Subsurface chills to improve railcar knuckle formation

• US 9,308,578 B2
• Filed: 12/21/2011
• Issued: 04/12/2016
• Est. Priority Date: 12/21/2011
• Status: Active Grant

• Current Assignee: Bedloe Industries LLC
• Original Assignee: Bedloe Industries LLC
• Inventors: Smerecky, Jerry R., Nibouar, F. Andrew, Brooks, Noland, Salamasick, Nick
• Primary Examiner(s): Yoon, Kevin E
• Assistant Examiner(s): Yuen, Jacky
• Application Number:
  US13/333,035
• Publication Number:
  US 20130160961A1
• Time in Patent Office: 1,574 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B22C 13/02 equipped with templates, e.g. for sweeping operation
• CPC Class Codes: B22C 7/04 Pattern plates
• CPC Class Codes: B22C 9/02 Sand moulds or like moulds for shaped castings
• CPC Class Codes: B22C 9/062 Mechanisms for locking or opening moulds
• CPC Class Codes: B22C 9/064 Locating means for cores
• CPC Class Codes: B22C 9/065 Cooling or heating equipment for moulds
• CPC Class Codes: B22C 9/08 Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
• CPC Class Codes: B22C 9/082 Sprues, pouring cups
• CPC Class Codes: B22C 9/088 Feeder heads
• CPC Class Codes: B22C 9/10 Cores; Manufacture or installation of cores breaker cores B22C9/084
• CPC Class Codes: B22C 9/101 Permanent cores
• CPC Class Codes: B22C 9/103 Multipart cores
• CPC Class Codes: B22C 9/22 Moulds for peculiarly-shaped castings
• CPC Class Codes: B22D 15/00 Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
• CPC Class Codes: B22D 15/04 Machines or apparatus for chill casting B22D15/005, B22D15/02 take precedence
• CPC Class Codes: B22D 25/02 by its peculiarity of shape; of works of art cylinders, pistons B22D15/02
• CPC Class Codes: B22D 35/04 into moulds, e.g. base plates, runners
• CPC Class Codes: B61G 3/04 with coupling head having a guard arm on one side and a knuckle with angularly-disposed nose and tail portions pivoted to the other side thereof, the nose of the knuckle being the coupling part, and means to lock the knuckle in coupling position, e.g. "A.A.R." or "Janney" type
• CPC Class Codes: B61G 7/00 Details or accessories

Abstract

A method for manufacturing a railcar coupler knuckle includes, before casting, positioning an external chill within a cope mold portion and a drag mold portion offset from and adjacent internal walls of a pulling face and a throat of the cope and drag mold portions, thus producing a casting with reduced micro-shrinkage in at least the throat, a high-stress section of the casting. Use of subsurface chills produces an improved surface with fewer inclusions when compared to an equivalent surface produced in a process without use of a subsurface chill. The external chill may be a cone chill of a larger size to improve cooling and solidification at and below the surface. The external chill may also be a cylindrical and/or oblong chill with a tapered design that may correspond to the internal walls of the cope and drag mold portions between the pulling face and the throat.

Claims

1. An assembly for casting a light steel railcar coupler knuckle, comprising:

a cope mold portion, the cope portion having internal walls defining at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion;

a drag mold portion, the drag mold portion having internal walls defining at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion;

at least one riser preceding and engaged with at least one ingate in the front face portion;

at least one internal core placed to define within the coupler knuckle a finger cavity, a pivot pin cavity forming a C-10 pin hole, and a kidney cavity;

a first subsurface external chill positioned within the cope mold portion, the first chill positioned between the front face portion and the tail portion of the cope and drag mold portions and adjacent to the throat portion and the C-10 pin hole, the first chill offset at least ⅛

″

from and adjacent the internal walls of the pulling face and the throat of the cope mold portion, where a wall of sand exists between the first chill and the internal walls of the coupler knuckle mold cavity;

a second subsurface external chill positioned within the drag mold portion, the second chill positioned between the front face portion and the tail portion of the cope and drag mold portions and adjacent to the throat portion and the C-10 pin hole, the second chill offset at least ⅛

