GB2032816A

GB2032816A - Annular movement mechanism for drilling machine

Info

Publication number: GB2032816A
Application number: GB7934236A
Authority: GB
Original assignee: Tampella Oy AB
Current assignee: Tampella Oy AB
Priority date: 1978-10-04
Filing date: 1979-10-03
Publication date: 1980-05-14
Also published as: FI783018A; DE2940004A1; FR2443565B1; FR2443565A1; GB2032816B; CA1114720A; SE7908173L; ZA795265B

Abstract

The feed mechanism (3) for a rock drill (1) can be swung about an axle (5) between horizontal and vertical positions by means of a hydraulic cylinder (6) under the control of a directional valve (10). The feed mechanism (3) can also be tilted by means of a second hydraulic cylinder (12) of limited-stroke to establish a desired "look-out" angle for the drill feed direction, the second cylinder (12) being driven by a third hydraulic cylinder (13) under the control of a second directional valve (20). <IMAGE>

Description

SPECIFICATION Improvements relating to drilling machines This invention relates to a swinging mechanism for the drill feed mechanism of a drilling machine, such as a rock drill.

When drilling blast holes for a tunnel, especially contour holes it is necessary to tilt the feed mechanism so that the drilling direction deviates some degrees outwards of the longitudinal axis of the tunnel. The reason for this is that the outermost point of the profile of the drilling machine is farther outwards the centre of the drill rod, whereby the cross area of the tunnel would decrease in steps, if not a small deviation of the feed mechanism and the drilling machine as well as the drill rod from the direction of the longitudinal axis of the tunnel, in other words a socalled "look-out", takes place.

A drilling machine of the above mentioned type is known for solving this problem. In this drilling machine the feed mechanism is swung by swinging the cradle of the feed mechanism by means of the first hydraulic cylinder. The "lookout" angle is accomplished by means of the second hydraulic cylinder which is arranged between the cradle and the feed mechanism. Yet this construction brings following disadvantages.

It causes additional weight at the boom head. In addition to the second cylinder, also its hoses have to be brought there. Because the second cylinder has to move the feed mechanism it has to be of stable construction as well as its fastenings, which further adds to the weight. All this increases also the price. This known construction is neither adaptable to conventional constructions (e.g.

Finnish patent No. 40624) as auxilia-ry equipment.

An object of the invention is to create "lookout" automatics for tilting the feed mechanism of the drilling boom from its basic position by means of a simpler, lighter and less expensive construction which is easy to adapt to conventional boom hydraulics even as auxiliary equipment.

The present invention resides in a swinging mechanism for the feed mechanism of a drilling machine, said mechanism comprising a first hydraulic cylinder with a piston and a piston rod to turn the feed mechanism about an axis which is transverse to the longitudinal axis of the feed mechanism, i.e. the drilling direction, a first directional control valve to control the first cylinder for swinging the feed mechanism, a second hydraulic cylinder connected in parallel with the first cylinder and means including a second directional control valve to control the second cylinder, so that the stroke of a piston of the second cylinder effects a corresponding stroke of the piston of the first cylinder to establish a "look-out" angle for the feed mechanism which is determined by the stroke of the piston of the second cylinder.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing which is a hydraulic circuit diagram of a direction changing mechanism according to the invention for the feed mechanism of a drilling machine.

A drilling machine 1 drives a drill rod 2. In order to drill, the machine 1 and the drill rod 2 can be fed forwards and backwards by means of a feed mechanism 3 which is mounted on a cradle 4.

Swinging of the cradle 4, the feed mechanism 3, the drilling machine 1 and the drill rod 2 about an axle 5, which is transverse to the drilling direction, is accomplished by means of a hydraulic cylinder 6, by means of which the feed mechanism 3 and the drilling machine 1 can be turned between the horizontal and vertical positions. In order to accomplish these movements, the cylinder 6 is controlled by a directional control valve 10 which directs pressure fluid selectively into either of the cylinder chambers 7, 9 which are situated on opposite sides of the piston 8 of the cylinder 6.

This control circuit includes further a pressurereleased non-return valve 11 to lock the jack 6 hydraulically in position.

