STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the specification filed in relation to New Zealand Patent Application Number 608420, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a timber-working head. More particularly the present invention relates to a timber-working head comprising a drive wheel arm.

BACKGROUND

It is well-known to mount a timber-working head, for example in the form of a harvesting head, 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.

Processing the felled tree typically involves feeding the resulting stem along its length relative to the head using a feed mechanism. One well known system uses arm mounted rotary drives having a drive wheel at the end of opposing drive arms. The arms are driven by hydraulic cylinders to pivot relative to the frame of the head in order to grapple the stem with the drive wheels. The drive wheels are then driven in the desired direction.

The rotary drives used to rotate the drive wheels are typically hydraulically driven, and require the delivery of hydraulic fluid across the pivotal connection between the frame and the drive arms. To date, this has been achieved using flexible hosing routed across the junction between the frame and the drive arms.

Components used in or with harvester heads are generally exposed to harsh operating conditions - both in terms of the shock and vibration generated during use and operation of the head, and also the high levels of dust, dirt, snow, and debris present in the surrounding environment. Externally routed hosing in the vicinity of the stem is particularly susceptible to snagging on debris such as branches.

Damage to the hosing typically requires its replacement in order to permit safe and effective operation of the harvester head. Within the forestry industry harvesters are required to maintain high levels of productivity, and any downtime of the machine while it is being repaired can heavily impact on its efficacy.

It is an object of the present invention to address the foregoing problems or at least to provide 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 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" of "include", or variations thereof such as "comprises", "includes", "comprising", or "including", will be understood to imply the inclusion 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.

SUMMARY

According to one aspect of the present invention there is provided a timber-working head, comprising: a frame; and at least one drive wheel arm pivotally coupled to the frame, comprising: a rotary drive; and a rotary union between the frame and the rotary drive. According to another aspect of the present invention there is provided a drive wheel arm for a timber-working head, comprising: a rotary drive; a pivot sleeve to which the rotary drive is mounted; a pivotal coupling configured couple the pivot sleeve to a timber-working head; and a rotary union configured to provide fluid communication across the pivotal coupling between the timber-working head and the rotary drive.

According to a further aspect of the present invention there is provided a timber-working head, comprising: a frame; and a drive wheel arm pivotally coupled to the frame, comprising: a rotary drive; a pivot sleeve to which the rotary drive is mounted, comprising: an internal bore and an outer surface; and at least one first port between the bore and the outer surface; and a shaft positioned in the bore, comprising: at least one fluid passage, comprising a second port, wherein the second port is in fluid communication with the first port between the bore and the outer surface.

According to a further aspect of the present invention there is provided a drive wheel arm configured to be pivotally coupled to a timber-working head, comprising: a rotary drive;

a pivot sleeve to which the rotary drive is mounted, comprising: an internal bore and an outer surface; and at least one first port between the bore and the outer surface; and a shaft positioned in the bore, comprising: at least one fluid passage, comprising a second port, wherein the second port is in fluid communication with the first port between the bore and the outer surface.

In exemplary embodiments the timber-working head may be a harvester head, and may be referred to as such throughout the specification. Harvester heads typically have the capacity to grapple and fell a standing tree, delimb and/or debark a felled stem, and cut the stem into logs. However, a person skilled in the art should appreciate that the present invention may be used with other timber-working heads, for example a debarking and/or delimbing head - and that reference to the timber-working head being a harvester head is not intended to be limiting. Reference to a rotary union should be understood to mean a mechanical device configured to enable transfer of fluid between a stationary point and a rotating point - preferably providing a dynamic seal between the two points. In an embodiment of the present invention the rotary union may be incorporated into or replace components of a drive wheel arm, as will be herein described.

Reference to a pivot sleeve should be understood to mean any body having an internal bore configured to receive a shaft, about which it may pivotally move.

The pivot sleeve may comprise connection points or structures to which other components of the harvester head, and the drive wheel arm in particular, may be connected. For example, the pivot sleeve may comprise ears for pivotal connection to a linear actuator, such as a hydraulic cylinder, which drives pivotal movement of the drive wheel arm about the shaft. Further, the pivot sleeve may comprise a drive frame to which the rotary drive is mounted.

Preferably the second port of the fluid passage is positioned in a side of the shaft at a point such that it substantially aligns with the first port when the shaft is inserted into the pivot sleeve. In an exemplary embodiment the pivot sleeve may comprise a rotary manifold configured to enable fluid communication between the first port and the second port during pivotal movement of the shaft relative to the pivot sleeve. The rotary manifold may comprise a manifold bore configured to receive the shaft. The diameter of the manifold bore may be greater than the outer diameter of the shaft, creating a cavity between the shaft and the manifold bore of the rotary manifold. An aperture in the rotary manifold may connect the cavity to the first port.

