High-rigidity large-angle-range movement device for magnetic control robot

Abstract

The invention relates to the technical field of mechanical arms, and particularly discloses a high-rigidity large-angle-range movement device for a magnetic control robot. The parallel movement mechanism is provided with a static platform, a movable platform, an axial supporting rod, a two-section type main hinge and a plurality of two-section type auxiliary hinges. A sleeve piece is rotatably arranged on the static platform, and the two ends of the axial supporting rod are movably connected with the movable platform and the sleeve piece respectively; the head end of the two-section type main hinge is fixed to the sleeve piece, and the tail end of the two-section type main hinge is rotationally connected with the movable platform. The two-section type auxiliary hinge is rotatably arranged on the periphery of the sleeve piece, and the tail end of the two-section type auxiliary hinge is rotatably connected with the movable platform; the composite motion of the two-section type main hinge and the two-section type auxiliary hinge forms the output motion of the movable platform; according to the high-rigidity large-angle-range movement device for the magnetic control robot, a modularized parallel mechanism is adopted, high-rigidity large-angle-range movement of the mechanical arm can be achieved, and the stability and high precision of the tail end of the mechanical arm are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical arms, and in particular to a device for high-rigidity and large-angle range motion of a magnetically controlled robot. Background Art

[0002] The difficulty in designing a heavy-load, multi-degree-of-freedom magnetically controlled robot lies in requiring the robot to be able to move simultaneously in multiple dimensions, have sufficient strength and rigidity to withstand the load of a high-intensity magnetic field device, and ensure motion accuracy under heavy loads.

[0003] The angle range of traditional parallel robots is only about ±20°, which makes it difficult to achieve magnetically controlled adjustments within a large range. Collaborative robotic arms need to have a large range of activities to adjust the angle of the end, which can easily interfere with surrounding instruments and equipment in an operating room environment. In addition, the stiffness of the collaborative robot arm is poor. Under heavy loads, the stability and precision of the end of the robotic arm are low. For this reason, the present invention has developed a motion mechanism that combines strength, compactness, high stiffness / heavy load, and the ability to achieve posture adjustment within a large angle range in a small space, providing an equipment foundation for magnetically controlled vascular intervention. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device for high-rigidity and large-angle range motion of a magnetically controlled robot, which adopts a modular parallel mechanism as a whole to achieve high-rigidity and large-angle range motion of the magnetically controlled robot.

[0005] To solve the above problems, the present invention adopts the following technical solutions:

[0006] A device for high-rigidity and large-angle range motion of a magnetically controlled robot comprises: at least one parallel motion mechanism.

[0007] The at least one parallel motion mechanism comprises a static platform, a dynamic platform, an axial support rod, a two-section main hinge and a plurality of two-section secondary hinges.

[0008] The static platform is rotatably provided with a sleeve member, and both ends of the axial support rod are movably connected to the dynamic platform and the sleeve member respectively.

[0009] The first end of the two-section main hinge is fixedly connected to the sleeve member, and the second end of the two-section main hinge is rotatably connected to the moving platform.

[0010] The head ends of the plurality of two-section auxiliary hinges are rotatably arranged on the outer periphery of the sleeve member with the central axis of the sleeve member as the rotation axis, and the tail ends of the plurality of two-section auxiliary hinges are rotatably connected to the moving platform.

[0011] The two-stage main hinge and the multiple two-stage secondary hinges are all located on the moving platform between the static platforms, and the composite motion of the two-stage main hinge and the multiple two-stage secondary hinges constitutes the output motion of the moving platform.

[0012] The device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure further includes: a load connection seat and a first detection device.

[0013] The load connecting seat is used for assembling the load.

[0014] The first detection device is arranged between the load connection seat and at least one parallel motion mechanism, and the first detection device is used to detect the mass of the load.

[0015] The moving platform and the load connecting seat are both fixedly connected to the first detection device.

