A counterweight adjustment mechanism

Abstract

Disclosed is a reduced tail swing excavator (100b) comprising: an undercarriage (118b) comprising left (102b) and right (104b) ground engaging structures; a superstructure (106b) rotatably mounted to the undercarriage; a working arm (108b) pivotally connected to the superstructure and comprising a plurality of actuators (62b, 64b, 66b) to enable manipulation of the working arm by an operator; an operator cab (107b) mounted on the superstructure comprising a seat and operator controls for controlling the undercarriage, the working arm actuators and the rotation of the superstructure relative to the undercarriage; an engine (109b) mounted aft of the operator cab on a plurality of engine mounts (14); and, a counterweight (111b) mounted aft of the engine, the counterweight comprising left and right mounts (24), wherein the superstructure comprises a transverse structural member (18) which extends laterally across the excavator, the transverse structural member comprising counterweight seat (16) on which the counterweight mounts are located and at least one of the engine mounting point proximate to one of the counterweight seat; and, wherein the transverse structural member comprises a shim access aperture (34) located between the engine mounting point and the counterweight seat to allow shimming of the counterweight without removal of the counterweight from the superstructure.

Description

FIELD

[0001] This present disclosure relates to a counterweight adjustment mechanism for a slewing excavator.BACKGROUND

[0002] With reference to Figure 1A, a working vehicle is indicated at 100. The working vehicle 100 has an undercarriage 102 having a ground engaging structured comprising left and right tracks 104. In other embodiments, the undercarriage 102 may include one or more wheels or other means of propulsion instead of the tracks 104. The working vehicle 100 also has a superstructure 106 which is rotatable relative to the undercarriage 102. A slew motor 56 is provided to slew the superstructure 106 relative to the undercarriage 102. In other words, the slew motor 56 is configured to rotate the superstructure 106 relative to the undercarriage 102 about a vertical axis. In the illustrated embodiment, the slew motor 56 is a hydraulic slew motor.

[0003] The working vehicle 100 also has a working arm 108. The working arm 108 is pivotally connected to the superstructure 106 but is fixed laterally and longitudinally relative to the superstructure 106. In particular, the working arm 108 extends from a front end 120 of the superstructure, so that as the superstructure 106 is slewed by the hydraulic slew motor 56, the working arm 108 slews with it.

[0004] In this embodiment, the working arm 108 includes: a boom 110 which is pivotally connected to the superstructure 106; a dipper arm 112 which is pivotally connected to the boom 110; and a bucket 114 which is pivotally connected to the dipper arm 112.

[0005] The working arm is actuated by one or more working arm actuators 62, 64, 66. In particular, there is: a boom actuator 62 for pivoting the boom 110 relative to the superstructure 106; a dipper arm actuator for pivoting the dipper arm 112 relative to the boom 110; and a bucket actuator for pivoting the bucket 114 relative to the dipper arm 112. In this embodiment, the working arm actuators 62, 64, 66 are hydraulic cylinders.

[0006] In the illustrated orientation, the superstructure 106 of the excavator is slewed relative to the undercarriage so that the working arm 108 extends perpendicular to a front end 116 of the undercarriage 102. In other words, the front end 120 of the superstructure 106 and the front end 116 of the undercarriage 102 are approximately parallel. In this orientation, a rear end 122 of the superstructure 106 overhangs a rear end 118 of the undercarriage 102. Such a configuration will be referred to as a "conventional excavator".

[0007] Figure 1B shows an alternative excavator 100 known as a "reduced tail swing excavator". The reduced tail swing excavator 100 of Figure 1B is similar to the conventional excavator 100 of Figure 1A, but in this embodiment the rear end 122 of the superstructure 106 does not overhang the rear end 118 of the undercarriage 102. This may be known as a "zero tail swing excavator". In other embodiments, the rear end 122 of the superstructure 106 of the reduced tail swing excavator 100 may still overhang the rear end 118 of the undercarriage 102, but to a lesser extent than in a conventional excavator.

