Passive Latch Mechanism for a Drilling Rig Mast

Abstract

An automatic mast section latching system is disclosed that provides rapid and safe connection of sequential mast sections without placing an employee in a lift to complete the task. A slot flange extends above each mast section for connecting to a pin section extending below a mast section above it. A first pin and a second pin extend perpendicularly from each pin flange. A slot is formed on the slot flange for receiving the first pin. A ramp is formed on the top of the slot flange. A seat is formed on the ramp for receiving the second pin.

1 . A drilling rig mast comprising:
 a first mast section;   a second mast section;   a slot flange extending beyond an end of the first mast section;   a pin flange extending beyond an end of the second mast section;   a first pin extending outward from the pin flange;   a second pin extending outward from the pin flange;   a slot formed on the slot flange, the slot configured to receive the first pin;   a ramp formed on an end of the slot flange;   a radial seat formed on the ramp, the seat configured to receive the second pin when the first pin is located in the slot; and,   the first mast section connectable to the second mast section by location of the first pin in the slot and location of the second pin in the seat.   
     
     
         2 . The drilling mast of  claim 1 , further comprising:
 the seat forming a radial relief on the ramp.   
     
     
         3 . The drilling mast of  claim 2 , further comprising:
 the seat being non-tangential to the ramp to form a ramp inflection between them.   
     
     
         4 . The drilling mast of  claim 2 , further comprising:
 a compression arc formed on the seat, beginning at the ramp inflection.   
     
     
         5 . The drilling mast of  claim 4 , further comprising:
 the compression arc being at least 45 degrees.   
     
     
         6 . The drilling mast of  claim 1 , further comprising:
 the slot having a slide and an edge, and a radial cup connecting the slide to the edge; and,   the distance from a center of the cup to a center of the seat being equal to the distance between the center of the first pin and the center of the second pin.   
     
     
         7 . The drilling mast of  claim 6 , further comprising:
 the radial cup being non-tangential to the edge of the slot to form a slide inflection between them.   
     
     
         8 . The drilling mast of  claim 7 , further comprising:
 a tension arc formed on the cup, beginning at the slide inflection.   
     
     
         9 . The drilling mast of  claim 8 , further comprising:
 the tension arc being at least 45 degrees.   
     
     
         10 . The drilling mast of  claim 4  further comprising:
 the cup being non-tangential to the edge. 
 
     
     
         11 . The drilling mast of  claim 2  further comprising:
 the ramp being inclined in the direction of the slot, at an angle of between 10 and 20 degrees. 
 
     
     
         12 . The drilling mast of  claim 3  further comprising:
 the slide being inclined in an amount slightly greater than that of the ramp. 
 
     
     
         13 . The drilling mast of  claim 1  further comprising:
 the second pin being laterally offset from the first pin by at least the amount by which the cup center is offset from the seat center. 
 
     
     
         14 . A drilling rig mast comprising:
 a first mast section having a front side and opposing rear side, and a top end and an opposing bottom end;   a second mast section having a front side and opposing rear side, and a top end and opposing bottom end;   a slot flange extending upward from the top end of the rear side of the first mast section;   a pin flange extending downward from the bottom end of the rear side of the second mast section;   a pin extending outward from the pin flange;   a slot formed on the slot flange, the slot configured to receive the first pin; and,   location of the pin in the slot aligns an opposing pair of pinned connections between the first and second mast sections on their front side.   
     
     
         15 . A method of connecting consecutive sections of a drilling mast, comprising:
 pivotally connecting a lower end of a first mast section to a drilling floor, the first mast section having a slot flange on an upper end;   providing a slot having a cup and a ramp having a seat on the slot flange;   inclining the first mast section into a position below a horizontal plane;   providing a second mast section having a pin flange on its lower end;   providing a first pin and a second pin on the pin flange;   moving the lower end of the second mast section towards the upper end of the first mast section until the second pin engages the ramp;   raising the inclination of the first mast section until the first pin moves into the slot cup;   raising the inclination of the first mast section until the second pin moves into the seat; and,   connecting a front side of the first and second mast sections together.   
     
     
         16 . A method of connecting consecutive sections of a drilling mast, comprising:
 pivotally connecting a lower end of a first mast section to a drilling floor;   inclining the first mast section into a position below a horizontal plane;   moving a lower end of a second mast section towards the upper end of the first mast section;   engaging a second pin on a pin flange on the lower end of the second mast section with a ramp on a slot flange on the upper end of the first mast section;   raising the inclination of the first mast section until a first pin on the pin flange is positioned in a cup on the slot flange;   raising the inclination of the first mast section until the second pin is positioned in a seat on the slot flange; and,   connecting a front side of the first and second mast sections together.