[0016] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, a connecting ring is provided on the back of the moving platform.

[0017] The two-section main hinge is provided with a first rotating shaft, and the first rotating shaft is rotatably connected to the connecting ring.

[0018] The two-section secondary hinge is provided with a second rotating shaft, and the second rotating shaft is rotatably connected to the connecting ring.

[0019] The connecting ring is provided with a second detection device for acquiring the rotation angle data of the first rotating shaft and / or the second rotating shaft.

[0020] In the device for high-rigidity and large-angle range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the two-section main hinge and the two-section secondary hinge both include: a collar and a hinge rod group.

[0021] The first end of the hinge rod assembly is configured to be fixedly connected to the collar.

[0022] The collar and the sleeve member form a concentric sleeve structure.

[0023] The first rotating shaft is rotatably disposed at the end of the hinge rod group of the two-stage main hinge, and the second rotating shaft is rotatably disposed at the end of the hinge rod group of the two-stage secondary hinge.

[0024] The second detection device is configured to be fixedly connected to the connecting ring.

[0025] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the two-section main hinge and the two-section secondary hinge both further include: a driving mechanism.

[0026] The driving mechanism is used for driving the collar to rotate.

[0027] The driving mechanism is configured to be fixedly connected to the static platform.

[0028] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the parallel motion mechanism further has an axial support rod.

[0029] The two ends of the axial support rod are respectively fixedly provided with a first universal joint and a second universal joint.

[0030] The axial support rod is movably connected to the moving platform via the first universal joint.

[0031] The axial support rod is movably connected to the sleeve member or the collar of the two-stage main hinge through the second universal joint.

[0032] When the axial support rod is perpendicular to the static platform, the central axes of the axial support rod and the sleeve member coincide with each other.

[0033] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the hinge rod group includes: a first curved rod and a second curved rod.

[0034] The second bent link is configured to be rotationally connected to the first bent link.

[0035] The first curved rod and the sleeve ring are integrally arranged, and the second curved rod is provided with an assembly hole, in which a rotating bearing is fixedly arranged.

[0036] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the first detection device is a pressure sensor, and the second detection device is an encoder.

[0037] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, a slot is provided on the moving platform, and the first universal joint is inserted into the slot.

[0038] The second universal joint is inserted into the sleeve member.

[0039] In the device for high-rigidity and large-angle-range motion of a magnetically controlled robot provided by at least one embodiment of the present disclosure, the driving mechanism includes a servo motor, a worm gear, and a transmission gear.

[0040] The output shaft of the servo motor is coupled to the worm, the transmission gear is sleeved outside the sleeve ring, and the worm is meshed with the transmission gear.

[0041] The central axis of the transmission gear coincides with the central axis of the collar.

[0042] The beneficial effects of the present invention are as follows: a modular design is adopted, and a plurality of parallel motion mechanisms can be used in a superimposed manner, thereby satisfying the high-rigidity and large-angle range motion of the magnetically controlled robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 This is a schematic diagram of the overall structure of the device for high-rigidity and large-angle range motion of the magnetically controlled robot in Example 1.

[0045] Figure 2 It is a connection diagram of the moving platform, the load connecting seat and the first detection device.

[0046] Figure 3 This is a schematic diagram of the connection between a two-section main hinge and two two-section secondary hinges.

[0047] Figure 4 Schematic diagram of the connection between a two-section main hinge and a single two-section secondary hinge.

[0048] Figure 5 Schematic diagram of the connection between two two-section secondary hinges.

[0049] Figure 6 It is a three-dimensional diagram of the axial support rod.

[0050] Figure 7 Schematic diagram of the distribution of a two-section main hinge, two two-section secondary hinges and a connecting ring.

[0051] Figure 8 It is a connection diagram between the connecting ring and the moving platform.

[0052] Fig. 9 This is a usage status diagram of the parallel motion mechanism in Example 2 after being connected in series.

[0053] Fig.10 Assembly diagram of the drive mechanism in Example 2.

