EP0376120B1 - Excavator boom - Google Patents

Abstract

An excavator arm with basic boom 12, intermediate boom 14 and shovel stem 16 with digging implement is connected to a support part 86 which can be driven directly or indirectly into rotation about a vertical axis 84. In order to dig trenches with vertical walls outside the longitudinal axis of the vehicle and to achieve an advantageous transport position, the intermediate boom 14 consists of a front part 14a, a rear part 14b and a common rotary joint 20, the most advantageous transport position being achieved by rotating by 180 DEG the front part 14a, about the axis of rotation 22 set vertically, from the extended operational position relative to the rear part 14b.

Description

The invention relates to a three-part excavator arm, which consists of a basic boom, intermediate boom and dipper arm and is connected to the basic boom on an excavator base, the intermediate boom consisting of a front part, a rear part and a common swivel joint, the axis of rotation of which can be adjusted in a vertical course.

The digging device known as 'excavator arm' known excavators or backhoe loaders generally consists of a one-piece mono boom or a two-piece boom (composed of basic boom and intermediate boom), also from the dipper stick and from a digging tool. In the case of rear excavators, the basic boom is connected to a mounting bracket that can be pivoted on both sides of the rear frame around a vertical axis.

From GB-A-2 086 347 a three-part excavator arm is known, in which the intermediate boom consists of a front part, a rear part and a common swivel joint, the axis of rotation of which lies in the vertical pivot plane of the intermediate boom rear part. The basic boom is mounted on a horizontal swivel axis on an excavator base, which in turn is mounted on the superstructure of the Excavator is arranged. With this excavator arm, the axis of the swivel joint of the intermediate boom is held in the vertical position, it is possible to dig trenches running parallel to the direction of travel of the excavator with vertical walls and with a selectable depth of the trench bottom.

The invention has set itself the task of improving an excavator arm of the type mentioned in such a way that it can be folded into a convenient, space-saving position during transportation or when driving the excavator, with which it keeps the vehicle profile low and does not have the side by side the fixed vehicle bodies or vehicle contours specified by the rear mounting frame protrude.

According to the invention, this object is achieved in that the basic boom can be rotated directly or indirectly about a vertical axis, that the front part and the rear part of the intermediate boom can be rotated through 360 ° to one another by means of the common swivel joint, in that these intermediate boom parts are arranged one behind the other along the axis of rotation of the swivel joint, and in that The front part and the rear part can be locked to one another by means of a locking device at least in a rotational position pointing in the same direction from the swivel joint.

In this design, the intermediate boom can be pivoted as a whole in its position relative to the basic boom in its stretched state. Since it consists of two through a common swivel Connected parts exist that can be finally or endlessly rotated relative to each other about the preferably vertically set axis of the swivel joint, the diffraction of the intermediate boom creates the possibility of using the excavator arm to draw trenches with vertical side walls outside the vehicle's longitudinal axis. For this purpose, either the superstructure of the excavator is adjusted by a direction of rotation in the opposite direction corresponding to the diffraction angle, until the front part of the intermediate boom runs parallel to the longitudinal axis of the vehicle. Analogous to the rotation of the uppercarriage, for example in the case of a front loader provided with a backhoe, the basic boom connected to the work vehicle with a holder which can be rotated about a vertical axis is adjusted about the said vertical axis. Any spatial twisting of the dipper stick can be achieved if the axis of the swivel joint is outside the vertical.

In addition to these advantages relating to digging operations, the intermediate boom designed according to the invention ensures that it takes up inexpensive, space-saving positions for transport or when the excavator is traveling on the road, with little construction effort. In order to bring the excavator arm of a backhoe into its transport position, it has previously been customary to move the carriage, which is guided horizontally on the mounting frame and on which the mounting bracket supporting the basic boom can be pivoted about a vertical axis, into a lateral end position and then to move the mounting bracket to the system to pivot sideways on the mounting frame so that the folded excavator arm does not exceed the specified Excavator contours protrude. In the excavator arm according to the invention, there is no need to move the carriage, since the excavator arm reaches the space-saving transport position from a central working position on the mounting frame by folding the extended intermediate boom, namely pivoting the front part by approximately 180 ° to beyond the rear part.

