Method and system for manufacturing railcar coupler locks

Abstract

A casting assembly for manufacturing a lock of a railcar coupler includes drag and cope portions of a first mold that defines exterior surfaces of the lock, wherein the first mold comprises a first molding material. The casting assembly also includes a second mold formed of a second molding material. The second mold defines a cavity with an interior surface that substantially complements an exterior surface of the first mold. A down sprue is formed in the second mold. A gating system is formed in the second mold that and is in fluid communication with the down sprue. An in-gate is formed in the second mold and is in fluid communication with the gating system and the first mold.

We claim: 
     
         1 . A method of manufacturing a lock of a railcar coupler, where the lock includes a rear guide portion at a first end, a leg portion in a middle section, and a slot at a second end, where a knuckle side surface of the lock near the first end defines a knuckle locking face and a coupler side surface of the lock that is opposite to the knuckle side surface defines a coupler locking face, the method comprising the steps of:
 forming a pattern of a lock in drag and cope portions of a first mold that comprises a first molding material to thereby form a cavity that defines exterior surfaces of the lock;   forming, in a second mold that comprises a second molding material, a cavity with an interior surface that substantially complements an exterior surface of the first mold;   forming, in the second mold, a down sprue, a gating system in fluid communication with the down sprue, a riser in fluid communication with the gating system, and an in-gate in fluid communication with the gating system and the first mold;   curing t he first mold and the second mold;   assembling the drag and cope portions of the first mold;   inserting the first mold into the second mold;   assembling the drag and cope portions of the second mold; and   pouring a molten material into the down sprue of the second mold, wherein the molten material subsequently flows into the first mold to thereby form the lock.   
     
     
         2 . The method according to  claim 1 , further comprising inserting the first mold into the cavity of the second mold. 
     
     
         3 . The method according to  claim 1 , wherein the first mold is a shell mold that includes an in-gate, and wherein during formation of the first mold uncured first molding material is removed from the first mold via a vent opening defined in a side of at least one of the drag and cope portions of the first mold to thereby reveal a venting cavity in the at least one portion, wherein the venting cavity is not connected to the cavity that defines the exterior surfaces of the lock. 
     
     
         4 . The method according to  claim 1 , wherein outside walls of the first mold are tapered. 
     
     
         5 . The method according to  claim 1 , wherein a parting line of the first mold that separates the cope portion from the drag portion follows a non-linear contour of the lock. 
     
     
         6 . The method according to  claim 1 , wherein the first molding material is a mixture of silica sand and a thermosetting phenolic resin. 
     
     
         7 . The method according to  claim 6 , wherein the second molding material is an air-set material. 
     
     
         8 . The method according to  claim 7 , wherein the second molding material comprises a first layer of mechanically separated sand that forms an outer portion of the mold, and a second layer of mechanically and thermally separated sand that forms an interior of the second mold that comes in contact with the first mold. 
     
     
         9 . The method according to  claim 1 , wherein the first molding material and the second molding material are a same material. 
     
     
         10 . The method according to  claim 1 , wherein immediately subsequent to removal of the lock from the first mold, a tolerance of a distance between the resulting knuckle locking face and the resulting coupler locking face of the resulting lock is less than or equal to about ±0.010 inches. 
     
     
         11 . The method according to  claim 1 , wherein at least one of the cope portion and the drag portion of the first mold defines a protrusion that forms the slot. 
     
     
         12 . The method according to  claim 1 , wherein the interior of the drag portion of the second mold is configured to receive at least two shell molds and to distribute the molten material to each of the at least two shell molds. 
     
     
         13 . The method according to  claim 1 , wherein the in-gate to the lock that is formed during casting is configured to be broken off. 
     
     
         14 . The method according to  claim 13 , wherein a diameter of the in-gate is less than 2 inches. 
     
     
         15 . The method according to  claim 13 , wherein the in-gate to the lock is located on a top of the first end of the lock. 
     
     
         16 . A method of manufacturing a lock of a railcar coupler, where the lock includes a rear guide portion at a first end, a leg portion in a middle section, and a slot at a second end, where a knuckle side surface of the lock near the first end defines a knuckle locking face and a coupler side surface of the lock that is opposite to the knuckle side surface defines a coupler locking face, the method comprising the steps of:
 forming a pattern of a lock in drag and cope portions of a first mold that comprises a first molding material to thereby form a cavity that defines exterior surfaces of the lock, wherein the cope portion defines a first opening configured to vent gases;   forming, in a second mold that comprises a second molding material, a cavity with an interior surface that substantially complements an exterior surface of the first mold;   forming, in the cope portion of the second mold, a first opening configured to vent the gases vented from the first opening in the cope portion of the first mold;   forming, in the second mold, a down sprue, a gating system in fluid communicating with the down sprue, and an in-gate in fluid communication with the gating system and the first mold;   curing the first mold and the second mold;   assembling the drag and cope portions of the first mold;   inserting the first mold into the second mold;   assembling the drag and cope portions of the second mold; and   pouring a molten material into the down sprue of the second mold, wherein the molten material subsequently flows into the first mold, via the gating system and in-gate, to thereby form the lock, wherein gases in the first mold are forced out by the molten material through the first opening in the cope portion of the first mold and subsequently through the first opening in the cope portion of the second mold.   
     
