EP4108835A1 - Mini-excavator with adjustable boom - Google Patents

Abstract

The invention relates to a mini excavator with an undercarriage (1), an upper carriage (2), a multi-part extension arm (3) attached to the upper carriage (2) so that it can be raised and pivoted, the multi-part extension arm (3) being attached from the attachment point (21) on the upper carriage (2) seen, has a basic boom arm (31) with associated first hydraulic cylinder (41), an adjustable boom arm (32) with associated second hydraulic cylinder (42) and a stick (33) with associated third hydraulic cylinder (43), articulated with three pivot joints (51, 52, 53) are connected to one another and are designed to be adjustable relative to one another by means of the hydraulic cylinders (41, 42, 43), characterized in that the main extension arm (31) is a hollow profile in which the second hydraulic cylinder (42) is accommodated.

Description

The invention relates to a mini excavator with an undercarriage, an upper carriage, a multi-part extension arm attached to the upper carriage such that it can be raised and pivoted, the multi-part extension arm seen from the attachment point on the upper carriage, a basic extension arm with an associated first hydraulic cylinder, an adjustable extension arm with an associated second hydraulic cylinder, and a stick having an associated third hydraulic cylinder, which are connected to one another in an articulated manner by means of three rotary joints and are designed to be adjustable in relation to one another by means of the hydraulic cylinder.

Hydraulic excavators are known in a wide variety of configurations in the prior art. For example, the DE 20 2008 012 344 U1 a small hydraulic excavator that has a boom with an adjustable boom arm, i.e. another possible kink point in the boom, in order to increase the reach of the boom and also to be able to carry out special tasks when excavating.

A method for estimating the position and orientation of several mobile modules of a common system is in DE 10 2019 201 091 A1 described, wherein therein a corresponding hydraulic excavator with an adjustable boom in 1 is shown.

the GB 2 031 843 A shows an excavator boom having a one-piece boom with a stick pivoted thereon. The pivoting is effected by means of hydraulic cylinders arranged on the outside.

Furthermore, from the US 4,686,782A an excavator boom with a one-piece boom arm and a stick pivotally attached to it, in which the hydraulic cylinders required for actuating the respective boom components, namely raising and lowering the boom arm, adjusting the boom stick and adjusting the excavator shovel, are each arranged in the boom or stick. However, it is not an adjustable boom, so the boom is inherently rigid.

A similar excavator boom is from the US 3,220,578A famous. This is also a normal excavator boom, i.e. no adjustable boom. A handle for holding the excavator shovel is attached to the inherently rigid, one-piece cantilever arm so as to be pivotable about an axis. Here, too, the hydraulic cylinder provided for adjusting the stick relative to the extension arm is arranged in the extension arm, which obviously has a rectangular cross section.

In the case of mini excavators, i.e. hydraulic excavators with a maximum total weight of 5 t, an adjustable boom, i.e. a boom with an additional kink point, is not common, since the mechanical complexity, the control complexity and the total vehicle weight usually do not allow such equipment. Furthermore, in mini excavators, due to the cramped conditions and thus short visibility distances, a boom with various adjustment options and associated hydraulic cylinders is critical to handle and, in particular, such extensions on the boom harbor the risk of excessively restricting the view of the construction site. Furthermore, precisely on narrow construction sites, where mini excavators are preferably used, there is a risk that the sensitive hydraulic actuating elements and their supply lines could be damaged if they come into contact with building structures, etc., and/or that hydraulic fluid could leak out.

The object of the invention is therefore to specify a mini excavator which has an adjustable boom and at the same time shows a high level of safety in operation and use.