The application of the invention leads to comparable advantages in a mobile excavator with a rotating superstructure, to which the excavator base is firmly attached and the excavator arm by swiveling back the front part in the working position of the extended intermediate boom by about 150 ° in a space provided next to the side driver's cab in one very economical, space-saving and unobstructed view of the transport position.

According to one embodiment of the excavator arm, the front part of the intermediate boom can be arranged above the rear part with an approximately vertical axis of rotation of the swivel joint.

The front part expediently has a greater length and is dimensioned such that an unimpeded rotation of the front part with a vertically downward-pointing dipper stick and a folded digging tool is possible with an approximately vertical course of the basic boom and axis of rotation.

According to an additional feature, the front part of the intermediate boom have an angled shape downwards and thus contribute to a low overall height in the space-saving transport position.

In one embodiment, the swivel joint can be arranged approximately in the rear third of the intermediate boom, so that the front part is approximately twice as long as the rear part and underneath offers space for the compact folding.

For another embodiment of the excavator arm according to the invention it is proposed that the front part of the intermediate boom is shorter than the rear part, and is arranged below the rear part with an approximately vertical axis of rotation of the swivel joint, the swivel joint being arranged approximately in the front third of the total length of the intermediate boom. In this variant, the front part is shortened so far compared to the rear part of the intermediate boom that the front part can be rotated endlessly with the dipper stick and digging tool pointing downwards below the approximately horizontally set rear part.

According to a preferred design, the swivel joint between the front part and the rear part can consist of a swivel ring, while a servo-driven index bolt is provided for locking the swivel joint. To fix the swivel joint, a brake acting on the swivel head or a rotating motor with an automatic brake can be provided in addition or alternatively to the index bolt.

The turntable expediently has cooperating, externally sealed bearing rings attached to opposite connection surfaces on opposite connection surfaces of the front part and rear part of the intermediate boom, and the drive pinion of the rotary motor and the index bolt with its guide can be arranged in the space between the two connection surfaces.

According to a further embodiment of the invention, the axis of rotation of the swivel joint can automatically be held vertically, for example with the aid of a parallelogram linkage which is formed with the inclusion of the basic boom, so that in this case all laterally offset or transverse trenches have vertical side walls and, moreover, automatically the space-saving transport position of the excavator arm is achieved. The one or more links of the parallelogram can be replaced by hydraulic cylinders, which in the retracted or extended end position have the same length as the basic boom and form a parallelogram with this.

• Fig. 1 einen an einen Sockel angeschlossenen dreiteiligen Baggerarm nach der Erfindung in Arbeitsstellung sowie mit unterbrochenen Linien in raumsparender Straßentransportstellung,
• Fig. 2 den Baggerarm in einer Arbeitsstellung mit waagerechtem Grundausleger und mit um 90° geknicktem Zwischenausleger, während unterbrochene Linien den Baggerarm bei gestrecktem Zwischenausleger wiedergeben,
• Fig. 3 in größerer Darstellung eine Drehverbindung zwischen Vorderteil und Hinterteil des Zwischenauslegers im Längsschnitt und mit schematisch eingezeichneter Hydraulikschaltung,
• Fig. 4 einen Baggerarm, bei dem der Antriebszylinder für den Zwischenausleger durch einen Parallelogrammlenker ersetzt ist,
• Fig. 4a den Baggerarm aus Fig. 4 bei waagerechtem Grundausleger und mit einem am Zwischenausleger angreifenden, als Parallelogrammlenker wirksamen Hydraulikzylinder,
• Fig. 5 die Ansicht eines Heckbaggers mit in Transportstellung befindlichem Baggerarm,
• Fig. 5a eine Draufsicht auf die Anordnung nach Fig. 5,
• Fig. 6 die Seitenansicht eines Radbaggers mit einem in Transportstellung zurückgeschwenkten Baggerarm und
• Fig. 7 eine Draufsicht auf den Radbagger nach Fig. 6.

