BACKGROUND
The present disclosure is directed toward power machines and power machine implements. More particularly, the present disclosure is related to implements, and power machines with implements, that have implement protection mechanisms.
Power machines, for the purposes of this disclosure, include any type of machine that generates power for the purpose of accomplishing a particular task or a variety of tasks. One type of power machine is a work vehicle. Work vehicles are generally self-propelled vehicles that have a work device, such as a lift arm (although some work vehicles can have other work devices) that can be manipulated to perform a work function. Work vehicles include loaders, excavators, utility vehicles, tractors, and trenchers, to name a few examples.
A work device on a power machine may be equipped with an attachment or implement for performing various work functions. One exemplary attachment or implement is a landplane, which is a land planning tool that breaks up hard ground and levels surfaces, removes large clods and rocks while leveling and grading and peels sod or acrates soil for seeding. The landplane attachment or implement may include a scarifier that may be lowered to break up hard soil or may be raised when not needed.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
SUMMARY
This summary and the abstract are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. The summary and the abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter.
An implement on a power machine includes at least first and second auxiliary couplers configured to be coupled to a source of hydraulic fluid on the power machine, a hydraulic actuator having a base end coupled to the first auxiliary coupler and a rod end coupled to the second auxiliary coupler and a protection mechanism that is configured to receive hydraulic fluid during normal retraction and extension of the hydraulic actuator. When an unintended external tension force causes the hydraulic actuator to forcibly extend, the protection mechanism is configured to provide hydraulic fluid to the base end of the hydraulic actuator. When an unintended external compression force causes the hydraulic actuator to forcibly retract, the protection mechanism is configured to receive excess hydraulic fluid from the base end.
A power machine includes a frame, tractive elements supporting the frame, an implement coupled to the frame and having a tool, a hydraulic actuator coupled to the tool and at least first and second hydraulic lines and a protection mechanism. The hydraulic actuator includes a base end coupled to the first hydraulic line and a rod end coupled to a second hydraulic line. The protection mechanism is configured to receive hydraulic fluid during normal retraction and extension of the hydraulic actuator. When an unintended external tension force causes the hydraulic actuator to forcibly extend, the protection mechanism is configured to provide hydraulic fluid to the base end of the hydraulic actuator. When an unintended external compression force causes the hydraulic actuator to forcibly retract, the protection mechanism is configured to receive excess hydraulic fluid from the base end.
An implement on a power machine includes a tool having a rotatable bar, a hydraulic actuator having a base end and a rod end and being coupled to the tool and a protection mechanism coupled to the rotatable bar of the tool and to the hydraulic actuator. The protection mechanism is configured to be in a stationary position during normal operation of the tool and in a tripped position upon an occurrence of a high force event exceeding a threshold torque on the protection mechanism. The protection mechanism includes one or more spring-loaded trip plates that rotate relative to each other in response to the high force event so that the rotatable bar of the tool is temporarily decoupled from the hydraulic actuator and is allowed to rotate without causing the hydraulic actuator to forcibly extend or forcibly retract.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating the basic systems of a power machine upon which disclosed embodiments may be incorporated.
FIG. 2 is a block diagram illustrating basic systems of the power machine of FIG. 1 as are relevant to interact with an implement upon which disclosed embodiments may be incorporated.
FIG. 3 is a perspective view of an exemplary landplane implement with a scarifier in a lowered position according to an embodiment.
FIG. 4 is a perspective view of a protection mechanism illustrated in FIG. 3 according to an embodiment
FIG. 5 is an exploded view of the protection mechanism illustrated in FIG. 4.
FIG. 6 is a section view of the landplane implement taken through the section line illustrated in FIG. 3 according to an embodiment.
FIG. 7 is a section view of the landplane implement of FIG. 6 but with the scarifier in a raised position according to an embodiment.
FIG. 8 is a section view of the landplane implement of FIG. 6 but with the scarifier in a lowered, reversed position according to an embodiment.
FIG. 9 is a section view of the protection mechanism taken through the section line illustrated in FIG. 4 with the protection mechanism in a stationary position according to an embodiment.
FIG. 10 is a section view of the protection mechanism of FIG. 4 with the protection mechanism in a tripped position according to an embodiment.
FIG. 11 is a perspective view of a landplane implement with a scarifier in a lowered position according to another embodiment.
FIG. 12 is a section view of the landplane implement taken through the section line illustrated in FIG. 11 according to an embodiment.
FIG. 13 is a section view of the landplane implement of FIG. 12 but with the scarifier in a raised position according to an embodiment.
FIG. 14 is a section view of the landplane implement of FIG. 12 but with the scarifier in a raised, reversed position according to an embodiment.
FIG. 15 is a section view of the landplane implement of FIG. 12 but with the scarifier in a raised, reversed position according to an embodiment.
FIG. 16 is a schematic diagram of one embodiment of a hydraulic circuit including a protection mechanism and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a raised position.
FIG. 17 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 16 and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a lowered position.
FIG. 18 is a schematic diagram of one embodiment the hydraulic circuit including the protection mechanism in FIG. 16 and illustrating an occurrence of an external force event that causes a forced extension of the hydraulic actuator and therefore forced raising of the scarifier in FIG. 11.
FIG. 19 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 16 and illustrating an occurrence of an external force event that causes forced retraction of the hydraulic actuator and therefore forced lowering of the scarifier in FIG. 11.
FIG. 20 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 16 and illustrating the scarifier in FIG. 11 contacting an immovable object when the scarifier is in the raised position.
FIG. 21 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 16 and illustrating the scarifier in FIG. 11 contacting an immovable object when the scarifier is in the lowered position.
FIG. 22 is a schematic diagram of another embodiment of a hydraulic circuit including an protection mechanism and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a raised position.
FIG. 23 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 22 and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a lowered position.
FIG. 24 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 22 and illustrating an occurrence of an external force event that causes a forced extension of the hydraulic actuator and therefore the forced raising of the scarifier in FIG. 11.
FIG. 25 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 22 and illustrating an occurrence of an external force event that causes forced retraction of the hydraulic actuator and therefore the forced lowering of the scarifier in FIG. 11.
FIG. 26 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 22 and illustrating the scarifier in FIG. 11 contacting an immovable object in the raised position.
FIG. 27 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 22 and illustrating the scarifier in FIG. 11 contacting an immovable object when in the lowered position.
