USRE23539E - Drill bit - Google Patents

Description

8 26, .1952 v c. v. TILDEN Re. 23,539

. DRILL BIT Original Filed Sept. 20, 1947 11 10 v 12 I V r I INVENTOR.

Reissued Aug. 26, 1952 UNIT E D S TAT ES; PATE- NT F F ICE DRILL BIT Carl'V'. Tilden, Altadena, Calif;

originalnNo; 2,506,474; dated Mayz, 1950, Serial No. 775,186,- September 20,1947.

Application for reissue- Aprilc30, 1951, SeriaLNo..223,69.3.

12' Claims.--'

Matter 'enclosedin-"heavy, brackets Iappears in-theo1-iginal:.patent...but.forms no. partot this! reissue specification; matter printed in .italics 'indicates vthe additionsmade by reissue;

1; My invention relatesgenerally to' rotary bits: and particularly to bits for drilling holes in hard.

granular, structures such, as brick, concrete, and

other masonry formedjof' aggregate and binding. material.

More particularly my, invention has reference todrillbits of the type. having a solidj body with a disc-shaped, head of concentric external circumfere'nce fixed on one endofthe body concentrically to theaxis. of rotation thereof ;'v teeth set radially in the face of the head. andperpendicular.

to the axis of rotation; and withor without a. screw thread or anger on theexterior. of the body for removing material cuttings from. the-hole being drilled.

Bits of this character as heretofore proposed have a low drilling efiiciency. for thereason that as drilling proceeds in ahole-the drill' is not.re-,

11eved..of the material cuttings with sufiicient rapidityto prevent accumulation thereof inthe hole. As aconsequence, the accumulated. cut.- tings offer considerable. resistance to rotation of. theqdrill; and hence, impede. its drilling action, thus requiring, more time and power than .isactually necessary to drilla hole of any. given depth.

Accordingly, it is a purpose of. my invention to provide a drill bit of this typer'which is char.- acterized functionally by it's. ability when drilling. a hole in masonry tocontinuouslyand completely, remove the material cut..from-th'e cuttinglfacev of the bit, as well asf'rom the hole, in am-annerto continuously'relieve the bit and hole of the-cut material, andto thus accelerate the.drillir'lg.ace tion ofthe' bit to the extent of greatly reducing the power and time requiredto drill, a. hole. of any given depth.

It'is'. also a purpose ofmy invention tovprovid'e a drill bit which'embodies dual means for conveying the material from the hole cut by the bit, oneof these means. being exterior and the other interior. to thebody of the bit, with the two means joining at a: point spaced from the cutting face ina mannerin which they may further reduce Fig; 2-is an end view of the dri-ll bit', showing the cutting face-thereof.

Fig. 3 is a longitudinal sectional view-*on the line[s ]"33 of Fig. 2-illustrativeof'the drilling actionof the drill bit irra masonry structure:

Fig. 4" is across-sectional view taken-onthe- 1ineEs] -4'4'of*Fig. 1-.

Fig. 5-is an elevational-view, similar-to Fig. 1;

but withthe -drill bit rotated ninetydegrees toillustrate the slot communicating betw-eenthe=e-xterior of the bit and the-interior-thereofv Having specific reference to. the drawings, this embodiment of my invention-comprises an elongatedbodyl0= of circular cross-section having anaxial [bore H.- trailing or proximal endof the body l0, by;- a shank" l2 securedthereto, sothatthe bore-forms apassage, pocket or'recess; The leading'or distal end of the-body 'l0 is enlarged-toform an annu lar'head' l3, and the face --l4 -thereofhas teeth I5 set: therein. The teeth l5; of which there-may;

befour or any othersuitable number, arewpref erably made of--cemented carbide,- and are dispos ed-in-acirclearound the borel 1', so that their cutting edges, which are the leading edges upow rotation, are approximatelyradial tothe head I 3;

while their outer ends project outwardly from=the=- periphery-of thehead, and their inner ends project-into the bore- I I, as best-illustrated -'in- Fig-,- 23' The individual teeth-are shaped at their cutting ends by havingtheir-corners cut 017 cum-angle to provide-in each instance-cutting edge po'rtions which lie respectively in a-plane-normal' tO-th a longitudinal axis-ofthe body and 'implanes'which diverge from-anintersecting line located forward of the-drill end. This shaped) the-ends o'fthe;

teeth is clearly shown-inthe drawing and causes a circular channel having outwardly lemming -side wallsto be formed as-thedrillend-rotates-in-con--- tactwith the material being-drilled; The sloping sidewalls ofthe =holeper-,for-md drillcentering function in an obvioustmanner.

