CA1114720A

CA1114720A - Turning mechanism for the feed of a drilling machine, especially a rock drill

Info

Publication number: CA1114720A
Application number: CA336,880A
Authority: CA
Inventors: Matti Leppala; Veikko Heikkila
Original assignee: Tampella Oy AB
Current assignee: Tampella Oy AB
Priority date: 1978-10-04
Filing date: 1979-10-03
Publication date: 1981-12-22
Also published as: ZA795265B; FI783018A7; SE7908173L; GB2032816B; FR2443565A1; GB2032816A; FR2443565B1; DE2940004A1

Abstract

Turning Mechanism for the Feed of a Drilling Machine, Especially a Rock Drill Abstract of the Disclosure This invention relates to a turning mechanism for the feed of a drilling machine, especially a rock drill. The mechanism comprises a first hydraulic cylinder with a piston and a piston rod to turn the feed round an axle which is transversal to the longitudinal axis of the feed, i.e. to the drilling direction. It also comprises a directional control valve to control the first cylinder, a second hydraulic control with a piston to turn the feed, a directional control valve to control the second cylinder and a hydraulic pressure source. The second hydraulic cylinder is coupled parallel to the first cylinder so that the stroke of the piston of the second cylinder by means of the stroke of the piston of the first cylinder causes a look-out angle for the feed which is determined by the stroke of the piston of the second cylinder.

Description

472~ -This invention relates to a turninq mechanism for the feed oF a drilling machine, especially a rock drill, said mechanism comprising a first hydraulic cylinder with a piston and with a piston rod to turn the feed round an axle which is transversal to the longitudinal axis of the feed, i.e. to the drilling direction, a directional control valve to control the first cylinder, a second hydraulic cylinder with a piston to turn the feed of the drilling machine, a directional control valve to control the second cylinder and a hydraulic pressure source.

When drilling blast holes for a tunnel, especially contour holes it is necessary to turn the feed so that the drilling direction deviates some degrees outwa-rds of the longitudinal axis of the tunnel. The reason for this is- that the highest point of the profile of the drilling machine is farther outwards than 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 and the drilling machine as well as the drill rod from the direction of the longitudinal axis of the tunnel, in other words a so-called look-out, took place. -A drilling machine of the above mentioned type is known for solving this problem. In this drilling machine the feed is turned by turning the cradle of the feed by means of the first hydraulic cylinder. Thereby also the feed is turned. The look-out angle is accomplished by means of the second hydraulic cylinder which is between the cradle and the feed. 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 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 .' ~ '.
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construction is neither adaptable to conventional constructions (e.g. our patent 40624) as auxiliaxy equipment.

The object of the invention is to create look-out automatics for turning the feed 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.

In order to achieve this object the invention is characterized in that the second hydraulic cyinder is coupled parallel to the first cylinder so that the stroke of the piston of the second cylinder by means of the stroke of the piston of the first cylin-der causes a look-out angle for the feed which is determined by the stroke of the piston of the second cylinder. The piston of the second cylinder has a length of free axial movement which limits the stroke of the piston and provides a pre-determined look-out angle for the feed.

In the following a preferable embodiment of the invention will be described with reference to Fig. 1 of the accompanying drawing which shows a direction changing mechanism according to the invention for the feed of a drilling machine.

Number 1 referes to a drilling~machine which operates a drill rod 2. In order to drill they can be fed forwards and backwards along the feed 3 which is mounted on a cradle 4. Turning of the cradle 4, the feed 3,the drilling machine 1 and the drill rod 2 round an axle 5 which is transversal to the drilling direction is accomplished by means of a hydraulic piston cylinder 6, by means of which the feed and the drilling machine can be turned ~.`' '. .
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between the horizontal and vertical positions. In order to accomplish these movements the cylinder 6 is controlled by a directional control valve 10 to direct pressure fluid into either of the cylinder spaces 7, 9 which are situated on opposite sides of the piston 8 of the cylinder 6. This control circuit includes further a pressure-operated non-return valve 11 to maintain the position of the cylinder 6.

The mechanism for look-out automatics according to the inven-tion is coupled to this conventional turning mechanism for the feed of a drilling machine in the following way. A second piston cylinder 12 is coupled parallel to the first piston cylinder 6 so that the cylinder space 16 is connected to the cylinder space 7 and the cylinder space 14 is connected to the cylinder space 9. Thereby the movements of the piston 15 of the second piston cylinder 12 can cause the corresponding move-ments of the piston 8 of the piston cylinder 6. By choosing for .~

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~ Z ~ 3 example the same cylinder diameters and by limiting the movement of the piston 15 to a certain length it is possible to cause a predetermined look-out of the feed 3 by means of the movement of the piston 15, through the cylinder 6.

A third hydraulic cylinder 13 with a piston 18 and a piston rod 21 functions as 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 15 and 18 of which have a common piston rod 21.
For the control of the operating cylinder 13 there is a directional control valve 20 which thus controls the second cylinder 12 through the third cylinder 13. Pressure oil is fed by a hydraulic pump P, the feed circuit of which comprises a relief valve 23 to limit the pressure in the circuit so that the constructional maximum pressure is not exceeded.