FIG. 28 is a schematic diagram of another embodiment of a hydraulic circuit including a protection mechanism and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a raised position.
FIG. 29 is a schematic diagram of one embodiment of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating the hydraulic actuator in FIG. 11 actuating the scarifier in a lowered position.
FIG. 30 is a schematic diagram of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating an occurrence of an external force event that causes forced extension of the hydraulic actuator and therefore the forced raising of the scarifier in FIG. 11 under one embodiment.
FIG. 31 is a schematic diagram of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating an occurrence of an external force event that causes forced retraction of the hydraulic actuator and therefore the forced lowering of the scarifier in FIG. 11 under one embodiment.
FIG. 32 is a schematic diagram of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating the scarifier in FIG. 11 contacting an immovable object when in the raised position under one embodiment.
FIG. 33 is a schematic diagram of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating the scarifier in FIG. 11 contacting an immovable object when in the lowered position under one embodiment.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
The concepts disclosed in this discussion are described and illustrated with reference to exemplary embodiments. These concepts, however, are not limited in their application to the details of construction and the arrangement of components in the illustrative embodiments and are capable of being practiced or being carried out in various other ways. The terminology in this document is used for the purpose of description and should not be regarded as limiting. Words such as “including,” “comprising,” and “having” and variations thereof as used herein are meant to encompass the items listed thereafter, equivalents thereof, as well as additional items.
Disclosed embodiments include implement protection control to prevent damage to one or more actuators or mechanisms which operate a tool on an implement. For example, a landplane implement may include a scarifier for performing various landscape preparation tasks including grading and leveling, peeling sod and scarifying. The scarifier is configured to be in a lowered position or a raised position depending on whether the scarifier is needed during landscape preparation activities. In one embodiment, the lowering and raising of the scarifier may be actuated by one or more hydraulics. These one or more hydraulic actuators are susceptible to damage should teeth of the scarifier contact a large object, such as a boulder or concrete, during operation, or if the power machine is operated in a direction that is opposite of a direction of operation for the particular direction to which the teeth of the scarifier are oriented. In addition, the frame and components of the scarifier are also susceptible to damage.
These concepts can be practiced on various power machines, as will be described below. A representative power machine on which the embodiments can be practiced is illustrated in diagram form in FIG. 1 and described below before any embodiments are disclosed. Power machines, for the purposes of this discussion, include a frame, at least one work element, and a power source that is capable of providing power to the work element to accomplish a work task. One type of power machine is a self-propelled work vehicle. Self-propelled work vehicles are a class of power machines that include a frame, work element, and a power source that is capable of providing power to the work element. At least one of the work elements is a motive system for moving the power machine under power.
FIG. 1 is a block diagram illustrating the basic systems of a power machine 100 upon which the embodiments discussed below can be advantageously incorporated and can be any of a number of different types of power machines. The block diagram of FIG. 1 identifies various systems on power machine 10 and the relationship between various components and systems. As mentioned above, at the most basic level, power machines for the purposes of this discussion include a frame, a power source, and a work element. The power machine 10 has a frame 11, a power source 12, and a work element 13. Because power machine 10 shown in FIG. 1 is a self-propelled work vehicle, it also has tractive elements 14, which are themselves work elements provided to move the power machine over a support surface and an operator station 15 that provides an operating position for controlling the work elements of the power machine. A control system 16 is provided to interact with the other systems to perform various work tasks at least in part in response to control signals provided by an operator.
Certain work vehicles have work elements that are capable of performing a dedicated task. For example, some work vehicles have a lift arm to which an implement such as a bucket is attached such as by a pinning arrangement. The work element, i.e., the lift arm can be manipulated to position the implement for the purpose of performing the task. The implement, in some instances can be positioned relative to the work element, such as by rotating a bucket relative to a lift arm, to further position the implement. Under normal operation of such a work vehicle, the bucket is intended to be attached and under use. Such work vehicles may be able to accept other implements by disassembling the implement/work element combination and reassembling another implement in place of the original bucket. Other work vehicles, however, are intended to be used with a wide variety of implements and have an implement interface such as implement interface 17 shown in FIG. 1. At its most basic, implement interface 17 is a connection mechanism between the frame 11 or a work element 13 and an implement, which can be as simple as a connection point for attaching an implement directly to the frame 11 or a work element 13 or be more complex, as discussed below.
On some power machines, implement interface 17 can include an implement carrier, which is a physical structure movably attached to a work element. The implement carrier has engagement features and locking features to accept and secure any of a number of implements to the work element. One characteristic of such an implement carrier is that once an implement is attached to it, it is fixed to the implement (i.e., not movable with respect to the implement) and when the implement carrier is moved with respect to the work element, the implement moves with the implement carrier. The term implement carrier as used herein is not merely a pivotal connection point, but rather a dedicated device specifically intended to accept and be secured to various different implements. The implement carrier itself is mountable to a work element 13 such as a lift arm or the frame 11. Implement interface 17 can also include one or more power sources for providing power to one or more work elements on an implement. Some power machines can have a plurality of work element with implement interfaces, each of which may, but need not, have an implement carrier for receiving implements. Some other power machines can have a work element with a plurality of implement interfaces so that a single work element can accept a plurality of implements simultaneously. Each of these implement interfaces can, but need not, have an implement carrier.
Frame 11 includes a physical structure that can support various other components that are attached thereto or positioned thereon. The frame 11 can include any number of individual components. Some power machines have frames that are rigid. That is, no part of the frame is movable with respect to another part of the frame. Other power machines have at least one portion that is capable of moving with respect to another portion of the frame. For example, excavators can have an upper frame portion that rotates with respect to a lower frame portion. Other work vehicles have articulated frames such that one portion of the frame pivots with respect to another portion for accomplishing steering functions.
Frame 11 supports the power source 12, which is capable of providing power to one or more work elements 13 including the one or more tractive elements 14, as well as, in some instances, providing power for use by an attached implement via implement interface 17. Power from the power source 12 can be provided directly to any of the work elements 13, tractive elements 14, and implement interfaces 17. Alternatively, power from the power source 12 can be provided to a control system 16, which in turn selectively provides power to the elements that capable of using it to perform a work function. Power sources for power machines typically include an engine such as an internal combustion engine and a power conversion system such as a mechanical transmission or a hydraulic system that is capable of converting the output from an engine into a form of power that is usable by a work element. Other types of power sources can be incorporated into power machines, including electrical sources such as electrical motors or a combination of power sources, known generally as hybrid power sources.
