TECHNICAL FIELD

The present invention relates to improvements in and relating to access doors. The invention has particular application to doors for accessing the workings of machinery or the like.

BACKGROUND ART

Providing access to the workings of machines is important for maintenance, inspection and cleaning.

One machine that requires regular inspection and cleaning is a produce cleaning machine, such as a commercial vegetable polisher. The inner workings of such machines include a rotating frame supporting rotating brushes. In use the rotating frame and brushes transport produce through the machine as well as cleaning dirt and the like from the external surfaces of the produce. This action results in a large amount of dirt being thrown around the internal surfaces of the machine. It is common for an opening to be provided in the side of such machines to allow for cleaning and maintenance, such as brush replacement, to be performed. In use this opening must be closed off to protect operators from the rotating frame and brushes. Closing the opening also contains dirt and wash fluids within the machine.

Often machines of this type are supported above the ground and therefore are normally accessed by relatively narrow walkways. The presence of a walkway limits the ability to provide access doors that swing outwards. For this reason most machines of this type will include two or more sliding doors. Generally two overlapping sliding doors are used, one to cover each half of the opening. When access is required to the opening one of the doors is slid across the other to provide access to half the opening. Once cleaning or maintenance is completed on that half the doors are slid to the opposite side of the opening and the other half of the opening can be accessed. Other types of doors such as gull wing and vertically sliding doors have been used; however these each exhibit the same problem.

Because the inner surface of the access doors provides the inner surface to the machine, they become covered by dirt during use. The problem this creates is that it is very difficult to clean the backs of the doors. With sliding doors each half is cleaned by leaning into the machine and hosing the back of the door that is accessible. Vertically sliding doors present even more of a problem as the door back is not so simply accessed. Furthermore, simply hosing the back of the door results in the dirt being washed off the inside of the door onto the outside of the machine, the walkway and the general area around the machine, which is not desirable. Furthermore, while the access doors can be opened for normal cleaning, and some

maintenance, full access to the machine opening for comprehensive maintenance can require the door to be removed entirely. This can take a significant amount of time as well as creating difficulty for the maintenance staff in the handling of very large and heavy doors and/or panels. It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise", or variations thereof such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. DISCLOSURE OF THE INVENTION

According to a first aspect of the present invention there is provided an access door for covering an opening, the opening including a left hand frame member and a right hand frame member on opposite sides thereof, the access door including: a first door pivotably attached to the left hand side frame member and the right hand side frame member so as to be rotatable along a width of the opening between an open position and a closed position; a second door pivotably attached to both the left hand side frame member and the right hand side frame member so as to be rotatable along a width of the opening between an open position and a closed position; wherein the first door is configured to cover a first portion of the opening and the second door is configured to cover the remainder of the opening and overlap a portion of the first door, and wherein the doors rotate in opposite directions to one another.

According to a second aspect of the present invention there is provided a vegetable polishing machine including a side opening for servicing and cleaning an internal space, the side opening including a left hand frame member and a right hand frame member on opposite sides thereof, an access door positioned in the side opening including an upper door pivotably attached to the left hand side frame member and the right hand side frame member along an upper edge of the upper door so as to be rotatable along a width of the opening between an open position and a closed position; a second door pivotably attached to both the left hand side frame member and the right hand side frame member along a lower edge of the lower door so as to be rotatable along a width of the opening between an open position and a closed position, wherein the first door is configured to cover a first portion of the opening and the second door is configured to cover a second portion of the opening as well as part of the first portion, and wherein the doors counter-rotate relative to each other.

Preferably the opening is provided in a side of a machine, wherein the first door is an upper door and the second door is a lower door.

In preferred embodiments an edge of the lower door overlaps an adjacent edge of the upper door when the doors are in the closed position. The overlapping of the upper door by the lower door prevents fluids and debris from escaping from inside the machine between the first door and the second door. By overlapping the upper door with the lower door any fluids or debris running down the inner surface of the upper door run onto the lower door and are thereby prevented from escaping between the doors.

The degree of overlap varies depending on the direction of any sprayed fluid or debris; for example, if the fluid or debris are spayed upwards towards the upper door a larger overlap may be required to prevent fluids from escaping through the overlapped portion of the upper door and the lower door. If however the fluid or debris are spayed downwards a smaller overlap may be satisfactory. The size of the overlap between the doors should therefore not be seen as being limiting. In preferred embodiments the overlap is in the range from 90 mm to 70 mm. Preferably the overlap is 80 mm.

With this amount of overlap the geometry of the doors may be chosen so that the two overlapping portions of the doors when closed do not need to touch one another in order to contain the spray. In preferred embodiments the two overlapping portions of the doors when closed are separated by a gap in the range from 5 mm to 10 mm. Preferably the gap is 10 mm.

This may be an important safety consideration for an operator as it may remove the likelihood of a pinch point when opening or closing the doors.

In preferred embodiments the doors are configured to each cover substantially half of the opening and open outward and away from the opening. By having each door substantially equivalent to one half of the size of the opening the extent to which the doors swing out from the opening is minimized.

