US932726A - Balanced-pressure elevator. - Google Patents

Description

G. F. STEEDMAN.

BALANOED PRESSURE ELBVATOR. APPLICATION FILED MAB. 12,1909.

Patented Aug. 31, 1909.

imi-,nn #STATES f PATENT GEORGE r. s'innnmamors'r. Louis, MISSOURI.'

' BALANcED-Pnnssunn Eraiva'roa specification cftea'eis Patent. Patented Aug. 31, 1909.

i A Application filed March 12, 1909.` Serial N`o482,938. y l

To all whom it may concern; A Y

Be it known that vI, GEORGE F. STEEDMAN, a citizen of the United States, `.residingat St. Louis, Missouri, `have invented acertain new and useful `Improvement in Balanced# Pressure Elevators, of` which the following is a full, clear, and exact 'descriptiomsuch as will enable others skilled in `the `art to which it appertainsto make and use the same. y 1v This invention relates to pneumatic ele-v vators, and particularly pneumatic elevators in which the cylinder is directly under-5 neath the cage.,`

In my 'numerous priorpatents, I have.

shown several different types of pneumatic elevators. In the direct type, the `'cylinder is placed directly overthe elevatorcage, and

the piston rod is connected directly.to the.-

upper part of the cage.v the-'rope.type, the cage is lifted by means of wire `rope' attached to the upperportion ofthe cage.`

In both the direct and ropetype elevators,

the piston rod is in tensionV and lifts the cage by pulling on it.

The types of der be` directly underneath or platform.

The object of my present invention is tol adapt the use of a pneumatic `hoisting cylin der to a direct-acting elevator, in which the cylinder is directly underneath the platform and raises the platform by pushing itlup-k ward.

A further object of my invention is to prof vide an elevator of and reliable. Y

The accompanying drawing represents an elevator' of this type and illustrates the preferred embodiment ofmy invention.

this type, whichis safe It is usually desirable inl elevators of thisclass that the support on which the load' rests be in the nature of a platform and` not" a cage. The luse of a shallow platform'ref quires that the `piston rod .be `sufficiently strong to support without distortion they platform when theentire load is carried `near one end or side` thereof, which necessitates` a piston rod of comparatively large diam` eter. f

elevators just ydescribed are not suitable for certain special uses, as, lforV instance, what istermed a sidewalk :ele-` vator where itis necessary that .the cylinthe elevator cage The figure of the drawing is a vertical sectional view `of an elevator, embodying my upresent invention. i

Referring to said drawing, A designates the cageor platform of an elevator which travels on vertically disposed tracks 1, and BL designates the operating cylinder that is arranged underneath said cage. The piston 2in said cylinder has a `piston rod 3 connected to its upper face, and said rod projects through a stufling box 4,1 in the upper end ofthe cylinder,and is connected to the lower sideof the cage A.

.Theactuating fluid, which is preferably air underfpressure, is contained in a tank,

vnot shown,andrsaid tank communicates with fa supplyV pipe 5, that leads to the casing 6 of a two-,waycontrolling valve C, said supply ipipe 1 having "a branch" 7 that communicates `with the lower end of the cylinder. A pipe Sthat communicates with the upper end of the cylinder, leads to said valve casing 6, and said valve casing is provided with an eX- liaust `pipe 9, that communicates with the atmosphere.

The means employedin the elevator-herein shown for controlling the actuating fluid to and from thecylinder is similar to that shown in my prior patent No. 840,876, dated January 8th, 1907,so that I will only briefly describe the operation of said means.

' "The supply Apipe 5 -is provided with a check valve 5'f1V arranged between the branch 7 and-the supply tank, so as to prevent the fluid from backing up into the supply tank,

and.- said 1Vbranch 7 leads to a speed-control-- "ling-box" 10, having a pair of oppositely opening-cheek valves 11 and 12, that permit by the arrows.

valve 12, permits the fluid on the underside ofthe piston to exhaust from the lower end Vof the cylinder,-when `the cage descends.

Thev pipe 8 that is tappedinto the casing of the controllingvalve C, communicates with aspeed-controlling box 15 having an inwardly opening check valve 16- that cooperates with a pipe 16.a which leads to the uptend to move it in a direction -to raise the .10

.per end of thecylinderfsaid box also having an outwardly opening check valve l? that cooperates with a pipe 1.7.a whichleads to the upper end of the cylinder. As thebranch 7 from the supply pipe communicates atl all times with the lower end of the cylinder,V

theniotiueforce will be constantly exerted on the underside of the pistonl and thus cage.V

