1. A method for cushioning the deceleration of a piston in an expandable chamber motor powered by a pneumatic fluid which comprises:
a) sensing a predetermined value in pressure of said pneumatic fluid on the downstream side of said piston in said expandable chamber motor, where said value indicates that said piston will reverse direction, and
b) using said predetermined value in pressure to pilot a main exhaust passage for allowing said pneumatic fluid to rapidly and substantially depressurize at, or just before, a bounce-back position, where said piston reverses direction, and
c) keeping sufficient pressure to pilot said main exhaust passage, until said pneumatic fluid on the downstream side has substantially depressurized,
whereby said piston of said expandable chamber motor is brought to a full stop with minimized deceleration forces, and minimized bounce back.
2. The method of claim 1 further including:
a. allowing said pneumatic fluid on said downstream side of said piston to initially escape through a preliminary exhaust passage, and
b. closing said preliminary exhaust passage for said pneumatic fluid after said piston reaches a predetermined position along the stroke of said piston, whereby said piston urges a rise in said pressure in remaining said pneumatic fluid.
3. The method of claim 2 further including changing an inactive volume of said downstream side whereby relocating said bounce-back position to the end of said stroke of said piston.
4. The method of claim 3 further including changing said predetermined stroke position, which blocks said pneumatic fluid from being further exhausted, whereby changing the start of the deceleration zone.
5. A means for unloading a pressurized fluid chamber comprising:
a. a pressure relief valve that opens at a predetermined pressure value, and
b. the output of said pressure relief valve pressurizes a pilot port of a second valve that exhausts said fluid chamber, and
c. a check valve and orifice that retains said output of said pressure relief valve in said pilot port of said second valve, until pressure in said pressurized fluid chamber reaches a lower, predetermined closing value,
whereby said chamber is unloaded from said predetermined value.
6. The article of claim 5 further including said predetermined closing value substantially approaches the pressure of an exhaust reservoir.
7. The article of claim 5 further including said means can be made as a replaceable cartridge.
8. The article of claim 5, wherein said second valve is a spring return valve.
9. The article of claim 5 further including:
a. said pressurized fluid chamber, is the downstream side of a piston in an expandable chamber motor powered by a pneumatic fluid, and
b. said predetermined value is a value that indicates that said piston will reverse direction.
10. The article of claim 9 further including:
a) a preliminary exhaust passage to allow a portion of said pneumatic fluid in said pressurized fluid chamber to escape from said pressurized fluid chamber, and
b) a means to close said preliminary exhaust passage after said piston has reached a predetermined position of said piston’s stroke, whereby said piston urges a rise in said pressure in remaining said pneumatic fluid.
11. The article of claim 10, further including a means to adjust an inactive volume of said downstream chamber, relocating the position where said piston will reverse direction to the end of stroke of said piston.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A fishing guide assembly for recovery of a skewed fish disposed askew in a larger tubular defined by a wall that is accessible by passage through a smaller tubular, comprising:
a fishing tool on a support to allow delivery of the fishing tool to the fish;
a guide mounted to a leading end of said fishing tool and selectively directly actuated by employment of potential energy stored or delivered to at least a portion of said guide not before passing, at least in part, through the smaller tubular whereupon said at least a portion of said guide moves toward a wall of the larger tubular to guide the skewed fish away from the wall and toward said fishing tool for grasping by said fishing tool and removal of the fish through said smaller tubular.
2. The assembly of claim 1, wherein:
said guide comprises fingers that are externally actuated to move toward the wall of the larger tubular.
3. The assembly of claim 1, wherein:
said guide comprises of spaced elongated fingers that move radially outwardly toward the wall of the larger tubular.
4. The assembly of claim 1, wherein:
said guide comprises of overlapping elongated fingers that move radially outwardly toward the wall of the larger tubular.
5. The assembly of claim 1, wherein:
said guide comprises a plurality of fingers that selectively extend to the wall of the larger tubular to guide the fish to the fishing tool as said fingers advance between the fish and the wall.
6. The assembly of claim 1, wherein:
said fishing tool comprises a spear or an overshot.
7. A fishing guide assembly for recovery of a skewed fish disposed askew in a larger tubular defined by a wall that is accessible by passage through a smaller tubular, comprising:
a fishing tool on a support to allow delivery of the fishing tool to the fish;
a guide mounted to a leading end of said fishing tool and selectively actuated after passing, at least in part, through the smaller tubular to move toward a wall of the larger tubular to guide the skewed fish away from the wall and toward said fishing tool for grasping by said fishing tool and removal of the fish through said smaller tubular;
said guide is at least in part made of a memory material that responds to a stimulus to move toward the wall of the larger tubular.
8. The assembly of claim 2, wherein:
said material comprises a shape memory alloy that is responsive to heat to move toward the wall of the larger tubular.
9. The assembly of claim 8, wherein:
said heat is applied through heaters mounted on said fingers.
10. The assembly of claim 9, wherein:
power for said heaters comes from a local or remote source.
11. The assembly of claim 10, wherein:
each of said fingers has a heater mounted thereon.
12. The assembly of claim 8, wherein:
said shape memory alloy is provided in the shape of elongated fingers;
said fingers forcibly retract to enter the smaller tubular with said fishing tool when the fish is engaged.
13. The assembly of claim 12, wherein:
said fingers are spaced apart or overlapping.
14. The assembly of claim 13, wherein:
said heat is applied through heaters mounted on said fingers.
15. The assembly of claim 14, wherein:
power for said heaters comes from a local or remote source.
16. The assembly of claim 15, wherein:
each of said fingers has a heater mounted thereon.
17. The assembly of claim 16, wherein:
said fishing tool comprises a spear or an overshot.
18. A fishing guide assembly for recovery of a skewed fish disposed askew in a larger tubular defined by a wall that is accessible by passage through a smaller tubular, comprising:
a fishing tool on a support to allow delivery of the fishing tool to the fish;
a guide mounted to a leading end of said fishing tool and selectively directly actuated by employment of potential energy stored or delivered to at least a portion of said guide after passing, at least in part, through the smaller tubular whereupon said at least a portion of said guide moves toward a wall of the larger tubular to guide the skewed fish away from the wall and toward said fishing tool for grasping by said fishing tool and removal of the fish through said smaller tubular;
said guide comprises fingers that store said potential energy that is retained by a retainer that is defeated to release said stored potential energy.
19. The assembly of claim 18, wherein:
said retainer comprises a band surrounding said fingers that is defeated mechanically, chemically, or thermally to release said stored potential energy.
20. A fishing guide assembly for recovery of a skewed fish disposed askew in a larger tubular defined by a wall that is accessible by passage through a smaller tubular, comprising:
a fishing tool on a support to allow delivery of the fishing tool to the fish;
a guide mounted to a leading end of said fishing tool and selectively actuated after passing, at least in part, through the smaller tubular to move toward a wall of the larger tubular to guide the skewed fish away from the wall and toward said fishing tool for grasping by said fishing tool and removal of the fish through said smaller tubular;
said guide comprises fingers that are externally actuated to move toward the wall of the larger tubular;
said fingers are extended with pistons that selectively extend radially from a hub having a passage therethrough through which the fish extends as said fishing tool is advanced toward the fish.