US2827669A

US2827669A - Silos

Info

Publication number: US2827669A
Application number: US118076A
Authority: US
Inventors: Raymond E Barden
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-09-27
Filing date: 1949-09-27
Publication date: 1958-03-25
Anticipated expiration: 1975-03-25

Description

March 25, 1958 R. E. BARDEN SILOS e Sheets-Sheet 1 Filed Sept. 27. 1949 INVENTOR.

a ih HM-UHI-IU--- March 25, 1958 R. E. BARDEN 2,827,569

SILOS Filed Sept. 27, 1949 6 Sheets-Sheet 2 ggggw INVENTOR. Paymona/ L Bare/en March 25, 1958 R. E. BARDEN SILOS Filed Sept. 27, 1949 6 Sheets-Sheet 4 X 0 b 8 2 b 5 o b 2 7 U 3 5 w l M 3 I 3 a, 6 3 u a 7 3 a o 5 97 a 8 Z u a 7 2 I: -&A

WJ m L. J w m 7 WW R M R. E. BARDEN SILOS March 25, 1958 6 Sheets-Sheet 5 Filed Sept. 27. 1949 k W 7 me mm Na 3 E w mw v a F m a mm 9% w W M I WW March 25, 1958 R; E. BARDEN 2,827,659

, SILOS Filed Sept. 27. 1949 6 Sheets-Sheet 6 INVENTOR.- I Paym ohc/ 1 Burden (TI- g k m f United States Patent SILOS Raymond E. Bar-den, Holcomb, N. Y.

Application September 27, 1949, Serial No. 118,076

6 Claims. (Cl. 2(l1.4)

The object of this invention is to make a new and improved silo.

Another object of the invention is to provide a new and improved means for anchoring the silo to the foundation.

Another object of the invention is to tie the upright staves of the silo together with an improved form of dowel pin.

Another object of the invention is to use hoops made in two sections and join the rear ends of the hoop sections together with a new and improved form of coupling bracket and make the ends of the hoop sections conform to the bracket.

Another object of the invention is to shape these coupling sections and arrange them in a column so that they serve as a ladder from the bottom to the top of the silo, which ladder should reach to the filling opening at the top of the silo.

Another object of the invention is to provide means by which the staves and door posts are tightened up without decreasing the diameter of the silo, but increasing the width of the door opening and also provide means by which the door itself can close the increased opening.

Another object of the invention is to join the front ends of the hoop sections together with a turn buckle with which the hoop sections can draw the staves and door posts up to a predetermined diameter. 7

Another object of the invention is to build the silo on a concrete foundation, the diameter of which does not change as the silo gets older and build the silo in such manner that the diameter of the silo is from bottom up kept uniform as the silo gets older and keeps a uniform fit with the foundation.

Another object of the invention is to provide drainage between the bottom of the upright staves and the concrete foundation on which the staves rest.

Another object of the invention is to connect the bottom of the staves and the top of the foundation so that the staves will resist an inward thrust.

Another object of the invention is to provide a door that will take up or close any increase in the door opening.

Another object of the invention is to support each door on two upright pivoted links which permit the door to swing in and up to open the discharge chute of the silo.

Another object of the invention is to connect these upright links together with angle irons or cross bars so that a ladder is formed thereby.

Another object of the invention is to make each door wider than the discharge opening, forming each door with a beveled edge that rests against and overlaps a corresponding beveled edge formed in the upright door posts.

Another object of the invention is to clamp the top of the staves together in a circle and hold them in line with each other with an inverted channel shaped member formed on the upper ends of the staves in which channel shaped member the ends of the staves are loosely held together so that they can slide in the channel and which channel shaped member is at suitable intervals attached to one of the upright staves.

ice

Another object of the invention is to form the dome or roof of the silo in four sections, each of which is supported on a horizontal laminated member that rests on the inverted channel and fastened thereto by suitable upright lengths which four roof sections are suitably joined together on radial seams, and are fastened to the laminated sections by metal brackets.

These and other objects of the invention will be illustrated in the drawings, described in the specification and pointed out in the claims at the end thereof.

In the drawings:

Figure l is a side elevation of the silo With a large section taken out near the top of the figure.

Figure 2 is a detail view of the dowel pin used for joining the staves together.

Figure 3 is a horizontal section showing two staves held together by the dowel pin.

Figure 4 is a vertical section showing how the tops of the staves are joined together in a circle and how they support the roof.

Figure 5 is an upright section on the line 5x, 5x of Figure 6 showing the bracket by which the upright staves are joined to the concrete foundation.

