US3503542A - Dispenser seal method and apparatus for forming the same - Google Patents

Description

March 31, 1970 Q A. J. UNGERER 3,503,542

DISPENSER SEAL, METHOD AND APPARATUS FOR FORMING THE SAME Filed April 13, 1967 INVENTOR. AARON J. UNGERER 7%07 may ATTORNEYS.

United States Patent 3,503,542 DISPENSER SEAL, METHOD AND APPARATUS FOR FORMING THE SAME Aaron J. Ungerer, Lakewood, Ohio, assignor to The Standard Products Company, Cleveland, Ohio, a corporation of Ohio Filed Apr. 13, 1967, Ser. No. 630,555 Int. Cl. B67d 5/42 US. Cl. 222386 1 Claim ABSTRACT OF THE DISCLOSURE A seal for a cartridge dispenser, including a slidable end closure and interposed between the end closure and the inner wall of the cartridge, a substantially vapor impermeable, thin, flexible sheet having a low bursting strength, in pressure contact with the end closure.

This invention relates to the art of packaging seals, and more particularly to an improved dispenser seal.

The present invention is particularly applicable to prepackaged cartridge dispensers for caulking-type materials, and it will be described with particular reference thereto; however, it will be appreciated that the invention has broader applications and may be used with other types of dispensers and different categories of materials.

Cartridge dispensers of the type having an integral nozzle and a slidable end closure are a common form of packaging for caulking-type materials. Such cartridge dispensers are used with open or split caulking guns having a trigger assembly which actuates a piston, operative against the slidable end closure. As the end closure is forced toward the nozzle end of the cartridge, the material contained Within the cartridge is extruded through the nozzle.

Some difiiculty has been experienced in using cartridge dispensers of the type described for packaging materials which are adversely affected by ambient atmosphere. Thus, for instance, certain synthetic polymeric resinous materials which are cured by air or moisture, have been found to have unsatisfactorily short shelf lives when packaged in cartridge dispensers of conventional design. This is attributed to the fact that the seal formed by the slidable end closure and the inner Wall of the cartridge is not sufiiciently tight to prevent ingress of moisture and air into the interior of the cartridge. Over an extended period of time, the penetration of air or moisture can eventually cure the entire mass of material within the cartridge, rendering it entirely useless. Even in the short term, the penetration of a small amount of air or moisture will cure the resinous material surrounding the slidable end closure, effectively welding it to the inner wall of the carfridge. Frequently, this localized bond is so strong that the application of pressure by the caulking gun piston will not break it. In some cases, this bond can be broken manually, with great difficulty. In other cases, the bond is so strong that it cannot be broken without destroying the cartridge.

Thus, the present invention is addressed to overcoming these difliculties, by providing a seal for cartridge dispensers, which has improved resistance to penetration by ambient atmosphere and can be broken readily notwithstanding a localized curing or hardening of the contents of the dispenser in the vicinity of the seal. This is accomplished by interposing between the end closure and the inner wall of the cartridge, with at least partial envelopment of the former, a thin, flexible sheet which is substantially impermeable to the component, such as moisture, of ambient atmosphere having a curing or hardening effect on the contents of the cartridge, and which thin sheet has a low bursting strength. For purposes of this disclosure the term substantially impermeable as applied for instance, to a thin, flexible sheet which is substantially impermeable to moisture, is intended to embrace any material which transmits moisture at a significantly lower rate than does air. The term bursting strength refers to the pressure required to rupture the thin, flexible sheet, and for purposes of this disclosure a low bursting strength is one which is less than the pressure exerted against the thin, flexible sheet by the end closure when the latter is acted upon by the caulking gun piston.

The seal of the present invention, when intact, functions to maintain the end closure out of contact with the contents of the cartridge. Any bonding which takes place by virtue of curing or hardening of the contents of the cartridge, is between the thin, flexible sheet and inner wall of the cartridge. Due to the low bursting strength of the thin, flexible sheet, the seal can be broken readily upon actuation of the caulking gun piston.

