GB2332612A - Cage filter cap - Google Patents

Cage filter cap Download PDF

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Publication number
GB2332612A
GB2332612A GB9906360A GB9906360A GB2332612A GB 2332612 A GB2332612 A GB 2332612A GB 9906360 A GB9906360 A GB 9906360A GB 9906360 A GB9906360 A GB 9906360A GB 2332612 A GB2332612 A GB 2332612A
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Patent type
Prior art keywords
cage
filter
rack
member
top
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9906360A
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GB9906360D0 (en )
Inventor
George Gabriel
Chin Soo Park
John E Sheaffer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PRODUCTS LAB Inc
Lab Products Inc
Original Assignee
PRODUCTS LAB INC
Lab Products Inc
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters, i.e. particle separators or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/0039Filters, i.e. particle separators or filtering processes specially modified for separating dispersed particles from gases or vapours with flow guiding by feed or discharge devices
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01KANIMAL HUSBANDRY; CARE OF BIRDS, FISHES, INSECTS; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
    • A01K1/00Housing animals; Equipment therefor
    • A01K1/02Pigsties; Dog-kennels; Rabbit-hutches or the like
    • A01K1/03Housing for domestic or laboratory animals
    • A01K1/031Cages for laboratory animals; Cages for measuring metabolism of animals
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters, i.e. particle separators or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/10Particle separators, e.g. dust precipitators, using filter plates, sheets, or pads having plane surfaces, i.e. axial filtering
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2265/00Casings, housings or mounting for filters specially adapted for separating dispersed particles from gases or vapours
    • B01D2265/06Details of supporting structures for filtering material, e.g. cores

Abstract

A filter cap for an open-top cage comprises a substantially rigid bonnet 80 adapted to cover the open top of cage 60. The bonnet has a perforated top and side walls extending therefrom forming an open bottom. A rigid filter retainer 100 is provided sized to be coextensive with the perforated top of the bonnet. The filter retainer has a top with perforations coextensive with the perforations in the top of the bonnet. The filter retainer also has side walls 108 extending from the top end. Securement means for detachably securing the filter retainer to the bonnet are provided to permit enclosure of a sheet of filter material 99 between bonnet and retainer. The securement means is integrally formed in the bonnet and filter retainer.

Description

1 2332612 VENTILATED CAGEAND RkCK SYSTEM BACKGROUND OF THE ENVENTION This

invention reiates generally to ventilated cage and rack system. and more particularly to an open rack system which maximizes both cage density within the rack and useful volume within each cage while providing protection for both personnel attending to the svstem and animals contained within rItie caL7es from contamination.

Ve-,ATIlated cage and rack, systems are weil known in the art. One such ventilated cage and rack system, is disclosed in U.S. Patent No. -1.989, 545, assigned to Lab Products. Inc.. M which an open rack system including a plurality of shelves. each formed as an air plenum, s provided. Air ventilation is provided directly to aninials within each cage by allowing air -,o:ravei within each sheif to a piuraiit-,- of predeternruned positions within the rack. At least one cage level barrier having a filter bonnet is positioned on a shelf so that the shelf removes air disposed adjacent the bonnet. A cage --uide is formed in substaritially the same shape as the bonnet and is affixed to the bortorn of the shelf so that when the barrier cage is placed within the ventilated rack. it is positioned within the cage -guide. The cage guide is separated from the bonnet by a relatively small distance. The air Dienum shelf is provided with a negarive pressure to remove zases &om above the cace bonnet.

n Ine prior an ventilated cage and rack systenn was satisfactory. However because zo each shelf acted as an air plenum. each sheif required a cern height within the rack to allow for air to travel therethrouah. Accordingly, the combined height of each shelf and the cage guides mounted beiow each sheff limited the.,e-.ncai stacking density of cages within the rack because each row of caizes was verticailv separated from adjac-cm rows in the rack by at least this combined height.

z Filter caps for ammal cages used within ventilated cage and rack systems are also well known in the an. One such filter cap is disclosed m U.S. Patent No. 4,640,228, assigned to Lab Products. Inc.. in which a cap body with a pei-f-brated top wall is provided. A sheet. of filter, material is sandwiched berween a r..=e.- and the lower surface of the perforated top wall of -,he cap body. The retainer is detachably mounted inside the cap body in flush abutment with the filter material placed against the lower sur,'L'ace of the top wall of the cap body. The retainer comprises a narrow border portion and -flat cross arms which intersect at an integral central portion.

"i"liis:)nor art filter cap was satisfactory. However. because the retainer was secured to the caD bodv on the interior of the caD body, chanzincy a filter with an animal Within the cage was inffibited because the entire filter cap required removal from the cage to remove the -,ainer and clhange the filter. Moreover. because the substantially open. the bortorn side of the filter was substantially exposed to,iniimais Within the cage who might damage the filter. renderring it ineffecrive and resultinz in contamination or -, eau='g additional structure such as a wire bar lid Sor protection of the SIter.

Another such filter cap is disciosed in U.S. Patent No. 4,480,587, assigned to Lab Products. Inc., in which a cap body with an open top portion provided with a ledge and cross arms is provided. A filter is detachably secured to the cap body by an overlaying protective plate member which is fastened over the 1,ecis!e and cross arms using a plurality of fasterien, such as threaded bolts which pass through hoies in the plate member. filter and cap body and secured by resDecrive nuts.

This prior art filter cap was aiso satisfactory. Howeve,. because ser)arate fasteners were used to mount the protective piate c the cap lbody., personnel changing a filter were required to use special tools to remove the protective piate to reiease the Filter. The use of such

3 tools required additional resources and was time-consuming. Moreover. because the cap body had a substantially open top. the bottom side of the filter in tIlis design was also unprotected from animals within the who =c-,ht darnage the filter and reender it ineffective. Ln addition. the substantially open tot) dihibired changing a iter with an animal within the cage because of the possibilin, that the anuimal could escape through the open top. Ty picaily,:he cages in a rack system must be removable from the rack system to provide access to the animals for feeding and testing, and to the cages for cleallIngy, mainteriance and transDorT. However. it also required that te rack air source and/or water sourct mare with the cage to provide air and water to the cage. To accommodate this requirement it is known in:he art to provide a str_zcrure so that the valve in each cage is connected to an air and/or water plerium on the rack by a coupling system. In such a system. each cage is connected to the plenum by pushing zhe cage into a rack unti., 'lie coupling at the rcar of the cage is connec=ed to the coupling provided on the plenu.m. The couplings are disengaged by simply pulling the cage out of the rack. whic,;,. closes a valve within the Plenum coupling to prevent the escape and contamination of water and air. One such svstem is disclosed in U.S. Patent No. 5,042. 429.

-s. Inc. 7hese prior art animal cage rack systems provide a friction itting assiemed to Lab Product 6o maintain the connection between:he couplings. 711hese couDiings have been satisfactorv.

However.:hev sufffer:Erom the disadvaniaze that.;f the casie is not properiv installed in the rack or is accidentally burzirt- during use, the couniings maybecome parrially or wholly disengaged.

:0 In such an event, the water valve may be stuck open. flooding the cage.

Lockine mechanisms have been desicawned zo wevent a caize from beine accidentally uncoupled from the pier= orice the cage I's properly installed. However. -hese prior art designs have been large. c=bersome and expensive. -Moreover. modern cage and rack systems must allow cages of various lengths to be accommodated within the rack. The locicinsz

4 mecharusms of the pnor an do not easily permit the secure locking of cages of various lengths witlun the rack.

