A hoist follow-up control hydraulic system

Abstract

This invention discloses a winch follow-up control hydraulic system, including a telescopic linkage and a winch linkage. When the boom is extended by operating the multi-way directional valve, the oil from port 1a of the telescopic linkage reaches port 1c of the boom telescopic one-way balance valve, and enters the rodless chamber of the boom telescopic cylinder through the boom telescopic one-way balance valve. The control oil flowing out of port 1c of the boom telescopic one-way balance valve is used to connect the motor working ports 2h and 2i of the winch motor through the winch follow-up control valve. Furthermore, the oil from port 1c of the boom telescopic one-way balance valve flows to the brake port of the winch motor through ports 2q and 2p of the winch follow-up control valve, putting the motor brake of the winch motor in the open state, so that the winch mechanism follows the boom as it extends. This invention enables the winch of a fire truck crane to descend along with the boom extension when the boom is extended.

Description

Technical Field

[0001] This invention belongs to the field of hydraulics and relates to hoisting technology, specifically to a hoist follow-up control hydraulic system. Background Technology

[0002] Truck-mounted cranes, fire and rescue cranes, and other lifting machinery are widely used in ports, power plants, fire and rescue operations, and other similar facilities. Under certain operating conditions, the crane's boom and winch must work in coordination to meet the demands of the work site and complete tasks quickly. Currently, truck-mounted cranes and fire and rescue cranes typically lack the function of having the winch lower as the boom extends. In actual operation, the common method is to observe the position of the hook while the boom is extended and then manually lower the winch to complete the extension. This method is not only laborious and time-consuming, but also delays the operation and makes precise control of the winch difficult.

[0003] Patent CN 211769958 U discloses a winch follow-up control hydraulic system. This system connects two electro-hydraulic proportional directional valves and a first electromagnetic directional valve in series between the two oil ports of the winch motor, forming a circuit that allows the winch motor to be in a free state. During hoisting operations, manual operation of the load's descent is unnecessary; the winch mechanism and the load can be lowered automatically. However, this patent uses a large number of electromagnetic and electro-hydraulic directional valves, and lacks damping in the oil circuit that keeps the motor in a floating state. These factors will cause instability in the winch's follow-up operation.

[0004] Patent CN 204454311 U discloses a rotary drilling rig and its winch follow-up control device. This design involves the wire rope being pulled out as the distance between the mast and the chassis increases during the mast erection process, with the winch using a floating rope delivery method. The design connects a large-diameter floating solenoid valve between the two working oil ports of the winch motor. During mast erection, this floating solenoid valve connects the two oil ports of the winch motor, enabling follow-up control of the mast and winch. However, the overall structure and operation of this patent are complex. Furthermore, the overflow valve between the working oil circuits of the winch motor has a pressure adjustment deviation, and the control valve between the motor's working pressure test ports has a reversing dead zone, which can cause instability in the winch's follow-up operation. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a winch follow-up control hydraulic system. In this solution, on the winch mechanism of a fire truck crane, through a winch follow-up control valve, the winch of the fire truck crane can follow the extension of the boom and descend, without the need for manual observation of the hook position and separate operation of the winch to lower the hook.

[0006] Technical solution: The present invention provides a winch follow-up control hydraulic system, including a multi-way directional valve telescopic link and a winch link, wherein the telescopic link includes a boom telescopic one-way balance valve and a boom telescopic cylinder, and the winch link includes a winch follow-up control valve and a winch motor.

[0007] The 1a oil port of the telescopic coupling is connected to the 1c oil port of the boom telescopic one-way balance valve. The 1c oil port of the boom telescopic one-way balance valve is connected to the rodless chamber of the boom telescopic cylinder through the boom telescopic one-way balance valve. The 1c oil port is also connected to the 2r oil port of the winch follow-up control valve.

[0008] When the multi-way directional valve is operated to extend the boom, the oil coming out from port 1a of the telescopic coupling reaches port 1c of the boom telescopic one-way balance valve, and enters the rodless chamber of the boom telescopic cylinder through the boom telescopic one-way balance valve.

