CN220887956U - Needle frame swing transmission mechanism for case sewing machine - Google Patents

Abstract

The needle frame swing transmission mechanism for the case sewing machine comprises a rear machine head and a front machine head, wherein the top of the rear machine head is provided with a lifting cylinder, the front part of the front machine head is also provided with an organic needle assembly, the front part of the rear machine head is provided with a rear swing shaft in a penetrating way, and the rear part of the front machine head is provided with a front swing shaft in a penetrating way; the needle frame swing transmission mechanism comprises a swing sliding rail piece, a sliding block, a transmission pin and a swing rocker arm, wherein the swing sliding rail piece, the sliding block, the transmission pin and the swing rocker arm are arranged between the rear machine head and the front machine head, the rear part of the swing sliding rail piece is connected with the rear swing shaft in a matched mode, the sliding block is arranged in the front part of the swing sliding rail piece in a sliding mode and can slide up and down in a reciprocating mode, the swing rocker arm is connected with the front swing shaft in a matched mode, and the transmission pin is arranged between the sliding block and the swing rocker arm and is connected with the sliding block and the swing rocker arm in a matched mode. The advantages are that: compact structure, small number of parts, small accumulation gap, stable and accurate transmission and good sewing effect.

Description

Needle frame swing transmission mechanism for case sewing machine

Technical Field

The utility model relates to the technical field of sewing machines, in particular to a needle frame swing transmission mechanism for a case sewing machine.

Background

A sewing machine is a machine that interweaves or sews one or more layers of stitching material by forming one or more stitches on the stitching material with one or more stitching threads. The sewing machine can sew cotton, hemp, silk, wool, artificial fiber and other fabrics, leather, plastic, paper and other products, and the sewn stitch is neat, beautiful, flat, firm, fast in sewing speed and simple and convenient to use. And the artistic forms of hand-push embroidery, computerized embroidery and the like are derived from the hand-push embroidery. The bag sewing machine is one of the most common sewing machines for making bags, can also be called an industrial flat sewing machine, can be used for sewing fabrics, linings and other various details of the bags, and has the advantages of high speed, uniform stitching and convenient regulation of the tension of threads. Most of the existing case sewing machines cannot be lifted by the aid of presser foot lifting quantity, and the lifting height of the existing case sewing machines cannot enable cases to be sleeved on a lower needle plate of the case sewing machines. The other suitcase sewing machine is a lifting arm type suitcase machine with a machine head formed by two sections, wherein the machine head is divided into a front machine head capable of lifting up and down and a fixed rear machine head, the front machine head of the lifting arm type suitcase sewing machine can lift up under the action of an air cylinder, and then the suitcase is sleeved on a lower needle plate of the machine head; however, because the machine head of the case sewing machine is divided into a front section and a rear section, the needle frame swinging shafts in the front machine head and the rear machine head are provided with conversion transmission devices at the disconnection positions, and particularly the rear machine head is internally provided with the swinging shafts for transmitting the needle frame swinging, and the swinging shafts transmit the swinging force to the swinging shafts in the front machine head through the transmission of a first universal joint, a first connecting pin, a second universal joint, a spline, a third universal joint, a second connecting pin and a fourth universal joint of the conversion transmission devices, and finally the needle frame swings to complete the sewing operation of the case. However, because this set of drive mechanism involves too many parts, its inside includes five sets of drive structure, and this kind of complicated drive structure can lead to accumulating the clearance too big in the course of the work, makes at last because the inside existence in back clearance of drive structure when making up the operation, the needle in the needle holder appears the deviation easily when colluding the line operation to appear leaking the needle, lead to making up the effect relatively poor, even the needle can insert down the feeding tooth, causes the broken needle, makes the security relatively poor.

In view of the above, there is a need for a rational improvement in the structure of the drive assembly of existing case sewing machines. To this end, the inventors have advantageously devised that the technical solutions described below are created in this context.

Disclosure of utility model

The utility model aims to provide a needle frame swing transmission mechanism for a case sewing machine, which has the advantages of simple structure, stable transmission, reliability and durability, is beneficial to effectively reducing the generation of gaps by simplifying the number of internal transmission mechanisms and parts, ensures the stability of a needle assembly during swing operation, and ensures the stability and accuracy of transmission.

