A medium pressure foot height adjusting mechanism and sewing machine

Abstract

The utility model provides a kind of middle pressure foot height adjusting mechanism, including driving motor and pivot, pivot is rotatably mounted with lift pressure lever and connecting seat respectively, one end of lift pressure lever is transmission connection with the output shaft of driving motor, the other end is equipped with the first abutting surface for with the lower surface of connecting seat abutting, connecting seat is transmission connection with middle pressure foot;Lift pressure lever rotates around pivot under the drive of driving motor, connecting seat rotates around pivot synchronously, so that middle pressure foot rises or falls.The utility model further provides a kind of sewing machine, including aforementioned middle pressure foot height adjusting mechanism.The utility model provides the structure of middle pressure foot height adjusting mechanism Simple and compact, and have shorter transmission distance, by controlling the rotation angle of driving motor output shaft can accurately, in time adjust the up-down position of middle pressure foot.

Description

Technical Field

[0001] This utility model relates to the field of sewing machine technology, and in particular to a medium presser foot height adjustment mechanism and a sewing machine. Background Technology

[0002] During the operation of a sewing machine, when the needle pierces the fabric, the presser foot descends and presses the fabric tightly to fix it in place so as to form a sewing thread loop; when the needle rises, the presser foot rises with it and leaves the fabric so that the fabric feeding mechanism can feed the fabric.

[0003] Existing presser foot follow-up and height adjustment mechanisms can generally be divided into two categories. One is the electronic presser foot, where a single motor directly drives the presser foot's follow-up and height adjustment. The other is the mechanical presser foot, where a main shaft motor drives the upper shaft to rotate, and the upper shaft, through a mechanical transmission mechanism, achieves the presser foot's follow-up. A separate motor controls the presser foot's height adjustment. Each of these technologies has its advantages and disadvantages in practical applications. The electronic presser foot technology is limited by the synchronization problem of the sewing machine at high speeds due to the direct motor-driven follow-up, making it difficult to apply at even higher speeds. The mechanical presser foot technology, driven directly by the upper shaft, has an advantage in synchronization and lower requirements for the motor.

[0004] Traditional mechanical presser foot technology mostly involves adjusting the height of the presser foot via a series of mechanisms on the right side of the machine head. This results in a relatively long overall transmission distance, which can easily lead to inaccurate control of the presser foot height. Utility Model Content

[0005] To address the aforementioned shortcomings, the purpose of this utility model is to provide a medium pressure foot height adjustment mechanism.

[0006] This utility model provides a height adjustment mechanism for a middle presser foot, including a drive motor and a rotating shaft both installed in a sewing machine. A lifting lever and a connecting seat are rotatably mounted on the rotating shaft. One end of the lifting lever is driven to the output shaft of the drive motor, and the other end is provided with a first abutting surface for abutting against the lower surface of the connecting seat. The connecting seat is driven to the middle presser foot. When the lifting lever rotates around the rotating shaft under the drive of the drive motor, the connecting seat rotates synchronously around the rotating shaft, thereby raising or lowering the middle presser foot.

[0007] Preferably, it also includes a limiting member disposed above the lifting lever, wherein when the lifting lever abuts against the limiting member, the middle pressure foot is located at the lower stop point of its lifting stroke.

[0008] Preferably, the sewing machine also includes a mounting base, on which the drive motor and the limiting member are both mounted.

[0009] Preferably, it also includes a position sensor connected to the drive motor, the position sensor being used to detect whether the output shaft has rotated to a preset angle.

[0010] Preferably, it further includes a sensor disposed on the output shaft, the position sensor being used to detect whether the sensor has moved into position.

[0011] Preferably, a lifting crank is provided on the output shaft, and one end of the lifting lever is rotatably connected to the end of the lifting crank via a lifting connecting rod.

[0012] This utility model also provides a sewing machine, including the aforementioned presser foot height adjustment mechanism.

[0013] Preferably, it further includes an upper shaft rotatably disposed in the sewing machine, the upper shaft being drivenly connected to the middle presser foot via a follower mechanism; the connecting seat is rotatably connected to the follower mechanism.