[0009] The control oil flowing out of port 1c of the boom extension one-way balance valve is used to connect the motor working oil ports 2h and 2i of the winch motor through the winch follow-up control valve; and the oil from port 1c of the boom extension one-way balance valve flows to the brake oil port of the winch motor through ports 2q and 2p of the winch follow-up control valve, so that the motor brake of the winch motor is in the open state, so that the winch mechanism follows and descends while the boom extends.

[0010] Furthermore, the winch follow-up control valve includes a hydraulic check valve, the oil port of the winch follow-up control valve 2d is connected to the oil port of the winch follow-up control valve 2e through the hydraulic check valve, and the oil port of the winch link 2a is connected to the oil port of the winch follow-up control valve 2d through the oil port of the winch follow-up control valve 2c.

[0011] Furthermore, the hoist follow-up control valve includes a first electromagnetic directional valve, a check valve, and a damping orifice connected in parallel between the 2f port and the 2k port of the hoist follow-up control valve.

[0012] The 2f oil port of the hoist follower control valve is connected to the motor working oil port 2h of the hoist motor via the 2g oil port, and the 2k oil port of the hoist follower control valve is connected to the motor working oil port 2i of the hoist motor via the 2j oil port.

[0013] Furthermore, the winch follower control valve includes a one-way balance valve, which is connected between the 2l oil port and the 2k oil port of the winch follower control valve.

[0014] The 2l oil port of the winch follower control valve is connected to the 2b oil port of the winch assembly via the 2m oil port and the 2r oil port. A damping orifice and a hydraulic check valve are connected between the 2l oil port and the 2e oil port of the winch follower control valve.

[0015] Furthermore, the control oil flowing out of port 1c of the boom telescopic one-way balance valve reaches port 2r of the winch follower control valve, and after passing through port 2m of the winch follower control valve to port 2l, it splits into two paths. One path passes through the one-way balance valve and reaches port 2k of the winch follower control valve, and finally flows into the motor working port 2i of the winch motor. The other path passes through the damping orifice and the hydraulic control one-way valve, and finally flows into the motor working port 2h of the winch motor, thereby connecting the motor working port 2h and the motor working port 2i of the winch motor.

[0016] Furthermore, the high-pressure oil flows out from port 2b of the winch assembly, flows to port 2l of the winch follower control valve, passes through the one-way balance valve and reaches port 2k of the winch follower control valve, and finally flows into port 2i of the winch motor.

[0017] The oil flowing out from port 2l of the hoist follow-up control valve passes through the damping orifice, opens the hydraulic check valve, and flows into the motor working port 2i of the hoist motor. It then flows out from port 2h of the motor working port, reaches port 2f of the hoist follow-up control valve, passes through the previously opened hydraulic check valve, and flows back to the oil tank through ports 2d and 2c of the hoist follow-up control valve and port 2a of the hoist connection, thus completing the hoist descent.

[0018] Furthermore, the hoist follow-up control valve includes a first shuttle valve and a second shuttle valve. The first shuttle valve is connected between the 2c oil port and the 2m oil port of the hoist follow-up control valve. The output oil of the first shuttle valve reaches the hoist brake of the hoist motor through the second shuttle valve, the 2n oil port, the 2q oil port, and the 2p oil port of the hoist follow-up control valve.

[0019] Furthermore, the hoist follow-up control valve also includes a second electromagnetic directional valve, which is connected between the oil port 2q of the hoist follow-up control valve and the second shuttle valve; the oil port 2q of the hoist follow-up control valve is connected to the oil port 2r.

[0020] Furthermore, when the second electromagnetic reversing valve is energized, the control oil from the boom telescopic one-way balance valve 1c reaches the winch follower control valve 2q, and then passes through the second electromagnetic reversing valve, the second shuttle valve (24), the winch follower control valve 2n, and the winch follower control valve 2p to the winch motor brake port, thereby opening the winch motor brake.

[0021] Furthermore, the 1a oil port of the telescopic coupling is connected to the 1d oil port of the boom telescopic one-way balance valve, and the 1d oil port of the boom telescopic one-way balance valve is connected to the rodless chamber of the boom telescopic cylinder through the internal oil circuit of the boom telescopic one-way balance valve.

[0022] The rod chamber of the boom telescopic cylinder is connected to the oil port 1f of the boom telescopic one-way balance valve, the oil port 1f of the boom telescopic one-way balance valve is connected to the oil port 1g of the boom telescopic one-way balance valve, and the oil port 1g is connected to the oil port 1b of the telescopic coupling.

