CARGO RESTRAINT GRIPPING SYSTEM

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The research and development related to this invention was funded at least in part by the U.S. Department of Defense, Office of Naval Research, Grants Nos. N00014-03-M0276 and N00014-04-C-0345.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority of prior U.S. Provisional application S.N.

60/652,794 filed on February 14, 2005, which application is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to a quick-release restraint system for a Landing Craft Air Cushion (LCAC). The system advantageously reduces the time required to secure and release cargo on an LCAC without incurringa weight penalty over existing systems.

BACKGROUND OF THE INVENTION

Those of ordinary skill in the art will appreciate that a Landing Craft Air Cushion (LCAC) is a high-speed, over-the-beach, fully amphibious landing craft capable of carrying a 60-75 ton payload. Capable of operating from existing and planned well deck ships, LCACs are used to transport weapons systems, equipment, cargo and personnel from ship to shore and across the beach. The advantages of air-cushion landing craft are numerous and widely recognized. LCACs can carry heavy payloads, such as an M-1 tank, at high speeds. Their payload and speed

mean more forces reach the shore in a shorter time, with shorter intervals between trips.

An LCAC is capable of carrying a 60 ton payload (up to 75 tons in an overload condition) at speeds over 40 knots. Fuel capacity is 5000 gallons. The LCAC uses an average of 1000 gallons per hour. Maneuvering considerations include requiring 500 yards or more to stop and 2000 yards or more turning radius. An LCAC, like all "hovercraft," rides on a cushion of air. The air is supplied to the cushion by four centrifugal fans driven by the craft's gas turbine engines. The air is enclosed by a flexible skirt system manufactured of rubberized canvas. Unlike the Surface Effect Ship (SES), no portion of the LCAC hull structure penetrates the water surface; the entire hull rides approximately four feet above the surface.

Cargo restraint is one of the "core" technologies for the movement of all logistics. Shifting cargo in any sea-borne vehicle, such as an LCAC, threatens both the vessel and its crew and cargo. Consequently, a great deal of effort has gone into developing technologies for securing cargo to ensure that the cargo will not move during even the most violent vessel movement. Unfortunately, such rigging, designed to ensure security, often does so at the expense of mounting and dismounting speed. While for most loading and unloading efforts in the commercial world, the time needed to secure and release cargo has impact only on profits, there is a completely different impact in the context of military applications. For example, releasing cargo on a beachhead while under fire exposes the crew, the vessel as well as the cargo to significant risk. Every second counts and every second that an asset sits on the deck of a vessel immobile increases the probability that an enemy might target the vessel to destroy it and the cargo. Current systems are designed so

that each restraint must be administered by a crewmember. During the time a crew is releasing the cargo, they are open to enemy fire and are in harm's way.

SUMMARY OF THE INVENTION

In view of the foregoing, the present invention is directed to a cargo restraint gripping system which minimizes the time and personnel required to load and grip cargo, either vehicular or palletized, on a LCAC, without a significant weight penalty. In one embodiment, the major components of the LCAC Cargo Restraint Gripping System include mechanical components, including a powered turnbuckle and a quick-release hook, as well as a control system, referred to as a "Smart System," incorporating a grip communication and controller (GCCM), which is a communication and control mechanism on the grip including ID, security, etc... and a crew communication and controller (CMC), which is a control device carried by the crew including a display, communication, and control algorithms issues.

In one embodiment, the cargo restraint gripping system in accordance with the present invention includes a sensor package (SP) including sensors for load, health, and position change, as well as an energy package (EP) including a power source and a charger. The energy package provides power to, among other components, a motor/gearing assembly (MG) and corresponding motor/gear train assembly.

In accordance with one embodiment of the invention, the system advantageously reduces the time required to secure and release cargo on the LCAC. Moreover, the System is lighter weight than existing systems.

The system has preferably has a lifting capacity on the order of 35,000 lbs., and is of a robust design which can be upfeatured or downfeatured as necessary for a given application.

