Feed assembly for wood reduction apparatus

An infeed assembly for a wood reduction apparatus that is selectively adjustable to feed waste into a wood reduction mill along different paths. In one embodiment, the infeed assembly includes at least one movable wall segment that is pivotally movable between extended and retracted positions. In the retracted position, the infeed assembly feeds wood waste into the mill along a path perpendicular. In the extended position, the infeed assembly feeds wood waste into the mill along an angled path. The wall segment may include a fixed end that is pivotally secured to the sidewall and a free end that is selectively movable into the infeed path to provide a surface directing the wood waste along an angled path into the mill. The infeed assembly may include two wall segments that are pivotally extendable into the infeed path from opposite sidewall. The two wall segments may pivot from opposite ends.

BACKGROUND OF THE INVENTION

The present inventions relates to wood reduction equipment and more particularly to feed assemblies for a wood reduction apparatus.

Various machines are available on the market for reducing waste wood, such as scrap timber, tree limbs and brush. One common type of wood reduction machine is a wood grinder. Grinders typically operate by essentially hammering wood into wood fragments in a hammermill. For example, a conventional grinder may include a hammermill with a rotating drum. The drum carries a plurality of hammers that protrude from the surface of the drum. In use, wood waste is fed into the rotating drum. As the waste passes into the swath of the hammers, it is battered into wood fragments. The wood fragments may be driven by the hammermill through grates. The size of the holes in the grates may be selected to assist in controlling the size of the resulting wood waste.

A typical grinder includes an infeed assembly that delivers wood waste to the hammermill. For example, a conventional infeed assembly moves wood into a hammermill in a direction perpendicular to the axis of rotation of the hammermill. Because wood waste often includes brush, limbs and other waste that is most easily fed into the feed assembly in random piles or clumps, it is typically desirable to provide the grinder with a wide hammermill and a wide feed assembly that can accommodate wide piles or clumps of waste. Narrower feed system can require small piles or clumps and therefore may slow down feeding and operation of the grinder.

SUMMARY OF THE INVENTION

It has been determined that a hammermill will typically operate more efficiently when wood waste is fed into the hammermill at an angle to the longitudinal extent of the wood fibers. The wood grinding operation reduces wood waste principally through a combination of separating and shearing (e.g. cutting) wood fibers. Fiber shearing typically requires more force than fiber separation. Because wood fibers are typically extended along the length of a piece of wood, the amount of fiber shearing versus the amount of fiber separation will typically vary depending on the angle at which the wood item is fed into the hammermill. When the wood is fed perpendicularly into the hammermill, the ability of the hammers to separate the wood fibers is relatively limited and the hammers are required to shear a relatively large percentage of the wood fibers. When logs or other similar items are fed into the hammermill at an angle, the hammers typically have the ability to separate a larger percentage of the wood fibers and therefore require less wood shearing. Accordingly, less horsepower is generally required to grind logs fed into the hammermill at an angle than would be required if the logs were feed perpendicularly into the hammermill.

With limbs, brush and random clumps or piles of waste material, a conventional feed system will generally feed the waste into the hammermill so that individual items engage the hammermill in random orientations. This typically results is reasonably efficient operation for random clumps or piles. On the other hand, a conventional feed system will typically feed longer pieces of wood waste, such as logs and longer tree limbs, perpendicularly into the hammermill. This will typically require the hammermill to shear a relatively large percentage of the wood fibers and therefore require increased horsepower. Accordingly, a conventional wood reduction apparatus may not provide optimal performance with longer tree limbs and other similar items of waste that are typically fed perpendicularly into the hammermill.

The present invention provides a wood reduction apparatus with an adjustable feed system that is selectively adjustable to allow waste to be selectively directed into the mill along a perpendicular path or an angled path with respect to the mill. In one embodiment, the feed system includes a feed conveyor and a pair of sidewalls oriented perpendicularly to a hammermill. In this embodiment, the feed system includes at least one wall segment that is selectively pivotal to provide an angled wall that feeds wood waste in the mill at angle rather than perpendicularly. In one embodiment, the wall segment is selectively pivotal into the space over the feed conveyor.

