AU2013203390A1

AU2013203390A1 - A rotator for connecting a timber-working implement to a forestry work machine

Info

Publication number: AU2013203390A1
Application number: AU2013203390A
Authority: AU
Inventors: Keith POOLEY
Original assignee: Waratah NZ Ltd
Current assignee: Waratah NZ Ltd
Priority date: 2013-02-28
Filing date: 2013-02-28
Publication date: 2014-09-18
Also published as: WO2014133399A1

Abstract

The invention relates to a forestry work machine, a timber-working implement, and a rotator for connecting the timber working implement to a boom of the forestry work machine. The rotator includes a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a housing. The rotator further includes a pivotal connection and a rotary electrical interface between the first part and the second part. A junction enclosure is located within the housing, configured to receive an electrical cable extending from the boom. An electrical connector is positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, and wherein the junction enclosure is configured to contain at least one loop of the cable.

Description

A ROTATOR FOR CONNECTING A TIMBER-WORKING IMPLEMENT TO A FORESTRY WORK MACHINE TECHNICAL FIELD 5 The present invention relates to a rotator for connecting a timber-working implement to a forestry work machine. BACKGROUND ART It is well-known to mount a timber-working head, for example in the form of a harvesting head, 10 to a forestry work machine to perform a number of functions in connection with timber. Such heads may be used to grapple and fell a standing tree and process the felled tree by delimbing, possibly debarking (depending on the configuration of the head), and cutting the stem of the tree into logs of predetermined length. In order to assist in correctly positioning the harvester head during its various tasks, a rotator is 15 commonly positioned between the harvester head and the crane arm of the forestry working machine. The rotator is typically hydraulically driven, and provides the machine operator with control over pivotal rotation of the harvester head about the connection to the crane arm. Hydraulic circuits associated with various functions of the harvester head are supplied with pressurized hydraulic medium via hoses connected to a hydraulic pump and reservoir on the 20 carrier vehicle, and running the length of the crane arm. These hoses have sufficient length and flexibility to allow for rotation of the harvester head about the rotator through substantially 3600. It is also necessary to supply electrical power to the harvester head from power sources on the carrier. This requires electrical cable, typically formed of bundles of conductive strands, to be 25 passed the length of the crane arm and connected to the harvester head. This cable is more susceptible to damage due to twisting and flexing than the hydraulic hoses. It is not ideal to cater for rotation of the head by providing slack in the cable as with the hydraulic hoses, as the length required to achieve this would likely make the cable highly susceptible to snagging on objects in the vicinity of the head. 30 In order to address this issue, it is known to transfer the electrical power across the rotator using slip rings. As a result, the electrical cable is not exposed to the twisting forces which would otherwise be applied to the cable due to rotation of the harvester head relative to the crane arm, and the risk of damage is greatly reduced.