[0023] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] (1) When the crane boom needs to be extended quickly for operation, the boom can work in coordination with the winch mechanism through the winch follow-up control valve. This means that when the boom is extended, there is no need to operate the winch mechanism separately multiple times to lower it to an appropriate distance according to the operation requirements before the boom is extended. Through the winch follow-up control valve, the boom and the winch work together to optimize the crane's operation control mode, improve the operation speed, and save operation time.

[0025] (2) By using the winch follow-up control valve, during long-term and multiple operations of the boom, there is no need to simply operate the winch mechanism, which is conducive to improving the efficiency of the whole system and saving energy. Attached Figure Description

[0026] Figure 1 This is a hydraulic schematic diagram of the winch follow-up control hydraulic system described in this invention. Detailed Implementation

[0027] The technical solution of the present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0028] like Figure 1 As shown, the components involved in the winch follow-up control hydraulic system of the present invention are as follows: boom telescopic one-way balance valve 11, boom telescopic cylinder 12, winch follow-up control valve 21, winch motor 22, first shuttle valve 23, second shuttle valve 24, hydraulic control one-way valve 25, winch follow-up control valve one-way valve 26, first electromagnetic directional valve 27, second electromagnetic directional valve 28, one-way balance valve 29, telescopic connection oil ports 1a-1b, boom telescopic balance valve oil ports 1c-1g, winch connection oil ports 2a-2b, motor working oil ports 2h-2i, and winch follow-up control valve oil ports 2c, 2d, 2e, 2f, 2g, 2j, 2k, 2l, 2m, 2n, 2o, 2p, 2q, 2s.

[0029] The winch follow-up control hydraulic system of the present invention includes a multi-way directional valve, which includes a telescopic link and a winch link. The telescopic link includes a boom telescopic one-way balance valve 11 and a boom telescopic cylinder 12. The winch link includes a winch follow-up control valve 21 and a winch motor 22. The winch follow-up control valve 21 includes a first shuttle valve 23, a second shuttle valve 24, a hydraulically controlled one-way valve 25, a winch follow-up control valve one-way valve 26, a first solenoid directional valve 27, a second solenoid directional valve 28, and a one-way balance valve 29.

[0030] The extension port 1a of the multi-way directional valve is connected to port 1c of the boom extension one-way balance valve 11. Port 1c of the boom extension one-way balance valve 11 is connected to port 1d of the boom extension one-way balance valve 11. Port 1d of the boom extension one-way balance valve is connected to the rodless chamber of the boom extension cylinder 12 via the internal oil passage of the balance valve. The rod chamber of the boom extension cylinder 12 is connected to port 1f of the boom extension one-way balance valve 11. Port 1f of the boom extension one-way balance valve 11 is connected to port 1g. Port 1g is connected to port 1b of the extension port of the multi-way directional valve.

[0031] The principle of boom extension in this invention is as follows: By operating the multi-way directional valve, high-pressure oil flows out from port 1a of the telescopic coupling, passes through port 1c of the boom telescopic one-way balance valve 11, and reaches port 1d of the same valve. After opening the valve, the high-pressure oil flows to port 1e and finally into the rodless chamber of the boom telescopic cylinder 12. Oil flows out from the rod chamber of the cylinder 12 to port 1f, passes through the boom telescopic one-way balance valve 11, flows to port 1g, and finally returns to the oil tank via the multi-way directional valve.

[0032] The boom retraction principle is as follows: Operating the multi-way directional valve, high-pressure oil flows out from port 1b of the telescopic linkage, reaching port 1g of the boom telescopic one-way balance valve 11. The high-pressure oil then passes through the pilot control circuit, opens the boom telescopic one-way balance valve 11, and flows to port 1f, ultimately flowing into the rod chamber of the boom telescopic cylinder 12. Oil flows out from the rodless chamber of the boom telescopic cylinder 12, reaching port 1e. After passing through the boom telescopic one-way balance valve 11, it flows to port 1d, and finally returns to the oil tank through port 1a of the multi-way directional valve.

