FIELD
The present discussion relates to a work implement for a power machine such as an excavator. In particular, the present discussion relates to pallet fork implements or attachments which can be mounted or engaged on a blade of a power machine and which can be stowed in a carrier system attached to or proximate an undercarriage of the power machine.
BACKGROUND
Forklifts are commonly used to lift pallets and other loads. Forklifts include pallet forks that engage a pallet or other load to be lifted, allowing a lift mechanism of the fork lift to lift the load in a stabilized manner. It is frequently too costly and otherwise inconvenient to have a forklift available at a worksite, particularly since the need for the forklift may be temporary, short term, and/or otherwise infrequent.
To reduce the need for a separate forklift vehicle at a worksite, pallet forks have been fixedly attached to other implements or attachments of power machines. For example, pallet forks have been attached to buckets for this purpose. To accomplish the attachment of pallet forks to a bucket or other type of attachments, some sort of mounting structure on the host attachment is used to engage with the pallet forks to fixedly attach the forks to the host attachment. This type of mounting structure adds cost and complexity to the power machine, to the host attachment, and/or to the pallet fork implement.
In at least some instances, pallet fork assemblies that are designed to engage attachments of a power machine have required adjustability to work with a variety of host attachments. They have also required fastening mechanisms that are used to secure the pallet fork assemblies to the implement. The need for adjustable pallet fork implements and/or the need for the pallet fork implements to include fastening mechanisms can increase manufacturing costs, manufacturing complexity, installation time, etc.
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
A pallet fork implement is configured to be mounted on a blade of a power machine. The pallet fork attachment includes an engagement portion for engaging the blade of the power machine, and a tine portion for performing a work function. The tine portion is configured to extend generally forward of the blade when the engagement portion is engaged with the blade. The engagement portion of the pallet fork implement is a unitary assembly.
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. This Summary and the Abstract are not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a power machine having a host blade attachment or implement that receives a pallet fork implement in accordance with disclosed embodiments.
FIG. 1A is a perspective view of the power machine of FIG. 1, with pallet fork implements mounted on the host blade attachment.
FIG. 2 is a perspective view of portions of an undercarriage of a power machine, such as the one shown in FIG. 1, illustrating pallet fork implements in both mounted and stowed positions.
FIGS. 3A and 3B illustrate top and side views of an embodiment of the pallet fork implement.
FIG. 4 is a rear view illustration of a portion of the power machine of FIG. 1, with a pair of pallet fork implements in a stowed position.
FIG. 5 is a diagrammatic side view of the pallet fork implement in position to be accepted onto a host blade attachment shown in cross section, illustrating features of the pallet fork attachment that aid in installation and use.
FIG. 6 is a diagrammatic side view of the pallet fork attachment accepted onto a host blade attachment shown in cross-section, illustrating features of the pallet fork attachment that aid in installation and use.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
FIG. 1 illustrates a perspective view of a power machine 100. For illustrative purposes, power machine 100 is shown to be a self-propelled power excavator that has a chassis or undercarriage 102 and an upper rotatable frame 104. However, power machine 100 need not be an excavator, but can instead be other types of power machine. Undercarriage 102 includes a lower frame 106 and a pair of support surface engaging track assemblies 108 that are attached to the lower frame 106 and driven with a suitable drive arrangement, such as with hydraulic drive motors. Upper rotatable frame 104 supports a pivotally mounted two-section boom-arm structure 110, which illustratively includes both a boom section 111 and an arm section 113, capable of having an implement 112 (a bucket is shown in FIG. 1) attached to an outer end thereof. The sections of boom-arm structure 110 are illustratively operated with actuators shown generally at 114 for moving the boom and arm sections about horizontal pivots. Implement 112 is also operated with an actuator 116 to allow for pivotable movement of the implement 112 with respect to the arm section 113. Upper rotatable frame 104 also includes an operator compartment 118 and a housing 120 for an engine for providing power to the suitable drive arrangement that drives the pair of ground engaging track assemblies 108. A plurality of actuation devices (not shown in FIG. 1) are positioned within the operator compartment 118 to allow an operator to control functions of the machine including, for example, the drive function and manipulation of the boom-arm structure 110 and the implement 112. Although this and other power machines illustrated in this discussion are power machines with operator compartments capable of carrying an operator, it should be appreciated that the embodiments discussed herein can be incorporated into various other power machines, including walk behind machines.
