referring to fig1 escape device 11 includes a carriage comprising a rectangular housing 13 . housing 13 is divided into a first or upper compartment 15 and a second lower compartment 17 , separated by a horizontal partition 19 . a door 21 forms the bottom of the lower compartment 17 . a hinge 23 connects one side of door 21 to the back wall of housing 13 . an upright flange 25 , mounted to door 21 on the upper side and opposite hinge 23 fits inside of the housing 13 front wall when the door 21 is in the closed position , shown in fig2 . an aperature 27 extends through the center of flange 25 . a pin 29 extends slidably through an aperture in the front wall of housing 13 to engage aperture 27 . pin 29 , flange 25 and hinge 23 serve as fastener means for releasably securing the door 21 to the housing 13 in a closed position as shown in fig2 . a vertical partition 31 divides upper compartment 15 into two sections . in the left section , or subcompartment , a reel or drum 33 is rotatably mounted . referring to fig2 drum 33 is mounted on an axle 35 for rotation therewith and with respect to housing 13 . axle 35 is rotatably mounted into vertical partition 31 on the right , and into another vertical wall 37 on the left . an arm 39 is secured to axle 35 for rotation with the axle and drum 33 . arm 39 extends perpendicular to axle 35 for a distance approximately 1 / 2 the drum diameter . a pin or finger 41 extends from the free end of arm 39 perpendicular to it and away from drum 33 . arm 39 and finger 41 comprise the output member in drum 33 . a small diameter steel cable 43 capable of holding about 1500 pounds is wound around drum 33 . cable 43 has an inner end ( not shown ) secured to drum 33 and an outer or free end 45 secured to a hook 47 outside of housing 13 . hook 47 is for securing to an eyelet ( not shown ) mounted inside the building at an appropriate place . alternately , end 45 may be affixed to a permanent connection in a hallway storage cabinet where fire extinguishing equipment is normally kept . cable 43 passes through an aperture in the top of housing 13 , guided by a guide roller 49 mounted to the inner side of the top of housing 13 . roller 49 is spool - shaped and rotates with respect to housing 13 as the cable 43 plays out . the length of cable 43 is selected to be sufficient for the user to reach the ground or a safe lower level . cable 43 is wound around drum 33 only in a single direction . a sheath or enclosure ( not shown ) may be mounted about drum 33 to prevent uncoiling of the cable 43 when no tension is on the cable . a speed governor 51 or retarding means for limiting the rotational speed of drum 33 during descent of device 11 is located on the right side of partition 31 . partition 31 divides the upper compartment 15 into a drum compartment on the left and a governor compartment on the right . speed governor 51 comprises a multiple gear reduction train of the type commonly used to reduce the rotational speed of electrical motors and increase their torque . referring to fig2 and 3 , gear train 51 has a low speed input member or shaft 53 coaxially aligned with drum axle 35 . input shaft 53 is journaled between two vertical walls 55 and 57 of a subhousing for the gear train 51 . input shaft 53 has a transverse slot formed on its end closest to drum 33 . this slot closely receives the straight and inner end portion 59 of a coil spring 61 . coil spring 61 is a flat band of spring steel formed into a coil , and serves as shock absorber means for absorbing shock due to jerking of the cable . the outer end 63 is bent into the shape of a hook to be engaged by finger 41 of arm 39 . spring 61 lies in a plane normal to the drum axle 35 . spring 61 is wound clockwise from the inner end 59 to the outer end 63 when viewed as in fig3 . unwinding cable 43 tends to wind or compress spring 61 into a tighter coil . the stiffness or bias of spring 61 is selected so that under torque exerted by a user of the heaviest weight expected , a substantial amount of further compression or winding will still be possible . spring 61 absorbs shocks from jerks on the cable 43 by further compressing , thus not transmitting the rapid acceleration due to jerks to the speed governor . the intermediate members of the gear train 51 include a first spur gear 65 mounted to input shaft 53 for rotation therewith . gear 65 is located between vertical walls 55 and 57 and on the left side . a pinion 67 is mounted in engagement with gear 65 . pinion 67 comprises a shaft journaled between walls 55 and 57 , and having longitudinal splines that mesh with the teeth on gears 65 . a second gear 69 , smaller than the first gear 65 , is mounted on pinion 67 for rotation therewith . second gear 69 has teeth that mesh with a second pinion 71 . a third gear 73 , smaller than the second gear 69 , is mounted on the second pinion 71 for