GB2611078A

GB2611078A - Boom assembly

Info

Publication number: GB2611078A
Application number: GB2113745.0A
Authority: GB
Inventors: Kemble Paul; Richard Cawdery Andrew; Lee Gorman Corey
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2021-09-27
Filing date: 2021-09-27
Publication date: 2023-03-29
Anticipated expiration: 2041-09-27
Also published as: WO2023049428A1; GB2611078B; JP2024533582A; CN117940635A; EP4409074A1; GB202113745D0

Abstract

An assembly comprising a boom 14 with an actuator attachment point (50, fig.2) and a bifurcated portion 26 comprising two legs 27, 28 extending between the actuator attachment point and a lower end (22, fig.5), connected to a mount 12 about a mount-boom pivot (24, fig.4). A linear actuator 16 is pivotally connected to the mount about a mount-actuator pivot 25 and is pivotably connected to the boom at the actuator attachment point. The linear actuator is connected between the boom and the mount in a plane normal to an axis of rotation of the boom about the mount-actuator pivot, wherein the plane extends between the two legs of the boom. Bifurcation provides space to mount the linear actuator and may increase a movement arc of the boom. Mounting the actuator between the bifurcated legs reduces torsional forces.

Description

Boom assembly

Field of the disclosure

The present disclosure relates to a machine comprising a boom and actuators for controlling the boom. In particular, the present disclosure relates to a boom assembly.

Background

Machines, such as excavators, mini-excavators, backhoes, and the like, may comprise a boom which is attached to the machine chassis at a pivot point. Linear actuators, typically hydraulic linear actuators, are connected between the boom and the chassis in order to control the boom position.

US 3,902,295 A discloses an excavator boom for an excavator. The boom is pivotably connected to the chassis at a pivot point. A pair of linear hydraulic actuators are pivotably each connected to an apex of the boom on opposing sides of the boom. As such, the boom of US 3,902,295 A is located between the pair of hydraulic linear actuators.

US 3,376,984 A discloses a typical arrangement for a boom and a pair of hydraulic linear actuators for a backhoe. In US 3,376,984 A, the boom is pivotably connected to a chassis at a pivot point. A pair of hydraulic linear actuators are connected between the chassis and the boom at either end of the pivot. As such, the boom of US 3,376,984 A is located between the pair of hydraulic linear actuators.

US 4,074,821 B discloses an arrangement for a backhoe wherein the boom comprises a pair of transversely spaced apart boom sections, each boom section pivotably connected to the chassis. A single boom hydraulic linear actuator is then mounted between the boom 30 sections.

Against this background, the present disclosure seeks to provide an improved boom assembly, or at least a commercially useful alternative thereto.

Summary

According to a first aspect of the disclosure, a boom assembly for a machine is provided. The boom assembly comprises a mount, a boom, and a linear actuator. The boom comprises an upper end configured to be connected to an arm, a lower end that is pivotably connected to the mount about a mount-boom pivot, an actuator attachment point located between the upper end and the lower end of the boom, and a bifurcated portion of the boom comprising two legs. The bifurcated portion extends between the actuator attachment point and the lower end of the boom. The linear actuator comprises a first end that is pivotably connected to the mount about a mount-actuator pivot, and an opposing second end that is pivotably connected to the boom at the actuator attachment point. The linear actuator is connected between the boom and the mount in a plane normal to an axis of rotation of the boom about the mount-actuator pivot, wherein the plane extends between the two legs of the boom.

The boom assembly of the first aspect provides a boom having a bifurcated portion. The bifurcated portion provides space for the linear actuator to be mounted to the boom and mount. Mounting the linear actuator between the two legs of the bifurcated portion of the boom reduces the torsional forces acting on the boom with respect to mounting the linear actuator at one side of a non-bifurcated boom.

The bifurcation in the boom may also allow the linear actuator to move between the two legs of the boom during movement of the boom. As such, the bifurcated portion of the boom may be configured to allow the actuator to pass between the two legs during at least a portion of the movement arc of the boom as it pivots about the mount. As such, the boom assembly of the first aspect may provide for an increased movement arc of the boom with respect to the mount.

