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Publication numberUSRE11118 E
Publication typeGrant
Publication dateOct 28, 1890
Publication numberUS RE11118 E, US RE11118E, US-E-RE11118, USRE11118 E, USRE11118E
InventorsArthur W. Browne
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Dentists burring-tool
US RE11118 E
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)





SPECIFICATION forming part of Reissued Letters Patent No. 11,118, dated October 28, 1890,

OriginalNo. 372,400, dated Hovemboi- 1, 1 887. Application for reissue filed July 3], 1890. Serial No. 360,589- v To all whom it may concern.-

Be it known that I, ARTHUR W. BROWNE, a citizen of the United States, residing at Princes Bay, in the countyof Richmond and 5 State of New. York, have invented certain new and useful Improvements in Dentists Burring-Tools; and I do hereby declare the following to be a full, clear, and exact-description, such as will enable others skilled in the to art to which it appertains to make and use the same. 1

My invention relates to excavating or cavity burrs more especially designed for dentists use. l

r5 Excavating or cavity burrs, as made for dentists use, are intended to cut their way into 'the tooth substance, whether advanced, after the manner of a drill, in the direction of their axis of rotation,.or at an angle to this axis. They ar'e made in a variety of forms and sizes to facilitate the 'excavating of all shapes and sizes of cavities As a large-part of the cutting these tools are used for is done in sensitive dentine, it is extrem el y' desirable 2 that they be constructed to dothe work with the least possiblepain to the patient. To accomplish thisres'ult the burrs must-cut freely without the necessity of crowding them forward to their work and must free themselves vconstantly from chips, as in many cases when cutting in close proximity to a nerve the-least pressure or heat becomes almost unbearable.

It is a fact that the old form of burrs heretofore in use will cut with much less pressure 5 and more'freely when advanced in a linejat right angles to the axisof rotation thanwhen advanced inthe line of its axis. Several rea: sons may be given for this. First. The teeth or leaves of the burr al 40- coming togetherat the end of the axis there is no cutting-edge at this point. In factit has usually been the practice to put a small cut across the extreme end of the burr, in which case, on using the end of the burrs, 5 there is a small projection of the material operated in which cannot be cut by the burr,

and which must break awayin order to allow,

the tool to advance.

Second. In advancing the burr in the line of its axis every tooth or leaf-and there are usually eight-will be constantly cutting,

while if advanced at right angles to its axis two, or at inost three, teeth are all that can be brought into action at any one time. It of. course requires four timesiasmuch-press'ure to make eight cutting-edgesof a given length penetrate the material as would be necessary to make two teeth of the same length take a like cut.

Third. It is a fact that in the old form of burr the spaces between the teeth or leaves near the end of the axis ofthe burr are much narrower and the cuts shallower than at any other portion, so that there is little room for chips. This is due to the fact that as the leaves or edges all come together 's'ubstantially at this axis the intermediate spaces vanish not only circumferentially (or in their width) but radially (or in their depth) also,

and thus little or nojclearance is aflz'orded at or near the axis. In the case ofa's'imple burr intended for lateral enlargement of a hole already formed, such end clearance fills no important function; but whereforward drilling is attempted with such-burrs I find in'75 practice that the chipsdohot' get away from the cutting-edge freely enough to prevent the spaces from choking,- when of course there is great heatdeveloped from the resulting friction and very little cutting is accomplished.

The object of my present invent-ion is to provide an improved burring-tool in which the objections to and imperfections in the old style of burr, noted above, will be avoided;

The improvements made by me will firstbe described, with the aid of the accompanying drawings, sufiiciently in detail to enable them to be clearly understood. I will then distinctly recitethe subj cot-matter. claimed herein as my invention at the close of this specification.

In said drawings, Figure 1 is a view of my improved burring-tools,with the shankthereof having a flattened transversely-grooved driving end to adapt it to the rotary tool-carrier 5 of a dental-engine hand-piece, such. as are in common use. Fig. 2 is a view of the front end of the improved burr, and Fig. 3 is a similar view of'the front end of a burr of the old style. Fig. 4 is a similar View of another form of myimproved burr. Figs.5 and 6 are respectively cross-sections of the burr shown ICC.

