US2550040A

US2550040A - Selectively evacuated temperature regulated container

Info

Publication number: US2550040A
Authority: US
Inventors: Clar Mottel
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-08-08
Filing date: 1946-08-08
Publication date: 1951-04-24
Anticipated expiration: 1968-04-24

Description

April 24, 1951 M. CLAR SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER 7 Slieets-Sheet 1 Filed Aug. 8, 1946 INVENTOR. 1'10 TTEL CL HE BY fidWm/W TTORA/EY.

M. 'CLAR April 24, 1951 SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER 7 Sheet s-Sheet 2 Filed Aug. 8, 1946 JTYg ZiS.

INVENTOR. [[0 T TE L C 1. RE

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M. CLAR 2,550,040 SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER April 24, 1951 '7 Sheefc s-Sheet 3 Filed Aug. 8, 1946 I///////I/I///////I INVENTOR. MOTTEL CLfl/e BY A4 M. CLAR April 24, 1951 SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER 7 Sheets-Sheet 4 Filed Aug. 8, 1946 M. CLAR April 24, 1951 SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER 7 Sheets-Sheet 5 Filed Aug. 8, 1946 INVENTOR J I OTTEL CLFl/E flTT NEY.

April 24, 1951 M. CLAR 2,550,040

SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER Filed Aug. 8, 1946 7 Sheets-Sheet 6 INVENTOR. M0 TTEL C1. A2

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April 24, 1951 cum 7 2,550,040

SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER Filed Aug. 8, 1946 7,Sheets-Sheet 7 1 I I l INVENTOE.

a Morn-L 'CLHE HTTORNEX Patented Apr. 24, 1951 UNITED STATES PATENT OFFICE SELECTIVELY EVACUATED TEMPERATURE REGULATED CONTAINER .Mottel Clar, Culver City, Calif.

Application August 8, 1946, Serial No. 689,290

'4 Claims. 1

This invention relates to storage and shipping containers oi novel construction and operation, to an improved method of preserving and transporting perishable goods such as food products and to various integral features of construction which contribute to the particular effectiveness of my containers.

It is an object of the invention to provide a food container "having means for regulating the temperature of the products stored therein such as by circulation of heated and cooled air, and further having a vacuum compartment which may either be the storage chamber or may surround the storage chamber to serve as an insulating space therefor. In "one embodiment, my container is provided with means for selectively evacuating either the storage chamber 'or the surrounding insulating space, and also with means for circulating air through whichever of these spaces is not evacuated, so that the environment of the stored articles may be adapted --to the particular product as well as adjusted in relation "to the external conditions or temperature of the region in which they are stored or through which they are being transported.

Another purpose is to provide a container of the character described which is constructed of hollow dem'ountable panels which may be assembled, for example, as the lining of a rail-road car, aircraft, automotive truck, cargo vessel or, again, may be assembled and dismounted in a warehouse or other storage "space as needed from time to time.

A further obii'ect is the provision of a reusable container of the character described which has no protruding attachments or parts so that a number of such units may be quickly and comactly stacked or lodged in a storageor shipping space, and in this connection there is provided a novel coupling assembly or high speed union for quickly connecting and disconnecting "the container to suitable external means for evacuating and/or circulating heated or cooled air through the several closed spaces as required.

An additional purpose is to :provide a container oi the character described wherein the several principal walls are effectively insulated from each other as well as from conduits necessarily penetrating the walls.

:Still another object is the provision of :a container of the character described which is provided with a hollow door or closure which may be evacuated simultaneously with an insulating space of the container; another feature is a floating :hinge construction which permits a more 2 exact and airtight alignment of the door in "the door-Way; still another feature is the provision of a door locking device particularly "adapted for a storage chamber of the present type.

Other objects and advantages of the invention will be apparent from the following description and claims, the novelty'consisting in the features of construction, combination of parts, the unique relations of the members and the relative "proportion-ing, disposition, and operation thereof, 'all'as more completely outlined herein and particularly pointed out in the appended claims.

