CA1078369A - Device whereby a duct in a deep bore hole is supported and moved up or down by reaction against the bore hole surface - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A duct section or other load to be moved axially along a bore hole has two reciprocating drivers mounted on it and two sets of gripping elements. Each driver reacts axially between the load and a set of gripping elements to move the gripping elements relative to the load through a defined stroke in each axial direction. An endless cable with axially extending straight stretches has one stretch connected to each driver to constrain the drivers always to move in opposite axial directions and to begin and end their strokes simultaneously. The gripping elements are so formed that when engaged with the surface of a bore hole, increasing axial force on the load in one direction increases the radially outward force under which they bite into the surface. At each end of a driver stroke the gripping elements collide with abutment members of a direction control device, whereby gripping elements engaged with the bore hole surface are forced out of such engagement and dis-engaged gripping elements are forced against that surface. The abutment members are arranged in two sets, one set to coordinate gripping element engage-ment and disengagement for transporting the load in one axial direction, the other set for transportation in the opposite direction. Positioning the directional control device at one or the other limit of its rota-tion brings one or the other set of abutment members into use.

Description

* * *

This invention relates to apparatus for drilling very deep bore holes into the earth, and is more particularly concerned with apparatus by which a duct or shaft that extends along the length of a bore hole and i8 supported by reaction against the side surface of the bore hole is moved upwardly and down-wardly to raise and lower a drilling mechanism that i8 connected to the bottom of the duct.

For drilling a very deep bore hole into the earth, a drillin~ mechanism working a$ the bottom :

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10'7836~ , of the bore hole must be communicated with the surface by means of a shaft or duct that extends along the length of the bore hole. In prior apparatus for deep drilling, the drilling mechanism comprised a fluid pressure motor that was directly coupled to a bit or bits to drive the same, and the duct that extended down the bore hole carried pressure fluid to the motor.
Exhaust fluid from the motor was returned up the bore hole externally of the duct, carrying with it debris loosened by the drilling mechanism. In such prior apparatus the duct was supported at the surface of the earth and hung down into the bore hole, and therefore drilling depth was limited to something less than the so-called breaking length of the duct.
If the length of the duct exceeded a certain limit -usually somewhat less than 6,000 meters - the weight of the duct would exceed its tensile strength and the duct could be expected to break. Hence the maxi-~ mum depth to which a bore hole could be drilled has ; 20 heretofore been less than 6,000 meters.
Apparatus that enables bore holes tobe drilled to depths substantially greater than 6,000 meters makes possible the utilization of geothermal :`
energy in non-volcanic regions. It is estimated that temperature in the primary rock formation rises about 30 C per kilometer of depth. In a bore hole drilled to a depth of about 10,000 m., water or a similar fluid heat transfer medium, circulating in a closed system, 1~7836~9 can be forced down to abstract heat energy from the rock formation and back up to the ~urface for utili-zation of its heat energy content. Thus the capa-bility for drilling to such depths has great potential value in making available an inexhaustable energy æource.
The applicant's copending application, ~ Serial No. ~ 9 o ~ ~ l 1 , filed ~o~e~r ` Q generally covers apparatus which makes possible the drilling of such`extremely deep bore holes. In that apparatus there is an air-tight lining in the upper portion of a bore hole to be deepened, extending through porous and fissured rock formations and a short distance down into dense, air-tight bedrock;
and there is an air lock in the uppermost portion of the bore hole. Extending up through the entire length of the bore hole i8 a duct, made up of endwise con-nected, readily disconnectable duct sections, and the ~ upper end of that duct, which projects through the Z 20 air lock, is open to the atmosphere. The portion of ..
the bore hole below the air lock and ex`ternal to the duct is pressurized, and a pneumatic motor that drives the drill bit or drill bits has its pressure air inlet open to the bore hole outside the duct and itæ exhau~t air outlet communicated with the interior of the duct.

Instead of being suspended from the surface, the duct i5 supported by means of supporting and moving devices which are fixed to duct 6ection~ at _ 4 _ 11~78369 intervals along its length and which have gripping elements that frictionally engage the side surface of the bore hole. The drilling mechanism has a telescopingconnection with the bottom of the duct so that it can deepen the bore hole to some extent by moving downwardly relative to the duct while the duct remains stationary. However, when the drilling mechanism has worked down to the limit of extension of the telescopingconnection, the duct must be lowered through a distance sufficient to contract the telescoping connection and allow drilling to continue. It is also necessary that the drilling mechanism be brought up to the surface from time to time, so that worn drill bits can be exchanged for sharp ones. For this purpose, the duct must be raised as well as lowered, to carry the drilling mechanism up and down the bore hole with the duct by means of its telescoping connection with it.
Heretofore no satisfactory device has been known whereby an upright duct can be supported -from the side surface of a bore hole and, by reaction against that side surface, can be confined against motion or be moved upwardly or downwardly, as desired.
U.S. Patent No. 2,946,578 disclosed a machin`e having coaxial front and rear portions, the front portion comprising a drilling mechanism and the rear portion being provided with axially spaced sets of inflatable cushions. The cushions of each set were arranged around the machine in such a manner that, ~78369 when inflated, they frictionally engaged the side surface of the bore hole in which the machine was working, and when deflated they were clear of that surface. The respective sets of cushions were S attached to parts of the machine that were axially movable relative to one~another. Therefore, with a first set of cushions inflated, the part of the machine carryinglan adjacent second set of uninflated cu~hions could be moved axially towards or away from the inflated set. The se~ond set of cushions could then be inflated, after which the first set of cushions could be deflated and moved axially in the same direction relative to the second set. In this ~
way the machine could propel itself in each direction along a bore hole,~or maintain a fixed position.

In a pressurized bore hole~ inflation of the cushions would have presented a problem.
Furthermore, the apparatus was not suitable for use in vertical bore holes because the frictional en-gagement between its cushion surfaces and the bore hole surfacè would not have provided enough grip to - support any substantial amount of weight.
`
U.S. Patent No. 3,185,225 disclosed apparatus for feeding a drilling mechanism in the direction in which boring progressed. The apparatus comprised two sets of anchor assemblies that were ~equentially operable, so that each set, in turn, could be engaged with the bore hole surface while the other `-` 1078369 set of anchor assembles, which was retracted to be radially spaced from the bore hole surface, moved axially through a short distance in the drilling direction. Each anchor assembly comprised a plurality of elongated beam-like members that extended length-wise of the bore hole an~d engaged the bore hole surface at intervals around it. Since the apparatus of Patent No. 3,185,225 could move along the bore hole only in the drilling direction, it had to be withdrawn from the bore hole by means of a cable or the like that was supported from the surface, and consequently it was not suitable for use in drilling -~
very deep bore holes. Furthermore, the beam-like members could not be relied upon to grip the surface of a vertical bore hole securely enough to support any substantial amount of weight.

