EP0256206A1 - Excavator, in particular an hydraulically and self-propelled little one - Google Patents

Abstract

The excavator of the present invention has wheels which are suspended or respectively attached in a special way. When the excavator moves or is transported, the wheels are in their vertical normal position and for excavating purposes preferably all wheels are tilted sideways. This measure increases the seating surface of the excavator and therefore its stability on the ground. For this purpose, the wheels are tiltingly attached to axle extensions which can be moved in the direction of the axle. The said axle extensions are pulled in when the excavator moves, and for excavating tasks are pushed out towards the side whereby the tilting of the wheels takes place. Pistons inside the axle effect the moving of the axle extensions.

Description

The invention relates to an excavator, in particular a self-propelled, hydraulic universal small excavator for earthworks, for laying supply lines, digging trenches, foundation holes, etc., with an excavator arm preferably arranged via a rotating device on a chassis, with control and drive devices, and with at least his pair of wheels supported at the ends of an axle.

Excavators of the aforementioned type are generally known and are used for a wide variety of work in a wide variety of environmental conditions. Even relatively small excavators, so-called universal small excavators, have to exert considerable tearing forces and breakaway forces, which in itself does not pose any difficulties from the motorization side. However, it is difficult, in particular with certain ground conditions, for example when working on hard surfaces, such as concrete, asphalt, etc., to fix the known excavators sufficiently locally so that they can also fully utilize the forces available per se. Additional stabilization measures, for example with extendable supports, are only partially successful. On the other hand, it is the user's wish that the excavators are also fully off-road, ie that they can also work on less solid ground, for example, and do not sink too deeply, that is, the contact pressure of the excavator should be as low as possible. It goes without saying that the pivot point of the excavator should also be as low as possible and, above all, that the excavator arm pivot point should be arranged as low as possible. Maneuverability, speed and compact design with a small space requirement are also important requirements required by the user. With the excavators known so far, these requirements could only be partially met. The reason for this is on the one hand that the highest possible wheels are required to make the excavator sufficiently off-road, i. H'. that he can drive over uneven floors with depressions and holes without touching down. On the other hand, the fulfillment of this requirement automatically becomes the focus of the excavator, and in particular the excavator arm pivot point, if a 360 ° rotation of a structure accommodating the excavator arm is desired. In the other case, as the wheels grow larger, the maneuverability of the body is reduced.

Based on these disadvantages that are more or less common in all known excavators, the object of the present invention is to improve excavators, in particular self-propelled hydraulic universal small excavators, in such a way that an increased stability is achieved in excavator operation compared to the known excavators and that while maintaining a 360 ° rotation of the excavator arm or the superstructure, the excavator center of gravity and the excavator arm pivot point can be set lower than is the case with comparable known excavators and a good soft soil suitability, i.e. H. a high level of sinking in should be achieved. In addition, during transport, i.e. H. in normal driving operation of the excavator, the speed should nevertheless not be less than that of comparable excavators, and good maneuverability and precise turning around its own axis should be possible.

The solution to this problem is that each wheel is connected to at least one axis laterally tiltable about a parallel to the longitudinal axis of the excavator and stabilized, tiltable in the erected position.