[0033] The 2a oil port of the multi-way directional valve is connected to the 2c oil port of the hoist follower control valve 21. The 2c oil port and the 2m oil port of the hoist follower control valve 21 are connected to a first shuttle valve 23. The output oil of the first shuttle valve 23 passes through a second shuttle valve 24, and then through the 2n, 2q, and 2p oil ports of the hoist follower control valve 21 to the hoist brake of the hoist motor 22. The 2c oil port and the 2d oil port of the hoist follower control valve 21 are connected, and the 2d oil port and the 2e oil port of the hoist follower control valve 21 are connected via a hydraulic check valve 25. The 2f oil port and the 2k oil port of the hoist follower control valve 21 are connected in parallel with a first solenoid directional valve 27, a check valve, and a damping orifice. The 2f port of the winch follower control valve 21 is connected to the 2h port of the winch motor 22 via the 2g port. The 2k port of the winch follower control valve 21 is connected to the motor working port 2i of the winch motor 22 via the 2j port. The winch connection port 2b of the multi-way directional valve is connected to the 2l port of the winch follower control valve 21. The one-way balance valve 29 is connected between the 2l port and the 2k port of the winch follower control valve 21. A damping orifice and a hydraulically controlled one-way valve 25 are connected between the 2l port and the 2e port of the winch follower control valve 21. The output oil path of the first shuttle valve 23 includes the second shuttle valve 24 and the second solenoid directional valve 28. The output oil path of the first shuttle valve 23 flows through the second shuttle valve 24 to the second oil port of the second shuttle valve 24 (i.e., the left oil port of the second solenoid directional valve 28). The output oil path of the second shuttle valve 24 flows through the 2n oil port, the 2q oil port, and the 2p oil port to the winch brake of the winch motor 22. The second solenoid directional valve 28 is connected between the oil port 2q of the winch follower control valve 21 and the second shuttle valve 24. The oil port 2q of the winch follower control valve 21 is connected to the oil port 1a of the telescopic coupling via the 2r oil port.

[0034] The working principle of the hoisting mechanism of this invention is as follows: the first electromagnetic reversing valve 27 is de-energized and operates in the lower position, the second electromagnetic reversing valve 28 is de-energized and operates in the upper position, controlling the multi-way reversing valve, high-pressure oil flows out from the hoisting port 2a of the multi-way valve and flows to the 2d port of the hoisting follow-up control valve 21, and at the same time reaches the first shuttle valve 23 through the 2c port. The output oil of the first shuttle valve 23 flows to the second shuttle valve 24. The output oil of the second shuttle valve 24 reaches the hoisting brake through the 2n port, the 2q port, and the 2p port, opening the hoisting brake. The high-pressure oil flowing to port 2d of the hoist follow-up control valve 21 passes through the hydraulic check valve 25 and reaches port 2e. Due to the check valve function on the left side of the hydraulic check valve 25 and the first solenoid directional valve 27, the oil is stopped before the check valve on the left side of the hydraulic check valve 25 and the first solenoid directional valve 27, and flows into the motor working port 2h of the hoist motor 22 after passing through port 2g. The oil flowing into the motor working port 2h of the hoist motor 22 flows out through the internal oil circuit of the motor and exits through the motor working port 2i, flowing to port 2k. At this time, as mentioned above, the oil in the 2a oil circuit opens the one-way balance valve 29 through port 2d, connecting port 2k with ports 2l, 2m, and 2b. Therefore, the oil flowing out of the motor working port 2i finally flows back to the oil tank through the multi-way valve, thus completing the hoisting lifting function.

[0035] The working principle of the hoist descent of this invention is as follows: The first electromagnetic reversing valve 27 is de-energized and operates in the lower position; the second electromagnetic reversing valve 28 is de-energized and operates in the upper position. This controls the multi-way reversing valve, causing high-pressure oil to flow out from the hoisting port 2b of the multi-way valve and to the 2m port of the hoisting follow-up control valve 21. Simultaneously, after passing through the output port of the first shuttle valve 23, it flows to the second shuttle valve 24. The output oil from the second shuttle valve 24 then passes through ports 2n, 2q, and 2p to reach the hoisting brake of the hoisting motor 22, opening the hoisting brake. Simultaneously, the oil at port 2l passes through the one-way balance valve 29 and reaches port 2k, finally flowing into the motor working port 2i. The oil flowing out from port 2l passes through the damping orifice, opening the hydraulic control check valve 25 between ports 2e and 2d. The oil flows through the internal oil circuit of the motor, exiting from the motor working port 2h and reaching the 2f port of the winch follower control valve 21. Due to the one-way function of the one-way valve 26 of the winch follower control valve, the oil is blocked at the 2e port. Therefore, the oil flowing out from the motor working port 2h passes through the hydraulic control one-way valve 25 between the previously opened 2e port and 2d port, and then flows back to the oil tank through the multi-way valve via the 2d port, 2c port, and 2a port, thus completing the winch lowering function.