Figure 6 is a front elevation of the bracket and staves shown in combination in Figure 5.

Figure 7 is a front elevation of the door opening and the foundation of the silo, two of the lowest doors and a part of the third door being shown.

Figure 8 is a horizontal section on the line 8x, 8x of Figure 1 looking at it from the right hand side of Figure l, the chute being shown partly broken away and the door posts being shown in their original position; namely, closest together with the opening between them, which opening is closed by the door in its normal or closed position.

Figure 8a is a detail vew of the turn buckle.

Figure 9 is a horizontal section on the same line 8x, 8x of Figure 1, showing the door posts drawn apart by the hoops and nuts thus enlarging the opening with the doors in their normal position still closing the enlarged opening.

Figurev 10 is a diagrammatic view showing the doors and the links for supporting them in side elevation looking.

to the left from the section line 10x, 10x of Figure 8 with the intervening portion of the silo structure omitted from the drawing.

Figure 11 shows the top and bottom horizontal angle irons that connect the upright links together, which links support the door; the details of the doors and supports therefore partially appear on the right of Figure 1 at the bottom, the upper doors etc. being concealed by the chute.

Figure 12 is a top plan view of the coupling that holds the rear ends of the hoops together, which couplings are shown on the left of Figure 1.

Figure 13 is a section taken on the line 13x, 13x of Figure 12.

Figure 14 is a top plan View of the roof, and the dormer windows.

Figure 15 shows an elevation of the dormer window on the left hand side of the roof of the silo looking at it from the left.

Figure 16 shows one of two sections of the roof looking at it from below.

Figure 17 is a section on the line 17x, 17x of Figure 14 showing how the four sections of the roof are bolted together from the outside.

In the several figures of the drawings, like reference numerals indicate like parts. I

In the drawings reference numeral 1 indicates the concrete foundation which foundation has a bottom 2 and an upright circular wall 3. The top of the circular wall is cut ed at an angle of forty-five degrees sloping down and V bothsthe uphightwallgandilreibottonnofitzhestaves'ismserlr: for thepurposeiotgivinggoodzdtiainagerbetweentthenpe right stavesxand theneoncretewallzso the stavesi berkepttasdny as. possible.

The bottomsrotthe staves rest: onithe heizelediedgeeof the concrete wall below the topznome'r hithe -concrete wall; so that.therconcreterwalleerves"as"a backing forthe ring of: staves. that is; erectedi'ondt; Eheniangularspane:

between the back-of. the staVesrand-I thetopiedge. oitlie wall can be filled in with any plastic material-es s'siindicatediby referencenume'ral 6;; These details in Figure 5, of the-drawings.

are all shown 7 -At tregula-r. intervals. a metak strap fl fastened: to two V or more of the upright staves. strap-.isaengagedby'i a=. bracket-8,;which' is perforated :at. the bottom. through which perforations extends. a stud or bolt. 4; stud:

connected to the bracket-3 by'the'nut19 so that the: stajves at regular intervals. are positively held {d -Qn :th foundation wall 3. V V a The staves ;are. joined together radially with a-;.tongue 4 25 ure 3. The staves are about tsixinches-widek The edges, v

and groove joint. as. shown :in. horizontal. sectionin Fig? ofithe staves are ;cut. .-radial tethe diameter of thesil so that when the staves are-joined together they form :a-...

circle Atregnlar intervals-item top to bottorm; the staves are: 'joined: together .cireumferent-ially by ;-metaldowel pins 10 suchaas are. shown :in Figures .2. .and;.-3..v

These: dowelpinsalso hold} the staves from working up andtdown' on eachnother; "Ihese dowel pins aaremacle'ofi metal and on each end-are formed with barbed cones,

Thetstavesare bored with hdleshayinga diameter that theytake a firrn hold thereon. These staves areassem bled in a ringuaround the silo'andare hel d .-in.plac.e in'a cylinder. by the hoops which together with'their' attachments encircle the-silo as will presently be described; Each of thesehoopscomprises two members 12a and12b-. At the rear endithe endsofithese members'are swedged up as ihdicatedhat. 13a=and 13b. These rmernb erzs rare joined together by: a ..rectangular coupling :15 shown ill! Figure 12.1 The end :Wallsof this coupling are perforatedas indicatedat 16 .so that the members 12a.and .I-ZbKea-n.

be passed through the openings in the endwallsfof -the couplings. .The.:membens-.12a .and lib-are then'drawn into theupper. slot shown-in Figure .13- and the s-Wedged end isYjamrne'd, into the hole Shy. which it .is firmly: held in place. i