As a result, it is advantageously possible during excavator operation, in particular when the excavator is on soft ground or on sensitive ground such as Ornamental grass, works, or if particularly high tearing forces or breakaway forces are to be applied or if, for example, when digging a deep trench despite a particularly deep excavator arm pivot point and large wheels, a 360 ° rotatability of the structure is required, the wheels, preferably all existing wheels, of theirs tilt the normal vertical position sideways outwards so that the outside of the wheels comes into contact with the ground. This measure automatically lowers the height of the excavator right from the start, ie the excavator chassis is lower, which means that the center of gravity of the excavator is lower and thus avoiding tipping over, for example, on sloping terrain. By tilting the wheels, preferably to the side, the excavator arm pivot point can also be placed lower, so that, under the same conditions, deeper holes or trenches can be drilled, and yet the excavator arm can rotate through 360 °. By tilting the wheels, an additional increase in the ground support liability is achieved, nevertheless, with the same excavator weight, the support pressure, ie the pressure of the ground per unit area, is reduced. In addition, the tear force and breakaway force that can be applied by the excavator is increased by increasing the ground contact liability. Another advantage of the excavator according to the invention is that a sufficient speed of the excavator is achieved from place of use to place of use, because the wheels can be made sufficiently large, which has a recognizably favorable effect for the excavator transport. Another important advantage is the reduced space requirement, which is advantageous when working in tunnels or under bridges, for example. Should still be despite the tipped wheels the ground contact forces, for example, are not sufficient for extreme tearing work, it is possible to use supports and / or a dozer blade in the excavator according to the invention. The subject of the invention leaves much less traces in comparison to the known excavators, because it can have larger and possibly narrower wheels.

An advantageous development of the higher-level measures according to the invention is that the wheel suspension is each connected to at least one displaceable axle extension piece, which in turn is fixed in a retracted position close to the axle in excavator driving or transport operation and in an extended or extended position remote from the axle in excavator operation, whereby When the axle extension piece is extended, each wheel supported on it tilts outwards from the vertical normal or driving position and the outside of the wheel comes into contact with the ground.

An advantageous constructive embodiment of the axles that can be used in the context of the invention consists in that the axles are designed as hollow tubes, in each of which the axle extension pieces protrude laterally and are displaceable. A cylinder, preferably a hydraulic cylinder, is expediently used for the actuation or displacement of the axle extension pieces. This, in turn, can also be arranged in the hollow axis, thereby protecting it from dirt and damage. If the excavator is used on slopes or, for example, in trenches with side slopes, it is not necessary Lich, turn the wheels a full 90 ° to the side.

It is also advantageous to provide a roller attached to the chassis in order to be able to set up the wheels in a targeted and safe manner.

In order to be able to move the excavator quickly and gently from one place to another, for example by a tractor or by means of a self-propelled system, the wheels should be rubber-tired.

The invention is described in detail below using an exemplary embodiment, reference being made to the accompanying drawings.

• Figur 1 ein mit Einzelradaufhängungen versehenes Chassis eines erfindungsgemäßen Baggers in der Fahrstellung,
• Figur 2 die Anordnung gemäß Figur 1 bei Baggerbetrieb,
• Figur 3 eine teilweise geschnittene, schematische Seitenansicht des gesamten Baggers mit der Figur 1 entsprechender Radstellung,
• Figur 4 eine teilweise geschnittene, schematische Seitenansicht des Baggers mit der Figur 2 entsprechender Radstellung,
• Figur 5 ein mit spurparallelen Doppelradaufhängungen versehenes Baggerchassis in Figur 2 entsprechender Darstellung und
• Figur 6 eine schematische Draufsicht von unten auf ein mit zwei spurparallelen Doppelradaufhängungen versehenes Baggerchassis in der Fahrstellung.

The drawing shows:

• 1 shows a chassis of an excavator according to the invention provided with independent wheel suspension in the driving position,
• FIG. 2 shows the arrangement according to FIG. 1 during excavator operation,
• FIG. 3 shows a partially sectioned, schematic side view of the entire excavator with the wheel position corresponding to FIG. 1,
• FIG. 4 shows a partially sectioned, schematic side view of the excavator with the wheel position corresponding to FIG. 2,
• 5 shows an excavator chassis provided with parallel double wheel suspensions in FIG. 2 corresponding representation and
• Figure 6 is a schematic plan view from below of an excavator chassis provided with two track-parallel double wheel suspensions in the driving position.

