DE2558014A1 - CONTROL FOR THE DOZER BLADE OF A DOZER - Google Patents

Description

25580H

COM 6

Kabushiki Kaisha Komatsu Seisakusho

Control for the dozer blade of a grading machine

The invention relates to a control for the automatic and manual actuation of the blade of a planer machine _o

There are essentially two types of control and control devices for the working movements of the dozer blades known from bulldozers and bulldozers. One of the known devices uses a laser beam, which is sent out by the machine to create a reference plane «The machine receives the beam and scans it so that the dozer blade can be held at a certain height in relation to the reference plane " The other type of known device uses an angle measuring device attached to the blade lift arm is for the purpose of keeping the dozer blade at a constant angle of inclination »

Known devices of the former type have the disadvantage that they are complicated and expensive to manufacture

ORIGINAL INSPECTED

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and their operation is affected by pollution, while the known devices of the second type are affected by the vibrations of the leveler itself in its operation.

The aim of the present invention is therefore a control for the dozer blade of a grading machine that is free from is the aforementioned disadvantages of known devices, and essentially meet the following requirements will: The control should be suitable for automatic-automatic and manual operation, even with automatic mode of operation the manual operation should have priority so that you can always press the manual control elements in the automatic functional sequence can intervene »The aim of this requirement is to provide the necessary To limit manual interventions to a minimum in order not to tire the operating personnel an automatic limit for the downward movement of the blade can be achieved that leveling work easily and can be carried out safely even by inexperienced personnel.

This aim is achieved according to the invention by a control for a cylinder which is provided with a working cylinder for raising and lowering Reached dozer blade, which is characterized by an arrangement which consists of the following elements:

- A solenoid valve to control the working cylinder,

- Switching means for switching between manual and automatic actuation of the dozer blade,

- a safety relay connected to these control means, which can only be energized when these switching means are in the position for manual operation ,

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- A priority relay for manual operation, which is used to receive a signal from the safety relay

, is educated,

- A load limiting relay, which can be excited by a signal from a load acceptance measuring circuit, wherein it forwards a signal from the priority relay to one of the solenoid coils of the solenoid valve, as well as from

- further switching means, by separating them in connection with the actuation of a manual switching lever the circuit for automatic actuation in the priority relay is interrupted.

Further features of the invention emerge from the ensuing Description of several exemplary embodiments shown in the accompanying drawings

Show it

Hg ₀ 1 a hydraulic circuit diagram of a first embodiment of the invention;

Mg «2 an electrical circuit that, according to the invention intended for use together with the hydraulic circuit according to FIG. 1;

Mg »3 the hydraulic circuit of a second embodiment of the invention;

4 shows the hydraulic circuit of a third embodiment of the invention;

Fig. 5 shows an electrical circuit according to the invention for use with the hydraulic circuit according to FIG Mg. 4;

! ig. 6 shows the hydraulic circuit of a fourth embodiment of the invention.

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The in-Fig. 1 illustrated hydraulic circuit of a control according to the invention consists essentially of a working cylinder 60 for the up and down movement of the dozer blade, a working cylinder 61 for the inclination of the dozer blade, a solenoid valve 3 to control the vertical movement of the dozer blade, a solenoid valve 6 for switching to free Mobility of the dozer blade and a solenoid valve 4 for controlling the inclination of the dozer blade _o As a result of a separation of the circuits for the control pressure medium and the working pressure medium, a control cylinder 35 is provided between the solenoid valve and the associated working cylinder, which in turn actuates a control valve 1, which directly affects the action of the working pressure medium influenced for the working cylinder 60 In a similar way, the solenoid valve 4 controls a control cylinder 28, which in turn actuates a control valve 2 which supplies the working pressure medium for the working cylinder 61 b einfluences ₀

The control valve 1 for the vertical movement of the dozer blade has an input 1a, which is via a pipeline 9 is connected to a pump 10 for the working pressure fluid. A secondary line 62 branches off from the line 9 which is connected to an input 1b. A pipeline 64 is also connected to the inlet 1b, in which a valve 14 is located «The line 9 contains an overflow valve 15o The dozer blade control valve 1 has also via two connections 1c and 1d, which are connected via pipes 16 and 17 to the end on the piston rod side or are connected to the head end of the working cylinder 60 for the vertical movement of the dozer blade Another connection 1e of the blade control valve is via a pipe 18 to an input 2a of the Control valve 2 for tilting the dozer blade connected »From the line 18 branches off a secondary line 19

