EP0671512B1 - Hydraulic locking device for quick couplings in construction machines - Google Patents

Abstract

The locking system has at least one cylinder (3), containing at least one piston (64) connected to a locking bolt (8), via a piston rod (7). The piston is actuated by hydraulic pressure supplied by pipes (4,5) from a control valve (6). A device (19) connects the opposite faces of the piston, and can be situated inside the piston. The device can also be built into the hydraulic circuit external to the cylinder, and may take the form of a connection of smaller cross-section than the supply pipes, and may also contain an aperture.

Description

The invention relates to a hydraulically operated locking device for quick couplers on construction and work machines with the features of the preamble of Claim 1.

DE-C 42 10 790 describes a work machine, in particular Construction machine, known to have a recording equipment different tools is provided, and in which the change of work tools by means of a hydraulic actionable quick-change device can be brought about is, with several possibly in a control valve summarized spool are provided by means of which, if necessary, hydraulic cylinders in the area of the respective Tool and / or the quick-change device and / or the equipment receiving the work equipment can be actuated, in the hydraulic working group optionally at least one drain line leading to the tank and at least in the area of the working machine a line coupling station for optional recording not cables in use is provided. The the Hydraulic cylinder actuating quick-change device, especially plunger cylinder, is connected via a line connected to a connection of the line coupling station. The Leakage oil line leads from the line coupling station or from the hydraulic cylinder to the line coupling station running pipe to the tank.

For quick-change devices, especially for wheel loaders, in which double for the locking device acting hydraulic cylinders can be used due to the practically unavoidable technical Leakage of the assigned control valve in neutral position in the cylinder gradually on one or both sides of the piston to build up a pressure. The pressure builds on that Side of the piston on which to unlock the Quick change device leads, this can partially or completely unwanted and uncontrollable opening the locking device lead with associated safety-related dangers or malfunctions.

Solutions are known in which the leakage of the Control valves through interposed leak-free Seat valves (mechanically or electrically operated) prevented are. These solutions are expensive and mean additional operations.

The same solutions are known in which the locking side of the piston using a pressure valve with frequent actuated pressure circuits of other devices in connection stands. That means the locking side of the piston receives frequent pressure surges, causing a possible Unlocking movement should be counteracted. This Solution requires additional lines and an intermediate one Check valve. Another disadvantage of this The solution is that if the associated is not operated for a long time Pressure circuit that generates the pressure surges (e.g. for transfer journeys), the solution is ineffective.

From US-A-4,872,310 is an electro-hydraulic device known, by means of which from a rotating drive movement a linear piston movement of an engine should be generated. For this purpose, this device has a Synchronous cylinder with two pistons on both sides Piston rods on, with both piston surfaces due to the same cross-section of both piston rods is the same size. At the cylinders are to be acted upon of the two pressure chambers separated by the piston hydraulic lines connected via a hydraulic-mechanical Connection connected to the drive motor are. To manually interrupt the automatic drive process are the two hydraulic lines connected to each other via an additional line, whereby this line is normally closed by a valve and can be opened manually, so that manual Opening a pressure equalization in both hydraulic lines of the cylinder and thus a pressure equalization in the Cylinder adjusts so that the linear piston movement is interrupted becomes.

The aim of the subject of the invention is a technical to find an easier and effective solution in all cases, with what intended or unintentional unlocking the locking device can be safely avoided.

This goal is hydraulic with an inventive actuated locking device solved in that one on the piston surface side with the ring surface side Pressure chamber connecting device is provided, the is dimensioned so that with normal actuation the control valve still a problem-free locking and unlocking is possible.

In the solution of the locking device according to the invention, a double-acting hydraulic cylinder can be used by means of two Hydraulic lines and with a control valve required for actuation connected is. The hydraulic cylinder is on the cylinder and piston rod side each connected to a locking bolt, which in turn in Guides are stored. Now by operating the control valve Pressurized oil is applied to the cylinder through the supply line the surface of the piston has a force for locking via the locking bolt of equipment. Unlocking the device is also done by operating the control valve, the Pressurization of the cylinder takes place via a further supply line. Now builds up in the locked state of the device due to leaks in the control valve - the control valve is in neutral position - Pressure in one or both supply lines, the respective higher pressure due to a connection hole in the Pistons in both separated by the piston in the cylinder Clear effectively.

Since the piston area is much larger than the ring area of the piston, there is always a higher force on the piston side in the event of leaks, i.e. on the locking side. So is an unwanted and uncontrolled Opening of the lock excluded. The size of the hole is to choose so that the pressure drop is still with normal operation easy locking and unlocking of the quick-change device enables.

The advantages of the invention are seen in that they are technical is simple, safe and can be retrofitted to existing devices, minimal Costs and no additional operations included.