[0014] Preferably, the follower mechanism includes an eccentric wheel mounted on the upper shaft, a pressure arm shaft, a first crank mounted at one end of the pressure arm shaft, a second crank mounted at the other end of the pressure arm shaft, an eccentric wheel connecting rod for connecting the first crank and the eccentric wheel, a connecting crank, and a swing connecting rod for connecting the second crank and the connecting crank. The connecting crank is L-shaped, with its upper end connected to the swing connecting rod, its middle part rotatably engaged with the connecting seat, and its left end rotatably connected to the pressure foot drive rod. The pressure foot drive rod is connected to the middle pressure foot through the pressure foot rod.

[0015] Preferably, it further includes a guide rod extending vertically, the presser foot rod and the guide rod are slidably coupled coaxially, a spring and a spring sleeve are respectively sleeved on the guide rod, the upper end of the spring abuts against the upper end of the guide rod, the lower end abuts against the spring sleeve, and the spring sleeve abuts against the boss provided on the connecting seat.

[0016] The height adjustment mechanism for the middle presser foot provided by this utility model has a simple and compact structure and a short transmission distance. The vertical position of the middle presser foot can be accurately and timely adjusted by controlling the rotation angle of the output shaft of the drive motor. When the bottom of the middle presser foot encounters a sudden change in fabric height, such as a sudden change in the fabric height, the lifting lever can be separated from the connecting seat, and the operation of the drive motor is not affected, preventing the phenomenon of drive motor stall alarm. Attached Figure Description

[0017] Figure 1 and Figure 2 These are perspective views of the pressure foot height adjustment mechanism in this utility model from different viewpoints;

[0018] Figure 3 This is the main view of the lifting and pressing lever;

[0019] Figure 4 This is a schematic diagram showing the relative positions of the sensing element and the position sensor when the pressure foot is at the top dead center of its stroke.

[0020] Figure 5 It is a schematic diagram of the connection structure of the upper shaft, follower mechanism, connecting seat, spring, pressure foot rod and middle pressure foot;

[0021] Figure 6 This is a schematic diagram of the connector.

[0022] Component designation explanation:

[0023] 1 Mounting base

[0024] 2. Drive motor

[0025] 3 supports

[0026] 4 Limiting components

[0027] 5. Lift and press the crank.

[0028] 6. Lifting and pressing the connecting rod

[0029] 7 Position Sensors

[0030] 8. Sensors

[0031] 9. Lifting and pressing the lever

[0032] 91 First contact surface

[0033] 92 Second contact surface

[0034] 93 Connecting hole

[0035] 10-spindle

[0036] 11. Follow-up mechanism

[0037] 111 Connector

[0038] 111a First mounting hole

[0039] 111b Second mounting hole

[0040] 111c Boss

[0041] 112 Connecting crank

[0042] 113 Eccentric Wheel

[0043] 114 Eccentric wheel connecting rod

[0044] 115 Pressure Arm Shaft

[0045] 116 First Crank

[0046] 117 Second Crank

[0047] 118 Swing Link

[0048] 12 medium presser feet

[0049] 13. Presser foot bar

[0050] 131 Presser foot drive lever

[0051] 14 Upper Axle

[0052] 15 Springs Detailed Implementation

[0053] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. These embodiments are only used to illustrate this utility model and are not intended to limit it.

[0054] In the description of this utility model, it should be noted that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0056] Figure 4 The diagram shows the relative positions of the sensing element and the position sensor when the pressure foot is at the top dead center of its stroke; in the following description, ... Figure 4 The attached diagram serves as a reference for direction. Figure 4 In the diagram, the direction perpendicular to the view paper and facing outwards is the forward direction, the direction perpendicular to the view paper and facing inwards is the backward direction, the direction upwards along the view paper is the upward direction, the direction downwards along the view paper is the downward direction, the direction to the right along the view paper is the right direction, and the direction to the left along the view paper is the left direction.