Inthe drawings, which form part of the present specification Figure 1 is a longitudinal-vertical sectional view through my storage chamber;

Figure 2 is a perspective view of my storage chamber as seen from above;

Figure 3 is a slightly enlarged fragmentary lateral sectional view taken through the container along the line '3--3 of Figure 1';

Figure '4 is an elevational view of the back of the container showing the door leading to the "internal control panel where externalair and vacuum lines are connectedto service the unit;

Figure 5 is a fragmentary sectional view taken along the line -'5-5 in Figure '4, showing the door handle in side elevation;

Figure '6 is a fragmentary sectional view taken through the inner chamber along the line 6-'fi of Figure 4 and showing the vacuum line horizontally disposed along the inner chamber wall;

Figure '7 "is 'a front elevational View of a modified form of my storage chamber with the door p Figure 8 is an elevational view of one form of container door;

Figure 9 is -a sectional view through the doorlocking mechanism taken along the line as of Figure 8;

Figure 10 is an elevational view of a housing assembly employed to anchor and insulate "condu-its which pass through the walls of my containers;

Figure 11 is an axial sectional view through a conduit mounted in the housing of Figure 10 between two walls of a container;

Figure 12 is an axial sectional view taken through a conduit mounted in the housing 'assembly of Figure 10, showing the manner in'which the conduit passes through three walls of the container which are spaced apart and insulated from one another;

Figure 13 is a fragmentary sectional view taken along the line l3--'|'3 of Figure 14, showing the method of connecting a support between the inner walls of the container:

Figure 14 shows another modified form of my container illustrated in connection with a schematic layout of associated refrigerating, heating and evacuating apparatus;

Figure 15 is a vertical section taken through the rear wall of the container of Figure 7;

Figures 16 and 17 are elevational views of the end of the refrigeration coil housing of Figure 15, showing the split housing cover in closed and open positions, respectively;

Figure 18 is an enlarged fragmentary sectional view taken along the line l8l8 in Figure 15, showing the vacuum line and the manner in which it is carried through the chamber walls;

Figure 19 is an enlarged fragmentary view, in elevation, of the hinged door of Figure 14, showing the hinge mounting and the flexible conduit joining the interior of the hollow door to the evacuated wall of the container body;

Figure 20 is a fragmentary sectional view through the door of the container of Figure '7, taken along the axis of a locking rod and showing the arrangement of the locking wedge thereof;

Figure 21 is an elevational view, partially broken away, of the floating hinge assembly of Figure 19 with the hinge plate removed;

Figure 22 is a sectional view of the floating hinge taken along the line 22-22 of Figure 21;

Figure 23 is a sectional view taken along the line 2323 of Figure 19, showing the arrangement of the flexible vacuum conduit between the door and the container;

Figure 24 is a side elevational view of my quickdetachable coupling assembly;

Figure 25 is a side elevational view of a modified form of the collar of my coupling assembly; I Figure 26 is a longitudinal sectional view taken through the assembly of Figure 24; V Figure 27 is a transverse sectional View taken along the line 21-21 of Figure 24;

Figure 28 is a transverse sectional view taken through a wall of my container constructed of collapsible panels, particularly showing the interlocking edge construction of pairs of both insulating and hollow panels; I

Figure 29 is a sectional view taken alon the line 29-29 in Figure 28 through the locking edges of the hollow panels;

Figure 30 is a perspective view of an edge of one of the hollow interlocking panels of Figure 29; and

Figure 31 is a partially sectioned enlarged detail of the liquid injector of Figure 14.

' Figure 32 is a 'fragmental vertical sectional view taken thru the storage chamber of Figure 1, showing an additional pair of lines, 80a and 82a, for circulating heated and cooled air thru the innermost container 44. Figure 33 is a partial vertical sectional view taken' thru the container of Figure 14 showin the hot and cool air conduits provided with valve means for directing the respective air flow thru the storage space, the surrounding insulating chamber, or both.

Ligure 34 is an enlarged sectional view taken thru the valve means of Figure 33.

I'; has been found that many articles of food may be better preserved during shipping and storage by use of a vacuum, either alone or in association with temperature control of the perishable article By this means the necessity, for example, of freezing foodstuffs for future distribution may be obviated and a more palatable product obtained as Well, since vacuum preservation does not change the character of organic tissues; destroy vitamins or flavors, or remove minerals. However, use of my containers to obtain below freezing temperatures is also contemplated.

Further, a vacuum has a high insulating value so that its employment jointly with heating or cooling means permits the maintenance of a more uniform temperature within a container, which is valuable whether or not the perishable items are stored in the evacuated section or not. Since the optimum environment for preservation of foods and beverages of course differs widely from one article to another, the desired treatment afforded different items necessarily differs and consequently I have provided containers with diverse arrangements of heated, refrigerated, and evacuated storage spaces therein.

