US20230304252A1

US20230304252A1 - Compact utility loader with synchronized lift and extension of working tool attachment

Info

Publication number: US20230304252A1
Application number: US18/024,859
Authority: US
Inventors: John Paul Azure; Joseph Paul Hager
Original assignee: Toro Co
Current assignee: Toro Co
Priority date: 2020-09-08
Filing date: 2021-09-07
Publication date: 2023-09-28
Also published as: EP4211313A1; AU2021341818A1; WO2022055856A1

Abstract

A utility loader incorporating a boom of adjustable length. The boom includes either or both of a left and right arm assembly, with each lift arm assembly including a rear lift arm telescopingly engaged with a front lift arm. Each lift arm assembly also includes an extension actuator adapted to variably extend and retract the front lift arm relative to the rear lift arm. The lift arm assembly includes a connection point to, e.g., receive a tool assembly, and the motion of the lift arm assembly is synchronized to move the connection point along a predetermined path. In one or more embodiments, the predetermined path includes moving along a direction that is normal to the ground surface.

Description

The present application claims priority to and/or the benefit of U.S. Provisional Patent Application No. 63/075,496, filed Sep. 8, 2020, which is incorporated herein by reference in its entirety.
Embodiments of the present disclosure relate to stand-on or walk-behind utility loaders and to such loaders having variable length lift arms.

BACKGROUND

Compact utility loaders, e.g., controlled by a stand-on or walk-behind operator (such loaders being referred to herein as “SOWB loaders”), are known for performing various types of work in an outdoor environment. While able to perform the types of work often associated with large skid steer loaders, compact utility loaders are generally smaller in size (i.e., compact utility loaders). Often, compact utility loaders are operated by an operator who stands on a platform attached to the rear of the loader or, alternatively, walks on the ground behind the loader. However, in one or more embodiments, utility loaders may carry an operator in a seated position, similar to larger skid steer loaders.
While effective for their intended purpose, compact utility loaders are sometimes constrained in operation by their size and, in particular, by the limited reach of the lift arms.

SUMMARY

Embodiments of the present disclosure may provide a compact utility loader that includes: a chassis carrying a prime mover; ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface; and a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis. The loader may also include a lift arm assembly movably attached to the chassis, wherein the lift arm assembly is adapted to move at least between a first position and a second position different than the first position, wherein the lift arm assembly comprises: an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis; and an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly. Also, the loader may include a controller adapted to move the lift arm assembly such that the connection point moves in only a direction normal to the ground surface when moving between the first and second positions.
Another embodiment of the present disclosure may provide a compact utility loader that includes: a chassis carrying a prime mover; ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface; and a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis. The loader may also include a lift arm assembly attached to the chassis, wherein the lift arm assembly comprises: an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis; a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis; an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm. Also, the loader may include a controller adapted to extend or retract the extension actuator in concert with movement of the lift cylinder to maintain movement of the connection point along a predetermined path.
Yet another embodiment of the present disclosure may provide a method of moving a lift arm assembly of a compact utility loader, the method includes: providing the compact utility loader, wherein the compact utility loader comprises: a chassis carrying a prime mover; ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface; a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis; and a lift arm assembly attached to the chassis. The lift arm assembly may include an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis; a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis; an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm. The method may also include extending or retracting the lift actuator to move the elongate rear lift arm relative to the chassis; and automatically extending or retracting the extension actuator in concert with extending or retracting the lift actuator to maintain the connection point in a vertical plane.
The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description of Exemplary Embodiments and claims in view of the accompanying figures of the drawing.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING

Exemplary embodiments will be further described with reference to the figures of the drawing, wherein:

FIG. 1 is a side elevation view of a compact utility loader in accordance with one embodiment of this disclosure, the loader shown with left and right lift arm assemblies supporting a working tool attachment (e.g., a bucket) at a minimum or fully lowered position, the lift arm assemblies further shown in a fully retracted position;

FIG. 2 is a side elevation view of the loader of FIG. 1 (e.g., lift arm assemblies fully retracted), but with the lift arm assemblies lifted to an elevated horizontal position;

FIG. 3 is a side elevation view of the loader of FIG. 1 (e.g., lift arm assemblies fully retracted), but with the lift arm assemblies lifted to a raised position;

FIG. 4 is a perspective view of the loader of FIG. 3 ;

FIG. 5 is a side elevation view similar to FIG. 2 (e.g., lift arm assemblies at an elevated horizontal position), but with the lift arm assemblies in an extended position;

FIG. 6 is a side elevation view similar to FIG. 3 (e.g., lift arm assemblies at a raised position), but with the lift arm assemblies shown in an extended position;

FIG. 7 is a perspective view of the loader of FIG. 6 ;

FIG. 8 is a schematic representation of an illustrative loader including a controller operably coupled to the lift actuators, the extension actuators, and the tilt actuators;

FIG. 9A is a schematic representation of an illustrative loader including a lift arm assembly lifted to an elevated horizontal position and a connection point for a working tool attachment positioned in a vertical plane;

FIG. 9B is a schematic representation of the loader of FIG. 9A showing the lift arm assembly moving to a raised position and the connection point for the working tool attachment maintaining a position within the vertical plane;

FIG. 9C is a schematic representation of the loader of FIG. 9A showing the lift arm assembly moving to a lowered position and the connection point for the working tool attachment maintaining a position within the vertical plane;

FIG. 9D is a schematic representation of the loader of FIG. 9A showing the lift arm assembly moving from a raised position to the elevated horizontal position and the connection point for the working tool attachment maintaining a position within the vertical plane;

FIG. 9E is a schematic representation of the loader of FIG. 9A showing the lift arm assembly moving from a lowered position to the elevated horizontal position and the connection point for the working tool attachment maintaining a position within the vertical plane;

FIG. 10 is a cross sectional view taken along line 10-10 of FIG. 7 ;

FIG. 11 is a perspective view of an exemplary control console for use with a compact utility loader in accordance with embodiments of this disclosure;

FIG. 12 is a perspective view of a portion of the control system of FIG. 11 illustrating a boom control joystick; and

FIG. 13 is a perspective view of a compact utility loader in accordance with another embodiment of the disclosure, wherein the loader includes a single, offset lift arm assembly.

