A lifting device for deep sea fishery breeding platform

Abstract

The present invention provides a lifting device for a deep-sea fishery breeding platform, which includes a steel frame, a climbing device, a fixing device and a hydraulic cylinder; the hydraulic cylinder is extended, and because the upper end surface of the fixing pin is an inclined wedge surface, the fixing pin of the climbing device located above is retractable under the push of the hydraulic cylinder, and the fixing pin withdraws from the fixing hole, and the climbing device located above climbs upward; as the hydraulic cylinder continues to extend, the climbing device located above climbs upward through the fixing holes one by one, so that the breeding platform is lifted upward. When the hydraulic cylinder extends to the limit end, the hydraulic cylinder begins to recover, and because the fixing device makes the climbing device only have unidirectional movement ability, the climbing device located above cannot move downward, and under the action of the recovery force of the hydraulic cylinder, the climbing device located below climbs upward. As the hydraulic cylinder repeatedly stretches and contracts, the climbing device above and the climbing device below climb upward alternately, achieving the effect of the breeding platform automatically climbing upward.

Description

Technical Field

[0001] The invention relates to the technical field of lifting equipment, and in particular to a lifting device for a deep-sea fishery breeding platform. Background Art

[0002] The advantage of offshore aquaculture going to deep sea is that it has a wider aquaculture area compared to offshore shallow water aquaculture; seawater has high fluidity under the action of ocean currents and is richer in natural food for farmed fish; greater water depth increases the effective aquaculture water space per unit water surface. During the construction of deep-sea aquaculture platforms, the aquaculture platforms need to be higher than the sea surface for a certain distance to reduce the erosion of seawater on the aquaculture platforms and the impact of waves on the aquaculture personnel on the aquaculture platforms. The existing method of lifting aquaculture platforms mainly relies on ships with lifting capabilities to lift the platforms. Due to the influence of waves on the sea surface, lifting operations are very difficult. Summary of the invention

[0003] The technical problem to be solved by the present invention is: the present invention provides a lifting device for a deep-sea fishery aquaculture platform, which can realize the self-climbing of the aquaculture platform.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A lifting device for deep-sea fishery aquaculture platform, comprising a steel frame, a climbing device, a fixing device and a hydraulic cylinder;

[0006] The climbing devices include two, the two climbing devices are arranged on the steel frame from top to bottom and are slidably connected to the steel frame, the two ends of the hydraulic cylinder are respectively hinged on the two different climbing devices, and the fixing device is installed on the climbing device to fix the climbing device at the position of the steel frame;

[0007] The steel frame is provided with fixing holes at equal intervals in the vertical direction;

[0008] The fixing device includes a spring, a fixing pin and a limit pin, the fixing pin can be slidably arranged in the mounting hole on the climbing device and is adapted to the fixing hole, the limit pin is fixedly arranged on the body of the fixing pin, and the virtual axis of the limit pin is perpendicular to the virtual axis of the fixing pin, the spring is sleeved on the fixing pin, one end of the spring is connected to the limit pin, and the other end of the spring is connected to the end face of the mounting hole of the climbing device;

[0009] An inclined wedge surface is provided at one end of the fixing pin close to the steel frame, and the inclined wedge surface is arranged to face upward.

[0010] The beneficial effects of the present invention are as follows: the present invention provides a lifting device for a deep-sea fishery breeding platform, comprising a steel frame, a climbing device, a fixing device and a hydraulic cylinder; the hydraulic cylinder is extended, and because the upper end surface of the fixing pin is an inclined wedge surface, the fixing pin of the climbing device located above has a yielding property under the push of the hydraulic cylinder, and the fixing pin withdraws from the fixing hole, and the climbing device located above climbs upward until it moves to the next fixing hole, and the fixing pin is reset and inserted into the fixing hole for fixing; as the hydraulic cylinder continues to extend, the climbing device located above climbs upward through each fixing hole, so that the breeding platform is lifted upward. When the hydraulic cylinder extends to the limit end, the hydraulic cylinder begins to recover, and because the fixing device makes the climbing device only have unidirectional movement ability, the climbing device located above cannot move downward, and under the action of the recovery force of the hydraulic cylinder, the climbing device located below climbs upward. As the hydraulic cylinder repeatedly stretches and contracts, the climbing device above and the climbing device below alternately climb upward, achieving the effect of the breeding platform automatically climbing upward. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The figure shows a first structural schematic diagram of a lifting device for a deep-sea fishery farming platform according to an embodiment of the present invention;