FIG. 1 shows a single work element designated as work element 13, but various power machines can have any number of work elements. Work elements are typically attached to the frame of the power machine and movable with respect to the frame when performing a work task. In addition, tractive elements 14 are a special case of work element in that their work function is generally to move the power machine 10 over a support surface. Tractive elements 140 are shown separate from the work element 13 because many power machines have additional work elements besides tractive elements, although that is not always the case. Power machines can have any number of tractive elements, some or all of which can receive power from the power source 12 to propel the power machine 10. Tractive elements can be, for example, track assemblies, wheels attached to an axle, and the like. Tractive elements can be mounted to the frame such that movement of the tractive element is limited to rotation about an axle (so that steering is accomplished by a skidding action) or, alternatively, pivotally mounted to the frame to accomplish steering by pivoting the tractive element with respect to the frame.
Power machine 10 includes an operator station 15 that includes an operating position from which an operator can control operation of the power machine. In some power machines, the operator station 15 is defined by an enclosed or partially enclosed cab. Some power machines on which the disclosed embodiments may be practiced may not have a cab or an operator compartment of the type described above. For example, a walk behind loader may not have a cab or an operator compartment, but rather an operating position that serves as an operator station from which the power machine is properly operated. More broadly, power machines other than work vehicles may have operator stations that are not necessarily similar to the operating positions and operator compartments referenced above. Further, some power machines such as power machine 10 and others, whether or not they have operator compartments or operator positions, may be capable of being operated remotely (i.e., from a remotely located operator station) instead of or in addition to an operator station adjacent or on the power machine. This can include applications where at least some of the operator controlled functions of the power machine can be operated from an operating position associated with an implement that is coupled to the power machine. Alternatively, with some power machines, a remote control device can be provided (i.e., remote from both of the power machine and any implement to which is it coupled) that is capable of controlling at least some of the operator controlled functions on the power machine.
Disclosed embodiments can be practiced on various implements and various power machines. Representative implement 18, of which the embodiments may be practiced and representative power machine 10 to which the representative implement may be operably coupled are illustrated in diagram form in FIG. 2. For the sake of brevity, only one implement and power machine combination is discussed in detail. However, as mentioned above, the embodiments below may be practiced on any of a number of implements and these various implements can be operably coupled to a variety of different power machines.
FIG. 2 is a block diagram illustrating basic systems of power machine 10 as are relevant to interact with implement 18 as well as basic features of implement 18, which represents an implement upon which the embodiments discussed below may be advantageously incorporated. At their most basic level, power machines for the purposes of this discussion include frame 11, power source 12, work element 13, and implement interface 17. On power machines such as loaders and excavators and other similar work vehicles, implement interface 17 includes an implement carrier 20 and a power port 22. The implement carrier 20 may be rotatably attached to a lift arm or another work element and is capable of being secured to the implement. The power port 22 provides a connection for the implement 18 to provide power from the power source to the implement. Power source 12 represents one or more sources of power that are generated on power machine 10. This can include either or both of pressurized fluid and electrical power.
The implement 18, which is sometimes known as an attachment or an attachable implement, has a power machine interface 24 and a tool 26, which is coupled to the power machine interface 24. The power machine interface 24 illustratively includes a machine mount 28 and a power port 30 for coupling with power machine 10. Machine mount 28 can be any structure capable of being coupled to the implement interface 17 of power machine 10. Power port 30, in some embodiments, includes hydraulic and/or electrical couplers. Power port 30 can also include a wireless electrical connection, as may be applicable on a given implement. While both machine mount 28 and power port 30 are shown, some implements may have only one or the other as part of their power machine interface 24.
In FIG. 2, implement 18 illustrates tool 26 as an implement with a work element 32. The tool 26 includes a frame 34, which is coupled with or integral to the machine mount 28. Work element 32 is coupled to frame 34 and is moveable in some way with respect to the frame. An actuator 36 is mounted to frame 34 and to work element 32 and is actuable under power to move the work element with respect to the frame. Power may be provided to the actuator 36 via the power machine, and is selectively provided in the form of pressurized hydraulic fluid (or other power source) directly from the power machine 10 to actuator 36 via power ports 22 and 30.
FIG. 3 is a perspective view of an exemplary landplane implement 100 with exemplary tool, such as a scarifier 126 in a lowered position, according to an embodiment. Landplane implement 100 includes features or tools for performing various landscaping preparation tasks including grading and leveling, peeling sod and scarifying. Landplane implement 100 includes a frame 101 that supports various tools for performing the landscaping preparation tasks. Under one embodiment, frame 101 supports scarifier 126, a pair of cutting edges 104 and grates 106. Scarifier 126 is a tool that includes an elongated rod 108 that extends between right and left side panels of frame 101 and through a center panel of frame 101. Rod 108 is coupled to right and left side panels of frame 101 by bushings. Scarifier 126 further includes a pair of tooth holders. Each tooth holder 110 includes a hollow, cylindrical square bar 111 to which rod 108 is threaded through. A plurality of teeth 112 extend from hollow cylindrical square bar 111 for the task of scarifying. Scarifier 126 is coupled to an actuator, such as hydraulic actuator or cylinder 136, by a protection mechanism trip mechanism 114. Hydraulic actuator 136 is configured to actuate scarifier 126 from a raised position to a lowered position and to actuate scarifier 126 from a lowered position to a raised position. Hydraulic actuator 136 raises and lowers scarifier 126 by rotating bars 111 about rod 108.