In a further solution of the locking device according to the invention a double-acting hydraulic cylinder is used, which by means of two Hydraulic lines with a control valve required for actuation connected is. The hydraulic cylinder is here with two pistons equipped, at the piston rod ends a locking bolt is attached. The bolts are stored in the guides. Is a hydraulic line with the actuation of the control valve Pressurized and thus also the annular surfaces of the pistons is the Device unlocked. The pistons are supported on a stop from, which is firmly connected to the interior of the cylinder.

On the other hand, the other hydraulic line becomes when the control valve is actuated pressurized, the pistons are pushed outwards, whereby the locking bolts into the corresponding locking recesses of the equipment.

Now builds in the locked state due to the quick-change device of leaks in the control valve - the control valve is located in Neutral position - pressure in one or both hydraulic lines this pressure is transferred to the cylinder via this hydraulic line (s). For example, due to a connecting line between The two hydraulic lines have the same piston on both sides Build up pressure. Now that the piston surfaces of the pistons are much larger than the opposite ring surfaces, there is a leak always a greater force in the locking direction than vice versa. Consequently an unwanted and uncontrolled opening of the device is excluded.

To ensure that the locking device functions correctly when actuated of the control valve must ensure that due to this connecting line Pressure drop between the hydraulic lines be kept within appropriate limits. This is preferably done by choosing a correspondingly small cross-section of a connecting line or by using an appropriate aperture in this Management.

Figuren 1 bis 3 -

hydraulisch betätigte Verriegelungsvorrichtungen für Schnellwechsler an Bau- und Arbeitsmaschinen in unterschiedlicher Ausführungsform.

The subject matter of the invention is illustrated in the drawing using an exemplary embodiment and is described as follows. Show it:

Figures 1 to 3 -

Hydraulically operated locking devices for quick couplers on construction and work machines in different designs.

Figure 1 shows a schematic diagram of a quick coupler 1, by means of which for example a shovel 2 with the equipment 2 'only indicated a wheel loader, not shown, can be connected. Of the In this example, quick coupler 1 contains a double-acting one Hydraulic cylinder 3, which is connected to one by means of two hydraulic lines 4, 5 control valve 6 required for actuation is connected. When actuated of the control valve 6 such that there is a pressure in the hydraulic line 5 builds up, the piston 64 is pushed to the left in the direction of the arrow, wherein the locking bolt 8 attached to the piston rod 7 into the opening 9 of the left receiving element connected to the blade 2 10 is pushed. To the same extent, due to the pressure build-up the cylinder 3 shifted to the right in the direction of the arrow, the one with the Cylinder 3 connected piston rod 11, i.e. the locking bolt hinged to it 12 in the opening 13 of the connected to the blade 2 right receiving element 14 is inserted. On the locking bolt 8,12 stops not shown are provided here, which on the Guides 15, 16 in the locked state of the quick coupler 1 to the system come. The unlocking takes place in the opposite sense, whereby over the Control valve a pressure is built up via the hydraulic line 4, so that the piston 64 and also the cylinder 3 are moved in reverse. The bolts 8, 12 slide out of the openings 9, 13 and remain within the guides 15, 16 of the equipment parts 2 '. The locked one Position is shown in dash-dotted lines.

Now builds up in the hydraulic line 4 and / or the hydraulic line 5 when the control valve 6 is in a neutral position, pressure is planted this in the piston surface side space 17 and / or the piston ring side Printing room 18 continues. Would the pressure be due only to room 18 build up unavoidable leaks in the control valve 6, so it could happen that over time piston 64 and cylinder 7 in the sense an unlock would move, the locking bolt 8, 12 out would slide out the openings 9,13 of the receiving elements 10,14. Around to reliably prevent this measure, one of the pistons 64 Cross-section brought small bore 19 which the two pressure chambers 17 and 18 connects. Since the cross section of the bore 19 is relatively is low, there will be a pressure build-up in space 17 or 18 Normal locking or unlocking does not negatively affect this function impact. In contrast, should the control valve 6 be in neutral position build up an undesirable pressure in the pressure chamber 18, for example this pressure by volume flow of the medium through the bore 19 in the Transfer pressure chamber 17 and therefore no gradual unlocking occur.

