A rope-driven device based on mechanical programming

Abstract

This invention discloses a rope-driven device based on mechanical programming, belonging to the field of soft robot technology. The device mainly includes a moving part, a winding part, four linkage ropes, and four drive ropes. The moving part achieves mechanical switching of working modes by manually rotating and locking a long or short gear column, causing it to engage or disengage with the rack structure on the intermediate rack frame or top rack block. The winding part is driven by a single motor to wind the winding reel and release the linkage ropes, which, combined with the set mode, drive the moving part to produce corresponding actions, thereby controlling external actuators through the drive ropes. This invention, through an innovative mechanical programming structure, solidifies the motion logic into the mechanical structure, requiring only a single drive source to achieve independent and coordinated movement of multiple actuators. It has advantages such as simplified control system, compact structure, intuitive mode switching, and adjustable stroke, making it suitable for applications such as robot dexterity hands that require independent control of multiple joints.

Description

Technical Field

[0001] This invention relates to the field of soft robot technology, and in particular to a rope-driven device based on mechanical programming. Background Technology

[0002] Soft robots are a cutting-edge branch of robotics technology. They achieve active shape transformation through flexible actuation, giving them excellent adaptability and safety in human-robot interaction. This characteristic makes them promising for applications such as grasping fragile objects, precision assembly, medical rehabilitation assistance, and wearable assistive devices.

[0003] Rope actuation is an important form of flexible actuation. It transmits force and motion through the tension or slack of ropes, thereby driving distal joints or actuators to produce movements. This technology features simple structure, light weight, and the ability to remotely position drive motors, and has been widely used in recent years in fields such as robotic dexterous hands, bionic joints, and medical rehabilitation equipment.

[0004] However, existing rope-driven devices still have significant limitations in achieving stable and repeatable complex pre-programmed movements. For example, patent CN202511536180.X discloses a five-finger bionic dexterous hand with distributed tactile perception and its control method. Such rope-driven systems often rely on complex multi-motor collaborative control and high-precision real-time sensor feedback, resulting in high overall cost, complex control algorithms, and weak system anti-interference capabilities. Furthermore, to achieve independent flexion and extension movements of each finger, an independent motor is often required for each finger, further increasing the complexity of the structure and the control burden. In addition, such systems struggle to balance environmental adaptability with the determinism and repeatability of motion trajectories in flexible application scenarios. More importantly, their motion programs are generally implemented in the form of electronic code, which cannot be separated from complex controllers and sensor networks. Therefore, in special occasions requiring rapid deployment, high reliability, or resistance to electromagnetic interference, it is difficult to achieve intuitive, reliable, and easily switchable motion logic configuration. Summary of the Invention

[0005] This invention addresses the problems of high cost, complex algorithms, weak anti-interference capabilities, and large structural space occupation caused by complex electronic control systems in existing technologies. It proposes a rope-driven device based on mechanical programming. This device is suitable for scenarios requiring independent control of multiple remote joints or actuators, especially for driving the dexterous hand of a robot that performs four-finger collaborative operations. It can also be extended to other application scenarios with high requirements for structural integration and motion reliability.

[0006] This invention provides a rope-driven device based on mechanical programming, mainly comprising a moving part, a winding part, four linkage ropes, and four drive ropes. The linkage ropes connect the moving part and the winding part to achieve motion transmission and functional coordination between them. The drive ropes connect the moving part to an external actuator, such as a four-finger robot dexterity hand, thereby achieving stable drive of the external actuator. Through innovative mechanical programming structure integration, this device requires only a single drive source to coordinate and control the independent movement of multiple ropes, featuring a simple control system, compact structure, small space occupation, and minimal interference with the normal operation of external actuators.

[0007] The moving parts mainly include a bottom frame, four intermediate rack frames, four top rack blocks, four long gear columns, four short gear columns, eight springs, four long gear column locking blocks, four short gear column locking blocks, a shell, and multiple claw nails.

