US3610675A

US3610675A - Releasing device for the locking mechanism in wire line core drills

Info

Publication number: US3610675A
Application number: US835965A
Authority: US
Inventors: Oyvind Jensen
Original assignee: Atlas Copco AB
Current assignee: Craelius AB
Priority date: 1968-07-02
Filing date: 1969-06-24
Publication date: 1971-10-05
Anticipated expiration: 1988-10-05
Also published as: DE1933481A1; FR2014486A1; SE320942B; DE1933481B2; GB1248863A

Abstract

This invention relates to a releasing device for disconnecting a locking mechanism for a catching device which serves for connecting the wire with the inner core tube in wire line core drills, the locking mechanism having a gripper head connected with the wire, the gripper head being provided with a locking shoulder to engage with a latch, a releasing sleeve being provided to release the locking shoulder by applying a predetermined pulling force to the wire.

Description

References Cited UNITED STATES PATENTS United States Patent [72] Inventor Oyvind Jensen Stockholm Sv, Sweden [21] Appl. No. 835,965

[22] Filed June 24,1969 [45] Patented Oct. 5, 1971 [73] Assignee Atlas Copco Aktiebolag Nacka, Sweden July 2, 1968 Sweden [32] Priority [54] RELEASING DEVICE FOR THE LOCKING MECHANISM IN WIRE LINE CORE DRILLS 2 Claims, 10 Drawing Figs.

[51] Int Cl 294/86.19, 294/862 ....E2lb3l/00, E21c 19/00 FIG. 3A

0 352 7 2 3 44M J0 4 Md 3 i SHEET 1 BF 3 ll lltll- PATENIEU [1m 519m FIG. 7

RELEASING DEVICE FOR THE LOCKING MECHANISM IN WIRE LINE CORE DRILLS The present invention relates to a releasing device for disconnecting a locking mechanism for a catching device which serves for connecting the wire with the inner core tube in wire line core drills thereby enabling lifting and also lowering of the inner core tube, the locking mechanism having a gripper head connected with the wire, the gripper head being provided with a locking shoulder behind which a latch connected with the inner core tube is intended to engage and lock in order to perform said connection.

In lifting the inner core tube in wire line core drills a catching device is used which is lowered down in the borehole and being intended to engage a gripper means on the upper end of the inner tube. However, it may occur that the inner tube for some reason jams in the outer tube, and once when the catching device has engaged the gripper means there is not any possibility of releasing the catching device without lifting the entire bore tube. Besides the wire has then to be cut off since it otherwise hinders the disassembling of the lifted bore tubes.

The object of this invention is to provide a device which enables the catching device to be released from locking engagement also in cases when the inner tube jams in the outer tube and, thus, cannot be picked up. Thus, at least the catching device and the wire can be picked up, whereupon other steps must be taken to continue the work.

The releasing device according to the invention is substantially characterized by a releasing sleeve which in its normal rest position is brought back a distance from the locking shoulder of the gripper head to release the locking shoulder, the releasing sleeve being retainable in this position by means of a positioning mechanism which is releasable by applying a predetermined pulling force to the wire, said pulling force having a direction from the inner core tube and exceeding the weight of the inner core tube. Upon releasing of the positioning mechanism the sleeve is provided to be displaced unobstructedly towards the gripper head and to engage the locking shoulder of the gripper head, thereby moving away the latch.

The present invention will now be described in more detail, by way of example, with reference to the accompanying drawings. Like references refer to like or similar parts throughout the drawings. In all embodiments shown and described the tubes and housings may be joined by screw threading.

FIG. I is a cross-sectional view of an embodiment of the releasing device in accordance with the invention, illustrating particularly a gripper head and locking means.

FIGS. 2A, 2B and 2C are illustrating the operational sequence for releasing the sliding sleeve from a locked position (with active locking means) to a free position.

FIGS. 3A and 3B are illustrating the manner in which the locking means shown in FIGS. 1 and 2 is disengaged from the gripper head when the sleeve is brought to engagement with the locking shoulder of the gripper head.

FIGS. 4A, 4B and 4C are illustrating the manner in which the inner core tube with the locking means is lowered by the gripper head, as well as the manner in which the gripper head is released and lifted.

