JPH0589361U - Rotating support device for cable drum - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the cables from drooping greatly from utility poles, etc. when the cables are being drawn out, and to enable safe crossover work. [Configuration] Brake roller 5 on which the cable drum D is placed
Is allowed to move in a tangential direction while being in contact with the cable drum D, the valve of the brake valve 12 is opened in conjunction with this movement, and the hydraulic motor 10 for rotating the brake roller 5 is operable. [Effect] The cable does not hang down between the electric poles during the crossing work, and the cable drum can be stopped without requiring manual work, and the work can be performed safely.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cable drum brake structure in which a drum around which a cable is wound is automatically stopped at the time of crossing over a transmission line or the like.

[0002]

[Prior Art]

 For the work of crossing cables such as power lines to steel towers and poles, it is common to prepare a coil with the cable wound and unwind the cable from this drum. FIG. 16 is a schematic view showing an example of such an interrogation work, in which a cable 51 is sequentially disposed over three electric poles 50a, 50b, 50c. The cable 51 is wound around a drum 52 mounted on a truck or the like, and is wound out in order, bridged over utility poles 50a to 50c, connected to an intermediary drum 53 mounted on another truck, and pulled. By such an operation, the drum 52 pays out the cable 51, while the intermediary drum 53 pulls the cable 51 and bridges the cable 51 between the electric poles 50a to 50c so as to obtain an appropriate tension.

The drum 52 has a hole formed in the center thereof, and a bracket or the like provided on the track is inserted into the hole and is supported so as to freely rotate. The same applies to the intermediary drum 53, and there are those for winding the cable 51 manually or by using a dedicated motor or the like.

[0004]

[Problems to be solved by the device]

 In the work of straddling the cable 51, if the rotations of the drum 52 and the straddle drum 53 are properly coordinated, the cable 51 will not hang down during the work as shown by the chain line in the figure. However, conventionally, the rotation speeds of the drum 52 and the intermediary drum 53 could only be adjusted by the operator in charge of each. One of the reasons for this is that the drum 52 is simply set on a bracket or the like so that it can rotate freely, and it does not have a mechanism for adjusting the rotation of the drum 52.

In actual work, the distance between the drum 52 side and the intermediation drum 53 side may be greatly separated, so that the worker on the intermediary drum 53 side sends the cable 52 to the drum 52 on the side to which it is fed. It is not possible to contact the worker who is doing it immediately. Moreover, the drum 52 around which the cable 51 is wound has a large total weight, and even if the drum 52 is stopped while it is rotating, it takes time to stop due to its inertia. For this reason, it takes some time before the drum 52 is stopped after the workers communicate with each other, and it takes time to stop the rotation due to the inertia. I will end up. As a result, as shown by the alternate long and short dash line in the figure, the cable 51 drastically hangs down between the electric poles 50a to 50c, and the building 51 on the ground or the crops in the fields are damaged.

In order to prevent such an accident, the drum 52 should be stopped as quickly as possible, but if the communication between the workers is delayed a little, the same problem as described above occurs. Further, the means for stopping the drum 52 is nothing but means, for example, that a burl is abutted against the outer peripheral surface of the drum 52 by a leverage action and the friction is utilized to stop the rotation. For this reason, it is not possible to stop the drum 52 quickly, it is not possible to prevent the cable 51 from hanging down, and the danger to the operator is very high.

The problem to be solved in the present invention is to prevent a cable from drooping greatly from a utility pole or the like when the cable is paid out, and to enable a safe crossover work.

[0008]

[Means for Solving the Problems]

 According to the present invention, an arm that rotatably supports a shaft of a cable drum and can move its support point up and down, a brake roller that covers the cable drum from above and receives its peripheral surface, and the brake roller The brake roller is provided with means for urging in the direction of the contact portion with the cable drum, a hydraulic motor for driving the brake roller so as to rotate in the forward and reverse directions, and a brake valve provided in a hydraulic circuit to the hydraulic motor. The rotor can move in the tangential direction of the cable drum while maintaining contact with the peripheral surface due to the friction received when the cable drum rotates, and the brake valve projects the plunger that opens the built-in valve mechanism to the outside. At the same time, the movement of the brake roller is mechanically connected to the plunger, and when the plunger is pushed, the valve mechanism can be opened. Characterized in that was.

