AU7200500A - Improved mullion assembly - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventors: Address for Service:

SEC

ORFORD PTY LTD o 104 'VT O^ Kerron James Martin lan Craig Otto CULLEN

CO.,

Patent Trade Mark Attorneys, 239 George Street, Brisbane, QId. 4000, Australia.

IMPROVED MULLION ASSEMBLY Invention Title: Details of Associated Provisional Applications: Australian Patent Application No.

PQ4595 filed 9 December 1999 The following statement is a full description of this invention, including the best method of performing it known to us: IMPROVED MULLION ASSEMBLY This invention relates to an improved mullion assembly. In particular, the invention is directed to a more thermally efficient mullion for a door mounting frame of a refrigerated cabinet, such as a commercial refrigerator or freezer.

BACKGROUND ART Refrigerated display cabinets, such as commercial refrigerators and freezers found in supermarkets and the like, generally comprise a plurality of insulated glass doors pivotally mounted on a door mounting frame.

The door mounting frame includes one or more mullions that extend vertically between the top and bottom perimeters of the frame to provide rigidity for the frame, and a sealing surface against which the swinging sides of the doors abut when closed.

15 Since a mullion provides rigidity to the door frame, and as it *must be able to withstand slamming of the doors, it is normally in the form of a strong metal structural frame member. Typically, the frame member is an aluminium extrusion. Aluminium frame members are not only highly heat conductive, but also non-magnetic. A steel sealing plate is normally fixed to 20 the front of the mullion to provide a magnetically attractive sealing surface against which a door-mounted magnetic gasket can seal.

0" The steel sealing plate normally extends across the width of the omullion. Thus, the vertical side edges of the sealing plate extend into the refrigerated space within the cabinet. The centre portion of the sealing plate is exposed to ambient air in the gap between adjacent doors. Since the sealing plate is a relatively good heat conductor, the centre portion of the sealing plate can be cooled to below the dew point temperature of the ambient air, resulting in the formation of condensation and/or frost on the surface of the sealing plate. This promotes the growth of mould, and rusting. It has therefore been the practice to electrically heat the sealing plate to maintain it above the dew point temperature of the ambient air, but such electrical heating increases the operating cost of the unit.

Various arrangements of insulating and conductive components have been used in mullion assemblies in order to overcome the abovementioned problem. Examples of mullion assemblies using insulating plastic components can be found in US patents 4330310, 4852303, 4941289 and 5035085, for example.

However, due to the need to provide a magnetically attractive sealing surface on the mullion, the known mullion assemblies still use a metal plate along their front face. Although the use of other plastic components and insulation in the mullion assembly, assists in maintaining the sealing plate above the dew point, it has been found that the sealing plate will still fall below the due point temperature from time to time, or in certain conditions.

It is an object of this invention to provide an improved mullion assembly for a refrigerated cabinet which overcomes or ameliorates the above described problem, or which at least provides the consumer with a 15 useful choice.

SUMMARY OF THE INVENTION In one broad form, this invention provides a mullion assembly for a door frame of a refrigerated cabinet, the mullion assembly comprising a post member, a vertical cover strip fitted along the front of the post member and forming the front face of the mullion against which a door of the cabinet i may seal, the cover strip being made of a material of low thermal conductivity, and at least one magnetically attractive member located between the post member and the cover strip for magnetic interaction with an associated magnetic strip on the door.

Preferably, the cover strip is made of thermally insulating plastics material. PVC or any other suitable plastics material may be used.

Since the cover strip is made of insulating material, thermal conductivity is reduced and the risk of condensation is largely eliminated at normal operating temperatures of the refrigerated cabinet.

Typically, the cover strip is a flexible clip-on strip which is removably attached to the post member.

The magnetically attractive member may be a steel strip.

Preferably however, the magnetically attractive member is a magnetic strip which provides stronger attraction to the magnetic strip in the door gasket.

Normally, two spaced parallel magnetic strips are located along the front of the post member behind the cover strip, for magnetic interaction with associated magnetic strips in gaskets of the respective doors which close against the mullion. As the cover strip is removably attached the post member, the magnetic strips can be easily accessed.

Heating wires may also be located between the post member and the insulating cover strip, if desired.

