Apparatus For Forming Treaded Closures

Abstract

Ductile metal blanks closed at one end and having cylindrical skirts are rotated in contact with forming tools under sufficient pressure to shape, lance and score the cylindrical skirt. The tools may be spread along a path to deform different parts of the skirt at different path locations. The tools form an outwardly extending circumferential bulge in each skirt and simultaneously score a series of slots around the skirt in the bulge and score the external surface of the skirt between the lanced portions and the open end of the skirt. The scores are aligned in specific angular orientation relative to the orientations of the lanced slots.

Parent Case Text

This is a continuation in part of my co-pending applications Ser. No. 117,512 filed Feb. 22, 1971, now abandoned and Ser. No. 233,599 filed Mar. 10, 1972, now abandoned.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of machines to form ductile metal blanks into closure blanks for later attachment to containers having threaded necks. In particular, the invention relates to machines in which there is relatively high-pressure rolling contact between each cylinder and a series of forming tools to produce an outwardly expanded circumferential region of the skirt of each blank, to put a series of angularly displaced slots around the skirt in the outwardly expanded region, and to put a series of similarly angularly displaced scores in the skirt between the outwardly expanded region and the free end.

2. The Prior Art

The closure described in the aforesaid applications is generally similar to the pilfer-proof closure presently on the market. In its finished condition as addached to a container, the pilfer-proof closure is a cylinder closed at one end and with the cylindrical wall deformed into a helical thread adjacent the closed end. At the other end of the threaded section, is a series of elongated slots that leaves the open end of the skirt attached to the threaded part only by narrow bridges of the ductile metal of which the closure is formed. The open end of the skirt is deformed to fit around and under an integral collar on the neck of the container. In order to remove the closure from the container, enough torque must be applied to break the metal bridges and separate the skirt into two portions, one of which remains on the container.

Containers with pilfer-proof closures on them are satisfactory for single usage; but if they are to be used again, the pilfer-proof ring must be removed before attaching a new closure. It is difficult to remove this ring, and the cost of doing so detracts seriously from the advantage of using this type of closure. Yet the ecological pressure for recycling is too great to be ignored and, as a result, consideration has been given to a different type of closure.

One type of closure that has been proposed as a means of avoiding leaving the pilfer-proof ring on the container after the main part of the closure has been removed is described in U.S. Pat. No. 3,601,273. In that patent, the lancing is done in such a way that alternate bridges are relatively wide and the remaining bridges are relatively narrow. The end portion skirt is vertically scored from the inside with fewer scores than the number of bridges and with no attempt to align the scores in any particular position relative to the bridges. When such a closure is removed from the neck of a container, it is expected that the vertical scores will rupture allowing the sectors of the skirt to be cammed outwardly by the shoulder of the container. However, as shown in FIG. 4 of that patent, an extremely dangerous rupture of certain of the bridges may take place, causing sharply pointed sections of the skirt to project outwardly so that anyone attempting either to loosen or tighten the closure may be severely cut. The skirt is most likely to break out this way when the scores happen to be aligned with the narrow bridges. The dangers of such a structure are readily apparent to consumers. In addition, there is a growing tendency for agencies of the government having to do with product safety to become concerned about items such as this.

The improved closure described and claimed in my aforesaid applications looks much the same as the prior pilfer-proof closure, but the end of the skirt that previously formed the pilfer-proof ring has a plurality of longitudinal scores in it so that when an attempt is made to unscrew the closure from a container, the bridges that join the threaded portion to the outer end of the skirt will not be broken but instead the scores will open up and allow this portion of the skirt to be removed along with the remainder of the closure.

In particular, in my aforesaid applications, I have pointed out the importance of scoring the external surface of the skirt with the same number of scores as bridges and of aligning these scores around the skirt of the closure in a specific angular relationship with respect to the bridges.

It is one of the objects of the present invention to provide improved means for forming, lancing, and scoring closure blanks.

SUMMARY OF THE INVENTION

The closure blanks are initially formed as short cylinders of ductile metal closed at one end. They may be formed by a drawing process but the technique of forming them does not comprise part of this invention. The present invention has to do only with the mechanism for shaping these closed cylinders so that they are ready to be applied to a threaded container neck.