However, issues remain with terminating the cable at the rotator. Currently, at least a portion of the cable is exposed within the rotator housing. Portions of trees being processed, or other forms of debris, may catch on the cable and cause a break to occur at some point along its length. As the cable may be in the order of five meters in length, this may be a significant 5 expense - both in terms of material cost, and also service time. Further, pulling on the cable can damage the slip rings themselves, the replacement of which is also an expensive exercise. In order to reduce these effects, it is known to provide a connector at some point along the length of the cable, with the intention that the connector will fail in place of the cable itself. Such connectors may be housed within junction boxes at the rotator, with the cable installed 10 such that a loop of cable leads into each point of entry into the junction box. The loops are intended to compensate for the cable catching and being pulled to a limited degree. However, the loops of cable remain exposed and susceptible to damage. Further, there are different configurations of wiring of the electrical cable along the crane arm. For example, the cable may be carried along the exterior of the crane arm until extending from 15 the crane arm to the side of the rotator. However, it is also known for the cable to pass through the interior of at least the end portion of the crane arm, from its tip and downwardly into the rotator. It may be useful for any arrangement for protecting the cable to cater to both configurations. It is an object of the present invention to address the foregoing problems or at least to provide 20 the public with a useful choice. All references, including any patents or patent applications, cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the reference states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood 25 that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents forms parts of the common general knowledge in the art, in New Zealand or in any other country. Throughout this specification, the words "comprise" or "include", or variations thereof such as "comprises" or "comprising", or "includes" or "including" will be understood to imply the inclusion 30 of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. 35 DISCLOSURE OF THE INVENTION According to one aspect of the present invention there is provided a rotator for connecting a timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the 5 boom and the implement respectively, wherein the first part includes a housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable extending from the boom; and 10 an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable. According to another aspect of the present invention there is provided a timber-working 15 implement, including: a rotator for connecting the timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a 20 housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable extending from the boom; and 25 an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable. 30 According to another aspect of the present invention there is provided a forestry work machine, including: a carrier; an electrical power source positioned on the carrier; a boom supported by the carrier; and a timber-working implement, including: 5 a rotator for connecting the timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a housing; 10 a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable electrically connected to the electrical power source, and extending from the boom; and 15 an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable. 20 Preferably the rotator includes a rotary drive mechanism configured to control rotation of the first part and second part relative to each other about the pivotal connection. It should be appreciated that the rotary drive mechanism may be any suitable means known to a person skilled in the art, whether hydraulically or electrically powered. For example, the rotary drive mechanism may be a hydraulic motor. 25 Reference to a rotary electrical interface should be understood to mean a device in which an electric current may be transmitted between at least two rotating parts. In a preferred embodiment the rotary electrical interface includes a slip ring assembly, but it should be appreciated that other devices are envisaged - for example an inductive power transfer device. It is envisaged that the rotary electrical interface may be incorporated into a rotary union unit 30 used to convey fluid across the pivotal connection, as known in the art. In a preferred embodiment the housing includes a structure for facilitating connection to the boom. In an exemplary embodiment, the housing may include hinge points to which one end of a link, such as a dog-bone joint, may be connected, and connected to the boom at the other end. By providing sufficient space within the enclosure to contain at least one loop of cable, the risk of that cable becoming snagged on objects which make their way into the housing is reduced. 5 It should be appreciated that the internal dimensions of the junction enclosure may vary between timber-working implements - for example due to variation in cable properties such as curvature and/or bend radius. In the event that the cable does become caught and is pulled, the slack in the cable within the junction enclosure may allow for displacement of the cable without being exposed to tensile 10 stress which may cause a break in one or more of the conductors in the electrical cable. In an exemplary embodiment, the rotator includes a secondary cable extending from the electrical connector to the rotary electrical interface. It is envisaged that the length of cable within the junction enclosure is equal to, or greater than, the length of the secondary cable within the junction enclosure. In doing so, an additional degree of slack in the cable may be 15 provided following disconnection of the electrical connector. This additional length may make the difference between the cable being compromised and requiring replacement, or simply disconnected. Preferably the rotator may include a passage leading to the rotary electrical interface, and the junction enclosure is positioned such that an outlet aperture in a bottom wall of the enclosure 20 substantially aligns with the passage. In doing so, the distance that the cable needs to travel may be minimised - particularly through an exposed and unprotected space. According to another aspect of the present invention there is provided a rotator for connecting a timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the 25 boom and the implement respectively, wherein the first part includes a housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable extending from the boom; and 30 an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the rotator includes a passage leading to the rotary electrical interface, and the junction enclosure is positioned such that an outlet aperture in a bottom wall of the enclosure substantially aligns with the passage. In one embodiment, the outlet aperture may include a conduit between the junction enclosure 5 and the passage to the rotary electrical interface. For example, a gland or sealed fitting may span any gap between the outlet and the passage. It is envisaged that in doing so, the potential for the cable - particularly the connection to the rotary electrical interface - becoming caught by tree parts or other debris may be minimised. In another embodiment, the outlet aperture may be seated against the passage to the rotary 10 