In some embodiments, the linear actuator may be a hydraulic linear actuator or an electromechanical linear actuator. The bifurcated portion of the boom defines a region in which the packaging for the linear actuator may extend/be located during the movement range of the boom assembly (i.e. as the boom is raised or lowered with respect to the mount). For some linear actuators, in particular electromechanical linear actuators, the packaging of the linear actuator may be relatively large in diameter relative to the actuated piston rod. The bifurcated portion of the boom may define a region to accommodate the 3 -increased packaging size of an electromechanical linear actuator throughout the range of motion of the boom assembly.

In some embodiments, the mount may be provided as a chassis, or at least part of a chassis. The chassis may form part of a machine and the like. That is to say, in some embodiments the boom and the linear actuator may each be pivotably connected to a chassis of a machine. In other embodiments, the mount may provide an intermediate connection between the boom and a chassis. Similarly the mount may provide an intermediate connection between the linear actuator and the chassis.

According to a second aspect of the disclosure, a machine is provided. The machine of the second aspect may incorporate the boom assembly of the first aspect. For example, the machine of the second aspect may be an excavator, a mini-excavator, a backhoe and the like.

Brief description of the figures

By way of example only, embodiments according to the present disclosure are now described with reference to the following figures in which: -Fig. 1 shows an isometric view of an excavator comprising a boom assembly

according to a first embodiment of the disclosure;

Fig. 2 shows a further isometric view of an excavator comprising a boom assembly according to a first embodiment of the disclosure; - Fig. 3 shows a side view of an excavator comprising a boom assembly

according to a first embodiment of the disclosure;

Fig. 4 shows a front view of an excavator comprising a boom assembly according to a first embodiment of the disclosure; Fig. 5 shows an isometric view of a boom of the first embodiment; - Fig. 6 shows a detailed isometric view of the boom assembly of the first embodiment' - Fig. 7 shows an isometric view of an excavator comprising a boom assembly according to a second embodiment of the disclosure; Fig. 8 shows a further isometric view of an excavator comprising a boom assembly according to a second embodiment of the disclosure; 4 - - Fig. 9 shows an isometric view of an excavator comprising a boom assembly according to a third embodiment of the disclosure; - Fig. 10 shows a detailed view of the boom of the third embodiment; - Fig. 11 shows a detailed view of the boom assembly of the third embodiment; -Fig. 12 shows an isometric view of a mini excavator comprising a boom assembly according to a fourth embodiment of the disclosure; Fig. 13 shows a side view of a mini excavator comprising a boom assembly according to a fourth embodiment of the disclosure; - Fig. 14 shows a detailed view of a mini excavator comprising a boom assembly according to a fourth embodiment of the disclosure; Fig. 15 shows a detailed view of a boom of the fourth embodiment; - Fig. 16 shows a detailed view of boom assembly according to a fifth embodiment of the disclosure; Fig. 17 shows a detailed view of a boom according to a sixth embodiment of the

disclosure;

- Fig. 18 shows a detailed view of a boom according to a sixth embodiment of the disclosure; and - Fig. 19 shows an isometric view of an excavator comprising a boom assembly according to a sixth embodiment of the disclosure.

Detailed description

According to embodiments of this disclosure, a boom assembly 10 is provided. According to embodiments of this disclosure, the boom assembly 10 may be provided as part of a 25 machine.

For example, Fig. 1 shows a diagram of an excavator 1 comprising a boom assembly 10 according to a first embodiment of the disclosure. As shown in Fig. 1, the boom assembly 10 comprises a mount 12, a boom 14, and an actuator 16. In the embodiment of Fig. 1, the mount 12 is provided by the chassis of the excavator 1. Fig. 1 shows an isometric front view of the excavator 1, while Fig. 2 shows an isometric rear view of the excavator 1. Fig. 3 shows a side view of the excavator 1, while Fig. 4 shows a front view of the excavator 1.

