A non-backlash tensioner

Abstract

The application discloses a kind of anti-derailment pullers, including shell, pull rope, driving wheel, transmission part, adjusting mechanism, multiple driven wheels and spring, driving wheel is rotatably connected in shell, pull rope is wound on it, multiple driven wheels are coaxially arranged with driving wheel, rotatably connected in shell, spring is installed between driven wheel and shell, transmission part realizes transmission between driving wheel and at least one driven wheel, adjusting mechanism drives transmission part axial movement, to adjust the number of driven wheel access and force level, adjusting mechanism includes lead screw, axial stop nut and anti-rotation component, lead screw one end is coaxially rotatably connected with transmission part, and moves synchronously with transmission part axial motion, axial stop nut is threadedly connected with lead screw, and is rotatably installed in shell, driven by electricity or manually.This application aims to provide a kind of anti-derailment puller, with the advantages of preventing accidental change of force level during exercise, improving the stability and safety of exercise.

Description

Technical Field

[0001] This invention relates to the field of fitness equipment, and more specifically, to an anti-gear shifting resistance band. Background Technology

[0002] Resistance bands, as common home workout equipment, are widely used for muscle training and strength improvement. Existing resistance band structures include... Figure 11 The device includes a housing 201, a drive wheel 202, multiple driven wheels 203, a spring 204, a lead screw nut 205, a lead screw 206, and a pull rope 207. The drive wheel is rotatably connected inside the housing, and the pull rope is wound around it. Multiple driven wheels are coaxially arranged with the drive wheel and are also rotatably connected in the housing. The drive wheel and the driven wheels are respectively provided with an active transmission groove 208 and a passive transmission groove 209 at their centers. One end of the lead screw nut is slidably connected in the active transmission groove and is connected to the drive wheel for transmission. The other end slides through the passive transmission groove and enters at least one driven wheel to realize the transmission between the drive wheel and the driven wheel. The spring is installed between the driven wheel and the housing to provide rotational resistance to the driven wheel. The lead screw is rotatably connected in the housing and is threadedly engaged with the lead screw nut, and the lead screw is fixed in the axial direction.

[0003] During use, the user pulls the rope, causing the drive wheel to rotate. The drive wheel, via a screw nut, drives the driven wheels to rotate, thus achieving the exercise function. This resistance band has a force adjustment mechanism: rotating the screw causes relative rotation between the screw and the screw nut, moving the screw nut axially. When the screw nut inserts more driven wheels, the drive wheel rotates, simultaneously driving more driven wheels, increasing the resistance of the resistance band. When the screw nut retracts from some driven wheels, the number of driven wheels driven simultaneously decreases, and the resistance decreases accordingly.

[0004] However, after prolonged use, the rotational resistance between the lead screw and the housing in existing resistance bands gradually increases. During exercise, the lead screw nut rotates with the drive wheel, but due to excessive rotational resistance, the lead screw may experience a decrease in speed or come to a complete stop. At this point, relative rotation occurs between the lead screw nut and the lead screw, causing axial displacement of the lead screw nut. This displacement changes the number of wheels the lead screw nut passes through, thus unexpectedly altering the resistance band's intensity level during exercise. Sudden changes in intensity levels not only affect the stability of the exercise effect but may also cause the user to lose control due to sudden changes in resistance, posing a safety hazard. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-gear shift resistance band, which has the advantages of preventing accidental changes in resistance level during exercise, thereby improving the stability and safety of exercise.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An anti-gear shifting tensioner includes a housing, a pull rope, a drive wheel, a transmission component, an adjustment mechanism, multiple driven wheels, and a spring. The drive wheel is rotatably connected to the housing, with the pull rope wound around it. The multiple driven wheels are coaxially arranged with the drive wheel and rotatably connected to the housing. The spring is installed between the driven wheels and the housing. The transmission component enables transmission between the drive wheel and at least one driven wheel. The adjustment mechanism drives the transmission component to move axially to adjust the number of driven wheels engaged and the gear level. The adjustment mechanism includes a lead screw, an axial stop nut, and an anti-rotation component. One end of the lead screw is rotatably connected to the transmission component on the same axis and moves axially synchronously with the transmission component. The axial stop nut is threadedly connected to the lead screw and rotatably installed in the housing. It is driven electrically or manually. The anti-rotation component prevents the lead screw from rotating on its own.

[0007] Furthermore, the side of the lead screw is provided with a stop plane parallel to its own axis, and the anti-rotation component is a stop block. The stop block is fixedly installed in the housing and is provided with a D-shaped hole that matches the lead screw. The lead screw passes through the stop block through the D-shaped hole.

[0008] Furthermore, the driving wheel and the driven wheel are respectively provided with an active transmission groove and a driven transmission groove adapted to the transmission component at their centers. One end of the transmission component is slidably connected to the active transmission groove on the same axis, and the other end extends into the driven transmission groove of at least one driven wheel.

[0009] Furthermore, both the driving and driven transmission slots are splined, and the outer periphery of the transmission component is provided with splines that are adapted to the splined slots. The ends of the splined slots are provided with a first chamfer, and the ends of the splines are provided with a second chamfer, so that the splines can extend into the splined slots.

[0010] Furthermore, the housing has a mounting cavity on the side of the driven wheel away from the driving wheel, the rotating end of the lead screw is located at the end of the transmission component away from the driving wheel, the free end of the lead screw extends into the mounting cavity, the outer side of the axial stop nut is provided with a first tooth, and a first drive gear is rotatably connected in the mounting cavity, the first drive gear meshes with the first tooth; When the axial stop nut is electrically driven, a DC motor, a displacement sensor, a controller, and a battery are installed in the mounting cavity. The DC motor is connected to the first drive gear and is controlled by the controller. The battery is used for power supply, and the sensor is used to detect the axial movement distance of the lead screw. When the axial locking nut is manually driven, a handwheel is rotatably mounted on the end of the housing, and the handwheel is connected to the first drive gear through the transmission shaft.

[0011] Furthermore, when the axial locking nut is electrically driven, the controller integrates a wireless module, which can connect wirelessly to a mobile phone or remote control.

