US3329405A

US3329405A - Earth borehole drilling rigs

Info

Publication number: US3329405A
Application number: US600424A
Authority: US
Inventors: Fanshawe Hew Dalrymple; Stevenson William David
Original assignee: FNRD Ltd
Current assignee: FNRD Ltd
Priority date: 1963-11-25
Filing date: 1966-12-09
Publication date: 1967-07-04
Anticipated expiration: 1984-07-04
Also published as: GB1110562A

Description

July 4, 1967 FANSHAWE ET AL 3,329,4U5

EARTH BOREHOLE DRILLING R165 '7 Sheets-Sheet 1 Filed Dec. 9, 1966 INVENTOEJ' H D. FANSPIAWE W. D. ETEVENSON gmnmaw wwfl *Wm TTOR/YEYS July 4, 1967 D A WE ET AL 3,329,495

EARTH BOREHOLE DRILLING Mes mvmmes H .D. FANsmWE W. D. STEVENSON Gi name, Wm //ZZan A TTOENEZI;

y 1967 H. D. FANSHAWE ET AL 3,329,405

EARTH BORE HOLE DRILLING RIGS Filed Dec. 9, 1966 '7 Sheets-Sheet 5 tit:

mmzvmles H. D. FANSHAWE W. D. STEVENSON y 4, 1967 H. D. FANSHAWE ET AL 3,329,405

EARTH BOREHOLE DRILLING FIGS Filed Dec. 9, 1966 7 Sheets-Sheet 4 I Q g k TU Q i ii' i! w W gr W1 11v VENTQQ; H D. FAN SI-LAWE W D. STEVENSON A TTOMEYJ July 4, 1967 H FAN$HAWE ET AL 3,329,405

EARTH BOREHOLE DRILLING RIGS 7 Sheets-Sheet 6 Filed Dec. 9, 1966 Mm A Hw Y W y 1967 H. D. FANSHAWE ET AL 3,329,405

EARTH BOREHOLE DRILLING RIGS Filed Dec. 9, 1966 7 Sheets-Sheet V &T

q an w i a Q H.D.FANSHAW W D. STEVENSON A TTGE/VEKS' United States Patent 3,329,405 EARTH BOREHOLE DRILLING RIGS Hew Dalrymple Fanshawe and William David Stevenson, Edinburgh, Scotland, assignors to F.N.R.D. Limited, London, England, a British company Filed Dec. 9, 1966, Ser. No. 600,424 Claims priority, application Great Britain, Nov. 25, 1963, 46,526/63 19 Claims. (Cl. 254106) ABSTRACT OF THE DISCLOSURE Drill-pipe transfer arrangement for borehole drilling rig having reciprocating hand-over lifts for running and pulling the drill-pipe. Interacting pivotal arms on respective lifts provide alternative support from one lift or the other. Includes feedand WithdraW rnechanism for removable pipe joint-engaging suspension sleeve for the drillstring.

This application is a continuation-in-pa-rt of our application Ser. No. 413,529, filed Nov. 24, 1964, now aband-oned.

The invention relates to earth borehole drilling rigs and especially to rigs in which the operation of pulling the drill pipe string is performed by means of a system comprising two or more lifts from one to the other of which the support of the pipe string is arranged to be passed, to permit of at least individual pipes being made ready to be broken from the string for removal in lengths in succession until the drilling bit may be changed. The greater the dept-h of the borehole, the longer the time taken for the whole operation of dismantling the pipestring, removal and replacement of the drilling bit and remaking the pipe-string for further drilling; if this time can be reduced then the overall drilling time to the full depth of the borehole can also be very much reduced.

The present invention is directed towards producing an improved form of transfer device for use in transferring the support of the pipe-string from one lift to another and a further object is to enable automatic control of the pulling operation to be carried out smoothly.