'Ehe direction of movement of: the cage 'is goyelned .by the controlling: valve4 C,

which is adapted to be turnedzinto such aV position, that. the fluid ou the upper.- .side

of f the pistony can escape through. the pipe 1.7?, .speed-.controlling box 15..,.and pipe. 8 to the exhaust pip@ 9; that lende from the cas- Y ingx of; the. controlling-valve. The elevator is so.. designedy .that lthe cageV dees not stop betareenitsupper anellower levels., and when the; eageapproaeheszether of levels, its.

f' speed graduallyA reduced .by means. of

plungers 18` and l19 lon'the lower;and!upper` 7 Sidesnt; the .pist-en thatprojeet into cushioning chfunbers` ldfand 1.9a inthe heads of the vcylinde asshown and. v.clearly described ing ehaniherse When the Cage is at its upper level. and it Y is d.(Vesiredfto;have Vit desoend,the valve C is: turned inteisueh. a position that commu.- nicati'on willbe established between the sup- Y ply pipe 5:. and the .pipe 8.,. thus permitting upperY side off the. piston,V soi as 'to balance.

the fluid t0. enten the upper end-.of the. cylinder and..V exert dewnward, pressure 011 the the' upward pressure or force. that isv ex.- erted on the; lower side. ofthe piston.. In

f view. of.: the feet that the pieten lied is lelge and -scenneeted to.- theupper .Side of they piston, the. area of the upper, face of the pieten, is mush lessv than the ereafef the lenierface Of the piston, .se that the. enge Wouldenetdeseend when it net provided with a leed,Y if seme ineens. in addition to.

the. fluid. .thatis intredueed-- inta ,the upper.I endr of the eylinderV were net. vprovided.,lier

@Verema-ing; the. eXeessifve pressure that. the.

fluid exerts en the under sdeiefzthe piston.

"' eel'eeed;.the upward; pressure.r that. the'. fluid Theneiere., I; have se designed 'the cage. and the, pistQnrOdthat the combined-weight ofseineg'j plus the pnessunej that the Yfhuid; eX:

entsfon'the. upperside of the. piston Willv exentsen the unden 'side et thepsten rlhis resultcan. be accomplished; in va-riouswvays,

-suehi'fen example, es presiding. the enge. -with n heavy inenihen D. that is conneeted tothe cage,

0fthe ease. Seidjlnelnhen D eddseneugh.

Permanently set that it. terms part.

4equalized. In other words, the

weight to the cage, so, that the combined weightwoui' the cage and piston rod will be suiicient to cause the cage to descend unthe pressure on both sides of the piston is pistou rod and empty cage have .suliicient weight to return themselves against the unbalanced forces 'ofthe hoist, it beingunderstood, of course,

that the location of the piston rod on the. upper side of; the` piston4 prevents .the forces of the hoist from being; in balance. I prefer to. use the member D.7 which isformed of iron or sonic other heavy material: and provided with recesses 2l. that, canv be filled withsoine.suitable heavy materialthat adds Weight te the. cage, thus. enabling. the peruiaf nent weight on the pistonl rod to be. varied by placing ,material in the recesses of the nienibeul) or removing it therefrom. I do net uishte. he understood, however, that my hleadideais limited teithis exact construe. tion7 for the piston can be weighted in nllllr. ereue other ways, without departing from the. spirit lofjniy iilivention,

Inniy previousvpaten-ts, Iy have shown the use Qfthebeleneed pressure air. heist adapt..

ed to pneumatic elevators where the pistons aeten the Cage hapulling. In the type ef vel,ev'ater herein illustrated; namely, one 1n which thepisten 11nd iseenneeted t0 the under side 0f the eege,-d.ireet air pressure has heretofore beenused but such an elevatoris not safe.

VIn an elevator of the character herein described, but operated on. they single actingprinciple, pressure would-be admitted to the lower sidel of the piston to raise the load and exhausted freni said lower side toilowen the load. If the empty cage were forced, upward,` only comparatively light air, pressure wouldbe required toraise the eage,rand

ifbswhenthe cagereaehed its upper level, the,

full, load the elevator isg designed fork were placed,` uponI the Gage, there. would not be suflicient lsustaining power underneathjthe piston. and2 the. cage would descend, until the air. inthe cylinderr was compressed,` suiioiently to support the load. Witlt the. bal-` anoed hoist,` principle herein-k showlnhoweuer, the action isdecidedly dilferent. Air under full pressure is constantly admitted to the. lower sidevof the piston, anda-ir inust be exhausted; froin the upper sidelof the pistou.A to

Vpermit the cage'to ascend, and whentlie cage.

hasreaolredA its uppeu limit, there. is the full.

supporting pressure exerted on the undenside offthepiston, and; the air all exhausted from the upper side ofi-thc pistonLsothat the full` load can be placed upon thecage im mediatelyl upon its arrivah at the, upper limit. With this explanation, it is obvious.

rod would apparently `prohibit* the use` of" the balanced pressure'hoist, and itis only by means of the novel expedient of adding sufficient weight to the ordinary. rod and anced air hoist to elevators as herein described. y

I have spoken only of pneumatic elevators throughout, but it is apparent that" steam Aor any gas under pressure canbe used in place of compressed air, and when I speak, in the claims, of pneumatic elevators, Iwish it to be understood that steam 'or any other gas under pressure can be substituted.