[0009]

[Action]

 The cable drum around which the cable is wound is supported by an arm and its peripheral surface is abutted against the peripheral surface of the break drum. At this time, when the cable of the cable drum is unwound, the cable drum rotates and at the same time exerts a frictional force between the cable drum and the brake drum. This frictional force acts in the direction that pushes the brake drum if it does not rotate, and the brake drum moves in the tangential direction that is the same direction as the rotation direction of the cable drum. This pushes the plunger of the brake valve to open the hydraulic circuit, and the hydraulic motor causes the brake roller to start rotating. Therefore, when the rotation of the cable drum slows or stops, the frictional force on the cable drum also decreases, and the brake drum returns to the initial position by the biasing means. Therefore, since the force pushing the plunger is also eliminated, the internal flow path of the brake valve is closed and the hydraulic motor is stopped, and at the same time, the brake roller is also stopped to brake the cable drum.

[0010]

【Example】

 FIG. 1 is a side view of a cable feeding device having a brake mechanism of the present invention, and FIG. 2 is a front view thereof.

In the figure, a cable feeding device has a base 1 fixed to a truck for crossing work as a base, and a pair of arms 2 for rotatably supporting a cable drum D on the base 1 are vertically rotated. It is installed freely. These arms 2 are connected to a rod 3a of a hydraulic cylinder 3 whose base end is pivotally attached to the base 1 and can be moved up and down as shown by the solid line and the alternate long and short dash line in FIG. A support block 4 is provided on the upper end of the arm 2 to rotatably support the shaft E of the cable drum D. The support block 4 is fixed by using a plurality of mounting holes 2a formed in the arm 2 and inserting a pin 2b into the mounting hole 2a. For example, the position can be changed from the position shown by the solid line in FIG. You can A guide portion 4a is provided on the upper surface of the support block 4 so that the shaft E of the cable drum can be easily placed thereon, and a holding portion 4b into which the shaft E falls is formed at the lower end thereof. Then, the lock lever 4c is provided so that the shaft E in which the holding portion 4b is housed does not bounce or come out.

The base 1 is provided with a brake roller 5 that receives the circumferential surface of the cable drum D when it rotates and brakes the cable drum D when necessary. 4 and 5 are a schematic side view and a schematic plan view showing the arrangement of the brake roller 5, respectively.

FIG. 6 is a cutaway side view showing an installation structure of the brake roller 5 on the base 1, and FIG. 7 is a vertical cross-sectional view taken along a plane including the axis of the brake roller 5.

A pair of brackets 1 a is fixed to the inside of a cylinder 2 arranged at both left and right ends of the base 1 in the width direction, and an outer case 6 and an inner case 7 for supporting a brake roller 5 are fixed therein. I have paid. The outer case 6 has a box shape with a part of the bottom surface opened, is slidably incorporated in the inner wall of the bracket 1a, and is movable left and right in FIG. In order to guide this movement, the bracket 1a is provided with a guide hole 1b, and the outer case 6 is provided with a slide block 6a which fits in the guide hole 1b and slides. The inner case 7 is covered on the outer case 6 like a lid, and is incorporated so as to be vertically movable with respect to the outer case 6. For this movement, a guide hole 6b is formed in the outer case 6 in the vertical direction, and a slide block 7a which is slidable in the guide hole 6b is provided on the outer side of the inner case 7. Further, the inner case 7 incorporated in the outer case 6 so as to be movable up and down is supported by four coil springs 8. Therefore, when a load from above is applied to the inner lead 7, the coil spring 8 receives this and buffers it. With such a structure, the inner case 7 can be horizontally moved on the base 1, and at the same time, can be installed on the base 1 so as to be vertically displaceable.

As shown in FIG. 7, the cable roller 5 is incorporated in the inner case 7 so as to have a horizontal axis. The brake roller 5 is rotatably attached to blocks 9a and 9b fixed in an inner case 7 via bearings 9c, and is rotationally driven by a hydraulic motor 10 housed in one block 9a.

A rod 6 c is protruded from the front end side of the outer case 6 accommodating the brake roller 5, and the rod 6 c is passed through the receiving block 1 c fixed to the base 1. A coil spring 11 is incorporated between the receiving block 1c and the outer case 6 and biases the outer case 6 away from the receiving block 1c. Therefore, in a normal case, the biasing force of the coil spring 11 holds the slide block 6a of the outer case 6 at the position where it abuts against the right end of the guide hole 1b of the bracket 1a, as shown in FIG. Become.

