US236184A - John h - Google Patents

Description

(N0 Model.)

J. H. J. SCHMIDT. Pneumatic Brake for Elevators, 8L0.

Patented Jan. 4,1881.

FITG-l.

Invent Or yw-w -LITHOGRAPHER. WASHINGTON D. C

:peculiar construction of these pinions is seen I V UNITED STATES PATENT JOHN J. SCHMIDT, OF CINCINNATI, OHIO, ASSIGNOR OF ONE-HALF TO FRANK X. OEHLER, OF SAME PLACE.

PNEUMATIC BRAKE FOR ELEVATORS, 80C.

SPECIFICATION formingpart of Letters Patent No. 236,184, dated January 4, 1881.

Application filed July 22, 1880. (No model.)

To all whom it may concern:

Be itknown that I, JOHN H. J. SCHMIDT, of Cincinnati, Hamilton county, Ohio, have invented a new and useful Pneumatic Brake for Elevators, &c, of which the following is a specification. Y

My invention consists in applying a pneumatic brake either to the beam or frame or platform of a cage or carriage of I an elevator or other hoisting apparatus, which brake is automatically brought into action for the purpose of instantly arresting the descent of the cage the moment the cable breaks, or when, from any other cause, a certain predetermined descending speed is exceeded, the preferred construction of the brake being as follows:

A pump or other suitable compressor is attached to the car, and is set in motion during the descent of the latter, so as to force air into a tank or receiver and maintain therein any desired pressure-say forty pounds to the square inch-which pressure having been obtained, said pump is rendered inoperative for the time being. While the cage or carriage is making its usual trips this imprisoned air remains inactive, but the moment the cable breaks and the car begins to descend at a high velocity a governor or other regulator immediately opens a throttle-valve and allows the compressed air to rush into a cylinder and actuate a piston, which latter device brings into service the brake proper, ashereinafter more fully described.

In the annexed drawings, Figure 1 is a plan of the under side of the platform of an elevator car or cage provided with my pneumatic brake. Fig. 2 is an enlarged view of the brake proper. Fig. 3 is an elevation of the ratchet mechanism of the driving-shaft of the brake, and Fig. 4: is a modification of the invention. Referring to Fig. l, A represents the platform of a stage or car of an elevator or other hoisting apparatus; andB B are the customary Vertical guides or stanchions of the same, said guides being provided, respectively, with racks b b, wherewith are engaged pinionsc c, at the opposite ends of driving-shaft O. The

in Fig. 3, a reference to which illustration will show that the one o is loosely journaled on shaft 0 and carries a pawl, '01, that engages with the teeth of ratchet-wheel D, which latter is firmly keyed to said shaft. These ratchet-teeth should be set so as to insure the rotation of wheel D and its attached shaft 0 only when the stage or car descends.

E E are housings inclosing the ratchet' wheels, and a a are the journal-bearings for the shaft attached to said wheels.

Firmly secured at the mid-length of the driving-shaft O is a drum or pulley, F, surrounded with a brake-band, G, which band may consist of a flexible strap of steel or iron faced with rubber or leather or any other material capable of increasing the friction between said drum and brake. WVhen in its normal position the elasticity of band Gr maintains it out of contactwith pulley F, as seen in Fig. 2. This band is coupled by a link, g, to the short arm of a lever, H, the longer arm of which lever is attached to the rod i of a piston, I, which latter traverses cylinder J. The head of this cylinder, through which passes the rod "i, is perforated at j to prevent air being imprisoned between said head and piston I. while the other head is closed and has attached to it a pipe, K, leading to the tank or airreservoir L. which valve or cock is opened and closed by a governor or other suitable regulator, M, said It is throttle-valve of this pipe,

regulator being driven from shaft 0 by means of gearing m, or otherwise.

N represents an air pump or compressor, the piston-rod n of the samebeing driven from shaft 0 in any convenient manner, but, preferably, by means of an eccentric, O, riding loosely on said shaft and adapted to be set in motion as soon as aclutch, P, is engaged with said eccentric. This coupling of the clutch and eccentric may be effected with a spring, R, interposed between said clutch, and an adj ustable collar, 1, or by means of a weight attached to a counter-arm of bell-crank S, as indicated by dotted lines, one end of said crank being forked and engaged with the clutch, while the other endof the crank has applied to it the rod of a piston, T, traversing a small cylinder, t, that communicates with the air-reservoir L. U is a pipe that conducts the compressed air from pump N into said tank or reservoir.