Fig. 5 shows a detailed view of the boom 14 of the first embodiment. The boom 14 of the excavator 1 has an upper end 20 and a lower end 22. The boom 14 of Fig. 5 may have an

-

upper section 21 extending from the upper end 20 to an elbow section 30. The boom 14 may also have a lower section 23 extending from the elbow section 30 to the lower end 22. As shown in the side view of Fig. 3, the lower section 23 may extend from the lower end 22 in a generally linear manner (i.e. along an axis) towards the elbow section 30. The upper section 21 may extend from the upper end 20 in a generally linear manner towards the elbow section 30. The elbow section 30 of the boom 14 may define a bend of the boom 14 such that an obtuse angle of the boom is defined between the upper and lower sections of the boom 21, 23. As such, in a side view, the boom 14 of Fig. 5 may have a similar obtuse angled shape to booms known in the art.

The upper end 20 of the boom 14 is configured to be connected to an arm 18. In the embodiment of Fig. 1 the upper end 20 is connected to the arm 18 by a pivotable connection. The arm 18 may provide an attachment point 19 for a work tool (not shown) at an opposing end of the arm 18 to the pivotable connection to the boom 14. The work tool may, for example be a bucket or the like. The rotational position of the arm 18 relative to the boom 14 may be controlled by an arm actuator 40. The arm actuator 40 may be connected between the arm 18 and the boom 14. The arm actuator 40 may be a linear actuator of a similar type to the linear actuator 16 of the boom assembly 10.

The lower end 22 of the boom 14 is pivotably connected to the mount 12 at a mount-boom pivot 24. The boom 14 is configured to rotate about the mount-boom pivot 24. In the embodiment of Fig. 1, the mount-boom pivot 24 may extend along a first axis such that the boom rotates in a plane orthogonal to the first axis. In the embodiment of Fig. 1, the first axis may extend in a generally horizontal direction such that the boom 14 rotates about the mount-boom pivot 24 in a generally vertical plane.

As shown in Fig. 5, the boom 14 comprises a bifurcated portion 26. The bifurcated portion 26 extends between the lower end 22 of the boom14 and the upper end 20 of the boom. In the embodiment of Fig. 5, the bifurcated portion 26 also extends between the lower end of the boom 14 and an actuator attachment point 50. In the embodiment of Fig. 5, the bifurcated portion 26 may extend along the boom 14 from the lower end 22 towards the upper end of the boom 14 beyond the actuator attachment point 50.

The bifurcated portion 26 comprises two legs 27, 28. As shown in Fig. 4, each leg 27, 28 extends from the lower end of the boom 22 As such, an end of each leg 27, 28 is 6 -pivotably connected to the mount 12. The two legs 27, 28 are spaced apart to define a void region between the two legs 27, 28. The void region between the two legs 27, 28 may be provided to accommodate at least a portion of the linear actuator 16 during at least a portion of the movement arc of the boom assembly 10. That is to say, the linear actuator 16 may move between the two legs 27, 28 as the boom 14 rotates about the mount-boom pivot 24.

Towards the upper end 20 of the boom 14, the two legs 27, 28 of the boom 14 join together. As such, the bifurcated portion 26 may extend only partially along the length of the boom. In the embodiment of Figs. 1-5, the two legs 27, 28 join together at the elbow portion 30 of the boom. As such, the boom 14 including the bifurcated portion 26 defines a fork shape. That is to say, the boom 14 has a forked lower end comprising two legs 26, 27.

As shown in Fig. 4, an external width of the bifurcated portion 26 of the boom in a direction of the axis of rotation of the boom is greater than a width of the upper end 20 of the boom 14 in the direction of the axis of rotation of the boom 14. That is to say, the legs 27, 28 of the boom 14 are spaced apart such that they are wider (in a direction of the axis of rotation of the boom, which is a horizontal direction in Fig. 4) than the upper end of the boom 20. As shown in Fig. 4, the boom 14 widens at the elbow section 30 to accommodate the change in width of the boom. By widening the bifurcated section 26 of the boom 14, the legs 27, 28 may be provided with increased width, thereby increasing their torsional stiffness, whilst also providing a suitably wide void to accommodate the linear actuator 16.

Fig. 5 shows a partial cross-section through one of the legs 27 to show the internal structure of the leg 27. As shown in Fig. 5. each leg 27,28 of the bifurcated portion 26 may be formed from a box section. The box section structure of each leg 27, 28 extends along a length of the boom 14 between the lower end 22 and the elbow section 30. The box section of each leg 27, 28 provides torsional stiffness for the boom 14.