It should however be appreciated that the door size may vary between the first door and the second door. For example, in some cases it may be advantageous to have a larger upper door in order to reduce the extent the lower door extends outwards from the machine. This may allow an operator to stand closer to the machine to more conveniently access the opening and therefore the machine internals. In other embodiments a smaller upper door may be useful as this provides a greater ability for the lower door to capture and redirect fluids and debris that may fall from the upper door when open. In a preferred embodiment the size of the upper door is substantially the same as the size of the lower door.

In a preferred embodiment the weight of the upper door is substantially the same as the weight of the lower door.

In preferred embodiments the doors are counterweighted. Counterweighting the doors offsets a portion of the weight of the doors making it easier for an operator to open and close the doors in a controlled manner.

In some preferred embodiments the second door may be counterweighted against the weight of the first door. In embodiments where the first door is an upper door that opens by swinging upwardly and the second door is a lower door that opens by swinging downwardly, the weight of the second door, which is aided by gravity, can be countered against the upper door, which needs to open against gravity.

In addition to countering the doors against one another it may also be preferable to add an additional counterweight, especially in cases whereby the weight of a lower door is not sufficient to substantially overcome the force required to open the upper door. In preferred embodiments the upper door and the lower door are linked so as to rotate in unison.

Preferably the upper door and the lower door are countered against each other by a chain and sprocket arrangement. Preferably the chain rotates in a figure 8 pattern.

In preferred embodiments the lower door is configured to rotate through relatively less of an angle than the upper door when rotating in unison. In such embodiments the upper door will preferably be operable to a position in which the upper door is angled upwardly and an inner face of the upper door is directed away from the opening and the lower door is rotated to extend the door outwardly from the opening but whereby an inner face of the lower door slopes toward the opening. Preferably the chain and sprocket arrangement includes a sprocket associated with the lower door that has fewer teeth on it than a sprocket associated with the upper door, thereby resulting in greater rotation of the upper door relative to the lower door.

In a preferred embodiment the upper door rotates through an angle in the range from 60° to 65°. Preferably the upper door rotates through 62°.

In a preferred embodiment the lower door rotates through an angle in the range from 60° to 65°. Preferably the lower door rotates through 62°.

In a preferred embodiment the bottom door, when closed, is oriented substantially vertically, i.e. substantially 90 degrees to a horizontal plane. In a preferred embodiment the top door, when closed, is oriented to an angle in the range of substantially 260 to 300 degrees to the horizontal. Preferably the top door, when closed, is oriented to an angle of 279 degrees to the horizontal.

Preferably the lower door extends transversely away from the opening to a greater distance than the upper door. It will be appreciated that in the arrangement described any fluid and debris washed or scrapped from the upper door's inner surface will fall downwardly onto the inner surface of the lower door to be re-directed into a base of the machine.

In some embodiments the upper door may be pivotably attached to the left hand side frame member and the right hand side frame member by a support frame, and wherein a panel of the door is pivotably attached to the support frame about a further pivot axis along a width of the panel.

By providing a further pivot axis along a width of the panel the upper door can be rotated to a more convenient position for washing and may also be positioned to allow for a greater overlap with the open lower door. Providing a greater overlap with the lower door reduces the likelihood of fluid or debris from missing the lower door and not being redirected into the opening. Preferably the further pivot axis is positioned towards the middle of the panel.

Preferred embodiments of the present invention may provide a number of advantages, including: providing a compact opening access door for opening outwards into a walkway; providing an access door that provides substantially full access to an opening; providing an overlapping inner surface that prevents dirt and fluids from leaking from the inside of the machine during operation; • provides a lower door that serves as a guide for catching wash off from the upper door and inner machine and directing that wash off back into a base of the machine;

• providing a large door that can be opened and closed with low effort;

• providing an access door that provides easy access to the backs of the doors to allow dirt or the like to be cleaned from the backs of the doors; and

• an access door that may create a safeguard from moving parts inside the machine. BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of a prior art vegetable polishing installation;

Figure 2 shows perspective view of a prior art vegetable polishing machine;

Figure 3 shows a perspective view of a vegetable polishing machine having an access door in accordance with the present invention with the door in a closed position; Figure 4 shows a perspective view of the vegetable polishing machine of Figure 3 with the access door in a closed position;

Figure 5 shows a detail view of an access door in accordance with the present invention, with the access door in an open position;

Figure 6 shows the detail view of Figure 5 with the access door in a closed position; Figures 7a to 7d show cross sectional views of the access door in a number of different positions, and

Figure 8 shows a cross sectional view of a further variant of an access door in accordance with the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION The present invention relates to an access door for a machine, in particular a vegetable polisher. Whilst the access door should not be limited to such use the advantages of the door are clearly described with reference to this type of machine. Therefore, for clarity of explanation the present invention will be described with reference solely to a vegetable polishing machine.

