US3332502A - Rockdrilling device - Google Patents

Description

July 25, 1967 l. v. vlNNIK ROCKDRILLING DEVICE 2 Sheets-Sheet l Filed Jan. 28. 1965 Q RTNN/m f@ 3 m mi July 25,1196?` LVMNNIK y 3,332,502

ROCKDRILLING DEVICE Filed Jan. 28, 1965 2 Sheets-Sheet 2 United States Patent O 3,332,502 ROCKDRILLING DEVICE Igor Vladimirovich Vinnik, Kharkov, U.S.S.R., assigner to Kharkovsky Institute Gornogo mashinostroenia avtomatiki i vychslitelnoi tekhnki, Kharkov, U.S.S.R.

Filed Jan. 28, 1965, Ser. No. 428,662 11 Claims. (Cl. 173-405) ABSTRACT F THE DISCLOSURE A device for drillin0 rocks comprising a striking pin with a head the rear butt portion of which is formed as a concave surface, said head providing impact-free reversing of a liquid jet and smoothly developing into a rod of a smaller cross section, said rod smoothly developing in its rear portion into a hollow widening. Said hollow widening passes through an orifice of a nozzle arranged coaxially with the striking pin and forming a free liquid jet, and enters the inner cavity, also displaced coaxially of a cut-off unit located behind the nozzle, so that with the striking pin in its front position, the widening closes the nozzle orifice on having entered the latter, whereas with the striking pin in its rearward position, the widening enters the cavity of the cut-off unit, and a passage is formed between the nozzle oriice and the outer surface of the striking pin rod, said passage providing for free outow of the liquid from the striking pin along said rod, said liquid on having reached the concave surface of the head, causing forward acceleration of the striking pin.

The liquid which is necessary for the operation of the device, is supplied under pressure along channels provided in the body of the cut-oft unit, said channels ending before the nozzle and being connected to the orifice thereof.

The striking pin performs its reverse travel due to rebounding thereof from the shank of the drill rod in the course of an impact.

The drill is rotated by means of a hydraulic turbine through a reduction gear located in the front portion of the device.

The present invention relates to hydraulic devices for drilling rocks of any hardness by the known mechanical methods, viz by the rotary, percussive-rotary, and percussive methods with automatic control of operation ratings to suit rock hardness.

, Holes in soft and medium rocks are usually made by the use of drills, whereas with hard rock air-operated perforators and percussive-rotary machines are employed.

Application of rock drilling machines is limited and determined by rock hardness and available power, certain disadvantages being inherent in each type of machine involved. For instance, electrical drills do not permit operation ratings to be changed in the process of drilling, whilst air-operated perforators and percussive-rotary machines have low etiiciency due to the loss of compressed air during its production, delivery, and utilization. In addition, percussive-rotary machines consume a considerable amount of compressed air that makes their application diicult and soft rock drilling uneconomic.

An object of the present invention is to eliminate and disadvantages and provide a highly economical device with such percussive and rotary mechanisms which will permit their independent operation as well as independent control of operation ratings automatically changing with rock hardness.

Said rock drilling device comprises: a housing; a striking pin travelling under the action of kinetic energy of a free liquid jet and returning into its initial position by rebounding from a drill rod shank; a cut-off unit controlling liquid outflow depending on the position of the striking pin; and a drill stem rotating mechanism, According to the invention, the striking pin has a head the rear butt of which is shaped so as to provide for impact-free reversal of the liquid jet. The head of the striking pin smoothly develops into a rod of smaller cross-section the end of which rod in turn smoothly develops into a hollow widening portion. The widening portion of the striking pin enters the cavity of the cut-off unit whose body has one or several channels running into the cavity of the cut-ofiC unit and inside the front part thereof, working liquid nassing by way of said channels.

Said device is equipped with a special means to change the striking pin travel by adjusting the position of the drill rod shank.

This means for changing the striking pin travel is a cap which is screwed onto a front projection of the housing so that it can move lengthwise on the front projection, the cap engaging via a thrustbearing, the shank limit collar.