The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure/components, including but not limited to fasteners, electrical components (wiring, cables, etc.), and the like, may be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structure/components is not necessary to an understanding of the various exemplary embodiments described herein. The lack of illustration/description of such structure/components in a particular figure is, however, not to be interpreted as limiting the scope of the various embodiments in any way.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other embodiments, which may not be described and/or illustrated herein, are certainly contemplated.
All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified. Moreover, unless otherwise indicated, all numbers expressing quantities, and all terms expressing direction/orientation (e.g., vertical, horizontal, parallel, perpendicular, etc.) in the specification and claims are to be understood as being modified in all instances by the term “about.” Furthermore, the terms “comprises” and variations thereof do not have a limiting meaning where these terms appear in this description and claims, and the terms “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably herein.
Still further, relative terms such as “left,” “right,” “front,” “fore,” “forward,” “rear,” “aft,” “rearward,” “top,” “bottom,” “side,” “upper,” “lower,” “above,” “below,” “horizontal,” “vertical,” and the like may be used herein and, if so, are from the perspective of one operating the loader 100 while the loader is in an operating configuration, e.g., while it is positioned such that tracks 116 rest upon a generally horizontal ground surface 101 as shown in FIG. 1 . These terms are used only to simplify the description, however, and not to limit the interpretation of any embodiment described.
Embodiments described and illustrated herein are directed to a utility loader (e.g., a compact utility loader) that accommodates an operator either: standing upon a platform attached to the loader (e.g., at a back end of the loader), walking behind the loader. For example, such loaders having an operator standing upon a platform or walking behind the loader may be referred to herein as a “SOWB loader.” In one or more embodiments, the utility loaders described herein may include an operator seated on the loader and may be described as sit-down/sit-in and/or ride-on. Further, for example, the utility loader described herein may include small articulated loaders and/or conventional skid-steer loaders.
The utility loaders described herein may include a boom for supporting and operating various attachments or working tools. However, unlike most compact utility loaders, loaders as described herein may include a boom that not only pivots relative to a frame of the loader, but may also effectively change length as needed. As a result, loaders are provided having improved tool reach and elevation. Furthermore, the utility loaders described herein may include a mode/configuration in which the tool assembly is lifted along a predetermined path (e.g., along a particular radius, an operator's preferred path, a generally vertical path, etc.). For example, in one or more embodiments, the tool assembly may be lifted in only a direction normal to the ground surface (e.g., a generally vertical direction) such that the tool assembly may be lifted relative to a vertical barrier without contacting the barrier. The predetermined path of the tool assembly may be provided to accomplish a variety of different goals such as, e.g., reaching maximum reach/height while raising, avoiding obstacles, maintaining set distance from external structures, etc.
With reference to the figures of the drawing, wherein like reference numerals designate like parts and assemblies throughout the several views, FIGS. 1-4 illustrate a loader 100 in accordance with embodiments of the present disclosure. The loader 100 may be similar in some respects to the Dingo TX series utility loader sold by The Toro Company of Minneapolis, MN, USA. The loader 100 may accommodate a variety of working tools or attachments used, e.g., by landscape contractors, to perform various tasks. For example, a bucket 200 can be attached to the loader 100 for scooping, carrying, and emptying (e.g., into a dump truck) dirt or other material. The loader 100 may accommodate other tools including, for example, forks, a vibratory plow, a grapple rake, a trencher, a leveler, a box rake, a soil cultivator, a snowthrower, a stump grinder, a tiller, an auger, and a plow blade among others.
While utility loaders like those described herein may vary in size, an exemplary compact utility loader in accordance with embodiments of the present disclosure may be of a size that permits the loader to access areas generally inaccessible by larger skid steer loaders (e.g., areas with confined entries such as gates, or areas unable to support the weight of a typical skid steer loader). For example, a compact utility loader like that shown in FIG. 1 may have a fore-and-aft, ground engagement contact pad K (e.g., ground/track engagement) of 60 inches or less, an overall length L (without tool) of 110 inches or less, a height N of 80 inches or less, and a maximum width O (see FIG. 4 ) of 60 inches or less. For instance, the loader 100 of FIG. 1 may have a ground engagement contact pad K of 50 inches, a length L of 103 inches (and a length M of 130 inches with the bucket 200 attached), a height N of 61 inches (corresponding to a height of 67 inches at the top of the carrier 115), and a width O of 54 inches. However, such specific dimensions are exemplary only and loaders of other sizes are certainly contemplated within the scope of this disclosure.
The exemplary loader 100 may be configured in a stand-on configuration using a platform 202 (see FIG. 4 ) to accommodate a standing operator 203. In other embodiments, the platform 202 could be stowable so as not to interfere with walk-behind operation. One embodiment of such a stowable platform is shown in U.S. Pat. No. 7,980,569.
The loader 100 may include a suitably shaped chassis or frame (e.g., lift frame 102) on which a prime mover, such as an internal combustion engine 104, is carried. A hood or shroud 106 may at least partially enclose the engine 104. The lift frame 102 may include laterally spaced uprights 108 on each (left and right) side of the loader. The lift frame 102 may support a boom that includes left and right lift arm assemblies 110 (110 a, 110 b, see also FIG. 4 ). The left and right lift arm assemblies 110 a, 110 b may each include a rear end pivotally connected to the left and right sides or uprights 108 a, 108 b of the lift frame 102, respectively, and extend generally forward of a front end of the loader 100. A lift actuator 112, e.g., hydraulic cylinder (only cylinder 112 a visible in FIG. 1 , but see cylinder 112 b in FIG. 4 ), may be connected between the lift frame 102 and each lift arm assembly 110 (e.g., between the lift frame 102 and a front end of a rear lift arm 150 as illustrated herein). When piston rods of the lift actuators 112 are extended, the lift arm assemblies 110 may pivot about a transverse lift arm pivot axis 113 to raise or lift distal (e.g., front) ends of the lift arm assemblies 110 relative to the ground surface 101/lift frame 102. Likewise, when the piston rods of the lift actuators 112 are retracted, the lift arm assemblies 110 may pivot in the opposite direction about the transverse lift arm pivot axis 113 to lower the distal ends of the arms.
The suffixes “a” and “b” may be used throughout this description to denote various left- and right-side parts/features, respectively. However, in most pertinent respects, the parts/features denoted with “a” and “b” suffixes are substantially identical to, or mirror images of, one another. It is understood that, unless otherwise noted, the description of an individual part/feature (e.g., part/feature identified with an “a” suffix) also applies to the opposing part/feature (e.g., part/feature identified with a “b” suffix). Similarly, the description of a part/feature identified with no suffix may apply, unless noted otherwise, to both the corresponding left and right part/feature.
In the embodiments described and illustrated herein, the various actuators (e.g., the lift actuators 112, extension actuators 154 (described below), and tilt actuators 124 (also described below)) may be configured as hydraulic cylinders. However, the term “actuator,” as used herein, may refer to most any electric, hydraulic, or pneumatic device capable of providing movement of one element relative to another. For example, a linear electric actuator, or a hydraulic or electric rotary motor driving a pinion in a rack-and-pinion system, may be utilized in place of the hydraulic cylinders described herein without departing from the scope of this disclosure.
