US3469732A - Plastic closure - Google Patents

Description

Sept. 30, 1969 A, FOSTER 3,469,732

PLASTIC CLOSURE Filed April 1, 1968 2 Sheets-Sheet 1 {52.3 6 as 2135! S sz I 37 714- 4 i 4'2 dean I pt, 3, 1969 J. A. FOSTER 3,469,72

PLASTIC CLOSURE Filed April 1, 1968 2 Sheets-Sheet 2 Unite States Patent O 3,469,732 PLASTIC CLOSURE John A. Foster, Rockford, Ill., assignor, by mesne assign. ments, to J. L. Clark Manufacturing Co., Rockford, 11]., a corporation of Delaware Filed Apr. 1, 1968, Ser. No. 717,764 Int. Cl. B65d 43/16 US. Cl. 220-31 15 Claims ABSTRACT OF THE DISCLOSURE A single-piece molded plastic closure adapted to be mounted on a spice can and having a segmental spoon opening closed by a flap integrally hinged to one side of the opening, and a segmental sifter opening similarly closed by an integrally hinged flap. Depending from the underside of each flap is a rib that interfits with the side surfaces of the respective opening from one end of the hinge to the other, the rib on the sifter flap having sifter openings therein. Each flap is latched releasably in the closed position by interfitting abutments, and is sealed by a resiliently flexible fin of plastic molded on the side surface of the opening, completely around the rib, and inclined downwardly and inwardly for interfering engagement with the rib during closing motion of the flap. Finlike compressible extensions on the ends of the ribs abut against alined, opposed surfaces on the straight sides of the openings to form pressure seals from the hinges downwardly to levels below the fin seals, and clearances are formed between the edges of the ribs adjacent the hinges and the opposed edge surfaces of the openings and covered by wings on the flaps.

Background of the invention This invention relates to a single-piece molded plastic closure for a spice can, of the same type that is disclosed in my prior patent, No. 3,322,208,-in which the closure is formed with one or more openings normally closed by flaps integrally hinged on the closure for swinging between open and closed positions, two such openings being preferred so that the contents may be dispensed either with a spoon inserted into the can through one opening or by shaking the contents out of the can through a sifter on the flap of the other opening. In the aforesaid patent, the openings are sealed by ribs depending from the flaps and having outer surfaces pressed into tight sealing engagement with the edge surfaces defining the openings when the flaps are closed. It has been found, however, that this manner of sealing requires careful control of dimensions in molding and can result in problems after a set of molding dies has been in use for a substantial period of time.

Summary of the invention The primary object of the present invention is to improve the sealing characteristics of the patented closure by eliminating the need for precise control of dimensions of sealing elements during molding, thereby increasing the useful service life of dies, simplifying die maintenance and improving the sealing characteristics of the closure. Another object is to seal the openings in the closure with novel resilient sealing elements molded integrally with the remainder of the single-piece closure and operable to provide a complete peripheral seal around the rib on each closure that remains effective despite dimensional variations resulting from wear in the dies or inherent in molding techniques. A more detailed object is to provide a thin and laterally yieldable sealing fin positionad on the surfaces of the closure defining the opening for interfering,

sealing engagement with the rib from one end of the latter to the other, regardless of normal variations in the positions and dimensions of the fin and the rib, and to form novel pressure seals between the ends of the ribs and the adjacent side of the opening for completing the full peripheral seal. Another object is to leave substantial clearances between the rib and the side surfaces adjacent each hinge for facilitating die maintenance without danger of leakage, and to cover such clearances in a novel manner to avoid detracting from the appearance of the closure.

Other objects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

Brief description of the drawings FIGURE 1 is a top perspective view of a closure embodying the novel features of the present invention shown with the closure flaps in the fully open positions in which they are molded.

FIG. 2 is a cross-sectional view taken substantially along the line 22 of FIG. 1 in the direction indicated by the arrows.

FIG. 3 is an enlarged view similar to FIG. 2 with the flaps in the closed positions.

FIG. 4 is an enlarged fragmentary cross-sectional view taken substantially along the line 4-4 of FIG. 3, and illustrating the seals at the ends of the ribs.

FIG. 5 is an enlarged fragmentary cross-section taken substantially along the line 5-5 of FIG. 2.

FIG. 6 is an enlarged fragmentary cross-section taken substantially along the line 6-6 of FIG. 3.

FIG. 7 is an enlarged fragmentary cross-section taken substantially along the line 77 of FIG. 2.