A'spiral threadl 1 isprovidedon theoutersur faceof the bodyl0, formingan auger for carrying away cuttingsin the form of granules-of 'the' 1 material beingdrilled Thethread l l is preferably of square cross-section, in the-manner of a:

SellersSquare thread; and extends-froma point near the -head l 3 to .Ith'e proximal end of the body ID.- Between the distalend'of the thread H and the head l3; the body;Hi-isreduceddn'size'to its" diameter at the bottom of the grooves Haof-the:-- thread,- so i as to leave-an annular groove-l 8 adjacent tothe head; The periphery-ofthelheadi I3. is flattened, as-at l-9- (see- Fig=.- 5), to' -fornr shallow channels or clearances in-advance:- off 3 each of the teeth I5, leading from the face I4 to the annular groove I8 when the bit is inserted in a hole, and through which finely comminuted particles may pass between the outer ends of theteeth I to the groove [8, and thence to the auger thread H.

A slot 2| is formed in and extends longitudinally of the body In from a point where it intersects the annular groove IE to a point a few threads distant from the proximal end of the body 10. The slot 2| communicates with the bore II and interrupts the threads of the auger thread H where it intersects them, providing a passage for granular material and chips from the bore I I to the auger thread along the major part-of the latter. A shallow longitudinal groove 22 extends from and in continuation of the slot 2|, to the proximal end of the body I0, providing a passage supplementary to the slot or to that passage provided by the auger thread I! by which the drilledout material may reach the zone around the shank I2.

In the operation of drilling a hole in masonry structures, the teeth I 5 will cut an annular channel therein, tending to form a central core in the leading end of the bore I I, but because the inner ends of the teeth project into the bore II they operate to grind up the core as it is formed. Because the outer ends of the teeth I 5 project slightly beyond the periphery of, the head I3, the hole will be slightly oversize and will not bind upon the bit as the bit progresses inwardly.

Finely comminuted materials, cut from the face of the hole by the teeth I5, will move through the clearances I9 to the annular groove I8 and thence to the auger thread groove Hat by which it is removed from the hole. [Those] Some of the particles of the material dislodged at the face of the hole will enter the bore II through the open end thereof between the inner ends of the teeth I5 to be subjected to the grinding action of the teeth in the disintegration of the core as it is formed If, and thus the]. The core is broken up as rapidly as it is formed [to offer] and oflers no impediment to the free flow of the material in the bore.

The slot 2| permits the material to be thrown by centrifugal force outwardly of the side of the bit at that part of the slot projecting from the hole, either when drilling horizontally or downward. When drilling upward the exposed part of the slot allows the material to gravitate from the bit aided, of course, by centrifugal force.

At that part of the bit within the hole, the slot 2| permits the immediate discharge to the auger thread ll of a part of the material suited in size to passage along the thread. If too large to enter the auger thread they are immediately ground against the wall of the hole and battered by the sides of the slot until suitably comminuted. The sharp inner and outer edges of the slot 2| assist materially in rendering this battering action effective. The Sellers Square thread I1 is also of assistance in this respect, presenting fiat radial surfaces and substantially rectangular corners at its intersections with the slot 2|, well adapted to batter and grind material passing through the intersections without injury to the thread.

Material entering the auger thread I1 is rapidly conveyed to the face of the masonry structure or, if the entire body of the bit has entered the hole,

to the zone around the shank l2. The groove 22,-

at its points of intersection with the thread I'I, provides additional sharp edges by which any large particles that may have travelled to the 4 outer end of the bore I l before emerging through the slot 2|-as for example when the hole being drilled is directed or inclined upwardlymay be further comminuted. Thus the drill will free the hole of all loose material, of eitherchip or granular size.

Manifestly, a bit constructed in accordance with my invention provides one exterior passage means for conveying the material cut by the teeth to a point exteriorly of the hole, which comprises the auger I1, and an interior passage means for conveying the material cut likewise to a point exteriorly of the hole, which comprises the bore or recess I I and the slot 2|. These two means coact one with the other to constantly relieve the teeth of the cuttings; to reduce the cuttings to sizes which can freely pass out of the groove IIa, or out of the interior of the bit through the slot 2|; and to utilize the rotary motion of the bit to impel the cuttings into both the groove Na and the slot 2|, and thus cause the cuttings to emerge from the hole from points interiorly and 'exteriorly of the bit simultaneously. Thus the bit operates to establish and maintain a constant flow of the loose material out of the hole to reduce [its] resistance to rotation [of the bit,] and to [thereby] increase the speed with which a hole may .be drilled [by the bit].

