GB2122237A

GB2122237A - Drill rod guide

Info

Publication number: GB2122237A
Application number: GB08310899A
Authority: GB
Inventors: Ossi Paivalainen
Original assignee: Tampella Oy AB
Current assignee: Tampella Oy AB
Priority date: 1982-05-17
Filing date: 1983-04-21
Publication date: 1984-01-11
Also published as: SE8302729L; JPS58207476A; SU1268107A3; FR2526852A1; FI66053C; DE3317592A1; IT1163369B; DE3317592C2; GB2122237B; FI66053B; JPS6229595B2; FI821737A0; NO831745L; ZA832869B; AU1423683A; FI821737A7; IT8321097A0; CH661562A5; GB8310899D0; SE8302729D0

Abstract

A drill rod guide for a drilling machine, comprising a frame (1), two jaws (2, 3) displaceably supported in the frame between open and closed positions by means of supporting arms (4, 5, 8), connecting means for connecting the supporting arms to each other so that the jaws are displaced in opposite directions when they are opened and closed, and at least one actuating means (11, 12, 13) for displacing the supporting arms of the jaws. The connecting means comprise transmission wheels (21, 22) mounted in the frame and engaging the supporting arms of the jaws so that the displacement of one of the jaws with respect to the frame causes a displacement of the same extent of the other jaw in the opposite direction with respect to the frame. The actuating means acts at least on the supporting arm or supporting arms of one of the jaws. The centre between the jaws is fixedly positioned with respect to the frame in spite of the displacements of the jaws. <IMAGE>

Description

SPECIFICATION Drill rod guide for a drilling machine The present invention relates to a drill rod guide for a drilling machine comprising a frame, two jaws displaceably supported by the frame by means of supporting arms and forming gaps for the drill rod, connecting means for connecting the supporting arms to each other so that the jaws are displaced in opposite directions when the gaps are opened and closed, and at least one actuating means for displacing the jaws.

In drilling operations using sectional drill rods guides qf this type are commonly used for coupling and discoupling of the individual drill rods (drill bars and drilling pipes). The guides lock a sleeve between the drill rods stationary and serve as a drill guide during drilling. The presently commonly used retaining guides do not centre the drill rod into the drilling center and are constructionally complicated because they comprise a plurality of bearings and joints subjected to wear and are heavy compared with their locking force.

The Swedish Patent Specification 21 51 54 discloses a guide in which both supporting arms of one of the jaws are slideably mounted in a frame and are connected to the piston rod of a pressure fluid cylinder fastened to the other jaw so that both jaws are displaceable towards and away from each other. The pressure fluid cylinder is displaceable between two extreme position abutments provided in the frame. The jaws centre the drill rod only when the cylinder engages one of the extreme position abutments as the jaws are closed because the unit formed by the jaws, the supporting arms and the pressure fluid cylinder is displaceable with respect to the frame in the intermediate positions of the jaws.

The Swedish Printed Specification 391769 describes a guide comprising two jaws mounted in a frame displaceably towards and away from each other along a guideway. The jaws are connected to a pressure fluid cylinder through a connecting rod mounted by means of a ball joint to each jaw and through rocking arms mounted in the frame. The jaws do not automatically centre the drill rod because the jaws are displaceable in the same direction with respect to the frame.

The Finnish Patent Specification 41 525 and the German Printed Specification 1 232 091 describe guides comprising two jaws mounted slideably in a frame and each provided with pressure fluid cylinders of their own connected to a common supply channel system for pressure fluid. The jaws do not automatically centre the drill rod because one of the jaws is displaceable without the other jaw being correspondingly displaced in the opposite direction.

The object of the present invention is to provide a guide which eliminates the above mentioned disadvantages and permits a reliable centering of the drill rod into the drilling centre.

This object is achieved by means of a guide according to the invention which is characterized in that the connecting means comprise transmission wheels mounted in the frame and engaging the supporting arms for the jaws, so that the movement of one of the jaws with respect to the frame causes a movement of the same extent in the opposite direction of the other jaw with respect to the frame, and at least one of the jaws is subjected to the action of the actuating means.

