JP2635088B2 - Turning device for construction cranes - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction crane turning control device having a crane boom capable of extending and retracting and having a function of being able to move up and down.

BACKGROUND OF THE INVENTION A tower crane for construction that can be used by extending and retracting a boom is known, for example, from JP-A-62-16998. Such a crane can be used differently from a conventional tower crane having a structure in which the boom does not expand and contract. For example, it is possible to perform an operation of expanding and contracting while turning while the boom is horizontal. Of course, it is possible to freely change the turning radius and the hanging position by raising and lowering the boom.

As described above, although the mobility is higher than that of a crane provided with a boom having no telescopic function, the function is often restricted during work. In particular, when the installation site is narrow, such as in an urban area, the operation range is restricted due to the installation position of the crane, or when it is difficult to turn with the boom lengthened within the operation range, it is difficult to operate It is often necessary to limit the turn above. Imposing such restrictions on the driver can lead to excessive mental fatigue and reduced safety.

Problem to be solved: In the case of a tower crane for construction having a function of allowing the boom to expand and contract as described above, it is necessary to add restrictions to the function so that it can be handled according to the situation at the installation site. And safety is impaired. However, the conditions for imposing restrictions are not constant, and can be easily changed according to the situation of the work site (installation place), and can be set to a state that can reliably satisfy the use conditions in the required range. , Came to be required.

Means for Solving the Problems: The present invention relates to a construction of a control mechanism for a tower crane for construction having a boom having a telescopic function, by contracting the boom in a turning range that needs to be regulated out of all turning angles. An object of the present invention is to provide a control device for a crane that can be operated safely, with a control mechanism capable of restricting the operation conditions of the boom only between preset rotation angles so as not to cause a contact accident with the crane.

That is, the present invention relates to a control mechanism of a construction tower crane having a boom having a telescopic function; at least two limit switches for detecting a turning position are provided in association with a turning drive, and the boom has a tip or main segment. A limit switch for setting the length at which the boom contracts is provided at an appropriate position; the turning operation is performed by the turning position detecting limit switches provided at both outermost positions of the target regulating rotation angle among all the turning angles. At the same time, the boom telescopic drive is operated to contract the boom to the set length, and the boom can be operated in the contracted state in the section up to the next outermost turning position detection limit switch position. An electric control mechanism for restricting normal crane operation in the turning range is provided.

The limit switch for detecting the turning position is an operation piece that moves in a linear direction by receiving power from a small gear meshing with a gear of a fixed wheel in a turning mechanism of a crane, and is configured to operate limit switches positioned in parallel. Can be adopted. Needless to say, a limit switch (or operation piece) may be attached along the fixed side of the turning wheel, and a switch operation piece (or limit switch) may be attached to the revolving wheel to control the turning wheel.

The limit switch for setting the boom length attached to the extendable boom can be pre-installed before installation at the tip side of the main segment of the boom or on the side of the tip segment so that it can respond to the situation of the work site to be installed. To do. From the beginning, for example, it is also possible to provide an automatic setting type which is attached to, for example, a boom trunk segment so that the contraction limit can be set so as to be electrically changeable with other telescopic segments.

In the present invention, the normal crane operation is restricted within the range where the turning of the boom is restricted.

Action: In the tower crane provided with the control device of the present invention, a turning range for defining a normal crane operation in advance according to the conditions of the crane installation site is related to a turning mechanism. The limit switch for setting the contraction of the boom is set in advance to the minimum required for contraction.

Operating the crane in this state, for example, due to the convenience of the installation site, when the extending boom turns as it is, approaching the zone where there is a danger of colliding with the framework under construction or the existing building, The turning drive unit is stopped by the operation of the turning position detecting limit switch. Then, when the driver gives an instruction signal in the direction of contracting the extending boom, the boom is contracted by the retracting operation of the telescopic drive unit of the boom. When the boom reaches the previously set contraction length, the limit switch is actuated to stop the contraction. Thereafter, when working within the restricted range, crane work can be performed only when the boom is contracted.

If a turn operation is performed to escape from the turn restriction range, if the turn direction is one direction, the turn is made in the traveling direction and the position detection limit switch on the opposite side to the previous position is operated, thereby turning control. Exit the range.