[0054] Fig.11 Schematic diagram of transmission gear arrangement.

[0055] Fig.12 It is a three-dimensional exploded view of the sleeve member and the collar in Example 2.

[0056] In the figure:

[0057] 11. static platform; 12. dynamic platform; 13. axial support rod; 14. two-stage main hinge; 15. two-stage secondary hinge; 111. sleeve member; 112. tapered roller bearing; 121. slot; 122. connecting ring; 141. first rotating shaft; 142. sleeve ring; 143. hinge rod assembly; 151. second rotating shaft; 131. first universal joint; 132. second universal joint; 1431. first curved rod; 1432. second curved rod;

[0058] 20. Load connection socket;

[0059] 30. A first detection device;

[0060] 40. A second detection device;

[0061] 60. Driving mechanism; 61. Servo motor; 62. Worm; 63. Transmission gear. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments will be described clearly and completely below in conjunction with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0063] Example 1

[0064] like Figures 1 to 4 As shown, a device for high-rigidity and large-angle motion of a magnetically controlled robot includes: a parallel motion mechanism, a load connecting seat 20, a first detection device 30 and a second detection device 40.

[0065] Specifically, the parallel kinematic mechanism has a static platform 11 , a dynamic platform 12 , an axial support rod 13 , a two-stage main hinge 14 and a plurality of two-stage secondary hinges 15 .

[0066] Specifically, a sleeve member 111 is provided on the static platform 11, and a tapered roller bearing 112 is installed on the static platform 11. The static platform 11 and the sleeve member 111 are rotatably connected via the tapered roller bearing 112. The tapered roller bearing 112 brings a greater axial force capacity, ensuring that the sleeve member 111 has better movement ability.

[0067] Specifically, the front end of the two-stage main hinge 14 is fixedly connected to the sleeve member 111, and the rear end of the two-stage main hinge 14 is rotatably connected to the moving platform 12; the front ends of the two-stage auxiliary hinges 15 are rotatably arranged on the outer periphery of the sleeve member 111 with the central axis of the sleeve member 111 as the rotation axis, and the rear ends of the two-stage auxiliary hinges 15 are rotatably connected to the moving platform 12.

[0068] Specifically, the two-stage main hinge 14 and the multiple two-stage secondary hinges 15 are all located on the moving platform 12 between the static platform 11 , and the composite motion of the two-stage main hinge 14 and the multiple two-stage secondary hinges 15 constitutes the output motion of the moving platform 12 .

[0069] like Figure 3 and 7 As shown, in this embodiment, the back of the moving platform 12 has a connecting ring 122, and the second detection device 40 is configured to be fixedly connected to the connecting ring 122. The two-stage main hinge 14 is provided with a first rotating shaft 141, and the first rotating shaft 141 is rotatably connected to the connecting ring 122; the two-stage secondary hinge 15 is provided with a second rotating shaft 151, and the second rotating shaft 151 is rotatably connected to the connecting ring 122.

[0070] A second detection device 40 is provided on the connecting ring 122. The number of the second detection devices 40 can be configured according to demand, and the rotation angle data of the first rotating shaft 141 or the second rotating shaft 151 can be obtained, and the rotation angle data of the first rotating shaft 141 and the second rotating shaft 151 can even be obtained simultaneously.

[0071] Preferably, when the present embodiment needs to simultaneously obtain the rotation angle data of the first rotating shaft 141 and the second rotating shaft 151 , two sets of second detection devices 40 are required to obtain the rotation angle data of the first rotating shaft 141 and the second rotating shaft 151 , respectively.

[0072] Preferably, in the embodiment, there is one two-stage main hinge 14 and two two-stage secondary hinges 15 , then a total of three second detection devices 40 are needed, and the three second detection devices 40 respectively obtain the rotation angle data of the first rotating shaft 141 and the two second rotating shafts 151 .

