AU713110B2 - Planter mulching cover - Google Patents

Description

WO 98/02032 PCT/CA97/00513 Planter Mulching Cover Field of Invention This invention relates to a device for discouraging weeds from growing in a planter. More specifically, it relates to a mulching cover for blocking light from reaching inside the planter.

Background Controlling weeds is a difficult but important task for growing plants. Nursery companies in particular consume large amounts of labour and toxic chemicals to discourage weeds from growing in their planters. Mulching is an advantageous alternative to manual weeding or chemical poisoning.

Mulching is the process of laying a bedding of opaque material over the soil surrounding a plant to block out the light that weeds need for photosynthesis. Traditional mulching materials such as straw, wood chips and peat moss also help plants by causing the surrounding soil to retain moisture and heat. However, traditional mulch is too easily displaced by erosion or animals.

As an alternative to natural mulches, opaque synthetic coverings have been used with some success. At the simplest level, the weekend gardener has for years laid garbage bags over a soil bed, slit holes in the bags, covered the bags with a thin layer of soil as an anchor and a disguise, and planted flowers through the slits. However, this tedious process is only appropriate for relatively small private gardens; the process and the results are SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 unsatisfactory for the commercial nurseryman. Over time the thin plastic tears and shifts; it begins to look ratty and allows light to pass through to the weeds below. These problems are exacerbated when trying to protect planters as opposed to garden beds. Many individual little pieces of plastic must be cut to the size and shape of the desired planters. The small pieces of plastic must be carefully hidden under soil to prevent them from blowing and comers are likely to creep above the soil ruining the appearance of the planter. The buried plastic is also likely to interfere with the proper flow of air and water which can be so difficult to achieve in planters.

Many prefabricated commercial mulch collars have been created to overcome some of the disadvantages of garbage bags. Examples of such mulch collars are taught in United States Patent number 5,058,317 granted to Lawrence J. McMurtrey on October 22, 1991 for a "Mulch Collar" and United States Patent number 5,085,001 granted to Michael S. Crawley on February 4, 1992 for a "Stabilized Mulch Skirt". Commercial mulch collars typically comprise a woven sheet of opaque material having a central aperture. A radial slot connects the central aperture to the outside perimeter of the sheet. In operation, the user opens the slot and draws it around the plant stem until the stem is encircled by the central aperture.

The user then closes up the slot and stakes the collar to the ground.

Commercial mulching collars are clearly an improvement over makeshift plastic garbage bags. They are easier to use in volume, they stay in place when staked, and they are less likely to rip because the slot and aperture are prefabricated into the weaving instead of being mere tears. However, these collars are poorly suited for use in a planter. The first problem is that lightweight sheets of such small size are prone to change position or blow 2 SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 away unless securely staked; however, inserting multiple stakes into a pot is labour intensive and may damage a plant's sensitive root system. Small stakes are also liable to injure people, to fall out of the planter, and to become lost. The second problem is that such covers make watering the complete soil area difficult unless the cover is removed during watering or the central aperture is of such a large diameter that it permits light to pass through to weeds below. The third problem is that a cover resting on soil might encourage the growth of mould by sealing in moisture and restricting air flow.

Covers for planters do exist; however, they are designed for other purposes and therefore suffer certain disadvantages when used for mulching. For example, United States Patent number 4,995,192 granted to Richard DeWild for a "Soil Cover for Potted or In-Ground Plants" and United States Patent Number 5,184,421 granted to Stephen W. Meharg on February 9, 1993 for a "Locking Cover for Pots" teach covers that are designed to keep the soil from spilling out of the planter and to keep children and animals out of the soil.

Typically, these sorts of covers comprise a barrier that covers the planter opening to retain the soil, a mechanism for securing the cover to the planter, and a relatively large central aperture in the barrier through which the plant stem passes. Because the cover is made of a plastic rigid enough to restrain soil and animals, the central aperture must be large enough that the cover doesn't damage delicate plant stems. In order to encourage proper ventilation and watering throughout the planter, supplementary holes are often distributed through the cover.