The boom 14 also includes the actuator attachment point 50. The actuator attachment point 50 provides point on the boom 14 where the linear actuator 16 is pivotably connected to the boom 14. Fig. 6 provides a detailed view of the first embodiment showing the linear actuator 16 pivotably connected to the boom 14 at the actuator attachment point 50. 7 -

In the embodiment of Fig. 1, the two legs 27, 28 of the bifurcated portion 26 may extend along the boom at least: 50, 60, 70, or 80 % of the distance along the boom 14 between the mount-boom pivot 24 at the lower end of the boom 22 and the actuator attachment point 50. In some embodiments, the bifurcated portion 26 may extend along all of the distance between the mount-boom pivot 24 at the lower end of the boom 22 and the actuator attachment point 50, for example as shown in Fig. 1.

In the first embodiment, the actuator attachment point 50 may be located between the legs 27, 28 of the bifurcated portion 26, for example as shown in Figs. 2, 4, and 6 of the first embodiment. In other embodiments, as discussed in more detail below, the actuator attachment point 50 may be provided in other locations of the boom 14.

The linear actuator 16 is provided to control/drive the rotational position of the boom 14 relative to the mount 12. Accordingly, a first end 60 of the linear actuator 16 is pivotably connected to the mount 12 about a mount-actuator pivot 25. At an opposite end of the linear actuator 16, a second end 62 is pivotably connected to the boom 14 at the actuator attachment point 50. The linear actuator 16 is configured to provide a motive force in a linear direction in order to drive the rotational position of the boom 14.

The linear actuator 16 may be a hydraulic linear actuator or an electromechanical linear actuator. In the first embodiment, the linear actuator is an electromechanical linear actuator is provided, but a hydraulic linear actuator would also be suitable. The electromechanical linear actuator shown in Fig. 1 comprises a housing 64. The housing 64 houses the power electronics and motor used to generate the linear motion of the linear actuator 16. While the shape and size of the housing 64 depends on the design of the specific linear actuator 16, it will be appreciated that hydraulic linear actuators do not have the same housing requirements. That is to say, the hydraulic fluid pump used to drive a hydraulic linear actuator can be housed at a remote location away from the boom 14. The boom assembly 10 shown in Fig. 1 can accommodate the housing 64 of the electromechanical linear actuator through the provision of the void between the legs 27, 28 of the bifurcated portion 26 In the first embodiment, only one linear actuator 16 may be connected between the mount 12 and the boom 14 in order to control/drive the rotational position of the boom 14 relative to the mount 12. As such, the first embodiment provides a boom assembly 10 which can be 8 -driven by a single linear actuator 16, rather than a plurality of linear actuators. By mounting the linear actuator 16 in a plane extending between the legs 27, 28, the boom 14 has improved torsional rigidity.

The linear actuator 16 is pivotably connected between the mount 12 and boom 14 in a plane normal to an axis of rotation of the boom about the mount-actuator pivot 25, wherein the plane extends between the two legs of the of the boom. As shown in Fig. 1, at least a portion of the linear actuator 16 extends between the legs 26, 27 of the boom in the void provided by the bifurcated portion 26. Such a bifurcated portion allows a linear actuator 16 to be accommodated by the boom 14 in a generally central position (between the legs 27, 28) whilst allowing the boom 14 to maintain a full range of rotational movement.

In the first embodiment, as shown in Fig. 4, the mount-actuator pivot 25 may be provided below the mount-boom pivot 24. As such, when the linear actuator 16 is contracted, the upper end of the boom 20 is lowered relative to the mount 12. In other embodiments, the relative positions of the mount-boom pivot 24 and the mount-actuator pivot 25 may be different.

In some embodiments, a stiffening member 70 may be provided between the two legs 27, 28 of the bifurcated portion 26 to partially close a region of the bifurcated portion 26 between the two legs towards the lower end of the boom 22. As such, the lower section 23 of the boom 14 may have a whistle shape, wherein the bifurcated section 26 provides an opening between the two legs 27, 28 to accommodate the linear actuator. The stiffening member 70 is provided on a top surface of the legs 27, 28 to provide additional torsional stiffness to the legs 27, 28. As shown in Fig. 4, the box sections of the legs 27, 28 extend between the elbow section 30 and the lower end 22 of the boom below the stiffening member 70.