U.S. Patent No. 3,827,512 disclosed another apparatus intended to force a drilling mechanism in a feed direction, comprising two sets of claw-like anchors. When the anchors of one set engaged the bore hole surface, those of the other set were radially spaced from that surface and were moved bodily in an axial drill feeding direction relative to the engaged set. Each of the anchors was so formed and arranged that when it was engaged with a bore hole surface, the axial reaction to drilling feed force was trans-lated into a radially outward force upon the claw-like anchor, whereby the anchor tended to bite more deeply into the bore hole surface with increasing feed force.

, As one set of anchors advanced the drilling mechanism, the other set of anchors tended to be disengaged from the bore hole surface by axial force in the drill feeding direction.
Thus, the anchors could only be effective to advance the machine in the drilling direction. The patent suggested -~
that the machine could be made to back itself out of a , horizontal bore hole under its own power by means of a second apparatus, comprising another two sets of anchors, arranged back-to-back with the first one. However, this back-to-back arrangement would not have been operative in a vertical bore hole because gravity would apply a constant downward force to any set of anchors engaged with the bore hole surface to support the machine against sliding down-wardly, and once the anchors had been so engaged, there would have been no way to retract them to allow the machine to move downwardly.
The present invention solves the problem of providing a device by which a duct that extends along a deep vertical bore hole in the earth can be supported by reaction against the bore hole surface both for confinement `~ against motion relative to the bore hole and for motion in the bore hole, upwardly as well as downwardly, said device being well suited for remote control and for being powered by air in the bore hole under substantially higher pressure than air in the duct supported by the device, so that the device can be employed without the need for additional duct or hose that extends down the bore hole to it.

1~783~;9 More specifically, the present invention solves the problem of providing gripping elements or claw-like anchors in such a device that tend to bite more deeply into the bore hole surface with increasing downward force but which can nevertheless be quickly and automatically disengaged from that surface for controlled downward movement of the device.

In general, therefore, the ultimate object of the invention is to provide apparatus that ~a makes possible the drilling of extremely deep bore holes into the earth, so that geothermal energy and ~_... other resources lying very-far:beneath the.surface-.
can be utilized.

More specifically, it is an object of the invention to provide a device that is fixed to one of a plurality of endwise connected duct sections extending along a bore hole and has gripping elements which bitingly engage the side surface of the bore hole for support, which device comprises a remotely controllable pneumatic actuator for said gripping elements, with a pressure air inlet in the bore hole externally of the duct section and an exhaust air outlet communicated with the interior of the duct section, said actuator providing for actuation of the gripping elements in such a manner that, depending upon control signals received at the device, the duct section is confined against motion in the bore hole, or is moved upwardly, or is moved downwardly.

A further and still more specific object of the invention is to provide a device of the charac-ter described that is capable of being remotely con~
trolled by a relatively simple system of sound signals i !, or other radiations by which the device is selectively caused to maintain its position in a bore hole, to move downwardly along the bore hole, or to move up-wardly along it.
It is also a specific object of the invention to provide a duct supporting device of the character described wherein there are two sets of gripping elements or anchors which can be extended for bitingly gripping a bore hole surface or can be re-tracted to be clear of the bore hole surface; wherein .
the gripping elements are so formed and arrangedthat when they are engaged with a bore hole surface, a radially outward biting force that they exert against it tends to be increased by the force of gravity;
wherein one set of gripping elements is always engaged with the bore hole surface while the other set is moved axially in one direction or the other along the bore hole; and wherein simple by effective means automatically effects positive disengagement of each set of gripping elements from the bore hole surface ~:
as soon as the other set has been engaged with that surface, so that thenewly-disengaged set of gripping elements can be moved axially in either direction relative to the newly-engaged set.

Another specific object of the invention -:
is to provide a device of the character described having gripping elements that are arranged in two sets, each set being movable axially relative to the other set of gripping elements and relative to a load supported by the device, wherein an actuator for the gripping elements comprises two reciprocating drivers, each of which carries a set of gripping elements for axial motion relative to the supported load; wherein each of the drivers comprise a plurality of double- .
acting pneumatic cylinder motors; and wherein simple means are provided for constraining the several cylin-der motors that comprise each reciprocating driver to operate in unison and to constrain:the two drivers :`
always to move in opposite directions through pre-determined strokes and to begin and end their respective strokes simultaneously.
In general, the invention accomplishes these and other objectives with a device that comprises two sets of gripping elements, the gripping elements ~
; of each set being arranged to bitingly engage a bore :-hole surface under a radially outward force that in-creases with increasing axial force in one direction;
a pair of axially reciprocable, pressure fluid energized drivers, each connected between a set of gripping elements and a load to be transported along a bore hole and arranged to effect movement of the set of gripping elements relative to the load through a defined stroke in each axial direction; means connected ' ., ,,, ,',- 107836g between the drivers to constrain them always to move in opposite axial directions and to begin and end their strokes simultaneously; and a directional control device which is movable between defined limits in :
opposite directions transverse to the direction of ~ dr:iver reciprocation and which comprises two sets of : abutment members that are engaged by the gripping elements at the ends of the driver strokes and whereby .
those gripping elements that are out of engagement with the bore hole surface are forced into engagement therewith and those gripping elements that are engaged with that surface are forcefully disengaged from it, one of said two sets of abutment members being positioned ;;, for engagement by the gripping elements when the ~ 15 directional control device is at one of its said .~ defined limits and being arranged to coordinate en- -gagement and disengagement of the gripping elements for transportation of the load in one direction along the bore hole, and the other of said sets of abutment . 20 members being positioned to be engaged by the gripping :~
elements when the directional control device is at the ~, other of its limits of motion and being arranged to coordinate engagement and disengagement of the gripping : :
elements for motion in the opposite direction along the bore hole.
With these observations and objectiv:es in mind, the manner in which the inventi:on achieves its purpose will be appreciated from the following.
description and the accompanying drawings, which exemplify the invention, it being understood that changes may be made in the specific apparatus disclosed herein without departing from the essentials of the invention set forth in the appended claims.

