Patent Application
20120298936
Elevator platforms are found on ships, such as aircraft carriers to transfer heavy loads between decks of the ship. A lift assembly located within the hull of the ship mechanically raises and lowers the platform using wire ropes and sheaves. Malfunction of the mechanized components of the platform interferes with activities and operations on-board the ship.
The application discloses a lift assembly configured to raise and lower a platform. Embodiments of the lift assembly have application for an elevator platform of the type described in the Background. As described herein, the lift assembly uses mechanized trolleys to raise and lower the platform. In the embodiments described, the trolleys include a drive portion and a lift portion movable along a track of a support frame or structure. Wire ropes are connected to the lift portion to raise and lower the platform via movement of the lift portion along the track of the support frame or structure. The lift portion is separable from the drive portion and is moved along the track via mechanized movement of the drive portion, for example, via a drive motor.
In an embodiment shown, pairs of trolleys are used to raise and lower the platform. As disclosed lift portions of the pairs of trolleys are connected via tensioned wires or lines to coordinate lift operations for the pairs of trolleys. In the event of failure of the mechanized drives of one trolley, the lift portion of that trolley moves via movement of the lift portion of the companion trolley through the tensioned wires or lines connecting the lift portions of the pair of trolleys. In an embodiment shown, the lift assembly includes four trolleys (or two pairs of trolleys) connected to the platform through wire ropes hitched to the platform. To provide redundancy and to help equalize loads carried by the platform, each trolley includes wire ropes hitched to the platform at multiple hitch points.
This Summary and the Abstract herein are provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary and the Abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that address shortcomings noted in the Background.
As shown, the lift assemblies 102A, 102B include mechanized drive assemblies that move the split trolleys 104A, 104B along a lift stroke to lift the load or platform 106. The trolleys 104A, 104B are connected to the load 106 through wire ropes 110. In the illustrated embodiment, a plurality of wire ropes 110 connect the first trolley 104A to the load 106 at a first or forward hitch point and wire ropes 110 connect the second trolley 104B to the load or platform 106 at a second or aft hitch point of the platform 106 spaced from the first hitch point. The wire ropes 110 connected to the first trolley 104A and the second trolley 104B are wound around sheaves 112A, 112B to guide the wire ropes 110 as the wire ropes 110 are pulled or extended to raise the load or platform 106. In the illustrated embodiment, the first and second hitch points correspond to forward and aft ends of an elevator platform as previously described.
Movement of the trolleys 104A, 104B along the lift stroke raises the load or platform 106. As previously disclosed, the trolleys 104A, 104B are moved along the lift stroke via mechanized drive assemblies. In the embodiment shown, the drive assemblies include a drive motor 116 and a gear assembly or reducer 118. Illustratively the drive motor 116 is an electric, pneumatic and/or hydraulic motor. Output from the drive motor 116 and/or gear assembly 118 is used to rotate a drive mechanism or sprocket 120 which engages a drive chain 122 coupled to the split trolleys 104A, 104B. Drive chains 122 are coupled to the trolleys 104A, 104B and are wound about the drive sprockets 120 so that rotation of the drive sprockets 120 moves the drive chains 122 and trolleys 104A, 104B to raise the load or platform 106. It is noted that the pitch diameter of the sprocket 120 should be as small as possible to reduce the amount of torque needed for operation, and hence, the torque capability of the gear reducer 118.
As shown in the illustrated embodiment, a chain or wire rope 124 connects an end of the drive chain 122 to the trolleys 104A, 104B. The chain 124 is wound about sheave 125 to form a continuous drive loop in cooperation with the drive chain 122. In the illustrated embodiment, chain 124 is a lighter weight chain than drive chain 122. In another embodiment a cable or other flexible member connects to the end of the drive chain 122 and to trolleys 104A, 104B to form the continuous drive loop.
In the embodiment shown, the drive assembly includes a brake 126 to hold the load in a raised position. Brake 126 operates to inhibit operation of the drive motor 116 or gear assembly 118 to brake or prohibit movement of the trolleys 104A, 104B. Illustratively, the brake 126 can include a caliper, drum or disc brake arrangement and application is not limited to a particular brake embodiment or a brake operable through the drive assembly as can be appreciated by those skilled in the art. In an illustrated embodiment, brakes 126 are configured to operate in a fail safe manner (for example, where the calipers are held back in a non-braking position by a hydraulic, pneumatic or electrical device and are moved to a braking position by a spring) so as to actively hold the platform 106 in a stable position when the power to the motors 116 is off or lost.