Accordingiv, it is desired to provide a ventilated cage and rack system which max=zes the-stAcking density of cages within the rack. it is also desired to provide a filter cap for animal cages used Ln a ventilated cage and rack system which permits easy changing of the filter while an a=al is within the cage and which protects the filter in use from damage caused bv the a=al. It is farther desired to provide a siMple arnmal cage rack locking mechanism which enables an -operator to lock cages of vanous lengths within a rack.

SUNTNI-ARY OF THE EN'VENTION Generally speaking. in accordance with the instant invention. a ventilated cage and rack system which maximizes cage densiry within the rack is provided. The rack includes at !-last one air exhaust pier=, and at least on- canopy disposed within the rack. The canopy is capable of supporting a first cage within the rack above the canopy, and also positio=g a second cage below the canopy so as to maintain a szaD between the tor) of the second casm and the canopy to DC=t air to be drawn into the air exhaust plenum from the interior of the second cage through the tor) of the second cage and to also permit ambient air to be drawn across the top of the second cage into the air exilaust pier=.

Generally speaking, n accordance with the instant nvenrion. a filter cap for an open-top cage is further provided. T1he filter car) includes a substanriaily rigid bonnet adapted to cover the open tor) of the open-top cage. The bonnet includes a body portion With a perforated or). and side walls extending therefrom for=g an 0Den bottom end. Ilie filter cap also includes a subs-cantiaily nwid filter retaine.r sized to 5: upon the bonnet and to substantially cover te perforated top of the bonnet. The filter retainer includes a tOD end with pertbrations substanriaily coexterisive with the perforations in the top of the loorinet. and side walls extending from the top end of the filter retainew, fO=a an open bottom end. the perlorations; m the filter retainer being substantially in alignment with the perforations in the bonnet when the filter retainer is mounted on the top of the bonnet. The filter cap ffinher Includes securement means for derachably securing the Siter rerainer. to zhe bonnet to permit cricosure of a sheet of filter maienai therebetween. the securement means beinR inte!zraily formed in the bonnet and the filter retainer.

Generally speaking, in accordance with the instant invention, a member for locking a cage within a rack is still Rirther provided. TI he c-age is capable of being inserted into or removed j= the rack along a slide path. The member for locking includes a base member and a restraining member rotatably mounted to the base member. The restraining member has a mst end and a foot disposed on the f=t end. The restraining member may be rotated between at least a f=t position Sor locking a fint cage or a predetermined llength within the rack and a second position for!ocking a second caú!e of a different slú-c than the first caecvthin the rack.

- 1 V1 A Accordingiy, it is an object of the invention to pro ide a ventilated cage and rack s,vstem which maximizes the densirv of caecs within a rack.

1 jZ -.nother o0JJect of:he uivenrion is to ProVide a ventilated cage and rack system which does not require distinct shelving for positioning and supporting cages within the rack and which thereby maximizes the proportion of space within:be rack which may be occupied by cages. further object of he invention is to pro,.de a ventilated cage and rack system :0 with canopies which position and support cages within the rack without additional shelving and which guide exhaust air drawn from cages nthin the rack to an air exhaust plenurn to remove exhaust air from the rack without conia=ation of personnel or cross-contar=ation berween caecs within the rack.

6 Still another oblect of the invention is to provide a filter cap for an open-toD cage which permits a filter to be securely mounted yet easily and cuicklv changed.

srill ft=her obiect of the invention is to provide a filter cap for an open-top cage while arum h xhich permits repiacement or a rilter, i als are within the cage and whic prevents such animals from escaping during filter replacement.

Yet another object of the nvention is to provide a filter cap for an opentop cage which protects the filter from darnage caused by animals within the cage.

_.-Vvet still further object of the mivenrrion is -to provide a filter cap for an open-zop caec which recuires no sDecial tools to reoiace the filter.

Another object of the invention is to provide a locking mechanism for locking a cage within a rack which is capable of locking cages of a ciuralirv of different sizes within the rack.

Another object of the invention is to provide a locking mechanism for locking a cage within a rack which easily and quickly allows secure lock-ing and unlocking of a cage within the rack with a minim= of effort and a minim= number of naris.

Jsmother object of the invention is to provide a locking mechanism for locking a cage withm a rack which is readily visible and allows an operator to easily determine whether a cage is properiv secured within the rack.

Still other otiects and advantages of the Invention will in part be obvious and Will m pan be ar--arent from the specifications and drawings.

The invention accordingly comprises the fearures of construction. combination of elements. and arrangement of parts which will be exemplified in the constructions hereinafter sei iaims.

forth- and the scolpe of the invention will be indicated m the c& BRrEF DESCRIPTTON OF THE DRAWINGS For a 511ler understandine of the invention. reference is had to the followl.1127 descrT prion taken in connecrion with the accompanying drawings, Ln which:

FIG. 1 is a -:iont eievationai View. with partial curaway, of a ventilated cage and R rack system constructed in accordance with the present invention:

FIG. 2 s a secrionaiview taken- along the line 2-2 of FIG. 1; FIG, ': 15 a DCrSDecrive view. partially in phantorn. of a cage with a filter car) positioned within a ventilated cage and raclk. system constructed in accordance with the present Invention; FIG. -' is a perspective view 01 a portion of a ventilated cage and rack system constructed m accordance with a second embodiment the present invention; 7';s a setional % 4 1G. - -iew taken alone the line 5-5 of FIG. 4; nve view or a portion of a ventilated caze and rack system FIG. 6 is a perspect constructed in acCordance with a third embodiment of the present invention:

FIG. 7 iS a sectional view taken alone the Line 7-7 of FIG. 6; FIG. 3 is a perspective View of a portion of a ventilated cage and rack system constructed in accordance with a fourth embodiment of the present invention; F11 G. 9 is a sectional view taken- alone, the line 8-8 of FIG. 9; EG. 110 is an C-XlDloded permeciive partial View of a cage level barTier cage construcied in accordance with the present invention:

1-71 j IG. 111 Is a top plan view of a fliter. car) for an open-tor) cage constructed in accordance with the present invention:

FIG. 12 s a sectional vi ew taken along the line 1-2 - 12 o f FIG. 11; FIG. 13 is a sectional view taken aiong the line 13- l' of FIG. 11.

FIG. 14 is a sectional view of two stacked cage'bottoms constructed in accordance with the present invention.

-z FIG. if s a pe.-si)ec,,ive view ot - a member 'for locking a cage within a rack constructed m accordance with the present Lrivenrion in which the member is in a locking position for locking a short cage within the rack:

FIG. 16 is a sectional view taken along the Line 16-16 of FIG. 15 FIG. 17 is a sectional view taken alone the line 17-17 of FIG. 16:

FIG. 11S is an exploded perspeenve view of a member for locking a cage within a rack constructed in accordance with the present invention-.

1 'S M. 19 is a perspective view of a member for lockincy a cage within a rack cons=c-ted Ln accordance with The present nven:ion Ln which the member is in a locking posirion Sor locking a long cagewithin the -12CK.

