US2577479A - Safety device for polish rod mountings of deep well pumps - Google Patents

Description

Dec. 4, 1951 G. E. OWEN ET AL SAFETY DEVICE FOR POLISH ROD MOUNTINGS OF DEEP WELL PUMPS w mp r; W33 mfi f 5 H J v M r. A E F m 7 Wmww E y K G! -0 M W 5 Filed May 24, 1948 Patented Dec. 4, 1951 SAFETY DEVICE FOR POLISH RODMOUN '11- 'INGS OF DEEP WELL PUMPS George E. Owen, Downey, and Harris LBrendt, Long Beach, Calif.

Application May 24, 1948, Serial, No. 28,886

7 Claims.

This invention relates to safety controls, and more particularly to safety control devices especially adapted for use in connection with deep well pumps.

An important object of the invention is to provide safety means which will cut off the power employed in pumping deep wells in the event that the sucker rods which operate the pump should break or in the event that cable lengths from which the sucker rods are suspended should become unduly weakened or break.

As is well understood, deep wells of the oil well type are pumped by the reciprocation of long pump rods, commonly known as sucker rods, which depend in the pump tubing and carry at their lower ends pistons reciprocating in the pump barrels at thebottoms of the wells. The upper ends of these sucker rods are commonly suspended from cross headsor carrier bars which are in turn supported on .thelower ends of short cable lengths and actuatedbythe common walking beams which arerocked. upon appropriate mountings by devices which commonly are internal combustion engines or ele"- trio motors. and on occasion the suspending cables fray or break. Under such circumstances the power mechanism and the walking beainof such a well tend to run wild and frequently produce serious damage.

It is,therefore, a general object of this invention to provide safety means which will prevent the power mechanism from running wild and will avoid all damage incident to thedevelopment of such condition.

Another object is to produce a safety mechanism which is positive, efficient, relatively inexpensive to manufacture, and very easy to install.

Other objects and various features of the invention will become apparent to those skilled in this art upon reference to the following specification and accompanying drawing wherein one embodiment of the invention is illustrated.

In the drawing:

Fig. 1 is a side elevation illustrating the equipment employed commonly at the top of a pumping well, the invention hereof being illustrated in operative relationship with respect to such mechanism;

Fig. 2 is an elevational view showing astructure as seen from the right of Fig. 1;

Fig. 3 is principally a large scale top plan view of the structure of this invention, as indicated by the line 3-3 of Fig. 2, associated parts being Frequently, the suckerrods part,

prime mover.

.wise.

shown in cross section, and portions being broken away to facilitate disclosure;

Fig. fl is a fragmentary end view on an enlarged scale as indicated by the line 4l of Fig. 3;

Fig.5 is a front elevation of the structure of Fig. 3, being shown onthe same enlarged scale as in Fig. 3;

Fig. 6 is a fragmentary detail showing a desirable structural feature omitted from Fig. 3 to facilitate the disclosure; and

Fig. '7 is a perspective view on a reduced-scale, a, possible variation being shown.

Having reference toFig. l of the drawing, a conventional walking beam i8 is shown as being mounted through the medium of a pivot shaft ll upon theupper end of asupport l2 of conventional construction. The walking beam :tfi-is conventionally rocked by the usual pitman it ,pivotally connected with the-outer end of a rotating arm i5 actuated through mechanism in a gear case 16 from an engine ll or similar A conventional counterbalance l8 connected with the arm, [5 is also illustrated.

The oppositeend of the walking beam is shownas being equipped with a usual arcuate structure 20, .commonlyknown as a horsehead, presenting an outer, curved working surface upon which two short supporting oables-22 bear, their upper ends being commonly integrally joined and mounted on the upper end of the curved surface of the horseheadZG as by fixing to asaddle123. The walking beam l0, through the horsehead 26 andthe short cables 22, serves to reciprocate the usual polish rod 24 which is the topjoint of the usualsucker rod assembly .of'a deep'well pump 25, this reciprocation being effected through the. medium of .a cross head 28 commonly known in the oil industry as a carrierbar and carryinga clamp- 2'! of any preferred form bound to the polish rod 24. The lower ends of the cables 22 are fixed in the outer ends of. the cross heads 26 as indicated at 28.

