JP2001176321A - Expansion mast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion mast that can be manipulated simply and without looseness without man-power. SOLUTION: An expansion mast 1 is equipped with a wire rope 36 coupled with a winch 39 and a motor 40 connected to the winch 39. The expansion mast can be expanded and contracted without man-power by rotating the motor 40 forward and reversely. The mast is provided with a tension detection means 42 for detecting the tension of the wire rope 36. The mast is also provided with a stop means for stopping the motor 40 when the tension detected by the tension detection means 42 becomes smaller than a tension preset by a coil spring 43 or the like. This makes it possible to stop the motor 40 by means of the tension detection means 42 and block looseness in the wire rope 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic mast, and is used for, for example, a floodlight.

[0002]

Heretofore, this type has been applied to first to fourth mast members slidably combined with each other in the vertical direction as shown in FIG. 1 of Japanese Utility Model Registration No. 3021789, for example. Each pulley is rotatably supported, and a wire rope is wound around these pulleys, and one end of the wire rope is fixed to the uppermost mast member, and the other end is manually operated via the lowermost mast member pulley. The mast member is sequentially extended by winding the wire rope with the winch from the state where the mast member is reduced, while the mast member is sequentially extended by pulling out the wire rope with the winch from the state where the mast member is extended. It is designed to shrink.

[0003] In such a conventional telescopic mast, if the wire rope is cut, the mast member falls down.
No. 138406 discloses a floodlight. As shown in FIG. 5 of the publication, this floodlight is provided with a locking device such that the uppermost mast member is fixed at the highest position in a telescopic mast that expands and contracts by a manual winch.

In such a conventional telescopic mast, particularly a telescopic mast used for a floodlight, a manual winch is used, and the handle of the winch is turned by hand. A long wire rope was required to extend, and when the extension was required, the wire rope had to be wound around the winch a lot, which was a heavy labor. Further, as the telescopic mast becomes higher, the weight of the mast member in the upper stage also increases, and a greater force is required to rotate the winch. In particular, since the telescopic mast of the floodlight is provided with an illuminating device or the like at the upper end, the weight of the illuminating device is also applied to the handle of the winch via the wire rope.

When the telescopic mast is slightly extended from the contracted state, a force corresponding to the weight of the raised mast member is applied to the wire rope to generate tension. On the other hand, since the upper mast member is supported by a stopper or the like when the telescopic mast is in the contracted state, no tension is applied to the wire rope, and when the wire rope is extended from this state, the wire rope becomes slack. When a large slack occurs, for example, when the wire rope wound around the winch is loosened by about one turn or more, the wire rope is caught by a projection provided on a mast member or the like, and the projection is damaged. There is a concern that the wire rope may not be wound during the next winding of the wire rope. In addition, since the wire rope passes through the inside of the mast member and the periphery of the winch is covered with the safety cover, the slack of the wire rope cannot always be visually recognized. Therefore, it is inevitable whether or not the wire rope has a slack depending on whether the telescopic mast is in the extended state or the contracted state.

[0006] Further, a brake is usually mounted to prevent the winch from rotating in the feeding direction by the tension of the wire rope, and the stretch mast can be held in an extended state by this brake. However, since the brake is not effective in the rotation of the drum in the winding direction, the drum continues to rotate in the unwinding direction from the contracted state of the telescopic mast, and the wire rope is wound backward in the winch, and the telescopic mast is not rotated. When is extended, it cannot be held in the extended state, and there is a possibility that the raised upper mast falls freely.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a telescopic mast capable of easily performing a telescopic / contracting operation without manual operation. A further object of the present invention is to provide a telescopic mast that can easily and surely perform the extension / reduction operation without the adverse effects caused by the slack of the wire rope.

[0008]

According to the first aspect of the present invention, there are provided a plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, and these pulleys. A wire rope connected to a winch via a pulley of the lowermost mast member and one end fixed to the uppermost mast member, and a motor connected to the winch. Is a telescopic mast.

Therefore, according to the first aspect of the present invention, the retractable mast can be extended or contracted by winding or unwinding the wire rope by rotation of the motor.

According to a second aspect of the present invention, there are provided a plurality of mast members which are slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, Is fixed to the uppermost mast member and the other end is connected to a winch via a pulley of the lowermost mast member, a motor connected to the winch, and a tension detecting means for detecting a tension of the wire rope. And a stop means for stopping the motor when the tension detected by the tension detecting means becomes smaller than a preset tension.

Therefore, in the second aspect of the present invention, when the detected tension of the wire rope detected by the tension detecting means becomes smaller than a preset tension, the motor is stopped and the feeding of the wire rope is stopped.

According to a third aspect of the present invention, the tension detecting means includes a pulley movable in a direction in which the tension of the wire rope is combined, and a pulley in a direction opposite to the direction in which the tension of the wire rope is combined. An urging means for urging, and a limit switch which operates in accordance with a moving position of the pulley; and the stopping means, wherein the pulley is moved by the limit switch so that the pulley resists the urging force of the urging means. When it is detected that the motor has moved in the direction in which the tension is combined, the mast member of the motor is allowed to rotate in a downward direction, and the pulley is moved by the limit switch in the direction in which the tension of the wire rope is combined in accordance with the urging means. 3. The telescopic device according to claim 2, wherein upon detecting that the motor has moved in the opposite direction, the motor stops rotating in a direction in which the mast member descends. It is a door.