The loader 100 may further include a traction system that includes both left and right ground engaging members that, in one embodiment, are formed by tracks 116 (only left track visible in FIG. 1 , but right track (and track frame) is a mirror image) operatively attached to the lift frame 102 (while shown as tracks, other embodiments may use ground-engaging wheels or any other device capable of providing propulsion power to the loader). In one or more embodiments, the loader may include left and right track frames 130 that support the left and right tracks 116, respectively, wherein the track frames 130 may be operatively attached to the lift frame 102. For example, each track frame 130 may be pivotally attached to the lift frame 102 via a front mounting shaft defining a front pivot axis 132 (see FIG. 1 ) located proximate a front end of the lift frame 102. As such, the lift frame 102 may pivot during operation relative to the track frame 130 about the front pivot axis 132.
With reference still to FIGS. 1-4 , each track 116 may be connected to its own, independent drive unit (e.g., hydraulic motor) powered by the engine 104 such that the loader may be propelled over the ground surface 101. In the illustrated embodiments, each track 116 may be configured as an endless, flexible belt that is looped or entrained around a plurality of idlers 119 and a drive wheel 118, the latter being at an elevation above the idlers. Each track 116 may include inwardly extending drive lugs that engage apertures or openings formed in at least the drive wheel 118 so that rotation of the drive wheel 118 results in linear movement of the track 116. In other embodiments, each drive wheel 118 could instead define a sprocket with sprocket teeth operable to engage notches formed in the associated track 116. In fact, most any track configuration now known or later developed is possible without departing from the scope of this disclosure. As stated above, in still other embodiments, the tracks 116 could be replaced with wheels.
As is known in the art, each hydraulic motor may rotate its respective drive wheel 118 in either a forward or reverse direction to permit corresponding propulsion of the loader 100 forwardly (to the left in FIG. 1 ) or rearwardly (to the right in FIG. 1 ). As each drive wheel 118 may be powered by its own independent motor, steering control of the loader 100 may be achieved by varying the relative rotational speed and direction of each drive wheel, and thus the speed and direction of each track 116.
The loader 100 may further include a control console 120 (see FIGS. 4 and 10 ) that, in the illustrated embodiment, is located at or near the rear end of the loader 100 (e.g., at or near the rear end of the lift frame 102) proximate the upper ends of the uprights 108. The control console 120 may include various controls, e.g., levers, switches, buttons, etc., that control loader operation. For example, the control console 120 may include controls that cause various actuators to energize (e.g., cause lift actuators 112 to extend and thus pivot the lift arm assemblies 110 from a lowered position (FIG. 1 ) through an intermediate elevated position (e.g., see FIG. 2 ) to a maximum elevated position (see FIG. 3 )). In addition, the control console 120 may include a movable drive control handle to allow operator control of the traction system that drives the tracks 116. One exemplary control system that may be adapted for use with embodiments of the present disclosure is described in detail in U.S. Pat. App. Publ. No. 2016-0244937.
As mentioned above, working tools (e.g., such as bucket 200) may be connected to a mounting structure, e.g., attachment plate 122, pivotally connected to front or distal ends of the lift arm assemblies 110. To ease the task of removing and installing tools on the attachment plate 122, various quick attachment systems may be used as are known in the art. Such attachment plates may conform to industry standards such as SAE J2513 (2000).
In some embodiments, the attachment plate 122 is pivotally connected to the front ends of the lift arm assemblies (e.g., at a connection point 123) so that an orientation (e.g., angle of inclination) of the attachment plate (and thus the tool itself) may be adjusted as the lift arm assemblies are raised and lowered. In one or more embodiments, the connection point 123 may be described as a transverse pivot joint/axis. Tilt actuators 124 (124 a, 124 b, see FIG. 4 ), which may be configured as left and right hydraulic cylinders, may extend between the attachment plate 122 and the lift arm assemblies 110. As the tilt actuators 124 extend and retract, the angle of inclination of the attachment plate (about the connection point 123 and relative to lift arm assemblies) may change. Thus, by controlling the vertical position of the lift arm assemblies 110 (via the lift actuators 112), and by controlling the angle of inclination of the attachment plate 122 (via the tilt actuators 124) relative to the lift arm assemblies, the operator may position the tool within a wide range of elevations and inclinations. While shown as utilizing two tilt actuators 124, other embodiments may use a single tilt actuator, or event three or more tilt actuators without departing from the scope of this disclosure.
During operation, the operator may stand upon the platform 202 as shown in the figures (or, in other embodiments, walk behind the lift frame 102). The control console 120 may be positioned at a convenient height so that it remains accessible to the operator from this standing position. In combination with the forward location of the lift arm pivot axis 113, utility loaders may provide the operator with desirable sight lines to both the tool area and the areas immediately surrounding the operator.
Advantageously, loader 100 may use laterally offset (laterally offset to the left and right from a longitudinal axis 111 (see FIG. 4 ) of the loader/lift frame) lift arm assemblies (or, as described below, a single, offset lift arm assembly) and an operator position that is generally centered between the left and right lift arm assemblies 110 a, 110 b. Such a configuration (as well as configurations using a single offset arm as described below) may allow less obstructed visibility of the tool area when compared to, for example, loader configurations utilizing a single, centered arm. Furthermore, offset arms allow the engine 104 to be located at various longitudinal positions between (e.g., lateral to) the lift arm assemblies 110. Such versatility with engine positioning may allow tuning of loader weight distribution/center of gravity characteristics and thus reduce or avoid the need to add additional counter-weights to the vehicle. Again, visibility may also benefit from positioning the operator 203 (i.e., the operator platform 202) behind (aft of) the transverse lift arm pivot axis 113.
With reference again to FIG. 1 , the operator may cause the loader 100 to pick up a load of material (e.g., dirt, debris, etc.) with the bucket 200 and then elevate the bucket to an intermediate or transport position (e.g., an elevated horizontal position) as shown in FIG. 2 . Movement to the elevated horizontal position of FIG. 2 may be accommodated by a control located on the control console 120 (see, e.g., FIG. 11 and accompanying description below) that causes the actuators 112 to extend, thereby raising the bucket 200 to the position shown in FIG. 2 . If necessary, the operator may also command the bucket 200 to tip rearwardly by retracting the tilt actuators 124 (see FIG. 4 ). In some embodiments, the loader may include a controller adapted to adjust the tilt actuators 124 as the lift actuators 112 are extended to maintain the bucket in a generally constant orientation.
As the loader 100 approaches an elevated dump location (e.g., dump truck or other elevated surface), the bucket 200 may be raised to a higher position as shown in FIGS. 3 and 4 by further extending the lift actuators 112 as shown. To dump the bucket contents, the tilt actuators 124 may be extended.
While not wishing to be bound to any particular embodiment, the exemplary loader 100 may provide lift arm assemblies 110 that (when retracted as shown) can pivot to the maximum raised position as shown in FIG. 3 . When in this position, the lift arm assemblies 110 may be oriented at an angle E measured from horizontal of 35-40 degrees (e.g., 37 degrees). Moreover, the attachment plate 122 (e.g., measured at the connection point 123) may be at an elevation A of 90-100 inches (e.g., 98 inches) yielding a dump height C of 65-75 inches (e.g., 70 inches). When in this maximum raised position, the loader may also have a maximum height G of 100-110 inches (e.g., 106 inches). As FIG. 3 further illustrates, the loader 100 may accommodate these elevations with a horizontal reach B, measured from the forwardmost edge of the loader (e.g., forwardmost edge of the tracks 116) to the forwardmost edge of the bucket 200, of 20-30 inches (e.g., 25 inches), assuming a maximum bucket tilt angle F of 45 degrees. Such an exemplary configuration may also result in a pin reach H (horizontal distance from the forwardmost edge of the frame/track 116 to the connection point 123) of 1-4 inches (e.g., 1 inch). Once again, these dimensions are exemplary only and may vary for other loader configurations.
