MXPA97009042A - End of can and method to fix it to a body of l - Google Patents

Abstract

The present invention relates to a can end comprising a peripheral cover hook (23), a wall for the mandrel (24) depending on the inner part of the cover hook, an annular reinforcing projection concave outwards (25). ) extending radially inward from the wall for the mandrel, and a central panel (26) supported by an internal portion (27) of the reinforcing projection, characterized in that the wall for the mandrel (24) is inclined with respect to a axis perpendicular to the outside of the central panel (26) in an angle C between 30 ° and 60 °, and the radius in the concave cross-section of the reinforcing projection (25) is less than 0.75 millimeter

Description

EXTREME OF CAN AND METHOD TO FIX IT TO A BODY OF CAN This invention relates to an end wall for a container, and more particularly, but not exclusively, to an end wall of a can body, and to a method for securing the end wall to the can body by means of a line double union. The Patent of the United States of North America Number 4,093,102 (KRASKA) discloses can ends comprising a peripheral cover hook, a mandrel wall depending on the inner part of the cover hook, an outwardly concave annular reinforcing projection, extending radially inward from the wall for the mandrel, and a central panel attached to an inner wall of the reinforcing projection by an annular outwardly convex projection. It is said that this can end contains an internal pressure of 6.3 kg / cm2, by virtue of the inclination of the wall for the mandrel, the external wall of the projection and the internal wall of the projection, with respect to a line perpendicular to the central panel. The inclination of the wall for the mandrel D ° is between 14 ° and 16 °, the inclination of the external wall is less than 4 °, and the inclination of the internal wall C ° is between 10 ° and 16 °, leading towards the outward convex outward. We have discovered that improvements can be made in the use of metal by increasing the wall inclination for the mandrel, and limiting the width of the protrusion against the formation of peaks. The Patent of the United States of North America Number 4,217,843 (KRASKA) describes an alternative design of a can end, wherein the countersink has internal and external flat walls, and a bottom radius that is less than three times the thickness of the metal. The can end has a wall for the mandrel that extends at an angle of approximately 24 ° with respect to the vertical. Conversely, our European Patent Application Number EPO340955A discloses a can end where the wall for the mandrel extends at an angle of between 12 ° and 20 ° with respect to the vertical. Our European Patent Number 0,153,115 discloses a method for manufacturing a suitable can end for closing a can body containing a beverage, such as beer or soda. This can end comprises a peripheral flange or cover hook, a wall for the mandrel that depends on the inner part of the cover hook, an outwardly concave reinforcing projection extending radially inward from the wall for the mandrel, from a thickened wall junction for the mandrel with the projection, and a central panel supported by an internal portion of the reinforcing projection. These can ends are typically formed of a previously lacquered aluminum alloy, such as an aluminum-magnesium-manganese alloy, such as alloy 5182. Our published International Patent Application No. W093 / 17864 discloses a suitable can end for a can of beverage, and formed from a laminate of aluminum / manganese alloy coated with a joining line of semi-crystalline thermoplastic polyester. This polyester / aluminum alloy laminate allowed the manufacture of a can end with a narrow, and consequently strong, reinforcement projection in the cheaper aluminum / manganese alloy. These known can ends stop during the double connection by means of an annular flange of the mandrel, the flange being of a width and height to enter the projection against the formation of peaks. There is a risk of abrasive wear if this narrow ring slips. In addition, a narrow annular flange of the mandrel is susceptible to damage. Continuing the development of one can end using less metal, while still allowing a full can to be stacked on the end of another, this invention provides a can end comprising a peripheral cover hook, a mandrel wall depending on the internal part of the wall for the mandrel, an outwardly concave annular reinforcing projection extending radially inwardly from the wall for the mandrel, and a central panel supported by an internal portion of the reinforcing projection, characterized in that the wall for the mandrel is inclined to a perpendicular axis outside of the central panel, at an angle of between 30 ° and 60 °, and the concave protrusion is narrower than 1.5 millimeters (0.060"). Preferably, the angle of the wall for the mandrel with respect to the perpendicular is between 40 ° and 45 ° In a preferred embodiment of the can end, an outer wall of the reinforcing projection is inclined with respect to a line perpendicular to the central panel, at an angle between -15 ° and + 15 °, and the height of the outer wall is up to 2.5 millimeters In one embodiment, the reinforcement projection has an internal portion parallel to an outer portion joined by the concave radius.The proportion of the diameter of the central panel to the diameter of the peripheral ripple is preferably 80 percent or less. The can end can be made of a thermoplastic polymer film laminate and an aluminum foil alloy, such as a laminate of a polyethylene terephthalate film onto a sheet of aluminum-manganese alloy or a ferrous metal, typically less 0.010"(0.25 mm) thick for the packaging of beverages.A coating compound can be placed on the peripheral cover hook.In a second aspect, this invention provides a method for forming a double bond line between a body of can and a can end according to any preceding claim, this method comprising the steps of: placing the corrugation of the end of the can on a flange of a can body supported on a base plate, locating a mandrel inside the wall for the mandrel of the can end to center the can end on the flange of the body of the can, this mandrel having an im truncoconical pulse of an inclination substantially equal to that of the wall for the mandrel of the can end, and a cylindrical surface portion extending away from the impulse surface into the wall for the mandrel, causing a relative movement between the assembly of the can end and the can body, and a roller for the first joining operation, in order to form a joining