[0073] It should be noted that the second detection device 40, the two-stage auxiliary hinge 15, and the second rotating shaft 151 can be selected in different quantities according to needs.

[0074] In this embodiment, the load connection base 20 is used to assemble the load, and the first detection device 30 is disposed between the load connection base 20 and the parallel motion mechanism. The first detection device 30 is used to detect the mass of the load. The moving platform 12 and the load connection base 20 are both fixedly connected to the first detection device 30.

[0075] In this embodiment, the first detection device 30 is a pressure sensor, and the second detection device 40 is an encoder.

[0076] The specific structures of the two-section main hinge 14 and the two-section secondary hinge 15 in this embodiment will be further disclosed below.

[0077] like Figures 3 to 5As shown, the two-section main hinge 14 and the two-section secondary hinge 15 both include a collar 142 and a hinge rod assembly 143 .

[0078] The first end of the hinge rod assembly 143 is configured to be fixedly connected to the collar 142 ; the collar 142 and the sleeve member 111 form a concentric sleeve structure.

[0079] The collar of the two-stage main hinge 14 is fixedly sleeved on the outer periphery of the sleeve member 111. The collars of the multiple two-stage secondary hinges 15 are rotatably sleeved on the outer periphery of the sleeve member 111 in sequence to form a concentric sleeve structure.

[0080] The collar of the two-stage main hinge 14 is located above the collar of the two-stage secondary hinge 15 , and the collar of the two-stage main hinge 14 plays a limiting role, thereby preventing the collar of the two-stage secondary hinge 15 from falling off.

[0081] The first rotating shaft 141 is rotatably disposed at the end of the hinge rod group 143 of the two-stage main hinge 14, and the second rotating shaft 151 is rotatably disposed at the end of the hinge rod group 143 of the two-stage secondary hinge 15. The first rotating shaft 141 and the second rotating shaft 151 are both coupled to their corresponding encoders.

[0082] The specific connection method among the movable platform 12, the sleeve member 111 and the axial support rod 13 in this embodiment will be further disclosed below.

[0083] like Figure 4 , 6 As shown in FIG. 8 , a first universal joint 131 and a second universal joint 132 are fixedly disposed at both ends of the axial support rod 13 .

[0084] Specifically, the axial support rod 13 is movably connected to the moving platform 12 via a first universal joint 131 ; the axial support rod 13 is movably connected to the collar of the two-stage main hinge 14 via a second universal joint 132 .

[0085] The second universal joint 132 is inserted into the collar 142 of the two-section main hinge 14 .

[0086] When the axial support rod 13 is perpendicular to the static platform 11 , the central axes of the axial support rod 13 and the sleeve member 111 coincide with each other.

[0087] The moving platform 12 is provided with a slot 121 , and the first universal joint 131 is inserted into the slot 121 .

[0088] The specific structure of the hinge rod assembly 143 in this embodiment will be further disclosed below.

[0089] like Figure 4 As shown, the hinge assembly 143 includes a first curved rod 1431 and a second curved rod 1432 ; the second curved rod 1432 is configured to be rotatably connected to the first curved rod 1431 .

[0090] The first curved rod 1431 and the collar 142 are integrally formed.

[0091] The second curved rod 1432 is provided with an assembly hole, in which a rotating bearing is fixedly arranged. The second curved rod 1432 uses the rotating bearing to realize the rotation connection with the first rotating shaft 141 and the second rotating shaft 151. The first rotating shaft 141 and the second rotating shaft 151 have high rotation accuracy and good rotation stability.

[0092] Example 2

[0093] like Figures 9 to 12 As shown, this embodiment provides a device for high-rigidity and large-angle range motion of a magnetically controlled robot, which is different from Embodiment 1 in that both the two-section main hinge 14 and the two-section secondary hinge 15 further include a driving mechanism 60 .

[0094] Specifically, the driving mechanism 60 is used to drive the collar 142 to rotate; the driving mechanism 60 is configured to be fixedly connected to the static platform 11 .

