US1891062A

US1891062A - Well drilling structure

Info

Publication number: US1891062A
Application number: US386468A
Authority: US
Inventors: John L Sager
Original assignee: Individual
Current assignee: Individual
Priority date: 1929-08-16
Filing date: 1929-08-16
Publication date: 1932-12-13
Anticipated expiration: 1949-12-13

Description

Dec. 13, 1932. J, SAGER WELL DRILLING STRUCTURE Filed Aug. 16, 1929 5 Sheets-Sheet 1 alf. A w /7 J L- SAGER DMn 13. 1932.

Filed Aug. 16. 1929 3 Sheets-Sheet 2 Inns/1 for fr Ay/(27M Dec. 13, 1932. J. L sAGER 'ELL DRILLING STRUCTURE Filed Aug. 16. 1925 3 Sheets-Sheet 3 /Wentor:

/f if MVMCING mlNOt.

llTRAcTlNQ tout. n

Patented Dec. 13, 1932 PATENT OFFICE JOHN L. SAGER, OF lLOS ANGELES, CALIFORNIA WELL DRILLING STRUCTURE Application illed August 18, 1929. Serial No. 386,488.

My invention relates to electro-magnetic recipiocatinr means, and more particularly to a novel so enoid-operated well drilling ap paratus.

Present Well drilling methods require such bulky and expensive equipment as to make the drilling of a well an expensive matter,

usually requiring expert help.

It is an object of the present invention to provide a well drillin ap aratus which is substantiall automatic w en in operation, and whic is yet simple in design and comparatively. cheap.

Affurther obj ect of the invention is to provide a reci rocating drilling mechanism which may Be suspended in a Well on any suitable supporting means and which is automatically advanced downward at the proper time to insure a maximum percussion.

In accomplishin the above 'and other objects I rovide a p urality of solenoids each of whic acts on a plunger, at least certain of these solenoids being o erable to exert a downward force on the p unger, and' certain others being adapted to exert an u ward force on the plun er, and it is one oft e important objects o this invention to rovide a pluralit of solenoids so arrange these solenoids eing hereinafter terme advancing and retracting solenoids for the purpose of clearness.

Ihave found that with such a combination it is preferable to ener e the advancing solenoids during the perio of energization of. the

retractng solenoids, and to then rapidly break the circuit through the retracting solenoids, thus allowing the advancing solenoidsto quickly accelerate the plun r on' the power or percussion stroke. I ave. found 0 that the acceleration of the plun er is very much faster if this procedure is fol owedthan it would be if the retracting and advancing solenoids are successively energized.' This is due to the fact that the current through a 5 highly inductive winding builds u very slowly, a major portion of a secon often elapsin before this current reaches a maximum. 'he magnetic flux is correspondingly slow to build up, and it has thus previouslg W been impractical to use the action of suc vretracting solenoids. A further object of the invention is to provide a drilling or reciprocatin structure built in units, each unit including a solenoid, so that any number of these units may be assembled, depending upon the strata being penetrated as Well as upon other factors,

and-so that any defective unit may be easily removed and replaced'.

Further objects of the invention lie` in the construction of these solenoid units, er se.

Still another object of the invention lies in combining a water-circulating system with a solenoid-operated reciprocating mechanism whereby the solenoids are water cooled, thus permitting the permissible safe current. in the windings to be greatly increased.

Another object of the invention lies in the provision of a cushion means for reventing theplunger from dropping from t structure. l

Still further objects and advantages of this invention will be evident hereinafter.

While I shall hereinafter describe in detail that embodiment. of my invention which 1 deem best for drilling purposes it should be 9 understood that I am not limited to this embodiment, certain of the details of my i1 xvention finding utility in other capacities Referring to the drawings:

Fig. 1 is a utility view illustrating my drill- 95 ingrapparatus in a well.

ig. 2 is a vertical sectional view of th drilling structure of my invention.

Fig. 8 is an enlarged view of a portion of Fig; 2.

e drilling l Figs. 4, 5, 6, and 7 are sectional views taken along corresponding lines of Fig. 2.

Fig. 8 is an enlarged view of another portion of Fig. 2.

Fig. 9 i's a general wiring diagram of the a paratus of my invention with certain of t e parts shown in perspective.

Fig. 10 is a wiring diagram of an alternative orm of advancing means of my invention.

Referring in detail to Fig. 1, I have shown a well 10 being drilled by a drilling structure 11 of my invention this structure being suspended in the well by means of a supporting means illustrated in the form of a wire cable 12 which extends over a sheave 13 rotatably supported in a tri od or derrick 14. The en of this wire cab e is wound around a lowering means inthe form of a drum 15' so that by rotating this drum the drilling structure 11 may be raised or lowered in the well.