Further details and advantages of the excavator arm according to the invention result from the description of exemplary embodiments with reference to the drawings. Show it:

• 1 is a three-part excavator arm connected to a base according to the invention in the working position and with broken lines in a space-saving road transport position,
• 2 shows the excavator arm in a working position with a horizontal basic boom and with an intermediate boom bent by 90 °, while broken lines represent the excavator arm with the intermediate boom extended,
• 3 is a larger view of a rotary connection between the front part and rear part of the intermediate boom in longitudinal section and with a schematically drawn hydraulic circuit,
• 4 shows an excavator arm in which the drive cylinder for the intermediate boom is replaced by a parallelogram link,
• 4a the excavator arm from FIG. 4 with a horizontal basic boom and with a hydraulic cylinder acting on the intermediate boom and acting as a parallelogram link,
• 5 shows the view of a backhoe with the excavator arm in the transport position,
• 5a is a plan view of the arrangement of FIG. 5,
• Fig. 6 is a side view of a wheel excavator with an excavator arm pivoted back in the transport position and
• 7 is a plan view of the wheel excavator of FIG. 6th

According to FIG. 1, an excavator arm with its basic boom 12 is connected in an articulated manner to a schematically shown excavator base 10, which can be rigidly attached to the rotatable superstructure of a mobile excavator similar to FIG. 6. The basic boom 12 articulated on the base 10 can be pivoted vertically by means of the cylinder 24.

An intermediate boom 14 is articulated to the front end of the basic boom 12 and comprises a front part 14a, a rear part 14b and a common swivel joint 20, the axis of rotation 22 running in or parallel to the vertical pivoting plane of the basic boom 12 and rear part 14b. A dipper arm 16 for a bucket 18 or another digging tool is articulated on the front part 14a of the intermediate boom, which can be pivoted by means of a cylinder 28 supported on the intermediate boom 14, while a drive cylinder 30 is provided on the dipper arm for the working movements of the digging tool 18.

The extended length of the intermediate boom 14 used in normal work is shown in solid lines in FIG. 1, while a space-saving transport position achieved while maintaining the upright base boom 12 is shown with broken lines, in which the front part 14a about the axis 22 of the swivel joint opposite the stretched position is rotated by 180 °. Under the conditions shown, in which the front part and the rear part cover each other, the intermediate boom 14 is in its shortest state, which can be used for the space-saving road transport position of the excavator arm, for example if it is arranged next to the driver's cab of a work vehicle.

2, with the base boom 12 pivoted horizontally, the rear part 14b of the intermediate boom is brought into the stretched state by means of hydraulic cylinders 26, while the front part 14a is pivoted backwards by 90 ° from the drawing plane. As long as the axis of rotation 22 is set vertically, 18 vertical walls can be machined with the excavator bucket or loads can be picked up and deposited laterally. On the left side of FIG. 2, the state of the excavator arm with the intermediate boom 14 stretched is shown with broken lines. The extensive pivoting and working possibilities of this excavator arm also result from the bent end position of the rear part 14b, indicated by broken lines in FIG. 2, including the correspondingly inclined axis of rotation 22.

A swivel joint designed as a rotating ring 32 between the front part and the rear part of the intermediate bracket 14 is formed according to FIG. 3 between the mutually opposite connection surfaces 50, 52 on the front part 14a and on the rear part 14b in that a bearing ring 54 on the upper connection surface 50 and on the lower one Pad 52 a bearing ring 56 is attached, which are connected to each other via balls or similar rolling elements 55. The bearing rings 54, 56 are fastened to the connection surfaces with the aid of screws and with the aid of Sealing sleeves 68 sealed against each other. The upper bearing ring 54 has an internal toothing 58, in which a pinion 60 of the hydraulic rotary motor 36 engages in order to rotate the front part 14a with respect to the rear part 14b of the intermediate boom.