line of the first operation, and then cause relative movement between the union of the first operation and a second operation roller, to finish a double joining line, the mandrel wall coming to bend during those joining operations, to make contact with the cylindrical portion of the mandrel. Now, different modalities will be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic sketch of the known apparatus for forming a double joining line. Figure 2 is an enlarged sectional side view of a known mandrel and a can end before forming the joint line. Figure 3 is a sectioned view of a fragment of a known double bond line. Figure 4 is a sectional side view of a can end according to this invention, before corrugation of the shore. Figure 5 is a sectional side view of the can end of Figure 4, on a can body, before forming a double bond line. Figure 6 is a similar view of the can end and the body during the first operation of forming the bond line. Figure 7 is a similar view of the can end and the body during the second final operation of forming the bond line to create a double bond line. Figure 8 is a fragmentary section of a detail of the mandrel. Figure 9 is a side view of the cans stacked one on top of the other. In Figure 1, the apparatus for forming a double bond line comprises a base plate 1, an erect part 2, and an upper plate 3. An elevator 4 mounted on the base plate, can be moved towards and away from a mandrel 5 mounted on the upper plate. The upper plate supports a roller of the first forming operation of the joining line 6 on an arm 7 for pivotable movement towards and away from the mandrel. The upper plate also supports a roller of the second joining line forming operation 8 on an arm 9 for its movement towards and away from the mandrel, after which the relative movement between the roller of the first operation and the can end on the mandrel creates a joining line of the first operation. As shown in Figure 1, the mandrel 5 holds a can end 10 firmly on the flange 11 of a can body 12 against the support provided by the elevator plate 4. Each of the roller of the first operation 6 and the roller of the second operation l, are shown free of the mandrel before the active joining line forming profile of each roller is moved in turn to form the corrugation of the can end and the flange of the body to a double joining line as is shown in Figure 3. Figure 2 shows, at an amplified scale, the mandrel 5 and the can end 10. The can end comprises a peripheral ripple 13, a mandrel wall 14 which depends on the inner part of the ripple, a protrusion against the formation of concave outward peaks extending inward from the wall for the mandrel to support a central panel 16. Typically, the wall for the mandrel is turned outward from the vertical, at an angle C of about 12 ° to 15 °. The mandrel 5 comprises a body 17 having a threaded hole 18 that allows it to be attached to the rest of the apparatus (not shown). An annular projection 19 projects from the body 17 of the mandrel, to define, with the end face of the body, a cavity for receiving the central panel 16 from the end of the can. The adjustment of panel 16 on ring 19 may be loose between the panel wall and the mandrel. The external surface of projecting projection 19 extends upwards towards the body, at a divergent angle of approximately 12 ° with the vertical, to join the outside of the body of mandrel 17, which is thinned by an angle A ° of approximately 4 ° with a vertical axis perpendicular to the central panel. The outer wall of the mandrel 5 engages with the mandrel wall in a low position marked "D" within the portion configured at 12 ° of the projection of the mandrel 15. Since the ends of cans develop with projections against the formation of narrower peaks, the protrusion of mandrel 19 becomes narrower and more likely to fracture. There is also a risk of abrasive wear of the end of the can in the pulse position D, which can leave unpleasantly black marks unacceptable after pasteurization. Figure 3 shows a sectioned fragment of a typical double bond line, showing a desirable overlap of the hook of the body 21 and the end hook 20 between the end of the can 10 and the body of the can 12. Figure 4 shows a can end, according to the invention, comprising a peripheral cover hook 23, a mandrel wall 24 extending axially and inwardly from the inside of the peripheral cover hook, a reinforcing projection or against the formation of outwardly concave peaks 25 extending radially inwardly from the wall for the mandrel, and a central panel 26 supported on a panel of the inner portion at 27. The panel wall is substantially erect, allowing any springing of the metal afterwards. the compression. The wall for the mandrel is inclined with respect to an axis perpendicular to the outside of the central panel at an angle C of between 20 ° and 60 °; preferably between 40 ° and 45 °. Typically, the radius of the cross section of the projection against the formation of peaks is approximately 0.5 millimeters. Preferably, the projection against the formation of peaks 25 is of parallel sides; however, the outer wall can be inclined with respect to a line perpendicular to the central panel at an angle between -15 ° and + 15 °, and the height h? of the external wall can be up to 2.5 mm. This can end preferably is made of a metal foil laminate and a polymer coating. Preferably, the laminate comprises an aluminum / magnesium alloy sheet, such as 5182, or an aluminum / magnesium alloy, such as 3004 with a layer of polyester film on one side. A polypropylene film can be used on the "other side" if desired. The typical dimensions of the example of the invention are: d5 Total diameter (already sed) 65.83mm d4 PC diameter of the radius of the joint line panel. 61.54mm d3 PC diameter of the radius of the joint line / mandrel wall. 59.91mm r_ Radius of the junction line / wall panel for the mandrel. 1.27mm r2 Radius of the joint line panel 5.56mm r3 Concave radius on the projection against the formation of spikes. < 1.5mm d2 Maximum diameter of the projection against the formation of peaks. 50.00mm d1 Minimum diameter of the projection against the formation of peaks. 47.24mm h2 Total height of the end of the can 6.86mm h_ Height to the top of the projection against the formation of peaks. 5.02mm h3 Depth of the panel 2.29mm h4 External wall height 1.78mm c Angle of the wall for the mandrel with respect to the vertical. 43 ° From these dimensions, it can be calculated that the ratio of the central panel diameter of 47.24 millimeters to the total diameter of the can end of 65.84 is about 0.72 to 1.