This object is achieved with a mini excavator according to claim 1. If the basic boom is a hollow profile in which the second hydraulic cylinder is accommodated, the second hydraulic cylinder for adjusting the adjustable boom relative to the basic boom is housed in the hollow basic boom in a protected manner. As a result, this second hydraulic cylinder does not restrict the view of the construction site, since only the profile of the basic boom arm that is otherwise required is present. It must be taken into account that previously the hydraulic cylinders were arranged on the outside of the boom, either in front or below the boom or behind or above the boom with one hydraulic cylinder each or even on the side of the boom with two hydraulic cylinders arranged on both sides. Since these attachments always have to be arranged close to the attachment point of the multi-part boom arm on the superstructure and thus close to the operator's cab of the mini excavator, these attachments limit the view of the excavator operator considerably. There is also a considerable risk, particularly when using such mini excavators in confined spaces, that hydraulic lines leading to these cylinders and/or the hydraulic cylinders themselves are damaged, which entails expensive repairs and/or can lead to unwanted environmental pollution.

Due to the fact that the second hydraulic cylinder is fastened with its one eye in the base boom near the starting point of the base boom on the superstructure so that it can rotate about a first support axis that is perpendicular to the longitudinal extension of the base boom and horizontally arranged, the spatially wider and thus also heavier end of the hydraulic cylinder is as close as possible to the superstructure fixed in the basic extension arm.

If the free end of the second hydraulic cylinder is articulated on the adjustable jib arm near the second rotary joint between the basic jib arm and the adjustable jib arm, the second hydraulic cylinder can move the adjustable jib arm over a relatively small adjustment triangle with relatively small tilting and positioning movements of the second hydraulic cylinder in relation to the basic jib arm over a large swivel range of at least 90° or preferably more than 120°.

Accordingly, the free space in the hollow profile is sufficient for the required relative tilting and positioning movements of the second hydraulic cylinder in the main boom if the hollow profile of the main boom has a rectangular cross-section that widens from the starting point on the superstructure to the second swivel joint between the main boom and the adjustable boom.

Due to the fact that the adjustable boom arm is also a hollow profile, in which the third hydraulic cylinder is accommodated, the third hydraulic cylinder can also be accommodated in a protected manner in the interior of the adjustable boom arm designed as a hollow profile. In principle, the same advantages apply here as for the second hydraulic cylinder arranged in the main boom arm. It should also be noted here that although the visibility restrictions caused by externally arranged hydraulic cylinders are relatively less at a greater distance from the driver's cab, the risk of damage to externally arranged hydraulic cylinders on the adjustable boom arm increases significantly.

In order to allow the best possible center of gravity and sufficient freedom of movement for the third hydraulic cylinder, one eye of the third hydraulic cylinder is rotatably mounted in the adjustable boom about a second support axis arranged horizontally and perpendicular to the longitudinal extent of the adjustable boom.

Correspondingly, the free end of the third hydraulic cylinder is preferably articulated on the stick near the third pivot joint between the adjustable boom arm and the stick.

The hollow profile of the adjustable boom arm preferably has a rectangular cross section in order to be able to accommodate the third hydraulic cylinder with a corresponding pivoting movement space in the adjustable boom arm.

If the hydraulic lines for the second hydraulic cylinder are routed within the hollow profile of the main boom, they are protected in the hollow profile of the main boom, which significantly reduces the risk of damage to the hydraulic lines.

Likewise, the hydraulics are better protected when hydraulic supply lines for the third hydraulic cylinder are routed within the hollow profile of the adjustable boom arm.

Due to the fact that further hydraulic supply lines for the implements to be attached to the stick and their adjustment and/or drive elements are guided in the hollow profiles of the basic boom arm and the adjustable boom arm, the further hydraulic supply lines can also be guided inside the hollow profiles in a protected manner.

In a further development, the hydraulic supply lines for the functions of the boom and the attachments to be attached to the stick as well as their adjustment and/or drive elements are routed directly from the superstructure into the hollow profile of the basic boom arm at the attachment point on the superstructure. This prevents hydraulic lines from being exposed on the outside of the boom, which could be damaged from the outside during any work with the mini excavator.

An exemplary embodiment of the invention is described in detail below with reference to the accompanying drawings.