FIG. 4 is a perspective view of protection or trip mechanism 114 of landplane implement 100 according to an embodiment, and FIG. 5 is an exploded view of protection mechanism 114. Protection or trip mechanism 114 couples hydraulic actuator 136 to scarifier 126 and includes an upper actuator connector 116, a lower actuator connector 118, first and second trip plates 120 and 122, first and second bar trip interfaces 123 and 124, first and second bar trip mounts 128 and 130, first and second trip springs 132 and 134, a spring bolt 137 and a trip plate stop 138. Upper actuator connector 116 is coupled to lower actuator connector 118. Nestled inside the coupled upper and lower actuator connectors 116 and 118 are first and second trip plates 120 and 122, where trip plate 122 is configured to be rotatable. Located between first and second trip plates 120 and 122 are upper portions of first and second bar trip interfaces 123 and 124. Upper portions of first and second bar trip interfaces 123 and 124 are coupled together by for example, fasteners 125 and 127. However, not only does fastener 125 couple upper portions of first and second bar trip interfaces 123 and 124, but fastener 125 also couples upper portion of first and second bar trip interfaces 123 and 124 to bar trip mount 128 with bar trip mount 128 being mounted to scarifier 126. In addition, not only does fastener 127 couple upper portions of first and second bar trip interfaces 123 and 124, but fastener 127 also couples upper portions of first and second bar trip interfaces 123 and 124 to bar trip mount 130 with bar trip mount 130 being mounted to scarifier 126.
Coupling first and second trip plates 120 and 122 is a spring bolt 137 that also is configured to support first trip spring 132 on one side of the assembly of first and second trip plates 120 and 122 and support second trip spring 124 on an opposing side of the assembly of first and second trip plates 120 and 122. In addition, trip plate stop 138 is coupled to upper actuator connector 116 and extends between first and second trip plates 120 and 122 but is not fixed to first and second trip plates 120 and 122.
FIG. 6 is a section view of landplane implement 100 taken through the section line illustrated in FIG. 3 according to an embodiment. As illustrated in FIG. 6, hydraulic actuator 136 includes a base end that is attached to frame 101 of landplane implement 100 and a rod end that is attached to upper actuator connector 116. When the rod of hydraulic actuator 136 is in a retracted position, scarifier 126 and therefore teeth 112 of scarifier 126 are in a lowered position. In the lowered position, teeth 112 are resting against a hard stop 140 and configured to perform a scarifying operation to the ground. FIG. 7 is a section view of landplane implement 100 but with scarifier 126 in a raised position according to an embodiment. As illustrated in FIG. 7, the base end of hydraulic actuator 136 is attached to frame 101 of landplane implement 100 and the rod end of hydraulic actuator 136 is attached to upper actuator connector 116. When the rod of hydraulic actuator 136 is in an extended position, scarifier 126 and therefore teeth 112 of scarifier 126 are in a raised position.
FIG. 8 is a section view of the landplane implement 100 but with scarifier 126 in a lowered, reversed position according to an embodiment. As illustrated in FIG. 8, depending on the operator's preferred direction of operation, tooth holders 110 that include hollow actuator bars 111 that support teeth 112 of scarifier 126 may be repositioned or reoriented so that landplane implement 100 may be used in an opposing direction from the direction to which landplane implement 100 is used in FIGS. 6 and 7. In one embodiment, to reposition and reorient scarifier 126, hydraulic actuator 136 is decoupled from protection mechanism 114, protection mechanism and scarifier 126 are repositioned and hydraulic actuator 136 is recoupled to protection mechanism 114 with scarifier 126 in this new position. FIG. 8 illustrates this repositioned or reoriented scarifier 126. Like in FIG. 6, when the rod of hydraulic actuator 136 is in a retracted position shown in FIG. 8, scarifier 126 and therefore teeth 112 of scarifier 126 are in a lowered position. In the lowered position, teeth 112 are resting against a hard stop 140 and are configured to perform a scarifying operation to the ground.
Hydraulic actuator 136 is susceptible to damage should one or more teeth of scarifier 126 incur a damaging or high force event that exceeds a threshold torque on the protection mechanism, for example, contacting a large, immovable object or if the operator moves landplane implement 100 in a direction that is opposite to which the teeth are positioned or oriented to properly scarify. Therefore, protection or trip mechanism 114 is configured to protect hydraulic actuator 136 during a potentially damaging event. Protection or trip mechanism 114 provides a spring-loaded mechanism that allows teeth 112 to move from an engaged or lowered position up to a raised or above ground position without affecting the status of hydraulic actuator 136, or in other words, without causing the rod of hydraulic actuator 136 to forcibly extend or forcibly retract.
FIG. 9 is a section view of protection mechanism 114 in a stationary position and taken through the section line illustrated in FIG. 4, and FIG. 10 is a section view of protection mechanism 114 of FIG. 9 but in a tripped position according to an embodiment. In the stationary position illustrated in FIG. 9 and the tripped position illustrated in FIG. 10, hydraulic actuator 136 remains in a constant position, therefore unaffected and protected. In the FIG. 9 stationary position, portions of first and second bar trip interfaces 123 and 124 are sandwiched or located between portions of first and second trip plates 120 and 122. Upon a damaging event or high force event occurring, such as contacting a large object or an operator moving landplane implement 100 in the wrong direction, protection mechanism 114 allows rotation of hollow cylindrical square bar 111 to occur. Such movement of hollow cylindrical square bar 111 (not shown in FIGS. 9 and 10, but would be located between bar trip mount 128 and bar trip interface 123) will cause first and second bar trip interfaces 123 and 124 and second rotatable trip plate 122 to rotate away from and relative to stationary first trip plate 120. This causes spring bolt 137 that extends through first trip plate 120 and second trip plate 122 to rotate to compress first and second trip springs 132 and 134 in the same direction as first and second bar trip interfaces 123 and 124 and second trip plate 122. As illustrated in FIGS. 6-8, protection or trip mechanism 114 may work in either operational direction of landplane implement 100.
FIG. 11 is a perspective view of a landplane implement 200 with a scarifier 226 in a lowered position according to another embodiment. Landplane implement 200 includes features or tools for performing various landscaping preparation tasks including grading and leveling, peeling sod and scarifying. Landplane implement 200 includes a frame 201 that supports various tools for performing the landscaping preparation tasks. Under one embodiment, frame 201 supports scarifier 226, a pair of cutting edges 204 and grates 206. Scarifier 226 is a tool that includes an elongated rod 208 that extends between right and left side panels of frame 201 and through a center panel of frame 201. Rod 208 is coupled to right and left side panels of frame 201 by bushings. Scarifier 226 further includes a pair of tooth holders 210. Each tooth holder 210 includes a hollow cylindrical square bar 211 to which rod 208 is threaded through and are rotatable. A plurality of teeth 212 extend from hollow cylindrical square bar 211 for the task of scarifying. Scarifier 226 is coupled to an actuator, such as hydraulic actuator 236. Hydraulic actuator 236 is configured to actuate scarifier 226 from a raised position to a lowered position and to actuate scarifier 226 from a lowered position to a raised position. Hydraulic actuator 236 raises and lowers scarifier 226 by rotating bars 211 about rod 208. Rather than landplane implement having a trip mechanism as described above, hydraulic actuator 236 and the hydraulic circuitry to which it is coupled to includes its own protection mechanism.