FIG. 2.0 is a sectional view taken along the line 20-20 of FIG. 19: and FIG. 21 is a sectional elevational view of a member for locking a cage within a rack constructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED ENMODINMENTS

Reference is 5ist made to FIGS. 1-3. wherein a ventilated cage and rack system. generally indicated at 10. construc,Ied in accordance with the invention is shown. Ventilated cage and rack system 10 includes an open rack 12 having a left side wall 11 and a right side wall 13. a tot) l -5. and a bottom 17. A pluraliry of posts 19 are disposed in parallel between tOD 15 and bottom 1 -7. Verrical posts 19 we preferably rarrow and may compnse walls exte-.idizg substantially from the front of rack 1.2 to the -ear of mck 11 or may each compnse two verricai members. one at or near the 7ont of rack 12 and the other at or near the rear of rack 11.22.

9 Ventilated cage and mck sysierri 10 also includes a plurality Of air supply plena 40 and air exhaust plena 4.21 alternately disposed in parallel between left side wall 11 and right side wall 13 substantially in the rear of rack 12. Air is 1.5orced into air supply plena 40 by a blower 4.1 ihrouac-,h an air supply conduit -16. said air suppiv conduit. 16 cornrriunicating with each air supply plenum 40 through a side wall of the rack 11 Blower 44 preferably contains an air filter for SUDPIVi115Z filtered to rack 12. kir is withdrawn from air exhaust plena 4-7 by a vacuum 48 through air exnaust conduit 50, said air exhaus', --onduit 50 communicating with each air exhaust plenum 42 zhrou(-:,h a side wall of the rack 12.

A plurality of cage level barrier caaes (cages 20) may be positioned within rack, 122. Each casze is formed of a gas impermeable bottom portion 22 having an upstanding sidewail 21 and a filter cap 24. Filter car) 24 may have an overhang 26 which extends over the top end of tail below. but bottom portion 22. Filter car) 24 is preferably a I.-Ilter cap as described in more det may also be a filter cap as known in the art. such as the filter caps disclosed in U.S. Patent Nos.

4,480.587 and 4,640.2-18, assi--ned to Lab Products. Inc.

Cages 20 are positioned within rack 12 by canopies generally indicated at 30.

Each canopy 30 shrouds a cage 20b, below a canopy 30. Accordingly, each canopy 30 is shaped and positioned so as to substantially surround die filter cap 24 of the cage 20b while maintaining a short gap h between a top 25 of filter cap 24 and canopy 30. Ga13 h should be sufficient to allow movement of gases between canopy 3.0 and filter cap 24. and in an exemplary embodiment L7ap h is 33116 of an inch to 1/4 of an inch. Canopy ^30 proffles flilter caD 24 and overlaps overhane 26 of filter cap 24. preferably creating a tens.on fit aL7ainst the sidewall 21-31 of bottom porrion 22 of cage 20b. 7Ihe rear of canopy 30 is attached to air exhaust plenum 42.

Canopies 330 are disposed in parallel columns in rack 122 between each pair of adjacent posts 19. or between left side wall 11 and an adjacerituost 19, or between right side wail 11 j io 13 and an adiacent post 19. Each canopy 3330 supporis a first cage 20a above the canor)y _330 in the rack 12 and shrouds the filter cat) 24 of a second ca-ge 20b beiow the canopy 30 in the rack 12.

T 1.he bottom portion 22 of the first caze 20a rests on top of the corresponding canopy 330. Of course. those canopies positioned at the rot) row of rack 122 do not support a caize -10 above them. and those cages _20 positioned on the bottom row of rack 1-2 are preferably supported by bottom 17 of rack 1-7. When positioned in the rack. each cage 20 cotnmunicates With air supply plen= 40 through a cage coupling 52. Such cage couplings are known in the art, and are disclosed. for example. in U.S. 'Parer, Nos. -1.989-545 and 5.042.4229 assigned to Lab Products. Inc. Air supply piena 4.0 may afso inciude means for delivering a supply of water to cages -20 throufn cage _10 couniin2 52-1. as is also known in the art. Canopies 30 are preferably constructed of a lightweight.

transparent material which is substantial1v ri.-id. such as clear plastic. Such clear plastic canopies provide enhanc-ed visibiary or cages 220 within rack sys-,ern 110 and reduce the overall weight of rack svstern 10.

le,.-e-..lne in narricular to FIG. 3. a caúze 20 is nositioned within rack 12 and 2 coupled to the air supply pienurn 40 through cage coupling;-. 3lower 44 forces air into the air supply plenum -10 in the direction or arrow A, and air is consequently forced into cage 20 through cage coupling 527 in the direction of arrow B to supply air to a=als within the cage.

Vacuum 48 withdraws air J= air exhaust plenum 42 'm the direction of arrow C, thereby creatini, a ne2ati-,,e pressure within d:ie air exhaust plenurn -12. Ducts 43) are formed in air exhaust pier= 42 below the position at which canopy 30 is attached and communicating with gap h. permirring air below canopy 330 in gap h to be drawn into air exhaust plenum 42 causing a negative pressure within the space de,.-ineci by canopy 30. 7hus. air is drawn frorn the cage '0 below the canopy 3.0 through filter top 24 U1 the direcrion of arrows D and into the air exhaust I I plenum 42. Ambient air:-om the room in whicn rack 12' 15 siniared is also drawn across the rop 25 of filter can 24 through the oven front of canopy 3330 in the direction of arrow E.

Since canopy 3330 efffecriveiy surrounds filter cap 24 includinE overhang 26. canopy,0 effecrIveiv isolates 51ter Cap '0 7om:he remainder of the cage 20 which it covers. as well as from the remainder of caszes 20 Within the rack 12. Accordingly, any gases passing -from cage 20 around or underneath overhang 26 remain'%ithin canopy 30 until removed by air exhaust plenurn 4 n 42 through ducts -13. Additionaily, because overhang 26 is contained within canopy -10 when ce 20 is r)ositioned zherei aL in. contamination due to 2as exc.lan2e berween adiacent ca2es is severelv reduced. Bv oroviding a ventiiated mack and cage system utilizing a negative pressure air exhaust plenum in which air is drawn -'-om a small confined space provided by the canopies -0 and filter TOPS 24. an open ventilated rack is provided which also provides for personnel, prote-c',ion as well as animal proreczion- Referiing to FIG. ---, a first o-mbodiment of canot)v 10, generailv 'indicated at '10a. lompnses a Top piate -'- I a. 'I op plate 1 a extends from the air exhaust plenum 42 above ducts -43 at least the len--th of fhter c--t) -'4 of a cage ZO positioned beneath the canopy 30a. as well as at least to the:7ont end of the bottom portion of a cage ZO positioned above the canopy 30a. Top plate 33-1a is preferabiv as long as a cage 20 itself, including filter car).24. Canopy 310a further comprises a left side piate -'--'-a and a right side;)late 335a which each depend substantially Ia. Side plates "a and -335a ges -a and perpenciiculariv from opposite side edL -34a of top plate are preferably disposed at a distance from each other which is substantially the same as or sliehtiv arearer than the width of filte.cap 24. Canopy 30a also comprises lips 37a and xhich each extend Perpendiculariv from side plates -3-a and -'-,a respectively toward cage 20.

Lips 37a and 39a are disposed so as to extend underneath at least a portion of the overhang Z6 of filtercap24. Lips 37a and -'Qa are substantlailyparallei to top piate 3Ia and are each preferabiy 1 n disposed at a distance from top plate 331a which 's substantially the same as or slightly grealer lan the height of filter cap 24 plus gap h. In this manner, any gases escaping from overhang 26 are held m. the canopy by lips 37a and -39a and will be drawn away through ducts 433 in = c,cnaust Dierrium 4-7 at the rear of canopy -30a.