Thus, for example, potatoes which are being shipped through freezing territory would be carried in a heated chamber, while fish and meat could be maintained at below freezing temperatures. Again, a rarified or evacuated atmosphere maintained at above freezing temperature is particularly advantageous for the shipping of ripe, freshly picked fruits and berries.

As shown in Figure 1, there is provided a generally rectangular shipping and storage container 40, within which are nested an intermediate container 42 and a central food receptacle 44, each of the three containers having a door or

entrance

43, 48 and 58 at the same end so that entrance to the innermost receptacle is gained through the-successive doors.

The inner containers are spaced apart along their sides, top and bottom by a series of laterally spaced, non-metallic or insulating, longitudinal rails, 52 and 54, located between the respective compartments, each rail containing a series of lateral apertures 56 to allow passage of air therethrough, the individual rails having their top and bottom edges disposed in correspondin channels 51 formed in pairs of oppositely aligned supports 58 which are mounted along the adjacent container walls or may be formed integral therewith. The supports serve both to restrain the rails against lateral movement and to facilitate insertion of the successive inner containers within the outer ones. A correspondingly positioned series of skids 60 are additionally provided on the bottom of the outer container for ease in moving the same about a floor or the like.

Evacuation of air from food container 44 is efiected by a vacuum line 62, connected to an external vacuum pump (not shown) and controlled by an automatic pressure or vacuum switch in communication with the chamber by conduit 64. These lines, together with a Water injector 66 and thermostat 68 enter the storage chamber through an insulating block 69 mounted along the back wall thereof. The inner ends of the

members

62, 64, 66, and 68 are protected against contact with articles stored within the chamber by a perforated cover plate Hi. The vacuum line 62 may extend horizontally along the end and side walls of the chamber as shown in Figure 6 to serve also as a guard or bumper for the Walls, being provided with successive openings 63 to permit evacuation of air, such openings bein spaced so that if one or more becomes clogged by the pressure of an article against it, the others will still permit the line to function.

Intermediate container 42 is also penetrated with :a vacuum line 12 and vacuum gauge 274 as well .as :a pair of conduits l-'6 and 1.8 for circulating hot .or cold air through the chamber in response to the thermostatic control 68. .Asimilar pair of air conduits 8i and 82 (which may also be responsive to thermostat 68) are .provided for the outermost chamber, being disposed to penetrate a transverse insulating wall 84 disposed between containers 4i] and 42 .so as to separate the main air space st of the outer chamber from a rear chamber portion 83 thereof, within which rear portion the various conduits maybe coupledifrom time to time with externally extending lines .as described hereafter. .Access to control chamber 88 is by way of an inverted 1L-shaped closure 90, hinged to the outer container 48 by recessed hinges 92 and provided with :a suitabl recessed catch to engage the top of the container at '94. Aipair of similar catches 95 are lilcewise mounted on the front closure '45. .In addition 'to the :insulating 'eifect obtained :by the :air space 96 between the two inner, spaced containers, and that of outer air spaces 85 and 88, further insulation against heat transfer is obtained through the use of insulating material 92 such as asbestos, pumice, fiber glass, sawdust, cork, .etc.,'which fills the hollow walls of the outer shell 40.

For use in moving the container, a handle 1927 (Figures 45) :is provided at either end thereof, sunk within a recess 192 so as to .lie beneath the outer surface of the container wall, said handle being provided with an outwardly extending, engaging lug i I34 on either side thereof, so disposed as to abut against the face of the recess when the handle has been partly lifted, thereby avoiding crushing the fingers of the persons lifting it, as might otherwise happen if the handle were allowed to come up all the way.

Each of the

inner compartments

42 and 44 is provided at its front-end with an outwardly projecting flange 5B6 peripherally disposed about the aperture of the chamber, each flange having a groove I98 about its inner face adapted to be engaged by a plurality of locking wedges H mounted on the outer face of the

door

68 or 52!, so as to project beyond each edge thereof. Each of the locking wedges is 'disposedto move within a fixed guide collar H l, and i extended or retracted by means of :an operating wheel H2 terminally mounted upon :a threaded shaft H4 which in turn is journalled within .a centrally located, generally rectangular frame H6 located on the outer face .of the door, said :shaft being threaded also through the tapped aperture of a square-ended actuating tblock H8, which is contained within the frame. The block or coupling .8 is restrained against rotary movement by four :bell cranks, :each having a short arm l2il which extends into a corresponding recess formed in the adjacent side of the block. Each of the bell cranks is pivotally supported at I26 on :a bracket I28 formed on the inner surface of the housing H6 and has a long arm I22 extending generally parallel to the axis of the screw A44. The arms 122 are connected at their outer :ends to radially extending, slidably'supported locking arms Hi9 having wedge blocks H0 at their outer ends which engage the peripheral groove ills 'in the flange m to draw the door tightly against the doorway. By this construction, rotation of the operating wheel H12, causes the block M8 to travel up or down :along theshaft I i-4 as the case may be, causing each lever :arm I22 to slide its corresponding locking wedge I II] in .or out of the peripheral groove H18. In the alternative, the.

locking arms may be positioned :on the inner face of a door as in Figure 20, each wedge Ilfla engaging :a correspondingly aligned stop or .flange i129. Compressible Ke. g. rubber) gaskets 32 are arranged about the door edges.

The several conduits which pass through the walls are enclosed therein by insulating housing 69. Although the conduits are depicted in Figure 1 as vertically spaced within the housing, the latter may conveniently be horizontally disposed as shown in Figure 10. As seen particularly in Figure .11, such a block is formed of a main .body of non-metallic or insulating material 152 (for example, molded plastic) carrying a transverse conduit section I 54 to which a'pipe or similarattachment may be screw-threadedly attached. The chamber walls (42 and 44) are anchored to the block I52 by screws I56 which-also'engage a (cork or rubber) gasket I55 and a metallic reinforcing ring I59 peripherally mounted on the sirably formedin'several pieces for easy assembly, -as shown in Figure 12, and an outer .cover 151 may be molded integral therewith and provided with suitable openings L58 through which screws secure the outer wall to the housing.

In order to quickly connect and disconnect the several conduits entering the chamber, .to the corresponding external vacuum orzair lines, there is provided a novel coupling assembly, Figures fi l-27, consisting essentially of a blunt-ended, inwardly sloping conduit terminus section 220 adapted to have its end wedged against a zoomplementary obtuse, annular face 222 of .:a hose or pipe-end 224 by action of an independently :ro-

tatable collar 226 possessing an inwardly projecting flange 22'! which is adapted to be brought into registration with the .back of the outwardly extending annular face 222, said collar being designed to encircle jointly the ends of the conduit terminus 220 and pipe-end 224 and draw. the two together by reason of engagement of a pair of inwardly slanted bayonet :sloits 228 (formed on either side of the collar), with a pair of radially projecting studs L230 mounted on opposite sides of the conduit terminus. In order to lock the opposite pipe and conduit members .in this tightly engaged position, there is provided on the conduit terminus 22%} an outwardly extending annular flange 23! having a series :of .closely placed, radially alignednotches .232 adapted to be engaged by a latch 234 'swinginglytmounted .on a radially extending handle 2% of .the collar. In aimo'dified form of collar shown in Figure 25, instead of a handle, there is provided a generally annular neck formed integral with the body 5.2 26 and having an outer polygonal face 240 adapted to be engaged by a suitable wrench in order to elfe'ct rotation of the collar.

A modified form of my storage container is illustrated in Figures 7 and 15-18, this embodiment providing a vacuum storage container 242 disposed within a surrounding storage chamber 244, the temperature of the air in the latter being regulated by a refrigerating or cooling unit 245 and .a heating unit 248, each of which latter are bolted onto the back of the container and situated in a generally cylindrical external housing, 249 and 250 respectively, similarly attached to the back of the container. This particular location of the heating and cooling units is not specifi'ed by way of limitation however, since theseunits maybe located elsewhere within the con-" tainer as desired.

A split cover plate is provided for the outer ends of the

cylindrical housings

249 and 250, the upper plate I90 (Figures 16 and 17) having a'pair of pipe-receiving openings I88 formed along its inner edges as well as a pair of laterally spaced slots I92 and correspondingly shaped pair of ears I94 adapted to be received therein and held in such alignment by a latch I96 and pin I91.

