US600825A - swain - Google Patents

Description

(No Model.) 2 Sheets-Sheet l.

E. A. SWAIN. SAFETY BRAKE FOR ELEVAT'ORS.

Patented M1". 15,1898.

Af/ 4l ATTORNEY (No Model.)

2` Sheets-Sheet 2. E. A. SWAIN. Q

SAFETY BRAKE POR BLEVATORS.

/ @mmvmmmmg WA/ W Patented Mar. 15. `1898.

WITNESSES: KJZOM I, um

r I lNvENToR ff 2M/MQW ATTOR N EY rrn @rares EDWARD A. swAiN,

on NEW YORK, N. Y.

SAFETY-'BRAKE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 600,825, dated March 15, 1898.

Application filed December' 10, 1897. Serial No. 661,432. (No model.)

fthe fall or the sudden ascent of an elevatorcar in the event of an accident to the hoisting rope or machinery. To this end I provide a safety or emergency rope which in the event of an accident, causing a sudden fall of the car or its too rapid movement in either direction, will be deflected across the elevator-shaft, so as to intercept the carin its movement and gradually bring it to rest.

In the accompanying drawings, Figure'l is a sectional elevation of an elevator, showing the safety device in its proper normal position when the car is running regularly, as in ordinary use. Fig. 2 is an elevation showing the position of the parts when the car is intercepted in falling. Fig. 3 is an elevation of the lower part of the elevator and its accessories, showing the safety apparatus in normal position on a larger scale. Fig. L't is a plan of the same.

1 represents the elevator-car, and 2 the hoisting-rope thereof, both of which may be mounted and guided in any usual or suitable manner. To the car 1 is attached a governorrope 3, which, in connection with thecar 1, to which it is attached, forms an endless rope passing upward over one or more sheaves l and downward around a sheave 5, keyed on a shaft 6, connected by beveled pinions 7 with a centrifugal ball-governor S of common form set to any desired limit of speed. The governor-rod 9 is pivoted to a-nearly horizontal har 10, resting at its outer end on a fulcrumpoint 11, and provided on top, just within the fulcrum-point, with a concave block 12, forming a cradle for the support of a heavy cylindrical weight 13, which is pivoted in a yoke 14, to which are attached the extremities of the safety- ropes 15 and 16.

The safety-rope 15 is suspended at 17 from the top of the elevator-shaft, passing down on one side of the elevator-car 1 and in normal working of the elevator rests on the bottom of the shaft or on a floor f, extending across the shaft below the lowest movement of the car, as shown in Fig. ,1. Its lowerI end is passed between apair of clutch-sheaves 18 19, one of which, 18, may be a common cylindrical sheave Yrunning on a Xed shaft, while the other, 19, is mounted eccentrically on its shaft 2O and is so arranged, as clearly shown in the drawings, that the safety-rope 15 will pass outward between the clutch-sheaves without resistance, but on the application of anystrain tending to draw it back will be tightly gripped by the eccentric sheave 19, so as to be immovably held in that direction. The second safety-rope 16 is attached at 21 to the bottom of the elevator-shaft passing, upward on one side of the car through the eyebolt 29, the shank of which is inserted, as shown in Fig. 1, in the frame near the top of the shaft, holding with sufficient friction to retain the rope '16 in the vertical position Vshown during the normal Working .of the elevator. From this eyebolt the rope 16 passes horizontally across the top of the shaft between a pair of clutchsheaves 22 23, similar to the clutch-sheaves 18 19, and operating in the same manner to permit the ropeV 16 to run freely outward, but to instantly grip and hold it against being drawn inward.

In order to keep the governor-rope 3` at the proper tension, it is passed around guidingsheaves 24 25 and a sheave 26, journaled in a yoke 27, from which a weight 28 is suspended. By this device the governor-rope 3 is allowed to run freely with the car 1, imparting a regular movement to the governor S by friction upon the sheave 5, while the weight 2S keeps the said governor-rope at a uniform tension.

Operation: In the ordinary normal working of the elevator the cylindrical weight 13 rests in the cradle 12 of the bar 10 with its center of gravity just within the fulcrumpoint 11, as shown in Fig. 1, the parts being so arranged that in this normal position of the apparatus the bar 10 will be inclined inward, so that the gravity of the weightv 13 will give it a tendency in -that direction, its movement being arrested by the concave block or cradle 12. In the event of the breakage of the suspension-rope 2 or other accident causing a too rapid descent of the car 1 the accelerated motion of the governor 8 will im- IOO mediately throw up the inner end of the horizontal bar 10, as shown in dotted lines in Fig. 3, causing the weight 13 to roll outward off the end of the bar and fall, as shown in Fig. 2, drawing the safety-ropes 15 16 out through the eccentric clutches 18 19 and 22 23, so as to deflect the said safety-ropes across the shaft above and below the car, as illustrated in Fig. 2. This will quickly apply considerable resistance to the descent of the car, so as to gradually retard its descent, and' thisv resistance will become greater and greater as the angular deflection of the rope increases and will infallibly arrest the descent of the car before it reaches the bottom of the shaft. As soon as the pressure or strainI exerted by the descending car upon the rope l5 is sufficient to overcome the gravity of the weight 13 the inward strain applied to the rope 15, acting by friction on the eccentric sheave, instantly brings the clutch 18 19 into action, so as to grip the rope with increasing friction. The safety-rope 15 will thus be tightly and securely held at any point to which it has passed between the sheaves 18 19. In like manner the safetyrope 1o' will be deected across the elevator-shaft above the car by the detachment of the eye 29 from the frame and will be held by its clutch-sheaves 22 23, so as to prevent the possibility of the too rapid ascent of the car in the event of any accident which would cause such dangerous upward movement.

Chains may be substituted for the emergency-ropes 15 16, and afriction-clip of common form may be substituted for the detachable eye 29 to retain the rope 16 in vertical position in the normal operation of the elevator.

The invention evidently is not restricted to the particular form or construction of the emergency-rope, so called; but by this expression I intend to include any equivalent form of flexible material.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

1. In combination with an elevator-car and the shaft in which it ascends and descends,

an emergency-rope resting normally out of the path of the car and means for deiiecting and securing the said rope across the path of the car, substantially as described.

2. In combination with an elevator-car and the shaft in which it ascends and descends, 'a' pair of emergency- ropes 15, 16, and means for deiiecting, and securing them respectively lacross the lower and upper parts of the elevator-shaft so as to intercept the car in either falling or rising movement, substantially as described.

3. The combination of an elevator-car, l, emergency- ropes 15, 16, adapted to be deflected across the shaft in which said car moves, and automatic clutch-sheaves, as 18, 19; 22, 23 operating to permit the said emergencyropes to run freely outward, in drawing them across the path of the car, and grip them against inward movement, substantially as and for the purposes set forth.

4. The combination of an elevator-car 1, a centrifugal governor 8, controlled in movement by that of the car, an emergency-rope, as 15, adapted to be deflected across the elevator-shaft, and a tripping device, as 11, 12, 13, for throwing the said emergencyrope across the elevator-shaft in the event of abnormal speed of the governor, as explained.

5. The combination of the elevator-car 1, an emergency-rope resting normally out of the path of the car, a weight 13, governor 8, and tripping device 10, 12 for causing the deflection of the emergency-rope across the path of the car; substantially as set forth.

6. The combination of the elevator-car 1, emergency-rope 16, separable guide 29, weight 13, and a suitable tripping device therefor substantially as and for the purpose set forth.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 3d day of December, 1897.

EDWARD A. SWAIN. Witnesses:

WM. BATES,

JOHN W. FLECKE.

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