The drilling structure 11 is formedof any number of solenoid units 16 separated by spacing structures 17. In Fig. 2 I have shown a cross section of such a drilling structure as providing two solenoid units 16 and two spacing structures 17, and being adapted to reciprocate a lunger 18 whereby the well 10 is deepened t rough the action of a bit 19 attached to'the lower end of this plunger.

The upper of these solenoid umts has been termed a retracting unit 20 while the lower one has been termed an advancing unit 21, this nomenclature being used because of the respective functions of these units in retracting and advancing the plun er 18. Inasmuch as the solenoid units are su stantially identical, as are also the spacing structures 17 only the uppermost solenoid unit and spacing structure will be specifically described.

Referring in articular to Fi s. 2, 3, 5, 6 and 7, the nove .solenoid unit o my invention is housed in a shell 22 formed of magnetic material and having primary and secondar counterbores 23 and 24 which are threa ed to respectively receive primary and

secondary plugs

25 and 26 which are in turn adapted to bear against primary and

secondary plates

27 and 28 in a manner to force these lates into firm engagement with the shoul ers defining the ends of the counterbores 23 and 24 in which they are respectively positioned.

Formed respectively in the

plugs

25 and 26 are

packing chambers

31 and 32 into which are threaded primaryand secondary retaining

members

33 and 34, each of these members having an annular channel 35 adapted to snugly en age the periphery of an inner tubing 36 ormed of a sutablenon-magnetic material. The retaining

members

33 and 34 are adapted to be screwed into their respective packing chambers by means of a suitable Wrench extending into openings 36a thereof these members engaging the opposite ends o thel inner tubing 36 in abutting relationshi A suitable packing 37b is retained in eac of the

packing chambers

31 and 32 and is adapte to be compressed by the retaining

members

33 and 34 against the walls of these packing chambers and againf. the periphery of the inner tubing 36 wher; the retaining members are in abutting relationshipl relative to the ends of the inner tubing 36, ereby forming a fluid-tight joint `between the inner tubing 36 and its associated plugs and retaining members. The solenoid unit 16 is so designed that when the retaining members are-in this position, and when the.

plugs

25 and 26 are in engagement with the plates 27 and28, the faces of the plugs and retaining members are flush with the respective ends of the-'shell 22. 1

'Pressed tightly into a central o'ening of eachretaining member is a suita le sleeve adapted 'to loosely journal the plunger 18 in its reciprocatory m'otion, these sleeves being respectively designated as 'primary and

secondary sleeves

37 and 38. he primary sleeve 37 is usually, though not invariably, formed of magnetic material, while theseconda sleeve 38 is formed of non-magnetic material, the utility of thus forming 'the sleeves being evident hereinafter. The primary and

secondary plugs

25 and 26 thus re spectively cooperate with the retaining mem `ing 36 so as to provide an annular wiring space 41 therebetween in which space are positioned the wires connecting the groups of the winding 40, these wires extending through notches 42 cut in the

plates

27 and 28 and into rima germe by cavities respectively cut in the

plugs

25 and 26 adjacent the

plates

27 and 28. A passage 45 communicates with the pull box 43and extends upward throu h the primary lug 25, there being a sim' ar passage 46 lbrmed through the secondary plug 26.

Each spacing structure 17 is provided with uplper and

lower flanges

47 and 48 through wA ich Vca screws 49 extend in a manner to be threa edly received by the plug there- "adjacent, y A spacing structure 17 is thus clamped to each end` of the solenoid unit 16. A plurality of ribs 50 extend longitudinally of each spacing structure between the

flanges

47 and 48, one of these ribs being cored to form a passage 51 in alignment with the pasand secondary pull boxes 43 and 44- sages 45 or 46 and adapted to retain the conductors suppl ing current to the solenoid units 16, as we l as any control conductors.

These conductors extend upward through a assage 52 formed lon 'tudinall throng a rib 53 of a strainer 54 ormed wi a air of flanges 55 and 56 which are respective bolted or otherwise secured to a flange 57 o acap member 58. This cap member rovides a wire chamber 59 which 'communicates with the u per end of the passage 5l through a radia passa best shown in `ig.2.

The con uctors leave the cap member through a suitable packer 60 preferably in the form of an insulator and extend u ward around a hook 61 to the main .wire ca le 12 the hook 61 being attached to the lower end of this cable and serving to support the drilling structure 11 through an eye 62 formed integral with the cap member 58. The wire cable 12 is shown in cross section in Fig. 4 and is composed 4of stranded sections 63 formed of a material of high tensile strength and surrounding power conductors 64 in protecting relationship, these power conductors carrying current to the drilling structure and also providing any control wires desirable in operating this structure.