In one embodiment, the wall segment includes a fixed end that is pivotally secured to the sidewall and a free end that is movable away the sidewall through operation of an actuator. In one embodiment, the actuator is a linear actuator, such as a hydraulic cylinder, coupled to a hinged arm assembly.

In one embodiment, the feed system includes a pair of wall segments that are selectively pivotal into the space over the feed conveyor from opposite sidewalls. The two wall segments may be mounted directly opposite one another on opposite sidewalls. The two wall segments may pivot from opposites ends so that they cooperatively define a feed space that extends at angle with respect to the mill.

The present invention provides a simple and effective structure that permits an infeed assembly to selectively feed wood waste into the mill in a direction perpendicular to the mill or in a direction that is angled with respect to the mill. This permits the infeed assembly to be selectively adjusted to the feed direction most suitable for the type of wood waste being fed into the wood reduction apparatus. Use of the present invention may reduce the horsepower required to reduce certain waste while maintaining relatively high flow through rates by permitting adjustment to the greatest possible infeed width.

DESCRIPTION OF THE CURRENT EMBODIMENT

A wood grinder incorporating a feed assembly in accordance with the present invention is shown inFIG. 1. The wood grinder10generally includes a superstructure12, an infeed assembly14, a hammermill18, an engine assembly20and an output conveyor22. The hammermill18extends laterally across the superstructure12and is rotatably driven by the engine assembly20. The infeed assembly14extends longitudinally along the superstructure to feeding wood waste into the hammermill18in a direction perpendicular to the axis of the hammermill18. The infeed assembly14generally includes a bed24fitted with a plurality of feed chains54a-d. The bed24defines a generally horizontal surface to receive and support wood waste. The feed chains54a-dare power driven to move waste placed on the bed24into the hammermill18. The superstructure12includes sidewalls50,52that extend upwardly along opposite sides of the bed24to hold wood waste on the bed24. The sidewalls50,52extend generally perpendicularly to axis of the hammermill18. In this embodiment, each sidewall50,52includes a movable wall segment70,72that can be selectively pivoted into the space over the bed24to define a surface for shepherding wood waste into the hammermill18at an angle to axis of the hammermill18. The wall segments70,72may pivot at opposite ends so that they remain substantially parallel when pivoted. In use, the wall segments70,72may be retracted to provide an infeed assembly14that moves wood waste into the hammermill18in a direction perpendicular to the axis of the hammermill18(See arrow A inFIG. 1). Alternatively, the wall segments70,72may be extended to provide an infeed assembly14that moves wood waste into the hammermill18at an angle to the axis of the hammermill18(See arrow B inFIG. 9).

II. Wood Reduction Apparatus

For purposes of disclosure and not by way of limitation, the present invention is described in connection with a wood reduction apparatus that is generally identical to the Morbark Model 3800 Wood Hog, which is available from Morbark, Inc. of Winn, Mich. The Morbark Model 3800 Wood Hog Parts Manual is incorporated herein by reference in its entirety. The illustrated wood hog includes a stacked-plate rotor with removable hammer inserts. The illustrated wood hog includes a variety of optional features and components that are not necessary for implementation of the present invention. The present invention is not limited to use on or in connection with this specific wood hog or the specific rotor shown in the illustrations. To the contrary, the various features and aspects of the present invention are well suited for incorporation into a wide variety of wood reduction machines and a wide variety of rotors. For example, the present invention may be incorporated into essentially any wood reduction apparatus in which it may be desirable to selectively change the orientation at which materials are fed into the mill.