The post member is typically a C-shaped aluminium extrusion or the like. A rear plate may be fitted to the post member, spaced from the front 15 portion thereof to form a cavity. This cavity may be filled with insulation, such as expanded foam.

In some refrigerated cabinets, a fluorescent light or other strip lighting is provided at the back of the mullion for illuminating the contents of the cabinet. If mullion-mounted lighting is provided, the rear plate is preferably perforated or otherwise foraminous, and no insulating material is provided in the cavity between the rear plate and the front portion of the post member. In this manner, heat can travel from the light towards the front of the mullion, and used to heat the front face of the post and the cover strip.

Preferably, the ends of the mullion assembly slide or clip into end brackets fitted to the cabinet. The end mounting brackets not only provide a neat flush appearance, but also hide the entry points of heating wires and power wires for the lighting.

In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a refrigerated cabinet having a mullion assembly, Fig. 2 is a fragmentary exploded perspective view of the mullion assembly of the refrigerated cabinet of Fig. 1, Fig. 3 is a schematic section elevation of the mullion assembly of Fig. 1, Fig. 3a is an enlarged fragmentary sectional elevation of the mullion assembly, Fig. 4 is a sectional plan view of the front portion of the refrigerated cabinet of Fig. 1 having a mullion assembly with lighting, Fig. 5 is a sectional plan view of the front portion of the refrigerated cabinet having a mullion without lighting.

15 DESCRIPTION OF PREFERRED EMBODIMENT As shown in Fig. 1, a refrigerated cabinet 10, suitable for use as a commercial refrigerator or freezer, has frame 10OA on which a pair of glass :oo doors 11, 12 are mounted. The doors 11, 12 close against a central mullion assembly 13 mounted in the frame The mullion assembly 13 is shown in more detail in Fig. 2. The main structural component of the mullion assembly 13 is a post member 14 which is typically an aluminium extrusion.

A plastic cover strip 15 is snap-fitted to the front of the post. The cover strip is made from a suitable plastics material which is thermally insulating, i.e. of low thermal conductivity. Polyvinylchloride (PVC) may be used for the cover strip. C-shaped edges integrally moulded on the plastic strip 15 clip onto cooperating C-shaped formations extruded with the post extrusion 14.

The plastic strip 15 is detachably affixed to the front of the post 17. The engagement of the edges of the cover strip 15 with the post extrusion 14 is made secure enough such that a tool is required for removal of the cover strip. This deters unauthorised removal of the cover strip 15. However, 6 although a tool is required, a simple tool such as a screw driver is sufficient to lever the edges of the cover strip 15 out of engagement with the post extrusion 14.

The plastic strip is of low thermal conductivity and hence the centre thereof between the doors is not cooled to below dew point temperature.

A pair of magnetically attractive strips 16 are located between the post 14 and the cover strip 15. The strips 16 are suitably located in respective longitudinal recesses formed in the post extrusion. The strips 16 may be metal strips to which magnetic strips in the gaskets of doors 11, 12 are attracted when the doors are closed against the mullion assembly 13.

Preferably, the strips 16 are magnet strips to strengthen the magnetic attraction with the magnetic strips in the door-mounted gaskets.

If desired, heating wires can be provided between the post 14 15 and the cover strip 15. Groove formations 17 are extruded with the post 14 to provide recesses in which such heating wires can be located.

A rear plate 18 is provided between the free edges of the Cshaped post extrusion 14. The rear plate 18 is spaced from the front portion of the post 14, and the intermediate space may be filled with insulating material 20 (not shown) such as expanded foam. *on* In many applications, a fluorescent light will be mounted to the S.back of the mullion 13. Typically, a fluorescent light tube 20 is fitted to mounting brackets 19 fixed to the rear plate 18. A transparent or translucent light cover 21 is fitted to the post 19. (For this purpose, barb-shaped longitudinal edges on the light cover 21 locate in recess formations 14A extruded with the post 14 for this purpose).

If a light is provided at the back of the mullion assembly, perforations 22 are provided in the rear plate 18. The perforations 22 allow heat from the light 20 to pass forwardly to the front of the post extrusion 14 by convention and radiation. (No insulating material is provided in the post, thereby avoiding problems arising from foam leaks during the foaming process).

