EP0256206B1 - 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 and the like, with an excavator arm preferably arranged via a rotating device on a chassis, with control and drive devices and with at least one pair of wheels, each wheel running parallel to the longitudinal axis of the excavator Tilting can be tilted sideways and stabilized in the upright position.

An arrangement of this type is known from US-A 4 241 803. In this known arrangement, the wheels are mounted on associated rockers, which are pivotably mounted on the vehicle chassis about a vertical and a horizontal axis. Swinging of this type causes a comparatively large space requirement in the driving position, since in the driving position they protrude from the vehicle chassis transversely to the direction of travel and cannot be shortened. In addition, this known arrangement requires both swing arm and swing devices for Tilting the wheels and therefore proves to be comparatively complex.

FR-A 2 139 828 shows a similar excavator. This is a dredger with a pair of wheels supported on associated support legs which are pivotally mounted on the vehicle chassis about a horizontal and a vertical axis. In this known arrangement, the support legs are placed parallel to the direction of travel in the driving position. As a result, the vehicle width is reduced, but the vehicle length is increased. With this known arrangement there is therefore a large space requirement in the driving position.

A particular disadvantage of the above-mentioned application can be seen in the fact that it is not possible to tilt or raise the wheels simply by actuating the wings or support legs. Rather, the tipping or uprighting process takes place separately from the setting of the wings or support legs. The change between driving position and operating position and vice versa therefore requires comparatively large adjustment intervals, which can have an unfavorable effect on the economy, in particular of a small excavator.

Proceeding from this, it is therefore the object of the present invention to improve an excavator of the type mentioned at the outset with simple and inexpensive means so that it is free from the disadvantages described above.

This object is achieved in that at least one axle with two to the chassis of the excavator Axle extension pieces associated with both tilting ashes are provided, at the ends of which at least one wheel is tiltably supported around one of the tilting axles and which is held in an attracted position close to the axis in excavator driving or transport mode and in an extended position remote from the axis in excavator mode be, when each axle extension piece each wheel supported on it tilts from the vertical normal or driving position to the outside in the lying position.

These measures ensure that, despite the large support surface and large support spacing in the excavator position, a compact structure with a small space requirement in the driving position is achieved. In addition, the measures according to the invention ensure that the wheels can be tilted or erected simply by retracting or extending the axle extension pieces, so that one and the same movement can be used to switch from excavator operation to driving operation and vice versa. This therefore results in comparatively short intervals, which has an advantageous effect on the economy, in particular of a small excavator.

Advantageous further developments and expedient refinements of the superordinate measures are specified in the subclaims. For example, the axles can be designed as hollow tubes in 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 axis extension pieces. This can 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 in trenches with side slopes, it is not necessary 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 means of a tractor or a self-propelled system, the wheels should have rubber tires.

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 significantly reduced, with the center of gravity of the excavator and the excavator arm pivot point 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 Figure 4, the tilted tire 3 'itself can first be pulled up against a stop roller 16 and then 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 the wheels are tilted, the rotatable chassis structure carrying the excavator arm indicated at 22 can be rotated 360 °.

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). 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 can be seen in FIGS. 1 and 2, an axis, for example the axis 6, can be pivoted about a bolt 26. If both axes are designed to be pivotable, a lock, for example hydraulically, should be provided, which is also advantageous in the case of 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 tilted laterally 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 suspension 30 and the bridging of the axles 5, 6 through 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. To avoid constraining forces, the bolts 31 running in the longitudinal direction of the vehicle in this case 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 secure stabilization of the double wheel suspensions 30 in the 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 Gears 37 can be designed to avoid constraining forces due 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 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 each be mounted on only one axle extension piece that was arranged to prevent tilting be included, 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. An excavator, more particularly a hydraulic general purpose light duty excavator for soil for excavating the ground and similar purposes, comprising an excavator arm (22) preferably arranged by means of a rotary device (22) on a chassis, control and drive devices and at least one pair of wheels, each wheel (3 and 4) being able to be tilted about an axis which is parallel to the longitudinal axis of the excavator, to the side and being able to be steadied and held in the erected position, characterized in that on the chassis (2) of the excavator there is at least one axle (5 and 6) provided with two axle extension members (8) which are associated with the two axes of tilt and are able to be extended and retracted and on the ends thereof in each case at least one wheel (3 and 4) is borne which is able to be rocked about one of the tilt axes and which during travel of the excavator between sites are held in a retracted position near the axle and during excavating operations is held in a extended position remote from the axle, and when each axle extension member (8) is being extended each wheel (3 and 4) borne thereon tilts from the vertical normal or, respectively, travel position outwards into the horizontal position.