The utility model aims to achieve the purpose, namely a needle frame swing transmission mechanism for a case sewing machine, which comprises a rear machine head and a front machine head, wherein the front machine head is arranged at the front position of the rear machine head, the top end of the front part of the rear machine head is also provided with a lifting cylinder, the front machine head can reciprocate up and down under the driving of the lifting cylinder, the front position of the front machine head is also provided with a needle assembly for sewing cases, the front part of the rear machine head is provided with a rear swing shaft capable of swinging in a penetrating way, and the rear part of the front machine head is provided with a front swing shaft in a penetrating way; the characteristics are that: the needle frame swing transmission mechanism comprises a swing sliding rail piece, a sliding block, a transmission pin and a swing rocker arm, wherein the swing sliding rail piece, the sliding block, the transmission pin and the swing rocker arm are arranged between the rear machine head and the front machine head, the rear part of the swing sliding rail piece is connected with the rear swing shaft in a matched mode, the sliding block is slidingly arranged in the front part of the swing sliding rail piece and can slide up and down in a reciprocating mode, the swing rocker arm is connected with the front swing shaft in a matched mode, and the transmission pin is arranged between the sliding block and the swing rocker arm and is connected with the sliding block in a matched mode.

In a specific embodiment of the present utility model, the swing rail member has a cylindrical rear swing axle locking cylinder and a vertical rail; the rear swing shaft locking cylinder is transversely arranged in a state of being parallel to the horizontal direction, and is sleeved on the shaft body of the rear swing shaft and fixedly connected with the shaft body of the rear swing shaft; the vertical sliding rail is integrally formed at the end part of the rear swing shaft locking cylinder far away from the rear swing shaft, the vertical sliding rail is arranged in an extending mode parallel to the vertical direction, a sliding guide groove is formed in the surface of one side of the vertical sliding rail, which faces the sliding block, the sliding guide groove is vertically arranged and extends from the top end to the bottom end of the vertical sliding rail body, and the sliding block is installed in the sliding guide groove in a matched mode and can vertically slide in the sliding guide groove in a reciprocating mode.

In another specific embodiment of the present utility model, the sliding block is in a rectangular block shape configuration, the sliding guide groove is in a vertical square groove shape configuration, and the shape of the sliding guide groove is adapted to the shape of the sliding block.

In yet another embodiment of the present utility model, the drive pin is provided with a drive pin locating plate, a drive pin threaded section and a drive pin locking shaft; the transmission pin thread section and the transmission pin locking shaft are respectively formed at the front side and the rear side of the transmission pin positioning plate, and both extend along the horizontal direction; and the sliding block is also provided with a sliding block locking hole, the shape of the sliding block locking hole is matched with that of the transmission pin locking shaft, and the transmission pin locking shaft is matched and penetrated in the sliding block locking hole and is connected with the sliding block body, so that the matched connection of the transmission pin and the sliding block is realized.

In yet another specific embodiment of the present utility model, the swing arm has a front swing axle lock cylinder and a swing arm lower sleeve; the lower sleeve of the swing rocker arm is integrally formed at the lower position of the locking cylinder of the front swing shaft, a threaded hole of the lower sleeve of the swing rocker arm is further formed in the lower sleeve of the swing rocker arm, and a threaded section of a transmission pin of the transmission pin is arranged in the threaded hole of the lower sleeve of the swing rocker arm in a penetrating manner and is in threaded fit with the threaded section of the lower sleeve of the swing rocker arm, so that the fixed connection of the transmission pin and the lower sleeve of the swing rocker arm is realized.

In a further specific embodiment of the present utility model, the front swing shaft locking cylinder is disposed transversely in a state parallel to the horizontal direction, the front swing shaft extends from the rear portion of the front machine head body toward the rear portion, and the front swing shaft locking cylinder is sleeved on the shaft body of the front swing shaft and is fixedly connected with the shaft body, so that the swing rocker arm and the front swing shaft are connected in a matched manner.

In a further specific embodiment of the utility model, a rear nose platform is mounted on the front top end of the rear nose, and the rear nose platform extends towards the front along the horizontal direction; the lifting cylinder is positioned and installed at the front end part of the rear machine head platform, the lifting cylinder is provided with a piston rod arranged at the lower part of the cylinder body, the piston rod extends downwards along the vertical direction and can reciprocate up and down, the top end part of the front machine head is also provided with a front machine head matching sleeve seat, and the piston rod is matched and arranged in the front machine head matching sleeve seat in a penetrating way, so that the piston rod can drive the front machine head and the machine needle assembly to move up and down.

