US643597A - Safety device for elevators. - Google Patents

Description

Patented Feb. I3, |900. J. FLETCHER.

SAFETY DEVICE FUR ELEVATORS.

(Application led Sept. 14, 1899.) (No Model.) 2 Sheets-Sheet l.

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No. 643,597. Patented Feb. I3, |900. J. FLETCHER.

SAFETY DEVICE FQB ELEVATORS.

Z-Sheets-Sheet (Application led Sept. 14, 1899.) (No Model.) v

FIC-)-3 .TOI-IN FLETCHER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF THREE- EIGHTHS TO HARRY W. SPROSON, OF SAME PLACE.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 643,597, dated February 13, 1900.

Application filed September 14,1899. Serial No. 730,428. (No model.)

To all whom, it may concern:

Be it known that I, JOHN FLETCHER, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a certain new and useful Safety Device for Elevators, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to elevators, and has particular reference to safety devices used in connection with the cars of passenger and freight elevators and also upon mine cars, cages, or lifts; and one object of the invention is to provide, in connection with an elevater-car of any of the types above mentioned, simple, reliable, and effective means whereby in the event of the main hoisting-cable breaking the safety devices will be thrown immediately into operation, catching or gripping the guides at opposite sides of the shaft, and thereby preventing the car from falling. In connection with the safety device guides and shoes of novel construction are employed and two independent sets of devices are brought into play for the purpose of throwing the safety appliance in to operation, thereby insuring the engagement of such appliance with the guides.

Other objects and advantages of the invention will appear in the course of the ensuing description.

The invention consists in certain novel features and details of construction and arrangement of parts, as hereinafter fully described, illustrated in the drawings, and incorporated in the claims.

In the accompanying drawings, Figure 1 is a sectional elevation showing a sufficient portion of an elevator-car and the guides therefor to illustrate the application of the improvements thereto. Fig. 2 is a vertical sectional view taken at right angles to Fig. 1 and-looking toward one of the double-faced rack-bars, showing also the dogs and a portion of their operating mechanism. Fig. 3 is a vertical transverse section through one of the guides,

lshowing the manner of combining the several sections thereof. Fig. 4 is a horizontal crosssection through the same, showing also a sectional view of one of the shoes.

Similar numerals of reference designate corresponding parts in all the figures. Y

The car to which the improvements are ap= plied may be of any ordinary or preferred construction, l designating the sides or upright portion of the car, 2 the floor, and 3 the stationary cross-head by means of which the car is ordinarily suspended from the cable, indicated at 4t.) In the present instance, however, and in carrying out the presentimprovements an independent movable cross-head 5 is located above the stationary cross-head 3 and capable of movement toward and away from said stationary cross-head.

Mounted upon the end portions of the movable cross-head are sleeves 6, which receive the upper ends of a pair of rods 7, the said rods extending downward through the car and terminating near the floor thereof. The rods 7 are arranged as close to the sides of the car as practicable and preferably extend downward through openings 8 in the seats 9, where they enter housings 10, preferably of cylindrical form, arranged within and beneath and concealed by the seats 9. Each housing or cylinder 10 is provided with a cap 11, firmly secured thereto, and within each cyl'nder is arranged one or more springs 12, preferably of rubber, although it is within the scope of this invention to substitute for the rubber springs one or more spiral springs. The springs 12 are interposed between the cap 11 and a nut 13, threaded upon thelower end of the rod. A jam-nut 14 isV also placed on the threaded end of the rod 7 and turned up against the nut 13 to prevent the latter from working loose. It will thus be seen that the expansion of the springs 12 tends to draw downward the rods 7, and on vaccount of said rods being connected rigidly at their upper ends to the movable cross-head the latter is at the same time drawn downward toward the stationary cross-head 3, the object of which will hereinafter appear. 95

The main hoisting-cable .tis provided with a shackle 15, which connects directly with the movable cross-head at the point 16, and it will now be understood that the weight of the car and the load is suspended entirely from the upper movable cross-head through the medium of the supporting-rods 'Z and the IOO springs 12, acting in conjunction with the housings or cylinders within which the springs are located. By reason of this arrangement the springs 12 are normally compressed. \Vl1en,however,the cable t breaks, the springs l2 expand, with the result above set forth.

