US2233421A

US2233421A - Detachable drill bit

Info

Publication number: US2233421A
Application number: US237875A
Authority: US
Inventors: Liddicoat Percill
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-11-15
Filing date: 1938-10-31
Publication date: 1941-03-04
Anticipated expiration: 1958-03-04

Description

March 4Q 1941 QP. LIDDxcoA-r 2,233,421

DETACHABLE DRILL BI T Filed Oct. 5l, 1938 f/ @amv/W 32 ??Lzazyracm;

' JNVENTDR,

Traa/NER Patented Mar. 4, 1941 UNITED STATES PATENT olFFlcE DETACHABLE DRILL Brr Percill Liddicoat, St. Catharines, Ontario, Canada Application october s1, 193s, serial No. 2'37,s75 In Canada November 15, 1937 9 Claims.

In the present invention I have devised a detachable drill bit with modifications, adapted to be easily mounted, and di'smounted from the lend of the shank of a drill 'rod used in boring rock, ore, etc., in mining, and similar operations where boring is required through hard material.

A feature of the invention is that the shank of the drill rod with which the bit is used may have any of the usual cross` sections, such as square, 1'0 hexagonal, octagonal, oval or the like, and the lowerl extremity of the drill rod does not have or require any previously made special shape, or conformation in order to engage the bit, and .the successive blows received by the drill rod in the l boring operation, are transmitted to the bit, and provide a method whereby the bit becomes locked fast to the end of the drill rod. The bit in each of the forms which are described herein; is provided with a socket or recess formed in the body of the bit, said socket having in turn small recesses, grooves, convolutions, corrugations and beveled surfaces formed therein, which are adapted to form on the end of the drill rod, complementary projections, shapes, and surfaces,

whichsecure the bit on the drill rod, as will be more fully described as the description proceeds herein. Moreover the said projections, shapes, surfaces just mentioned are formed on the drill rod, by and during thev normal operation of the drill rod, by means of the impacts received by the drill rod from the machines and devices normally reciprocating, and torsionally operating said rod. A

' The impacts received by the drill rod, being transmitted to the bit, directly over the cutting blades of the latter, tend to bore a `straight hole in the rock or other material being worked; and the torsion of rotation of the drill rod is readily transmitted tothe flattened side walls of the bit socket, as will be fullydescribed below.

'I'he types of bit in 'the present invention can be easily and cheaply manufactured by pressing or drop forging, without-subsequent machining all of which tends to make the use of the bits in large numbers a commercial and practical matter.

This is an important consideration when it is stated that bits have to be very frequently replaced on the drill rod, as they soon become dull on the cutting blades in service.

5o A most important feature is also the ease with which the bit can be detached or dismounted from the drill rod shank, by merely hitting the bit on its outer perimeterl a few blows with a hammer, or the shank of the drill rod canreadily 5 be .withdrawn from the bit socket using tools; in

which event it will be noted that the projections,

enlargements and the like which have 'been formed on the end of the drill rod, are flattened sufficiently to permit the end o f thedrill rod to be re-inserted in other or freshly sharpened bits.

In the accompanying drawing forming part of this specification, I have shown a physical embodiment of the invention, with .several modications, constructed according to the best mode I have so far devised for the practical application 10 of the principles of my invention.

In said drawing, Figure 1 is a f ront elevation, partly in section, of the invention, showing a hexagonal shaped drill rod shank inserted in the bit. i 15 Figure 2 is a top plan view of the bit shown f in Figure 1.

Figure 3 is a side elevation of the device sho in Figure 1, taken from the position indicated in Figure 4; and with part of the device shown in 20 section to show the interior of the bit.

Figure 4 is a bottom view of the bit shown in Figure 3.

Figure 6. Y Figure 8 is a plan view of another modification of the bit.l

Figure 9 is a front view in elevation of the Figure 8. 35

Figure 10 is a vertical section through a portion of a drill bit, illustrating a modied means of mounting a drill rod in the bit socket.-

Figure 11 is avertical section through a ,por-v tion of a drill Abit, illustrating another modified 40 means o'f mounting a drillrod in the socketof the bit.

Figure 12 is an enlarged vertical -section through a portion of a drill bit illustrating in'detail the means for mounting the end of a vdrill rod in the 45 bit socket.