In order to form the closure blanks with external scores and with lanced slots arranged so that there is a predetermined angular relationship between each of the scores and the bridge between each pair of the lanced slots, the same tools must include lanced blades and scoring blades. The lanced blades are arranged in a plane which is transverse to the axis of the cylindrical sections of each of the blanks and the scoring blades are located parallel to the axis of the closure blanks. It is advantageous for the scoring blades to be located slightly below the plane of the lancing blades with each scoring blade angularly centered between a pair of lancing blades.

The closed cylinders are mounted by automatic means on the ends of a series of spindles which pass an entrance point in succession. Each spindle has a smaller diameter than the blank and a smaller diameter than any formed part of the final closure blank so that there will be no difficulty getting the closure blank on or off its respective spindle. The configuration of each spindle conforms to the inner wall of the final closure blank so that as each spindle with the blank mounted on it is rotated across the surface of suitable forming tools, the cylinder wall of the blank will be pressed into the desired configuration. As indicated in my prior patent applications the configuration includes an outwardly extending bulge that is located on the cylindrical part of each blank intermediate the ends thereof but usually closer to the open end. In addition, the configuration includes the elongated slots lanced through this outward bulge, and it also includes longitudinal scores that extend approximately from the bulge to the open end of the cylindrical skirt of the closure blank.

The tools that press against the outer surface of the cylindrical part of the blank are usually arcuate in form and there is a gearing connection between the support for the tools and the spindle such that the blanks will be rolled by the spindle across the forming surface of each of the tools without rubbing the cylindrical surface across the face of the tool. Thus the ductile metal will be pressed into the desired shape but will not be abraded.

In one embodiment, the radius of the arcuate surface of the forming tools is relatively small and is such that the perimeter of the forming tools is about twice as long as the circumference of the cylindrical part of the blank. In this embodiment both the spindle and the forming tool must be rotated by meshed gears to provide the necessary non-dragging movement of the blank relative to the surface of the forming tool. In another embodiment the radius of the forming tools is substantially greater than in the first embodiment and the forming tools may remain stationary while the spindles move along an arcuate path and simultaneously rotate on their own axes to roll each of the blanks across the surface of the forming tools in the desired way.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a closure scored in accordance with the present invention and fitted on the neck of a container.

FIG. 2 is a cross-sectional view along the line 2--2 of the container and closure in FIG. 1.

FIG. 3 is a side elevational view of the closure in FIG. 1 prior to the time it is applied to a container and has threads formed in it.

FIG. 4 is a perspective view of a lancing and scoring tool for use in the manufacture of the closure in FIG. 6.

FIG. 5 is a plan view of a lancing and scoring blade for use in the tool in FIG. 7.

FIG. 6 is a cross-sectional view of the lancing and scoring tool in FIG. 5 at one point of contact with a closure.

FIG. 7 is a fragmentary cross-sectional view corresponding to FIG. 6 but illustrating a different point of contact between the closure and the scoring blade.

FIG. 8 is a fragmentary cross-sectional view of the closure in FIG. 1.

FIG. 9 is a simplified top elevational view of a machine for knurling, scoring and lancing the closure blank of FIG. 3.

FIG. 10 is a side elevational view of a modified form of machine for making the closure blanks.

FIG. 11 is a cross-sectional view of one station in the machine of FIG. 10.

FIG. 12 is a cross-sectional view of another station in the machine of FIG. 10.

FIG. 13 is a plan view of one of the tools in FIG. 12.

FIG. 14 is a front elevational view of the tool in FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a bottle closure 11 having a flat top 12 and a generally cylindrical skirt extending downwardly from the perimeter of the top. This closure is preferably made of ductile material, such as a deformable aluminum base alloy having a thickness of about 0.010 to 0.011 inch. At the upper end of the skirt is a knurled band 13 that provides better frictional engagement with the closure so that the latter can be more easily unscrewed from a container 14. Below the knurled band 13 the skirt has been deformed into a threaded section 16 and at the lower end of the threaded section is an outwardly extending bulge 17 formed by pressing the sheet metal material of the skirt outwardly by a predetermined amount. The extent of the outward bulge will be described in greater detail hereinafter. The bulge may include, at its upper side, a second knurled band 18. Between the upper and lower limits of the bulge 17 are several lateral slots 19, each formed by lancing a short tongue of the skirt material inwardly, preferably pivoting each of the tongues about the lower edge thereof. The section of the skirt that remains between the slots 19 are bridges 21 that join the upper part of the closure 11 to a pilfer-proof section 22 that forms the lowermost part of the skirt.

