Patent Application
20150289456
The present disclosure relates to a delimber of a knuckleboom loader and more particularly to a hydraulic arrangement for a delimber of a knuckleboom loader.
Knuckleboom loaders are used in forestry applications to process trees. Conventionally, knuckleboom loaders include a frame, a boom, a stick, and a grapple. One end of the boom is connected to the frame. The other end of the boom provides for connection with the stick. The grapple is located distally from the boom and connected at an opposing end of the stick. The boom and the stick allow positioning of the grapple relative to the frame while the grapple can be articulated about its connection with the stick. Further, the grapple may include one or more jaws that are operable to open or close while processing trees i.e., while picking or placing the trees from or at a specified location.
In some cases, the knuckleboom loaders are mounted on trailers and used in combination with delimbers. The delimbers have knives that remove branches from a trunk of a tree. The knuckleboom loaders typically include an accumulator and a pump therein. The accumulator is located between the pump and one or more actuators associated with the knives. During operation, the pump is driven by an engine of the knuckleboom loader. The pump charges the accumulator with pressurized fluid that can be used for moving the actuators to open and close the knives. However, when the engine and/or the pump is turned OFF, the accumulator may remain in the charged state and hence, continue to supply pressurized fluid into the actuators even after the engine and/or the pump has been turned OFF. This may cause the knives of the delimber to inadvertently close.
Some control systems have been developed in the past to control the operation of the actuators and/or the knives of the delimber. For example, U.S. Pat. No. 6,814,112 relates to a single-grip harvester head for felling and processing trees in which a controller controls the press-power of the knives on a tree. However, such control systems may not prevent the charged state of the accumulators i.e., after the engine and/or the pump being turned OFF, from inadvertently closing the knives. Moreover, use of previously known control systems in delimbers may cause the knives to grip the trunk of the tree and/or prevent free movement of the tree between the knives during the delimbing process. Therefore, the previously known control systems may be ineffective in operation besides being complicated and expensive to implement onto delimbers.
In one aspect, the present disclosure provides a knuckleboom loader for processing trees. The knuckleboom loader includes a delimber, an actuator, and a hydraulic arrangement. The delimber includes a knife. The actuator is coupled to the knife and is operable to move the knife. The hydraulic arrangement includes a fluid, a tank, a pump, and a valving arrangement. The tank is configured to store the fluid. The pump is in fluid communication with the tank and is configured to supply fluid from the tank to the actuator. The valving arrangement is located between the pump and the actuator. The valving arrangement is operable to regulate a flow of the fluid from the pump to the actuator, and from the actuator to the tank for opening and closing the knife relative to a trunk of a tree.
In another aspect, the present disclosure provides a delimbing system including a delimber, an actuator, a hydraulic arrangement, and a control module. The delimber includes a knife. The actuator is coupled to the knife and is operable to move the knife. The hydraulic arrangement includes a fluid, a tank, a pump, and a valving arrangement. The tank is configured to store the fluid. The pump is in fluid communication with the tank and is configured to supply fluid from the tank to the actuator. The pump is in fluid communication with the tank and is configured to supply fluid from the tank to the actuator. The valving arrangement is located between the pump and the actuator. The valving arrangement is operable to regulate a flow of the fluid from the pump to the actuator, and from the actuator to the tank. The control module is communicably coupled to the valving arrangement. The control module is configured to receive an input signal, and based on the input signal; command the valving arrangement for opening and closing the knife of the delimber relative to a trunk of a tree.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
The present disclosure relates to a hydraulic arrangement for a knuckleboom loader equipped with a delimber. Wherever possible the same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. Accordingly, it may be noted that any such reference to elements in the singular is also to be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims.
The knuckleboom loader 100 includes a prime mover 102 and a cab 104 mounted on the frame 103. As shown in
The prime mover 102 may be a fuel-based engine that powers the knuckleboom loader 100 by combustion of natural resources, such as gasoline, liquid natural gas, or other petroleum products. However, in alternative embodiments, the present disclosure may be equally implemented by way of using an electric motor in lieu of the engine.
