US1373944A

US1373944A - Elevator safety apparatus

Info

Publication number: US1373944A
Application number: US314644A
Authority: US
Inventors: Boehck William Edward
Original assignee: REVOLVATOR Co
Current assignee: REVOLVATOR Co
Priority date: 1919-08-01
Filing date: 1919-08-01
Publication date: 1921-04-05
Anticipated expiration: 1938-04-05

Description

W. E. BOEHCK.

ELEVATOR SAFETY APPARATUS. APPLICATION FILED AUG-1. 1919.

1,378,944. Patented Ap1i5, 1921.

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J52 0622222" ZMZWM$M llEl TATE FAB WILLIAM EDWARD IBOEHGK, 0E JERSEY CITY, NEW JERSEY ASSIGNOR T0 I:,EV'()1', TOR COMPANY, OF JERSEY GT'IY, NEVI JERSEY, A CORPORATION OF NEW JERSEY.

ELEVATOR SAFETY APPARATUS.

Patented Apr. 5, i921.

Application filed August 1, 1919 Serial No. 314,644,

T 0 all whom it mag concern Be it known that 1, WILLIAM EDWARD Boer-raga citizen of Germany, residing at Jersey City, in the county of Hudson and tate of New Jersey, have invented certain new and useful Improvements in Elevator Safety Apparatus, of which the following is a specification, reference being had to the accompanying drawings.

This invention relates to improvements in safety devices for elevators and particularly to improvements in safety devices for tiering machines (otherwise known as portable elevators), the purpose of which devices is to prevent the dropping of the load-carrying platform, in case the hoisting-cable should break; and an object ofthis invention is to provide a safetydevice of the kind just mentioned, which will be simple in construction, comparatively cheap in manufacture, and eiiicient and durable in operation and use, and the cost of repairs of which will prove small. Another object of this invention is the provision of means whereby. the engagement of the holding cams with the elevator-standards is prevented or obviated, in case the operator should slacken the hoisting cable sufiiciently when the platform hasbeen lowered so that the same rests upon the bottom structure or base of the elevator.

In the drawings illustrating the principle of this invention and the best mode now known to me of applying that principle, Figure l is an elevation of so much of a tiering machine as is necessary to illustrate this invention; Fig. 2 is a side view, looking in the direction of the arrows in Fig. 1, the view being partly in section on the line 22 of Fig. 1; and Figs. andd are de tails illustrating the toothed r holding or clutch cam in side and front elevation, respectively.

As isuconventional in structures of this class, the tiering machine is provided with a pair of uprights or standards a, which are made of channel-iron or of steel, as may be preferred. There is one of these standards a at each side of thetiering machine; and each standard a comprises a web a fromeach vertical edge of which there projects inwardly a flange a thereby giving to the standard at its channeled form. The load-receiving platform 6 is (as is shown in Fig. 2) horizontally disposed and is carried,

by the Ushaped lifting-frame or guideframe 0 that consists of a pair of upright guide-arms c, the lower ends of which are connected by a cross-beam a". A pair of inclined braces 0* (Fig. 1) joins the latter with each of the arms 0. When the liftingframec is raised, it carries with it the.load-' receivmg platform 6." From the upper end of each arm 0, there extends laterally and outwardly a stub-shaft or arbor d,'which pro ects into the channel of the opposed ma' chine-standard a and uponwhich is rotatably mounted a guideroller e. The flanges a" of the machine-standard to serve as tracks upon. which the guide-roller 6 travels. The lower end of each arm or upright 0 of the lifting-frame c is similarly provided with an outwardly and laterally projecting rollershaft d upon which turns a lower guide roller 6' that runs on the flanges a" as tracks in the same manner as does the upper guide-roller e.-

l'iorizontally disposed beneath the rigid cross-bar 0 of the lifting-frame 0 there is a loose hoisting crossbeam f to the front and rear faces of which there are fastened, by means of the ping, the lower ends of a pair of pull-straps or pull-links h, which extend upwardly from. the-loose cross-bar. f and between which lies the rigid cross-bar 0 of the load-carrying platform 6. The lower end of .the hoisting-cable i enters between the upper ends of the pull-links hand is formed with a loop i,=through.which and i allowed to descend.