The advancing unit 21 houses an advancing solenoid winding 68 in a manner pieviously described for the retracting unit 20. The construction of these two units is substantially identical except that the plu -fitting in the lower end of the shell 22 provi es a channel 7 4 corresponding to and serving the same purpose as, the channels provided in the retaining `

members

33 and 34 and into which the inner tubing 36 extends. A packin chamber is formed in this plug and a gland 76 compresses a packing 77 therein and pressurally against the peripheral surface of the lunger 18.

T e plunger 18 is composed of alternate sections formed of magnetic and non-magnetic material which are of the same external diameter and preferably threaded together as shown2 the former acting as armatures for the solenoid units and the latter :acting as spacers therefor. For the purpose of clearness I have termed the upper section formed of magnetic material as a'retracting armature 78, and the lower section of this materia-l as an advancing armature 79, the section of nonmagnetic material therebetween being designated as an intermediate spacer 80. Similarly the section of non-magnetic material below the advancing armature 79 has been termed a bit-retaining member 81 due to the fact that the bit 19 is attached thereto.

The magnetic path through the retractin unit 20 includes the shell 22, the plugs 25 an 26, and the retaining

members

33 and 34--all formed of magnetic material-and also includes the

sleeve members

37 and 38, and that portion of the retracting armature 78 lying between the retaining members. If this armature is centrally disposed relative to the remainder of the magnetic circuit the length thereof is sufficient to bridge the sleeve members 87 and 38 so that the reluctance of the ma etio ath will be a minimum, the ition o maximum upward thrust being just before this armature bridges the sleeve members. In some instances I have found it desirabo to form the primary sleeve member 87 of ma etic material and the secondary sleeve mem r 38 of non-magnetic material so that the action between the former sleeve member and the retractin armature 78' when the retracting solenoi is energized is one of two ma ets in physical contact with each other. is contact magnetic action strongly tends to maintain the pluri er in its upper orretracted position during t e eneigization of the advancing solenoid, but this force is quickl removed when the solenoid is de-ener ize If this action is not desired it is essenti that both the

sleeve members

37 and 38 be formed of non-magnetic material to prevent-magnetic binding of the plunger thereto when the solenoid winding is energized and when quick action of the plunger is desired. l

'Similarly' it is sometimes preferable to form the upper sleeve member of the advancing unit 21 of non-magnetic material and to form -the lower plug and gland 76 of magnetic material', thus tending to exert a very powerful downward thrust on the advancing armature 79 just prior to the instant that this armature moves downward into contact with the magnetic material forming the lug. This position of maximum downward t rust which is reached just prior to contact between the advancing armature 79 and the plug is a very important one in the drilling art as will be hereinafter explained.

It will be noted from Fig. 2 that the intermediate spacer 8O is of such length that the center-to-centei` distance between the armatures 78 and 79 is different from the centerto-center distance betweenthe retracting and advancing

units

20 and 21, -this distance in the preferred embodiment of my invention being less than the latter distance. Thus b alternately energizing the retractii and ad) vancing solenoid windings 40 an plunger 18 will be reciprocated.

I have found, however, that such an alternate energization does not give the desirable blow obtainable if the retracting solenoid is first energized followed by a similar energi-l zation ofthe advancing solenoid and a subsequent de-energization of the retractin solenoids. This desirable cycle I accomplis by means of a timing device best illustrated in Fig. 9 which illustrates advancing and retracting relay contacts 90 and 91 formed of spring steel and tending to respectively engage

contacts

92 and 93 when not lifted there- 68 the from b cams 94 and 95. These cams are mounte on a sin le shaft 90 which is driven by a small varia e-spced motor 97 throu h a suitable speed-reduction means 98. e

- relay contacts 90 and 01 are respectively connected to solenoids 100 and 101by conductors 102 and 103, the remainin terminals of these solenoids bein connecte together by a conductor 104 whic also extends to a source of electric energy indicated as a generator 105, this generator being connected to the citacts 9 and 93 by means of a conductor The solenoidslOO and 101 respectively act when enegized to pivot

armatures

108 and 109 .aroun a pivot shaft 110 against the ac- .tion of springs 111 and 112 in a manner to close the main contacts supplying current to the solenoids of the drilling structure. These main contacts comprise a pair of contacts numbered respectively 113 and 114 which are connected to the generator 105 by a conductor 115 and which lie in the path of travel of spring contacts 117 and 118 mounted on the

armatures

108 and 109.