3 SUBSTITUTE SHEET (RULE 26) ii(~~l WO 98/02032 PCT/CA97/00513 What is needed is a mulching cover adapted specifically for a planter. The mulching cover should block light from entering the planter without unduly restricting air and water flow.

It should adapt to multiple planter sizes and to plants having multiple stems.

Summary The present invention is directed to such a device. According to one aspect of the invention, there is provided a mulching cover for a planter, the planter having a rim that defines an aperture through which a plant may grow, comprising: an iris-type diaphragm adapted to cover a first region of the planter aperture, thereby casting a first projection in the plane of the aperture, a collar, engaging a portion of the perimeter of the diaphragm, adapted to cover a second region of the planter aperture, thereby casting a second projection in the plane of the aperture, and means for securing the collar to the planter.

The first projection and the second projection may form a union that substantially equals the whole of the planter aperture. The diaphragm may be opaque and made of resilient plastic. The securing means may be a groove circumscribing the collar and adapted to engage the rim of the planter. The iris-type diaphragm may comprise a plurality of leaves extending radially inward from the collar and the leaves may be carved from a unitary sheet of plastic.

Each of the leaves may comprise: a tip, a first edge, a second edge obliquely opposing the first edge and meeting the first edge at the tip, and third edge obliquely opposing the first edge and the second edge and engaging the collar. Each leaf tip may be rounded. Each pair of adjacent leaves may define a slot between the first edge of the first leaf and the second 4 SUBSTITUTE SHEET (RULE 26) -I-~~iii?---lli WO 98/02032 PCT/CA97/00513 edge of the second leaf and the slot may extend radially from the first leafs tip toward its third edge. In some cases, the slot may intersect the third edge. The collar and the diaphragm may define a substantially radial breach. The leaves may be free to move normally to the plane defined by the diaphragm.

According to a second aspect of the invention, there is provide a method of providing mulching for a planter, the planter having a rim that defines an aperture through which a plant may grow, comprising: covering a first region of the planter aperture with an iris-type diaphragm, covering a second region of the planter aperture with a collar that engages a portion of the perimeter of the diaphragm, and securing the collar to the planter.

Brief Description of the Drawings These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where: Figure 1 is a perspective top view of a planter mulching cover tunrolled into its fully open position and embodying one aspect of the invention, Figure 2 is a perspective top view of the planter mulching cover of Figure 1 in an intermediate position, and Figure 3 is a perspective top view of the planter mulching cover of Figure 1 rolled-up into its fully closed position Description SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCTICA97/00513 With reference now to Figure 1, a planter mulching cover is generally illustrated at 100.

The cover 100 is adjacent a planter 200, not part of the invention, that defines an aperture 210 circumscribed by a rim 220. A plant 300, not part of the invention, having a stem 310 grows within the planter 200 extending through the aperture 210.

The mulching cover 100 comprises an iris-type diaphragm generally illustrated at 120 and a mounting mechanism generally illustrated at 160.

The iris-type diaphragm 120 comprises a plurality of leaves 122 extending radially inward from a circumscribing collar 124. The leaves 122 are preferably carved from a unitary sheet of plastic and the plastic is preferably very soft, thin, resilient, and opaque. Opacity is desired to block light from passing through the aperture 210 of the planter 200. Resiliency is desired to permit the leaves 122 to engage in the relative movement typical of an iris-type diaphragm. Softness and thinness are desired so that the delicate plant stem 210 is less likely to be injured by the diaphragm leaves 122. The collar 124 is preferably made from resilient plastic to permit the leaves 122 to engage in the relative movement typical of an iris-type diaphragm.

Each leaf 122 has a tip 126, a first edge 128, a second edge 130 obliquely opposing the first edge 128 and meeting the first edge 128 at the tip 126, and third edge 132 obliquely opposing the first edge 128 and the second edge 130 and engaging the collar 124. Each tip 126 is rounded as further protection for the plant stem 210.