According to the third aspect of the present invention, when the pulley moves in a direction opposite to the direction in which the tension of the wire rope is combined according to the urging force of the urging means, the limit switch detects this movement, and By stopping the rotation in the direction in which the mast member descends, the feeding of the wire rope can be stopped.

According to a fourth aspect of the present invention, the pulley of the tension detecting means also serves as the pulley of the lowermost mast member and moves a predetermined amount in the vertical direction to urge upwardly against the tension of the wire rope. 4. The telescopic mast according to claim 3, wherein the mast is supported by an elastic body serving as the urging means.

Therefore, according to the present invention, when the tension of the wire rope is higher than the set value based on the urging force of the elastic body, the pulley moves downward, and the tension of the wire rope is set at the set value based on the urging force of the elastic body. If it is lower than this, the pulley moves upward and the moving position of the pulley can be detected.

According to the fifth aspect of the present invention, the tension detecting means is attached to the lowermost mast member, and is movable in a direction in which the tension of the wire rope is combined, and is provided with an idler that contacts and guides the wire rope. Biasing means for biasing the idler in a direction opposite to the direction in which the tension of the wire rope is combined; and a limit switch that operates in accordance with the position of movement of the idler; When the switch detects that the idler has moved in the direction in which the tension of the wire rope is combined against the urging force of the urging means, the motor allows the mast member to rotate in a downward direction, and the limit When the switch detects that the idler has moved in the direction opposite to the direction in which the tension of the wire rope is combined according to the urging force of the urging means, A telescoping mast of claim 2, wherein said mast member of the motor stops rotating in the direction of lowering.

Therefore, when the idler moves in the direction opposite to the direction in which the tension of the wire rope is combined according to the urging force of the urging means, the movement of the idler is detected by the limit switch. By stopping the rotation in the direction in which the mast member descends, the feeding of the wire rope can be stopped.

In the invention according to claim 6, the winch is attached to a side surface of a lowermost mast member so as to be movable by a predetermined amount in a vertical direction which is a substantially tension direction of the wire rope, and the tension detecting means is provided for the winch. A limit switch that operates in accordance with the movement position, and wherein the stopping means detects that the winch has been moved upward by the tension of the wire rope by the limit switch, so that the mast member of the motor moves in a downward direction. 3. The telescopic mast according to claim 2, wherein rotation is enabled, and when the limit switch detects that the winch has moved downward according to its own weight, the motor stops rotating in a direction in which the mast member descends. It is.

Therefore, according to the invention of claim 6, when the winch moves downward according to the weight of the winch, the limit switch detects this movement and stops the rotation of the motor in the direction in which the mast member descends. The feeding of the wire rope can be stopped.

According to a seventh aspect of the present invention, there are provided a plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, A wire rope fixed to the upper mast member and the other end connected to the winch via the pulley of the lower mast member, a motor connected to the winch, and detecting that the upper mast member is at the lowest position. And a stop means for stopping the motor when the position detecting means detects that the upper mast member is at the lowest position.

Therefore, according to the present invention, the rotation of the motor can be stopped by detecting that the upper mast member is at the lowest position, and the feeding of the wire rope can be stopped.

According to the present invention, the position detecting means fixes the proximity switch to the lowermost mast member, provides a detection surface of the proximity switch on the uppermost mast member, and the stopping means is provided by the proximity switch. When it is detected that the proximity switch and the detection surface provided on the uppermost mast member are separated from each other, the motor allows the mast member to rotate in a downward direction, and the proximity switch and the uppermost mast member are rotated by the proximity switch. 8. The telescopic mast according to claim 7, wherein upon detecting that a detection surface provided on the mast member is close to the mast member, the motor stops rotating in a direction in which the mast member is lowered.

Therefore, in the invention according to claim 8, the proximity switch detects that the detection surface has approached the proximity switch, stops the rotation of the motor in the direction in which the mast member descends, and extends the wire rope. Can be stopped.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 to 9 show a first embodiment. This telescopic mast 1 is used for a floodlight used for nighttime lighting at a civil engineering work site as shown in FIG. The trolley 2 has a plurality of wheels 3. In addition, a generator 5 which is a power supply of the lighting device 4 is mounted on the carriage 2, and a telescopic mast 1 is provided upright. The lighting device 4 is provided at an upper end of the telescopic mast 1.
Is provided. The lighting device 4 includes a plurality of lamps 6.
And a lamp turning mechanism 7 for rotating the lamp 6 horizontally and a lamp elevation / adjustment angle adjusting device 8 for rotating the lamp 6 vertically.