[0008] Providing a reduced tail swing on an excavator presents challenges for the layout of the machines and the packaging of the engine, cooling pack and hydraulics which, in terms of performance and size, are similar to corresponding conventional tail swing machines.

[0009] The present disclosure seeks to provide an improved reduced tail swing excavator.SUMMARY

[0010] The present disclosure provides a reduced tail swing excavator according to the appended claims.

[0011] The present disclosure provides a reduced tail swing excavator comprising: an undercarriage comprising left and right ground engaging structures; a superstructure rotatably mounted to the undercarriage; a working arm pivotally connected to the superstructure and comprising a plurality of actuators to enable manipulation of the working arm by an operator; an operator cab mounted on the superstructure comprising a seat and operator controls for controlling the undercarriage, the working arm actuators and the rotation of the superstructure relative to the undercarriage; an engine mounted aft of the operator cab on a plurality of engine mounts; and, a counterweight mounted aft of the engine, the counterweight comprising left and right mounts.

[0012] The superstructure may comprise a transverse structural member which extends laterally across the excavator, the transverse structural member comprising counterweight seat on which the counterweight mounts are located and at least one of the engine mounting point proximate to one of the counterweight seat.

[0013] The transverse structural member may comprise a shim access aperture located between the engine mounting point and the counterweight seat to allow shimming of the counterweight without removal of the counterweight from the superstructure.

[0014] Providing a shim access aperture between the engine mounting point and the counterweight seat allows the counterweight position to be adjusted to account for manufacturing tolerances. Adjusting the counterweight position in this way provides an efficient and convenient way to control the build gaps between the counterweight and the body panels.

[0015] The counterweight may comprise an uppermost surface and a lowermost surface, and wherein the transverse structural member is located in a mid-portion between the uppermost and lowermost surfaces.

[0016] At least one engine mounting point may be provided on an upstand extending upwardly from the transverse structural member.

[0017] The engine mounting point may be located at least partly over the shim access aperture.

[0018] An underside of the engine mounting point may be viewable from the shim access aperture.

[0019] The access apertures may comprise a rectangular aperture having a longitudinal axis extending parallel to the longitudinal axis of the excavator. The longitudinal axis may be referred to as the fore-aft axis and the axial direction the working arm lies along.

[0020] The access apertures may be exposed on an underside of the superstructure.

[0021] The access apertures may comprise two access apertures, the two access apertures being spaced longitudinally along the transverse structural member.

[0022] The transverse structural member may comprise a horizontal plate which extends laterally across the width of the superstructure on which the counterweight seats and engine mounting points are provided. A transverse vertical plate may extend downwardly from a forward edge of the horizontal plate.

[0023] The transverse structural member may comprise left and right hand longitudinal structural beams extending forward thereof under the engine. The longitudinal structural beams may comprise, in combination, a working arm pivot mount adjacent the operator cab.

[0024] The transverse structural beam may comprise at least a pair of rear engine mounting points. The left hand longitudinal structural beam may comprise at least one forward engine mounting point. The right hand longitudinal structural beam may comprise at least one forward engine mounting point.

[0025] The engine mounts may be provided to the right hand side of the counterweight mounts.

[0026] The counterweight seats may be flanked on an outer edge thereof by one or more structural components.

[0027] The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the aspects, embodiments or examples described herein may be applied mutatis mutandis to any other aspect, embodiment or example. Furthermore, except where mutually exclusive, any feature described herein may be applied to any aspect and / or combined with any other feature described herein.BRIEF DESCRIPTION OF DRAWINGS

[0028] Embodiments will now be described by way of example only with reference to the accompanying figures, in which: Figure 1A shows a schematic side view of an excavator; Figure 1B shows a schematic side view of a reduced tail swing excavator, according to an embodiment; Figure 2 shows an internal view of the superstructure frame, engine mounts and the counterweight mounts; Figure 3 shows a top down view of the engine in situ; Figure 4 shows a the counterweight from behind the superstructure; Figure 5 shows the underside of the superstructure with access apertures of the present disclosure; Figure 6 shows a section view of the counterweight fixings; and, Figure 7 shows a plan view of a shim. DETAILED DESCRIPTION

[0029] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of various embodiments and the inventive concept.