The contacts 117 and 118 are preferabl formed so as to be uickl and easily replace this being accom islie by means of thumb screws 11,9 threadbd into the armatures and bearing against these contacts.

Conductors

120 and 121 res ctively connect the contacts 117 and 118 to s ip rings 122 and 123 mounted,

A.on one end of the drum 15, these slip rings being respectively connected to the advancing 'and retracting solenoids of the drilling structure through the conductors 64 of .the cable 12. Current returns from both theadvanc- -ing and retract-ing solenoids through a common return conductor 125 which ends in a slip ring1126 from which the curr-nt is conducted to t e generator 105 through a suitable brush and throu h a conductor 127.

Due to t e high inductance of the retracting and advancing solenoid windings it often is necessary to use quick-acting circuit breakers and auxiliary means for quenchin the arc formed when the circuits are opens This is especially true of the circuit including the retracting solenoid, for the strength of the blow delivered is materially decreased by any current passing through the arc formed between the contacts 114 and 115 when separated during the period of energization of the advancing solenoid. For Ithis reason I have shown aA magnetic blow-out means for these contacts,this means comprising a magnetic core 130 bridging the gap formed by the cony tacts 114 and 118 when se arating, the magnetic ux being. formed y a winding 131 around one leg of the core 130, this winding being connected across the generator 105 through a switch 134. It is usually preferable 4to use a similar blow-out means for the contacts 113 and 117 to'prevent undue pitting of these contacts due to arcing conditions.

The currents required in operating the sc lenoids is sometimes large enou h to require nn external cooling means for t ese solenoids. Such a means is incorporated as an integral art of my drilling structure and utilizes a on itudinal bore 149 of tlie spacing structure 17 a ve the retracting unit 20 as a cylinder in which a piston 150, formed integral with the uppermost non-magnetic section 151, may reciprocate when the plunger moves. This piston carries the customary workin valve 152 which controls the passage o fluid throu h a longitudinal passage 155 formed comp etely through the plunger 78 and which communicates with a passage in the bit 19 which directs the discharge of this fluid adjacent a cutting edge of the bit, thus aiding in drilling and in keeping the bit clean.

l This fluid is drawn through relatively large openings formed through the walls of the strainer 50 and passes through a standing valve 159 screwed or otherwise secured in the lon itudinal bore 149. The standing valve an the openings of the strainer 50 are so formed as to have relatively large Huid-carrying capacities so that the umping means will not materially slow up t e downward or power stroke of the mechanism. The space below the piston 150 may freely receive and discharge air or liquid through the

sleeves

37 and 38 and around the peripher of the plunger. In order that no retarding eilect maybe thus setI up, the journalling openings of the sleeves may have longitudinal channels 161 cut therein as best shown in Fig-7.

The piston 150 prevents the plunger 18 from drop ing from the drilling structure, but the weight ofthe plunger is ordinarily large and to prevent possiblel dama e should the current be cut oil' when the drillin structure is a distance from the bottom of t e well, or should the bit 19 penetrate an excessively soft formation, I prefer to provide a cushior.- i

means acting between the piston 150 and the top ofthe retracting unit 20.

This cushion means may be any suitable hydraulic one or may be of the type illustrated in which compression springs 162 rest on the upper face of the primary plug 33 and lie in the path of travel of the piston 150 when moving into its lowerniost position, it being understood that the springs come into pla only after the solenoid has passed the position of maximum thrust when moving downward.

If maximum drilling efiiciency. is to be achieved it is very desirable for the operator to know the position of the plunger relative to the drilling structure at or toward the end of each stroke. The desirability of this will be apparent when considering the characteristics of such a drilling structure as described wherein the maximum downward thrust on the plunger occurs just before the advancing armature 79 bridges the magnetic ga of the advancing unit 21 andwherein t is portion of the stroke is used 1n actual drillm to secure maximum percussion. It is usua ly desirable that the instant of impact be at or just before this position of maximum downward thrust. If the drilling 'structure is positioned a trifle too deep in the well, this position of maximum downward thrust is never reached and thefull eiciency of the structure is not utilized.

For the urpose of indicati to the operator whet er or not this position of maximum downward thrust is reached on each reciprocation I provide a roller 200, best shown in Fig. 8, which is rotatably mounted in a support 201 which in turn is secured to a flexible diaphragm 202 flexed in such a manner as to cause theroller to pressurally engage the periphery of the plunger 18 at all times. An annular groove 204 is formed in the intermediate spacer 80 in such a position that the roller moves thereinto when the plunger is at a control position, which position is just prior to the relative positions of advancing armature and advan"1ng solenoid for maximum downward thrust.