electrical interface. Similarly to above, this may reduce the potential for the cable to become damaged. Preferably the junction enclosure includes a first inlet aperture positioned on a side wall of the enclosure and a second inlet aperture positioned on a top wall of the enclosure. In doing so, the enclosure may be readily configured to be used with different boom configurations in terms 15 of the electrical cable - both through the side of the housing, and also through the top. In a preferred embodiment the junction enclosure includes a sealed fitting at the inlet through which the electrical cable is to enter. For example, it is envisaged that a flare fitting may be provided at the inlet. It is envisaged that the electrical cable may be contained within a hose, and a flare nut used to secure the hose to the flare fitting. In doing so the hose creates a 20 sealed passage, protecting the cable from environmental effects. The aperture not used for enabling entry of the cable may be sealed using any suitable means known to a person skilled in the art. The enclosure may include a removable panel to assist in accessing the electrical connector, and creating the loop of cable within the enclosure. Preferably the removable panel includes a 25 water resistant seal. Previous junction enclosures have been susceptible to shorting of the connector due to moisture within the enclosure, particularly condensation. Preferably the enclosure includes an unsealed aperture on a downward facing side of the enclosure. In doing so, the aperture may act as a snorkel - allowing airflow into the enclosure and drainage of any moisture. 30 It is envisaged that the outlet aperture in the bottom wall of the enclosure may include a raised lip on the interior of the enclosure. This raised lip may assist in isolating the cable from moisture pooling in the base of the enclosure prior to draining from the snorkel. Preferably the electrical connector may be a sealed connector to assist in preventing shorting between the connections. Further, the force required to separate the parts of the connector 35 may be less than the yield stress of the wire - providing an additional degree of protection for the rotary electrical interface and its connection to the electrical cable in particular. By preserving the integrity of these components, a significant cost both in terms of materials and also repair technician time may be saved. The rotator may include a support bracket located within the housing, to which the junction 5 enclosure is mounted. It is anticipated that the enclosure may be subjected to the application of force from various sources in the working environment of the timber working machine, and were the enclosure to move the electrical cable may be damaged, or lead to the fitting being loosened. It is envisaged that the bracket may assist in preventing movement of the enclosure within the housing - particularly relative to the passage leading to the rotary electrical interface. 10 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a forestry work machine according to one embodiment of the present invention; FIG. 2 shows a side view of a rotator according to an embodiment of the present invention; 15 FIG. 3A shows a top perspective view of a junction enclosure according to a further embodiment of the present invention; FIG. 3B shows a top perspective view of a junction enclosure according to a further embodiment of the present invention, and FIG. 4 shows a top view of a rotator according to an embodiment of the present invention. 20 DETAILED DESCRIPTION FIG. 1 illustrates a forestry work machine (generally indicated by arrow 1) including a carrier 2 supporting an articulated boom 3. A timber working implement in the form of a harvester head 4 is connected to an end of the boom 3, using a dog-bone joint 5 connected to a rotator 6, 25 which is in turn connected to the frame of the head 4 by hanger 7. In operation, the head 4 may swivel relative to the end of the boom 3 about the rotator 6, and pivotally move about its connection to the hanger 7 between a generally upright, harvesting position for felling a tree and a generally prone, processing position for processing the felled tree (e.g., delimbing, debarking, cutting to length). 30 An electrical power source (not illustrated) is positioned on the carrier 2. It is envisaged that the power source will be batteries, but may be other energy storage devices such as super or ultracapacitors, or a generator such as an alternator of the machine 1. An electrical cable connected to the power source extends the length of the boom 3. At the end of the boom, the electrical cable may extend from the tip of the boom 3 down into the rotator 6 - as illustrated by dashed line 8. In another embodiment, the electrical cable may extend into the side of the rotator 6 as illustrated by dashed line 9. FIG. 2 illustrates an exemplary rotator (generally indicated by arrow 200) which may be used as 5 rotator 6 in the timber working machine 1 illustrated in FIG. 1. The rotator 200 includes a housing 201 to which a boom, such as boom 3 of FIG. 1 may be connected. In particular, the housing 201 includes hinge points 203a and 203b to which the dog-bone joint 5 may be connected. The rotator 200 is pivotally connected to a hanger 204, which may be used as hanger 7 in the 10 timber working machine 1 illustrated in FIG. 1. A rotary union unit 205, including a slip ring assembly (not illustrated) providing a rotary electrical interface across the connection between the housing 201 and hanger 204, is connected to the housing 201 and hanger 204. The rotator 200 further includes a junction enclosure 207, which will herein be described with reference to FIG. 3A and FIG. 3B. The junction enclosure 207 includes a side wall 208, top 15 wall 209, and bottom wall 210 formed from a single steel plate. An opposing side wall 211, angled to fit within the housing 200, and rear wall 212 are formed from another steel plate. The junction enclosure 207 is constructed by welding the plates together. It should be appreciated that this is not intended to be limiting, and that in other embodiments it may be, for example, a steel casting. 20 A removable front panel 213 may be fastened to the junction enclosure 207 via bolts inserted into support plates 214 and 214'. Resilient seals (not illustrated) may be used to assist in creating a water resistant seal between the front panel 213 and the enclosure 207. The junction enclosure 207 includes an outlet aperture 215 in the bottom wall 210, a first inlet aperture 216 in the side wall 208 and a second inlet aperture 217 in the top wall 209. The 25 bottom wall 210 also includes a breathing aperture 218 which allows airflow into the enclosure and drainage of any moisture. Positioning the breathing aperture 216 on the bottom wall 216 may reduce the likelihood of ingress of water or dust into the enclosure 207 in comparison with the other more exposed walls. Referring to FIG. 4A, electrical cable 8 enters through the top of the housing 202, and through 30 an inlet fitting 219 fitted to the second inlet aperture 217 of FIG. 3A. It is envisaged that the fittings used at the inlets of the junction enclosure may be configured to be coupled to hoses for example JIC fittings commonly used in hydraulic plumbing. The electrical cable may pass through the hose, which would provide an additional degree of protection from the harsh timber working environment the machine 1 is likely to be used in. As such, the fittings, for example 35 inlet fitting 219, may seal both the junction enclosure and also the protective hosing.

