Method for applying a precision amount of sealant to exposed fasteners

• US 4,971,745 A
• Filed: 06/30/1986
• Issued: 11/20/1990
• Est. Priority Date: 10/15/1984
• Status: Expired due to Term

• Current Assignee: Vought Aircraft Industries, Inc. (Triumph Group, Inc.)
• Original Assignee: LTV Aerospace & Defense Co. (LTV Corp.)
• Inventors: Mize, Jay B., Ferenc, Robert R.
• Primary Examiner(s): Lorin, Hubert C.
• Application Number:
  US06/881,520
• Time in Patent Office: 1,604 Days
• Field of Search: 264/279, 264/271.1, 264/263, 264/272.11, 264/40.5, 264/268, 264/276
• US Class Current: 264/263
• CPC Class Codes: B05C 17/00503 Details of the outlet element B05C17/00523 takes precedence; nozzles for deformable tubular containers B65D35/38
• CPC Class Codes: B29C 45/14336 Coating a portion of the article, e.g. the edge of the article B29C45/14573 and B29C45/14598 take precedence
• CPC Class Codes: B29K 2021/006 Thermosetting elastomers
• CPC Class Codes: B29K 2075/02 Polyureas
• CPC Class Codes: B29L 2031/3076 Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: F16B 33/004 Sealing; Insulation by means of washers F16B43/001

Abstract

A method for applying a uniform sealant coating over the portion of a fastener exposed above a panel includes applying a sealant retaining shell over the exposed portion of the fastener to define a closed volume between the shell, fastener and panel. The shell has an aperture, removed from the mouth of the shell, for receiving sealant therethrough. An injection nozzle receiving structure for receiving a sealant injector nozzle therein is provided adjacent and substantially aligned with the aperture. Sealant is injected into the shell through the injection nozzle receiving structure and through the aperture therein to fill the area between the fastener and the shell. A pressure is selected for injecting the sealant such that injection is stopped when the shell is filled. The sealant is allowed to cure and the retaining shell is removed.

Claims

1. A method of applying a sealant over an object comprising:

(a) applying a sealant retaining shell, having an interior cavity with a mouth thereto, with the mouth of the cavity engaging the object;

(b) applying a force on the shell to engage the mouth of the shell against the object;

(c) injecting an amount of sealant into the interior cavity of the sealant retaining shell under a pressure sufficient to cause said sealant to fill the space between the object and the interior cavity of the shell and insufficient, when said space is filled with said sealant, to overcome said applied force to step (b) and force said sealant to flow between the mouth of the shell and the object, thereby arresting the flow of sealant into said cavity; and

(d) allowing the sealant to cure.

2. The method according to claim 1 further comprising:

removing the shell after the sealant has cured.

3. The method according to claim 1 wherein the shell has a pre-determined interior configuration and volume.

4. A method of applying a sealant around the portion of a fastener exposed above a panel to which the fastener is attached comprising:

applying a sealant retaining shell over the exposed portion of the fastener to define a closed volume between the shell, fastener and panel;

applying a pressure on the shell to engage the shell against the panel during injection of the sealant;

injecting an amount of sealant into the interior cavity of the sealant retaining shell at a pressure such that sealant fills the space between the object and the interior cavity of the shell but is arrested when the space is filled thereby preventing the flow of fluid between the mouth of the shell and the object; and

allowing the sealant to cure.

5. The method of claim 4 wherein said pressure is about 35 psi.

6. The method according to claim 4 further comprising:

removing the shell after the sealant has cured.

7. The method according to claim 4 wherein said injecting comprises:

injecting an amount of sealant into the shell substantially equal to the difference in volume of the interior cavity of the shell and the volume of the exposed portion of the fastener.