The cut-off unit controlling liquid outow depending on the position of the striking pin consists of a hollow guide and a nozzle, said guide and nozzle having holes which correspond to the cross-section of the widening portion of the striking pin and are so situated that the nozzle is an extension of the guide. The channel for delivering working liquid into the cut-olf unit cavity is formed by the guide outer surface and nozzle inner surface.

The guide is rigidly connected with the nozzle by longitudinal ribs which damp the liquid jet.

To adjust the striking pin reverse travel, the guide contains a screw on the end of which a spring' is placed for accumulating the energy of the striking pin reverse travel, the spring entering the widening portion of the striking pin. The screw has channels through which the cavity of the guide communicates with atmosphere.

The nozzle has a flange covering the peripheral part of the housing section.

The rear part of said device has a chamber formed by the housing rear and side walls and the flange; the chamber contains an elastic reservoir filled with air and serving for hydraulic shock damping. When the reservoir is filled with air its inner wall is protected against bulging by a supporting screen resting with its ends on the nozzle and the housing rear wall.

A weak spring is mounted between the striking pin head and drill stem shank to put said device in operation.

An embodiment of the present invention will be described in the following description given by way of example with reference to the accompanying drawings, wherein:

FIGURE l is a section of said device.

FIGURE 2 is a layout of closed circulation of working liquid to and from said device. In both figures the pressure path of working liquid is indicated by a solid arrow and the return path of working liquid by a dash arrow.

Said device, as shown in FIGURE 1, consists of a percussion and a rotating mechanism and an adjustable drill holder.

The percussion mechanism comprises distribution charnber 1 with connection 2 installed on rear wall 3 of the housing of said device. Rear wall 3 has several holes 4 connecting distribution chamber 1 with annular feeding channel 5 situated between tubular supporting screen 6 and hollow guide 7. The front end of feeding channel 5 terminates in annular slot 8 formed by outer surface 9 of guide 7 and inner surface 10 of nozzle 11 which nozzle has a centrally located nozzle orifice 12. Nozzle 11 iS rigidly connected by means of longitudinal ribs 13 with guide 7 in such a manner that nozzle orifice 12 forms an extension of cavity 14 in guide 7.

The combination of guide 7, nozzle 11 and ribs 13 forms a cut-off unit designed for controlling the liquid jet.

Nozzle 11 is rigidiy fastened with the aid of flange 15 to side Wall 16 of the housing so as to divide the housing cavity into two chambers 17 and 18.

Rear chamber 17 formed by rear wall 3, side wall 16 and flange 15 contains elastic reservoir 19 filled with compressed air and resting on supporting screen 6 the ends of which are fastened in nozzle 11 and to rear wall 3.

Front chamber 18 formed by iiange 15, side wall 16 and body 20 of guide apparatus 21 contains longitudinal guides 22 which are mounted coaxiaily with nozzle orifice 12, fixed to ange 15 and rest on projection 23 of body 20. Guides 22 are made of Textolite or cast iron; their surfaces should be ground.

The striking pin of the percussion mechanism has head 24 whose rear butt 25 is shaped so as to reverse the direction of the liquid jet. Head 24 smoothly develops into rod 26 of smaller cross section, which rod in turn smoothly develops into hollow cylindrical widening portion 27. In particular, rear butt 25 of head 24 may be toroidal.

Head 24 of the striking pin slides along guides 22, and hollow widening portion 27, passing through nozzle orifice 12, to enter cavity 14 of guide 7. Cavity 14 contains an adjusting screw 28 screwed into threaded hole 29 in projection 30 provided on rear wall 3, the rear end of guide 7 abutting against said projection.

Screw 2S has a channel 31 through which cavity 14 of guide 7 communicates with the atmosphere. The front end of screw 28 has a -recoil plate spring 32 mounted in cavity 33 of widening portion 27. Weak starting spring 34 is mounted between striking head 24 and body 20 of guiding apparatus 21.