The invention is based on the idea of positively controlling the movements of the jaws so that the movement of one of the jaws with respect to the frame always causes a movement of the same extent of the other jaw with respect to the frame but in the opposite direction. This can be realized by means of a simple gear mechanism in which the intermediate wheels mounted in the frame ensure a forced movement of the jaws. A reliable centering of the drill rod into the drilling centre is obtained by means of the guide. The guide is light-weight with respect to its locking force and does not comprise any joints subjected to wear because the jaws and their supporting arms carry out a linear movement only. The guide is flat and very short in the drilling direction which shortens the overall length of the feeding device.

The invention will be described in more detail in the following with reference to the accompanying drawing in which Figures 1 and 2 are schematic side and end views, respectively, of the operating principle of a guide according to the invention, Figure 3 is an end view, partially in section, on an enlarged scale of the detailed construction of the guide illustrated in Figures 1 and 2, Figure 4 is a side view of the guide, Figure 5 is a section along line V-V in Figure 3, and Figures 6 to 10 illustrate alternative embodiments of the guide.

Figures 1 and 2 of the drawings illustrate a preferred embodiment of a guide according to the invention. The guide 0 is mounted stationarily at the end of a feeding beam S of a drilling apparatus along which beam the drilling machine driving the drill rod is displaceable during drilling.

The guide 0 comprises a plate-like frame 1 and two jaws 2 and 3 displaceable with respect to each other and provided with slot-like gaps 2a, 3a (Fig. 3) by means of which the jaws engage a drill rod sleeve during coupling and discoupling of the drill rod and center the drill rod into the drilling centre during drilling.

One of the jaws 2 is fastened to two parallel cylindrical supporting arms 4, 5 which are slideably mounted in corresponding bores 6, 7 in the frame. The other jaw 3 is similarly fastened to a cylindrical supporting arm 8 which is slideably mounted in a corresponding bore 9 in the frame.

In addition, the frame is provided with guide surfaces 10 guiding the jaw and preventing the supporting arm 8 from rotating in the bore 9.

The supporting arm 8 for the jaw 3 is fastened to a piston rod 11 which forms an axial extension thereof. The piston 12 of said piston rod is displaceable in a cylinder 13 in the frame. The cylinder is closed by a cover 1 4. The reference numerals 1 5 and 16 denote connecting means for supplying pressure fluid into and out from the cylinder depending on the direction of movement of the piston. The connecting means are connected by conduits to a pressure fluid source through a control valve by means of which the pressurized fluid is optionally directed to either side of the piston.

The supporting arms are provided with teeth facing each other. Each supporting arm 4, 5 of the jaw 2 is provided with teeth 1 7 and 18, respectively, and the supporting arm 8 of the jaw 3 is provided with teeth 1 9 and 20 facing in opposite directions. The teeth are in pairs engagged with hwo gear wheels 21 and 22 mounted on shafts 23, 24 which are supported by the frame and are perpendicular to the plane of the supporting arms and located between the supporting arms 4 and 8 and between the supporting arms 5 and 8, respectively.

The jaws 2, 3 are shown in the intermediate position in Figure 3. When pressure fluid is introduced into the cylinder 1 3 to the cover side of the piston, the piston rod pulls the supporting arm 8 and the jaw 3 away from the first jaw 2 whereby both gear wheels rotate around their shafts due to the action of the teeth of the supporting arm 8. The movement of the gear wheels forces the supporting arms 4, 5 of the jaw 2 to move an equally long distance in the opposite direction with respect to the movement of the supporting arm 8 so that the jaws are displaced away from each other to the opened extreme position.

When pressure fluid is introduced into the cylinder to the opposite side of the piston, the piston rod pushes the supporting arm 8 and the jaw 3 towards the first jaw 2 whereby both gear wheels again rotate around their shafts due to the action of the teeth of the supporting arm 8. The movement of the gear wheels forces the supporting arms 4, 5 of the jaw 2 to move an equally long distance in the opposite direction with respect to the direction of movement of the supporting arm 8 so that the jaws are displaced towards each other to the closed extreme position.

In the construction described the gear wheels, in spite of their rotary movements, maintain their fixed position with respect to the frame. Due to this, the centre between the gaps 2a, 3a of the jaws will always be centred in the drilling centre PK of the drilling machine, Fig. 1 even though the jaws carry out a mutual movement. The drill rod can in this way be reliably centred into the drilling centre.

The embodiments shown in Figures 6 to 9 differ from the one described above only with respect to the position of the actuating means.

In Figure 6 a pressure fluid cylinder 63 included in the actuating means is mounted as a separate unit on the frame 1. The piston rod of the cylinder is fastened to the supporting arm 8 of the inner jaw 3.

