A presser foot head with automatic pressure adjustment

Abstract

This utility model discloses a presser foot head with automatic pressure adjustment, including a presser foot handle and a presser foot base plate disposed at the bottom of the presser foot handle; the bottom of the presser foot base plate has a recess, and multiple movable plates are engaged in the recess; a first spring rod is longitudinally arranged between the movable plates and the top of the recess; a first airbag is provided at the bottom of the movable plate, and a contact plate is provided at the bottom of the first airbag; a second spring rod is respectively provided on both sides of the recess at the connection of the movable plates, and a friction plate is provided on the second spring rod; a second airbag is provided between the friction plates that are in contact on both sides of the same movable plate through a connecting rod; by setting a linkage structure of movable plates, first airbags and second airbags that are slidably connected to the recess of the presser foot base plate, the friction force between the movable plates and the friction plates can be automatically adjusted according to the fabric thickness, thereby dynamically controlling the pressure applied by the presser foot to the fabric; achieving precise pressing.

Description

Technical Field

[0001] This utility model relates to the field of sewing machine technology, specifically to a presser foot head with automatic pressure adjustment. Background Technology

[0002] In textile manufacturing, garment processing, and leather product production, the presser foot, as a core component of sewing equipment, is primarily used to apply vertical pressure to materials during sewing. This ensures that fabrics, leather, and other materials remain flat during feeding, preventing slippage or wrinkling, thereby guaranteeing uniform stitching and product quality. Traditional presser foot pressure adjustment relies on mechanical spring rods, counterweights, or pneumatic devices. The pressure value is typically preset via a manual knob or lever and remains fixed during operation.

[0003] However, with the increasing demands of modern manufacturing for flexible, intelligent, and high-precision processing, the limitations of traditional static pressure adjustment methods are becoming increasingly apparent. Different materials and layer thicknesses require significantly different pressures. For example, thin fabrics require low pressure to avoid indentations, while multi-layered thick materials require high pressure to prevent displacement. Traditional presser feet cannot sense material characteristics in real time and dynamically adjust pressure, leading to frequent machine stops for manual adjustments by operators, resulting in low efficiency and reliance on experience.

[0004] In high-speed sewing or complex stitch processing, fluctuations in pressure requirements can occur due to variations in material surface friction, uneven thickness, and instantaneous changes in feed speed. Traditional presser feet struggle to accurately follow the subtle changes in fabric thickness, easily leading to skipped stitches, thread breakage, or material deformation. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model provides a presser foot head with automatic adjustment of pressing pressure.

[0006] The technical solution of this utility model is a presser foot head with automatic pressure adjustment: it includes a presser foot handle and a presser foot base plate set at the bottom of the presser foot handle; the bottom of the presser foot base plate has a groove, and multiple movable plates are engaged in the groove; the movable plates are longitudinally slidably connected to the inner sidewall of the groove, and a first spring rod is longitudinally arranged between the movable plates and the top of the groove.

[0007] The bottom of the movable plate is provided with a first airbag, the bottom of the first airbag is provided with a contact plate, and the two side walls of the sink groove located at the connection of the movable plate are respectively provided with a second spring rod, and a friction plate is provided on the second spring rod, and the friction plate slides in contact with the side wall of the movable plate.

[0008] A second airbag is provided between the friction pads located on both sides of the same movable plate via a connecting rod; the first airbag and the second airbag are connected by a conduit.

[0009] Note: The longitudinal sliding connection between the movable plate and the settling tank, along with the first spring rod, ensures both flexible lifting and lowering of the movable plate and provides a restoring elastic force to prevent mechanical jamming. The combination design of the friction plate and the second spring rod further enhances the response speed and accuracy of friction adjustment. In addition, the first airbag and the second airbag are connected by a conduit to form a linked pneumatic system, which simplifies the mechanical transmission structure and reduces manufacturing costs.

[0010] Furthermore, a ball bearing is rotatably provided at the bottom of the contact plate.

[0011] Explanation: By using rolling contact, the sliding friction resistance between the contact plate and the fabric is reduced, making the fabric push more smoothly under the presser foot and reducing the problem of fabric stretching, deformation or wrinkling caused by uneven friction.

[0012] Furthermore, the presser foot base plate is provided with a through groove for the sewing needle to pass through, and the bottom sides of the contact plate are provided with arc edges.