The operation of this preferred form of my pneumatic brake is as follows: The governor M is first adjusted so as to keep the throttlevalve is closed while the carriage A is traveling at its ordinary or safe speed, and the 10 spring R is set so as to cause the clutch 1 to engage with the eccentric until a certain desired pressure of air has accumulated within the tank L-say forty pounds to the square inch. Theseprecautionshavingbcen observed, 1 5 the elevatoror hoisting-machine is started; but during its ascent no rotation of shaft 0 is effected on account of the peculiar arrangement of ratchet-wheels D, previously described. As soon, however,-as the staging or car begins to descend said shaft is set in motion, thereby actuating the compressing device N, and thus forcing air into the tank or receptacle L. This act of compression is repeated at every descent of the car until the desired pressure has been obtained, at which moment piston Tis forced from its seat in cylinder 2, thus swinging the belLcrank S on its pivot, so as to disengage the clutch 1? from eccentric O, and render the pump N inoperative for the time being; but it air should leak from the reservoir L spring R will cause the clutch P to re-engage with eccentric O, and again pump up the required pressure.

It will thus be seen that a supply of compressed air is constantly and automatically maintained in the reservoir, which air is utilized in operating the brake in the following manner:

Immediately on the severance of the hoisting cable or chain it is evident the car will begin to descend very rapidly, but the moment it does the high velocity thereby imparted to the governor M will cause the latter to open throttle-valve k, and allow the com- 5 pressed air to have access to the cylinder J,

and drive its piston I toward the perforated headj of said cylinder. This forward stroke of the piston swings the lever H 011 its pivot and draws the brake-band G so tightly around the drum F as to effectually pret'ent further rotation of shaft 0, and, consequently, the car is instantly locked in position and its further descent is at once arrested.

From this description it will be seen that my pneumatic brake is wholly automatic in all of its operations, and, therefore, it requires no attention from the person running the elevator.

In the modification seen in Fig. 4 the invention is shown as applied to those elevators the guides of which are armed with ratchetbars, wherewith are engaged pawls or detents carried by the main beam of the staging or platform. In this illustration the main beam A of the staging has fitted in it a cylinder,

J, traversed by a piston, 1, that carries a tapering plunger, V, seated in the stirrup W,

to which latter the hoisting-cable is attached in the usual manner. XX are inclined planes at the inner end of the rods that carry the 0 pawls or detents Y. K is the pipe that conducts the compressed air into cylinder J, said pipe being carried down through the platform, where it communicates with a reservoir similar to the one L. In this modification no governor or regulator is employed; but care must be taken to allow a sufficient volume of compressed air in the cylinder J to balance the weight of the hoisting rope or chain. Immediately after the breakage of this rope the compressed air is allowed to flow into said cylinder and depress its piston l, which act forces the wedge-plungerVdown between the two inclined planes X X, thereby compelling their respective pawls to engage with the 8 ratchets ofthe stanchions that confine the cage in a vertical path.

The invention may be further modified by employing a rotary compressor instead of the reciprocating one, N, which rotary device may either be applied directly on the shaft 0, or it may be geared or clutched thereto.

As the brake is brought into service only after a certain predetermined descending speed is exceeded, it is evident the action of the apparatus need not depend on the breakage of a hoisting cable or chain; but it is to this class of elevators my invention is more especially adapted. It may, however, be as readily applied to those platforms or stages attached directly to a piston or ram working water tight within a cylinder, so as to prevent the descent of said piston in case it should exceed a predetermined speed caused by the bursting of the cylinder or of any of its waterconnections.

In Fig. l the various operative parts are shown as situated in the same plane; but it is evident this arrangement may be varied without departing from the leading feature of my invention; and the right is reserved of changing the position of the brake or of entirely reorganizing the apparatus to suit the special construction or location of the elevator or hoister.

I claim as my invention- 1. In combination with a pneumatic elevator-brake, the driving-shaft O, air-compressor N, eccentric O, shiftable clutch P, lever S, piston T, cylinder t, spring R, and re- :20 ceiver L, which receiver communicates with said cylinder t for the purpose of permitting the compressed air to operate the piston T, as herein described.

2. In combination with the air-cylinder J, 125 pipe K, and tank L of a pneumatic brake for elevators, the throttle-valve 7c and regulator M, for the purpose described.

3. In combination with shaft 0, gearing with the racks b b of an elevator, the air-cyl- 130 IIO inder J, lever H, brake-band G, and drum F, In testimony'of which invention I hereunto which drum is attached to said shaft, as herein set my hand. explained- JOHN H J SCHMIDT 4. The combination ofdriving-shaft O, brake 5 apparatus F G H I J regulator is M.,reservoir Witnesses:

L, and compressing devices N O P R S T 1?, JAMES H. LAYMAN,

substantially as described. JEREMIAH F. TWOHIG.

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