[0012] Figure 2 It is a second structural schematic diagram of a lifting device for a deep-sea fishery farming platform according to an embodiment of the present invention;

[0013] Figure 3 The figure shows a schematic structural diagram of a climbing device used for a deep-sea fishery farming platform lifting device according to an embodiment of the present invention;

[0014] Figure 4 The figure shows a front view of a climbing device for a deep-sea fishery farming platform lifting device according to an embodiment of the present invention;

[0015] Figure 5 Shown Figure 4 Middle AA view;

[0016] Figure 6 The figure shows a schematic structural diagram of a platform stabilizing device for a deep-sea fishery aquaculture platform lifting device according to an embodiment of the present invention;

[0017] Figure 7 The figure shows a front view of a platform stabilizing device for a deep-sea fishery farming platform lifting device according to an embodiment of the present invention;

[0018] Figure 8 The figure shows a cross-sectional view of a platform stabilizing device for a deep-sea fishery farming platform lifting device according to an embodiment of the present invention;

[0019] Fig. 9The figure shows a schematic structural diagram of a lap joint auxiliary device for a deep-sea fishery farming platform lifting device according to an embodiment of the present invention;

[0020] Description of labels:

[0021] 1. Steel frame; 2. Climbing device; 3. Hydraulic cylinder; 4. Fixing hole; 5. Spring; 6. Fixing pin; 7. Limit pin; 8. Connecting rod; 9. Fixing ring; 10. Driving motor; 11. Worm; 12. Worm gear; 13. Driving shaft; 14. Clamping motor; 15. Screw; 16. Slide; 17. Chuck; 18. Pulley; 19. Breeding platform. DETAILED DESCRIPTION

[0022] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0023] Please refer to Figures 1 to 9 , a lifting device for deep-sea fishery aquaculture platform, comprising a steel frame, a climbing device, a fixing device and a hydraulic cylinder;

[0024] The climbing devices include two, the two climbing devices are arranged on the steel frame from top to bottom and are slidably connected to the steel frame, the two ends of the hydraulic cylinder are respectively hinged on the two different climbing devices, and the fixing device is installed on the climbing device to fix the climbing device at the position of the steel frame;

[0025] The steel frame is provided with fixing holes at equal intervals in the vertical direction;

[0026] The fixing device includes a spring, a fixing pin and a limit pin, the fixing pin can be slidably arranged in the mounting hole on the climbing device and is adapted to the fixing hole, the limit pin is fixedly arranged on the body of the fixing pin, and the virtual axis of the limit pin is perpendicular to the virtual axis of the fixing pin, the spring is sleeved on the fixing pin, one end of the spring is connected to the limit pin, and the other end of the spring is connected to the end face of the mounting hole of the climbing device;

[0027] An inclined wedge surface is provided at one end of the fixing pin close to the steel frame, and the inclined wedge surface is arranged to face upward.

[0028] From the above description, it can be seen that the beneficial effects of the present invention are as follows: the present invention provides a lifting device for deep-sea fishery aquaculture platform, including a steel frame, a climbing device, a fixing device and a hydraulic cylinder; the hydraulic cylinder is extended, and because the upper end surface of the fixing pin is an inclined wedge surface, the fixing pin of the climbing device located above has a yielding property under the push of the hydraulic cylinder, and the fixing pin withdraws from the fixing hole, and the climbing device located above climbs upward until it moves to the next fixing hole, and the fixing pin is reset and inserted into the fixing hole for fixing; as the hydraulic cylinder continues to extend, the climbing device located above climbs upward one by one through the fixing holes, so that the aquaculture platform is lifted upward. When the hydraulic cylinder extends to the limit end, the hydraulic cylinder begins to recover, and because the fixing device makes the climbing device only have unidirectional movement ability, the climbing device located above cannot move downward, and under the action of the recovery force of the hydraulic cylinder, the climbing device located below climbs upward. As the hydraulic cylinder repeatedly stretches and contracts, the climbing device above and the climbing device below alternately climb upward, achieving the effect of the aquaculture platform automatically climbing upward.