Next, the structure of the telescopic mast 1 will be described with reference to FIGS. The telescopic mast 1 is composed of five first to fifth mast members 11 to 15 that gradually become thinner and slidably combined with each other. A thin mast member 12 to 15 is provided inside the thick mast members 11 to 14. It is constructed so that it can be inserted sequentially and stretched vertically. Among them, the first mast member 11 which is the lowermost mast member is fixed to the carriage 2, and the lighting device 4 is attached to the upper end of the fifth mast member which is the uppermost mast member. Make the mast member on the upper stage about ~ 15. And the telescopic mast 1 is a pulley
21 to 35, driven by an expansion / contraction mechanism 38 including a wire rope 36 and a winch device 37 to expand and contract.
Although not shown, the upper limit of the mast members 12 to 15 inside the mast members 11 to 14 is
The stoppers provided at the lower portions of the mast members 12 to 15 abut against the stopper receivers provided at the upper portions of the mast members 12 to 15 from below.

The pulleys 21... 35 are two on the upper part of the first mast member 11 (the pulleys 21 and 23), and two on the upper and lower parts of the second mast member 12, the third mast member 13 and the fourth mast member 14. One each (pulleys 22, 24,..., 33, 35) is provided below the fifth mast member 15 (pulley 34). Any pulley 21… 35
Also, the rotation axis direction is provided horizontally. And
The wire rope 36 is fixed to the fixing portion 36 at the lower part of the fifth mast member 15
A is fixed at one end to the pulley 35 at the upper part of the fourth mast member 14, the pulley 34 at the lower part of the fifth mast member 15, the pulley 33 at the upper part of the fourth mast member 14, and the lower part of the fourth mast member 14. The pulley 32, the pulley 31 above the third mast member 13, the pulley 30 below the fourth mast member 14, the pulley 2 above the third mast member 13
9, the pulley 28 below the third mast member 13, the second mast member 1
2, a pulley 27 at the upper part, a pulley 26 at the lower part of the third mast member 13,
The pulley 25 at the upper part of the second mast member 12, the pulley 24 at the lower part of the second mast member 12, the pulley 23 at the upper part of the first mast member 11, the second
The pulley 22 at the lower part of the mast member 12 and the pulley 21 at the upper part of the first mast member 11 are stretched in this order. The wire rope 36 is located inside the mast members 11 to 14, but is led out of the pulley 21 and the other end is connected to the winch 39 of the winch device 37.

Therefore, when the wire rope 36 is pulled out of the telescopic mast 1 from the contracted state of the telescopic mast 1 and the wire rope 36 is wound around the winch 39, the innermost fifth mast member 15 first rises. And then fourth, third,
The second mast members 14, 13, 12 are sequentially raised in this order, and the telescopic mast 1 is in an extended state as shown in FIG.
When the wire rope 36 is drawn out of the winch 39 from the state where the telescopic mast 1 is extended, and the wire rope 36 is returned into the telescopic mast 1, first, the second mast member 1 is moved by gravity.
2, the third mast member 13 and the fourth mast member 14 are sequentially lowered, and finally the innermost fifth mast member 15 is lowered, and the telescopic mast 1 is in a contracted state.

Further, the winch device 37 enables a winch 39 for winding and unwinding the wire rope 36 to be rotated by an electric, hydraulic or pneumatic motor 40. In this embodiment, a configuration in which the winch 39 is rotated by the electric motor 40 will be described. When the operation switch 41, which is an operation unit, is operated to “up” and the motor 40 is rotated to one side, the telescopic mast 1 is extended by winding the wire rope 36, and the operation switch 41 is operated to “down” to operate the motor. When the lever 40 is rotated to the other side, the wire rope 36 is extended, and the telescopic mast 1 is reduced.

Further, in order to eliminate the adverse effects caused by the slack of the wire rope 36, a tension detecting means 42 for detecting the tension of the wire rope 36 is provided, and the detected tension of the tension detecting means 42 is smaller than a preset tension. When it comes to the motor 40
There is provided a stopping means described later for stopping the operation. The tension detecting means
Reference numeral 42 denotes a pulley 21 provided above the first mast member 11 so as to be vertically movable with respect to the first mast member 11, and the pulley 21 is urged upward by an elastic body to move the pulley 21. In this configuration, the tension of the wire rope 36 can be detected from the position. The pulley 21 is supported by a pair of left and right brackets 46 erected from a bottom plate 45 via a center shaft 44 penetrating the center of the pulley 21. On the lower surface of the bottom plate 45, an operating shaft 48 for operating a limit switch 47 described later projects downward. At a position below the vertical hole 11A, a mounting plate 49 having a guide projecting piece 50 that projects horizontally with respect to the first mast member 11 and has a guide hole 50A through which the operating shaft 48 is inserted is mounted. . By mounting the coil spring 43 on the operating shaft 48 and inserting the coil spring 43 into the guide hole 50A, the upper end of the coil spring 43 contacts the lower surface of the bottom plate 45, the lower end contacts the upper surface of the guide extension piece 50, and the lower end of the operating shaft 48 Project from the lower surface of the guide overhanging piece 50. A square plate 48A is mounted from below the operating shaft 48, and one side of the square plate 48A is fitted into a groove 49A provided in the mounting plate 49, and a snap ring 48B is engaged with a lower end of the operating shaft 48. I do. Accordingly, the coil spring 43 urges the pulley 21 upward, and the square plate 48A prevents the pulley 21 from touching left and right. A bracket 49B for mounting a limit switch 47 is provided below the guide extension piece 50 so as to protrude from the mounting plate 49. When the limit switch 47 is mounted, the bracket 49B contacts the lower end surface of the operating shaft 48. The actuator 47A is located so as to be opposed. And a safety cover around the pulley 21 and winch 39
11B is provided.