[0012] Furthermore, when the axial stop nut is manually driven, the inner peripheral wall of the mounting cavity is cylindrical, and a shift ring is rotatably connected inside the mounting cavity. The outer peripheral wall of the shift ring fits against the inner peripheral wall of the mounting cavity. The inner peripheral wall of the shift ring is provided with a second tooth. A transmission gear is coaxially fixedly connected to the transmission shaft. The transmission gear meshes with the second tooth. Multiple shift marks are provided on the outer peripheral wall of the shift ring. A viewing window is provided on one side of the housing, and one of the shift marks is located at the viewing window.

[0013] Furthermore, the transmission component is a tubular structure, with the lead screw coaxially arranged within it. An annular gap is formed between the transmission component and the lead screw. The end of the lead screw away from the drive wheel is rotatably connected to the end of the transmission component away from the drive wheel. An anti-rotation groove is coaxially provided inside the lead screw. The anti-rotation component is a square steel that fits the anti-rotation groove. The end of the square steel is slidably connected in the anti-rotation groove and fixedly connected to the housing. The axial stop nut is a threaded sleeve structure with internal threads, installed in the active transmission groove to save axial space in the housing. The outer diameter of the axial stop nut is smaller than the inner diameter of the transmission component. The axial stop nut extends into the transmission component and is threadedly connected to the lead screw. The end of the axial stop nut extends outside the housing for driving.

[0014] Furthermore, a gear-shaped handwheel is fixedly connected to the outer end of the axial stop nut for easy manual drive. An electric unit is detachably connected to one end of the housing near the gear-shaped handwheel. The electric unit includes an end cover, a servo motor, and a second drive gear. The servo motor is connected to the gear-shaped handwheel via the second drive gear. The end cover is detachably connected to the end of the housing, covering the gear-shaped handwheel, the second drive gear, and the servo motor.

[0015] Furthermore, a rope outlet is provided on the side of the housing corresponding to the drive wheel. The pull rope extends to the outside of the housing through the rope outlet. When the electric unit is installed at the end of the housing, the center of gravity of the tensioner is close to the rope outlet. A strap is provided on the side of the housing facing away from the rope outlet to facilitate fixing the tensioner.

[0016] Through the above improvements, the tensioner of the present invention has the following beneficial effects: 1. The anti-gear shifting resistance band of this application introduces a lead screw, an axial stop nut, and an anti-rotation component into the adjustment mechanism, making the lead screw and transmission component coaxially rotatably connected and synchronously moving axially. Simultaneously, the axial stop nut is rotatably installed in the housing and drives the lead screw to move axially, while the anti-rotation component effectively prevents the lead screw from rotating. Therefore, during the use of the resistance band, even if the rotational resistance between the lead screw and the transmission component increases, the lead screw will not rotate due to the rotation of the transmission component, thus avoiding axial displacement of the transmission component during exercise, ensuring the stability of the resistance band's gear settings, and effectively solving the problem of force changes during use in existing resistance bands. 2. Both the driving and driven transmission slots utilize splined grooves, and the outer circumference of the transmission component is provided with splines adapted to the splined grooves. This ensures that the transmission connection between the transmission component and the driving and driven wheels not only reliably transmits torque but also exhibits excellent sliding performance during axial movement. Furthermore, the chamfering effectively guides the splines to align smoothly and quickly into the splined grooves, significantly reducing jamming, impact, and wear caused by misalignment. 3. The axial locking nut is designed as a threaded sleeve structure and installed in the active transmission groove. Its outer diameter is smaller than the inner diameter of the transmission component and extends into the transmission component. This highly integrated nested design greatly shortens the axial length of the entire tensioner, significantly saves valuable space inside the housing, and improves the portability of the tensioner. 4. The gear-shaped handwheel, fixedly connected to the outer end of the axial locking nut, not only provides users with a convenient manual drive method, but its gear structure also provides a standardized interface for subsequent electric drive. The detachable electric unit, including the end cover, servo motor, and second drive gear, can be connected to the gear-shaped handwheel via the second drive gear, thereby realizing flexible switching between manual and electric drive methods and modular upgrades; 5. When the electric unit is installed at the end of the housing, it can be used to balance multiple passive wheels, bringing the center of gravity of the tensioner closer to the rope outlet. This makes the tensioner more stable under stress, reduces the risk of tipping over, and thus improves the safety of use. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an electrically driven tensioner as an example.

[0018] Figure 2 for Figure 1 Enlarged view of point A.

[0019] Figure 3 for Figure 1 The internal view.

[0020] Figure 4 for Figure 3 Enlarged view of point B.

[0021] Figure 5 This is a schematic diagram of the driven wheel in an embodiment.

[0022] Figure 6 This is a schematic diagram of the transmission component in an embodiment.

[0023] Figure 7 This is a schematic diagram of a manually driven tensioner as an example.

[0024] Figure 8 This is a schematic diagram of another anti-rotation component in an embodiment.

[0025] Figure 9 This is a schematic diagram of a tensioner with another type of adjustment mechanism.

[0026] Figure 10 for Figure 9 The diagram shown illustrates the adjustment of the tensioner.

[0027] Figure 11 This is a schematic diagram of a traditional tension device. Detailed Implementation

[0028] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0029] In traditional resistance bands, after prolonged use, the rotational resistance between the lead screw and the housing may increase. This can cause the lead screw to rotate at a reduced speed or even stop rotating during use. Consequently, relative rotation occurs between the lead screw and the nut, leading to axial misalignment of the lead screw and nut. In severe cases, this can alter the resistance level during use, affecting user experience and workout results.

[0030] In this regard, such as Figures 1 to 7 This application discloses an anti-gear shifting tension device, which includes a housing 3, a pull rope 4, a drive wheel 5, a transmission component 6, an adjustment mechanism, multiple driven wheels 7, and a spring 8. The drive wheel 5 is rotatably connected to the housing 3, and the pull rope 4 is wound around it. The multiple driven wheels 7 are coaxially arranged with the drive wheel 5 and rotatably connected to the housing 3. The spring 8 is installed between the driven wheels 7 and the housing 3. The transmission component 6 realizes transmission between the drive wheel 5 and at least one driven wheel 7. The adjustment mechanism drives the transmission component 6 to move axially to adjust the number of driven wheels 7 engaged and the gear level. The adjustment mechanism further includes a lead screw 9, an axial stop nut 10, and an anti-rotation component 11. One end of the lead screw 9 is rotatably connected to the transmission component 6 on the same axis and moves axially synchronously with the transmission component 6. The axial stop nut 10 is threadedly connected to the lead screw 9 and rotatably installed in the housing 3, driven electrically or manually. The anti-rotation component 11 prevents the lead screw 9 from rotating.

[0031] Specifically, this embodiment provides an anti-gear shifting puller, whose structure includes a housing 3, a pull rope 4, a drive wheel 5, a transmission component 6, multiple driven wheels 7, and a spring 8. The housing 3 serves as the main load-bearing structure of the puller, housing and supporting other functional components. The user drives the puller by pulling the pull rope 4. The drive wheel 5 is the active component of the puller, responsible for receiving the tension from the pull rope 4 and converting it into rotational motion. Multiple driven wheels 7 work in conjunction with the drive wheel 5 to provide resistance. The transmission component 6 is responsible for transmitting power between the drive wheel 5 and the driven wheels 7. An adjustment mechanism is used to adjust the resistance of the puller. The spring 8 provides the necessary resistance to the driven wheels 7.

[0032] Specifically, the drive wheel 5 is rotatably connected inside the housing 3, and the pull rope 4 is wound around the outer circumference of the drive wheel 5. When the user pulls the pull rope 4, the drive wheel 5 rotates accordingly. As one implementation, the drive wheel 5 can be connected to the housing 3 using a bearing structure to ensure smooth rotation.

[0033] Multiple driven wheels 7 are coaxially arranged with the drive wheel 5 and are rotatably connected in the housing 3. These driven wheels 7 can be arranged along the axis of the drive wheel 5, and each driven wheel 7 can rotate independently.

[0034] A spring 8 is installed between each driven wheel 7 and the housing 3. The function of the spring 8 is to provide rotational resistance to the driven wheel 7. When the driven wheel 7 rotates, the spring 8 deforms, thereby providing a reaction force. For example, a torsion spring can be used, with its inner end fixed to the driven wheel 7 and its outer end fixed to the housing 3. When the driven wheel 7 rotates, the spring 8 deforms, generating resistance.

[0035] The function of the transmission component 6 is to realize the transmission between the drive wheel 5 and at least one driven wheel 7. The transmission component 6 can be an axially movable part that transmits the rotation of the drive wheel 5 to the selected driven wheel 7. For example, the transmission component 6 can be a sleeve, one end of which mates with the center hole of the drive wheel 5, and the other end of which mates with the center holes of one or more driven wheels 7. The number of driven wheels 7 mates with the transmission component 6 can be adjusted by axial movement. When the drive wheel 5 is driven by the pull rope 4, the drive wheel 5, the transmission component 6, and the corresponding number of driven wheels 7 rotate synchronously.

[0036] The adjusting mechanism drives the transmission component 6 to move axially, thereby adjusting the number of driven wheels 7 engaged and the force level. By changing the number of driven wheels 7 that rotate in conjunction with the drive wheel 5, the total resistance provided by the tensioner can be changed.

[0037] The adjusting mechanism further includes a lead screw 9, an axial stop nut 10, and an anti-rotation component 11. The lead screw 9 is the core transmission element in the adjusting mechanism, achieving axial displacement through its threaded structure. The axial stop nut 10 is threadedly engaged with the lead screw 9, driving the lead screw 9 to move axially through its own rotation. The anti-rotation component 11 ensures that the lead screw 9 does not rotate during axial movement.

[0038] One end of the lead screw 9 is rotatably connected to the transmission component 6 on the same axis, and moves axially synchronously with the transmission component 6. This means that when the lead screw 9 moves axially, the transmission component 6 also moves accordingly.

[0039] The axial stop nut 10 is threadedly connected to the lead screw 9 and is rotatably mounted in the housing 3. The axial stop nut 10 can be driven electrically or manually. When the axial stop nut 10 rotates, the lead screw 9 will be forced to move axially due to its threaded engagement with the lead screw 9.

[0040] The anti-rotation component 11 prevents the lead screw 9 from rotating on its own. The anti-rotation component 11 ensures that the lead screw 9 only moves axially. If the lead screw 9 rotates during the axial movement driven by the rotation of the axial stop nut 10, it will affect the accuracy of the adjustment. Furthermore, during the resistance training phase, the anti-rotation block prevents the lead screw from rotating unexpectedly and causing the transmission component 6 to move axially unexpectedly, thereby preventing accidental gear shifting during resistance training and improving training stability and safety.

[0041] The anti-gear shifting resistance band of this application introduces a lead screw 9, an axial stop nut 10, and an anti-rotation component 11 into the adjustment mechanism. The lead screw 9 and the transmission component 6 are coaxially rotatably connected and move synchronously axially. Simultaneously, the axial stop nut 10 is rotatably mounted in the housing 3 and drives the lead screw 9 to move axially. The anti-rotation component 11 effectively prevents the lead screw 9 from rotating. Therefore, during the use of the resistance band, even if the rotational resistance between the lead screw 9 and the transmission component 6 increases, the lead screw 9 will not rotate due to the rotation of the transmission component 6. This avoids axial displacement of the transmission component 6 during exercise, ensuring the stability of the resistance band's gear settings and effectively solving the problem of force changes during use in existing resistance bands.

[0042] In one embodiment, this application further proposes that the side of the lead screw 9 is provided with a stop plane 12 parallel to its own axis, and the anti-rotation component 11 is a stop block. The stop block is fixedly installed in the housing 3 and is provided with a D-shaped hole 13 adapted to the lead screw 9. The lead screw 9 passes through the stop block through the D-shaped hole 13. Specifically, the side of the lead screw 9 is provided with a stop plane 12 parallel to its own axis, which means that the cross-section of the lead screw 9 is no longer a perfect circle, but has one or more flat sides, such as forming a D-shaped cross-section. The stop plane 12 is formed by machining, grinding, or molding, and its main function is to provide a non-circular contact surface for the anti-rotation component 11 to prevent the lead screw 9 from rotating around its axis. The anti-rotation component 11 is specifically defined as a stop block, which is a solid component, usually made of rigid materials such as metal or engineering plastics. Its function is to cooperate with the stop plane 12 of the lead screw 9 to achieve anti-rotation. The stop block is fixedly installed in the housing 3 to ensure that it remains stationary when the tensioner is working. The stop block is provided with a D-shaped hole 13 that is adapted to the lead screw 9. The shape of the D-shaped hole 13 precisely matches the D-shaped cross-section of the lead screw 9, allowing the lead screw 9 to slide freely in the axial direction and preventing any rotation of the lead screw 9. The lead screw 9 passes through the stop block through the D-shaped hole 13, forming a sliding fit relationship between the lead screw 9 and the stop block, ensuring that the rotational motion of the lead screw 9 is effectively limited when it moves axially.

[0043] With the above configuration, the lead screw 9 is designed with a non-circular cross-section having a stop plane 12, and is used in conjunction with a stop block with a D-shaped hole 13 fixed in the housing 3, forming a mechanism that is simple in structure, easy to manufacture, and has a reliable anti-rotation effect. This design can effectively prevent the lead screw 9 from rotating during axial movement, thereby ensuring the accuracy and stability of the adjustment mechanism when adjusting the number and force levels of the driven wheel 7.

[0044] In one embodiment, such as Figure 8 An optimized anti-rotation component is proposed, comprising a guide rod 41 and a slider 42. The end of the lead screw is milled to form a D-shaped cross-section. One end of the slider has a connecting hole 43 that matches the end of the lead screw, and the end of the lead screw passes through the connecting hole 43 of the slider and is locked in place by a locking component 44, thus achieving locking between the end of the lead screw and the slider. The guide rod is parallel to the lead screw and is fixed in the housing by welding, screws, or threads. The other end of the slider has a sliding groove 45 that matches the guide rod, allowing for sliding contact with the guide rod. When the lead screw moves axially, it drives the slider to move synchronously along the guide rod. The guide rod serves to guide and prevent rotation, improving the stability of the slider while preventing the slider and lead screw from rotating around the lead screw axis.

[0045] With the above settings, the anti-rotation function of the lead screw is achieved through the coordinated action of the slider and the guide rod, while the axial movement of the lead screw is smoother and more stable.

[0046] In one embodiment, the present application further proposes that the driving wheel 5 and the driven wheel 7 are respectively provided with an active transmission groove 14 and a driven transmission groove 15 adapted to the transmission member 6 at their centers. One end of the transmission member 6 is coaxially slidably connected in the active transmission groove 14, and the other end extends into the driven transmission groove 15 of at least one driven wheel 7.

[0047] Specifically, both the drive wheel 5 and the driven wheel 7 have transmission grooves at their centers. The structure and dimensions of these transmission grooves match the external features of the transmission component 6, aiming to provide a through-passage or insertion channel for the transmission component 6 and ensure that the transmission component 6 maintains a coaxial relationship with the drive wheel 5 and the driven wheel 7 during axial movement. These transmission grooves can be spline grooves, D-shaped hole grooves, square hole grooves, or other grooves with specific cross-sectional shapes. Their design allows the transmission component 6 to slide axially within them while restricting its radial or circumferential relative movement to achieve transmission and gear adjustment purposes.

[0048] One end of the transmission component 6 is coaxially and slidably connected to the drive transmission groove 14 at the center of the drive wheel 5. This means that the axis of the transmission component 6 coincides with the rotation axis of the drive wheel 5, and the transmission component 6 can slide freely along its axial direction inside the drive transmission groove 14. This sliding connection allows the drive wheel 5 to still transmit torque to the driven wheel 7 through the transmission component 6 after the transmission component 6 has been axially moved and shifted.

[0049] The other end of the transmission member 6 extends and inserts into the driven transmission groove 15 of at least one driven wheel 7. Similar to the driving transmission groove 14, the driven transmission groove 15 also adapts to the transmission member 6, allowing the transmission member 6 to slide axially within it. This design allows the transmission member 6 to selectively connect or disconnect with one or more driven wheels 7 depending on its axial position. As the transmission member 6 moves axially, it sequentially passes through or disengages from the driven transmission grooves 15 of different driven wheels 7, thereby changing the number of driven wheels 7 connected to the transmission member 6 and thus adjusting the force setting of the tensioner.

[0050] By setting an active transmission groove 14 and a driven transmission groove 15 adapted to the transmission component 6 at the center of the drive wheel 5 and the driven wheel 7 respectively, and making one end of the transmission component 6 coaxially slidably connected in the active transmission groove 14, and the other end extending into the driven transmission groove 15 of at least one driven wheel 7, this application effectively solves the connection problem between the transmission component 6 and the drive wheel 5 and the driven wheel 7 during axial movement. This design allows the transmission component 6 to achieve precise axial sliding while maintaining a coaxial relationship with the drive wheel 5 and the driven wheel 7, thereby driving the transmission component 6 to accurately adjust the number of driven wheels 7 engaged, achieving the purpose of gear adjustment.

[0051] In one embodiment, this application further proposes that both the active transmission groove 14 and the driven transmission groove 15 adopt spline grooves, and the outer periphery of the transmission member 6 is provided with splines adapted to the spline grooves. The end of the spline groove is provided with a first chamfer 16, and the end of the spline is provided with a second chamfer 17, so that the spline extends into the spline groove.

[0052] With the above configuration, both the active transmission groove 14 and the driven transmission groove 15 adopt spline grooves, and the outer periphery of the transmission component 6 is provided with splines adapted to the spline grooves. This ensures that the transmission connection between the transmission component 6 and the drive wheel 5 and driven wheel 7 can not only reliably transmit torque, but also has good sliding performance during axial movement. The multi-tooth meshing characteristic of the spline connection effectively disperses the load and improves transmission stability. Furthermore, the first chamfer 16 and the second chamfer 17 at the end of the spline groove together form an efficient guiding mechanism. When the adjusting mechanism drives the transmission component 6 to move axially to adjust the number of driven wheels 7 engaged, these two chamfers can effectively guide the splines to smoothly and quickly align and insert into the spline groove, significantly reducing jamming, impact, and wear caused by misalignment. This ensures a smoother and more reliable meshing process between the transmission component 6 and the transmission groove, thereby making the adjustment of the force level more precise and stable, greatly improving the operating experience and equipment life of the anti-gear shifting tensioner in actual use.

[0053] In one embodiment, this application further proposes that the housing 3 has a mounting cavity 18 on the side of the driven wheel 7 away from the driving wheel 5, the rotating end of the lead screw 9 is located at the end of the transmission member 6 away from the driving wheel 5, the free end of the lead screw 9 extends into the mounting cavity 18, the outer side of the axial stop nut 10 is provided with a first tooth, and a first drive gear 20 is rotatably connected in the mounting cavity 18, the first drive gear 20 meshes with the first tooth; when the axial stop nut 10 is electrically driven, a DC motor 21, a displacement sensor, a controller and a battery are installed in the mounting cavity 18, the DC motor 21 is connected to the first drive gear 20 and controlled by the controller, the battery is used for power supply, and the displacement sensor is used to detect the axial movement distance of the lead screw; When the axial stop nut 10 is manually driven, a handwheel 22 is rotatably mounted on the end of the housing 3, and the handwheel 22 is connected to the first drive gear 20 through the transmission shaft 23.

[0054] Specifically, the housing 3 has a mounting cavity 18 on the side of the driven wheel 7 away from the drive wheel 5. This mounting cavity 18 provides an independent, protected space for the mechanism driving the axial stop nut 10, and also provides clearance for the movement of the lead screw. The rotating end of the lead screw 9 is located at the end of the transmission member 6 away from the drive wheel 5, and the free end of the lead screw 9 extends into the mounting cavity 18. This layout ensures that the driving end of the lead screw 9 can be easily connected to the drive mechanism in the mounting cavity 18, while the main body of the lead screw 9 can still effectively cooperate with the transmission member 6. It provides a clear connection point for the drive mechanism and optimizes space utilization. The outer side of the axial stop nut 10 is provided with a first tooth. The first tooth is a mechanical transmission interface, usually manifested as a gear or gear ring structure. Its function is to receive the rotational force from the external drive source and transmit the force to the axial stop nut 10, causing it to rotate. This tooth design ensures the stability and efficiency of the drive force transmission. A first drive gear 20 is rotatably connected in the mounting cavity 18, and the first drive gear 20 meshes with the first tooth. The rotation of the first drive gear 20 can precisely control the rotation of the axial stop nut 10, thereby realizing the axial movement of the lead screw 9.

[0055] like Figure 1When the axial stop nut 10 is electrically driven, a DC motor 21, a displacement sensor, a controller, and a battery are installed in the mounting cavity 18. The DC motor 21 is connected to the first drive gear 20 and is controlled by the controller. The battery provides power. The DC motor 21 has a built-in reducer to amplify the output torque and improve shifting stability. The displacement sensor can be an encoder, which can be installed at the output end of the reducer or on the axial stop nut. By detecting the number of rotations, it can infer the axial movement distance of the lead screw. Alternatively, a non-contact displacement sensor, such as a photoelectric sensor or an infrared sensor, can be used, fixedly installed in the housing facing the end of the lead screw to detect the axial movement distance of the lead screw. In this electric drive mode, the DC motor 21 serves as the power source, driving the axial stop nut 10 through the first drive gear 20. The controller receives commands and controls the operating status of the DC motor, controlling the movement distance of the lead screw through the displacement sensor for precise gear switching. The battery provides an independent power supply for the entire electric drive system, allowing the tensioner to operate normally without an external power source, enhancing the portability of the equipment.

[0056] like Figure 7 When the axial stop nut 10 is manually driven, a handwheel 22 is rotatably mounted on the end of the housing 3. The handwheel 22 is connected to the first drive gear 20 via a transmission shaft 23. In this manual drive mode, the handwheel 22 serves as the user interface, allowing the user to directly adjust the force level by rotating it. The transmission shaft 23 transmits the rotational motion of the handwheel 22 to the first drive gear 20, thereby driving the axial stop nut 10. This manual drive method provides an intuitive and reliable backup or alternative adjustment means, and can be operated without electricity.

[0057] The above configuration provides a specific and efficient driving method for the axial stop nut 10 of the anti-gear shifting tensioner. The mounting cavity 18 and the reasonable arrangement of the free end of the lead screw 9 allow the drive mechanism to be integrated inside the housing 3, ensuring structural compactness and protection of internal components. The first tooth on the outer side of the axial stop nut 10 meshes with the first drive gear 20 inside the mounting cavity 18, forming a reliable mechanical transmission chain. In electric drive mode, the cooperation of the DC motor 21, controller, and battery enables electric control of the force level adjustment. Users can set or switch gears according to their needs, greatly improving ease of use and the level of intelligent training. Battery power also ensures the portability of the device. In manual drive mode, the handwheel 22 is connected to the first drive gear 20 via the transmission shaft 23, providing users with an intuitive, reliable, and power-free adjustment method, enhancing the adaptability of the device and the user experience.

[0058] In one embodiment, this application further proposes that when the axial stop nut 10 is electrically driven, the controller integrates a wireless module that can wirelessly connect to a mobile phone or remote control.

[0059] Specifically, the wireless module integrated into the controller is an electronic component capable of wireless communication. It typically contains core components such as a radio frequency transceiver, baseband processor, and antenna interface. This wireless module can convert digital signals generated by the controller into radio waves for transmission, and it can also receive external radio waves and convert them back into digital signals for the controller to process. In terms of implementation, this wireless module can be directly integrated onto the controller's main circuit board, forming a compact unit, or it can connect to the controller via a standard communication interface. Commonly used wireless communication technologies include, but are not limited to, Bluetooth and Wi-Fi, and the appropriate technology can be selected based on the specific application requirements for communication distance, power consumption, and data transmission rate.

[0060] This wireless connectivity allows users to remotely control the resistance band via external smart devices (such as smartphones) or a dedicated remote control.

[0061] With the above settings, the wireless module integrated into the controller enables the resistance band to connect wirelessly to a mobile phone or remote control, thus achieving remote, contactless adjustment of the resistance band's settings. During training, users can adjust the resistance in real time using their smartphones or remote controls, greatly improving the convenience and flexibility of operation.

[0062] In one embodiment, such as Figure 7 This application further proposes that when the axial locking nut 10 is manually driven, the inner peripheral wall of the mounting cavity 18 in the housing 3 is set as a cylindrical surface. A gear shift ring 24 is rotatably connected inside the mounting cavity 18, and the outer peripheral wall of the gear shift ring 24 fits against the inner peripheral wall of the mounting cavity 18. The inner peripheral of the gear shift ring 24 is provided with a second tooth, and a transmission gear 25 is coaxially fixedly connected to the transmission shaft 23, and the transmission gear 25 meshes with the second tooth. The outer peripheral of the gear shift ring 24 is provided with multiple gear position marks, and a viewing window 26 is provided on one side of the housing 3, with one gear position mark located at the viewing window 26.

[0063] Specifically, the inner circumferential wall of the mounting cavity 18 is cylindrical, which provides a precise rotational guide surface for the gear position ring 24, ensuring its stability and concentricity during rotation, thereby guaranteeing the accuracy of gear indication. The gear position ring 24 is an annular structure that can rotate freely within the mounting cavity 18 and serves as a visual indicator of the gear position. The outer circumferential wall of the gear position ring 24 fits tightly against the inner circumferential wall of the mounting cavity 18, providing stable support and reducing movement clearance, resulting in smoother and more stable rotation of the gear position ring 24. The inner circumference of the gear position ring 24 is provided with a second tooth, which is a mechanical interface for meshing with the transmission gear 25 to receive driving force from the drive shaft 23. The transmission gear 25, coaxially fixedly connected to the drive shaft 23, rotates synchronously with the drive shaft 23 and transmits rotational motion to the gear position ring 24. The transmission gear 25 and the second tooth achieve power transmission through gear meshing, ensuring that the rotation of the handwheel 22 can accurately drive the gear position ring 24 to rotate. The outer periphery of the gear position ring 24 is provided with multiple gear position marks, which can be numbers, symbols, or colors, visually indicating the different intensity levels currently set on the tensioner. A viewing window 26 is provided on one side of the housing 3; this window is a transparent or open area, allowing the user to observe the gear position marks on the gear position ring 24. When the gear position ring 24 rotates, one of the gear position marks will be precisely positioned in the viewing window 26, thus clearly indicating the currently selected intensity level.

[0064] With the above setup, when the user manually rotates the handwheel 22 to adjust the resistance level of the resistance band, the rotation of the handwheel 22 drives the transmission gear 25 to rotate via the transmission shaft 23. The transmission gear 25 meshes with the second tooth of the gear position ring 24, thereby driving the gear position ring 24 to rotate within the mounting cavity 18. As the gear position ring 24 rotates, different gear position markings on its outer peripheral wall pass sequentially through the viewing window 26 on the housing 3. When the user stops adjusting, the gear position marking corresponding to the currently selected resistance level will be clearly displayed in the viewing window 26. This allows the user to intuitively and accurately understand and set the resistance level of the resistance band, avoiding blind adjustment or guesswork based on experience, greatly improving the convenience and accuracy of manual adjustment, and ensuring the consistency and repeatability of training.

[0065] In one embodiment, such as Figure 9 and Figure 10This application further proposes an improved adjustment mechanism, the specific structure of which includes: a transmission component 6 is a tubular structure, a lead screw 9 is coaxially disposed in the transmission component 6, an annular gap is formed between the transmission component 6 and the lead screw 9, the end of the lead screw 9 away from the drive wheel 5 is rotatably connected to the end of the lead screw 9 away from the drive wheel 5, an anti-rotation groove 27 is coaxially disposed inside the lead screw 9, the anti-rotation component 11 is a square steel adapted to the anti-rotation groove 27, the end of the square steel is slidably connected in the anti-rotation groove 27 and fixedly connected to the housing 3, the axial stop nut 10 is a threaded sleeve structure with internal threads, installed in the active transmission groove 14 to save axial space of the housing 3, the outer diameter of the axial stop nut 10 is smaller than the inner diameter of the transmission component 6, the axial stop nut 10 extends into the transmission component 6 and is threadedly connected to the lead screw 9, the end of the axial stop nut 10 extends to the outside of the housing 3 for driving.

[0066] Specifically, the transmission component 6 adopts a tubular structure, meaning its interior is hollow, providing space for the coaxial arrangement of the lead screw 9. The lead screw 9 is coaxially positioned inside the transmission component 6, causing them to overlap axially rather than be parallel, thus significantly reducing the radial dimension of the adjustment mechanism and optimizing the utilization of axial space. The annular gap formed between the transmission component 6 and the lead screw 9 can be used to accommodate other components, further improving the structural integration.

[0067] The end of the lead screw 9 furthest from the drive wheel 5 is rotatably connected to the end of the transmission component 6 furthest from the drive wheel 5. This connection ensures that the lead screw 9 does not affect the rotation of the transmission component 6 when it cannot rotate on its own, and does not affect the transmission of torque by the transmission component 6. This connection is usually achieved through bearings or bushings to reduce friction and ensure smooth movement.

[0068] To prevent the lead screw 9 from rotating on its own axis, this application provides an anti-rotation groove 27 coaxially inside the lead screw 9. This anti-rotation groove 27 can be a non-circular inner hole, such as a square hole, a D-shaped hole, or a hole with a keyway. The anti-rotation component 11 is configured as a square steel piece adapted to the anti-rotation groove 27. One end of the square steel piece is slidably connected in the anti-rotation groove 27, meaning the lead screw can slide along the axial direction of the square steel piece but cannot rotate relative to it. The other end of the square steel piece is fixedly connected to the housing 3, thereby locking the rotation of the lead screw 9. This design ensures that the lead screw 9 itself does not rotate when moving axially, thus enabling gear adjustment by rotating the axial stop nut 10 to drive the lead screw 9 to move axially.

[0069] The axial locking nut 10 is designed as a threaded sleeve structure with internal threads that mate with the external threads of the lead screw 9. This threaded sleeve structure is cleverly installed in the drive drive groove 14. The drive drive groove 14 is typically located at the center of the drive wheel 5 and is used for transmission connection with the lead screw 9. Integrating the axial locking nut 10 into the drive drive groove 14 allows the structure of the nut and the drive wheel 5 to overlap axially, thereby effectively shortening the axial length of the entire tensioner, significantly saving axial space in the housing 3, and improving the compactness of the device.

[0070] The outer diameter of the axial locking nut 10 is designed to be smaller than the inner diameter of the transmission component 6, allowing the axial locking nut 10 to extend into the tubular transmission component 6. This nested structure further optimizes space utilization. While extending into the transmission component 6, the axial locking nut 10 still maintains a threaded connection with the lead screw 9, ensuring the axial movement function of the lead screw 9. This design not only saves axial space but also makes the entire adjusting mechanism more compact and integrated.

[0071] The end of the axial stop nut 10 extends outside the housing 3 to facilitate its driving operation. This means that the driving part of the axial stop nut 10 is located outside the housing 3, and it can be operated directly, either electrically or manually, to rotate the axial stop nut 10, thereby driving the lead screw 9 to move axially and achieve gear adjustment.

[0072] With the above configuration, the axial locking nut 10 is designed as a threaded sleeve structure and installed in the active transmission groove 14. Its outer diameter is smaller than the inner diameter of the transmission component 6 and extends into the transmission component 6. This highly integrated nested design greatly shortens the axial length of the entire tensioner, significantly saves valuable space inside the housing 3, and improves the portability of the tensioner. At the same time, the end of the axial locking nut 10 extends outside the housing 3. Overall, the above technical solution significantly improves the structural compactness of the anti-gear shifting tensioner, reduces its overall size, and makes the device easier to carry and deploy, without affecting the accuracy and stability of its adjustable gear.

[0073] In one embodiment, this application further proposes that a gear-shaped handwheel 28 is fixedly connected to the outer end of the axial locking nut 10 for easy manual operation. An electric unit is detachably connected to one end of the housing 3 near the gear-shaped handwheel 28. The electric unit includes an end cap 29, a servo motor 30, and a second drive gear 31. The servo motor 30 is connected to the gear-shaped handwheel 28 via the second drive gear 31. The end cap 29 is detachably connected to the end of the housing 3, covering the gear-shaped handwheel 28, the second drive gear 31, and the servo motor 30.

[0074] Specifically, the gear-shaped handwheel 28 fixedly connected to the outer end of the axial locking nut 10 is a component that combines the convenience of manual operation with the function of a mechanical transmission interface. Its gear-shaped shape allows users to directly adjust the force level by hand rotation, achieving intuitive and precise manual control. At the same time, its toothed structure provides a standardized meshing interface for subsequent electric drive, without requiring additional modifications to the axial locking nut 10 itself.

[0075] The electric unit, detachably connected to the end of housing 3 near the gear-shaped handwheel 28, is a modular electric drive assembly. This electric unit is designed for easy installation and removal, allowing users to switch between manual and electric drive modes as needed. This detachable design greatly improves the flexibility and maintainability of the equipment. The electric unit can be connected using various methods such as bolt fixing or snap-fit ​​connections to ensure a stable connection while maintaining ease of disassembly.

[0076] The electric drive unit internally includes an end cap 29, a servo motor 30, and a second drive gear 31. The end cap 29 is the outer shell of the electric drive unit, its main function being to protect the internal servo motor 30 and second drive gear 31 from external environmental factors (such as dust and moisture) and to provide structural support. The end cap 29 is typically made of lightweight and durable materials, and its shape and size match the end of the housing 3 for a seamless connection and a good appearance. The servo motor 30 is a motor capable of providing precise position, speed, and torque control. As the core power source for the electric drive, it is responsible for generating rotational torque to drive the axial stop nut 10. Choosing a servo motor ensures the accuracy of force adjustment and response speed. The second drive gear 31 is mounted on the output shaft of the servo motor 30, and its function is to transmit the rotational motion and torque of the servo motor 30 to the gear-shaped handwheel 28.

[0077] The servo motor 30 is connected to the gear-shaped handwheel 28 via a second drive gear 31, meaning that the second drive gear 31 and the gear-shaped handwheel 28 directly mesh, forming a simple gear transmission system. When the servo motor 30 rotates, it drives the gear-shaped handwheel 28 to rotate via the second drive gear 31, which in turn drives the axial stop nut 10 to move axially along the lead screw 9, thereby adjusting the force level. This direct transmission method has a compact structure and high transmission efficiency.

[0078] End cap 29 is detachably attached to the end of housing 3 and covers gear-shaped handwheel 28, second drive gear 31, and servo motor 30. This means that when the electric unit is installed, end cap 29 not only encloses the internal components of the electric unit (servo motor 30, second drive gear 31) but also covers the previously exposed gear-shaped handwheel 28. This design makes the entire electric drive system a complete and protected whole, ensuring the safety of the internal components and making the device look cleaner. When the electric unit is disassembled, the gear-shaped handwheel 28 is exposed again for easy manual operation by the user.

[0079] With the above configuration, the gear-shaped handwheel 28, fixedly connected to the outer end of the axial stop nut 10, not only provides users with a convenient manual drive method, but its gear structure also provides a standardized interface for subsequent electric drive. The detachably connected electric unit, including the end cover 29, servo motor 30, and second drive gear 31, can be connected to the gear-shaped handwheel 28 via the second drive gear 31, thereby realizing flexible switching between manual and electric drive methods and modular upgrades. In addition, this modular design reduces production costs and provides users with more flexible product choices, such as purchasing the manual version first and then upgrading to the electric version later as needed.

[0080] In one embodiment, this application further proposes that a rope outlet 32 ​​is provided on the side of the housing 3 corresponding to the drive wheel 5, and the pull rope 4 extends to the outside of the housing 3 through the rope outlet 32. When the electric unit is installed at the end of the housing 3, the center of gravity of the puller is close to the rope outlet 32. A strap 33 is provided on the side of the housing 3 facing away from the rope outlet 32 ​​to facilitate fixing the puller.

[0081] Specifically, the rope outlet 32 ​​located on the side of the housing 3 corresponding to the drive wheel 5 is an opening on the housing 3 for the pull rope 4 to extend out. Its location on the side of the housing 3, corresponding to the drive wheel 5, ensures that the pull rope 4 can be smoothly and unobstructedly extended from the drive wheel 5, facilitating stretching training for the user. The pull rope 4 extends to the outside of the housing 3 through this rope outlet 32, allowing the user to directly hold and operate the pull rope 4. When the electric unit is installed at the end of the housing 3, its weight affects the overall center of gravity of the resistance band. By designing the center of gravity of the resistance band closer to the rope outlet 32, the resistance band becomes more stable during use. For example, when the user pulls the pull rope 4, the direction of the force is relatively reasonable with the center of gravity, reducing the risk of the resistance band tipping over or wobbling, and improving operational stability and safety. The electric unit balances the weight of multiple driven wheels 7, bringing the center of gravity of the resistance band closer to the rope outlet 32, avoiding a top-heavy or bottom-heavy situation. Furthermore, the strap 33 is a flexible strip structure used to fix the resistance band in a specific position. Located on the side of the housing 3 opposite to the rope outlet 32, the strap 33 provides a counter-fixing force when the pull rope 4 is pulled, effectively preventing the resistance band from shifting under stress. The strap 33 can be in various forms such as Velcro, snaps, or loops, allowing users to easily attach it to pillars, fitness equipment, or other stable supports, thus enabling diverse training postures and scenarios and greatly improving the flexibility and safety of the resistance band.