In a further specific embodiment of the utility model, a front nose accommodating cavity is formed at the front position of the front nose, and the needle assembly is arranged in the front nose accommodating cavity and protrudes downwards; the needle assembly comprises a needle frame, a needle body and an inner pressure foot, wherein the needle frame is arranged on the body of the front machine head, the inner pressure foot is arranged at the bottom of the needle frame in a matched mode, the inner pressure foot is used for pressing the surface of the case, the needle body is arranged in the needle frame in a penetrating mode, and the needle body can reciprocate up and down and penetrate through the inner pressure foot to sew the case.

The utility model has the beneficial effects that due to the adoption of the structure, the utility model has the following advantages: firstly, the needle frame swing transmission mechanism adopts a connection mode of sliding blocks and swing sliding rail pieces in a sliding fit manner, a transmission gap exists in the whole group of structures, the accumulation gap of the whole transmission mechanism is minimized by a single group of transmission gaps, the number of whole parts of the transmission mechanism is small, the structure compactness is effectively improved, the production cost can be effectively reduced, the transmission gap is small, the transmission is stable and accurate, the stable and reliable operation of a needle assembly is ensured, the abrasion resistance is realized, the occurrence of the needle breakage condition can be avoided, and the needle frame swing transmission mechanism is safer, more reliable, more convenient and more efficient; secondly, when the lifting cylinder controls the front machine head to move upwards, the sliding block can slide upwards in the sliding guide groove of the swinging guide rail piece, the vertically arranged sliding guide groove can ensure the accuracy of the movement track of the sliding block, the guiding function is good, and when the front machine head falls back downwards, the sliding block slides to the original position in the sliding guide groove, so that the transmission is accurate and reliable, and the transmission position is accurate.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present utility model.

In the figure: 1. rear machine head, 11, rear swing shaft, 12, rear machine head platform; 2. front nose, 21, front pendulum shaft, 22, front nose cooperation sleeve seat, 23, front nose holding cavity; 3. lifting cylinder, 31. Piston rod; 4. needle assembly, 41, needle frame, 42, needle body, 43, inner presser foot; 5. swing sliding rail pieces, 51, a rear swing shaft locking cylinder, 52, vertical sliding rails, 521 and a sliding guide groove; 6. a slider, 61. Slider locking holes; 7. the driving pin, 71, driving pin locating plate, 72, driving pin thread section, 73, driving pin locking shaft; 8. swing rocker arm, 81, front swing shaft locking cylinder, 82, swing rocker arm lower sleeve, 821, swing rocker arm lower sleeve threaded hole.

Detailed Description

The following detailed description of specific embodiments of the utility model, while given in connection with the accompanying drawings, is not intended to limit the scope of the utility model, and any changes that may be made in the form of the inventive concepts described herein, without departing from the spirit and scope of the utility model.

In the following description, any reference to the directions or azimuths of up, down, left, right, front and rear is based on the positions shown in the corresponding drawings, and therefore, should not be construed as a limitation on the technical solutions provided by the present utility model.

Referring to fig. 1, there is shown a needle frame swing transmission mechanism for a case sewing machine, the case sewing machine includes a rear head 1 and a front head 2, the front head 2 is mounted at a front position of the rear head 1, a lift cylinder 3 is further disposed at a top end of a front portion of the rear head 1, the front head 2 can reciprocate up and down under the driving of the lift cylinder 3, a needle assembly 4 for sewing a case is further mounted at a front position of the front head 2, a swing rear shaft 11 capable of swinging is disposed at a front portion near-bottom end position of the rear head 1, and a swing front shaft 21 is disposed at a rear portion near-bottom end position of the front head 2.

The technical key points of the technical scheme provided by the utility model are as follows: the needle frame swing transmission mechanism comprises a swing slide rail piece 5, a sliding block 6, a transmission pin 7 and a swing rocker arm 8 which are arranged between the rear machine head 1 and the front machine head 2, wherein the rear part of the swing slide rail piece 5 is matched and connected with the rear rocker shaft 11, the sliding block 6 is slidingly arranged in the front part of the swing slide rail piece 5 and can slide up and down in a reciprocating manner, the swing rocker arm 8 is matched and connected with the front rocker shaft 21, and the transmission pin 7 is arranged between the sliding block 6 and the swing rocker arm 8 and is matched and connected with the sliding block 6 and the swing rocker arm 8.