FIG. 7 shows an electric circuit diagram as stopping means for stopping the motor 40 in response to the limit switch 47.
AC power is supplied from the generator 5 to the motor 40 provided on the winch 39 via a control circuit 40A. A limit switch 47 is connected to the control circuit 40A. Further, an operation switch 41 is connected to the control circuit 40A. The relay 47B of the limit switch 47 is connected. The control circuit 40A converts AC power supplied from the generator 5 to DC, and performs manual operation of the operation switch 41 and a limit switch 47.
With the operation of the relay 47B, the direction of the current supplied to the motor 40 and, consequently, the rotation direction can be switched. When the limit switch 47 is opened in a state where the operation switch 41 is located at the middle position in FIG.
The motor 40 stops without any short circuit between any of the above a to d, and even if the limit switch 47 is closed, the control circuit 40A
There is no short circuit between any of a to d, and the motor 40 is in a stopped state. When the limit switch 47 is opened in a state where the operation switch 41 is in the up position, the a-b in the control circuit 40A is short-circuited, the telescopic mast 1 is raised by the motor 40, and even if the limit switch 47 is closed. Control circuit 40A
And the mast 1 is raised by the motor 40. Further, when the limit switch 47 is opened with the operation switch 41 in the lowered position, a short circuit occurs between a and c in the control circuit 40A and the motor 40 stops, and when the limit switch 47 is closed, a in the control circuit 40A is closed.
-D is short-circuited, and the telescopic mast 1 is contracted by the motor 40. That is, regardless of the state of the limit switch 47, the motor 40 rotates so as to extend on the telescopic mast 1 when the operation switch 41 performs the upward operation, and when the operation switch 41 performs the downward operation, the limit switch 47 When the motor 47 is open, the motor 40 stops, and when the motor 47 is closed, the motor 40 rotates so as to contract on the telescopic mast 1.

Since the extension and contraction of the telescopic mast 1 have been described in detail above, the operation and effect of the tension detecting means 42 and the limit switch 47 as the stopping means will be described. When the operation switch 41 is operated to “up” and the telescopic mast 1 is slightly extended from the reduced state, one end of the wire rope 36 is fixed to the fixing portion 36A of the fifth mast member, and the wire rope 36 is connected to the second mast member. Since it is wound around the pulleys 22 of the members 12 and wound around the winch 39, the wire rope 36
At one end of the second to fifth mast members 12, 13, 14,
A weight of 15 and a lifting force of a winch 39 are applied to the other end, and tension is generated on the entire wire rope 36. For this reason, a pulling force applied to the other end of the wire rope 36 and a pulling force toward the pulley 22 under the second mast member 12 are applied to the pulley 21 provided at the upper end of the first mast member 11. Therefore, the pulley 21 and the bracket 46 are guided by the guide hole 50 of the guide extension piece 50 by the tension of the wire rope 36 which exceeds the urging force of the coil spring 43.
Move down along A. When the pulley 21 is moving downward as described above, the lower end surface of the operating shaft 48 presses the actuator 47A of the limit switch 47, and the actuator 47A is pressed by a predetermined amount. If so, the contact is closed. While maintaining this state, the wire rope 36 is wound around the winch 39, and the telescopic mast 1 rises and extends.

On the other hand, when the operation switch 41 is operated to "down" and the mast 1 is changed from the extended state to the contracted state, the second to fifth mast members 12, 13, 14, 15 are stopped by stoppers or the like.
And the wire rope 36 receives almost no tension. When the wire rope 36 is further extended from the winch 39 in such a state, the pulley 21 and the bracket 46, which have moved downward, are attached to the wire rope 36.
In conjunction with the extension of 36, the coil spring 43 gradually moves upward due to the urging force of the coil spring 43. As a result, the operating shaft 48 integrated with the pulley 21 and the bracket 46 slides upward along the guide hole 50A of the guide extension piece 50. The actuator 47A of the limit switch 47 pressed on the lower end surface gradually returns, and returns by a predetermined amount. For example, in the case of a normally open type limit switch 47, its contact is opened and the motor 40 is automatically turned on. Can be stopped. Therefore, when the wire rope 36 is extended while the telescopic mast 1 is extended to bring the telescopic mast 1 into the contracted state, the wire rope
Since the motor 40 can be automatically stopped before the sag becomes loose and its feeding can be stopped, the wire rope 36 is not caught or entangled, and the wire rope 36 can be prevented from being reversely wound in the winch 39. .

Further, even if the lower mast member, for example, the fourth mast member 14 and the upper mast member, for example, the fifth mast member 15 are caught in the middle of the contraction of the telescopic mast 1 and the contraction is stopped, the operation switch 41 is stopped. If the wire rope 36 wound around the winch 39 is further extended, the pulley 21 moves upward by the urging force of the coil spring 43 because the tension of the wire rope 36 is weakened. The movement causes the limit switch 47 to return and the motor 40 to stop automatically, so that the wire rope 36 does not sag. Therefore, thereafter, the lower mast members 11, 12, 13, 14 and the upper mast members 12, 13, 14,
When the hook 15 is released, it is possible to prevent the upper mast member from falling freely and prevent the wire rope 36 from being damaged, the pulleys 21... And the mast members 11, 12, 13, 14, 15 from being damaged.