After the turning movement outside the turning restriction range, normal crane operation can be freely performed.

Embodiments The following describes the present invention with reference to one embodiment.

FIG. 1 shows a boom telescopic construction tower crane 1 equipped with the turning restricting device of the present invention, and has a climbing mechanism 3. A swivel 6 is attached to the upper part of the crane support frame 4 fitted to the post 2 via a swivel mechanism 5 having a well-known structure, and a telescopic structure is provided at the upper end of a boom support frame 7 erected on the swivel 6. Boom 8
The base end is connected with a pin, and a hydraulic cylinder 9 for raising and lowering the boom is mounted between the base and the swivel 6. 10 is a hoist, 11 is a hanging line, and 12 is a hanging pulley block.

The turning control device 20 includes an electric control panel 15 mounted on the turning table 6.
(Electric control mechanism 30 attached to the control box)
(Described later) and a turning restriction range detecting mechanism attached to the turning table 6.
21 (see FIGS. 2 and 3), and a limit length setting limit switch 28 attached to the boom 8 as exemplified in FIG. 4 and an operation piece 9 thereof.

The turning restriction range detecting mechanism 21 includes a known screw limit switch 22 and a screw shaft 23 of the switch.
And a relay gear 26 meshing with a large gear 5 'provided on the turning fixed wheel, comprising:
The screw shaft 23 is rotated via a gear 26 "at the upper part of the shaft 26 'via a supporting shaft 26', a small gear 27 meshing therewith, a connecting shaft 27 ', and a pair of bevel gears 27". The turning position detecting switches 31 and 31 'for restricting the turning range are set in the switch box 22' to a position corresponding to the required turning angle, and are operated by operating pieces 32 which are screwed to the screw shaft 23 and moved. It is related that the electric control mechanism 30 is operated by turning on and off the 31, 31 '.

For example, when the boom 8 is formed by combining three segments, an operation piece 29 is attached to the end of the intermediate segment 8B as shown in FIG. 4 when the contraction length setting limit switch 28 attached to the boom 8 is used. A limit switch 28 is attached to each of the distal edges of the distal segment 8A and the backbone segment 8C so that the length of the boom 8 can be contracted in two stages. In the case of a two-piece boom, the operation piece is attached to either one of them.

The electric control mechanism 30 has a configuration as shown in FIG. 5, and in this figure, a control section relating to the operation of the crane is omitted. Symbols R1, R2, R3, R4, R5, R6, R in the figure
A and RB are relays respectively. KS is a keep relay. R2 ′, R3 ′,
R4 ', R5', R6 ', RA', RB 'are normally closed contacts of the relay. R
1 ", R3", R4 ", KS" are normally open contacts of the relay. PB1, PB2,
PB3 and PB4 are push button switches.

The turning restriction range detection mechanism described above is not limited to this, and a limit switch may be provided on one of the turning table and the crane unit support frame.
On the other hand, it is also possible to adopt a configuration in which a piece for operating the limit switch is attached to each.

Next, the operation mode of the present invention will be described. In accordance with the situation of the place where the crane is installed, the turning restriction range is set within the switch box 22 'of the detecting mechanism 21 by the positions of the turning position detecting switches 31, 31'. Set. Regarding the contraction length of the boom 8, the limit switch 28 is attached to the segments constituting the boom as described above, and the operation piece 29 is attached to the middle segment 8B for use.

When a normal crane operation is performed, a known operation can be performed without any problem regarding the expansion and contraction of the boom 8, the undulation, and the operation of the suspension cable 11.

When the swing operation is performed with the boom 8 in the extended state and the swing reaches the swing restriction range, for example, one of the previously set swing position detection switches 31 is operated by the operation piece 32, and the swing point A is detected. When the circuit A is cut off, the closed contact RA 'of the relay RA is opened, the contact KS "in the circuit C is opened by the operation of the keep relay KS, and the excitation of the auxiliary relay R2 is stopped. When the auxiliary relay contact R2 'in the relay circuit of the right-turn relay R3 of the boom opens, the relay
The excitation of R3 stops, and although not shown, the turning drive unit stops. Then, the driver knows that the boom 8 needs to be contracted, so that the driver presses the push button switch PB4 of the boom contraction operation circuit to excite the relay R6 and activates the boom extension / contraction drive unit (hydraulic cylinder) in the contraction direction. .