[0036] When the follow-up function of the winch mechanism needs to be activated, that is, when the winch follows the boom as it extends, the first solenoid directional valve 27 and the second solenoid directional valve 28 are energized, and the first solenoid directional valve 27 and the second solenoid directional valve 28 operate in the upper and lower positions, respectively. At this time, the 2k oil port of the winch follow-up control valve 21 is connected to the 2f oil port through the first solenoid directional valve 27, and the 2q oil port is connected to the output oil port 2n of the second shuttle valve 24 through the second solenoid directional valve 28, and finally connected to the brake oil port through the 2q oil port and the 2p oil port. When the multi-way valve is operated to extend the boom, the oil in the telescopic coupling 1a oil port enters the rodless chamber of the boom telescopic cylinder 12, flows from the rod chamber of the boom telescopic cylinder 12 through the boom telescopic one-way balance valve 11 to the telescopic coupling 1b oil port of the multi-way valve, and finally flows to the oil tank. Simultaneously, the control oil from port 1a of the telescopic linkage reaches port 2r via port 1c of the boom telescopic one-way balance valve 11. The oil flowing from port 2r into port 2l is divided into two paths: one path flows through the damping orifice, the hydraulic control one-way valve 25, and ports 2e, 2f, and 2g of the winch follow-up control valve 21 to the motor working port 2h; the other path flows through the one-way balance valve 29, ports 2k and 2j to the motor working port 2i. Therefore, the control oil flowing out of port 1c connects the motor working ports 2h and 2i. Furthermore, the oil from port 1c reaches port 2q via port 2r, and then reaches the second solenoid directional valve 28. The second solenoid directional valve 28 is in the lower position, and the oil flows through the second shuttle valve 24, ports 2q and 2p to the brake port of the winch motor 22, thus putting the motor brake in the open state. Ultimately, when the boom extends, the two working oil ports of the motor are connected and the motor brake is opened, achieving the function of the winch mechanism following the boom's descent while it extends, thus completing the follow-up control of extension and winch.

Claims

1. A hoist follow-up control hydraulic system characterized by: It includes a multi-way directional valve telescopic link and a winch link. The telescopic link includes a boom telescopic one-way balance valve (11) and a boom telescopic cylinder (12). The winch link includes a winch follow-up control valve (21) and a winch motor (22). The 1a oil port of the telescopic coupling is connected to the 1c oil port of the boom telescopic one-way balance valve (11). The 1c oil port of the boom telescopic one-way balance valve (11) is connected to the rodless chamber of the boom telescopic cylinder (12) through the boom telescopic one-way balance valve (11). The 1c oil port is also connected to the 2r oil port of the winch follow-up control valve (21). When the boom is extended by manipulating the multi-way directional valve, the oil coming out from port 1a of the telescopic coupling reaches port 1c of the boom telescopic one-way balance valve (11), and enters the rodless chamber of the boom telescopic cylinder (12) through the boom telescopic one-way balance valve (11). The control oil flowing out of port 1c of the boom extension one-way balance valve (11) is used to connect the motor working port 2h and the motor working port 2i of the winch motor (22) through the winch follow-up control valve (21); and the oil from port 1c of the boom extension one-way balance valve (11) flows to the brake port of the winch motor (22) through ports 2q and 2p of the winch follow-up control valve (21), so that the motor brake of the winch motor (22) is in the open state, so that the winch mechanism follows and descends at the same time as the boom extends. The winch follow-up control valve (21) includes a hydraulic check valve (25). The 2d oil port of the winch follow-up control valve (21) is connected to the 2e oil port of the winch follow-up control valve (21) through the hydraulic check valve (25). The 2a oil port of the winch link is connected to the 2d oil port of the winch follow-up control valve (21) through the 2c oil port of the winch follow-up control valve (21). The winch follower control valve (21) includes a first electromagnetic reversing valve (27), a check valve and a damping orifice connected in parallel between the 2f oil port and the 2k oil port of the winch follower control valve (21); The 2f oil port of the hoist follower control valve (21) is connected to the motor working oil port 2h of the hoist motor (22) via the 2g oil port, and the 2k oil port of the hoist follower control valve (21) is connected to the motor working oil port 2i of the hoist motor (22) via the 2j oil port. The winch follower control valve (21) includes a one-way balance valve (29), which is connected between port 21 and port 2k of the winch follower control valve (21). The 2l port of the winch follower control valve (21) is connected to the 2b port of the winch assembly via the 2m port and the 2r port. A damping orifice and a hydraulic check valve (25) are connected between the 2l port and the 2e port of the winch follower control valve (21).

