US1989419A - Lock mechanism - Google Patents

Description

G. D. HILL LOCK MECHANISM Jan. 29, 19 35.

2 Sheets-Sheet 1 Filed April 21, 1931 INVENTOR @rrLZZHLZL Jgm. 29, 1935. e. D. HILL 9 LOCK/MECHANISM Filed April 21, 1931 2 Sheets-Sheet 2 Patented Jan. 29, 1935 i UNITED 'STATE5PATENT Sargent 8t Greenleaf, Inc.,- Rochester, N. Y., a corporation of New York Application April 21, 1931, Serial No. 531,736 16 Claims. (01. 70-26) H This invention relates to a lock mechanism within the member 14' so that by turning the han- -which may be used, for example, in connection dle 16 the member 14 and the bolts 12 may be with a safe or vault. An object of the invention moved back and. forth from looking to unlocking the provision of lock mechanism of simple position, and vice versa, whenever suchmoveoicharacter, having relatively few moving parts, ment is not obstructed by one or another. of .the;.--

employing noclockwork, springs, escapement, or look mechanisms employed. gears, which cannot be circumvented from the; At 20 there is illustrated conventionally'a casoutside of the safe or'vault. i 1 ing of a combination lock of any usual orordinary Another object of the invention is the=provision Co st uction havin t usual Operating spindle of a lock mechanismoperative to release a bolt or 21 connected to the usual knob on the outsidexof 10 the like after a, predetermined time interve1, the door. A disk 22 is fixed to the spindle near the which mechanism is simple and relatively inexinner end thereof. ,When the tumblers havebeen pensive to construct, which is accurately timed, Properly set by manipulation ofthe kn'obythe bolt and which is fully automatic so that n springs 23 of the combination lockmay be withdrawn' so "need be wound and no settings-need be made preha i 0 l n r obstructs unlocking movement of viously inorderto insure properoperation of the e be twork 0f the door. i J timingmechanism at the desired ti e, Also mounted on the inner face of the door 11 A further object is the provision of such a time there is .a time: 100k c an s .O novel and lock mechanism in, combination with another greatly p fi d form, w c in t p ese p Ilock, so that operation of'the other lock will inir d embodiment mploys 110 Spr ngs, gearsi'orfi .tiate o crationofthe time lock mechanism. o k o a d which is p e a d c mp a v y T th andtothepd th inv ti id inexpensive to construct. This time, lock mechain certain improvements and combinations of ah s Operates on t general p p pparts, all as will be hereinafter more fully de- P a qua t ty of fluid and then releasing this ;seribed,th ve1 f at r being pointed t fluid at a predetermined relativelyslow rate, vso. 2 5

the claims at the end of the specification. i that it takes a predetermined time interval for a In the drawings: 1 a r given quantity of the trapped fluid toescape. Fig; 1 isan elevation f the inside face of a safe a After t predetermined qua y as p d, oor showingthe application of one embodimen d-not until then, the mechanism is moved-to- 30. of th r ti v nti th t unlocked position so that the boltwork-or otherc3 'Fig. 2 is a fragmentaryview of some of the desired parts controlled by the time, lock mechaparts shown in Fig. 1, illustrating them in a. difnism y be moved in the desired'way. 'ferent iti 3 The-term fluid as used here and inthe ac- Fig. 3 is a fragmentary view of part of theapcompanyingclaims is intended in a broad 'sense paratus shown in Fig. 1 ona larger scale, with and is meant to includenot-only substances which 13 parts in vertical section; 4 are technically fluids, such as liquid'and gas, but -Fig. 4 is a vertical'seetion illustrating detail also solid substances of relatively small'size which of one embodiment of the time lock mechanism, Collectively e capable L OW' S mew at like Fig. 5 is a similar view illustrating details of ane a y the uid'which is trap n s10W- other embodiment of theinvention. I y r as d s s a ed 'pla y a av r fluid.