[0057] like Figures 1-3As shown, this utility model provides a medium presser foot height adjustment mechanism, which includes a mounting base 1 disposed in a sewing machine, a drive motor 2 disposed on the mounting base 1, and a rotating shaft 10 fixedly installed in the sewing machine. A lifting lever 9 and a connecting seat 111 are rotatably mounted on the rotating shaft 10 extending in the front-rear direction. The lifting lever 9 has a connecting hole 93 in its middle for rotatable connection with the rotating shaft 10, its left end is connected to the output shaft 21 of the drive motor 2, and its right end has a first abutting surface 91 for abutting against the lower surface of the connecting seat 111; the connecting seat 111 is connected to the medium presser foot 12.

[0058] When the lifting lever 9 rotates counterclockwise around the shaft 10 under the drive of the drive motor 2, the right end of the lifting lever 9 swings upward and pushes the connecting seat 111 to rotate counterclockwise around the shaft 10 synchronously through the first abutment surface 91, thereby raising the middle pressure foot 12. When the lifting lever 9 rotates clockwise around the shaft 10 under the drive of the drive motor 2, the right end of the lifting lever 9 swings downward, and the connecting seat 111, after losing the support of the first abutment surface 91, will rotate clockwise around the shaft 10 synchronously under the action of gravity until it abuts against the first abutment surface 91. During this process, the middle pressure foot 12 descends. Since the rotation centers of the connecting seat 111 and the lifting lever 9 are coaxially arranged, there is no relative sliding between the first abutment surface 91 and the lower surface of the connecting seat 111, so no wear will occur between them. When the bottom of the middle presser foot 12 encounters resistance, the connecting seat 111 stops rotating, and the downward swing of the right end of the lifting lever 9 is unaffected, and the first contact surface 91 and the lower surface of the connecting seat 111 separate.

[0059] As can be seen from the above, the height adjustment mechanism for the middle presser foot provided by this utility model has a simple and compact structure and a short transmission distance. The vertical position of the middle presser foot can be accurately and timely adjusted by controlling the rotation angle of the output shaft of the drive motor. When the bottom of the middle presser foot encounters a sudden change in fabric height, such as a sudden change in the fabric height, the lifting lever can be separated from the connecting seat, and the operation of the drive motor is not affected, preventing the phenomenon of drive motor stall alarm.

[0060] like Figure 1 and Figure 2 As shown, the height adjustment mechanism for the middle pressure foot provided by this utility model also includes a bracket 3 and a position sensor 7 mounted on the mounting base 1. A limiting member 4 extending in the vertical direction is connected to the bracket 3. The limiting member 4 and the position sensor 7 are used to limit the lower and upper stops of the lifting stroke of the middle pressure foot 12, respectively.

[0061] like Figures 1-3As shown, the limiting member 4 is adjustable in height on the bracket 3 and is located above the lifting lever 9. Furthermore, the left end of the lifting lever 9 is provided with a second abutting surface 92 for contacting the limiting member 4. During the clockwise rotation of the lifting lever 9 around the pivot 10, the left end of the lifting lever 9 swings upward, while the right end swings downward; when the second abutting surface 92 contacts the lower end of the limiting member 4, the right end of the lifting lever 9 swings downward to its maximum angle, and the middle pressure foot 12 is located at the lower stop of its lifting stroke.

[0062] like Figure 1 , Figure 2 and Figure 4 As shown, the position sensor 7 is signal-connected to the drive motor 2 and is used to detect whether the output shaft 21 has rotated to the preset angle corresponding to the middle pressure foot 12 being at the upper stop of its lifting stroke. Specifically, a sensing element 8 is also provided on the output shaft 21, and the position sensor 7 is used to detect whether the sensing element 8 has moved into position. The position sensor 7 can be a photoelectric sensor. When the light emitted by the light source located on top of the position sensor 7 is blocked by the sensing element 8, it means that the sensing element 8 has moved into position and the output shaft 21 has rotated to the preset angle. At this time, the position sensor 7 outputs a signal to the drive motor 2, and the output shaft 21 of the drive motor 2 stops rotating.