Fig. 1

einen Minibagger mit mehrteiligem Ausleger in einer Seitenansicht und

Fig. 2

den mehrteiligen Ausleger in detaillierter 3D-Ansicht.

It shows:

1

a mini excavator with a multi-part boom in a side view and

2

the multi-part boom in a detailed 3D view.

In 1 a mini excavator is shown in a schematic side view with an undercarriage 1, here with a crawler chassis 11 and an uppercarriage 2 arranged on the undercarriage 1 so that it can rotate about a vertical axis. The superstructure 2 contains the drive unit, the hydraulic supply, the excavator driver's cab and the associated control panel for operation. Furthermore, a starting point 21 is arranged on the superstructure 2, on which a multi-part boom 3 is pivoted about a first pivot joint 51.

The multi-part jib 3 consists of a basic jib arm 31 articulated on the first pivot joint 51, an adjustable jib arm 32 articulated pivotably on a second pivot joint 52 at the free end of the basic jib arm 31, and a stick 33 articulated on the free end of the adjustable jib arm 32 pivotable about a third pivot joint 53. At the free end of the handle 33 are working tools, not shown here, and their adjustment or drive elements, such as an excavator shovel. The details regarding the basic cantilever arm 31 and adjustable cantilever arm 32 are in 2 shown in detail in a spatial view, in which internal or rear components are shown in dashed lines.

A first hydraulic cylinder 41 is clamped in the usual way between the starting point 21 and a corresponding counter bearing at the free end of the basic boom arm 31 for pivoting the basic boom arm 31 at the starting point 21 of the superstructure 2 about the first pivot joint 51 . Thus lies the first hydraulic cylinder 41 in front of the basic boom arm 31, so that its components do not impair the operator's view of the construction site.

A second hydraulic cylinder 42 is arranged in the basic extension arm 31, which is designed as a hollow profile, for pivoting the adjustable extension arm 32 about the second swivel joint 52 at the free end of the basic extension arm 31. In the basic boom arm 31 designed as a hollow profile, a first support axis 34 is arranged perpendicular to the longitudinal extent of the basic boom arm 31 and horizontally, i.e. parallel to the plan plane of the superstructure 2, on which the second hydraulic cylinder 42 is pivotably fixed with its fastening eye 44. The piston rod side of the second hydraulic cylinder 42 is preferably arranged facing away from this support axis 34 and is articulated with its piston rod end 45 on the adjustable boom 32 near the second rotary joint 52 on a lever bearing axis 35 in such a way that an actuating triangle is formed for transmitting the torque required for pivoting the adjustable boom 32. like this in the 1 and 2 is evident.

How further in particular from 2 can be seen, the hollow profile of the basic boom 31 has a rectangular cross-section, which widens from the starting point 21 on the superstructure 2 to the second swivel joint 52 between the basic boom 31 and the adjustable boom 32 . Accordingly, when the second hydraulic cylinder 42 is adjusted, the adjustable extension arm 32 can be pivoted in its full pivoting range, in particular over more than 90°, preferably at least 120°, without the second hydraulic cylinder 42 arranged inside the basic extension arm 31 in the interior of the hollow profile with the walls in touched.

For the driver of the excavator, the view of the working area of the excavator is not restricted by the second hydraulic cylinder 42 arranged on the inside in the base boom arm 31 via the base boom arm profile that is of course required. In addition, the second hydraulic cylinder is 42 protected within the basic cantilever arm 31 arranged. Likewise, the hydraulic supply lines 40, which are in 1 are indicated schematically by small dashed lines, arranged protected in the hollow profile.

For the sake of completeness, in 1 a third hydraulic cylinder 43 is also shown, with which the stick 33 of the multi-part boom 3 is designed to pivot about the third swivel joint 53 at the free end of the adjustable boom 32 . in 1 illustrated embodiment, this third hydraulic cylinder 43, as is usually known, arranged on the outside of the adjustable boom arm 32. In a preferred embodiment, not shown here, the adjustable extension arm 32 is also designed as a hollow profile with a substantially rectangular cross section and this third hydraulic cylinder 43, like the second hydraulic cylinder 42, is arranged in the interior of this hollow profile. This would also result in advantages with regard to the protection of the hydraulic elements on the cantilever arm 3 for this embodiment.