In accordance with the invention, in a transfer mean-s for passing a load from one support to another and which includes collar means engaging the load, the two said supports each incorporates a set of pivot support members, the members of each set being arranged to pivot to co-operate with said collar means sequentially, separately and in combination in sets, so as to transfer the weight of said load from the one set to the other set. Preferably said collar means is split so as to engage and disengage said load as required and said pivot support members are arranged to act in sets, or separately, to engage the parts of the collar means to retain them in their loadengaging attitudes while the load is being supported thereby.

Preferably said collar means is adapted to engage cooperating parts of the load, and when the load comprises a drill pipe-string, the collar means may engage the joint members which co-operate with successive pipes to form the drill-string. Where two lifts are arranged to co-opcrate in pulling the pipe-string, the movement of the lift-s will be arranged to be substantially reciprocal so that the pipe-string may be raised first by the lower lift While the upper lift move-s down to a transfer position in juxtaposition to the transfer position of the lower lift; and when these positions are reached transfer takes place in the manner stated above, the upper lift thereupon continuing to raise the pipe-string while the lower lift returns to a lower position where its pivot support mem- 3,329,405 Patented July 4, 1967 "ice bers may be pivoted to engage another section of the pipestring to take the load ready for the sequence to be repeated. In that case it is preferred that the pivot support members in each set shall engage the said collar means at substantially the same level and preferably substantially symmetrically in respect to each other. To enable this to be brought about, the pivots for these support members may be carried on extensions from the said lifts, extending upwards in the case of the lower lift and downwards in the case of the upper lift.

In order to provide for maximum clearance between the pipe-string and the support members when the latter are pivoted away from the string, so as to enable the lifts to move relative to the string on their return movements, and at the same time to maintain a compact construction, the support members are preferably arranged so as to assume a load engaging position wherein the line of the resultant re-actional thrust at the load engaging surfaces of each member shall pass substantially through its pivotal axis. Furthermore, the engaging surfaces of the support members and the collar means are preferably shaped to ensure an adequate area of contact, and to ensure that any tendency of the pivot-carrying extensions from each lift to strain under. the load results in movement of the support members with the load to compensate for that strain so as to maintain support of the load. It may be necessary, or desirable, to provide frictional pad members as the load engaging surfaces of the support members to increase the grip of the support members on the collar means; and it has been found that by this means the angle between said line of reactional thrust through the pivot of a support member, when supporting the load, and the horizontal may be as little as 18".

In order that the invention may be more clearly understood, one embodiment thereof will now be described way of example with reference to an application to aborehole drilling rig incorporating mutually interacting, reciprocating lifts, whereby the drill-pipe-string may be pulled or run; by arranging for the suspension of the pipestring to be transferred from one lift to the other, pulling or running can be made substantially continuous and one such arrangement is described with reference to FIG- URES 15, 16, 17, 17A-17D, 18, 18A and 18B of US. patent specification No. 3,194,313. In that arrangement the two lifts are arranged to reciprocate one above the other between limiting positions in which the upper lift is at an upper limit of travel and the lower lift is at a lower limit and an intermediate position where both lifts are in juxtaposition; when pulling, a pipejoint is arranged to be engaged by means on the lower lift near its lower limit and the pipestring is suspended thereby from the lower lift while being pulled towards the intermediate position, where the weight of the suspended pipe-string is transferred to the upper lift. The upper lift then pulls the joint, and the pipe-string with it, to a higher position while the lower lift returns to its lower position. By arranging that the ditference in height between the upper and lower limits approximates to a pipe length, it can be seen that the arrangement is capable of continuously pulling the pipe-string.

