JP2844355B2 - Truck crane jack control device - Google Patents

Description

The present invention relates to a jack control device for a truck crane,
In particular, a jack crane control device for a truck crane in which a stretchable horizontal beam is provided at a center portion and a rear portion of a body frame of the truck crane, and jacks are respectively provided at an end of the horizontal beam and a front portion of the body frame. About.

(Prior Art) A conventional truck crane is provided with an extendable horizontal beam at a center portion and a rear portion of a body frame thereof, and a jack provided at an end of the horizontal beam and a front portion of the body frame, respectively. For example, there is a jack control device as shown in FIG.
No. 61-47734).

The outer shape of the truck crane is attached to a rear end jack 10 via a swing arm 9 at the rear end of the body frame 1.
Except for the fact that the present embodiment is not provided, it has substantially the same structure as that of FIGS. 4 (plan view) and FIG. 5 (side view) showing the outer shape of the embodiment of the present invention. With reference to FIGS. 4 and 5, it is assumed that the swing arm 9 and the rear end jack 10 are not provided at the rear end of the body frame 1.

This is the rear part of the body frame of truck crane A
A revolving unit 4 that revolves on a revolving table 3 of 1A is provided with an up / down cylinder 5a.
, And two pairs of left and right front and rear horizontal beams 7, 7,... Extendable in the left and right direction are provided at the center and rear of the body frame 1, and the horizontal beams 7, 7,. The left and right front and rear intermediate jacks 8, 8,... For stabilizing the vehicle body are provided at the ends, and the front end jack 11 is provided at the front portion 1B, which is weaker in bending and twisting strength than the rear portion 1A of the body frame 1. Things.

In addition, 13 is a direction switching valve, 14, 15, 17, and 18 are oil passages, 16 is a solenoid valve, 19 is a sequence valve, 20 is a check valve, 21 is a pump as a hydraulic pressure source, 23 is a tank, 27 is wiring, 28 is a switch.

And in this case, the rear part of the body frame 1
The front end jack 11 provided on the front portion 1B having a weaker bending and torsion strength than 1A, and the left, right, front and rear intermediate jacks 8,
In order to prevent excessive bending and torsion loads from being generated in the front portion 1B of the body frame 1 when the body frame 1 is supported by 8..., The hydraulic pressure of the front end jack 11 that supports the front portion 1B of the body frame 1 The pressure receiving area of the cylinder 11A is smaller than the pressure receiving area of the intermediate jacks 8, 8,... Provided at the ends of the horizontal beams 7, 7,. The relief valve 19 that opens by rising and the check valve 20 that allows oil to return to the tank 23 are connected to the front and rear intermediate jacks 8,8,.
.. Provided in parallel in the oil passage 17 on the high pressure side when reducing the front end jack 11 after the front and rear intermediate jacks 8, 8,.
When the hydraulic jack is extended, the front and rear intermediate jacks 8, 8,... Are delayed, the front end jack 11 supports the vehicle body front, and the front portion 1B of the body frame 1 is bent or twisted. When the jack is reduced from the lifting state of the vehicle body, the action of the relief valve 19
The front and rear intermediate jacks 8, 8,... Are reduced by the high pressure generated after the front end jack 11 has been reduced.

(Problems to be Solved by the Invention) However, in this case, the cylinder of the front end jack 11 is restricted in order to regulate the operation order of each jack.
Relief valve 19 that is opened using the hydraulic pressure generated at 11A 19
And it is necessary to provide a check valve 20 in parallel with it,
There has been a problem that the control circuit is correspondingly complicated.

The present invention has been made in view of such a problem in the conventional example,
At the center and the rear of the body frame, a horizontal beam that can expand and contract in the left-right direction of the body frame is provided, an intermediate jack is provided at an end of the horizontal beam, a hydraulic cylinder of the intermediate jack, and a front part of the body frame. The hydraulic cylinder of the front end jack provided in the above is connected to a hydraulic source via a directional switching valve, and the switching switch of the hydraulic oil supply / discharge valve of each of the hydraulic cylinders has an open switch at both ends to turn off the control circuit. Arranged in a required order on the single switch line, and the selector switch of each pressure oil supply / discharge valve can be sequentially selected by the select lever of the second select switch reciprocating along the switch line. By doing
A jack control device for a truck crane that can control the operation sequence of each jack so as not to complicate the jack control circuit and to prevent excessive bending or twisting at the front portion of the body frame. It is intended to provide.

