The present invention is related to plungers for use in sealant dispensing systems with collapsible sealant packaging.
Adhesives and sealants have conventionally been dispensed from disposable cartridges using pneumatic dispensing guns. Collapsible sealant packaging has been proposed, which can take up less space when transported and after sealant has been dispensed from the collapsible packaging. Variable dimensions of plungers and cartridge sleeves may change dispensing performance, including unwanted by-pass of a portion of the collapsible packaging around the plunger.
Disclosed herein is a plunger assembly for use in a sealant dispensing cartridge comprising: a plunger comprising a substantially cylindrical body and front end; and an anti-bypass retainer contacting the plunger comprising a front portion and an anti-bypass rim structured and arranged to expand radially outward when force is applied to the front portion.
Also disclosed herein is a sleeve and plunger assembly for use in a sealant dispensing cartridge comprising: a sleeve; a plunger comprising a substantially cylindrical body and front end; and an anti-bypass retainer contacting the plunger comprising a front portion and an anti-bypass rim structured and arranged to expand radially outward when force is applied to the front portion.
Further disclosed herein is a sealant dispensing system comprising: collapsible sealant packaging comprising a rigid front end including a front opening and a flexible sidewall extending rearwardly from the rigid front end; an inner sleeve structured and arranged to receive the flexible sidewall; and a plunger with an anti-bypass retainer inserted in the inner sleeve structured and arranged to slide forwardly along a longitudinal axis of the inner sleeve and press against a rear end of the flexible sidewall when air pressure is applied against a rear surface of the plunger.
A generally cylindrical inner sleeve 30 fits inside the outer retaining sleeve 12. The sleeve 30 includes a front end 31 and a back end 32 having a retaining flange 34. Collapsible sealant packaging, e.g., in the form of an adhesive or sealant-containing cartridge 40 having a flexible sidewall 45 is located within the sleeve 30 and front cap assembly 20. The collapsible sealant packaging 40 includes a domed rigid front end 41 with a front tip 42 and front opening 43. The rigid front end 41 has a rear rim 44. The collapsible sidewall 45 of the cartridge 40 has a rear end 46. An uncured adhesive or sealant may be filled into and subsequently dispensed from the cartridge 40.
A plunger 50 with an anti-bypass retainer 60 is located inside the sleeve 30. The tolerance or fit between the sleeve 30 and the plunger 50 and retainer 60, and the materials used to make the sleeve 30, plunger 50 and retainer 60, may be selected in order to allow the plunger to move in relation to the sleeve 30 under air pressure applied by a conventional pneumatic gun, while providing a sufficiently tight seal that prevents air from passing between the interface between the sleeve 30 and the plunger 50. As more fully described below, the plunger 50 includes a front anti-bypass retainer 60 that presses against the rear end 46 of the flexible sidewall 45 of the sealant packaging 40. The retainer 60 may radially expand in a manner that prevents the collapsible packaging 40 from by-passing around the retainer 60 and plunger 50. Expansion of the retainer 60 may prevent the flexible sidewall 45 of the collapsible packaging 40 from by-passing around the plunger 50, which could otherwise cause slow bleed of the sealant out of the front nozzle during the dispensing process.
The anti-bypass retainer 60 includes a front dome 61 with divided side sections and anti-bypass retainer rim 62 that may be biased radially outward, as more fully described below. The retainer 60 includes a central axial hole 64 and slots 65 through the sidewall of the front dome 61 and a rim 62. The shape of the front dome 61 may be selected to substantially conform with the hemispherical dome 27 of the front cap assembly 20.
Further details of the plunger 50 and anti-bypass retainer 60 are shown in
As shown in
During a sealant dispensing operation, the plunger 50 and retainer 60 are forced axially forward in the inner sleeve, typically by means of pneumatic pressure. Forward movement of the plunger 50 and retainer 60 forces the retainer 60 to press against the flexible sidewall 45 of the collapsible sealant packaging 40. The collapsible sealant packaging 40 and uncured sealant contained therein provide a reactive force against the retainer 60, which may cause the front dome 61 and retainer rim 62 to flex radially outward, and may cause the front portion of the front dome 61 to slide axially rearward on the cylindrical body 71 of the retainer attachment post 70. Prior to the anti-bypass retainer 60 coming into contact with the flexible sidewall 45 of the collapsible packaging 40, the outside diameter of the retainer rim 62 may be equal to or less than the outside diameter of the plunger 50. This allows for free movement up or down through the inner sleeve 30 for ease of initially loading the plunger 50 and retainer 60, and for reloading of a new collapsible package. For reloading of a new collapsible package, there is relative little resistance provided by the plunger 50 and retainer 60 as to require less force from the operator to slide the new collapsible package inside the inner sleeve 30. Pressure from the collapsible packaging 40 pushes down the anti-bypass retainer 60 near its front opening 64, thereby forcing the retainer rim 62 and lip 63 readially outward. The dome shaped geometry of the plunger 50 also provides support and guidance for the retainer 60 to move radially outwardly to the inner sleeve 30.