8. A method of applying a sealant to cover the portion of a fastener exposed above a panel to which the fastener is attached and the point of engagement of the fastener with the panel comprising:

(a) applying a sealant retaining shell over the exposed portion of the fastener and into contact with the panel to define a closed cavity between the shell and the fastener and panel;

(b) applying a force on the shell to engage the shell against the panel during injection of the sealant;

(c) injecting an amount of sealant into the interior cavity of the sealant retaining shell under a pressure sufficient to cause said sealant to fill the space between the object and the interior cavity of the shell and insufficient, when said space is filled with said sealant, to overcome said applied force of step (b) and force said sealant to flow between the mouth of the shell and the object, thereby arresting the flow of sealant into said cavity; and

(d) allowing the sealant to cure.

9. The method according to claim 8 wherein said pressure is about 35 psi.

10. The method according to claim 8 further comprising:

removing the shell after the sealant has cured.

11. The method according to claim 8 wherein the shell has a pre-determined interior configuration and volume.

12. The method according to claim 8 further comprising:

centering the shell over the exposed portion of the fastener prior to the curing of the sealant to provide a uniform sealant coat around the fastener and at the point of engagement of the fastener with the panel.

13. A method of applying a sealant over an object comprising:

applying a sealant retaining shell, having an interior cavity with a mouth thereto, with the mouth of the cavity engaging the object;

injecting an amount of sealant into the interior cavity of the sealant retaining shell through single port in the head of the shell opposite the mouth of the shell with the mouth of the shell engaging the object such that the space between the object and the interior cavity is filled with sealant;

allowing the sealant to cure; and

further comprising

(a) applying a force on the shell to engage the mouth of the shell against the object, and

(b) injecting said sealant into the shell under a pressure sufficient to fill said space but insufficient when said space is filled with said sealant to overcome said applied force on the shell and force said sealant to flow between the mouth of the shell and the object, thereby arresting the flow of sealant into said cavity.

14. A method of applying a sealant over an object comprising:

applying a sealant retaining shell having an interior cavity with a mouth thereto, with the mouth of the cavity engaging the object, the shell having a port in the head thereof with an injection nozzle receiving connection communicating with the port,

engaging an injection nozzle in the nozzle receiving connection;

injecting an amount of sealant through the port into the interior cavity of the sealant retaining shell with the shell engaging the object such the space between the object and the interior cavity is filled with sealant;

allowing the sealant to cure;

removing the shell after the sealant has cured by engaging the nozzle receiving connection; and

further comprising

(a) applying a force on the shell to engage the mouth of the shell against the object, and

(b) injecting said sealant into the shell under a pressure sufficient to fill said space but insufficient when said space is filled with said sealant to overcome said applied force on the shell and force said sealant to flow between the mouth of the shell and the object, thereby arresting the flow of sealant into said cavity.

15. The method according to claim 14 wherein the shell has a pre-determined interior configuration and volume.

16. The method of applying a sealant over an object comprising:

(a) applying a sealant-retaining shell having an interior cavity with a mouth of the cavity engaging the object, said shell having a nozzle-receiving connection defined by a cup formed in the exterior surface of said shell in the head thereof opposite the mouth of said shell, said cup having an injection port at the base thereof opening into the interior of said shell;

(b) engaging the tip of an injection nozzle into said cup and into communication with said port to permit the injection of sealant from said nozzle and through said port into the interior of said shell;

(c) injecting an amount of sealant through said nozzle and said port into the interior cavity of the sealant retaining shell with the shell engaging the object such that the space between the object and the interior cavity is filled with sealant;

(d) allowing the sealant to cure;

(e) removing the shell after the sealant has cured; and

further comprising engaging the tip of said injection nozzle into said cup under an applied force on said shell to engage the mouth of the shell against the object and injecting said sealant into the shell under a pressure sufficient to fill said interior cavity but insufficient when said interior cavity is filled with said sealant to overcome the applied force imposed by the tip of said nozzle on the shell and force said sealant to flow between the mouth of the shell and the object, thereby arresting the flow of sealant into said cavity.