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which is connected to a further input 2b of the control valve 2. The secondary line 19 contains a Y-valve 20. The control valve 2 for the inclined position of the dozer blade also has a connection 2o, from which a line 21 led to a container 22. The line 21 contains a filter 23. Furthermore, the control valve 2 for the inclined position of the Shield still two connections 2d and 2e, which are connected via pipes 24 and 25 with the piston rod-side end or the head end of the working cylinder 61 for the inclined position of the blade two lines 26 and 27 respectively, the connections 4a and 4b of a solenoid valve 4 are connected. The solenoid valve 4 also has an inlet 4c which is connected via a line 29 to a pump 30 for the pressure medium for the control circuit. The line 29 contains a filter 31. From a fourth connection 4d on the solenoid valve 4, a line leads back to a container 86 for the control pressure medium, _etc.

Similarly Y / else the Yertikalbewegung, has the solenoid valve 3 for the control of the dozing blade d _o h _o for its lifting and lowering, one input 3a, which is also connected to the pump 30 via a "line 32, and a terminal 3b, from which a line led back to the container 86. The solenoid valve 3 has two further connections 3c and 3d, which are connected via lines 33 and 34 to the head end 35a and the piston rod end 35b of a chamber of the control cylinder 35 for raising and lowering the blade are.

The solenoid valve 6 for the changeover to free mobility of the dozer blade has an input 6a and a connection 6b, of which the former via a line 36 to the pump 30 is connected and the latter has a return

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line to the container 86 has _o The solenoid valve 6 has two further connections 6c and 6d, which are connected via lines 37 and 38 to the head end 35c and the piston rod end 35d of a further chamber of the control cylinder 35 for the vertical movement of the blade. This control cylinder 35 contains two piston rods 39a and 39b, of which the former is attached to a spring which is movably attached to the control valve 1 for the vertical movement of the blade, while the latter is anchored in a fixed point on the machine _{or the like}

The already mentioned solenoid valve 3 contains a solenoid 40 for triggering the downward movement of the dozer blade and a solenoid 41 for triggering its upward movement s movement »The solenoid valve 4 also has a solenoid coil 65 or 66 on each side Controlling the free mobility of the dozer blade, however, has only one magnetic coil 44ο Ji'in connection of each aer Magnet coils 40,41,65,66 and 44 is connected to a voltage source 42 »

Reference numeral 67 in Fig. 2 denotes a control switch for manual operation, which has a switch 47> a switch 48 for the upward movement of the dozer blade, a switch 49 for its downward movement, a switch 50 for the free movement of the dozer blade, a switch 51, a switch 52 for tilting of the dozer blade to the left and a switch 53 for the inclination to the right, of which the Sehalter 48, 49 and 50 are each coupled or locked to switch 47 and switches 52 and 53 to switch 51 o One contact of each of the switches 47, 48, 49, 50, 53 and 52 is via a main switch 46 with the voltage source 42 connected.

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The second terminal of the solenoid coil 4-0 of the solenoid valve is 3 for the vertical movement of the scraper blade is connected to the switch 49 for the downward movement of the shield, while the second terminal of the magnet coil 41 is connected to the upward movement of the switch 48 for the upward movement _o The second connection of the solenoid 44 of the solenoid valve 6 for the free mobility of the dozer blade is on the switch 50 for controlling the free mobility _o Furthermore, the solenoids 65 and 66 of the solenoid valve 6 stand for the inclined position of the dozer blade with the switch 52 for the left inclined position or the switch 53 for the right inclination in connection ,, The second connection of the solenoid 41 for the upward movement of the blade is also via a limit switch 68 for limiting the upward movement with a contact 7a in contact group B- a manual override relay 7j and with a Contact 8c in the contact group pe C. a load limit relay 8 connected

Furthermore, the second connection of the solenoid 40 for the downward movement of the dozer blade is also connected to a limit switch 69 for limiting the downward movement Contact 8a in contact group 0., of the load limit relay 8 connected »The contact 5d of a safety relay 5 as well as the contact 7'd of the manual override relay 7 are connected to the voltage source 42 to which a Overload indicator lamp 43 also the contact 8'b of the contact group Cp of the load limiting relay 8 is hanging.

A contact 5c of the contact group A _{1 of} the safety relay 5 is connected via a Dio.de 12 and an indicator lamp 54 for automatic operation with the voltage source 42 ^ while a contact 5 ^f c of the contact group Ap of the safety relay 5 via a diode 13 and then also via the indicator lamp 54 for automatic operation on the voltage

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source 42 is _o

Furthermore, the same contacts 5c of contact group A ₁ and 5'c of contact group A _? of the safety relay 5 via the diodes 12 or 13 still connected to a contact 8'c of the contact group Cp of the load limiting relay 8. The contact 5c of the contact group A .. of the relay 5 'is also attached to the contact tongue 7'b of the contact group Bp of the manual mode priority relay 7> while the contact 5'c of the contact group Ap of the relay 5 is also connected to the contact tongue 7b of the contact group B- of the relay 7.

The relay coil 8P of the load limiting relay 8 is connected to a load-bearing measuring circuit 11. Any type of load-bearing measuring arrangement can be used be used if it only emits a suitable electrical signal through which the Relay coil 8P is always excited when the load on the dozer blade exceeds a certain value,

Reference numeral 45 in FIG. 2 denotes a selector switch for changing from automatic to manual operation and vice versa. The selector switch 45 has a movable contact 45a which is connected to the voltage source 42 via the main switch 46 automatic downward movement of the dozer blade, which is connected to the contact tongue 5b of the contact group Α .. of the safety relay 5, as well as a contact 45c for the automatic upward movement of the dozer blade, which is on the contact tongue 5'b of the contact group Ap of the safety relay 5 _o Finally contains the Selector switch 45 also has a contact 45d for manual operation, which is connected to the contact 5 ″ d of the relay 5. The contact tongue 5 ″ b of the contact group A of the safety relay 5 is connected to the voltage source 42. In addition, there is still a connection between the switch 51 and the contact 7d of the contact group B- des

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Manual operation priority relay 7 °

The mode of operation of the control according to the invention is explained below.

When the main switch 46 is engaged, the contact tongues 5b, 5'b and 5 ^ff b are moved to the right and the respective switching contacts are closed, but only when the selector switch 45 is set to manual mode (contact 45a to contact 45d) _o The contact tongues as well 7b and 7'b of the manual mode priority relay 7 are moved to the left and kept closed »

Then when the contact 45b for automatic downward movement is brought into Einsehaltstteilung, a signal is passed through the contact group A-, the contact group Ά * of the relay 7, the contact group CL of the relay 8 and the limit switch 69 for limiting the downward movement to the solenoid 40 , since the relay 5 remained in the self-holding position via the contact group A, but this switch position only exists if the load _{absorption of the dozer blade is small o} If the load absorption exceeds a certain threshold, the relay coil 8P of the load limiting relay 8 is energized and thereby the contact tongue 8b of the contact group C, placed on the üontakt 8c, so that a signal via the limit switch 68 for the limitation of the upward movement to the magnetic coil 41 is passed on.

When the solenoid 40 is used for the downward movement of the dozer blade Receives voltage, the valve passages D in the solenoid valve 3 for the vertical movement of the dozer blade moved for the downward movement between the valve ports, whereby the control cylinder 35 is actuated. This in turn moves the control valve 1 for the vertical

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Movement of the dozer blade into the lowering position E, whereby the working cylinder 60 is acted upon in such a way that it lowers the dozer blade _{or the like}

If, on the other hand, the solenoid 41 for the upward movement of the dozer blade receives voltage, the solenoid valve 3 is in the lifting position]? moved, whereby the control cylinder 35 is operated in the opposite direction so that it the control valve 1 for the Tertikaibewigung of the dozer blade in the lifting position G-moved, whereby the working cylinder 60 is acted upon so that it lowers the dozer blade.