[0030] However, those skilled in the art will understand that: the present invention may be practiced without these specific details or with known equivalents of these specific details; that the present invention is not limited to the described embodiments; and, that the present invention may be practiced in a variety of alternative embodiments. It will also be appreciated that well known methods, procedures, components, and systems may have not been described in detail.

[0031] With reference to Figures 2 to 6, there is shown an internal view of the superstructure 106b which principally comprising a frame of interconnected structural members to provide support and rigidity required for the various components carried by the superstructure 106b. Typically, a superstructure frame will comprise cab mounts 12, engine mounting points 14, counterweight seats 16, a hydraulic tank (not shown), a fuel (e.g. diesel) tank (not shown) and various ancillary components required for operation.

[0032] In the illustrated embodiment, the superstructure frame comprises a rear transverse structural member 18 which extends laterally across the machine from left to right (as defined in Figure 1b) and provides support for the engine mounting points 14 and the counterweight seats 16.

[0033] A pair of beams 20 extend longitudinally forward from the rear transverse structural member 18 and define in combination a working arm pivot mount 22 adjacent the operator cab 107b. Rear engine mounting points 14R are provided on the rear transverse structural member 18, with forward engine mounts 14F being provided on the longitudinal structural beams. A deck plate may be incorporated to connect the rear transverse structural member and two longitudinal structural beams 20. The term "longitudinal" for the structural beams is used to mean that the beams are longitudinally aligned with the fore-aft axis of the superstructure and working arm 108b.

[0034] The counterweight 111b is attached to the very rear of the superstructure 106b by a pair of counterweight mounts 24. The counterweight mounts 24 in the illustrated embodiment each comprise a projecting arm which extends forward of a main body of a counterweight and overhang the rear transverse structural member 18. Underside of each projection comprises a planar abutment which is received on the counterweight seat of the transverse structural member and attached with mechanical fixings as described below. It will be appreciated that the shape and form of counterweight projections may differ from the illustrated embodiment.

[0035] As can be seen from the top down view provided in Figure 3, the engine 109b accommodates the majority of the space behind the cab 107b with the cooling pack (not shown) being located to the left of the engine 109b in the area denoted by 26 and a hydraulic pump (not shown) located to the right in the area denoted by 28. The engine 109b is mounted to the structural frame via the mounting points 14, each of which receives an anti-vibration mounting piece 44 which is in turn connected to a mounting arm 45 which extends from the engine. Although obscured from view in Figure 3, there is a similar mounting arrangement for the rear left engine mounting point 14R.

[0036] The counterweight 111b is typically constructed from cast iron or concrete and provided aft of the engine 109b and is necessarily in close proximity to provide the reduced tail swing of the excavator. In the illustrated embodiment, as best seen in Figure 4, the counterweight 111b comprises a central section 30 which extends from an uppermost surface 32 down to a lowermost surface 33 thereby defined the external rear surface of the superstructure 106b. The curvature of the rear external face of the counterweight 111b is coaxial with the slewing axis of the excavator 100b.

[0037] The central section 30 of the counterweight is flanked by laterally extending arms 35 which wrap around the lower rear corners of the superstructure 106b on the left and right side respectively thereby defining the width of the counterweight 111b and the machine generally. The spaces above the laterally extending arms 35 are closed off by hinged access panels (not shown) shaped to maintain the curved profile of the external surface of the counterweight 111b. The end faces of the arms 35 and the access panels each abut body work panels which line the sides of the superstructure and the uppermost surface of the counterweight may dressed with a body panel which extends up on to the engine hood (not shown).

[0038] The rear transverse structural member 18 and counterweight mounts 24 which project forward from an internal surface of the counterweight 111b of the central section 30 are provided in a mid-height portion of the counterweight 111b between the uppermost and lowermost surface. Referring to Figures 5 and 6, the counterweight 111b is fixed to the transverse structural member 18 by a plurality of mechanical fixings. In the illustrated embodiment, the mechanical fixings comprise bolts 36 which are received from the underside of the counterweight 111b into a capping plate 38 which has blind captive nuts 40 welded on an upper surface thereof. The bolts 36 extend through clearance apertures in the counterweight mounts 24 thereby rigidly clamping the counterweight 111b to the counterweight seat and structural frame upon tightening. It will be noted that the capping plate 38 is itself bolted to an upper surface of the counterweight mounts 24 such that they can be held in position for receiving the bolts 36 once the engine 109b and counterweight 111b are installed.