The stiffening member 70 may close the bifurcated portion 26 along at least 20 % of the length of the bifurcated portion in order to provide a suitable stiffening effect. The stiffening member may close the bifurcated portion along no more than 80 % of the length of the bifurcated portion 26 in order to provide a suitable space to accommodate the linear actuator 16. 9 -

In the embodiment of Fig. 4, the stiffening member 70 may comprise a plate. As such, the stiffening member 70 comprises a plate which extends across the void region of the bifurcated portion 26 between the two legs 27, 28. In other embodiments, the stiffening member 70 may comprise other forms/shapes. For example, in some embodiments, the stiffening member 70 may comprise a tube, or box section, running axially, between the legs 27, 28 (i.e. a central axis of the tube extends in a generally transverse direction to the legs 27, 28).

It will be appreciated that the first embodiment discussed above is only one possible example of a boom assembly 10 according to this disclosure. Various modifications and alternatives to the first embodiment discussed above will be apparent to the skilled person from the following discussion of further embodiments of this disclosure.

According to a second embodiment of the disclosure, an excavator 2 is provided. The excavator 2 is similar to the excavator of the first embodiment in that it comprises a boom assembly 10. Fig. 7 shows a rear isometric view of the excavator 2 of the second embodiment. Fig. 8 shows a front isometric view of the excavator 2 of the second embodiment.

The boom assembly 10 of the second embodiment has a generally similar construction to the first embodiment. The boom assembly of the second embodiment does not include a stiffening member 70 that partially closes a region of the bifurcated portion. As such, each of the two legs 27, 28 of the bifurcated portion extend from the elbow section 30 to the lower end of the boom 30 in a fork shape.

According to a third embodiment of the disclosure, an excavator 3 is provided. The excavator 3 is different to the first and second embodiment in that the boom assembly 10 may comprise a hydraulic linear actuator 80 to drive the boom 14. Fig. 9 shows a front isometric view of the excavator 3. Fig. 10 shows a detailed view of the boom 14. Fig. 11 shows a detailed view of the boom 14 and the mount (chassis) 12 of the excavator 3.

Another difference to the first and second embodiments is that in the third embodiment the mount-actuator pivot 25 is provided above the mount-boom pivot 24. That is to say, at the mount 12 the linear actuator 80 is connected above the boom 14. Consequently, lowering the upper end of the boom 20 causes the linear actuator 80 to extend. As such, it will be -10 -appreciated that boom assemblies 10 according to embodiments of this disclosure may be provided with different arrangements of the mount-boom pivot 24 and the mount-actuator pivot 25. The relative arrangement of the mount-boom pivot 24 and the mount-actuator pivot 25 is shown in Fig. 9.

In addition to varying the relative positions of the mount-boom pivot 24 and the mount-actuator pivot 25, the position of the actuator attachment point 50 may also be varied according to embodiments of the disclosure. For example, as shown in Fig. 10, according to the third embodiment of the disclosure the actuator attachment point 50 may be provided outside of the region between the legs 27, 28 of the bifurcated potion. As shown in Fig. 10, the pivot connection between the linear actuator 80 and the actuator attachment point 50 is provided above, or on, an upper surface 81 of the boom 14. It will be appreciated that the linear actuator 80 of the third embodiment is connected between the boom 14 and the mount 12 in a plane normal to an axis of rotation of the boom 14 about the mount-actuator pivot 25, wherein the plane extends between the two legs 27,28 of the of the boom 14. As such, the boom assembly of the third embodiment can still accommodate the at least a portion of the linear actuator between the legs 27, 28 of the bifurcated portion 26 during at least a portion of its rotational movement.

Fig. 11 shows a detailed view of the actuator 80 connected between the mount 12 and the boom 14. Where the actuator attachment point 50 of the first and second embodiments were located between the legs of the bifurcated portion 26, the actuator attachment point 50 of the third embodiment is offset towards the upper surface 81 of the boom assembly. That is to say, the actuator attachment point 50 may be provided at an axial point along the boom 14 (from the lower end 22 towards the upper end 20) between the two legs 27, 28 (i.e. at an axial point along the bifurcated portion 26). While the actuator attachment point 50 may be provided, axially, within the bifurcated portion 26, the actuator attachment point 50 may be located at a point that is not between the two legs 27, 28. For example, as shown in Figs. 10 and 11, the actuator attachment point 50 is provided above an upper surface 81 of the two legs. A flange 82, or similar member, may be used to locate the actuator attachment point 50 in the desired location.