Canopy 30a is preferably mounted to air plenum 42 at the rear and to rwo posts 19 at the front of rack 122. Each post 19 preferably comprises a vertical T- beam. with a first face 19a being disposed substar-1, h lally parallel. to the direction of inserTion of a cage 20 into rack 12 (whic:a th direction Lndicated by arrow E), and a second face 19b be' a disDose.; is paraile.; e - 1 ing - substantially perpendicular to said direction of insertion. Each side of face 19b is provided with To maximize ho i ontal cage densiry within rack notches 19c for supponing canopy 30a therrein riz 12. notches _^Oa preferably extend as close to face 19a as possible. and face 19a of post 19 is pre,.-e-.ablv made as narrow as possible while still providing srnicrural support for rack 12. By providing such a notched T-bearn post 19 on each side of canopy 30a. canopy 30a may be supported on both sides from the front of rack 12. Othermeans of providing the suppori of posis 1 19 are contemplated by the invendon. For example. a notched L-beam post 19 could be used.

zhereby providing suppori to only one side of canopy -3-0a from the front of the rrack, or canopies 30a could be screwed to a flat vertical panel disposed parailei the cage insertion direction and extendine from the top to the boitom ot.,"---!ck 127.

A second embodiment of canopy 30. generally indicated at -30b. is showm in FIGS.

r -1 and 5. Instead of forming canopy 30 as a unitary member. canopy 30b comprises a top plate _^ 1b and distinct lefft and right side gmides 33)b and _^ 5b. Side c-ruides 3.3b and 35b include liDs 3-7b and 39b respectively, and side guides 33-3b and 35b. as well as lips 3 7b and 39b, se-,.,e substandally the same function as the side snudes and Lips of the first embodiment of the canorv 30a. Tor) plate 31b and side <7111ides 33b and 35b may be mounted to air exhaust plenum 42 and 1 is Posts 19 in the same manner as described in the fu-st embodiment of the canopy 30a. In addition. side guides 33b and 35b may each be provided with a catch 36b extending toward filter car) 24 when a ca-ae 0 is in position within canopy 30b so as to hold filter car) 4 more securely Ln place upon the bottom porton = of cage '0. Catch 36b may strengthen die seal between filter cap and bottom portion 2122 ofeage 20. Catch 36b also prevents animals Within the cage from pushing filter cap upwards. Which could comprise the seal between filter cap 24 and bottom portion 2. and which could also close zap h thereby disrupting:he clean flow of air between top plate of filter cap '4.

lb and top 50, generally indicated at 30c. is shown in FIGS. 6 A third embodiment of canopy 1,0 and 7. Canopy 30c comprises a:op plate 3l c which serves as a top plate for all canopies 30c in :he same row within rack 12. Side zuldes ---^-c and -335c are provided for each cage 20 positioned 'ic and 35c preterably inc;ude tabs --virhin canopy -30c. Side gul -- -- - 1 1 38c which are aligned ldlin slots 3 Sc of top plate 3 1 c, and side guices 33c and 35c are preferably welded to top plate -lc. Side guides 33c and 35c incitide respective first lips 3357c and 3. 9c protruding toward a cage 0 uosirioned between side guides 33c and "c and fl-orm a canopy with top plate 31c. Side --uldes 333c and 35c, as well as lips 37c and 39c, serve substantiaily the same function as the side guides and lips of the dni embodiment of the canopy -30a. Top plate 31c and side guides 33c and 35c may be mounted to air exhaw. plenum 42 in the same manner as described in the f=r embodiment of the canopy 3-10a. Lri addition. side (--niides 33c and 3.5c each include second lips -c' and 3 9c' which each extend in a direction opposite that of first liDS 3 3 7c and 3 9c respecriveiv.

3.7 ic' and 39c' thus serve as corresponding lips 39c and 37c respectively of the canopies.o "c ieft and right of canopy 30c if such adjacent canopies exist in rack 12 (i.e. unless canopy -,Cc s M the le.,bnost or na-htmost colu= of ihe rack 12). By providing a single structure which 14 serves as a side Tuide,-or two adjacent cages. less horizontal space is required for canopies 30c in rack 122 and the horizontal stacking density of cages 20 in the rack may be increased.

fourth embodiment of canopy 30. generally indicated at 30d, is shown im FIGS.

3 and 9. Canopy -Od comprises a top plate _^ ld which serves as a top plate for all canopies 30d in the same row within rack 12. Side guides 33d and 115d are provided to form the canopy With tot) plate 33-1 d for each cage 20 positioned below canODV 30d. Side ognudes 333c and 35c preferably mclude flanges 36d which are welded io top plate 31d. Side guides 33)d and 35d u'iciude respective first libs 37d and 339c:)rotruding toward a cage _O positioned between side guides 3333-d and 35d. Side -uldes and 35d. as well as lips 37d and 39d. serve substantially the same anction as the side gruides and lips of the first embodiment ofthe canopy 30a. Top plate 31d and side --uldes 3333-d and 3335d may be mounted to air exhaust pien= 42 'in the same manner as desc-711bed in the first embodiment of the canopy 30a. in addition. side guides 33533-d and 33-55d are ide guide of an adiacent canODV in the rack 12. preferably by each mounted flush against a si 1 welding. By providing flanges for mounting the side gruides to the tOD plate. and by mounting adjacent side gruides directly to one anot.-,. a stronger and more ncrid overall rack 122 may be achieved while sLrnuitancousiv maximizing cage density within Lhe rack.

Accordingly, because each canopy 30 acts as both a support for the cage 20 above it m rack 12 as weil as a shroud over the filter car) of th --asze 20 below it M rack 12 which a'des exhaust air from the cage as well as ambient air into the exhaust pier= 42. ad tionai ul di i shelving is not needed -o position and SUDPOrl CaReS 20.,"itiiin rack 20. As a result, cages 20 may be vertically positioned closer together in rack 12 than in a rack having distinct shelving.

Zherebv advantageousiv increasing the stacking density of cages _'0 within rack 12. Re.ference is now made to FIGS. 10-!--. Ln which a filter caD, generally

indicated at 0, for an open-top cage, such as cages 20 described above. constructed in accordance with the mvention is shown. 1117;lter car) 770 is conflgrured to cover the:or) of a cagge bottom. generally indicated at 60. Caize bottom 60 is formed with intezrai side wails 6 1. a bottom wall or floor (not shown) and an open - opend. The wails are preferably formed of a clear =sparent plastic such as volvcarbonate. wiiich is:-iggid. durable. permits ready inspection of animals. has a high impac, 5 strength, and is machine washable or autoclavable at temperatures under 2_50 degrees Fahrenheit. Such a caee is conventional, commercially available. and widely used. A standard absorbent bedding of p articulate material such as wood chips (not shown) may be spread on the floor. The open top of cage bottom 60 is bordered by penpherai lip 63 which extends continuousiv therearound. Caze bottom 60 mav also mciude corne.- stackinL, tabs 65 for added stracrurai 'or stacking a piuralin of cages bottoms as shown in FIG. 4.

support and f Filter car) 70 may be formed as a lavered construction includinsz a bonnet.

generally indicated at SO. in the general shape of a shallow tray or box. a retainer 100, and a filter 99 thereberween. Bonnet 80 is preferably formed of clear.lastic which is substanrially rigid but oerrrruts a modest degree of flexure when torsional forces are applied thereto. As shown in FIGS.