As described above, in the above embodiment, the first to fifth mast members 11 slidably combined with each other in the vertical direction.
35, the pulleys 21... 35 rotatably supported by these mast members 11 to 15, and one end fixed to the fifth mast member 15 and A wire rope 36 connected to the winch 39 via the pulley 21 of the member 11; and a motor 40 connected to the winch 39, and the motor 40 is rotated forward in a direction in which the mast members 12 to 15 rise. The telescopic mast 1 is extended without using human power by the reverse rotation in which the mast members 12 to 15 descend,
Can be reduced.

Further, a tension detecting means 42 for detecting the tension of the wire rope 36 is provided, and when the detected tension of the tension detecting means 42 becomes smaller than the tension set in advance by a coil spring 43 or the like, the motor 40 is stopped. By providing the stopping means, when the wire rope 36 sags and the tension of the wire rope 36 is reduced, this is detected and the mast members 12 to 15 of the motor 40 and eventually the winch 39 are detected.
However, since the rotation in the descending direction is stopped, the slack of the wire rope 36 can be prevented.

Further, the tension detecting means 42 detects the direction in which the tension of the wire rope 36 is combined, that is, the pulley 21 movable in the vertical direction, and the pulley 21 with respect to the direction in which the tension of the wire rope 36 is combined. The pulley 21 is provided with a coil spring 43 biased in the opposite direction, that is, upwardly, and has a limit switch 47 that is operated in accordance with the moving position of the pulley 21. The direction in which the tension of the wire rope 36 is combined against the urging force of 43, that is, when it is detected that the pulley 21 has moved downward, the motor 40 can be rotated in the direction in which the mast members 12 to 15 descend, The limit switch
When the pulley 21 detects that the pulley 21 has moved in the opposite direction to the direction in which the pulley 21 has combined the tension of the wire rope 36 according to the urging force of the coil spring 43, that is, the pulley 21 has moved upward, the mast members 12 to 15 of the motor 40 descend. By stopping the rotation in the direction, the pulley 21 was moved in the vertical direction depending on the strength of the wire rope 36, and the limit switch 47 was operated with the movement of the pulley 21, so that
The tension of the wire rope 36 can be directly transmitted to the limit switch 47, and the slack of the wire rope 36 can be reliably prevented.

Next, second to fourth embodiments of the present invention will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The tension detecting means 51 according to the second embodiment shown in FIGS. 10 and 11 contacts the wire rope 36 between the pulley 21 and the winch 39 on the side surface of the first mast member 11.
An idler 52 is provided for guiding the outer side, that is, the side opposite to the side surface of the first mast member 11. The idler 52 has a horizontal axis, and the opening side is the first mast member 11.
The bracket 53 is rotatably provided at the upper end of a front U-shaped bracket 53 facing the side surface of the wire rope 36, and the bracket 53 is placed on a mounting plate 54 protruding from the side surface of the first mast member 11. Are movable in the direction obtained by combining them, that is, in the embodiment, the first mast member 11 is provided so as to be movable forward and backward. Then, the lower end of the bracket 53 is inserted into the lateral hole 56 of the guide member 55 on the mounting plate 54. Further, the bracket 53 and, consequently, the idler 52 are provided with a coil spring 57 which is a biasing means for biasing the wire rope 36 in a direction opposite to the direction in which the tension of the wire rope 36 is combined, that is, in a direction opposite to the side surface of the first mast member 11. The coil spring 57 is interposed below the bracket 53 and has one end locked to a vertically intermediate portion of the bracket 53 and the other end locked to the guide member 55. An actuator 58A of the limit switch 58 is fixed on the mounting plate 54 so as to face the lower end of the bracket 53.

Therefore, when the telescopic mast 1 is reduced by operating the operation switch to "down" while the telescopic masts 11 to 15 are extended, the second to fifth mast members 12, 13, 14 are stopped by stoppers or the like. , 15 and the wire rope 36 is hardly subjected to tension. Further, when the wire rope 36 is pulled out from the winch 39, the idler 52 which has been moved inward by the tension of the wire rope 36 becomes Of the idler 52 as a result, the spring is gradually moved outward by the urging force of the coil spring 57.
The actuator 58A of the limit switch 58, which has been pressed by the lower end of the bracket 53 integrated with
After the return by the predetermined amount, the contact of the limit switch 58 is closed (or opened), and the motor 40 can be automatically stopped. Accordingly, when the telescopic mast 1 is extended and the wire rope 36 is extended to bring the telescopic mast 1 into a contracted state, the motor 40 is automatically stopped before the wire rope 36 sags and the extension is performed. Since the stop can be stopped, even if the lower mast member, for example, the fourth mast member 14 and the upper mast member, for example, the fifth mast member 15 are caught in the middle of the reduction of the telescopic mast 1 and the reduction is stopped, the operation switch is set to “ If the operation is continued to “down”, the wire rope 36 wound on the winch 39 is further extended, but the tension of the wire rope 36 is weakened, so that the idler 52 is
The limit switch 58 is returned by this movement, and the motor 40 can be automatically stopped.