FIG. 5 is a cross-sectional view of a second embodiment of the invention, illustrating particularly a modified positioning mechanism.

Referring to FIG. 1, the illustrated releasing device is primarily intended for use in conjunction with a catching device consisting of two main parts, viz a latch I rotatable on a shaft pivot 7 and provided with a locking and gripping shoulder 14, and a gripper head 2 with a gripper shoulder 20, a gripper head rod 23 attached to said gripper head 2, and a dis placeable releasing sleeve 12. The lowermost end of the sleeve 12 is provided with a flange 17, the upper edge of which is bevelled. The uppermost end of the sleeve 12 is provided with

recesses

15 and 16 for accommodating a screw 8.

The sliding sleeve is intended to be brought to a rest position, i.e. the sleeve is brought back from the gripping shoulder 2a, and to be positioned in this position by rotating the sleeve to the right and upwards, as seen on. the drawing, against the forces of a torsion spring 13 and a compression spring 19, so that the screw 8 is accommodated in the recess 16. The locked rest position is illustrated in FIG. 2A. In the free position, illustrated in FIG. 2C, the sleeve can be displaced from its upper rest position, as is shown in FIG. 3A, the screw 8 being accommodated in the recess 15, to a lower position as is shown in FIG. 3B, the flange 17 thereby engaging the locking shoulder 20 of the gripper head.

When it is desirable to pick up the :inner core tube owing to the bottoming of the core samplewhich is detected on the surface by a manometer (not shown) which indicates an increase flushing water pressure-the gripper head 2 is brought down through the bore tube 11, the releasing sleeve 12' thereby being fixed in its rest position in accordance with FIGS. 2A and 3A. The gripper head slides over the bevelled locking shoulder 14 of the locking means 1, the locking means thereby in this case simultaneously rotates on the pivot 7 so that a lower shoulder 9 disengages the recess 10 of the outer tube 5. In order to enable the head 2 to more easily move away the shoulder 14 a weight 18 of massive steel is provided in the bottom end of the wire. The inner tube can now be lifted since the head 2 engages the shoulder 2a beneath the shoulder 14.

However, it may occur that the inner tube for some reason has jammed in the outer tube so that it is impossible to lift the inner tube in this manner. For enabling at least the very gripper head and the wire to be lifted a biased compression spring 19 is provided, such as a package of cup springs, so that the screw 8 can be pulled away out of its locking engagement with the recess 16 (shown in FIGS. 2A, 2B and 2C) when the pulling force on the wire exceeds a predetermined value. The sliding sleeve 12 thereby rotates clockwise a quarter of a turn by the action of the torsion spring 13, the sleeve simultaneously falling against the upper surface of the shoulder 14. By removing the pulling force on the wire and by means of the force exerted by the weight 18 one can get the flange 17 of the sliding sleeveto slide over the shoulder 14 so that the flange gets the position shown in FIG. 3A. As is shown the upper portion of the sliding sleeve thereby rests on the housing 4 of the locking means. When the wire is again stretched the flange 17 will be positioned over the head 2, and since its upper edge is bevelled the flange 17 as well as the head 2 will easily slide past the shoulder 14, thereby enabling the lifting, such is illustrated in FIG. 3B.

Boreholes of the present type are usually filled with water, and in order to bring the inner core tube downwards in the borehole one simply lets the core tube sink downwards in the hole, the water giving the desired damping of the velocity of fall. However, if the borehole is drained, the inner core tube must be lowered, and in that case the releasing device in accordance with the invention can advantageously also be used.

