is a low-speed micro motor with the model number GA12-N20 and is used for driving a first rotating shaft 603 to rotate clockwise, the output end of the servo motor 602 extends to the inner cavity of the return plate 601 and is locked with a first rotating shaft 603 through a coupler, the right side of the first rotating shaft 603 extends out of the right side wall of the return plate 601, the outer wall of the first rotating shaft 603 is in rotating connection with the return plate 601 through a bearing, the first rotating shaft 603 and a second rotating shaft 605 are on the same horizontal plane, it is ensured that four rollers 608 can be on the same horizontal plane, the left side of the outer wall of the first rotating shaft 603 is connected with a driving sprocket 604, the front side of, the left side of the outer wall of the second rotating shaft 605 is connected with a driven sprocket 606 in a key mode, the driven sprocket 606 is connected with a driving sprocket 604 in a rotating mode through a chain 607, the right side of the second rotating shaft 605 extends out of the right side wall of the return plate 601, the outer walls of the first rotating shaft 603 and the second rotating shaft 605 are located on the outer side portion of the return plate 601 and are provided with bilaterally symmetrical rollers 608, the four rollers 608 are located on the same horizontal plane, a presser foot of the sewing machine body 1 is located between the four rollers 608, the bottom end of each roller 608 is lower than the lower surface of the return plate 601, and the rollers 608 can be enabled to be in contact with cloth when moving downwards.

Preferably, the width of the inner cavity of the annular groove 502 is larger than the length of the latch 510, so that the latch 510 can completely enter the annular groove 502, and the latch 510 can be separated from the locking groove 503 to release the locking of the housing 506.

Preferably, the number of the clamping grooves 503 is twelve, and twelve clamping grooves 503 are distributed on the outer side wall of the annular groove 502 at intervals of 30 degrees clockwise, so that the rotated housing 506 can be braked from multiple directions through the twelve clamping grooves 503, and the movement of the screw 505 is conveniently controlled.

Preferably, the latch 510 is formed in a trapezoidal shape to reduce a left surface area of the latch 510, so that the latch 510 can be easily inserted into the latch 503 while being aligned with the latch groove 503 when the latch 510 moves outward by the first spring 509.

Preferably, the first connecting rod 515 and the second connecting rod 516 have the same size, and when the distance between the first transverse plate 514 and the second transverse plate 517 becomes larger or smaller, the included angle between the first connecting rod 515 and the second connecting rod 516 located on the same side becomes larger or smaller, and the left and right sides of the first transverse plate 514 and the second transverse plate 517 can be restricted by the cooperation of the two sets of the first connecting rod 515 and the second connecting rod 516, so that the first transverse plate 514 and the second transverse plate 517 can be kept horizontal all the time.

Preferably, the driving sprocket 604 and the driven sprocket 606 are the same in size, and the transmission ratio between the driving sprocket 604 and the driven sprocket 606 is 1:1, so that the four rollers 608 can rotate at the same speed and in the same direction, and the rollers 608 can convey the cloth conveniently.

The detailed connection means is a technique known in the art, and the following mainly describes the working principle and process, and the specific operation is as follows.

When in use, cloth to be sewn is placed on the table top of the sewing machine body 1, the cloth is aligned with the presser foot of the sewing machine body 1, the start button on the switch box 7 is pressed to enable the PLC 8 to control the cylinder 4 to start, the cylinder 4 pushes the pressing mechanism 5 and the conveying mechanism 6 to move downwards, when the roller 608 on the conveying mechanism 6 is contacted with the cloth, the first transverse plate 514 is pushed by the thrust of the cylinder 4 to extrude the first connecting rod 515 to move downwards, the first connecting rod 515 and the second connecting rod 516 are rotatably connected, so that the included angle between the first connecting rod 515 and the second connecting rod 516 is reduced, the first transverse plate 514 downwards extrudes the second spring 518 under the cooperation of the second transverse plate 517, so that the second spring 518 provides a downward elastic force for the roller 608 to enable the roller 608 to be pressed on the cloth, the switch on the switch box 7 is pressed again at the moment, so that the PLC 8 controls the sewing machine body 1 and the servo motor 602 to start, the sewing machine body 1 sews cloth, meanwhile, the servo motor 602 drives the driving gear 604 to rotate clockwise, the driven sprocket 606 rotates clockwise synchronously with the driving sprocket 604 under the driving action of the chain 607, so that the four rollers 608 can roll clockwise simultaneously to drive the cloth to move stably to the rear side, the sewing machine body 1 can sew continuously while the cloth moves, thereby realizing automatic conveying and sewing of the cloth, when the pressing force of the rollers 608 on the cloth needs to be adjusted according to different materials of the cloth, the pull rod 511 is pulled to the rear side, the T-shaped plate 508 and the fixture block 510 move to the rear side under the limiting action of the first guide rod 507 to press the first spring 509 until the fixture block 510 and the clamping groove 503 are separated from the annular groove 502, the fixing of the shell 506 is released, the shell 506 is pulled by the pull rod 511 to rotate clockwise or counterclockwise, and the screw 505 rotates clockwise or counterclockwise, the thread on the outer wall of the screw 505 can drive the rectangular plate 512 to move upwards or downwards under the action of the self-rotating force through the limit action of the second guide rod 513, so that the first transverse plate 514, the first connecting rod 515, the second connecting rod 516, the second transverse plate 517 and the conveying mechanism 6 can integrally move upwards or downwards, when the distance between the upward movement of the conveying mechanism 6 and the table top of the sewing machine body 1 is increased, the elastic force of the second spring 518 to the roller 608 can be reduced, when the distance between the downward movement of the conveying mechanism 6 and the table top of the sewing machine body 1 is decreased, the elastic force of the second spring 518 to the roller 608 can be increased, so that the pressing force of the roller 608 to the cloth can be reduced or increased according to the material of the cloth, the roller 608 can convey different kinds of cloth, when the shell 506 stops rotating, the pull rod 511 is released, the first spring 509 can push the fixture block 510 to move outwards through the T-shaped plate 508 to be inserted into the corresponding position of the, the movable shell 506 can be fixed, the shell 506 can be prevented from rotating due to vibration, the device can automatically sew the cloth, the cloth is conveyed stably, a sewing line is stable, the processing quality is improved, the pressing force of the roller 608 on the cloth can be adjusted according to different cloth materials, the device is suitable for conveying various kinds of cloth, and the device is more beneficial to wide popularization.

In the description of the present invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "one side", "top", "inner", "front", "center", "two ends", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated; also, unless expressly stated or limited otherwise, the terms "snap" or "coupling" or "engagement" or "welding" or "screwing" or "mounting" or "setting" are to be construed broadly, e.g., as a fixed connection, a detachable connection, or an integral part; can be mechanically or electrically connected; the terms may be directly connected or indirectly connected through an intermediate, and may be communication between two elements or interaction relationship between two elements, unless otherwise specifically limited, and the specific meaning of the terms in the present invention will be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A flat sewing device comprising a sewing machine body (1), characterized in that: a vertical plate (2) is installed at the center of the top end of the left side of the sewing machine main body (1), a switch box (7) is connected to the top end of the left side of the vertical plate (2) through a screw, a PLC (programmable logic controller) (8) is connected to the top end of the vertical plate (2) through a screw, the PLC (8) is electrically connected with the switch box (7) and a control system of the sewing machine main body (1) respectively, a vertically arranged base plate (3) is installed on the right side of the vertical plate (2), an air cylinder (4) is connected to the right side of the base plate (3) through a screw, the air cylinder (4) is electrically connected with the PLC (8), a pressing mechanism (5) is installed at the bottom end of the air cylinder (4), and a conveying mechanism (;

the pressing mechanism (5) comprises a supporting plate (501), the left side of the top end of the supporting plate (501) is in screw connection with the bottom end of the air cylinder (4), the right side of the upper surface of the supporting plate (501) is provided with an annular groove (502), the outer side wall of the annular groove (502) is provided with a clamping groove (503) along the circumferential direction, the right side of the bottom end of the supporting plate (501) is provided with a U-shaped plate (504) along the front-back direction, the center position of the bottom end of an inner cavity of the U-shaped plate (504) is rotatably connected with a screw rod (505) through a bearing, the axis of the screw rod (505) and the center point of the annular groove (502) are on the same vertical line, the top end of the screw rod (505) extends out of the upper surface of the supporting plate (501) and is provided with a shell (506), the front, the outer wall of the first guide rod (507) is respectively sleeved with a T-shaped plate (508) and a first spring (509) for providing front side elasticity for the T-shaped plate (508) from front to back, the bottom end of the T-shaped plate (508) penetrates through the inner cavity of the slide way and is provided with a clamping block (510) which is completely inserted into the clamping groove (503), the top end of the T-shaped plate (508) is provided with a pull rod (511), the top end of the pull rod (511) penetrates through the inner cavity of the slide way, the outer wall center position of the screw rod (505) is screwed with a rectangular plate (512), the front side and the back side of the bottom end of the rectangular plate (512) are respectively provided with one end of a second guide rod (513), the other end of the second guide rod (513) extends out of the lower surface of the U-shaped plate (504) and is provided with a first transverse plate (514), the front side and the back side of the first transverse plate (514) are respectively pivoted with one end of a first connecting, a second transverse plate (517) which is horizontally arranged is coupled to the other end of the second connecting rod (516), one end of a second spring (518) is clamped to the front side and the rear side of the top end of the second transverse plate (517), and the other end of the second spring (518) is clamped to the bottom end of the first transverse plate (514);

the conveying mechanism (6) comprises a return plate (601), the top end of the return plate (601) is in screw connection with the bottom end of a second transverse plate (517), the rear end of the left side of the return plate (601) is in screw connection with a servo motor (602), the servo motor (602) is electrically connected with a PLC (programmable logic controller) controller (8), the output end of the servo motor (602) extends to the inner cavity of the return plate (601) and is locked with a first rotating shaft (603) through a coupler, the right side of the first rotating shaft (603) extends out of the right side wall of the return plate (601), the outer wall of the first rotating shaft (603) is in rotating connection with the return plate (601) through a bearing, the left side of the outer wall of the first rotating shaft (603) is in key connection with a driving sprocket (604), the front side of the right inner wall of the return plate (601) is in rotating connection with a second rotating shaft (605) through a bearing, the left side of the outer wall of the second, the driven chain wheel (606) is rotatably connected with the driving chain wheel (604) through a chain (607), the right side of the second rotating shaft (605) extends out of the right side wall of the return plate (601), the outer walls of the first rotating shaft (603) and the second rotating shaft (605) are positioned at the outer part of the return plate (601) and are provided with bilaterally symmetrical rollers (608), the four rollers (608) are positioned on the same horizontal plane, and the presser foot of the sewing machine body (1) is positioned among the four rollers (608).

2. A flat sewing device according to claim 1, wherein: the width of the inner cavity of the annular groove (502) is larger than the length of the fixture block (510).

3. A flat sewing device according to claim 1, wherein: the number of the clamping grooves (503) is twelve, and the twelve clamping grooves (503) are distributed on the outer side wall of the annular groove (502) at intervals of 30 degrees clockwise.

4. A flat sewing device according to claim 1, wherein: the fixture block (510) is trapezoidal in shape.

5. A flat sewing device according to claim 1, wherein: the first connecting rod (515) and the second connecting rod (516) are the same in size.

6. A flat sewing device according to claim 1, wherein: the drive sprocket (604) and the driven sprocket (606) are the same size.