In order to provide even increased versatility and greater lift and reach, loaders in accordance with embodiments of the present disclosure may further provide boom/lift arm assemblies 110 of variable (e.g., extendible) length as described below and illustrated primarily in FIGS. 5-7 . In the illustrated embodiments, this variable length is achieved by configuring each lift arm assembly (110 a, 110 b) to include both an elongate rear lift arm 150 (having front and rear ends, wherein the rear end is equivalent to the rear end of the arm assembly) and an elongate front lift arm 152 (also having front and rear ends, wherein the front end is equivalent to the front end of the arm assembly). Each front lift arm 152 (e.g., the rear end of each front lift arm) is telescopingly engaged with (e.g., received within) the rear lift arm 150 (e.g., within the front end of the rear lift arm) such that a distance between the rear end of the rear lift arm and the front end of the front lift arm (e.g., a length of the arm assembly) is variable. The rear end of each rear lift arm 150 may be pivotally connected to its respective upright 108 of the lift frame 102 at the lift arm pivot axis 113. In one embodiment, each rear lift arm 150 forms a tubular member (e.g., a rectangular tube having a greater dimension in the vertical or lift direction), wherein the respective front lift arm 152 may be received therein such that the front lift arm 152 may translate along and within the rear lift arm 150 from a fully retracted position (see, e.g., FIG. 2 ), to a fully extended position or any intermediate position therebetween.
While described as being a tubular member that receives the front lift arm 152 therein, those of skill in the art will realize that the shape of the rear lift arm 150 does not necessarily need to define an enclosed cross section. For example, alternative embodiments of the rear lift arm 150 may form a U- or C-channel in cross section without departing from the scope of this disclosure. In fact, any shape that permits the translation of the front lift arm 152 relative to the rear lift arm 150, while also providing the needed structural integrity to allow the lift arm assemblies 110 to lift the predetermined load when fully extended, is contemplated.
To extend and retract the lift arm assemblies 110 a, 110 b, each may include an extension actuator 154 (154 a, 154 b, see FIG. 7 ) adapted to extend and retract the front lift arm 152 relative to the rear lift arm 150. In the illustrated embodiment, each extension actuator 154 is configured as a linear hydraulic cylinder having a rear (cylinder) end attached to the rear lift arm 150, and a forward (piston rod) end attached to the front lift arm 152. By extending the extension actuators 154 in unison, the lift arm assemblies 110 may extend from their fully retracted positions shown in FIGS. 1-4 , to extended positions shown in FIGS. 5-7 . In the illustrated embodiment, the lift arm assemblies may extend by a distance J (see FIG. 6 ) of 30-35 inches (e.g., 31 inches).
By allowing the lift arm assemblies 110 to extend from the length provided in the retracted position, the reach and lift height of the loader 100 may be increased accordingly. For example, with the lift arm assemblies 110 in the extended and raised position as shown in FIG. 6 , the attachment plate 122 (e.g., the connection point 123) can now reach an elevation A of 120-130 inches (e.g., 123 inches) yielding a dump height C of 90-100 inches (e.g., 95 inches). As this figure further illustrates, the loader 100 may accommodate these elevations with a horizontal reach B now of 50-60 inches (e.g., 58 inches), including a pin reach H of 15-25 inches (e.g., 20 inches). Finally, with the lift arm assemblies 110 extended and raised as shown in FIG. 6 , the maximum height G is now 125-135 inches (e.g., 131 inches).
The loader 100 may also include a controller operatively connected to the control console 120 and adapted to control the lift arm assembly 110. For example, the controller 190 may be operatively coupled to the lift actuators 112, the extension actuators 154, and the tilt actuators 124 to adjust (e.g., extend/retract) each, e.g., as shown in FIG. 8 . Further, the controller may be adapted to execute protocols pertaining to various movements (e.g., extensions and/or retractions) of the lift actuators 112, the extension actuators 154, and the tilt actuators 124. For example, the lift arm assembly 110 may be configurable in a variety of different modes/configurations such that the actuators move in a synchronized manner. Specifically, the modes/configurations may provide for the lift arm assembly moving along a predetermined path by extending/retracting a combination of the lift actuators 112, the extension actuators 154, and the tilt actuators 124.
In some embodiments, the loader 100 may include one or more sensors 196, e.g., as shown in FIG. 8 . The one or more sensors 196 may be operably connected the controller 190 and adapted to determine the position and/or orientation of the lift arm assembly 110. For example, the one or more sensors 196 may sense the rod position and/or hydraulics of each of the actuators (e.g., the lift actuators 112, the extension actuators 154, and the tilt actuators 124) and/or determine the angle of the lift arm assembly 110. As shown in FIG. 8 , each actuator may include a corresponding sensor 196. In other embodiments, the one or more sensors 196 may include a single sensor or any suitable number of sensors. For example, in one or more embodiments, the one or more sensors 196 may be located in the pivot pins about which the lift arm assembly 110 pivots relative to the chassis (e.g., to determine the current angle of the lift arm assembly 110). Further, the one or more sensors 196 may be configured to sense the location of the cylinder/actuator arms relative to each other (e.g., the cylinder stroke) to determine the amount of extension or retraction.
The exemplary controller 190 may include a processor 192 that receives various inputs and executes one or more computer programs or applications stored in memory 194. The memory 194 may include computer-readable instructions or applications that, when executed, e.g., by the processor 192, cause the controller 190 to perform various calculations and/or issue commands. That is to say, the processor 192 and memory 194 may together define a computing apparatus operable to process input data and generate the desired output to one or more components/devices.
In view of the above, it will be readily apparent that the functionality of the controller 190 may be implemented in any manner known to one skilled in the art. For instance, the memory 194 may include any volatile, non-volatile, magnetic, optical, and/or electrical media, such as a random-access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, and/or any other digital media. While shown as both being incorporated into the controller 190, the memory 194 and the processor 192 could be contained in separate modules.
The processor 192 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or equivalent discrete or integrated logic circuitry. In some embodiments, the processor 192 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and/or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller 190/processor 192 herein may be embodied as software, firmware, hardware, or any combination thereof.
In one or more embodiments, the operator may desire to move the attachment plate (e.g., adapted to receive a working tool/bucket 200) along a predetermined path. For example, it may be desirable to move the attachment plate in a generally vertical direction (e.g., in a direction normal to the ground surface 101) due to external environmental obstacles. Specifically, the loader 100 may be positioned such that the working tool is proximate a vertical wall or barrier. The operator may desire to lift the working tool without interfering with the wall/barrier (and without moving the loader 100) and, therefore, may lift along a predetermined path (e.g., parallel with the wall/barrier) to avoid contact with the wall/barrier. As such, the controller of the loader 100 may be adapted extend/retract the lift actuators 112 and the extension actuators 154 in a synchronized manner such that working tool moves along that predetermined path (e.g., maintaining verticality in movement).
The connection point 123 may be used as a reference point due to the connection point 123 being an interface between the attachment plate 122 (e.g., which receives the working tool) and the elongate front lift arm 152. Therefore, as shown in FIGS. 2 and 5 , a vertical plane 211 (e.g., normal to the ground surface) is illustrated extending through the connection point 123. However, it is noted that other regions of the elongate front lift arm 152 may be used as a reference point.