Thus, when a new inner tube shall be lowered the sliding sleeve is in its nonlocked position, and the operational sequence is then in accordance with FIGS. 4A, 4B and 4C. In lowering the tube the gripper head 2 with the shoulder 2a hence is in engagement with the bottom surface of the shoulder 14. Upon the bottoming of the inner tube the gripper head 2 is further lowered a little so that the sleeve 12 is engaging the upper edge of the housing 4, the position of which is adapted in such a manner that also the flange 17 has now slid over the shoulder 14. If the wire is new again stretched the flange 17 as well as the head 2-as is explained in conjunction with FIGS. 3A and 3B-will slide upwards over the shoulder 17 because of the bevelling of the flange. The locking means I thereby swings on the pivot 7 owing to the pressure of a wire spring 3. and the shoulder 9 engages the recess 10 and thus hinders any upwards movement of the inner tube during the boring operation. I

FIG. 5 illustrates a second embodiment in which the positioning mechanism consists of an O-ring 20 lying in a comparatively deep groove 21 in the releasing sleeve 12, the O ring cooperating with a shallow groove 24 in the housing 25 in the rest position of the releasing sleeve. On a pulling force on the wire exceeding the weight of the inner core tube the sleeve 12 gets loose and sinks downwards towards the shoulder 2a in substantially the same manner as in the embodiment shown in FIGS. 1-4. For enabling the O-ring 20 to be replaced in the housing 25 without being damaged a tapering 22 is provided in the housing 25.

The invention is not limited to the embodiments shown and described but covers any other embodiment within the scope of the claims.

I claim:

1. A releasing device for releasing a locking mechanism in a catching device which is intended to connect the wire with the inner core tube in wire line core drills in order to enable lifting and also lowering of the inner core tube, the locking mechanism having a gripper head connected with the wire, the gripper head being provided with a locking shoulder behind which a latch connected with the inner core tube is intended to engage and lock to perform said connection, characterized by a releasing sleeve which in its normal rest position is brought back a distance from the locking shoulder of the gripper head to release the locking shoulder, the releasing sleeve being retainable in this position by means of a positioning mechanism which is releasable by applying a predetermined pulling force to the wire, said pulling force having a direction away from the inner core tube and exceeding the weight of the inner core tube, the releasing sleeve upon such releasing of the positioning mechanism being provided to be displaced unobstructedly towards the gripper head and to engage the locking shoulder of the gripper head, thereby moving away the latch and said positioning mechanism including a torsion spring, one end of which is fastened to a gripper head rod attached to the gripper head, the releasing sleeve being slidably mounted on said rod, and the other end of which is fastened to the releasing sleeve, the upper end edge of the releasing spring is provided with a locking recess in which a positioning means attached to the gripper head rod is intended to be accommodated for the positioning of the releasing sleeve after same in its brought back position is rotated to provide the desired biasing of the torsion spring, an axially active compression spring is provided on the gripper head rod in order to retain the positioning means in fixed position in the recess and to give way for enabling the removal of the positioning means from the recess and thereby to unbias the torsion spring upon a wire pulling force which is directed away from the inner core tube and which substantially exceeds the weight of the inner core tube.

2. A releasing device for releasing a locking mechanism in a catching device which is intended to connect the wire with the inner core tube in wire line core drills in order to enable lifting and also lowering of the inner core tube, the locking mechanism having a gripper head connected with the wire, the gripper head being provided with a locking shoulder behind which a latch connected with the inner core tube is intended to engage and lock to perform said connection, characterized by a releasing sleeve which in its normal rest position is brought back a distance from the locking shoulder of the gripper head to release the locking shoulder, the releasing sleeve being retainable in this position by means of a positioning mechanism which is releasable by applying a predetermined pulling force to the wire, said pulling force having a direction away from the inner core tube and exceeding the weight of the inner core tube, the releasing sleeve upon such releasing of the positioning mechanism being provided to be displaced unobstructedly towards the gripper head and to engage the locking shoulder of the gripper head, thereby moving away the latch and said positioning mechanism including an O-ring provided in a groove in the releasing sleeve and positioned in an inactive position by engagement in a shallow groove in a housing in which the wire is fastened, said O-ring giving way to enable the displacing of the sleeve towards the shoulder of the gripper head upon a certain wire pulling force which is directed away from the inner core tube and which substantially exceeds the weight of the inner core tube.

In colu myi 3 lin'e 3 7 the word" "spring" should Signed andse aled'this'zevth day of May 1973.

(SEAL) ROBERT GOTTSCHALK Commissioner of Paten Attest z EDWARD M.FLETCHE1R,JR. Attesting Officer