(Means for Solving the Problems) In order to solve the above-described problems of the conventional example, the present invention is capable of extending and contracting in the left and right directions of the body frame at a center portion and a rear portion of the body frame. A horizontal beam provided with a jack is provided, and a hydraulic cylinder of the intermediate jack and a hydraulic cylinder of a front end jack provided at a front portion of the vehicle body frame are connected to a hydraulic source via a direction switching valve. Set the supply / discharge valve selector switch to
On the control panel of the jack control device, the switch is disposed in a required order on a single switch line having an open switch at each end for turning off the control circuit. A truck crane jack control device configured to be sequentially selectable by a select lever reciprocating along a single switch line, and wherein a changeover switch for a supply / discharge valve of a hydraulic cylinder of the front end outrigger is provided with the intermediate jack. The single cylinder switch line is disposed at the rear of the single switch line in the forward direction as a step of raising the vehicle body by the jack cylinder.

(Operation) Since the present invention has the above-described configuration, when the vehicle body frame is pushed up and supported by each of the jacks, the select lever of the second select switch provided on the control panel is moved. By sequentially operating the intermediate jack cylinder in the forward direction as a step of raising the vehicle body by the intermediate jack cylinder along the single switch line, first, the pressure oil supply / discharge valve of the intermediate jack cylinder is switched (opened). After supplying the pressurized oil to the intermediate cylinder and extending the jack cylinder to support the center and the rear of the body frame, especially the body frame having the swivel,
The front end jack is extended by supplying pressurized oil to the front end jack cylinder to support the front part of the vehicle body frame.

Further, when switching from a state in which the jack of the body frame is supported by the jack to the ground to a state in which it is supported by wheels, by operating the select lever of the second select switch in the opposite direction, the front end jack is first operated. After opening the pressure oil supply and discharge valve of the cylinder and discharging the pressure oil from the front end jack cylinder to the tank, the front end jack is reduced and separated from the ground, and pulled up near the front end of the vehicle body frame, 2 When the select lever of the select switch is further rotated in the same (reverse) direction, the pressure oil supply / discharge valve of the intermediate jack cylinder is opened by the changeover switch, the intermediate jack cylinder is reduced, and the vehicle body is moved by the front and rear intermediate jacks. The supporting state of the frame, especially the central part and the rear part thereof, is released, so that a large load applied to the vehicle body frame is reduced. In any case, the operation order of the intermediate jack and the front end jack is incorrect so that the intermediate jack is supported by the intermediate jack and the heavy load of the truck crane is not supported by only the front end of the body frame and the front end jack. Operate without.

Further, each selector switch of the hydraulic supply / discharge valve of the hydraulic cylinder of each jack is provided with a first and a second release switch for turning off the control circuit at both ends at appropriate positions on the control panel of the jack control device. The switches are arranged in a required order on a single switch line at appropriate intervals, and required operations are performed by selecting each changeover switch of a hydraulic supply / discharge valve of a hydraulic cylinder of each jack by a select lever of the second select switch. Later, the supply / discharge valve changeover switch of each of the jack cylinders locks the support or release of the support of the body frame by the jack cylinder or the like by selecting the first or second open switch for turning off the control circuit. .

(Embodiment) Hereinafter, first to fifth embodiments of the jack control device for a truck crane according to the present invention will be described with reference to FIGS. 1 to 9. Note that the same parts as those of the conventional example shown in FIG.