The accompanying drawings illustrate - one complete example of an embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles there-; of, and in which:

FIG. 1 is a view in longitudinal section of a lower portion of a deeply drilled bore hole : wherein the apparatus of the present invention i8 .
being utilized for further deepening the bore hole;
, .,~
~- . ` FIG. 2a-2b is a composite view on a larger scale, partly in side elevation and partly in longitudinal section, taken at line II-II in FIG. 1 and illustrating one of the devices of this invention, but with the apparatus shown in the left-hand half of the figure (FIG. 2a) in its condition for effecting a first stage of downward movement and in the right-hand half of the figure tFIG. 2b) in its co~dition for effecting a first stage of upward movement, FIG. 2c-2d is a composite view generally similar to FIG. 2a-2b, but with the apparatus shown in the left-hand half of the figure (FIG. 2c) in its condition for a second stage of downward movement and in the right-hand half of the figure (FIG. 2d) in its condition for a second stage of upward movement;

... . . .. . ... ~ . .. .

~078369 FIG. 3 is a view of cross section taken on the plane of the line III-III in FIG. l;
FIG. 4 is a fragmentary view in longi- ~::
tudinal section taken substantially on the plane of the line IV-IV in FIG. 3;
FIG. 5 is a fragmentary view taken sub-stantially on the plane of the line V-V in FIG. 3;
J FIG. 6 is a fragmentary sectional view taken substantially on the plane of the line VI-VI in FIG. 3;
FIG. 7 is a fragmentary view in side elevation, seen in the direction denoted by the line VII-VII in FIG. 3;
FIG. 8 is a view of one of the gripping :~ :
elements shown in its relationship to portions of the device that are adjacent to it and to the side surface of a bore hole;
'is FIGS. 9 and 10 are views in cross section taken on the plane of the lines IX-IX and X-X in FIGS.
2a-2b;
FIG. 11 is a view in side elevation of that portion of the device that effects control of the direction of its movement along a bore hole;
FIGS. 12 and 13 are views in cross section, respectively taken on the plane of the line XII-XII and the plane of the line XIII-XIII in FIG. 11; and :

10783~;9 FIG. 14 is an enlarged view in longi- ;
tudinal section of one of the yielding abutment pins of the device, taken on the plane of the line XIV-XIV
in FIG. 8.

. .
, 5 Referring now to the accompanyin~ draw--, ings, and first considering FIG. 1, the numeral 1 ' denotes a portion of a bore hole which has been drilled ;, into dense, air-tight bedrock or primary formation 2 ; and which is being further deepened by means of a drill-" 10 ing mechanism that i8 not shown but is assumed to be operating ~ at a level below the bottom of the figure. Certain .,, ~-~ ; details of the apparatus=employed for deepening_the- ~ :
bore hole 1 are not shown in FIG. 1 because they do ' not relate directly to the present invention and are fully disclosed in the above-mentioned companion appli-cation, Serial No. ~ 17, to which reference may be made for further information.

In general, a duct 4 that extends through the full height of the bore hole has at its bottom a telescoping connection with the drilling mechanism whereby the drilling mechanism i8 allowed to move up and down between,defined limits relative to the duct. The upper portion of the bore hole (not shown) has an airtight lining and is provided with an air lock, so that the illustrated portion of the bore hole 1, except for the interior of the duct 4, can be pressurized wit~ pressure air from a source at the surface of the earth. The duct 4 has its upper portion projecting through the air ~078369 :.
lock and has its top end open to the atmosphere. The ~-drilling mechanism can therefore have its drill bit or drill bits driven by a pneumatic motor that has r a pressure air inlet open to the bore hole externally ~, S of the duct 4 and an exhaust air outlet communicated with the interior of that duct. Furthermore, since . the interior of the duct 4 represents a suction source relative to the pressurized air in the bore hole, ~ !~
boring debris loosened by the drilling mechanism can be sucked into the duct 4 and blown up through it to the surface by the exhaust air from the pneumatic drill ~ motor.
: The duct 4 is made up of endwise connected 'J, duct sections, certain of which can be identical plain sections 4a. However, at regular intervals along the duct it has duct sections 5 which incorporate support-ing and moving devices 3 of this invention, by which the duct is supported from the side surface 7 of the bore hole (instead of being suspended from a support at the earth's surface, as in prior apparatus), and by which the duct can be maintained stationary in the bore hole, for drilling, or can be raised or lowered for changing of drill bits. The several duct sections 4a, 5 are so connected with one another, as by means of collars 6, that individual sections can be readily attached to the upper end of the duct 4 as it is moving downwardly in the bore hole or can be taken off of it as they emerge from the bore hole when the duct is being raised. The connections between adjacent duct sections :

are of course air-tight. To facilitate handling the special duct sections 5 that incorporate the devices 3, they can be substantially shorter than the plain duct sections 4a, but their inside and outside -diameters are uniform with those of the plain duct sections and their end portions are formed for identi-cal connections with adjacent duct sections.
Referring now to FIGS. 2a-2b through 14, each of the devices 3 comprises, in general, a plurality of gripping elements 16 for engagement with the side surface 7 of the bore hole and a hereinafter described pneumatic actuator for the gripping elements that receives pressure air from the bore hole, outside the duct 4, and discharges exhaust air into the interior of the duct 4. It will be understood that the pneu-matic actuator could equally well receive its pressure air through a hose or duct extending along the bore hole and could vent its exhaust air into the bore hole, but because it cooperates nicely with a pressurized bore hole arrangement that is uniquely suited for deep drilling, it will be so described herein. It will also be understood that the duct section 5 is merely repre-sentative of any one of several types of loads that could be moved along a bore hole by means of the device 3 of this invention. The load could comprise, for example, a capsule containing measuring instruments or radioactive material to be buried. Furthermore, the device 3 is here described in relation to its use in a vertical bore hole, where the advantages of the present invention are most apparent, but it will be evident that the device 3 could be readily adapted for use in horizontal and inclined bore holes. `
The above mentioned pneumatic actuator `~l 5 comprises a plurality of double-acting pneumatic cylinder motors 10, arranged in two sets which are `, spaced from one another along the length of the duct section 5. There are preferably three pneumatic cylinder motors 10 in each set, all with their axes parallel to that of the duct section 5, and all spaced at uniform radial distances from the duct section 5 and spaced apart by uniform circumferential intervals.
~; (In FIGS. 2a-2b and 2c-2d, cylinder motors are shown, I for simplicity, as located at diametrically opposite sides of the duct section 5, but the actual preferred ~-arrangement is correctly shown elsewhere in the draw-ings). Each cylinder motor 10 comprises a cylinder 11 `~
and a piston 12 that is slideable up and down in the cylinder and has a downwardly projecting piston rod 13.
The cylinders 11 of the cylinder motors of the upper -set are secured to the duct section 5 by means of an annular plate 8 which is coaxially fastened to that duct section and to which the lower ends of said cylin-ders 11 are secured. In like manner, the cylinder motors of the lower set have the lower ends of their cylinders 11 secured to a similar annular plate 9 that is fastened to the duct section 5. Each of the secure- ~ !
ment plates 8 and 9 has an outside diameter substantially smaller than the bore hole diameter, to be well clear of the side surface of the bore hole.