FIG. 12 is a section view of landplane implement 200 taken through the section line illustrated in FIG. 11 according to an embodiment. As illustrated in FIG. 12, hydraulic actuator 236 includes a base end 242 that is attached to frame 201 of landplane implement 200 and a rod end 244 that is attached to an actuator connector 216. When the rod of hydraulic actuator 236 is in a retracted position as illustrated in FIG. 12, scarifier 226 and therefore teeth 212 of scarifier 226 are in a lowered position. In the lowered position, teeth 212 are resting against a hard stop 240 and configured to perform a scarifying operation to the ground. FIG. 13 is a section view of landplane implement 200 but with scarifier 226 in a raised position according to an embodiment. As illustrated in FIG. 13, base end 242 of hydraulic actuator 236 is attached to frame 201 of landplane implement 200 and the rod end 244 of hydraulic actuator 236 is attached to actuator connector 216. When the rod of hydraulic actuator 236 is in an extended position, scarifier 226 and therefore teeth 212 of scarifier 226 are in a raised position.
FIG. 14 is a section view of the landplane implement 200 but with scarifier 226 in a lowered, reversed position according to an embodiment. As illustrated in FIG. 14, depending on the operator's preferred direction of operation, tooth holders 210 that include hollow actuator bars 211 that support teeth 212 of scarifier 226 may be repositioned or reoriented so that landplane implement 200 may be used in an opposing direction from the direction to which landplane implement 200 is used in FIGS. 12 and 13. In one embodiment, to reposition and reorient scarifier 226, hydraulic actuator 236 is decoupled from actuator connector 216, scarifier 226 is repositioned and hydraulic actuator 236 is recoupled to actuator connector 216. FIG. 14 illustrates this repositioned or reoriented scarifier 226. Like in FIG. 12, when the rod of hydraulic actuator 236 is in a retracted position shown in FIG. 14, scarifier 226 and therefore teeth 212 of scarifier 226 are in a lowered position. In the lowered position, teeth 212 are resting against a hard stop 240 and are configured to perform a scarifying operation to the ground.
FIG. 15 is a section view of landplane implement 200 but with scarifier 226 in a raised, reversed position according to an embodiment. As illustrated in FIG. 15, base end 242 of hydraulic actuator 236 is attached to frame 201 of landplane implement 200 and the rod end 244 of hydraulic actuator 236 is attached to actuator connector 216. When the rod of hydraulic actuator 236 is in an extended position, scarifier 226 and therefore teeth 212 of scarifier 226 are in a raised position.
Hydraulic actuator 236 is susceptible to damage should one or more teeth of scarifier 226 incur a damaging or high force event, for example, contacting a large object or if the operator moves landplane implement 200 in a direction that is opposite to which the teeth are positioned or oriented to properly scarify. Therefore, an hydraulic circuit configuration acts as a protection mechanism to protect hydraulic actuator 236 during a potentially damaging or high force event.
FIG. 16 is a schematic diagram of one embodiment of a hydraulic circuit 250 including a protection mechanism 251 and illustrating hydraulic actuator 236 actuating the scarifier in a raised position. FIG. 17 is a schematic diagram of one embodiment of hydraulic circuit 250 including protection mechanism 251 and illustrating hydraulic actuator 236 actuating the scarifier in a lowered position. As illustrated in FIG. 16 and during normal operation of raising scarifier 226, a first auxiliary coupler 240, such as a male auxiliary coupler, is configured to be coupled to a source of hydraulic fluid on a power machine. Hydraulic fluid from first coupler 240 pressurizes hydraulic circuit 250 and therefore a base end 242 of hydraulic actuator 236 to extend a rod of hydraulic actuator 236 (as indicated by arrow 245). During the pressurization of base end 242, low pressure hydraulic fluid is forced out of rod end 244 to a second auxiliary coupler 241, such as a female auxiliary coupler, that is configured to be coupled to the source of hydraulic fluid on the power machine.
In addition, hydraulic circuit 250 includes an orifice 246 that is in line with high pressure hydraulic fluid that builds up back pressure during pressurization. In time, the buildup of back pressure induces the functioning of protection mechanism 251. Protection mechanism 251 includes first, second, third and fourth check valves 248, 254, 256 and 258 and an accumulator 252. In particular, the buildup of back pressure breaks first check valve 248 and is allowed to build up pressure in accumulator 252. For example, first check valve 248 may be set at 5 psi. Therefore, when the back pressure exceeds 5 psi, first check valve 248 is broken and a certain amount of hydraulic fluid volume is allowed to fill accumulator 252. After accumulator 252 receives a threshold storage amount, hydraulic fluid breaks through second check valve 254 and moves to second coupler 241. For example, second check valve 254 may be set at 225 psi. Therefore, when pressure exceeds 225 psi, second check valve 254 is broken and hydraulic fluid moves to second coupler 241.
As illustrated in FIG. 17 and during normal operation of lowering scarifier 226, hydraulic fluid from second coupler 241 pressurizes hydraulic circuit 250 and therefore rod end 244 of hydraulic actuator 236 to retract the rod of hydraulic actuator 235 (as indicated by arrow 247). During the pressurization of rod end 244, low pressure hydraulic fluid is forced out of base end 242 to first coupler 240. In addition, and as previously discussed, hydraulic circuit 250 builds up back pressure during pressurization. In time, the back flow of pressure breaks third check valve 256 and is allowed to build up pressure in accumulator 252. For example, third check valve 256 may be set at 5 psi. Therefore, when the back pressure exceeds 5 psi, third check valve 256 is broken and a certain amount of hydraulic fluid volume is allowed to fill accumulator 252. After accumulator 252 meets a threshold of storage, hydraulic fluid breaks through a fourth check valve 258 and moves to first coupler 240. For example, fourth check valve 258 may be set at 225 psi. Therefore, when pressure exceeds 225 psi, fourth check valve 258 is broken and hydraulic fluid moves to first coupler 240. As described, normal functioning of hydraulic circuit 250 occurs when an operator commands flow to rod end 242 or base end 244 so that hydraulic actuator 236 is moved as intended, and during that time, hydraulic fluid is also diverted to accumulator 252 and filled so that a volume of hydraulic fluid is available to prevent damage to actuator 236 under unintended loadings.
