DE2803854A1 - Parallel guide for vehicle mounted front loader - has indicator cylinders as integral components of lifting cylinders with two position control valve - Google Patents

Abstract

The parallel guide is for a vehicle-mounted front loader, which is fixed to the end of a front loader arm connected with the vehicle. There is a lifting cylinder, a double-acting, implement tipping cylinder and an indicator cylinder which senses the front loader angle. An hydraulic servo valve is provided for the lifting cylinder and the tipping cylinder. Each indicator cylinder (14, 14') is an integral component of a lifting cylinder (10, 12). An additional control valve (40) has two positions. In its neutral position, it has a channel connected with each cylinder chamber (33 or 34) of the tipping cylinder and with each lifting cylinder (13) or indicator cylinder (14'). In its other position there is only one channel to connect all the lifting cylinders (13) with all the indicator cylinders (14').

Description

description

The invention relates to a parallel guide device for a Front loader implement or the like attached to a vehicle, which is rotatable at the end of one with its opposite end also rotatable with the vehicle connected front loader arm or the like. Is attached, each with at least one Front loader lift cylinder, a double-acting implement tipping cylinder, a the master cylinder scanning the front loader angle, and each with a hydraulic control valve for the lift cylinder and the tilt cylinder.

Work equipment attached to vehicles such as lifting platforms, work stands, Pallet forks and front loader implements should be horizontal at every height or can adhere to a predetermined position. While the needed for this purpose In the past, parallel guiding device by purely mechanical means such as rods, Ropes or chains have been implemented, one has recently been practicing more and more, to use hydraulic parallel guiding devices.

When using the hydraulic parallel guide device listed at the beginning on front loaders it has been shown that with the given space and power relations difficult in connection with the extreme oil pressure fluctuations that are common with front loaders is to accommodate the master cylinder in addition to the lifting cylinders. Further Difficulties arise from the fact that the tilt cylinder used for the parallel guidance additionally transfer tilting movements to the implement in every fork position must, for example to tilt or dump a load.

The object of the invention is to provide a parallel guide device of the initially described to train said type so that the master cylinder space-saving and power-wise neutral is housed, and also to simplify the parallel guidance overall.

Furthermore, the possibility of parallel guidance should be retained to be able to switch off arbitrarily at any time.

According to the invention this object is achieved in that each master cylinder is an integral part of a lifting cylinder, and that an additional control valve is provided with two positions, which in its zero position each have a through channel for connecting a respective cylinder space of the tilt cylinder (s) to each lifting cylinder or each master cylinder and in its other position only one through-channel to connect all lifting cylinders with all master cylinders.

In this way, the space and strength problems that have arisen so far are eliminated overcome in a simple manner, the overall device simplified and cheaper designed. The tilting cylinders used so far can be easily converted into the new Include parallel guide device, provided the master cylinder is integrated in the lifting cylinder is matched in terms of volume.

The lifting cylinder can advantageously be designed as a hollow piston be which the master cylinder for the essentially fixed to the lifting cylinder connected master piston forms.

Advantageously, the master piston can oscillate and / or move radially be suspended in the lifting cylinder.

The control valve can advantageously be a solenoid valve, which assumes its rest position in the de-energized state.

For operation, it can be advantageous if the control valve for the tilt cylinder at least one electrical control contact for the control valve assigned. Furthermore, the tilt cylinder can have electrical end position control contacts be assigned for the control valve.

The invention is described below with reference to a drawing explained in more detail. 1 shows a schematic side view of a with equipped with the parallel guide device described below n front loader vehicle, 2 shows a side view, cut away from one side, of a combined cylinder unit of the front loader of FIG. 1, and FIG. 3 shows a schematic electro-hydraulic overall circuit diagram for the front loader of Fig. 1.

The front loader vehicle 1 shown schematically in FIG. 1 is on its front part about a pivot point by means of a detailed below described combined cylinder unit 10 up and down front loader arm 2. To a mounted at the front end of the front loader arm 2 bearing 3 is a in the present case designed as a lifting fork working device 4 rotatably mounted. Instead of this lifting fork can also a working platform a trough o. The like. Be available as a tiltable implement.

The implement 4 is overall with the front loader arm 2 over a linkage 5 designed as a four-bar linkage is connected. By means of a between Front loader arm 2 and linkage 5 arranged hydraulic tilt cylinder 30 The implement 4 can be drawn from a horizontal or parallel position denoted by B. into a tilted tilted position A, a tilted tilted position C and any Bring intermediate position. As will be explained below, in a specific Operating state of the hydraulic system, the implement 4 when raising or lowering the front loader arm 2 in every selectable tilt position parallel to itself guided.