A wood reduction apparatus10in accordance with an embodiment of the present invention is shown inFIGS. 1-12. The wood reduction apparatus10is generally conventional (except as described herein) and therefore not described in detail. However, to facilitate an understanding of the present invention in the context of the illustrated embodiment, a brief overview is provided of the wood reduction apparatus and its operation. The illustrated wood reduction apparatus10generally includes a superstructure12, an infeed assembly14, a yoke assembly16, a hammermill18, an engine assembly20and an output conveyor22. The infeed assembly14is mounted on the superstructure12and provides a mechanism for feeding wood waste into the hammermill18. The infeed assembly14is described in more detail below, but for purposes of gaining a general understanding of the wood reduction apparatus, generally includes a bed24that is fitted with feed chains54a-d(SeeFIGS. 11 and 12). The feed chains54a-dare supported by the bed24and are power driven in a manner that moves the wood waste placed onto the bed24into the hammermill18. The feed chains54a-dmay be driven by a motor (not shown). The motor may be variable speed to allow control over the speed at which wood waste is fed into the hammermill18. The yoke assembly16includes a feed drum28that assists in shepherding wood waste into the hammermill18. The yoke assembly16is pivotally mounted to superstructure12so that it can pivot up and down to accommodate wood waste of varying heights. For example, the yoke assembly16pivots up and down to permit the feed drum28to ride up and down over wood waste as it is moved under the feed drum28into the hammermill18. The yoke assembly16may include a hydraulic cylinder (or other suitable mechanism) for applying an appropriate downward force on the feed drum28. The feed drum28may be driven by a motor (not shown). The motor may be variable speed to allow control over the speed at which wood waste is fed into the hammermill18. If power driven, the speed of the feed drum28may be synchronized with the speed of the feed chains54a-d.

Referring now toFIGS. 2 and 3, the hammermill18is mounted within a base assembly30. In the illustrated embodiment, the base assembly30generally includes a substructure42supporting an anvil32, a hood34and a plurality of grates36. The hammermill18is rotatably mounted to the substructure42. The hammermill18is configured for upward rotation with respect the infeed side (i.e. the side on which wood waste is fed into the hammermill18). Referring now toFIG. 3, the anvil32is mounted to the substructure42just above the hammermill18. The spacing between the anvil32and hammermill18may vary, but is typically around ¼thof an inch. The grates36are mounted to the substructure42around the hammermill18(SeeFIG. 2, which shows the hammermill18removed from the base assembly30). As perhaps best shown inFIG. 3, the grates36are curved to closely match the outer diameter of the hammermill18. The spacing between the hammermill18and the grates36may correspond with the anvil spacing, but that is not strictly necessary. In operation, the hammermill18drives the wood waste upwardly hammering it into the anvil32and the grates36. The wood waste is first reduced through interaction between the hammers102on the hammermill18and the anvil32. The wood fragments are driven past the anvil32into the space between the hammermill18and the grates36. The continued hammering action of the hammermill18further reduces the wood waste until it is driven through the openings in the grates36. The reduced wood falls onto an intermediate conveyor38(typically a belly conveyor) extending below the hammermill18(SeeFIG. 3). The intermediate conveyor38transports the output to an inclined conveyor22(SeeFIG. 1) that lifts the output to facilitate piling. Given that the ground wood is forced into the space between the hammermill18and the anvil and through the grates36, the size of the ground output is dictated in part by the anvil spacing and the size of the openings in the grates36. The engine assembly20, directly or indirectly, provides power to the various driven components of the wood reduction apparatus10. For example, the engine assembly20drives the hammermill18through an arrangement of belts (not shown). As another example, the engine assembly20may drive one or more hydraulic pumps (not shown) that can be used to operate hydraulic components.

As noted above, the wood grinder10includes an infeed assembly14having a bed24fitted with feed chains54a-dthat are power driven t move wood waste into the hammermill18. The bed24of the illustrated embodiment generally includes a substantially horizontal surface configured to support the feed chains54a-d. The bed24may be covered with wear components60that form the interface between the feed chains54a-dand the bed24. The wear components60may be sheets of metal or may be manufactured from low friction wear materials. The bed24maybe divided by dividers62a-cinto separate tracks64a-d—one between each pair of adjacent feed chain54a-d. In the illustrated embodiment, the infeed assembly14includes four feed chains54a-darranged side-by-side along the bed24. In this embodiment, each feed chain54a-dis slidably positioned into a corresponding track64a-din the bed24. The dividers62a-dhelp to hold the chains54a-din their respective tracks64a-band to reduce the possibility of unwanted interaction between adjacent chains54a-d. The feed assembly14includes a feed chain drive assembly66. The feed chain drive assembly66generally includes a drive shaft (not shown) carrying a plurality of drive sprockets (not shown), an idler shaft56carrying a plurality of the idler wheels58and a drive motor (not shown) coupled to the drive shaft. The drive shaft (not shown) and idler shaft56are disposed at opposite longitudinal ends of the bed24. The feed chains54a-dextend around the drive sprockets at one end and around idler wheels at the other. The drive shaft is coupled to a drive motor (not shown) so that movement of the chains54a-dis achieved through movement of the drive motor. The drive motor (not shown) may be coupled to the drive shaft (not shown) using a gear assembly (not shown) that provides the desired combination of torque and speed. The drive motor (not shown) may be essentially any motor capable of providing sufficient torque to move the feed chains54a-dand the material carried by the chains54a-d, such as a hydraulic motor or an electric motor. If desired, the drive motor (not shown) may be operated by a control system that allows manual and/or automatic control over the speed and direction of the feed chains54a-d. Although the illustrated embodiment includes feed chains, the infeed assembly14may alternatively include one or more feed belts or other mechanisms capable of moving wood waster over the bed24into the hammermill18.