Figure 2 shows an alternative quick-change device 20, here two pistons 22, 23 are provided within a cylinder 21. The ones from Control valve 24 outgoing hydraulic lines 25, 26 are connected to the hydraulic cylinder 21 connected, the hydraulic line 25 is a branch 27 includes, which serves to supply the piston 23. Line 26 ends between the via an annular stop 28 within the Cylinder housing 21 'spaced pistons 22,23. Each of the pistons 22, 23 is with a piston rod 29,30 and a locking bolt articulated thereon 31,32 connected in a corresponding opening 33,34 of with, for example, the bucket 35 of a hydraulic excavator, not shown connected receiving elements 36,37 is introduced. The locked position is shown here in dash-dotted lines. Now a pressure is built up in the hydraulic line 26 via the control valve 24, this is planted in the common space 38 on the piston surface side so that both pistons 22, 23 are pressed outwards and the locking bolts 31,32 in the corresponding openings 33,34 of the receiving elements 36.37 slide. The quick-change device is in this state 20 locked. Conversely, by appropriate Pressure build-up in the hydraulic lines 25, 27 causes unlocking, whereby the pistons 22, 23 are pushed back as far as the stop 28 and the Locking bolts then remain within the guides 39, 40. Build now in the neutral position of the control valve 24 via the hydraulic lines 25, 27 and / or 26 a pressure in rooms 41, 42 and / or 38, Under certain circumstances, there may be an undesired unlocking of the locking bolts 31.32 come. To avoid this, there is between the hydraulic lines 25,26 a connecting line 43 is provided, which with a Aperture 44 is equipped. Because of this connecting line 43 between the hydraulic lines 25 and 26 is seen on over time Build up the same pressure on both sides of the pistons 22, 23. Because the piston surfaces the piston 22,23 much larger than its opposite Ring surfaces are always the result of leakage from the control valve 24 a greater force in the locking direction than vice versa. So is a unwanted and uncontrolled opening of the lock of the quick-change device 20 excluded.

Figure 3 shows a partial view of a double-acting cylinder 45, i. H. only one of the pistons 46 together with the piston rod 47, which in its end region 48 connectable with a locking bolt, not shown here is. The connection is in the area of the end face 49 of the cylinder 45 50 for the supply of the piston surface pressure chamber 52 and the Connection 51 is provided for the supply of the annular pressure chambers 53. The hydraulic medium passes through the connection 50, the bore 54 and the line 55 to the piston surface pressure chamber 52, while the Pressure medium via the connection 51, the bore 56 and the bore 57 and the line 58 reaches the pressure chambers 53 on the ring side. The connection of the two pressure chambers 52 and 53 is now brought about in that a circumferential annular groove in the component 59 containing the connections 50, 51 60 is introduced and the connection 50 via a tap hole 61 with the Ring groove 60 and thus connected to the terminal 51. Through this The measure can be taken if the pressure builds up on one or both sides in the area of the connections 50.51 a corresponding pressure adjustment in the pressure rooms 52.53 can be brought about over time. It is analogous to FIG within the cylinder housing 62 of the cylinder 45 an annular circumferential Stop 63 provided for the piston 46.

Claims (8)

1. Hydraulically actuated locking arrangement for quick-change devices on construction machines and driven machines, having at least one cylinder (3, 21, 45), which contains at least one piston (64, 22, 23, 46), and piston rods (7, 11, 29, 30, 47), which are assigned to the cylinders (3, 21, 45) and/or the piston or pistons (64, 22, 23, 46) and are provided with locking bolts (8, 12, 31, 32), if need be fastened thereto, hydraulic lines (4, 5, 25, 26, 27, 50, 51), via which pressure can be admitted to the piston or pistons (64, 22, 23, 46) and/or the cylinder (3, 21, 45) via at least one control valve (6, 24), being connected to the cylinder (3, 21, 45), each piston (64, 22, 23, 46) only having a piston rod (7, 11, 29, 30, 47) on one side in such a way that each piston (64, 22, 23, 46) subdivides the cylinder (3, 21, 45) into a piston-area-side pressure space (17, 38, 52) and a ring-area-side pressure space (18, 14, 42, 53), characterized in that a device (19, 43) connecting the piston-area-side pressure space (17, 38, 52) to the ring-area-side pressure space (18, 41, 42, 53) is provided, and this device (19, 43) is dimensioned in such a way that problem-free locking and unlocking is still possible during normal actuation via the control valve (6, 24).
2. Locking arrangement according to Claim 1, characterized in that the device (19) is formed by at least one bore, connecting the pressure spaces (17, 18) to one another, in the piston (64).
3. Locking arrangement according to Claim 1, characterized in that the device (43) is formed by a line connecting the hydraulic lines (25, 26) to one another.
4. Locking arrangement according to Claim 3, characterized in that a restrictor (44) is inserted into the connecting line (43).
5. Locking arrangement according to Claim 3, characterized in that the cross section of the connecting line (43) is designed to be smaller than the cross section of the hydraulic lines (25, 26).
6. Locking arrangement according to Claim 1, characterized in that, when the connections (50, 51) are arranged approximately at the same level of the cylinder (45), the component (59) surrounding the cylinder (45) is provided on the connection side with an at least partly encircling annular groove (60), and in that the pressure spaces (52, 53) are connected by a branch bore (61) starting from one of the connections (50) and extending into the annular groove (60).
7. Locking arrangement according to one or more of Claims 1 to 6, characterized in that, when two pistons (22, 23, 46) provided in each case with a piston rod (29, 30, 47) are used inside a cylinder (21, 45), a stop (28, 63) is provided for the pistons (22, 23, 46) in the cylinder housing (21', 62).
8. Locking arrangement according to Claim 7, characterized in that the stop (28, 63) is a ring firmly connected to the cylinder housing (21', 62).

Images