US2288545A - Drilling apparatus - Google Patents

Description

June 30, 1942. c. F. 056000 I Q DRILLING APPARATUS Filed July 26, 1940 QM 9% MW 3 NW 3 f 2 i i 5 l HI n k J: R W w l I. l .Nm. 3 R :3 \W .Q\ *m I Q m wmwm o M Q & NQMN Q Patented June B50, 1942 .UNITED STATE DBILLING APPARATUS Charles F. Osgood, Claremont, N. fl rassignor to Sullivan Machinery Company, a corporation of Massachusetts Application July 26, 1940, Serial N0. 347,716

15 Claims. (01. 255-47) This invention'relates to drilling apparatus, and

more particularly, but not exclusively, to improvements in drilling apparatus of the high speed rotary type especially designed for use with abrasive type hits such as diamond core bits.

In drilling apparatus utilizing abrasive type hits, such asdiamond core drills, and particularly those of the high speed type, it is essential that a steady stream, of cleansing fluid be supplied to the drill bit to prevent damage to the bit by overheating due to' friction and abrasion. In high speed drills such as diamond core drills for drilling blast holes in relatively hard rock, the diamond bit would be quickly destroyed if it were operated without an adequate supply of cooling fluid, and it therefore must be certain that cooling fluid has reached the drill bit at the hole bottom prior to the starting of the bit rotating motor. In previously known types of drilling apparatus the motor control is operable independently of the cleansing liquid supply control, so that it has been possible to start the motor while the liquid supply to the bit was cut off.

It is a primary object of the present invention to provide improved drillingmeans wherein the j bit rotating motor is started only after the cleansing fluid has been conducted'to the drill bit. Another object is to provide an improved control means for the bit rotating motor of a rotary drilling apparatus wherein the control means is responsive to the pressure of fluid in the cleansing fluid supply for automatically starting the bit rotating motor when the cleansing fluid has reached the bit and when the rod line bore and the associated fluid supply passages are completely filled with fluid. Yet another object is to provide an improved fluid actuated motor control means responsive to the pressure of the fluid in the cleansing fluid supply to the drill bit whereby when the fluid has reached the bit, the bit rotating motor is automatically started. A still further object is to provide an improved motor control means operable to stop the bit'rotating motor upon failure of the supply .of cleansing fluid to the drill bit, or inthe event the fluid supply is inadvertently cut off. Yet another object is toprovide improved-means for automatically stopping the bit rotating motor during withdrawal of the bitgfrom the drill hole. These and other objects and advantages of the invention will, however, hereinafter more fully appear.

In the accompanying drawing there is shown for purposes of illustration one form which the invention may assume in practices In thisdrawing: I

Fig. l is a side elevational ,view of a drilling apparatus in which an illustrative embodiment of the invention'is incorporated.

Fig. Zis an enlarged view in longitudinal vertical section taken through a portion of the drilling apparatus shown in Fig. land illustrating the improved cleansing fluid supply and motor control means.

Fig. 3 is an enlarged view in longitudinal section taken through the drill rod and drill bit.

In this illustrative embodiment of the inventionthe improved cleansing fluid supply and rnotor control means is incorporated in a drilling apparatus of the high speed rotary core type es'- pecially adapted to use with abrasive type bits, such as diamond core bits. The drilling appa-' ratus may be of the same general character as that disclosed in the-copending application of one Win W. Paget, Serial No. 268,792, filed April 19, 1939. It will be evident, however, that the invention may be embodied in drilling apparatus of various other types.

The drilling apparatus disclosed generally comprises bit rotating means, generally designated I, supporting and guiding means, generally designated 2, and bit feeding means, generally designated 3. The bit rotating'means 1 comprises a rotary motor 4, herein preferably a 'totally-enclosed, high speed electric motor comprising a motor casing 5 containing an armature rotor 6 I keyed to a shaft 1 journaled in .ball bearings 8, 8

suitably supported within the motor casing. Carried by the motor shaft I is a chuck 9 for receiving the shankof a drill rod [0, the latter in turn carrying a diamond core bit I I. As shown in Fig. 3, the drill rod Ill has a bore l2, and the drill bit I l is in the form of an annulus secured to a tubular member l3 coupledat M to the drill rod, the