[0063] In one specific embodiment of this utility model, a lifting crank 5 is also provided on the output shaft 21, and the left end of the lifting lever 9 is rotatably connected to the end of the lifting crank 5 through a lifting connecting rod 6. When the output shaft 21 drives the lifting crank 5 to rotate clockwise, the lifting lever 9 rotates counterclockwise around the rotating shaft 10, and the middle pressure foot 12 rises; when the output shaft 21 drives the lifting crank 5 to rotate counterclockwise, the lifting lever 9 rotates clockwise around the rotating shaft 10, and the middle pressure foot 12 falls. In this embodiment, the position sensor 7 is located on the left side of the output shaft 21. When the light emitted by the light source at the top of the position sensor 7 is blocked by the sensing element 8, it means that the output shaft 21 has rotated clockwise to a preset angle, at which time the middle pressure foot 12 is located at the upper dead point of its lifting stroke.

[0064] This utility model also provides a sewing machine, which includes the above-mentioned presser foot height adjustment mechanism.

[0065] like Figure 1 , Figure 2 and Figure 5As shown, the sewing machine also includes an upper shaft 14 rotatably mounted within the machine. The upper shaft 14 is connected to the middle presser foot 12 via a follower mechanism 11; the connecting seat 111 is rotatably connected to the follower mechanism 11. That is, the rotational movement of the upper shaft 14 can drive the middle presser foot 12 to rise and fall, achieving follow-up with the sewing machine needle. When the middle presser foot 12 is close to the fabric, it generates greater downward pressure, resulting in more aesthetically pleasing and stable stitches. Using a drive motor 2 to adjust the height of the middle presser foot 12 helps to dynamically adjust its height according to changes in fabric thickness.

[0066] Specifically, the follower mechanism includes an eccentric wheel 113 mounted on the upper shaft 14, a pressure arm shaft 115, a first crank 116 located at the rear end of the pressure arm shaft 115, a second crank 117 located at the front end of the pressure arm shaft 115, an eccentric wheel connecting rod 114 connecting the first crank 116 and the eccentric wheel 113, a connecting crank 112, and a swing connecting rod 118 connecting the second crank 117 and the connecting crank 112. The first crank 116 has an adjustment groove, and the end of the eccentric wheel connecting rod 114 furthest from the eccentric wheel 113 has a connecting shaft, which is slidably positioned in the adjustment groove. The connecting crank 112 is L-shaped, with its upper end connected to the right end of the swing connecting rod 118, its middle part rotatably engaged with the connecting seat 111, and its left end rotatably connected to the pressure foot drive rod 131. The pressure foot drive rod 131 is connected to the middle pressure foot 12 via the pressure foot rod 13. When the upper shaft 14 rotates, it drives the eccentric wheel 113 to rotate as well. Through the eccentric wheel connecting rod 114, the first crank 116, and the pressure arm shaft 115, the rotational motion of the upper shaft 14 is converted into the left-right swinging motion of the lower end of the second crank 117. Then, through the swing connecting rod 118, the left-right swinging motion of the lower end of the second crank 117 is converted into the left-right swinging motion of the upper end of the connecting crank 112. When the upper end of the connecting crank 112 swings left and right, the left end of the connecting crank 112 swings up and down, thereby driving the middle pressure foot 12 to move up and down.

[0067] like Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, the connecting seat 111 specifically includes a first mounting hole 111a located at its left end, and a second mounting hole 111b and a boss 111c located at its right end, wherein the second mounting hole 111b is located in front of the boss 111c. The first mounting hole 111a is rotatably mounted on the rotating shaft 10, and the second mounting hole 111b is rotatably engaged with the middle part of the connecting crank 112.

[0068] The sewing machine also includes vertically extending guide rods, with the presser foot 13 slidingly coaxially with the guide rods. A spring 15 and a spring sleeve are respectively fitted onto the guide rods. The upper end of the spring 15 abuts against a fixing cap located at the upper end of the guide rod, and the lower end of the spring 15 abuts against the spring sleeve. The spring sleeve abuts against the boss 111c of the connecting seat 111. The spring 15 applies a downward elastic force to the middle presser foot 12 through the connecting seat 111 and the connecting crank 112. When the torque output by the drive motor 2 is sufficiently large, the first abutment surface 91 applies sufficient upward thrust to the connecting seat 111, causing the connecting seat 111 to rotate counterclockwise against the elastic force of the spring 15, driving the left end of the connecting crank 112 upward, thereby lifting the middle presser foot 12.