Similar reference numerals throughoutgthe h appa u t a edh y way fi xseveral views i i t t Same par1;s ample has'been designed to use a gas as .the a In Fig. 1 there is shown diagrammatically a 'lightel' fiu Which is t p and a iquid as door 11 of a safe'or vault, thedoor having bolts 12 the avi fluid which holds-it inxp mounted thereon, connected to each other by a viously other forms ofeapparatus may be made bar 13 which in turn is connected to a horizontal falling within the spirit of this invention; Without bar 14. The bar 14 thus forms part of theboltnecessarily u g a-liquid to seal a t work of the safe and, as it controls the movements j The present apparatus has also been designed of the bolts 12, the member 14 may itself be deto useordinary air as the gasiwhich istrapped, 5 scribed broadly as abolt. I and mercury as the liquid which sealsthe gas,

A handle spindle 15 passing through the safe but these features likewise, while they are'predoor 11 is provided with a handle 16 on the exteferred in the present instance, are not to be conriorlof the door, and with an arm 17 on the intesidered controlling and. may be discarded, withr ot. oi e d e 1 Th m i s a lot; is ;.out departing from the spirit of'theinventions)" suitable sealing liquid, such as mercury. At the top of the receptacle there is provided an aperture 28 through which a stem 29 extends loosely. To the lower end oflthisstemsinside the receptacle 25 there is fixed a.-chamber, 3.0 which may be described in general as inverted cup like,

or of an inverted cup shape. As will be clearly seen from the drawings, the-chamber30'has a substantially flat top through which wthe stem 29 extends and to which it is secured with an air ctightconnection. .The sidewalls of the chamber ;-are:prferably substantially cylindrical and of such size sand.- so .positioned that. they may move -=J.1p andidownifreely in the annular space 2'7 above 'ldeSCIibBd. ilThe cross sectional shape of the chamber as cut by a substantially horizontal plane may: be circular, oval; rectangular, or of any other {form .desired.

. zErom'the .parts'thus far .describedit -will*be lreadilymnderstoodthat air or any other suit- 'ablesgaszmayenterithereceptacle 25 through the raperturer28, since the stem 29 passes loosely :through .it -.:without a tight fit. Whenever the rchamberJBO iszraisedato such a position that the l'lowerledge 31.thereof isabove the liquid level 32 of the mercury or-other sealing "liquid =employe'd; then airror other fluid may'enter and Jflll thezint'erior of the-chamber 30. Then-if the --achamber :be "dropped slightly downwardly until "Iheilower edge 31 thereof 1 is slightly immersed tin :the :sealing "liquid, the fluid trapped in the mhamber will be sealed --therein and -cannot"es ,:-'slightldownward movement of "the-chamber '30 amayrtakeplace until the trapped fluid is --com- :pressed :to'i'an extent suflicient to equalize -the .zpressure caused I-by ;.the weight of the chamber :30 and parts .ssupported thereby, but when the seqmlibriumis reached it is obvious thatnofur- .ther downward -movement-of the chamber-can take :place i unless and 1 until some i of the trapped sage relatively slowly The porous material may fluid is released from the chamber.

Accordingtd-thepresent invention the trapped fluid is relea'sed at r a predetermined rate, so that after the above mentioned point of equilibrium hasibeen-reached thechamber 30fstem '29, and a-associated parts maycontinue to settledown- -ward'ly at a 'defiriite predetermined rate depending upon the rapidity with which the trapped fluid escapes. Mechanismds provided-so that as thing as the chamber'BO is at or --abovea predeter- -mined position -themember 14 of theboltwork .-c'annot be movedtdunlocking position, but as :=soon:'as the chamber30 reaches or drop'sbelow the predetermined position, then-the boltwork is re'leased and maybeiunlocked. Hence, it folilowsithat-a'fter the"chamber' 30 has'been charged with trapped fluid and released so that it may tbeginitodescendthe boltwork 14 remains' locked for a predetermined time interval. Thistime interval is -the length o'ftime necessary for a sufficient amountofithe trapped fluid to escape from *the chamber 30 so that the chamber moves downwardlym the predetermined unlocking position. Thus this mechanism may I be: described fluid controlled means for keeping the bolt in locked position for a predetermined time interval.

Preferably the means for releasing the trapped fluid from the chamber is adjustable so that the rate at which the fluid escapes may be varied, and thus the time interval during which the time lock is efiective may likewise be adjusted or varied. vIn this --,way the-@mechanism may be set .to-be. effectivejforla period of from afewmoments up to several hours, as desired.