On entry to the junction enclosure 207, a loop 220 of the cable 8 is created, and the end of the cable 8 terminated at a first part of a releasable electrical connector 221. The matching part of the connector 221 is electrically connected to a secondary cable 222, which passes through outlet aperture 215, through a fitting 223 in the rotary union unit 205 defining an entry to a 5 passage leading to the slip rings (not illustrated), and connects to the slip rings. FIG. 4B illustrates the passage 224 between the fitting 223 and the slip rings 225. The junction enclosure 207 is positioned within the housing 202 such that the outlet aperture 215 substantially aligns with the fitting 223. Returning to FIG. 4A, it may be seen that by doing so, the distance that the secondary cable 10 222 needs to travel through the housing 202 is reduced. This alignment also assists in protecting the secondary cable 222, as a conduit in the form of outlet fitting 226 may extend directly between the outlet aperture 215 and fitting 223. The vertical alignment means that the conduit does not need to pass through a convoluted path which may otherwise increase the complexity of manufacture and installation. 15 The housing 202 also includes a support bracket 227, to which the junction enclosure 207 is mounted. The support bracket 227 assists the outlet fitting 224 in maintaining the orientation of the junction enclosure 207. In particular, it is envisaged that the support bracket 227 may resist rotation of the enclosure 207 about the screw threads of the fitting 223 where force is applied to the side of the enclosure 207. While other components within the housing 202 may prevent 20 complete rotation of the enclosure 207, even repeated turning in different directions within a limited angle may lead to the fitting 223 becoming lose and ultimately released from either the junction enclosure 207 or the rotary union unit 205 - leaving the enclosure 207 "floating" within the housing 202 and creating a target for snaring and pulling of the secondary cable 222 in particular. 25 The support bracket 227 prevents this from occurring, and thus means that the junction enclosure 207 may be releasably attached via fitting 223 rather than requiring fasteners to the enclosure 207 itself, or permanent connection, for example though welding. This assists in improving the ease of installation, and also lends to ease of removal for maintenance or inspection of other components within the housing 202. 30 In the event that cable 8 becomes caught by debris in the span between the inlet 219 and the exit point from boom 3, the slack created by loop 220 allows for a length of the cable 8 to be pulled from the junction enclosure 207 rather than the tension creating a break at some point along the cable 8, while maintaining an electrical connection with the slip rings 225. Should this distance be exceeded, the force overcomes the connection between the two parts 35 of the connector 221 before sufficient tension to damage the secondary cable 222 may be applied. While the main cable 8 may be damaged and require repair or replacement, the integrity of the secondary cable 222 and slip rings 225 may be preserved. FIG. 5 illustrates the rotator 200 in an embodiment in which the cable 9 is to be connected to the slip rings 225 of FIG. 4B. The configuration of the rotator 200 is substantially the same as 5 that illustrated by FIG. 2. However, in this case the cable 9 passes through an inlet fitting 228 fitted to the first inlet aperture 216, with second inlet aperture 217 sealed by a plug 229. This illustrates the ease with which the rotator 200 may be adapted to the two different commonly used wiring configurations of the boom 3. Aspects of the present invention have been described by way of example only and it should be 10 appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