bore in the tubular member communicating directly with the rod bore. The motor is mounted in a control head I5 in the manner described in the application above referred to, and the control head is supported by an element of the feeding means 3. The feeding means is of the fluid actuated type and comprises a feed cylinder l6 containing a reciprocable feed piston having its piston rod extending forwardly through-the front cylinder head. Secured to the front end of the piston rod'ls an end plate H. to which the control head I5 is rigidly secured. The supporting and guiding means 2 comprises a guide member It! in which the feed cylinder of the feeding means is supported and guided, and this guide member is mounted on a trunnion member 19 having a swivel plate 29. adapted to be clamped in the saddle mounting of a conventional drill support. The control head I! has a chamber 2| in which is arranged a motor switch 22 for controlling the prises a fluid supply chamber 29 having a usual 1 fluid supply. connection 29 leading to any convenient source of fluid pressure supply. Arranged in this chamber is a strainer 21 through which the fluid must. flow to reach the space in the chamber 29 surrounding the strainer. Also formed in the control head II is a bore 29 receiving a ported valve bushing 29 in which is slidably mounted a valve 39. This valve is of the sliding spool type and has suitable operating rod connections 3| provided with fan operating handle 321'herein located at the rear end of the feeding means 3. This slide valve is adapted to control the flow of liquid in the chamber through a passage 33 to a chamber 34 also formed in the control head.

In this illustrative construction, clamped between a member 39 and the end plate carried by the feed piston rod is a diaphragm 39, and the adjacent faces of the elements I! and 39 are recessed to provide a diaphragm chamber 39 therebetween. The diaphragm 36 engages at its forward side a spring-pressed plunger 39 guided in an axial bore 40 in the member 35; and this plunger is constantly urged by a coil spring 4| toward its rearmost position, as shown in Fig. 2. The plunger 39 engages the operating means for the switch 22. When the plunger 39 is in the position of Fig. 2 the motor circuit is open. When the central portion of the diaphragm moves a predetermined distance toward the left in Fig. 2. the switch 22 will close to start the motor. A passage 42 connects the chamber 34 to an annular recess 43 opening directly into the diaphragm chamber at the rear side of the diaphragm. The spring oflers substantial resistance to closing of the switch, as will later be explained.

Cleansing fluid may be supplied to the drill bit through a fluid conducting tube 44, threadedly secured at 49 within a member 49 secured to the control head It and providing a closure for the forward side of the control head chamber 2|. The tube 44 extends axially through a bore 41 in the motor shaft 1 and passes at'its forward end through a stufllng box 49 arranged within the forward end of the motor power shaft. Fluid may flow from the tube 44 through a bore 49 in a packing adjusting plug 50 and through a bore 5| in a coupling member 92 to the bore |2 of the drill rod and thence to the drill bit. A passage 53 in the member 49 communicates with a passage 54 in the control head, the latter passage leading to the chamber 34. The flow area of the passages 54, 53 to the drill rod bore should aaeaws previously formed in the working face.

close until such filling has been completed, under normal conditions.

The mode of operation of theimproved drilling apparatus is as follows. When the drilling apparatus is set up in proper drilling position with respect to the working face, as shown in Fig. 1, the swivel plate of the supporting and guiding means 2 is clamped in the saddle mounting of a drill support in the mannerwell nown to those skilled in the art. The drill rod 9 carrying the drill bit II has its shank inserted within the chuck 9, and the drill bit is fed forwardly by the feeding means 3 into its initial drilling position within a starting hole The operator may then adjust the manual slide valve, 39 to admit liquid under pressure from the supply chamber 25 to the chamber 34. Liquid may flow freely from the chamber 34 through the passages 54, 53 to the fluid conducting tube 44 andthence through the bores 49 and ii and the drill rod bore |2 to the drill bit at the bottom of the drill hole. Liquid may also flow through the passage 42 to the annular recess 43 to act on the rear surface of the diaphragm. During flow of liquid through the drill rod bore to the drill bit, until the passageways become filled with liquid the pressure of the liquid in the chamber 34, passage 42 and. annular recess 43 is insufficient to overcome the spring 4| which opposes movement of. the plunger 39 forwardly from the position shown in Fig. 2, so that starting of the bit rotating motor is prevented. However, when the drill rod bore and the associated liquid supply passages are completely filled and cleansing liquid has reached the drill bit, the pressure of the liquid in the chamber 34 builds up to substantially line pressure, and this built up pressure acts on the diaphragm to move the plunger 39 forwardly against the tension of the spring 4| into its position to operate the switch 22 to start the bit rotating motor.