In accordance with this invention, a plurality of vertical scores 23 are formed in the pilfer-proof section 22, and in this embodiment each of the scores 23 is directly in line with and below the center of each of the bridges 21. The lowermost end of the skirt is tucked under a shoulder (not shown) on the neck of the container 14, and, if desired, a plurality of stripes 24 may be printed on the pilfer-proof section to assist in visually indicating when the scores 23 have been broken in removing the closure from the container.

As will be described in greater detail hereinafter, when the closure 11 is unscrewed from the container 14, each of the scores 23 ruptures so that the pilfer-proof section breaks into small sectors. Each of the bridges 21 forms a hinge for the ends of the pilfer-proof sections 22 below that bridge.

FIG. 2 shows a cross-sectional view to illustrate the arrangement of the bridges 21 and indicate that there are eight of such bridges. It is possible to use other numbers of bridges, but I have found that the use of eight bridges allows the closure to be removed without having to deform the pilfer-proof section as much as would be necessary if there were a smaller number of bridges. At the same time, it is easier to provide eight bridges than to try to fit nine or more around the closure 11.

FIG. 3 shows the closure blank 11a of FIG. 1 prior to the time it is placed on a container. Thus, the threads 16 of FIG. 1, which are formed during the process of sealing the container, have not yet been incorporated. However, the knurled band 13 and, particularly, the bulge 17, the knurled band 18, the slots 19, and the bridges 21 are shown somewhat more clearly in FIG. 3 than in FIG. 1. The slots 19 are formed in such a way that the metal is bent inwardly from the top edge of the slots rather than from the bottom as in FIG. 1. In addition, the pilfer-proof section 22 is shown as being slightly conical with an included angle of approximately 6.degree. to facilitate placing the closure on a container to be sealed. The scores 23 have also been formed by the time the closure 11 reaches the stage of manufacture shown in FIG. 3.

FIG. 4 shows a device 26 constructed to lance and score caps in accordance with the present invention. The device 26 is mounted on a shaft 27 and comprises a plurality of lancing blades 28 that form the slots 19 in FIG. 1. Simultaneously with the lancing of the slots, the device 26 scores the vertical marks by means of vertical scoring blades 29. Since these scoring blades are fixedly positioned with respect to the lancing blades 28, the location of the scores relative to the bridges 21 in the closure 11 in FIG. 1 is fixed. This device 26 can be used to provide the scores 21 and the slots 19 as shown in the closure 11 in FIG. 1. The scoring blades 29 may be made longer so that they extend up between the lancing blades 28, but the scoring blades would then have to be shaped to conform to the bulge 17, and that would be difficult.

The lancing and scoring blades and the mechanism are shown in more detail in FIGS. 5-7. FIG. 5 shows one form of the lancing and scoring blade adapted for use in certain machines for forming the closures. Only about half of the perimeter of the lancing blade 31 is provided with lancing edges 32. For the sake of convenience, the structure shown in FIG. 5 is actually made up as a tool pack, and individual scoring blades 33 are fitted in slots centered between pairs of the lancing edges 32. The tool pack is formed as an annular structure with a central aperture 34 to fit on a support in a capping machine. The tool pack also is provided with apertures 36 that allow the tool pack to be assembled with a specific relationship between the lancing edges 32 and the scoring blades 33.

FIG. 6 shows a closure blank 36 supported on a rotating member 37 in a forming machine. The member 37 has a knurling ring 38, a cylindrical section 39, a pair of discs 41 and 42 that produce the outward bulge 17 in the closure blank 36 and also cooperate to produce the knurled band 18 and the slots 19. Below the disc 42 is a tapered section which may comprise two discs 43 and 44 to form the slightly conically tapered pilfer-proof section 22 of the closure 36. Below the disc 44 is a limit ring 46 that prevents the closure material from being squeezed too much while the closure 36 is being formed.