rotation therewith . third gear 73 engages a third pinion 75 . a fourth gear 77 , smaller than the third gear 73 , is mounted on third pinion 75 for rotation therewith . fourth gear 77 engages a fourth pinion 79 . a cylindrical balance or weight 81 is mounted to fourth pinion 79 for rotation therewith . balance 81 is the highest speed member of the gear train 51 and comprises a solid cylinder , except for the hole through which the fourth pinion 79 extends . pinions 67 , 71 , 75 and 79 are parallel with drum axle 75 , are journaled between walls 55 and 57 , and all have longitudinal splines for engaging gear teeth . in fig3 balance 81 is shown partially broken away . referring to fig2 the body support means for carrying the user during descent includes a transverse bar 83 extending between the sidewalls of housing 13 in the lower or strap compartment 17 . as shown in fig1 a nylon strap 85 has two ends ( only one shown ) that are formed into loops 87 for receiving bar 83 . strap 85 defines a loop for placing around the user &# 39 ; s arms and around his chest for descending . in operation , should a fire occur , the user breaks or opens a window . he then clips cable hook 47 to an eyelet in the building previously provided , unless the end 45 is already permanently affixed to some component in the building . the user then pulls out sufficient cable 43 to be near the open window . he pulls pin 29 , which releases door 21 to the open position , as shown in fig1 allowing strap 85 to fall out . he places strap 85 around his chest and under his arms , and jumps or drops out the window . as he descends , cable 43 turns drum 33 , playing out the cable . drum 33 rotates arm 39 , which rotates coil spring 61 and the speed governor input shaft 53 through finger 41 . shock from the jump or other jerks will tend to further wind spring 61 . this absorbs some of the shock on the cable 43 , and also the shock that otherwise would be transferred to the gear train 51 . input shaft 53 of gear train 51 will be rotated at the same speed as drum 33 . shaft 53 rotates the first gear 65 at the same rotational speed . being considerably larger than the pinions , first gear 65 rotates pinion 67 at a considerably higher rotation speed . first pinion 67 drives the second gear 69 at this higher speed . second gear 69 rotates the second pinion 71 at a still greater speed , since it is larger in diameter than pinion 71 . pinion 71 drives third gear 73 at this speed . third gear 73 drives third pinion 75 at a higher speed since it is larger in diameter than pinion 75 . pinion 75 drives fourth gear 77 at this higher speed , which in turn drives the fourth pinion 79 and weight 81 at the highest rotational speed . due to the multiple gear reduction from weight 81 to first gear 65 , the speed of the user will reach a fairly safe velocity until the user reaches ground . no handbrake is needed , although one could be provided if desired . the descending velocity of the user depends to a great extent on the mass of weight 81 . weight 81 is selected so that the descent speed will accelerate only to a safe , substantially constant velocity . the velocity will depend on the weight of the user , and also varies as the cable unwinds , and the safety drum diameter decreases . to provide a selected safe velocity with a 20 to 500 pound load , the gear train had the following dimensions , when fully wound , the drum diameter was about 2 1 / 2 inches . under a 260 pound load , the velocity was a safe level of about 1 / 2 foot per second . it should be apparent that an invention having significant advantages has been provided . the escape device has a speed governor that effectively and sensitively governs speed without the need for a fluid restriction device or friction contact . no manual brake is necessary . shock on the cable is reduced by the shock absorber , avoiding damage to the cable and to the speed governor . the housing allows the strap to be compactly folded for storage . while the invention has been shown in only one of its forms , it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes and modification without departing from the spirit thereof .
an escape device for allowing an individual to descend from a damaged building . a drum and cable is mounted in a housing . the free end of the cable is secured to a part of the building , allowing the user to descend as the cable plays out and the drum rotates . a multiple gear reduction train mounted to the drum automatically limits the descent speed . a coil spring shock absorber forms the connection between the drum and gear train to reduce shock . a strap is folded inside a separate compartment in the housing below the drum and gear train . the strap is placed about the user &# 39 ; s body during the descent . a quick release door in the strap compartment provides access to the strap .