One. side. "I 7 fo'fthe coupling isfformedlto-one radius andtheother .side 18 'is formedto another radius, :the

ideabe'ing thatone side 17 is appliedito the..silo having a radius of seven feet, and the otherside 18heingapplied .to a... silothaving, a. radius of six feet, onanyother radius'that'niightbe used in standard construction coizrcsponds -:to the intermediate section .-11;.0f the dowel pin, and. when the dowel pins are driven intothe staves,

"buckle is less than the opening betweenthe, deer-posts H -2 '7a. and.27; z;%namely, abouttwentyfinches, 1

The .coupling in one instance. is applied .as shown:in

Figures 12'and 13' with'the side 17 against the silogand in the other instance is applied with the side -18 against the silogbut theiposition of thecouplingis then reversed.

The. dowels. 10 vans usedhto join. the-staves together-- both above and below the joints 21. If the silo is thirty feet high and the staves arestwelve feet and eighteen feet in length, there will be two rings of

joints

21 and 21a as is shown in Figure 1, and in such case there will be used at least five rings of dowel pins such as is shown in Figure 3 and there will be one .dowelpin in each ring for each stave. These rings of dowel pins will be located, substantially as follows. In a thi-ity foot silo the lowest ring will be about two feet. above. the foundation, the second ring will be about two feet below the ring '21inFigure 1, the third ring will betabout irnidway bfiLWECIlIhfii-

IillgSgOf joints

21 and 21a, the fourth vringwillwbe two feet above silo ib-y -a turn: Zbuc'kle zthat' willinow :be: described.- EEhisI turnbuckle .is:showneseparatelyiinz-EiguretSa;.

lnua .silo that fourteen feet. in: diameter, the total length of each hoop and couplings would be aboutrfizrtyfour feet. Theicoupling :Jjatfthe backwouldibe zahout one-foot long; and the; membersdZa ia'ndjz-Z-b would teach;

heia'hont twentyaone1-:(21=) :Eeetclong. About-eighteen ineheszofthe. .forwardtendofi :each get :these :two imemheis would be made of stock about one-eighthinchthick r than-the balance. of then-member. That is. toesay; :ifrthe member 'weeeema'cleu of sonerhelf inch pmund :SLQQK about.

eighteen;inches; ofironnd' :stock :five-eighths; inches lin di amnterawouldibe welded-ionztcntheend of:i.t*and this large end of eighteen inches would be threaded asshOwu-at;

25a and 25b iin- "Figures 18- 1and';9..' Th setthreadedqeud ZSauand 255 connected. by a turnbucklelfilzwhiszh' turnbucklerisseparatelyi shown in Figure 38:15am '.s {shown irrzcombinationxintFigures ,8;and;9;.. .Theenjds-ofthe turnbuckleengagethe threaded-ends 25a and 25bof thfismenig bersitlza 'and'i12b sand the tuisnbuekleis turned to, draw these.- members together; so that the :hoop -.a s a whole is drawn tightly: around thestaves.

It will also be understood that;one 10f the: leads will bfirfi right-hand thread and tthe other will tbea lefgthand thread-sotha-t; the two members-will tbe-idrawn Qgethenas thezturnbuckleisturned. V

;.It willzalsohe understoodtthat -the;t;urnbuckle:is located inwfront of; the doonopening andthe length of-the..-turn men; the threads .2511 and 25b nuts ,28.a,;a,nd are placed, which when turne dtdrawihe postsfirmly against the stavestand tendsttoenlaggeathe;door opening-and -zas the-turnbuckle 2.6 .is turned, itetends to close lthe" door opening andmake ,a stable ist ructure' of the desired-diametere door or -one tdool fort every} hoop;t that. encircles ..the. silo XP 1 Q h s-P- -1; t w :is s ow 9? plan view in Figures 8 and 9;; Qumach .door thetqare two .-cleats. .3 6a.and 36b. .Bivotallymounted on .Fthe'hubs of.the-..tui nbuclile arej-thelinks37a andzfi'lb. Each of V thesel links is C -shaped and has egesfisa and (38b) at the top where they engage the hubs of the turnbuckle.

They .extendoutwardlylfmmthe doonways as; indicated-at It will understood that there, is one hoop ,for every long. When each door is closed it rests directly on the door below it, making a tight fit with the lower door. For this purpose each door is cut away to make a ship lap joint as indicated at 45 in Figure 10. The

eyes

38a and 38b of each link are pivoted on the hubs of the turnbuckle and the turnbuckle is supported on the threaded end of the hoop.

