NL2027522B1 - Adaptive pipe cap - Google Patents

Abstract

A cap includes a lid, a stem extending from the lid, and a plurality of resilient holding members extending radially from the stem to at least the perimeter of the lid. 5 The stem section cross-sectional area is less than 70% of the lid area. Such a cap can easily and securely close off the end of a pipe or tube by the stem and holding members extending inside the pipe with the holding members biasing against the inside of the pipe to secure the lid over the end of the pipe. 10

Description

ADAPTIVE PIPE CAP The present disclosure relates to caps for cylindrical openings such as but not limited to pipes or containers.

BACKGROUND Pipes are often sealed or closed off at the ends when not in use or during transport to prevent detritus from entering the pipe cavity. Typically the sealing is performed by a purpose made cap that fits only one inner diameter size. Similar devices are used for sealing containers and other cylindrical openings against the entry of detritus.

Various caps are used for the purpose of sealing pipes. For example, conventional pipe caps may comprise horizontal flanges of elastic material around a central part which is substantially similar to the pipe inner diameter, with the flanges providing sufficient friction to keep the cap in place within the tube. Such caps only fit in pipes of one size, for example as disclosed in Japanese patent application JPHO425696A . A further example of a variation of such a cap is disclosed in Japanese patent application JPH09126386 wherein inner attaching parts extend from a square base part in the manner of flanges. Some elastic pipe caps can be stretched around the outer circumference of the pipe opening. An example of such a cap is disclosed in US patent US8646488B1.

SUMMARY OF THE INVENTION Aspects of the present invention are set out in the accompanying independent and dependent claims. Combinations of features from the dependent claims may be combined with features of the independent claims as appropriate and not merely as explicitly set out in the claims.

According to a first aspect of the present invention, a cap comprises a lid, a stem extending from the lid, and a plurality of resilient holding members extending radially from the stem to at least the perimeter of the lid and being contractable. The stem cross-sectional area is at most 70% of the lid area, optionally 60%, further optionally 50%, even further optionally 25 %.

Such a cap can be used to cover or close the end of a pipe, tube or other hollow member. This can be a temporary cover, for example, for storage and/or transport to ensure nothing enters the pipe. The lid could be a planar extension with an outer edge similar to the outer edge of the pipe (such that it fully covers the pipe opening), and could be, for example, circular, square, triangular, polygonal or rectangular or any other cross-sectional shape of the hollow elongated member. The stem can extend substantially perpendicular to the lid, and can be a variety of shapes, including but not limited to cylindrical, square, triangular, polygonal or rectangular. The stem could be hollow or filled, and can vary in shape, dimensions or size.

As the holding members extend from the stem to at least the perimeter of the lid and the stem cross-sectional area is at most 70% of the lid, an advantage of the pipe cap is that it can be used with multiple pipe sizes. A single cap may fit, for example, 3-4 pipe inner diameters. The holding members are suitably contractable without breaking to secure the lid to an end of a pipe, with the stem and holding members extending inside the pipe. The holding members are biased inwardly to fit within the pipe, and then return to their initial position, securing the cap to the pipe by providing a radially extending contact pressure against the interior of a pipe or opening. The holding members provide resilient holding force inside the pipe while the lid is located at an outside of the end of the pipe to close the opening. Because the stem is at most 70% of the area of the lid, and the holding members extend outwardly from the stem, the holding members can contract elastically when in use such that they can provide a sufficient holding force in various pipe inner diameters (or other dimensions in non-cylindrical pipes or tubes) and return to their original configuration when removed.

To accommodate this, the holding members may extend to an outer dimension of the lid (projected) or in some cases even beyond with the ability to contract sufficiently such that they can be fit within pipes with a number of different inner diameters or inner dimensions. Example sizes of pipes or cylinders are pipes having inner diameters of 63mm, 75mm, 90mm, 110mm, 125mm, 160 mm, 200mm, 250mm, 315mm and/or 400mm. Outer pipe diameters vary across markets and are typically standardized within a market or region, the inner diameters may also vary such that in different markets the same outer pipe diameters may have different inner pipe diameters. Accordingly the pipe cap according to the invention may be used in multiple markets by being suitable for a variety of pipe inner diameters as the holding members can contract continuously and are not limited to discretely different inner diameters. The diameter of the cap may be chosen during manufacture according to the desired market or usage.

The term “contractable” as used herein refers to the holding members being capable of bending or flexing inwardly or outwardly with respect to the centre point of the stem. This can be, for example, by elastic deformation or biased retraction, and holding members can be formed to have more or less ability to contract based on the shape, size, materials used, etc.

