Magnetically actuated personnel restraint system

Abstract

A magnetically actuated cargo restraint system for a vehicle includes a rotatable reel and a flexible tether. The tether has a first end coupled to the reel and a second end capable of being coupled to a cargo item. The tether is windable around the reel, and is movable in both a winding direction and an unwinding direction. A magnetic drag device includes a magnet containing member having a plurality of magnets thereon, and a conductor member. The magnet containing member and magnetic conductor are moveable relative to each other, and one of the magnetic containing member and conductor member is capable of being fixedly coupled to the reel for movement with the reel. Movement of a cargo item attached to the tether in a direction that causes the tether to move in an unwinding direction on the reel causes relative movement between the magnet containing member and conductor which generates magnetic eddy currents between the magnet containing member and the conductor to thereby create a retarding torque on the reel that resists, but does not prevent, movement of the tether in an unwinding direction on the reel to thereby retard movement of the cargo item.

1 . A magnetically actuated cargo restraint system for a vehicle comprising: 
 (a) a rotatable reel,    (b) a flexible tether having a first end coupled to the reel and a second end capable of being coupled to a cargo item, the tether being windable around the reel, and movable in both a winding direction and an unwinding direction,    (c) a magnetic drag device including a magnet containing member having a plurality of magnets thereon, and a conductor member, the magnet containing member and conductor member being moveable with respect to each other, and one of the magnetic containing member and conductor member being capable of being fixedly coupled to the reel for movement with the reel,    wherein movement of a cargo item attached to the tether in a direction that causes the tether to move in an unwinding direction on the reel causes relative movement between the magnet-containing member and the conductor which generates electrical eddy currents which give rise to a retarding torque on the reel that resists, but does not prevent, movement of the tether in an unwinding direction on the reel to thereby retard movement of the cargo item.    
   
   
       2 . The restraint system of  claim 1  wherein, the cargo item comprises a human being and the vehicle comprising an aircraft, and the tether comprises a belt like webbing type tether, and the retarded movement of the cargo item comprises an attenuation type retarded movement.  
   
   
       3 . The restraint system of  claim 1  further comprising a magnetic clutch for selectively operatively engaging the reel to the magnetic drag device;  
   
   
       4 . The restraint system of  claim 3  wherein the magnetic clutch is normally biased to operatively disengage the reel from the magnetic drag device, but configured to operatively engage the magnetic drag device upon the reel achieving a predetermined rotational velocity.  
   
   
       5 . The restraint system of  claim 1  further comprises a housing for encasing components of the system, the housing includes an attachment member for permitting the restraint system to be fixedly coupled to a vehicle member for attaching the restraint system to the vehicle, and a load support member.  
   
   
       6 . The restraint system of  claim 4  wherein the cargo item comprises a human being, and wherein, when the clutch is biased to disengage the reel from the magnetic drag device, the force required to move the tether in an unwinding direction is low enough to permit the cargo item to move about the vehicle generally unburdened by the retarding torque exerted by the magnetic drag device.  
   
   
       7 . The restraint system of  claim 1  wherein the magnet containing member includes an axis, and a magnet array comprising a plurality of permanent magnets disposed radially about the axis.  
   
   
       8 . The restraint system of  claim 7  wherein the conductor member comprises a cylindrical conductor member disposed in magnetic contact with the plurality of permanent magnets disposed radially about the axis of the magnet containing member.  
   
   
       9 . The restraint system of  claim 8  wherein the magnet array comprises a polygonal array of permanent magnets disposed radially about the axis of the magnet containing member, and the cylindrical conductor member is disposed exteriorly of the polygonal array of permanent magnets, the cylindrical conductor being in magnetic contact, but not operative mechanical engagement with the magnet containing member.  
   
   
       10 . The restraint system of  claim 7  wherein the magnet containing member comprises a first disk shaped magnet containing member having an axis and the conductor member comprises a disk-shaped conductor member having an axis disposed coaxially with the axis of the magnet containing member.  
   
   
       11 . The restraint system of  claim 10  wherein the magnet containing member includes a second disk-shaped magnet containing member having an axis disposed co-axially with the disk-shaped conductor member, wherein the disk-shaped conductor member is disposed between the first and second disk-shaped magnet containing members.  
   
   
       12 . The restraint system of  claim 1  further comprising a housing, and a central shaft on which each of the first and second disk-shaped magnet containing members, and the disk-shaped conductor member are mounted, wherein the first and second disk-shaped magnet containing members are fixedly coupled to the housing and the central shaft is rotatable with respect to first and second disk-shaped magnet containing members; and the disk-shaped conductor member is capable of being fixedly coupled to the central shaft for rotation with the central shaft and movement relative to the first and second disk-shaped magnet containing members for generating magnetic eddy currents.  
   
   
       13 . The restraint system of  claim 1  further comprising a retractor for retracting the tether when slack exists in the tether.  
   