:The fluid releasing means in its preferred form comprises a passageway 35 (Fig. 4) in the stem '-29-communicating at its lower end with the interior of the'chamber 30; The fluid escaping 1from -theg-chamber flows upwardly through this passageway toanvenlargement 36, and thence out through a. lateral vent 37. The stem 29 is hollow-fromthe enlargement 36 on up to its top, .andds threaded as indicated at 38. A member 39 threaded to cooperate with the threads 38 car- :riesra "needlewalve at its lower J end, :which :controlsithe flowrof fluid through thelpassageway '35. Byl means of :a long: screw. driver insertedlin thehollow-stm29fthrough its top and engaging the usual. screw slot 1 in the .top of the member .1539, theilatter may I'belturned to adjust it upor down andthus to adjust :theneedle'valve 40 to permit fluid to bereleased .through the-passageway-35 M any desired rate.

.Another possible embodiment of meansfor-congg 1 trolling therelease of: the fluid employs a porous plugas illustrated in Fig. 5. Here the' stem 29a has a somewhat larger passageway- 35a communicating with the interior of the-ChamberBO, and

leading-"to. an-enlargement 3fia in 'the stem, whichenlargement communicates with avent" 37a passing through 1 the wall of the stem. -*A shoulder 542 is formed at the junction ofthe passageway =3'5wwiththe enlargement 36a, and a porous plug is seated-on 'this=shoulder, a gasket43 preferably beinginterposed-between the plug and the shoulder so:as -to"form a perfectly air=tight joint. capeiiinw.the way in which it-entered. Some The i porous pl'ug may comprise, for example,

*any suitable substance 44 having more or less poro'sity so that flui'd can-=esoape therethrough,

which substanceis preferably surrounded by a sleeve 45 of metal or other suitable material.

' Numerous porous materials --are known and may be used satisfactorily, some of such materials permitting passage of fluid therethrough relatively rapidly; and others-permitting such pasbe either a naturally occurringip'orous :mineral,

' such for example as silicon, or an' artificially made productsuch for example as porous plaster, or

any other suitable product-"or material. When it"is desired "to varythe length 'of time during whi'ch this time' lock mechanism-is effective the porous plug may be removed and replaced -by another poro'usplug of a di'fierent material, or

of a diiTerentlengthof the same "material.

\ T0 1 make the porous plug readily removable and replaceable, the stem 2 9a is made'hollow all the way 'from the-shoulder'42'to'the top o'f the 5 Stem, and ofa sufficient diameter sothat th'porous plug may be inserted-and removed through the top of the stem. After inserting a plug, ac'oil spring-46 may be placed on-the -topof theplug and aplug 47 may then be-screwed into-the top of the stem 29a, to place the spring 46 under In the 'form of the invention illustrated in Figs. 3 and 4, the top o'f thestem' '29 is provided door 11.

' with a relatively wide laterally extending flange 50, with which the operating means cooperates as hereafter. described. In the porous plug form of invention illustrated in Fig. 5, a similar flange 5011 may be formed either as a part of the stem ber 56, which rests loosely upon the flange 50.

When this blocking member is in an elevated position, as illustrated in Figs. 2. and 3, it lies in member 56 drops'downwardly, however, to a position such as illustrated in Fig. 1, then it no ,longer interferes with movement of the lug 57,

and bolt member 14 may then be moved 1eftwardly to an unlocking position so far as this blocking member is concerned.

It will be seen that if the stem 29 be raised her 30 and the blocking member 56'with it, so

that the blocking memberwill be substantially in the position shown in Figs. 2 and 3, and will prevent unlocking of the boltwork. Likewise the chamber 30:will be substantially in the position shown in Fig.3, so that it. will become fllledwith Now if the stem 29 is released, the chamber 30, stem 29, and locking member56 will settle downwardly, but the downward movement will be relatively slow, depending upon and controlled by the rate of escape of the fluid trapped within the chamber 30. As the chamber, the stem,-and the blocking member descend,'the boltwork of the safe will be prevented from being unlocked so long as the top of the blocking member 56 is above the bottom of the lug 5'7, and not until the top of the blocking member drops below the bottom of the lug,-willithe' boltwork of the safe be released for unlocking. i

It is to -be especially noted that the blocking member 56is not rigidly connected tothe stem 29, but is loosely. connected thereto, preferably simply resting on top of the stem. This is advantageousbecause if it beattempted to move the boltwork prematurely so" as to press the lug 57 against the blocking member 56, this will not strain or injure the. time lock mechanism in any way or prevent it from fiuictioning, but will simply tend to tilt the blocking member 56 and will hold it rigidly in its guide 55, while the stem 29 will drop away from thebottom of the blocking member and continue to descend. As soon as the pressure of the lug 57 against the blocking'member56 is removed, the blocking member will drop downwardly in its guide until it again rests on the top of the stem 29.