At this point it should be noted that the following will be described in detail hydraulic parallel guide device or

Work implement actuator both the combined cylinder unit 10 as well as the tilt cylinder 30 in duplicate, once for each side the front loader arm 2 are available.

The combined cylinder unit 10 shown separately in FIG. 2 contains a lifting cylinder 12 with eye 18 for articulation either to the front loader arm 2 or to the vehicle 1. In the lifting cylinder 12 is a hollow lifting lever 14 axially displaceable. The reciprocating piston 14 is an eye 19 for articulation either on Vehicle 1 or assigned to the front loader arm 2.

The reciprocating piston 14, which is open at its free end face, forms with his Cavity the master cylinder 14 'for a master piston 16, which is opposite the eye 18 is fixed and protrudes into the master cylinder 14 '. It is important, that the volume ratios between tilt cylinder 30 and master cylinder 14 'on the Leverage ratios in the parallel linkage 5 (Fig. 1) are matched because these two Cylinders interact to achieve parallel guidance when the system is set to "parallel guidance" is switched.

One between the inside of the lift cylinder 12 and the outside of the hollow reciprocating piston 14 formed cylinder space 13 is via a line connection 20 in connection with the hydraulic system shown in FIG. 3. The cylinder space 13 is pressurized to lift the fork 2. The master cylinder 14 'is limited together with the master piston 16, a cylinder space 17; this stands over a second Line connection 21 also in connection with the hydraulic system.

As can be seen from Fig. 2, the master piston 16 is "floating" suspended in the lifting cylinder cover labeled 26. Be that way Sealing difficulties avoided. To carry out this floating suspension is located in the eye 18, which is the extension of the lifting cylinder cover 26 forms, a transverse bore into which a pin 25 is firmly inserted, for example welded is. In a piston eye 23 of reduced diameter, which is inserted into a bore 26a engages in lifting cylinder cover 26 and eye 18 with play, is also located a transverse bore 23a through which the pin 25 penetrates with play.

At the end of the combined cylinder unit opposite the eye 18 10 is the eye connected to the outer end of the hollow reciprocating piston 14 19. As a seal between the lifting cylinder 12 on the one hand and the opposite of this from mobile reciprocating pistons 14 serves a cylinder space 13 according to externally delimiting sealing sleeve 71, which has two annular grooves on the inside, into which a seal 72a and an elastic wiper ring 72b are inserted. as A snap ring 73 is used to secure the sealing sleeve 71.

The inner cylinder space 17 of the cylinder unit 10 is between the Inside of the hollow reciprocating piston 14 (master cylinder 14 ') and the outside of the master piston 16 sealed by a sealing sleeve 76. This has three ring grooves on the inside, inserted into the one behind the other guide strips 77a and the seals 77b are.

The sealing sleeve 76 is by welding or in a similar manner with connected to the end of the hollow reciprocating piston 14.

As an extension limit for the hollow piston 14 with respect to the lifting cylinder A snap ring 79 inserted into a groove in the reciprocating piston is used.

Now to the description of the hydraulic system shown in FIG for the vehicle with front loader and front loader implement of Fig. 1. The two Line connections 20 of the lifting cylinder spaces 13 of the two combined cylinder units 10 are connected to one another via a branch line 94, with a manually operable one Control valve 50 and with a connection of the electromagnetically actuated control valve 40 connected. The line connections 21 for the master cylinder spaces 17 in the two Combined cylinder units 10 are connected to one another via another line branch 95 and also connected to the other port on the control valve 40. Another Line branch 96 leads from a further connection of the control valve 40, which the connection for the branch line 95 is opposite, on the one hand to a manual actuatable control valve 60 for the pressure side of the tilt cylinder 30 and on the other hand to the two rear cylinder chambers 34, 34 of the two tilt cylinders 30. A fourth Line branch 97 leads from the last connection of the control valve 40, which is the connection for the branch 94 opposite, on the one hand to the tension side of the control valve 60 and on the other hand to the two front cylinder chambers 33, 33 of the tilt cylinder 30. The tilting cylinder 30 is divided into the front and rear cylinder space by one piston 31 each. The piston rods are each through the front cylinder space 33 outwards.