FIG. 8 is an enlarged fragmentary plan view showing part of the top of the closure at one end of the hinge of the spoon-hole flap.

FIG. 9 is a fragmentary cross-section taken substantially along the line 99 of FIG. 8.

As shown in the drawings for purposes of illustration, the invention is embodied in a single-piece, molded plastic closure or cover for a conventional spice can (not shown) of generally rectangular cross-section, the closure having a flat top 10 defining at least one dispensing opening 11 (FIG. 1) normally closed by a hinged flap 12, and also having depending inner and outer skirts 13 and 14 defining a peripheral groove 15 for telescoping and interlocking with the hemmed upper end of the can to mount the closure on the can. Preferably, the opening 11 is a spoon hole that is shaped and sized to admit a spoon into the can, and a second opening 17 is formed in the top and normally closed by a hinged flap 18 with a sifter 19 on its underside formed With a series of holes 20 that are exposed when the flap is raised to its open position so that the contents of the can may be dispensed either by spooning through the spoon hole or by shaking small quantities of the contents out through the sifter holes.

While the openings 11 and 17 may have various shapes, each herein is defined along one side by a straight side surface 21, 22 and along the remaining sides by a substantially arcuate side surface 23, 24 whereby the openings are generally segmental in shape, the surfaces of both openings being upright and generally at right angles with the plane of the top 10. The straight side 21 of the spoon hole 11 lies along one elongated side of the top, herein referred to as the rear side, with the flap 12 integrally joined to the top along the rear side by an integral web 25 forming the hinge. The straight side 22 of the sifter opening 17 extends across the top adjacent one end of the spoon hole, and the flap 18 is integrally joined to the top along this straight side by a similar web 27 forming the other hinge.

In this instance, the flaps 12 and 18 are thin and flat plates having side edges 28, 29 generally perpendicular to the respective hinges, and converging outer edges 30, 31 that terminate in squared lift tabs 32, 33 projecting forwardly or outwardly from the flaps. As shown most clearly in FIG. 1, the top is recessed at 34 and 35 to receive both flaps with the upper sides thereof flush with the top, and has notches 37 (see FIG. 3) beneath the closed positions of the lift tabs for easy opening of the flaps.

Formed on the underside of the spoon-hole flap 12 is a depending rib 38 of the same shape as the side and front surfaces of the spoon hole 11 and extending forwardly from the hinged edge of the flap at one end of the hinge, curving across the front edge portion of the flap inwardly from the edges 30 and the tab 32, and then extending back to the hinge. Adjacent the hinge, both the rib and the hole-defining surfaces preferably have straight end sections 23*, 38 generally perpendicular to the hinge. Thus, as the flap is pressed from the open position (FIG. 2) into the closed position (FIG. 3) overlying the spoon hole, the rib is pressed into the hole in side-by-side relation with the surfaces of the top defining the hole. A rearwardly projecting retaining head 39 along the front of the hole interlocks releasably in a forwardly opening groove 40 in the rib immediately beneath the lift tab to latch and retain the flap in the closed position.

The sifter 19 (FIGS. 1 and 7) also is in the form of a rib integrally molded on the underside of the sifter flap 18. This rib is of special, part-spherical contour so as to fit closely inside the arcuate surface 24 of the sitter opening 17. The sifter holes 20 are arranged in a row spaced below the level of the underside of the flap to lie well within the opening When the flap is closed and to be exposed above the top 10 when the flap is in an open position at an angle on the order of forty-five degrees with the plane of the top. Outwardly extending lips 41 (FIG. 1) around the arcuate lower edge of the sifter abut against an opposed abutment on the top to limit upward swinging of the flap in this open position, and a groove 42 (FIG. 7) on the sifter above the sifter holes receives a bead 43 on the wall 24 to latch the flap releasably in the closed position.

As in the aforesaid patent, the closure is molded in one piece with the flaps 12 and 18 disposed in the positions shown in FIGS. 1 and 2 and joined to the top 10 only by the hinge webs 25 and 27. The plastic used is selected for proper resilient flexibility in the thinner sections, in the hinges and in the retaining elements for the flaps, and for removal of the closures from the molding dies. To prevent leakage of the contents of the cans during shipping and handling, it is very important that each of the openings 11 and 17 be sealed tightly when the flaps are closed, particularly in view of the fact that shipping containers often are turned upside down and subjected to vibration and other jostling. While the patented closure produces an adequate seal as originally designed, it has been found that wear in the molding dies after a substantial period of use can result in the production of closures with progressively weaker or looser seals, particularly near the hinge along each edge of each flap, with a resulting tendency to leak during handling. Accordingly, avoidance of leakage requires careful attention to and maintenance of dies to hold the sealing surfaces to close dimensional tolerances.

In accordance with the present invention, the seal between the primary flap 12 and the edge surfaces of the opening 11 is formed by a resiliently flexible fin 44 molded integrally onto the side surfaces 23, 23 of the opening from the rear side 21 thereof at one end of the hinge 25 completely around the opening to the other end of the hinge and positioned for tight sealing engagement with the rib 38 when the flap is closed. The fin is inclined downwardly and inwardly across the path of the rib during closing of the flap, for interfering engagement with the rib completely around the free portion of the fiap, regardless of dimensional variations that may occur in molding and even after prolonged periods of service use of the dies. As the flap is closed, the fin engages the rib and yields and is expanded outwardly by the rib, thereafter pressing resiliently against the full length of the rib for a highly elfective seal.

In addition, opposed, resiliently compressible sealing elements 45 and 47 formed on the rear side 21 of the opening and on the ends of the rib 38 are positioned for interfering, sealing engagement when the flap is closed, thereby to complete the seal completely around the periphery of the flap while maintaining the capability of high-speed production of the closure as a single-piece molding. While the invention is usable in connection With one opening alone, the sifter opening 17 preferably is sealed in a similar manner.

In this instance, the fin 44 comprises an elongated strip of the plastic material integrally joined along its upper edge to the edge surfaces 23, 23 of the spoon hole 11 at a level spaced below the top to leave an appreciable Width of the edge surfaces exposed above the tin. The lower edge portion of the fin is inclined downwardly and inwardly, when free, at an angle on the order of fifteen to thirty degrees with the exposed edge surfaces. Outside this free edge portion is a downwardly opening groove 48 that is defined between the fin and an outwardly offset skirt 49 depending from a thickened portion of the top on which the exposed edge surfaces are formed, and each end of the fin is integrally joined to the rear side 21 of the opening.

As shown most clearly in FIGS. 13, the rib 38 has an outer upright surface 50 that herein is inclined downwardly and inwardly from its upper margin at the underside of the flap 12 at an angle less than the incline of the fin, for example, five degrees, so as to enter the spoon hole 11 freely and thereafter to wedge tightly into the fin 44 as the flap is closed. This wedging, interference fit deforms and expands the fin laterally and outwardly, as permitted by the space in the groove 48 outside the fin, and leaves the latter stressed and pressing tightly against the rib along a sealing line extending all the way around the lib, from one end to the other. Because the fin is relatively thin and easily deflected outwardly, the amount of outward deflection produced during closing may be substantially greater than is possible between thicker elements such as the rib and the surface of the spoon hole. Accordingly, a sealed, but not objectionably tight, closing is eflected. Because of the different inclines of the rib and the exposed edge surfaces, a slight gap or channel 51 (see FIGS. 3 and 9) may be left above the fin.

The straight sections 23 and 38* on the rib 38 and the top adjacent the hinge 25 need not be positioned for a tight, press fit as was the case in the previous construction. Instead, as illustrated in FIGS. 6 and 8, these surfaces actually may be spaced apart above the sealing fin 44 because the latter seals against the rib well below the level of the flap 12. The elongated clearance spaces shown herein have been built into the dies intentionally in order to improve die maintenance. Preferably, the forward ends of the straight sections are very close together at 52 (FIG. 9) and then diverge toward the hinge. The sealing fin has straight end portions in this area. For a neater appearing product, the resulting clearance along each side of the flap should be covered by a laterally extending wing 53 on each side edge 28 having the same shape as the clearance space, as viewed from above.

With the fin 44 sealing against the outer side of the rib 38 completely around the latter, and the hinge web 25 forming a seal between the straight side 21 of the opening 11 and the rear edge of the flap 12, the only possible leakage areas are between the ends of the rib and the rear side of the opening. Leakage in these areas would permit the contents of the can to escape into the unsealed channel 51 above the fin and eventually to leak out around the flap. Herein, such leakage is prevented by means of the sealing elements 47 and 45 which take the form of a pair of blocks integrally molded on the rear side in alinement with the ends of the ribs, and thin, finlike projections or ridges molded on the rib ends to extend rearwardly from the rib, when free, a distance greater than the spacing of the ends from the front faces of the blocks, thereby forming a linear seal at 54 (see FIG. 6) extending from the underside of the hinge web 25 downwardly to below the level of the seal between the fin and the rib.

As shown in FIGS. 2 and 3, the upper end of each sealing ridge 45 is joined to the hinge web 25 and the lower end preferably is adjacent the underside of the rib 38. The thickness of the ridge is somewhat exaggerated in FIGS. 4 and 5, the important thing being suificient resilient compressibility to insure that a pressure seal is formed and maintained to the level of the seal between the fin and the rib. For this purpose, the ridge may be little more than an elongated, rearwardly projecing flash of plastic on the end of each rib. The blocks 47, of course, provide abutment surfaces that are offset forwardly from the rear side 21 to lie close to the vertical plane of the rear edge of the flap 12 and the ribs, thereby minimizing the required length of the finlike ridges. It will be seen that the wings 53 are for improved appearance only, the contents of the can being effectively sealed against escaping into the clearance spaces covered by the wings.

To form the seal around the sifter flap 18, a second fin 55 (FIG. 7) extends from the straight side 22 of the sitter hole entirely around the perforated sifter 19 and is integrally joined at both ends to the straight side, the lower, free edge portion of the fin being inclined inwardly and downwardly to seal against the sitter in the area above the holes 20 when the flap 18 is closed. Finlike ridges 57 on the ends of the sifter are positioned to be compressed against blocks 58 alined with the ends and thereby complete the seal around the flap.

It will be seen in FIG. 7 that a continuation 59 of the arc of the sitter 19 intersects the fin 55 well above its lower edge so that swinging of the flap 18 and the sitter into the opening 17 brings the lower edge into interfering engagement with the fin to deflect the same laterally outwardly all the way around the sitter, The lower edge of the sitter preferably is beveled at 60 to facilitate the initial movement into the opening, past the latching shoulder 43 and beyond the tin. As shown in FIG. 1, the locking lips 41 are formed adjacent the lower edge of the fin and extend radially outwardly to abut against the lower edge of the fin as the flap is opened after the lips have been forced past the =fin. Thus, the fin serves as a locking abutment as well as a sealing element providing the same fullperipheral, resilient sealing action provided by the fin 44 around the spoon-hole opening 11. Clearances and wings of the type shown in FIG. 8 preferably are provided for the sitter flap as well.

From the foregoing, it will be seen that the improved closure may be made in the same basic, single-piece molded form as the closure disclosed in my prior patent with both a spoon opening and a sitter opening and hinged, integral flaps for closing the openings. In addition, however, the integrally molded fins 44 and 55 provide highly effective seals around the full length of the two depending ribs 19 and 38 by pressing yieldably and resiliently against the ribs after the latter are pressed into the fins as the flaps are closed. Because of the easy yieldability of the fins, it is possible to provide a suflicient degree of interference fit between the ribs to insure effective seals even after a substantial amount of wear in the molds occurs in service use.

In addition, the provision of the simple compressible sealing elements on the ends of the ribs and the adjacent surfaces of the hinge walls of the two openings eliminates leakage around the ribs, these elements cooperating with the fins and the hinge webs to complete the full peripheral seals around the flaps. As a further advantage resulting from this approach to the sealing problem, it is permissible to provide intentional clearances between the ribs and the side surfaces of the openings, spanned by the fins so that no leakage can occur and preferably masked by the wings 53 for better appearance of the closure.

I claim as my invention;

1. In a single-piece closure of molded plastic for covering one end of a container and having a generally flat top defining a dispensing opening having a substantially straight rear side, a closure flap having a substantially straight rear edge integrally joined to said top along said rear side to form a hinge for swinging of the flap between open and closed positions, a depending rib on the underside of said flap extending from said rear edge at one end of said hinge forwardly and around the free edge portions of the flap and back to said rear edge at the other end of said hinge, and a side surface on said top defining the remaining sides of said opening and extending forwardly from said rear side at said one end around said rib and back to said rear side at said other end whereby said rib fits downwardly into said opening when said flap is in said closed position, the improvement comprising, a thin and resiliently flexible sealing fin formed by an elongated strip of said plastic extending forwardly from said rear side at said one end along said side surface and back to said rear side at said other end, said strip having an upper edge integrally joined to said side surface and spaced below said top, and a depending laterally flexible lower edge portion spaced inwardly from said surface and positioned, when free, across the path of said rib during movement of said flap into said closed position to engage the rib and yield laterally and be expanded outwardly as the flap is closed and thereafter press resiliently against the full length of the rib, and means forming seals between said rear side and the ends of said rib when said flap is closed.

2. A single-piece closure as defined in claim 1 in which said means comprise resiliently compressible elements on said rib ends projecting rearwardly from the latte when said flap is closed, and opposed abutment surfaces on said rear side positioned for interfering engagement with said elements from said hinge to the level of sealing engagement of said fin and said rib adjacent said rear side.

3. A single-piece closure as defined in claim 2 in which said rear edge of said flap is spaced forwardly from said rear side of said opening and integrally joined thereto by a flexible web of said plastic forming said hinge, and said abutment surfaces are the front faces of blocks molded integrally with said rear side in alinement with said rib ends, said front faces being spaced less than a predetermined distance from said ends when said flap is closed and said elements projecting away from said ends, when free, a distance greater than said predetermined distance.

4. A single-piece closure as defined in claim 3 in which said elements are thin, finlike ridges on said rib ends extending from said hinge to adjacent the lower edge of said rib.

5. A single-piece closure as defined in claim 1 in which said lower edge portion is joined at each end of said strip to said rear side and is inclined downwardly and inwardly relative to said side surface, said rib extending downwardly into said opening at a lesser slope than the incline of said lower edge portion thereby to telescope into said strip with a wedge fit along the full length of the rib.

6. A single-piece closure as defined in claim 5 in which said opening is of generally segmental shape, said side surface being a curved upright wall terminating at each end in a section extending transversely of said hinge, and said rib having a corresponding shape telescoping closely within said curved wall and said straight sections, said strip having a curved portion joined to said curved wall and straight portions joined to said straight sections and to said rear wall.

7'. A single-piece closure as defined in claim 1 further including latching means on said flap and said side surface along the forward portions above said fin thereof for interlocking releasably between said fin and said flap when the later is in said closed position thereby to latch the flap releasably in the closed position.

8. A single-piece closure as defined in claim 5 in which said rib is formed with sifter holes spaced below said fiap and below the level of engagement of said fin with the rib when the flap is closed, whereby said fin seals against said rib above said sifter holes.

9. A single-piece closure as defined in claim 8 in which said rib is of part-spherical shape and said side surface is curved to fit closely around the rib in all positions ofsaid flap in which the rib is within said opening, said rib having an arc of curvature about said hinge intersecting said fin above said lower edge.

10. A single-piece closure as defined in claim 9 further including at least one abutment projecting radially outwardly from the lower edge of said rib to resist movement of said rib out of said opening after said abutment has been forced downwardly past said fin.

11. A single-piece closure as defined in claim 1 in which said opening is of generally segmental shape, said side surface being a curved upright wall terminating at each end in a substantially straight end section extending transversely of said hinge, and said rib is of corresponding shape telescoping closely within said curved Wall and also terminating in straight end sections, said rib end sections diverging from said wall end sections from the forward end portions thereof toward said wall to define elongated clearance spaces above said fin, and said flap having wings thereon covering said spaces.

" 12. In a single-piece closure of molded plastic for covering one end of a container and including a top having edge surfaces defining a dispensing opening, a closure flap having one edge integrally joined to said top along one side of said opening by a flexible hinge web, and a side surface on said flap shaped to fit closely within said opening from one-end of said hinge web around the opening to the other end of the hinge web, when the flap is closed, the improvement comprising, a thin and resiliently flexible sealing fin formed by a strip of said plastic extending around said opening along said side surface from said one end to said other end, said strip having an upper edge integrally joined to said top within said opening and a depending, laterally flexible free edge portion positioned across the path of said side surface during closing of said flap to engage said side surface and yield laterally outwardly, thereafter to press resiliently against the full length of said side surface.

13. A single-piece closure as defined in claim 12 in which said strip is inclined downwardly and inwardly across said path and said side surface is inclined at a lesser slope to telescope into the strip with a wedge fit and form a seal along a line spaced above the lower edge of the strip.

14. A single-piece closure as defined in claim 12 further including means forming a pressure seal between said flap and said one side of the opening at each end of said hinge web from the web downwardly to a level below the level of engagement of said strip with said side surface.

15. A single-piece closure as defined in claim 14 in which said side surface is the outer side of a rib depending from saidflap, and said seal-forming means include finlike compressible ridges on the ends of said rib, and surfaces on said rear side positioned for interfering sealing engagement with said edges when said flap is closed.

References Cited UNITED STATES PATENTS 2,852,054 9/1958 Motley 220 31 X 3,155,285 11/1964 Van Baarn 222480X 3,262,606 7/1966 Waterman 222-480 X 3,322,308 5/1967 Foster 222-480 GEORGE E. LOWRANCE, Primary Examiner US. Cl. X.R. 220; 222-480

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