The rotary manifold may comprise seals axially spaced inside the manifold bore on either side of the first port and second port. In doing so, a sealed chamber between the first and second ports is created, acting as a fluid communication pathway even as the sleeve and first port rotate relative to the shaft and second port. The seals may be any suitable type known for use in radially sealing a rotary application. In particular it is envisaged that the seals may have a hard wearing bearing surface and an elastomeric component - where as the hard bearing surface wears the elastomeric component provides compression to maintain the seal.

It is envisaged that the manifold bore may comprise annular grooves configured to receive the seals and maintain their position. However, it should be appreciated that the seals may be positioned within the manifold bore, or on the shaft.

Further, or alternatively, the rotary manifold may comprise at least one recess, and more particularly an annular recess, within the manifold bore substantially in alignment with the at least one first port. This may be used to increase the cross section of the fluid path between the first and second ports, without increasing the gap the seals need to span. In exemplary embodiments the rotary manifold may be integrally formed with the pivot sleeve. However, it is envisaged that the rotary manifold may be manufactured as a separate part, with the internal bore of the sleeve including a recessed portion configured to receive the rotary manifold. A releasable fastener, for example a threaded bush, may be used to secure the rotary manifold relative to the sleeve.

In an exemplary embodiment the diameter of the recessed portion may be greater than the outer diameter of the rotary manifold. It is envisaged that the resultant air gap between the pivot sleeve and the rotary manifold may allow the rotary manifold to float to a limited degree. This may reduce pressure on the seals, improving their longevity. Further, where loads are placed on the drive wheel arm there may be some flexure of the shaft. By allowing for some movement of the rotary manifold, the seal between fluid pathways may be maintained and stress on the components reduced.

It envisaged that a key between the pivot sleeve and the rotary manifold may be used to maintain the radial orientation of the rotary manifold during such movement. The shaft may further comprise a third port at the other end of the fluid passage. The third port may be configured to be connected to a fluid supply system as known in the art. In doing so, pressurised fluid may be supplied to, or received from, the third port.

The shaft may be a pin configured to be fastened to the frame of the timber-working head. The demands of pins in such configurations are known by manufacturers of timber-working heads, and using the shaft as a pin may allow for incorporation of a rotary union without substantive changes to other elements of the timber-working head.

According to a further aspect of the present invention there is provided a pin for pivotally coupling a drive wheel arm to a frame of a timber-working head, wherein the drive arm comprises a pivot sleeve having an internal bore and an outer surface, and at least one first port between the bore and the outer surface, the pin comprising:

a shaft configured to be positioned in the bore, wherein the shaft comprises at least one fluid passage having a second port, wherein in use the second port is in fluid communication with the first port between the bore and the outer surface.

The shaft may be configured to be fixed relative to the frame of the timber-working head. In doing so, the conduit or conduits connecting the fluid supply system to the third port(s) may not need to span a moving junction between parts of the harvester head. As a result, the conduit may be more easily protected from damage. In exemplary embodiments, a protective channel or housing may be provided. In other embodiments hard piping may be used, which is substantially less susceptible to damage than flexible hosing. The shaft may comprise a plurality of fluid passages, with associated plurality of second ports spaced along the shaft to align with first ports spaced along the pivot sleeve. This plurality of fluid passages may be plumbed such that the first ports act as inlets or outlets for the rotary drive as required. The rotary drive may be any fluid driven means known in the art, for example a hydraulic motor, suitable for driving a drive wheel to control the position of a stem grasped by the drive arms relative to the head. Reference will herein be made to the rotary drive being a hydraulic motor, and the fluid being delivered to and from the motor being hydraulic fluid - although it should be appreciated that this is not intended to be limiting. It should be appreciated that the fluid communication between the hydraulic motor and the at least one first port between the bore and the outer surface may be achieved using fittings and conduit well known in the art.

By way of example, it is envisaged that flexible hosing may be used to connect the first port and the motor. Because the envisaged structure of the sleeve between the first port and the motor does not have moving parts, this area may be shielded or enclosed to protect such flexible hoses. Such hosing may be assist with increasing the ease of eventual replacement or repair of components in this area due to the ease with which it may be manipulated and its ready availability. It should be appreciated that this is not intended to be limiting, and that hard piping may be used to connect the motor to the at least one first port.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which: FIG. 1 is a side view of a forestry work machine including a timber-working head according to one embodiment of the present invention;

FIG. 1 B is an elevated view of the timber-working head;

FIG. 2A is an side cross sectional view of an exemplary pivot sleeve for a drive wheel arm according an embodiment of the present invention; FIG. 2B is an side cross sectional view of an exemplary rotary manifold sleeve for a drive wheel arm according an embodiment of the present invention;

FIG. 2C is an side cross sectional view of the rotary manifold sleeve engaged with the pivot sleeve according an embodiment of the present invention;

FIG. 2D is an side cross sectional view of an exemplary pin for a drive wheel arm according an embodiment of the present invention;

FIG. 2E is an side cross sectional view of an exemplary drive wheel arm according an

embodiment of the present invention;

FIG. 3A is an end on view of an exemplary drive wheel arm according to another embodiment of the present invention, and

FIG. 3B is a perspective view of the exemplary drive wheel arm according to another

embodiment of the present invention.