It should 4be noted that the upper part of chamber 18 in housing side wall 16 has 'holes 35 designed for Ventilating the chamber, whereas the lower part of the chamber has drain hole 36.

The rotating mechanism consists of guide apparatus 21 with body 20 and feeder connection 37 situated in the housing before active hydraulic turbine 38 rigidly put on hollow shaft 39 with driving gear 40 set of its front end. Hollow shaft 39 is mounted in bearings 41 located in projection 42 of reduction gear case 43. Gear 40 is engaged with wheel 44 mounted on intermediate shaft 45 carrying gear 46. Gear 46 is engaged with a wheel 47 mounted in a bearing 48 situated in a projection 49 of reduction gear case 43.

The outer surface of the projection has a thread 50 on which adjusting cap 51 is screwed, said cap being designed for changing the position of shank 52 which rests through thrust bearing 53 against limiting colla-r 54 of shank 52. Shank 52 passes through hollow shaft 39 of hydraulic turbine 38 and is connected with wheel 47 by means of splines 55.

A side washing arr-angement 56 is fastened to the front part of cap 51. Used liquid from the hydraulic turbine chamber is drained through port 57.

Shank 52 is made detachable from the drill stem. The rear butt of shank 52 has a spherical surface 58 on which striking head 24 strikes. Connection between the shank and the drill stem may be conical, flanged or threaded.

The operating principle of said device is as follows:

Working liquid under a head of approximately -10 atm. runs through liexible hoses 59 (FIG. 2) and connection 2 to distribution chamber 1 and at the same time through connection 37 to guide apapratus 21 of hydraulic turbine 38 as well as to connection 56a of washing arrangement 56. On reaching distribution chamber 1 of the percussion mechanism, the liquid passes through hole 4 and annular channel 5 and enters supporting screen 6, thereby compressing the air in cylinder 19. Then the liquid runs towards annular slot 8 through the channel between longitudinal ribs 13 designed for jet damping. By the provision of starting spring 34, whose length and tension are sufficient to keep the striking pin in the backward position, the annular slot between nozzle orifice 12 and widening portion 2'7 of the striking pin (as shown in FIG. l) is held slightly open during starting. Through this slot the liquid flows freely in the form of a jet along the rod of the striking pin. On reaching shaped rear part 25 of head 24 of the striking pin, the liquid reverses its direction of flow. This condition results in the liquid pressure accelerating the striking pin, the latter moving towards shank 52. At a certain moment widening portion 27 of the striking pin enters nozzle orice 12 and closes it on its further travel. Further acceleration of the striking pin is performed by the liquid flowing along rod 26. The length of rod 26 and the working stroke should be so adjusted that a .blow of the striking pin on shank 52 occurs just after using up all the liquid which has passed through nozzle orifice 12.

The used liquid fiows to the inner surface of the housing and runs down it to drain hole 36. At the beginning of reverse travel of the striking pin its path is clear of liquid.

After striking shank 52, the striking pin rebounds backward, part of the kinetic energy that the striking pin posssed before delivering the blow 'being transmitted to shank 52 on application of the impact force and the remaining part being carried away -by the striking pin on its rebound. The velocity of the rebound remains almost constant for the entire reverse travel. At the moment when widening portion 27 of the striking pin opens nozzle orifice 12 on its backward travel a jet of liquid issues to meet the striking pin. However, the striking pin keeps on moving backwards, since the jet which meets the forward part and rear butt 25 of striking head 24 requires a time to cover the length of striking pin rod 26 at a speed equal to the total speed of the jet and striking pin reverse movement.

In this time, the striking pin, moving back, reaches recoil spring 32 and rebounds from it in the Working stroke direction. The major part of the energy of :the striking pin on rebound is returned in the form of the initial speed of its working stroke.

After the jet forward part meets rear part 25 of striking head 24, the striking pin starts accelerating. When the striking pin moves forward its widening portion 27 at a certain moment enters nozzle orifice 12 closing it, and the operating cycle repeats.