According to an embodiment, the cap comprises at least three holding members. Optionally this could be 3-12 holding members. Such a number of holding members can ensure there are sufficient holding members spaced around the stem to securely hold the cap in place, but not so much that it would be too difficult to contract the members and therefore to insert or remove the cap.

According to an embodiment, the plurality of holding members are tapered at the distal end of the stem from the lid. This can allow for easier insertion of the stem and resilient holding members of the cap, particularly when the holding members are biased to fit within a pipe with dimensions quite a bit smaller than the dimensions of the cap in an unbiased state. For example, when the holding members must be biased to a dimension at least 20% less than the dimension of the members in the unbiased state.

According to an embodiment, the holding members can be deformable blades, wings or flaps. Optionally, the blades could be rectangular and/or arcuate in shape and similar in structure to propeller blades. Further optionally, the blades are arranged in a spiral, extending radially from the stem at a substantially normal angle with ends curving in the same circumferential direction. Such blades could form simple biasing members for securing the cap to an end of a pipe, tube or other hollow member. The rectangular and/or arcuate shape can help to provide for simple manufacture and blade design, as well as a blade shape that can easily handle deformation and return to its unbiased position. The spiral arrangement can allow for easier biasing of the blades, particularly handy during insertion and/or removal. The holding members may alternatively be bent or angled linear sections, which may be especially useful in pipes with very small inner diameters.

According to an embodiment, the holding members may be outwardly biased overlapping plates. Such plates could be, for example, operating in the manner of a camera diaphragm shutter. For example, the plates might be biased outwardly by a spring and contractable to the compaction limit defined by the dimensions of the plates and degree of overlap achievable.

According to an embodiment, the stem is cylindrical. Optionally, the stem has a diameter in the range of 20-40% of the diameter of the unbiased holding members. Further optionally, the stem extends at a length of about 60-100% of the diameter of the unbiased holding members, perpendicularly from a first side of the lid. For example, a cap with holding members suitable for insertion into pipes with inner diameters of 110mm, 90mm and 75mm may have a stem length of 66-110mm. This can be a useful size ratio for ease of manufacture, and allowing the holding members to have sufficient length for ease of biasing, and to ensure there are sufficient contacts for proper holding forces when the cap is in use.

According to an embodiment, the holding member may be tapered, e.g., have a tapered and/or substantially conical tip section. This can be the individual holding members themselves and/or the end of the holding members and stem distal from the lid. Such a design can allow for ease of manufacturing in a mould and/or for facilitating easier insertion into a cylindrical opening. The cap may be twisted into a cylindrical opening by twisting in a direction against the direction of curvature of the blades.

According to an embodiment, the cap comprises polypropylene and/or polyethylene. Such materials can provide a durable cap with holding members which are able to be relatively easily biased without breaking. Alternatively, the cap may comprise any material with a degree of flexibility suitable to achieve the biased contraction of the holding members.

According to an embodiment, the holding members comprise a surface including rubber and/or another friction-providing material. This can help to ensure that the holding members and therefore the cap stay in position once inserted.

According to an embodiment, the lid is substantially planar. Such a substantially planar lid can be easily manufactured, use fewer materials, while providing the desired barrier at the end of the pipe. Optionally, the lid is circular. Alternatively, the lid could be non-planar, for example, having a handle, loop or other gripping or securing feature. The lid may feature a ventilation hole to allow fluid and/or thermal communication between the interior and exterior of the pipe during use of the cap.

According to an embodiment, the blades may be contracted or squeezed by hand until they form a sufficiently small cylinder to be inserted into a desired pipe. By 5 releasing the blades once inserted, the blades will internally press again the interior walls of the tube opening and hold the cap in place.

When the cap is produced for use with a range of relatively larger pipe inner dimensions or pipe inner diameters, it may be that a higher number of blades are more appropriate. For example a cap for use in cylinder inner diameters of 125mm, 160mm and 200mm may comprise at least four holding members. Another example is that a cap for use in cylinder inner diameters of 250mm, 315mm, and 400mm may comprise at least five holding members.

According to a further aspect, a pipe includes a cap with a lid on an outside end held in place by a stem extending from a first side of the lid and a plurality of resilient holding members extending radially from the stem to bias against an inner circumference of the pipe.

According to a further aspect of the invention, a method of making a cap for an opening is also disclosed. Such a method includes forming a lid section; and forming a stem section comprising a plurality of resilient holding members. The cross sectional area of the stem section is less than 70% of the lid area, and the plurality of resilient holding members extend from the stem section radially to at least the perimeter of the lid section.