Here, when the cable drum D wound with the cable C is placed on the brake roller 5, the core of the brake roller 5 and the core of the cable drum D are set to be slightly displaced in the horizontal direction. That is, as shown in FIG. 8, the core O of the brake roller 5 is shifted toward the receiving block 1c side from the core P of the cable drum D so that these cores O and P are not on a common vertical line.

Further, the base 1 is provided with a brake valve 12 that opens and closes the flow path of the hydraulic circuit by the movement of the outer case 6 that holds the brake roller 5. FIG. 9 is a vertical cross-sectional view of the brake valve 12, in which a spool 12d is housed in an internal passage between an inlet port 12b and an outlet port 12c provided in a main body 12a so as to be movable in the axial direction thereof. A plunger 12e that protrudes from the main body 12a and strikes the rod 6c of the outer case 6 is provided on the tip end side of the spool 12d. Further, a coil spring 12f for urging the spool 12d in the direction of the plunger 12e is provided on the proximal end side of the spool 12d. As shown in FIG. 10, the spool 12d has four grooves 12g axially formed on its outer peripheral surface in order to open and close the flow path between the inlet port 12b and the outlet port 12c.

In such a brake valve 12, in the state shown in FIG. 9, the valve body portion 12h of the spool 12d blocks the flow passage between the inlet port 12b and the outlet port 12c. Then, when the rod 12e moves to the left and pushes the spool 12d, the groove 12g of the valve body portion 12h gradually moves to the inlet port 12b side, and is connected to the inner peripheral wall of the internal flow path by the groove 12g. The passage will be opened. Therefore, the inlet port 12b to the outlet port 12c communicate with each other to open the hydraulic circuit. Therefore, when the outer case 6 is in the state shown in FIG. 6, the internal flow path of the brake valve 12 is closed, but the brake valve 12 operates the hydraulic circuit in conjunction with the movement of the outer case 6 to the left. become.

FIG. 11 is a hydraulic circuit diagram for driving the hydraulic motor 10 and the cylinder 3.

In the figure, in the hydraulic circuit from the hydraulic pump 20 and the tank 21 to the cylinder 3, a cylinder switching valve 22 and a pressure adjusting valve 23 are incorporated, and two ports 24 a, 24 b and 24 c are used to provide two ports. An oil passage is connected to the cylinder 3. In addition, 24 is a pressure gauge. Further, two hydraulic motor switching valves 25 and 26 are provided in the hydraulic circuit from the hydraulic pump 20 and the tank 21 to the hydraulic motor 10, and the circuits to the hydraulic motor 10 are connected by the ports 28a and 28b. There is. A hydraulic circuit to the brake valve 12 is connected to the hydraulic motor switching valve 26 through ports 29a and 29b.

The operation of the cylinder 3 and the brake valve 12 by this hydraulic circuit is as follows. From the mounting of the cable drum D to the support block 4 and the pressing of the brake roller 5 to the feeding and winding of the cable C. Will be described.

First, the axis E of the cable drum D is placed on the support block 4 of the arm 2 as shown in FIGS. 2 and 3. After that, the rod 3a is contracted by the supply of pressure oil to the cylinder 3, and the arm 2 is tilted to the brake roller 5 side. By this operation, the outer peripheral surface of the cable drum D comes to rest on the peripheral surface of the brake roller 5 as shown in FIG. The cable drum D has a standard outer diameter, and several types are used. By changing the height of the support point by tilting the arm 2, the outer surface of the cable drum D can be properly moved to the brake roller 5. Can be placed on top of.

Such operation of the cylinder 3 is performed by the hydraulic circuit of FIG. 11, and when the cable drum D is placed on the brake roller 5, the cylinder switching valve 22 is switched to the port A position. By this operation, the port a is connected to the port 24a of the cylinder 3, and the port b is also connected to the port 24b of the cylinder 3. Therefore, the pressure oil of the hydraulic pump 20 enters the cylinder 3 via the port a and the port 24a, and the pressure oil in the cylinder 3 returns to the tank 21 through the ports 24b and b. Therefore, the rod 3a of the cylinder 3 is lowered, the posture of the arm 2 is changed so that the arm 2 is also inclined downward, and the cable drum D can be placed on the brake roller 5.