The excavator on which FIGS. 1 to 6 are based is preferably a hydraulic, self-propelled universal small excavator which is particularly suitable for the work mentioned at the beginning. However, the present invention is not limited to such universal small excavators, but can also be used with advantage in all other known excavator types. FIG. 1 shows the chassis or the chassis 2 of the excavator 1 described in detail here. This comprises a front and a rear pair of wheels 3 and 4. The wheels 3 and 4 are individually accommodated here on associated cheek-shaped wheel suspensions 10 and in each case both on the side of axles 5, 6 attached to the chassis 2 parallel to each other. A pivot pin or a column 7 for receiving the superstructure or the tower is indicated approximately in the middle of the chassis.

According to the invention, the wheels 3, 4 are not rigidly attached to the respective axles 5 or 6 in the usual manner, but can be tilted. In the normal position shown in Figure 1, all wheels 3, 4 can rotate in the usual way, so that the excavator 1 is movable. For excavator operation, however, the wheels 3, 4 are tilted sideways, as can be seen in FIG. 2.

In the case of a mechanical drive of the wheels, the drive is uncoupled before or during the tipping process. Preferably, however, as FIGS. 3 and 4 show, tilting, individually controllable hydraulic motors 27 arranged on the wheels or wheel suspensions 10 can be used. When using hydraulic motors that can be supplied via flexible hoses, uncoupling when tipping is not necessary. Either all of the wheels or two diagonally opposite wheels are driven, which means that the excavator can be turned precisely.

In order to enable the wheels 3, 4 to tilt laterally, displaceable axle extension pieces 8 are provided, on which the wheels 3, 4 in FIGS. 1 to 4 are individually accommodated via their wheel suspensions. In each axis 5, 6, two opposite axis extension pieces 8 are slidably guided and each protrude from the axes 5, 6 at one end. The axes 5, 6 have a rectangular hollow cross section. To prevent rotation, the axis extension pieces have a cross-sectional configuration adapted to them. On each of the axle extension pieces 8, an individual fastening for one of the wheels 3, 4, that is to say a wheel suspension 10, is pivotably arranged here, for example via a bolt 9.

The tilted position shown in FIG. 2 enables the excavator to work, particularly on soft ground, since the contact surface has been significantly increased by the outer sides of the wheels 3, 4. As a result, the ground pressure per unit area is clearly reduced, with the focus of the excavator and the excavator arm rotation low point, which brings about the advantages specified in the introduction to the description. In the exemplary embodiment described here, the individual extension pieces 8 can each be brought from the retracted position shown in FIG. 1 to the extended position according to FIG. 2 with the aid of a cylinder-piston unit 11, 12. A hydraulic cylinder is preferably used for this. As can be seen from FIG. 3, this is preferably likewise arranged in the interior of the assigned axis 5 or 6. This protects it from dirt and damage. The cylinder-piston unit 11, 12 is secured in the interior of the axes 5 and 6, respectively, and actuated in the usual way. When using a simple, loosely arranged cylinder-piston unit, both the piston rod 12 and the cylinder 11 are each connected to an associated axis extension piece 8 via a bolt 13. When using an assembly with two pistons opposite each other in a cylinder, this can be arranged rigidly.

As shown in dashed lines in FIG. 4, the tilted tire 3 ¹ itself can first be pulled against a stop roller 16 and then be set up with a rolling motion. As can be seen from FIGS. 3 and 4, the uprighting movement of the wheels is limited on one side by stop pieces in the form of stop rails 14 fastened to the wheel suspensions 10. The arrangement of the stop rails 14 can be such that they run against a stop roller 16 when the wheels 3 or 4 are installed. For improved fixation or stabilization of the wheels these rest in the installed state on the wheel suspension 10 on a further chassis-fixed stop 28. This is located above the wheel pivot point. the stop roller is below this.

No stops are required for tipping. Tire grip is usually sufficient for this. To tilt the wheels 3, 4 are simply pushed outwards by the axle extension pieces 8. The pivot point of the wheels can be lower than the center of the wheel. The ground clearance of the wheel pivot point is equal to the distance to the outer wheel surface that comes into contact with the ground, so that the ground clearance of the chassis 2 remains the same. There is practically no upper limit on the wheel size. Nevertheless, when tilted wheels, can be performed 360 ^0- rotation of the rotatable chassis structure carrying the the directions indicated at 22 dipper arm.