The present invention is particularly useful in connection with such a drilling rig and in the accompanying drawings:

FIGURE 1 is a plan view of one form of transfer means embodying the invention for transferring part of a pipe-string from one lift to the other in such a rig;

FIGURE 2 is a sectional view of the transfer means of FIGURE 1, taken on the line XX in FIGURE 1;

FIGURE 3 is a somewhat diagrammatic view of a reciprocating lift arrangement incorporating the transfer means of FIGURES 1 and 2;

FIGURES 4 and are, respectively, a half-plan view, partially in section and a combined plan view of a lift supported mechanism for use in presenting part of the suspension means for the pipe-string or, alternatively, for withdrawing said suspension means from the pipe-string;

FIGURE 6 is a side view, partially in section, of the mechanism of FIGURES 4 and 5, looking from the right in FIGURE 5 and indicating relative positions of the transfer means on the two lifts; and

FIGURES 7(a) to 7(2) are diagrams illustrating the sequence of operations of a system for drilling, pulling or running of the drill-pipe-st-ring of an earth borehole drilling rig, using the mechanisms of the constructions illustrated in FIGURES 1, 2, 4 and 5.

Referring now to FIGURES 1 and 2, collar means in the form of a sleeve 1 is provided to embrace -a joint 2 between successive pipe lengths of the string. The sleeve is in two halves, split on the line 3-3 and hinged at a point 4 so as to permit of application to or withdrawal from the pipe joint.

The sleeve is formed internally to grip the pipe joint and externally is provided with

projections

5 and 6 symmetrically disposed about the line 3-3. These projections have surfaces 7 and 7', profiled as indicated in the case of 7'. Pivoted support members 8 and 8' are provided and these members engage with surfaces 7 and 7' respectively when the members are pivoted into their supporting positions; the surfaces 7, 7' are part-cylinders with centres which, in the position of engagement by the support members, are at the axes of

pivots

9 and 9 respectively of the support members. The positions taken by the support members 8 and 8', when these are not required for supporting the sleeve, are indicated in broken lines for member 8' in FIGURE 2.

Pivots

9 and 9 respectively are supported on extensions 10, 10' (one of which is shown in FIGURE 2) from the lower lift.

The

projections

5 and 6 are formed also with pairs of

profiled surfaces

11 and 11; these are symmetrically spaced about the surfaces 7 and 7' respectively and each is similarly profiled to the surfaces 7 and 7' and they are part-cylinders with centres which, in the position of engagement by

pivoted support members

12 or 12, are at the axes of pivots 13 and 13' respectively of these support members. The hinges 13 and 13' are carried on extensions 14, 14', depending from the upper lift. The positions of these

support members

12, 12, when retracted from their support positions, are indicated in broken lines for member 12 in FIGURE 2.

Friction pads, such as are indicated at 15 and 16 in FIG- UREZ, may be secured to, or formed at, the ends of the

support members

8, 8' and 12, 12', these pads being shaped to provide profiles mating with the

surfaces

7, 7' and 11, 11.

As will be observed, if there is a tendency for the extension supports 10, 10' or 14, 14 to strain under the weight of the pipe-string supported by the

members

8, 8' or 12, 12, there wil be a tendency for the pressure on the sleeve to relax, and for the pipe-string to tend to move downwards under gravity. However, adhesion of the

friction pads

15 and 16 to the

support surfaces

7, 7 or 11, 11', and the shaping of the profiles of these surfaces, ensure that the support members 8, 8'-or 12, 12' pivot about their hinges until their respective positions of equilibrium are reached. The structure will be designed to be such as to be rigid enough to prevent excessive straining 0f the supports so that such further pivotal movement of the

support members

8, 8' or 12, 12', is never likely to be appreciable, except possibly in an emergency, such as the occurrence of a jolt due to snagging of the pipe-string; but even this can be resisted in the same way.

In order to relieve the

hinges

9, 9' and 13, 13' of part of the load, the support members are provided with

thrust blocks

17, 17' and 18, 18' respectively.

When in their retracted positions, the

support members

8, 8' and 12, 12, as the case may be, are arranged to be 4 sufficiently clear of projections *5 and 6 for the sleeve member 1 to be opened up about its pivot 4 and to be moved from the drill-pipe joint engaging position to a withdrawn position, as indicated in broken lines at 1 in FIGURE 1.