[0008] It should be noted that the bottom frame can be divided into four structurally similar and independent working spaces. Each working space has a slide rail structure at the bottom and on the left side. The middle rack frame has a "U" shaped structure, with corresponding sliding groove structures on its bottom outer wall and left outer wall. Through the cooperation of the slide rail and sliding groove structures, the four middle rack frames are respectively installed in the corresponding working spaces of the bottom frame, thereby restricting the freedom of the middle rack frames in the up, down, left, and right directions, ensuring that they can only achieve the expected sliding movement in the front-back direction. The bottom inner wall and left inner wall of the middle rack frame have slide rail structures, while the bottom and left side of the top rack block have corresponding sliding groove structures. Through the cooperation of the slide rail and sliding groove structures, the four top rack blocks are respectively installed on the corresponding middle rack frames, thereby restricting the freedom of the top rack blocks in the up, down, left, and right directions, so that they can only slide in the front-back direction.

[0009] It should be noted that each working space of the bottom frame is equipped with two springs. One spring is connected via a claw pin to the corresponding position of the right front outer wall of the intermediate rack frame and the front inner wall of the bottom frame, enabling automatic reset of the intermediate rack frame after displacement relative to the bottom frame. The other spring is connected via a claw pin to the left front inner wall of the intermediate rack frame and the front side of the top rack block, enabling reset of the top rack block relative to the intermediate rack frame after displacement. Simultaneously, a cylindrical structure is provided at the bottom of each working space of the bottom frame for mounting the long gear column. A cylindrical structure is also provided on the inner bottom side of the intermediate rack frame for mounting the short gear column. Both the long and short gear columns have incomplete gear structures at their bottoms and long strip structures extending along their length towards the teeth of the incomplete gear structure at their tops. A rack structure is provided on the right inner wall of the intermediate rack frame, and a rack structure is also provided on the right side of the top rack block. All four long gear columns and four short gear columns can be manually rotated to engage or disengage the long gear columns with the intermediate rack frame, and the short gear columns with the corresponding gear and rack structures of the top rack block. The top of the outer casing has four protruding structures, and the top of the intermediate rack frame also has protruding structures, for mounting the locking blocks of the long and short gear columns. The bottom of both the long and short gear column locking blocks has grooves corresponding to the long strip structures on the top of the long and short gear columns, used to lock them after they are rotated to the desired position. The outer casing is fixedly connected to the bottom frame with bolts to form an integral structure. When the incomplete gear structure of the long gear column engages with the rack structure of the intermediate rack frame, the installation of the long gear column locking blocks further restricts the relative displacement between the intermediate rack frame and the bottom frame. When the incomplete gear structure of the short gear column meshes with the rack structure of the top rack block, the installation of the short gear column locking block further restricts the relative displacement of the top rack block relative to the intermediate rack frame. Conversely, their relative displacements are not restricted. By pre-setting the rotation angles of the long and short gear columns in conjunction with the corresponding long and short gear column locking blocks, the device can switch between different operating modes to adapt to different motion function requirements. Furthermore, a claw nail is provided on the rear side of the top rack block for connecting the linkage rope, and thus connecting it to the winding section. A claw nail is provided on the left front outer wall of the intermediate rack frame, and a through hole is opened at the corresponding position on the bottom frame for connecting the drive rope, and thus connecting it to the external actuator.

[0010] It should be noted that the elongated block structure at the top of the long and short gear columns corresponds in length to the tooth direction of the incomplete gear at the bottom. This allows the operator to visually identify the current operating mode of the device by observing the direction of the elongated block, thus simplifying the mode switching and operation process.

[0011] It should be noted that, for ease of description and understanding of the present invention, the relevant orientations of the device are defined as follows: the end where the drive rope is located is defined as "front," the end where the linkage rope is located is defined as "rear," and the end where the bottom frame is located is defined as "down" or "bottom." Based on this, those skilled in the art can correspondingly understand and deduce orientations such as "left" or "right." Furthermore, the above orientation definitions are merely exemplary descriptions used to clearly illustrate the present invention and should not be construed as limiting the present invention.