Also when intact, the improved seal, having high resistanee to penetration by ambient atmosphere due to the presence of the thin, flexible sheet, retards the rate of curing or hardening of the contents of the cartridge, there by increasing the shelf life of the prepackaged product.

In accordance with one aspect of the present invention, there is provided in a dispenser for viscous material, comprising a cartridge having an interior wall, and an end closure slidably movable therealong upon application of an external force to said end closure; the improvement comprising sealing means for the end closure in the form of a substantially vapor impermeable, thin, flexible sheet, in pressure contact with the end closure and interposed between the end closure and the interior wall of the cartridge, the sheet having a bursting strength Which is less than the pressure exerted thereagainst by the end closure upon application of an external force.

It is therefore an object of the invention to provide a dispenser seal of improved construction.

Another object of the invention is to provide a dispenser seal which overcomes certain disadvantages of prior art seals.

Another object of the invention is to provide a dispenser seal which provides improved resistance to penetration by ambient atmosphere, can be readily broken, notwithstanding localized hardening or curing of the contents of the dispenser in the vicinity of the seal, and assists in expelling air from the cartridge.

These and other objects and advantages will become apparent from the following detailed description of a preferred embodiment of the invention when read in connection with the accompanying drawings, in which:

FIGURE 1, is a schematic, pictorial view with parts cut away, showing a preferred embodiment of dispenser seal;

FIGURE 2, is a schematic, pictorial view showing a preferred embodiment of apparatus for forming a dispenser seal in accordance with the present invention;

FIGURE 3, is a schematic, elevation view, with parts in section and parts omitted, showing the apparatus in one phase of its operating cycle;

FIGURE 4, is a schematic, elevation view, with parts in section and parts omitted, showing the apparatus in another phase .of its operating cycle; and

FIGURE 5, is a schematic, elevation view, with parts in section and parts omitted, showing the apparatus in yet another phase of its operating cycle.

Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the same, FIGURE 1 shows a dispenser comprising cartridge 10, having front closure 12 formed with nozzle 14, and end closure 16. In the preferred form of the invention illustrated, end closure 16 is a cup-shaped element or plug, however it will be appreciated that other configurations of an end closure may also be used. Cartridge 10 may be lined with a substantially vapor impermeable barrier layer which may take a variety of forms, such as a plastic film or thin metal foil, but in the preferred embodiment illustrated, is a thin facing of aluminum designated in the drawing as 18.

Interposed between end closure 16 and the interior wall of cartridge 10, is a substantially vapor impermeable, thin, flexible sheet 20, in pressure contact with the outside bottom of cup-shaped end closure 16, and enveloping and extending slightly beyond the side walls of the end closure. If desired, the edges of the blank from which flexible sheet 20 is formed may be pinked, though this is not essential.

Flexible sheet 20 may be formed from a variety of materials, such as thin plastic or metal films, but in the preferred embodiment shown, is formed of aluminum foil having a thickness within the range of 1 to mils. Whatever the nature of flexible sheet 20, it should have a relatively low bursting strength, i.e., it should rupture readily under the application of a fairly low pressure. More particularly, the bursting strength of flexible sheet 20 should be less than the pressure exerted against it by end closure 16, when the latter is forced forward by the caulking gun piston when dispensing material from the cartridge.