' the combination lock 20. to itsuppermost position, it will carry the chamsuccessive oscillationso'f the lever.

when the blocking member j 56 rests upon the stem. Thus the .time lock mechanism cannotbe circumvented from the outside of the; safe, but on the contrary; when a premature attempt to unlock the boltwork is made,'the time lock mechanism will run still more slowly rather than faster, and the person attempting to unlock the boltwork prematurely will have 'a still longer time toiwait' until the boltwork can be unlocked.

Various means may beemployed for initially setting or starting the operation of the time lock mechanism. In the present instance it is found convenient to do this by means of a lever 60 pivoted at an'intermediate point 61, and having one end 62 in position to underlie the flange 50 on the stem-29; This end 62 of the lever is made thicker and sufliciently heavier than the opposite- The opfulcrum 61, lies in the path of movement of a pin 63 fixed to the disk 22 on the spindle 21 of Whenever the spindle 21 is turned to operate'th'e combinationlock, the pin 63 will come into contact with the righthand end of the lever 60 and will depress this end to the'po'sition shown in Fig. 2, so that the left hand end 62 is raised, and through contact with the flange 50 it raises the stem 29, the fluid trapping chamber 30, and the blocking member 56.

A part of the lever 601s curvedto conform to the arc in which the pin- 63 moves,'as indicated at64, so thatduring a substantial part of the movement of this pin the 'lever willbe maintainedin its maximum elevated position shown in Fig.2. Thus the wear onthe lever, caused by locked position, with the bolt 23 withdrawn, the I pin 'isnear the top of the disk and does not interfere with the return movement of the lever 60 to the'normal position shown in Figs. land 3.

In operation, when the sate is locked, the parts are in the'normal position shown in Fig. 1 with -the boltwork held from being unlocked by the bolt 23 of the combination lock, and with the blockingmember 56 depressed to unlocked position. When it is desired to unlock the safe, the combination lock is operated to withdraw the bolt '23. Each revolution-of the disk 22 in effecting such operation of the combination lock oscillates the lever 60 and the first such oscillation raises stem' 29; chamber 30, and the blocking member "56 "to the-position shown in Fig. 2.

f During subsequent revolutions of 1 the stem 21,

the lever 60 will again be'oscillateds'o that stem 29 and chamber. 30 are brought back to their initial elevated position at each "revolution of the spindle 21,; although-some slight settling of the chamberand stem may take place between The last revolution of thecombii ration spindle 21;inopcrating the combination lock, once more elevates the chamber =30 to its initial'position, andthen releases "it for its downward movement. 'The final motion of the combination spindle in withdrawing the combination bolt 23 from the position shown in Figs. 1 and-2"to the-positionshown in'FigJ-B wilLleavethe pin :63- 'in'an "elevated poposition shown 'in Fig. 3.

sition out of contact :with thetlever 60, soithat this lever may drop by gravity to the position shown Eig. 3,and..will remain there, permitting the chamber 30,, stem 29, and. blockingmember56 to descend in accordance withzthe. escape of fluidfrom" the chamber.

At this timezthe parts are substantially in the The boltwork. of the safe is no'longer obstructed by' the bolt-'23 of the combination look, but; it'is obstructed by the blocking member 56, sothat the safe. cannot be opened. The blocking member moves downwardly together with the stem 29 .and the chamber, in accordancewith. the release of fluid from the chamber, one intermediate position of the parts being illustrated in dotted. lines inFig. .3.

.At the end of the predetermined time interval, the-length of which is determinedby the, rate of escape of fluid from .the chamber. 30, the parts will have settled .sufiiciently so that'the. top of the blockingmember'56 isbelowthe bottom of the lug 57, and no longer obstructs the boltwork. The handle 16 onthe exterior of the safe may then be oscillated to move the boltwork member-14 and the bolts12j leftwardly to unlock the safe.