[0029] Furthermore, the upper side of the inner wall of the fixing hole is an inclined wedge surface.

[0030] From the above description, it can be seen that the upper side of the inner wall of the fixing hole is an inclined wedge surface, which can make the fixing pin of the climbing device have better yieldability during the ascent process, thereby reducing the climbing resistance.

[0031] Furthermore, the cross section of the steel frame is an I-shape;

[0032] The climbing device is provided with a mounting groove which is adapted to the cross-sectional shape of the steel frame.

[0033] From the above description, it can be seen that the cross-section of the steel frame is set to be I-shaped. On the one hand, the I-shaped cross-section has good structural strength and rigidity; on the other hand, the I-shaped cross-section can better fix the climbing device circumferentially.

[0034] Furthermore, it also includes a platform stabilizing device and a controller, wherein the controller is electrically connected to the platform stabilizing device;

[0035] The breeding platform and the climbing device located above are connected via the platform stabilizing device.

[0036] From the above description, it can be seen that since a breeding platform is provided with multiple steel frames, the climbing devices on the multiple steel frames need to work simultaneously, and the platform stabilizing device can realize the autonomous adjustment of the level of the breeding platform to compensate for the error of the inconsistent climbing pace of the climbing devices on different steel frames; secondly, the platform stabilizing device can also adjust the shaking of the breeding platform caused by the waves to ensure that the breeding platform is on a horizontal plane.

[0037] Furthermore, the platform stabilizing device comprises three sets of actuators and a fixing ring, wherein the three sets of actuators are arranged around the virtual axis of the fixing ring at equal angles and are respectively hinged to the bottom of the fixing ring;

[0038] The top of the fixing ring is fixedly connected to the lower surface of the breeding platform;

[0039] Each set of the actuator components includes a driving motor, a worm, a worm wheel, a driving shaft and a connecting rod. The main body of the driving motor is fixedly arranged on the upper surface of the climbing device. The output shaft of the driving motor is coaxially and fixedly connected with one end of the worm. The worm wheel is rotatably arranged on the climbing device, and the rotation axis is coaxially arranged with the virtual axis of the fixing ring. The worm is meshingly connected with the worm wheel. The upper end surface of the worm wheel is coaxially and fixedly connected with the lower end of the driving shaft. The upper end of the driving shaft is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the fixing ring. The driving motor is electrically connected to the controller.

[0040] From the above description, it can be seen that the platform stabilizing device adopts a parallel mechanism to achieve the stabilizing effect of the breeding platform, and the power output mechanism adopts a worm gear. The transmission structure has a large load-bearing capacity, smooth transmission, and self-locking ability to ensure the reliability of transmission.

[0041] Further, it also includes a splicing auxiliary device;

[0042] The overlapping auxiliary device is fixedly arranged on the breeding platform to assist the overlapping of the steel frame.

[0043] From the above description, it can be seen that as the breeding platform continues to rise, the steel frames need to be overlapped, and the overlap auxiliary device can assist the connection between the steel frames and improve the overlap efficiency of the steel frames.

[0044] Further, the overlapping auxiliary device includes a clamping motor, a screw, two sets of slides and two sets of chucks;

[0045] The main body of the clamping motor is fixedly arranged on the breeding platform, the output shaft of the clamping motor is coaxially fixedly connected to one end of the screw, the threads at both ends of the screw have opposite rotation directions, the two sets of slides are respectively screwed to the two ends of the screw, and the two sets of chucks are respectively fixedly arranged on the corresponding two sets of slides.

[0046] From the above description, it can be seen that a compound screw device is adopted, and the clamping motor drives the screw to rotate. Since the threads at both ends rotate in opposite directions, the chucks can move towards each other or away from each other, with a simple structure and convenient operation.

[0047] Furthermore, the chuck is provided with a plurality of pulleys;

[0048] The virtual rotation axis of the pulley is perpendicular to the virtual rotation axis of the screw rod and perpendicular to the virtual plane where the steel frame is located, and the pulleys on the two sets of chucks are arranged opposite to each other.