The power machine 100 illustrated in FIG. 1 also includes an implement assembly 122, which is operably coupled to the lower frame 106. The implement assembly 122 illustratively includes a pair of lift arms 124 that are rotatably coupled to the lower frame 106 at pivot points 126. A pair of actuators 128 is also coupled to the lower frame 106 and lift arms 124. A blade 130 is illustratively coupled to the lift arms 124. In one embodiment, the blade 130 is fixedly attached to each of the lift arms 124. Other arrangements are contemplated. For example, the blade 130 can alternatively be attached to an attachment mechanism such as a cross member (not shown) that is in turn attached to the lift arms. Alternatively still, the blade 130 can be pivotally attached to the lift arms 124. The actuators 128 are capable of rotating the lift arms 124 with respect to the lower frame 106 to raise and lower the blade 130. While FIG. 1 shows two actuators 128, alternatively, a single actuator may be employed to control the angular position of the lift arms 124 with respect to the lower frame 106.
FIG. 1A illustrates power machine 100, with a pair of pallet forks 230 engaged with the blade 130 so that the pallet forks 230 hang from the blade 130 when mounted thereto. For the purposes of this discussion, the blade 130 is a host implement or implement carrier that is capable of receiving one or more pallet forks 230. The pallet forks 230 are an illustrative example of an implement that can be attached to or engaged with the host implement, in this illustration, blade 130. Other implements besides forks or pallet forks capable of being engaged with a host implement are contemplated. While the forks 230 are described as pallet forks with reference to this and other figures, it should be appreciated that forks 230 can engage and support other structures besides pallets and the use of the term pallet fork should in no way be construed to limit the interpretation of forks 230 to that of being able to engage only pallets.
FIG. 2 illustrates an undercarriage 200 similar to the undercarriage 102 illustrated in FIG. 1. Undercarriage 200 is configured to accept and be operably coupled to an upper rotatable frame of the type illustrated in FIG. 1. The undercarriage 200 includes a frame 202 to which a pair of support surface engaging track assemblies 204 are coupled. A pair of lift arms 206 (e.g., corresponding to lift arms 124 in FIGS. 1 and 1A) are rotatably coupled to the frame 202 at pivot points 208 and extend from the frame 202 on one side thereof. A cross member 210 is positioned between and attached to each of the lift arms 206. A bracket 212 extends from the cross member 210 and is configured to accept and be secured to an actuator (not shown in FIG. 2) of the type that is capable of controlling the rotational position of the lift arms 206. Frame 202 also has a bracket 214, which is likewise capable of accepting and being secured to the actuator. A blade 216 (e.g., corresponding to blade 130 shown in FIGS. 1 and 1A) is illustratively coupled to each of the lift arms 206. The blade 216 includes a generally rectangular moldboard 218, having opposing ends 222 and 224, which is capable of engaging and pushing material. The distance W between the opposing ends 222 and 224 is considered to be the width of the blade 216. The blade 216 also includes a lip 220, which extends away from the top of the moldboard 218 and generally toward the frame 202 along all or substantially all of the width W of the blade 216. A cutting edge 226 extends along a bottom of the moldboard 218 along all or substantially all of the width W of the blade 216. The cutting edge 226 is illustratively an edge of the moldboard 218. Alternatively, the cutting edge is a piece of material that is fastened, removably or otherwise, to the moldboard 218. Like FIG. 1A, a pair of pallet forks 230 is shown engaged with the blade 216, although it is to be understood one or more than two pallet forks 230 can be engaged with blade 216 as may be advantageous to perform a particular function. References herein to engagement of pallet forks 230 with blade 218 should be interpreted as engaging in the same manner with similar blade embodiments, such as blade 130 shown in FIGS. 1 and 1A.
FIGS. 3A and 3B illustrate the pallet forks 230. For the purposes of this discussion, the pallet forks 230 in particular and implements of the type that can engage a host implement in general illustratively include an engagement portion and a work portion. The pallet forks 230 include an engagement or mounting portion 232 and a work portion in the form of a tine 234, which extends from the mounting portion 232 at a departure angle 236. Departure angle 236 is generally an obtuse angle, but any advantageous departure angle can be employed. The tine 234 has a length L that is advantageous for engaging pallets or other objects that may be carried on one or more pallet forks 230 when they are engaged with blade 216. The tine 234 has a tapered end 235, which allows the tine to more easily engage objects that it is employed to lift. The tines 234 of pallet forks 230 shown in FIGS. 3A and 3B are illustrative in nature and any acceptable shape, length, thickness, or width may be employed without departing from the scope of the discussion.