[0012] The winding section includes a support frame, a motor, and a winding reel. The support frame secures the motor, and the motor output shaft is connected to the winding reel via a coupling. Four linkage ropes are wound around the winding reel. When the motor rotates forward, the winding reel winds up the linkage ropes, driving the moving part to perform corresponding actions in accordance with the set working mode. This, in turn, drives external actuators (such as different fingers of a four-finger robot's dexterous hand) to complete specific posture movements via the drive ropes. When the motor rotates in reverse, the linkage ropes are released, and under the elastic reset action provided by the eight springs, the moving part returns to its initial shape for the next work cycle. Thus, this device uses only a single drive source to achieve independent and coordinated movement of multiple actuators, significantly simplifying the control system and reducing the overall structural complexity.

[0013] It should be noted that there is no fixed rigid connection between the moving part and the winding part. They can be spatially separated according to actual installation needs, thereby reducing the structural volume of each installation position and avoiding interference with the normal movement of the external actuator. In addition, by adjusting the maximum allowable tensile length of the eight springs, the maximum rope drive stroke of the device can be adjusted accordingly, enabling it to adapt to external actuators with different stroke requirements and achieve the required action output.

[0014] Technical Effects: This invention embeds motion logic into mechanical components through an innovative mechanical programming structure, enabling independent and coordinated movement of multiple actuators with only a single motor drive. This significantly simplifies the control system, reduces overall cost, and enhances anti-interference capabilities. Furthermore, it offers reliable motion, intuitive mode switching, flexible modular arrangement, and adjustable drive stroke. It effectively avoids interference with external actuators and boasts broad stroke adaptability and ease of operation. Attached Figure Description

[0015] To clearly illustrate the technical solution of the present invention, the accompanying drawings involved in the embodiments will be briefly described below. It should be understood that the accompanying drawings are only schematic diagrams of some embodiments and are not intended to limit the present invention. Those skilled in the art can also obtain other embodiments based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of a rope drive device based on mechanical programming, provided in an embodiment of the present invention.

[0017] Figure 2 Schematic diagram I showing the detailed structure of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0018] Figure 3 Schematic diagram II showing the detailed structure of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0019] Figure 4 Exploded view I of the moving part of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0020] Figure 5 Partial exploded view II of the moving part of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the complete drive mode of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0022] Figure 7 A detailed schematic diagram of the complete drive mode of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0023] Figure 8 This is a schematic diagram of the completely non-drive mode of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0024] Figure 9 A detailed schematic diagram of the completely non-drive mode of the rope drive device based on mechanical programming provided in an embodiment of the present invention.

[0025] Labeling Explanation: 1. Moving Part; 101. Bottom Frame; 102. Middle Rack Frame; 103. Top Rack Block; 104. Long Gear Column; 105. Short Gear Column; 106. Spring; 107. Long Gear Column Locking Block; 108. Short Gear Column Locking Block; 109. Outer Shell; 110. Claw Nail; 2. Winding Part; 201. Support Frame; 202. Motor; 203. Winding Reel; 3. Linkage Rope; 4. Drive Rope. Detailed Implementation

[0026] The following will describe in detail specific embodiments of the present invention, examples of which are shown in the accompanying drawings. The same or similar reference numerals denote the same or similar elements, or elements having the same or similar functions. The following description in conjunction with the accompanying drawings is merely illustrative and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be noted that terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "outer," and "inner," which indicate direction or positional relationships, are defined based on the orientation or positional relationships shown in the accompanying drawings. Such definitions are only for the purpose of clearly describing the invention and simplifying the explanation, and should not be construed as limiting the invention. Furthermore, unless otherwise expressly defined, "a plurality of" in this invention means two or more.

[0028] The different embodiments or examples provided in this invention are used to illustrate possible structures and variations of the invention. For the sake of simplicity, specific components and their configurations in particular examples will be described in detail. It should be understood that these descriptions are merely illustrative and should not be construed as limiting the invention.

[0029] It should also be noted that the same reference numerals may be used repeatedly in different embodiments of the present invention, or some repetitive elements may be simplified. Such treatment is only for the purpose of pursuing conciseness and clarity of expression, and does not imply a specific relationship between the different implementation methods or structures, nor should it be construed as a limitation of the present invention.