According to a fourth embodiment, a mini-excavator 4 is provided. Fig. 12 shows an isometric view of the mini-excavator 4 of the fourth embodiment. Fig. 13 shows a side view of the mini-excavator 4 of the fourth embodiment. Fig. 14 shows a detailed view of the boom assembly 10 of the mini-excavator 4 of the fourth embodiment. Fig. 15 shows a detailed view of the boom 14 of the mini-excavator 4 of the fourth embodiment.

It will be appreciated from the fourth embodiment that the boom assembly 10 of embodiments of this disclosure may be used on variety of machines. The boom 14 of the fourth embodiment has a forked shape similar to the boom 14 of the second and third embodiments. The boom 14 and actuator 16 of the fourth embodiment are mounted to the mount 12 in a similar arrangement to the third embodiment. It will be appreciated that in other embodiments, a mini-excavator 4 may be provided with a mounting arrangement similar to the first and second embodiments. The boom 14 may also then be provided with a stiffening member similar to the first embodiment.

The mini-excavator 4 includes a mount 12 to which the boom 14 and the linear actuator 16 are connected which is not the chassis of the machine. Rather, in the mini-excavator 4 the mount 12 provides an intermediate part between the boom 14 and the chassis 90 of the mini-excavator 4. The mount 12 of the mini-excavator may be configured to rotate the entire boom assembly 10 about a vertical axis relative to the chassis 90 of the mini-excavator 90.

The mini-excavator 4 shown in Figs. 12, 13, and 14 is provided with an electromechanical linear actuator 16. As such, it will be appreciated that the boom assembly of this disclosure may also be used to accommodate electromechanical linear actuator of a variety of different sizes on a range of different sized machines.

Fig. 15 shows a detailed view of the boom 14 of the fourth embodiment. It will be appreciated from Figs. 14 and 15 that the actuator attachment point 50 is located on the elbow section 30 of the boom 14. As such, in the fourth embodiment the bifurcated portion 26 of the boom may not extend the entire axial distance to the actuator attachment point 50. It will be appreciated from the embodiments of the disclosure that the extent to which the bifurcated portion 26 extends along the boom 14 towards the actuator attachment point 50, and the location of the actuator attachment point 50 will depend on the size of the linear actuator 16 to be accommodated and the relative positions of the mount-boom pivot 24 and the mount-actuator pivot 25.

-12 -Fig. 16 shows a detailed view of a boom assembly according to a fifth embodiment of the disclosure. As shown in Fig. 16, a mini-excavator 5 is provided. The mini-excavator 5 is similar to the mini-excavator of the fourth embodiment, wherein a hydraulic actuator 80 is provided in place of an electromechanical linear actuator.

According to the first through fifth embodiments of the disclosure, the bifurcated portion 26 of the boom 14 may extend from the elbow section 30 to the lower end of the boom 14 such that two mount-boom pivot 24 connections are provided at the lower end 20, one for each leg 27, 28.

According to a sixth embodiment of the disclosure, a boom assembly 10 may be provided in which the bifurcated portion 26 may not extend completely to the lower end 22 of the boom 14. That is to say, the two legs 27, 28 join together at a lower portion 29 of the boom 14. An example of such a boom 14 is shown in Figs. 17 and 18. An excavator 6 according to the sixth embodiment is shown in Fig. 19.

As such, rather than a forked shape, or a whistle shape, the lower section of the boom 23 forms an 0-shape. In contrast to the whistle shaped embodiment where the box sections of the two legs do not meet towards the lower end 22, in the embodiment of Fig. 17, the box section of the two legs 27, 28 join at together at the elbow section 30 and at the lower section 29.

As shown in Fig. 19, the excavator 6 may be provided with a boom assembly 10 according to the sixth embodiment. In the sixth embodiment, the mount-boom pivot 24 may be provided above the mount-actuator pivot 25, similar to the first and second embodiments. It will be appreciated that the positions of the mount-boom and the mount-actuator pivot 25 may be reversed, similar to the third embodiment. Further, it will be appreciated that a mini-excavator may be provided with a boom assembly 10 having an 0-shaped bifurcated portion 26.