The look-out angle needed for the contour holes is generally about 4.
In order to achieve this look-out angle, the function of the turning 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 space 17 of the operating cylinder 13, whereby the piston 18 starts to move pushing oil from the space 19 through the valve 20 to a receiver R.
By means of the rod 21 the piston 18 pushes the piston 15 which pushes oil from the space 16 through a pressure-operated valve 22 into the space 7 of the cylinder 6. Thereby the piston 8 of the cylinder 6 moves 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, 12 and 13, the stroke of the piston 8 corresponds to the stroke of the pistons 15, 18.
From the space 9 of the cylinder 6 oil flows into the space 14 of the cylinder 12. The stroke of the piston 15 has been chosen so that the whole stroke causes a desired look-out angle, for example 4. In order to change the look-out angle it is easy to make the stroke of the piston 15 adjustable. The feed 3 is returned into basic position by adjusting the valve 20 into the opposite position to that which causes the look-out.

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4 1~14'7~0 SUPPLEMENTARY DI SCLOSURE

It has now been found that an improved mechanism may be pro-vided for limiting the stroke of piston 15 in cylinder 12.
This mechanism is shown in Fig. 2 of the drawings, which is a longitudinal sectional view through a double-cylinder providing the second and third cylinders of the turning mechanism. The reference numerals used in Fig. 2 correspond to those used in Fig. 1. Referring to Fig. 2, the cylinders 12 and 13 com-prise a double-cylinder with an intermediate head 24 between the two components. On either side of the intermediate head 24 runs a piston rod 21 whose one end is fitted with a piston 15 and the other with a piston 18. Each piston 15, 18 moves within its own cylinder space. The stroke of piston 15, i.e.
the free axial movement of piston 15 in its own cylinder 12, dètermines the stroke of piston 8 in the first cylinder 6.
This free axial movement of piston 15 is limited by means of a sleeve-shaped spacer 25. By varying the axial thickness of spacer 25, it is possible to obtain various strokes for piston 15 and thus for piston 8 as well and also various look-out angles for the feed 3.

~, Cylinders 12 and 13 are secured to each other by flanges 26 pressed against each other by screw bolts 27. Intermediate head 23 is sealed on cylinder faces by means of O-rings 34.
The middle part of piston rod 21 is provided with a thickened section 28 against which pistons 15 and 18 are squeezed by means of screws 29. The thickened section 28 is slidably : ~ .
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passed through an aperture in the intermedlate head 24 and sealed with seals 35. Pistons 15 and 18 are sealed against the piston rod 21 by means of O-rings 30 and against the inner faces of cylinders by means of seals 31. Through an inlet nipple 32 oil is passed into cylinder space 19 and through outlet nipple 33 from cylinder space 14 into the space 9 of cylinder 6.

The structure shown in Fig. 2 has been found to provide a number of advantages including simple technical construction which ensures reliable operation. The structure avoids the need for limit switches or other expedients, which are often found to be unreliable in mines and other excavating conditions.
The double-cylinder can be mounted anywhere upon the drilling apparatus and connected with hoses to the rest of the hydraulic system; post-fitting can be effected easily. In operation, the look-out angle can be easily changed as described above.

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Claims

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

1. A turning mechanism for the fee of a drilling machine, said mechanism comprising a first hydraulic cylinder with a piston and a piston rod to turn the feed about an axis which is transverse to the longitudinal axis of the feed, a direc-tional control valve to control the first cylinder, a second hydraulic cylinder with a piston to turn the feed of the drilling machine, a directional control valve to control the second cylinder and a hydraulic pressure source, the second hydraulic cylinder being coupled parallel to the first cylinder so that the stroke of the piston of the second cylinder by means of the stroke of the piston of the first cylinder causes a look-out angle for the feed which is determined by the stroke of the piston of the second cylinder, the piston of the second cylinder having a length of free axial movement which limits the stroke of the piston and provides a predetermined look-out angle for the feed.

2. A turning mechanism according to claim 1, wherein the third cylinder is connected through a directional control valve with a hydraulic pressure source to which also the first cylinder is connected.

3. A turning mechanism according to claim 1 or 2, wherein the diameter of the second cylinder is equal to the diameter of the first cylinder and to the diameter of the third cylinder.

4. A turning mechanism according to claim 1, wherein the stroke of the piston of the second cylinder is adjustable.

CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE

5. A turning mechanism according to claim 4, wherein a spacer is located between the piston of the second cylinder and the end surface of the second cylinder and determines the length of the free axial movement of the piston of the second cylinder, said spacer being replaceable with a spacer of dif-ferent thickness, whereby said length of free axial movement can be changed to adjust the stroke of the piston of the second cylinder.

6. A turning mechanism according to claim 5, wherein the second and third cylinders comprise a double-cylinder comprising two cylindrical components having open inner ends and closed outer ends, and an intermediate head disposed be-tween the inner ends of the components, the components being coupled together with the intermediate head therebetween, and wherein the pistons of the respective cylinders are coupled together by a common piston rod extending through said head.