[0030] Please see Figure 1 This invention provides a rope-driven device based on mechanical programming, mainly comprising a moving part 1, a winding part 2, four linkage ropes 3, and four drive ropes 4. The linkage ropes 3 connect the moving part 1 and the winding part 2, enabling motion transmission and functional coordination between them. The drive ropes 4 connect the moving part 1 to an external actuator (e.g., a four-finger robot dexterity hand), thereby stably transmitting motion to the external actuator. Through an innovative mechanical programming structure, this device requires only a single drive source to coordinate and control the independent movement of multiple ropes, featuring a simplified control system, compact structure, and minimal interference with the movement of external actuators.

[0031] See Figures 1 to 5The moving part 1 mainly includes a bottom frame 101, four intermediate rack frames 102, four top rack blocks 103, four long gear columns 104, four short gear columns 105, eight springs 106, four long gear column locking blocks 107, four short gear column locking blocks 108, a shell 109, and multiple claw nails 110. The bottom frame 101 can be divided into four structurally similar and independent working spaces, each with a slide rail structure at the bottom and on the left side. The intermediate rack frames 102 have a "U"-shaped structure, with corresponding sliding groove structures on their bottom outer wall and left outer wall. Through the interaction of the slide rails and sliding groove structures, the four intermediate rack frames 102 are respectively installed in the corresponding working spaces of the bottom frame 101, thereby restricting the freedom of the intermediate rack frames 102 in the up, down, left, and right directions, ensuring that they can only slide in the front-back direction. The bottom inner wall and left inner wall of the intermediate rack frame 102 are provided with slide rail structures, and the bottom and left side of the top rack block 103 are provided with corresponding slide groove structures. Through the cooperation of the slide rail and slide groove structures, the four top rack blocks 103 are respectively installed on the corresponding intermediate rack frame 102 to restrict the degree of freedom of the top rack blocks 103 in the up, down, left and right directions, so that they can only slide in the front and back directions.

[0032] See Figures 1 to 5Each working space of the bottom frame 101 is equipped with two springs 106. One spring 106 is connected by two claw pins 110 to the corresponding positions of the right front outer wall of the intermediate rack frame 102 and the front inner wall of the bottom frame 101, so as to achieve automatic reset after the intermediate rack frame 102 is displaced relative to the bottom frame 101. The other spring 106 is connected by two claw pins 110 to the left front inner wall of the intermediate rack frame 102 and the front side of the top rack block 103, so as to achieve automatic reset after the top rack block 103 is displaced relative to the intermediate rack frame 102. At the same time, a cylindrical structure (as indicated by dashed box I) is provided at the bottom of each working space of the bottom frame 101 for mounting the long gear column 104. A cylindrical structure (as indicated by dashed box II) is also provided on the bottom inner side of the intermediate rack frame 102 for mounting the short gear column 105. Both the long gear column 104 and the short gear column 105 have incomplete gear structures at their bottoms, and long strip blocks extending along their length towards the teeth of the incomplete gear structures at their tops. The inner right wall of the intermediate rack frame 102 has a rack structure, and the right side of the top rack block 103 also has a rack structure. The four long gear columns 104 and four short gear columns 105 can be manually rotated to engage or disengage the corresponding gear and rack structures of the long gear columns 104 and intermediate rack frame 102, and the short gear columns 105 and top rack block 103, respectively. The top of the outer casing 109 has four protruding structures (as indicated by dashed box III), and the top of the intermediate rack frame 102 also has protruding structures (as indicated by dashed box IV), used for mounting the long gear column locking blocks 107 and short gear column locking blocks 108, respectively. The bottom of both the long gear column locking block 107 and the short gear column locking block 108 is provided with grooves corresponding to the elongated block structures at the top of the long gear column 104 and the short gear column 105, for locking after the long gear column 104 and the short gear column 105 are rotated to the desired position. The outer casing 109 is fixedly connected to the bottom frame 101 by bolts to form an integral structure. When the incomplete gear structure of the long gear column 104 meshes with the rack structure of the intermediate rack frame 102, the installation of the long gear column locking block 107 further restricts the relative displacement between the intermediate rack frame 102 and the bottom frame 101. When the incomplete gear structure of the short gear column 105 meshes with the rack structure of the top rack block 103, the installation of the short gear column locking block 108 further restricts the relative displacement between the top rack block 103 and the intermediate rack frame 102. If they are not meshed, the corresponding displacement is unrestricted. By pre-setting the rotation angles of the long gear column 104 and the short gear column 105, and coordinating with the corresponding long gear column locking blocks 107 and short gear column locking blocks 108, the device can switch between different working modes to adapt to different motion function requirements. In addition, a ram's horn nail 110 is provided on the rear side of the top rack block 103 for connecting the linkage rope 3, and then connecting it to the winding part 2.The left front outer wall of the intermediate rack frame 102 is provided with a ram's horn nail 110, and the bottom frame 101 has a through hole at the corresponding position for connecting the drive rope 4, and then connecting it to the external actuator.