In accordance with another aspect, the system has an improved quick- attach/release feature and can be lifted, positioned, and operated by a single crewman.

Preferably, the system incorporates manual backup mechanism and an automatic release mechanism. Further, the system is of robust construction such that it will operate in the extreme LCAC environmental conditions of temperature extremes, humidity extremes, salt water, dirt and sand. The system can be used with cargo restrained with either chains or cables or both.

In accordance with still another aspect of the invention, a system comprising a plurality of individual cargo restraint gripping systems can be controlled by a single crewmember using a radio-frequency remote monitoring and control unit. In one embodiment, the radio-frequency communication can extend over a range of up to 300 feet, and may utilize, for example, known radio-frequency identification (RFID) technologies. The remote communications may be encrypted.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and aspects of the present invention will be best appreciated by reference to a detailed description of specific embodiments of the invention, when read in conjunction with the accompanying drawings, wherein: Figure 1 is a perspective view of a cargo restraint gripping system system in accordance with one embodiment of the invention;

Figure 1a is a perspective view of a crew monitor/controller utilized in connection with the gripping system of Figure 1 ;

Figure 2 is an isometric drawing of a powered tumbuckle assembly in the embodiment of Figure 1 ;

Figure 3 is an exploded view of the powered turnbuckle assembly of Figure 2;

Figure 4 is a view of the powered turnbuckle assembly of Figure 2 shown in disassembled condition;

Figure 5 is an isometric drawing of the assembly of Figure 2 with a power unit added thereto;

Figure 6 is an partially cut-away perspective view of a quick release hook assembly in accordance with one embodiment of the invention;

Figure 7 is a view of the quick release hook assembly with its components disassembled; and Figure 8 is a system diagram of the components of a smart system in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

In the disclosure that follows, in the interest of clarity, not all features of actual implementations are described. It will of course be appreciated that in the development of any such actual implementation, as in any such project, numerous engineering and technical decisions must be made to achieve the developers' specific goals and subgoals (e.g., compliance with system and technical constraints), which will vary from one implementation to another. Moreover, attention will necessarily be paid to proper engineering and programming practices for the environment in question. It will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the relevant fields.

MECHANICAL COMPONENTS

Powered Turnbuckle

Referring to the Figures , there is shown a LCAC cargo restraint gripping system 10 in accordance with one embodiment of the invention _* As shown in Figure

1 , system 10 comprises a powered turnbuckle mechanism 12 that is used to create a self-tightening and self-releasing gripping system. Energy/time profiles militate against a powered, "cam-over" mechanism for self-tightening. In accordance with one aspect of the invention, the system uses an arrangement of high strength bevel gears shown in Figure 4. In particular, system 10 employs a chain receiver bevel drive gear 14 and a claw screw bevel drive gear 16 which rotate a chain receiver 18 and a claw receiver 20, as well as a chain screw 22 and a claw screw 24. Chain receiver bevel drive gear 14 and claw screw bevel drive gear 16 each revolve around

a forged central axle 26. The bevel gears 14 and 16 are attached to the internally threaded receiver tubes, which provide the pull on a hook 28. The receiver tubes, attached to the bevel gears, are driven by a driver bevel gear 30, which is permanently attached to the central axle. When the driver bevel gear 30 is rotated, the bevel gears 14 and 16 on the receiver tubes rotate the same direction. If the driver bevel 20 is rotated counterclockwise, both receiver bevels 14 and 16 rotate clockwise. The right handed threaded hook bolt 22 would be drawn into the receiver tubes and the chain tensioned. If the driver bevel 30 is rotated clockwise, the chain would be loosened. It is estimated that an electric motor or impact wrench of current design with peak torque of 250 ft-lbs would easily spin the gear even under severe loads.