For greater economy, the aluminum alloy is in the form of a metal sheet less than 0.010"(0.25 millimeters) .A polyester film on the metal sheet is typically 0.0005" (0.0125 millimeters). Although this example shows a total height h of 6. 86 millimeters, we have also discovered that useful can ends can be made with a total height as small as 6.35 millimeters (0.25") Figure 5 shows the peripheral flange 23 of the can end 22 of Figure 4, resting on the tab 11 of a can body 12 prior to the formation of a double bond line as discussed with reference to Figure 1. In Figure 5, a modified mandrel 30 comprises a mandrel body 31 having a trunco-conical impulse surface 32 which engages the wall for the mandrel 24 of the can end 22. The trunco-conical pulse surface is inclined outward and axially at an angle substantially equal to the angle of inclination C ° of between 20 ° and 60 °; in this example In particular, a mandrel angle C of 43 ° is preferred.The pulse surface 32 is a little shorter than the wall for the mandrel 24. of the mandrel body. at 33, which rises above the pulse surface 32, it can be inclined at an angle between + 4 ° and -4 ° with respect to a longitudinal axis of the mandrel. As in Figure 2, this modified mandrel 30 has a threaded opening to allow attachment with the remainder of the double bond line forming apparatus (not shown). In contrast to the mandrel of Figure 2, the modified mandrel 30 is designed to initially drive on the wall for the relatively large mandrel 32, without going deep into the projection against the formation of peaks 25. An additional pulse is obtained at the junction of the wall for the mandrel 32 and the cylindrical wall 33, when the wall for the end mandrel 24 is deformed during the first and second joining line forming operations of Figures 6 and 7. The mandrel 30 shown in the Figure 5 has an annular projection of an arcuate cross section, but projecting is designed to enter the wall for the mandrel without scraping or abrading a coating on the end of the can; not to be propelled on the concave projection surface, as shown in Figure 2. It will be understood that the joining line of the first operation is formed using the apparatus described with reference to Figure 1. Figure 6 shows the can end modified and the mandrel during the formation of a joining line of the first operation, shown to the left of Figure 2, as formed by a roller of the first operation 34 adjacent to the peripheral flange interfolded the end of the can and the flange 11 of the body 12. During the relative rotation between the end of the can 22 and the roller of the first operation 34, the edge between the impulse wall of the mandrel 32 and the cylindrical wall 33, exerts a clamping force between the mandrel 30 and the roller 34 to deform the wall for the mandrel from the end of the can as shown. After finishing the joining line of the first operation, the roller of the first operation oscillates away from the joining line of the first operation, and a roller of the second operation 38 oscillates inwardly, to rest on the line of union of the first operation, supported by the mandrel 30. The relative rotation between the roller of the second operation 38 and the joining line of the first operation supported by the wall for the mandrel 30, ends a double joining line, as shows in Figure 7, and leads to the upper part 24 of the wall for the mandrel 24, to lie tight against the neck of the body of the can, in a substantially upright attitude, when the double joining line is tightened by a pressure of tightening between the roller of the second operation 38 and the mandrel 30.