In Figure 7 the actuating means comprises two pressure fluid cylinders 73, 73' which are mounted as separate units on the frame 1. The piston rod of each cylinder is fastened to one of the supporting arms 4 and 5, respectively, of the outer jaw 2.

In Figure 8 the actuating means comprises two pressure fluid cylinders 83, 83' in which the cylinder bores are formed directly in the frame 1 in the manner shown in Figure 3. The piston rod of each cylinder is fastened to one of the supporting arms 4 and 5, respectively, of the outer jaw 2.

In Figure 9 a pressure fluid cylinder 93 included in the actuating means is mounted as a separate unit on the frame 1. The piston rod of the cylinder is fastened directly to the outer jaw 2.

If desired, it is also possible to mount the actuating means to act on the supporting arms of each jaw, e.g., by combining the constructions shown in Figures 2 and 8 in the same device.

In the construction shown in Figure 10 no separate piston is used but the ends of the supporting arms 4, 5 and 8 at the same time operate as pistons. On the supporting arms are mounted sealings 104, 105 and 108 which seal the arms in corresponding bores 103, 103' and 103" formed in the body and operating as pressure fluid cylinders.

In this construction the jaws 2, 3 are opened by supplying pressure fluid into the bores 103 and 103" whereby the supporting arms 4 and 5 move outwards. the jaws 2, 3 are in a corresponding manner closed by supplying pressure fluid into the bore 103' whereby the supporting arm 8 moves outwards.

In this construction only one arm 4 or 5 can be used for opening of the jaws because the movement of one of the arms is through the gear wheel mechanism transmitted to the other arm 5 or 4 causing a corresponding displacement thereof.

The drawings and the description relating thereto are only intended to illustrate the idea of the invention. In its details the guide according to the invention may vary within the scope of the

Claims

claims. Claims

1. A drill rod guide for a drilling machine, said guide (0) comprising a frame (1), two jaws (2, 3) displaceably supported by said frame by means of supporting arms (4, 5, 8) and provided with gaps (2a, 3a) for the drill rod, connecting means for connecting said supporting arms to each other so that the jaws are displaced in opposite directions when the gaps are opened and closed, and at least one actuating means (11, 12, 1,3,63; 73, 73'; 83, 83'; 93;; 103, 103', 103") for displacing said jaws, characterized in that said connecting means comprise transmission wheels (21,22) mounted in said frame and engaging said supporting arms (4, 5, 8) for the jaws (2, 3) so that the displacement of one of the jaws with respect to the frame causes a displacement of the same extent in the opposite direction of the other jaw with respect to the frame, and at least one of the jaws (2 or 3) is subjected to the action of said actuating means 11, 12, 13; 63; 73, 73'; 83, 83r; 93; 103, 103', 103").

2. A guide according to claim 1, characterized in that said transmission wheels (21,22) are gear wheels, and in that said supporting arms (4, 5, 8) are gear racks.

3. A guide according to claim 2, characterized in that said supporting arms (4, 5, 8) are mounted in parallel bores (6, 7, 9) formed in the frame (1).

4. A guide according to claim 1, characterized in that said actuating means (11, 12, 13) comprises a pressure fluid cylinder (13) the piston rod (11) of which is fastened to said supporting arm (8) of the other jaw (3).

5. A guide according to claim 1, characterized in that said actuating means (73, 73'; 83, 83') comprises two pressure fluid cylinders the piston rods of which are fastened to said supporting arms (4, 5) of the first jaw (2).

6. A guide according to claim 1, characterized in that said actuating means (93) comprises a pressure fluid cylinder the piston rod of which is fastened to the first jaw (2).

7. A guide according to claim 1, characterized in that said actuating means (103, 103', 103") comprises three pressure fluid cylinders th pistons of which are connected to said supporting arms (4, 5, 8) of both jaws.

8. A guide according to claim 7, characterized in that said supporting arms (4, 5 8) of the jaws operate as pistons in said cylinders.

9. A guide according to claim 4, 5 or 6, characterized in that said cylinder (13) or said cylinders, (83,83'; 103, 103', 103"), respectively, are formed in the frame (1).

10. A guide according to claim 4, 5 or 6, characterized in that said cylinder (63; 93) or said cylinders (73, 73'), respectively, are fastened to the frame (1).