107B3~9 , The gripping elements 16 are arranged : in an upper group 19 and a lower group 20. The grip-. ping elements of each group are connected with the : piston rods 13 of the upwardly adjacent set of cylin- -der motors by means of a substantially annular carry-ing plate 14 that surrounds the duct section S with some clearance and is rigidly secured to the bottom ends of the downwardly projecting piston rods. Thus the cylinder motors 10 of each set, unified by the carrying plate 14 to which their piston rods 13 are connected, comprise with that carrying plate an axially reciprocating pneumatic driver for a group 19 or 20 of gripping elements 16.
; Each such pneumatic driver can carry its group 19, 20 of gripping elements for axial motion ~ -relative to the duct section 5 through strokes defined - by the stroke limits of its pistons 12. For trans-porting the duct section 5 along the bore hole, it is necessary to so coordinate the operations of the two reciprocating drivers that each group 19, 20 of gripping elements is always moved in the direction opposite to the direction of movement of the other group, and the two drivers begin and end their strokes simultaneously. To this end, the upper and lower carrying plates 14 are connected with one another by means of three coordinating devices, located adjacent to the duct section 5 and spaced aprat at uniform circumferential intervals around it, each coordinating device comprising an endless steel cable 38 trained ..

~ i -, .
around upper and lower frrely rotatable pulleys 40 and -l 41. The upper pulley 40 (see FIGS. 2c-2d, 4 and 5) is journaled in a bearing support 42 that is fixed between the duct section 5 and a pair of motor cylin- .
ders 10, above the upper cylinder supporting plate 8. ~ ~:
` The lower pulley 41 is located a substantial distance below the upper one, in vertical alignment with it, and is freely rotatable on a suitable bearing support (not shown) that can be fixed to the duct section 5.
Thie endless cable 38 that is trained around the pulleys 40 and 41 thus has long straight stretches that extend between the pulleys, and motion of either stretch in either axial direction imparts equal but opposite motion to the other. One of those straight stretches of the cable 38 is anchored to the upper carrying plate 14 by means of a securement 39, and the other is similarly anchored to the lower carrying plate 14. The : upper cyliner supporting plate 8 has holes 43 through which the cable stretches pass, and each of the carry-ing plates 14 has similar holes 44.
Each carrying plate 14 carries at least three of the gripping elements 16. Each gripping element is supported on a bracket 15 that projects down from the underside of its carrying plate 14, directly beneath ;
one of the piston rods 13. As best seen in FIG. 8, each gripping element is somewhat elongated and is so connected with its bracket 15 as to be swingable up and down about a horizontal axis intermediate its ends and transverse to its length. The gripping elements on each carrying plate 14, and the brackets 15 that support : lQ78369 .... .
them, are spaced at uniform distances from the axis of the duct section 5 and at uniform circumferential intervals around the carrying plate. (Although FIGS. ;
2a-2b and 2c-2d show gripping elements at diametri-cally opposite sides of the duct section 5, this is for simplicity, and it is preferred that there be three gripping elements in each group, arranged as shown elsewhere in the drawings.) Each of the carrying plates 14 has an outside diameter substantially smaller than the diameter of the bore hole, to be well clear of the bore hole surface 7. However, the gripping elements 16 are so arranged that each has its length oriented radially to the duct axis, and each has an outer end portion which projects a distance beyond the outer edge of its carrying plate l~, for engagement with the bore hole surface. At its outer end, as best seen in FIGS. 8 and ll, each gripping element is formed with a biting surface 18 from which spurs project that are defined by the pointed ends of hard metal pins 17 set into the gripping element.
Note that the gripping elements 16 are so formed that their biting surfaces 18 are located below their swinging axes as well as radially out-wardly from those axes, so tha the force of gravity,acting at the connections of the gripping elements to their brackets 15, tends to exert a radially outward force component on the outer ends of the gripping elements by which they are urged into more secure . .

- 1C~78369 biting engagement with the bore hole surface 7.
Attention is also directed to the fact that the outer ends of the gripping elements, at which their biting ; surfaces 18 are located, are biased downwardly, so that when those biting surfaces are disengaged from a bore hole surface the o~uter ends of the gripping elements swing downwardly and away from the bore hole surface and thus tend to remain clear of that surface.
As shown, such downward bias is imposed upon the gripping elements by gravity inasmuch as their outer end portions are heavier than their inner end portions.

It will-be generally apparent at this -point that during the coordinated operation of the reciprocating drivers comprised of the pneumatic motor6 10, the duct section 5 can be moved either upwardly or downwardly in the bore hole by causing the gripping elements of each group 19 and 20 to engage and dis-engage the bore hole surface 7 in proper coordination with the strokeæ of the drivers. The means for effect-ing properly timed and properly c(oordinated engagement of gripping elements with the bore hole surface and disengagement of gripping elements from that surface comprises a directional control device which i8 generally designated 21 and which is best seen in FI~S.
11-13. There is, in fact, a directional control device 21 for each group 19, 20 of gripping elements, but, as explained hereinafter, the two directional control - devices are coordinated to act as one.

