Patent Application
20200263386
The present application relates generally, but not by way of limitation, to lift arms for loaders. More particularly, but not by way of limitation, the present application relates to lift arms having cross members and pin couplings that can be used in underground wheel loaders.
Wheel loaders, track loaders, and other loading machines are equipped with buckets for the purposes of digging, loading, and transporting different types materials. An underground loader, also known as a load, haul, dump (LHD) machine, is adapted to perform these functions at underground mining sites, which can present smaller, more confined work spaces than surface-level operations. Despite the varying logistical difficulties presented at different mining sites, common to most is that materials in a loose state such as ore, rock and gravel must be moved around and often among different machines for transport and processing. One typical loader application at mine sites is the loading of blasted rock such as ore or overburden into a truck for disposal or transport to a processing site, or delivery of ore directly to a crusher.
As suggested above, underground access is typically relatively limited, often resulting in narrow passageways, low clearances, and other difficulties. While loaders for surface mining and underground loaders share many features, underground loaders and related equipment are often purpose-built to meet the logistical challenges of underground excavation, typically having heavy planetary axles, four-wheel drive, and articulated steering to maximize maneuverability while having a narrower, longer, and lower profile in order to fit into tight access points. These adaptations extend not only to the body of underground loaders but also to its operational features such as the bucket and lift arms coupling the bucket to the body.
Publication No. US 2015/0345103A1 to Daiberl, entitled “Linkage Assembly For Machine,” and Publication No. US 2018/0087236 A1 to Marek et al., entitled “Implement System With Bucket Having Torsional Support, And Machine having Same,” disclose lift arms for loaders.
A lift arm for a loader can comprise a pivot end section extending along a first axis and including a first pin hole defining an origin at the intersection of a vertical x-axis and a horizontal y-axis, a bucket end section extending along a second axis and including a second pin hole located a first distance away from the origin on the y-axis, and a hump section connecting the pivot end section and the bucket end section, wherein the hump section can comprise a lifting cylinder coupler section including a third pin hole located a second distance away from the y-axis that is approximately one-third of the first distance, and a torque tube coupling section.
A lift arm assembly for a loader can comprise a first lift arm, a second lift arm, and a torque tube structure connecting the first lift arm and the second lift arm, wherein the torque tube structure can comprise a first lift arm coupler connected to the first arm and comprising a first pocket for receiving a first lift cylinder coupler, a second lift arm coupler connected to the second arm and comprising a second pocket for receiving a second lift cylinder coupler, and a torque tube extending from the first lift arm coupler to the second lift arm coupler.
As shown in
Lift cylinders 28A and 28B can be extended and retracted to rotate lift arms 12A and 12B at pivot point 32. Specifically, lift cylinders 28A and 28B can be extended to raise lift arms 12A and 12B and can be retracted to lower lift arms 12A and 12B. Tilt cylinder 40 can be actuated to move lever 42 to pivot bucket 26 at pivot point 36, such as for scooping, dumping and hauling operations.
Loader 10 can be configured to perform work associated with a particular industry such as, for example, underground mining, open pit mining, construction etc. For example, loader 10 can be an underground mining loader, as shown in
In order to facilitate operation of loader 10 in subterranean environments, it can be desirable to reduce the height of lift arms 12A and 12B. However, lift arms 12A and 12B must additionally be strong enough to lift bucket 26 and loads located therein, withstand the torque applied thereto by lift cylinders 28A and 28B, and provide lateral or side-to-side stability, in addition to minimizing obstruction to an operator of loader 10 in cab 22. Lift arms 12A and 12B can be provided with cross member 14 that links left and right lift arms 12A and 12B via torque tube 54 (
Frame member 44 can be coupled to frame 18 (
Cross member 14 can comprise couplers 16A and 16B, arm couplers 52A and 52B, torque tube 54, and tilt coupling 56. Lever 42 can comprise side bars 58A and 58B, and connectors 60A and 60B.
Tilt cylinder 40 can comprise piston rod 72 and cylinder housing 74. Lift cylinders 28A and 28B can comprise cylinder housings 77A and 77B, and piston rods 76A and 76B, respectively.
As discussed with reference to
As discussed with reference to
As such, lift arms 12A and 12B are can be coupled to various components of loader 10 in locations that improve the lifting ability of lift arm assembly 11, improve the robustness of lift arm assembly 11, and improve operator visibility. In particular, torque tube 54 and couplers 16A and 16B can be located in close proximity to each other, which is at least partially due to torque tube 54 and couplers 16A and 16B being fabricated from an integral, monolithic component, to lower couplers 16A and 16B relative to pivot point 30 and extend couplers 16A and 16B further away from pivot point 30, thereby improving operator visibility and the amount of torque that can be generated at pivot point 30 by lift cylinders 28A and 28B, respectively.