In connection with the construction above described l employ counterbalance-cables 17 and 1S, which run over suitable pulleys adjacent to the elevator-shaft and have applied thereto the usual weights for eounterbalancing the elevator. One of these cables 17 passes downward through the movable cross-head and around the grooved pulley 19, journaled centrally on the stationary cross-head 3, and thence upward obliquely, whereitis attached at its extremity to the movable cross-head at the point 20. The other counterbalance-eable 18 passes downward through the movable cross-head, under the pulley 19, and obliquely upward in the opposite direction, where it connects at the point 21 with the movable cross-head. From this it will be seen that upon breakage of the cable 4, as the elevatorcar begins to descend, the tendency of the counterbalance-weights is to uphold the cables 17 and 18, with the result that said cables operating around the pulley 19 and upon the movable crosshead will draw the latter downwardA toward the stationary cross-head, the mechanism being utilized for the same purpose as the springs and supporting-rods hereinabove described. Thus two independent sets of devices are used for moving the upper cross-head downward toward the stationary cross-head.

Mounted upon each side of the elevator adjacent to the guides 22 is a pair of clutchdogs 23, each of which is fulcrumed intermediate its ends, as at 2t, on one of the horizontal beams 25 of the car or upon any other convenient support. These dogs are provided with pointed engaging portions 26, facing toward each other and located on opposite sides of the guide 22. Connected to the outer ends of said dogs are rods 27, which extend upward to and connect pivotally with the movable cross-head 5 at the points 2S. Each of the guides 22 is provided at opposite sides with oppositely-projecting rack-bars having teeth 29, with which the dogs 23 are adapted to simultaneously engage. The dogs incline downward from their outer toward their inner or engaging ends and are normally held with their engaging portions out of contact and out of engagement with the teeth 29 of the double rack-bar. Vhen, however, the movable cross-head is drawn toward the stationary cross-head, the dogs 23, through the medium of the connecting-rods 27, are'rocked upon their fulcrums and their engaging ends thrown instantly into engagement with the opposite faces of the raekfbar, thus im mediately bringing the car to a stop.

The combined guide and rack-bar is preferably composed of three sections, 30 designating the inner or main section, 3l the outer section, and 32 the intermediate section,which extends laterally beyond the sides of the seetions 30 and 31, the teeth 29 being formed in said projecting portions. The several seetions of the combined guide and rack-bar are secured together by bolts orothersuitablc fasteners. The car is provided at suitable points with shoes 34, which are shown in seetion in Fig. 4. Each shoe comprises a body portion of a thickness equal to the distance from the inner to the outer surfaces of the combined guide and double rack-bar, and said shoe is provided in its body portion with a transverse opening 35 to receive the guide and also with oppositely-located grooves or recesses 36 to receive the teeth 29 of the rackbar. By this arrangementoppositely-located shoulders 37 are provided 0n the shoe, which coperate with the opposite side edges 38 of the teeth 29, by means of which the shoe and the guide are maintained in proper sliding engagement with each other, and the withdrawal or escape of the shoe from the guide is impossible. Each shoe is also provided with suitable ears or anges 39, having openings 40 to receive bolts or other suitable fastenings, by means of which the shoe is attached to the side of the car.

ln mining-cars or freight-elevators, where no seats are employed, the housings or cylinders l0, in which the springs are contained, may be secured to the sides of the ear adjacent tothe top or cross-head thereof, in which event the supporting-rods 7 will be correspondingly shortened in a manner that will be readily understood without further description or illustration.