If the threshold value for the load acceptance is undershot again during the upward movement, the load limiting relay drops 8 again and the magnetic coil 40 for the downward movement is activated again. This cycle repeats yourself ο

If the dozer blade exceeds a previously set lower or upper limit during its vertical movement for the movement play, either the limit switch 69 for limiting the upward movement or the limit switch 68 opened for the limitation of the downward movement, whereby the solenoid valve 3 for the vertical movement in its H is switched to neutral position and the movement of the dozer blade is stopped o

The manual operation of the control is explained below. the switch 47 is opened and the switch 48 for the upward movement is closed »This causes the solenoid 41 energized for the upward movement and the solenoid valve 3 for the vertical movement in the lift position]? emotional, whereby the control cylinder 35 for the vertical movement of the

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The leveling blade is actuated and the control valve 1 is also moved into its lifting position I ¹ , in which it releases the path for the pressure medium to the working cylinder 60, the piston of which is displaced so that the leveling blade is raised. If, on the other hand, the dozer blade is to be lowered, switch 47 is also opened, but switch 49 is closed and switch 50 is kept open for the free movement of the dozer blade comes into action. This brings the control valve 1 for the vertical movement into lowering position E, whereby the piston in the working cylinder 60 is moved so that it lowers the dozer blade ο

It is desirable to make the dozer blade Irei movable the switch 47 is opened, and the switch 49 for the downward movement of the shield and the switch 50 for free movement closed by this switch position the solenoid valve 3 is moved to its lowering position D for the vertical movement and the solenoid valve 6 for the free movement of the dozer blade controlled so that the control cylinder 35 for the vertical movement comes into action. This moves the control valve 1 for vertical movement into position I for free mobility, in which Pail the piston in the working cylinder 60 is for the vertical movement of the blade due to an overflow connection Can move freely to and fro between the two sides of the piston when the dozer blade is exposed to external forces is moved,

ooll the dozer blade to be tilted to the right, the switch 51 is opened and the switch 53 is closed. This makes the solenoid valve 4 for the inclined position of the dozer blade to the right swivel position J

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brought so that the control cylinder 28 is controlled accordingly willo This moves the control valve 2 for the Inclination of the jrlanierschildes in its right pivot position K, so that the working cylinder 61 comes into action for the inclination and the dozer blade after swiveled right

If, on the other hand, the dozer blade is to be tilted to the left, the switch 51 is opened and the switch 52 closed. This switch position makes the solenoid valve 4 for the inclined position of the dozer blade moved into its Linkssohwenkstellung L, so that the control cylinder 28 is operated in such a way that he the Control valve 2 also in its left pivot position M moved, and the working cylinder 61 for the inclination pivoted the blade to the left

If either the switch 47 or the switch 51 is opened during manual operation, the coil of the manual operation priority relay 7 is de-energized, whereby the contact tongues 7b and 7'b move to the right and disconnect the circuit for the automatic operation, so that the automatic operation is interrupted _o

The Fig «, 3 shows another embodiment of the invention Steering." In this embodiment, the input is 3a of the solenoid valve 3 for the vertical movement of the blade via a pipe 70 with a connection 71a of a flow divider 71.) The connection 3b of the Solenoid valve 3 is connected via a pipe 72 to the inlet 6a of the solenoid valve 6 for free mobility of the dozer blade in connection. A line 77 also leads from connection 3b to a tank 22 for the control pressure medium The connections 3c and 3d of the solenoid valve 3 are finally via lines 73 and 74 with the piston rod side End or »the head end of the working cylinder

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The connection 6b of the solenoid valve 6 is connected to the connection 3a of the solenoid valve 3 and lines 75 and 76 also lead from the connections 6c and 6d of the solenoid valve 6 to the head end or the piston rod end of the working cylinder 60 _O

The connection 4a of the solenoid valve 4 for the sawing position of the dozer blade likewise opens into the line 77, which goes to the tank 22. The line 77 is provided with a filter 78. The connection 4b of the solenoid valve 4 is connected via a line 59 to a further connection 71b of the flow divider 71, while from the connections 4o and 4d of the solenoid valve 4 lines 80 and 81 to the piston rod end or _o lead to the head end of the working cylinder 61 for the sawing position of the dozer blade "

