US1505304A - Safety device for high-speed elevators - Google Patents

Description

Aug. 19, 1924.

M. A. BAKER ET AL SAFETY DEVICE FOR HIGH SPEED ELEVATORS 2 Sheets-Sheet 1 Filed Sept. 24, 1923 O h T 4 5 Z W m 5 v w, z 4 8 M. O M

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M. A. BAKER ET AL SAFETY DEVICE FOR HIGH SPEED ELEVATORS Filed Sept. 24. 1923 2 Sheets-Sheet 2 17 Fig. "w M H z J7 I 16 41 ,25 m z! I J9 Z Patented Aug. 19, 1924.

U NITED ST ATES PATEN T, oiuu(is :1

ivrrno A. nausea, HERBERT u. nuaanr, AND SAMUEL 1;. KING, or nos nnennns,

7 CALIFORNIA.

SAFETY *nnvrcn' 'ro ni HIGH srEnn ELEvAr'ons;

Application filed September 24, 1923. Serial No. 664,436. I

.To-mll whom it may camera:

Be it known that we, MILO A.. BAKER. HERBERT U. DURANT, and SAMUEL U. KING, citizens of the United States, residing at 25 Los Angeles, in the county of Los v Angeles and State of California, have invented a new and useful Safety Device for High Speed Elevators, of which the following is a specification. k

This invention relates to safety devices of the type employed. on high speed elevators for preventing falling of the elevator platform or cab in, event of the suspension cables breaking. y

An object of the invention is to effect gradual stoppage of the falling elevator platform within a comparatively short distance without shock.

In safety devices of this type of prior construction, a relatively great period of time elapses before engagement of the friction shoes with the elevator guides occurs, and,

consequently, the elevator platform'falls a considerable distance before the slowing, up

or braking action on the platform begins.

A further object of this invention is to begin frictional retardation of the falling elevator platform when the platform. has

dropped but a comparatively: short. distance and to then gradually and 'more slowly increase the friction so as to bring the elevator t a full stop very shortly thereafter.

A further object is to provide a device of this character of comparatively, simple construction so that there will be very little likelihood of it gettingout of order,

The. accompanying drawings illustrate the invention: I I y Figure 1 is a broken side elevation of-a safety device constructed in accordance with the provisions of this invention, the same being shown attached to the elevator platform beams and the elevator guides being omitted in this view. 7 I

Fig. 2 is an inverted plan section on line 2-42 of Figure 1, the elevator guides being shown in place. I v

Fig. 3 is an end View of Figure 2, omitting the guides. I Fig. 4 is an enlarged fragmental plan, partly in section, from the linejindicated by 4.-4, Figure 1. j

-Fig. 5 is an end view of Figureii from the left thereof.

Fig. -6 is a plan view similar a ri id,

but showing less of the shoe-operating arms, and the drumshaft is turned sufficiently to" disengage the clutch and cause the rollers to ride uponthewedge-sleeve. a

Fig. is a fragmental end 'ew of Figure ,6 from thelefttxhereof', the position ofthe-wedge sleeve shown in Fig. 4." I 4 zF-ig 8 is a sectional elevation on the line indicated'by 8+8, Figure 6. I

. A governor-controlled drum .isindicated at 11. The governor and cable that serve to .set this drum into operation are not illustrated or describedfherein since their construction and operation are well understood in, the-art relating to elevator safety devices. It suffices to state that, the governor is adjusted so that if the elevator plat-, form "attains a dangerous speed in descend? .ing, as, for example, in case the suspension cables break, the governor operates to cause a cable, not "shown, wound onthe drum 11 to" be held stationary and thus turn said drum in the direction of thetarrow a in Figure 1. a The drum 11 is:mounted on a shaft 12. having screw-threads 13 at its opposite ends, the screw threads being the reverse of ,eachother, that :is to say, those at one :end being left hand and those at the other "right hand. The bearings of the shaft 12 are indicated at 14 and are formed in a yoke 15 which is bolted to the under face of a pair of platform beams 16. The foregoing described construction is well understoodin this art. I 1 i Means are provided to press shoe against one of the elevator guides and, in this instance, said means-are operated com par-atively fast by turning of the shaft 12 less than one revolution in one direction to engage the shoe with the guide and operated at aslow'errate by further turning of the shaft to more and more forcibly engage the guide.v These means may be variously constructed. and the invention in its broader phases is not limited to the particular means corresponding to that V illustrated: The construction of said means,

now to be described, is provided in duplicate at opposite ends of the shaft Y12 and,

consequently, it will be necessary to describe 'only'Ythat at one end; The screw threads 13 engage athreaded nut17 which provides f at one end. a female clutch member 118 Y lent, to the drum shaft so as to be turned by said shaft. During the normal operation of the elevator the clutch members 18, 19'will be in'engagement as in Figure 4: so that turning of the drum will. rotate the nut. I

The nut 17 is free to turn in a wedgesleeve 21., said sleeve being held against longitudinal movement relative to the nut by a suitable locking pin 22, or its equivalent. The wedge sleeve 21 is provided with longitudinally extending slots 23, the bottom walls 24 of said slots being aslant toward the axis of the drum shaft in a direction leading away from the clutch members or,

in other words, toward a pair of rollers 25 which are sufficiently narrow to enter the slots 23. The rollers 25 are rotatably mounted on shafts 26 which are supported,

respectively, in pivotally mounted levers 27. Each of the shafts 26 projects sufliciently beyond the levers 27 to engage the hookshape ends 28 of a coil spring or springs 29 which, consequently, tend to hold the rollers 25 normally in contact with flattened or cam faces 30 ofthe nut 17, these faces 30 being contiguous to the portion .31 upon which the wedge sleeve 21 is mounted.

