A needle guard mechanism for a sewing machine
Patent Information
- Application Number
- CN202522106139.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2026-10-16
- Estimated Expiration
- 2035-09-29
AI Technical Summary
这种设计导致机器在使用过程中出现诸多问题：调整针码疏密时，后护针器无法正常发挥功能；送布传动结构出现磨损或松动时，护针的动作时序难以精准匹配，护针部件的运动易受送布节奏干扰，会直接影响后护针的准确性，进而造成跳线、断线、断针等现象，严重影响了生产效率和产品质量
[0020]1. This utility model, through the establishment of an independent dedicated transmission system, consisting of a power input device, a linkage transmission assembly, and a needle guard swing rod, enables the movement of the needle guard mechanism to be completely independent of the fabric feeding mechanism. This ensures the precise and stable timing of the needle guard's movement, unaffected by needle length adjustments or wear on the fabric feeding mechanism. It can accurately and promptly contact and support the needle during the critical stage of the bobbin hook's hooking action, preventing excessive needle bending due to fabric obstruction. This effectively avoids excessive collision and wear between the bobbin hook tip and the needle, as well as skipped stitches, thread breaks, and needle breakage, greatly improving sewing quality and production efficiency while reducing maintenance costs.
Smart Images
Figure CN224858580U_ABST
Abstract
Description
[Technical Field]
[0001] This utility model relates to a needle protection mechanism for a sewing machine. [Background Technology]
[0002] In the sewing machine industry, the articulated arm four-needle six-thread stitching machine is specifically designed for sewing processes requiring a "tube-like" effect, such as sleeve and trouser hem shaping and stitching. Traditional four-needle six-thread machines have a flawed structural design: the rear needle guard function is attached to and dependent on the feed mechanism, meaning the needle guard function is usually integrated into the feed mechanism's feed dog, with the needle guard's movement linked to the feed action. This design leads to numerous problems during machine use: when adjusting stitch density, the rear needle guard cannot function properly; when the feed mechanism is worn or loose, the timing of the needle guard's movement is difficult to match precisely, and the movement of the needle guard component is easily affected by the feed rhythm, directly impacting the accuracy of the rear needle guard, resulting in skipped stitches, thread breaks, and needle breaks, severely affecting production efficiency and product quality.
[0003] Therefore, this utility model was created based on the above-mentioned shortcomings. [Utility Model Content]
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a needle protection mechanism for a sewing machine that is structurally independent and has precise and reliable operation.
[0005] This utility model is achieved through the following technical solution:
[0006] A needle protection mechanism for a sewing machine, characterized in that it includes: a needle protector frame;
[0007] A needle protector, which is attached to one end of the needle protector holder 1 and located on the side of the sewing machine needle and bobbin hook;
[0008] A power input device for obtaining rotational power from the power shaft of a sewing machine;
[0009] A linkage drive assembly, which is connected to the power input device to transmit power;
[0010] The needle protector swing arm is hinged at one end to the sewing machine body. The output end of the linkage transmission assembly is hinged to the other end of the needle protector swing arm, causing the needle protector swing arm to swing back and forth. The needle protector frame is connected to the needle protector swing arm and is driven by the needle protector swing arm to reciprocate back and forth. This causes the needle protector to move forward to a preparatory position away from the needle track when the sewing machine needle descends, or to move backward from the preparatory position to a position close to the needle when the sewing machine needle rises and the bobbin hook is hooking the thread.
[0011] The needle protection mechanism of the sewing machine described above is characterized in that: the power input device is an eccentric cam for the needle protection, which is mounted on the power shaft of the sewing machine.
[0012] The needle protection mechanism of the sewing machine as described above is characterized in that: the linkage transmission assembly includes a first needle protection link connected at one end to the eccentric cam of the needle protection and driven by the eccentric cam to reciprocate; a first needle protection crank hinged at one end to the other end of the first needle protection link and driven by the first needle protection link to swing back and forth; a needle protection swing shaft connected at one end to the other end of the first needle protection crank and driven by the first needle protection crank to rotate clockwise or counterclockwise; a second needle protection crank connected at one end to the other end of the needle protection swing shaft and driven by the needle protection swing shaft to swing; and a second needle protection link hinged between the second needle protection crank and the needle protection swing shaft to drive the needle protection swing shaft to reciprocate around its sewing machine body.
[0013] The needle protection mechanism of the sewing machine as described above is characterized in that: the needle protection frame is hinged to the middle of the needle protection swing rod via a connecting rod.
[0014] The needle protection mechanism of the sewing machine as described above is characterized in that: two connecting rods are provided and symmetrically arranged on both sides of the needle protection swing rod and the needle protection frame.
[0015] The needle protection mechanism of the sewing machine as described above is characterized in that: the needle protection frame is provided with an upwardly extending column, the needle protector is provided on the column and can move up and down relative to the needle protection frame and rotate relative to the column, and the needle protector or the column is provided with a locking device that locks the needle protector on the column after the needle protector moves up and down or rotates.
[0016] The needle protection mechanism of the sewing machine as described above is characterized in that: the needle protector is provided with a first vertical mounting hole for fitting onto the column and a first screw hole communicating with the first vertical mounting hole, and the locking device is a screw that passes through the first screw hole and whose one end can extend into the first vertical mounting hole and abut against the side wall of the column.
[0017] The needle guard mechanism of the sewing machine as described above is characterized in that: the needle guard frame is provided with a second vertical mounting hole for the lower end of the column to be inserted, a second screw hole communicating with the second vertical mounting hole, and a locking screw that passes through the second screw hole and whose one end can extend into the second vertical mounting hole and abut against the side wall of the column.
[0018] The needle protection mechanism of the sewing machine as described above is characterized in that: a wear-resistant layer is provided on the contact end of the needle protector that is in contact with the needle.
[0019] Compared with the prior art, the present invention has the following advantages:
[0020] 1. This utility model, through the establishment of an independent dedicated transmission system, consisting of a power input device, a linkage transmission assembly, and a needle guard swing rod, enables the movement of the needle guard mechanism to be completely independent of the fabric feeding mechanism. This ensures the precise and stable timing of the needle guard's movement, unaffected by needle length adjustments or wear on the fabric feeding mechanism. It can accurately and promptly contact and support the needle during the critical stage of the bobbin hook's hooking action, preventing excessive needle bending due to fabric obstruction. This effectively avoids excessive collision and wear between the bobbin hook tip and the needle, as well as skipped stitches, thread breaks, and needle breakage, greatly improving sewing quality and production efficiency while reducing maintenance costs.
[0021] 2. This utility model uses a column and an adjustable structure to enable the needle protector to move up and down and rotate to adjust the angle. It can accurately correct angle deviations or slight height deviations and can adapt to the sewing needs of different fabrics and needle models without replacing parts. It is easy to operate and reduces debugging costs.
[0022] 3. In this utility model, the wear-resistant layer design of the needle protector significantly reduces frictional wear during long-term use, extends the component replacement cycle, and reduces maintenance costs. [Attached Image Description]
[0023] Figure 1 This is a perspective view of the present invention;
[0024] Figure 2 This is a partial exploded view of the present invention.
Detailed Implementation Methods
[0025] The present invention will be further described below with reference to the accompanying drawings:
[0026] like Figure 1-2 As shown, a needle protection mechanism for a sewing machine, the core of which is a transmission system independent of the fabric feeding mechanism, includes: a needle protector frame 1; a needle protector 2, which is connected to one end of the needle protector frame 1 and located on the side of the sewing machine's needle and bobbin hook; a power input device 3, used to obtain rotational power from the sewing machine's power shaft; a linkage transmission assembly 4, which is connected to the power input device 3 to transmit power; and a needle protector swing arm 5, one end of which is hinged to the sewing machine body, the output end of the linkage transmission assembly 4 being connected to the needle protector swing arm. The other end of the lever 5 is hinged to drive the needle protector swing lever 5 to swing back and forth. The needle protector frame 1 is connected to the needle protector swing lever 5 and is driven by the needle protector swing lever 5 to move back and forth, so that the needle protector 2 moves forward to a preparatory position away from the needle track before the sewing machine needle is about to descend. This preparatory position is the farthest position of the needle protector 2 from the needle, or the needle protector 2 moves backward from the preparatory position to the side of the needle when the sewing machine needle rises and the bottom thread hook is hooking the thread, that is, the needle protector 2 moves to the position closest to the needle.
[0027] Specifically, the power input device 3 is a needle protection eccentric cam mounted on the sewing machine's power shaft, which rotates synchronously with the power shaft. When the power shaft rotates, the eccentric structure of the needle protection eccentric cam pushes the first needle protection link 41 in contact with it to perform a reciprocating linear motion.
