Cap assembly having inside seal
A seal and method of forming a seal for a resealable container includes a removable cap that is selectively received over a pour opening formed in a can body. A seal is adhered to the end wall of the cap and includes a continuous, first axial region extending outwardly from the inner surface of the cap. The seal first region is dimensioned for engagement with the opening in the container and sealing the container along an inner diameter thereof. Reduced on-torque/off-torque are required since the seal is formed on the inner diameter, and a down force is substantially reduced to assemble the cap to the container.
1. A resealable container assembly comprising:
a container that is either metal or glass and closed at a first end so as to be configured for holding an associated fluid at a preselected pressure therein, and having an opening at a second end, the opening having an inner, first diameter through which the associated fluid is introduced into and poured from the container, the container having thread portions adjacent the second end along an external surface thereof;
a metal cup-shaped cap having an end wall, and a perimeter sidewall extending from the end wall, wherein the cap includes roll on pilfer proof (ROPP) thread portions that are formed for selective twist-on/twist-off receipt relative to the thread portions on the container; and
a seal adhered to an inner surface of the end wall of the cap, the seal including a continuous first axial region extending outwardly from the cap inner surface a larger extent than a remainder of the seal, the first axial region of the seal having a radially outer, external surface dimensioned for sealing engagement with a smallest inner diameter of the container opening, such that the external surface of the first axial region seals the container along the smallest inner diameter of the container opening, whereby the seal formed between the first axial region and the smallest inner diameter of the container opening maintains the associated fluid within the container at pressure while holding the cap on the container with less than 100 pounds of down force during formation of the ROPP thread portions.
2. The container assembly of claim 1 wherein the container includes a curl at the second end to form the opening, the curl defining an apex portion of the container opening.
3. The container assembly of claim 2 wherein the seal includes a second, shoulder region adjacent an interface of the first axial region with the end wall of the cap, the shoulder region dimensioned for engagement along the apex portion.
4. The container assembly of claim 3 wherein the engagement of the second shoulder region along the apex portion control and drag forces generated when the cap is moved relative to the container rather than sealing the pressure of the associated fluid within the container, which is performed solely by the seal formed between the first axial region in the smallest inner diameter of the container opening.
5. The container assembly of claim 1 wherein the seal formed between the first axial region and the smallest inner diameter of the container opening maintains the associated fluid within the container at pressure when less than 70 pounds of down force is used during formation of the ROPP thread portions.
6. A resealable container assembly comprising:
a container that is either metal or glass and closed at a first end so as to be configured for holding an associated fluid at a preselected pressure therein, and having an opening at a second end, the opening having an inner, first diameter through which the associated fluid is introduced into and poured from the container, the container having thread portions adjacent the second end along an external surface thereof;
a metal cup-shaped cap having an end wall, and a perimeter sidewall extending from the end wall, wherein the cap includes circumferentially spaced lugs dimensioned for selective twist-on/twist-off receipt relative to the thread portions of the container; and
a seal adhered to an inner surface of the end wall of the cap, the seal including a continuous first axial region extending outwardly from the cap inner surface a larger extent than a remainder of the seal, the first axial region of the seal having a radially outer, external surface dimensioned for sealing engagement with a smallest inner diameter of the container opening such that the external surface of the first axial region seals the container along the smallest inner diameter of the container opening, whereby the seal formed between the first axial region and the smallest inner diameter of the container opening maintains the associated fluid within the container at pressure when the cap is twisted into threaded engagement with the container at a unitless, first numerical value equal to an on-torque maximum numerical value measured in inch-pounds and a second numerical value equal to a numerical diameter of the cap measured in millimeters, wherein the first numerical value less than one-half of the second numerical value.
7. The container assembly of claim 6 wherein the unitless, first numerical on-torque maximum value used when the cap is twisted into threaded engagement with the container is between 3 and is less than one-half the unitless, second numerical value.
8. The container assembly of claim 6 wherein the container includes a curl at the second end to form the portion, the curl defining an apex portion of the container opening, the seal includes a second, shoulder region disposed radially outward of an interface of the first axial region with the inner surface of the end wall of the cap, the shoulder region dimensioned for engagement along the apex portion of the container opening.
9. The container assembly of claim 8 , wherein the engagement of the second shoulder region along the apex portion controls drag forces generated when the cap is twisted relative to the container rather than sealing the pressure of the associated fluid within the container, which is preformed solely by the seal formed between the first axial region and the smallest diameter of the container opening.