The mounting portion 232 includes an engagement structure 248 for engaging the blade 216 illustrated in FIG. 2. The engagement structure includes a lip engagement member 238. The lip engagement member 238 is shaped to allow the pallet fork to engage the lip 220 of blade 216. A face 240 extends between the lip 220 and the cutting edge 226 of the blade when the pallet fork 230 is coupled to the blade 216. It is not necessary, however, for the face 240 to conform to the shape of the moldboard 216. The engagement structure 248 also includes a protrusion 242, which is configured to engage the cutting edge 226 by resting against the cutting edge to provide some support between the pallet fork 230 and the blade 216.
Because the blade 216 has a lip 220 and a cutting edge 226 that extend from one side 222 to the other side 224 and have, in one embodiment, a similar cross sectional profile over all or part of the width W of the blade 216, the pallet forks 230 can advantageously be positioned along any location of the width W (or alternatively along substantial portions of the width W) of the blade 216, which provides flexibility in terms of what the pallet forks can engage. While FIG. 2 shows two pallet forks, it should be appreciated that any number of pallet forks can be attached to the blade 216, which can be advantageous when engaging some objects.
The pallet forks 230 are mounted onto the blade 216 by positioning the pallet fork 230 so that it extends forward from the blade 216 and rotating the pallet fork 230 so that the lip engagement member 238 is capable of engaging the lip 220. Then, the fork is pulled forward and rotated down until the protrusion 242 engages and rests against the cutting edge 226. In some embodiments, the engagement portion is a rigid, unitary assembly when manufactured, although it may be assembled from a plurality of components such as by welding metal parts together. It should be appreciated that by unitary assembly, it is meant that the assembly is not capable of disassembly, adjustment, and does not include a portion that is pivotable with respect to another portion of the assembly. That is, the engagement portion is manufactured so that the unitary assembly is configured to engage and be accepted by the implement carrier. Furthermore, the engagement and work portions are, in some embodiments, a unitary assembly when manufactured.
Returning to FIG. 2, undercarriage 200 provides a structure for storage of pallet forks 230 when they are not in use. Two pallet forks 230A are shown (in dashed lines) secured to the undercarriage 200. Two pairs of brackets 244 are mounted to the frame 202. The pairs of brackets 244 on each side of the frame 202 are aligned so that the tines of pallet forks 230A are accepted into each of the brackets. The pallet forks 230A are illustratively inserted into the brackets 244 from a side of the frame 202 that is opposite to the side of the frame that supports the lift arms 206. Once inserted into the brackets 244, the pallet forks 230A are illustratively secured to the frame 202. FIG. 4 illustrates a pair of pallet forks 230A that are positioned within the frame of a work machine 300. An attachment device 252 (in this figure a chain) is used to secure the pallet forks to each other and to a mounting structure 250, which extends from frame 202, or directly to the frame. Although two sets of pallet forks are shown in FIG. 2 (mounted pallet forks 230 and stored pallet forks 230A shown in dashed lines), this is shown for illustrative purposes to demonstrate various features. One skilled in the art will recognize that only one pair of pallet forks will generally be included, and those pallet forks can be moved between the mounted and stored positions.
FIGS. 5 and 6 illustrate a cross section of a blade assembly 600 and a portion of pallet fork 602. In FIG. 5, the pallet fork 602 is shown in position to be engaged with the blade assembly 600 and in FIG. 6, the pallet fork 602 is shown in an engaged position with respect to the blade assembly 600. The blade assembly 600 includes a cross section of a lift arm 604 and an attachment structure 606, which couples the lift arm 604 to a blade 608. An end plate 610 is attached to one end of the blade 608. The blade 608 includes a moldboard 636, with a cutting edge 612, and a lip 614 positioned along the bottom and top, respectively of the moldboard 636. Lip 614 is positioned adjacent an upper surface 615 of the moldboard.