)Thetime lock mechanism has beenrdescribed as setin operation by the combination look, so as to delay theopening of the safefor a predeterminedlength ,of time after the combination lock isoperated. While;the time lock mechanism is well-adapted for use inthis connection it should be clearly understood that it is capable also ofmany other uses, and is not limited inits application to operation by acombination lock. The time lock mechanism mayflbe'setiinto operation, for example, by-operation of any form of lock other than a combination lock, such as an ordinary key lock, or operation ofthe timelock may beactuated by any other suitable'means or devices not connected with. or .dependent upon a lock of any kind. The time lock mechanism may also bearranged itgdesired, to be set into operation at the timethe-safe is locked, so as to prevent it from being openeduntil apredetermined length of-time:has.-elapsed after it was last locked. i

As an additional safeguardto preventthe time look from being circumvented, means is provided for retaining the sealing liquid inthe receptacle even if the safeiis tipped on;itsside or upside down, as might'be done in the case :of a small safe. Such sealing means preferably comprises a battle member 70 within the receptacle arranged so that even if the receptacle be turnedon its sideor inverted, the liquid sealing means is kept away from the aperture 28 and cannot flow out through the aperture.

:This-bafile, member 70,-. as clearly shown in Fig. 3,;may;be;.inthe form of a cup shaped member of slightlylarger'size than the chamber 30,fixed securelyi-by a liquid-tight 'joint to the top of the receptacle 25 in *such, position that the chamber .30 may flt inside the bafile when elevated to its .upper position. Theoavity within the receptacle '25 is,enlarged at ll-around'the bafile 70 to provide a-cavityof substantial size which will hold the sealing liquid. 'Henoe, ,if the receptacle 25 be turned on its side, or upside down, the sealing liquid will'run intothe=cavity 71 around the outside of the bafiie '70, and is-thus held away from theaperture 28, so that it cannot escape through the aperture.

Whilethe receptacleis on its side orinits upside ;d0.w.n position, the time, lockmech nism .Will

' not operate because it "dependsmpon gravity for its operation. As soon-.as'the receptacle is turned back to its normal .uprightposition,thesealing liquid. which has been held from escape -bythe baffle '70will run back to itsnormal position in the cavity 27, so that it:will properly seal the fluid within the chamber 30, and the time'lock mechanism will function: in the proper manner.

Usually thespace between the .stem 29 and the sides of the aperture. 28 issuificientto admitthe required quantity of gas to be trapped within the chamber 30. .If this space. shouldproveinsufficient for that purpose, however, a vent 75 may be provided for admittinggas more rapidly to the receptacle 25 when'the chamber 30 is elevated.

.A strainer comprising.porous.material '76, such as cotton or the like, may be held inplace by. a cap 77 over the vent "75, sothat any gas entering through this vent is strained and foreign matter is prevented. from entering with it. Furthermore if the receptacle is placed onits side.or upside down temporarily, the strainer 76 will prevent the sealing liquid from running outthroughi the vent.

Preferably the closure 26 of the receptacle25 is sealed in such manner that itcannot be removedsurreptitiouslyfor.the purpose of extracting all or a part of the sealing liquid from the receptacle. This mayconveniently be .accomplished byholding theclosure 26 inzplace by lughave been disclosed, it is to beunderstood that the inventive idea may be carried out in anumber of ways; This application is therefore not to be limited to the precise detailsdescribed, but 'is'intended to cover all variations and modifications thereof falling within the spirit of the invention or'the scope of the appendedclaims.

I claim:

1. Locking .mechanism .for safescomprising means for controllingmovement of abolt, said means comprising a chamber enclosing a quantity offluid, anda porousmember through'which fluid may escape :from said chamber.

2. Locking mechanism for safes comprising means for controlling, movement "of .a bolt,.said means .comprising a chamber. enclosing a .quan- .tity of fluid, a passageway through whioh'the enclosed fluid may be released, and a porous member in said passageway vfor:controlling the release of fluid therethrough.

3. Locking mechanism for safes. comprising means for controlling movement of a bolt, said means comprising a'chamber enclosinga quantity of fluid, a passageway through which the enclosed fluid may be released, a seatassociated with said passageway,-a porous member mounted on, said seat for controlling the release of fluid through said passageway, and resilient means for holding said porous member in cooperative .rela- 'tion to said seat.

4. Locking mechanism for safes comprising means for controlling movement of a .bolt,.said

means comprising a chamber enclosing .a quantity of fluidzand porous means lforycontrolling release of fluid from said chamber at a predetermined rate.