FIG. 18 is a schematic diagram of one embodiment of hydraulic circuit 250 including protection mechanism 251 and illustrating an occurrence of an external force event that causes a forced extension of hydraulic actuator 236 and therefore forced raising of scarifier 226 under one embodiment. FIG. 19 is a schematic diagram of one embodiment hydraulic circuit 250 including protection mechanism 251 and illustrating an occurrence of an external force event that causes forced retraction of hydraulic actuator 236 and therefore forced lowering of scarifier 226 under one embodiment. As illustrated in FIG. 18, when an external, unintended tension force causes a forced extension of the rod of hydraulic actuator 236 or forced raising of scarifier 226, pre-filled or pre-charged hydraulic fluid is pulled from accumulator 252 that was previously charged during normal actuator operation. This is accomplished by accounting for the differential volume of hydraulic fluid between rod end 244 and base end 242. In this case, a forced extension or force raising of scarifier 226 causes hydraulic fluid to flow from rod end 244 through third check valve 256 and from accumulator 252 through fourth check valve 258 to fill base end 242 as illustrated by the direction arrows of flow in FIG. 18. For example, when scarifier 226 is lowered and an operator attempts to drive opposite of the normal scarifying direction such an external force can cause unintended forcible extension of the rod and therefore raising of scarifier 226.
As illustrated in FIG. 19, when external, an unintended compression force causes a forced retraction of the rod or forced lowering of scarifier 226, the differential volume of hydraulic fluid between the rod and base ends 244 and 242 is accounted for by filling accumulator 252 with the excess hydraulic fluid. In this case, a forced retraction or forced lowering of scarifier 226 requires hydraulic fluid to flow from base end 242 through first check valve 248 to accumulator 252 and through second check valve 254 to rod end 244 as illustrated by the direction arrows of flow in FIG. 19. In contrast to FIG. 18, additional hydraulic fluid in FIG. 19 is going into accumulator 252 rather than out. After this unintended event, the operator may reduce the flow back to 225 psi and allow hydraulic fluid to escape from accumulator 252 back to a normal level. For example, when the scarifier 226 is not fully lowered and the operator attempts to scarify with scarifier 226 only partially engaged may cause unintended retraction of the rod therefore lowering of scarifier 226. In both FIGS. 18 and 19, protection mechanism 251 provides hydraulic protection to hydraulic actuator 236, frame 201 and scarifier 226.
In some circumstances, it is possible that when the operator is either lowering scarifier 226 or raising scarifier 226, the scarifier comes across an object that moves against the intended motion, or in other words, an immovable object. In this case, pressure in hydraulic circuit 250 exceeds the check valves. FIG. 20 is a schematic diagram of one embodiment of hydraulic circuit 250 including protection mechanism 251 and illustrating scarifier 226 contacting an immovable object when the scarifier is in the raised position under one embodiment. FIG. 21 is a schematic diagram of one embodiment of hydraulic circuit 250 including protection mechanism 251 and illustrating scarifier 226 contacting an immovable object when the scarifier is in the lowered position. In either the configuration illustrated in FIG. 20 or FIG. 21, hydraulic fluid flow is directed back to the power machine rather than causing high pressure. As illustrated in FIG. 20, when scarifier 226 comes up against an immovable object while raising scarifier 226, pressurized flow entering from first coupler 240 builds up against the immovable object causing flow to go through first check valve 248, fill accumulator 252 to the extent that accumulator 252 is not already fully charged, proceed through second check valve 254 and through second coupler 241 back to the power machine. As illustrated in FIG. 21, when scarifier 226 comes up against an immovable object while lowering scarifier 226, pressurized flow entering from second coupler 241 builds up against the immovable object causing flow to go through third check valve 256, fill accumulator 252 to the extent that accumulator 252 is not already fully charged, proceed through fourth check valve 258 and through first coupler 240 back to the power machine.
FIG. 22 is a schematic diagram of another embodiment of a hydraulic circuit 350 including a protection mechanism 351 and illustrating hydraulic actuator 236 actuating the scarifier in a raised position. FIG. 23 is a schematic diagram of one embodiment of hydraulic circuit 350 including protection mechanism 351 and illustrating hydraulic actuator 236 actuating the scarifier in a lowered position. As illustrated in FIG. 22 and during the normal operation of raising scarifier 226, a first auxiliary coupler 340, such as a male auxiliary coupler, is configured to be coupled to a source of hydraulic fluid on a power machine. Hydraulic fluid from first coupler 340 pressurizes hydraulic circuit 350, which includes a meter-in orifice 360. Meter-in orifice 360 includes an orifice and check valve. The check valve of 360 prevents flow from going back in the direction of first coupler 340, while the orifice of 360 allows a low flowrate to pressurize base end 242 of hydraulic actuator 236 to extend the rod of hydraulic actuator 236 (as indicated by arrow 245) and force low pressure hydraulic fluid out of rod end 244 to a second auxiliary coupler 341, such as a female auxiliary coupler, that is configured to be coupled to the source of hydraulic fluid on the power machine. An excess of low flowrate hydraulic fluid from meter-in orifice 360 travels to protection mechanism 351. Protection mechanism 351 includes first, second, third and fourth check valves 362, 366, 370 and 372 and a case drain line 365 and having an actuator relief valve 363. In particular, excess of low flowrate hydraulic fluid travels through first check valve 362. Actuator relief valve 363 may be set above normal operating conditions, such as 250 psi. This means that actuator relief valve 363 prevents case drain line 365 from being used and that hydraulic fluid will move to second coupler 341. However, it is possible that at an end of stroke, the pressure may exceed normal operating conditions and some hydraulic fluid may flow through actuator relief valve 363 to case drain line 365 of protection mechanism 351 that has a third auxiliary coupler 368 and therefore to the power machine.
