Air cannon

A prior art powered wrist pin knocker is imported with a new plunger that prevents wobbling. The new plunger responds to a return vacuum pressure. The improved plunger is symmetrical along a longitudinal axis. New embodiments include a new side mount valve head to reduce length, a remote air controller and a variable length cylinder for the cannon. The new valve head is a simplified valve head assembly that adapts to an end of the cannon mount or a side mount or a remote mount. Another embodiment provides a stand for a surface mount application. This embodiment can have an extended piston for loosening tail bearings down a long channel. A manual return embodiment can use a rod to manually return the plunger to the proximal end for another firing cycle.

FIELD OF INVENTION

The present invention relates to using compressed air to fire a cylindrical projectile (about a foot or more in length) down a tube so as to dislodge a wrist pin or similar pin stuck in a pivot point hole, especially in an oil pump.

BACKGROUND OF THE INVENTION

Oil pumping rigs such as disclosed in U.S. Pat. No. 6,655,224 (2003) to Ji et al. have a wrist pin-shown in FIG. 1 as prior art. These pins wear out and must periodically be replaced. Usually the crank arm is removed from the rig for this operation. Historically a twenty-pound sledge hammer is manually swung against the old stuck wrist pin.

Known in the art is a black powder cannon that may be used to unseat a wrist pin in place on the rig, which may present risks to the worker.

The closest prior art known is shown inFIGS. 2, 3, 4 and 6. An American International Manufacturing Corporation Wrist Pin Knocker is shown. The parts list follows below:

The swivel nut3is screwed onto an adapter that is screwed onto an end of the stuck wrist pin. The wrist pin knocker is ready when the piston P is set at the swivel nut end. Then the 100 to 125 PSI air hose is connected to the hose nipple12. Next a control handle6A (also used as a hammer) is set to the return position→to draw via suction the piston P to the valve guard8end. Next the handle is set to the neutral N position. Next the handle is quickly moved to the forward position←which causes the piston P to hit the stuck wrist pin. This operation is repeated until the wrist pin is loosened. The hammer6A can function as the handle H.

In practice with the one old unit on hand the return function did not work. Instead the swivel nut3had to be unscrewed, and the piston P had to be shoved with a stick up to the valve guard8end. The cylinder head4has a valving assembly that passes compressed air out the aspirator nozzle7via a narrow tube5inFIG. 2, thereby causing vacuum pressure at the valve guard8end for return of the piston P. Air holes in the outer filter retainer15in theory allow the piston P to be pulled by vacuum to the valve guard8end.

What is needed in the art is an improved piston design that enables the return function as noted above. Further needs are to protect the striking end of the piston P from destroying the inside of the cylinder1due to the wobbling of the heavy (twelve pound) steel piston in the aluminum cylinder. Another need is to protect the sliding collars on the piston from wear and tear.

Other needs may include shortening the length of the cannon as well as improving safety by moving the operator away from the cannon as well as providing an adjustable length cannon.

The present invention meets all these needs with an improved piston, a simpler valve assembly, a remote controller, a repositioned controller, and a modular cylindrical shaft.

SUMMARY OF THE INVENTION

The main aspect of the present invention is to provide an improved piston on a wrist pin knocker air cannon.

Another aspect of the present invention is to provide a simple valve assembly having minimal parts.

Another aspect of the present invention is to provide a remote control embodiment for a wrist pin knocker air cannon.

Another aspect of the present invention is to provide a modular length embodiment for a wrist pin knocker air cannon.

Another aspect of the present invention is to provide a shortened embodiment of the wrist pin knocker air cannon with a side mounted valve assembly.

Another aspect of the present invention is to provide a simple change kit to go from a side mount valve assembly to a remote control valve assembly.

Another aspect of the present invention is to provide a universal stand for deck mounting the air cannon.

Another aspect of the present invention is to provide an extension kit to drive a stuck shaft all the way out a long channel.