For the first two or three cycles after starting, the speed of the blow and rebound as well as the initial speed of the striking pin increases. Then the values of all the ratings become constant, said ratings being determined by the position of recoil 1spring 32 and shank 52 as well as by the magnitude of the rebound.

Starting spring 34 which has low tension and low oscillation frequency remains half compressed and practically has no effect on Ithe operation of the percussion mechanism.

Liquid is supplied to said device uniformly. When the cut-off unit is closed, i.e. widening portion 27 of the striking pin closes nozzle orifice 12, th-e liquid accumulates in chamber 17 compressing the air in cylinder 19. Therefore after nozzle orifice 12 is opened the liquid discharges at a rate several times greater than the mean Irate of flow through supply hose 59. By the provision of cylinder 19, head impacts adversely affecting pump operation are dampened. If the capacity of reservoir 19 is chosen correctly, pressure fluctuations do not exceed 5-7 percent.

By adjusting `the position of recoil spring 32 by means of turning adjusting screw 28 in or tout, it is possible to Change the time for which nozzle orifice 12 remains open,

the amount of liquid passing through it, and, consequently, the energy of the blow the striking pin delivers to shank 52.

Changing the position of shank 52 by screwing cap 51 in or out, makes it possible to change the working stroke and, consequently, the number of blows on shank 52.

Since the speed of rebound of the striking pin from the shank is determined by the magnitude of the rebound coeicient, which is dependent on the properties of the rock being drilled, the ratings of the percussion mechanism operation depend on environmental drilling conditions.

Thus, when a drill meets a Ahard rock layer, this results in increasing the magnitude of rebound coefficient, and speed and, consequently, the initial speed of the striking pin.

As a result of this, it also leads to an increase in the speed of the striking pin blow on the shank and the blow energy, which iinally results in an increased number of blows.

With a soft rock layer the magnitude of rebound, blow energy and number of blows decrease.

By using proper operation ratings on said device it possible to obtain an automatic change in the number of blows and blow energy of the percussion mechanism, which will correspond to optimum conditions of drilling a certain complex of rocks.

The liquid fed to guide apparatus 21 flows to blades 60'of the hydraulic turbine 38, rotates it, and ows out through port 57 into drain pipe 61 (FIG. 2), where it mixes with the liquid used in the percussion mechanism. Rotation of hydraulic turbine shaft 39 is transmitted through the reduction gear to splined portion 55 of shank 52.

The speed and power output `of the turbine is c'ontrolled by valve 62 (FIG. 2) mounted in supply hose `59.

The spent liquid passes from drain pipe 61 through ilexible hose 63 to suction connection 64 of a pump mounted on a separate frame or built in a structure of supporting mechanism (not shown in the drawing), by which pump it is again forced into supply hoses 59. As the circulating liquid continuously expels air from the housing of said device, the housing is provided with holes 3S, whilst air-separating caps 65 mounted and fastened in the upper part of receiver 66 are provided upstream of pump suction connection 64.

T he pump unit is not required if a delivery pipeline is available.

What is claimed is:

1. A device for drilling rocks comprising: a housing; a drill rod with a shank in said housing; a nozzle located in said housing and having an orice for forming a free liquid jet; a. striking pin in said housing performing a working stroke under the action of kinetic energy of the free liquid jet produced by said nozzle and returning to an initial position by rebounding from the shank of said drill rod; a hollow cut-off unit located in said housing adjacent said nozzle for controlling the outow of the liquid in dependence of the position of said striking pin, said cutoff unit having a body with va least one channel passing into a cavity of said cut-off unit for supplying the liquid to said nozzle; said striking pin having a head the rear lbutt of which is shaped to provide impact-free reversal of the liquid jet, said head smoothly merging into a -rod of a smaller cross-section, said rod smoothly merging into a hollow widening portion entering the cavity of said cut-off unit through said orice of said nozzle; and a means for rotating said drill rod, located in the front portion of said housing.