[0039] In order to facilitate the assembly of the excavator 100b, it is desirable to locate the engine 109b on the engine mounting points 14 prior to installing the counterweight 111b. In doing so, it is possible to install the engine and install and connect any required components such as the cooling pack, wiring harness, hydraulic lines etc, amongst others. However, on a reduced tail swing machine this can make the attachment of the counterweight troublesome.

[0040] Attaching the capping plate 38 to the upper surface of the counterweight mounts goes some way to overcoming this difficulty in that it allows the bolts 36 to be inserted from an underside of the superstructure 106b and tightened as required.

[0041] However, manufacturing tolerances can lead to a misalignment of the counterweight 111b and the access panels (not shown) with the surrounding body panels and engine hood. Ordinarily, these sort of misalignments may be corrected with the placement of shims under the counterweight 111b. However, this is not possible due to the proximity of the engine 109b to the counterweight 111b and the placement of the engine mounting points 14 relative to the counterweight seats 16. As such, it can make it difficult to adjust the height of the counterweight 111b using conventional shims without fully removing the counterweight 111b to insert the shims 31. As will be appreciated, a counterweight 111b is a heavy component by design and can be time consuming and cumbersome to remove.

[0042] Figure 7 shows a shim 31 contemplated for use in the present disclosure which in and of itself is conventional and takes the form of a thin plate of metal with a known thickness of reasonably high tolerance which can be used individually or in combination with others of the same or different thicknesses to provide the necessary height adjustment for the counterweight 111b. The shim includes an open ended slot to allow it to be received around one of the fixing bolts 36.

[0043] In order to retain the convenience of shims 31 whilst avoiding the need to remove the counterweight 111b to allow for adjustment, shim access apertures 34 are provided which allow the counterweight 111b to be lifted by a small amount, typically between 25-50 millimetres, before inserting a shim 31 between the underside of the counterweight mount 24 and the counterweight seat 16. Once inserted, the counterweight 111b can be bolted down. In the illustrated embodiment, the shim access apertures 34 are provided in the rear transverse structural member 18. Thus, there is provided a convenient way of adjusting the height of a counterweight with minimal interference to the assembly process.

[0044] Referring to figure 5, there is shown to access apertures 34 longitudinally separated along the length of the rear transverse structural member 18. Each access aperture 34 is generally rectangular so as to better receive a shim 31 and the width of an operator's hand and enable a shim 31 to be slid into place with the fingers underneath the counterweight mount 24. It can also be seen that the deck plate 19, is shaped on the rear edge thereof to allow access to the calculate attachment bolts and access apertures.

[0045] The rear edge of the deck plate 19 also includes a plurality of lobes 19' for receiving upright members which extend forward into the longitudinal structural beams 20 described above. It can also be seen that the inner edge at the rear underside portion of the counterweight 111b is shaped to accommodate the rear most bolts 36 and access apertures 34.

[0046] The access apertures 34 are both placed centrally with respect to their respective counterweight mounts 24 allowing the design of the counterweight 111b to be simpler. That is, providing the access apertures 34 as viewed from underneath in Figure 5 in a central portion means the position of the apertures 34 is radially close it to the slew axis than they would be if they were placed on the outer side of the counterweight mounts 24. Further, there are additional attachment points / bracketry 42 on the lateral outer portions of the counterweight seats 16 for anchoring a structural framework for supporting the hood and some ancillary components of the engine 109b.

[0047] In order to facilitate the placement and positioning of the access apertures 34, the engine mounting points 14 maybe provided on upstands to provide sufficient clearance for an assembly worker's hands or an appropriate tool to be received through the aperture 34 with the shim 31, and for the shim 31 to be slid into place underneath the counterweight mount 24. Thus, as can be seen on the right hand side of Figure 2, the mounting point 14 is provided on an upstand which extends upwards and overarches the access aperture 34.