In accordance with another aspect of the invention means are provided to elfect presentation and withdrawal of the sleeve to or from a pipe-string joint during a pulling or drilling operation, said means comprising a base member carrying, on one side, slide means for transfer movement of the sleeve member, .said slide means being provided with cam means for pivotal movement of the hinged parts of the sleeve member, said slide means and said cam means preferably being arranged to be actuated by separate operating means.

In a preferred construction, the operating means for actuating said slide means incorporates hydraulic ram members and it is also preferred that the operating means for actuating the cam means incorporates hydraulic ram means.

In the case described above of the drilling rig with cooperating lifts, one of these presentation/ withdrawal means will need to be carried on each lift. However, in order to avoid interference during an operation of transfer of the load from one lift to the other, the mounting arrangement of such means on the lifts will probably need to be of a nature such as to enable the lower transfer means to be moved out of the way of the upper transfer means.

One embodiment of presentation/ withdrawal mechanism for the sleeve in accordance with the invention will now be described by way of example with reference to FIGURES 4, 5 and 6 of the accompanying drawings.

In these figures, the parts of the sleeve member and of the pivotal support members for engaging the sleeve member are indicated by the same reference numerals as in FIGURES 1 and 2.

The presentation/withdrawal mechanism is supported on a plate 20, which has a pair of U-shaped track members 21 fixed thereto, and adapted to guide an operating device comprising two parallel fiat plate members 22 carried at each end by slides 23, which engage track members 21. In FIGURE 5 the device is shown for convenience in two parts, one being in the fully withdrawn position and the other in the fully extended position, and parts attached thereto are similarly shown in their respective limiting positions. FIGURE 6 likewise shows the parts in two limiting positions, but whereas the top plate 20 is shown in FIGURE 6 together with the uppermost parts of the mechanism, these are omitted from FIGURE 5 for clarity.

The supporting sleeve 1 is of split construction, the two halves 1' and 1 being pivoted at 4 (4"in the extended position) and a circumferential groove 25 is provided to accept a pair of

gripping jaws

26, 27 which can support the sleeve. These jaws are pivoted at 28, 29 to the plate members 22 and are biased by tension springs 30, 31 to a position in which they grip the sleeve.

Levers

32, 33 are keyed to the

respective pivots

28 and 29 and these levers are biased by the

springs

30, 31 against

surfaces

34, 35 on the edges of

plates

36, 37 respectively. These

plates

36, 37 are slidably clamped to the main plate 20 by means of

spacer plates

38, 39 and pairs of

plates

40, 41 which are secured to the

plates

36, 37 by bolts, such as indicated at 42, 43 and 42', 43. The latter pairs of bolts have centre portions arranged to slide in

slots

44, 45 respectively, formed in plate 20, when the

plates

36, 37 are moved by means of the links 46 (46) and 47 (47) between pivots 48 and 49 on the operating member 50 and pivots 51 (51) and 52 (52') on the plate units themselves. Clearance slots 53 (53') and 54 (54) are provided in the main plate 20 to permit of such movement. Operating member 50 is actuated by the spindle 55 extending from an hydraulic cylinder 56 to which operation fluid is arranged to be fed to move the spindle in one direction or the other to open or close the

plates

36, 37.

The

plates

36, 37 serve to engage extensions 57, 57' on the respective halves (1', 1") of the supporting sleeve. These extensions, in effect, hook themselves to the plates, and are prevented from becoming unhooked by reason of abutment against a central slide 58. The end of this slide is rounded to provide the slight clearance necessary for the

jaws

26, 27 to carry the parts 1' and 1" into the fully closed position in which these parts meet to embrace a drill-pipe section.

Movement of the plate members 22 towards and away from the line of the drill-string is effected by means of a pair of

hydraulic rams

59 and 60, each of which is pivoted at one end of the plate members and at the other to the main plate 20.