Optionally, the method includes connecting the lid section to the stem, for example, with heat treatment, adhesive, welding or other means. Forming separately can make for easier manufacturing of each part, allowing for forming a lid section which is very close in size to the outer diameter or dimensions of the pipe or tube. Alternatively, the lid section and stem could be integrally manufactured for a stronger connection.

According to embodiments, the lid section and the stem section are formed by additive manufacturing and/or moulding. For example, a two-step moulding process could be used, moulding the stem section and holding members in a first mould and the lid section in a second mould. This would allow for easy moulding of different size lids for the same sized stem and holding members, allowing the holding members suitable for a given range of inner diameters or dimensions to be attached to a lid substantially equal to the outer dimension of the intended pipe. Inner and outer dimensions of pipes vary in different regions, with corresponding varied pipe wall thicknesses. Therefore it advantageous to be able to produce caps by alternately combining lid sizes to different sized holding members.

According to an embodiment, the method may involve a single type of plastic or a blend of plastics. The tips of the holding members may be provided with a rubber coating, or a coating comprising rubber or another material with a similar friction coefficient, which could also be added in a moulding process.

BRIEF DESCRIPTION OF THE DRAWINGS Exemplary detailed embodiments will now be described with reference to the accompanying drawings. Figure 1A shows a perspective view of a cap from a first side; Figure 1B shows an end view of the cap of Fig. 1A from a second side; Figure 1C shows a side view of the cap of Fig. 1A; Figure 2 shows an end view of a second embodiment of a cap; Figure 3 shows a cap according to an embodiment of the invention alongside a variety of pipes with which it may be sued. Figure 4 shows a cap according to an embodiment of the invention in use in pipes of various sizes. Figure 5 shows a cap according to another embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS A cap 1 according to an embodiment of the invention is shown in figures 1A- 1C. Fig. 1A shows a perspective view of cap 1 from a first side, Fig. 1B shows an end view of cap 1 from a second side, and Fig. 1C shows a side view of cap 1. The cap 1 includes lid 3, stem 2, and resilient holding members 4, which in this embodiment are formed as arcuate blades 4. The lid 3 is connected to the stem 2 at one end of the elongated stem which extends perpendicularly from a center of one side of the lid 3. Lid 3 and stem 2 {with holding members 4) can be formed integrally or separately and joined together. For example, stem 2 with holding members 4 could be formed in a first stage moulding process, with lid 3 formed in a second stage.

Arcuate blades 4 extend radially from the stem 2 as curved planes that are joined to the stem 2 along one edge. The arcuate blades 4 extend radially in a spiral formation. In this embodiment, cap 1 includes eight blades 4. The blades 4 extend spirally but do not overlap in an unbiased state. However, other embodiments could include more or fewer blades, and could be more or less spiraled. The radius of curvature of the arcuate blades 4 may be about 50%, 75%, 85%, 100%, 110% or 120% of the radius of the lid 3, optionally in the range 25mm to 600mm, for example any one of 30mm, 40mm, 45mm, 55mm, 75mm, 80 mm, 100mm, 125mm, 150mm or 200mm. While blades 4 are arcuate, in other embodiments, the holding members may be differently shaped, for example, comprising an angled linear plane, such as a ‘V'shape.

The blades 4 may be formed of a curved plane of resiliently deformable material. The blades 4 may have a radial extension and a length, and may be formed from plastic, for example polyethylene or polypropylene. One or more of the blades may have a rubber coating 6. The coating may be for example, on the convex curved side, optionally limited to the outer part thereof. This can help to increase the friction holding force within a pipe. The blades 4 may have a tapered end 5 (see Fig. 1C and Fig. 5) at the distal end from the lid 3. This facilitates easier insertion of the cap 1 into a pipe, and also can contribute to the ease of removing a cap 1 from a manufacturing mould.

Figure 1B shows the cap 1 from the lid 3 end. Lid 3 is shown as a planar circle in this embodiment, though could be differently shaped in other embodiments, for example, having a handle or other gripping part. The lid 3 may be made of a soft material such as a soft plastic such that it may be easily trimmed by cutting means, e.g., scissors. The material of the lid and/or holding members may be one or more of low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), polylactide (PLA), acrylonitrile butadiene styrene (ABS) or polycarbonate (PC).

In use, the lid 3 will cover or seal an opening, extending to the outer diameter or dimension of the pipe into which cap 1 is inserted. The lid 3 may have a diameter or maximum dimension anywhere in the range of 40mm to 630mm, optionally the lid 3 diameter or maximum dimension may be taken from the list 40, 50, 63mm, 75mm, 90mm, 110mm, 125mm, 160 mm, 200mm, 250mm, 315mm, 400mm, 500mm or 630mm.