Reference List

1

undercarriage

11

crawler chassis

2

superstructure

21

starting point

3

multi-part boom (arm)

31

basic boom arm

32

adjustable boom arm

33

stalk

34

first support axis

35

lever bearing axle

40

hydraulic line

41

first hydraulic cylinder

42

second hydraulic cylinder

43

third hydraulic cylinder

44

(mounting) eye

45

piston rod end

51

first pivot

52

second pivot

53

third pivot

Claims (12)

Mini excavator with an undercarriage (1), an upper carriage (2), a multi-part extension arm (3) attached to the upper carriage (2) such that it can be raised and pivoted, the multi-part extension arm (3) seen from the attachment point (21) on the upper carriage (2). , a basic boom arm (31) with an associated first hydraulic cylinder (41), an adjustable boom arm (32) with an associated second hydraulic cylinder (42) and a stick (33) with an associated third hydraulic cylinder (43), which are articulated with three rotary joints (51, 52 , 53) connected to one another and designed to be adjustable relative to one another by means of the hydraulic cylinders (41, 42, 43), characterized in that the main extension arm (31) is a hollow profile in which the second hydraulic cylinder (42) is accommodated. Mini excavator according to claim 1, characterized in that in the base boom near the attachment point (21) of the base boom (31) on the superstructure (2) the second hydraulic cylinder (42) with its one eye around a perpendicular to the longitudinal extension of the base boom (31) and arranged horizontally first support axle (34) is rotatably mounted. Mini-excavator according to Claim 2, characterized in that the free end of the second hydraulic cylinder (42) is articulated on the adjustable jib arm (32) near the second pivot joint (52) between the basic jib arm (31) and the adjustable jib arm (32). Mini-excavator according to one of the preceding claims, characterized in that the hollow profile of the basic boom arm (31) has a rectangular cross-section extending from the starting point (21) on Superstructure (2) widens to the second swivel joint (52) between the basic boom arm (31) and the adjustable boom arm (32). Mini-excavator according to one of the preceding claims, characterized in that the adjustable extension arm (32) is also a hollow profile in which the third hydraulic cylinder (43) is accommodated. Mini excavator according to claim 4, characterized in that in the adjustable boom (32) the third hydraulic cylinder (43) is fastened with its one eye so as to be rotatable about a second support axis arranged horizontally and perpendicular to the longitudinal extension of the adjustable boom. Mini-excavator according to Claim 5, characterized in that the free end of the third hydraulic cylinder is articulated on the stick (33) close to the third pivot (53) between the adjustable boom arm (32) and the stick (33). Mini-excavator according to one of the preceding claims, characterized in that the hollow profile of the adjustable extension arm (32) has a rectangular cross-section. Mini-excavator according to one of the preceding claims, characterized in that hydraulic supply lines (40) for the second hydraulic cylinder (42) are routed within the hollow profile of the basic boom arm. Mini excavator according to one of the preceding claims, characterized in that hydraulic supply lines for the third hydraulic cylinder (43) are routed within the hollow profile of the adjustable boom arm (32). Mini-excavator according to one of the preceding claims, characterized in that further hydraulic supply lines (40) for the working implements to be fastened to the stick (33) and their adjustment and/or drive elements are guided in the hollow profiles of the basic boom arm (31) and the adjustable boom arm (32). Mini excavator according to one of the preceding claims, characterized in that the hydraulic supply lines (40) for the functions of the boom (3) and the working implements to be fastened to the stick (33) and their adjustment and/or drive elements at the attachment point (21) on the superstructure ( 2) are routed directly from the superstructure into the hollow profile of the main boom arm (31).

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