As illustrated in FIG. 23 and during the normal operation of lowering scarifier 226, hydraulic fluid from second coupler 341 pressurizes hydraulic circuit 350, which includes a meter-in orifice 364. Meter-in orifice 364 includes an orifice and check valve. The check valve of 364 prevents flow from going back in the direction of second coupler 341, while the orifice of 364 allows a low flowrate to pressurize actuator end 244 of hydraulic actuator 236 to retract hydraulic actuator 236 (as indicated by arrow 247) and force low pressure hydraulic fluid out of base end 242 to first coupler 340. An excess of low flow rate hydraulic fluid from meter-in orifice 364 travels to protection mechanism 352. In particular, excess of low flowrate hydraulic fluid travels through second check valve 366. Actuator relief valve 363 may be set above normal operating conditions, such as 250 psi. This means that actuator relief valve 363 prevents case drain line 365 from being used and that hydraulic fluid will move to first coupler 340. However, it is possible that at an end of stroke, the pressure may exceed normal operating conditions and some hydraulic fluid may flow through actuator relief valve 363 to case drain line 365 of protection mechanism 351 and to third coupler 368 and therefore to the power machine. As described and in general, normal functioning of hydraulic circuit 350 occurs when an operator commands flow to base end 242 or rod end 244 so that hydraulic actuator 236 is moved as intended, and during that time, excess flow is diverted to second coupler 341 or first coupler 240.
FIG. 24 is a schematic diagram of one embodiment of hydraulic circuit 350 including the protection mechanism 351 and illustrating an occurrence of an unintended external force event that causes a forced extension of hydraulic actuator 236 and therefore the forced raising of scarifier 226. FIG. 25 is a schematic diagram of one embodiment of hydraulic circuit 350 including protection mechanism 351 and illustrating an occurrence of an unintended external force event that causes forced retraction of hydraulic actuator 236 and therefore force lowering of scarifier 226. As illustrated in FIG. 24, when an external, unintended tension force causes a forced extension of the rod or forced raising of scarifier 226, a vacuum condition occurs and the volume differential of hydraulic fluid is taken from third coupler 368 through case drain line 365 from the power machine. In this case, a forced extension or forced raising of scarifier 226 causes hydraulic fluid to flow from rod end 244 through second check valve 366 and actuator relief valve 363 and combine with flow from case drain line 365. The combined hydraulic fluid flows through third check valve 370 to fill base end 242 as illustrated by the direction arrows. For example, when scarifier 226 is lowered and an operator attempts to drive opposite of the normal scarifying direction such an external force can cause unintended extension of the rod and therefore raising of scarifier 226.
As illustrated in FIG. 25, when external, an unintended compression forces causes a forced retraction of the rod or forced lowering of scarifier 226, the differential volume of hydraulic fluid between the rod and base ends 244 and 242 is accounted for by filling the power machine with the excess hydraulic fluid using case drain line 365 and third coupler 368. In this case, a forced retraction or forced lowering of scarifier 226 requires hydraulic to flow from base end 242 through first check valve 362 and actuator relief valve 363. At this point, some of the hydraulic fluid proceeds through a fourth check valve 372 and excess hydraulic fluid is metered out through optional meter-out case drain orifice check valve 374 in case drain line 365 to third coupler 368 and the power machine. The hydraulic fluid that flows through fourth check valve 372 flows to rod end 244 as illustrated by the direction arrows in FIG. 25. In contrast to FIG. 24, additional hydraulic fluid in FIG. 25 is going to the power machine through case drain line 365 rather than being pulled out. After this unintended event, the operator may reduce the flow back to 225 psi and allow hydraulic fluid to go back to a normal level. For example, when the scarifier 226 is not fully lowered and the operator attempts to scarify with scarifier 226 only partially engaged may cause unintended retraction of the rod therefore lowering of scarifier 226. In both FIGS. 20 and 21, protection mechanism 351 provides hydraulic protection to hydraulic actuator 236, frame 201 and scarifier 226.
In some circumstances, it is possible that when the operator is either lowering scarifier 226 or raising scarifier 226, the scarifier comes across an object that moves against the intended motion. In this case, hydraulic circuit 350 exceeds the normal operating pressures. FIG. 26 is a schematic diagram of hydraulic circuit 350 including protection mechanism 351 and illustrating scarifier 226 contacting an immovable object in the raised position under one embodiment. FIG. 27 is a schematic diagram of hydraulic circuit 350 including protection mechanism 351 and illustrating scarifier 226 contacting an immovable object when in the lowered position under one embodiment.
In either the configuration illustrated in FIG. 26 or FIG. 27, hydraulic fluid flow is directed back to the power machine rather than causing high pressure. As illustrated in FIG. 26, when scarifier 226 comes up against an immovable object while raising scarifier 226, pressurized flow entering from first coupler 340 and through meter-in orifice check valve 360 builds up against the immovable object causing flow to go through first check valve 362, through actuator relief valve 363 and fills the power machine through case drain line 365 and third coupler 368 and also second coupler 341 by flowing through fourth check valve 372. The majority of the flow amount enters the power machine through second coupler 341 and a smaller amount through optional meter-out case drain orifice and check valve 374 in case drain line 365 and to case drain coupler 368. As illustrated in FIG. 27, when scarifier 226 comes up against an immovable object while lowering scarifier 226, pressurized flow entering from second coupler 241 and through meter-in orifice check valve 364 builds up against the immovable object causing flow to go through second check valve 366, through actuator relief valve 363 and fills the power machine through case drain line 365 and third coupler 368 and also first coupler 340 by flowing through third check valve 370. The majority of the flow amount enters the power machine through first coupler 340 and a smaller amount through optional meter-out case drain orifice and check valve 374 in case drain line 365 and to third coupler 368.