According to FIGS. 3 and 4 ′, a rotary support 17 is arranged on the pivot pin 7, for example via a toothed ring (not shown in more detail). Above is a control tower 18 with control and operating levers 19, which are easily accessible from the seat 20 of the excavator 1. In addition, the excavator arm 22 is fastened to the rotary support or to a plate (not designated in more detail) arranged above it via a joint 21. The excavator arm 22 can be moved vertically by the joint 21, while the rotary movement takes place around the pin 7. By means of an additional device, the excavator arm 22 in the arrangement according to FIGS. 3, 4 can also be pivoted about the axis 21a parallel to the pin 7, which is a enables exact machining of the walls of trenches to be excavated with an excavator placed next to the trench.

If an additional increase in stability, for example for the execution of extreme tearing work or crushing or pushing work, is to be achieved with the tilted position of the wheels 3, 4 shown in FIG. 2, it is possible to do so on a push rod 23 attached dozer blade 24 to the ground. In addition, supports 25 which can be pivotably arranged on the chassis 2 of the excavator 1 can be brought to the ground. The dozer blade and supports are shown in Figure 3 offset by 90 ° for reasons of clarity.

For better adaptation to uneven floors, as shown in Figures 1 and 2, an axis, for. B. the axis 6 can be pivoted about a bolt 26. If both axes are designed to be pivotable, a lock, e.g. B.hydraulically., Which is advantageous even with a pivotable axis.

The basic structure of the arrangement according to FIGS. 5 and 6 corresponds to the arrangement according to FIGS. 1 to 4. The same reference numerals are therefore used for the same parts. The only exception is that the wheels 3, 4 are not individually accommodated on associated wheel suspensions. Rather, the wheels 3, 4 of each track are supported on a common double wheel suspension 30, which in turn is accommodated on the excavator chassis 2 so that it can be laterally tilted about a tilt axis parallel to the central longitudinal axis of the excavator. In the exemplary embodiment shown, this also has two axes 5, 6 running transversely to the longitudinal direction, which are provided on both sides with retractable and extendable axis extension pieces 8. The axle extension pieces 8, which are arranged on the same side in each case, are connected in a hinge-like manner by bolts 31 aligned in the longitudinal direction of the vehicle, each with a double wheel suspension 30 bridging them. The double support of the double wheel suspensions 30 and the bridging of the axles 5, 6 by the longitudinal double lateral suspension 30 result in a high stability. One of the axes 5, 6 can be tilted around a pin 26 running in the longitudinal direction of the excavator in order to achieve a good adaptation to the terrain, as in the above examples. In this case, in order to avoid constraining forces, the bolts 31 running in the longitudinal direction of the vehicle have a corresponding degree of freedom.

The dual wheel suspensions 30 provided here in tracks also enable a drive connection of the wheels 3, 4 of each track arranged one behind the other. In the illustrated embodiment, the front wheels 3 can be driven in the form of a hydraulic motor 27 by means of a drive motor coupled directly to each. The rear wheels 4 are connected by a transmission gear 32, in the form of a chain drive, to the respective adjacent front wheel 3. This results in all-wheel drive and yet only one drive motor is required per track, which reduces the construction effort. To accommodate the respectively assigned chain drive 32, the double wheel suspensions 30, each receiving a front wheel and the rear wheel connected to it in terms of drive, are designed as hollow box girders. This enables the transmission gears 32 to be accommodated in a protected manner. Accessibility can be ensured by means of suitable inspection flaps or the like. In the exemplary embodiment shown, the output shafts of the hydraulic motors 27 are connected directly to the respectively assigned front wheel 3 and provided with a chain wheel for driving the assigned rear wheel 4. The hydraulic motors 27 are accordingly arranged coaxially with the respectively assigned front wheel 3. However, it would also be readily conceivable to connect the two wheels of a track to one another in the intended manner by means of a transmission gear in the form of a chain drive, etc. and to introduce the drive torque into the transmission gear outside of a wheel axle, should this be desired in terms of space.