It has been found that in refrigerator applications, the heat from the light 20 is sufficient to maintain the front of the post extrusion 14, and the cover strip 15, above dew point temperature to eliminate condensation. For freezer applications, i.e. temperatures from OOC to -25°C, a single resistance style heater wire located in one or both of the recesses 17 is sufficient to eliminate condensation on the cover strip 15. The heater wires may also be used in environments of extreme humidity.

Plastic end shoes 23 are provided at the top and bottom of the mullion assembly 13 to ensure positive placement and fastening of the mullion assembly. The end shoes are fixed to the top and bottom of the cabinet frame. The plastic mounting brackets of the end shoes 23 simply slide onto and/or clip onto the ends of the mullion assembly, and provide a neat flush appearance to the whole mullion portion of the door frame. An aperture 24 in the end shoe 23 allows passage of the heating wires as well as the power wires to the light mounts 19, yet conceals the wire entry points through the cabinet. Thus, the heating and light wires are completely concealed within the mullion and cabinet.

o°.

°ooo The foregoing describes only one embodiment of the invention, and modifications which are obvious to those skilled in the art may be made thereto without departing from the scope of the invention as defined in the following claims. For example, although the invention has been described with particular reference to a post-type mullion assembly, the invention is also applicable, with suitable modification, to a mullion wall.

The term "comprising" or "comprises" as used in the appended claims is used in the inclusive sense to include the recited integers without necessarily excluding others.

Claims (13)

1. A mullion assembly for a door frame of a refrigerated cabinet, the mullion assembly comprising a post member, a vertical cover strip fitted along the front of the post member and forming the front face of the mullion against which a door of the cabinet may seal, the cover strip being made of a material of low thermal conductivity, and at least one magnetically attractive member located between the post member and the cover strip for magnetic interaction with an associated magnetic strip on the door.

2. A mullion assembly as claimed in claim 1, wherein the cover strip is a flexible clip-on strip made of plastics material which is removably *..*attached to the post member. 15

3. A mullion assembly as claimed in claim 1 or 2, wherein the magnetically attractive member is a magnetic strip extending longitudinally along the post member.

4. A mullion assembly as claimed in claim 1 or 2, wherein said at least one magnetically attractive member comprises two spaced parallel magnetic strips extending longitudinally along the post member, for magnetic interaction with an associated magnetic strip of a respective door of the cabinet.

5. A mullion assembly as claimed in any preceding claim, further comprising at least one heating wire located between the post member and the cover strip.

6. A mullion assembly as claimed in any preceding claim, wherein the post member is a generally C-shaped metal extrusion.

7. A mullion assembly as claimed in claim 6, further comprising a plate member fitted to the rear of the post member, and spaced from the front of the post member to form a cavity between the plate member and the front of the post member.

8. A mullion assembly as claimed in claim 7, wherein the cavity is filled with a thermally insulating material.

9. A mullion assembly as claimed in claim 7, further comprising an electrical light mounted to the rear of the plate member, the plate member having apertures therein.

A mullion assembly as claimed in any preceding claim, further comprising end brackets fitted to the ends of the post member, the end brackets having apertures therein for passage of electrical wiring.

11. A refrigerated cabinet having a door frame on which at least two doors are mounted, the door frame having a mullion assembly against which the two doors close, the mullion assembly comprising a post member having a front side, a vertical cover strip fitted along the front side of the post member, the cover strip being made of a plastics material and forming the .00. 15 front face of the mullion against which the doors of the cabinet may seal, and a pair of magnetically attractive strips located between the post member and the cover strip for magnetic interaction with an associated magnetic strip on a respective door.

12. A refrigerated cabinet having a mullion assembly comprising oo a post member having a front side, a vertical cover strip removably fitted to the front side of the post member, the cover strip being formed of a flexible plastics material, the cover strip forming the front face of the mullion assembly against which a door of the cabinet may seal, S25 at least one magnetically attractive member located between the post member and the cover strip for magnetic interaction with an associated magnetic strip on the door, and an elongate plate member fitted to the rear of the post member, and spaced from the front side thereof so as to form a cavity between the plate member and the front side of the post member.

13. A mullion assembly substantially as hereinbefore described with reference to the accompanying drawings. DATED this fourth y of December 2000 ORFORR 1PTY LTD 6 A~I 1 11 By their patent attorneysSE Ao Cullen Co. 0 *'Ole