[0013] Note: The curved edge design creates a smooth transition surface, preventing sharp edges from scratching the fabric surface when the presser foot moves. It also guides the fabric to naturally conform to the contact plate, enhancing the grip on thin or smooth fabrics and preventing the fabric from shifting laterally during sewing.

[0014] Furthermore, the presser foot handle is composed of an inner handle and an outer handle that are slidably connected. The outer side wall of the inner handle is provided with a plurality of horizontally retractable protrusions at longitudinal intervals; the inner side wall of the outer handle is provided with a plurality of grooves that can be engaged with the protrusions one by one.

[0015] Description: The presser foot handle is height-adjustable through the interlocking structure of the inner and outer handles, adapting to different sewing machine models or other sewing scenarios. Utilizing the lateral telescopic characteristics of the protrusions and the limiting engagement of the grooves, multiple fixed positions are provided to ensure the stability of the presser foot handle after height adjustment. At the same time, it is easy to operate, requires no additional tools, and improves assembly efficiency.

[0016] Furthermore, two adjacent movable plates are slidably engaged, and a third spring rod is provided inside the second airbag.

[0017] Explanation: The sliding snap-fit ​​enhances the lateral linkage constraint between adjacent movable plates, preventing misalignment and tilting of the movable plates when subjected to force on one side, ensuring the synchronicity of the coordinated lifting and lowering of multiple movable plates, and maintaining uniform pressure on the fabric by the presser foot plate; it provides auxiliary elastic support during the inflation and deflation of the second airbag, accelerates airbag reset and inhibits excessive deformation of the airbag, extends the service life of the airbag, and at the same time, the auxiliary friction plate responds quickly to air pressure changes, improving the system's adjustment sensitivity.

[0018] The beneficial effects of this utility model are as follows: By setting a linkage structure of a movable plate, a first airbag, and a second airbag that are slidably connected to the groove of the presser foot base plate, the friction force between the movable plate and the friction plate can be automatically adjusted according to the fabric thickness, thereby dynamically controlling the pressure applied by the presser foot to the fabric; when sewing thick fabric, the movable plate in contact with the thick fabric is subjected to greater compression, causing the first airbag to deform, prompting the second airbag to inflate and expand, driving the friction plate to disengage from the side wall of the movable plate, significantly reducing frictional resistance, ensuring that the movable plate moves smoothly upward to reduce the pressure of the presser foot on the fabric, and avoiding fabric deformation or damage. When sewing thin fabrics, the movable plate experiences less compression, resulting in insufficient inflation of the second airbag. The friction plate, under the action of the second spring rod, adheres tightly to the side wall of the movable plate, limiting its movement through high friction. This maintains greater pressure from the presser foot on the fabric, preventing slippage or deviation. This design allows the presser foot pressure to adaptively adjust with fabric thickness, effectively improving the sewing machine's adaptability to different fabric thicknesses and the stability of sewing quality. It achieves precise pressing, avoiding problems such as skipped stitches, thread breakage, or material deformation. Furthermore, its compact structure requires no manual intervention, significantly improving production efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this utility model;

[0020] Figure 2 This is a bottom view of the overall structure of Embodiment 1 of this utility model;

[0021] Figure 3 This is a longitudinal sectional view of the presser foot base plate of Embodiment 1 of this utility model;

[0022] Figure 4 This is a longitudinal sectional view of the end face of the presser foot base plate of Embodiment 1 of this utility model;

[0023] Figure 5 This is a cross-sectional view of the presser foot base plate of Embodiment 1 of this utility model;

[0024] Among them, 1-presser foot handle, 11-protrusion, 12-groove, 2-presser foot base plate, 21-through groove, 3-movable plate, 31-first spring rod, 4-first airbag, 5-second spring rod, 51-telescopic rod, 6-friction plate, 7-connecting rod, 8-second airbag. Detailed Implementation

[0025] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0026] Example 1: As Figure 1 , 2The presser foot head shown includes a presser foot handle 1 and a presser foot base plate 2 disposed at the bottom of the presser foot handle 1; the bottom of the presser foot base plate 2 has a recess, and five movable plates 3 are engaged in the recess; the movable plates 3 are longitudinally slidably connected to the inner sidewall of the recess; a first spring rod 31 is longitudinally disposed between the movable plates 3 and the top of the recess; there is a 0.5mm gap between two adjacent movable plates 3;

[0027] like Figure 1 , 2 As shown, the presser foot handle 1 is composed of an inner handle and an outer handle that are slidably connected. The outer side wall of the inner handle is provided with a plurality of horizontally retractable protrusions 11 at longitudinal intervals. The inner side wall of the outer handle is provided with a plurality of grooves 12 that can be engaged with the protrusions 11 one by one. The presser foot base plate 2 is provided with a through groove 21 for the sewing needle to pass through, and the bottom sides of the contact plate are provided with arc edges.

[0028] like Figures 3-5 The movable plate 3 shown is provided with a first airbag 4 at its bottom, and a contact plate at its bottom. A second spring rod 5 and a telescopic rod 51 for limiting movement are respectively provided on the two side walls of the sink at the connection of the movable plate 3. A friction plate 6 is provided on the second spring rod 5, and the friction plate 6 slides in contact with the side wall of the movable plate 3. The movement trajectory of the friction plate 6 is limited by the telescopic rod 51 to prevent the friction plate 6 from deflecting when moving.

[0029] A second airbag 8 is provided between the friction pads 6 located on both sides of the same movable plate 3 via a connecting rod 7; the first airbag 4 and the second airbag 8 are connected by a conduit.

[0030] The working principle of this embodiment is as follows:

[0031] When the fabric is moved during sewing, if a thicker piece of fabric is encountered, the thicker fabric presses against the contact plate, pushing the movable plate 3 upward. The first airbag 4 is pressurized and injects gas into the second airbag 8 through a conduit, causing it to expand. This expansion, along with the connecting rod 7, drives the friction plates 6 on both sides to overcome the elasticity of the second spring rod 5 and move away from the side wall of the movable plate 3. The friction is greatly reduced, and the movable plate 3 slides flexibly under the action of the first spring rod 31. The pressure of the presser foot on the fabric is reduced, preventing the problem of stretching and jamming of thick fabric due to constant high pressure from the presser foot. Conversely, when the pressing effect of thin fabric is weak, the deformation of the first airbag 4 is small, and the second airbag 8 is underinflated. The friction plates 6 are pressed tightly against the side wall of the movable plate 3 under the action of the second spring rod 5, limiting the movement of the movable plate 3 through high friction. This allows the presser foot to maintain a large pressure on the fabric through the first spring rod 31, achieving adaptive pressure adjustment. The first airbag 4 is made of rubber and has a thickness of 1mm under normal inflation.

[0032] Example 2: The difference between this example and Example 1 is that a ball bearing is provided at the bottom of the contact plate. Specifically, the ball bearing is rotatably embedded at the bottom of the contact plate.

[0033] Example 3: The difference between this example and Example 1 is that the two adjacent movable plates 3 are slidably engaged, and a third spring rod is provided inside the second airbag 8; the friction force between the adjacent movable plates 3 is adjustable in the range of 0.1-0.2N after testing.

Claims

1. A presser foot head with automatically adjustable pressing pressure, characterized in that, Includes a presser foot handle (1) and a presser foot base plate (2) set at the bottom of the presser foot handle (1); the bottom of the presser foot base plate (2) has a groove, and multiple movable plates (3) are engaged in the groove. The movable plates (3) are longitudinally slidably connected to the inner sidewall of the groove, and a first spring rod (31) is longitudinally arranged between the movable plates (3) and the top of the groove. The bottom of the movable plate (3) is provided with a first airbag (4), the bottom of the first airbag (4) is provided with a contact plate, and the two side walls of the sink at the connection of the movable plate (3) are respectively provided with a second spring rod (5), and a friction plate (6) is provided on the second spring rod (5). The friction plate (6) slides in contact with the side wall of the movable plate (3). A second airbag (8) is provided between the friction pads (6) located on both sides of the same movable plate (3) via a connecting rod (7); the first airbag (4) and the second airbag (8) are connected by a conduit.

2. The presser foot head with automatic pressure adjustment according to claim 1, characterized in that, The bottom of the contact plate is equipped with ball bearings.

3. The presser foot head with automatic pressure adjustment according to claim 1, characterized in that, The bottom sides of the contact plate are provided with arc edges.

4. The presser foot head with automatic pressure adjustment according to claim 1, characterized in that, The two adjacent movable plates (3) are slidably engaged, and a third spring rod is provided inside the second airbag (8).

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