The tension detecting means 61 of the third embodiment shown in FIG.
The wire rope 36 is wound up through the pulley 21 and the base plate 63 of the winch bracket 62 integral with the winch 39 to be fed out is attached to the winch mounting plate 64 provided on the side surface of the first mast member 11 by the tension of the wire rope 36. Movably in the vertical direction, that is, in the vertical direction. In this example, a vertically long hole 65 is provided in a winch mounting plate 64, and a bolt 66 as an elevating mounting shaft fixing the base plate 63 is loosely inserted into the long hole 65, and a nut 66A is mounted. Further, a detecting portion 62A is provided at an upper portion of the winch bracket 62 so as to protrude upward, and an actuator 67A of a limit switch 67 is attached via the bracket 68 so as to face the detecting portion 62A. When the limit switch 67 detects that the winch 39 has moved in the direction of the tension of the wire rope, that is, has moved upward, the mast member of the motor 40 is detected.
When the limit switch 67 detects that the wire has moved downward in the direction opposite to the direction of tension of the wire rope 39, that is, when the limit switch 67 has moved downward according to the weight of the winch 39, the mast member of the motor 40 is controlled. It is configured to stop rotation in the direction in which 12 to 15 descend.

Therefore, when the operation switch is operated to "down" while the telescopic mast 1 is extended and the telescopic mast 1 is reduced, the second to fifth mast members 12, 13, 14, 14, When the wire rope 36 is pulled out from the winch 39, the wire rope 36
The winch 39, which had been moving upward due to the tension of 36, gradually moved downward due to the weight of the winch 39 in conjunction with the feeding of the wire rope 36, and as a result, was pressed by the detection unit 62A integral with the winch 39. When the actuator 67A of the limit switch 67 gradually returns and returns by a predetermined amount, the contact of the limit switch 67 closes (or opens), and the motor 40 can be automatically stopped. Therefore,
When the telescopic mast 1 is extended and the wire rope 36 is extended to make the telescopic mast 1 in a contracted state, the motor 40 is automatically stopped before the wire rope 36 sags and the extension is stopped. Even if the lower mast member, for example, the fourth mast member 14 and the upper mast member, for example, the fifth mast member 15 are caught in the middle of the contraction of the telescopic mast 1 and the contraction is stopped, the operation switch is set to “down”. ”, The wire rope wound on winch 39
Although the wire 36 is further extended, the winch 39 moves downward by its own weight because the tension of the wire rope 36 is weakened. This movement causes the limit switch 67 to return, and the motor 40 can be stopped automatically.

In the fourth embodiment shown in FIG. 13, the position detecting means 70 for detecting that the fifth mast member 15, which is the upper mast member, is in the lowest position, that is, in the contracted state, and the position detecting means 70 A stop means for stopping the motor 40 when the mast member 15 detects that the mast member 15 is at the lowermost position, that is, in a contracted state;
70 is a bracket in which the proximity switch 72 is fixed to the first mast member 11 via the bracket 71, and the detection surface 73 of the proximity switch 72 is provided downward on the uppermost mast member, that is, the fifth mast member 15. It is provided via 74. On the other hand, the stopping means is provided by the proximity switch 72.
When it is detected that the detection surface 73 of the fifth mast member 15 is separated from the mast member 72, the motor 40 can be rotated in a direction in which the mast members 12 to 15 are lowered, and the proximity switch 72 When the detection surface 73 provided on the fifth mast member 15 is detected to be close, the motor 40 cannot rotate in the direction in which the rotation of the mast members 12 to 15 is lowered.

Therefore, when the operation switch is operated to “down” while the telescopic mast 1 is extended and the telescopic mast 1 is reduced, the detection surface 73 is lowered together with the fifth mast member 15 and the proximity switch is moved. When the proximity of the wire rope 36 is detected, the proximity switch 72 detects this, and the motor 40 is automatically stopped, so that the feeding of the wire rope 36 can be stopped and the slack of the wire rope 36 can be prevented.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0045]

According to the first aspect of the present invention, a plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, and a pulley spanned over these pulleys. A telescopic mast comprising: a wire rope having one end fixed to the uppermost mast member and the other end connected to the winch via a pulley of the lowermost mast member; and a motor connected to the winch. And
Winding or unwinding of the wire rope by rotation of the motor makes it possible to easily expand or contract the telescopic mast.

According to a second aspect of the present invention, there are provided a plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, Is fixed to the uppermost mast member and the other end is connected to a winch via a pulley of the lowermost mast member, a motor connected to the winch, and a tension detecting means for detecting a tension of the wire rope. And a stop means for stopping the motor when the tension detected by the tension detecting means becomes smaller than a preset tension, wherein winding or unwinding of the wire rope is performed by rotation of the motor. To easily expand or contract the telescopic mast,
When the detected tension of the tension detecting means becomes smaller than a preset tension, the motor is stopped, the feeding of the wire rope is stopped, and the adverse effects associated with the slack of the wire rope can be eliminated, and the wire can be easily and reliably extended. A reduction operation can be performed.