In accordance with the preferred form of the invention, flexible sheet 20 is partially enveloped around end closure 16 prior to the insertion of the end closure in the open end of cartridge 10. This causes the formation of crimps 22 in flexible Sheet 20. When end closure 16 is inserted in the open end of cartridge and pushed forward, air behind material 24 is expelled through crimps 22. End closure 16 is advanced until it contacts material 24 and then is maintained in pressure contact with the material for a time and with a force suflicient to cause the material to exude between flexible sheet 20 and the adjacent inner wall of cartridge 10. In this manner, the expulsion of air from the interior of the cartridge is completed. Where material 24 is susceptible to curing or hardening upon exposure to ambient atmosphere, the small amounts of the material filling crimps 22 will cause a bond to be formed between portions of flexible sheet 20 and the adjacent portions of the inner wall of cartridge 10. Since flexible sheet 20 extends across the bottom of end closure 16 and envelops and even extends beyond the side walls of the end closure, it will be understood that no bond is formed between the end closure itself and the cured or hardened material 24. Thus, end closure 16 is free to move when pressure is exerted against it by the piston of a cartridge gun. Due to the low bursting strength of flexible sheet 20, upon the application of such force to end closure 16, sheet 20 will burst generally along the peripheral edge of the outside bottom of end closure 16. While intact however, the flexible sheet 20 forms a very satisfactory seal against the entry of ambient atmosphere into the cartridge. This substantially increases the shelf life of the material contained in the cartridge. In addition, as described above, the seal is readily broken, so that the cartridge, even after having been stored for substantial periods of time, can be placed into use without encountering undue difliculty in breaking the seal.

Referring to FIGURES 2 and 3, there is shown a preferred embodiment of apparatus useful for forming a seal in accordance with the present invention. For purposes of discussing the apparatus, it may be divided into four major subassem'blies, namely, a frame generally designated A, cartridge support means designated generally as B, plug or end closure supply means designated generally as C, and means supplying a blank of thin, flexible sheet material designated generally as D.

Cartridge support means B comprises a lower collar 26 operative to support front closure 12 of cartridge 10 against axial movement, and upper collar 28 operative to support cartridge 10 against lateral movement. As best seen in FIGURE 2, collars 26, 28 are supported between vertical members forming a part of frame A.

End closure supply means C is shown in the form of ram means comprising an air or hydraulic cylinder 30, piston 32 having head 34. To support end closure 16, head 34 may be provided with a variety of means, but in the preferred embodiment shown, this is accomplished by frictional engagement of the end closure with frustoconical portion 36.

As best seen in FIGURE 3, piston 32 moves along a path from an elevated position away from cartridge 10, to a lowered position toward cartridge 10. When in an elevated position, an end closure is supplied to portion 36 either manually or by automatic means not shown and forming no part of the present invention, whereupon the piston is lowered.

Means supplying a blank of flexible sheet material comprises a stationary drawing die 38 secured to frame A, and having on its upper surface a backing plate 40. Positioned above backing plate 40 is a movable assembly comprising a guide sleeve 42, cutting blade 44, and hold down means, which in the preferred embodiment takes the form of resilient annulus 46. As shown in FIGURE 3, cutting blade 44 is provided with mounting edge 48 securing it to guide sleeve 42, and a substantially continuous cutting edge 50.

Movement of the assembly comprising guide sleeve 42, cutting blade 44, and resilient annulus 46, as accomplished by cylinder 52 mounted on frame A, and piston 54 which is connected to upper camming blocks 56 slidable in guides 58. Guide sleeve 42 is provided on its upper surface with lower camming blocks 60, which are held in engagement with upper camming blocks 56, by one suitable means such as springs, not shown. Extension of piston 54 out of cylinder 52, causes upper camming blocks 56 to urge lower camming blocks 60, guide sleeve 42, cutting blade 44, and resilient annulus 46 to move downwardly. Movement of piston 54 into cylinder 52 causes a withdrawal of upper camming blocks 56, permitting the aforementioned movable assembly to move upwardly.

A length of flexible material 62 is fed to the machine from feed roll 64, and trim 66, left after blanking of the flexible material, is withdrawn from the machine on take up roll 68 driven by motor 70. Indexing of length of flexible material 62 is accomplished by any suitable means synchronizing the operation of motor 70 with the movement of piston 54, which in the preferred embodiment illustrated takes the form of circuit 72 including relay switch 74.