[0095] In this embodiment, the driving mechanism 60 includes a servo motor 61 , a worm 62 and a transmission gear 63 .

[0096] The output shaft of the servo motor 61 is coupled to the worm 62, the transmission gear 63 is sleeved outside the collar 142, and the worm 62 is meshed with the transmission gear 63; the central axis of the transmission gear 63 coincides with the central axis of the collar 142, the transmission gear 63 corresponding to the two-stage main hinge is fixedly connected to the sleeve member, and the transmission gear 63 corresponding to the two-stage secondary hinge is fixedly connected to its respective collar.

[0097] The diameter of the transmission gear 63 corresponding to the two-stage main hinge is smaller than the diameter of the transmission gear 63 corresponding to the two-stage auxiliary hinge 15, and the diameters of the transmission gears 63 corresponding to the two two-stage auxiliary hinges 15 are different; as a whole, it includes three stages of gears, which are respectively connected to three worm gears. This transmission method can increase the torque and make the mechanism have a self-locking function.

[0098] When in use, the servo motor 61 drives the transmission gear 63 to rotate, so that a two-stage main hinge and two two-stage secondary hinges rotate in coordination, so that the angle of the moving platform changes, and the moving platform can be moved in the two directions of "pitch and yaw", and the moving platform can be rotated around the axial direction of the sleeve part, with a total of three degrees of freedom. The three groups of drive devices cooperate with each other to realize the movement of the mechanism in two degrees of freedom. Since the purpose of this device is to drive a strong magnetic device with a large load at the top to achieve large-angle movement. Therefore, the axial direction of the device must have a high rigidity. By setting an axial support rod, it is prevented from being compressed along the axial direction during the process of driving the large load movement, thereby enhancing the axial rigidity of the device. The cooperation of the axial support rod and the universal joint can make the mechanism move synchronously with the three groups of connecting rod motion mechanisms.

[0099] like Fig. 9 As shown, when two parallel motion mechanisms are used in superposition, the moving platform of one parallel motion mechanism is fixedly connected to the static platform of another parallel motion mechanism and used in series to achieve a wider angle range of motion. The parallel motion mechanism has the characteristics of modular design. Multiple parallel motion mechanisms are connected end to end in sequence. While having higher rigidity and greater load, each modular parallel motion mechanism can be driven independently to achieve a wider angle range of motion. Therefore, installing a high-intensity focused magnetic field device at the load connection seat can achieve a wider range of magnetic control adjustment, which is convenient for the positioning and navigation of the magnetic control robot in medical surgery.

[0100] The encoder is used to feedback the motion angle and form a closed-loop control with the servo motor 61, thereby achieving accurate positioning of the device. The pressure sensor is used to measure the load mass and control the motor speed according to the obtained pressure value, thereby achieving precise control.

[0101] Real-time monitoring and feedback: By monitoring encoder and pressure sensor data in real time, the sensor data can help identify potential problems such as excessive torque, abnormal vibration or motion errors.

[0102] Example 3

[0103] This embodiment, which is not shown, provides a device for high-rigidity and large-angle range motion of a magnetically controlled robot, which is different from Embodiment 2 in that the driving mechanism includes a driving motor, a driving wheel, a driven wheel and a belt.

[0104] The output shaft of the driving motor is fixedly connected to the driving wheel, and the driving wheel and the driven wheel are linked through a belt.

[0105] The central axis of the driven wheel coincides with the central axis of the sleeve, the driven wheel corresponding to the two-stage main hinge is fixedly connected to the sleeve member, and the driven wheels corresponding to the two-stage secondary hinge are fixedly connected to their respective sleeves.

[0106] Example 3

[0107] This embodiment, not shown, provides a device for high-rigidity and large-angle range movement of a magnetically controlled robot. It differs from Embodiment 1 in that the second universal joint passes through the collar of the two-stage main hinge, and the axial support rod is movably connected to the sleeve member through the second universal joint.