Before explaining the disclosed embodiments in detail, it is to be understood that the embodiments are not limited in application to the details of the particular arrangements shown, since other embodiments are possible. Also, the terminology used herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring next toFIGS. 2, 3, 4 and 6the original plunger hammer P shown had two problems. First it wobbled and chewed up the aluminum air cannon1shown inFIG. 6at the impact end60. The air exhaust ports61are shown which vent into the air exhaust muffler (labeled the outer filter retainer15inFIG. 1). A plunger hammer snap ring62is shown removed from the air cannon inFIG. 6. Dimension d13 is 25.25 inch. The control valve end is designated109.

The second problem was it did not return via vacuum pressure to the valve body109end when the handle H was moved to the return position. The device was designed to use the air pressure from inlet12to exhaust from the nozzle7, thereby creating a vacuum at the valve body109end. The original plunger hammer P weighed 12.54 lb. made of steel. Nylon bearings40,41were supposed to stop wobbling and reduce friction. They did not work. Nominal dimensions are d1=6.00 inch, d2=1.00 inch, d3=3.38 inch, d4=3.53 inch, d5=2.63 inch, d6=4.02 inch, d7=0.89 inch. Snap rings43,44hold the bearings40,41(nylon UHMW) in place.

It does not wobble, and it returns to the valve body end109under vacuum. Air exhaust relief ports63allow a certain amount of air to blow by the plunger hammer50. Bearings53,54(nylatron NSM) slide along the inside of air cannon1. InFIG. 5Arubber rings58,59have lips L1, L2that extend above the surface SUR1of the piston. Lip L1expands outbound as the plunger hammer50moves in the activate direction. Lip L2expands outbound when the plunger hammer moves in the retract direction. A space SP1shown inFIG. 5Dis created as a lip expands outbound. The end of the plunger hammer is labeled540. The plunger hammer50is symmetrical. InFIG. 5Ethe steel piston5050, has shoulders5005,5006narrowing the outside diameter about 0.25 inch to surface540. Groove5001houses bearing53. Groove5004houses bearing54. Groove5002houses o-ring58.

Referring nextFIGS. 7A, 7Ban air cannon1may need to be mounted to a base surface BS in order to strike an adjacent wrist pin or tail bearing (not shown). The air cannon1must have protective flanges700,701. A concave brace7000encases flange700via bolts8000. A concave brace7010encases flange701via bolts8000.

Stand820has feet721,722with crossbars900having a bolt901connection to feet721,722. Shims999are stacked to achieve a height and level for air cannon1. The floating bridges741have a concave indent for flanges700,701. Bolts8000secure the shims999at a desired height.

Referring next toFIGS. 8A-8Ia side mounted air cannon and valve assembly80shortens the longitudinal length d13 to about 25 inches. This is about six inches shorter than the prior art air cannon1shown inFIG. 2. The valve assembly is designated100. The aspirator is designated101. It has a compressed air inlet102. A pressurized air PI or vacuum air VAC outlet is designated103. This outlet103from the aspirator101is connected by hose669to hole670in the end cap671. Compressed air CA is fed by hose666to aspirator inlet102. Channel790connects the inlet102through the aspirator101. A rotatable shaft104is manually turned nominally by a handle6as shown inFIG. 2. The rotatable shaft104turns the rotatory plate105that has channels106,107,108,109. Channel106is connected to channel109via hole CH2. Channel107is connected to channel108via hole CH1. These channels align with aspirator ports1060,1070,1080,1090to provide three modes of operation.FIG. 8Cshows a null alignment between any channels or ports. The air inlet102dead ends at point NULL. This defines the neutral mode. A pin778enters the detent777to define the neutral position. Arrows CN show the compressed air in path.

FIG. 8Dshows the activate plunger mode. Channel106aligns with aspirator port1060, and channel109aligns with aspirator port1090. The compressed air is ported into the valve end109(seeFIG. 8G) thereby driving the plunger P down the air cannon1.FIG. 8Gshows the valve to barrel locking peg2001with swivel pin2003that locks the end cap671to the aspirator101, after the end cap671is screwed tight to the air cannon1. Bolts872secure the locking anchor2007end cap671.