The sequence of movements of the various parts of the gear will be described as from the positions which they occupy in the state represented by the lower half of FIG- URE 5.

In that position the weight of the drill-string is taken by the members 8 (8') or 12 (12') of another similar arrangement above or below that illustrated so that the support members 8 (8) or 12 (12') of the latter may be pivoted clear of the sleeve.

The

plates

36, 37 are then opened by action of the spindle 55 and links 46 (46') and 47 (47'), the movement of the

plates causing levers

32, 33 to swing the

jaws

26, 27 about the

pivots

28, 29 and away from the centre line of the pipe-string. If it is desired to leave the sleeve in string-engaging position. then one set or the other of the support members 8 (8) and 12 (12) should be moved into position to take the full weight of the drillstring. The

jaws

26, 27 will then swing clear of the sleeve so that they may be retracted with the plate members 22. On the other hand, if it is desired to remove the sleeve from its joint-engaging position, then the support members 8 (8') or 12 (12') remain pivoted clear of the sleeve or are moved to that position and the two halves of the sleeve pivot open to clear the pipe joint and are retracted with the jaws. Catch members 61 (61') are provided on the sleeves to give a friction clamping effect to retain the jaws and sleeve parts in engagement with the sleeve parts while the latter are being moved in or out of position.

Referring now to FIGURES 3, 6 and 7(a) to 7(e) the two lift supports of an oil drilling rig, such as is described in columns 22.26 of US. patent specification No. 3,194,313 are indicated as A and B. The pipe-string in FIGURES 7(a) to 7(a) is shown as a single line and these figures illustrate the sequence of operations as the pipestring is being pulled. The lift supports are each operated in reciprocating motion, for example by hydraulic jack systems, between an intermediate position in which they are in juxtaposition and either a limiting upper or a limiting lower position, :as indicated. The joint for securing one drill-pipe to a second is indicated at C and that for joining the second to a third at C. The V-shaped members D, D represent the split sleeves as described above with reference to FIGURES 1 and 2 for engaging the pipestring to transfer the weight thereof to one or the other of the lift supports.

In order to control engagement or withdrawal of a sleeve at the appropriate time, a plate means 20 as shown in FIGURES 4-6, together with the appropriate gripping mechanism and withdrawing or engaging mechanism, is provided in association with each lift.

In FIGURE 6, an indication is given of the position of the plate 20 for the sleeve transfer mechanism for the upper lift A relative to the underside of the lift. FIGURE 6 is also used to illustrate the relative positions of the lower lift B and its plate 20 for the sleeve transfer mechanism associated with lift B, but in the case of the lower lift, the plate 20 and the transfer mechanism is not actually in the position shown when the lifts are in juxtaposition. The support 62 for supporting the upper transfer mechanism on the upper lift and the support 63 for supporting the lower transfer mechanism on the lift B are arranged to swivel away from the line of the pipe-string at certain points of the pulling (or running) programme so as to enable these mechanisms to perform further manipulations of the sleeves. The lower lift transfer mechanism may therefore be moved to a displaced position, thereby enabling the transfer mechanisms to travel with their respective lifts and still enable the lifts to move into juxtaposition; the upper transfer mechanism has, however, to be moved into the position indicated in FIGURE 6 to avoid interference between the two transfer mechanisms at this stage.

Referring now to FIGURES 7(a)7(e), a sequence of movements of the different mechanisms will now be explained.

In FIGURE 7(a), the pipe-string is shown as being supported by the lift A (through the associated sleeve D), the lift A moving upwardly while lift B moves down, the latter taking with it another sleeve D' in a displaced and stowed position. In FIGURE 7(b) the two lifts are near their upper and lower limits respectively and the mechanism on lift B is moved from its displaced position to the position where it may place sleeve D into engagement with the pipe-joint C. The lower transfer mechanism is thereupon again moved to its displaced position. Support members 8, 8' are moved into position to engage sleeve D' and the weight of the pipe-string is taken by lift B as the latter moves upwardly and lift A moves downwardly, support members 12, 12' being retracted; the transfer mechanism on the upper lift having been moved into posi tion, withdraws the sleeve D as shown in FIGURE 7(a) and moves to its displaced position again.