Tin ends according to the invention were made, from aluminum alloy 5182, and an aluminum alloy 3004 / polymeric laminate, sold by CarnaudMetalbox under the trademark ALULITE. Each can end was fixed by a double joining line, to a stretched can body and to the ironed wall (DI), using different angles of the mandrel and wall angles for the mandrel, as tabulated in Table 1, which records the pressure inside a can, where the ends of the can failed: TABLE 1 All the pressures on the non-aged covers are in bar (psig). 5182 is a lacquered magnesium-manganese aluminum alloy. The "ALULITE" used is a laminate of aluminum alloy and polyester film.

The first results given in Table 1 showed that the shape of the end of the can was already useful for closing cans containing relatively low pressures. It was also observed that the clamping of the double joining line with the joining line ring "D" resulted in a better pressure retention. Other tests were made using a wall angle for the mandrel and the mandrel bore surface inclined at almost 45 °: Table 2 shows the observed improvement: TABLE 2 Table 2 is based on observations made on can ends made of aluminum coated with polymeric film (ALULITE) to have a wall length for the mandrel of 5,029 millimeters (0.198") up to the inclination of 43 °. The vessel pressures achieved for samples J, K, L, of 4.89 bar (70.9 psig), 4.83 bar (70.0 psig) and 4.74 bar (68.7 psig), respectively, were greatly improved by holding the joint line In order to provide strength of the joint line without using a clamping ring, modified mandrels were used where the impulse inclination angle C ° was approximately 43 °, and the cylindrical surface 33 was generally +4 ° and -4 ° The results are shown in Table 3.

TABLE 3 ALL PRESSURES ARE IN BAR (PSIG) ALL CODES Diameter of Reform Pad :: 47.24 millimeters (1,860") (diameter 202). Unit depth h2 of 6.86 millimeters (0.270"); Depth of 2.39 mm (0.094") panel.

Table 3 shows the "0" Code made of Alulite of 0.25 millimeters, to give a Pressure Test Result of 6.62 bar (95 psi), indicating a suitable can end for pressurized beverages. Other mandrels with different floor lengths (inclination) were tested as shown in Table 4. TABLE 4 ALL PRESSURES ARE IN BAR (PSIG) CODE 7 = Alulite of 0.25 mm, Reform Cushion of 17.24 mm (1.860"), Depth h2 of 6.86 mm (0.270"), Panel of 2.38 mm (0.094"), Depth h4 = 2.29 mm (0.09"). 8 = Alulite of 0.23 mm, Reform Cushion of 17.24 mm (1.860"), Depth h2 of 7.11 mm (0.280"), Panel of 2.64 mm (0.104") Depth h4 = 2.54 mm (0.10"). 9 = Alulite of 0.23 mm, Reform Cushion of 17.24 mm (1.860"), Depth h2 of 7.37 mm (0.290"), Panel of 2.90 mm (0.114") Depth h4 = 2.79 mm (0.11"). Table 4 shows the results of another development for the configuration of the joining line forming mandrel, to bring closer the pressure resistance of the double ring supported lines and unsupported. Table 4 identifies the parameters for the length of a generally vertical cylindrical surface 33 on the forming mandrel of the joining line 30, and also identifies a positional relationship between the wall for the mandrel 24 of the end, and the connecting line double finished. From Figure 7, it will be understood that the forces generated by thermal processing or carbonated products are directed towards, and are resisted by, the stronger portions of the finished double joining line. Table 5 shows the results obtained from a typical union line mandrel designed to give a double bond line in accordance with the parameters and relationships identified in Table 4.

Typically: As shown in F8, the mandrel comprises a cylindrical floor of a length l1 typically of 1.4 millimeters (0.075"), and a truncoconical pulse surface 32 inclined at an angle Y °, typically of 43 °, with respect to to the cylindrical part with which it is joined by a radius R typically of 0.5 millimeters (0.020"). The "X" angle is typically 90 °.

TABLE 5 All the variables are made of Alulite, 10 cans per variable. The ends of the cans can be made economically from a thinner metal if the pressure retention requirements permit, because these ends of cans have a relatively small center panel in a more rigid ring. Figure 9 shows a can 12a, closed according to this invention, stacked on a similar can 12b shown sectioned, in such a way that the stacking of the upper can on the end of the lower can is achieved by a seat head 31a of the upper can fits inside the wall for the mandrel 24 of the end of the lower can, and the weight of the upper can rests on the double bond line 34 of the end of the lower can. The tolerance between the bottom of the upper can body and the end of the lower can can be used to accommodate pull ring features (not shown) at the end of the can, or promotional material, such as a rolled straw or indications. Using the experimental data presented above, a computer program was established to estimate the deformation resistance available to our ends of cans, when they were attached to containers containing a pressurized beverage. The last two entries in the Table refer to a can end of a known diameter 206, and an estimate of what we think the KRASKA Patent teaches.

TABLE 6 All experiments were modeled in a notional aluminum alloy with a yield strength of 310mpa with a thickness of 0.25 millimeters. The standard was also 310BUT; with a thickness of 0.275 millimeters.

Claims (10)

1. NOVELTY OF THE INVENTION
2. Having described the foregoing invention, it is considered as a novelty and, therefore, the content of the following is claimed as property:
3. CLAIMS 1. A can end comprising a peripheral cover hook (23), a wall for the mandrel (24) depending on the inner part of the cover hook, an outwardly concave annular reinforcing projection (25) that is extends radially inward from the wall for the mandrel, and a central panel (26) supported by an internal portion (27) of the reinforcing projection, characterized in that the wall for the mandrel (24) is inclined with respect to a perpendicular axis to the outside of the central panel (26) at an angle C between 30 ° and 60 °, and the radius in the concave cross-section of the reinforcing projection (25) is less than 0.75 mm. 2. A can end according to claim 1, characterized in that the angle of the wall for the mandrel (24) with respect to the perpendicular axis is between 40 ° and 60 °. 3. A can end according to claim 2, characterized in that the angle of the wall for the mandrel (24) with respect to the perpendicular axis is between 40 ° and 45 °.
4. 4. A can end according to claim 1, characterized in that an external wall of the reinforcing projection is inclined with respect to a line perpendicular to the central panel (26) of the can end, an angle between -15 ° and + 15 °, and the height h_ of the external wall is up to 2.5 mm.
5. 5. A can end according to claim 1, characterized in that the reinforcement projection has an internal portion parallel to an external portion joined by the concave radius.
6. 6. A can end according to claim as claimed in any of the preceding claims, characterized in that the ratio of the diameter of the central panel to the diameter of the peripheral corrugation is 80 percent or less.
7. 7. A can end according to claim 1, characterized in that it is made of a thermoplastic polymer film laminate and an aluminum foil alloy or tin plate, or electrochrome coated steel.
8. 8. A can end according to claim 7, characterized in that the laminate comprises a polyethylene terephthalate film on a sheet of aluminum-manganese alloy less than 0.010"(0.25 millimeters) thick. to form a double joining line between a can body (12) and a can end (22), in accordance with that claimed in any of the preceding claims, this method comprising the steps of: placing the undulation (23) of the end of the can on a flange (11) of a can body supported on a base plate (4), locate a mandrel (30) inside the wall for the mandrel (24) of the end of the can, this mandrel having a truncoconical impulse surface (32) of a substantially equal inclination B ° to that of the wall for the mandrel of the end of the can, and a substantially cylindrical surface portion (33) extending away from the surface impulse, cause relative movement between the can end assembly and the can body, and a roller of the first forming operation of the bond line (34), to form a joining line of the first operation, and then cause relative movement between the joining line of the first operation and a roller of the second operation (38), to terminate a double joining line, the wall for the mandrel (24) of the can becoming bent. , during these forming operations of the joining line, until making contact with the cylindrical portion (33) of the mandrel. A method according to claim 9, characterized in that the substantially cylindrical surface portion (33) of the mandrel is inclined at an angle between + 4 ° and -4 ° with respect to the longitudinal axis of the mandrel.