[0049] From the above description, it can be seen that the setting of the pulley can reduce the friction when the steel frame is lowered and docked, thereby reducing movement obstacles.

[0050] Furthermore, the hydraulic cylinder includes a plurality of hydraulic cylinders, and the plurality of hydraulic cylinders are arranged at intervals between two different climbing devices.

[0051] From the above description, it can be seen that providing multiple hydraulic cylinders can enable each hydraulic cylinder to share a smaller lifting force, thereby reducing the working pressure of the hydraulic cylinders.

[0052] Please refer to Figures 1 to 9 , Embodiment 1 of the present invention is:

[0053] A lifting device for deep-sea fishery aquaculture platform, comprising a steel frame 1, a climbing device 2, a fixing device and a hydraulic cylinder 3; during the climbing process of the aquaculture platform 19, the hydraulic cylinder 3 extends, and since the upper end surface of the fixing pin 6 is an inclined wedge surface, the climbing device 2 located at the top is lifted and pushed by the hydraulic cylinder 3, and the fixing pin 6 withdraws from the fixing hole 4, and the climbing device 2 located at the top climbs upward until it moves to the next fixing hole 4, and the fixing pin 6 is reset and inserted into the fixing hole 4 through the limit pin 7 under the action of the restoring force of the spring 5; as the hydraulic cylinder 3 continues to extend, the climbing device 2 located at the top climbs up one by one through the fixing holes 4, so that the aquaculture platform 19 is lifted upward. When the hydraulic cylinder 3 extends to the limit end, the hydraulic cylinder 3 begins to retract, and since the fixing device makes the climbing device 2 only have unidirectional movement ability, the climbing device 2 located at the top cannot move downward, and under the action of the recovery force of the hydraulic cylinder 3, the climbing device 2 located at the bottom climbs upward. As the hydraulic cylinder 3 reciprocates in telescopic motion, the upper climbing device 2 and the lower climbing device 2 alternately climb upward.

[0054] Preferably, a plurality of fixing devices are arranged on the climbing device 2. Specifically, the upper climbing device 2 needs to bear the load of the breeding platform 19 for a long time, so two fixing devices are arranged on the upper climbing device 2. One fixing device is arranged on the lower climbing device 2.

[0055] The breeding platform 19 is supported by a plurality of steel frames 1, each of which is provided with a climbing device 2. The cross section of the steel frame 1 is an I-shaped one, and the climbing device 2 is provided with a mounting groove adapted to the cross section shape of the steel frame 1, and the climbing device 2 is sleeved on the I-shaped steel frame 1. In order to ensure good mobility of the climbing device 2 and the steel frame 1, a ball bearing can be provided in the mounting groove of the climbing device 2 and butter can be added.

[0056] Please refer to Figure 3Specifically, in order to allow the fixing pin 6 to be better withdrawn from the fixing hole 4 during the climbing process, the upper side of the inner wall of the fixing hole 4 is configured as an inclined wedge surface.

[0057] Please refer to Figure 1 and Figure 2 Specifically, the hydraulic cylinder 3 includes two hydraulic cylinders 3, which are respectively arranged on different two side surfaces of the climbing device 2. The arrangement of the two hydraulic cylinders 3 can reduce the working power of a single hydraulic cylinder 3.

[0058] Please refer to Figures 6 to 8 , Embodiment 2 of the present invention is: Based on Embodiment 1, this embodiment further includes a platform stabilizing device and a controller, and the controller is electrically connected to the platform stabilizing device; the breeding platform 19 and the climbing device 2 located above are connected through the platform stabilizing device.

[0059] Specifically, the platform stabilizing device includes three sets of actuators and a fixed ring 9, the three sets of actuators are arranged around the virtual axis of the fixed ring 9 at equal angles, and are respectively hinged to the bottom of the fixed ring 9;

[0060] The top of the fixing ring 9 is fixedly connected to the lower surface of the breeding platform 19;