In the present embodiment, the swing rail 5 has a cylindrical rear swing axle locking cylinder 51 and a vertical rail 52; the rear swing shaft locking cylinder 51 is transversely arranged in a state parallel to the horizontal direction, the rear swing shaft locking cylinder 51 is sleeved on the shaft body of the rear swing shaft 11 and is fixedly connected with the shaft body of the rear swing shaft 11, and the rear swing shaft locking cylinder 51 is fixedly connected with the rear swing shaft 11 through a key pin connection mode; the vertical sliding rail 52 is integrally formed at an end portion of the rear swing shaft locking cylinder 51 away from the rear swing shaft 11, the vertical sliding rail 52 is extended parallel to the vertical direction, a sliding guide groove 521 is formed on a surface of the vertical sliding rail 52 facing the sliding block 6, the sliding guide groove 521 is vertically disposed and extends from the top end to the bottom end of the body of the vertical sliding rail 52, and the sliding block 6 is cooperatively mounted in the sliding guide groove 521 and can slide up and down in a reciprocating manner.

Further, the sliding block 6 has a rectangular block shape, the sliding guide 521 has a vertical square groove shape, and the shape of the sliding guide 521 is adapted to the shape of the sliding block 6.

With continued reference to fig. 1, the driving pin 7 has a driving pin positioning plate 71, a driving pin thread section 72 and a driving pin locking shaft 73; the driving pin thread section 72 and the driving pin locking shaft 73 are respectively formed at the front and rear side positions of the driving pin positioning plate 71, and the driving pin thread section 72 and the driving pin locking shaft 73 are both extended along the horizontal direction; the slider 6 is further provided with a slider locking hole 61, the shape of the slider locking hole 61 is matched with the driving pin locking shaft 73, and the driving pin locking shaft 73 is matched and penetrated in the slider locking hole 61 and is connected with the slider 6 body, so that the matching connection of the driving pin 7 and the slider 6 is realized.

Further, the swing arm 8 has a front swing shaft locking cylinder 81 and a swing arm lower sleeve 82; the swing rocker lower sleeve 82 is integrally formed at a lower position of the front swing shaft locking cylinder 81, a swing rocker lower sleeve threaded hole 821 is further formed in the swing rocker lower sleeve 82, and the transmission pin threaded section 72 of the transmission pin 7 is inserted into the swing rocker lower sleeve threaded hole 821 and is in threaded fit with the swing rocker lower sleeve threaded hole 821, so that the fixed connection of the transmission pin 7 and the swing rocker lower sleeve 82 is realized.

Further, the front swing shaft locking cylinder 81 is disposed horizontally in parallel to the horizontal direction, and the front swing shaft 21 is disposed to extend from the rear portion of the front head 2 body toward the rear portion, and the front swing shaft locking cylinder 81 is fitted over the shaft body of the front swing shaft 21 and is fixedly connected thereto, thereby realizing the fitting connection between the swing arm 8 and the front swing shaft 21.

In the present embodiment, a rear nose platform 12 is mounted on the front top end of the rear nose 1, and the rear nose platform 12 is extended toward the front in the horizontal direction; the lifting cylinder 3 is positioned and installed at the front end part of the rear machine head platform 12, the lifting cylinder 3 is provided with a piston rod 31 arranged at the lower part of the cylinder body, the piston rod 31 is arranged in a downward extending way along the vertical direction and can reciprocate up and down, the lifting cylinder 3 is in transmission connection with a pressure control pedal at the lower part of the case sewing machine, and a worker can control the lifting of the piston rod 31 of the lifting cylinder 3 through the pedal pressure control pedal, so that the up-down lifting movement of the front machine head 2 is realized; and a front nose matching sleeve seat 22 is also arranged at the top end of the front nose 2, and the piston rod 31 is matched and penetrated in the front nose matching sleeve seat 22, so that the piston rod 31 can drive the front nose 2 and the needle assembly 4 to move up and down.