-much less pressure than is required by the in Figs. 2 and 3, and Fig. 7 is a side elevation of the burr-head shown in Fig. 4. 1

The shank A of my improved burring-tool may be of any desired or practicable form to adapt it to the carrier'which is to rotate it.

My invention has'relatiou only to the work ing end or head 13 of the tool, which may be substantially round-a shape commonlyemployed-or ofother form. Twoof the oppo.- site cutting blades or leaves b of the burrhead are or may be substantially continuous, as clearly shown in Fig. 2, meeting at the extremity of thetaxis of rotation and forming a single long cutting or drilling edge or blade, while upon either side thereof the other cutting or burring leaves or edges 1) are brought together in groups, as clearly shown outside the axis of rotation. As the terminal or vanishing points of these edges b are not immediately adjacent to the axis there is no difliculty in providing a clearance of very considerable depth on each side of the drillingedge where-it crosses the axis. At their near est approach to the axis such clearance-spaces are preferably somewhat less in depth than the radial distance from the-axis to the vanishing points of the burr-edges b, and they increase in capacity from said points until they reach their greatest distance from the axis. Thus they will be suflicient to permit the retreat of the chips as the v drill-edge advances. There is therefore asingle drill or cutting-edge at the axis of the burr and the burr will, in operation, advance in this direction as readily as will a drill, which it practically is, while the large deep cuts or clearance-spaces upon either side allow the chips to pass back almost in straight'lines, so as to free the burr as rapidly as the chips are out, It is also evidentthat when advancing in the direction of its axis, or drilling, there will be a much less total length of cutting-edge in operation than in the old form. In practice I have found that myim proved burr will cut on the end or drill with very old form of burr and will advance, throwing the chips behind it, more rapidly and with out generating appreciable heat. In opening a cavity in a tooth, for example, it has been the custom with careful operator's, owing to the difficulties referred to, first to penetrate to the depth necessary with a drill and then,

having exchanged the drill for a burn, toenlarge the cavity to the required dimensions. With my improved burr-drill this change of tools will be unnecessary, as the burr will perform the offioe of the drill in a superior manner, as well as do what has heretofore been thought to be its own proper work.

In Figs. 4 and 7I have shown a form of my improved burr-drill diifering from that of Figs. 1 and 2. The form shown in Figs. 4 and 7 has the single cutting or drillingedge b at the extremity of the axis of the burr; but said edge is shorter than in "theform shown in Fig. 2, an annular groove 0 being cut around the crown or body of the burr, so as to form the front projecting ends of the side leaves or teeth vb, virtually a circular cu tting-edge in rear of the front drilling-edge of the burr.

.I am aware that in certain forms of nonexcavatingburrs-suoh, for instance, as I the cherry, usedto smooth out cavities 'of bullet-mold's-'it has been customary to form a series of edges crossing the front end of the burr in continuity but at random or without symmetrical relation to its axis, and I therefore do not intend to include instruments of this character in my claim, hereinafter made.

Such cherries, however, not being intended to drill, were not provided with clearancespaces of the character I have above described, nor were they provided with the single drilledge proper, intersecting the axis of rotation,

which characterizes my invention,and so far as excavation was concerned possessed no advantages over the form of burr which I have shown in Fig. Ideem it unnecessary to illustrate or describe other forms of my improved burr-drill, and therefore, without further elaboration,

I claim- The burr-drill consisting of the lateral burredges, in combination with the single drilledge crossing the axis of rotation of the tool and formed with clearance-spaces, substandrill-edge andsaid burr-edges.

In testimonywhereof I have afiixed my sig- .tially of the character set forth, between said I nature in the presence of two witnesses.


Witnesses; v


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US6491520 *Apr 23, 2001Dec 10, 2002Mediteam Dental AbDental instrument