5. Locking mechanism for safes comprising means for controlling movement of a bolt, said means comprising a chamber enclosing a quantity of relatively light fluid, a heavier fluid for sealing the relatively light fluid in said chamber, and means for releasing the enclosed light fluid from said chamber.

6. Locking mechanism for safes comprising means for controlling movement of a bolt, said means comprising an inverted cup like chamber for trapping a relatively light fluid, a heavier fluid in which the lower edge of said chamber is immersed to seal said relatively light fluid in said chamber, and means for releasing said relatively light fluid from said chamber.

7. Locking mechanism for safes comprising means for controlling movement of a bolt, said means comprising an inverted cup like chamber for trapping a quantity of gas, a body of liquid in which the lower edge of said chamber is immersed to seal said gas in said chamber, and

means for releasing said gas relatively slowly from said chamber.

8. Locking mechanism for safes comprising means for controlling movement of a bolt, said means comprising an inverted cup like chamber for trapping a quantity of gas, a body of liquid, means for raising the lower edge of said chamber above said liquid to admit gas to said chamber and for immersing the lower edge of said chamber in said liquid to seal the gas in the chamber, and means for releasing the gas from the chamber.

9. Locking mechanism for safes comprising a movable member, an inverted cup like chamber for trapping a quantity of gas, a body of liquid in which the lower edge of said chamber is immersed to seal the trapped gas therein, means for releasing gas from said chamber so that the chamber may settle into said liquid, and a blocking member controlled by said chamber for blocking movement of said movable member until said chamber has settled to a predetermined position.

10. Locking mechanism comprising a bolt, a lock for preventing unlocking movement of said bolt, an inverted cup like chamber, a body of liquid associated with said chamber, means effective upon actuation of said lock to trap a quantity of gas in said chamber and to immerse the lower edge of said chamber in said liquid to seal the trapped gas therein, means for releasing gas from said chamber so that the chamber may settle into said liquid, and a blocking-member controlled by said chamber for blocking unlocking movement of said bolt until saidchamber has settled to a predetermined position.

11. Looking mechanism comprising a movable member, an inverted cup like chamber for trapping a quantity of gas, a body of liquid in which the lower edge of said chamber is immersed to seal the trapped gas therein, means for releasing gas from said chamber so that the chamber may settle into said liquid, a stem secured to said chamber to move therewith, and a blocking member cooperating with said stem and movable therewith for blocking movement of said movable memberuntil said chamberhas settled to a predetermined position, said blocking member resting loosely on said stem so that transverse pressure on said blocking member will not prevent movement of said stem and chamber. 12. Looking mechanism comprising a movable member, an inverted cup like chamber for trapping a quantity of gas, a body of liquid in which the lower edge of said chamber is immersed to seal the trapped gas therein, a stem secured to said chamber to move therewith, means within said stem for controlling release of gas from said chamber so that the chamber may settle into said liquid, and a blocking member associated with said stem and movable therewith for blocking movement of said movable member until said chamber has settled to a predetermined position.

13. Looking mechanism comprising a receptacle having an aperture in a wall thereof, a body of liquid within said receptacle, an inverted cup like chamber within said receptacle, said chamber being arranged to have the lower edge thereof immersed in said liquid to trap a quantity of gas, a stem attached to said chamber and passing loosely through said aperture, and means for preventing escape of said liquid through said aperture'when said'receptacle is inverted.-

14. Looking mechanism comprising a recepand a bafile wall for holding said liquid away from said aperture when said receptacle is inverted so that said liquid cannot escape through said aperture.

15. Locking mechanism comprising a receptacle, means within said receptacle for trapping a quantity of gas, a vent for admitting gas to said receptacle, gasstraining means associated with said vent, a bolt, and mechanism cooperating with said gas trapping means for holding said bolt against movement.

16. Locking mechanism comprising a bolt, a combination lock for preventing unlocking movement of said bolt, an inverted cup like chamber for trapping a quantity of gas, a body of liquid for sealing the trapped gas in said chamber,

means for releasing gas from said chamber so that the chamber may settle into said liquid, mechanism controlled by said chamber for preventing unlocking movement of said bolt until said chamber has settled to a predetermined position, and means effective upon actuation of said combination lock to raise said chamber until the lower edge thereof is above said body of "liquid in order to admit gas to said chamber and to release said chamber so that it may settle into said liquid in accordance with the release of gas from the chamber.

GERRIT D. HILL.

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