In the drawing, the numeral I indicates a rock cutting drill rod having before its insertion in the socket of the bit 2, a plane fiat surface 3 on its bottom end, and the side walls 4, l being fiat and forming the hexagonal sides of the rod as shown. The bit is provided with the usual cutting teeth, 5, 5, and is provided with the socket or recess 6, formed in cross-section complemen tary tothe drill rod.. At the bottom of the recess 6 are formed a series of

smaller recesses

1, 1, etc., and the bottom I2 of the socket 'in this illustration is concave in shape. On the surface of this bottom are formed bossedV corrugations 9, 9, etc., as clearly illustrated in Figures 1, 2 and 3 of the drawing. `It is pointed out that after the end of the drill rod is inserted in the socket 6 of the bit, the repeated blows on the upper end of the drill rod, drive the rod downward into the bottom of the socket, and the metal of the rod shank 8 forms protrusions or projections I0, I0 thereon, and the metal of the bottom of the drill rod also forms complementary shapes to the convolutions or corrugations 9, 9, the metal being crowded somewhat between each pair of same as is at once understood. The beveled or concaved surface I2, on whichA the corrugations 9, 9 are formed as may be readily understood from Figure 12 tends to form the projections I0, I0 on the end of the drill rod. 'I'here is no objection however so far as the formation -of the projections I0, I are concerned to having the bottom of the recess 6 fiat as at I3, in Figure 10. In the type of the device just -described in reference to Figures 1 to 4 inclusive it is evident that the drill rod I, when itis withdrawn from the bit 2 has the projections I0, I0, etc., flattened out in line with the surface of the side walls of the drill rod, so that the drill rod can readily be used for reinsertion in any other bit, or in the old one after the cutting blades have been re-sharpened for subsequent use.

While in the type of bit and drill rod just described the cross-section of the drill rod is hexagonal, it is evident that any other type of cross-section commonly used, such as a square,

oval, or hexagonal cross-section may be used, if the socket of the bit is made complementary thereto.

In the Figures 5, 6-and 7 of the drawing is shown a modified form of the invention, in which the drill rod is of the. square type, and a continuous groove I4-is formed at the base of the socket or recess I5 of the bit I6. It is evident that the drill rod I1 may be Withdrawn from the bit in the same way as before described, and the projection I8 in lthe groove I4 flattened-out in the same manner as the projections I0, I0 of Figure 1. In some cases the bit may be provided with a central hole or passage. I9, which permits water to pass through the bit, and also is of assistance in removing the rod from the bit. This is true of all the types of bit mentioned in this specification.

In the Figures 8 and 9 of the drawing is shown another modified form of bit, which is provided with

recesses

20, 20, etc., formed in the side walls of the socket 2|', and between the corners22, 22, of the socket 2 I. These various types of recesses, such as 1, 1, and corrugations 9, 9 concaved bottom I2, shown in Figures 1, 2 and 3; the groove I4, Figure 5; and the

small recesses

20, 20 of Figures 8 and 9; may all be used in combination as desired, and as found suitable to the particular cross-sectional shape of the drill rod being used.

In the Figures 10, 11 and 12 is illustrated diagrammatically several features of the invention,

drill rod and the walls of th socket. In other instances it may be found desirable to have the walls of the socket of the bit tapered slightly as illustrated at 21, Figure 11 of the drawing. Moreover this type of beveled or tapered side walls may be used with or without the driven t or binding action just described between the drill rod and the socket walls. In some instances the top edges of the sockets of the bits may have a beveled or flared mouth as at 28, 28 to permit of easy insertion of the drill rod, asis at once undery stood. Also in some cases it may be deemed advantageous to bevel the exterior top edges of the bit as shown at 29 Figure 1, or 30 in Figure 9.

In Figure 12 the advantage of having a concaved bottom I2 for the bit recess, or a beveled partially cone-shaped bottom, is clearly illustrated, as it is at once evident from this enlarged drawing thatwhen the drill rod shank 3I meets the beveled or curved surface I2, at

points

32, 32, there is a tendency to cause the material of the shank' to at once form the desired projecting bosses I0, I0 which are thus formed complementary in shape to the

recesses

1, 1 and form the means of locking the bit on the end of the drill rod; and also to conform the said material to the corrugations 9, 9.

Referring now to the features and advantages mentioned in the preamble of this specification, it is believed after what has been described, that these features are readily understood. Itis especially emphasized that in the present invention, no unusual preparation is needed for the shank of the drill rod, when the present type of drill bit is used; in other words the end and the sides ofthe shank of the drill rod are plane surfaces in correspondence lwith the type of crosssection of the rod being used, square, hexagonal, oval, etc., being used. In many of the drill bit devices in current use the end of the drill shank has to receive considerable preliminary treatment, in order to be used with a special type of bit. In the present device it is evident no preliminary treatment or manipulation lwhatever is required for the end of the said rod other than the use of a cross-sectional shape ofv rod corresponding to the type of socket in the drill bit. Moreover the same shank maybe used many times, after withdrawal from-the bit.

Attention is called to the ease with which the bit is secured on the drill rod, by means of the first few impacts received by the drill rod during its ordinary reciprocation in service. Also'how easily the bit may be again detached vfrom the shank of the drill rod for replacement purposes. This last feature is of course one of the important features of the invention, since bits have to be replaced frequently in mining and similar boring operations, as is at once understood.

As the bits have to be rotated torsionally when in use, the torsional rotation is transferred from the ydrill rod to the bit by means of the shaped sidewalls of the rod and the bit socket.