[0061] Each set of actuator components includes a drive motor 10, a worm 11, a worm wheel 12, a drive shaft 13 and a connecting rod 8. The main body of the drive motor 10 is fixedly arranged on the upper surface of the climbing device 2. The output shaft of the drive motor 10 is coaxially fixedly connected to one end of the worm 11. The worm wheel 12 is rotatably arranged on the climbing device 2, and the rotation axis is coaxially arranged with the virtual axis of the fixed ring 9. The worm 11 is meshingly connected with the worm wheel 12. The upper end face of the worm wheel 12 is coaxially fixedly connected to the lower end of the drive shaft 13. The upper end of the drive shaft 13 is hinged to one end of the connecting rod 8, and the other end of the connecting rod 8 is hinged to the fixed ring 9. The drive motor 10 is electrically connected to the controller. Among them, the three worm wheels 12 are coaxially stacked and rotatably arranged, the three drive shafts 13 are coaxially rotatably sleeved, and the bottoms of the three drive shafts 13 are respectively fixedly connected to the end faces of the three worm wheels 12.

[0062] Specifically, the drive motor 10 is used to compensate the motion error of the breeding platform 19. The implementation method is as follows: first, the electronic gyroscope and accelerometer are used to detect the direction and strength of the movement of the breeding platform 19, and then the processor in the controller calculates and analyzes the angles that each drive motor 10 needs to rotate, and finally the purpose of motion compensation is achieved by rotating the three drive motors 10. Specifically, the motion compensation algorithm is not described in detail here.

[0063] Please refer to Figure 1 , Figure 2 and Fig. 9, Embodiment 3 of the present invention is: based on Embodiment 1 or Embodiment 2, this embodiment further includes a lap joint assisting device, which is fixedly arranged on the breeding platform 19 to assist the lap joint of the steel frame 1.

[0064] Specifically, the overlap auxiliary device includes a clamping motor 14, a screw 15, two sets of slides 16 and two sets of chucks 17;

[0065] The main body of the clamping motor 14 is fixedly arranged on the breeding platform 19, the output shaft of the clamping motor 14 is coaxially fixedly connected with one end of the screw 15, the threads of the two ends of the screw 15 are rotated in opposite directions, the two sets of slides 16 are respectively screwed to the two ends of the screw 15, and the two sets of chucks 17 are respectively fixedly arranged on the corresponding two sets of slides 16. Preferably, the thread lifting of the screw 15 is less than the equivalent friction angle, so that it has self-locking property.

[0066] Specifically, when it is necessary to overlap the steel frame 1, the steel frame 1 to be overlapped is inserted between the two chucks 17. The two chucks 17 can provide good preload and guiding effect, especially when working on a shaking breeding platform 19. The overlapping auxiliary device can provide a good guiding effect and improve the overlapping efficiency of the steel frame 1. In order to better guide the steel frame 1, a plurality of pulleys 18 are provided on the chuck 17; the virtual rotation axis of the pulley 18 is perpendicular to the virtual rotation axis of the screw 15, and perpendicular to the virtual plane where the steel frame 1 is located, and the pulleys 18 on the two sets of chucks 17 are arranged opposite to each other. Preferably, the pulley 18 is made of rubber material with good anti-slip performance.

[0067] Specifically, the overlapping steel frames 1 are fixed with screws, one end of the steel frame 1 is provided with a mounting groove, and the other end is provided with a mounting pin. Two different steel frames 1 have the mounting pin of one steel frame 1 inserted into the mounting groove of the other steel frame 1, and then the two steel frames 1 are fixed with screws.

[0068] In summary, the lifting device for deep-sea fishery aquaculture platform provided by the present invention has the following advantages:

[0069] 1. The present invention provides a lifting device for a deep-sea fishery breeding platform. As the hydraulic cylinder repeatedly extends and retracts, the upper climbing device and the lower climbing device alternately climb upward, thereby achieving the effect of the breeding platform automatically climbing upward. The climbing process does not require external assistance, and the climbing height is not limited by the working stroke of the hydraulic cylinder.

[0070] 2. The present invention is provided with a platform stabilizing device. Since a breeding platform is provided with multiple steel frames, the climbing devices on the multiple steel frames need to work simultaneously. The platform stabilizing device can realize the autonomous adjustment of the level of the breeding platform to compensate for the error of the inconsistent climbing pace of the climbing devices on different steel frames; secondly, the platform stabilizing device can also adjust the shaking of the breeding platform caused by the waves to ensure that the breeding platform is on a horizontal plane.