   
       14 . The restraint system of  claim 13  wherein the retractor comprises a spring motor retractor.  
   
   
       15 . The restraint system of  claim 14  wherein the spring motor retractor comprises a coil spring.  
   
   
       16 . The restraint system of  claim 14  wherein the spring motor retractor has a predetermined operating range, and wherein the spring motor retractor applies a generally constant torque to the tether over the operating range.  
   
   
       17 . The restraint system of  claim 14  wherein the spring motor operates over an operating range between a first point where the tether is relatively more wound on the reel, and a second point where the tether is relatively less wound on the reel, wherein the spring motor retractor supplies a generally constant torque on the tether over the operating range.  
   
   
       18 . The restraint system of  claim 14  wherein the spring motor is rotatably coupled to the rotatable reel for rotation with the rotatable reel.  
   
   
       19 . The restraint system of  claim 18  further comprising a magnetic clutch for selectively engaging the reel to the magnetic drag device, the magnetic clutch including a portion rotatably coupled to at least one of the rotatable reel and spring motor, for rotation with the at least one rotatable reel and spring motor.  
   
   
       20 . The restraint system of  claim 19  wherein the magnetic clutch is normally biased to disengage the reel from the magnetic drag device, but is capable of operatively engaging the reel to the magnetic drag device upon the sensing of a predetermined rotation velocity of the reel, and wherein the magnetic clutch is rotatably coupled with each of the reel and spring motor to permit the magnetic clutch, reel and spring motor to rotate in unison.  
   
   
       21 . The restraint system of  claim 19  wherein the magnetic clutch operatively engages the magnetic drag device and the reel in response to the reel achieving a predetermined rotational velocity.  
   
   
       22 . The restraint system of  claim 1  further comprising a magnetic clutch for selectively operatively engaging the reel to the magnetic device in response to the reel achieving a predetermined rotational velocity, and 
 a retractor for retracting the tether when slack exists in the tether.    
   
   
       23 . The restraint system of  claim 22  wherein the retractor comprises a spring motor and 
 the spring motor and magnetic clutch are rotatably fixedly coupled to the rotable reel to permit the spring motor and magnetic clutch to rotate in union.    
   
   
       24 . The restraint system of  claim 23  wherein the magnetic clutch is capable of operatively engaging the magnetic drag device and reel at a rotation velocity achieved when the tether is extracted from the reel at a rate of between about three and five feet per second.  
   
   
       25 . The restraint system of  claim 1  further comprising a length controller for controlling the amount of the tether that can be unwound from the reel to thereby limit the distance that the cargo item can travel from the reel.  
   
   
       26 . The restraint system of  claim 25  wherein the tether comprises a tether having a predetermined length and the length controller comprises a variable length controller for permitting the user to vary the amount of the predetermined length that can be unwound from the reel.  
   
   
       27 . The restraint system of  claim 26  further comprising a control shaft upon which the reel is rotatably mounted, the control shaft including a threaded portion, wherein the length controller includes a follower ring coupled to the threaded portion of the central shaft, and a follower stop, the follower ring being capable of moving axially upon the central shaft upon the shaft, wherein contact of the follower ring and follower stop prohibits further rotation of the reel in an unwinding direction.  
   
   
       28 . The restraint system of  claim 27  wherein the length controller includes an adjuster for permitting the user to adjust the position of one of the follower ring and follower stop to thereby adjust the predetermined amount of the tether that may become uncovered from the reel.  
   
   
       29 . The restraint system of  claim 28  wherein the length controller includes a thrust bearing disposed at the end of the follower stop for preventing the follower ring from becoming bound against the follower stop.  
   
   
       30 . A magnetically actuated velocity change attenuator comprising: 
 (a) a rotatable reel,    (b) a flexible tether, having a first end coupled to the reel and a second end capable of being coupled to an item, the tether being windable around the reel, and movable in both a winding direction and an unwinding direction,    (c) a magnetic drag device including a magnet containing member having a plurality of magnets thereon, and a conductor member, the magnet containing member and conductor member being moveable with respect to each other, and one of the magnetic containing member and conductor member being capable of being fixedly coupled to the reel for movement with the reel,    (d) a magnetic clutch for selectively operatively engaging the reel to the magnetic drag device;    (e) a spring motor retractor for retracting the tether when slack exists in the tether; and    (f) a length controller for controlling the amount of the tether that can be unwound from the reel to thereby limit the distance that the item can travel from the reel 
 wherein movement of an item attached to the tether in a direction that causes the tether to move in an unwinding direction on the reel causes relative movement between the magnet-containing member and the conductor which generates electrical eddy currents in the conductor that produce a magnetic filed that creates a retarding torque on the reel that resists, but does not prevent, movement of the tether in an unwinding direction on the reel to thereby retard movement of the item.