The safety device of this invention is generally indicatedat' 3B and is principally shown in Figs. 3 and 5. Its purpose is to cut off power to the engine I! in the event that the sucker rod should break or part at any point, or the cables 22 pull loose from their mountings at23 or 28, or. break, or become unduly weakened by fraying or other- The safety device 30- operates to retain-a control device-3| under normal operatingconditions and to release the control device 3i in the event of the breaking or weakening just indicated. The control device 3! is carried on the end similar of a line 32 which leads to an appropriate junction box 33 or the like from which an electric conduit 34 leads to a magneto on the engine l'I. According to one form, the control device 3| may be a mercury switch which is open when the device 3! is in the upright position seen in Fig. 1, and is closed to ground the magneto if the control device 31 is dropped and becomes inverted. Or, the control device 3| might be a weight which when dropped will act through the line 32 to jerk a switch mechanism in the junction box 33 and open the circuit if an electric motor re places the engine 11.

Referring especially to Fig. 3, the safety device 38 comprises, as its principal constituents in the form shown, two opposing arms 35 clamped to the cables 22, two aligned, oppositely operating, expansible coil springs 36 adapted to be connected to the polish rod 24 at their inner ends and having bearing heads 38 at their outer ends, bearing seats 45 secured at the outer ends of the arms 35 and receiving the bearing heads 38, and a latch mechanism 41 adapted to carry the control device 3! and attached to the ends of the arms 35 adjacent the seats 48.

The seats lli are of any appropriate cupped or formation, such as the trough-like members shown which are provided at their bottoms with stops 58a (Fig. to limit downward movement of the heads 38. As illustrated, the latch mechanism 4| comprises a pin 42 attached to an adjacent end of a linkage 43, such as a chain section 43a, the other end of the linkage 53 being attached to the outer end of one of the arms 35 as presently to be described.

Another part of the latch mechanism 4| as illustrated is in the form of a cylindrical block 44 which receives the pin 42 in a bore disposed at its axis. The block 44 is carried on an adjacent end of a bracket attached to the outer end of the other arm 35 through the medium of an upstanding leg i5a.

Each arm 35 is clamped to its respective cable 22 by any appropriate means, thatshown comprising a U-shape block 46 providing spaced jaws between which the. cable is received as shown and a U-bolt 41 of conventional construction extending through appropriate passages in the U-shape block 46 and through openings in the respective arm 35, the ends of the U-bo1t 31 receiving anchor nuts 48 which bind the block to the cable 22 and thereby secure the respective end of the arm 35 to its cable 22. The outer end of each arm 35 is provided with an appropriate ear 50 mounted upon a flange 5| preferably integral with the respective end of the respective arm 35. One of the ears 50 receives the upper end of the upstanding leg 45a which is appropriately secured in place in any preferred manner, as by a set screw 52 and ,upper and lower nuts 53 which may be bound against the under and upper sides of the respective ear 55. Such means serve to anchor the bracket 45 in any vertically and horizontally adjusted position such as that illustrated. The free end of the bracket 45 carries the cylindrical block 55 through the medium of such means as a screw 54. It will be noted that the cylindrical block 44 is provided with an overhanging extension Ma spaced from the body of the block 44 by a slot 55 which is directed downward, as indicated in Fig. 5, when the parts are in their operative relationship as seen in Fig. 3. The slot '55 is adapted to receive an eye 56 carried upon the upper'end of the control device 3|, such .eye

55 being supported upon the inner end of the pin 52 when in the operative relationship indicated in Fig. 3. When the pin 42 is in such operative position its eye-supporting extremity bears against the inner face of the overhanging extension Ma, being received in a countersunk seat therefor, if preferred. Desirably, the pin 52 is positively retained in such operative position as by means of a U-spring 51 (Fig. 4) en gaging in appropriate notches or in a peripheral groove in the pin 12, the spring El being mounted in the outer end of the cylindrical block 55 as by means of a screw 53.

The end of the linkage l3 opposite from the latch mechanism e: is attached to the outer end of the respective arm 35 through the medium of a depending shank 83 whose upper end is secured to the respective ear 58 as by means of nuts ti and whose lower end is secured as by means of nuts 62 to an adjacent end of a rigid link 33 connected by a turn buckle 55 to a threaded link 65 or the like fixed to the adjacent end of the chain section 43a.