FIGURE 7(d) shows the lift B moving upwards to continue the pulling of the pipe-string, upper lift A moving downwards carrying the sleeve means D (the drill-pipe above joint C having been dismantled from the string). The upper transfer means applies the sleeve D to a temporary store in the displaced position and returns to the ready position for removal of the other sleeve as the next pipe-joint reaches the upper station of lift A. The lower transfer means is moved into its displaced position and stays there during the next stage, as shown in FIGURE 7 (e) where the lifts are in juxtaposition. At this stage, lift B moves the pipe-string with the sleeve D high enough for the

support members

12, 12 on lift A to be moved into position to engage the sleeve D. At the same time the lower transfer means engages the sleeve D and withdraws it from its store on the upper lift, which latter then commences its upward travel; the weight of the drill-string is taken from the

support members

8, 8 by the support members 12, 12' and the pipe-joint C proceeds upwards with the lift A. Support members 8, 8' are moved into their retracted positions as the lift B moves downwards. The next stage is that indicated in FIGURE 7(a) but with the sleeves D and D interchanged.

Thus it is seen that the whole of the pipe-string may be pulled automatically by circulation of the sleeves D and D' round a path. As an alternative to transfer of the sleeves from one to the other lift by rotation of the plates 20 at the withdrawn position, the sleeves could be transferred by suitable means directly from a point near the upper limit of the upper lift to a point near the lower limit of travel of the lower lift, as will be evident to those skilled in the art. This would, however, involve additional mechanism and probably would not be so convenient.

It will be clear that the pulling operation may be a little more complicated at its very commencement in view of the fact that the pipe-string may at that stage be connected to the power swivel at the end of a stage of the drilling operation. Since this complication will not affect the understanding of the present invention and since it is considered that details of this part of the pulling operation will be evident to those skilled in the art, specific details are not included in this description. It is pointed out, however, that the disclosure in the aforesaid U.S. patent specification No. 3,194,313 is helpful on this point.

It will also be clear that the operation of running the pipe-string is very similar, but in reverse, to that of pulling.

We claim:

1. Transfer means for passing a suspended load from one moving support to another moving support, comprising means for moving said supports into and out of juxtaposition with each other, collar means adapted to engage the load for suspension thereof, means for engaging said collar means with said suspended load, first weight-bearing means carried by one of said supports, second weightbearing means carried by the other of said supports, means for moving each of said first and sec-nd weight-bearing means into and out of engagement with said collar means, said'first and second Weight-bearing means in the juxtaposed state of said supports being engageable with different parts of said collar means simultaneously, said transfer means being adapted so that said supports may be moved towards each other with the load moving on the first support while being suspended from said collar means engaged by said first weight-bearing means and so that in the juxtaposed state ,of the supports the second weightbearing means may be moved into engagement with the ,collar means and the weight of the load transferred to the second weight-bearing means, said first weight-bearing means being thereupon moved out of engagement with said collar means, so that the supports may be again separated with the load moving on said second support while being suspended from said collar means engaged by said second weight-bearing means.

2. Transfer means as claimed in claim 1, wherein each of said first and second weight-bearing means comprises a set of pivoted weight-bearing members, said weightbearing members being pivotable into and out of engagement .with said collar means when said supports are in juxtaposition, the set of weight-bearing members of one of said weight-bearing means being symmetrically arranged with respect to engagement of said collar means and with respect to the weight-bearing members of the other set.

3. Transfer means as claimed in claim 1, wherein each of said first and second weight-bearing means comprises a set of pivoted weight-bearing members pivotable to engage or disengagesaid collar means, the two sets of said members being arranged to be substantially symmetrical with respect to each other and to the collar means when in the engagement/ disengagement position.