Each directional control device (they are identical) comprises an upper annular rotatable plate 22, a lower annular rotatable plate 23 and a plurality of spacers or tie rods 24 that hole the S rotatable plates 22 and 23 in fixed axially spaced relatlon to one another and constrain them to rotate in unison. (For simplicity, the spacers 24 are not shown in FIGS. 2a-2b and 2c-2d but are shown in FIGS. 11-13.) The annular plates 22 and 23 are coaxial with the duct section 5 and, by suitable supporting and bearing means (not shown), they are confined -to rotation through a predetermined angle. The upper rotatable plate 22 directly underlies its adjacent cylinder supporting plate 8 or 9 and is thus located lS above the annular carrying plate 14 for its group l9 or 20 of gripping elements 16; whereas the lower rotational plate 23 is located a distance below that carrying plate. The vertical distance between the rotatable plates 22 and 23 is sufficient to allow the carrying plate 14 to move between them through the full stroke of the pistons 12. To allow the spacers 24 to extend through the carrying plate 14 and to move with rotation of plates 22 and 23, the plate 14 has short arcuate slots 25 (see FIGS. 9 and 10) through which the spacers 24 freely pass. And, since each rotatable plate 22 is located between a cylinder supporting plate 8 or 9 and a carrying plate 14, each rotatable plate 22 has arcuate slots 33 through which the piston rods 13 freely pass, as best seen in FIG. 12. As may also ~ " ~
~7836g be seen in FIG. 12, the upper rotatable plate 22 has further arcuate slots 44a through which pass the straight stretches of the endle~s driver coordinating cables 38.

5Each rotatable directional control device 21 provides for downward motion of the duct section 5 when it is at one limit of its rotation, designated N in FIGS. 9, 10, 12 and 13; and at its `other limit of rotation, designated by U in tho~e figures, it provides for upward movement of the duct.
At each limit of its rotation the directional control device brings certain of a plurality of abutment pins `~
~ 26, 27, 34, 35 into alignment with the gripping ele-- ments 16 on the gripping element carrier plate 14 that is between its rotatable plates 22, 23; and as the gripping elements, carried by the piston rods 13, are moved upwardly or downwardly relative to the directional control device, the gripping elements engage the abut-ment pins that are aligned with them and, by such en-gagement, are swung into or out of engagement with the - bore hole surface 7, as circum~tances require. The specific manner in which this takes place for each direction of duct movement will appear from the follow-ing explanation.

On the underside of the upper rotatable plate 22 there are two groups 26, 27 of downwardly projecting abutment pins, in an arrangement best seen in FI~. 12. The abutment pin~ of one group, designated ~78369 by 26, are rigid and are so located radially and cir- -~
cumferentially on the rotatable plate 22 that when that plate is in its N (downward) position of rotation, illustrated in FIG. 9, each of the abutment pins 26 can be engaged by the outer end portion of a gripping element 16 therebeneath. Such engagement occurs during upward movement of the carrying plate 14, `
near the top of its stroke, and causes the outer end of the gripping element to swing downwardly, away from engagement with the bore hole surface 7, as can be seen in the lower part of FIG. 2a and the upper part of FIG. 2c. To enable the abutment pins 26 to clear the carrying plate 14 on which the gripping elements 16 are mounted, the carrying plate has arcuate lS recesses or bays 36 in its outer edge, in the neighbor-hood of the respective gripping elements, as best seen in FIGS. 9 and 10. Of course the abutment pins of the group 26 are clear of the gripping elements when the directional control device is in its U position.

The downwardly projecting abutment pins 27 of the other group on the rotatable plate 22 are so positioned radially and axially on that plate that they are at all times clear of the gripping elements when the plate 22 is in its N position; but when it is in its U (upward) position of rotation, illustrated in FIG. 10, each of those pins 27 can be engaged by a radially inner portion of one of the gripping ele-ments 16 therebeneath. Such engagement of course occurs as the carrying plate 14 nears the top of its . 1~78369 upward stroke, and the carrying plate has arcuate ;~
slots 37 through which the pins 27 can freely pass for this engagement. As the inner end portion of each gripping element is thus swung downwardly, its outer end is swung upwardly into engagement with the bore hole surface 7, as illustrated in the lower ; portion of FIG. 2b and the upper portion of FIG. 2d.
Since the gripping element engages the bore hole surface 7 at a more or less indefinite point in its swing, and continued force should there-i after be applied to it to urge it into secure engage-ment with the surface 7 while the driver completes its upward stroke, the abutment pins 27 are yieldable upwardly against resilient bias. Specifically, as shown in FIG. 14, each of the abutment pins 27 com-prises an upper telescoping member 29 that is fixed ; at its upper end to the rotatable plate 22 and a lower telescoping member 28 that is axially slideable , on the lower portion of the upper telescoping member.
~; 20 Each of the telescoping members 28, 29 has a well ;~ that opens axially into the well in the other so that, . .
together, those two members define a housing in which a coiled expansion spring 30 is confined. The spring 30, by reacting against the closed ends of the tele-scoping members, biases the lower telescoping member 28 downwardly. A pin 32, secured in the tubular wall .
of the lower telescoping member and projecting radially inwardly from it, rides in an axially extending slot - . :: :: :;. .: . : . ~ - . ~

31 in the tubular wall of the upper tele6coping member 29 and engages the bottom of that slot to define a lower limit of spring biased motion of the lower member 28.

The abutment pins 34~ 35 on each directional control device 21 project upwardly from its lower rotatable plate 23 and, as best seen in FIG. 13, are arranged somewhat similarly to the upper abutment pins 26, 27 but are engaged by the under-sides ~f the gripping elements 1~ as the carrying plate 14 approaches the end of its downward stroke.
Specificallyj when the directional--~ontrol--device -21 =-.
is in its U (upward) position of rotation, one of the abutment pins 34 can engage the underside of each ; 15 gripping element at a location thereon that is spaced radially inwardly from its swinging axis, to thus swing the outer end of the gripping element down-wardly away from engagement with the bore hole surface 7, as illustrated in the upper portion of FIG. 2b and the lower portion of-FIG. 2d. ~en the direc-tional control device 21 is in its N (downward) position of rotation, the abutment pins 35 align with the respective gripping elements and, as the carrying plate 14 nears the end of its downward stroke, the under&ide of each of its gripping elements is en- -gaged by one of those abutment pins, outwardly of its swinging axis. This causes the outer end of each gripping element to swing upwardly and into engagement with the bore hole surface 7, as illustrated in the _ 27 -1C~78369 upper part of FIG. 2a and the lower part of FIG. 2c.
Again, since the engagement of a gripping element against the bore hole surface occurs at a somewhat ; indeterminate point in its swing, and requires con-tinued application of bias to the gripping ele~ent through the remainder of the driver stroke, the abutment pins 35 are axially yieldable and are : essentially identical in construction to the abut-ment pins 27.