[0028] The linkage transmission assembly 4 includes a first needle connecting rod 41, one end of which is connected to the eccentric cam of the needle and driven by the eccentric cam to reciprocate; a first needle crank 42, one end of which is hinged to the other end of the first needle connecting rod 41 and driven by the first needle connecting rod 41 to swing back and forth; a needle swing shaft 43, one end of which is connected to the other end of the first needle crank 42 and driven by the first needle crank 42 to rotate clockwise or counterclockwise; a second needle crank 44, one end of which is connected to the other end of the needle swing shaft 43 and driven by the needle swing shaft 43 to swing; and a second needle connecting rod 45, which is hinged between the second needle crank 44 and the needle swing rod 5 to drive the needle swing rod 5 to swing back and forth around its sewing machine body. Specifically, the front end of the first connecting rod 41 of the needle protector is mounted on the eccentric cam of the needle protector via a bushing, and the bushing contacts the wheel surface of the eccentric cam. The rear end of the first connecting rod 41 is hinged to the upper end of the first crank 42 of the needle protector via a pin. The needle swing shaft 43 is parallel to the power shaft of the sewing machine, and the lower end of the first crank 42 is fixedly connected to one end of the swing shaft 43. The swing shaft 43 reciprocates clockwise / counterclockwise with the reciprocating motion of the first connecting rod 41. The upper end of the second crank 44 is fixedly connected to the other end of the swing shaft 43, and the swing shaft 43 drives the second crank 44 to swing synchronously. The front end of the second connecting rod 45 is hinged to the lower end of the second crank 44 via a pin. The lower end of the swing rod 5 is hinged to a part of the sewing machine body (not shown in the figure) via a pin, forming its swing fulcrum. The rear end of the second connecting rod 45 of the needle is hinged to the upper end of the needle pendulum 5 via a pin, thereby transmitting power to the needle pendulum 5 and causing it to swing.
[0029] Specifically, the needle holder 1 is hinged to the middle of the needle holder lever 5 via the connecting rod 6.
[0030] Specifically, there are two connecting rods 6 arranged symmetrically on both sides of the needle guarding rod 5 and the needle guarding frame 1 to enhance transmission stability and prevent the needle guarding frame 1 from tilting during movement.
[0031] The needle holder 1 has an upwardly extending column 9. The needle protector 2 is mounted on the column 9 and can move up and down relative to the needle holder 1 and rotate relative to the column 9. The needle protector 2 or the column 9 is equipped with a locking device 10 that locks the needle protector 2 onto the column 9 after it moves up and down or rotates. This utility model, through the column and adjustable structure, enables the needle protector to move up and down and rotate to adjust its angle. It can accurately correct angle deviations or minor height deviations, and can adapt to the sewing needs of different fabrics and needle types without replacing parts. It is easy to operate and reduces debugging costs.
[0032] Specifically, the needle protector 2 is provided with a first vertical mounting hole 21 for fitting onto the column 9 and a first screw hole 22 communicating with the first vertical mounting hole 21. The locking device 10 is a screw that passes through the first screw hole 22 and whose end can extend into the first vertical mounting hole 21 to abut against the side wall of the column 9. Loosen the screw and slide the needle protector 2 up and down along the height of the column 9 until its contact height with the needle matches, then tighten it; or loosen the screw, rotate the needle protector 2 around the column 9 to adjust its contact angle with the needle (such as correcting a deviation of 1°-2°) to ensure that the needle protector 2 can accurately fit the side of the needle, then tighten it.
[0033] Specifically, the needle holder 1 is provided with a second vertical mounting hole 11 for inserting the lower end of the column 9, a second screw hole 12 communicating with the second vertical mounting hole 11, and a locking screw 20 that passes through the second screw hole 12 and has one end that can extend into the second vertical mounting hole 11 and abut against the side wall of the column 9. Loosen the locking screw 20, move the column 9 up and down to the target height, and then tighten the locking screw 20 to lock the column.
[0034] Specifically, the contact end of the needle protector 2 that comes into contact with the needle is provided with a wear-resistant layer. The wear-resistant layer is a welded wear-resistant alloy steel layer or an electroplated wear-resistant material layer, such as a chromium plating layer or a titanium plating layer, which can reduce frictional wear between the needle protector and the needle and extend its service life.
[0035] The working principle and operation process of this utility model are as follows:
[0036] The sewing machine's power shaft 8 rotates, causing the eccentric cam of the needle protector to rotate, which in turn drives the needle protector swing arm 5 to swing back and forth around its lower hinge point via the aforementioned linkage transmission assembly 4. The swing of the needle protector swing arm 5 drives the needle protector frame 1 and the needle protector 2 to reciprocate back and forth through two connecting rods 6.
[0037] When the needle 7 begins to descend from its highest point, the needle guard 2 moves toward the operator under the drive of the linkage transmission assembly 4. When the needle tip reaches its lowest point, the needle guard 2 reaches the position closest to the needle, and from this point on, it begins to switch to move in the opposite direction.