″

from and adjacent the internal walls of the pulling face and the throat of the drag mold portion, where a wall of sand exists between the first chill and the internal walls of the coupler knuckle mold cavity;

wherein the first and second chills are positioned within each of the cope and drag mold portions such that the chills contact each other along a centerline of the casting after the cope and drag mold portions are closed prior to casting;

wherein a coupler knuckle is formable of metal from the cope and drag mold portions that include the chills, the coupler knuckle including an improved surface with reduced subsurface micro-shrinkage at a location of at least the throat of the coupler knuckle as compared to an equivalent surface cast in a process using a surface chill; and

wherein the improved surface extends substantially between the pulling face and lock shelf of the coupler knuckle.

2. The assembly of claim 1, wherein the at least one internal core comprises two internal cores, a first internal core placed to define within the coupler knuckle a finger cavity and a second internal core placed to define within the coupler knuckle a pivot pin cavity and a kidney cavity.

3. The assembly of claim 2, wherein the first and second chills are each cone shaped.

4. The assembly of claim 3, wherein the first and second chills are each truncated cones including dimensions of a major diameter of more than 2.0″

, a minor diameter of more than 1.50″ and

a height of more than 1.85″

.

5. The assembly of claim 4, wherein the first and second chills each comprise a volume of at least ten cubic inches.

6. The assembly of claim 5, where the first and second chills each comprise a maximum cross section of about four square inches.

7. The assembly of claim 6, wherein the first and second chills each comprise a mass of at least 3 pounds.

8. An assembly for creating a mold for casting a light steel railcar coupler knuckle, comprising:

a first pattern plate;

a second pattern plate;

a first pattern half attachable to the first pattern plate with which to form a cope mold portion, the first pattern half having exterior walls defining in the cope mold portion at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion;

a second pattern half attachable to the second pattern plate with which to form a drag mold portion, the second pattern half having exterior walls defining in the drag mold portion at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion;

at least one riser preceding and engaged with at least one ingate in the front face portion;

a first subsurface external chill releasably attached to the first pattern plate positioned between the front face portion and the tail portion of the first pattern plate and adjacent to the throat portion and a C-10 pin hole, the first chill offset at least ⅛

″

from and adjacent a throat region of respective pattern halves, wherein the first chill is configured to remain trapped within the cope mold portion when the first pattern half is removed from the cope mold portion;

a second subsurface external chill releasably attached to the second pattern plate positioned between the front face portion and the tail portion of the second pattern plate and adjacent to the throat portion and the C-10 pin hole, the second chill offset at least ⅛

″

from and adjacent a throat region of respective pattern halves, wherein the second chill is configured to remain trapped within the drag mold portion when the second pattern half is removed from the drag mold portion; and

wherein the first and second chills are attached to the first and second pattern plates such that the chills contact each other along a centerline of the casting after the cope and drag mold portions are closed prior to casting.

9. The assembly of claim 8, wherein the first chill is releasably attached to the first pattern plate with a plurality of vertical pins and wherein the second chill is releasably attached to the second pattern plate with a plurality of vertical pins.

10. The assembly of claim 9, wherein the first and second chills each include a larger cross sectional area on a side that is mounted to the pattern plates than the cross sectional area taken at any other height.

11. The assembly of claim 10, wherein the first and second chills are cone shaped.

12. The assembly of claim 11, wherein the first and second chills are truncated cones including dimensions of a major diameter of more than 2.0″

, a minor diameter of more than 1.50″ and

a height of more than 1.85″

.

13. The assembly of claim 12, wherein the first and second chills each comprise a volume of at least ten cubic inches.

14. The assembly of claim 13, wherein the first and second chills each comprise a maximum cross section of about four square inches.

15. The assembly of claim 14, wherein the first and second chills each comprise a mass of at least 3 pounds.

16. The assembly of claim 8, wherein the chills are comprised of one or more materials selected from the group consisting of:

cast steel, cast gray iron, graphite, silicon carbide and a combination thereof.