10. The container assembly of claim 6 , wherein the seal formed between the first axial region and the smallest inner diameter of the container opening maintains the associated fluid within the container at pressure when the cap is twisted into threaded engagement with the container with a down force applied of less than 70 pounds.
11. A process of assembling a metal cap and one of a metal or glass container assembly so as to seal an associated fluid therein under pressure, the process comprising:
providing a metal cap;
providing a container having an opening with thread portions;
providing a seal on the metal cap that extends outwardly therefrom for sealing engagement with an innermost diameter of the opening, including (i) providing a continuous first axial region extending outwardly from the cap inner surface a larger extent than a remainder of the seal, and (ii) dimensioning the first axial region of the seal to have a radially outer, external surface dimensioned for sealing engagement with a smallest inner diameter of the container opening;
installing the cap on the container such that the sealing engagement is formed between the first axial region and the smallest inner diameter of the container opening, the sealing engagement configured to hold the associated fluid at a preselected pressure; and
forming roll on pilfer proof (ROPP) thread portions on the cap while the cap is held on the container with less than 100 pounds of down force during formation of the ROPP thread portions and the sealing engagement of the first axial region with the smallest inner diameter of the container opening maintains the associated fluid within the container at pressure during the formation of the ROPP thread portions.
12. The process of claim 11 further comprising providing a shoulder region of the seal disposed radially outward of an interface of the first axial region with the inner surface of the end wall of the cap, and dimensioning the shoulder region for engagement along an apex portion of the container opening and terminating adjacent the apex portion and radially inward of an outermost diameter of the second end of the container.
13. The process of claim 11 wherein the seal forming step includes dimensioning the seal to have an axial length that extends axially inward of the curl.
14. The process of claim 11 further comprising placing a dollop of seal material in a central region of an inner surface of the cap;
engaging the cap inner surface with a tool that forms a seal around a perimeter of the dollop of seal material; and
providing a desired profile of the seal material on the inner surface of the metal cap.
15. The process of claim 11 further comprising applying the cap to the container with less than 70 pounds of down force to seal the cap to the container while holding the associated fluid within the container under pressure.
16. The process of claim 11 further comprising including a second, shoulder region adjacent an interface of the first axial region with an end wall of the cap, the shoulder region dimensioned for engagement along an apex portion of the container opening, and generating drag forces when the cap is moved relative to the container rather than sealing the pressure of the associated fluid within the container, which is performed solely by the seal formed between the first axial region in the smallest inner diameter of the container opening.
17. A process of assembling a resealable metal cap and one of a metal or glass container assembly that seals an associated fluid therein under pressure comprising:
providing a metal cap having circumferentially spaced lugs;
providing a container having an opening with thread portions that cooperate with the circumferentially spaced lugs of the metal cap for selective twist-on/twist-off receipt of the metal cap relative to the thread portions on the container;
providing a seal on the metal cap that extends outwardly therefrom for sealing engagement with an innermost diameter of the opening, including (i) providing a continuous first axial region extending outwardly from the cap inner surface a larger extent than a remainder of the seal, and (ii) dimensioning the first axial region of the seal to have a radially outer, external surface dimensioned for sealing engagement with a smallest inner diameter of the container opening; and
installing the cap on the container such that the sealing engagement is formed between the first axial region and the smallest inner diameter of the container opening, the sealing engagement being configured to hold the associated fluid at a preselected pressure therein with an on-torque maximum value used when the cap is twisted into threaded engagement with the container at a value measured in inch-pounds less than one-half a diameter of the cap measured in millimeters.
18. The process of claim 17 further comprising forming a shoulder region of the seal disposed radially outward of an interface of the first axial region with the inner surface of the end wall of the cap, and dimensioning shoulder region for engagement along an apex portion of the container opening and terminating adjacent the apex portion and radially inward of an outermost diameter of the second end of the container.
19. The process of claim 17 further comprising twisting the cap on to the container with an on-torque maximum value measured at a value between 3 inch-pounds and less than one-half the diameter of the cap measured in millimeters.
20. The process of claim 17 further comprising applying the cap to the container with less than 70 pounds of down force to seal the cap to the container while holding the associated fluid within the container under pressure.
21. The process of claim 17 further comprising including a second, shoulder region adjacent an interface of the first axial region with an end wall of the cap, the shoulder region dimensioned for engagement along an apex portion of the container opening, and generating drag forces when the cap is moved relative to the container rather than sealing the pressure of the associated fluid within the container, which is performed solely by the seal formed between the first axial region in the smallest inner diameter of the container opening.