Preferably, a front nose accommodating cavity 23 is formed at the front position of the front nose 2, and the needle assembly 4 is arranged in the front nose accommodating cavity 23 and protrudes downwards; the needle assembly 4 comprises a needle frame 41, a needle body 42 and an inner pressure foot 43, wherein the needle frame 41 is mounted on the body of the front machine head 2, the inner pressure foot 43 is cooperatively mounted at the bottom position of the needle frame 41, the inner pressure foot 43 is used for pressing the surface of the case and guiding the sewing material, the needle body 42 is penetrated in the needle frame 41, and the needle body 42 can reciprocate up and down and pass through the inner pressure foot 43 to sew the case.

Referring to fig. 1, the present inventors briefly describe the working principle of the technical solution provided by the present utility model: when the case needs to be sewn, firstly, a worker steps on the foot plate to enable the lifting cylinder 3 to work and control the front machine head 2 to lift, the front machine head 2 moves upwards, then the case is sleeved on the lower needle plate of the machine head, and then the worker releases the foot plate, so that the lifting cylinder 3 works and controls the front machine head 2 to move downwards to fall back, and at the moment, the inner presser foot 43 presses the edge of the case; the staff tramples the foot plate again to enable the case sewing machine to run integrally, the rear swinging shaft 11 of the rear machine head 1 swings, the swinging slide rail piece 5 fixedly sleeved on the rear swinging shaft 11 follows, then the swinging slide rail piece 5 drives the slide block 6, the transmission pin 7 and the swinging rocker arm 8 to swing together with the front swinging shaft 11, finally the needle assembly 4 is driven to swing, and the needle frame assembly 4 is enabled to make sewing action on the case; after the sewing operation is completed, the worker further steps on the foot plate to control the lifting cylinder 3 and realize the lifting action of the upper machine head 1, the sliding block 6 slides upwards in the sliding guide groove 521, the needle frame and the front machine head 2 keep relatively fixed positions in the process, the joint is free from looseness, the worker can take out the sewn case, the foot plate is loosened, the front machine head 2 falls back and resets under the driving of the lifting cylinder 3, the sliding block 6 slides downwards in the sliding guide groove 521 to the original position, and the needle frame assembly 4 also moves to the original bottom position, so that the whole sewing work flow is completed.

In summary, the technical scheme provided by the utility model overcomes the defects in the prior art, successfully completes the task of the utility model, and faithfully honors the technical effects carried by the applicant in the technical effect column above.

Claims (8)

1. The needle frame swing transmission mechanism for the case sewing machine comprises a rear machine head (1) and a front machine head (2), wherein the front machine head (2) is arranged at the front position of the rear machine head (1), the top of the front part of the rear machine head (1) is also provided with a lifting cylinder (3), the front machine head (2) can reciprocate up and down under the driving of the lifting cylinder (3), the front position of the front machine head (2) is also provided with a needle assembly (4) for sewing the case, a swinging rear swing shaft (11) is arranged at the front part near-bottom end part of the rear machine head (1), and a front swing shaft (21) is arranged at the rear part near-bottom end part of the front machine head (2); the method is characterized in that: the needle frame swing transmission mechanism comprises a swing sliding rail piece (5), a sliding block (6), a transmission pin (7) and a swing rocker arm (8), wherein the swing sliding rail piece (5), the sliding block (6), the transmission pin (7) and the swing rocker arm (8) are arranged between the rear machine head (1) and the front machine head (2), the rear part of the swing sliding rail piece (5) is connected with the rear swing shaft (11) in a matched mode, the sliding block (6) is slidingly arranged in the front part of the swing sliding rail piece (5) and can slide up and down in a reciprocating mode, the swing rocker arm (8) is connected with the front swing shaft (21) in a matched mode, and the transmission pin (7) is arranged between the sliding block (6) and the swing rocker arm (8) and is connected with the sliding block in a matched mode.