In one or more embodiments, the controller may be adapted to configure the lift arm assembly 110 into a synchronized mode such that the lift arm assembly 110 may only move along a predetermined path (e.g. through extension/retraction of the lift actuator 112 and the extension actuators 124). For example, in one or more embodiments, the synchronized mode may configure the lift arm assembly 110 to move in a direction normal to the ground surface 101 (e.g., a generally vertical direction) as described herein. The synchronized mode may be accommodated by a control 182 located on the control console 120 (see, e.g., FIG. 11 ) that causes the lift actuators 112 and the extension actuators 154 (and, e.g., the tilt actuators 124) to extend/retract in concert to move the connection point 123 along the predetermined path (e.g., the vertical plane 211). Further, when the synchronized mode is engaged, the controller ties together the lift actuators 112 and the extension actuators 154 such that when the lift actuators 112 are extended/retracted, the extension actuators 154 are correspondingly extended/retracted to maintain the desired (e.g., vertical) movement of the connection point 123. In other words, the controller 190 may be adapted to automatically move (e.g., extend/retract) the extension actuators 154 in response to movement (e.g., extension/retraction) of the lift actuators 112 (e.g., in coordination therewith) when in the synchronized mode. On the other hand, when the synchronized mode is not engaged (e.g., a manual/default mode), the operator can manually control any appropriate extension/retraction of the lift actuators 112 and the extension actuators 154 independently.
Furthermore, in one or more embodiments, the controller may be adapted to configure the lift arm assembly 110 into a learn mode. For example, the lift arm assembly 110 may learn a specific path of movement from the operator such that the specific path of movement of the lift arm assembly 110 may be carried out automatically thereafter. Therefore, if the operator is carrying out a known or repetitive path of motion for the lift arm assembly 110, the learn mode may synchronize the actuators to automatically move (e.g., in conjunction with the synchronized mode). As such, the lift arm assembly 110 may consistently move along the learned path, when activated by the operator.
In one or more embodiments, the control 182 may include a button that is actuated between engaging and disengaging the synchronized/learn mode (e.g., such that the operator normally raises/lowers the lift actuator 112 to control the predetermined movement). However, in other embodiments, the control 182 may be adapted to control the up and down movement of the connection point 123 through the controller 190 accordingly actuating the lift actuators 112 and the extension actuators 154 (e.g. such that the predetermined movement is fully controlled by the control 182).
Further, in one or more embodiments, when the synchronized mode is engaged, the extension actuator 154 may be restricted/disabled from being manually extended and/or retracted by the operator (e.g., to prevent the operator from extending the working tool in an undesired direction). Although, in one or more embodiments, the extension actuator 154 may be permitted to only retract by manual operation of the operator, when in the mode.
Furthermore, the lift arm assembly 110 may be adapted to move at least between a first position and a second position different than the first position in a prescribed way. For example, the controller may be adapted to move the lift arm assembly 110 such that the connection point 123 moves in only a direction normal to the ground surface 101 when moving between the first and second positions. In other words, the connection point 123 maintains movement in only a generally vertical direction.
In one embodiment, the lift arm assembly 110 may be positioned in a default position on the ground surface 101, e.g., as shown in FIG. 1 . Thereafter, the lift actuators 112 may extend to lift the lift arm assembly 110 such that the elongate rear and front lift arms 150, 152 extend along a generally horizontal plane, e.g., as shown in FIG. 2 . Next, the extension actuators 154 may extend to move the elongate front lift arms 152 away from the chassis 102 and remain in the generally horizontal plane, e.g., as shown in FIG. 5 . The orientation illustrated in FIG. 5 may be described as the first position as previously described herein. It is noted that the extension actuators 154 may not be fully extended at the first position in the synchronized mode (e.g., so that the extension actuators 154 may extend further as the lift arm assembly is raised or lowered). The lift arm assembly 110 may then move to a second position such that the connection point 123 moves in only a direction normal to the ground surface (e.g., generally along vertical plane 211) when moving from the first position to the second position.
To maintain movement of the connection point 123 along a predetermined (e.g., generally vertical) path, the extension/retraction of each of the lift actuators 112 and the extension actuators 154 may be linked to accomplish the predetermined (e.g., vertical) movement. For example, the controller may be adapted to extend or retract the extension actuators 154 simultaneously with the lift actuators 112 such that the connection point maintains movement along a direction normal to the ground surface 101. Specifically, the extension actuator 154 may extend by an inch in response to the operator extending the lift actuator 112 by an inch (e.g., simultaneous extension) to maintain vertical movement of the connection point 123. While this may be one example of the extension/retraction relationship between the lift actuators 112 and the extension actuators 154, it is noted that relationship may not be directly proportional at every position of the lift arm assembly 110. For example, because the lift am assembly 110 is pivotally attached to the chassis 102 and pivots relative to the chassis 102 about an arcuate path, the relationship between pivoting the lift arm assembly 110 and extending/retracting the extension actuators 154 to maintain vertical movement of the connection point 123 may change through the arcuate path.
Specifically, the extension actuators 154 may extend or retract depending on the angle at which the lift arm assembly 110 changes. For example, the distance between the transverse pivot axis 113 (e.g., about which the lift arm assembly 110 pivots) and the connection point 123 may be described as distance Z (e.g., see FIG. 9A). The distance Z may assist in appropriately positioning the loader 100 relative to a barrier or wall (e.g., with also accounting for the size of the tool). The lift arm assembly 110 may be positioned at any angle relative to horizontal (e.g., generally horizontal plane 212 as shown in FIG. 9A) and move between a first angle (e.g., 01) and a second angle (e.g., 02). The amount of extension/retraction of the extension actuators 154 to maintain movement of the connection point 123 along the generally vertical direction 211 (to move from the first angle to the second angle) may be calculated as follows:
extension/retraction=(1/cos(θ2)−1/cos(θ1))*Z (Equation 1)
Further, the amount of extension/retraction of the lift actuators 112 may depend on the specifications and dimensions of the loader 100, but may be calculated using the change in angle of the lift arm assembly 110 (e.g., by using the one or more sensors 196).
Furthermore, the location of the lift arm assembly 110 within the arcuate path may determine the type of movement (extension or retraction) of the lift actuators 112 and the extension actuators 154 that would maintain movement of the connection point 123 in a vertical direction. For example, depending on whether the lift arm assembly 110 is positioned at an angle above or below a generally horizontal plane (e.g., relative to the ground surface 101) may affect the relationship between the lift actuators 112 and the extension actuators 154 (not shown in FIG. 9A, but the extension actuators 154 provide relative movement between the elongate rear lift arm 150 and the elongate front lift arm 152). FIG. 9A illustrates the loader 100 with the lift arm assembly 110 extending along a generally horizontal plane 212 relative to the ground surface 101.
To maintain movement of the connection point 123 in a direction normal to the ground surface 101 (e.g., generally vertical direction/plane 211), the extension actuators 154 and the lift actuators 112 may extend in respective directions 222, 224 when the connection point 123 moves in an upward direction 220 (e.g., see FIG. 9B) from horizontal and the extension actuators 154 may extend in direction 232 and the lift actuators 112 may retract in direction 234 when the connection point 123 moves in a downward direction 230 (e.g., see FIG. 9C) from horizontal. Further, when the lift arm assembly 110 moves from a higher position towards the horizontal plane 212 in direction 240 (e.g., as shown in FIG. 9D), the extension actuators 154 and lift actuators 112 may retract in the respective directions 242, 244 and when the lift arm assembly 110 moves from a lower position towards the horizontal plane 212 in direction 250 (e.g., as shown in FIG. 9E), the extension actuators 154 may retract in direction 252 and the lift actuators 112 may extend in direction 254.