First Embodiment FIGS. 1 to 5 schematically show a first embodiment of the present invention. In the drawings, reference numeral 1 denotes a body frame of a truck crane A, and 1A denotes a rear portion of the body frame 1. The fourth
In the figure, the reference numeral indicating the central portion of the body frame 1 is omitted), 1B is the front portion of the body frame 1, and the bending and torsional strength of the front portion 1B of the body frame 1 is considerably smaller than that of the rear portion 1A. 2 is a cab provided above the front part 1B of the body frame 1, 3 is a turntable on the rear part 1A of the body frame, 4
Is a revolving body on the revolving base 3, and the revolving body 4 has a telescopic boom 5
Is pivotally mounted, and an up / down operation is performed by an up / down cylinder 5a.

Reference numeral 6 denotes a hook suspended by a rope hanging from a boom head at the top of the telescopic boom 5. Reference numerals 7, 7,...
The left, right, front, and rear horizontal beams provided so as to be expandable and contractible by 7A, 7A... Are provided at the ends of the front and rear horizontal beams 7, 7,. Left and right front and rear middle jacks with front and rear middle cylinders 8A, 8A
Is a swing arm provided at the rear end of the body frame 1 so as to be swingable and lockable, 10 is a rear end jack provided at the end of the swing arm 9 and vertically extended and contracted by a hydraulic cylinder 10A.
1 is provided on a front portion 1B of the body frame 1 and includes a hydraulic cylinder 1
1A front end jack which expands and contracts vertically, 13 is a directional control valve, 19 is a relief valve, 21 is a pump as a hydraulic source, 23
Are tanks. These structures are almost the same as those of the conventional example described above, except that a rear end jack 10 is provided at the rear end of the body frame 1 via a swing arm 9.

Reference numeral 31 denotes a control panel provided on the revolving superstructure 4 and other places suitable for crane operation. The control panel 31 includes a first select switch 32, a second select switch 33, an accelerator switch 39, a bi-rot lamp 40, and the like. .

The first select switch 32 includes left and right beam cylinders 7A, 7A,... For expanding and contracting the left, right, front and rear horizontal beams 7, 7,.
· Supply and discharge valves IB, IIB, IIIB, IVB with the left and right front and rear intermediate jacks 8, 8 · · · telescopic cylinders 8A, 8A · · · provided at the end of
Switches I, II, III, IV for selecting any of
And a centralized switch V of the centralized supply / discharge switching valve VB of all the cylinders.

The second select switch 33 selects a horizontal beam switch H for selecting a switching valve 7B (not shown) of the telescopic cylinder 7A of the horizontal beam 7 and a supply / discharge valve 8B (not shown) for the telescopic cylinder 8A of the intermediate jack 8. An intermediate jack switch V, a rear jack switch R for selecting the supply / discharge valve 10B of the hydraulic cylinder 10A of the rear jack 10, and a front jack switch F for selecting the supply / discharge valve 11B of the hydraulic cylinder 11A of the front jack 11. On the switch line 34A in a semicircular arc shape having an open switch position for turning off the control circuit at both ends, the switch line 34A is disposed in the required order described above at appropriate intervals, and the left and right ends (first A single select lever 34 reciprocating along the switch line 34A between the first open switch OFF and the second open switch OFF for turning off the control circuit disposed in FIG. Be composed. In addition, 25 is a filter, 36 and 37 are oil passages, and 38 is a double check valve.

(Operation of the first embodiment) (Lift of body frame) Up and down and / or expansion and contraction of a telescopic boom 5 provided on a revolving unit 4 on a revolving base 3 on a central portion and a rear portion 1A of the body frame 1, winding of a wire, Prior to the cargo handling operation by rewinding or the like, all or any of I to IV of the first select switch 32 is selected (however, in the case of all the selections, selection by the central changeover switch V is also possible), and then the second select is performed. When the select lever 34 of the switch 33 is moved from the first open switch selecting position OFF for turning off the control circuit to the horizontal beam switch selecting position H, the pressure oil of the pump 21 passes through the direction switching valve 13 and the horizontal beam 7, 7. The telescopic cylinders 7A, 7A, and the pressure oil supply / discharge switching valves IB, IIB, IIIB, IVB, VB of 7A. Therefore, any or all of the horizontal beam cylinders 7A, 7A,... Are extended to extend the outrigger horizontal beams 7, 7,.