Cooperating with the member 37 to form the closure 36 is a group of discs, including a knurling ring 47 that cooperates with the ring 38 to form the upper knurled band 13. Below the ring 47 is another cylindrical ring 48, the lower side of which is machined away to cooperate with the disc 41 in forming the bulge 17 and the knurled band 18. Below this is the lancing blade 31, one of the edges 32 of which is shown pressing a tongue 49 into the bulge 17. Below the lancing blade 31 is a section that holds the scoring blades 29 and below that is a disc 51 that presses against the ring 46 when the closure 36 is being formed. As shown, each of the scoring blades is at an angle that corresponds to the taper in the disc 44.

FIG. 7 shows a different cross-sectional view of the closure forming apparatus and particularly illustrates the way that one of the scoring blades 29 presses into the pilfer-proof section 22 of the skirt of the closure 36. The blade 29 may be set so that it presses approximately 0.006 inch into the 0.010 inch thickness of the closure metal.

Another type of closure forming machine is shown in FIG. 9. In this machine, unformed closure blanks 52 enter the machine along the direction of the arrow 53 up a ramp 54. Each of the closures 52 has its open end facing upwardly and it is picked up by an arbor, or spindle 56, which may be generally similar to the member 37 in FIG. 9. The arbor 56 rotates as shown by the arrows 57 and moves in a circle as indicated by the arrow 58 to push the closure blank 52 along a circular shelf 59. A raised central disc 61 has several forming stations set into it. The first of these stations is indicated by reference numberal 62 and forms one of the knurling bands, for example the knurling 13 shown in the closure in FIG. 1. In order to form this knurling band, the arbor 56 revolves the closure blank 52 against the knurling surface of the station 62.

Subsequently, the closure blank 52 reaches a second station 63, which has a configuration suitable for forming the bulge 17 and the second knurling band 18 as shown in FIG. 1. Thereafter, the closure blank 52 is brought around to the third station, which includes a lancing blade 66 with lancing edges 67. Scoring blades 68 are fixedly located with respect to the lancing edges 67 to place the scores as desired and preferably centered with respect to the bridges formed by the gaps between adjacent lancing edges 67. Thereafter, the closure blank 52, which is then in the same configuration as the closure 11 in FIG. 1, leaves the shelf 59 by way of a downwardly sloping ramp 69.

FIG. 8 is a fragmentary cross-sectional view showing the closure 11 of FIG. 1 applied to a glass bottle 14. As may be seen, the bottle has a shoulder 76 and the pilfer-proof section 22 of the closure 11 is folded under this shoulder. Above the pilfer-proof section 22 is shown one of the tongues 32 formed by the lancing blade in the apparatus just described. It is important to note that the bulge 17 in the closure 11 extends far enough out so that the inwardly directed tongues 49 do not come into contact with the wall of the container 14 above the shoulder 71. Thus when the closure 11 is removed from the container and replaced on the container, the tongues 49 do not scrape on the container surface. One effect of such scraping would be to leave an undesired metallic deposit which, in the case of certain chemicals frequently found in beverages, could lead to an unsightly dark band. Another adverse effect of such contact between the tongues 49 and the container 14 is an increase in the torque required to remove the closure from the container. Thus, the bulge 17 must extend outwardly farther than the tongues 49 extend inwardly.

FIG. 10 shows in greater detail a forming machine similar to that in FIG. 9. The machine in FIG. 10 comprises a substantially flat plate 72 having a chute attached to it to provide means for feeding closure blanks 52 into the machine. Parallel to the plate 72 is another plate 74 on which a number of arbors, or spindles, 76 are mounted. Each of the spindles 76 is attached to a shaft 77 which has a gear 78 mounted on it. The gear 78 meshes with a large stationary gear 79 and the plate 74 is arranged to be rotated by a belt 81 driven by a motor (not shown). Rotating the plate 74 causes the spindles 76 to move in a circle and the engagement between the gear 78 attached to each spindle and the stationary gear 79 causes each spindle to rotate on its own axis.