According to a third aspect of the present invention, the tension detecting means comprises: a pulley movable in a direction in which the tension of the wire rope is combined; and a pulley moving the pulley in a direction opposite to the direction in which the tension of the wire rope is combined. An urging means for urging, and a limit switch which operates in accordance with a moving position of the pulley; and the stopping means, wherein the pulley is moved by the limit switch so that the pulley resists the urging force of the urging means. When it is detected that the motor has moved in the direction in which the tension is combined, the mast member of the motor is allowed to rotate in a downward direction, and the pulley is moved by the limit switch in the direction in which the tension of the wire rope is combined in accordance with the urging means. 3. The telescopic device according to claim 2, wherein upon detecting that the motor has moved in the opposite direction, the motor stops rotating in a direction in which the mast member descends. It is the windows, and the pulley is moved in the direction opposite to the direction obtained by synthesizing the tension of the wire rope,
This movement is detected by the limit switch, the rotation of the motor in the direction in which the mast member descends is stopped, the feeding of the wire rope is stopped, and the adverse effects associated with the slack of the wire rope can be eliminated. In addition, the expansion and contraction operations can be performed reliably.

According to the fourth aspect of the present invention, the pulley of the tension detecting means also functions as the pulley of the lowermost mast member and moves a predetermined amount in the vertical direction, and urges the pulley upward against the tension of the wire rope. 4. The telescopic mast according to claim 3, wherein the pulley moves downward when the tension of the wire rope is higher than a set value based on the urging force of the elastic body. If the tension of the wire rope is lower than the set value based on the biasing force of the elastic body, the pulley moves upward and the limit switch detects the moving position of the pulley, which can eliminate the adverse effect associated with the slack of the wire rope, The extension and reduction operations can be performed easily and reliably.

According to a fifth aspect of the present invention, the tension detecting means is attached to the lowermost mast member, and is movable in a direction in which the tension of the wire rope is combined, and is provided with an idler for contacting and guiding the wire rope. Biasing means for biasing the idler in a direction opposite to the direction in which the tension of the wire rope is combined; and a limit switch that operates in accordance with the position of movement of the idler; When the switch detects that the idler has moved in the direction in which the tension of the wire rope is combined against the urging force of the urging means, the motor allows the mast member to rotate in a downward direction, and the limit When the switch detects that the idler has moved in the direction opposite to the direction in which the tension of the wire rope is combined according to the urging force of the urging means, 3. The telescopic mast according to claim 2, wherein the mast member of the motor stops rotating in a descending direction, wherein the idler is combined with the tension of the wire rope in accordance with the urging force of the urging means. When it moves in the opposite direction, the limit switch detects this movement, stops the rotation of the motor in the direction in which the mast member descends, stops the feeding of the wire rope, and eliminates the adverse effects associated with the slack of the wire rope. The extension and reduction operations can be performed easily and reliably.

In the invention according to claim 6, the winch is mounted on a side surface of the lowermost mast member so as to be movable by a predetermined amount in a vertical direction which is a substantially tension direction of the wire rope, and the tension detecting means is provided for the winch. A limit switch that operates in accordance with the movement position, and wherein the stopping means detects that the winch has been moved upward by the tension of the wire rope by the limit switch, so that the mast member of the motor moves in a downward direction. 3. The telescopic mast according to claim 2, wherein rotation is enabled, and when the limit switch detects that the winch has moved downward according to its own weight, the motor stops rotating in a direction in which the mast member descends. When the winch moves downward according to the weight of the winch, the movement is limited by the limit switch. Is detected, the rotation of the motor in the direction in which the mast member descends is stopped, the feeding of the wire rope is stopped, and the adverse effects associated with the slack of the wire rope can be eliminated. A reduction operation can be performed.

According to a seventh aspect of the present invention, a plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, and A wire rope fixed to the upper mast member and the other end connected to the winch via the pulley of the lower mast member, a motor connected to the winch, and detecting that the upper mast member is at the lowest position. A telescopic mast, comprising: a position detecting means for detecting the position of the upper mast member at the lowest position by the position detecting means; The retractable mast can be easily extended or contracted by winding or unwinding the wire rope, and it detects that the upper mast member is at the lowest position. Stop the rotation of the motor Te, stop feeding of the wire rope, it is possible to eliminate the harmful effects caused by the slack of the wire rope, easily and reliably extension can perform reduction operation.

In the eighth aspect, the position detecting means fixes a proximity switch to the lowermost mast member, provides a detection surface of the proximity switch on the uppermost mast member, and the stopping means is provided by the proximity switch. When it is detected that the proximity switch and the detection surface provided on the uppermost mast member are separated from each other, the motor allows the mast member to rotate in a downward direction, and the proximity switch and the uppermost mast member are rotated by the proximity switch. The telescopic mast according to claim 7, wherein the rotation of the mast member in the direction in which the mast member descends is stopped upon detecting that the detection surface provided on the mast member has come close to the mast member. Detecting that the detection surface has approached the proximity switch, stopping rotation of the motor in the direction in which the mast member descends, and turning the wire rope Stop teeth, can be eliminated adverse effects associated with the slack of the wire rope, easily and reliably extension can perform reduction operation.

[Brief description of the drawings]

FIG. 1 is an overall front view showing a first embodiment of the present invention.