10-13, filter cap bormet SO has a perforated top wail 92 which is integrally molded with a inareyinal narrow border 96 extending contmuously around the top of filter cap bonnet 80. Top wail 92 is provided with a plurality of perforations 94. preferably of generally square confc-uration and forming a gnd array. Respective opposed pairs of side walls 82 depend substantiallv orthozonail,,, 57om rot) wall 92. The surface for7ned on bonnet 80 for restin- filter cap 70 on cage bottom 60 includes a continuous lateral peripheral flange 88 extending generally perpendicularly ourwardly fl7om side wails 32. A continuous peripheral flange 90 depends from I ateral peripheral flange SS to encOMDass the open rot) of cage bottom 60. Ribs 86 extend fr-cm z1ange 90 to allow stacking of the bonne, 80.

16 As shown m FIG. flange 90 is spaced from. enco=asses and overhangs lip 63 of cage bottom 60. 7hus. filter cap bonnet 80 cannot be inadvertently dislodged from cag c 1 - bottom 60 and must be lifted off to be removed. It should also be noted that the clearance space between rlane_ 90 and 5p 63) should permit only a sight movement of filter cap 70 on cage bottom 60. However. peripheral flange 88 is Dre,."e.-ablv of sufficient lateral extent to remain in contact with lip 63 despite any relative lateral movement between filter cap 70 and cage bottom 60. therebv maintaiffinLY the integrity of the--- petri dish" configuration between filter cap 70 and cage bottom 60. - Filter cap 70 is also provided with a filter retainer 100. Filter retainer 100 Is preferably formed of material havinsz the same properr.les as those of bonnet 80 described above but with a different rigidity. Filter retainer 100 detachably and securely maintains an air Biter 99 to the top surface of top wall 92. Filter retainer 100 LnCludes a generally flat perforated top wail 104. TOD Wall 104 includes a substantially rectangular border portion 102. An outer edge 106 of border portion 102 is Joined to inTegrailv molded side wails 108 which depend therefrom and extend continuously from top wall 1104. and which c.oseiy f5it side wails 82 of filter cap bonnet 80. as shown in FIGS. 'I'-' and 1 _3, - A lateral peripheral:1ange I 10 extends from side wails 108. Ribs 86 extend from the respective corners of filter retainer 100 and provide structural integrity. Additionallv nbs 86 act as stacking guides for positioning, a top bonnet 80 of a second filter cap 7 0 atop first filter cap 70. The top surface of border portion 96 of bonnet 80 is provided with a pair of spaced-apart integ:rally moided ribs 97, 98 which extend continuously therearound. Each rib -7, 98 has a generally convex crosssec.ion as shown In FIGS. 12 and 1"), and the nbs are disposed to project between a group of diree similariv-shaped SDaced-apan ribs 112, 114. 1 16. which are integraily molded on a bottom surface I IS of filter -rezainer border 102.

1 1 1 In a Preferred embodiment. air filter 99 is a thin sheet of spun-bonded polyester of (IN the type sold by DuPont under the trademark REEKkY _20 24. A filter thickness of berween 1. 1 and 13 mils has bean 'bund adecuate for a filter having an area ap proximately equivalent to the area of filter cap top wail 92. Air r-ilter 99 Is mounted on the top surface of filter cap bonne, SO U 1A and is he.1d in place by 51ter retainer 100 in a mannerto be now described. REEIMAY 20 24 is used by way of example only and any filter medium having at least its properties or similar properties may be utilized.

To asserrible filter car) 70. air,-ilter 99 is,,laced asrainst the bottom surface of,oD wail 104 of filter reminer 100. Thereafter. filter cap bonne,, 80 is mounted atop filter retainer 100.

io Ribs 97, 98, 112. 114. 116 interlock such that db 977 proi ects between ribs 112 and 114. while rib 98 proi acts between ribs 114 and 116, as shown in FIGS. 12 and 13. Ribs 97, 98. 11-3. 1.14.

1 - 99 securely in place agairist the top surface of top wail 92. Top L 16 thus also se,--,.e to hold filter wall 104 of filter retainer 100 is; provided with perforations 120 which are preferably substantially coextensive and in alignment with perforations 94 in top wall 92 of bonnet 80 when SO.

filter retainer 100 is mounted arop bonne, The mesh structure of tot) wall 92 serves to - filter 99 from sagg-ging and holds air filter 910. while filter retai er 100 holds filter 109 prevent air 1 in securely in place against the top sur---race of Lop wall 92. in the assembled filter cap 70, perforated top wail 104 ove,,iies filter 99 10 Drotect the filter against damage during handling and prevent its movement or buckling, whi-le filter 99 rests flush upon perf-orated top wail 92 of bonnet 80 which supporTs and protects aw filter 99 in its mounted position. Additionally, touching the filter with fineers may destroy the filter inie22-irv, and therefore the 13erforated walls on either side of the filter prevent contact with the filter. by the technician ciunng handling and also prevents contact with the filter by the animal. remoVLne the necessity for a wire bar lid aria ncreasino' the useable volume of the cage.

is Filter retainer 100 is held Ln place,y means of small projections or detents 84 which are integrally moided on the outer surface of side wails 82 of filter cat) bonnet SO. As sho,%vn in FIG. 11. four spaced dettents 84 are molded on each long side wail 82 of bonnet 80, and -ents S4 are molded on each shorter side wall 32. Each of the detents 84 has a two spaced det convex or arcuate free end. as shown in FIG. 13. Similarly, apertures or-slots 122 are formed in side wails 108 of filter retainer 100 which are positioned and duriensioned so as to snugly receive dezems 34 when filter retainer 100 is mounted on bonnet 30. In an alternative embodiment. detenis 84 could-be formed on the inner surface of side wails 108 of filter retainer M, whiie slots tZZ would. be f-ormed in side wails 32, of bonnet SO. it 'is also possible to dimension filter retainer 100 to be held to bonnet 80 by a tension fit.

1 z Deterits 84 are precisely molded on bonnet. 90 and are spaced from top surface 89 of,jeripheral flan-e 38 bv a distanc- siiahrly greater than the i-eight of integral peripheral flange 110 of the filter retainer 100. A-fter air filter 99 has been positioned again i the bottom surface of top wall 104, filter cap bonnet 80 is moved downwardly 'upon filter retainer 100 toward the perforated top wall 104 thereof to permit detents 84 to erigage siots I--. Side walls 108 of filter retainer 100 flex outwardly so that slots IZZ snap past tabs 3-1 to the mounted position shown u-1 FIGS. I 1- 13. In this mounted position. the top surface 111 o f lateral peripheral flange 110 is held beneath the bottom surface of deteenis S4 and is restrained thereby, With ribs 112, 114 and 116 on the bottom surface of border portion 102 eng7a=_(g the:op surface of the edge portion of air frilter 99 and pressing this filter portion against rlbs 97 and 98 of filter cap bonnet border portion 96. At the same time. the meshed structure of perforated top wail 104 of filter retainer. 100 engages the top surface of air filter 99 and presses filter 99 firmly again t the top surface of rot) wail 92 of bonnet 80. Air filter 99 Is thus sandwiched between filter retainer 100 and the:or) suriace of top wall 92 of bonnet 80. and may be retained m this mounted position by the engagement of detents 84 upon flange 110 offilter. retainer 100. Furthermore, the mesh srrucrure of top wall 92 protects air filter 99 by forming a rigid barrier between anitnals Within the cage and air filter 99. To this end. it is preferable that perforations 94 are sufEciently smail..he thickness of Lop wail 92 sufficiently =cat. to prevent an animal within the cage from causing substantial damage to air filter 99. Filter cap bonnet 80. reminer member 100 and air -L-ilter 99 may thus be 51rinly locked in a mounted position so that they cannot be accidentally dislodged during autoclaving or 1handling. An assembled filter cap 70 can thus be lifted and removed from cage bottom 60 for all normal functions such as feeding, wearing or examining animals tberein,xthout disrurbincy or dislodging air filter 99.