4. Transfer means as claimed in claim 3, wherein said collar means is split into a plurality of parts for ease of engageability with the load, and the pivoted weight-bearing members on either support are adapted to engage the parts of the collar means to urge them into engagement with the load when supporting the latter.

5. Transfer means as claimed in claim 3, wherein said collar means is shaped to conform to the shape of parts associated with the load.

6. An earth borehole drilling rig arrangement comprising an upper reciprocating lift support and a lower reciprocating lift support, weight-bearing means carried by each of said lift supports, collar means adapted to engage joints of a drill-string for the rig, means for bringing said collar means int-o and out of engagement with a joint, means for moving each of said weight-bearing means into and out of engagement with said collar means so that the weight of the drill-string is supported by said collar means through the respective weight-bearing means, means for moving said lift supports to bring them into and out of juxtaposition during their reciprocating motions and said upper and lower weight-bearing means in the juxtaposed state of said lift supports being engageable with different parts of said collar means simultaneously, whereby said lift supports may be moved towards each other with the drill-string moving on the one support while being suspended from said collar means engaged by the respective weight-bearing means and in the juxtaposed state of the supports the other weight-bearing means may be moved into engagement with collar means and the weight of the drill-string transferred to this other weight-bearing means, said one weight-bearing means being thereupon moved out of engagement with said collar means so that the supports may be again separated with the drill-string moving on the other support while being separated from the said collar means engaged by the other weight-bearing means.

7. An earth borehole drilling rig arrangement as claimed in claim 6, wherein the weight-bearing means on each lift support is arranged to engage said collar means at substantially the same level when the two lift supports are in juxtaposition for transference of the weight of the drillstring.

8. An earth borehole drilling rig arrangement as claimed in claim 7,, in which the weight-bearing means associated with each lift support comprises a set of pivoted weightbearing members pivotable to engage or disengage said collar means, and extensions from said lift supports carry the pivots for said weight-bearing members, said extensions extending upwards in the case of the lower lift support and downwards in the case of the upper lift support.

9. An earth borehole drilling rig arrangement as claimed in claim 6, wherein the weight-bearing means on each said lift support comprises a set of pivoted weight-bearing members pivotable to engage or disengage said collar means, said weight-bearing members being so arranged that, when in load engaging position, the line of reactional thrust at the load engaging surface of each member passes substantially through its pivotal axis.

10. An earth borehole drilling rig arrangement as claimed in claim 6, wherein the engaging surfaces of said weight-bearing means and said collar means are shaped to ensure an extensive area of mutual contact.

11. An earth borehole drilling rig arrangement as claimed in claim 8, wherein the engaging surfaces of said weight-bearing means and said collar means are shaped to ensure that any tendency of said pivot-carrying extensions to strain under the weight of the drill-string results in movement of the weight-bearing members with the drillstring to compensate for the strain so as to maintain the support of the drill-string.

12. An earth borehole drilling rig arrangement as claimed in claim 6, wherein the surfaces of said weightbearing means engageable with said collar means include frictional pad members. 13. An earth borehole drilling rig arrangement comprisng an upper reciprocating lift support, a lower reciprocatmg lift support, weight-bearing means carried by each of said lift supports, each of said weight-bearing means being adapted to bear the weight of a drill-string for the rig, said lift supports being reciprocable into and out of juxtaposition with each other, at least two collar means each adapted to engage the drill-string and each having different parts engageable by said upper and lower weight-bearing means whereby said lift supports may be moved towards each other with the drill-string moving on the one support while being suspended from said collar means engaged by the respective weight-bearing means and in the juxtaposed state of the supports the other weight-bearing means may be moved into engagement with collar means and the weight of the drill-string transferred to this other weightbearing means, said one weight-bearing means being thereupon moved out of engagement with said collar means so that the supports may be again separated with the drillstring moving on the other support while being separated from the said collar means engaged by the other weightbearing means and manipulating means for said collar means on each of said lift supports, said manipulating means being operable to move said collar means into engagement with the drill-string before engagement of said weight-bearing means with said collar means and out of engagement with the drill-string after disengagement of said weight-bearing means with said collar means.

