US1160706A - Method of making dental broaches. - Google Patents

Description

. W. W. FOWLER.

METHOD OF MAKING DENTAL BROACHES. APPLICATION FILED MAY 14. 1913. RENEWED APR- 9. I915.

LlfiUfiUfi. Patented NovI-16, 1915.

jm eizhr- COLUMBIA PLANDGRAPH (IO-,WASHXNUTON. D. c.

intrinsic snares Parana cr m WILLIAM w. rownnn, or wnsrnnctron, DISTRICT orcoLUMBIA.

. METHOD OF MAKING DENTAL BROACHES.

Licorice.

Specification of Letters Patent. Patented NQV. 1915.

Original application filed September 24, 191.2,Seria1 No. 722,023. Divided and this application filed lrtay 14, 1913, Serial No. 767,659. Renewedhpril 9, 1915. Serial No. 20,322.

To all whom it may concern:

Be it known that 1, WILLIAM W. Fownnn, a citizen of the United States, residing at l/Vashington. in the District of Columbia, have invented certain new and useful 1m? provements in Methods of Making Dental Breaches, of which the'followingis a specification. x

This invention relates to a novel method of making dental broaches of the type shown in my prior Patent No. 1.067.015, dated July 8, 1918, application No. 722,023, filed September 24., 1912 of which the present application is a division, in which patented structure the prong portion of the broach is universally flexible and flat-twisted to produce a broach which is practically unbreakable and adapted to serve the combined function of a nerve extractor and a canal reainer.

The object of the invention is to provide a method whereby breaches of this type may be easily. effectively and economically produced.

In the accompanving drawing illustrating the invention: Figure 1 is a plan view of'the blank from which the broach is made, showing the same at the completion of the first step of manufacture. Fig. 2 is a transverse section on line 22' of Fig. 1. Fig. 3 is a plan view of the blank as it appears after the completion of the second step. Fig. 4: is a transverse section on the line 44 of Fig. 3. Fig. 5 is a plan view of the blank as it appears after the completion of the third step. Fig. 6 is a transverse section on the line 66 of Fig. 5. Fig. 7 is a view of the completed broach. Fig. 8 is an enlarged detail section on the line 88 of Fig. 7

In carrying my invention into practice I take a piece of round spring-tempered wire of the desired length and gage and shape the butt end 1 in any suitable manner. after which the prong portion 2 is rendered of greater flexibility than the handle or shank portion 3 by tapering said prong portion longitudinall and uniformly toward its pointed extremity as shown. This is accomplished by grinding or filling the prong portion until it accurately fits within a grooved tem'plet or other gaging device whereby accuracy in shaping the prong is insured, the heat generated by the grinding or filing operation also givinga desirable finishing temper.-

The blank produced as above described, and shown in Fig. 1, is then polished and the entering end 4 finally pointed to the desired degree, after which the acting portion of. the prong 2 is flattened as shown at 5 in Figs. 8 and 42.2 This acting portion may be made of any longitudinal extent desired. as a. result of which the flexibility and transverse dimension of said portion is increased in one direction and curved surfaces 6 left at the longitudinal edges of the flattened section. These edges 6 are next ground down to substantially plane surfaces 77, forming at their angles of intersection with the remaining sides ,of the flattened section 5 longitudinal cutting or reaming edges 8. as shown in Figs. 5 and 6. The blank thus'far prepared is then placed in a suitable chuck or holder and by any suitable means turned or rotated to twist the portion 5, as illustrated in Figs. 7 and 9. showing the completed broach, forming a continuous double coil or spiral 9 having continuous longitudinal reaming or cutting edges 10 and 11 and a terminal entering point'12. These cutting or reamingedges are preferably plane'surfaced, in order to prevent the waste of material encountered in forming barbs or spurs thereon, whereby the cost of manufacture is increased on account of the number of defective broaches which must be discarded as unfit for service but under some conditions the reaming edges may be barbed or spurred to meet trade re quirements.

The broach constructed as above described is provided with a spirally-coiled portion which is longitudinally tapered and pointed v and thus adapted to be readily inserted into a root canal, and which is also provided with. cutting edges adapted to ream the wall of the canal and thuh remove all tissue during the rotation of the broach, whereby the nerve will be positively engaged for extraction and the canal at the same time thoroughly cleaned. The portion of the prong between the coiled part 9 and the handle or shank is freely flexible, while the flattened twist of the coiled portion has a wide amplitude of universal fiexibilitv, thus allowing the broach to be bent to dispose the coiled portion at any required working angle without liability of fracture.

The described construction of the twist or coil 9 produces an extracting and reaming surface which has a screw-like action when the broach is rotated in a clockwise direction, thus adapting the vbro'achfor use in penetrating and cleaning out very small canals without the objectionable pressure required in the use of broaches of ordinary construction; "This allows the broach to be fed forward until the end of a canal is reached without liability of its becoming broken 01f within the canal or of being forced through the canal and entering and infecting the toothsocket.

By the use of a fiat-twist the coiled portion, if it should to cause infection or decay.

in prpepee l preierpblp prerirle per p i i a suitable character for indicating the eX- tent-to which the broach may be inserted to reach ,theend' ofthe' root canal of .anaverage tooth, thus enabling a dentist to determme to an approximately accurate degree 1 'ust how far the broach has been" inserted so that he may workwith proper confidence and caution to prevent undue projection of the broach when the indicating means registers with the outer end of the canal or .some other suitable portion of the tooth in connection with which the indicating means is employed as: a gage. To this end, the

upper surface of the broach may be blued or otherwise rendered of contracting color or appearance to the lower surface thereof, such as from the butt end 1 to a point 12 on the prong, the distance of which from the entering point 12 will indicate the distance to which the prong may be safely introduced within a root canal of an average length,

Having thus described my invention, I claim:

"1. The herein described method of making a dental broach, which consists in grinding'or filling a primarily circular spring tempered-blank to form a tapered prong, flattening said tapered prong, reducing the rounded edges of the flattened and tapered prong to plane surfaces, and then twisting said tapered and flattened prong upon itself.

2. The herein described method of making a dental broach, which consists in first tekinp' a circular piece of spring tempered a e I 0 i n r r e p r e pee, prpplrep er. .hhep tee ppe re re te taper from a; point between its ends to one of its extremities, flattening the reduced portion of the wire, grinding or filing the rounded edges of the flattened portion to smooth surfaces, pointing the extremity of said flattened portion, and then twisting said flattened portion upon itself.

In testimony whereof I afiix my signature in presence of two witnesses.

WVILLIAM V. FOWLER. Witnesses E. EnMoNs'roN, J12, C. C. HINES.

Copies of this patent may be obtained forfive cents each, by addressing the Commissioner of Patents,

1 Washington, 13.0.

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