A switch contact 205 is mounted on the opposite side of the diaphragm 202 from the roller 200 and engages a spring contact 207 suitably mounted in a switch cavity 208 of the spacing structure, when the roller enters the annular groove. The engagement of these contacts completes a `control circuit which includes a conductor 210, the common conductor 125, a slip ring 212 carried by the drum 15, a conductor 213 extending to the generator 105, and an indicating means in the form of a signal lamp 215. Thus, when the signal lamp 215 islighted the operator knows that thc drilling structure may be further lowered and that the plunger is moving through the osition of maximum thrust.

It is often desirable to make this advanceward by a spring 227 but which is drawndownward by the action of a solenoid 228, the winding of which is energized from a battery 229, or other source of electric potential, in circuit with a time-limit relay 230, the time setting of which may be readily changed by moving a thumb screw 231. The control winding 232 of this time-limit relay 'may be connected in parallel with the signal lamp 215 so as to be energized each time the signal lamp is energized. The setting of the time-limit relay thus varies the time of eneration of 'che solenoid 228 and thus the time t at the brake 225 is released.

In Fig. 10 I have illustrated an alternative automatic advancing means which includes a 'ositive drive means for advancing the dri ling structure. This is accomplished by a motor 241 connected to the drum 15 by a link belt 242 or other speed-reduction means. A quick-operating magnetic brake is used on the motor shaft, the winding of which is indicated Aby thenumeral 243. This type of magnetic brake is held in locked position by spring-operated means and is released only during the energization of the winding 243. Inasmuch as this winding is connected directly across the supply terminals of the motor, it follows that such a magnetic brake insures quick stopping of the motor the instant the power supply thereof is shut olf. This supply of power is controlled by a suitable time-limit relay 245 of any suitable design, such, for instance, as one having a dash-pot for retarding the opening o'f the ower circuit once the control circuit has een energized. This control circuit is connected supply conductors for this purpose which extend through the wiring space 41, the

pull boxes

43 and 44, and through the passages 45 and 46, these conductors extending slightly beyond the latter passages to permit splicing to a similar pair of conductors extending through the passage 51 of the spacing structure 17 which is to be subsequently secured thereadiacent. After this splice has been made the bolts 49 are secured in place, the excess wire being forced into the-pull box thereadjacent. Any number of solenoid units may be thus assembled, it being understood that the supply conductors of the advancing units extend through the passages of the retracting units, as does also the control wire 210 from the roller-operated switch.

The desired number of magnetic and nonmagnetic sections are then assembled to form the plunger 18 which is put in place before the spacing structure is secured to the uppermost unit 20. The supply and control conductors are then spliced to the conductors 64 of the wire cable 12 and the excess wire forced into the chamber 59 of the cap member 58.

The drilling structure is then lowered into the well and the motor 97 energized. As the cam 95 moves, the spring contact 91 lowers thus completing a`circuit from the generator through the

conductors

103, 104 and 106 in a manner to energize the solenoid 101 which attracts the armature109 against the action of the spring 112 to move the contacts 114 list and 118 into engagement. This energizes the retracting solenoid 20 through the conductors 115, the generator 105, the conductor 127, the slip ring 126, the current then passing through the conductors 64 of the wire cable and through the grou s of the retracting unit 20 and returning t rough the slip ring 122 and conductor 121.

The energization of the retracting solenoid draws the plunger up until the retracting armature 78 bridges the magnetic path of the retracting unit 20 and lies in such a position that it contacts the sleeve 37.

During the time that the cam 96 allows the contacts 91 and 93 t-o close, the cam 94 turns into such a position that the contact enga es the contact 92, thus completing a circuit through the solenoid 100 through the

conductors

102, 104, and 106. This energizes the solenoid 100 to close the contacts 113 and 117 which'in turn completes a circuit through the conductor 120, the slip rings 122 and 126, and the conductors 127 in a manner to energizel the advancing solenoid. This does not materially move the plunger downward,how ever, due to the contact magnetic action between the sleeve 37 and the retracting armature 78 but exerts a strong downward force on this plunger.

When the flux through the advancing solenoid has built up to a maximum, the cam 95 operates to separate the contacts 93 and 95 thus de-energizing the solenoid 101 andallowing the spring 112 to separate the contacts 114 and 118. The switch 134 having been previously closed, the arc which is formed between these latter contacts is quickly blown out by the magnetic blow-out means which places these separating contacts in a strong magnetic field. The current through the retracting solenoid is thus quicklyreduced to zero, and inasmuch as the retracting force is thus removed from the armature 78 the lunger moves swiftly downward under the influence of the advancing solenoid. Due to the fact that the flux of this advancing solenoid has previously built up to a maximum, this downward movement of the plunger is fast, and the blow struck by the bit 19 is a very hard one, especially if the instant of impact occurs just prior to the instant that the maximum downward thrust is 4exerted on the plunger.