It will be observed that when the I
directional control device 21 is in its N (downward) position, the grippin~ elements are engaged near their outer ends by the rigid downwardly projecting abutment pins 26 on the upper rotatable plate 22 and by the yielding upwardly projecting abutment pins 35 on the lower rotatable plate 23; and when the directional device 21 is in its U position, the gripping elements are engaged near their inner ends by the yielding abutment pins 27 on the upper ro-tatable plate 22 and by the rigid abutment pins 34 on the lower rotatable plate 23.

As mentioned above, the outer end of each gripping element is biased to swing downwardly.
However, when the gripping element is disengaged from the bore hole surface, its downward swing in.
response to such bias is limited, to enable the abutment pins to cooperate with it, and it remains in an attitude defined by engagement of its inner end against the underside of the carrying plate 14, .

~ 1078369 as may be seen from the lower part of FIG. 2a and the upper part of FIG. 2c.
As indicated above, the rotational position N or U of the directional control device for the upper set 19 of gripping elements is always the same as that of the corresponding device 21 for the lower set 20 of gripping elements. In general, each of the upper and lower directional control : .
devices 21 has its own pneumatic actuator 45 for rotating it to its N and U positions, but the actua-tors for the two devices 21 are connected to a single four-way valve 53 by which they are both controlled and which thus coordinates them.
FIGS. 3 and 6 show details of the ; 15 actuator 45 for the upper directional control device . 21, but the one for the lower directional control device is identical to it. Thus, each such actuator comprises a small double-acting cylinder motor that overlies the cylinder supporting plate 8 or 9 ~` 20 immediately above its directional control device and :~, has its cylinder 46 swingably secured to that support-: ing plate by means of a trunnion 47 that projects upwardly from the supporting plate. The piston rod 48 of the cylinder motor 45 has its outer end swing-ably connected to a trunnion 49 which is fixed to the upper rotatable abutment pin plate 22 and pro-jects upwardly through an arcuate slot 50 in the cylinder supporting plate 8. Air ducts 51, 52 lead from opposite ends of each cylinder 46 to the four-way . . . ...... . .. . .

10783~;9 valve 53. Details of the valve 53 are not shown because it is essentially identical with a four-way valve 54 that is described hereinafter. However, it will be un~erstood that the valve 53 has two positions, in one of which it causes the cylinder motors 45 to swing the directional control devices to their N positions and in the other of which said motors are caused to swing said devices to their U positions. The position of the valve 53 is remotely controllable from the surface of the earth, as explained hereinafter. The valve 53 can _ be located on the duct section,5, above the sup-porting plate 8, and can have a pressure air inlet opening to the bore hole externally of the duct 4 and an exhaust air outlet communicated with the interior of the duct section 5.

The second four-way valve 54, illus-trated in FIGS. 2a-2b, 2c-2d, 3 and 7, controls the operation of the cylinder motors 10 that actuate the gripping element6 16. The control valve 54 can also be located on the duct section 5, above the cylinder supporting plate 8, and can have a pressure air inlet 60 that opens to the bore hole externally of the duct 4 and an exhaust outlet 63 that is com-municated with the interior of the duct section 5 through a remotely controllable shut-off valve 64.
The pressure air inlet 60 is preferably provided with a suitable water separator and oil mist lubricator 61.

iO783~i9 -~ -The four-way valve 54 comprises a housing 55 that has four ports 59, 62, 65, 65a in its cylindrical side wall, at the top, bottom and sides thereof. A drum 56 that is rotatable inside the housing has two right angle passages 57, 58 that can be aligned with the housing ports in either of two positions of rotation of the drum. As shown, the top housing port 59 is connected with the pressure air inlet 60, and the bottom housing port 62 is connected with the exhaust air outlet 63 that leads to the interior of the duct section 5. The left ; hand housing port 65 is connected ~ith a duct 66 from which first branch passages 67 extend to the lower (rod) ends of the cylinders 11 for the upper set 19 of gripping elements. The duct 66 extends down beyond the first branch passages 67 and communicates with second branch passages 68 that open to the upper - ends of the cylinders 11 for the lower set 20 of ; gripping elements. The right-hand port 65a of the four-way valve 54 is connected with a second duct 69 which has a first set of branch passages 70 that connect with the upper ends of the upper cylinders 11 and a second set of branch passages 71 that connect with the lower ends of the lower set of cylinders 11.
It will be apparent that when the exhaust air outlet 63 is blocked by the remotely con-trollable shut-off valve 64, the cylinder motors 10 can not operate. The shut-off valve is normally biased to such a blocking condition, but it opens ...

107~3~9 .
upon receipt of a signal from the surface and remains open aæ long as it continues to receive that signal.
As explained hereinafter, the signal can be a sound tone of a predetermined frequency, and the shut-off valve comprises apparatus which detects and responds to sound of that frequency, such apparatus being known and therefore not lllustrated.
.
So long as the shut-off valve 64 i8 : in an open condition, the cylinder motors 10 remain - . 10 in operation, automat~cally reversing their direction of motion at the end of each stroke by reason of .
an automatic shifting of the rotational position of the drum 56 of the four-way control valve 54.
Such automatic shifting is effected by a lost motion connection between the cylinder motors 11 and the control valve drum 56, comprising, as best seen in FIG. 7, an axially yielding toggle member 72, extend-ing more or less horizontally and connected with the .:;
~ drum 56, and a vertical rod 77 which has its lower ; 20 end connected to the upper gripping element carrying plate 14 and which has lengthwise sp~ced apart abut-ment dogs 80, 81 that alternately engage the toggle member 72 to actuate it as the rod 77 is carrIed up and down by the carrying plate 14 to which it is attached. The toggle member comprises a pair of telescoping elements? one of which i~ a spring chamber 73 that provides for lengthwise extension and con-traction of the toggle link and biases it towards its extended condition. At one end, the toggle link .~ - 32 _ is pivotally connected to a pin 74 which is eccen-trically secured in the valve drum 56 and extends parallel to the drum axis. The other end of the link is pivotally secured to a stationary bearing support 75 that is fixed to the cylinder of one of the motors 10 (see FIG. 3). The medial portion of the link is formed as a ring 76 through which the vertical rod 77 extends for its lengthwise up and down motion. The upper and lower surfaces of the ring portion 76 serve as abutments against which the dogs 81 and 80 can respectively engage. Thus, as the pistons 12 of the upper set of cylinder motors approach the end of an upward stroke, the lower dog -80 on the rod 77 engages the underside of the toggle link,, swinging that link upward and thereby shift-ing the valve drum 56 from its angular position F
shown in FIG. 7, through 90 to its alternate position M, in which it connects the upper cylinder motors 10 for a downward piston stroke. At the end of a down-ward stroke, the upper dog 81 on the rod 77 engagesthe upper side of the toggle link, swinging it down and thus shifting the valve drum through 90 back to its F position at which the upper set of motors is again connected for an upward stroke.
Thus, as long as the cut-off valve 64 remains open, the cylinder motors 10 will remain in operation, the upper motors always moving oppositely to the lower ones, and all of the motors always being , .