FIG. 2 is a front view of a main part showing the first embodiment of the present invention.

FIG. 3 is a side view of a main part showing the first embodiment of the present invention.

FIG. 4 is a front sectional view of a main part showing the first embodiment of the present invention.

FIG. 5 is a side sectional view of a main part showing the first embodiment of the present invention.

FIG. 6 is an exploded perspective view showing the first embodiment of the present invention.

FIG. 7 is an electric circuit diagram showing a first embodiment of the present invention.

FIG. 8 is an explanatory diagram of a reduced state showing the first embodiment of the present invention.

FIG. 9 is an explanatory diagram of an extended state showing the first embodiment of the present invention.

FIG. 10 is a partially cutaway front view showing a second embodiment of the present invention.

FIG. 11 is a side view showing a second embodiment of the present invention.

FIG. 12 is a sectional view showing a third embodiment of the present invention.

FIG. 13 is a front view showing a fourth embodiment of the present invention.

[Explanation of symbols]

 11 12 13 14 15 Mast member 21 ... Pulley 36 Wire rope 39 Winch 40 Motor 42 51 61 Tension detection means 43 Coil spring (elastic body) 47 58 67 Limit switch 52 Idler 57 Coil spring (biasing means) 70 Position detection means 72 Proximity switch 73 Detection surface

Claims (8)

[Claims] 1. A plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, and a mast which is hung over these pulleys and whose one end is an uppermost stage. A telescopic mast comprising: a wire rope fixed to a member and the other end connected to a winch via a pulley of a lowermost mast member; and a motor connected to the winch. 2. A plurality of mast members which are slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, A wire rope fixed to the member, the other end of which is connected to the winch via a pulley of the lowermost mast member, a motor connected to the winch, tension detecting means for detecting the tension of the wire rope; A telescopic mast, further comprising a stopping means for stopping the motor when a detected tension of the means becomes smaller than a preset tension. 3. A pulley that is movable in a direction in which the tension of the wire rope is combined, and a bias that biases the pulley in a direction opposite to the direction in which the tension of the wire rope is combined. Means, and a limit switch that operates in accordance with the moving position of the pulley, wherein the stopping means is configured to control the direction in which the pulley combines the wire rope tension against the urging force of the urging means by the limit switch. When it is detected that the motor has moved, the mast member of the motor is allowed to rotate in a descending direction, and the pulley is moved in a direction opposite to a direction in which the pulley is combined with the tension of the wire rope according to the urging means by the limit switch. 3. The telescopic mast according to claim 2, wherein upon detecting that the mast member has moved, the motor stops rotating in a direction in which the mast member descends. 4. The biasing means of the tension detecting means, which also serves as a pulley of the lowermost mast member, moves vertically by a predetermined amount, and biases upward against the tension of the wire rope. The elastic mast according to claim 3, wherein the mast is supported by an elastic body. 5. An idler which is attached to a lowermost mast member, is movable in a direction in which the tension of the wire rope is combined, and guides the idler in contact with the wire rope. An urging means for urging the wire rope in a direction opposite to a direction in which the tension is combined, and a limit switch which operates in accordance with a position where the idler is moved, wherein the stopping means is configured such that the idler is operated by the limit switch. When it is detected that the wire has moved in the direction in which the tension of the wire rope is combined against the urging force of the urging means, the mast member of the motor is allowed to rotate in a downward direction, and the idler is operated by the limit switch. When it is detected that the wire rope has moved in a direction opposite to the direction in which the tension of the wire rope is combined according to the urging force of the urging means, the mast of the motor is detected. 3. The telescopic mast according to claim 2, wherein the rotation of the member in a downward direction is stopped. 6. The winch is mounted on a side surface of a lowermost mast member so as to be movable by a predetermined amount in a vertical direction which is substantially a tension direction of the wire rope, and the tension detecting means is provided in accordance with a moving position of the winch. Operating the limit switch, the stopping means, when the limit switch detects that the winch has been moved upward by the tension of the wire rope, enables the motor to rotate in the direction in which the mast member descends, The telescopic mast according to claim 2, wherein when the limit switch detects that the winch has moved downward according to its own weight, the motor stops rotating in a direction in which the mast member descends. 7. A plurality of mast members slidably combined with each other in a vertical direction, a pulley rotatably supported by these mast members, and a mast which extends over these pulleys and has one end at the uppermost stage. A wire rope fixed to the member and having the other end connected to the winch via a pulley of the lowermost mast member, a motor connected to the winch, and position detection for detecting that the upper mast member is at the lowest position. And a stop means for stopping the motor when the position detection means detects that the upper mast member is at the lowest position. 8. The position detecting means fixes a proximity switch to a lowermost mast member, a detection surface of the proximity switch is provided on an uppermost mast member, and the stop means is provided by the proximity switch by the proximity switch. When it is detected that the detection surface provided on the uppermost mast member is separated from the uppermost mast member, the motor allows the mast member to rotate in a descending direction, and the proximity switch causes the proximity switch and the uppermost mast member to rotate. 8. The telescopic mast according to claim 7, wherein upon detecting that the provided detection surface has approached, rotation of the motor in the direction in which the mast member descends is stopped.