The inner or opposing ends of the expansible coil springs 36 are provided with mounting means so that they may be properly positioned by being mounted upon the upper end of the a retaining and tensioning nut Ti bearing againstthe adjacent spring end and cooperating with a lock nut it. 'Thus, proper tension is readily placed upon the spring 35 by the nut ii and retained by the lock nut 78. With the mounting shown in Fig. 3, it is desirable that the outer ends of the springs 35 be welded to the bearing heads 38 as indicated at 19, but a preferable construction may be that shown in Fig. 6 where a sleeve 88 is disposed between each spring 35 and its threaded shank 36. In this form, each bearing head 38 may be provided with a stud 82 over which the respective end of the sleeve fits, or the corresponding end otherwise secured to the bearing head as preferred. The sleeves 85 thus properly guide the outer ends of their springs 35.

As to the retainer i2 shown in Fig. '7, which is adapted to be employed instead of the clamp 10 of Figs. 3 and 5, the two threaded shanks 16 carrying the springs 38 are respectively attached to two spaced bars 85 which in turn carry opposed jaws 85 which are generally semi-cylindrical to engage around the polish rod 24% and are retained in such position by contracting coil springs 88 attached to the opposed ends of the bars 85. Thus, the curved jaws 86 are frictionally held by the springs 88 in engagement with the walls of the polish rod 25. Preferably, the upper ends of the jaws 86 are tapered outward as illustrated so that, should the clamp 21' on the cross head 25 fail to hold the polish rod 24, any type of stop shoulder carried at the upper end of the polish rod may passtherethrough without damaging the safety device 38. Such collar or shoulder 95 may, of course, then be caught upon any safety retainer carried by the cross head 26 or upon the top of the well pump, or elsewhere as preferred.

aeratin- Operation 3 w l be parent; f m the oreg in c.- scription, when the weight of the suckerrodsand thepump parts suspended thereby in the bottom of the. well is imposed upon the. cables 22 by being secured to the cross. head 26. through the medium of the clamp 21, such cables 22 are placed under a heavy strain tending to maintain them against any flexure. The arms 35, are then secured upon the cables 22 through the medium or" the clamps 46, 41 and the clamp 10, or the retainer '12, is positioned upon the upper portion of; the sucker rod 24, and the expansible coil; springs 36 are directed So that the bearing heads 3 8. are positioned in the bearing seats. 40 on the enter ends of the arms, 35. The tensioning nuts 11 are. thenturned down against the inner ends. of the respective springs 36 so as to place sufficient. tension thereon to cause the arms 35' to be forced apart should any large proportion of the weight on the sucker rods be released as by breakage, or should a sufiicient number of strands. of either or the cables 22 break to render the respective cable dangerousand thereby enable it tobe twisted by reason of the pressure exerted by the; springs. 36,.

The turnbuckle 64 is then adjusted so that substantially all slack is taken from the chain section 43a. whenthe pin 42 is inserted into the bore of the cylindrical block 44 of the latch mechanism 4|. 'I heeye 55 upon he upper end of the control device 3| is then introduced into the vertically disposed slot 55 in the cylinder block 44, and the pin 42 is passed through the eye 58 and into the operative position indicated'in Fig,

3, The U-spring 51 on the outer end of the block 44 serves, to retain the pin positively in such operative position. Under these conditions the control device 3] is suspended as seen in Fig. l,

Theline 32 which connects the control device 31. with the junction box 33 on the walking beam support I2 is sufficiently long. to provide for the usual reciprocating movement of the cross head 2.6.as it. is actuated by the horsehead'. Should enough of the strands of one eithe cables 22 'become broken to dangerously weaken the cable, such weakening will enable. the tension in the sp ingsiifi to twist that cable 22 by forcing th e. outerend ofthe respective arm outward; away from the, polish rod 24 and the other arm 35;

This movement may be aidedby a natural u ntwistingtendency oi the cable when some oi the strands break.