From near the middle of each guide-arm 0", and between the roller-carrying shafts ol, d,

there extends laterally and outwardly a camcarrying shaft In which projects into the channel oftlie opposed machine-standard w and upon which there is mounted, free to swingga holdingor clutch cam m of. an almost semi-circular shape (Figs. 3 andd). The hole at. through which passes the pivot or shaft lc is eccentrically located in the holding-cam m, and, from the top of the latter, there extends upwardly an ear m 7 formed with a perforation m". The convex face n ofthe cam m is beveled or inclined from one of its edges to the other thereof, in order that, the face a may conform to the bevel or inclination of the opposed face of the flange a, of the machine-standard a; and; in order to allow for the inaccuracies or inequalities of the bevel of this opposed face, the face 12 of the cam on is slightly rounded. Ratchet teeth n are formed in the face 12 for the purpose of increasing the gripping action of the cam m, when the latter is thrown against the flange a opposed thereto. From the ends of the loose lifting crossbeam 7, there project horizontally the lugs f the free ends of which are perforated to receive the lower ends of the Z-shaped linkrods 0. The upper end of each linli-rod o is fitted into the perforation m formed in the ear m of the cam m,- and when the loose hoisting'cross-beam moves downwardly with relation to the platform cross-beam 0", the connecting link-rods 0 transmit the 1110- tion and rock the two holding cams m on their pivots or shafts is, so that the toothed cam-faces 72 are pressed into clutching engagment with and against-the beveled faces of the flanges a of the machine-standards a and there results a frictional gripping action of the cams m therewith. At each side of the machine, there is provided a coilspring 79 the lower end of which is attached to the adjacent guide-arm c and the upper end of which is fastened to that end of the connectingrod 0 which enters the ear 0??" of the cam m on that side of the machine (Fig. 1). These coil-springs p tend to throw the connecting-rods 0 downwardly and cause the same promptly to follow any drop of the loose cross-beam relatively to the fixed cross-beam'c of the platform 2') and thereby to insure quick action of the clutch-cams m.

The operation of the safety contrivance described hercinhefore may be briefly set forth as follows and will be readily understood. So long as the hoisting mechanism of the tiering machine operates normally, the pull of the hoisting-cable i (acting in one direction) and the weight of the platform 5 and the load thereon (acting in the opposite direction) hold the two horizontal crossbars 0", f, firmly pressed together and V maintain the clutch-cams m in the full-line CII (or inoperative) position shown in Fig. 2, against the tension of the coil-springs When, however, the hoisting-cable breaks, the loose cross-beam f will drop relatively to the rigid or fixed cross-bea1ns a of the platform guide-frame c and will fall away therefrom, the co1l-springs pwill contract and the holding-cams m will be rocked on their pivots Z4 so as to force their toothed cam-faces n into frictional clutching contact with the opposed faces of the flanges a of the standards a. The result of the rubbing of the "toothed faces at of the cams m against the flanges a is that the eccentrically-mounted cams m are given a rolling motion and theguiderollers c are forced with intense pressure against the opposite ;e of the flanged channel-beam a, whereby great frictional resistance to the downward movement of the platform 6 is produced and the same is brought to rest and held up, despite the rupture of the hoisting-cable i.

it is to be observed that the cams on are mounted, and therefore act, independently of each other, whereby the stresses produced by the sudden throwing of the weight of the platform and the load thereon upon the standards a are distributed between the latter, instead of being concentrated upon a single standard, which concentration results in those cases in which the holding-cams are mounted on a common shaft and hence are compelled to act in unison, and when the structural shapes a differ slightly from each other in form and dimensions of the channel and its walls, a difference that is practically always to be found in the structural shapes a as'they are commercially produced and marketed. Due to such slight inequalities, one of the cams at will engage before the other; and, if the two cams were mounted on a common shaft, one cam would almost surely come into gripping action, while the other would not engage effectively with the flange a of the guidestandards a, from which it would result that the standard a upon which the load would be thrown would be forced to sustain the weight alone or to collapse. Of course, when the collapse of the standard :es place, the disaster that follows is greater by far than if the loaded platform 7) were to drop; liable to occur, particularly in case the platform Z) is loaded to the capacity of the ma- ;hine.

Should the operator permit the hoistingcable 71 to become slack, while the platform I) is resting upon the bottom-structure or base 9 of the elevator, the holding-cams m are liable to be thrown into frictional engagement with the standards ca In order to obviate such engagement underthe conditions just mentioned, the following arrangement of parts is provided, namely: From the loose lifting cross-beam f, there extends'or projects downwardly a pair of posts or bolts 7 the lower ends of which are threaded and pass through holes formed in a horizontal bar arranged parallel tothe lifting-beam f. The bar 5 is held on the posts or guide-bolts 1 by means of the nuts t that are screwed on the projecting threaded ends ofthe poster. Mounted on the latter and interposed between the lifting-beam f and the bar 8, there are compression-springs it which tend to hold the bar 8 against the nuts "25 and, thereand such collapse is veryrest upon the elevator-base 9, there are the stop-brackets '0. When, therefore, the platform 2) rests upon the elevator-base g and the hoisting-cable i is slackened, the liftingbeam 7 and the platform-crossbar 0 will nevertheless be found to be held firmly.

pressed together by the tension of the coilsprings a, the bar 8 bearing upon the stopbrackets q; at this time; and the holdingcams m will be maintained in their normal or inoperative position. Should the hoisting-cable 2' become slack (as in case of the rupture thereof), while the platform I) is above the elevator-base g and the bar .9 is above the stop-brackets o, the lifting-beam f, the bar 8, guide-posts r and coil-springs u will, as a unit, fall away from the platform crossbar 0', thereby throwing the holdingcams on into frictional engagement with the faces of the flanges a" of the guide-standards a in the manner and by the means already fully described hereinbefore.

This application is filed as a continuation in part of my pending application, Serial No. 30487 5, filed June 17, 1919.

I claim:

1; Elevator safety apparatus for tiering machines, including a hoisting mechanism; a pair of fixed standards; a load-carrying platform mounted to travel therebetween; platform-guiding rollers arranged to travel along said standards; a lifting-beam below said platform and supported by said hoisting mechanism, said lifting-beam being free to move downwardly relatively to said platform in case said hoisting mechanism ceases to support said lifting-beam; cams mounted free to turn independently of each other and arranged to travel in close proximity to said standards; and cam-actuating devices connecting said cams and lifting-beam and arranged to throw said cams into frictional engagement with said standards when said lifting-beam falls relatively to said platform, whereby said platform-guiding rollers are forced into frictional engagement with said standards and the platform is held from dropping.

2. Elevator safety apparatus for tiering machines, including a hoisting mechanism;

a pair of fixed standards; a load-barrying platform mounted to travel therebetween; platform-guiding means arranged to travel along said standards; a lifting-beam below i said platform and attached to said hoisting mechanism, said lifting-beam being free to move downwardly relatively to said platform in case said hoisting mechanism ceases to support said lifting beam; devices for throwing said platform-guiding means into frictional engagement withsaid standards when said lifting-beam falls relatively to said platform; and mechanism for preventing the operation of said devices when the platform is supported otherwise than by the hoisting mechanism.

3. Elevator safety apparatus for tiering machines, including a hoisting cable; a pair of fixed standards; a load-carrying platform mounted to travel therebetween; aliftingbeam below said platform and attached to said hoisting cable, said lifting-beam being free to move downwardly relatively to said platform in case said cable should become slack; devices for preventing the fall of said platform when said cable becomes slack or ruptures, said devices being thrown into 5 operation by the fall of said lifting-beam; and mechanism for preventing the operation of said devices when the platform is supported otherwise than by the hoisting cable.

4:. Elevator safety apparatus for tiering machines, including a hoisting cable; a pair of fixed standards; a load-carrying platform mounted to travel therebetween; a liftingbeam below said platform and attached to said hoisting cable, said lifting-beam being free to move downwardly relatively to said platform in case said cable should become slack; devices for preventing the fall of said platform when said cable becomes slack or ruptures, said devices being thrown into operation by the fall of said'lifting-beam; and mechanism for holding said liftingbeam and platform against separation from each other in case they are supported otherwise than by said cable.

Signed at Jersey City, New Jersey, in the presence of the two undersigned witnesses this 23rd day of uly, A. D. 1919..

WILLIAM EDWARD BOEHCK.

Witnesses Hnnwre BonHoK, FERDINAND Manson.