The knuckleboom loader 100 further includes a boom 110, a stick 112, and a grapple 114 mounted in sequence to the frame 103. As such, the cab 104 and the boom 110 can be swiveled on top of the frame 103. Additionally, the boom 110 can be operated to pivot vertically with respect to the frame 103. The stick 112 can be vertically hoisted or lowered relative to the boom 110. The boom 110 and the stick 112 facilitate movement of the grapple 114 in various planes relative to the frame 103. Further, the grapple 114 can be articulated about its connection with the stick 112 thus, being capable of changing its orientation depending on specific requirements of an application. Therefore, the boom 110, the stick 112, and the grapple 114 impart dexterity to the knuckleboom loader 100 for executing operations such as loading and/or processing trees 101.
The knuckleboom loader 100 further includes a delimber 116 mounted at a second end 118 of the trailer 106. The delimber 116 includes a knife 120 (two knives 120a, 120b shown in the embodiment of
As depicted in
Referring now to
Turning back to
The valving arrangement 134 is located between the pump 132 and the actuator 122. The valving arrangement 134 is operable to regulate a flow of pressurized fluid from the pump 132 to the actuator 122, and from the actuator 122 to the tank 130 for moving the knives 120a, 120b relative to the trunk 101b of the tree 101
With reference to the specific embodiment of
The valve 136 is configured to allow pressurized fluid to be routed from the pump 132 to the actuator 122 in a first position 136a. Additionally, in this position, the valve 136 is also configured to allow fluid to be routed from the actuator 122 to the tank 130. As a result, the valve 136 causes the actuator 122 to extend and open the knives 120a, 120b.
However, when the valve 136 is moved into a second position 136b, pressurized fluid from the pump 132 can be routed to the actuator 122. Additionally, in the second position 136b, the valve 136 also allows fluid to be routed from the actuator 122 to the tank 130. Therefore, when in the second position 136b, the valve 136 may cause the actuator 122 to retract and effect a closing of the knives 120a, 120b.
Conversely, as shown in
Turning back to
By implementing the third position 136c of the valve 136 after the first position 136a, the actuator 122 may be held in the extended state to cause the knives 120a, 120b to remain in a fully open position. Similarly, by moving the valve 136 into the third position 136c after the second position 136b, the actuator 122 may be held in the retracted state to maintain the knives 120a, 120b in the fully closed position. The third position 136c of the valve 136 can also be beneficially implemented after the valve 136 has been in the first or second positions 136a, 136b for a brief period of time such that the actuator 122 is held partway between the fully extended and fully retracted positions. Consequently, the knives 120a, 120b are also maintained in the partly open or partly closed condition. As such, the amount of extension or retraction of the actuator 122 may determine an extent of opening or closing of the knives 120a, 120b.
As shown in
The operator may use the user-operable control 142 to command the control module 140 with the input signal S1. Based on the input signal S1, the control module 140 may change an operating state of the valving arrangement 134 to operatively open or close the knives 120a, 120b. For example, the operator may command the knives 120a, 120b of the delimber 116 to open by pressing a first switch on the user-operable control 142 and providing the control module 140 with the corresponding input signal S1. Similarly, the operator may command the knives 120a, 120b to be fully closed or simply maintained partway between the fully open and the fully closed positions via designated switches on the user-operable control 142.
As shown in
The control module 140 of the present disclosure is further configured to actuate the valving arrangement 134 and open the knives 120a, 120b of the delimber 116 if the measured fluid pressure Pfluid output by the sensor 144 is equal to the reference pressure Pref. To perform the delimbing process smoothly, the measured fluid pressure Pfluid should ideally be less than or equal to the reference pressure Pref. In an embodiment, the reference pressure Pref may be set to a value corresponding to a “touch-up” position of the knives 120a, 120b i.e., a position at which the knives 120a, 120b merely make contact with the trunk 101b without applying clamping force to the trunk 101b. If the reference pressure Pref is set at, for example, 10 psi (pounds per square inch), and if the measured fluid pressure Pfluid is less than the reference pressure Pref, say, for example, at 8 psi, the control module 140 determines that the knives 120a, 120b should be closed further in order to establish the “touch-up” position with the trunk 101b. Hence, the control module 140 allows the valve 136 to remain in the first position 136a until the measured fluid pressure Pfluid is equal to the reference pressure Pref.
When the measured fluid pressure Pfluid is equal to the reference pressure Pref, i.e., for e.g. 10 psi, the control module 140 determines that the knives 120a, 120b are currently in the “touch-up” position with the trunk 101b. Upon such determination, the control module 140 may, in one embodiment, actuate the valve 136 into the first position 136a for a brief period of time. Actuating the valve 136 into the first position 136a causes the knives 120a, 120b to be re-opened away from the trunk 101b. Further, as the first position 136a of the valve 136 is implemented for a brief period of time, the knives 120a, 120b can travel only to be located marginally away from the trunk 101b i.e., proximate to the trunk 101b. For example, when the valve 136 is moved to the first position 136a for the brief period of time, the knives 120a, 120b can travel backwards to 95% of its forward-travel relative to the trunk 101b of the tree 101. The control module 140 may then command the valve 136 into the third position 136c such that the knives 120a, 120b are held proximate to the trunk 101b i.e., without any contact with the trunk 101b.
Alternatively, when the measured fluid pressure Pfluid is equal to the reference pressure Pref, the control module 140 can optionally command the valve 136 to move directly into the third position 136a. Such movement of the valve 136 directly into the third position 136c can cause the knives 120a, 120b to be held in the “touch-up” position itself As such, in the “touch-up” position, the knives 120a, 120b can perform other additional and/or auxiliary functions such as, but not limited to, girdling and/or removing a bark of the tree 101. Therefore, the control module 140 of the present disclosure can either allow the knives 120a, 120b to be positioned close to the trunk 101b, or at the “touch-up” position with the trunk 101b depending on specific requirements of a logging application.
On the other hand, if the measured pressure Pfluid exceeds the reference pressure Pref, the control module 140 determines that the knives 120a, 120b are clamping the trunk 101b with substantial force. For example, if the fluid pressure Pfluid at the actuator 122, as measured by the sensor 144, is found to be 12 psi or 13 psi, then the control module 140 determines from the excess fluid pressure Pfluid that the knives 120a, 120b are currently clamping the trunk 101b of the tree 101 and/or preventing the grapple 114 from executing a pull-through movement of the tree 101 between the knives 120a, 120b. In such cases, the control module 140 is additionally configured to actuate the valve 136 into the first position 136a for relieving fluid pressure in the actuator 122. In one embodiment, the relief in fluid pressure may be continued until the knives 120a, 120b are moved into the “touch-up” position i.e., in contact with the trunk 101b of the tree 101 without any clamping force. However, in another embodiment, the fluid pressure may be relieved until the knives 120a, 120b are opened and positioned marginally away from the trunk 101b of the tree 101 i.e., where the knives 120a, 120b are only positioned proximate to the trunk 101b of the tree 101 without any make contact thereto.
Although the sensor 144 is disclosed herein, one of ordinary skill in the art will acknowledge that it is possible to contemplate other suitable structures and/or methods in lieu of the sensor 144 for the sensing of fluid pressure Pfluid. Some suitable structures and/or methods that can be alternatively implemented may include mechanical structures and/or hydraulic methods, but is not limited thereto.
Further, it is common knowledge that trees come in a variety of sizes and shapes. Moreover, in softwood logging applications, i.e. pertaining mostly to wood from pine and fir trees, it has been seen that a circumference of the trunk 101b typically decreases upwards or reduces gradually from a base 146 to a top portion 148 of the trunk 101b, i.e., the base 146 of the trunk 101b typically has a larger circumference or girth as compared to a top portion 148 of the trunk 101b.
Keeping this in mind, the control module 140 of the present disclosure is additionally configured to determine if the measured fluid pressure Pfluid is equal to the reference pressure Pref with a pre-specified frequency F as the tree 101 is being pulled between the knives 120a, 120b by the grapple 114. The value of pre-specified frequency F for executing such determination by the control module 140 may vary from one logging or harvesting application to another. In one embodiment, the control module 140 may be configured to receive the measured fluid pressure Pfluid and perform/repeat such determination with the reference pressure Pref at intervals of 0.3 seconds. However, a person of ordinary skill in the art will be able to determine a suitable periodicity or frequency F for a given forestry application to allow proper functioning of the control module 140.