Upon deformation of the anti-bypass retainer 60, the lip 63 and rim 62 may press against the inner diameter of the inner sleeve 30 with force that is about 10 percent, or 20 percent, or 30 percent in comparison with a level of pneumatic pressure applied against the rear face of the plunger 50.
As further shown in
The vent notches 36 provide air flow paths from the interior of the inner sleeve 30 that contains the collapsible sidewall 45 of the sealant packaging 40 to thereby vent pressurized air that could otherwise remain trapped inside the inner sleeve 30. The vent holes 116 of the outer retaining sleeve 112 are in air flow communication with the vent notches 36 of the inner sleeve 30 to thereby facilitate the escape of pressurized air from the inner sleeve 30 to atmosphere. The vent notches 36 and vent holes 116 may be aligned with each other, for example, by providing features on the inner sleeve 30 and/or the outer retaining sleeve 112 that provide such alignment. Alternatively, the vent notches 36 and vent holes 116 may not necessarily be aligned with each other, in which case air can pass through the space between the outer surface of the inner sleeve 30 and the inner surface of the outer retaining sleeve 112 before being exhausted through the vent holes 116. Although vent notches 36 are shown in the inner sleeve in
Air venting from the interior volume of the inner sleeve 30 may provide for controlled collapse of the flexible sidewall 45 of the collapsible packaging 40 during sealant dispensing operations, for example, by ensuring that the rear end 46 of the collapsible sidewall is pushed forward by the plunger 50 and anti-bypass retainer 60 to dispense the sealant through the front opening 43 rather than allowing pressurized air to press directly against the sidewall 45. Such unwanted air pressure against the sidewall 45 can cause the sidewall 45 to constrict in the middle, thereby trapping a portion of the sealant and preventing its flow through the front opening 43. The air venting provided by the vent notches 46 may also reduce or prevent unwanted sealant discharge or drool that may otherwise occur after air pressure against the back side of the plunger 50 is removed at the end of a dispensing operation.
The retainers 12 and 112 may be made of any suitable rigid material such as metal, plastic and the like. For example, the retainers 12 and 112 may be made of steel or aluminum. A viewing slot (not shown) may optionally be provided through the retainer 12, 112, e.g., running parallel with the longitudinal axis of the retainer 12, 112. The front cap assembly may be made of any suitable material such as plastic or metal. For example, the front cap assembly may be made of a polymer such as nylon. The sleeve 30 and plunger 50 may be made of any suitable materials such as plastic, e.g., polyethylene, polyurethane, polypropylene or the like. The plastic sleeve 30 may be slightly resilient or flexible and may have lower thermal conductivity than the retainer 12, 112, i.e., to provide thermal insulation.
The flexible sidewall 45 of the cartridge 40 may be made of relatively thin sheets of laminated foil or any other suitable type of collapsible material. The domed rigid front end 41 may be made of relatively rigid materials such as plastic and the like. For example, the rigid front end 41 and front tip 42 may be made of a polymer such as polyethylene. The sealant contained in the cartridge 40 may be any suitable sealant or adhesive formulation known to those skilled in the art such as those used in the aerospace industry.
The retainer systems of the present invention may be used with standard adhesive and sealant guns known to those skilled in the art including, but not limited to, pneumatically driven guns sold under the designations Semco Model 250-A, Model 250-B and Model 350.
The front-loading sealant dispensing system 10 as shown in
It is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers such as those expressing values, amounts, percentages, ranges, sub-ranges and fractions may be read as if prefaced by the word “about,” even if the term does not expressly appear. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Where a closed- or open-ended numerical range is described herein, all numbers, values, amounts, percentages, sub-ranges and fractions within or encompassed by the numerical range are to be considered as being specifically included in and belonging to the original disclosure of this application as if these numbers, values, amounts, percentages, sub-ranges and fractions had been explicitly written out in their entirety.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in any of the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.
As used herein, unless indicated otherwise, a plural term can encompass its singular counterpart and vice versa, unless indicated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances.
As used herein, “including”, “containing” and like terms are understood in the context of this application to be synonymous with “comprising” and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, ingredients or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, ingredient or method step. As used herein, “consisting essentially of” is understood in the context of this application to include the specified elements, materials, ingredients or method steps “and those that do not materially affect the basic and novel characteristic(s)” of what is being described.
Whereas specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/090,991, filed Oct. 13, 2020, which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/054050 | 10/7/2021 | WO |
Number | Date | Country | |
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63090991 | Oct 2020 | US |