FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
The present invention relates to container lids, and more particularly to a metal slide lid.
A typical container which uses this type of lid is a low profile container having a formed upper edge which fits into formed tracks in the lid. The lid can thereby be slid back from the closed position, without removing it from the container, to allow dispensing of the container contents. Containers of this sort can be used with pills, candies, and breath strips for example. The lid can also be used with taller containers having the same type of top opening for example, for dispensing bandage strips.
The prior art has produced close fitting slide lids, but at the expense of exposed raw metal edges and sharp corners often capable of cutting the fingers, or of cutting or snagging the pocket or purse liner.
- BRIEF SUMMARY OF THE INVENTION
For example, FIG. 1 shows a typical prior art container 20 with slide lid 21. The container 20 has a rolled lip 22 positioned to be engaged by the slide portions of the lid 21. The lid 21 has inwardly bent edges 24 to form, with the planar cover, a pair of fairly closely fitting channels 23. The fit of the channels 23 over the lip 22 is such that the lid can be readily manipulated by hand to be slid back to open the container or forward to close it. The channels 23 are formed by downwardly turned peripheral edges 24, which leave a raw edge 23 a. Similarly the forward edge 25 of the container lid is positioned to engage the fingers if the fingers are placed into the container when the lid is open. The raw edge 23 a of the channels 23 also exposes a sharp corner 23 b which is also capable of snagging or cutting. The back end of the lid (see FIG. 2) also has raw metal edges 27 which are also capable of cutting or snagging. However, the benefits of such a lid, including the closely fitting nature of the lid to the container, are sufficiently attractive that it is sometimes desirable to use lids of this sort in spite of the exposed raw metal edges.
In view of the foregoing, it is a general aim of the present invention to provide an improved slide lid for a container, sometimes called a safety lid, in which the disadvantages of the raw metal edge are reduced or substantially eliminated.
In that regard, an object of the present invention is to provide a metal slide lid for a container which minimizes the presentation of raw edges to the user of the container, while still providing a close tight fitting slide lid which closely mates its associated container.
In accordance with the method aspects of the invention, an object is to provide a simplified process for forming a safety lid as described above.
The invention provides a metal slide lid for a container in which a pair of rolled rails depend from a substantially planar top portion at two sides of the top portion, and have finished edges. The rolled rails are shaped and positioned to allow the cover to slide over a corresponding lip of a container bottom. A forward edge of the top portion is formed with a peripheral hem which extends between the forward edges of the rails. As a result, substantially all of the raw edges of the metal blank are shielded.
The invention also has method aspects which include the steps of forming from sheet metal, from operations including a punch and draw operation, a metal blank having a planar lid portion and a drawn edge sections depending from the periphery thereof. A first portion of the drawn edge sections is of a first height, and a second portion is of a lesser height. The drawn blank is then engaged with a punch which inwardly curls both drawn edge sections. The curled first portion is then engaged with a tool adapted to roll the first drawn portion into a roll spaced from the underside of the lid by an upstanding section. The upstanding section is of sufficient height to cause the rolled portion to engage an edge of a container for sliding the cover onto and off the container. The tool also engages the curled second portion to form a hem tightly engaging the underside of the planar surface to provide a protective edge to the forward portion of the lid.
In the preferred practice of the method the step of forming and drawing a metal blank includes performing a flat piercing operation around a portion of the periphery and then a blank and draw operation.
BRIEF DESCRIPTION OF THE DRAWINGS
Finally, the invention provides a slide lid for a container in which a metal blank has a substantially planar central portion and a formed periphery. Part of the periphery is formed into a roll spaced from the underside of the planar portion by a sufficient distance to allow the lid to slide on a lip of a corresponding container. Substantially all of the remainder of the periphery is formed into a tight hem. As a result all of the raw edges of the blank are shielded by formed shapes.
These and other objects will become apparent from the following detailed description when taken in conjunction with the drawings in which:
FIG. 1 is a perspective view of a prior art container with slide lid;
FIG. 2 is a partial rear perspective view of the container of FIG. 1;
FIG. 3 is a perspective view of a container having a lid constructed in accordance with the present invention;
FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3 showing the lid interfitting with the container;
FIG. 5 is a sectional view taken along the line 5-5 of FIG. 3 showing the tightly formed hem;
FIGS. 6-9 illustrate the steps of the preferred method of forming a lid according ot the invention;
FIGS. 10 and 11 are perspective views of an additional embodiment of the invention.
- DETAILED DESCRIPTION OF THE INVENTION
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Turning now to the drawings, FIG. 3 shows a safety slide lid 31 in partly opened position on a container 30. Both the container and the lid are rectangular in the illustrated embodiment, although other shapes are possible, so long as two parallel sides for operation of the slide lid are provided. The container 30 has a bottom 32 and upstanding sides 33, as is conventional. The upstanding sides 33 terminate in a formed upper feature, shown herein as a rolled lip 34. The rolled lip 34 projects outwardly from the sides 33 (see FIG. 4) so as to provide means for interfitting into the slide lid. Preferably the sides 33 and the rolled lip 34 are continuous around the periphery of the container. However, as noted above, the main requirement for interfitting with the slide lid, is that a pair of opposed sides carry lips projecting at their upper edges for interfitting with a safety slide lid, to allow the lid to slide on and off the container.
The lid 31 has a planar top 41 formed much like the top 21 of FIG. 1. In contrast to FIG. 1, however, substantially all of the edges of the lid 31 are formed in such a way as to shield the raw material edges. Thus, in practicing the invention, the parallel sides which form the rails have depending sections 42 having elongate portions 44 of sufficient length to extend past the rolled lip 34 of the container (see FIG. 4). The depending sections 42 then are terminated in rolled portions 45 in which the raw material edge is rolled to a position very close to the inward side of the depending sections 42, to shield that raw material edge. The depth 44 of the depending sections 42, and the position of the roll 45 is selected such that a slip fit is achieved in the channel 46 formed between the top of the formed roll 45 and the underside of the top portion 41, which is adequate to slidingly receive the formed edge 34 of the container. In addition the edges 47 of the rolled portions 45 are not perpendicular to the top 41, but are angled toward the roll 45 so as to shield, to the extent possible, the edges 47. The construction, with the angled edge 47 tends to recess the roll of the roll portion 45 behind the edge of the depending portion 44.
In the illustrated embodiment, not only are both side portions formed as just described, but the back portion is as well, such that the back channel provides a stop member to define the closed position of the cover. A nib 46 is located in the top section to provide a detent for holding the cover in the closed position. Additional detents can be formed in the cover for defining the open position.
Also in contrast to the prior art, the front section of the slide lid is configured in such a way as to shield the raw material edge. To that end, the front edge 50, and portions of the side edge 51, 52, extending to the channel 46 are formed in a tight hem 53, in which the material is folded back on itself and crimped. In this way, the forward edge 55 presented by the slide lid will be a blunt double section of material where the material is folded back on itself. Preferably the hem is formed (see FIG. 8) such that it shields the base (where it joints the planar lid) of the rolled portion.
It will now be apparent that the slide lid as illustrated in FIG. 3 has far superior characteristics to the prior art illustrated in FIG. 1 in that the chances of cutting the fingers or snagging the clothing is substantially reduced.
The manufacturing techniques for forming the container are also greatly simplified and will be described in connection with FIGS. 6-9. Note that FIG. 6 is drawn to a slightly smaller scale then FIGS. 7-9.