6 SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 For each pair of adjacent leaves 122 a slot 134 is defined between the first edge 128 of the first leaf 122 and the second edge 130 of the second leaf 122. Each slot 134 extends generally radially from the leafs 122 tip 126 toward its third edge 132. The slot 134 need not extend fully to intersect the third edge 132, extending only so far as required to facilitate the desired relative movement typical of an iris-type diaphragm; however, a breaching slot 134a extends past the third edge 132 of each adjacent leaf 122 to breach the collar 124, thereby permitting the collar 124 and therefore the diaphragm 120 to be opened and closed.

With reference now to Figures 1, 2 and 3, the configuration of the diaphragm 120 is more clearly illustrated as the cover 100 is rolled-up and unrolled at the breaching slot 134a.

When the cover 100 is at least partially unrolled (Figures the diaphragm 120 is open and the leaf 122 tips 126 define between them a central aperture 136. The size of the central aperture 136 can be calibrated to the radius of the collar 124 and thereby the planter 200 to take advantage of the assumption that a larger planter 200 will often contain a larger plant 300. As the cover 100 is rolled-up and the radius of the collar 124 is reduced, the leaves 122 are forced together, thereby narrowing the slots 134, (Figure 2) until the first edge 128 of one leaf 122 begins to overlaps the second edge 130 of an adjacent leaf 122, thereby narrowing the slots 134. When the radius of the collar 124 is sufficiently reduced (Figure the central aperture 136 is completely closed and the slots 134 are completely closed as well. The fully closed cover 100 is advantageously used for storing uncontaminated soil in planters in preparation for planting.

It must be emphasized that the iris-type diaphragm 120 differs from a conventional camera diaphragm in one very important respect. Unlike a camera diaphragm, the leaves 122 are 7 SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 free to move normally to the diaphragm 120 plane. As the leaves 122 are forced to move away from the diaphragm 120 plane, the radius of the central aperture 136 increases. As the leaves 122 resiliently move toward the diaphragm 120 plane, the radius of the central aperture 136 decreases.

The mounting mechanism 160 comprises a circumscribing groove 162 which follows the perimeter of the collar 124 and is adapted to engage the rim 210 of the planter 200.

However, other methods of mounting the diaphragm 120 to the planter 200 are suitable and contemplated. For example, the diaphragm 120 could be press fit into the planter 200. The diaphragm 120 could be chemically bonded to the planter 200. The diaphragm 120 and the planter 200 could even be formed as an integral whole.

It should be observed in the preferred embodiment illustrated that the diaphragm 120 is both concave and recessed below the rim 210 of the planter 200. This configuration is advantageous in that it permits a nurseryman to simultaneously carry a number of planters 200 by their rims 210 without having to first remove the mulching covers 100.

In operation, the user unrolls the collar 124 of the mulching cover 100, thereby forcing open the breaching slot 134a. The user feeds the breaching slot 134a around and over the stem 310 of the plant 300 until the stem 310 is positioned in the central aperture 136. He then rolls-up the collar 124, thereby closing the diaphragm 120 around the stem 310, and seals the mulching cover 100 over the aperture 210 of the planter 200 by engaging the rim 220 of the planter 200 with the groove 162 of the cover 100.

SUBSTITUTE SHEET(RULE 26) SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 Rolling the cover 100 to fit the planter 200 is likely to set the correct size range for the aperture 13 6 to fit the plant stem 3 10 because larger planters 200 are generally used to hold larger plants 300. However, a fine adjustment of the aperture 136 to fit the plant stem 310 is made by moving the diaphragm 120 leaves 122 toward or away from the diaphragm plane. When in place, the cover 100 restricts light from entering the aperture 210 of the planter 200 but does not unduly interfere with air flow or watering because the slots 134 allow both air and water to pass through.