Next, the select lever 34 of the second select switch 33
Is turned to the intermediate jack switch V position for selecting the intermediate jack switch, and the right and left front and rear outriggers 8, 8,... Jack cylinders 8A, 8A... Switching valves IB, IIB, IIIB, I
Select any or all of I, II, III, and IV of the VB changeover switch.
The hydraulic cylinders 8A, 8A,... Of the left and right front and rear middle jacks 8, 8,.
The ground is grounded, and the central portion and the rear portion 1A of the body frame 1 (the portion on which the upper swivel 3 is mounted) are supported by the intermediate jacks 8, 8,... Of the outriggers.

From this state, when the select lever 34 of the second select switch 33 is turned to the rear end jack switch position R for selecting the hydraulic oil switching valve 10B to the jack cylinder 10A of the rear end jack 10, the hydraulic cylinder 10A of the rear end jack 10 is turned. The pressurized oil supply / discharge valve 10B is opened, the jack cylinder 10A is extended by the pressurized oil, the rear end jack 10 is grounded, and the rear end jack 10
With this, the rear end of the body frame 1 is additionally supported.

Thereafter, when the select lever 34 of the second select switch 33 is turned to the switch selection position F of the front end jack 11, the supply / discharge valve 11B of the jack cylinder 11A of the front end jack 11 is turned on.
Is opened and the jack cylinder of the front end jack 11 is
The front end jack 11 is extended and the front end jack 11 comes into contact with the ground, so that the front portion 1B of the vehicle body frame 1 is additionally supported.

Next, the select lever 34 of the second select switch 33
To turn off the control circuit.
Turning to the right side of FIG. 1, the excitation of the pressure oil switching valves IB, IIB, IIIB, IVB by the respective changeover switches is released, and the neutral state of the pressure oil supply / discharge valves 10B, 11B is secured. The respective hydraulic cylinders are locked in their respective operating positions,
The body frame 1 is stably supported on the ground by the jacks 8, 8,.

(Descent of the body frame) When the jacks 8, 8,..., 10, 11 and the like are reduced and the body frame 1 is lowered to be supported by wheels, the direction switching valve 13 is switched to the pressure oil supply / discharge position. On the other hand, the second
When the select lever 34 of the select switch 33 is returned from the second opening switch selection position OFF (right side in FIG. 1) for turning off the control circuit to the selection position F of the front end jack 11 switch, the switching valve 11B opens and the front end The pressure oil of the jack cylinder 11A is discharged to the tank 23 via the switching valve 11B, the oil passage 36, the double check valve 38, etc., the front end jack cylinder 11A contracts, and the front end jack 11 separates from the ground.

Next, when the select lever 34 is turned to the selected position R of the rear end jack 10 switch, the supply / discharge valve 10B is opened, and the pressure oil of the hydraulic cylinder 10A of the rear end jack 10 is supplied to the supply / discharge valve 10B, piping 3
6. Discharged to the tank 23 via the double check valve 38, the relief valve 19, etc., the rear end jack cylinder 10A contracts and separates from the ground.

Next, the select lever 34 is set to the position for selecting the intermediate jack switch V of the front and rear intermediate jacks 8, 8,.
When any or all of IV are selected (when all of them are selected, selection by the centralized switch V is also possible), any or all of the left and right front and rear intermediate jack cylinders 8A, 8A,. Any or all of the supply / discharge valves IB, IIB, IIIB, IVB, or the central supply / discharge valve VB, oil path 36, double check valve 38, relief valve 19, etc. , 8,... Are reduced, separated from the ground, the body frame 1 is lowered, and the body frame 1 is supported by wheels.

When the select lever 34 of the second select switch 33 is set to the horizontal beam 7, 7,... Select position H, while selecting any or all of the left, right, front and rear changeover switches I to IV of the first select switch 32 (select all) In this case, the centralized changeover switch V can be selected), and any or all of the supply / discharge valves IB and IVB or the central supply / discharge valve VB is connected to the horizontal cylinders 7A, 7A,. It is discharged to the tank 23 through the check valve 38 and the like, and the horizontal beams
・ ・ Reduce the middle jacks 8, 8 ・
It is stored on the body frame 1 side (within the vehicle width).