Although I have herein shown and described only one form of drill bit embodying my invention, it is to be understood that various changes and modifications may be made therein without departing from the spirit of my invention and the spirit and scope of the appended claims.

I claim:

1. A rotary bit for drilling concrete, including: an elongate, cylindrical body having an axial bore and formed at the trailing end with means for connection with a rotatin tool; said body being enlarged at the leading end thereof to form an annular head of greater diameter than said body. said head being provided in the face thereof with teeth disposed on a plurality of equally angularly spaced radii, the body being provided on the outer surface thereof with a spiral thread forming an auger and with a single slot extending transversely through said thread, said slot commencing at a point adjacent the leading end of and extending longitudinally of and terminating at a point spaced from the trailing end of the body, said slot establishing communication between said bore and the exterior of said'body and said slot providing a lateral outlet for the material released within the area defined by said teeth during rotation thereof.

7 2. A rotary bit for drilling concrete, including: an elongate, cylindrical body having an axial bore and formed at the trailing end with means for connection with a-rotating tool; said body. being enlarged at the leading end thereof to form an annular head of greater diameter than saidbo'dy,"

said head being provided in the face thereof with teeth disposed on a plurality of equally angularly spaced radii and having their outer endsprojecting outwardly from the periphery of the head and their inner ends projecting into the bore of said body, the body being provided on the outer slot meaning a la eral outlet tenths mate ial rel i hin the ar a d f ned y "sa eeth (131F115 Q aii ihsrsq 3- i l-ro ar it ior dri ling mmie inclu in a el ga e s sii i a lr b re y indr ca bo levies tim i n a d t eo a. r m vab e l emsa s s mi isinse too f r ta in a bdr; sa il-havin e la d hea a ror removal from the hole; and said body having a'long'itudinal linear slot extending between the.

'leadin'g'endand trailing end and communicating with the exterior of said body-for conveying detrital material lnteriorly along and laterally outward of said body toa point beyond the material being drilled.

4. A rotary bit for drilling concrete, including:

an elongate,cylindrical body having an axial boie and'formed at the trailing end with means for connection with a rotating tool; said body being provided in the face of the leading end thereof with teeth disposed on a plurality of angularly spaced radii and having their outer ends projecting outwardly from the periphery of the body and their inner ends projecting into the bore of said body, the body being provided on the outer surface thereof with a spiral thread forming an auger and with a single slot extending transversely through said thread and longitudinally of the body and establishing communication between said bore and the exterior of said body, said slot providing a lateral outlet for the material released within the area defined by said teeth during rotation thereof.

5. A rotary bit for drilling concrete, including: an elongate, cylindrical body having an axial bore and formed at the trailing end with means for connection with a rotating tool; said body being provided in the face of the leading end thereof with teeth disposed on a plurality of equally angularly spaced radii and having their outer ends projecting outwardly from the periphery of the body and their inner ends projecting into the bore of said body, the body being provided on the outer surface thereof with a spiral thread forming an auger and with a single slot extending transversely through said thread, said slot commencing at a point adjacent the leading end of and extending longitudinally of and terminating at a point spaced from the trailing end of the body, said slot establishing communication between said bore and the exterior of said body, and said slot providing a lateral outlet for the material released within the area defined by said teeth during rotation thereof.

6. A rotary bit for drilling concrete and the like including an elongated cylindrical body provided interiorly with a bore extending its full length and formed exteriorly with a spiral thread, arouately spaced teeth extending substantially radially in one end face of said body, the ends of said teeth projecting radially slightly beyond the thread on said body and also extending radially s i htly ete said 12 s a. el n ated sl mans l iw iudi ial u .ofaid bod inter thre and ponnss nas l he ew ofs dbcd qnde' ank ela li h wdvf i y imedefr 1 F i 7. A' rotary bit-for drilling concrete and the ik in l a n ate e l aii sel b9 114 a n a head en an are and s by tsn riiw n d' w said wil br ins I d ie i i/ ea er s n s ith? r ml'th whi hen" its d n ar s s id ha e was perpendicularly 'to 'tjheiloiigitudinal axis ojfsaid some"? b -i" in any n i dinal-1 h r urpo tino s elf, a jcuately .sme i extending su s i ly a ia ice sir-me or a odfl! h w s mil t h ma sin radially slightly beyond the thread on'f said body and also extending radially slightly into said bore, n el n 1? m nd lon tud nal y Q said body intersecting said thread and connecting said bor with the exterior of said body, anda shank extending rigidly from the end of said body spaced from said teeth.

