US20060243733A1

US20060243733A1 - Molded paint can with knit-free handle

Info

Publication number: US20060243733A1
Application number: US11/118,139
Authority: US
Inventors: Terry Kline; Michael Tunison
Original assignee: Central Can Co Inc
Current assignee: Central Can Co Inc
Priority date: 2005-04-29
Filing date: 2005-04-29
Publication date: 2006-11-02

Abstract

A paint can has a molded plastic bucket and cover which are releasably engageable with one another at a seal. The bucket has an integrally-formed, knit-free handle. The anchors for the handle are knit to the side wall or reinforcing ring of the bucket.

Description

BACKGROUND OF THE INVENTION

This invention relates to containers for liquids and is particularly concerned with a container intended for use with paint and similar materials. It will be understood that the invention is directed to the structure of a container, and is not limited to use with any particular contents. Obviously the purpose of a paint can is to contain paint in a condition that prevents unintended release or removal of the liquid from the bucket, while allowing convenient access to the liquid when desired. A paint can requires a rugged, reliable, sealing engagement between the top of the bucket and the cover. Simultaneously, access to the can's contents requires the cover to release its engagement with the bucket upon reasonable, directed effort on the part of the user. These somewhat contradictory requirements have more or less been resolved in satisfactory fashion over the years for traditional metal paint cans. Recently, however, for reasons of cost and convenience, paint cans integrally molded from plastic materials have become competitive with the metal paint can.
Paint cans have traditionally been provided with a carrying handle and plastic paint cans are no exception. Metal cans usually had a handle in the form of a wire bail. The bail was a separate piece that was pivotally attached to the bucket. The ends of the bail were received in receptacles attached to the bucket to form a hinge. It is preferable in plastic cans not to have the handle formed as a separate part, due to the extra manufacturing step of attaching such a handle to the bucket and due to the problems of assuring that a separate handle remains connected to the bucket. Thus, the handle is integrally formed in plastic paint cans. However, this has also proven to have its share of problems in prior molded paint cans. Such buckets have a generally semi-circular handle fastened to opposite sides of the bucket near the top edge of the bucket at attachment anchors. Living hinges are formed at the junctions of the handle and anchors. The molding process used in prior art cans formed the handle by feeding molten plastic material into a mold cavity from the bucket floor, into the walls, through the two attachment anchors and into the handle cavity from both ends. The plastic material feeding into the handle cavity from the two anchor areas would meet some-where in the arcuate extent of the handle cavity, typically somewhere near the middle. These two separate bodies of plastic material feeding into the handle cavity would then have to blend together or knit to form the complete handle. While this can be accomplished under carefully controlled molding conditions and with properly selected grades of materials, doing so can increase the cost of the paint can due to the need for more expensive molding equipment, slower cycle times and increased material costs. More importantly, it has been found that molding the handle by attempting to knit two bodies of plastic fed from separate directions can lead to handle failures when optimum conditions and materials are not utilized. When such handle failures occur, particularly with an open bucket at a work site, the results are not favorable for either the painter or the paint supplier. Particular unpleasantries are reserved for the paint can manufacturer when the knit handle fails. The present invention resolves these issues by providing an improved molded paint can.

SUMMARY OF THE INVENTION

The present invention concerns a paint can that can be molded of plastic material. A primary object of the invention is a paint can having a knit-free handle attached to the bucket by knitting the handle anchors to the walls of the bucket.
The paint can has a bucket and cover which are releasably engageable with one another. The cover has sealing elements that cooperate with the upper edge of the bucket. Inner and outer sealing walls on the cover receive the top land of the bucket. The bucket is molded by feeding molten plastic material into a mold cavity both from two separate gates in the mold. The two gates feed into mold cavities for the floor of the bucket and from the center of the handle. The fed materials meet somewhere in the side walls of the bucket so the two streams knit together at a point remote from the handle itself. This forms a knit free handle and places the knit locations at a point where the loads on the container will be spread out over the greatest area.
These and other desired benefits of the invention, including combinations of features thereof, will become apparent from the following description. It will be understood, however, that a device could still appropriate the claimed invention without accomplishing each and every one of these desired benefits, including those gleaned from the following description. The appended claims, not these desired benefits, define the subject matter of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of the bucket of the present invention.
FIG. 2 is a top plan view of the bucket of FIG. 1.
FIG. 3 is a bottom plan view of the bucket.
FIG. 4 is a section taken along line 4-4 of FIG. 2.
FIG. 5 is an enlargement of the upper left corner of FIG. 4, illustrating the details of the top edge of the bucket.