The control valve 50 is connected to a hydraulic pump via a pressure line 90 connected, and also a discharge line 92 is in the direction of a reservoir 91 for hydraulic fluid available. However, this derivation is via the control valve 60 and only actually to the storage container 91 in its zero position b switched through. Both control valves 50 and 60 each have three manually adjustable ones Operating positions, which are designated with a, b and c, respectively.

The control valve 40 is used to establish a connection between the oil circuit the lift master cylinder 10 and the oil circuit of the tilt cylinder 30 to produce or at Also interrupt. This need arises when the front loader implement can be adjusted by manual switching of the control valve 60 via the tilt cylinder target. In this case, there must be no oil connection to the stroke master cylinder 10 be.

The connection between the master cylinder 17 and the tilt cylinder 30 is interrupted or there is a short circuit between the master cylinder 17 and the lifting cylinder 13 produced when the tilt cylinder 30 reaches the upper or lower end position and therefore no longer on the automatic oil supply or oil supply of the master cylinder 17 can react. The control valve 40 includes an electromagnet 41, which in the present case Trap is designed for an operating voltage of 12 volts. Above electrical Control lines 43, this electromagnet is excited when limit switch contacts are touched 45 or 46 or 47 the circuit is closed. The control valve switches 40 from the de-energized connection position "zero" shown in the drawing into the Short-circuit position 1.

The contact 45 is designed as a command contact, which is already responds when the control handle of the manual control valve 60, without switching, is touched.

Limit switch contacts 46 and 47 are one of the two tilt cylinders 30 assigned in such a way that when the piston rod is almost completely extended an attached actuating arm 35 the limit switch contact 46, and almost completely in the retracted state, the limit switch contact 4 / is triggered.

At least one limit switch contact 46 is designed to be adjustable. If the electric agent 41 receives its operating voltage, the control valve switches 40 in its short-circuit position, denoted by I, in which the line branches 94 and 95 are short-circuited; this means that in the operating state I of the control valve 40 of the stroke cylinder space 13 directly with the master cylinder space 17 in the combined Cylinder unit 10 is connected, in both cylinder units at the same time.

As already mentioned, the manually operated control valve 50 for the lifting cylinder 12 in the combined cylinder unit 10 has three operating positions a, b and c.

The operating position b shown in Fig. 3 is the rest position, the hydraulic fluid under pressure flows back into the reservoir 91 unused. In the operating position a, however, the line branch 94 is directly connected to the hydraulic pump 90 connected, both stroke cylinder chambers 13 in the cylinder units 10 are filled, the front loader arm 2 rises (see. Fig. 1). By switching the Control valve 50 to operating position c, the front loader arm 2 is lowered, since both the pressure oil of the pump 90 and the return oil of the pressure cylinder 10 via the discharge line 92 can drain.

During the lifting and lowering it is electromagnetic actuated control valve 40 normally in its rest position zero, since the control valve 60 assumes its rest position b shown in FIG. 3, in which the control handle actuating contact 45 associated with this control valve is not actuated. There in the Rest position zero of the control valve 40 of the line branch 94 with the line branch 97, and branch line 95 is connected to branch line 96, occurs at each Hub or Lowering movement of the front loader arm 2 the hydraulic parallel guide device automatically in function. When extending the lifting cylinder 12, i.e. when lifting the Front loader swing 2 automatically becomes the master piston connected to the lifting cylinder 12 16 pulled out of the master cylinder chamber 17, i.e. the volume of the cylinder chamber 17 enlarges.

Due to this enlargement of the cylinder space, through the branch 97 piston 31 loaded with hydraulic fluid in its front cylinder chamber 33 Displaced fluid from the rear cylinder chamber 34 and via the branch line 96 pushed into the cylinder space 17 of the combined cylinder unit 10. That means that when the lifting cylinder 12 is extended when the front loader arm is raised 2 the piston rod of each tilt cylinder 30 is automatically retracted so that the on the front loading arm 2 pivotably attached implement 4 tracked in parallel will. This parallel tracking can be designated with B in FIG. 1, for example Horizontal position or in any other position beforehand via the control valve 60 set tilt position take place. By moving the control valve 60 in operating position a can, after having previously been done by resetting the control valve 50 has fixed the front loader arm in its rest position b, the implement 4 pivot in the direction of its tilted tilt position A. In this case the line branch 96 is directly connected to the hydraulic pump 90, the rear Cylinder chambers 34 of the tilt cylinder 30 fill up, the piston rods extend. The tilting in the direction of the tilting position C of the implement 4 is carried out by Switching the control valve 60 to the operating position c.