In the embodiment shown, the split trolleys 104A, 104B include a drive portion 130 and a lift portion 132. The trolley drive portion 130 is connected to the drive chain 122 and the wire ropes 110 are connected to the lift portion 132. Movement of the drive chain 122 moves the drive portion 130 of the trolleys 104A, 104B along the lift stroke. The lift portion 132 is in front of the drive portion 130 (with respect to movement during the lift stroke) so that movement of the drive portion 130 engages the lift portion 132 and pushes the lift portion 132 along the lift stroke. Movement of the lift portion 132 of the trolley pulls the wire ropes 110 in the direction of the lift stroke to raise the load or platform 106.
In the illustrated embodiment, the lift assembly 102A moves the split trolley 104A in a first or aft direction as illustrated by arrow 140 to raise a forward portion of the load 106 and the lift assembly 102B moves the split trolley 104B in a second or forward direction opposite to the first direction as illustrated by arrow 142 to raise an aft portion of the load or platform 106. In the illustrated embodiment lift assemblies 102A, 102B and trolleys 104A, 104B form a pair of trolleys to provide a compact design. In the illustrated embodiment, the trolleys 104A and 104B are arranged in a stacked manner so that the first or forward lift assembly 104A is elevated above the second or aft lift assembly 102B although application is not limited to the particular stacked arrangement shown. For example the aft lift assembly 104B could be elevated above the forward lift assembly 102A in another embodiment.
In the embodiment shown, lift portions 132 of trolleys 104A, 104B are connected through one or more tensioned trolley lines to interconnect the trolleys 104A, 104B to provide synchronized movement of the trolleys 104A, 104B in the event of failure the drive components or mechanisms of one of the lift assemblies 102A, 102B. In particular, in the embodiment shown, the one or more tensioned trolley lines includes a first trolley line 144A coupled to a front end of the lift portion 132 of trolley 104A and a back end of the lift portion 132 of trolley 104B and a second trolley line 144B coupled to the front end of lift portion 132 of trolley 104B and a back end of lift portion 132 trolley 104A to form a continuous loop of trolley lines 144A and 144B.
Thus, as shown, trolley 104A is interconnected to trolley 104B through line 144A and trolley 104B is interconnected to back trolley 104A through line 144B so that trolley 104A and trolley 104B synchronously move along the lift stroke. As shown, the first and second trolley lines 144A, 144B are wound about sheaves or pulleys 148 to form the continuous loop interconnecting the lift portions 132 of the trolleys 104A, 104B
As comparatively illustrated in
Sheaves 112A and 112B located on the aircraft carrier at various locations guide the wire ropes 110 between trolleys 104A-104D and the platform 106. Guide rails 152 are provided along an edge of the carrier or ship to guide the inboard side of the platform 106 hitched to the wire ropes 110 of the lift assembly at hitch points 150C and 150D. As shown, an outboard edge of the platform 106 hitched to the wire ropes 110 of the lift assembly at hitch points 150A and 150B is unguided, and is supported by the wire ropes 110 to raise and lower the platform 106. Operation of the trolleys 104A-104D raises the platform 106 to the flight or other deck of the ship or aircraft carrier. In the embodiment illustrated, the trolleys 104A-104D move along the lift stroke to raise the platform until the platform 106 contacts hard stops 153 proximate to the flight deck or other location.
In operation, the loads carried by the wire ropes 110 for each of the hitch points 150A-150D are not all the same. For example in an illustrated embodiment, wire rope loads for the outboard hitch points 150A and 150B are typically greater than the loads carried by the wire ropes 110 for inboard hitch points 150C and 150D. In order to balance the loads carried by each of the trolleys 104A-104D, each trolley 104A-104D is connected to one inboard hitch point 150C or 150D as well as to one outboard hitch point 150A or 150B.
In the embodiment illustrated, there are four wire ropes 110 connected to each hitch point 150A-150D and four wire ropes 110 connected to each trolley 104A-104D. For each hitch point 150A-150D, two wire ropes are connected to a first trolley, while the remaining two wire ropes are connected to another trolley. In the embodiment shown; wires 110 from trolley 104A are connected to hitch points 150A and 150B; wires from trolley 104B are connected to hitch points 150B and 150D; wires 110 from trolley 104C are connected to hitch points 150C and 150A; and wires from trolley 104D are connected to hitch points 150D and 150B. It should be appreciated that application is limited to the embodiments described where two wire ropes are connected to each trolley 104A-104D and corresponding hitch points 150A-150D and that any number of wire ropes 110 or arrangements can be used to connect trolleys 104A-104D to hitch points 150A-150D on the platform 160.