Perforated top walls 92 and 104 permit rough handling of filter cap 7/0 Without causine damage to filter 99, and the entire fi,Iter cap can be autoclaved as a unit for conrinuai reluse. Since rlange 90 closely envelops the open top of cage bottom 60, there is minimal loss of sDace m a cage rack when cages are ffi close proximity to each other, and the abutting of one filter caD -70 azainst another filter caD 70 is unlikely to dislodge the filter caDs from their respective cages.

Wlien it becomes necessary to repia.-! or remove filter 99 from filter caT) 70. one must merely grasp opposing sides of the perimeter of bonnet SO. such as at lateral peripheral flanze 88, and twist or flex filter cap 70- 0ne of the bonnet 80 or retainer 100 is more rigid than the other. Due to the different degrees of f1exure inherent in bonnet 80 and filter rerainer, 100 imparted by the materials from which they are constructed. bonnet 30 and filter retainer 100 will flex relative to each other when a torsional, twisting.1orce is applied to filter cat) 70.

17, I urthermore. this flexure will cause ribs 86 of retainer 100 to push against surface 88 of bonne pushing retainer 100 away from bonnet SO. As a result of this r-orce, lateral peripheral flange I 10 of filter retainer 100 will be forced upwards and over detents 84 of bonnet 80, thereby i releasing filter retainer 100 from bonnet SO and expos1rig air filter 99. Once a new filter 99 is I - replaced on top wall 104 of retainer 100 as described above. filter bonnet 80 is then replaced and snapped into its mounted position to secure the new filter. In this way, filter 99 can be changed with a mlrumurn amount of nMe and effort.

By providing a filter cap for an open-t0D cage With a perforated filter retainer which snaps onto a similarly perforated bonnet. a filter for an animal cage top may be easily and quickly changed. By providing the filter above the perforated top wall of the bonnet. the:lter may be replacedwhile the bonnet is on the cage to ensure that animals within the cage are not permitted to escape while the filter is being replaced. In addition. the substantially rigid mesh structure of the top wall of the bonnet protects the filter from damage caused by animals within the cage, and a separate -guard for the filter. such as a wire bar lid. is not necessary. Moreover, by securine the filter retainer to the bonnet. with an integrally formed securement means, such as tabs and slots, no special tools are necessary to remove the filter retainer for replacing the filter.

Reference is now made to FIGS. 3 and 14. in which a particular configuration of is an animal cage is shown which serves to maximize the number of animals which may be maintained in a cage rack system of a eiven size. Each cage is rea. ed to provide a 1 - -!Uir predetermined square area per animal contained in the cage. it is possible to increase the area within the cage by extending the length of the cage. the depth of the cage. By providing increasing the bottom area by extending the cage, it is possible to increase the number of animals within the cage without increasing the associated width or height so that rack and canopy systems as described above can accommodate both the conventional cage and the new larger Cage.

Reference is now made to FIGS. 15-Z 1. wherein a locking mecharusm, aenerallv indicated at 150, constructed in accordance with the present invention to retain both sized cages 71 is depicted. Locking mechanism 150 locks a cage 1,30 within a rack system 140. Cage 1330 is removably disposed within rack system 1.40 along a slide path. generally indicated by arrow F. Caize 130 is preferably a cage 20 including a filter cap 0 as discussed above. and rack svstern 140 is prete ' rably a ventilated cage and rack system 10 as also discussed above.

Locking mechanism 150 includes a base member 160 and a restraining member 170. Restraining member 170 is rotatably attached to base member 160. Base mernbe.- 160 is attached to rack system 140. In the lockinsz mechanism 1. ','0 discussed above. base member 160 is disposed in a locking position such that foot 174 of restraining member 1.70 is interposed within the slide path of cage 130 to lock cage 130 within rack system 140. Base member 160 is preferably rotatably attached to rack system 140 so as to be rotatable between a locking position shown in FIG. 21, in which caze 130 is secured and locked within rack svsTern 140. and an unlocked position shown in phantom in FIG. 2 1. in wruch caZe 1 0 is unlocked fa7orn rack system 140 and may be freely inserted into or removed therefrom. The locking position is also shown in FIGS. 15-17, 19 and 20.

1 iz 1 To pe=t rotation of base member 160 between the locking and unlocked positions xth respect to rack system 140. base member 160 is preferably rolarably attached to a vertical post 142 of rack system 140. such as vertical post!,. of ventilated cage and rack system 10 iscussed above. As best shown n FIGS. 16, 18 and 20. base member 160 is preferably mounted to a portion of post 142 which is perpendicular to the slide path ol cage 1-30. Base member 160 is preferably mounted to post 142 utilizing a bolt 200, a washer 208 and a nut 21.1 Bolt 200 comprises a shaft 204 bounded by a head 202 at one end and a threaded portion 2.06 at the other end. Bolt 200 passes through a hole 167 in base member 160. A shoulder 169 in hole 67 engages head 202 and prevents flirthe.r movement of bolt 200 toward post 142. Bolt 200 next passes through a hole 210 in washer o08. and thereafter through a hole 144 in post 142.

11 n Finally, nut 212 is screwed onto threaded portion 206 of the end of bolt 200. Washer 208 preferably comprises a compressible material, such as rubber. so that nut 212 mav be tightened to a dearee which holds base member 160 against washer 208 with sufficient tensional force to prevent base member 160 from being inadvertently rotated. However, the tightness of nut Zl-' on bolt 200 and the consequent compressive force applied to washer 208 is also such that base member 160 may be rotated by an operator between the locking and unlocked positions by applying moderate rotational force to base member 160.

Restrainin(z member 170 inciudes a first end 172 having a foot 1-4. Foot 174 is diSDOsed such-that it extends into the slide i)ath of caLye 130 within rack svstem 140 when base member 160 is in the locking position. thereby preventing cage 130 from being removed from rack system 140.

Restraining member 170 and base member 160 are rotatably coupled and held together by a pivot assembly ISO. As best shown in FIG. 18. pivot assembly 180 preferably comprises a bolt 181. a first washer, 183. a spring 185. a second washer 187 and a nut 189. Bolt 181 comprises a shaft 184 bounded by a head 182 at one end and a threaded portion 186 at the other end. Bolt IS I passes through first washer IS-33 and thereafter through a stepped hole 191 in restraining member 170.