Next, the select lever 34 of the second select switch 33
To turn off the control circuit.
(Left side in FIG. 1), and the horizontal beams 7, 7,.
Middle jacks at the end, front and rear 8, 8, ..., rear end jacks
10. Set the front end jack 11 and the like to the lock position. Note that the first open switch selection position OFF located at the left end (FIG. 1) of the single switch line 34A is a state in which the operation of the cylinders and the like of the apparatus at the next operation, that is, a transition to the extension operation thereof, is possible. To

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. 6, which schematically shows a second select switch section which forms a main part and is provided on a control panel thereof. . The remaining structure and operation of the second embodiment of the present invention are almost the same as those of the first embodiment.

In FIG. 6, reference numeral 41 denotes a control panel according to a second embodiment of the present invention. The control panel 41 has a first open switch selection position OFF (left side in FIG. 6) for turning off the control circuit, a horizontal beam SW selection. Position H, middle jack SW selection position V, rear end jack SW selection position R, front end jack SW
A selection position F, a second open switch selection position OFF for turning off the control circuit (the right side OFF in the figure) is aligned with a single linear switch line 44A extending in the left-right direction, and has a required interval with a required interval. They are provided in order (similar to the first embodiment).

By sequentially moving the select lever 44 of the second select switch 43 rightward (forward) or leftward (reverse) along the single switch line 44A, the switch positions OFF, H, V, R , F, or OFF,
The front and rear horizontal beams 7, 7,..., Front and rear intermediate jacks 8, 8,..., Rear end jack 10, front end jack 11, etc. shown in FIG. 4 (first embodiment) are the same as those of the first embodiment. Control is performed in substantially the same order.

(Third to Fifth Embodiments) Next, the third to fifth embodiments of the present invention will be described with reference to the control panels 51, 61, and 71 provided with the second select switches 53, 63, and 73, which are essential parts thereof. The seventh of the schematic plan view of the main part
This will be described with reference to FIGS. The third embodiment of the present invention
The remaining structure and operation of the fifth to fifth embodiments are almost the same as those of the first and second embodiments.

7 to 9, 51 (FIG. 7), 61 (FIG. 8)
FIG. 7 and FIG. 9 (FIG. 9) are control panels according to the third to fifth embodiments of the present invention.
51, 61, and 71 include second select switches 53 (FIG. 7) and 63.
(FIG. 8) and 73 (FIG. 9) are provided, respectively.

Select levers of the second select switches 53 (FIG. 7), 63 (FIG. 8) and 73 (FIG. 9) of the third to fifth embodiments.
Reference numerals 54 (FIG. 7), 64 (FIG. 8), and 74 (FIG. 9) denote a first open SW selection position OFF (the left side in FIGS. 7 and 8, the right side in FIG. 9) for turning off the control circuit, and the horizontal beam. SW selection position (H),
Middle jack SW selection position (V), rear end jack SW selection position (R), front end jack SW selection position (F), second open SW selection position OFF for turning off the control circuit (right side in FIGS. 7 and 8, 9 (left side) is a single switch line 54A
(Downward U-shaped, rightward, FIG. 7), 64A (downward U-shaped, rightward, FIG. 8), and 74A (upward U-shaped, leftward, FIG. 9) And second select switches 53 and 6 respectively.
3, 73 select levers 54, 64, 74, the single downward U-shaped switch line 54A, the same single downward U-shaped switch line 64A, the same single downward U-shaped switch line 74A
Along each of the downward U-shaped (upward, right, downward positive direction, and upward, left, downward reverse direction), downward U-shaped (up,
Reciprocate in the right, downward positive direction and upward, left, downward downward direction) or upward U-shaped (downward, left, upward upward direction and downward, right, upward reverse direction) By doing so, the first and second
The jack control of the truck crane is performed in substantially the same manner as in the embodiment.