When the cylinder switching valve 22 is switched to the port B as shown in FIG. 12 with the cable drum D placed on the support block 4, the pressure oil of the hydraulic pump 20 passes through the port b to the cylinder 3 Port 24b of the above and pushes up the rod 3a to raise the arm 2. By this operation, the shaft E of the cable drum D is automatically fitted into the holding portion 4b of the support block 4, and the shaft E is held by manually closing the lock lever 4b. At this time, the internal pressure oil of the cylinder 3 returns to the tank 21 from the port b of the cylinder switching valve 22 through the port 24a.

By operating the cylinder switching valve 22 as described above, the outer peripheral surface of the cable drum D is placed on the brake roller 5, and at the same time, the shaft E of the cable drum D is rotatably supported by the support block 4. it can.

Here, the cable drum D supported by the support block 4 needs to be set in a pressed state on the brake roller 5 so as not to slip with the peripheral surface of the brake roller 5. Therefore, the pressure of the cylinder 3 is adjusted by the pressure adjusting valve 23. This operation may be performed by setting the cylinder switching valve 22 shown in FIG. 13 to the position where the port A is switched and adjusting the rolling force by the rod 3a. This operation is the same as when setting the cable drum D shown in FIG.

Further, when the cable drum D does not need to be braked by the brake roller 5 such as the feeding or winding of the cable C, as shown in FIG. 14, the hydraulic motor switching valve 26 is connected to the port. After switching to the B position, the other hydraulic motor switching valve 25 is arbitrarily switched to port A or port B. As a result, the hydraulic motor 10 rotates to rotate the brake roller 5. The rotating direction of the brake roller 5 can be set to either the feeding direction or the winding direction of the cable C 1 by the switching operation of the hydraulic motor switching valves 25 and 26. Therefore, in FIG. 1, when the brake roller 5 is rotated counterclockwise, the cable drum D rotates in the direction in which the cable C is paid out, and when the brake roller 5 rotates clockwise, the cable C is wound up. The cable drum D rotates in the direction.

Further, when the cable C is fed from the cable drum D while applying a constant tension to the cable C, first, the cable drum D is set so as to be mounted on the brake roller 5 with an appropriate pressure contact force. This operation is performed by handling the cylinder switching valve 22 shown in FIG. After the adjustment of the pressure contact force of the cable drum D to the brake roller 5 is completed, as shown in FIG. 15, it is confirmed that the hydraulic motor switching valve 25 is in the neutral position, and then the other hydraulic motor switching valve 25. Switch 26 to port A. As a result, the circuit of the hydraulic motor 10 is connected from the port 28a to the port 29b on the inlet side of the brake valve 12 and then the port 29a on the outlet side to the port a of the hydraulic motor switching valve 26. The ports a and b are connected by the neutral position of the valve 25 to reach the port 28a side of the hydraulic motor 10 again to form a circulation circuit. With this circuit, when the hydraulic motor 10 tries to rotate counterclockwise as shown in the figure, it does not rotate unless the brake valve 12 is opened. Therefore, the rotation of the hydraulic motor 10 can be freely controlled by appropriately opening and closing the brake valve 12 by an external force. Therefore, the rotation of the brake roller 5 connected to the hydraulic motor 10 is controlled, and the rotation of the cable drum D pressed against the brake roller 5 is also resisted. It is possible to give.

In the above-described configuration, after the cable drum D is supported by the support block 4 and the peripheral surface thereof is placed on the brake roller 5, the cable C is paid out by the hydraulic motor switching valve 25, as described in FIG. By operating 26, the break roller 5 is rotated counterclockwise in FIG. The rotation of the brake roller 5 causes the cable drum D, which is in pressure contact with the peripheral surface thereof, to rotate clockwise, and the cable C can be fed out by pulling the tip of the cable C as shown in FIG. ..

On the other hand, the brake roller 5 can be used not only for rotating the cable drum D in the feeding direction of the cable C but also for winding it up, and can be used as a substitute for the intermediary drum 53 shown in FIG. 16 of the conventional example. ..