Subsequently the cam 94 moves into such a position as to separate the contacts 90 and 92, thus breaking the circuit through the advancing solenoid upon separation of the contacts 113 and 117, after which the cycle is repeated.

If the plunger ymoves downward a suflicient distance for the roller 200 to enter the annular channel 204, the signal lamp 215 will light. If the lowering of the drilling unit is being manually controlled` this is a signal that the drum 15 can be turned slightly to allow a slight lowering of the drilling structure. After this lowering it may be several strokes of the plunger before the bit has penetrated suiiicient to allow the roller to again engage the annular channel. In this way the operator attempts at all times to keep the signal lamp fiashing and yet advance the drilling structure at such a rate that the time interval between flashes immediately after each lowering will not be excessive.

Should the drilling structure be lowered too fast, or should the bit encounter an evcessivel hard strata, this signal lamp will fail to light and the operator will draw upward on the cable until such time as the signal lamp again lights with each reciprocation, after which he will relower the drilling structure more slowly.

In the event that automatic operation is desirable, the time-limit relay is connected across the terminals of the signal lamp so that each time an electric impulse passes through the control circuit the cable will be lowered by an amount determined by the setting of the time-limit relay. I prefer to so set this relay that theamount of advancement is each time somewhat greater than the distance penetrated by the bit on each stroke, thus allowing several strokes to be completed between advancements. This is not, however, necessary where the number of strokes .'per minute is low.

While I have described the drilling structure as comprising a single retracting sole- .noid and a single advancing solenoid, it

should be clear t at this has been done only for the purpose of clearness and simplicity. In actual drilling it is often necessary to use as man as ten retracting and ten advancing units, t iough it is not necessary that the number ofretracting and advancing units be equal. For these additional units I prefer to use a solenoid unit such as that described in detail for the retracting unit 20, the additional retracting units and the corresponding spacing structures being inserted at a section A-A of Fig. 2, these units being inserted with the primary sleeve 37 of each unit upward so that the contact magnetic action when the plunger is retracted will be 0btained. Similarly the units to be used as retracting units are inserted, together with a corresponding number of spacing structures, at a section lf3-B and are secured in place with the primary sleeves 37 of eaoh downward, thus increasing the thrust in a downward direction just prior to the instant that the advancing armatures contact therewith.

It is not, however, necessary in all cases to use one sleeve of magnetic material and the other of non-magnetic material for very desirable results can also be obtained by making both of non-magnetic material so that no magnetic binding takes place at any portion of the stroke.

While I have shown and described a preferred embodiment of my invention and a preferred method of operation therefor, it should be clear that various modifications might be made therein without departing from the s irit of this invention. Thus chan es in orm and proportion of many of the e ements might be made to t circumstances under which the drilling structure is to be operated, and the particular method of threading the plu s and retaining menibers in place ma e ispensed with in favor of other metho Certain features of my invention are furthermore not limited to a drillin structure of the type shown but may be use on other reciprocating mechanisms. The particular cycle of operations is an important part of this invention, as is also the provision of means for circulating the water in the well in coolinv relationship with the solenoid windings, fortby the latter means I .am able to operate the drilling structure with the magnetic ths of the solenoids substantially saturate without dan er of overheating. Asbestos impregnate windings may be resorted to in certain installations wherein the water is not cold or wherein drilling is especially difficult, thus greatly increasing the life of the solenoid units under heated conditions. The particular unit type of construction is also an important part of my invention, as is also the indicating means at the top of the ground and the automatic advancing means. Various methods of accomplishing this automatic advancement will be apparent to those skilled in the art, the two systems shown in Figs. 9 and 10 being illustrative only.

I claim as my invention:

1. In a drilling structure, the combination of: a plunger; a primary solenoid means for moving said plunfrer in a given direction; a secondary solenoid means actin on said plunger in a direction opposite to t at of said primary solenoid means; supply means for energizing said primary and secondary solenoid means; control means for de-energiz'ng said rimary solenoid means during the period) of energization ofsaid secondary solenoid means; and means for quickly decreasing the current in said primary solenoid means when said primary solenoid means is de-energized.