The operation of the appartus is as follows. With pistons 32, 54 withdrawn into their respective cylinders 30, 52, an end closure 16 is placed on frusto-conical portion 36 of piston head 34. A cartridge 10 previously filled with material 24 is placed on cartridge support means B, nozzle down, as shown in FIGURE 3. The operating cycle of the appartus is started by pressing start button 76. This causes hydraulic fluid or air from a source not shown to flow into the dead end of cylinder 52, causing piston 54 to move out of the cylinder. In this manner, upper camming blocks 56 urge lower camming blocks 60, guide sleeve 42, cutting blade 44 and resilient annulus 46 downwardly. As best seen in FIGURE 4, this causes resilient annulus 46 and backing plate 40 to engage opposite surfaces of trim portions of flexible material 62, While cutting blade 44 severs a blank of flexible sheet 20. With the various parts in this position, piston 32 is caused to lower by the introduction of hydraulic fluid into the dead end of cylinder 30. Thus, piston 32 carrying end closure 16 is lowered through guide sleeve 42, cutting blade 44, and into engagement with the blank of flexible sheet 20. Further lowering of piston 32 causes end closure 16 to drag the blank of flexible sheet material ahead of it, and through drawing die 38, which causes the blank to envelop itself around the outer walls of end closure 16. As best shown in FIGURE 5, a further lowering of piston 32 causes end closure 16 partially enveloped in the blank of flexible material 20 enters the open end of cartridge 16.

The downward movement of piston 32 continues until end closure 16 enveloped in the blank of flexible sheet 20 is brought into pressure engagement with the material 24 contained in cartridge 10. This pressure engagement is maintained for a few seconds, to permit material 24 to exude upwardly to fill the spaces between flexible sheet 20 and the inner wall of cylinder 52, including the crimps in flexible sheet 20.

During this time, piston 54 holds the movable assembly comprising guide sleeve 42, cutting blade 44, and resilient annulus 46 in its downward position, and this assembly remains in its lowered position until piston 32 is raised above guide sleeve 42. Upon this happening, piston 54 returns into cylinder 52, permitting the aforementioned movable assembly to move upwardly and disengage the trim portions of the length of flexible material 62. This movement of piston 54 causes a signal to be transmitted through circuit 72 to relay switch 74, which in turn energizes motor 70 to operate for a period sufficient to wind up enough of trim 66 to provide an unblanked portion of length of flexible material 62 at the work station of the apparatus. The sealed cartridge is then removed from cartridge support means B, and the apparatus is ready to repeat its cycle.

The present invention has been described in conjunction with certain specific embodiments; however, it is to be appreciated that various changes may be made in the illustrated embodiments without departing from the intended scope and spirit of the present invention as defined 35 in the appended claim.

Having thus described my invention, I claim:

1. In a dispenser for viscous material comprising a cartridge having an interior wall, and an end closure having a periphery disposed in close proximity to said interior wall and a surface facing the inside of said cartridge, said end closure being slidably movable along said interior wall upon application of an external force to said end closure, the improvement comprising, said end closure being cup-shaped with said surface corresponding to the outside bottom of the cup and said periphery corresponding to the side wall of the cup, sealing means for said end closure in the form of a substantially vapor impermeable, thin, flexible sheet extending across and in pressure contact with said surface of said end closure and interposed between said sidewall of said end closure and the interior wall of said cartridge, the portion of said flexible sheet covering the side wall of said end closure having crimps filled with a material bonding said portion to the interior wall of said cartridge, said sheet having a bursting strength which is less than the pressure exerted thereagainst by said end closure upon application of said external force.

References Cited UNITED STATES PATENTS 2,478,078 8/1949 Battenfield 222327 2,646,906 7/ 1953 Jones et al 222327 X 2,649,999 8/1953 Burch 222--327 X 2,887,253 5/1959 Biedenstein 222-327 2,941,699 6/1960 Schmidt et al 222327 3,130,872 4/1964 Myers et al 222327 X ROBERT B. REEVES, Primary Examiner F. R. HANDREN, Assistant Examiner U.S. C1. X.R. 222--80, 327

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