The pivots for the arms 27 are indicated at33 and are mounted in a member 34: that is bolted to the underface of the beams 16.

Pivoted at 35' to the'levers 27 is the shoe or shoes previously referred to and these shoes are indicated at 36 and are arranged on opposite sides of one of the elevator guides 37 so thatiwhen the rollers 25 are thrust outwardly by the wedge sleeve 21, the shoes 36 will be caused to frictionally engage the guide 37. The parts just described are proportioned so that frictional gripping of the guide by the shoes 36 takes place when the rollers 25 have ridden off of the cam faces 30, as in Figure 6. Resuming the description of the means operating the shoes, the nut 17 is provided at its periphery with a pair of shoulders 38, 39, the shoulder 38 being, adapted to be brought into engagement with a shoulder 40, on the wedge sleeve 21 when the nut is turned in the direction indicated by the arrow 7) in Figure 8, and the shoulder 39 being adapted to engage a shoulder 41 on the wedge sleeve 21 when the nut is turned in adirection opposite to that indicated by the arrow 6, or in the direction of the arrow (1, Figure 1.

The invention above described operates, as follows:

Assuming that the parts are in the positions in which they are shown in Figures 1 and 50f the drawings and that the elevator suspension cables have broken, permitting the elevator platform to drop at a dangerous speed, the drum 11 will be caused to rotate in the direction of the arrow or because ofthe operation of the elevator governor at a speed higher than that at which the safety device is to remain inactive, in a manner Well understood in this art, thus rotating the shaft 12 in the direction of the arrow 0, Figures 5,7 and 8. This rotation of theshaft rotates the clutch 18, 19, thus rotating the nut and causing the rollers 25 to ride off of the cam faces 30 onto the higher cam faces 32, operating the levers 27 to cause the shoes 36 to operate comparatively fast to frictionally grip the elevator guide 37. This rotation of the clutch also causes the shoulder 39 to engage the shoulder 41. This occurs in less than a quarter of a turn of the shaft 12, and causes the nut 17 to be held against further rotation and, in consequence, said nut is translated from the position shown in Fig. 4, to the left thus disengaging the clutch members and causing the slanting slot walls 24 to wedgedly move the rollers 25 away from each other and thusto gradually contract the shoes 36 at a slower rate upon the elevator guide 37, until the friction between said shoes and guide becomes so great as to bring the elevator to a stop. Thus, it will be seen that there are provided means to first effect relatively quick contraction of the shoes 36 upon the guide 37 and thereafter relatively ,slow contraction of said shoes upon the guide. By these means the shoes are moved from position giving ample clearance between them and the guide to a gripping position within a period of time in which the drum shaft makes less than one revolution or, in this instance, only about one-quarterof a revolution. This enables a falling elevator to be gradually stopped within a distance that is less than that between two floors of a building.

The guide-blocks, shown at 42, are of the usual type employed on the elevator platform for engaging the guides 37 and, therefore, need not be described in detail herein.

It will be readily understood from the foregoing description that the nut 17 constitutes a membermounted for rotation and translation, that the cam face 30 operates upon rotation of said member, that the slanting face 21 constitutes a cam face for the nut operating upon translation of said member, that the rollers 25 constitute one form of follower which may be otherwise constructed, and that the drum '11, shaft 12, screw threads 13, clutch 18, 19 with the shoulders 39, 41 constitute means operable to alternately rotate and translate said member. I

We claim:

1. A safety device of the characterdescribed comprising a shaft, a shoe, and means operated comparatively fast by turning of the shaft less than one revolution in one direction to press the shoe against an elevator guide and operated at a slower rate by further turning of the shaft to more and more forcibly engage the guide.

2. A safety device of the character described comprising a shaft having screw threads, a nut engaging the screw threads, means operated by the shaft to releasably engage and rotate the nut, means to hold the nut against rotation after it has been rotated through a certain number of degrees of circular measurement, a shoe, and means operated by the rotation of the nut and thereafter by translation of the nut to move the shoe toward an elevator guide.

3. A, safety device of the character described comprising a member mounted for rotation and translation and provided with a rotative operated cam face and with a translation operated cam face, a shoe, a follower operatably connected with the shoe and successively engaged by the respective cam faces, and means operable to alterna tively rotate and translate said member.

Signed at Los Angeles, Calif, this 17th day of September 1923.

MILO A. BAKER. HERBERT U DURANT. SAMUEL U. KING.

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