[0033] It should be noted that the elongated block structure at the top of the aforementioned long gear column 104 and short gear column 105 has its length direction corresponding to the tooth direction of the incomplete gear at the bottom. This allows the operator to intuitively identify the current working mode of the device by observing the direction of the elongated block, thereby simplifying the mode switching and operation process.

[0034] Please see Figures 1 to 3 The winding section 2 mainly includes a support frame 201, a motor 202, and a winding reel 203. The support frame 201 secures the motor 202, and the output shaft of the motor 202 is connected to the winding reel 203 via a coupling. Four linkage ropes 3 are wound around the winding reel 203. When the motor 202 rotates forward, the winding reel 203 winds up the linkage ropes 3, driving the motion section 1 to perform corresponding actions based on its set working mode. This, in turn, drives external actuators (such as different fingers of a four-finger robot's dexterous hand) to complete specific posture movements via the drive ropes 4. When the motor 202 rotates in the reverse direction, the linkage ropes 3 are released, and the motion section 1 returns to its initial state under the elastic reset action of eight springs 106, ready for the next work cycle. Therefore, this device only requires a single drive source to achieve independent and coordinated movement of multiple actuators, significantly simplifying the control system and reducing the overall structural complexity.

[0035] See Figures 1 to 7 Please refer to further information. Figure 6 and Figure 7 The long gear column 104 is rotated until its bottom incomplete gear structure disengages from the rack structure of the intermediate rack frame 102 (as indicated by dashed box V), and the long gear column locking block 107 is engaged to restrict further rotation. At this point, relative displacement can occur between the intermediate rack frame 102 and the bottom frame 101. Simultaneously, the short gear column 105 is rotated until its bottom incomplete gear structure engages with the rack structure of the top rack block 103 (as indicated by dashed box VI), and the short gear column locking block 108 is engaged to restrict further rotation, thereby constraining the relative displacement between the top rack block 103 and the intermediate rack frame 102, making them a linked whole. In this mode, when the motor 202 rotates forward, the winding reel 203 winds up the linkage rope 3, directly driving the intermediate rack frame 102 to move backward, which in turn drives the external actuator to produce corresponding actions (such as bending the fingers of the robot's dexterous hand) through the drive rope 4. When the motor 202 rotates in the reverse direction, the winding reel 203 releases the linkage rope 3. Under the reset action of the spring 106, the entire device returns to its initial state, making it easy to enter the next working cycle.

[0036] See Figures 1 to 9 Please refer to further information. Figure 8 and Figure 9 The long gear column 104 is rotated until its bottom incomplete gear structure meshes with the rack structure of the intermediate rack frame 102 (as indicated by dashed box VII), and the long gear column locking block 107 is engaged to restrict its further rotation. At this point, no relative displacement can occur between the intermediate rack frame 102 and the bottom frame 101. Simultaneously, the short gear column 105 is rotated until its bottom incomplete gear structure disengages from the rack structure of the top rack block 103 (as indicated by dashed box VIII), and the short gear column locking block 108 is engaged to restrict its continued rotation. At this point, relative sliding can occur between the top rack block 103 and the intermediate rack frame 102. In this mode, when the motor 202 rotates forward, the winding reel 203 winds up the linkage rope 3, causing only the top rack block 103 to slide backward. The intermediate rack frame 102 remains stationary, the drive rope 4 does not transmit driving force, and the posture of the external actuator remains unchanged (e.g., keeping the robot's dexterous hand fingers in a straight position). When the motor 202 rotates in the reverse direction, the winding reel 203 releases the linkage rope 3. Under the reset action of the spring 106, the entire device returns to its initial state so that the next working cycle can begin.