By means of the bit undercut recesses, depressions, grooves and corrugated surfaces the necesl sary enlargements, bosses, projections and conformations are readily formed on the end of the rod shank, and yetthese deformations are such that the end of the same may readily be withdrawn from the bit, ready for a subsequent use, and for a large number of repetitions of such use.

From which description, as above given, it' is seen that I have provided an exceptionally useful type of detachable drill bit device, which is not lexpensive to manufacture, which requiresv no drill rod of substantially angular cross-section, a bit with a socket of complementary outline to that of the rod, having a number of undercut recesses formed therein between the angular corners of the socket, and a yielding end on the drill rod adapted to engage the undercut recesses and form a holding means for the bit, when the 'drill rod is reciprocated during the drilling operation, and said rod also being adapted to be readily detached from the bit, when itis necessary to place a resharpened or a'new bit on the end of the rod.

2, A drill rod and bit assembly for percussive drilling, said assembly consisting of a bit having cutting teeth lon its lower portion and having its -upper portion shaped to dene a central recess,

open at its upper end and bounded by an upstanding annular Wall and a bottom seat, said wall'having a side recess on its inner face positioned close to said seat, and a drill rod slidably entered in said bit and with an end engaging said seat, said end being formed of a material integral with the rod and arranged deformable upon impact of the end on the seat when the assembly is used in cutting to provide an end edge portion movable into said side recess to hold the rod and bit in assembled relation during the cutting operation, said end edge portion being arranged readily deformable toA facilitate the withdrawal of the rod from the bit at the end of a cutting operation.

3. A drill rod and bitv assembly for percussive drilling, said assembly consisting of a bit having cutting teeth on its lower portion and having its upper por-tion shaped to dene a centralv recess open at its upper end and bounded by an upstanding annular wall and a concave bottom seat, said wall having a side recess on its inner face positioned close to said seat, and a drill rod slidably entered in said bit with its lower end having a marginal portion seated on said-seat, said end being of a material arranged deformable upon impact of the end on the seat' when the assembly is used in ycutting to providean end edge portion movable into said side recess to hold the rod and bit in assembled relation during the cutting operation. Y

4. A drill rod and bit assembly for percussive drilling, said asssembly consisting of a bit having cutting teeth on its lower portion and having its upper -portion shaped to deiine a central recess open at its upper end and bounded by an upstanding annular wall and a bottom seat, said seat being shaped to dene a plurality of upstanding and spaced anvils, said wall having a side recess on its inner face and close to said seat, a drill rod slidably entered in said bit with its lower end engaging said anvils, said end being of a material arranged workable upon said anvils upon impact of said end on said anvils when the assembly is used inA cutting to provide an end edge portion movable into said side recess and a face portion tting between said anvils.

5. A drill rod and bit assemblyfor percussive drilling, said`assembly comprising a bit having cutting teeth on its lower portion and having its upper portion shaped to define a central recess open at its upper end and bounded by an upstanding annular wall and a bottom seat, said wall having a side recess on its inner face positioned close to said seat, means on said seat deining a plurality of spaced anvils each having a curved upper face adapted to engage the bottom end of a drill rod entered in said recess, a drill rod slidably entered in said bit and with its bottom end seated on said anvils, said end being of a material deformable upon. impact of said end on said anvils when the assembly is used in cutting to provide an end edge portion movable into said side recess to hold the rod and bit in assembled .relation during a cutting operation, said end being also deformable to lit between said anvils and resist relative turning of said rod and bit.

6. A drill bit having cutting teeth on its lower portion and having its upper portion shaped to define a central recess open at its upper end and bounded by an upstanding annular wall and a bottom seat, said seat being shaped to define a plurality of spaced and upstanding anvils, and

said wall being provided with a side recess on its inner face and positioned close to said seat. 7. A drill bit having cutting teeth on itslower portion and having its upper portion shaped to deiine a central recess open at its upper end and bounded by an upstanding annular wall and a concave bottom seat, said wall having a single groove only which is positioned close to said seat.

8. A drill rod and bit assembly for percussive drilling, said assembly comprising a bit having a central recess bounded by an upstanding annular wall and a bottom s'eat, a drill rod slidably entered in said recess and having an end seated on said seat, means operable upon impact of said end on said seatv when the assembly is used in cutting to removably connect said bit and said rod in assembled relation, said means comprising a groove formed on the inner face of said wall and close to said seat and integrally formed vmetal at the end of said rod arranged deform- 9. A drill rod and bit assembly for percussive drilling, said assembly `comprising a drill rod and a bit adapted to house an end of said rod, means in said bit defining a seat for the-housed end of the rod, said rod being freely slidable in said bit to engage said seat until said end of the rod is deformed by impact on said seat when the assembly is used in cutting, said end-of said rod being formed of material integral with said rod and deformable under impact, and means in said bit normally out of engagement with said rod and cooperable with said end of said rod when the assembly is used in cutting to engage said end 'and hold said bit and said rod in assembled relation.

` PERCILL LIDDICOAT.