The mechanism for "look-out" automatics is coupled to this conventional swinging mechanism for the feed mechanism of the drilling machine in the following way. A second jack 12 is coupled in parallel with the first cylinder 6 so that the cylinder chambers 1 6 and 17 of the cylinder 12 are connected respectively to the cylinder chambers 7 and 9 of the cylinder 6. Thereby the movements of the piston 1 5 of the second cylinder 12 can cause the corresponding movements of the piston 8 of the cylinder 6. By choosing, for example, the same cylinder diameters and by limiting the movement of the piston 1 5 to a certain travel it is possible to establish a predetermined "look-out" of the feed mechanism 3 by means of the movement of the piston 15, through the cylinder 6.

A third hydraulic cylinder 1 3 with a piston 18 and a piston rod 21 functions as an operating cylinder for the second cylinder 12. In the present embodiment, the second and the third cylinders 12 and 13 form a double cylinder, the pistons 1 5 and 18 of which have a common piston rod 21.

For the control of the operating cylinder 1 3 there is a directional control valve 20 which thus controls the second cylinder 12 through the third cylinder 1 3. Pressure oil is fed by a hydraulic pump P, the feed circuit of which is provided with a relief valve 23 to limit the pressure in the circuit so that the maximum pressure for which the hydraulic circuit is designed is not exceeded.

The "look out" angle needed for the contour holes is generally about 40. In order to achieve this "look-out" angle, the function of the swinging mechanism according to the invention is as follows.

The directional control valve 20 which receives pressure oil from the same hydraulic pump P as the first cylinder 6 directs pressure into the chamber 17 of the operating cylinder 13, whereby the piston 1 8 starts to move, expelling oil from the chamber 1 9 through the valve 20 to a receiver R.

By means of the rod 21, the piston 18 pushes the piston 1 5 which pushes oil from the space 1 6 through a pressure released non-return valve assembly 22 into the chamber 7 of the cylinder 6.

Thereby the piston 8 of the cylinder 6 is moved a distance determined by the stroke of the piston 15. If the same diameter and the same rod thickness are chosen for the cylinders 6, 1 2 and 1 3, the stroke of the piston 8 corresponds to the stroke of the pistons 1 5, 1 8. Oil flows from the chamber 9 of the cylinder 6 into the chambers 14 of the cylinder 12. The stroke of the piston 1 5 has been chosen so that the whole stroke causes a desired "look-out" angle, of, for example, 40. In order to change the "look-out" angle it is easy to make the stroke of the piston 1 5 adjustable. The feed mechanism 3 is returned to the basic position by adjusting the valve 20 into the opposite position to that which causes the "look-out".

Claims

1. A swinging mechanism for the feed mechanism of a drilling machine, said mechanism comprising a first hydraulic cylinder with a piston and a piston rod to turn the feed mechanism about an axis which is transverse to the longitudinal axis of the feed mechanism, i.e. the drilling direction, a first directional control valve to control the first cylinder for swinging the feed mechanism, a second hydraulic cylinder connected in parallel with the first cylinder and means including a second directional control valve to control the second cylinder, so that the stroke of a piston of the second cylinder effects a corresponding stroke of the piston of the first cylinder to establish a "look-out" angle for the feed mechanism which is determined by the stroke of the piston of the second cylinder.

2. A swinging mechanism according to claim 1, wherein a third hydraulic cylinder, controlled by said second directional control valve, is provided for operating the second cylinder.

3. A swinging mechanism according to claim 2, wherein the pistons of the second cylinder and the third cylinder are interconnected by a common piston rod.

4. A swinging mechanism according to claim 2 or 3, wherein the third cylinder, in order to be controlled, is connectible through the second directional control valve to a hydraulic pressure source to which also the first cylinder is connectible by the first directional control valve.

5. A swinging mechanism according to any of claims 2 to 4, wherein the diameter of the second cylinder is equal to the diameter of the first cylinder and/or the third cylinder.

6. A swinging mechanism according to any of claims 2 to 5, wherein the stroke of the second cylinder is equal to the stroke of the third cylinder.

7. A swinging mechanism according to any of claims 1 to 6, wherein the stroke of the piston of the second cylinder is limited so that it establishes a predetermined "look-out" angle to the feed mechanism.

8. A swinging mechanism according to claim 7.

wherein the stroke of the piston of the second cylinder is adjustable.

9. A swinging mechanism for the feed mechanism of a drilling machine, constructed and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawing.