US 3889777 A
A device to be strapped on a person for controlling descent down a cable or rope secured to an elevated structure. The device includes two endless chains of coacting teeth which intermesh in a linear channel to define a confining sinusoidal path for the cable which frictionally locks the chain to the cable. An adjustable braking mechanism controls the rate of chain travel, and thereby the rate of descent of the person wearing the escape device.
Description (OCR text may contain errors)
United States Patent [1 1 George 1 1 DESCENT ESCAPE DEVICE  Inventor: Clarence E. George, 419 Reeder Rd., Kleberg, Tex. 75145  Filed: Sept. 9, 1974 21 Appl. No.: 504,268
 U.S. Cl 182/6; 182/193  Int. Cl A62b l/14  Field of Search 182/5, 6, 7, 191, 192, 182/193; 188/654, 65.5; 254/154, 155, 156,
 References Cited UNITED STATES PATENTS 2,073,312 3/1937 Miller 182/7 [451 June 17, 1975 3,739,875 6/1973 Padwicki 182/6 Primary ExaminerReinaldo P. Machado Attorney, Agent, or Firm-Peter J. Murphy ABSTRACT A device to be strapped on a person for controlling descent down a cable or rope secured to an elevated structure. The device includes two endless chains of coacting teeth which intermesh in a linear channel to define a confining sinusoidal path for the cable which frictionally locks the chain to the cable. An adjustable braking mechanism controls the rate of chain travel, and thereby the rate of descent of the person wearing the escape device.
7 Claims, 7 Drawing Figures DESCENT ESCAPE DEVICE BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a device for use by individual persons for descending from an elevated structure by means of a suspended cable; and more particularly to such device which is worn by the user and engageable with a fixed cable.
The invention is concerned with the problem of escape from an elevated structure, such as a high rise building, in case of an emergency such as a fire.
An object of this invention is to provide an improved device of the type which is worn by an individual by means of a suitable harness or straps, and which is attachable to a cable fixed to the structure and suspended from a desired point reaching either to ground level or to a receiving platform at some lower level of the structure.
Another object of this invention is to provide such a device having a unique means for gripping the cable in the manner to prevent slippage between the cable and the device, and to completely and safely control the movement of the device relative to the cable.
A further object of this invention is to provide a de' vice having a pair of intermeshing traveling chains defining a frictionally confining path for coupling the chains to the cable, and brake means for controlling the travel of said chains thereby controlling the rate of descent of the device relative to the cable.
Still another object of this invention is to provide a device of this type having unique brake means for presetting the braking force acting on the cable engaging chains, and including an override control for either increasing or decreasing the braking force.
These objects are accomplished broadly in a device for coupling to a suspended cable comprising a generally flat housing including two side-by-side housing assemblies separable along a generally vertical parting joint; the housing being hinged at one end of the parting joint, and having latch means at the other end of the parting joint for closing the housing. The housing includes means for strapping the housing to the body of the person. An endless chain of pivotally connected teeth is supported in each housing part on at least two chain sprockets. Each endless chain comprises teeth with convex and concave projecting tabs arranged alternately. The housing, in closed condition, provides confronting walls defining a linear channel of a width to accommodate the cable and provides means for confining parallel runs of the two chains, with teeth tabs projecting into the channel in intermeshing relation to define a sinusoidal path. The housing channel walls and chain tabs thereby define a sinusoidal channel for frictionally confining the cable. The chains are interlocked to rotate together; and adjustable brake means mounted on the housing control the rate of rotation of at least one of the chain sprockets and, therefore, the rate of travel up the endless chains.
The novel features and the advantages of the invention, as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.
Drawings FIG. 1 is an elevation view of an escape device, including leg straps and a neck strap, as viewed from the front of the device when worn by a user;
FIG. 2 is a sectional view of the unit in the plane of the cable parallel with the front of the unit;
FIG. 3 is a transverse sectional view taken in the plane 3-3 of FIG. 2;
FIG. 4 is a detail illustration of the teeth for the endless chains;
FIG. 5 is a transverse sectional view through the lower sprockets and associated brake mechanism, taken in the plane 5-5 of FIG. 2;
FIG. 6 is a fragmentary sectional view illustrating brake mechanism details; and
FIG. 7 is a transverse sectional view, taken in the plane 7-7 of FIG. 6, illustrating details of the brake mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. I of the drawing is a front view of an escape device 11 as it would appear being strapped to the front of the wearers body, and attached to a suspended cable 10 which may be of any suitable structure and which may be a /8 inch stranded steel cable for example having a breaking strength of 2000 lbs. The cable would be permanently attached to the building or other structure, and of suitable length to reach ground level or a suitable safe platform level. The device would be attached to the torso of the wearer by a suitable harness, illustrated in FIG. 1 as a neck strap 12, a left leg strap 13 and a right leg strap 14 secured to the device housing by suitable strap slots.