2. A device as claimed in claim 1, wherein said cutoff unit is provided with a hollow guide having an inner cavity, said guide being rigidly connected with said nozzle so that the outer surface of said guide and the inner surface of said nozzle form an annular channel intended for delivering liquid to said striking pin; the inner cavity of said guide and the orice rof said nozzle corresponding to the cross section of said hollow widening portion of said striking pin.

3. A device as claimed in claim 2, comprising longitudinal ribs rigidly connecting said guide to said nozzle for damping the operating liquid jet.

4. A device as claimed in claim 1, wherein the rear butt of said head of said striking pin is toroidal.

5. A device as claimed in claim 1, wherein said housing includes a projection at the front portion thereof, said shank of the drill rod having a limit collar, the device further comprising means for adjusting the travel of the striking pin including a cap screwed on the projection on the front portion of said housing so that the cap can be longitudinally shifted therealong, said cap resting against the limit collar of the shank of said drill rod.

6. A device as claimed in claim 5, wherein said guide has a screw mounted therein for adjusting the length of the striking pin reverse travel, a spring arranged on an end of the screw and entering said widening portion of 4the striking pin for accumulating the energy of the striking pin reverse travel.

7. A device as claimed in claim 6, wherein said screw has channels providing communication between the inner c-avity of said guide and the atmosphere.

8. A device as claimed in claim 1, wherein said nozzle includes a ange covering the peripheral annular cross section of said housing.

9. A device as claimed in claim 8, wherein :a chamber is formed lby the walls of said housing and said flange, yand an elastic annular reservoir in said chamber filled with a gas and adapted for damping hydraulic impact in the supplying system.

1t). A device as claimed in claim 9, wherein `said gas in said reservoir is under pressure, a tubular screen with- ,.in said reservoir for supporting the same, said screen having end portions resting on said nozzle and the rear wall of said housing.

1 1. A device as claimed in claim 1, comprising a weak spring mounted between said head of the striking pin and the shank of the drill rod to start the device.

References Cited UNITED STATES PATENTS 1,605,713 11/1926 Gilman 173--105 2,778,605 l/1957 Hunn 173-105 3,059,618 10/1962 Osgood 173-105 3,157,070 11/1964 Heidrich 173-134 FRED C. MATTERN, JR., Primary Examiner, L. P. KESSLER, Assistant Examiner.

Claims (1)

1. A DEVICE FOR DRILLING ROCKS COMPRISING: A HOUSING; A DRILL ROD WITH A SHANK IN SAID HOUSING; A NOZZLE LOCATED IN SAID HOUSING AND HAVING AN ORIFICE FOR FORMING A FREE LIQUID JET; A STRIKING PIN IN SAID HOUSING PERFORMING A WORKING STROKE UNDER THE ACTION OF KINETIC ENERGY OF THE FREE LIQUID JET PRODUCED BY SAID NOZZLE AND RETURNING TO AN INITIAL POSITION BY REBOUNDING FROM THE SHANK OF SAID DRILL ROD; A HOLLOW CUT-OFF UNIT LOCATED IN SAID HOUSING ADJACENT SAID NOZZLE FOR CONTROLLING THE OUTFLOW OF THE LIQUID IN DEPENDENCE OF THE POSITION OF SAID STRIKING PIN, SAID CUT-OFF UNIT HAVING A BODY WITH AT LEAST ONE CHANNEL PASSING INTO A CAVITY OF SAID CUT-OFF UNIT FOR SUPPLYING THE LIQUID TO SAID NOZZLE; SAID STRIKING PIN HAVNG A HEAD THE REAR BUTT OF WHICH IS SHAPED TO PROVIDE IMPART-FREE-REVERSAL OF THE LIQUID JET, SAID HEAD SMOOTHLY MERGING INTO A ROD OF A SMALLER CROSS-SECTION, SAID ROD SMOOTHLY MERGING INTO A HOLLOW WIDENING PORTION ENTERING THE CAVITY OF SAID CUT-OFF UNIT THROUGH SAID ORIFICE OF SAID NOZZLE; AND A MEANS FOR ROTATING SAID DRILL ROD, LOCATED IN THE FRONT PORTION OF SAID HOUSING.

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