reversed simultaneously at the end of each stroke.
The direction in which the device will move along the bore hole as a result of such operation of the motors, whether upwardly or downwardly, will depend upon the rotational position of the directional control device 21, as governed by its four-way control valve 53.
From the foregoing explanation concerning the motor control valve 54, it will be apparent that the four-way valve 53 can be biased to one of its positions (e.g., the N position for downward movement of the device 3) and can be actuated to its other position by any suitable remote control apparatus, as for example a small pneumatic servo (not shown) controlled by a signal-responsive shut-off valve (not shown), so that the absence of a directional control signal will cause the device 3 to move downward as long as it receives a "move" command signal of one frequency ;~ -and to move upwardly if receipt of that "move" signal is accompanied by receipt of an "up" signal of another frequency.
It may be noted at this point that the drilling mechanism can be similarly controlled, being stopped when no signal is received by it and caused to operate as long as it receives a continuous "drill"
command signal of a third frequency.
An automatic "move" command signal generator at the bottom of the duct 4 can be arranged .
to begin emission of a "move" signal whenever the , ,~, :

' .

.: , .

10783~;9 `
telescoping connection between the duct and the drill-ing mechanism is fully extended, and to terminate that signal when the telescoping connection is fully contracted. The duct is thus caused to move down automatically when and as necessary to keep up with downward progress of the drilling mechanism. -The duct 4 can serve to carry all command signals to all of the devices 3 and to the drilling mechanism. Inasmuch as sound waves are propagated through a steel structure at a velocity of about 5,300 m/sec., the several devicés 3 along the length of the duct 4 can thus be operated substantially in unison. To the extent that the devices 3 are not started and stopped exactly simultaneously, owing to differences in the time when they receive signals traveling along the duct, a certain amount of cushionirgis provided by the elasticity of air in the opposite end portions of the m-otor cylinders ll. Because of this same -cushioning, an extremely long duct, weighing hundreds of tons, can be supported from the side surface of a bore hole by devices 3 at regular intervals along its length. Each device along the duct supports only a part of the total weight of the duct, by every device supports its proportionate share of that weight.
For a complete understanding of the -,~ operation of the device 3, let it be assumed that the device is stationary, with its lower group 20 of , gripping elements engaged with a bore hole surface ~ i :~ , 1~78369 and with the pistons 12 of the cylinder motors at positions intermediate the ends of their strokes.
The control valve 54 is assumed to be in its position illustrated in FIG. 2c-2d, and the shut-off valve ~ ;
64 is closed. Therefore the duct rests on a cushion of air trapped above the pistons 12 of the lower ~ cylinders.
; If, now, a "move" signal is received, not accompanied by an "up" signal, the shut-off valve 64 opens, releasing the air trapped in the upper ends of the lower cylinders and the lower ends of the upper cylinders. The cushion of air disappears, and, instead, the trapped air flows to the low-pressure interior of the duct section 5, as the lower cylinders - 15 11 move down relative to their pistons 12 and the upper pistons move downward in their cylinders 11.
; By such piston movement, the duct section 5 is lowered ; relative to the carrying plate 14 for the engaged lower group 20 of gripping elements, and the carrying plate 14 with the disengaged upper group 19 of gripping elements is moved down relative to the bore hole as well as relative to the duct section 5. The relative movements between the cylinders and pistons of the two sets of air motors are synchronized by the endless cables 38 and are aided by flow of pressure air into the lower ends of the lower cylinders and the upper ends of the upper cylinders.
Since no "up" signal was received, the directional control devices 21 are in their N (downward) 107~3~9 positions, in which the upper rigid abutment pins 26 and the lower resilient abutment pins 35 are aligned with the gripping elements.
As the carrying plate 14 that carries the upper group 19 of gripping elements reaches the end of its downward stroke, those gripping elements, -as shown in FIG. 2a, are brought into engagement with the upwardly projecting yielding abutment pins 35 of the upper directional control device and are t hereby swung out into engagement with the bore hole surface. Very soon thereafter, the gripping elements of the lower group 20 are disengaged from the bore hole surface by downwardly projecting rigid abutment pins 26 of the lower directional control device, which pins are brought down upon the outer end of those gripping elements as the cylinders 11 of the lower air motors are in the final part of their downward movement. The position of the drum 56 of the four-way control valve 54 is shifted near the end of the stroke just described, and the apparatus is thus in the condition shown in FIG. 2a-2b when that stroke is ended.
Now pressure air flows into the bottom of the upper cylinders and the tops of the lower `~ 25 cylinders, while exhaust air flows out of the upper ends of the upper cylinders and the lower ends of the bottom cylinders. The cylinders 11 of the upper ;~
:` motors, and with them the duct section 5, therefore descend relative to the engaged upper group 19 of .::
, ,, ,.~.

10~7l33~9 gripping elements, as indicated by the large arrow ~`
N in FIG. 2a; and at the same time the group 20 of lower gripping elements, which are out of engage-ment with the bore hole surface, move down with the lower pistons 12 relative to the duct 5 and relative to the bore hole surface. As this stroke ends, the gripping elements of the lower group 20 engage :
the upwardly projecting yielding abutment pins 35 of the lower directional control device and are swung into engagement with the bore wall surface, while the rigid downwardly projecting abutment pins ;~
26 of the upper directional control device come down onto the gripping elements of the upper group 19 and drive them downwardly out of engagement with the bore hole surface. At the same time, the position of the four-way valve is again shifted, to feed pressure air to the upper ends of the upper cylinders and the lower ends of the lower cylinders, and to vent the lower ends of the upper cylinders and upper ends of the lower cylinders, for the beginning of a new cycle, with the condition of the apparatus being as shown in FIG. 2c. Such operation of the r ; device continues until the "move" signal terminates and the shut-off valve 64 is thereby closed.
,.... 25 During downward movement, the air being exhausted from the contracting cylinder ends to the interior of the duct section 5 is not vented unre-strictedly but is instead released slowly enough so that descent of the duct section is controlled or ..