The stem 2 has an outer dimension or cross-sectional area that is less than 70% of the area of the lid 3, with the holding members 4 being contractable to an outer dimension or diameter less than that of the lid 3. For example, blades 4 could contract to a diameter of less than 80% of the diameter of the lid 3; with the smallest contraction diameter being limited by the overlap compaction point of the holding members and the size of stem 2. In the illustrated embodiment of Figs. 1A-1C, the stem 2 cross-sectional area is approximately 10%-20% of the area of the lid, though could be anywhere in the range of 5%-80%. Therein the diameter of the stem can be 15-25% of the diameter of the lid 3, though could vary depending on requirements for the individual cap.

The stem 2 extends away from a side of the lid 3, and may be cylindrical or any other shape. In the embodiment of Figs. 1A-1C, stem 2 is a hollow cylinder, though could be solid in other embodiments. The diameter or outer dimension of the stem 2 may be in the range 10mm to 30mm. The stem may have a length of 50%, 60%, 70%, 80% 90%, 100% or 110% of the diameter of the unbiased holding members. These ratios provide efficiency of materials usage and manufacturing, however it should be understood that stem may be any length without deviating from functionality. For example the stem length may be 20mm to 100mm, and may vary depending on the size of the pipe and/or cap and required holding force for cap 1.

The lid 3 is separated from the proximal end of the blades 4 by a distance D (see Fig. 1C). The distance D may be in the range 5mm to 25mm, for example 5mm, 10mm or 20mm. The holding members 4 are spaced to be separated from the lid 3 to allow the contracting action of the holding members 4 to be uninhibited by contact with the lid 3, though the spacing can be quite minimal.

In use, the blades 4 deform and contract to fit within a pipe with an inner dimension which is smaller than the outer dimension of the blades 4 in a relaxed or unbiased state. The contraction can be induced manually, and cap 1 can be inserted into an end of a pipe such that stem 2 and blades 4 are within the pipe, and lid 3 remains outside the pipe on an end. Insertion can be through contracting blades 4, and then moving cap 1 into a pipe until at least the tapered end fits inside the pipe. Then the cap 1 can be rotated and pushed to insert fully such that only lid 3 remains outside the pipe.

Once inside, the blades 4 move back toward their relaxed state, but are limited by the inner dimensions of the pipe. In this way, blades 4 exert a radially outward force on the inside of the pipe, as shown in Fig. 4. This force secures the cap 1 to the end of the pipe, ensuring that lid 3 stays in place to keep dirt or other materials from entering the pipe. To remove, the cap 1 can be rotated and pulled out of the pipe.

As the diameter of the stem 2 is smaller than the lid 3 by a sufficiently large ratio, the blades 4 have space to deform and contract to fit within multiple opening sizes of pipes. As discussed in the background, prior art caps were formed substantially rigid, allowing for use with only a single size of pipe.

Cap 1, with a stem 2 with an outer dimension sufficiently smaller than the lid, and resilient holding members 4 extending outward from the stem allow for a single cap to fit multiple sized pipes. The ability of the holding members 4 to flex or contract to fit within and also bias outward toward the inner surface of multiple sizes of pipes ensures a secure hold for cap 1 in a number of different pipes. This saves on manufacturing costs and complexity, for example, substantially reducing the number of moulds needed for a range of pipes when the caps are produced by moulding.

Figure 2 shows a second embodiment of a cap 1’ from an end view. Cap 1’ includes similar parts and works similarly to cap 1 shown in Figs. 1A-1C, and only differences will be discussed. In the embodiment shown in Fig. 2, tips 6 of the blades 4 extend beyond the circumference of the lid 3. The holding members or blades 4 may extend beyond the lid 3 by any amount in the range of 5% to 50% of the diameter of maximum dimension of the lid 3. This allows for blades 4 to exert larger biasing forces for securing the cap, even on the larger sizes of pipes in which it can fit.

Caps may be formed in many different ways, for example, forming the cap in a mould or by additive manufacturing. The cap may be formed thereby in a single piece or as a separate stem section (with holding members) and lid section that are then connected by welding, glue or other attachment means. Some machining and/or trimming could be done on the cap, particularly to size lid 3 and/or to add a taper to an end distal from lid 3. Caps according to the invention can be formed in a variety of sizes according to the desired range of pipes, cylinders or other openings to be sealed. The tapered end of the blades may contribute to the ease of inserting or removing from a pipe and removing a formed stem section from a mould. Such an additive manufacturing and/or moulding process could be performed in any suitable workshop, making high volume production simple to achieve.