In .the event of failure of the liquid supply or inadvertent movement of the slide valve 39 into its position to cut off theflow of liquid to the chamber 34, the pressure in the chamber 34 would drop sufficiently to cause the coil spring 4| to move the plunger 39 rearwardly into its position to operate the switch 22 to stop the bit rotating motor. It is accordingly evident that liquid supply to the drill bit is assured prior to starting of the bit rotating motor, thereby preventing the possibility of destruction of the drill bit due to the lack of suflicient cooling liquid. This safety feature also assurs stopping of the bit rotating motor in-the event the liquid pressure supply fails for any reason or is inadvertently manually cut off. It is also evident that there is substantial delay in the starting of the bit rotating motor while the liquid flowing through the drill rod bore to the bit completely fills the drill rod bore and the associated supply passages so that access of liquid to the bit is assured prior to the starting of the bit rotating motor. To preventwhipping of the drill rod in the drill hole and possible injury to the diamond bit due to engagement with the walls of the drill hole during withdrawal of the drill bit from the hole, it is desirable to stop rotation of the bit during this operation. Upon retraction of the drill bit from the drill hole a substantial drop in the pressure of the liquid in the drill rod here will occur, and this drop in pressure causes the coil spring 4| to move the plunger 39 rearwardly to operate the motor switch to stop the motor.

. motor to prevent damage to the bit due to deflection orjamming. Other uses and advantages of the improved drilling apparatus will be clearly apparent to those skilled in ,the art, W/

While there is in this application specifically described one form which the invention may assume in practice, it will be'understood that this form of the same is shown for purposes of illustration and that the invention may be modifled and embodied in variousother forms without departing from its spirit or the pended claims. ,1 I

What I claim as new and desire .to secure by Letters Patent is;

1. In a drilling apparatus, the combination comprising means for rotating a drill bit, valvecontrolled means for conducting cleansing fluid to the drill bit, fluid actuated means for controlling said bit rotating means, and means for. starting said bit rotating means after the cleansing fluid flowing through the conducting means controlled means for conducting cleansing fluid to the drill bit, fluid actuated control means for scope of the appressure of such liquid reaches a predetermined value ior automatically starting the bit rotating motorwhen the liquid supply reaches the drill bit and has completely filled the hollow interior of the drill rod and a predetermined pressure has built up in said conducting means.

5. In a drilling apparatus, the combination comprising means for rotating a drill bit, means for conducting cleansing liquid to the drill bit,

. fecting initiation of operation of said bit roand means for controlling the operation of said 'bit rotating means including a fluid actuated control element, and means for automatically eftating means after the liquid flowing through said conducting means reaches the drill bit, including means subjecting said control element to the pressure of the liquid in said conducting means whenever any exists therein.

6. In a drilling apparatus, the combination comprising a motor for rotating a drill bit, means for conducting cleansing liquid to the drill'bit, and control means for automatically starting said motor after the liquid in said conducting means reaches the drill bit, said control means including liquid actuated motor control means sub- Jected to the pressure of the liquid in said conducting means whenever any exists therein, said motor control means including means for precluding actuation thereof to effect motor starting until the pressure of the liquid in said conducting means reaches a value in excess of that which is attained during free liquid discharge ,from said liquid conducting means.

starting said motor, and means for effecting starting of said motor after the cleansing fluid flowing through the conducting means reaches the drill bit including means for subjecting said fluid actuated control means to the pressure of the fluid in said conducting means, said subject-, ing means including a passage connecting withsaid conducting means at a point at the bit side of the control valve for said conducting means. i

3. In a drilling apparatus, the combination comprising a hollow drill rod carrying a drill termined pressure in said conducting means, in-

cluding continuously open means for subjecting said control means to the pressure of the cleansing liquid flowing through said conducting means, said fluid actuated control means including means for precluding operation thereof to start said drill rod and bit rotating means until said fluid actuated control means is subjected to such a predetermined pressure.