14. An earth borehole drilling rig arrangement as claimed in claim 13, including means for moving the disengaged collar means on one lift support to a position Where it can be moved into engagement with the drillstring by the manipulating means on the other lift support.

15. An earth borehole drilling rig arrangement as claimed in claim 14, including means for moving said disengaged collar means from one lift support into a corresponding disengaged position on the other lift support.

16. An earth borehole drilling rig arrangement as claimed in claim 13 in Which each of said collar means is of hinged, split form, and said manipulating means comprises a base member and slide means carried on one side of said base member for producing transfer movement of said collar means, said slide means including cam means for producing pivotal movement of the hinged parts of said collar means.

17. An earth borehole drilling rig arrangement as claimed in claim 16, including separate operating means for actuating said slide means and said cam means.

18. An earth borehole drilling rig arrangement as claimed in claim 17, wherein the operating means for actuating said slide means includes hydraulic ram members.

19. An earth borehole drilling rig arrangment as claimed in claim 17, wherein the operating means for actuating said cam means includes hydraulic ram means.

References Cited UNITED STATES PATENTS 3,194,313 7/1965 Fanshawe 166-775 OTHELL M. SIMPSON, Primary Examiner.

Claims

1. TRANSFER MEANS FOR PASSING A SUSPENDED LOAD FROM ONE MOVING SUPPORT TO ANOTHER MOVING SUPPORT, COMPRISING MEANS FOR MOVING SAID SUPPORTS INTO AND OUT JUXTAPOSITION WITH EACH OTHER, COLLAR MEANS ADAPTED TO ENGAGE THE LOAD FOR SUSPENSION THEREOF, MEANS FOR ENGAGING SAID COLLAR MEANS WITH SAID SUSPENDED LOAD, FIRST WEIGHT-BEARING MEANS CARRIED BY ONE OF SAID SUPPORTS, SECOND WEIGHTBEARING MEANS CARRIED BY THE OTHER OF SAID SUPPORTS, MEANS FOR MOVING EACH OF SAID FIRST AND SECOND WEIGHT-BEARING MEANS INTO AND OUT OF ENGAGEMENT WITH SAID COLLAR MEANS, SAID FIRST AND SECOND WEIGHT-BEARING MEANS IN THE JUXTAPOSED STATE OF SAID SUPPORTS BEING ENGAGEABLE WITH DIFFERENT PARTS OF SAID COLLAR MEANS SIMULTANEOUSLY, SAID TRANSFER MEANS BEING ADAPTED SO THAT SAID SUPPORTS MAY BE MOVED TOWARDS EACH OTHER WITH THE LOAD MOVING ON THE FIRST SUPPORT WHILE BEING SUSPENDED FROM SAID COLLAR MEANS ENGAGED BY SAID FIRST WEIGHT-BEARING MEANS AND SO THAT IN THE JUXTAPOSED STATE OF THE SUPPORTS THE SECOND WEIGHTBEARING MEANS MAY BE MOVED INTO ENGAGEMENT WITH THE COLLAR MEANS AND THE WEIGHT OF THE LOAD TRANSFERRED TO THE SECOND WEIGHT-BEARING MEANS, SAID FIRST WEIGHT-BEARING MEANS BEING THEREUPON MOVED OUT OF ENGAGEMENT WITH SAID COLLAR MEANS, SO THAT THE SUPPORTS MAY BE AGAIN SEPARATED WITH THE LOAD MOVING ON SAID SECOND SUPPORT WHILE BEING SUSPENDED FROM SAID COLLAR MEANS ENGAGED BY SAID SECOND WEIGHT-BEARING MEANS.