When such movement becomes sufficient to be ameasure. of a dangerous situation, the pin 42 ispulled from the slot and the controldevice 3] drops by reason of release of theeye Sit-on its upp erend. If the device 3i contains a mercury switch, the circuit to the magneto of the engine I! is grounded by reason of the closing of, said switch, or, if the device 3| is a weight andan electric motor is used, the circuit is brokenby reason of the actuation of a switch in the junction box 33 under influence of the weight. Thus, the engine or motor is stoppedand operation of the walking beam iii-ceases. Should the suckerrod or the polish rod z t-break, a similar result takes place because of the fact that re moval-oi the load from the cables 22 permitsthe arms 35, to be forced-apart by the springs 36 thereby dislodging the pin 42 from'its position in the cylindrical block 44,

It'is, therefore, apparent that the safety device herein disclosed readilyadaptsitself to-installation on a pump-reciprocating mechanism of: the. described character and will automatically function to stop themotor upon failure to. a pre:; determined degree of the sucker rod orits sup-. porting means. Since itis mounted atthe most sensitive point, the engine or motoris shut. off: instantly. upon any failure, and without any speed-up to actuate the device or running out of control. Also, the device performs shock absorbing functions. upon the cables to minimize, ordinary twisting and give them longer life.

Variations. of the generic invention herein. dis,- closed. are intended to be protected insofar as they fallv within the scope oi the claims.

We. claimv as our invention:

1. Ina safetyv combination: a weighted'device; spaced, twisted strand cables supporting saidweighted device; plural cable engaging, meansv respectively secured to said: cables; arm means extending respectively from said cable engaging;

' means in spaced relation; plural tension means mounted on said weighted device, and respectively engaging extending portions of the respective arm means, and maintained in normal tension by weight stresses on said cables when the; cables are in normal condition and acting to twistsaid-cables into distorted condition under other.- conditions, said tension mean being opposing spring means having mountings positioning them on. said weighted device and on said extending portions. of said arm means, said spring means serving to produce relative distortion. of said cables in the event of breakage of strands of said cables; relatively movable controlling means. operatively connected with said arm means and tension means for actuation upon relative cable distortion; and a control device carried by said relatively movable controlling means for control of av power. mechanism operating said weighted device, said control. device being energizable through movement of said relatively movable V controlling means upon development of said relae tivecable distortion.

2, A safety device for use in oil :Wellsin which a. polish rod is attached at its lower end toa string of sucker rods extending downwardly into,

the well and actuating a pump and attached at. its upperend to a cross head which is suspended from a walking beam by two sucker rodsupporting cables, the walking beam being reciprocated between limits by a prime mover, com-- prising in combination with said above enumeratedqparts: two arms, onev clamped to one of said cablessand' the other clamped to the otherv of said cables and both disposed in a plane to which the polish rod is perpendicular; an expane sible assembly having one end seated on the free end of one of said arms and its other end seated onthe free end of the other oi said arms, said expansible assembly having expansion spring means so placed as to tend to force said ends-of said expansible assembly apart and thus rotate each of said arms about its cable and force the free ends of said arms apart; and means by which the separation of the free end of said arm stops the operation of the prime mover.-

3. A safety device for use in oil wells in which apolish rod i attached at its lower end to. a string-of sucker.- rods extending downwardly into the-Welland actuating a pump and attached at its upper end to a cross head which is suspended from a walking beam by two sucker rod supporting: cables, thewalking beam being reciprocated between-limits by aprime mover, comprising in combination with said above enumerated parts:

76 7 two arms,.one clamped to. one-of said: cables and the other clamped to the other of said cables and both disposed in aplane to which the polish rod is perpendicular; an expansible assembly having one' end seated on the free end of one of said arms and its other end seated on the free end of the other of said arms, said expansible assembly having expansion Spring means so placed as to tend to force said ends of said expansible assembly apart and thus rotate each of said arms about its cable and force the free ends of said arms apart; a latch mechanism comprising a primary connecting member having a first end attached to the free end of one of said arms, a secondary connecting member having a first end attached to the free end of the other of said arms, and a connecting assembly detachably connecting the second ends of said primary member to the second end of said secondary member in such a manner that said second ends are disconnected when the free ends of said arms are moved apart; and means by which the disconnection of said second ends stops the prime mover.