As the spindles 76 move in a circle they pass in succession three forming stations 82-84. The relative pitch diameters of the gears 78 and 79 and the relative radii of the spindles 76 and the convex arcuate surfaces, or edges, of the tools in the stations 82-84 are such that the spindles in effect roll across the surfaces of the stations without sliding. More specifically, as each of the closure blanks 52 in turn moves down the chute 73 and falls on to the top of one of the spindles 76, the cylindrical skirt portion of the closure blank is rolled in succession across the arcuate convex surfaces of the stations 82-84. After the spindles 76, each loaded with one of the closure blanks 52, passes beyond the third station 84 by a sufficient distance, the spindle eventually moves opposite an arcuate slot 86, and automatic means directs air through hollow channels such as the channels 87 in the spindles 76 and blows the formed closure blank 52 off of the spindle and into a hopper (not shown).

FIG. 11 shows a closure blank 52 being formed by either the first or second station 82 or 83 in the machine of FIG. 10. The spindle includes a shaft 77 with the gear portion 78 meshing with the stationary gear 79. The shaft 77 has a shoulder 87 on which rests a support ring 88. This ring also has a shoulder 89 on which rests an annular shim 91 that supports an axially compressable rubber, or elastomeric ring 92. A hollow tubular member 92 within the ring 91 and around the shaft 77 helps to locate the ring. The member 92 also acts as an axial guide for a centering ring 93 that has an internal tapered, or reentrance surface 94. This surface engages the lower tapered surface 96 of a floating ring 97. This ring has an internal cylindrical surface 98 with a larger diameter and the external surface 99 of the member 92 so that the ring 97 can move laterally with respect to the member 92.

Above the ring 97 are other forming rings that form the expanded bulge 17, the knurled bands 13 and 18 and a cylindrical portion there between. These knurled bands are formed in either the first or second stations by pressure of the spindle 76 against the convex arcuate surface of the tools in the forming stations 82 and 83.

The purpose of the rings 93 and 97 is to recenter the closure blank 52 with respect to the spindle 76 after the forming operation is completed. While this does not take place after the spindle has moved past the third station 84 it will be evident FIG. 11 that the lower surface of the bulge 17 which extends almost radially inwardly can catch on the rings above it in the spindle unless the closure blank 52 is brought back to a central location. When the spindle 76 rolls the closure blank 52 across the forming surfaces, the pressure of the forming surfaces against the skirt material of the closure member 52 produces the distortion of the skirt member that results in the knurled bands and the slight outward flare of the lowermost end of the skirt. This flare, is, as stated previously approximately 6.degree. and is formed between a plate 112 and the outer surface 102 of the ring 97. This pressure forces the ring firmly against the surface 99 of the member 92. The sloping surface 96 of the ring 97 presses against the surface 94 of the ring 93, which can only move axially downward. This movement of the ring 93 compresses the ring 91 so that when the spindle 76 moves beyond the third station 84 and there is no longer any radial pressure on the ring 97, the ring 91 pushes the ring 93 upwardly and this in turn exerts a force on the surface 96 of the ring to center the latter ring. In so doing it pushes the closure blank 52 out of engagement with the spindle. In this instance it would be to the left. The closure blank 52 is then free to be ejected from the spindle.

FIG. 12 shows the tool stack of the station 84. In this instance the station has a lower arcuate member 103 on top of which is a plate 104 that serves as a backup plate for a scoring blade 106. This scoring blade has an edge 107 that butts against the edge of the arcuate plate 104 to fix the position of the edge of the scoring blade 106.

Above the plate 104 is another arcuate plate 108 that has slots in it to receive a series of scoring blades 106. On top of the plate 108 is the lancing blade 109 and above that is another arcuate plate 111 that completes the tool pack.

In the event that the spindle does not pick up one of the closure blanks 52, means are provided to keep the external surface 102 of the ring 97 from engaging the scoring blades 106. This includes an arcuate plate 112 that fits into a recess in the upper front edge of the member 103 and is biased outwardly by a spring 113. A small cylinder 114 holds the spring 113 in place in a channel 116 and presses against the rear edge of the plate 112. There is a small gap between the rear edge of the plate 112 and a forward facing surface 117. If the spindle has no closure blank 52 on it, the ring 97 can force the plate 112 back against the surface 117 but can go no farther. The dimensions are such that, in this condition, there is still a clearance between the edge of the blades 106 and the surface of the ring 97.