Vacuum line I54a. is adapted to evacuate either the vacuum chamber 242 or the insulating space I91 which surrounds both the vacuum storage chamber 242 and the heated and cooled storage chamber 244, the line serving further to evacuate hollow door 252 through a flexible conduit as will be shortly described. The manner of carrying the vacuum line through the pair of container walls is shown in Figure 18, there being provided an externally threaded plug 254 formed of insulating material and adapted to receive the vacuum line through its center and to screwthreadedly engage a corresponding aperture in the outer container wall 256 so that upon insertion therein it will act to compact an annular plug 258 formed of compressible insulating material (for example rubber) surrounding the conduit and having its opposite face in abutment against inner insulating wall 250.

Inner walls

260 and 262 are held in spaced relation by means of lateral supports I64 which are secured to each adjacent wall by a bolt I68 (Figure 13) said supports being at the same time held from .direct'contact'with either the wall or the'bolts by means of a flat insulating washer I12 disposed on one side of the support, and on the opposite side by an insulating sleeve I14 having a terminal, outwardly flanged flat portion I15 adapted to be sandwiched between the two members. Thus, it will be seen that the container walls, supports and conduits may be formed of metal to insure strength but are restrained from heat conducting, metal-to-metal contact by such structures as the insulating

rails

52 and 54, the conduit housing block 69, the end insulating walls 84, the lateral support mountings I12 and I15, and the insulating structures of Figure 18.

Another modification of my container is illustrated .in Figures 14, 19 and 21-23, the container 40a being provided with an outwardly sloping doorway and a correspondingly wedge-shaped hollow door 460: which seats therein. One hinge plate I is attached to the sloping edge of the door in the conventional manner while its companionate hinge plate 132 is secured by suitable screws to a horizontally slidable block I34, normally urged to one side by a pair of coil springs I36 which are held in alignment therewith by a corresponding pair of centering pins I38 extending from the side of said block so as to form a partial core for each coil spring. The sliding block and springs are in turn retained within a recess in the sloping doorway by means of a cover plate I40 having a pair of horizontal slots I42 to permit passage of screws I44 which connect the hinge plate I82 to the sliding blocks. By this arrangement there is obtained a highly effective automatic centering of the inwardly slanted edges of the door within its sloping doorway as extension of the locking wedges IIO thus serves to force it into airtight alignment.

A further feature of the present construction is the provision of a hollow chamber within the door panel 46a which may be evacuated together with a vacuum chamber of the container, and to effectuate this, a flexible conduit I46 is provided to connect the door chamber with the body chamber, said conduit being adapted to lie in its collapsed position (that is, when the door is closed) within a complementary pair of corresponding recesses I48 and I50 formed respectively along the hinge edge of the door and the adjacent face of the container. A similar attachment is also provided between the hollow door 252 and the vacuum chamber I91 of the container of Figures 7 and 15'. A vacuum release valve I5I is also present on the several vacuum doors in order to permit entry of air to the inner chambers so as to facilitate opening the doors thereof.

A somewhat schematic arrangement of elements adapted to service my food containers is also shown in Figure 14;, there being provided a vacuum pump I98 responsive to automatic pressure switch I99, a heating coil 290 and a cooling unit composed of compressor 202 and condenser tubes 294 and evaporator tubes 205 for vaporization of liquified ammonia or other refrigerant. Air which has been warmed or cooled is circulated through conduits 82 and by electrically driven

fans

206 and 208 respectively, the heating and cooling systems both being operated by thermostatic control 20l.

Eachair conduit

88 and 82 contains a shut-off or damper 8I and 83 respectively, by means of which the air coming out of the chamber is by-passed around the heating or cooling unit as the case maybe, thus preventing, for example, exposure of air-cooling tube 205 to warm air moving out through conduit 80. An atomizer member 2I4 (Figure 31) is additionally provided for injecting water or other liquid into the food storage chamber from time to time in order to maintain the moisture content thereof or to supply a preservative spray as desired. Since the heating and refrigerating units as well as the atomizer, pressure switch and thermostatic control are of conventional design they will not be described in detail.

By still another modification, my vacuum container may be constructed from demountable interlocking panels (Figures 28-30). connected hollow panels I15 is sandwiched between outer panels I16 formed of insulating material, and the storage chamber thus formed and/or the hollow sections of the connected panels I15 may be evacuated or, in the alternative supplied with cooled or heated air as in the earlier described forms. The hollow panels are constructed with a longitudinal lip I18 eX- tending along an edge and arranged to overlie a complementary lip I19 of the adjoining panel, the lips being provided respectively with male I11 and female I80 guide members, designed to snugly engage each other and permit circulation or evacuation of air through passageways I83 which thus join the interiors of adjacent panels. The lips I18 and I19 are held in frictional engagement by screws inserted jointly through transverse, aligned channels I8I and I82 formed by cylindrical walls in the respective lips, the former channel being internally threaded, it being observed that both channels are open at either end but are at no place in communication with the hollow or vacuum sections of their panels. Analogous lip sections of the insulating panels I16 are strengthened by insertion therein of U-' shaped sleeves or braces I84 and are fastened together by suitable screws I86 therethrough.