When the boom 8 is contracted to the set length by the contraction operation, the limit switch 28 attached to either the trunk or the tip of the boom 8 is operated by the operation piece 29 attached to the boom 8 to excite the relay R1 of the circuit A. Is cut off. As a result, the boom extending circuit is cut off, and the boom 8 cannot be extended.

Next, in the turning operation of the boom 8, the operation piece 32 is operated by returning to the turning point A to operate the limit switch 31 or the turning switch B.
When the vehicle passes the point, the keep relay KS is reset by the temporary stop of the relay R4 or the relay PB, the prohibition of the boom extension is released, and the normal operation becomes possible.

Therefore, within the range where the boom 8 is contracted and the extension is prohibited, there is no problem in the direction in which the length of the boom 8 is contracted. The boom can withstand lifting work in the contracted state. Also, when the turning direction is reversed, the operation of the boom left turning circuit key becomes the same as described above by the operation of the relay PB in the turning B point detection circuit A ', and as a result, the boom is set within the turning restriction range. If the contraction is not performed below the condition, the work cannot be performed, and if it moves out of the turning restriction range, the normal work becomes free.

It should be noted that a relay can be incorporated in the electric control mechanism so that the boom can be automatically contracted as needed.

When the turning restriction range is wide-angle and it is necessary to change the boom length in multiple steps, two more detection switches are arranged between the turning detection positions of point A and point B in the above embodiment. It is also possible to regulate the boom turning angle and the boom contraction length in multiple stages with these switches.

Effect of the Invention: As described above, in the present invention, when there is a construction crane within the working radius, such as a pre-built or another crane, which has a trouble in work, the turning restriction range is set. By doing so, the boom can always be shortened within the regulation range so that no obstacles occur, so that safety can be maintained without causing an accident due to crane operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a construction tower crane to which the present invention is attached, FIGS. 2 and 3 are diagrams showing an example of a turning restriction range detecting mechanism, and FIG. 4 is a diagram for setting a contraction length of a boom. FIG. 5 is a diagram showing a procedure for mounting the limit switch, and FIG. 5 is a circuit diagram showing an electric control mechanism. DESCRIPTION OF SYMBOLS 1 ... Tower crane for construction, 6 ... Turning table 8 ... Boom 8A, 8B, 8C ... Boom segment 20 ... Turning control device 21 ... Turning control range detecting mechanism 22 ... Screw limit switch 23 ... … Screw shaft, 25… Gear transmission mechanism 28… Limit switch for setting the contraction length of the boom 29, 32… Operation piece, 30… Electric control mechanism 31, 31 '… Switch for turning position detection R1, R2, R3, R4, R5, R6, RA, RB ... Relay R2 ', R3', R4 ', R5', R6 ', RA', RB '... Relay closed contact R1 ", R3", R4 ", KS ″… Relay open contact KS …… Keep relay PB1, PB2, PB3, PB4 …… Push button switch

Continuation of the front page (56) References JP-A-56-75393 (JP, A) JP-A-63-66099 (JP, A) JP-A-1-181696 (JP, A) , U)

Claims (1)

(57) [Claims] 1. A control mechanism for a construction tower crane having a boom having a telescopic function: at least two turning position detecting limit switches are provided in association with a turning drive unit, and the boom is provided from a tip to a trunk. A limit switch for setting the length of contraction of the boom is provided at an appropriate position of the segment; the turning operation is performed by operating the turning position detecting limit switches arranged at both outermost positions of the target regulating rotation angle among all the turning angles. Is temporarily stopped and the boom telescopic drive unit is operated to contract the boom to the set length, and the boom can be operated in the contracted state in the section to the next outermost turning position detection limit switch position, except for the restricted rotation angle section. An electrical control mechanism that regulates normal crane operation in the turning range of the construction clay; Of turning restricting device.