(Modification) A single switch line of the second select switch according to the present invention is not shown, but extends along the control panel (see reference numeral 31 in FIG. 1 of the first embodiment) in the vertical direction. In addition to being able to be disposed in a straight line extending upward, obliquely upwardly or obliquely upward, as long as a sufficient space can be secured in the vertical direction with respect to the control panel 41 surface in FIG. 6 (see the second embodiment), for example. The first switch line 44A of the second select switch 43 is disposed so as to extend in the direction perpendicular to the control panel 41, and the select lever is moved up and down along the switch line (not shown). Also in this case, except that the operation direction of the select lever is perpendicular to the plane of the paper, the horizontal beam and the center beam are substantially the same as in the above-described embodiments. Jack, rear jacks, the control such as the front jacks allows the substantially same manner.

(Effects of the Invention) The present invention has the above-described configuration and operates, and the following effects can be obtained.

(1) After extending all or part of the horizontal beam provided in the intermediate portion of the vehicle body frame to a required position by the first select switch provided on the control panel, the select lever of the second select switch is moved to the jack. First, the horizontal beam cylinder is extended by sequentially operating the changeover switches arranged in a predetermined order on a single switch line by sequentially operating the cylinder in the forward direction as a lifting operation process of the vehicle body by the cylinder. After extending the horizontal beam, the extension of the jack cylinder of the intermediate jack provided at the end of the horizontal beam is completed, the body jack is supported by the intermediate jack, and the select lever is moved in the same forward direction. To extend the front end jack by extending the front end jack cylinder to support the front end of the body frame. In addition, by operating the select lever in the opposite direction to sequentially select the switches in the opposite direction, first, the front end jack cylinder is reduced to reduce the front end jack, and then the horizontal beam end is reduced. The jack cylinder of the part is reduced, and there is no danger that a state in which the front part of the body frame is supported by only the front end jack is caused. No risk of twisting.

(2) The extension operation of the front end jack is performed by selecting the front end jack switch at the end of the movement of the select lever, which moves along the single switch line of the second select switch, in the forward direction as the ascending direction of the vehicle body frame. Further, after the front end jack is contracted by selecting the front end jack switch in the initial stage of the reverse operation of the select lever, the intermediate jack switch is selected, the intermediate jack cylinder is contracted, and the intermediate jack is contracted. Therefore, there is no possibility that an error occurs in the operation order of each jack.

(3) After the supply of the pressure oil to the front jack cylinder is completed, and after the discharge of the pressure oil from the front jack cylinder is completed, the pressure oil is discharged from the intermediate jack cylinder. As a result, no excessive load is applied to the front portion of the vehicle body frame, and there is no possibility that bending or torsion may occur at the front portion of the vehicle body frame.

(4) While the extension operation of the front jack is performed after the extension of the other jack or horizontal beam is completed, the contraction operation of the other jack or the horizontal beam is performed after the contraction of the front jack is completed. The safe operability of the circuit is ensured, and the control circuit can be configured more simply than conventional similar devices.

(5) As long as a sufficient space can be secured around the installation portion of the control panel, the shape of a single switch line for reciprocating the switch lever of the second select switch can be freely selected. The degree of freedom is improved.

(6) At both ends, the select lever of the second select switch reciprocating along the single switch line provided with the first and second open switches for turning off the control circuit is moved in the forward direction or By selectively operating up to a predetermined position in one of the opposite directions, the operation state or the operation release state of each jack cylinder of the truck crane is ensured.

[Brief description of the drawings]