4. A safety device for use in oil well in which a polish rod is attached at its lower end to a string of sucker rods extending downwardly into the well and actuating a pump and attached at its upper end to a cross head which is suspended from a walking beam by two sucker rod supporting cables, the walking beam being reciprocated between limits by a prime mover, comprising in combination with said above enumerated parts: two arms, one clamped to one of said cables and the other clamped to the other of said cables and both disposed in a plane to which the polish rod is perpendicular; an expansible assembly having one endseated on the free end of one of said arms and its other end seated on the free end of the other of said arms, said expansible assembly having expansion springs so placed as to tend to force said ends of said expansible assembly apart and thus rotate each of said arms about its cable and force the free ends of said arms apart; a latch mechanism comprising a primary connecting member having a first end attached to the free end of one of said arms, a secondary connecting member having a first end attached to the free end of the other of said arms, and a connecting. assembly detachably connecting the second ends of said primary member to the second end of said secondary member in such a ber stops the prime mover.

5. A safety device for use in oil wells in which av polish rod is attached at its lower end to a string of sucker rods extending downwardly into the well and actuating a pump and attached at its upper end to a cross head which i suspended from a walking beam by two sucker rod supporting cables, the walking beam being reciprocated between limits by a prime mover, comprising in combination with said above enumerated parts: two arms, one clamped to one of said cable and the other clamped to the other of said cables and both disposed in a plane to which the polish rod is. perpendicular; an expansible assembly. having one end seated on the free end of oneof said arms and its other end seated on the .free end of the other of said arms, said expansible assembly having expansion springs so placed as to tend to force said ends of said expansible assembly apart and'thus rotate each of said arms aboutits cable and force the free end of said arms apart; means by Which the center of said expansible assembly is rigidly connected to the upper end'of the polish rod; and means by which the separation of the free ends of said arms stops the operation of the prime mover.

6. A safety device for use in oil wells in which a polish rod is attached at its lower end to a string of sucker rods extending downwardly into the well and actuating a pump and attached at its upper end to a cross head which is suspended from a walking beam by two sucker rod supporting cables, the walking beam being reciprocated between limits by a prime mover, comprising in combination with said above enumerated parts: two arms, one clamped to one of said cables and the other clamped to the other of said cables and both disposed in a plane to which the polish rod is perpendicular; an expansible assembly having one end seated on the free end of one of said arms and its other end seated on the free end of the other of said arms, said expansible assembly having expansion springs so placed as to tend to force said ends of said expansible assembly apart and thus rotate each of said arms about its cable and force the free ends of said arms apart; means by which the center of said expansible assembly i rigidly connected to the upper end of the polish rod; a latch mechanism comprising a primary connecting member having a first end attached to the free end of one of said arms, a secondary connecting member having a first end attached to the free end of the other of said arms, and a connecting assembly detachably connecting the second ends of said primary member to the second end of said secondary member in such a manner that said second ends are disconnected when the free ends of said arms are moved apart; and means by which the disconnection of said second ends stops the prime mover.

7. A safety device for use in oil wells in which a polish rod is attached at its lower end to a string of sucker rods extending downwardly into the well and actuating a pump and attached at its upper end to a cross head which is suspended from a walking beam by two sucker rod supporting cables, the walking beam being carried upon a support and reciprocated bet-ween limits by a prime mover, comprising in combination with said above enumerated parts: two arms, one clamped to one of said cables and the other clamped to the other of said cables and both disposed in a plane to which the polish rod is perpendicular; an expansible assembly having one end seated on the free end of one of said arms and its other end seated on the free end of the other of said arms, said expansible assembly hav'-- ing expansion spring means so placed as totend to force said ends of said expansible assembly apart and thus rotate each of said arms about its cable and force the free ends of said arms apart; means by which the center of said expansible assembly is rigidly connected to the upper end of the polish rod; a latch mechanism comprising a primary connecting member having a first end attached to the free end of one of said arms, a secondary connecting member having a first end attached to the free end of the other of said arms, and a connecting assembly detachably connecting the second ends of said primary member to the se ondend of saidsec- 9 10 ondary member in such a. manner that said sec- REFERENCES CITED ends are dlsconnected when h freg'end's 9! The following references are of record in the Sam arms are moved apart; a flexible nember me of this patent: having a first end attached to a. stationary part of said support and a. second end carried to said 5 UNITED STATES PATENTS connecting assembly and detachable therefrom Number Name Date whenever the second ends of said connecting 1,621,692 Sutton Mar. 22, 1927 members are disconnected; and means by which 2,166,410 Jackson July 18, 1939 the disconnection of said flexible member stops 2,199,583 Athy May 7, 1940 the prime mover.

GEORGE E. OWEN. HARRIS L. BRENDT.

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