Claims

1. A rotator for connecting a timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable extending from the boom; and an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable.

2. The rotator as claimed in claim 1, wherein the rotator includes a passage leading to the rotary electrical interface, and the junction enclosure is positioned such that an outlet aperture in a bottom wall of the enclosure substantially aligns with the passage.

3. The rotator as claimed in claim 2, wherein the outlet aperture includes a conduit between the junction enclosure and the passage to the rotary electrical interface.

4. The rotator as claimed in claim 2, wherein the outlet aperture is seated against the passage to the rotary electrical interface.

5. The rotator as claimed in any one of claims 1 to 4, wherein the junction enclosure includes a first inlet aperture second inlet aperture positioned on a side wall of the enclosure and a second inlet aperture positioned on a top wall of the enclosure.

6. The rotator as claimed in any one of claims 1 to 5, wherein the rotator includes a bracket located within the housing, to which the junction enclosure is mounted.

7. A timber-working implement, including: a rotator for connecting the timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable extending from the boom; and an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable.

8. A forestry work machine, including: a carrier; an electrical power source positioned on the carrier a boom supported by the carrier; and a timber-working implement, including: a rotator for connecting the timber working implement to a boom of a forestry work machine, including: a body having a first part and a second part configured to be connected to an end of the boom and the implement respectively, wherein the first part includes a housing; a pivotal connection between the first part and the second part; a rotary electrical interface between the first part and the second part; a junction enclosure located within the housing, configured to receive an electrical cable electrically connected to the electrical power source, and extending from the boom; and an electrical connector positioned within the junction enclosure, wherein the connector is electrically connected to the rotary electrical interface and is configured to be releasably connected to the electrical cable, wherein the junction enclosure is configured to contain at least one loop of the cable.

9. A rotator for use with a timber-working device, substantially as herein described with reference to and illustrated by the accompanying figures and associated description.

10. A timber-working implement, substantially as herein described with reference to and illustrated by the accompanying figures and associated description.

11. A forestry work machine, substantially as herein described with reference to and illustrated by the accompanying figures and associated description.