While I have shown and described in some detail some presently preferred embodiments of my A lining of vacuum container, it is to be understood that various modifications may be made in the construction and operation thereof within the scope of the subsequently claimed invention.

The invention claimed is:

1. A container for preserving perishable goods including: a plurality of nested chambers each with its own closure, said chambers being spaced apart to form closed insulating space therebetween, the innermost of said chambers being adapted for use as a storage chamber and at least one of said chambers having an inwardly tapered wall forming an entrance thereto; a closure for said chamber having a complementary tapered wall adapted to frictionally engage the tapered wall of said chamber; a hinge assembly having one hinge plate secured to each of said tapered walls and adapted to lie in juxtaposition when the door is closed, one of said plates being adapted for limited movement along said tapered wall so as to permit self alignment of the closure Within said chamber entrance; locking means on said closure adapted to draw the same tightly against said closure entrance; means for selectively evacuating said storage chamber and said insulating space; and means adapted to circulate cooled or heated air selectively through said storage chamber and said insulating space.

2. A container for preserving perishable goods including: a plurality of nested chambers spaced apart to form a closed insulating space therebetween, at least one of said chambers being adapted for use as a storage chamber; means for evacuating at least one of said chambers; and other means for circulating temperature-controlled air thru said other chamber said last means being disposed, at least in part, within a tubular housing detachably connected to the outermost chamber, which housing is provided with a split cover plate formed with pipe receiving openings along its intersection and having looking means therefor, and corresponding projecting lugs and aligning slots formed along said intersection.

3. A container for preserving perishable goods including: a plurality of nested chambers each with its own closure and spaced apart to form closed insulating space between chambers, the innermost of said chambers being adapted for use as a storage chamber, longitudinal rails disposed between said nested chambers so as to space them apart, the rails being laterally separated from each other, provided with transverse apertures to allow passage of air therebetween within the closed insulating space, and being retained in complementary channels formed along opposing faces of the walls of adjacent chambers, and coupling means carried by each chamber for connection to external means adapted to evacuate and to circulate cooled or heated air selectively through said storage chamber and said insulating space.

4. A container for preserving perishable goods including: a plurality of nested chambers each with its own closure and spaced apart to form closed insulating space between chambers, the innermost of said chambers being adapted for use as a storage chamber, coupling means carried by each chamber for connection to external means adapted to evacuate and to circulate cooled or heated air selectively through said storage chamber and said insulating space, the outermost chamber of which is provided with longitudinally directed skid rails on its bottom and has a second closure adapted to give access to said coupling means carried by inner nested chambers, and the innermost chamber is provided with a Vacuum conduit extending around its inner sides so as to serve as well as a bumper guard for goods placed therein.

MOTTEL CLAR.

REFERENCES CITED The following references are of record in the:

file of this patent:

UNITED STATES PATENTS Number Name Date 450,373 Ott Apr. 14, 1891'. 643,358 Konold Feb. 13, 1900 877,987 Deschane et a1 Feb. 4, 1908- 1,054,578 Madison Feb. 25, 1913' 1,088,453 Roberts Feb. 24, 1914- 1,253,065 Looze Jan. 8, 1918 1,475,838 Lamb Nov. 27, 1923 1,848,440 Spitzenberger et a1. Mar. 8, 1932 1,859,613 Bailey May 24, 1932 1,873,838 Gebhard 1 Aug. 23, 1932' 1,948,587 Macready et al Feb. 27, 1934: 2,000,467 Lindseth May 7, 1935' 2,000,882 Comstock May 7, 1935 2,071,175 Philipp Feb. 16, 1937 2,102,225 Russell et a1 Dec. 14, 1937 2,147,026 Glab Feb. 14, 1939 2,345,204 Lodwig Mar. 28, 1944- 2,425,816 Maxson Aug. 19, 1947' FOREIGN PATENTS Number Country Date 4,612 Great Britain Nov. 29, 1876 17,802 Australia Acc. June 13, 1935