107~33~;9 braked. Since the carrying plates 14 of the two drivers are tied together by means of the endless ~ `
cable 38, the "idle" driver (having its gripping `
elements disengaged) cooperates in producing -this braking or cushioning of descent.
If an "up" signal is received by the device 3 along with a "move" signal, the directional control devices 21 shift to their U positions, in which upper yielding abutment pins 27 and lower rigid abutment pins 34 align with the gripping elements.
It is now assumed that the two drivers are intermediate the ends of their strokes, the upper gripping elements 19 are engaged with the bore hole surface, and the valve 54 is in its condition illustrated in FIG.
2c-2d. Upon opening of the shut-off valve 64, pressure air from the bore hole forces its way into the upper portion of the upper cylinders 11, lifting those cylinders (and with them the duct section 5) relative to the engaged gripping elements 19. Pressure air also forces its way to the undersides of the pistons 12 of the lower cylinders, raising those pistons ~ relative to the bore hole surface as well as relative ; to the duct section S and thus raising the disengaged `
.., l;i . gripping elements of the lower group 20. Meanwhile, air is vented to the interior of the duct section 5 from the lower portion of the upper cylinders and ` the upper portion of the lower cylinders. As this ~, stroke is ending, the lower grippingelements 20 are ~ raised into engagement with the bore hole surface ,~"' '~:
~ 39 ~

1C~783~9 by the lower downwardly projecting resilient abutment pins 27, and immediately thereafter the upper upwardly projecting rigid abutment pins 34, which are moving upwardly with the rotatable plate 23 and the duct ; 5 section 5, engage the upper gripping elements 19 to release them from the bo~e hole surface. At the end of this stroke the drum of the four-way valve 54 is shifted, and the apparatus i8 now in the con-dition illu~trated in FIG. 2b.

Pressure air now flows into the upper ends of the lower cylinders 11, so that those cylin-ders are raised, and with them the duct 5. -~ Pre~8ure --air also flows into the lower ends of the upper cylinders, thus raising their pistons 12 and conse-quently lifting the disengaged upper gripping elements 19 relative to the duct section 5 as well as relative `~ to the bore hole surface. Near the end of this stroke, the upper gripping elements 19 are carried into en-gagement with the upper downwardly projecting yield-able abutment pins 27 and are thus swung into biting engagement with the bore hole surface. Immediately ~`~ afterward, the lower rotatable plate 23, carried by the upwardly moving duct section 5, brings its rigid, , upwardly projecting abutment pins 34 into engagement with the lower gripping elements 20, swinging them away from the bore hole surface. As this stroke ends, the four-way control valve is again reset for a new stroke in the opposite direction, and thereupon the apparatus is in the condition shown in FI~. 2d and the cycle i8 repeated.

1(:1 78369 In the upper portion of a bore hole the air is likely to be very humid, whereas at depths in excess of 6,000 meter~ the air has relatively low humidity by reason of being heated to temperatures S of 300-450C. It will be apparent that the apparatus of this invention is adapted for operation under these extreme environmental conditions.

Those skilled in the art will appre-. ciate that the invention can be embodied in forms other~than as herein disclo~ed for purposes of illus-tration. - ~
_ . J
The invention is defined by the follow-ing claims:

,, .

,' .

'x t.
', ' .

:., ....
.;, ::

Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A device whereby a load such as a duct section, having an axis that can substantially coincide with a bore hole axis, can be supported from the side surface of a bore hole, and whereby said load can be alternatively and selectively confined against motion in response to a force that urges it axially in one direction or can be moved along the bore hole in said one direction or in the opposite axial direction, said device comprising:
A. two groups of gripping elements, each gripping element (1) having an outer end portion which can bitingly engage a bore hole surface and (2) being mounted for limited swinging about a swinging axis which is transverse to said load axis, by which swinging said outer end portion is carried in a surface-engaging direction, obliquely away from the load axis and in said opposite axial direction, and in an opposite surface-disengaging direction, (3) each of said gripping elements being biased in its surface-disengaging direction;
B. a pair of reciprocable drivers, one for each group of gripping elements, said drivers and their respective groups of gripping elements being spaced from one another along the load axis and each of said drivers being connected between its group of gripping elements and the Claim 1 - Continued load and arranged to move its group of gripping elements relative to the load through defined strokes in opposite axial directions;
C. coordinating means connected to both of said reciprocable drivers to constrain them to synchronized motion wherein each driver carries its group of gripping elements in the axial direction opposite to that in which the other group of gripping elements is being carried and the two drivers simultaneously begin and end their respective strokes; and D. a directional control device movable in directions substantially transverse to the load axis between a pair of defined positions, said directional control device comprising two groups of abutment members that are formed and arranged for engagement with the gripping elements near the ends of their strokes, to swing gripping elements that are out of engagement with the bore hole surface in their surface-engaging direction and to swing gripping elements that are engaged with said surface in their surface-disengaging direction, (1) one of said groups of abutment members being arranged for engagement of the gripping elements when the directional control device is in one of its said
1. Claim 1 - Concluded positions and effecting such engagement and disengagement between the gripping elements and the bore hole surface as enables the drivers to move the load in said one axial direction, and (2) the other of said groups of abutment members being arranged for engagement of the gripping elements when the directional control device is in the other of its said positions and effecting such engagement and disengagement between the gripping elements and the bore hole surface as enables the drivers to move the load in said opposite axial direction.
2. 2. The device of claim 1, further characterized by:
   E. a control device which so controls energization of the drivers as to determine the prevailing direction of their strokes and which comprises a member movable in opposite directions between a pair of defined limits that respectively correspond to the respective stroke directions of one of the drivers; and F. means providing a lost motion connection between said one driver and said member of the control device, whereby said driver shifts said member from one of its said limits to the other as said driver reaches the end of each of its strokes, to enable the driver to be energized for an immediately following stroke in the opposite direction.
3. 3. The device of claim 2 wherein each of said drivers comprises a double acting pneumatic cylinder motor and wherein said control device comprises a four-way valve having a pressure air inlet connection, an exhaust air outlet connection, and a pair of connections to the cylinder of each cylinder motor, further characterized by:
   G. a normally closed shut-off valve connected with said exhaust air outlet connection to normally block flow of return air from the cylinders and thus prevent operation of the drivers but which can be opened to cause the drivers to operate.