[0071] 3. The platform stabilizing device of the present invention adopts a parallel mechanism to achieve the stabilizing effect of the breeding platform, and the power output mechanism adopts a worm gear. The transmission structure has a large load-bearing capacity, stable transmission, and self-locking ability, thereby ensuring the reliability of transmission.

[0072] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A lifting device for deep sea fishery aquaculture platform, characterized in that: It includes steel frame, climbing device, fixing device and hydraulic cylinder; The climbing devices include two, the two climbing devices are arranged on the steel frame from top to bottom and are slidably connected to the steel frame, the two ends of the hydraulic cylinder are respectively hinged on the two different climbing devices, and the fixing device is installed on the climbing device to fix the climbing device at the position of the steel frame; The steel frame is provided with fixing holes at equal intervals in the vertical direction; The fixing device includes a spring, a fixing pin and a limit pin, the fixing pin can be slidably arranged in the mounting hole on the climbing device and is adapted to the fixing hole, the limit pin is fixedly arranged on the body of the fixing pin, and the virtual axis of the limit pin is perpendicular to the virtual axis of the fixing pin, the spring is sleeved on the fixing pin, one end of the spring is connected to the limit pin, and the other end of the spring is connected to the end face of the mounting hole of the climbing device; The fixing pin is provided with an inclined wedge surface at one end close to the steel frame, and the inclined wedge surface is arranged upward; The upper side of the inner wall of the fixing hole is an inclined wedge surface; Also included is a platform stabilizing device and a controller, wherein the controller is electrically connected to the platform stabilizing device; The breeding platform and the climbing device located above are connected via the platform stabilizing device; The platform stabilizing device comprises three sets of actuators and a fixed ring, wherein the three sets of actuators are arranged around the virtual axis of the fixed ring at equal angles and are respectively hinged to the bottom of the fixed ring; The top of the fixing ring is fixedly connected to the lower surface of the breeding platform; Each set of the actuator components includes a driving motor, a worm, a worm wheel, a driving shaft and a connecting rod. The main body of the driving motor is fixedly arranged on the upper surface of the climbing device. The output shaft of the driving motor is coaxially and fixedly connected with one end of the worm. The worm wheel is rotatably arranged on the climbing device, and the rotation axis is coaxially arranged with the virtual axis of the fixing ring. The worm is meshingly connected with the worm wheel. The upper end surface of the worm wheel is coaxially and fixedly connected with the lower end of the driving shaft. The upper end of the driving shaft is hinged to one end of the connecting rod, and the other end of the connecting rod is hinged to the fixing ring. The driving motor is electrically connected to the controller.

2. The lifting device for deep sea fishery aquaculture platform according to claim 1, characterized in that: The cross section of the steel frame is an I-shape; The climbing device is provided with a mounting groove which is adapted to the cross-sectional shape of the steel frame.

3. The lifting device for deep sea fishery aquaculture platform according to claim 1, characterized in that: It also includes a lap joint assisting device, which is fixedly arranged on the breeding platform to assist the lap jointing of the steel frame.

4. The lifting device for deep sea fishery aquaculture platform according to claim 3 is characterized in that: The overlapping auxiliary device comprises a clamping motor, a screw rod, two sets of slides and two sets of chucks; The main body of the clamping motor is fixedly arranged on the breeding platform, the output shaft of the clamping motor is coaxially fixedly connected to one end of the screw, the threads at both ends of the screw have opposite rotation directions, the two sets of slides are respectively screwed to the two ends of the screw, and the two sets of chucks are respectively fixedly arranged on the corresponding two sets of slides.

5. The lifting device for deep sea fishery aquaculture platform according to claim 4, characterized in that: The chuck is provided with a plurality of pulleys; The virtual rotation axis of the pulley is perpendicular to the virtual rotation axis of the screw rod and perpendicular to the virtual plane where the steel frame is located, and the pulleys on the two sets of chucks are arranged opposite to each other.

6. The lifting device for deep sea fishery aquaculture platform according to claim 1, characterized in that: The hydraulic cylinders include a plurality of hydraulic cylinders, and the plurality of hydraulic cylinders are arranged at intervals between two different climbing devices.

Images