The aforementioned flow divider 71 also has an inlet 71c, which is connected to a pump 83 via a line 82. Line 82 includes a valve 84 and an overflow valve 85 ο

The electrical circuit of this second embodiment corresponds to that of the first,

So when the blade is to be raised, the switch 47 is opened and the switch 48 for the upward movement closed. This energizes the solenoid 41 to move upward so that it operates the solenoid valve 3 adjusted for the vertical movement in the lifting position P, what ultimately the working cylinder 60 accordingly is controlled and raised the dozer blade

If, on the other hand, the dozer blade is to be lowered, switch 47 is also opened, but switch 49 for

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the downward movement closed, with the switch 50 remaining open for the free movement of the dozer blade, By this switch position, the solenoid valve 3 is brought into its lowering position D, which ultimately the Working cylinder 60 is controlled so that it lowered the dozer blade

If free movement of the blade is desired, the switch 47 is opened and the switch 49 for the Downward movement as well as the switch 50 for the free movement of the dozer blade closed, This is the Solenoid valve 3 brought for the vertical movement in lowering position D and at the same time also the solenoid valve 6 for the free movement of the dozer blade adjusted so that the piston rod is within the working cylinder .60 can move freely back and forth in the cylinder due to external forces acting on the dozer blade.

If the dozer blade is to be tilted to the right, switch 51 is opened and switch 53 is closed. As a result, the solenoid valve 4 is moved into its ßechtsschwenkposition J for the inclined position of the dozer blade, whereby the working cylinder 61 for the inclined position is actuated in such a way that it swivels the dozer blade to the right »

If, however, it is necessary to tilt the blade to the left, the switch 51 is opened and the Switch 52 closed »This moves the solenoid valve 4 for tilting the dozer blade into its left swiveling position I moves, whereby the working cylinder 61 for the inclined position is operated so that it Dozer blade swivels to the left.

In Fig. 4 the hydraulic circuit is a third one . Embodiment of the invention reproduced ,, Daa control valve 1 for the vertical movement of the dozer blade is used to determine the direction of flow of the flow coming from the f-umpe 10

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Working pressure fluid between the head end and the piston rod end of the working cylinder 60 to reverse the vertical movement of the dozer blade. The control valve 1 has a spring which is connected via a piston rod 39a to a piston which is movable within the control cylinder 35. At the wheel cylinder 35, a switch lever 101 is mounted, which is provided with a centering spring 102, through which the shift lever is always maintained in an intermediate position when the control cylinder is actuated automatically 35 ₀ By this Pesthalten of the shift lever 101 in a middle Rosi tion during actuation As the control cylinder 35, the control valve 1 can be easily adjusted. The reference numeral 3 again denotes the solenoid valve for the vertical movement of the dozer blade. The line 32 contains a filter 31 “A line leads from the connection 3b of the solenoid valve 3 to the tank 86 and the connections 3c and 3d are connected via lines 33 and 34 to the head end or to the end of the control cylinder 35 on the piston rod side.

The solenoid valve 3 has a solenoid 40 for controlling the downward movement of the blade and a solenoid 41 for controlling its upward movement the limitation of the downward movement connected to a contact 8a of the contact group G _{1 of} a load acceptance limiting relay 8, while the second connection of the magnetic coil 41 via a limit switch 68 for the limitation of the upward movement with a contact 7a in the contact group B- a manual operation priority -Relay 7 and a contact 8o of the contact group O ^

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of the load limiting relay 8 is connected «Furthermore, the contact 5d of a safety relay 5 and the contact 7'd of the manual mode priority relay 7 are connected to the voltage source 42, while a contact 8 ^! b of the contact group Gp of the load limiting relay 8 via an overload indicator light 43 is located on the voltage source 42 ₀

A contact 5c of the contact group A ^ and a contact 5 Ό the · contact group Ap of the same safety relays 5 are an indicator lamp 54 for the automatic mode as well as a diode 12 bzwo via the display lamp 54 and a diode 13 to the voltage source 42 connected ₀ Further, the same contacts 5c and 5 ¹ C of the safety relay 5 connected via the diodes 12 and 13 to a contact 8 ⁹ O of the contact group C _{2 of} the load limiting relay 8. In addition, the contact 5c is connected to the contact spring 7'b of the contact group Bp of the manual mode priority relay 7 and the contact 5 ^! c with contact spring 7b of contact group B .. of relay 7 ο

The load limiting relay 8 contains a relay coil 8p which is connected to a load-receiving measuring circuit 11. Any type of load sensing arrangement can be used if it only provides a suitable electrical signal outputs, through which the relay coil 8p is always energized when the load on the "dozer blade a certain Value exceeded The contact tongue 8b of the contact group Ο., The load limiting relay 8 has a contact 7 * a of the contact group Bp of the manual mode priority relay 7 connected.

With the reference number 45 in Figo 5 is a selector switch for denotes the change between manual and automatic mode, A movable contact 45a of the selector switch 45 is connected to the voltage source 42 via a main switch 46 «

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A contact 451 'in switch 45, which is used to switch to automatic lowering movement of the dozer blade, is connected to contact tongue 5b of contact group A of safety relay 5 and a contact 45c for switching to automatic upward movement of the dozer blade is connected to contact spring 5'b The contact group Ap of the safety relay 5 connected. Finally, a contact 45d for manual operation is connected to a contact 5''d of the safety ^relay 5 One connection of a switch 56, which is coupled to the manual control lever 101, is connected to the voltage source 42 via the main switch 46, while the other connection of the switch 56 is connected to a contact 7d of the manual mode priority relay 7 _{or the like}

The operation of this control circuit will now be described

If the main switch 46 is engaged and at the same time the selector switch 45 is in manual mode, the contact tongues 5b, 5'b and 5 ^l! b of the safety relay 5 is moved to the right and closed. Furthermore, the contact tongues 7b and 7'b of the manual mode priority relay 7 are moved to the left and kept closed.

When the selector switch 45 on contact 45b for automatic downward movement of the blade is switched, a voltage signal passes through the contact group 0- of the load limiting relay 8 and the limit switch 69 to the magnetic coil 40 for the downward movement, since the relay 5 through the contact group A, remains in self-holding position. However, this switch position is only maintained if the load bearing capacity of the dozer blade a is small ₀ over-

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If the load intake exceeds a certain threshold, will the relay coil 8p of the load limiting relay 8 is energized and thereby the contact spring 8b of the contact group Cj applied to the contact 8o, so that a signal via the limit switch 68 to the solenoid 41 for the Upward movement is passed.

When the solenoid 4-0 for the downward movement of the dozer blade Receives voltage, the valve passages in the solenoid valve 3 for the vertical movement of the .flanierschildes D for the downward movement between the valve connections, whereby the control cylinder 35 is actuated in turn moves the control valve 1 for the vertical movement of the blade into the lowering position E, whereby the working cylinder 60 is acted upon so that it lowered the dozer blade

If, on the other hand, the solenoid 41 for the upward movement of the dozer blade receives voltage, the solenoid valve 3 is in the lifting position F moves, whereby the control cylinder 35 is operated in the opposite direction so that it controls the control valve 1 for the vertical movement of the dozer blade moved into the lifting position G, whereby the working cylinder 60 is acted upon in such a way that it lifts the dozer blade »

If the threshold value for the load absorption is undershot again during the upward movement, the load limiting relay drops 8 again and the magnetic coil 40 for the downward movement is activated again This cycle repeated"

Exceeds the dozer blade as it moves vertically a previously set lower or upper limit for the movement play, either the limit switch 69 for the limitation of the upward movement or the limit switch 68 for the limitation of the downward movement is opened, whereby the solenoid valve 3 for the vertical movement in his

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Neutral position H "moves and the dozer blade movement is stopped o

The dozer blade can also be made freely movable or raised and lowered by the switching lever 101. For this purpose, the switch 56, which is coupled to the switching lever 101, is disconnected, so that the circuit for automatic operation by the manual mode priority relay 7 opened and the automatic mode of operation is interrupted _o