DETAILED DESCRIPTION FIG. 1A illustrates a timber-working system including a carrier 1 for use in forest harvesting.

The carrier 1 includes an operator cab 2 from which an operator (not shown) controls the carrier 1. The carrier 1 further includes a boom assembly 3, to which a timber-working device in the form of a forestry head 4 is connected.

Connection of the head 4 to the boom assembly 3 includes a rotator 5, configured to rotate the head 4 about the generally vertical axis of rotation marked by dashed line 6. A tilt bracket 7 further allows rotation of the head 4 between a prone position (as illustrated) and a standing position.

The system, particularly harvester head 4, may be controlled by the operator of the carrier 1 using hand and foot controls as known in the art. A controller (not illustrated) controls operation of the harvester head 4 in response to data or signals received from various components of the harvester head 4 and in conjunction with the operator input devices.

Referring to FIG. 1 B, the head 4 includes a frame 8 to which the tilt bracket 7 of FIG. 1 is pivotally attached. Right hand (RH) and left hand (LH) delimb arms 9a and 9b are pivotally attached to the frame 8, as are opposing RH and LH feed arms 10a and 10b. RH and LH feed wheels 11a and 11b are attached to RH and LH drive arms 10a and 10b respectively, which together with a frame-mounted feed wheel 12 may be controlled to feed one or more stems (not illustrated) along feed axis 13 of the head 4. The arm mounted feed wheels 11a, 11 b are driven by hydraulic motors 14a and 14b, and may collectively be referred to as the 'feed mechanism.' Pressurised fluid A measuring wheel 15 may be used to measure the length of stems processed by the head 4. The measuring wheel 15 may be selectively raised and lowered into contact with the stems as desired. Alternatively, rotation or runtime of the feed wheels 11a or 11 b, may be used to measure the length of the stem as it is driven relative to the head 4. A main chainsaw 16, and a topping chainsaw 17, are attached to the frame 8. The main saw 15 is typically used to fell a tree when the head 4 is in a harvesting position, and to buck stems into logs in the processing position of the head 4 (as seen in FIG. 1A).

FIG. 2A illustrates an exemplary pivot sleeve 200 for a drive wheel arm configured to be pivotally coupled to a timber-working head, such as that illustrated in FIG. 1A and FIG. 1 B.

The pivot sleeve 200 has a hollow cylindrical body 201 from which a drive frame extends (not illustrated, but substantially as described with reference to FIG. 3A and FIG. 3B).

The cylindrical body 201 has an internal bore 202 and outer surface 203. Within the bore 202 is an annular rotary manifold recess 204, configured to receive a rotary manifold sleeve which will be described with reference to FIG. 2B below. A fitting aperture 205 between the internal bore 202 and outer surface 203 is positioned within the rotary manifold recess 204.

Threaded portions 206a and 206b are located at either end of the internal bore 202, in order to receive bushes which will be described with reference to FIG. 2C below. A key aperture 207 is also located in the side of the body 201 within the rotary manifold recess 204, the purpose of which will be discussed below with reference to FIG. 2C.

FIG. 2B illustrates an exemplary rotary manifold sleeve 208 for use with the pivot sleeve 200 illustrated in FIG. 2A. The rotary manifold sleeve 208 has a manifold bore 209, the diameter of which is greater than that of the internal bore 203 of the pivot sleeve 200. A series of first ports (210a, 210b, and 210c respectively) in the manifold bore 209 are positioned to be within the bounds of the fitting aperture 205 when the rotary manifold sleeve 208 is inserted into the rotary manifold recess 204 of the pivot sleeve 200 (as illustrated by FIG. 2C). The rotary manifold sleeve 208 has a series of annular grooves 211a, 211 b, 211c, and 211d in the manifold bore 209, positioned on either side of the first ports 210a, 210b, and 210c. Annular seals 212a, 212b, 212c, and 212d are received and held in place by the grooves 211a, 211b, 211c, and 211d respectively.

A key recess 213 in the side of the rotary manifold sleeve 208 is positioned to align with the key aperture 207 in the body 201 illustrated in FIG. 2A when the rotary manifold sleeve 208 is inserted into the rotary manifold recess 204. Positioning recesses 214 in the end of the rotary manifold sleeve 208 are configured to engage with a tool (not illustrated), used to rotate the rotary manifold sleeve 208 to align the key recess 213 with the key aperture 207.