     
         17 . The method according to  claim 16 , wherein the cope portion of the first mold defines a second opening configured to vent gas, wherein the first opening in the cope portion of the first mold is positioned in proximity to the first end of the lock and the second opening in the cope portion of the first mold is positioned in proximity to the second end of the lock. 
     
     
         18 . The method according to  claim 17 , wherein the first opening is positioned at a location of the lock that is closest to a top surface of the cope portion of the drag mold. 
     
     
         19 . The method according to  claim 16 , wherein the cope portion of the second mold defines a second opening configured to vent the gases vented from the second opening in the cope portion of the first mold. 
     
     
         20 . The method according to  claim 16 , wherein the cope portion of the second mold defines a recess around the first opening in the cope portion of the second mold, and a width of the recess is about 1 in and a length of the recess is about 2 in. 
     
     
         21 . The method according to  claim 20 , wherein a depth of the recess is greater than about 0.125 in. 
     
     
         22 . The method according to  claim 16 , wherein the cope portion of the first mold defines a venting cavity positioned substantially adjacent to a region of the cope portion that forms the leg portion of the lock, wherein the venting cavity does not receive molten material during casting and is configured to vent gas via an opening formed in a side of the cope portion of the first mold out through a side opening formed in the second mold. 
     
     
         23 . The method according to  claim 16 , wherein immediately subsequent to removal of the lock from the first mold, a tolerance of a distance between the upper locking face and the lower locking face of the lock is less than or equal to about ±0.020 inches. 
     
     
         24 . A method of manufacturing a lock of a railcar coupler, where the lock includes a rear guide portion at a first end, a leg portion in a middle section, and a knuckle side that defines a slot at a second end, where a knuckle side surface of the lock near the first end defines a knuckle locking face and a coupler side surface of the lock that is opposite to the knuckle side surface defines a coupler locking face, the method comprising the steps of:
 forming patterns for at least two locks in drag and cope portions of a mold that comprises an air-set molding material to thereby form cavities that define exterior surfaces of the at least two locks;   forming, in the air-set molding material, a down sprue, a gating system in fluid communication with the down sprue, and at least two in-gates, each in fluid communication with the gating system and one of the at least two cavities;   curing the air-set molding material;   assembling the drag and cope portions of the mold; and   pouring the molten material into the down sprue of the cured air-set molding material, wherein the molten material subsequently flows through the gating system and into the cavities to thereby form the at least two locks.   
     
     
         25 . A casting assembly for manufacturing a lock of a railcar coupler, where the lock includes a rear guide portion at a first end, a leg portion in a middle section, and a slot at a second end, where a knuckle side surface of the lock near the first end defines a knuckle locking face and a coupler side surface of the lock that is opposite to the knuckle side surface defines a coupler locking face, the casting assembly comprises:
 drag and cope portions of a first mold that defines exterior surfaces of the lock, wherein the first mold comprises a first molding material;   a second mold formed of a second molding material, the second mold defines a cavity with an interior surface that substantially complements an exterior surface of the first mold   a down sprue formed in the second mold;   a gating system formed in the second mold that is in fluid communication with the down sprue;   an in-gate formed in the second mold that is in fluid communication with the gating system and the first mold.   
     
     
         26 . The casting assembly according to  claim 25 , wherein the first mold is a shell mold. 
     
     
         27 . The casting assembly according to  claim 25 , wherein a parting line of the first mold that separates the cope portion from the drag portion follows a non-linear contour of the lock. 
     
     
         28 . The casting assembly according to  claim 25 , wherein the first molding material is a mixture of silica sand covered and a thermosetting phenolic resin. 
     
     
         29 . The casting assembly according to  claim 27 , wherein the second molding material is an air-set material. 
     
     
         30 . The casting assembly according to  claim 25 , wherein the first molding material and the second molding material are a same material. 
     
     
         31 . The casting assembly according to  claim 25 , wherein at least one of the cope portion and the drag portion of the first mold defines a protrusion that forms the slot. 
     
     
         32 . The casting assembly according to  claim 25 , wherein the interior of the drag portion of the second mold is configured to receive at least two shell molds and to distribute the molten material to each of the at least two shell molds. 
     
     
         33 . The casting assembly according to  claim 25 , wherein the in-gate to the lock that is formed during casting is configured to be broken off. 
     
     
         34 . The casting assembly according to  claim 33 , wherein a diameter of the in-gate is less than about 2 inches. 
     
     
         35 . The method according to  claim 33 , wherein the in-gate to the lock is located on a top of the first end. 
     
     
         36 . A method of manufacturing a lock of a railcar coupler, where the lock includes a rear guide portion at a first end, a leg portion in a middle section, and a slot at a second end, where a knuckle side surface of the lock near the first end defines a knuckle locking face and a coupler side surface of the lock that is opposite to the knuckle side surface defines a coupler locking face, the method comprising the steps of:
 forming a pattern of a lock in drag and cope portions of a first mold that comprises a first molding material to thereby form a cavity that defines exterior surfaces of the lock;   forming, in a second mold that comprises a second molding material, a cavity with an interior surface that substantially complements an exterior surface of the first mold; and   forming, in the second mold, a down sprue, a gating system in fluid communication with the down sprue, a riser in fluid communication with the gating system, and an in-gate in fluid communication with the gating system and the first mold.