From the foregoing description it will be seen that l have provided a simple, reliable, and effective means for catching and holding an elevator-car in case the hoistingcable thereof breaks. The clutch-dogs of the safety appliance do not depend for their operation upon a single operating means, but have the assistance of a second device, which also opcrates for the same purpose to throw the dogs into engagement with the guides. It will also be seen that by reason of the particular construction and relation of the shoes and the combined guide and double-faced rack-bar spreading of the guides is rendered impossible, and the shoes are maintained in proper working relation at all times to said guides and rack-bars. This also insures the proper alinement of the dogs with the teeth of the rack-bars, so that there can be no failure of the dogs to catch in the teeth when they are rocked upon their fulcrums bythe mechanism tripped or thrown in to operation by the breakage of the main cable.

It will of course be apparent that the safety device hereinabove described is susceptible of changes in the form, proportion, and minor details of construction, which may accordingly be resorted to without departing from the principle or sacrificing any of the advantages 0f the invention.

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Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is-

l. In a safety device for elevator-cars, the combination with the upper stationary crosshead of a car, of a superimposed cross-head movable toward and away from the stationary cross-head, a pair of dogs at the side of the car arranged upon opposite sides of one of the guides for coperation therewith, rods connecting said dogs with the movable crosshead, a counterweight-cable connecting the two cross-heads and auxiliary means coperating with and independently of said counterweight-cable for actuating the movable crosshead toward the stationary cross-head upon breakage of the hoisting-cable, substantially as described.

2. In a safety device for elevators, an elevator-car having a stationary cross-head, a superimposed cross-head movable toward and away from the stationary cross-head, a pair of dogs located on opposite sides of one of the guides for cooperation therewith, rods connecting said dogs with the movable crosshead, a counterweight-cable connecting the movable cross-head with the stationary crosshead, a rod connected to the movable crosshead and extending downward into the car, and a spring located within the car connected to said rod and exerting its tension to coperate with the counterweight-cable draw the rod downward and move the upper crosshead toward the stationary cross-head upon breakage of the cable, substantially as described.

3. In a safety device for elevators, an elevator-car having a stationary cross-head, a

'superimposed cross-head movable toward and away from the stationary cross-head, clutchdogs for engaging the guides at opposite sides G of the elevator, rods connecting said dogs with the movable cross-head, counterweight-cables connecting said cross-heads, rods connected to the movable cross head and extending downward into the car, spring-housings arranged under the car-seats and concealed thereby, and springs arranged therein and engaging the lower ends of said rods and acting to draw the rods downward and depress the J movable cross-head upon breakage of the cab'le, substantially as described.

4. In a safety device for elevators, an elevator-car having a stationary cross-head, a superimposed cross-head by which the car is suspended, movable toward and away from the stationary cross-head, clutch-dogs on the car for engagement with the guides at opposite sides of the car, rods connecting said dogs with themovable cross-head, a main cable connected with the movable cross-head, one or more counterbalance-cables extending downward past the movable cross-head, under a pulley on the stationary cross-head, and thence upward and attached to the movable cross-head, whereby upon breakage of the cable the counterbalance-cable serves to actuate the movable cross-head toward the stationary cross-head, and auxiliary means cooperating with said counterweight-cables,substantially as and for the purpose specified.

5. In a safety device for elevators, the combination with an elevator' car, and guides therefor having teeth along their opposite sides, of shoes secured to the car and embracing said guides, each of the shoes being provided with oppositely located grooves in which the' teeth are received, substantially as described.

6. Ina safety device for elevators, the combination with an elevator-car, of guides at the opposite sides thereof, each guide comprising a double-faced rack-bar and strips or sections of less width arranged upon the inner and outer surfaces of the rack-bar and bolted or otherwise secured thereto, and shoes se# cured to the car and embracing the combined guide and double rack-bar, each of said shoes being grooved to receive the teeth of the rackbar and to provide oppositely-located shoul ders for engagement with the opposite side faces of the teeth of the rack-bar, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN FLnToinrR.y

VVit-nesses:

Jos. F. ECKARD, CHARLES R. ODoNNELL.

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