Industrial applicability

According to embodiments of this disclosure, a boom assembly 10 is provided. The boom assembly 10 may be provided as part of a machine. For example, boom assemblies -13 -according to this disclosure may be provided as part of a backhoe, an excavator, or a mini-excavator.

In some embodiments, the linear actuator may be a hydraulic linear actuator or an electromechanical linear actuator. The bifurcated portion of the boom defines a region in which the packaging for the linear actuator may extend/be located during the movement range of the boom assembly (i.e. as the boom is raised or lowered with respect to the mount). For some linear actuators, in particular electromechanical linear actuators, the packaging of the linear actuator may be relatively large in diameter relative to the actuated piston rod. The bifurcated portion of the boom may define a region to accommodate the increased packaging size of an electromechanical linear actuator throughout the range of motion of the boom assembly.

Claims

-14 -CLAIMS: 1. A boom assembly for a machine, the boom assembly comprising a mount, a boom, and a linear actuator, the boom comprising: an upper end configured to be connected to an arm; a lower end that is pivotably connected to the mount about a mount-boom pivot; an actuator attachment point located between the upper end and the lower end of the boom; and a bifurcated portion of the boom comprising two legs, the bifurcated portion extending between the actuator attachment point and the lower end of the boom, and the linear actuator comprising: a first end that is pivotably connected to the mount about a mount-actuator pivot; and an opposing second end that is pivotably connected to the boom at the actuator attachment point, wherein the linear actuator is connected between the boom and the mount in a plane normal to an axis of rotation of the boom about the mount-actuator pivot, wherein the plane extends between the two legs of the of the boom.
2. A boom assembly according to claim 1, wherein an external width of the bifurcated portion of the boom in a direction of the axis of rotation of the boom is greater than a width of the upper end of the boom in the direction of the axis of rotation of the boom.
3. A boom assembly according to claim 1 or claim 2, wherein the linear actuator is connected between the mount and the boom such that the linear actuator extends between the two legs of the bifurcated portion of the boom.
4. A boom assembly according to any preceding claim, wherein the mount-actuator pivot is provided below the mount-boom pivot such that lowering the upper end of the boom causes the linear actuator to contract.
-15 - 5. A boom assembly according to claim 1 or claim 2, wherein the mount-actuator pivot is provided above the mount-boom pivot such that lowering the upper end of the boom causes the linear actuator to extend.
6. A boom assembly according to any preceding claim, wherein the two legs of the bifurcated portion of the boom extend along the boom at least: 50, 60, 70, or 80 % of the distance along the boom between the mount-boom pivot and the actuator attachment point.
7. A boom assembly according to any preceding claim, wherein a stiffening member is provided between the two legs to partially close a region of the bifurcated portion between the two legs towards the lower end of the boom.
8. A boom assembly according to any preceding claim, wherein only one linear actuator configured to control the rotational position of the boom is connected between the mount and the boom
9. A boom assembly according to any preceding claim, wherein the linear actuator is a hydraulic linear actuator or an electromechanical linear actuator.
10. A boom assembly according to any preceding claim, wherein each leg of the bifurcated portion comprises a box section extending along the boom
11. A boom assembly according to any preceding claim, wherein the two legs of the bifurcated portion of the boom extends along the boom beyond the actuator attachment point such that the actuator attachment point is provided between the two legs of the bifurcated portion.
12. A boom assembly according to any of claims 1 to 10, wherein the two legs of the bifurcated portion of the boom join together at a point along the boom between the bifurcated portion of the boom and the actuator attachment point.-16 -
13. A boom assembly according to any preceding claim, wherein the two legs of the bifurcated portion of the boom extend to the mount-boom pivot such that each leg is pivotably connected to the mount.
14. A boom assembly according to any of claims 1 to 12, wherein the two legs of the bifurcated portion of the boom join at a point along the boom towards the lower end such that the lower end of the boom is pivotably connected to the mount-boom pivot by a single pivotable connection.
15. A machine comprising the boom assembly of any of claims 1 to 14.