With reference to
As such, bucket 26 can be tilted by actuation of tilt cylinder 40. For example, piston rod 72 can be extended from cylinder housing 74 (into the position shown in
Pivot points 62, 64, 66, 68 and 70 can comprise coupling locations for pivotably connecting tilt mechanism 38 to various components, such as through the use of pinned couplings. Tilt mechanism 38 is shown and described as being coupled via pins, but can be coupled by any suitable coupling means, such as couplers, pins, latches or any other mechanism generally known in the art. As described herein, pivot points 62, 64, 66, 68 and 70 can comprise holes or sockets located within the various components through which a pin can be extended to provide a rotatable or pivotable coupling.
With reference to
Pivot points 30, 32, 34 and 36 can comprise coupling locations for pivotably connecting lift arms 12A and 12B to various components, such as through the use of pinned couplings. Lift arms 12A and 12B are shown and described as being coupled via pins, but can be coupled by any suitable coupling means, such as couplers, pins, latches or any other mechanism generally known in the art. As described herein, pivot points 30, 32, 34 and 36 can comprise holes or sockets located within the various components through which a pin can be extended to provide a rotatable or pivotable coupling.
As can be seen in
Lift arm 12A can comprise main body 92A including pivot end section 94A, hump section 96A and bucket end section 98A. Pivot end section 94A can include eyelet 78A, hump section 96A can include pocket 100A, and aperture 86A, and bucket end section 98A can comprise eyelet 88A. Lift arm 12B can comprise main body 92B including pivot end section 94B, hump section 96B and bucket end section 98B. Pivot end section 94B can include eyelet 78B, hump section 96B can include pocket 100B, and aperture 86B, and bucket end section 98B can comprise eyelet 88B.
Cross member 14 can comprise couplers 16A and 16B, arm couplers 52A and 52B, torque tube 54, tilt coupling 56 and eyelet 84. Coupler 16A can comprise sidewall 102A and 104A, between which is formed pocket 106A. Coupler 16B can comprise sidewall 102B and 104B, between which is formed pocket 106B.
Main body 92A can comprise a planar member into which eyelets 78A and 88A aperture 86A and pocket 100A can be formed. Hump section 96A can comprise a C-shaped or crescent-shaped body that forms pocket 100A. Pockets 100A can be shaped to receive arm coupler 52A. A such, main body 92A can be formed from a plate of material and cut to the desired shaped. Eyelets 78A and 88A can be reinforced such as with tubular sections. Main body 92B can be configured in a similar fashion as main body 92A.
Cross member 14 can be a unitary component having an H-shaped configuration, with arm couplers 52A and 52B forming legs of the H and torque tube 54 forming the connecting body. Torque tube 54 can comprise a walled body having an internal passage extending therethrough. Torque tube 54 can have a teardrop cross-sectional shape to, for example, resist twisting. In general a teardrop cross-sectional shaped as used herein can comprise oblong shapes having curved ends wherein one end has a larger radius of curvature than the other. Torque tube 54 can also have a “bean-shaped” cross-sectional profiles. Teardrop and bean shaped torque tubes can be resistant to twisting and also provide adequate strength to connect lift arms 12A and 12B. The wall of torque tube 54 can connect directly to arm couplers 52A and 52B at torque tube perimeter portions of 52A and 52B. Tilt coupling 56 can extend from torque tube 54 and coupled to eyelet 84. Couplers 16A and 16B can comprise sidewalls 102A and 104A and 102B and 104B, respectively. Walls can be spaced so that eyelet 80A and 80B can be disposed therein.
Cross member 14 can comprise a monolithic component wherein arm couplers 52A and 52B, torque tube 54, tilt coupling 56, eyelet 84 and sidewalls 102A and 104A are integrally connected. In an example, cross member 14 can be formed as a cast component that is machined to size and include features such as apertures 91A.
Arm couplers 52A and 52B can be coupled to pockets 100A and 100B, respectively, such via a welding process. As such, torque tube 54 can provide a rigid lateral or side-to-side coupling for lift arms 12A and 12B. Welding can improve life of torque tube 54, such as versus torque tubes that were previously welded directly to lift arms, such as by locating the weld seam away from stress points on torque tube 54. Additionally, couplers 16A and 16B can be positioned close to torque tube 54 due to, for example, the integral or monolithic construction of cross member 14. In an example, portion of the wall of torque tube 54 can form portions of couplers 16A and 16B. Also, the integral or monolith construction of cross member 14 permits sidewalls 102A-104B to be strong enough to support coupling to lift cylinders 28A and 28B at an eyelet configuration, rather than with a clevis configuration where a single hole would be provided in a lift arm and a U-shaped coupler on a hydraulic piston shaft having two holes therein would be coupled to the outside of the lift arm. Couplers 16A and 16B facilitate the use of eyelets 80A and 80B, which allow the axis of pivot point 32 to be brought closer to cylinder housing 74 when piston rod 72 is fully retracted, as compared to a clevis embodiment. In other words, use of eyelets 80A and 80B reduce the amount of “dead length” within housing 77A and 77B, which is particularly important for incorporating in-cylinder sensing. As such, the overall length of lift cylinders 28A and 28B can be shortened, which facilitates reducing the height of hump sections 96A and 96B relative to pivot point 30 thereby improving operator visibility.