A recess 19' 3 in restraining member 1770 is disposed concentrically with hole 191 to accept head 182 of bolt IS I to thereby prevent head '182 from extending beyond knee 173 and potentially into the slide path of cage 130, especially when restraining member is disposed in the second position discussed above. A shoulder 194 (FIG. 20) in recess 193 prevents head 182 from;--urtherr movement toward base member i60. Bolt 181 next passes through a hole 162.n base member 160. Holes 191 and 162 each have a similar diameter, which is preferably oruy slightly greater than the diameter of shaft 184 of bolt 181. Next, bolt 181 passes beyond a n ' j shoulder 1,64 and into a circular bore 166 which has a greater diameter than that of hole 162. Bolt 181 then passes through the axial cenrer of spring 185 and through a hole 188 in second washer 187, Finally, riut 1 S9 is screwed onto threaded portion 1 S6 of bolt 18 1. The diameter of bore 166 and the outer diameter of second washer 1 S7 are each at least as gear as the diarnerer of spring 185. and the outer diameter of nut I S9 is at least as great as the diameter of hole 188 ul second washer 187.

Thus. spnng 185 surrounds shaft 184 of bolt 181 and is held between shoulder 164 of base member 160 and second washer 187. In this manner. sDring, 185 biases bolt head 182 against shoulder 194 and spring 185 is compressed when head 182 of bolt 181 is pulled away from base member 160. Mhen head IS: of bolt IS I is fully inserted into recess 1933 so that Lt contacts shoulder 194, nut 185 should be screwed onto bolt 181 to a position at which second washer 187 holds spring 185 under light to moderate COrnDression against shoulder 164 when a tongue 168 and a groove 196 are mated and in contact with one another.

As shown in FIGS. 18 and 19. in a preferred embodiment. base member 160 is provided with a generally convex tongue 1. 68 in the shape of a wedge which is laterally disposed along the surface of base member 160 abutting restraining member 170. Likewise, restraining member 1 -170 is provided with a generally concave groove 196 which is dimensioned to interlock or mate with tongue 168 in a substantially flush manner. Tongue 168 and groove 196 prevent restr-aininiz member 170 from rotating with respect to base member 160 when restraining member 170 is held against base member 160 so that tongue 168 and groove 196 are mated. It is to be understood that tongue 168 and groove 196 may be disposed on the base member 160 and respectively, and may alternatively disposed on the restraining member :estraining member I'i and base member 160 respectively. It is also to be understood that tongue 168 and groove 196 may be provided in other mating shapes. including arcuate or serrated arrangements, so long 1 - - 24 as the particular shape chosen is formed symmetrically about the pivot assembly 180 to allow restraining member 170 to mate with and be securely held against base member 160 in any rotated position chosen for locking a cage 1-30 of a particuiar leno-ah within rack system 140.

Pivot assembly 180 accordingiy acts as a tensioner which biases the restraining member and the base member together, but which permits an operator to- pull restraining member 170 a distance away from base member 160 to rotate restraining member 170 for choosing a position for foot 174 which accommodates and properly locks cage 130 within rack system 140.

The distance wifich restraining member 1-70 may be pulled away from base member 160 should be sufficient to- allow. restraining member 1 7.0 to clear the tongue 168 of base member 160 in order to permit the required rotation of restraining member 170. Thus, spring 185 must be compressible over at least this distance. Afler restraining member 170 has been rotated to the proper position. the operator may release restrainirig member 170. Once released. compressed spring 185 of pivot assembly 180 exerts force agairst second washer 187 and nut 189, which pulls bolt 181 together with head 182 toward base member 160. Since head 182 rests against shoulder 194 of restraining member 170. restraining member 170 itself will be biased toward base member 160, thus pernutting tongue 168 and groove 196 to mate and to thereby secure restrai=g inember 170 in the position selected by the operator.

It is important to ensure that cage 130 does not move along its slide path within racK system 140 once cage 130 has been properly positioned within rack system 140, as a cage couipling in cage 130 (not shown) may become partially or wholly disengaged from a maring coupling within rack system 140 through which air and/or water may be provided to animals within caae 1310. When such disengagement unintentionally occurs. adverse consequences can result, such as drowning of animals within the cage by a water valve stuck open, or suffocation ot animals within the cage by a disruption in air supply. To this end. foot 174 is preferably disposed such that it substantially abuts front end wall 1,32 of cage 130 when cage 1.30 is properly positioned within rack systern 140 such that the necessary couplings are properiv and securely engaged. The substantial abutment of foot 174 against front end wail 132 thereby ensures that cage 11330 is substantially immobile within rack system 140 along the slide path. and that animals within caee 130 are therefore secure. Although abutment between foot 174 and cage 1-30 is preferable. it is to be understood that foot 1.14 and cage 130 need not be in actual cc-tact with each other. Rather..5bot 174 need only prevent cage 30 from being inadvertently moved along the slide path to an extent that any couplings between cage 130 and rack systern are aDt to become disenewred. or to an extent that caee 10 is Likely to fall out of rack system 140.

In order to allow cages 133 0 of various lengThs to be locked within rack system i 40 using the same locking mechanism 150. restraining member 1-70 of locking mechanism 150 is rotatable with respect to base member 160 acaut pivot assembly 180 to allow toot 174 to be interposed at various positions within the slide path of cage 130. For ex=ple, restraining is member 170 ir--y be rotatable between at least a first position for iocking a first cage 130 of a predetermined length within rack system 140. and a second position for locking a second cage 130'of a difEerent size than the ini caRe within the rack. Such an arrangement may be required where second cage 110' is longer than first cage 130 (that is. second cage 130' projects further from the rear of rack system 140 and any couDiings therein than first cage 110).

Using this example. FIGS. 15-17 most clearly depict restraining member 170 disposed in the first position. and FIG..0 also shows restraining member 170 disposed in the first position in phantom. In this first position. end 1'722 and floot 17- t of restraining member 170 are positioned so as to be as close as possible to the rear of rack system 140 Within the t-ange of positions available about pivot assembly 180. As can be seen. outer face 176 of foot 17,4 256 preferably substantially abuts front end wall 1-352 of cage 130 to lock first cage 130 within rack system 140.

Should I it be desired to lock second cage 130', longer than first cage 130, imn the same general p-osirion within rack system 140, restraining member 170 need only be rotated about pivot assembly 180 to the second position. most clearly depicted-in FIGS. 19-20. In the second position, end 172 and foot 17 4 of restraining member 170 are positioned so as to be as far as possible away from the rear of rack system 140 within the =ge of positions available about invot assemblv fSO. Knee 173 of restrainine member 170 is disDosed outside of the slide path of cage 13310' such- that ilde wail 134' of cage 1330' may extend alongside of knee 17-3) without interference therefrom. However, as can be seen. foot 174 is interposed within the slide path of caLye 130'ance cage 130'has been properly positioned within rack system 140. Inner face 178 of foot 174 preferably substantially abuts front end wall 132 of cage 130' to lock cage 13)0' within rack system 140.

While a two-pos1tion rotatable restimning member 170 has been described in the embodiment noted above. it is to be understood that a resumning member 170 for locking cages of more than two different lengths is encompassed by the invention. For instance, foot 174 mav be rotated about pivot assembly 180 through any plurality of positions, each of which interposes foot 174 at a different position within the slide path of cage 130. and which could thereby lock cages of the same plurality of lengths within rack system 140. - Utematively, restraining member 170 could be provided with more than one foot 1774, each of which being disposed on restraining member 170 at a different position within the slide path of cage 130. In still another embodiment. restrairiing member 170 could be siidably disposed on base member 160.

permitting foot 174 to be selectively disposed within the slide path of cage 130 by sliding restraining member 170 MSDeCtiVe to base member 160 to a desired position within the slide path for locking the cage.