4. In a drilling apparatus, comprising a hollow drill rod carrying a drill bit, a motor for rotating the drill rod and bit, means for conducting cleansing liquid through the drill rod to the drill bit,and means subjected at all times when any. such pressure exists to the pressure of the liquid in said conducting means and operative to effect motor starting only when the the combination '7. In a drilling apparatus, the combination comprising a motor for rotating a drill bit, means for conducting cleansing liquid to the drill bit, and control means for automatically starting said motor after the liquid in said conducting means reaches the drill bit, said control means including liquid actuated motor control means subjected to' the pressure in said liquid conducting means and having means preventing liquid actuation to efiect motor starting until said control means is subjected to substantially line pressure, said control means operating to start said motor whenever the liquid in said conducting means reaches the drill bit and a substantially line pressure is built up in said conducting means.

8. In a drilling apparatus, the combination comprising a motor for rotating a drill bit, a liquid supply, means for conducting liquid'from said liquid supply to the drill bit, a control valve arranged ahead of said liquid supply and governing the admission of liquid to said liquid supply,

control means for starting said motor and including a liquid actuated motor starting device,

.and means for conducting liquid from said liquid supply to said'starting device whereby the motor is automatically started when the pressure of the liquid in said last mentioned conducting means reaches apredetermined point. ,9. In a drilling apparatus, the combination comprising a motor for rotating a drill bit, a

liquid supply chamber, passage means in continuous communication with said liquid supply chamber for supplying liquid from said chamber to the drill bit, fluid actuated control means for for delaying starting of said motor until the liquid supply reaches the drill bit including means for precluding-operation of said control means to start said motor until the liquid pressure in pressure.

10. In a drilling apparatus, the combination comprising an electric motor 'ior rotating a drill bit, a switch for stopping and starting said metor, fluid actuated means for operating said comprising an electric motor for rotating a drill bit, a switch for stopping and starting said motor, fluid actuated means for operating said switch to start said motor. and means for supplying fluid to the drill bit, means for subjecting said switchoperating means to the pressure of the fluid in said supply means including means effecting a continuous communication between i said switch operating means and said supply means, said switch having associated therewith means yieldingly opposing the action of said fluid I actuated switch operating means and operative to prevent starting of said motor so longas unrestricted flow oi fluid takes place through said means forsupplying fluid to the drill bit.

12. In a drilling apparatus, the combination comprising a motor for rotating a drill bit to eflect drilling of a hole, means i'or'conducting cleansing liquid to the drill bit having a control valve-arrangement at the inlet end thereof, and means including a m tor control device subjected to the pressure the liquid in said conducting means for automatically stopping said motor upon a substantial drop in pressure in said conducting means during withdrawal of the drill bit from the drill hole.

13. In a drilling apparatus, the combination comprising means for rotating a drill bit, means for conducting cleansing fluid to the drill bit, a control valve past which cleansing fluid flows to enter said cleansing fluid conducting means, con- I assasss said'chamber has built up substantially to line trol means for eflecting and interrupting operation of said bit rotating means and including a fluid. actuated control element, and means or -subjectlng said fluid actuated control element to the pressure of the fluid in said conducting means .at a point in the latter nearer to the bit than is said control valve wherebyoperation of said bit rotating means is eflected when the pressure in said fluid conducting means reaches a predetermined point and iorautomatically interruptflows to enter said cleansing fluid conducting means, fluid actuated means for operating said control device, and means for subjecting said control device operating means to the pressure 01' the fluid in said conductingmeans at a point nearer to the bit than said control valve is whereby the motor is automatically started when the pressure in said conducting means reaches a predetermined point and for automatically stopiecting said fluid actuated means to fluid comprising passage means communicating with said conducting means between the ends of the latter.

CHARLES F. OSG OOD.

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