FIG. 28 is a schematic diagram of another embodiment of a hydraulic circuit 450 including a protection mechanism 451 and illustrating hydraulic actuator 236 actuating scarifier 226 in a raised position. FIG. 29 is a schematic diagram of one embodiment of hydraulic circuit 450 including protection mechanism 451 and illustrating hydraulic actuator 236 actuating scarifier 226 in a lowered position. As illustrated in FIG. 28 and during the normal operation of raising scarifier 226, a first auxiliary coupler 440, such as a male auxiliary coupler, is configured to be coupled to a source of hydraulic fluid on a power machine. Hydraulic fluid from first coupler 440 pressurizes hydraulic circuit 450, which includes a meter-in orifice and check valve 460. The check valve of 460 prevents flow from going back in the direction of first coupler 440, while the orifice of 460 allows a low flowrate to pressurize base end 242 of hydraulic actuator 236 to extend the rod of hydraulic actuator 236 (as indicated by arrow 245) and force low pressure hydraulic fluid out of rod end 244 to a second auxiliary coupler 441, such as a female auxiliary coupler that is configured to be coupled to the source of hydraulic fluid on the power machine. An excess of low flow rate hydraulic fluid from meter-in orifice and check valve 460 may divert to protection mechanism 451. Protection mechanism 451 includes first, second, third and fourth check valves 462, 466, 470 and 472 and a case drain line 465 having an optional meter-out case drain orifice check valve 474. In particular, excess of low flowrate hydraulic fluid diverts to first check valve 462, but does not travel through first check valve 462 unless a threshold of pressure is reached, such as 300 psi. This means that first check valve 462 prevents case drain line 465 from being used. However, it is possible that an end of stroke, the pressure may exceed normal operating conditions and some hydraulic fluid may flow through check valve 462 to case drain line 465 of protection mechanism 451 that has third auxiliary coupler 468 and therefore to the power machine.
As illustrated in FIG. 29 and during the normal operation of lowering scarifier 226, hydraulic fluid from second coupler 441 pressurizes hydraulic circuit 450, which includes a meter-in orifice and check valve 464. The check valve of 464 prevents flow from going back in the direction of second coupler 441, while the orifice of 464 allows a low flowrate to pressurize rod end 244 of hydraulic actuator 236 to retract the hydraulic actuator (as indicated by arrow 247) and force low pressure hydraulic fluid out of base end 242 to first coupler 440. An excess of low flow rate may divert, but does not travel through second check valve 466 of protection mechanism 451 until a threshold of pressure is reached, such as 300 psi. This means second check valve 466 prevents case drain line 465 from being used. However, it is possible that an end of stroke, the pressure may exceed normal operating conditions and some hydraulic fluid may flow through second check valve 466 to case drain line 465 of protection mechanism 451 and to third coupler 368 and therefore to the power machine. As described and in general, normal functioning of hydraulic circuit 450 occurs when an operator commands flow to base end 242 or rod end 244 so that hydraulic actuator 236 is moved as intended, and during that time, excess flow is diverted to second coupler 441 or first coupler 440.
FIG. 30 is a schematic diagram of hydraulic circuit 450 including protection mechanism 451 and illustrating an occurrence of an unintended external force event that causes forced extension of hydraulic actuator 236 and therefore the forced raising of scarifier 226 under one embodiment. FIG. 31 is a schematic diagram of the hydraulic circuit including the protection mechanism in FIG. 28 and illustrating an occurrence of an unintended external force event that causes forced retraction of the hydraulic actuator and therefore the forced lowering of scarifier 226 under one embodiment. As illustrated in FIG. 30, when external, unintended tension forces cause a forced extension of the rod or forced raising of scarifier 226, a vacuum condition occurs and the volume differential of hydraulic fluid is taken from third coupler 468 through case drain line 465 from the power machine. In this case, a forced extension or forced raising of scarifier 226 causes hydraulic fluid to flow from rod end 244 through second check valve 466 and combine with flow from case drain line 465. The combined hydraulic fluid flows through third check valve 470 to fill base end 242 as illustrated by the direction arrows. For example, when scarifier 226 is lowered and an operator attempts to drive opposite of the normal scarifying direction such an external force can cause unintended extension of the rod and therefore raising of scarifier 226.
As illustrated in FIG. 31, when external, unintended compression forces cause a forced retraction of the rod or forced lowering of scarifier 226, the differential volume of hydraulic fluid between the rod and base ends 244 and 242 is accounted for by filling the power machine with the excess hydraulic fluid using case drain line 465 and third coupler 468. In this case, a forced retraction or forced lowering of scarifier 226 causes hydraulic fluid to flow from base end 242 through first check valve 462. Some of the hydraulic fluid proceeds through a fourth check valve 472 and excess hydraulic fluid goes to case drain line 465 and is metered out through optional meter-out case drain orifice check valve 474 into third coupler 468 and the power machine. The hydraulic fluid that flows through fourth check valve 472 flows to rod end 244 as illustrated by the direction arrows in FIG. 31. In contrast to FIG. 30, additional hydraulic fluid in FIG. 31 is going to the power machine through case drain line 465 rather than being pulled out. For example, when the scarifier 226 is not fully lowered and the operator attempts to scarify with scarifier 226 only partially engaged may cause unintended retraction of the rod therefore lowering of scarifier 226. In both FIGS. 30 and 31, protection mechanism 451 provides hydraulic protection to hydraulic actuator 236, frame 201 and scarifier 226.
In some circumstances, it is possible that when the operator is either lowering scarifier 226 or raising scarifier 226, the scarifier comes across an object that moves against the intended motion. In this case, hydraulic circuit 450 exceeds the normal operating pressures. FIG. 32 is a schematic diagram of hydraulic circuit 450 including protection mechanism 451 in FIG. 28 and illustrating scarifier 226 contacting an immovable object when in the raised position under one embodiment. FIG. 33 is a schematic diagram of hydraulic circuit 450 including protection mechanism 451 in FIG. 28 and illustrating scarifier 226 contacting an immovable object when in the lowered position under one embodiment.
In either the configuration illustrated in FIG. 32 or FIG. 33, hydraulic fluid flow is directed back to the power machine rather than causing high pressure. As illustrated in FIG. 32, when scarifier 226 comes up against an immovable object while raising scarifier 226, pressurized flow entering from first coupler 440 and through meter-in orifice check valve 460 builds up against the immovable object causing flow to go through first check valve 462 and fill the power machine through case drain line 465 and second coupler 441 by flowing through fourth check valve 472. The majority of the flow amount enters the power machine through second coupler 441 and a smaller amount through case drain line 465, optional meter-out case drain orifice and check valve 474 and to third coupler 468. As illustrated in FIG. 33, when scarifier 226 comes up against an immovable object while lowering scarifier 226, pressurized flow entering from second coupler 441 and through meter-in orifice check valve 464 builds up against the immovable object causing flow to go through second check valve 466 and fill the power machine through case drain line 465 and first coupler 440 by flowing through third check valve 470. The majority of the flow amount enters the power machine through first coupler 440 and a smaller amount through case drain line 465, optional meter-out case drain orifice and check valve 474 and to third coupler 468.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
Patent Application
20250059732