[0048] Providing the access aperture 34 underneath the engine mounting point 14 in this way, also provides an inspection window from which the underside of the engine mount 44 can be viewed without removing the counterweight. It will be noted that the other engine mounting points may all be located in positions which can be seen from elsewhere in the machine however the rearmost left hand and the mount is obscured by the counterweight and by the counterweight mount.

[0049] The engine mounting points 14 can take any suitable form for supporting the engine 109b.

[0050] The longitudinal structural beams may comprise an upper plate and a lower plate (which in this illustrated embodiment is the four mentioned deck plate). A central web extends between the upper and lower plates to provide an I-beam structure. The forward engine mounting may be cantilevered off the central web to provide pads in the required location.

[0051] The present disclosure provides a reduced tail swing excavator in which the counterweight may be shimmed without too much disruption to the assembly line. This aids the aesthetic appearance and build quality of the machine as it allows the counterweight to be adjusted to match the body panels. It also allows the counterweight to be potentially shimmed whilst the body panels are in situ.

Claims

1. A reduced tail swing excavator (100b) comprising: an undercarriage (118b) comprising left (102b) and right (104b) ground engaging structures; a superstructure (106b) rotatably mounted to the undercarriage; a working arm (108b) pivotally connected to the superstructure and comprising a plurality of actuators (62b, 64b, 66b) to enable manipulation of the working arm by an operator; an operator cab (107b) mounted on the superstructure comprising a seat and operator controls for controlling the undercarriage, the working arm actuators and the rotation of the superstructure relative to the undercarriage; an engine (109b) mounted aft of the operator cab on a plurality of engine mounts (14); and, a counterweight (111b) mounted aft of the engine, the counterweight comprising left and right mounts (24), wherein the superstructure comprises a transverse structural member (18) which extends laterally across the excavator, the transverse structural member comprising counterweight seat (16) on which the counterweight mounts are located and at least one of the engine mounting point proximate to one of the counterweight seat; and, wherein the transverse structural member comprises a shim access aperture (34) located between the engine mounting point and the counterweight seat to allow shimming of the counterweight without removal of the counterweight from the superstructure.

2. The excavator of claim 1, wherein the counterweight comprises an uppermost surface and a lowermost surface, and wherein the transverse structural member is located in a mid-portion between the uppermost and lowermost surfaces.

3. The excavator of either of claims 1 or 2, wherein at least one engine mounting point is provided on an upstand extending upwardly from the transverse structural member.

4. The excavator of claim 3, wherein the engine mounting point is located at least partly over the shim access aperture.

5. The excavator of claim 4, wherein an underside of the engine mounting point is viewable from the shim access aperture.

6. The excavator of any preceding claim, wherein the access apertures comprise a rectangular aperture having a longitudinal axis extending parallel to the longitudinal axis of the excavator.

7. The excavator of any preceding claim, wherein the access apertures are exposed on an underside of the superstructure.

8. The excavator of any preceding claim, comprising two access apertures, the two access apertures being spaced longitudinally along the transverse structural member.

9. An excavator of any preceding claim, wherein the transverse structural member comprises a horizontal plate which extends laterally across the width of the superstructure on which the counterweight seats and engine mounting points are provided, and a transverse vertical plate extending downwardly from a forward edge of the horizontal plate.

10. An excavator of any preceding claim, wherein the transverse structural member comprises left and right hand longitudinal structural beams extending forward thereof and under the engine, the longitudinal structural beams comprising in combination a working arm pivot mount adjacent the operator cab.

11. An excavator of claim 9, wherein the transverse structural beam comprises at least a pair of rear engine mounting points, and the left hand longitudinal structural beam comprises at least one forward engine mounting point, and the right hand longitudinal structural beam comprises at least one forward engine mounting point.

12. An excavator of any preceding claim wherein the engine mounts are provided to the right hand side of the counterweight mounts.

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