In a highly "upfeatured" embodiment of the invention (i.e., one incorporating certain elements which might not be necessary or appropriate in all cases, the turnbuckle components include: a chain hook 28, a chain screw 22, a chain receiver 18, a chain receiver bevel drive gear 14, a drive bevel gear 30 and emergency V2 drive recepticle 32 (see Figure 3), an alignment pin 26, a claw screw bevel drive gear 16, a main housing 34, a battery 36 (see Figure 8), a motor 38 (see Figure 8) and electronic housing 40 (see Figure 8), a claw screw 24 (see Figure 4), a claw receiver 20 (see Figure 4), and a claw and hook assembly 40. The components are preferably of forged steel construction and sealed to the environment. The assembly 10 is insensitive to extreme heat or cold. A quick manual override of the motor- powered system is provided by means of emergency drive receptacle 32.

Quick Release Hook

In accordance with an important aspect of the invention, the quick release hook 40 is designed to hold when engaged, even before the turnbuckle has begun

winding, when the grip is in its most extended position, then to lock in such a way that load shifting will not cause the release to disengage while tightening, and yet release when instructed by the Crew Monitor Controller (CMC), as will be hereinafter described in further detail. Finally, in the case of a motor or communication failure, it is quickly releasable through a simple direct intervention by the crew through manual application of force on release tab 43.

With reference especially to Figures 6 and 7, the quick release hook components include a claw receiver 20, a hook actuator spring 42 (see Figure 6), a detent 47 and spring 46 assembly, and a hook 48. The components are of forged steel construction and sealed to the environment. The assembly is insensitive to extreme heat or cold.

SMART SYSTEM

Grip Controller Communication Module

In one embodiment, the function of the GCCM 54 is to monitor and interpret the signals coming from the load sensors, motor and battery, internal to the grip 10, as well as Crew Monitor Controller, as will be described hereinafter in further detail.

The GCCM 54 within housing 40 sends data from the grip 10 to the CMC 50, including such information as battery strength, the load on the grip, a unique identification of the grip, and whether the grip has released and dropped to the

ground.

Further, the GCCM 54 can receive data from the CMC 50and act on it in order to perform certain functions, such as to order the load to be released, order the tension on the load to be increased or loosened in transit, and, after release, to order grip 10 to extend to a fully released position.

Crew Monitor/Controller

The Crew Monitor/Controller (CMC) 50, shown in Figure 1a, functions as the brains behind the gripping system 10. In one embodiment, CMC 50 is a hand-held transceiver with a keypad, barcode scanner, LCD display, which performs various functions, following functions:

In one embodiment, CMC 50 monitors and stores information coming from individual grips. Such information may include, without limitation, a unique identifier (ID) of each grip; the condition of each grip; remaining battery life; the current load on the grip; and certain error conditions exhibited by the grip. With continued reference to Figure 1a, a display 52 is preferably provided:

The handheld CMC 50 preferably includes a mapping and display capability so that a graphical representation of the deck of an LCAC can be shown to identify which grip has loosened and which has dropped to the deck.

CMC 50 also preferably is capable of sending a release signal to each grip, and can obtain the ID of each grip when it is installed so that it can be identified and located. CMC 50 further preferably communicates with the ship's stores computer on larger installations so that the locations of the grips and the cargo pallet or vehicle can be found quickly.

Sensor Package Sensors 55 (see Figure 1) are the means by which the smart gripping system

10 perceives its environment. Included are sensors for detecting that the load has been placed on the sensor during the winding or tightening process or by shift of the load during movement. In addition, it is important to know with certainty that the grip 10 has fully disengaged from the load when it is time for the vehicle to disembark from its carrier. It would be dangerous for the crew to have to run around the deck

searching for a grip that was supposed to be fully released, but for some reason has not dropped to the deck. Accordingly, sensor package 55 preferably indicates dropping to the deck and full disengagement. In addition, for the fastest redeployment, the grip must be in its fully extended mode when the crew is trying to attach the grip to the vehicle. In this way, the grip has the greatest amount of take-up distance when attached to the chain. A sensor tells the system when the turnbuckle is fully extended. Finally, an underway tension adjustment methodology is incorporated. Within the dynamic "envelope" of shipboard operation, a control algorithm balances the need to keep the cargo secure with the control problem of tension "seeking" (i.e. detensioning and over tensioning), battery life, allowable tensioning limits, and so on.