FIGS. 13 and 14 show the member 103 and the plate 112. As may be seen, the plate has two rearwardly facing projections 118 and 119 which extend into recesses 121 and 122 in the upper surface of the member 103. In order to apply uniform pressure to the plate 112, there are three springs 113 in their respective channels.

As may be seen particularly in FIG. 14 the channels 116 are drilled near the upper surface of the member 103 and are large enough to accommodate springs 113 of reasonable size. The channels extend into a recessed area in the upper front surface of the member 103 in which the plate 112 is located. Thus the cylinders 114 extend up into contact with the rear surface of the sliding plate 112. While this sliding structure has an advantage in preventing contact between the scoring blades 106 and the ring 97, it may be replaced by a rigid member that combines the lower part of the member 103 and a fixed plate in place of the sliding plate 112 if the remainder of the spindle structure is such that there can be no contact between any part of the spindle and the scoring blades 106.

Claims

What is claimed is:

1. Means for lancing slots around a skirt portion of a screw-on closure and for scoring an edge portion of said closure said apparatus comprising:

A. a wheel having a plurality of lancing edges extending radially therefrom and all lying in a common plane perpendicular to the axis of said wheel;

B. a plurality of scoring edges rigidly placed relative to said lancing edges and extending parrallel to the axis of said wheel; and

C. means for providing relative rolling movement of each of said skirt portions across said lancing and scoring blades, whereby said lancing edges lance through from the outside of said skirt and said scoring edges press only part way through from the outside of said skirt.

2. The apparatus of claim 1 in which said scoring blades are angularly oriented between adjacent pairs of said lancing edges.

3. The apparatus of claim 1 in which said scoring edges are limited to a region adjacent to, and on one side of, but not including, said plane of said lancing edges.

4. The apparatus of claim 3 comprising, in addition:

A. a first support plate having a convex arcuate edge and substantially radial slots in such edge, each of said scoring edges comprising an edge portion of a scoring blade fitting into a respective one of said slots; and

B. a second plate comprising an arcuate edge concentric with said arcuate edge of said first plate and having notches therein corresponding in number to the slots in said first plate, sections of said edge of said second plate between said notches comprising said lancing blades, said first and second plates being rigidly mounted together with a predetermined angular relationship between said slots in said first plate and said notches in said second plate, the portions of said edge of said second plate between said notches comprising said lancing blades.

5. The apparatus of claim 4 in which said plates are angularly oriented with respect to each other so that each of said slots is substantially centrally located with respect to a corresponding one of said notches.

6. The apparatus of claim 5 comprising:

A. an additonal member having an arcuate edge concentric with said arcuate edges of said plates, said first plate and said second plate being rigidly attached to said member with said first plate between said member and said second plate; and

B. an arcuate lip concentric with said edges and attached to said member and extending beyond said edge of said member to limit pressure of said closure against said blades.

7. Means for lancing slots around a skirt portion of a screw-on cap for scoring an edge portion of said cap, said apparatus comprising:

A. a wheel having a plurality of lancing blades extending radially therefrom and all lying in a common plane perpendicular to the axis of said wheel; and

B. an equal plurality of scoring blades extending parallel to the axis of said wheel to a relatively lesser radial distance than said lancing blades and each of said scoring blades being angularly disposed between a pair of said lancing blades and spaced therefrom.

8. The apparatus of claim 7 in which each of said scoring blades is directly between adjacent pairs of said lancing blades and extends across said common plane.

9. The apparatus of claim 7 in which said scoring blades are limited to a region adjacent to, and on one side of, but not including, said plane of said lancing blades.

10. The method of lancing slots around a skirt portion of a screw-on cap and of scoring an edge portion of said cap in one operation, said method comprising rolling said skirt portion in non-slipping engagement with a plurality of lancing blades extending radially from a central axis and all lying in a common plane perpendicular to said axis, and an equal plurality of scoring blades extending parallel to said axis to alternately lance and score said skirt portion as said rolling progresses, whereby each score is separated from, and does not intersect with, each lancing.

11. The method of claim 10 in which said cap is acored to a depth of at least approximately 70 percent of the thickness of the material of said cap.