The pallet fork 602 includes a tine or work portion 624, a portion of which is shown in FIGS. 5 and 6 and a mounting or engagement portion 626. The mounting or engagement portion is configured to engage an implement carrier, in this case blade 608. In exemplary embodiments, the engagement portion 626 is a unitary assembly. The unitary engagement portion assembly 626 can be made from any suitable material, but in exemplary embodiments is steel. Because the engagement portion of pallet fork 602 is a unitary assembly configured to engage blade 608, separate attachment or securing mechanisms are not required to mount the pallet fork onto blade 608. In turn, the pallet fork can be made to be stronger or more durable than some conventional pallet forks and can be fabricated less expensively than some conventional pallet forks.
In pallet fork 602, a lip engagement member 616 includes material that is formed to include two adjacent contact areas 630 and 631, which engage adjacent portions of the blade 608, including the lip 614 of blade 608 and upper surface 615 of the moldboard 636. To aid in the engagement of pallet fork 602 without separate attachment mechanisms, contact areas 630 and 631 are not collinear or parallel with one another in an exemplary embodiment. Further, in some exemplary contact areas 630 and 631 are orthogonal or substantially orthogonal with one another, although the intersection of contact areas 630 and 631 may include a radius. An angle between contact areas 630 and 631 of less than 90° can also be used. The lip engagement member also includes a tab 632, which provides some retention force when the pallet fork 602 is engaged with the blade 608 as is shown in FIG. 6. Thus, tab 632 can also be referred to as a retention member. Retention member 632 is positioned opposing the contact area 631. Tab or retention member 632 has an inner edge 635, which is also non-collinear with contact area 630 such that it forms a corner region 633 of the retention member between contact 630 and edge 635. In exemplary embodiments, contact area 630 and edge 635 are oriented at an angle that is significantly less than 90°. There is a gap 634 between an end of the tab 632 and the rest of the blade 608 so that the lip 614 can be accepted into the lip engagement member 616 through the gap. As shown in FIG. 6, when the engagement portion 626 of pallet fork 602 is fully engaged with blade 608, lip 614 of blade 608 is in contact with contact area 630 and upper surface 615 of moldboard 636 is in contact with contact area 631. However, border 635 of retention member 632 has little or no contact with blade 608. When the pallet fork 602 is engaged with the blade assembly 606, the lip engagement member 616 hangs over and surrounds a portion of the lip 614.
The pallet fork 602 includes a face 618 and a protrusion 620. The face 618 is positioned such that when the pallet fork 602 is engaged with the blade 608, the face 618 is not in contact with moldboard 636. The pallet fork 602 also includes a cutting edge contact area 628, which is configured to be in contact with the cutting edge 612 when the pallet fork 602 is engaged with the blade 608. As is shown in FIG. 6, at least a portion of the tine 624 is positioned below the cutting edge, although alternatively, the pallet fork 602 can be structured to be entirely above or below the bottom of the cutting edge 612. Thus, in the illustrative embodiment, contact areas 630 and 631 and cutting edge engagement contact areas 628 represent first, second and third contact areas of the engagement member that engage and abut portions of the blade 608 when the pallet fork 602 is accepted onto blade 608. In some instances, when a load is applied to the work portion, the load can cause contact area 631 to lose contact with the upper surface 615 of the moldboard. Instead, contact area 630, corner region 633, and cutting edge engagement contact area 628 represent first, second and third contact areas of the engagement portion 626 that abut surfaces of the blade 608. In other instances, such as when the work portion 624 encounters an obstacle, the pallet fork 602 can temporarily rotate back. However, the retention member 632 may engage the lip 614 and prevent the pallet fork 602 from being disengaged from the blade 608. It should be appreciated that the portions of the blade 608, namely, the lip 614 and the upper surface 615 of the moldboard 636 and cutting edge 612, to which the contact areas of engagement portion 628 abut when the pallet fork 602 is hung over the blade 608 are generally planar surfaces. It should be further appreciated that the geometric shape of the engagement portion 628, as described above, corresponds with the blade 602 to allow the pallet fork 602 to be engaged with the blade 608 without any sort of actuable locking mechanism on the blade 608 or the pallet fork 602 provided to hold the pallet fork 602 to the blade 608.
While the embodiments above discuss pallet forks, it should be understood that other implements that can be positioned on the host implement of a power machine such as an excavator have been contemplated. The embodiments disclosed above are illustrative in nature and one skilled in the art would appreciate that changes can be made in form and detail without departing from the spirit and scope of the present discussion.
Patent Application
20120207576