It will be assumed that the door is about two feet high and the ensilage will be removed from back of the door as far down as may be necessary. The top of the door will be swung backward around the bottom of the door as a center carrying with it the lower ends 42a and 42b of the links. The lower ends 42a and 42b of the links will travel up slightly in the slots 43a and 43b. When the top of the door gets back far enough, the door can be moved up endwise and the middle of the door and the bottom of the links will then swing in a circle of which the hub of the turnbuckle is the center and the door can then be placed in the horizontal position indicated by dotted lines in Figure 10, and from there it can be swung to the upright upside down position shown by dotted lines at the top of Figure 10. In Figure the top door is shown in dotted lines in an inverted position. Fastened to the frame of the dormer roof 'at the top of the chute on the right of Figure 1 is a hook 47 which engages the top door and holds it up in the dotted line position shown in Figure 10.

On the top door shown in full lines in Figure 10 is a hook 43. When this door is swung up to its dotted line inverted position, this hook 48 will engage with the next door below it when it is swung up to the inverted position. The next door below it is indicated at 35 and is engaged at the top with the hook 48, after it has been swung up to the broken line position shown in Figure 10. In like manner each door will be swung up to this position as the ensilage is removed from the silo, and the level of the ensilage falls to correspond.

As will be seen in Figures 8 and 9, the top of the door is shown in both figures in solid lines and the back of the door 35 is much wider than the front of the door and the side edges of the doors are beveled and the backs of the door posts 27a and 27b are beveled to nearly correspond and the outer edges of the beveled sides of the door rest against the beveled backs of the door posts and make a close fit therewith, whether the door posts are closer together as shown in Figure 8 or are spread apart as is shown in Figure 9.

To secure this result the bevels on the door are made slightly out of line with the bevels on the door posts.

, It will thus be seen that the doors rest closely against the door posts and will securely close the door opening or doorway at the front of the silo regardless of whether the position of the door post has been altered much or little.

It will also be understood that an ordinary turnbuckle has two hubs rigidly connected together by two sides of links which enclose a rectangular space between. But the turnbuckle that I use, which is shown in Figures 8, 8a and 9 omits one of these sides or links. The turnbuckle is made in this way, so that it will not obstruct the cleats on the doors as the doors move to their outermost position as is shown in Figure 9. It will be assumed that the clearance between the inside of the hubs of the turnbuckle is about fourteen inches and the threaded ends of the hoops project into this space an inch or so as shown in Figures 8 and 9. The cleats will be placed on each door so that when the door is in its outermost position radially as shown in Figure 9, these cleats can extend into the open space between the threaded ends of the hoops, which threaded ends may be less than ten an-1 ar all), i rasteu the angle irons As shown in Figures 1 and 8 and 9, I provide a chute 53 on one side of the silo. This chute encloses the doors shown in Figures 8 and 9 so that, if the wind blows, the ensilage will fall straight down in a pile. This chute is fastened to hoops 12a and 12b by brackets 54a and 54b,

' which brackets consists of a metal strap that goes around the hoop and the two ends are brought together and given aquartcr turn, which can then be bolted to the frame of the chute.

It will also be understood that after the siio has been built some years, the staves will shrink and it will then be necessary to turn the nuts 28a and 281; so as to spread the door posts 27a and 27b apart and take up the shrinkage and tighten up the staves against the hoops. In this way the silo will be heldto substantially the same diameter throughout and will always fit the base and the roof will always fit the top.

In Figure 4 the tops of the staves 5 are shown. After the silo has been finished up to the point an inverted channel 60 is built on top of the staves clear around the silo in a complete circle. Where this channel encloses the tops of the door posts, the tops of the door posts are cut away to conform to the thickness of the staves. This channel is made up of five members, one member on the inside about one inch thick and eight inches high or wide. Next is placed two intermediate members, each about one inch thick and about four inches high and on the outside two members eight inches high or wide are placed each about one inch thick. These members are all shown in cross section in Figure 4 and are bolted together by a series of bolts 65. At suitable intervals straps 66 are used which are pivoted on the bolts 65 and bolted to the staves at 67. These straps as are 'morticed into the inside of the channel, the mortice being wider than the straps 66. This construction permits the tops of the staves to move sideways in the channel.

The roof of the silo and its sill rests on this channel and is attached to it. The construction of the roof and its sill will now be described.