2. In a drilling structure, the combination of: a plunger having upper and lower sections of magnetic material segarated by a section of non-ma netic materia u per so`.e noid means arouz. said plunger an adapted to act on said up er section of magnetic material; lower solenoid means around said plunger and adapted to act on said lower section of magnetic material, said upper and lower solenoid means being spaced center-tocenter a distance unequal:` to the center-tocenter spacing of said sections of magnetic material; and upper and lower closure means at each end of each of said solenoid means the up er and lower closure of each solenoi means eing spaced a distance apart substantially equal to the length of itscorresponding section of magnetic material whereby said sections of ma netic material bridge the closure means o said u per and lower solenoid means when said p unger is in an upper and a lower position respectively.

3. In a drillin structure, the combination of: 'i plurality o substantiall identical solenoid units; a plurality 0% substantially identical spacing structures, one of said spacing structures being positioned between each oair of said solenoid units; individual means or securing each spacing unit to the solenoid units on opposite ends thereof whereby any solenoid unit ma be re laced without disturbing the remainder o the solenoid units; and a plunger slidable relative to said solenoid units and said spacing structures, said plunger being formed of a ternate magnetic and non-magnetic sections.

4. A combination as defined in claim 3 including conductors for connecting said solenoid units together and in which each of said solenoid units provides pull-box means into which an excess lengths of said conductors may be orced when assembling said drilling structure.

5. A combination as defined in claim 3 in which said spacing structures provide passages formed therethrou h and which communicate with passages ormed in said solenoid units when properly secured thereto.

6. In a solenoid unit of the class described, the combination of: a shell; a central plunger-receiving tubing extending through said shell; means at opposite ends of said shell and extending between said shell and said central tubing for defining an annular space therebetween; a packing means sealing each end of 'said annular space; and a winding in said annular space.

7. In a drilling means, the combination of: a drilling structure positioned in a well and comprising solenoid means energized from the to of said well; plunger means adapted to be oth raised `and lowered by said solenoid means; drilling means actuated by said plun er means; lowerin means at the top of said well for controlling the position of said drilling structure in said well; and means operated as a function of the degree of advancement of said plunger means relative to said solenoid means for controlling the movement of said lowerin means.

8. In a drilling means,t e combination of: a drilling structure positioned in a well and comprising solenoid means energized from the top of said well; plunger means adapted to be both raised and lowered by said solenoid means; drilling means actuated by said plunger means; lowering means at the top of said well for controlling the osition of said drilling structure in said we l; a switch in said drilling structure; means for operating said switch when said plunger has reached a position just prior to the position of maximum thrust; and control means for controlling said lowering means and operatively connected to said switch.

9. In a drilling means, the combination of: a drilling structure positioned in a well and comprising solenoid means energized from the to of said well; lunger means adapted to be oth raised an lowered by said solenoid means; drilling means actuated by said plunger means; lowering means at the top of said well for controlling the position of said drilling structure in said well; a switch in said drllling structure; means for operating said switch when said plunger has reached a position just priorto the osition of maximum thrust; and a time-limit relay electrically connected to said switch for controlling said lowerin means.

10. A met od of applying slow buildingup forces in effective quick motion of an element, which includes the steps of: building up of one of said forces to move said element into a retracted position; building up a second force acting on said element in opposition to the first force; and suddenly removin saidJlirst force during the application of sai second force to allow said second force to Aquickly advance said element.

11. In a drillin structure adapted to be lowered into a weIl containing a liquid, the combination of: solenoid means; a hollow plunger adapted to be reciprocated by said .solenoid means; and a pumping means associated with said plunger and operated by a reciprocation thereof for circulating said liquid throu h said plunger.

l2. In la rillin structure ada ted to be lowered into a wel containing a iquid, the combination of: solenoid means; a hollow plunger adapted to be reciprocated by said solenoid means; walls defining a cylinder in said drilling structure into which said plunger extends, said cylinder communicating with the' interior of saiddplunger through a valved passageway; valve inlet means for conducting` said liquid into said cylinder; and a piston on said plunger for drawin said liquid into said cylinder and circulatin it through said plun er in cooling relations ip' with said solenoi s.

18. In combination: a shell; a central tubing extending through said shell; rimary and 'secondary closure means exten ing between said shell and said central tubing to define an annular space; a winding in said annular space but smaller than said annular space to provide a wiring space between itself and one wall of said annular space; walls defining a passa e through each of said primary and secon ary means; means positioned at opposite ends of said shell for preventin communication between the interior of sai central tubing and said passages of said means, and roviding passages communicating with said first named passages; and conductors carrying electric current to said winding and extending through-all of said passages.

14. In combination: a shell; a central tubing extending into said shell and cooperating therewith in defining an annular space closure means extending between one end of said shell and said central tubing, said central tubing engaging said closure means; closure means at the other end of said shell and movable therein toward said first named closure means to compress said central tubing between said closure means; and a winding in said annular space.