FIG. 2C illustrates the rotary manifold sleeve 208 as received by the pivot sleeve 200. Hydraulic hose fittings 215a, 215b and 215c are fitted to the first ports 210a, 210b, and 210c to provide passages between the manifold bore 209 and outer surface 203 of the pivot sleeve 200. The insert of FIG. 2C illustrates a gap 216 between the outer surface 217 of the rotary manifold sleeve 208 and the rotary manifold recess 204. This gap 216 allows the rotary manifold sleeve 208 some movement within the pivot sleeve 200, although rotation is prevented by key 218.

FIG. 2D illustrates an exemplary shaft for use with the pivot sleeve 200, in the form of a pin 219. The pin 219 has fluid passages 220a and 220b between second ports 221a and 221 b in the side 222 of the pin 219 and third ports 223a and 223b respectively at or adjacent to one end 224 of the pin 219. While not seen in this view, the pin 219 has a further fluid passage, to provide a total of three.

Third port 223b is illustrated as entering from the side 222 of the pin 219 adjacent to the end 224, in order to allow a fitting (not illustrated) of sufficient size to be installed in addition to a fitting of similar dements in port 223a. For ease of manufacture, the fluid passage 220b is drilled from the end 224, and then blocked at point 225.

FIG. 2E illustrates an assembly 226 comprising the pivot sleeve 200 of FIG. 2A, the rotary manifold sleeve 208 of FIG. 2B, and the pin 219 of FIG. 2D. It may be seen that the seals 212a, 212b, 212c, and 212d act against the pin 219 to create annular chambers (227a, 227b, and 227c respectively) between the manifold bore (see 209 of FIG. 2B) and side 222 of the pin 219. The chambers 227a, 227b, and 227c axially align with first ports 221a, and 221 b (see FIG. 2D) and 221c, and hydraulic fittings 215a, 215b, and 215c respectively.

In use, as the pivot sleeve 200 rotates relative to the pin 219, the chambers (for example chamber 227c) allow fluid communication between the second ports (for example second port 221c) and first ports (for example first port 210c of FIG. 2B). The third ports (for example third port 223c) are provided with hydraulic hose fittings (not illustrated), to enable connection of hydraulic hoses (not illustrated).

FIG. 3A and FIG. 3B illustrate an exemplary drive wheel arm 300 generally configured in the manner of assembly 226. As with drive arm 226, pivot sleeve 301 may pivotally move about pin 302. Bushes (for example bush 303) are inserted into threaded portions (not illustrated but see, for example, threaded portions 206a and 206b of FIG. 2A) of the pivot sleeve 301 to support the pin 302 and retain the rotary manifold sleeve (not illustrated but see, for example, rotary manifold sleeve 208 of FIG. 2B). Pin 302 is fixed to the frame of the harvester head (for example, frame 8 of head 4 as illustrated in FIG. 1 B) by bolting retainer plate 304 to the frame. In doing so, the orientation of the pin 302 relative to the frame of the harvester head remains constant, allowing hard hydraulic fluid lines to be used in delivering hydraulic fluid to and from the drive wheel arm 300.

A retainer bolt 305 passes through the pivot sleeve 301 into the rotary manifold sleeve to key into and secure the manifold sleeve to the pivot sleeve 301. This prevents rotation of the parts relative to each other, which could misalign the apertures in the rotary manifold sleeve relative to the first ports in the pivot sleeve. Ears 306a and 306b extend from the pivot sleeve 301 , configured to receive a pin (not illustrated) to which a linear actuator such as a hydraulic cylinder (not illustrated) is pivotally coupled. Extension and retraction of the hydraulic cylinder causes the drive wheel arm 300 to be rotated about the pin 302 to open or close the arm 300 relative to a centreline of the harvester head, as known in the art.

A drive frame 307 extends from the pivot sleeve 301 , with side walls 308a and 308b and rear wall 309 forming a support structure for mounting plate 310. The mounting plate has a motor aperture 311 for receiving a rotary drive, for example a bi-directional orbital hydraulic motor (not illustrated), where it may be secured to the drive wheel arm 300.

A drive wheel is in turn mounted to the motor (for example as illustrated by RH feed wheel 11a and motor 14a of FIG. 1 B), and hydraulic hoses routed between the motor and hydraulic fittings (for example fittings 215a, 215b, and 215c of FIG. 2E).

The drive frame 307 has an opening between the side walls 308a and 308b. This allows access to the interior of the drive frame 307 for the installation and/or maintenance of the hydraulic motor and hosing between the motor and the first ports. A cover (not illustrated) may be secured to flange 312 to fully enclose the drive frame 307, protecting the motor and hosing.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.