FIGS. 1 to 9 show an embodiment of a jack control device for a truck crane according to the present invention. FIG. 1 is a schematic explanatory view of a control panel of the first embodiment, and FIGS. FIG. 4 is an explanatory view of the hydraulic circuit and an explanatory view of the electric control circuit, FIG. 4 is a side view of the truck crane, FIG. 5 is a plan view of essential parts of the truck crane, and FIGS. FIG. 10 is a schematic explanatory view showing a second select switch section provided in a control panel as a main part of the second to fifth embodiments of the present invention. FIG. 10 is an explanatory view of a hydraulic circuit of a conventional jack crane control device for a truck crane. is there. (Explanation of reference numerals) A: Truck crane 1: Body frame 1A: Front part of body frame 1B ... Rear part of body frame 2 ... Operator cab 3 ... Revolving base 4 ... Revolving body 5 ... Telescopic boom 5a: Up / down cylinder 6: Hook 7, 7: Horizontal beam of outrigger 7A, 7A: Beam cylinder 8, 8: Intermediate jack 8A, 8A: Intermediate jack cylinder 9: Swing arm 10: Rear End jack 10A …… Rear end jack cylinder 11 …… Front end jack 11A …… Front end jack cylinder 14, 15 …… Oil passage 16 …… Electromagnetic valve 17, 18 …… Oil passage 19 …… Sequence valve 20 …… Check valve 21 … Pump (hydraulic power source) 23… Tank 27… Wiring 28… Switch 31, 41, 51… Control panel 32… First select switch 33, 43, 53… Second select switch 34, 44, 54 ... Select lever 34A, 44A, 54A ... Switch line 39 ... Accelerator switch 40 ... Pilot lamp 61,71 ... Control panel 63,73 ... Second select switch 64,74 ... Select lever 64A, 74A ... Switch line I ... Right front switch II ... Front left switch III Right rear switch IV Left rear switch V Centralized switch H Horizontal beam switch V Middle jack switch R Rear jack switch F Front jack switch OFF ... First and second release switches

Claims (5)

(57) [Claims] 1. A horizontal beam which is expandable and contractible in the left-right direction of the vehicle body frame and has an intermediate jack at an end portion is provided at a center portion and a rear portion of the vehicle body frame, and a hydraulic cylinder of the intermediate jack is provided in front of the vehicle body frame. The hydraulic cylinder of the front end jack provided in the section is connected to a hydraulic source via a directional switching valve, and the switching switches of the supply and discharge valves of each of the hydraulic cylinders are respectively connected to both ends on the control panel of the jack control device. Arranged in a required order on a single switch line with an open switch that turns off the control circuit,
A jack crane control device for a truck crane, wherein a changeover switch of each pressure oil supply / discharge valve is sequentially selectable by a select lever reciprocating along the single switch line. 2. The switch for switching the supply / discharge valve of the hydraulic cylinder of the front end outrigger is moved from the switch for switching the supply / discharge valve of the hydraulic cylinder of the intermediate jack to the elevation of the vehicle body by the jack cylinder in the single switch line. The jack control device for a truck crane according to claim 1, wherein the jack control device is disposed at a rear position in a forward direction as an operation step. 3. A center beam and a rear portion of the body frame are provided with left and right and front and rear horizontal beams which are expandable and contractible in the left and right direction of the body frame and have intermediate jacks at ends thereof, and a hydraulic cylinder of each of the intermediate jacks, The hydraulic cylinder of the front end jack provided at the front part of the body frame is connected to a hydraulic source via a direction switching valve, and each changeover switch of the hydraulic supply / discharge valve of the hydraulic cylinder of each jack is connected to the jack control device. At appropriate positions on the control panel, the control circuits are arranged at required ends on a single switch line having first and second open switches at appropriate intervals and in a required order. Switch of the hydraulic oil supply / discharge valve to the hydraulic cylinder can be sequentially selected by the select lever of the second select switch that reciprocates along the single switch line. Jack control truck crane, characterized in that it is arranged. 4. A supply / discharge valve changeover switch for the horizontal beam hydraulic cylinder, a supply / discharge valve changeover switch for the intermediate jack cylinder, a supply / discharge valve changeover switch for the rear end jack cylinder, and a supply / discharge valve changeover switch for the front end jack cylinder. On the control panel, on a single switch line having first and second open switches for turning off the control circuit at both ends, arranged in the order of the changeover switches at appropriate intervals. The jack control device for a truck crane according to claim (3). 5. A single switch line of the control panel is selected by a select lever of a second select switch at a forward most position and a last position in a forward direction as a step of raising the body frame by the jack cylinder, The jack control device for a truck crane according to claim 4, wherein a first opening switch and a second opening switch for turning off the control circuit are provided.