Patent Application
20170167197
Not applicable
Not applicable
I. Field of the Invention: This invention relates generally to large industrial vehicles and more particularly to a hydraulically ladder for facilitating the ability of a machine operator to reach the operator's station.
II. Discussion of the Prior Art:
Large work vehicles used in earth moving and mining operations and other construction industries, such as dozers, drag lines, excavators, forest machines, mining shovels, trucks for hauling ore, etc, are characterized by having an operator's station or cab that is elevated several feet, sometimes as much as 20 feet, above ground level. Such equipment often includes one or more fixed ladders for allowing a worker to more readily mount the equipment. Power lifts have also been devised, one such lift being shown in the Rivinius Patent 4,217,971. This patent shows a cage or basket at one end of a pair of hydraulically actuated arms that are designed to lift and also rotate the cage carrying the operator from ground level to a location closely adjacent a deck or walkway located immediately below the operator's station. From the deck, the operator may easily enter his or her work station.
Similarly, the Hemisen Patent 3,656,578 shows a work vehicle of the type described on which a ladder is pivotally mounted such that it can be manually swung from a vertical orientation used when mounting the vehicle to a horizontal, stowed position. that forms a guardrail that blocks exit of a worker from. the work station. For a ladder built to withstand the forces and environment encountered in mining and other earth-moving applications, it is somewhat of a challenge to move the ladder from its vertical use position to its horizontal stowed position.
It is therefore an object of this invention to provide a hydraulically actuated ladder capable of deploying the ladder from a stowed position lying underneath and parallel to the vehicle's horizontal deck to a vertical use position where the ladder's bottom end is adjacent the ground and its upper end rests against the outer edge of the vehicle's deck. In the stowed position, it is completely out of the way and not an obstacle to a worker's ability to traverse the deck.
The present invention comprises an apparatus for providing access to an operator's station of a large mobile work vehicle. It includes a frame member adapted to be attached to a side surface of the work vehicle at a location immediately below the operator's work station, where the frame member supports a horizontally disposed deck surface. Located below the deck surface and affixed to the frame is a support structure to which a yoke member is pivotally joined to allow the yoke member to swing about a vertical axis. A ladder having a pair of stringers maintained in parallel, spaced relation by a plurality of spaced-apart tread members has first ends of the pair of stringers pivotally joined to the yoke member for rotation about a horizontal axis. A mechanical actuator is operatively coupled between one of the pair of stringers and the yoke. A linkage having first and second ends is installed with the first end being pivotally affixed to the support structure for rotation about a vertical axis and a second end of the linkage coupled to the other of the pair of stringers, i.e., the stringer that does not have the mechanical actuator coupled to it. An electric motor is operatively coupled to the mechanical actuator whereby actuation of the electric motor moves the mechanical actuator in a first direction to displace the ladder from a stowed position immediately below and parallel to the deck surface to a use position where the ladder extends from adjacent the ground to the deck surface. The above-mentioned linkage is preferably a turnbuckle whose length can be readily adjusted so as to control the locus of travel of the ladder in moving between its stowed position and its use position.
The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description of a preferred embodiment, especially when considered in conjunction with the accompanying drawings in which like numerals in the several views refer to corresponding parts.
This description of the preferred embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom” as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc,) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “join” and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressively described otherwise.
Referring first to
The powered ladder assembly 12 is seen to comprise a ladder 20 having a pair of stringers 22 and 24 maintained in parallel, spaced relation by a plurality of spaced-apart tread members 26. Hand railings, as at 28, are affixed to the stringers to provide for safer ascent and descent of the operator to and from the work vehicle.
Referring momentarily to
to comprise an elongated vertical portion comprising first and second horizontally extending steel bars or tubes 30 and 32 maintained in parallel, spaced relation by a plurality of vertical struts 34. Welded to the elongated horizontal bar or tube 30 is a platform or deck 18 that is cantilevered outwardly by horizontal struts 36. Welded to the outer ends of the horizontal struts 36 is a front rail 38. As previously mentioned, affixed to the upper surfaces of the rails 30 and 38 and further supported by the horizontal struts 36 is one or more sheets of steel that preferably have a rough surface that provides a walkway for an operator. Expanded metal sheets (not shown) are preferable in that they permit dirt and debris that may be carried by the operator's shoes to fall back down to the ground.
Referring next to
As shown in
As seen in.
Assuming that the ladder is in its use position, as shown in
In deploying the ladder from its stowed disposition to its use position, just the opposite action occurs. As the piston rod 72 extends out from the cylinder barrel 76, the force exerted on the ladder by the piston, along with the resulting force acting on the turnbuckle linkage, results in movement of the ladder from its stowed disposition (shown in
This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use such specialized components as are required. However, it is to be understood that the invention can be carried out by specifically different equipment and devices. Also, various modifications, both as to the equipment and operating procedures, can be accomplished without departing from the scope of the invention itself.