[0108] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless explicitly stated, any elements, actions or instructions used in this document should not be interpreted as critical or necessary.

Claims

1. A device for high-rigidity and large-angle motion of a magnetically controlled robot, characterized in that: include: at least one parallel kinematic mechanism; Wherein, the at least one parallel kinematic mechanism comprises a static platform, a dynamic platform, a two-stage main hinge and a plurality of two-stage secondary hinges; The static platform is rotatably provided with a sleeve member; The first end of the two-stage main hinge is fixedly connected to the sleeve member, and the second end of the two-stage main hinge is rotatably connected to the moving platform; The head ends of the plurality of two-stage auxiliary hinges are rotatably arranged on the outer periphery of the sleeve member with the central axis of the sleeve member as the rotation axis, and the tail ends of the plurality of two-stage auxiliary hinges are rotatably connected to the moving platform; The two-stage main hinge and the multiple two-stage secondary hinges are all located on the moving platform between the static platforms, and the composite motion of the two-stage main hinge and the multiple two-stage secondary hinges constitutes the output motion of the moving platform.

2. A device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 1, characterized in that: Also includes: Load connection seat, used for assembling load; as well as A first detection device, disposed between the load connection seat and at least one parallel motion mechanism, the first detection device being used to detect the mass of the load; Wherein, the moving platform and the load connecting seat are both fixedly connected to the first detection device.

3. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 2, characterized in that: The back side of the moving platform is provided with a connecting ring; The two-stage main hinge is provided with a first rotating shaft, and the first rotating shaft is rotatably connected to the connecting ring; The two-stage secondary hinge is provided with a second rotating shaft, and the second rotating shaft is rotatably connected to the connecting ring; The connecting ring is provided with a second detection device for acquiring the rotation angle data of the first rotating shaft and / or the second rotating shaft.

4. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 3, characterized in that: The two-stage main hinge and the two-stage secondary hinge both include: collar; and A hinge rod assembly, the first end of which is configured to be fixedly connected to the collar; Wherein, the collar and the sleeve member form a concentric sleeve structure; The first rotating shaft is rotatably disposed at the end of the hinge rod group of the two-stage main hinge, and the second rotating shaft is rotatably disposed at the end of the hinge rod group of the two-stage secondary hinge; The second detection device is configured to be fixedly connected to the connecting ring.

5. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 4, characterized in that: The two-stage main hinge and the two-stage secondary hinge both further include: A driving mechanism, used for driving the collar to rotate; Wherein, the driving mechanism is configured to be fixedly connected to the static platform.

6. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 4, characterized in that: The parallel motion mechanism also has an axial support rod; The two ends of the axial support rod are respectively fixedly provided with a first universal joint and a second universal joint; The axial support rod is movably connected to the moving platform via the first universal joint; The axial support rod is movably connected to the sleeve member or the collar of the two-stage main hinge through the second universal joint; When the axial support rod is perpendicular to the static platform, the central axes of the axial support rod and the sleeve member coincide with each other.

7. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 4, characterized in that: The hinge rod assembly comprises: first crank; and a second curved rod, configured to be rotatably connected to the first curved rod; The first curved rod and the sleeve ring are integrally arranged, and the second curved rod is provided with an assembly hole, in which a rotating bearing is fixedly arranged.

8. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 3, characterized in that: The first detection device is a pressure sensor, and the second detection device is an encoder.

9. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 6, characterized in that: The moving platform is provided with a slot, and the first universal joint is inserted into the slot.

10. The device for high-rigidity and large-angle motion of a magnetically controlled robot according to claim 5, characterized in that: The driving mechanism includes a servo motor, a worm and a transmission gear; The output shaft of the servo motor is coupled with the worm, the transmission gear is sleeved outside the collar, and the worm is meshed with the transmission gear; The central axis of the transmission gear coincides with the central axis of the collar.

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