DETAILED DESCRIPTION OF THE INVENTION

The paint can of the present invention includes a bucket and a cover or lid. The bucket 10 will be described in conjunction with FIGS. 1-5. The bucket 10 includes a circular floor 12. The center of the floor panel may have a dimple or indentation 14. The dimple provides an advantageous location for one of the gates in a mold that feeds plastic material for forming the bucket. The molding process is an important feature of the present invention and will be discussed in greater detail below. On the underside of the floor 12 there is a circular foot 16. The foot is engageable with a cover of a second paint can to facilitate stacking of multiple cans.
The bucket further includes a cylindrical wall 18 that extends upwardly from the outer edge of the floor 12 to an upper, open end. The wall joins the floor at a junction 19. The wall 18 has an inner face 20 and an outer face 22. At the upper end on the inner face there is a very slight indentation formed by a mold parting line 24 (FIGS. 4 and 5). The upper end portion of the wall terminates at a top land 26. The top land joins the inner and outer faces 20, 22 at corners 28 and 30 (FIG. 5). The corners have a simple radius. Corner 28 defines a circular opening into the interior of the bucket. At the upper end of the wall 18, on the outer face 22, there is a radially extending projection 32. This projection encircles the top of the bucket. It meshes with a catch on the cover to retain the cover on the bucket. The upper end of the wall 18 also includes a reinforcing ring 34 just beneath the projection 32 on the outer surface 22 of the wall 18. The ring is formed by a radial extension 36 and an axial flange 38 attached to the extension. Arcuate ribs or gussets 40 (FIG. 3) are formed underneath the radial extension and inside the axial flange to further stiffen the ring 34.
A pair of handle anchors 42, 44 are attached to the upper end of the bucket wall. In a preferred embodiment the anchors are formed on the outer edge of the reinforcing ring 34, as seen in FIGS. 2 and 3. Alternately, the anchors could be attached directly to the outer surface 22 of the upper end of the wall. The anchors mount a handle 46. It will be understood that the handle is shown in the as-molded condition where it is in a generally horizontal plane. In use the handle will be pivoted about the anchors to a substantially vertical plane with most of the bucket hanging below the handle. FIG. 2 shows that the handle is a generally semi-circular bail which includes two outer portions 48 and a central portion 50. FIG. 1 shows that central portion 50 has a lower edge 54 that widens the handle in the central portion. Finger indentations or grooves 52 are provided on the underside of the central portion. The central portion provides a cushioned grip that reduces the tendency of the handle to dig into a user's hand or fingers when carrying a full paint can. The finger grooves 52 further enhance the comfort of the handle.
The construction of the handle and in particular the central portion 50 is noteworthy. As best seen in FIG. 1 the central and outer portions 48, 50 have coplanar upper surfaces. However, the lower surface 54 of the central portion extends downwardly below the lower surfaces of the outer portions 48. It will be understood that the references to “upper” and “lower” surfaces of the handle are with respect to the horizontal, as molded condition of the handle, as shown in FIG. 1, before the handle is pivoted to a vertical plane for use. Two frangible tabs 55 connect the handle outer portions 48 to the reinforcing ring 34. The tabs are small enough to be readily broken when the handle is lifted to a vertical position for use. With the construction shown the cross sectional area of the central portion 50 is greater than that of the outer portions 48. The handle 46 is formed in a manner that leaves it free of molding knit zones, as will be described below.
A suitable cover (not shown) will be provided to close the open end of the bucket. The cover forms no part of the present invention.
A variety of plastic materials may be suitable for the bucket. A preferred material for the bucket is a polypropylene copolymer. However, it will be understood that substitutions for this material could be made without departing from the scope of the present invention.
The process for molding the bucket is as follows. A mold is prepared that has cavities for forming the floor, the wall including its upper end portion, the handle anchors and the handle. The cavities are in fluid communication with one another so the entire bucket is molded at the same time. Specifically, the handle cavity communicates with the anchor cavities which in turn communicate with the cavity for the upper end portion of the wall, including the reinforcing ring. The wall cavity communicates with the floor cavity. For these purposes the foot may be considered part of the floor. The mold cavities are filled from two gates, one located at the floor dimple 14 and one formed at or near the central portion of the handle. Molten plastic material is fed from both of these gates. The feeding process is controlled so that while the majority of the material is fed through the floor gate, all of the material forming the handle and handle anchors is fed through the handle gate. Thus, the handle material enters the handle gate and flows in two directions from the gate through the handle cavity, into the handle anchor cavities and tabs and from there into the reinforcing ring portion of the wall cavity. Floor fed material joins or knits with the handle fed material in the wall cavity, in the vicinity of the handle anchors but spaced from the handle anchors. Accordingly, no knitting of material occurs in the handle cavity. The handle is free of knitted areas or zones. There are knit zones in the walls. However, the knitting that occurs in the walls is in areas of lesser stress concentration than the handle and thus there is a reduced chance of failure than if there were a knit zone in the handle. This molding process greatly reduces the chances of handle failures while also reducing cycle times by decreasing the amount of time it takes to fill the mold.
While the preferred form of the invention has been shown and described herein, it should be realized that there may be many modifications, substitutions and alterations thereto. For example, while the anchors are shown attached to the reinforcing ring, they could be attached directly to the wall of the bucket. That is, the reinforcing ring may be located spaced from the anchors. Or in certain circumstances it may be possible to delete the reinforcing ring altogether. Thus, the knitting of molten plastic material may take place in the reinforcing ring, if there is one, or it may take place in the bucket wall, whether the reinforcing ring is present or not. What is important is that the knitting does not take place in the handle cavity. Also, while the bucket wall is shown as completely cylindrical, it need not have this exact shape. It could have a conical portion or it could include hand grips formed in the sides.