A rotary union 70 for the hydraulic supply to the cylinders 28 and 30 is fastened to the upper connecting surface 50 and projects through an opening in the lower connecting surface 52. The rotary motor 36 and an actuating cylinder 62 for an index bolt 34 are flanged to the lower connecting surface. A piston 64 connected to the index bolt 34 is displaceable in the cylinder 62. The index bolt 34 is biased by a spring 72 into the locking position shown in solid lines, from which it is retracted by means of the hydraulic system against the spring force when the front part 14a of the intermediate boom is to be rotated.

A sequence of positioning openings 66 (not shown) in the upper connecting surface 50 is assigned to the index bolt 34. When the rotary motor 36 is actuated in one or the opposite direction by the parallel circuit 42, the hydraulic circuit ensures that pressure medium is first supplied to the cylinder 62 so that the index bolt moves back and the connecting surface 50 is released for rotation. Depending on the switching position of the control device 44, the pump 48 supplies the changeover valve 46 in the parallel circuit 42 with pressure medium from one or the opposite side.

4 and 4a show the excavator arm in similar working positions as in Fig. 1 and 2, but with the difference that the cylinder 26 of the intermediate boom is replaced by a link 38 which runs parallel to the base boom 12 and is connected to the base 10 . When the cylinder 24 is actuated and the base boom is pivoted, the rear part 14b of the intermediate boom is consequently constantly guided in parallel, so that it also rotates the axis of rotation 22 vertically in the position shown in FIG. 4a holds.

As a variant, it is indicated in FIG. 4 a that the link 38 from FIG. 4 - which can be provided twice in a symmetrical arrangement - is replaced by a hydraulic cylinder 40. In its extended position, the cylinder 40 acts like the handlebar 38, since it then has the same length as this. The resulting position of the axis of rotation 22 when the cylinder 40 is retracted is indicated by broken lines in FIG. 4a.

A practical application example for the excavator arm which can be folded into a narrow space is shown in FIGS. 5 and 5a, where, for example, a rear frame 76 which can be attached to a vehicle is the carrier of an excavator arm according to the invention. In the middle of the rear frame 76 provided with telescopic supports 78, a vertical pivot axis 84 for a mounting bracket 86 is arranged on bearing attachments 80, 82, which, like an excavator base, supports the lower end of the basic boom 12 and the associated pivot cylinder in an articulated manner. The mounting bracket 86 can be pivoted with the excavator arm from the straight line position indicated in FIG. 5a and coinciding with the longitudinal axis of the vehicle to either side for any work application by α = 90 ° or more. In each swivel position of the attachment holder 86, the front part 14a of the intermediate boom and thus also the dipper stick and digging bucket can be adjusted parallel to the longitudinal axis of the vehicle with the help of the swivel joint 20.

In order to achieve the favorable transport position in which the folded excavator arm remains within the lateral boundary lines 74 of the vehicle contour, the front part 14a of the intermediate boom 14 which is extended to the left in FIG. 5 is pivoted back by β = 180 °, as a result of which the length of the intermediate boom 40 considerably reduced, so that in a space-saving folding according to FIG. 5, the attachment bracket 86 and the rear part 14b point to the left, while the front part 14a holds the dipper stick 16 with the digging bucket 18 within the general vehicle contours. The vertical pivot axis 84 remains in the center of the rear frame 76.