Energy Package

In embodiments which include a motor drive for the turnbuckle, the power source 36 for the motor drive is preferably one selected to strike a balance between power, power density, safety, longevity, cost, and other factors. While battery technology has been moribund for a relatively long time, the latest Lithium battery variations show distinctive advantages in weight, albeit with some safety problems. In one embodiment, a quick charge Aerogel Capacitor is used to power the motor drive.

Motor/Gearing

Again, for embodiments of the invention which incorporate a motor drive 38 for the turnbuckle, the motor is a Quadrant System radially wound, electronically commutated, brushless motor (ECBM). The Quadrant is a variety of ECBM that uses a powdered metal stator to reduce eddy losses, and has a theoretical one pound to

one horsepower output. In accordance with one aspect of the invention, motor drive 38 can be made in a wide variety of aspect ratios (diameter to height) without significant changes in efficiency. In one embodiment, the motor is approximately 400 watts at 18 volts, with a diameter of 70mm and a height of 40mm. Designed into that sized envelope is a 100 to 1 planetary gear, which gives a 300 ft-lb. torque at the shaft. This motor/gearing involves the specification and design of the motor, gear train as well as the electronic control module.

Design Alternatives

From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a cargo restraint gripping system 10 has been disclosed. Although various embodiments of and features for the disclosed system have been described herein, this has been done solely for the purposes of illustrating various features and aspects of the invention and is not intended to be limiting with respect to the scope of claims to the invention now or in the future. Indeed, the versatility and flexibility of the disclosed system and the manners in which it may be implemented is believed to be an important feature of the invention. In accordance with one aspect, the invention comprises a completely flexible gripping system that can be defeatured, or upfeatured to tie down a wide range of cargo, including without limitation, to pallets, aircraft, and so on. At the highest level the invention is a fully automated grip that will self-tighten once attached, maintain its tension while underway, and remotely unlash and drop to the deck with no human interventions at the disembarking port. In a fully-featured implementation, the invention is designed to monitor its own operational status and let its human operators know when it operational intervention is required, such as recharging, maintenance, or relocation.

Key technological components of the invention include a high efficiency, high torque electric drive coupled with an energy storage system in small package. In a preferred embodiment, each grip operates for 50 sorties without recharging and can secure its portion of the load within 45 seconds. This provides an overall time savings in the loading part of the process of 50% to 70% and given that all of the grips will unwind within 30 second on arrival.

Advantageously, disembarking time is only limited by the time it takes to move the vehicles or cargo off of the carrier. The motor power is in the 400- to 500-watt range, and the motor weighs on the order of 14 ounces, and is estimated to have 350 in/lbs, of torque. As noted, the motor drive preferably uses a powdered metal stator and rotor and state-of-the-art magnetic material for a potential of a 1 hp, 1 pound. As a delivered "system" it will weigh approximately 18 lbs for a 15% savings, and will fit within the confines of an LCAC.

In accordance with another important aspect of the invention, in a given implementation a "defeatured" system having fewer than all of the optional functional elements described herein can be provided. At the lowest end, the turnbuckle itself, with an off-the-shelf drill-driver to power it, might be deployed without inclusion of a motor, sensor, or electronics of any type. Such a simple implementation of the invention still offers significant benefits and improvements in lashing/unlashing times as compared with prior art systems.

In another implementation a simple battery-powered tension sensor can be included, such that the guess work can be taken out of tighten-to-load problems. In still another implentationi,

In sum, it is believed that an important aspect of the invention the system is a very powerful turnbuckle tie down that can be as simple or as complex as needed for a given application.

Although specific embodiments and design alternatives have been described herein, it is to be understood that this has been done solely to illustrate various aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications to the embodiments disclosed herein may be made without departing from the spirit and scope of the invention as defined in the appended claims, which follow.