A rotary bit for drilling concrete and the like including an elon ated cylindrical body It inga head'end and as'paced shank end, ri d abrasion-resistant teeth at the head end of said body extending radially slightly beyond said body ,for the purpose, said body being rotated, of cutting a hole into which said body can ep-f' tend, said body including means to feed particles from said head and toward said shanh end ,Q mprising a longitudinal bore extended through said body, a spiral thread encircling said body the conooluiions of said thread forming a groove, and a linear slot in the wall of said body through which particles can pass connecting said bore to the groove spacing the convolutions of said thread, and a shank extended longitudinally from the shank end of said body adapted to receive a rotating force.

9. A rotary hit for drilling concrete and the like including a rotatable cylindrical body having a forward end and a trailing end and formed with a longitudinal bore, a plurality of cutting elements fixedly carried by the forward end of said body and extended radially inwardly and outwardly therein for the purpose of cutting a channel in a contacted material as said body rotates in contact therewith under pressure and into which channel said body can advance as said channel deepens, the inward radial extensions of said cut ting elements being adapted to oomminute a core formed in said material inside said channel, a Zen. gitudinal slot in said body opening into said bore and through which pieces of said core can be thrown centrifugally, and a multiplicity of cutting edges positioned along said slot formed by the intersection therewith of a spiral thread encircling said body, said cutting edges being adapted further to oomminuie pieces of material thrown through said slot from said bore.

10. A rotary bit for drilling concrete and the like including an elongated cylindrical body provided interiorly with a bore extending its full length and formed erteriorly with a spiral thread, arcuately spaced teeth extending substantially radially in one end face of said body and formed individually at their cutting ends with sloping, forwardly converging, inner and outer corner portions radially spaced by a central portion lying in a plane substantially normal to rotational axis of said body, the radially spaced ends of said teeth projecting radially slightly beyond the thread on said body and also extending radially slightly into said bore, an elongated slot extended longitudinally of said body intersecting said thread and connecting said bore with the exterior of said body, and a shank extending rigidly from the end of said body spaced from said teeth.

11. A rotary bit ,for drilling concrete and the like including an elongated cylindrical body provided interiorly with a bore extending its full length and formed exteriorly with a spiral thread, arcuately spaced teeth extending substantially radially in one end face of said body, the ends of said teeth projecting radially slightly beyond the thread on said body and also extending radially slightly into said bore, an elongated slot extended longitudinally of said body intersecting said thread and connecting said bore with the interior of said body, a groove in the exterior of said body intersecting said thread and forming a continuation of said slot, and a shank exteniding rigidly from the end of said body spaced from said teeth. 12. A rotary bit for drilling concrete and the like including an elongated cylindrical body haping a head end and .a spaced shank end, rigid abrasion-resistant teeth at the head end of said body extending radially for the purpose of cutting a hole into which said body can advance upon said body being rotated about its longitudinal axis, said body including means to feed material displaced by said teeth from said head end toward said shank end comprising a longitudinal bore in said body, a spiral thread encircling said body the con'volntions of said thread forming a groove, and

an opening in said body intersecting at least one turn of said thread and having anarea of'the magnitude of the cross-sectional area of said bore, said opening providing'a discharge for material from the interior of said body to the exterior thereof where said material can be displaced by said thread in the rotation of said drill, and a shank extended longitudinally from the shank end of said body adapted to receive a rotating force.

1 CARL V. TILDEN.

REFERENCES orrED UNITED STATES PATENTS Number Name Date 52,632 Whittlesey Feb. 13, 186.6 218,374 Fishburn Aug. 12, 1.876 418,903 Weiss Jan. 7, 1890 483,210 Corrigan Sept. 27, 1892 799,880 ,To'nge Sept. 19,1905 831,056 Gilmore Sept. 18, 1906 1,484,352 Izard Feb. 19, 1924 1,512,841 Gamble Oct. 21, 1924 1,846,177 Bascom et a1 Feb. 23, 1932 2,188,631 Kraus Jan. 30, 1940 2,308,042 Barnett Jan. 12, 1943 2,425,132 Stokes Aug.v5, 1947 2,524,570 Phipps Oct. 3, 1950 2,567,084 Stokes Sept. 4, 1951

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