Pivot end section 94A and bucket end section 98A provide length to lift arm 12A in order to distance pivot point 36 away from pivot point 30. As such, lift arm 12A can provide clearance of moving bucket 26 out beyond the front end of loader 10 and front traction devices 20.
Pivot point 34 can be located at a location suitable for providing side bars 58A and 58B suitable leverage for tilting bucket 26. For example, it can be desirable for pivot point 34 to be close to the X-axis to improve operator visibility, but above pivot point 36 to allow tilt cylinder 40 to apply torque to pivot point 36.
Pivot point 32 can be located close to the X-axis to reduce the height of hump section 96A, thereby improving operator visibility. Furthermore, pivot point 32 can be located away from pivot point 30 to assist lift cylinders 28A and 28B in generating adequate torque at pivot point 30. In order to extend the distance that pivot point 32 is located from pivot point 30, pivot point 32 can be incorporated into cross member 14. Cross member 14 can be fabricated as a single-piece component separate from lift arms 12A and 12B. As such, pivot point 32 can be located in close proximity to torque tube 54 without compromising integrity of torque tube 54 or couplers 16A and 16B.
Pivot point 30 can be located at the origin of the coordinate system, at point (0.0) on the X-axis and Y-axis. Pivot point 36 can be located on the X-axis some distance from the Y-axis, at point (P1,0) on the X-axis and Y-axis. Pivot point 32 can be located some distances from the X-axis and the Y-axis at point (P2, P3) on the X-axis and Y-axis. Pivot point 34 can be located some distances from the X-axis and the Y-axis at point (P4, P5) on the X-axis and Y-axis.
In an example, pivot point 32 can be located approximately one-third of the distance between pivot points 30 and 36 from pivot point 30. In an example, pivot point 34 can be located approximately two-thirds of the distance between pivot points 30 and 36 from pivot point 30.
In an example, coordinates P2 and P3 for pivot point 32 can be approximately 1.142 and 0.241 units of measure, respectively from the origin. In configurations where through bore 89 is presented in combination with omitting pocket 16A, such as is shown in
In the present application, a unit of measure can be a meter. The present inventors have found that the specific locations for the various pivot points described herein achieve the benefits for the specific embodiment described herein. Depending on specific embodiments and design needs, the exact locations of the pivot points described herein, such as coordinates P1-P5, can be moved to meet specific design needs. The present inventors have found that points described herein, such as coordinates P1-P5, can be moved within a tolerance radius of 0.14 units of measure, e.g. 140 mm, in order to maintain desired lifting capabilities, turn radii, stress limitations, safety considerations and the like. More particularly, coordinates P1-P5, can be moved within a tolerance radius of 0.1 units of measure, e.g. 100 mm, in order to maintain desired lifting capabilities, turn radii, stress limitations, safety considerations and the like. Likewise, the assemblies and components described herein, such as lift arms 12A and 12B, can be scaled-up or scaled down to different sizes while maintaining the same proportions to achieve desirable performance characteristics.
In an example, D1′ and D2′ can comprise 0.977 and 0.591 units of measure relative to the X′-axis and the Y′-axis. For comparison, in such example, D1 and D2 can comprise 0.834 and 0.780 units of measure relative to the X-axis and the Y-axis, e.g., D1 and D2 can comprise 0.834 and 0.780 units of measure.
The present disclosure describes various systems, assemblies, devices and methods for constructing and operating lift arm assemblies, such as for use with loaders including underground wheel loaders.
The shape and dimensions of lift arms 12A and 12B can be determined to allow for placement of pivot point 32 for lift cylinders 28A and 28B. In particular, the distance of pivot point 32 from pivot point 30 can be increased, as compared to lift arms not having couplers 16A and 16B integrated into cross member 14 with an integrated torque tube 54. Such placement additionally reduces the height of peak 108 to increase operator visibility while at the same time providing increased torsional rigidity and improved strength with the capability to withstand higher stress, e.g., greater breakout force.
Incorporation of torque tube 54 and couplers 16A and 16B into cross member 14 additionally facilitates the use of in-cylinder sensing by providing additional length in the hydraulic cylinder housing to reduce “dead length, thereby freeing space for sensors, such as electronic position sensors for piston rods 76A and 76B. In other configurations, in-cylinder sensors can be replaced with external sensors, such as rotary sensors, to, among other things, achieve more beneficial breakout forces and to facilitate use of clevis couplers on lift cylinders rather than lift cylinders using eyelets.