2. The hoist follow-up control hydraulic system of claim 1, wherein: The control oil flowing out of port 1c of the boom telescopic one-way balance valve (11) reaches port 2r of the winch follower control valve (21). After passing through port 2m of the winch follower control valve (21) to port 2l, it is divided into two paths. One path passes through the one-way balance valve (29) and reaches port 2k of the winch follower control valve (21), and finally flows into the motor working port 2i of the winch motor (22). The other path passes through the damping orifice and the hydraulic control one-way valve (25), and finally flows into the motor working port 2h of the winch motor (22), thereby connecting the motor working port 2h and the motor working port 2i of the winch motor (22).

3. The hoist follow-up control hydraulic system of claim 1, wherein: High-pressure oil flows out from port 2b of the winch assembly, flows to port 2l of the winch follower control valve (21), passes through the one-way balance valve (29) and reaches port 2k of the winch follower control valve (21), and finally flows into port 2i of the winch motor (22). The oil flowing out from port 2l of the hoist follower control valve (21) passes through the damping orifice and opens the hydraulic control check valve (25), flowing into the motor working port 2i of the hoist motor (22). The oil flows out from port 2h and reaches port 2f of the hoist follower control valve (21). After passing through the previously opened hydraulic control check valve (25), it flows back to the oil tank through ports 2d, 2c, and 2a of the hoist follower control valve (21), thus completing the hoist descent.

4. The hoist follow-up control hydraulic system of claim 1, wherein: The hoist follow-up control valve (21) includes a first shuttle valve (23) and a second shuttle valve (24). The first shuttle valve (23) is connected between the 2c oil port and the 2m oil port of the hoist follow-up control valve (21). The output oil of the first shuttle valve (23) reaches the hoist brake of the hoist motor (22) through the second shuttle valve (24), the 2n oil port, the 2q oil port and the 2p oil port of the hoist follow-up control valve (21).

5. The hoist follow-up control hydraulic system of claim 4, wherein: The winch follower control valve (21) also includes a second electromagnetic reversing valve (28), which is connected between the oil port 2q of the winch follower control valve (21) and the second shuttle valve (24); the oil port 2q of the winch follower control valve (21) is connected to the oil port 2r.

6. The hoist follow-up control hydraulic system of claim 5, wherein: When the second electromagnetic reversing valve (28) is energized, the control oil from the 1c port of the boom telescopic one-way balance valve (11) reaches the 2q port of the winch follower control valve (21), and then passes through the second electromagnetic reversing valve (28), the second shuttle valve (24), the 2n port of the winch follower control valve (21), and the 2p port of the winch follower control valve (21) to reach the brake port of the winch motor (22), thereby opening the motor brake of the winch motor (22).

7. The winch follow-up control hydraulic system according to claim 6, characterized in that: The 1a oil port of the telescopic coupling is connected to the 1d oil port of the boom telescopic one-way balance valve (11), and the 1d oil port of the boom telescopic one-way balance valve (11) is connected to the rodless chamber of the boom telescopic cylinder (12) through the internal oil circuit of the boom telescopic one-way balance valve (11). The boom telescopic cylinder (12) has a rod chamber that is connected to the 1f port of the boom telescopic one-way balance valve (11), the 1f port of the boom telescopic one-way balance valve (11) is connected to the 1g port of the boom telescopic one-way balance valve (11), and the 1g port is connected to the 1b port of the telescopic coupling.

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