2. The excavator as claimed in claim 1, characterized in that each axle (5 and, respectively, 6) is in the form of a tube with a rectangular cross section, in which the laterally protruding axle extension members (8), which have a corresponding cross rectangular cross section, are slidingly mounted.

3. The excavator as claimed in either of the preceding claims, characterized in that each axle extension member (8) of the preferably provided two axles (5 and 6) bears a respectively associated wheel (3 and, respectively, 4) in such a manner that same may be tilted, and preferably on the outer ends of each axle extension member (8) there is mounted, by way of a bolt (9) running in the longitudinal direction of the vehicle, a respective single wheel suspension means (10) which is able to be tilted through approximately 90° outwards, is in the form of a jaw, and mounts a respective wheel (3 and, respectively, 4).

4. The excavator as claimed in either of the preceding claims 1 and 2, characterized in that the wheels (3 and, respectively, 4) are arranged in accordance with track pairs respectively on a common double wheel suspension means (30) and such suspension means is mounted on at least one associated axle extension member (8) preferably respectively on two axle extension members (8) which are able to be moved in step, of parallel axles (5 and 6) for tilting movement about a bolt (31) running in the longitudinal direction of the vehicle.

5. The excavator as claimed in claim 4, characterized in that the axle extension members (8) engaging each one respective double wheel suspension means (30) are provided with a respective rack (38) and are drivingly connected with each other as regards pairs of tracks by a synchronizing axle (36) bearing gear wheels (38) cooperating with the rack, there being at least one driving device (34 and, respectively, 35) associated with the axle (36).

6. The excavator as claimed in at least one of the preceding claims, characterized in that at least two of the preferably rubber tired wheel (3 and 4), and preferably two diagonally oppositely placed wheel (3 and 4), are provided with drive devices (27), which are mounted on the latter wheel or, respectively, on the associated wheel suspension means (10 and, respectively, 30), and are preferably in the form of hydraulic motors.

7. The excavator as claimed in any one of the preceding claims 4 through 6, characterized in that the double wheel suspension means (30) respectively mounting two wheel (3 and 4) are in the form of box girders, in which respectively a transmission drive (32) is mounted, which cooperates with a drive device (27), is in the form of chain drive and connects the two associated wheels (3 and 4) drivingly with each other.

8. The excavator as claimed in any one of the preceding claims 2 through 7, characterized in that mutually oppositely positioned axle extension members (8) are able to be slid by at least one piston and cylinder unit (11 and 12) which is preferably arranged in the associated axle (5 and 6).

9. The excavator as claimed in any one of the preceding claims, characterized in that the erection movement of the wheels (3 and 4) is limited by at least one abutment or preferably two abutments (14 and, respectively, 33), which is on the wheel suspension side and is able to be brought into engagement with a counter-abutment (16 and, respectively, 28) on the chassis or, respectively, the axle.

10. The excavator as claimed in any one of the preceding claims, characterized in that at least one roller secured to the chassis is associated with each wheel suspension (10 and, respectively, 30), and at least one associated wheel (3 and, respectively, 4) or, respectively, an abutment (14) secured to the wheel suspension runs on the roller during erection.

11. The excavator as claimed in any one of the preceding claims, characterized in that at least one axle (6) is mounted on the chassis (2) so that it is able to tilt about a bolt (26) running in the longitudinal direction of the vehicle and in that preferably at least one tilting axle (6) is able to be locked by means of a preferably hydraulic locking means.

12. The excavator as claimed in any one of the preceding claims characterized in that the axis (bolt 9 or, respectively, 31) of tilting of the wheels (3 and 4) or, respectively, the wheel suspensions (10 and 30) mounting same is lower down than the center point of the wheel and has a ground clearance, which is approximately equal to the distance between the outer sides of the wheels (3 and 4), which in the tilted condition come into engagement with the ground, and the axis of tilt so that the chassis (2) has approximately the same horizontal level in the tilted and untilted condition of the wheels (3 and 4).

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