When the diaphragm 120 leaves 122 smoothly engage the stem 3 10 of the plant 3 00, they encourage the stem 3 10 toward the centre of the planter 200. As the plant 300 grows, the stem 3 10 presses against the diaphragm- 120 leaves 122 to expand the central aperture 13 6 as needed. It should be observed that plants having multiple stems can be more easily accommodated by this iris-type diaphragm 120 structure than by a rigid cover with a fixed central aperture. For a conventional rigid cover to accommodate multiple stems with room for growth, the central aperture would have to be made so large that it could not effectively block out light or encourage the stems toward the center of the planter 200.

It should be observed that the mulching cover 100, while flexible, can be manufactured to be durable as well such that it can be reused with successive plants and planters.

Although a specific embodiment of the present invention has been described and illustrated, the present invention is not limited to the features of this embodiment, but includes all variations and modifications within the scope of the claims.

9 SUBSTITUTE SHEET (RULE 26) I: WO 98/02032 PCT/CA97/00513 For example, it is contemplated that the slots can have both a radial and a tangential component.

It is also contemplated that the perimeter of the collar 124 need not define a circle. The circular geometry is preferable because it allows a single cover 100 to fit different planter sizes; however, it would also be possible to build a non-circular cover 100 that would fit a single size of planter.

It is also contemplated that the diaphragm 120 need not cover the whole planter aperture 210, but merely a specific region. It is also contemplated that one cover 100 could contain a plurality of diaphragms 120.

Although the breaching slot 134a aids the user to insert the stem 310 into the diaphragm 120, it is contemplated that the breaching slot 134a could be omitted for use with smaller plants 300 where the stem 310 would be directly inserted into the central aperture 136 of the diaphragm 120.

SUBSTITUTE SHEET (RULE 26)

Claims (15)

1. A mulching cover for a planter, the planter having a rim that defines an aperture through which a plant may grow, comprising: an iris-type diaphragm adapted to cover a first region of the planter aperture, thereby casting a first projection in the plane of the aperture, a collar, engaging a portion of the perimeter of the diaphragm, adapted to cover a second region of the planter aperture, thereby casting a second projection in the plane of the aperture, and means for securing the collar to the planter.

2. A mulching cover as in Claim 1, wherein the first projection and the second projection form a union that substantially equals the whole of the planter aperture.

3. A mulching cover as in Claim 2, wherein said diaphragm is opaque.

4. A mulching cover as in Claim 3, wherein said diaphragm is made of resilient plastic.

A mulching cover as in Claim 4 wherein the securing means is a groove circumscribing said collar and adapted to engage the rim of the planter.

6. A mulching cover as in Claim 5 wherein said iris-type diaphragm comprises a plurality of leaves extending radially inward from the collar.

7. A mulching cover as in Claim 6, wherein said leaves are carved from a unitary sheet of plastic.

8. A mulching cover as in Claim 7, wherein each of said leaves comprises: a tip, a first edge, 11 SUBSTITUTE SHEET (RULE 26) WO 98/02032 PCT/CA97/00513 a second edge obliquely opposing the first edge and meeting the first edge at the tip, and third edge obliquely opposing the first edge and the second edge and engaging the collar.

9. A mulching cover as in Claim 8 wherein each tip is rounded.

A mulching cover as in Claim 9 wherein each pair of adjacent leaves defines a slot between the first edge of the first leaf and the second edge of the second leaf.

11. A mulching cover as in Claim 10 wherein the slot extends radially from the first leafs tip toward its third edge.

12. A mulching cover as in Claim 11 wherein the slot intersects the third edge.

13. A mulching cover as in Claim 12 wherein the leaves are free to move normally to the plane defined by the diaphragm.

14. A mulching cover as in Claim 14, wherein said collar and said diaphragm define a substantially radial breach.

15. A method of providing mulching for a planter, the planter having a rim that defines an aperture through which a plant may grow, comprising: covering a first region of the planter aperture with an iris-type diaphragm, covering a second region of the planter aperture with a collar that engages a portion of the perimeter of the diaphragm, and securing the collar to the planter. 12 SUBSTITUTE SHEET (RULE 26)