In this case, the cable drum D is left empty and the tip of the cable C spanning this is connected. Then, as shown in FIG. 4, the outer peripheral surface of the cable drum D is strongly pressed onto the brake drum 5 using the cylinder 3. Then, when the hydraulic motor switching valve 26 is switched to the b port position in FIG. 14, the hydraulic circuit of the hydraulic motor 10 causes the hydraulic motor switching valve 25 to have the A port and the other hydraulic motor switching valve 26 b port. The flow is from port, port 28a to port 28b. Therefore, the brake roller 5 rotates clockwise in FIG. 1, and the cable drum D pressed against the brake roller 5 rotates counterclockwise to wind up the cable C. As described above, the cable C that has been crossed over or a cable that is newly prepared can be used to wind up the cable drum D.

Here, when the cable C is fed, the break roller 5 pressed against the cable drum D tries to rotate due to frictional resistance between the cable C and the rotating cable drum D. On the other hand, the pressure oil inside the hydraulic motor 10 connected to the brake roller 5 is discharged from the b port of the hydraulic motor 10, passes through the brake valve 12 via the ports 28b and 29b, and is switched from the port 29a to the hydraulic motor. It passes through the circuit of the port a of the valve 26, and is connected from the port A to the port B to try to circulate. However, the brake valve 12 is in the state of FIG. 6 when the cable drum D is placed on the brake roller 5 and started to rotate, and the spool 12d is in the position of FIG. For this reason, the internal flow path of the brake valve 12 remains closed, the pressure on the port b side of the hydraulic motor 10 rises, the hydraulic motor 10 does not rotate, and as a result, the brake roller 5 cannot rotate.

When the brake roller 5 cannot rotate in this way, the brake roller 5 is pushed to the left as indicated by the arrow in FIG. 8 by the frictional force between the brake roller 5 and the cable drum D. That is, since the outer case 6 which houses the brake roller 5 has the slide block 6a slidably fitted in the guide hole 1b of the bracket 1a, the force pushing the outer peripheral surface of the brake roller 5 to the left is coiled. The outer case 6 is moved against the spring 11. The level of the contact position between the cable drum D and the brake roller 5 gradually decreases due to the movement of the outer case 6, but since the coil spring 8 urges the inner case 7 upward, The break roller 5 always maintains a contact state.

The outer case 6 moves in the direction in which the rod 6c pushes the plunger 12e of the brake valve 12, so the spool 12d therein moves to the left in FIG. Therefore, the groove 12g of the valve body 12h allows the inlet port 12b and the outlet port 12c to communicate with each other to form a circulation circuit. The groove 12g of the spool 12d expands in accordance with the amount of movement of the outer case 6 so that the maximum flow rate of the pressure oil flows at the maximum stroke.

In this way, by utilizing the fact that the brake roller 5 does not rotate at first, the inner case of the brake valve 12 is opened by pushing the outer case 6 by the rotation when the cable C is paid out from the cable drum D. You can Therefore, when the cable drum D continues to rotate, the hydraulic motor 10 also rotates the brake roller 5 and does not give friction resistance to the cable drum D. Therefore, the cable drum D can freely rotate, and the cable C can be unwound easily.

In some cases, it may be necessary to stop the feeding of the cable C during the process of straddling the cable C, and the feeding of the cable C may be stopped. In this case, the pulling force on the cable C by the operator or the winch for the interference is reduced or becomes zero, so that the cable drum D gradually slows its rotation and eventually stops. In this case, if the time from when the cable C needs to be stopped to when the rotation of the cable drum D is stopped must be shortened, the cable C between the electric poles drastically drops as described in the section of the prior art. become.

On the other hand, when the rotation of the cable drum D starts to slow down, the frictional force that pushes the brake roller 5 toward the brake valve 12 gradually decreases. When this frictional force falls below a certain field value, the biasing force of the coil spring 11 overcomes the frictional force and pushes the outer case 6 back to its original position. Therefore, the outer case 6 returns to the initial position shown in FIG. 6, and at this time, the rod 6c also separates from the brake valve 12, so that the spool 12d also returns to the state of FIG. 9 and the internal flow passage is closed. As a result, the rotation of the brake roller 5 is stopped, so that the frictional force with respect to the cable drum D that is in contact with the peripheral surface of the brake roller 5 is increased, and the cable drum D is braked and stopped immediately.