[0069] In the sewing machine provided by this utility model, the synchronous movement between the presser foot 12 and the needle and shuttle is not changed by the setting of the presser foot height adjustment mechanism. The pressure of the presser foot 12 is provided by the spring 15. When the drive motor 2 stops working, the presser foot 12 can still maintain the pressed state and will not shake randomly.

[0070] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A height adjustment mechanism for a pressure foot, characterized in that, The sewing machine includes a drive motor (2) and a rotating shaft (10), both of which are installed in the sewing machine. A lifting lever (9) and a connecting seat (111) are rotatably mounted on the rotating shaft (10). One end of the lifting lever (9) is connected to the output shaft (21) of the drive motor (2), and the other end is provided with a first contact surface (91) for abutting against the lower surface of the connecting seat (111). The connecting seat (111) is connected to the middle pressure foot (12). When the lifting lever (9) rotates around the rotating shaft (10) under the drive of the drive motor (2), the connecting seat (111) rotates synchronously around the rotating shaft (10), thereby causing the middle pressure foot (12) to rise or fall.

2. The height adjustment mechanism for the middle pressure foot according to claim 1, characterized in that, It also includes a limiting member (4) disposed above the lifting lever (9). When the lifting lever (9) abuts against the limiting member (4), the middle pressure foot (12) is located at the lower stop of its lifting stroke.

3. The height adjustment mechanism for the middle pressure foot according to claim 2, characterized in that, It also includes a mounting base (1) disposed in the sewing machine, and the drive motor (2) and the limiting member (4) are both disposed on the mounting base (1).

4. The height adjustment mechanism for the middle pressure foot according to claim 1, characterized in that, It also includes a position sensor (7) that is signal-connected to the drive motor (2), the position sensor (7) being used to detect whether the output shaft (21) has rotated to a preset angle.

5. The height adjustment mechanism for the middle pressure foot according to claim 4, characterized in that, It also includes a sensor (8) disposed on the output shaft (21), and the position sensor (7) is used to detect whether the sensor (8) has moved into position.

6. The height adjustment mechanism for the middle pressure foot according to claim 1, characterized in that, The output shaft (21) is provided with a lifting crank (5), and one end of the lifting lever (9) is rotatably connected to the end of the lifting crank (5) through a lifting connecting rod (6).

7. A sewing machine, characterized in that, Includes the pressure foot height adjustment mechanism as described in any one of claims 1-6.

8. The sewing machine according to claim 7, characterized in that, It also includes an upper shaft (14) rotatably disposed in the sewing machine, the upper shaft (14) being connected to the middle presser foot (12) via a follower mechanism (11); the connecting seat (111) is rotatably connected to the follower mechanism (11).

9. The sewing machine according to claim 8, characterized in that, The follower mechanism (11) includes an eccentric wheel (113) mounted on the upper shaft (14), a pressure arm shaft (115), a first crank (116) mounted at one end of the pressure arm shaft (115), a second crank (117) mounted at the other end of the pressure arm shaft (115), an eccentric wheel connecting rod (114) for connecting the first crank (116) and the eccentric wheel (113), a connecting crank (112), and a swing connecting rod (118) for connecting the second crank (117) and the connecting crank (112). The connecting crank (112) is L-shaped, with its upper end connected to the swing connecting rod (118), its middle part rotatably engaged with the connecting seat (111), and its left end rotatably connected to the pressure foot drive rod (131). The pressure foot drive rod (131) is connected to the middle pressure foot (12) through the pressure foot rod (13).

10. The sewing machine according to claim 9, characterized in that, It also includes guide rods extending vertically. The presser foot rod (13) is slidably coupled to the guide rod. A spring (15) and a spring tube sleeve are respectively sleeved on the guide rod. The upper end of the spring (15) abuts against the upper end of the guide rod, and the lower end abuts against the spring tube sleeve. The spring tube sleeve abuts against the boss provided on the connecting seat (111).

Images