6 and 7 illustrate the use of the excavator arm in connection with an excavator base 10, which belongs to an uppercarriage 92 which can be rotated about a vertical axis 88 on the chassis 90 of a mobile excavator. From the uppercarriage 92 set in the direction of travel, the fixed base 10 projects forward into the preferred main excavator position indicated in FIG. 7. Together with the uppercarriage 92, the excavator arm can be pivoted endlessly about the vertical axis 88, the front part 14a of the intermediate boom 14 with dipper stick and digging tool being able to be adjusted in any position of the uppercarriage parallel to the longitudinal direction of the vehicle or else in any position. The preferred transport position is reached in accordance with FIG. 7 in an inclined position of the excavator arm, because the total angle of rotation of the front part 14a from the extended state of the intermediate boom to its transport position is approximately 150 °, the excavator arm being braked and locked to the side next to the driver's cab 94 and inside the lateral vehicle limits remains. The lowest possible overall height of the excavator arm in the transport position is achieved by the downward bending of the front section of the front part 14a.

Claims (11)

1. A three-part excavator arm consisting of a basic boom (12), an intermediate boom (14) and a dipper arm (16) and connected by the basic boom to an excavator base (10), the intermediate boom consisting of a front member (14a), a rear member (14b) and a common rotary joint (20) of which the axis of rotation (22) can be adjusted into a vertical attitude,
characterized in that

- the basic boom (12) can be rotated directly or indirectly about a vertical axis,

- the front member (14a) and the rear member (14b) of the intermediate boom are rotatable about 360° relative to each other due to the fact that these intermediate boom members are arranged one after another along the axis of rotation (22) of the rotary joint (20),

- and in that the front member (14a) and the rear member (14b) can be arrested with respect to each other by a locking means (34) at least into a position pointing in the same direction from the rotary joint (20).

2. Excavator arm defined in claim 1, characterized in that the front member (14a) of the intermediate boom is mounted above the rear member (14b) with the rotational axis (22) of the rotary joint (20) being approximately vertical.

3. Excavator arm defined in claim 2, characterized in that the front member (14a) is longer and of such dimensions that when the basic boom (12) and the axis of rotation (22) are approximately vertical, the front member (14a) together with the dipper arm (16) pointing vertically down and the collapsed excavating implement (18) can be freely rotated.

4. Excavator arm defined in one of the above claims, characterized in that the front member (14a) of the intermediate boom (14) is of downwardly bent form and thereby contributes to a lesser total height of the excavator arm when in the transport position.

5. Excavator arm defined in one of the above claims, characterized in that the rotary joint is mounted approximately in the rear third of the intermediate boom (14).

6. Excavator arm defined in claim 1, characterized in that the front member of the intermediate boom (14) is shorter than the rear member, in that the rotary joint (20) is disposed underneath the rear member, when the axis of rotation substantially extends in vertical direction, and in that the rotary joint is mounted approximately in the front third of the total length of the intermediate boom.

7. Excavator arm defined in one of the above claims, characterized in that the rotary joint between the front member (14a) and the rear member (14b) of the intermediate boom consists of a rotary crown (32) and in that a servo-driven indexing bolt (34) is provided to lock the rotary joint into specific angular positions.

8. Excavator arm defined in one of the above claims, characterized in that a rotary motor (36) and an automatic brake are provided to lock the rotary joint (20).

9. Excavator arm defined in claim 7 or 8, characterized in that the rotary crown comprises cooperating bearing rings (54, 56), sealed to the outside and mounted to opposite connection surfaces (50, 52) at the front and at the rear members of the intermediate boom (14), and in that the drive pinion (60) of the rotary motor (36) and the indexing bolt (34) with its guide are mounted in the gap between the two connection surfaces (50,52).

10. Excavator arm defined in one of the above claims, characterized in that the rear member (14b) of the intermediate boom (14) is kept in a preferred position by at least one guide link (38) parallel to the basic boom (12), the axis of rotation (22) in general being vertical in said preferred position.

11. Excavator arm defined in claim 10, characterized in that the parallelogramm guide link consists of a hydraulic jack (40) the length of which either in its extended or retracted end position being matched to the parallelogramm relationship with the basic boom.

Images