2. A needle holder swing transmission for a case sewing machine according to claim 1, wherein: the swinging slide rail piece (5) is provided with a cylindrical back swing shaft locking cylinder (51) and a vertical slide rail (52); the rear swing shaft locking cylinder (51) is transversely arranged in a state parallel to the horizontal direction, and the rear swing shaft locking cylinder (51) is sleeved on the shaft body of the rear swing shaft (11) and is fixedly connected with the shaft body; the vertical sliding rail (52) is integrally formed at the end part of the rear swing shaft locking cylinder (51) far away from the rear swing shaft (11), the vertical sliding rail (52) is arranged in an extending mode parallel to the vertical direction, a sliding guide groove (521) is formed in the surface of one side of the vertical sliding rail (52) facing the sliding block (6), the sliding guide groove (521) is vertically arranged and extends from the top end to the bottom end of the vertical sliding rail (52) body, and the sliding block (6) is mounted in the sliding guide groove (521) in a matched mode and can slide up and down in the sliding guide groove.

3. A needle holder swing transmission for a case sewing machine according to claim 2, wherein: the sliding block (6) is in a rectangular block shape, the sliding guide groove (521) is in a vertical square groove shape, and the shape of the sliding guide groove (521) is matched with the shape of the sliding block (6).

4. A needle holder swing transmission for a case sewing machine according to claim 1, wherein: the driving pin (7) is provided with a driving pin positioning plate (71), a driving pin thread section (72) and a driving pin locking shaft (73); the transmission pin thread section (72) and the transmission pin locking shaft (73) are respectively formed at the front side and the rear side of the transmission pin positioning plate (71), and the transmission pin thread section (72) and the transmission pin locking shaft (73) are both arranged in an extending manner along the horizontal direction; the sliding block (6) is also provided with a sliding block locking hole (61), the shape of the sliding block locking hole (61) is matched with that of the transmission pin locking shaft (73), and the transmission pin locking shaft (73) is matched and penetrated in the sliding block locking hole (61) and is connected with the sliding block (6) body, so that the matched connection of the transmission pin (7) and the sliding block (6) is realized.

5. A needle holder swing transmission for a case sewing machine according to claim 4, wherein: the swing rocker arm (8) is provided with a front swing shaft locking cylinder (81) and a swing rocker arm lower sleeve (82); the swing rocker lower sleeve (82) is integrally formed at the lower position of the front swing shaft locking cylinder (81), a swing rocker lower sleeve threaded hole (821) is further formed in the swing rocker lower sleeve (82), and a transmission pin threaded section (72) of the transmission pin (7) is penetrated in the swing rocker lower sleeve threaded hole (821) and is in threaded fit with the swing rocker lower sleeve threaded hole, so that the fixed connection of the transmission pin (7) and the swing rocker lower sleeve (82) is realized.

6. A needle holder swing transmission for a case sewing machine according to claim 5, wherein: the front swing shaft locking cylinder (81) is transversely arranged in a state parallel to the horizontal direction, the front swing shaft (21) extends from the rear part of the front machine head (2) towards the rear part, and the front swing shaft locking cylinder (81) is sleeved on the shaft body of the front swing shaft (21) and is fixedly connected with the shaft body, so that the swing rocker (8) is matched and connected with the front swing shaft (21).

7. A needle holder swing transmission for a case sewing machine according to claim 1, wherein: a rear nose platform (12) is arranged at the top end of the front part of the rear nose (1), and the rear nose platform (12) extends towards the front part along the horizontal direction; the lifting cylinder (3) is positioned and installed at the front end part position of the rear machine head platform (12), the lifting cylinder (3) is provided with a piston rod (31) arranged at the lower part of the cylinder body, the piston rod (31) extends downwards along the vertical direction and can reciprocate up and down, the top end part of the front machine head (2) is also provided with a front machine head matching sleeve seat (22), and the piston rod (31) is matched and arranged in the front machine head matching sleeve seat (22) in a penetrating way, so that the piston rod (31) can drive the front machine head (2) and the machine needle assembly (4) to move up and down.

8. A needle holder swing transmission for a case sewing machine according to claim 1, wherein: a front machine head accommodating cavity (23) is formed in the front position of the front machine head (2), and the machine needle assembly (4) is arranged in the front machine head accommodating cavity (23) and protrudes downwards; the needle assembly (4) comprises a needle frame (41), a needle body (42) and an inner pressure foot (43), wherein the needle frame (41) is arranged on the body of the front machine head (2), the inner pressure foot (43) is arranged at the bottom of the needle frame (41) in a matching way, the inner pressure foot (43) is used for pressing the surface of a case, the needle body (42) is arranged in the needle frame (41) in a penetrating way, and the needle body (42) can reciprocate up and down and pass through the inner pressure foot (43) to sew the case.