[0038] When the needle 7 rises approximately 2mm from its lowest point, and the tip of the bobbin hook begins to catch the loop behind the needle, the needle protector 2, driven by the transmission system, moves backward from its preparatory position, precisely and promptly abutting against the back of the needle. During this process, even if the needle slightly bends due to fabric resistance, the needle protector 2 provides support, limiting the degree of bending and returning the misaligned needle to its correct position. The needle protector 2 pauses briefly throughout the bobbin hook's hooking process to ensure the tip of the bobbin hook can smoothly catch the loop without violently colliding with the needle.
[0039] Once the bottom line hook has completed hooking and moved past the rightmost needle, the needle protector 2 begins to move forward again, away from the needle, that is, away from the operator. When the needle rises to its highest position, the needle protector 2 also moves to the position furthest from the operator and pauses for a moment. From this point, it switches to move in the opposite direction and waits for the next work cycle.
[0040] This process is repeated continuously, allowing the needle-protecting action to be completed independently and precisely.
Claims
1. A needle protection mechanism for a sewing machine, characterized in that, include: Needle holder (1); Needle protector (2), which is connected to one end of needle protector (1) and located on the side of the sewing machine needle and bottom hook; The power input device (3) is used to obtain rotational power from the power shaft of the sewing machine; Linkage drive assembly (4), which is connected to the power input device (3) to transmit power; The needle protector swing arm (5) is hinged at one end to the sewing machine body. The output end of the linkage transmission assembly (4) is hinged to the other end of the needle protector swing arm (5) to drive the needle protector swing arm (5) to swing back and forth. The needle protector frame (1) is connected to the needle protector swing arm (5) and is driven by the needle protector swing arm (5) to move back and forth, so that the needle protector (2) moves forward to a preparatory position away from the needle track when the sewing machine needle descends, or moves backward from the preparatory position to a position close to the needle when the sewing machine needle rises and the bottom thread hook hooks the thread.
2. The needle guard mechanism of the sewing machine according to claim 1, characterized in that: The power input device (3) is a needle protection eccentric cam installed on the power shaft of the sewing machine.
3. The needle guard mechanism of the sewing machine according to claim 2, characterized in that: The linkage transmission assembly (4) includes a first needle connecting rod (41) that is connected to the eccentric cam of the needle and reciprocated by the eccentric cam of the needle; a first needle crank (42) that is hinged to the other end of the first needle connecting rod (41) and oscillates back and forth by the first needle connecting rod (41); a needle swing shaft (43) that is connected to the other end of the first needle crank (42) and rotates clockwise or counterclockwise by the first needle crank (42); a second needle crank (44) that is connected to the other end of the needle swing shaft (43) and oscillates by the needle swing shaft (43); and a second needle connecting rod (45) that is hinged between the second needle crank (44) and the needle swing rod (5) to drive the needle swing rod (5) to oscillate back and forth around its sewing machine body.
4. The needle guard mechanism of the sewing machine according to claim 3, characterized in that: The needle holder (1) is hinged to the middle of the needle holder swing rod (5) via a connecting rod (6).
5. The needle guard mechanism of the sewing machine according to claim 4, characterized in that: The connecting rod (6) is provided in two and symmetrically arranged on both sides of the needle guard rod (5) and the needle guard frame (1).
6. The needle guard mechanism of the sewing machine according to claim 1, characterized in that: The needle holder (1) is provided with an upwardly extending column (9), and the needle protector (2) is provided on the column (9) and can move up and down relative to the needle holder (1) and rotate relative to the column (9). The needle protector (2) or the column (9) is provided with a locking device (10) that locks the needle protector (2) on the column (9) after the needle protector (2) moves up and down or rotates.
7. The needle guard mechanism of the sewing machine according to claim 6, characterized in that: The needle protector (2) is provided with a first vertical mounting hole (21) for fitting onto the column (9) and a first screw hole (22) communicating with the first vertical mounting hole (21). The locking device (10) is a screw that passes through the first screw hole (22) and one end can extend into the first vertical mounting hole (21) and abut against the side wall of the column (9).
8. The needle guard mechanism of the sewing machine according to claim 6, characterized in that: The needle holder (1) is provided with a second vertical mounting hole (11) for the lower end of the column (9) to be inserted, a second screw hole (12) communicating with the second vertical mounting hole (11), and a locking screw (20) that passes through the second screw hole (12) and has one end that can extend into the second vertical mounting hole (11) and abut against the side wall of the column (9).
9. The needle guard mechanism of the sewing machine according to claim 1, characterized in that: The needle protector (2) has a wear-resistant layer on the contact end that is in contact with the needle.