As shown in Figures 1 and 14 the roof 7% of the silo is substantially a dome or a half of a sphere. it is made up in four

sections

71, 72, 73 and 74-. These sections are preferably interchangeable. The section 72 has a dormer roof 72a built therein to cover the top of the chute 53. The section 74 has a dormer window 74a built therein to provide for a filling opening. This dormer has a roof 75 made in two sections 75a and 7522 which are symmetrically alike. These sections are hinged on the side at 76a and 76b. Each section of the dormer roof can swing on its hinge outward as shown in dotted lines near the top of Figure 15. This uncovers an opening near the top of the dome through which the silo can be filled from above instead of from the side. This allows easy filling of the dome of the silo giving greater capacity. The two halves of the roof of the dormer will be closed with an overlapping joint. Each of these four sections of the roof is built in the shop or factory and each section includes a sill 89 and

rafters

81 and 82. These rafters are joined together at the top by a corner bracket 83 as appears at the bottom of Figure 16.

Each section of the roof is covered with a metal plate 84, which plate on the edges of the section is first bent up and then down on itself so as to form a flange 85' outside of the roof and an angle 86 inside of the roof in which angle the

wooden rafter

81 or 82. is fastened. When the sections are brought together the flanges 35 outside of the roof will lie side by side and will be covered with a metal channel 87. Through this channel and the flanges, bolts will be drawn which will draw the channel and the flanges close together and make a rigid leak proof construction. When the sections of the roof are ready to be assembled on top of the silo, metal straps 88 will be used to join the sills 863 to the channel 60. The sill will preferably be made of several laminations which will extend preferably up and down, and the 7 h pu pla e ne th itopi llfihilQ- af ers i i b amina ed hl anner i l ih he e t re the mi a e s illpr fere he'h ehte Thelsill is ast h d h e' ef sec ion by h aeh ts 8&4? V

Figuref l.

It will also beunderstooglthat suitable cQnstt'uetion of t rafte s will beextended up fron lthelsillto support-the dormer window 744, V s

' It will also be understood that a suitable sill 9,0 in -1 dicated by dotted lines in Figure 14 isformed on the under sid e of thedormer roof7 2q to fit the top of the chute 53 andthe dormer roof 72a will be Welded to the roof of. the section.72. h t a V A hole 91 is provided atlthe top which can be coyerecl "with any suitable forns of ventilator. A ladder 94 will section 74 having the filling dormer window, can-he located'inanyof the three remaining places. 7

Having thus described the details of thecpnstrugtion,

I will e e e e ess mhl hs of, the .silqh he 1119"? general way.

' First the foundation is laid with studs 4 flset upright ther in- Th o pests e hth t ee l h -ih a thi y foot silo will be erected in place oh the fgundationfand held in place by any suitable falsework. Ihestayes will then be assembled on the foundation. Ihe fi st stave will be fastened tothe door post by the dowel pins 10 shown in Figure2. VOther staves will be a' d'oontinuously, around the ring of the foundation from each b Pe a d the laves h t me at the heiehi il h sprung together and locked with the dowel pins; as they are sprung. The staves willjhe erected to the tul height as the structure progresses-mound the .silo and the s tay, es are locked with the dowel pins. At the bottom the stayes will be held in position by the first hoopwhichwill he placed about six inches above the bottom of the stage.

All of the hoops will be bent in the shop to the tight.

eurv A te a ew s t s h ve. been e e t d I n hh side of the doo rpos t, a s'econd ho p will be put in place abou on half wayhp t tsi o e t ce h h t plaeeatqrhearthe baqkwit ehi ork- "As th ass mb .e th is eves .n hl te te Jt e d lpi hQ the states in, PlQ Q Q K Ql PX e purposes and then therernainingthoop 's and couplings and h n he le a eph -Q fo' h r hmhseze liei th c p tmctu e q ethe i will b h s o t tshitah et tle willhepbh esl n the d o p s o th i eeeptieh hfl h h Pf the hoops and h t hes ms and brack t t3 W 1 eh hh the bottom ofthe staves to the t ds i tth i a Wh n the .hQQBShh Pas e throu t e deer PQs s, the n 728 311. 23 (ar three s ht th end .f the hoops. V V i I wi s he hhd rstqedthe th lihkeihvi ehhd 5% wil be p ac an he hub q i h i lIQbJ Ekk eh ktli h hekl s will he eigagedlw ththe 19922 .th the-12h p of r w n thehebheih oh aeea a h doors w thehi h ihhhgf mm the ihR 'ah Qthe in s l b ied ,ths b the A l h h 1 l m' the steps or rungs thelgdder. l

T e ann l wi l .en he hhilthh the 9f th sie an he seetiqhs 9 th -i lF Q9f "w ll h lli am e Q epto eth h hehheh V l "Th he t pleswh1l1h i-....ed; ,iht xs lst rt e anchor the hoops to the s tave s that'they -Zstay .iii' a horizontal line.