Figure 3 shows an example of a single cap 1 suitable for the cylinders W, X, Y and Z of inner diameters 110mm, 90mm, 75mm and 63mm, respectively. As shown in Figure 4, when a cap 1 is inserted in a cylinder, the blades deform or contract inwards toward stem 2, and are biased outwards to hold the cap 1 in place within the respective cylinder.

Due to the relative size of stem 2 with respect to lid 3, and the extension of contractable holding member 4, Cylinders W, X, Y and Z can all be covered or sealed with cap 1. This is shown in Fig. 4, with the largest pipe W showing the least contraction, and the smallest pipe Z showing blades 4 having the most contraction, but still fitting within the pipe such that the lid 3 can cover the end.

Figure 5 shows an embodiment of the invention wherein the holding members 4 have a coated portion 6 on the end edges. The coating 6 is of a higher friction material than the body of the cap, for example rubber. The coating provides more friction against the interior of a pipe when the cap is in use. This provides improved resistive force to the cap 1 being removed or accidentally falling from a tube. In some embodiments all of the outer radial ends of the holding members 4 can have the coating 6, and in other embodiments only some have the coating.

Figure 5 also shows another angle of tapering 5. The tapering at the ends may extend over either a minority or a majority of the length of the holding members.

Alternatively or additionally, the biasing and effect of suitability for multiple cylinder sizes could be achieved through other means.

By stating that the resilient holding members extend radially to at least the perimeter of the lid, at least some of the resilient holding members must extend radially outward from the stem such that a part of the holding member would extend as far as the lid extends radially.

In other words, if the lid were projected along the axis of the stem, at least a part of some holding members would extend to the outer perimeter.

Furthermore, terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features.

Descriptive terms should also be given the broadest possible interpretation; e.g. the term “comprising” as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification that includes the term "comprising", features other than that or those prefaced by the term may also be present.

Related terms such as "comprise" and "comprises" are to be interpreted in the same manner.

The present description refers to embodiments with particular combinations of features, however, it is envisaged that further combinations and cross-combinations of compatible features between embodiments will be possible.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention.

In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof.

Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (23)

Conclusions A cap comprising a lid, a stem extending from the lid, and a plurality of resilient retaining members extending radially from the stem to at least the periphery of the lid, the cross section of the stem portion being less than 70% of the lid surface. The cap according to claim 1, wherein the cap comprises at least three retaining elements. The cap of any preceding claim, wherein the plurality of retaining elements are tapered at the distal end of the stem. The cap according to any of the preceding claims, wherein the plurality of retaining elements comprises a plurality of deformable blades. The cap of claim 4, wherein each of the blades has a substantially rectangular shape. The cap of claim 4 or claim 5 wherein each of the blades is arcuate. The cap according to any one of claims 4 to 6, wherein the plurality of blades are arranged in a spiral. The cap according to any one of claims 4 to 7, wherein the plurality of blades comprises 3-12 blades. The cap according to any of the preceding claims, wherein the stem is cylindrical. The cap according to claim 9, wherein the stem has a diameter in the range of 10-30 mm. The cap according to any of the preceding claims, wherein the stem extends about 60-100% of the diameter of the unstressed retaining elements perpendicularly from a first side of the lid. The cap according to any of the preceding claims, wherein the cap comprises polypropylene and/or polyethylene. 40 The cap according to any of the preceding claims, wherein the plurality of retaining elements comprise a rubberized surface. The cap according to any of the preceding claims, wherein the lid is substantially planar. The cap according to any one of the preceding claims, wherein the lid is round. The cap of any one of claims 1 to 3 wherein the plurality of retaining members comprise overlapping panels biased outwardly. A tube with a cap according to any one of the preceding claims. 18. A method of manufacturing a cap for cylindrical openings, the method comprising the steps of: forming a lid portion; and forming a stem portion comprising a plurality of resilient retaining members extending radially from the stem portion; wherein the cross section of the trunk portion is less than 70% of the lid area. The method of claim 18, further comprising connecting the lid portion to the stem portion. The method of claim 18, wherein at least one of the lid portion and the stem portion is formed by additive manufacturing. The method of claim 18, wherein at least one of the lid portion and stem portion is formed by molding. The method of any one of claims 18 to 21, wherein the lid portion and the stem portion are joined by one or more of: heat treatment, glue, and welding. The method of any one of claims 18 to 21, wherein the lid portion and the stem portion are integrally formed.