The lid is stamped from thin (0.008 to 0.010 inch) sheet steel in an efficient process employing a minimum number of metal forming operations. In the preferred practice of the invention, we will refer to separate piercing, and punch and draw operations. However, for different shapes and using different equipment, the blank might be formed from only a single set of operations, and we will generically refer to that process as forming a blank from sheet metal by way of operations including a punch and draw operation. The first operation or set of operations operates on raw sheet metal 80 (usually already decorated), and forms a blank having a substantially planar lid portion and drawn edge sections depending from the periphery thereof. The final product of this set of steps is shown in FIG. 7. In the preferred practice this first set of operations is made up of two individual operations, primarily for convenience as a result of the shape being formed. In other cases, only a single punch and draw operation might be needed. However, using the shape shown in the drawings, the preferred practice first performs a flat pierce operation which forms the hem periphery. A piercing tool removes a small section of material to form an opening 81 which defines the hem edge 82, in preparation for forming the remainder of the blank outline (see phantom lines 83) with a subsequent, blanking operation. A second operation, blank and draw, is performed, in which a blank and draw tool set engages the raw sheet stock 80 to form the shape 60 illustrated in FIG. 7. As is well known, a blank and draw tool set will first cut a blank from the sheet stock, then form the blank by a drawing operation to produce a drawn shape established by the dimensions of the tool set. In the present instance the shape includes the cover having a planar top 41′, in which the prime numerals indicate similar portions to that illustrated in FIG. 3, with the difference being in the relative dimensions of the parts to form a cover of somewhat different shape and size. The draw operation also forms a U-shaped set of depending sides 61 which will form the side rails and back rail, and a smaller U-shaped depending section 62 which will form the hemmed edge. A dimple 63 is also formed in this second operation. Also of note are the angled portions 64 which, when the rolls are formed, will create the angle of the roll edge previously described.
The next operation, typically referred to as start curl and start hem, is then performed as shown in FIG. 8. The workpiece 60 is transferred either to a different station of the same press or to a separate press for performance of this operation. A punch engages the upstanding members 61 and 62. The punch has an angled surface which is intended to produce a start curl and start hem configuration in which the upper edges of the curl 65 and the upper edges of the hem 66 are bent slightly inwardly as illustrated in FIG. 8.
The workpiece is then transferred to a final station where a curl die and hemming die engage the workpiece. The curl die engages the curled edge 65 of the start curl portion and is so-shaped as to roll the edge downwardly into a continuous roll 68 as illustrated in FIG. 9. This is performed around the entire periphery of the U-shaped channel 61, at the upward internally turned edge 65 to form a continuous roll as shown in FIG. 9. The die also has a hem section which engages the upper curled portion 66 of the short upstanding member 62 to produce a thin flattened hem 69 as illustrated in FIG. 9. The cover is now completed, with the exception of any cleaning or filling operations. It will be seen from an examination of FIG. 9 that the curl is formed without any crude transitions, such that the sheet metal to which the users fingers are exposed is completely smooth. Similarly, the hem 69 is tight such that the raw edge 70 of the material is closely positioned with respect to the underside of the cover section 41′, and is not in a position to cut the finger or snag the clothing.
The cover produced by the practice of the invention thus resolves a number of the deficiencies in prior art slide covers. The method of production, requiring only four relatively simple punching steps, adds to the cost effectiveness of the inventive solution.
FIGS. 10 and 11 show an additional embodiment, currently believed to be preferred, of a safety lid according to the present invention. It is in all aspects important to the invention the same as the embodiment of FIG. 3, except for the relative proportions. Whereas FIG. 3 presents a lid which is longer and narrower, the FIGS. 10 and 11 embodiment is somewhat more boxlike. But like the FIG. 3 embodiment, the lid of FIGS. 10 and 11 has a substantially planar cover 41 rolled sections 45 angled backwardly at 47 and positioned to create a gap 44 of sufficient dimension between the top of the roll 45 and the bottom of the planar cover 41 to accept a rolled lip of an associated container. The forward edge 55 of the lid is doubled and hemmed as in the FIG. 3 embodiment. In minor contrast to FIG. 3 which has only a single dimple 46 for defining a closed position, the FIGS. 10 and 11 embodiment also has dimples 46 a for defining a container-open position.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.