[0082] With the above-described configuration, a rope outlet 32 ​​is provided on the side of the housing 3 corresponding to the drive wheel 5, allowing the pull rope 4 to extend outside the housing 3 through this outlet. This ensures the smoothness of the pull rope 4's path, reduces obstacles during use, and improves operational convenience. Simultaneously, when the electric unit is installed at the end of the housing 3, it can balance multiple passive wheels, bringing the center of gravity of the resistance band closer to the rope outlet 32. This makes the resistance band more stable under load, reducing the risk of tipping over and thus improving safety. Furthermore, a strap 33 is provided on the side of the housing 3 facing away from the rope outlet 32, providing a convenient way for users to secure the resistance band. This allows the resistance band to be firmly installed on various supports, greatly expanding training scenarios and postures, further enhancing the product's practicality and user experience.

[0083] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A tension resistor for preventing gear shifting, comprising a housing, a pull rope, a drive wheel, a transmission component, an adjustment mechanism, multiple driven wheels, and a spring. The drive wheel is rotatably connected to the housing, and the pull rope is wound around it. The multiple driven wheels are coaxially arranged with the drive wheel and rotatably connected to the housing. The spring is installed between the driven wheels and the housing. The transmission component enables transmission between the drive wheel and at least one driven wheel. The adjustment mechanism drives the transmission component to move axially to adjust the number of driven wheels engaged and the gear level. The tension resistor is characterized in that... The adjusting mechanism includes a lead screw, an axial stop nut, and an anti-rotation component. One end of the lead screw is rotatably connected to the transmission component and moves axially synchronously with the transmission component. The axial stop nut is threadedly connected to the lead screw and is rotatably installed in the housing. It is driven by electric or manual power. The anti-rotation component prevents the lead screw from rotating on its own.

2. The anti-gear shifting tensioner according to claim 1, characterized in that, The lead screw has a stop plane parallel to its own axis on its side. The anti-rotation component is a stop block, which is fixedly installed in the housing. It has a D-shaped hole that matches the lead screw, and the lead screw passes through the stop block through the D-shaped hole.

3. The anti-gear shifting tensioner according to claim 1, characterized in that, The driving wheel and the driven wheel are respectively provided with an active transmission groove and a driven transmission groove adapted to the transmission component at their center. One end of the transmission component is slidably connected to the active transmission groove on the same axis, and the other end extends into the driven transmission groove of at least one driven wheel.

4. The anti-gear shifting tensioner according to claim 3, characterized in that, Both the active transmission groove and the driven transmission groove are spline grooves. The outer periphery of the transmission component is provided with splines that are adapted to the spline groove. The end of the spline groove is provided with a first chamfer, and the end of the spline is provided with a second chamfer, so that the spline extends into the spline groove.

5. The anti-gear shifting tensioner according to claim 1, characterized in that, The housing has a mounting cavity on the side of the driven wheel away from the driving wheel. The rotating end of the lead screw is located at the end of the transmission component away from the driving wheel. The free end of the lead screw extends into the mounting cavity. The outer side of the axial stop nut is provided with a first tooth. A first drive gear is rotatably connected in the mounting cavity. The first drive gear meshes with the first tooth. When the axial stop nut is electrically driven, a DC motor, a displacement sensor, a controller, and a battery are installed in the mounting cavity. The DC motor is connected to the first drive gear and is controlled by the controller. The battery is used for power supply, and the displacement sensor is used to detect the axial movement distance of the lead screw. When the axial locking nut is manually driven, a handwheel is rotatably mounted on the end of the housing, and the handwheel is connected to the first drive gear through a transmission shaft.

6. The anti-gear shifting tensioner according to claim 5, characterized in that, When the axial stop nut is electrically driven, the controller integrates a wireless module, which can connect wirelessly to a mobile phone or remote control.

7. The anti-gear shifting tensioner according to claim 5, characterized in that, When the axial stop nut is manually driven, the inner peripheral wall of the mounting cavity is cylindrical, and a gear ring is rotatably connected inside the mounting cavity. The outer peripheral wall of the gear ring fits against the inner peripheral wall of the mounting cavity. The inner peripheral of the gear ring is provided with a second tooth. A transmission gear is coaxially fixedly connected to the transmission shaft. The transmission gear meshes with the second tooth. Multiple gear markings are provided on the outer peripheral of the gear ring. A viewing window is provided on one side of the housing, and one of the gear markings is located at the viewing window.

8. The anti-gear shifting tensioner according to claim 1, characterized in that, The transmission component is a tubular structure, with the lead screw coaxially disposed within it. An annular gap is formed between the transmission component and the lead screw. The end of the lead screw away from the drive wheel is rotatably connected to the end of the transmission component away from the drive wheel. An anti-rotation groove is coaxially disposed within the lead screw. The anti-rotation component is a square steel adapted to the anti-rotation groove. The end of the square steel is slidably connected in the anti-rotation groove and fixedly connected to the housing. The axial stop nut is a threaded sleeve structure with internal threads, installed in the active transmission groove to save axial space in the housing. The outer diameter of the axial stop nut is smaller than the inner diameter of the transmission component. The axial stop nut extends into the transmission component and is threadedly connected to the lead screw. The end of the axial stop nut extends outside the housing for driving.

9. The anti-gear shifting tensioner according to claim 8, characterized in that, The outer end of the axial stop nut is fixedly connected to a gear-shaped handwheel for easy manual drive. An electric unit is detachably connected to one end of the housing near the gear-shaped handwheel. The electric unit includes an end cover, a servo motor, and a second drive gear. The servo motor is connected to the gear-shaped handwheel via the second drive gear. The end cover is detachably connected to the end of the housing, covering the gear-shaped handwheel, the second drive gear, and the servo motor.

10. The anti-gear shifting tensioner according to claim 9, characterized in that, The side of the housing is provided with a rope outlet corresponding to the drive wheel. The pull rope extends to the outside of the housing through the rope outlet. When the electric unit is installed at the end of the housing, the center of gravity of the puller is close to the rope outlet. The side of the housing facing away from the rope outlet is provided with a strap to facilitate fixing the puller.

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