15. In combination: a solenoid unit comprising a shell, a central tubing spaced to orm an annular space therebetween, and a winding in said annular space; a spacin structure adapted to be secured to the end o said solenoid unit and providing a passage; conductor means positioned in said assage and electrically connected to said Winding; and Walls defining a pull box adjacent that end of said solenoid unit to whi ch said spacing structure is secured and into which any excess conductor means may be forced when said solenoid unit and said spacing structure are being assembled.

16. -In combination: a shell formed of magnetic material; a winding in said shell; a plunger movable through said winding; a primary annular closure means extending across one end of said shell and providing an opening only slightly larger in diameter than said plunger, said primary closure means being formed of magnetic material; and a secondary closure means providing an opening only slightly larger in diameter than said plunger and bounded .by walls formed of a non-magnetic material, said plunger being formed of magnetic material and being of sufficient length to bridge said primary and secondary closure means, whereby an extremely strong pull is exerted on said plunger when one end thereof is approaching said primary closure means.

17. A combination as -defined in claim 16 including a percussion tool attached to that end of said plunger closest to said primary closure means.

18. In a drilling structure, the combination of: a plunger having upper and lower sections of magnetic material se arated by a section of non-magnetic materia ,upper solenoid means around said plunger and adapted to act on said upper section of magnetic material; lower solenoid means around said plunger and adapted to act on said lower section of magnetic material; means formed of magnetic material associated 'with one of said solenoid means and contasting said plunger to exert a contact magnetic action on one section of said plunger., when said plunger is in an u per position; and means formed of magnetic material associated with the other of said solenoid means and contaeting said plunger to exert a contact magnetic action on the other section of said plunger when said plunger is in a lower position.

19. In combination: a shell formed of magnetic material; a primary and a secondary closure means extendin inward from opposite ends of said shell an providing openings; a plunger only slightly smaller in diameter than said openings so as to be slidably journalled therein; a central ltubing formed of non-magnetic material and extending between said closure means, said central tubing providing an inner wall of greater diameter than said opening so as to be spaced from the surface of 'said plunger, said shell and said closure means cooperating with said central tubing in providing an annular space; and a winding in said annular space and capable when energized of exerting a pull on said plunger.

20. In combination: a plunger; a primary solenoid means acting when energized to retract said plunger; a seconda solenoid means acting when ener ized to a Vance said plunger; primary switc means for energizing said primary solenoid means to retract said plunger; secondary switch means for energizing said secondary solenoid means; means for closing said secondary switch means during the energization of said primary solenoid means whereby both of said solenoid means act on said plunger in opposite directions; and means for opening said primary switch means to de-energize said primary solenoid means durin the period of energization of said secon ary solenoid means to advance said piston under the action of the force exerted by said secondary solenoid means.

21. In combinationra plunger; a primary solenoid means acting when energized to retract said plunger; a seconda solenoid means actin when energized `to a vance said plunger; and means for energizing said solenoid means in a cycle comprising energization of said primary solenoid means to retract said plunger, subse uent ener 'zation of said secondary solenoi means uring the eriod of energization of said primary solenoid means, de-ener ation of said rimary solenoid means uring the energization of said secondary solenoid means thereb to advance said plunger, and subsequent e-energization of saidv secondary solenoid means to complete said cycle before the re-energization of said prima solenoid means on asucceedin cycle.

22. n a drillin structure adapte to be lowered into a we the combination'of: a

plurality of annular solenoids; a plunger extendin through said solenoids and reciprocated t ereby, said plunger lproviding a central bore therethrough; walls at one end of said pluralit of solenoids and defining a cylinder into w ich one end of said plunger extends; discharge valve means through which said central bore communicates with said cylinder; and a relativel large intake valve means communicating etween said cylinder and a body of cooling liquid whereby on the retracting movement of said plunger cooling liquid is forced through said central bore in cooling relationship with said solenoids and on the advancing movement of said plunger a new su ply of said cooling liquid moves into said cylinder throu 'h said relatively large intake means and e ecting a minimum of retarding action on said lunger.

In testiinon whereofp I have hereunto set my hand at os Angeles, California, this 14th day of August, 1929.

JOHN L. SAGER.

CERTIFICATE OF CORRECTION.

PatentNo. 1,891,062. December 13, .932.

JOHN L. SAGER.

that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 8, line 25, claim I0, for "effective" read "effecting"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of February, A. D. i933.

It is hereby certified M. J. Iiioore.

(Seal) Acting Commissioner of Patents.