With reference to Figure 1 there is shown a typical prior art vegetable polishing installation as generally indicated by designator 1. Figure 2 shows a detailed view of the vegetable polishing machine 2 in isolation of the other components of the installation. As shown in Figure 1 the vegetable polishing machine 2 is typically located above a catch tank 3. In use the catch tank 3 captures water and debris, such as dirt and plant matter, that is washed from the vegetables being polished (not shown). Due to the elevation of the vegetable polishing machine 2 an accessway 4 is provided in order for the vegetable polishing machine 2 to be inspected and serviced. The vegetable polishing machine 2 will typically house a drum 2a formed from a plurality of rotating cylindrical brushes 2b. In use the drum rotates in a first direction and the brushes rotate in an opposite direction. This action results in water and fluid being sprayed around the inside of the vegetable polishing machine 2. For this reason vegetable polishing machines are provided with access panels to allow cleaning and inspection of the machine insides. Cleaning is typically performed by water being sprayed into the machine onto the drum, brushes and internal surfaces. Any water and debris washed free falls into the catch tank 3 and is thereby contained. The vegetable polishing machine 2 of Figure 1 includes sliding doors 5, of which one is shown as being slid behind the other, this provides the advantage whereby the accessway 4 is not impeded by the doors, however the backs of the door are inconvenient to clean.

With respect to Figures 3 and 4 there is shown a vegetable polishing machine 6. It will be appreciated that the vegetable polishing machine 6 of Figure 3 and 4 directly replaces the vegetable polishing machine 2 shown in Figures 1 and 2.

The vegetable polishing machine 6 shown in Figures 3 and 4 includes an access door 7. The access door 7 is positioned over an opening 8, the opening defined by a left hand frame member 9 and a right hand frame member 10. An upper first door 11 and lower second door 12 are pivotably attached between the left hand side frame member 9 and the right hand side frame member 10. The upper door 11 and lower door 12 are configured to rotate in opposite directions to each other along a width of the opening between an open position, shown in figure 3, and a closed position, shown in figure 4.

In use the upper door 11 is configured to cover a first upper portion of the opening and the lower door 12 is configured to cover the remaining lower portion of the opening and to overlap 13 a portion of the upper door 11 when the doors are in the closed position shown in Figure 3. The upper door 11 and lower door 12 each cover roughly half of the opening 8. Overlapping of the upper door 11 by the lower door 12 prevents fluids and debris that are flicked by the rotating drum and cylindrical brushes during use from escaping through the doors.

Referring now to the detail views of Figures 5, 6 and 7a - 7d it can be seen that the upper door 11 and lower door 12 are counterweighted against each other by way of a chain 14 and sprocket 15a, 15b arrangement. Chain 14 forms a figure 8, this allows the upper sprocket 15a to rotate in the opposite direction to lower sprocket 15b and provide a counter rotating action to the upper door 11 and the lower door 12. The weight of the lower door 12 is transferred through the lower sprocket 15b, through the chain 14 to the upper sprocket 15a, in this manner the weight of the lower door 12 opening with the aid of gravity is offset against the weight of the upper door 11 which must open in opposition to gravity. Figures 7a - 7d illustrate a number of variations in the door positions. Figure 7a shows the doors in a closed position with the lower door 12 overlapping the upper door 1 . In the closed position the lower door latches into locking mechanism 16 thereby locking both the upper door 11 and lower door 12 in the locked position. When the doors are in the closed position they also disable an interlock which otherwise prevents the machine from running. This prevents access to the machine internals whilst the machine is running. Figure 7b illustrates the upper door 11 and the lower door 12 in a partially open position whereby the inner face 17 of the upper door 11 and the inner face 18 of the lower door 12 are accessible and can be washed down. It will be appreciated that whilst in this position any fluids and debris dropping from the inner face 17 of the upper door 11 falls onto and is caught on the inner face 18 of the lower door 12. The reverse slope of the lower doors directs the captured fluid and debris back into the machine where it falls into the catch tank 3, shown in Figure 1. Figure 7c shows the doors in a fully open position in which the operator is able to easily access the inside of the machine.

Figure 7d shows a further variant in which the upper door 11 rotates through a greater angle than the lower door 12. This provides improved access to the inner face 17 of the upper door 11 for cleaning, but still positions the lower door 12 so that fluids and debris dropping from the inner face 17 of the upper door 11 falls onto and is caught on the inner face 18 of the lower door 12. In such an embodiment additional teeth are added on the upper sprocket 15a

compared to the number of teeth on the lower sprocket 15b.

Figure 8 shows an additional variant in which the upper door 11 is provided with a further pivot axis 19 that passes through the upper door bracket 21 and upper door panel 20. The further pivot axis 19 allows the upper door panel 20 to be rotated independently of the lower door 12. This allows the upper door panel 20 to be rotated into a cleaning position where the inner face 17 of the upper door 11 is directed away from the opening and easily cleaned whilst the lower door 12 is positioned so that fluids and debris dropping from the inner face 17 of the upper door 11 falls onto and is caught on the inner face 18 of the lower door 12.

When the upper door of the variant shown in Figure 8 is returned to its normal position the upper door 11 and lower door 12 can be rotated into the same fully open position as shown in Figure 7c allowing substantially unimpeded access to the inside of the machine.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.