6 shows the hydraulic circuit diagram of a fourth embodiment of a controller according to the invention, in this case Execution is the input 3a of the solenoid valve 3 via a valve 103 connected to a pump 104 and a bypass line 105 connects the suction and pressure sides of the Pump 104o In the bypass line 105 there is an overflow valve 106 «

The connection 3b of the solenoid valve 3 is via a line 107 to the input 1a of the control valve 1 for the vertical movement of the dozer blade connected, while from the terminal 3 "b of the solenoid valve 3 a line 108 to a Container 109 leads. The line 108 contains an overflow valve 110. A branch line branches off the line 107 from, which led to a connection 1b of the control valve 1 for the vertical movement of the dozer blade In the sub-line 111 a valve 112 is arranged ". Furthermore, a line 113" goes from the connection 1b to the container 109 "in which was a valve 114

A line also leads from connection 1c of control valve 1 115 to container 109 ο Line 115 contains a filter 116.

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A connection 3c of the solenoid valve 3 and a connection 1d of the control valve 1 are connected via lines 117 and 118, respectively connected to the end of the working cylinder 60 on the piston rod side for the vertical movement of the dozer blade » The head end of the working cylinder 60 hangs by means of pipes 119 or »120 at connections 3d and Ie of the solenoid valve 3 or of the control valve 1 »

The electrical circuit of this embodiment corresponds to that of the example described above »

When the solenoid 40 for the lowering movement is excited by a voltage signal, the solenoid valve 3 is in Lowering position D moved, whereby the working cylinder 60 is actuated so that the dozer blade moves downwards » On the other hand, when the solenoid 41 for the upward movement receives a voltage signal, the solenoid valve 3 is in the lifting position 1 moves, whereby'der working cylinder is operated in the opposite direction and lifted the dozer blade

Y / ird the control valve 1 for the vertical movement of the dozer blade operated by means of the shift lever 101 while the solenoid valve 3 is in the neutral position the control cylinder for moving the dozer blade can be switched directly by hand »

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Claims (1)

Pat entans prohe Control for the leveling blade of a leveling machine, which is provided with a working cylinder for lifting and lowering, characterized by an arrangement consisting the end - a solenoid valve (3) for controlling the working cylinder 60, - Switching means (45) for optionally switching between manual and automatic actuation of the dozer blade, - A safety relay connected to these switching means (45) (5), which can only be excited when this switching means (45) is in the position for manual operation, - A priority relay (7) for manual operation, which is used to receive a signal from the safety relay (5) is designed, - A load limiting relay (8) which is excited duroh a signal from a load acceptance measuring circuit (11) can, whereby there is a signal from the priority relay (7) to one of the solenoid coils (40,41) of the solenoid valve (3) forwards, as well as from - further switching means (47 »51; 56), the disconnection of which in conjunction with the actuation of a manual switch lever (67; 101) interrupts the circuit for automatic actuation in the priority relay (T) ₀ Control according to claim 1, characterized in that it is additionally provided with - a control cylinder (35), in which there is a leather on each side of the piston, and which is connected to the solenoid valve (3) is connected, and 609884/0274 - A control valve (1) for controlling the working cylinder (60), the control valve (1) with the a spring of the control cylinder (35) is connected » 3ο control according to claim 2, characterized in that the shift lever (101) is connected to one of the springs of the control cylinder (35). 4. Control according to claim 2, characterized in that the switching lever (101) is connected to the control valve (1) is. ο Control according to one of claims 1-4 for a dozer blade with a further working cylinder for the inclination, characterized in that it is additionally is provided with - A second solenoid valve (6) for switching on Free vertical mobility of the dozer blade, through which an overflow connection between the two Piston sides of the working cylinder (6) can be produced, and - A third solenoid valve (4), with which the further working cylinder (61) can be controlled for the inclined position of the dozer blade ₀ 6ο control according to claim 5 _t characterized in that this second solenoid valve (6) is connected to the control cylinder (35) _e 7ο control according to claim 5 or 6, characterized in that that a second control valve (2) for controlling the further ArheitBzylinders (61) for the inclination of the Dozer blade is provided, 809884/0274 25580H 8. Control according to claim 5 _}, characterized in that a flow divider (71) is provided between the solenoid valve (3) and the third solenoid valve (4) 609884/0274