Optionally, it is also envisioned that as the tree 101 is being pulled by the grapple 114 between the knives 120a, 120b, the control module 140 may continuously (i.e., without any intermittency) determine if the measured fluid pressure Pfluid is equal to the reference pressure Pref. Therefore, if the measured fluid pressure Pfluid at any instant of the delimbing process is equal to the reference pressure Pref, the control module 140 triggers the actuator 122 via the valve 136 into a movement of extension or retraction such that the knives 120a, 120b are moved marginally away or into the “touch-up” position with respect to the trunk 101b of the tree 101.
The reference pressure Pref is a value that is selected by a user or the manufacturer of the control module 140 depending on various factors of a logging application. Although the value of reference pressure Pref can vary from one logging application to another, it is envisioned that the reference pressure Pref could typically lie in the range of about 1 psi to 500 psi. However, for the purposes of understanding the present disclosure, the reference pressure Pref at the control module 140 may be regarded as being set at 10 psi. Prior to delimbing, the tree 101 is placed between the knives 120a, 120b and the knives 120a, 120b are momentarily brought into contact with the trunk 101b of the tree 101 until the fluid pressure Pfluid in the actuator 122 is measured and found to be equal to the reference pressure Pref. In doing so, the control module 140 affirmatively establishes that the knives 120a, 120b are in contact i.e., in the “touch-up” position with respect to the trunk 101b of the tree 101. Upon such determination, the control module 140 may, in one embodiment, command the actuator 122 to marginally open the knives 120a, 120b and hold the knives 120a, 120b at a position proximate to the trunk 101b of the tree 101. Alternatively, the control module 140 may command the actuator 122 to lock the knives 120a, 120b in the “touch-up” position itself. Therefore, the control module 140 prevents the fluid pressure Pfluid in the actuator 122 from exceeding the reference pressure Pref. Consequently, the knives 120a, 120b are prevented from clasping, clamping, or gripping the trunk 101b of the tree 101 during the delimbing operation.
As the tree 101 is being pulled between the knives 120a, 120b, the knives 120a, 120b may encounter a progressively narrower circumference of the trunk 101b. Accordingly, the control module 140, on the basis of the pre-specified frequency F, may repeatedly dispose the knives 120a, 120b in relative movement with the trunk 101b of the tree 101. Each time, the control module 140 determines if the measured fluid pressure Pfluid is equal to the reference pressure Pref i.e., for each contact made by the knives 120a, 120b with the trunk 101b. If the condition Pfluid=Pref (i.e., 10 psi) is satisfied, then the control module 140 may hold the “touch-up” position or optionally effect an opening of the knives 120a, 120b to a position marginally away from the trunk 101b, for example, to about 90% or 95% of the total forward travel relative to the trunk 101b of the tree 101.
In an embodiment, the valving arrangement 134 is configured to additionally prevent inadvertent closure the knives 120a, 120b when the prime mover 102 and/or the pump 132 are moved to a non-operational state. The non-operational state, disclosed herein, may be an OFF state of the engine and/or the pump 132 that is accomplished by the operator physically turning them OFF. Additionally, the non-operational state may also include situations where a breakdown of the engine and/or the pump 132 has occurred thus rendering the engine and/or the pump 132 unfit for further operation. The control module 140 may receive diagnostic data and/or operational state signals from various components of the knuckleboom loader 100 via appropriate secondary sensors for commanding the valving arrangement 134 into position to prevent closure of the knives 120a, 120b. The secondary sensors, disclosed herein, may be communicably coupled to the control module 140. Any type of sensor commonly known in the art may be used as the secondary sensor.
Further, a person having ordinary skill in the art will appreciate that in various embodiments of the present disclosure, the control module 140 may be readily embodied in the form of an ECM (Electronic Control module) package or a Programmable Logic Control (PLC) package and may be easily implemented for use with the knuckleboom loader 100. The ECM or PLC, disclosed herein, may further include various associated system hardware and/or software components known in the art.
