Fire Escape	Detachable Fire Escape

Overview

History

Nicholas Rabelos patented several descenders:

• Fire Escape Device, U.S. Patent #3,504,763, April 7, 1970.
  • A descending manually controllable sleeve slides on a suspended support rope of requisite length. A sling serves to harness and seat the escapee and is operatively hung from the sleeve. Rope grips are built into the sleeve and frictionally grip the rope and are controlled by a knob-equipped hand regulated setscrew.
• Fire Escape Device, U.S. Patent #3,765,507, October 16, 1973.
  • A slidable, manually actuated device is mounted on the rope for longitudinal sliding movement in relation thereto with the rate of movement or descent being manually controlled by a person sup ported therefrom by the use of a flexible sling. The rate of descent is controllable by a screw-type rope clamping device which frictionally grips the rope for controlling the descent of a person along the rope.
• Fire Escape Device With Belt Tightening Slide, U.S. Patent #3,834,489, September 10. 1974.
  • The fire escape device includes a sleeve assembly that is constructed in the form of a generally rectangular block or body having a vertical passageway formed therein for receiving the rope. The passageway may extend from top to bottom end of the body and may be partially cylindrical in construction. One side of the passageway is defined by parallel walls which slidably receive a clamping plate. The clamp plate is also in the form of a block which extends from top to bottom edge of the body and includes a partially cylindrical or concave clamping surface which cooperates with the cylindrical or partially cylindrical passageway to frictionally clamp the rope when the clamp plate is moved inwardly in the passageway.
• Detachable Fire Escape Device, U.S. Patent #4,056,166, October 16, 1973.
  • An attachable and detachable slide is mounted on the rope for longitudinal sliding movement in relation thereto with the rate of descent being manually controlled by a person supported therefrom by a belt type sling. The slide includes a pair of hinged attached members having partial grooves in their facing surfaces for engaging the rope and a screw-threaded bolt and nut assembly connecting the hinged connected members for moving the facing surfaces toward and away from each other for varying the frictional engagement between the slide and the rope. The attachable and detachable slide facilitates a plurality of individuals escaping from the same building enclosure on a single rope. The slide includes a hook thereon over which the lower portion of the rope may be entrained so that a person on the ground may control descent of the slide by tensioning the rope.

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Storrick – Rabelos Fire Escape Device
(#3331)

Front	Rear

Side	Top

Technical Details

I made my Storrick – Rabelos Fire Escape Device in 2023.

This Squeeze Brake is 77 mm. tall, 97 mm. wide, 26 mm. thick, and weighs 404 g.

The squeeze brake consists of an aluminum housing, an aluminum pressure plate, and a threaded rod and oversized wing nut for slow friction adjustment. The block has a vertical milled and broached channel. One end of the channel is rounded to conform to the rope, the other is flat to match the rear of the friction block. The block us rectangular with a U-shaped groove on the side facing the rope. A shallow hole in the opposite side aligns the block with the adjustment screw. This screw is made from 5/15-18 UNC threaded rod. One end has a milled handle attached, while the other has the threads removed where it fits into the pressure plate hole.

The closure mechanism pivots on a free 5 mm. axle held in place by two set screws. Square at its pivot, it was turned and threaded (1/4-20 UNC) for an oversize wing nut. I added a lock nut to help prevent the wing nut coming free.

I stamped my logo on the front and rear.

Comments

I based this copy on the drawings in U.S. Patent #3,834,489,

Rigging requires having the free end of the rope accessible. This eliminates this device from anything other than emergency use when the device has been pre-rigged in anticipation of future use.

The pressure plate gives a large rope contact area that is good for heat dissipation, but the pressure plates does not provide adequate control. Friction is quite sensitive to the separation between the plates. Choosing the right thread pitch requires making a compromise. A course thread does not provide for fine adjustment, while a fine thread makes it difficult to rapidly increase friction when needed. My thread choice, coupled with the hard-lay caving ropes that I use, lies in the middle where neither function works well.

Warning: The Fire Escape's friction can vary quickly, widely, and unpredictably, leading to COMPLETE loss of control.

I do not like this Rabelos Fire Escape Device's design, but I like the harness described in the patent even less. The Fire Escape has no carabiner hole, just a small hole for threading a piece of accessory cord. In the patent, this would connect to a chest strap. The idea of hanging from a chest strap has manifest disadvantages, and I refuse to recommend it for anything other than leaving a burning room. In that situation, it might be the better option, but not having tested it in that environment, I'm merely speculating.

I give this one a Lemon Award .

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Storrick – Rabelos Detachable Fire Escape Device
(#3260)

Front	Rear	Top

Left	Right	Open for Rigging

Technical Details

I made my Storrick – Rabelos Detachable Fire Escape Device in 2023.

This Squeeze Brake is 185 mm. tall, 82 mm. wide, 102 mm. thick, and weighs 757 g.

The squeeze brake consists of two aluminum pressure plates with a threaded rod and oversized wing nut for slow friction adjustment. A 2 mm. deep, 11 mm diameter rope groove is milled vertically in the center inside surface of each plate. The front plate has a 101407 separable D Ring attached through a hole on a boss near the base of the plate. The rear plate has a Fortal hook attached with four screws. An aluminum piece screwed to the right side of the rear plate extends forward, where a captured pin through it and holes in the front plate serves as a hinge pin.

The closure mechanism pivots on a free 5 mm. axle held in place by two set screws. Square at its pivot, it was turned and threaded (1/4-20 UNC) for an oversize wing nut. I added a lock nut to help prevent the wing nut coming free.

I stamped my logo on the front plate.

Comments

I based this copy on the drawings in U.S. Patent 4,056,166,

The Rabelos Detachable Fire Escape Device design gives a large rope contact area that is good for heat dissipation. Relying solely on the pressure plates would not provide adequate control. Friction is quite sensitive to the separation between the plates, and a wing nut does not provide rapid adjustment. Rabelos added a hook to the rear plate. The rope is looped over the hook, which provides a snubbing action in addition to the friction from the brake itself. The knob can be adjusted so that most of the friction comes from squeezing the rope, while the snubbing provides an increase in friction as the tension below the device is increased.

Cavers once had considerable interest in squeeze brakes like this one, but following some severe accidents, our interest in squeeze brakes declined dramatically.

Warning: The Detachable Fire Escape's friction can vary quickly, widely, and unpredictably, leading to COMPLETE loss of control.

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