Automatic is in operating position a and c of the control valve 60 for example, the actuating contacts 45 actuated via its control handle, so that the electromagnet 41 draws current and the control valve 40 is in its operating position I toggles. In this operating position I are the two branches 96 and 97 separated from each other, and each of them is connected to the hydraulic pump 90 and the other connected to the storage container 91.

The master piston 16 built into the combined cylinder unit 10 In parallel guidance operation, it reduces the entire reciprocating piston area by its piston area. There is a loss of lifting power, which is partially offset by the fact that the Pressure oil coming from the control valve 50 with the area ratio in the tilt cylinder 30 reduced pressure from the cylinder chamber 34 into the master cylinder 17 is and so on the master piston 16 and thus supporting the piston surface works.

Is activated when the front loader arm 2 is lifted by switching the control valve 50 also touches the control handle of the control valve 60, the hydr.

Parallel guidance from, the pressurized oil flows short-circuited via the control valve 40 Position I with full operating pressure on the master piston 16, which in the combined Stroke master cylinder 10 the entire area is fully applied. The lifting cylinder 10 works lossless.

This same effect occurs when in the lower front loader position the implement 4 is completely tilted (position A Fig. 1). The limit switch contact 46 now switches the control valve 40 to short-circuit position I. This works the Lift cylinder 10 lossless. Since in this operating state the hydr. Parallel guidance is switched off, the front loader implement 4 tilts with the change in angle the front loader arm 2 continues to rise when lifting. In the lower stroke range this is at loose bulk goods advantageous. By briefly switching the control valve 60 to any Loading height triggers the limit switch is 46 and the hydr. Parallel guidance is again w r.szm.

Furthermore, this limit switch contact 46 prevents that when lowering the front loader 2 with the implement 4 fully tilted (piston 31 from Tilting cylinder 30 in the uppermost position) which inevitably plunges into the cavity 17 Master piston 16 builds up a back pressure that would make lowering impossible.

The limit switch contact 47 prevents that when lifting the front loader 2 with the working device 4 completely tipped out (piston 31 of the tilt cylinder 30 in the lowest Position) in the master cylinder space 17 a vacuum is created.

Claims (8)

Parallel guiding device for a vehicle front loader implement or the like loader working device 0. Claims 1. Parallel guide device for a mounted on a vehicle Front loader implement o. The like. Which rotatable at the end of one with its opposite End also rotatably connected to the vehicle front loader arm or the like. Attached is, with at least one front loader lifting cylinder, a double-acting Arbeitsyerät tilt cylinder, a C.eberylinder that scans the front loader angle, and with one hydraulic control valve each for the lifting cylinder and the tilting cylinder, characterized in that each master cylinder (14, 14 ') is an integral part a lifting cylinder (10, 12), and that an additional control valve (40) with two positions is provided, which in its zero position each have a passage channel for connecting a cylinder space (33 or 34) of the (the) Tilt cylinder (s) (30) with each HubZynJer (13) or each master cylinder (14 ') and in its other position only one through-channel to connect all the lifting cylinders (13) with all master cylinders (14 '). 2. parallel guide device according to claim 1, characterized in that that the lifting cylinder piston (14) is a hollow piston, which the master cylinder (14 ') for the master piston (16) which is essentially firmly connected to the lifting cylinder (12) forms. 3. Device according to claim 2, characterized in that the master piston (16) is connected to the lifting cylinder (12) in a pendulous and / or radially movable manner. 4. Device according to claim 3, characterized in that the Geberk live (16) in a fastening eye (18) of the IIubz-l ders (12) through a cross to the cylinder axis running pin (25), which with clearance fit in a transverse bore (23a) engages at the end of the master piston with which the lifting cylinder is connected. 5. Device according to claim 1, characterized in that the control valve (40) is a solenoid valve which, when de-energized, is in its rest position (zero) occupies. 6. Device according to claim 5, characterized in that the control valve (60) for the tilt cylinder (30) electrical control contacts (45) for the control valve (49). 7. Device according to claim 1 and 5, characterized in that the tilt cylinder (30) electrical end position control contacts (46, 47) for the control valve (40) are ordered. 8. Device according to claim 6 or 7, characterized in that at least one of the control contacts (e.g. 46) is adjustable.