In overall arrangement, the device is enclosed within a generally fiat housing which, as illustrated, may be generally square as viewed from the front, and which consists of left and right housing assemblies 17 and 18, respectively, which are separable along a vertical parting joint located centrally of the device 11. The housing assemblies are hingedly connected at the top by means of a hinge assembly 19, and are joined at the bottom of the parting joint by means of a latch assembly 20. The device is shown in closed condition in the figures.
The left housing assembly 17 consists of a main generally rectangular housing, defined by a rear wall 23 and a front wall 24, and a brake gear housing 25 secured together by suitable cap screws. An elongated channel wall strip 26 is secured to the rear wall 23 at the parting joint. Similarly the right housing assembly 18 consists of a main housing defined by rear and front walls 27 and 28 and a brake gear housing 29, and also a brake control housing 30. An elongated channel wall strip 31 is secured to the front wall 28 at the parting joint. All of the described housing parts may be fabricated from metal or any other suitable material. As best seen in FIGS. 1 and 7, the parting joint is defined by a front parting line 32 between the front housing walls 25 and 29 and the brake gear housings 25 and 29, and a rear parting line 33 between the rear housing walls 23 and 27; and these parting lines are laterally offset, with the channel wall straps 26 and 31 confronting each other but being secured to opposite housing assemblies.
The hinge assembly 19 consists of a hinge plate secured to the rear housing walls 23 and pivotally connected to the rear housing wall 27. The parting joint is open at the front of the device to permit insertion of the cable as will be described. The latch assembly as illustrated preferably consists of latch plates secured to the front and rear walls of the left housing assembly 17, and defining a yoke for receiving the right housing assembly and presenting aligned holes for receiving a wing bolt 21. Preferably the rear latch plate is threaded to receive the wing bolt, and a friction locking engagement may be provided to assure maintenance of latch engagement.
Referring now to the left housing assembly 17, an endless chain 36 is supported on lower and upper sprocket wheels 37 and 39 which are nonrotatably mounted by means of keys on shafts 38 and 40 respectively, journaled in the housing assembly walls. A backing plate 41, disposed between the sprockets, defines inner and outer opposite faces 42 and 43 for guiding and supporting the chain between the carrier sprockets.
The chain 36 is made up of alternate convex teeth 45 and concave teeth 46 connected close together by links 47. As best seen in FIG. 4, each concave tooth 46 includes a base 48 providing the means for pivotal connection to the coupling links 47, and a projecting platelike tab 49 which presents a concave edge surface facing away from the base 48. A recess 50 is provided on the opposite face of the base to receive the teeth of the sprockets 37 and 39. Each convex tooth 45 is similar in construction, including a base 51 provided with a sprocket recess and a plate-like tab 52 which presents a convex edge face facing away from the base. The convex and concave tab faces have complementary configurations to provide a uniform separation space as will be described. The above described teeth may be fabri' cated from any suitable material, such as a fibrous composition material for better frictional engagement with certain types of cables.
Referring now to the right housing assembly 18, an endless chain 56, identical to the chain 36, is supported on lower and upper sprockets 57 and 59 nonrotatably mounted on respective shafts 58 and 60. A backing plate 61 similar to the plate 41 has inner and outer edge faces 62 and 63.
It will be seen that, with the housing assemblies closed as illustrated, the teeth of the chains 36 and 56 intermesh with each other with the chains defining parallel runs along the parting joint and within a channel which is defined by the confronting backing plate edges 42 and 62 and the confronting channel wall strips 26 and 31. The teeth bases are actually defined between confronting edge faces of the backing strips and the channel wall strips; and the channel wall strips are spaced apart to accommodate the tabs of the teeth to permit sliding movement. The chains are disposed relative to each other, within the channel, so that the spaces between the confronting concave and convex teeth surfaces define a sinusoidal path dimensioned to receive and confine the cable 10. The teeth tabs and channel strips, then, define a closely confining sinusoidal channel, as best seen in FIG. 2, which prevents slippage between the cable and the chain teeth.