With regard to the accomplishment of the tilting and raising movement of the double wheel suspensions 30, practically the same applies as for the independent wheel suspensions 10 according to FIGS. 1 to 4. The same applies to the safe stabilization of the double wheel suspensions 30 while driving position. For this purpose, the chassis 2 can be provided with stops of the type indicated in FIGS. 3 and 4 at 16 and 28, not shown in detail here, which are offset upwards or downwards relative to the tilting axis, on which the box-shaped double wheel suspensions 30 with their inside for contact come. Corresponding system cams 33 are indicated schematically in FIG. The actuation of the axle extension pieces 8 acting on the wheel suspensions 30 can take place in the manner described in connection with FIGS. 1 to 4 by means of individual drive devices arranged in the area of the axles 5 and 6 in the form of respectively assigned cylinder-piston assemblies. The respective two axle extensions 8 connecting double wheel suspensions 30 also enable the drive units to be reduced in this regard, as indicated schematically in FIG.

6 shows in the right half an example with a cylinder-piston unit 34 which engages in the center on the assigned double wheel suspension 30 and is supported on the chassis 2 on the other side. In the left half of FIG. 6 there is a rotary motor 35 for retracting and extending the axle extension pieces 8 , for example in the form of a hydraulic rotary piston engine, use. To synchronize the axially extending pieces 8 of the two axles 5, 6, which are to be actuated in pairs and act on the same wheel suspension, a synchronizing shaft 36, bridging the distance between the axially extending pieces 8, which can be actuated in pairs, is used, which has axially mounted gearwheels 37 im which are assigned to the two axles 8 Engagement with racks 38 placed on the assigned axis extension pieces 8. The To avoid constraining forces, gear wheels 37 can be designed cambered in relation to the pivotability of the axis 6 provided here with respect to the bolt 26. To accommodate the racks 38, the axis extension pieces 8 can be provided with chamber-shaped recesses, so that despite the required toothing, reliable longitudinal guidance of the axis extension pieces 8 in the associated axis 5, 6 is ensured. To compensate for a u. U. possible twisting of the synchronizing shafts 36, the racks 38 can be arranged adjustable.

In the embodiment according to FIG. 6, on the right, with an extension device in the form of the cylinder-piston unit 34, which acts directly on the wheel suspension 30, the synchronizing shaft 36 is simply freely rotatable. An arrangement of this type can also be used in the case of individually driven axle extension pieces 8, for example of the type on which FIGS. 1 to 4 are based, provided mechanical synchronization is desired. In the embodiment shown on the left in FIG. 6, the synchronizing shaft 36 is driven directly by means of the rotary motor 35. The synchronizing shaft 36 is accordingly connected in terms of drive to the motor 35 attached to the chassis 2, for example inserted through the rotor and wedged therewith.

As the preceding explanations show, the principle on which the invention is based is not only applicable to the exemplary embodiments described in connection with FIGS. 1 to 6. For example, the double wheel suspensions 30 according to FIGS. 5 and 6 could also be arranged on only one axis extension arranged to prevent tipping tion piece be added so that there would be a cross-shaped chassis shape instead of the H-shaped chassis. It would also be conceivable to synchronize the axis extension pieces 8 in pairs in the embodiment according to FIGS. 1 to 4 and to move them by means of a common actuating device.