In the embodiment shown, each trolley 104A-104D is connected to two hitch points that are on the same aft end or forward end of the ship or platform 106. In an alternative embodiment, each trolley 104A-104D can be connected to inboard and outboard hitch points that are diagonally opposed to each other. Other hitching arrangements can be employed as will be appreciated by those skilled in the art. It should be noted that not all the components of
As shown in
As shown in
As shown, the threaded fittings 172 are connected to the connector rods 174 through studs 180. As shown, the studs 180 are generally rectangular shaped and are supported between legs of “U” shaped brackets on the body of the lift portion 132 to restrict rotation of the wire ropes 110. As illustrated in
As shown in
As previously described, trolley lines 144A, 144B are connected to the forward and rear ends of the lift portions 132 to interconnect pairs of trolleys 104A-104B and 104C-104D. In the illustrated embodiment, the trolley lines 144A, 144B includes two tensioned wires 194A, 194B connected to the forward end of the lift portion 132 and two tension wires 194C, 194D connected to the rear end of the lift portion 132 as shown in
As shown, the tensioned wires 194A, 194B, 194C, 194D are connected to upright portions or stanchions on the forward and read ends of the lift portion 132 and are tensioned through springs 198 which supply a bias force to tension the wires 194A, 194B, 194C, 194D connected to the lift portion 132. In the embodiment shown, tension wires 194A, 194B, 192C, 192D are connected to an upper body portion of the lift portion 132 and in illustrative embodiments, additional tension wires can be connected to a lower body portion of the lift portion 132 and thus any number of tension wires can be used to interconnect the trolleys 104A-104B and 104C-104D.
As comparatively shown in
As previously described with respect to
For example, trolley 104A is interconnected to trolley 104B through line 144A (or tensioned wires 194A-194D) so that if drive assembly for trolley 104A is disabled, trolley 104A is pulled along the lift stroke via trolley 104B through trolley line 144A. Trolley 104B is interconnected to trolley 104A through line 144B so that if the drive assembly for trolley 104B is disabled or not operable, trolley 104B is pulled along the lift stroke via trolley 104A through trolley line 144B as described. As shown in
In the embodiments described above where the drive motors 116 comprise electric motors, a significant amount of generated energy is created when the platform 106 is lowered to its lowermost position. Specifically, during lowering, the trolleys 104A-104D move away from each respective drive 116 thereby causing the sprocket 120, gear reducer 118 and motors 116 to rotate in the reverse direction. In this condition, the motors 116 operate as generators. Although operating in this manner is beneficial in that it decreases the speed of which the platform 106 is lowered, the energy generated is quite substantial. In an illustrated embodiment, each motor is operably coupled to a resistive device for heat dissipation. Each of the resistive devices is submerged in an enclosure that can hold water or a flow of water, such as sea water. In view of the corrosive effects of sea water, the resistive devices are formed of a material to work in such an environment. For instance, the resistive devices can be formed of an alloy comprising copper and a nickel. Indeeco of St. Louis, Mo. sells resistive devices suitable for this purpose.
In the event of loss or other problems with the controller 154, manual operation of the drives for trolleys 104A-104D may be available. A manual override circuit would be hard wired to the drives to control the drives 116 to provide command signals. In the event of a controller problem, user selection of the manual override condition would command the drives to run off of a default set of parameters internal to the drives. These parameters would be set to operate the platform 106 in a simplified profile using only the required features important to controlling platform motion. Limit sensing and other non-critical feedback from the system would be ignored to ensure that platform motion can proceed.
Although illustrated and described with a chain and sprocket, the drive mechanism can utilize other flexible members operating in tension such as a belt, cogged belt, rope, wire rope, etc. If necessary, the sprocket can be replaced with a capstan depending on the flexible member used. Furthermore, other types of drive mechanisms besides a drive that pulls on a flexible member operating in tension can also be used. For instance, a linear actuator (electric, hydraulic and/or pneumatic) or screw drive can be used in lift assembly so as to control displacement of each of the trolleys 104A-104D. Although a particular frame structure and upper and lower arrangement or orientation of trolleys is shown, it should be understood however, application is not limited to the particular frame structure, arrangement or number of trolleys shown.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above as has been determined by the courts. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
The present application is based on and claims priority to U.S. provisional patent application Ser. No. 61/479,679 filed Apr. 27, 2011, the content of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61479679 | Apr 2011 | US |