Claims

1. A molded bucket, comprising a floor, a wall attached to the floor and extending therefrom to an upper end, a pair of handle anchors connected to the upper end of the bucket wall, and a knit free handle extending from the handle anchors, the handle anchors being connected to the upper end of the wall at knit zones which are remote from the handle.

2. The molded bucket of claim 1 wherein the upper end of the wall further comprises a reinforcing ring extending at least partially around the wall with the handle anchors being attached to the reinforcing ring.

3. A bucket having a floor, a wall having an upper end, and an arcuate handle attached at two anchors to the upper end of the wall, the bucket being formed by the process of:

forming handle, anchor, floor and wall cavities in a mold with the handle and wall cavities being in fluid communication with the anchor cavities and the floor and wall cavities being in fluid communication with one another;

feeding molten material into the mold cavity for the handle;

feeding molten material into one of the mold cavities for the floor and wall;

controlling the feeding of molten material such that the anchor cavities are filled from the handle cavity;

solidifying the molten material in the mold cavities; and

releasing the finished bucket from the mold cavities.

4. A method of making a bucket having a floor, a wall having an upper end, and an arcuate handle attached at two anchors to the wall, the method comprising the steps of:

feeding molten material into the mold cavity for the handle;

feeding molten material into one of the mold cavities for the floor and wall;

solidifying the molten material in the mold cavities; and

releasing the finished bucket from the mold cavities.

5. The method of claim 4 wherein the controlling step is further characterized by feeding the molten material such that material fed into the handle cavity extends at least partially from the anchor cavities into the wall cavity.

6. The method of claim 4 wherein the forming step is further characterized by forming the wall cavity to include a reinforcing ring cavity near the upper end.