FIGS. 8B and 8E and 8Hshow how the compressed air PI is jetted across a proximal end2021of a vortex tube2020, thereby creating a vacuum at the base VAC of the aspirator nozzle7. This vacuum is transmitted out the outlet103via hose669to hole670and retracts the plunger50back to the valve end109. An end plug2025holds the vortex tube2020in place. Nylon seals2040allow movement of the rotary plate without air leakage. A (nylon) bearing2041is held in place by a top cap2042.

Referring next toFIG. 9a remote control cannon90taps an air hose666from the air supply CA into the aspirator101via inlet102. The controller R100has all the same features as the embodiment shown inFIGS. 8A-8I. The outlet hose669supplies either the activate pressure or retract vacuum to hole670shown inFIG. 8G. Easy conversion from a side mount to a remote mount controller is done by releasing the swivel pin2003.

Referring next toFIG. 10A, 10Bthe cannon1is replaced with the valve end segment115that has a flange116. An extended cylinder117has a flange118mating with flange116. The distal end of extended cylinder117has a flange116D that mates with flange118D of distal extender121. Bolts1161and nuts1162hold all flanges together. For a short air cannon distal extender121can connect directly to valve end segment115.

Referring next toFIGS. 11A, 11Ba universal clamp1100is shown to grasp a wrist pin1101having damaged threads1102. The universal clamp1100threads into the air cannon1. Setting bolts1103are tightened around the damaged threads1102. The piston hits the head1104of the universal clamps1100, and the shock is transmitted to the damaged wrist pin1101, via the setting bolts1103.

Referring next toFIG. 12A, 12Ba wrist pin1200with usable threads1201is shown. A pin holder1202threads onto threads1201. The outer threads1203of pin holder1202thread into the air cannon1. A variety of pin holders are made with varying mating threads1204(and mating thread diameters) to accommodate many models of wrist pins in the field.

Referring next toFIGS. 13A, 13Ba piston extension kit1300is shown which is generally used in conjunction with the tail bearing pin removal stand shown inFIG. 7B. The cannon adapter1301threads into the air cannon1. The piston hits head1302. The distal end1303of the cannon adapter1301receives a first piston extender1304via a locking pin1305. The first piston extender1304is used to drive a stuck tail bearing its length dx down the channel. Then a second piston extender1306is affixed to the first piston extender1304via locking pin1307. Again the stuck tail bearing is driven down its channel another distance dx. Finally a third (or more as shown by piston extender FINAL) piston extender1308is affixed to the second piston extender via locking pin1309, and the stuck tail bearing is freed.

Referring next toFIG. 14a manual return air cannon8000uses the same compressed air CA. A simplified valve manifold1050has only an off position with the handle8020, or an activate position to fire the piston8030. The piston8030has a retrieval loop8031. After firing the user opens the end cap8032using the hinge8033. Then the user places a stick8035that has a hook8036to fish onto the loop8031and pull the piston8030back to the end cap8032. Then the user closes the end cap8032and locks it closed using lock8034. The valve manifold1050may optionally be remote as shown inFIG. 9.

Referring next toFIG. 15a manual return air cannon9000uses the same compressed air CA. A simplified valve manifold1050has only an off position with handle8020, or an activate position to fire the piston9030. A retrieval wire9031is attached to piston9030. A hole9003in the end cap9001permits the retrieval wire9031to slide back and forth with minimal air leakage. The end cap9001has a side entrance port9002for the control air. The hose6690connects to the side of the end cap9001. After firing the user pulls the retrieval wire9031to return the piston9030back to the end cap9001. The valve manifold1050may optionally be remote as shown inFIG. 9.

While a number of exemplifying features and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and subcombinations thereof. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.