Referring now toFIGS. 4-5and11-12, the superstructure12includes sidewalls50,52that extend upwardly along both sides of the bed24to retain wood waste on the bed24. In the illustrated embodiment, the sidewalls50,52are generally planar and extend substantially vertically along the entire length of the bed24. The height of the sidewalls50,52may vary from application to application, but is typically selected to provide sufficient height to retain wood waste on the bed24. The construction of the sidewalls50,52may vary from application to application. However, in the illustrated embodiment, the sidewalls50,52include a plurality of generally flat panels, such as sheet metal, mounted to a vertical framework, such as a grid-work of steel tubes.

As shown inFIGS. 7-10and12, each sidewall50,52includes a movable wall segment70,72that is movable to vary the angle at which wood waste is fed into the hammermill18. The wall segments70,72of the illustrated embodiment extend longitudinally through a substantial portion of the length of the bed24. The length of the wall segments70,72may, however, vary from application to application as desired. In the illustrated embodiment, the wall segments70,72are essentially identical except that they are oriented in opposite directions (SeeFIG. 9). Accordingly, only a single wall segment70will be described in detail. Wall segment70generally includes a frame90and a panel92. The frame90includes a pair of horizontal supports94a-bthat extend essentially the full length of the wall segment70. The size, shape, number and configuration of the horizontal supports94a-bmay vary from application to application to provide the desired strength and support for the wall segment70. As perhaps best seen through comparison ofFIGS. 1 and 7, wall segment70has a fixed end74that is pivotally mounted to the sidewall50and a free end76that is coupled to an actuator82. Although the pivot structure may vary, in this embodiment, the fixed end of the wall segment70is mounted to the superstructure12by a barrel hinge96. The wall segment70may include a pair of sleeves98a-bfixed to the ends of horizontal supports94a-b, for example, by welding. The superstructure12may include three sleeves100a-cconfigured to interfit with the wall segment sleeves98a-b. For example, the three sleeves100a-cmay be welded or otherwise secured to a vertical support in the vertical framework of the sidewall50with spacing appropriate to closely receive the wall segment sleeves98a-b. A hinge pin102(SeeFIG. 9) may be fitted within the sleeves98a-band100a-cto pivotally interconnect the wall segment70with the superstructure12. The hinge pin102may be secured in place, for example, by a cotter pin, snap ring or similar component. In the illustrated embodiment, the free end of the wall segment70is pivotally secured to the actuator82so that the free end of the wall segment70may be moved by operation of the actuator82. In this embodiment, the wall segment70includes a clevis assembly114. As described in more detail below, the actuator82of the illustrated embodiment includes a linkage110that is coupled to the clevis assembly114to allow the actuator82to pivot the wall segment70into the space over the bed24.

As perhaps best shown inFIG. 12, the bottom edge of the wall segment70is higher than the top surface of the feed chains54a-dso that the wall segment70can be pivoted out into the space above the feed chains54a-dwithout interference from the feed chains54a-d. The spacing between the bottom edge of the wall segment70and the top of the feed chains54a-dmay vary from application to application depending in part on the range of vertical motion (e.g. bouncing) in the feed chains54a-dduring operation. If desired, a flap or skirt (not shown) may extend from the bottom edge of the wall segment70to the top surface of the feed chains54a-dto close the gap. The flap or skirt (not shown) may be a flexible material, such as a strip of durable rubber or plastic.