Having thus described myinvention', what I claim as new and desire to secure by Let-V ters Patent is: i j Y l. In a balanced pressure hoist, a cylinder provided with a piston, a piston rod connect-` ed to the upper side of said piston and pro-V j ectng upwardly through the upper end'of said cylinder, a direct connection between the lower end of the cylinder and a supply of fluid under pressure, and means for introducing fluid under pressure intothe upper end of the cylinder to causethe piston to move in one direction and for exhausting the fluid from the upper end of the cylinder to cause the piston to move in the" opposite direction, the piston rod carrying a permanent load which is of sullicient weight to lcause said piston to descend when the actuating j fluid is introducedinto the upper end of the cylinder. Y j

2. In a balanced pressure fluid-actuated hoist, a cylinder provided with a piston "having a piston rod that projects upwardlyV through the upper end of thecylinder, said rod being adapted to have a permanent load imposed on the upper end thereof, the lowerv end of t-he cylinder being in constant comp-` munication with a supply of fluid under pressure, and means for introducing a balancmg pressure into the upper end `of the cylinder and exhausting it therefrom, the

weight of the piston rod and the permanent load thereon being sulficient to cause the load to descend when the pressure on the two sides of the piston is equalized.` j

3. In a balanced pressure elevator,a cylinder provided with a piston,a piston rod connected to the upper side of said piston and projecting upwardly through a stuffing box in the upper end of the cylinder, a cage or supporting platform connected to the upper end of said piston rod, meansfor` establishing a direct connection betweenvthe lower end of the cylinderand a supply of fluid under pressure so that upward pressure will be constantly exerted on the lower side of the piston, and means for admitting a fluid' under pressure into the upper end of the,

cylinder and exhausting it therefrom, the weightof` 'said cage and piston rod being suliicient to cause the cage to descend when the pressure of the actuating fluid on the two sidesof the piston is equalized. cage that I have been abletoemploythe bal- 4, Ina -balanced pressure Huid-actuated elevator, a cage, a cylinder arranged under the cage andprovided with a piston, a rod connected to the upper side of said piston for sustaining the entire weight of said cage, said rod being `of great enough cross sectional area that it will not bend when the cage 1s loaded unevenly, means for establishing direct `connection between the lower end of the cylinder and a supply of fluid under pressure, a controlling valve for admitting fluid under pressure into the upper end of the cylinder andfor exhausting it therefrom, and a permanent weight carried by said cage to compensate for the space which the piston rod takes up in the cylinder and thus cause the cage to descend when the pressure on the opposite sides of the piston is equalized.

5. In a balanced pressure fluid-actuated elevator, an v operating cylinder provided `with aplston, a' piston rod connected to the upper side of said piston and projecting upwardly throughastufling box in the upper end of the cylinder, an elevator cage or platform connected `to the upper end of the piston rod, saidcage being so constructed that permanent weights can be added thereto or taken away therefrom to vary the permanent weightimposed Von the piston rod, a supply pipe leading from a supply of liuid under pressure and communicating with the lower end of the cylinder, so as to cause pressure j to be exerted on the lower side of the piston constantly, andra two-way valve for exhausting fluid from the upper side of the piston to permitthe cage to ascend and for Y introducing fluid onto the upper side of the piston, to cause the cage to descend.

`6. In a pneumatic elevator, wherein the cylinder is underneath the platform, a source of` compressedair connected directly to the lower end of the cylinder, andconnected to the upper end "of the cylinder, by means of a two-way Y valve, permitting the flow of compressed air into or out of the upper end vof the cylinder, the combined weight of the empty platform and piston rod being sufficient to" cause the cage to descend, when the compressed air is admitted to both ends of the cylinder.

7.` Iny a pneumatic elevator of the character described, a balanced pressure air hoist arranged topush on the piston rod, the motive pressure` being connected to the lower `end of the cylinder, the balancing pressure being admittedito andlexhausted from the upper end! of thefcylinder, and the piston the lower end of the cylinder, thebalancing pressure being connectedby means of a two'- 'Way valve to the upper end of the cylinder, and the piston rod and empty cage having 15 sulicient Weightto return the empty cage agamst the unbalanced forces of the hoist,

Vwhen the balancing pressure is admitted to the upper end of the hoist.

In testimony whereof I hereunto alix my 20 signature in the presence of two Witnesses, this ninth day of March, 1909.

GEORGE F. STEEDMAN. Witnesses Gno. E. HOFFMANN, WILLIAM F. HARRISON.

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