Claims (12)

1. Excavator, in particular self-propelled, hydraulic universal small excavator for earthworks, for laying supply lines, digging trenches, foundation holes and the like, with an excavator arm (22) preferably arranged via a rotating device on a chassis, with control and drive devices and with at least one pair of wheels supported at the ends of an axle (5, 6), characterized in that each wheel (3 or 4) with at least one axle (5 or 6) can be laterally tipped about a tilting axis running parallel to the longitudinal axis of the excavator and stabilized in the erected position connected is. 2. Excavator n-ach claim 1, characterized in that on the chassis (2) of the excavator at least one preferably rectangular hollow cross-section having axis (5 or 6) with two assigned to the two tracks, insertable and extendable, preferably corresponding rectangular cross-section having axis extension pieces (8) is provided, which is in the excavator driving or transport operation in a retracted position close to the axis and in the excavator operation in an extended position Genen or pushed out, off-axis position are held, each wheel (3 or 4) supported on it tilts outwards from the vertical-normal or driving position when extending each axle extension piece (8), so that in each case the outside of the wheel (3rd or 4) comes into contact with the ground. 3. Excavator according to one of the preceding claims, characterized in that on each axle extension piece (8) of the two axles (5, 6) preferably provided, an associated wheel (3 or 4) is individually tiltably received, preferably at the outer ends Each axle extension piece (8) is supported in each case by a bolt (9) running in the longitudinal direction of the vehicle, a cheek-shaped independent wheel suspension (10) which receives a wheel (3 or 4) and can be pivoted outward by approximately 90 °. 4. Excavator according to one of the preceding claims 1 to 2, characterized in that the wheels (3 or 4) are supported in pairs on a common double wheel suspension (30), which on at least one associated axle extension piece (8) preferably on two synchronously movable axis extension pieces (8) of parallel axes (5, 6) is pivotably received about a bolt (31) running in the longitudinal direction of the vehicle. 5. Excavator according to claim 4, characterized in that each of a double wheel suspension (30) engaging axle extensions (8) with one Gear rack (38) and are connected to each other in terms of drive by a synchronizing shaft (36) carrying gears (38) which cooperate with it and which is assigned at least one drive device (34 or 35). 6. Excavator according to at least one of the preceding claims, characterized in that / at least two of the preferably rubber tires (3, 4), - preferably two diagonally opposite wheels (3, 4) with this or on the associated wheel suspensions (10 or 3 =), preferably designed as hydraulic motors, drive devices (27) are provided. 7. Excavator according to one of the preceding claims 4 to 6, characterized in that the two wheels (3, 4) receiving double wheel suspensions (30) are designed as box girders, in each of which one with a drive device (27) cooperating, designed as a chain drive Transmission gear (32) is received, through which the two assigned wheels (3, 4) are connected to one another in terms of drive. 8. Excavator according to one of the preceding claims 2 to 7, characterized in that opposite axis extension pieces (8) by at least one, preferably in the associated axis (5, 6) positioned cylinder-piston unit (11, 12) are displaceable. 9. Excavator according to one of the preceding claims, characterized in that the raising movement of the wheels (3, 4) by at least one wheel suspension side, preferably two wheel suspension side, each on a chassis or axle-side counter stop (16 or 28) can be brought to abutment or bringable stops (14 or 33) is limited. 10. Excavator according to one of the preceding claims, characterized in that each wheel suspension (10 or 30) is assigned at least one chassis-fixed roller on which at least one assigned wheel (3 or 4) or a stop attached to the wheel suspension (14 ) runs up during the installation process. 11. Excavator according to one of the preceding claims, characterized in that at least one axis (6) about a preferably extending in the longitudinal direction of the bolt (26) is received tiltably on the chassis (2) and that preferably at least one tiltable axis (6) by means of a preferably hydraulic lock is lockable. 12. Excavator according to one of the preceding claims, characterized in that the tilt axis (pin 9 or 31) of the wheels (3, 4) or the wheel suspensions receiving them (10, 30) is lower than the wheel center and has a ground clearance, which is approximately equal to the distance between the outer sides of the wheels (3, 4), which in the tilted state come into contact with the floor and the tilt axis, so that the chassis (2) in the tilted and non-tilted state of the wheels (3, 4) is approximately the has the same horizontal height.

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