As noted above, the infeed assembly14includes a pair of actuators82for moving the wall segments70,72between the retracted and extended positions (SeeFIGS. 6A,6B,7A and7B). In the illustrated embodiment, each sidewall50,52includes a separate actuator82, but a single actuator operatively coupled to both sidewalls50,52may be used in some applications. In the illustrated embodiment, the actuators82are essentially identical except that they are oriented in opposite directions. Accordingly, only a single actuator82will be described in detail. Although only the actuator82operating wall segment70will be described in detail,FIGS. 5 and 10show the actuator82of wall segment72. The reference numerals used in connection with the detailed description of wall segment70and its actuator82are used to identify like (but generally minor image) components inFIGS. 5 and 10.

The actuator82of the illustrated embodiment generally includes a linear actuator108and a linkage110. The linkage110is connected between a fixed point on the superstructure12and the free end76of the wall segment70so that operation of the linkage110results in movement of the free end76with respect to the superstructure12. In the illustrated embodiment, the linear actuator108is a generally conventional double-acting hydraulic cylinder, but it could be essentially any other actuator (liner or non-linear) capable of operating the linkage110to move the wall segment70between extended and retracted positions. The illustrated linkage110is a hinge linkage, but it could be essentially any linkage that is capable of translating movement of the linear actuator108into movement of the wall segment70. The hinge linkage110generally includes an inner arm130and an outer arm132that are pivotally joined along a hinge134. The inner arm130includes upper and lower hinge bars136,138that are coupled by a plate140. The inner arm130terminates in a pin eye117. The inner arm pin eye117is coupled to the clevis assembly121on the sidewall50by a pin147. The pin147allows the inner arm130to pivot with respect to the sidewall clevis assembly121during operation of the actuator82. Similarly, the outer arm132includes upper and lower hinge bars142and144that are coupled by a plate146. Like the inner arm130, the outer arm132terminates in a pin eye116. The pin eye116is coupled to the clevis assembly114on the wall segment70by a pin146. The pin146allows the outer arm132to pivot with respect to the wall segment70during operation of the actuator82.

The hydraulic cylinder108is pivotally connected between a fixed point on the superstructure12and the hinge134of the linkage110. More specifically, one end of the hydraulic cylinder108is connected to a clevis120or other mounting structure affixed to the superstructure12. The clevis120may be a flange-mounted clevis that is welded or otherwise secured to a vertical support in the sidewall vertical framework. The hydraulic cylinder108of the illustrated embodiment includes a pin eye118that is secured to the clevis120by a clevis pin122. The opposite end of the hydraulic cylinder108in the illustrated embodiment is directly secured to the hinge pin124of the linkage110. As shown, the rod126of the hydraulic cylinder108terminates in a rod eye128. The hinge pin124is fitted through the rod eye128to intersecure the hydraulic cylinder108and the linkage110.

Although the infeed assembly14of the illustrated embodiment includes a pair of movable wall segments70,72, the infeed assembly may include only a single movable wall segment. For example, in some applications, movable wall segment70may be eliminated leaving only a single movable wall segment (e.g. wall segment72) angling inwardly toward the hammermill18.

The actuators82, and consequently the position of the wall segments70,72, may be controlled by an automated control system (not shown). For example, a control button or other operator input device (e.g. key board, touch screen or mouse) may be used to direct a control computer to extend or retract the wall segments70,72. A single input may be used to dictate the position of both wall segments70,72. In this embodiment, the control computer extends/retracts both wall segments70,72in response to a single operator input. Alternatively, control over the wall segments70,72may be segregated so that a separate operator input is required for each wall segment70,72. As an alternative to the automated system, the wall segments70,72may be operated through manual operation of appropriate controls. For example, each hydraulic cylinder may be extended and retractor through manual operation of a corresponding conventional hydraulic control valve. In this alternative, an operator may manually operate a 4-way hydraulic valve coupled to the hydraulic cylinders108to extend or retract the wall segments70,72. A single hydraulic valve may be used to control both hydraulic cylinders, or separate valves may be used to separately control the cylinders. In yet another alternative embodiment, the wall segments70,72may be manually extended and retracted. In this embodiment, the hydraulic cylinders may be eliminated and the wall segments70,72may be manually moved into the correct position and locked in place, for example, by locking the linkage in the desired position.