In FigureS I have shown the top of'the concrete base in said silothaving a hqepee t nd tht' h s Ma 9 U e esl et ah an e- M a d h hh m 9 he ves rehe eled hh st. o h e pehd hi a le" P t e base, may be of any greateror Iessanglle may be with alhoriz ont al step or a series of steps cutftherei 'n 0h which can rest the bottom of the stayes if 'the'yfare' a etri t a le at t bottom These. vt ht qns illi e sil hhd qtti. by hshe t qh f 895 5- 1h .e sil he-e mhih tihn of as and ri ht: te ellha ne H PQ QPPd n t e ieves and Pl Pe 'f he il togethenpsaid hoops hayihg threaded ends; a doorway ston each side thereof circuine enh .ve hthh f thee ht ste es h hq t' e oops eX hd h lrh g h S s 99 th n s on t e hre ed hes @Seidhows he ihlhn the a n s e fi idi po a rh e phpl hseth fre end -7. 5 id h h t aid Posts; hex o i h i h htihUYf mit? hher' ies h a s e tnamel es? aid dehrif i eeh of e em n w th slat i [th Sid o the 4 9 2 7: h ehit sa d ee may be ew i wa y a d p e' d y efeh up h n d-D si 611., ,e .hbhk' pq t 'ihe door in its iIlYCljtCd po 11. i i

3. In .a silo, th e e ation of va base and upright ie ps r oundin th st e and hqld e h together, said loops haying threaded ends a door" in said silo haying a posfon each ferentially abutting adj hd of Said h hh lhee h hhh ld'hh e hr f kle e p ine h fr e nds sa l h hav a single efifset en al o e t P 2W? 9: the .Q tsig e f ea h deer .snaeed j e h 2 in qf aeh f yi ieh ib y te lq. he mm lbH I Qth OI-heI w it h hh .ehhhl pa d es le hi e h h i' ef ifeei ed e by whi leh esem tth a s bmit 5. In a circular silo, a plurality of staves arranged in a C to form a door, tension means extending around said staves from opposite sides of said door, means for maintaining said staves in a fixed circle, and a rigid annular inverted roof-supporting channel positioned on the upper ends of said staves, with the inner and outer flanges closely embracing said staves, and articulated means vertically extending connecting said staves with said channel, whereby said staves may move circumferentially with respect to the channel.

6. A silo comprising, in combination, a base, upright staves, said staves forming a 'C-shaped wall providing a door opening, a post on each side of said door opening abutting the end staves of said 'G-shaped wall, hoops surrounding said staves and having threaded ends extending through said posts, nuts on said ends adapted to bear against the facing sides of said posts, a turn buckle joining said threaded ends, said turn buckle having threaded end portions, and a single connecting bar portion extending between said end portion and laterally disposed in respect to the threaded ends of said hoops, said posts having beveled inside faces extending over the circumferential thickness of said posts, and doors for said door opening having beveled edge faces adapted to engage said beveled post faces in a radial outward direction.

References Cited in the file of this patent UNITED STATES PATENTS 61,690 Shea Jan. 29, 1867 10 Repp Dec. 1, 1903 Walrath et al July 2, 1907 Van Cott Nov. 9, 1909 Naylor Oct. 25, 1910 Reese May 30, 1911 Horn July 9, 1912 Schlachter Oct. 29, 1912 Morrow Dec. 31, 1912 Rice July 29, 1913 Archer Jan. 19, 1915 Cavanaugh et a1 Mar. 14, 1916 Cronemeyer Mar. 6, 1917 Adams July 3, 1917 Greenwood Aug. 14, 1917 Pugh Apr. 30, 1918 Peterson Oct. 8, 1918 Van Cott Apr. 22, 1919 Jones et a1. July 6, 1920 Van Cott Dec. 13, 1921 Reinhart July 10, 1923 Kaatz Nov. 21, 1933 Rowell Mar. 31, 1936 Hanson Oct. 17, 1939 Cowin Jan. 16, 1940 Van Cott et al Dec. 16, 1941 Van Cott et a1. July 14, 1942 FOREIGN PATENTS Great Britain ..-of 1889