Therefore, in one or more embodiments, the lift arm assembly 110 may be initially positioned such that the tool attached thereto may be proximate the ground surface 101. The lift arm assembly 110 may then be positioned such that the connection point 123 is located at a desired distance relative to the chassis 102 (e.g., within the desired vertical plane). For example, one or both of the extension actuators 154 and the lift actuators 112 may extend to position the connection point 123 in the desired location. From that position, the synchronized mode of the loader 100 may be engaged such that subsequent movement of the lift arm assembly 110 may maintain the connection point 123 within the vertical plane as described herein. In other words, when in the synchronized mode, the extension actuators 154 may automatically move in response to an operator moving the lift actuators 112 such that the connection point 123 maintains movement along the direction normal to the ground surface 101 (e.g., a generally vertical direction).
It is noted that, in one or more embodiments, the height to which the lift arm assembly 110 is raised (and/or extended) may be limited due to load constraints of the loader 100. For example, when the loader 100 is in the synchronized mode, the lift arm assembly 110 may be restricted from lifting to a point at which the loader 100 passes a load constraint threshold. Therefore, actuation of the extension actuators 154 and the lift actuators 112 may stop (e.g., moving the connection point 123 along a generally vertical direction) when reaching a specific point as determined by the controller. While extension of the lift actuators 112 and the extension actuators 154 may be limited when in the synchronized mode, retraction of the lift actuators 112 and the extension actuators 154 may be permitted (e.g. because retraction does not further extend the center of gravity).
In one or more embodiments, one or both of the lift arm assemblies 110 may include at least one carrier 115 (shown only in FIG. 1 ) extending between the rear and front lift arms 150, 152. The carrier 115 may be configured to guide and restrain cables, wires, hoses, etc. extending between the rear lift arms 150/frame 102 and the front lift arms 152 as the lift arm assemblies 110 move between their fully retracted positions and their fully extended positions.
Loaders in accordance with embodiments of the present disclosure may utilize dual lift arm assemblies (e.g., left and right) with corresponding dual actuators. For instance, the loader 100 may include left and right lift actuators 112, left and right tilt actuators 124, and left and right extension actuators 154. Such a dual configuration may, as stated above, provide various benefits including better visibility of the tool area, e.g., along a centerline viewing lane of the loader 100 (as opposed to configurations using a single, centrally-mounted arm assembly/actuator). To ensure even actuation pressures, each actuator may be hydraulically connected in parallel to its corresponding actuator (e.g., lift actuator 112 a is hydraulically connected in parallel to lift actuator 112 b) so that each actuator of each pair receives equal pressure during actuation. In other embodiments, the loader 100 could accommodate the various arm assembly movements using a single lift actuator 112, a single tilt actuator 124, and/or a single extension actuator 154.
In order to avoid binding during extension and retraction of the front lift arms 152 of each lift arm assembly 110, one or both of the front or rear lift arms may include anti-friction pads. For example, in the embodiment illustrated in FIG. 7 , each of the rear lift arms 150 may each include a cap 156, a cross section of which is provided in FIG. 10 (taken along line 10-10 of FIG. 7 ). As shown in this cross section, the inboard side of each cap (as well as other locations along inner surfaces of the rear lift arms) may include wear pads 158 to reduce friction during lift arm extension/retraction. Moreover, along one or more sides (e.g., outboard and top sides) of each cap 156 is a threaded adjuster 160. The adjuster 160 may include a wear pad 159 that may be tightened against the front lift arm 152 by turning a head 162 of the adjuster. As a result, undesired clearances between the front and rear lift arms 152, 150 may be minimized by periodic tightening of the adjusters 160.
The wear pads 158, 159 may be made of most any acceptable bearing material. For example, the pads may include thermoplastic resins such as Delrin acetyl resin distributed by E. I. du Pont de Nemours and Company of Wilmington, Delaware, USA. Other potential wear pad materials include ultra-high molecular weight (UHMW) polyethylene, nylon, and powdered metal, to name a few.
FIGS. 11-12 illustrate the control console 120 in accordance with embodiments of the present disclosure. As shown in FIG. 11 , the console may include directional control levers 171 (171 a, 171 b) operable to intuitively control the ground speed and direction of the loader 100. In this embodiment, the control levers may be connected via a T-shaped handle 170 that may be displaced forwardly and rearwardly (to drive the loader forwardly and rearwardly, respectively), and/or twisted clockwise (for a right turn) or counterclockwise (for a left turn). The control console 120 may also include multiple switches for various other purposes (e.g., to engage the synchronized mode). For example, the control console 120 may include a throttle switch 180 and a brake enable switch 121. Further, as described herein, the control console 120 may also include a synchronized mode control 182.
Accessible with the opposite hand is a joystick 172 that may intuitively control operation of the boom. An enlarged view of the joystick 172 is shown in FIG. 12 . As shown in this view, the joystick 172 may include controls to manipulate (e.g., retract/lower and extend/lift) the lift arm assemblies 110 (e.g., via the lift actuators 112 and extension actuators 154). For example, the joystick may be pushed forwardly (e.g., in the direction 175) to lower the boom (e.g., retract the lift actuators 112), and pulled rearwardly (e.g., in the direction 176) to lift or raise the boom (e.g., extend the lift actuators). Moreover, the tilt actuators 124 may be controlled by left and right movement of the joystick 172. For instance, movement of the joystick to the left (e.g., in the direction 178) may cause the tilt actuators 124 to retract and curl the bucket 200, while movement to the right (e.g., in the direction 177) may cause the tilt actuators to extend and dump the contents of the bucket. Still further, the joystick 172 may include a thumb-actuated rocker switch 174 that may be pressed near its top to extend the extension actuators 154, or near the bottom to retract the extension actuators 154. Other controls may also be incorporated into the joystick 172 as shown in FIG. 12 , or into other areas of the control console 120 as shown in FIG. 11 . For example, the synchronized mode may be selected or manipulated using control 182 (e.g., a switch on the control console 120).
While described herein as utilizing two (left and right) lift arm assemblies, other embodiments may achieve the desired lift and reach using a single laterally offset lift arm assembly. Such an arm assembly could be attached to either the left or right side of the loader (e.g., similar to using only one of the arm assemblies illustrated herein). For example, as shown in FIG. 13 , a loader 400 is shown that includes a lift arm assembly 410 that may be attached to a lift frame 402 on the left side of the loader 400. The offset position of the lift arm assembly 410 may, as with the dual arm loader 100 described above, allow the operator of the loader 400 to maintain visibility of the tool area through the center of the loader 400. The lift arm assembly 410 may include an elongate rear lift arm 450 pivotally attached to the lift frame 402 and an elongate front lift arm 452 that may be telescopingly received in the rear lift arm 450 in a manner similar to that already described herein in the context of the loader 100. For example, a rear end of the front lift arm 452 may be telescopingly received in a front end of the rear lift arm 450 such that a distance between a rear end of the rear lift arm 450 and a front end of the front lift arm 452 may be varied. The loader 400 may also include any of the features already identified and described herein in accordance with the embodiments of FIGS. 1-12 .
The complete disclosure of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. In the event that any inconsistency exists between the disclosure of the present application and the disclosure(s) of any document incorporated herein by reference, the disclosure of the present application shall govern.
Illustrative embodiments are described and reference has been made to possible variations of the same. These and other variations, combinations, and modifications will be apparent to those skilled in the art, and it should be understood that the claims are not limited to the illustrative embodiments set forth herein.