Furthermore, although the present disclosure discloses that the delimber 116 forms part of the knuckleboom loader 100, the delimber 116 can optionally form part of a stand-alone delimbing system. Moreover, such stand-alone delimbing system can additionally include the hydraulic arrangement 128 and the control module 140 of the present disclosure for actuating the knives 120a, 120b of the delimber 116. One of ordinary skill in the art will appreciate that the delimbing process may be beneficially implemented by way of using the stand-alone delimbing system depending on specific requirements of a forestry application. Therefore, various combinations of the parts disclosed herein may be contemplated and such combinations can be implemented without deviating from the spirit of the present disclosure.
The delimber 116 of the present disclosure has applicability for implementation and use in industrial settings such as forestry, agriculture, construction and the like.
In some cases, the control module 140, disclosed herein, can be used to provide a controlled amount of clamping force by the knives 120a, 120b on the trunk 101b. In other cases, the control module 140 can altogether prevent the knives 120a, 120b from clamping, clasping, or gripping the tree 101 during the delimbing operation. Moreover, the control module 140 prevents the knives 120a, 120b from inadvertently closing when the engine and/or the pump is rendered into the non-operational state i.e., the OFF state. Although the valving arrangement 134 is configured to allow the knives 120a, 120b to intermittently make contact with the trunk 101b of the tree 101 i.e., until the the condition Pfluid=Pref is satisfied, such function is used by the control module 140 to affirmatively establish that the knives 120a, 120b are in contact or the “touch-up” position with the trunk 101b of the tree 101. Upon such determination, the control module 140 may hold the knives 120a, 120b in the “touch-up” position or alternatively configure the valve 136 into the first position 136a momentarily until such time that the knives 120a, 120b open to a position marginally away from the trunk 101b of the tree 101. As disclosed earlier herein, the degree or extent of such marginal opening may vary from one logging application to another. As such, the control module 140 configures the valve 136 into the third position 136c to maintain the “touch-up” position or the marginally open position of the knives 120a, 120b relative to the trunk 101b of the tree 101. When the knives 120a, 120b are moved marginally away from the trunk 101b or into the “touch-up” position with the trunk 101b, branches 101a of the tree 101 can be severed closer to the trunk 101b.
With reference to the foregoing embodiments, the knives 120a, 120b are held in the marginally-open position or the “touch-up” position until the control module 140 repeats the process of determining whether Pfluid=Pref at a subsequent location of the trunk 101b that is encountered from continuous movement of the tree 101 between the knives 120a, 120b. As disclosed earlier herein, the control module 140 may implement the pre-specified frequency F while repeatedly performing the process of determination of whether Pfluid=Pref.
With the present valving arrangement 134 and valving strategy associated thereof, the knuckleboom loader 100 can pull trees 101 freely through the delimber 116 to accomplish effective delimbing of the branches 101a by the knives 120a, 120b present therein. With use of the present control module 140, the knives 120a, 120b can be positioned to severe the branches 101a of the tree 101 without clamping the trunk 101b of the tree 101. Therefore, the knives 120a, 120b of the delimber 116 tend to be less prone to abrasion with the trunk 101b and a service life of the knives 120a, 120b is prolonged.
Moreover, with implementation of the present valving strategy in the knuckleboom loader 100, the knives 120a, 120b are configured to open or, if previously open, continue to remain in such open state when the engine and/or the pump 132 are turned OFF. In addition to this, during any event of abnormality in components of the knuckleboom loader 100, the valving strategy as defined by the control module 140 together with the valving arrangement 134 can prevent the knives 120a, 120b from inadvertently shutting or closing.
Moreover, the present configuration of the hydraulic arrangement 128, the control module 140, and the valving arrangement 134 allow a manufacturer to do away with use of accumulators that were typically employed by previously known control systems. As a result, costs associated with manufacture and operation of the present knuckleboom loader 100 can be less than that incurred with use of previously known systems. Moreover, the present configuration allows manufacturers of knuckleboom loaders and delimbing systems to achieve improved functionality with use of minimal components.
Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims.