In this way, when the rotation of the cable drum D becomes slow, that is, when the force pulling the cable C becomes weak or becomes zero, the brake roller 5 automatically stops its rotation, and the brake roller 5 is stopped. It can act as a resistance and stop this. Therefore, when the feeding of the cable C is stopped in the middle of the crossing work, the cable drum D also immediately stops rotating, and the cable C does not droop greatly between the electric poles. Further, since the cable drum D can be automatically stopped, it is not necessary for an operator to wait on the feeding side to watch and to stop the rotation with a bar or the like.

The brake roller 5 and the brake valve 12 can also be used to feed the cable C 1 while applying a substantially constant tension thereto. That is, when the rotation of the cable drum D becomes slow, the force pushing the brake roller 5 toward the brake valve 12 also becomes weak, and the plunger 12e moves to the right in FIG. Therefore, the flow passage area due to the valve body portion 12h is reduced, and the rotation of the hydraulic motor 10 is also attenuated. Therefore, the rotation speed of the break roller 5 also decreases, and the driving force for rotating the cable drum D also decreases. Therefore, if the pulling force of the cable C is weakened, the pulling force of the cable drum D also weakens, so that the pulled-out cable C is always fed with a uniform tension.

[0041]

[Effect of the device]

 In the present invention, the rotation of the cable drum can be immediately stopped when the feeding of the cable is stopped. For this reason, even when temporarily suspending the extension of the cable during the crossover work, the cable does not drastically hang down between the electric poles and the steel towers, it does not damage the house and the work can be done safely. .. In addition, it can be used not only for paying out the cable but also for winding up, so that one device can be effectively used.

[Brief description of drawings]

FIG. 1 is a side view showing an essential part of a rotation supporting device for a cable drum according to the present invention.

FIG. 2 is a schematic front view of the rotation support device when the cable drum is set.

FIG. 3 is a front view showing the arrangement of brake rollers of the rotation support device.

FIG. 4 is a schematic side view showing a state in which a cable drum is placed on a brake roller and set.

FIG. 5 is a schematic plan view showing an arrangement of a brake roller and a drive valve unit.

FIG. 6 is a cutaway side view showing a structure for incorporating a brake roller into a base.

FIG. 7 is a vertical cross-sectional view showing a brake roller and its support structure.

FIG. 8 is a schematic view showing a positional relationship between respective cores of a brake roller and a cable drum.

FIG. 9 is a vertical sectional view of a drive valve unit.

FIG. 10 is a perspective view of a main part of a spool included in the drive valve unit.

FIG. 11 is a hydraulic circuit diagram of the entire rotation support device,
It is a figure which shows operation which lowers the rod of a cylinder.

FIG. 12 is a hydraulic circuit diagram when an operation of raising a cylinder rod is performed.

FIG. 13 is a hydraulic circuit diagram when a pressure contact force between a cable drum and a brake roller is adjusted by a pressure adjusting valve.

FIG. 14 is a hydraulic circuit diagram when the cable drum can be rotationally driven by the rotation of the hydraulic motor.

FIG. 15 is a diagram when a hydraulic circuit is formed between a brake valve and a hydraulic motor.

FIG. 16 is a schematic diagram for explaining a conventional cable crossing operation.

[Explanation of symbols]

 1 Base 2 Arm 3 Cylinder 4 Support Block 5 Brake Roller 6 Outer Case 7 Inner Case 8 Coil Spring 10 Hydraulic Motor 11 Coil Spring 12 Brake Valve 20 Hydraulic Pump 21 Tank C Cable D Cable Drum E Axis

Claims (1)

[Scope of utility model registration request] 1. An arm which rotatably supports a shaft of a cable drum and whose supporting point is movable up and down,
A brake roller that covers the cable drum from above and receives the peripheral surface thereof, a means for urging the brake roller in the direction of the contact portion with the cable drum, and a hydraulic motor that drives the brake roller to rotate in the forward and reverse directions, A brake valve provided in a hydraulic circuit to the hydraulic motor, wherein the brake roller is movable in a tangential direction of the cable drum while maintaining contact with a peripheral surface thereof due to friction received during rotation of the cable drum. , The brake valve is
A plunger for opening the built-in valve mechanism is projected to the outside, the movement of the brake roller is mechanically connected to the plunger, and the valve mechanism can be opened when the plunger is pushed. Rotating support device for cable drum.