As noted above. restraining rmember 1 -0 is rotatable with respect to base member 160 to allow restraining member 170 to be selectively rotated between at least a f=t position and a second position for locking cages of different siZes within rack system 140. To ensure that restraining member 170 is securely positioned with respect to base member 160 once a particular rotation has been selected. the tongue 168 and groove 196 system discussed above is pref-erably Utilized to mate restraining member 1 170 and base member 160 and to prevent rotation of the two members with respect to each other.

:0 Utilizing a bolt arrangement for mounting base member 160 to rack system 140 allows base member 160 to be rotatably screwed to post 14 9'. in a manner which moves foot 1-14 of restraining member 1/70 from the locking position shown in phantom in FIG. 21 generally upward and toward post 142 to the unlocked position in which foot 174 is removed from the slide path of cage 130. Alternatively, foot 174 may be moved downward from the locking position and toward post 142 to the same effect. When base member 160 is rotated to the unlocked position, cage 130 may be freelly moved into or out of rack system 140 along the slide path without interference from locking mechanism 150. Once caee 130 has been fully and properly inserted into the rack. base member 160 may again be rotated to the locking pcsition to lock cage 130 securely within rack system 140.

By providing a locking mechanism with a restraining member rotatable between a pluraliry of positions for interposing foot at a Dluraiirv Of DosiTions; within the slide path of cage. a single locking mecharusm is provided which is capable of locking cages of a plurality of different lengths within a rack system. By further providing a locking mechanism with a base member which is rotatable between a locking and unlocked position, a simple mechanism is 28 provided which easily and quickly allows secure locking and unlocking of a cage within a rack system with a minim= of effort and a minimum number of parts. In addition, by providing a locking mechanism which is mounted to a post of a rack system accessible from the front of the rack system. a readily Visible locking mechanism is provided wilich allows an operator to easily 5 deter=e whether a cage is properly secured within the rack system.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and,since certain changes may be made in the above zonstruction without denarrine from the spirit and scope of the invention. it is intended thar_:dl matter contained in the above description or shown in the accompanying 10 dra,,vinsrs shall be interpreted as illustrative and not in a limitine sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific fearures of the invention herein described. and all statements of the scope of the invention which. as a matter of language. might be said to fall thereberween.

29

Claims (1)

  1. CLAIMS A filter cap for an open-top cage comprising:
    a substantially rigid bonnet adapted to cover the open top of the opentop cage, the bonnet having a body portion with a perforated top and side walls extending therefrom forming an open bottom end, a substantially rigid filter-retainer sized to be substantially coextensive with the perforated top of the bonnet, the filter retainer having a top end with perforations substantially coextensive with the perforations in the top of the bonnet, the filter retainer also having side walls extending from the top end thereof, the perforations in the filter retainer being substantially in alignment with the perforations in the bonnet when positioned to retain a filter therebetween; and securement means for detachably securing the filter retainer to the bonnet to permit enclosure of a sheet of filter material therebetween, the securement means being integrally formed in the bonnet and the filter retainer.
    The filter cap of claim 1 wherein the securement means comprises at least one detent formed on at least one side wall of the bonnet, and at least one slot formed in at least one side wall of the filter retainer disposed so as -er retainer is to receive the detent therein when the filt mounted on the bonnet.
    The f ilter cap of claim 1 wherein the securement means comprises at least one detent formed in at least one side wall of the filter retainer, and at least one slot formed in at least one side wall of the bonnet disposed so as to receive the detent therein when the filter retainer is mounted on the bonnet.
    The filter cap of claim 1 wherein said bonnet and said filter retainer have sufficient flexure to allow the bonnet and the filter retainer to flex relative to each other.
GB9906360A 1996-09-18 1997-09-15 A filter cap for an open top cage Withdrawn GB9906360D0 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US08715657 US5954013A (en) 1996-09-18 1996-09-18 Ventilated cage and rack system
GB9719579A GB2317321B (en) 1996-09-18 1997-09-15 Ventilated cage and rack system

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Publication Number Publication Date
GB9906360D0 GB9906360D0 (en) 1999-05-12
GB2332612A true true GB2332612A (en) 1999-06-30

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GB9815737A Expired - Fee Related GB2325390B (en) 1996-09-18 1997-09-15 Ventilated cage and rack system
GB9906360A Withdrawn GB9906360D0 (en) 1996-09-18 1997-09-15 A filter cap for an open top cage
GB9815740A Expired - Fee Related GB2325608B (en) 1996-09-18 1997-09-15 Ventilated cage and rack system

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US6041741A (en) * 1998-06-26 2000-03-28 Lab Products, Inc. Multispecies rodent cage
GB2342841A (en) * 1998-06-26 2000-04-26 Products Lab Inc A filter bonnet for a laboratory cage
US6227146B1 (en) 1998-06-26 2001-05-08 Lab Products Inc. Filter top for rodent cage
WO2000074473A3 (en) * 1999-06-07 2001-09-07 Products Lab Inc Filter top for rodent cage
GB2365314A (en) * 1999-06-07 2002-02-20 Products Lab Inc Filter top for rodent cage
WO2008135528A2 (en) * 2007-05-02 2008-11-13 Scanbur A/S An animal cage system

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US20100108622A1 (en) * 2008-11-06 2010-05-06 Gabriel George S Locking assembly

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3877268A (en) * 1973-02-01 1975-04-15 Elixir Ind Lock assembly with resilient latch

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6041741A (en) * 1998-06-26 2000-03-28 Lab Products, Inc. Multispecies rodent cage
GB2342841A (en) * 1998-06-26 2000-04-26 Products Lab Inc A filter bonnet for a laboratory cage
GB2342841B (en) * 1998-06-26 2000-07-26 Products Lab Inc Multispecies rodent cage
US6227146B1 (en) 1998-06-26 2001-05-08 Lab Products Inc. Filter top for rodent cage
US6336427B1 (en) 1998-06-26 2002-01-08 Lab Products, Inc. Feeder assembly for use in a cage
US6336425B1 (en) 1998-06-26 2002-01-08 Lab Products, Inc. Multispecies rodent cage
US6341581B1 (en) 1998-06-26 2002-01-29 Lab Products, Inc. Multispecies rodent cage
US6526915B1 (en) * 1998-06-26 2003-03-04 Lab Products, Inc. Feeder assembly for use in a cage
WO2000074473A3 (en) * 1999-06-07 2001-09-07 Products Lab Inc Filter top for rodent cage
GB2365314A (en) * 1999-06-07 2002-02-20 Products Lab Inc Filter top for rodent cage
WO2008135528A2 (en) * 2007-05-02 2008-11-13 Scanbur A/S An animal cage system
WO2008135528A3 (en) * 2007-05-02 2008-12-31 Scanbur As An animal cage system

Also Published As

Publication number Publication date Type
GB2325608B (en) 2000-05-03 grant
GB9906360D0 (en) 1999-05-12 grant
GB2325608A (en) 1998-12-02 application
GB2325390A (en) 1998-11-25 application
GB9815737D0 (en) 1998-09-16 grant
GB9815740D0 (en) 1998-09-16 grant
GB2325390B (en) 2000-05-03 grant

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