[0037] It should be noted that the above is only a specific example of the working mode of the motion part 1 of the present invention. Those skilled in the art should understand that other mode switching methods are also feasible. For example, by setting different mode states for each working space of the bottom frame 101, external actuators (such as the fingers of a robot's dexterous hand) can be driven to achieve simultaneous but different movements. For the sake of simplicity, further explanation is not provided here. In addition, there is no rigid connection between the motion part 1 and the winding part 2, and they can be spatially separated according to actual installation requirements, thereby reducing the structural volume of each installation position and avoiding interference with the normal movement of the external actuators. At the same time, by adjusting the maximum allowable tensile length of the spring 106, the maximum rope drive stroke of the device can be adjusted accordingly to adapt to external actuators with different stroke requirements and achieve the required action output.

[0038] In summary, although the present invention has been described in detail above with reference to specific embodiments, the scope of protection of the present invention is not limited thereto. Those skilled in the art can make various modifications, adjustments, or variations to the above embodiments without departing from the principles of the present invention, and all such modifications, adjustments, or variations should be covered within the scope of protection of the present invention.

Claims

1. A rope-driven device based on mechanical programming, characterized in that, include: The moving part (1), the winding part (2), the four linkage ropes (3) and the four drive ropes (4); the moving part (1) includes a bottom frame (101), four intermediate rack frames (102), four top rack blocks (103), four long gear columns (104), four short gear columns (105), eight springs (106), four long gear column locking blocks (107), four short gear column locking blocks (108), a shell (109) and multiple jackhammers (11) 0); The winding section (2) includes a support frame (201), a motor (202), and a winding reel (203); the support frame (201) is used to fix the motor (202), and the output shaft of the motor (202) is connected to the winding reel (203) through a coupling; the four linkage ropes (3) are wound on the winding reel (203); the linkage ropes (3) are connected to the top rack block (103) and the winding reel (203) through the ram's horn nail (110). 3) Between; the drive rope (4) is connected between the intermediate rack frame (102) and the external actuator via the spur (110); the spring (106) is connected between the intermediate rack frame (102) and the bottom frame (101) and between the top rack block (103) and the intermediate rack frame (102) via the spur (110) to provide a restoring force; the bottom of the long gear column (104) and the short gear column (105) is provided with It has an incomplete gear structure and a long strip block structure on the top; by manually rotating the long gear column (104) or the short gear column (105), the incomplete gear structure at the bottom can selectively engage or disengage with the rack structure on the intermediate rack frame (102) or the top rack block (103); by installing the long gear column locking block (107) or the short gear column locking block (108), the long gear column (104) or the short gear column (105) rotated to the expected position can be locked.

2. The rope drive device based on mechanical programming according to claim 1, characterized in that: The bottom frame (101) is divided into four independent working spaces, each of which contains one intermediate rack frame (102); the intermediate rack frame (102) is installed on the bottom frame (101) by means of a slide rail and a slide groove, and the top rack block (103) is installed on the intermediate rack frame (102) by means of a slide rail and a slide groove.

3. The rope drive device based on mechanical programming according to claim 1, characterized in that: The moving part (1) has at least two switchable working modes; in the first mode, the long gear column (104) disengages from the intermediate rack frame (102), the short gear column (105) meshes with the top rack block (103) and is locked, and when the motor (202) drives the winding reel (203) to wind the linkage rope (3), it drives the intermediate rack frame (102) to move, and then drives the external actuator to move through the drive rope (4); in the second mode, the long gear column (104) meshes with the intermediate rack frame (102) and is locked, the short gear column (105) disengages from the top rack block (103), and when the motor (202) drives the winding reel (203) to wind the linkage rope (3), it only drives the top rack block (103) to move, and the drive rope (4) does not drive the external actuator to move.

4. The rope drive device based on mechanical programming according to claim 1, characterized in that: There is no rigid connection between the moving part (1) and the winding part (2), and they can be arranged separately.

5. The rope drive device based on mechanical programming according to claim 1, characterized in that: The drive stroke of the drive rope (4) can be adjusted by adjusting the maximum allowable tensile length of the spring (106).

Images