To insert the cable within its channel, the device is opened up by removing the latch screw and separating the housing assemblies 17 and 18 at the bottom to open up the parting joint. Since the hinge assembly 19 is open at the front, this will permit the laying of the cable 10 between the housing assemblies at the hinge joint and laying it partially within the channel defined by the left housing assembly 17. As the device is then closed along the parting joint, the cable will be guided into the sinusoidal channel.
Referring now to the brake mechanism and controls therefore, a master brake gear is a disk member with peripheral teeth, disposed within the right brake gear housing 29 and nonrotatably mounted on the shaft 58 for rotation with the sprocket 57. This master brake gear 70 functions as a braking disk, and is urged against an annular brake pad 71 of a suitable material such as asbestos for example, which is secured to the confronting face of the housing wall 28, by the brake shoe to be described. A slave brake gear 72 is disposed within the left brake gear housing 25 and nonrotatably mounted on the shaft 38 for rotation with the sprocket 37. In the closed condition of the device, the peripheral teeth of the master and slave brake gears mesh with each other as illustrated in FIG. 5, so that braking of the master brake gear and its associated chain 56 is directly imparted to the slave gear and its associated chain 36. A thrust bearing 64 is associated with the shaft 58 to absorb thrust forces.
The brake control housing 30 includes a cylindrical base portion secured to the housing 29, and an axially extending neck 75 having a square internal section. A brake shoe 76, preferably fabricated from a suitable metal, includes a generally cylindrical base dimensioned to be received within the housing base and an axially projecting square neck dimensioned to be received within the square neck 75 of the housing for a nonrotatable, sliding fit. The shoe base is provided with a central axial recess 77 to accommodate the shaft 58; and the circular face of the brake shoe confronting the master brake gear 70 is provided with an annular brake pad 78, fabricated from a suitable material such as asbestos for example, and secured to the shoe by means of screws for example. A recess 79 is provided in the end of the shoe neck to confine the end of a compression spring 80. It will be seen then that the brake shoe 76 is nonrotatably confined within the brake control housing 30 for rectilinear movement.
To adjust the pressure of the spring 80 acting on the brake shoe, the control housing neck 75 is provided with a cap 83 having a central bore for rotatably accommodating the reduced diameter shank of a threaded adjustment stud 84; and a knob 85 is nonrotatably secured to the projecting end of the stud shank whereby the stud is rotated relative to the housing cap. The stud 84 is provided with left hand threads; and a square nut 86 having left hand threads to receive the stud is dimensioned to be received within the housing neck 75 in nonrotatably and sliding relation. The compression spring 80 is confined between the brake shoe 76 and the square nut 86; and it will be seen that rotation of the adjustment knob 85 in a clockwise direction, as viewed from the exterior of the device, will move the square nut 86 toward the brake shoe to compress the spring 80 and increase the braking force applied to the master brake gear 70. Conversely, counterclockwise rotation of the knob 85 will reduce the spring compression and braking force. The cap 83 and knob 85 may have coacting indicia to indicate the braking force applied.
The brake mechanism is also provided with an easily operated override control by means of which the user can instantly increase or decrease the braking force which has been set through the adjusting knob 85. For this purpose the brake shoe neck is provided with a transverse axially elongated slot 90 provided with transverse rack teeth 91 on one face thereof disposed in a plane parallel to the longitudinalaxis of the brake shoe, as best seen in FIG. 6. A speed control shaft 92 extends transversely through the housing neck 75 and is journaled for rotation therein, passing through the shoe slot 90. The control shaft 92 includes an enlarged head at one end, and carries an intermediate elongated gear 93 disposed within the shoe slot 90 for engagement with the rack teeth 91. The shaft is retained within the housing by means of a suitable nut 94 and associated set screw for example. A control lever 95 is secured to the shaft head, extending radially therefrom for ready manipulation by the user of the device. As best seen in FIG. 5, rotation of this control lever 95 in a clockwise direction looking toward the shaft head 92, effects urging of the brake shoe toward the master brake gear 70, complementing the force of the spring 80 to increase the braking force. Conversely rotation of the control lever 95 counterclockwise moves the brake shoe against the force of the spring 80 to reduce the braking force. When the handle is released by the user, the braking mechanism automatically resets to the braking force preset by the adjustment knob 85.
While the brake mechanism is described in association with the lower sprocket of the left housing assembly, it will be apparent that the brake mechanism could perform its function in association with other sprockets.
Operation To briefly summarize the operation of this device, the braking force will have been preset by adjusting the adjustment knob 85 to effect the desired rate of descent for a particular user. or to effect a desired rate of descent for an average user.