ILLUSTRATIVE EMBODIMENTS

While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the specific examples and illustrative embodiments provided below. Various modifications of the examples and illustrative embodiments, as well as additional embodiments of the disclosure, will become apparent herein
A1. A compact utility loader comprising:
a chassis carrying a prime mover;
ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface;
a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis;
a lift arm assembly movably attached to the chassis, wherein the lift arm assembly is adapted to move at least between a first position and a second position different than the first position, wherein the lift arm assembly comprises:

- an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis; and
- an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and

a controller adapted to move the lift arm assembly such that the connection point moves in only a direction normal to the ground surface when moving between the first and second positions.
A2. The compact utility loader according to any A embodiment, wherein the lift arm assembly further comprises an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm, wherein the extension actuator extends outward to the first position and then the connection point moves vertically to the second position.
A3. The compact utility loader according to any A embodiment, wherein the lift arm assembly further comprises:
an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm, and
a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis,
wherein the extension actuator extends or retracts at the same time as the lift actuator extends or retracts to move the connection point along a direction normal to the ground surface between the first and second positions.
A4. The compact utility loader according to embodiment A3, wherein the controller is adapted to restrict operator extension of the extension actuator.
A5 The compact utility loader according to any A embodiment, wherein the lift arm assembly is configurable in a synchronized mode and a manual mode, wherein the controller is adapted to move the lift arm assembly from the first position to the second position when in the synchronized mode.
A6. The compact utility loader according to any A embodiment, wherein the prime mover is positioned on the chassis at a location lateral to the lift arm assembly.
B1. A compact utility loader comprising
a chassis carrying a prime mover;
ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface;
a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis;
a lift arm assembly attached to the chassis, wherein the lift arm assembly comprises:

- an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis;
- a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis;
- an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and
- an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm; and

a controller adapted to extend or retract the extension actuator in concert with movement of the lift actuator to maintain movement of the connection point along a predetermined path.
B2. The compact utility loader according to any B embodiment, wherein extension actuator extends when the lift actuator extends to maintain movement of the connection point along a direction normal to the ground surface.
B3. The compact utility loader according to any B embodiment, wherein extension actuator retracts when the lift actuator retracts to maintain movement of the connection point along a direction normal to the ground surface.
B4. The compact utility loader according to any B embodiment, wherein extension actuator extends when the lift actuator retracts to maintain movement of the connection point along a direction normal to the ground surface.
B5. The compact utility loader according to any B embodiment, wherein extension actuator retracts when the lift actuator extends to maintain movement of the connection point along a direction normal to the ground surface.
B6. The compact utility loader according to any B embodiment, wherein the extension actuator extends prior to maintaining movement of the connection point along the predetermined path.
B7. The compact utility loader according to any B embodiment, wherein the lift arm assembly is configurable in a synchronized mode and a manual mode, wherein the controller is adapted to move each of the lift actuator and the extension actuator such that the connection point maintains movement along the predetermined path when in the synchronized mode.
B8. The compact utility loader according to any B embodiment, wherein the prime mover is positioned on the chassis at a location lateral to the lift arm assembly.
B9. The compact utility loader according to any B embodiment, wherein the controller is adapted to restrict operator extension of the extension actuator.
C1. A method of moving a lift arm assembly of a compact utility loader, the method comprising:
providing the compact utility loader, wherein the compact utility loader comprises:

- a chassis carrying a prime mover;
- ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface;
- a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either:

standing on a platform mounted near the rear end of the chassis; or walking behind the chassis; and

- a lift arm assembly attached to the chassis, wherein the lift arm assembly comprises:
  - an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis;
  - a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis;
  - an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and
  - an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm;
- extending or retracting the lift actuator to move the elongate rear lift arm relative to the chassis; and
- automatically extending or retracting the extension actuator in concert with extending or retracting the lift actuator to maintain the connection point in a vertical plane.
  C2. The method according to any C embodiments, further comprising positioning the connection point in the vertical plane prior to automatically extending or retracting the lift actuator and the extension actuator.
  C3. The method according to embodiment C2, wherein positioning the connection point in the vertical plane comprises manually extending or retracting one or both of the lift actuator and the extension actuator.
  C4. The method according to embodiment C2, further comprising positioning the lift arm assembly along a generally horizontal plane relative to the ground surface prior to automatically extending or retracting the lift actuator and the extension actuator.
  C5. The method according to any C embodiment, further comprising restricting operator extension of the extension actuator.

Thus, various embodiments described herein are disclosed. It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a utility loader.

Claims

1. A compact utility loader comprising:

a chassis carrying a prime mover;

ground engaging members operatively attached to the chassis, wherein at least one of the ground engaging members is powered by the prime mover to propel the chassis over a ground surface;

a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis;

a lift arm assembly movably attached to the chassis, wherein the lift arm assembly is adapted to move at least between a first position and a second position different than the first position, wherein the lift arm assembly comprises:

an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis; and

an elongate front lift arm also including a front end and a rear end, wherein the rear end of the front lift arm is telescopingly engaged with the front end of the rear lift arm such that a distance between the rear end of the rear lift arm and the front end of the front lift arm is variable, wherein the elongate front lift arm comprises a connection point adapted to receive a tool assembly; and

a controller adapted to move the lift arm assembly such that the connection point moves in only a direction normal to the ground surface when moving between the first and second positions.

2. The compact utility loader of claim 1, wherein the lift arm assembly further comprises an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm, wherein the extension actuator extends outward to the first position and then the connection point moves vertically to the second position.

3. The compact utility loader of claim 1, wherein the lift arm assembly further comprises:

an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm, and

a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis,

wherein the extension actuator extends or retracts at the same time as the lift actuator extends or retracts to move the connection point along a direction normal to the ground surface between the first and second positions.

4. The compact utility loader of claim 3, wherein the controller is adapted to restrict operator extension of the extension actuator.

5. The compact utility loader of claim 1, wherein the lift arm assembly is configurable in a synchronized mode and a manual mode, wherein the controller is adapted to move the lift arm assembly from the first position to the second position when in the synchronized mode.

6. The compact utility loader of claim 1, wherein the prime mover is positioned on the chassis at a location lateral to the lift arm assembly.

7. A compact utility loader comprising:

a chassis carrying a prime mover;

a lift arm assembly attached to the chassis, wherein the lift arm assembly comprises:

an elongate rear lift arm including a front end and a rear end, wherein the rear end of the rear lift arm is pivotally attached to the chassis at a transverse lift arm pivot axis;

a lift actuator attached between the elongate rear lift arm and the chassis, wherein the lift actuator is adapted to extend or retract to pivot the elongate rear lift arm relative to the chassis;

an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm; and

a controller adapted to extend or retract the extension actuator in concert with movement of the lift actuator to maintain movement of the connection point along a predetermined path.

8. The compact utility loader of claim 7, wherein extension actuator extends when the lift actuator extends to maintain movement of the connection point along a direction normal to the ground surface.

9. The compact utility loader of claim 7, wherein extension actuator retracts when the lift actuator retracts to maintain movement of the connection point along a direction normal to the ground surface.

10. The compact utility loader of claim 7, wherein extension actuator extends when the lift actuator retracts to maintain movement of the connection point along a direction normal to the ground surface.

11. The compact utility loader of claim 7, wherein extension actuator retracts when the lift actuator extends to maintain movement of the connection point along a direction normal to the ground surface.

12. The compact utility loader of claim 7, wherein the extension actuator extends prior to maintaining movement of the connection point along the predetermined path.

13. The compact utility loader of claim 7, wherein the lift arm assembly is configurable in a synchronized mode and a manual mode, wherein the controller is adapted to move each of the lift actuator and the extension actuator such that the connection point maintains movement along the predetermined path when in the synchronized mode.

14. The compact utility loader of claim 7, wherein the prime mover is positioned on the chassis at a location lateral to the lift arm assembly.

15. The compact utility loader of claim 7, wherein the controller is adapted to restrict operator extension of the extension actuator.

16. A method of moving a lift arm assembly of a compact utility loader, the method comprising:

providing the compact utility loader, wherein the compact utility loader comprises:

a chassis carrying a prime mover;

a control console located at or near a rear end of the chassis, the control console carrying controls adapted to be manipulated by an operator either: standing on a platform mounted near the rear end of the chassis; or walking behind the chassis; and

an extension actuator adapted to extend or retract the front lift arm relative to the rear lift arm;

extending or retracting the lift actuator to move the elongate rear lift arm relative to the chassis; and

automatically extending or retracting the extension actuator in concert with extending or retracting the lift actuator to maintain the connection point in a vertical plane.

17. The method of claim 16, further comprising positioning the connection point in the vertical plane prior to automatically extending or retracting the lift actuator and the extension actuator.

18. The method of claim 17, wherein positioning the connection point in the vertical plane comprises manually extending or retracting one or both of the lift actuator and the extension actuator.

19. The method of claim 17, further comprising positioning the lift arm assembly along a generally horizontal plane relative to the ground surface prior to automatically extending or retracting the lift actuator and the extension actuator.

20. The method of claim 16, further comprising restricting operator extension of the extension actuator.