At the time of emergency the device would preferabaly first be secured to the cable in the manner described, with the device being secured to the cable in position to enable ready subsequent securing of the device to the user. The device will then be secured to the user by suitable adjustment of the neck strap 12 and the leg straps 13 and 14; and the user will then position himself clear of the building structure for the controlled descent. The user may then use the control lever 95 for increasing the rate of descent if that is desired, or for slowing the rate of descent if that is desired, and even bringing himself to a stop if it appears desirable to terminate his descent at an intermediate level. Should the user release the control lever 95 either intentionally or inadvertently, the descent will be controlled by the preset braking force. The intermeshing chains 36 and 58 of course are frictionally locked to the cable 10 so that the controlled rate of travel of the chains through the described braking mechanism controls directly the rate of descent.
What has been described is a unique emergency escape device from an elevated structure for controlling the descent for individuals down a cable fixed to the structure. The device includes an adjustable braking mechanism for presetting the braking force controlling the rate of descent; and an override control mechanism which may be applied at the will of the user, either intermittently or otherwise to either increase or decrease the braking force and providing further control over the rate of descent.
While the preferred embodiment of the invention has been illustrated and described, it will be understood by those skilled in the art that changes and modifications may be resorted to without departing from the spirit and scope of the invention.
What is claimed is: l. A personal escape device for coupling to a suspended cable comprising a generally flat housing including two side-by-side housing parts separable along a generally vertical parting joint; said housing being hinged at one end of said parting joing, and having latch means at the other end of said parting joint for closing the housing; means on said housing for strapping said housing to the body of a person; an endless chain of pivotally connected teeth supported in each housing part on at least two chain sprockets; each endless chain comprising teeth with convex and concave projecting tabs connected alternately in closely spaced relation; said housing, in closed condition, providing confronting walls defining a linear upright channel at the parting joint, said channel being of a width to accommodate a cable; and said housing, in closed condition, guiding said chains to project said teeth tabs into said channel in intermeshing relation, with the confronting faces of the intermeshing tabs in spaced relation; said chain tabs defining a sinusoidal path for frictionally confining a cable; and said chains being interlocked to rotate together;
adjustable brake means mounted on at least one housing part, for controlling the rate of rotation of at least one of said chain sprockets and, therefore, the rate of drive of said endless chains.
2. An escape device as set forth in claim 1 said adjustable brake means comprising a brake disk member nonrotatably coupled to one of said chain sprockets; a brake shoe member mounted in said housing for nonrotatable rectilinear movement perpendicular to the braking face of said brake disk member and having a confronting brake face;
spring means urging said brake shoe into engagement with said brake disk member; and adjusting means for adjusting the force of said spring acting on said brake shoe.
3. An escape device as set forth in claim 2 said brake disk member comprising a gear member with peripheral teeth; a second gear member having peripheral teeth rotatably mounted on the other housing assembly and nonrotatably coupled to a chain sprocket for the other endless chain; said brake gear member and said second gear member being disposed for intermeshing engagement when said housing is in closed condition, whereby the braking of said brake disk member and its associated endless chain is effective for the second brake gear member and its associated endless chain.
4. An escape device as set forth in claim 2 a brake override mechanism comprising lever means and associated drive means for manually urging said brake shoe in a direction toward said disk brake member to supplement the brake force provided by said spring, or in a direction away from said brake disk member to override the brake force of said spring and reduce the braking effect of said brake shoe.
5. An escape device as set forth in claim 4 means on said brake shoe defining a rack having teeth disposed in a plane parallel to the axis of rectilinear movement thereof; a gear rotatably mounted in said housing having teeth in meshing engagement with said rack; and elongated radial lever means nonrotatably coupled to said gear for manual rotation thereof; and said rack, gear and lever defining said brake override mechanism.
6. An escape device as set forth in claim 1 said chains being disposed for rotation within said housing parts in a common plane; said teeth tabs being of a width to pass through said housing channel in free sliding relation, and having a tip face of either concave or convex configuration; each chain being made up of alternately connected concave and convex teeth to present an effectively continuous sinusoidal face within said channel confronting the opposite chain;
and said confronting sinusoidal faces of said chains defining said sinusoidal path for frictionally confining a cable.
7. An escape device as set forth in claim 1 each of said chain teeth comprising a relatively flat projecting tab and an enlarged base, said teeth being pivotally connected together at the respective bases;
each housing part having means providing a linear guide channel adjacent to its respective upright channel means; and the guide channel for each housing part being dimensioned to guide the bases of its respective chain teeth in a linear path adjacent to said upright channel at the housing parting joint.