US 2222517 A
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Nov. 19, 1940. J. w. PRECE FRACTURE NAIL AND MACHINE FOR MAKING SAME Filed Dec. 8, 1958 3 Sheets-Sheet l Nov. 19', 1940. J. w. PRICE FRACTURE NAIL AND MACHINE FOR MAKING SAME s Shets-Sheet 2 Filed Dec. 8, 1938 Nov. 19, 1940.
J. W. PRICE FRACTURE NAIL AND MACHINE FOR MAKING SAME Filed Dec. 8, 1958 3 Sheets-Sheet 3 Patented Nov. 1 9, 1940 AND momma FOR mxmc sum FBACTURE NAIL PATENT. orifice James W. Price, Roanoke, Va; Application December 8, 1938, Serial No. 244,690
This invention is-an improvement in fracture nail-s and machines for making same.
Nails employed for holding the neck of a fractured thigh bone together have been employed comprising a counterbored cylindrical longitudinal center with a number of more or less sharpened ridges radiating therefrom in angular relation to each other, so that a cross-section. of the nail has the shape of a three-pointed starfthe purpose of which are to find their way through the broken parts of the bone, when driven therethrough. i
There are certain diiliculties encountered in the vmanufacture 01' such a nail, and chief among them is the impracticability of drilling the relatively small hole accurately and uniformly except perhaps in a very short nail longitudinally through the cylindrical center, as ithas been found practically impossible to drill such a hole through a nail more than four inches in length, and even then the drilling usually has to be from opposite ends toward the center until the ends meet somewhere near the center of the nail, all of which requires great accuracy.
In my present invention, I have sought to overcome and have satisfactorily obviated this difliculty by entirely dispensing with the drilling of the hole through the center of the nail, and in lieu thereof cutting a groove throughout the length of the cylindrical center, with a convex cutter having a radius equal to the radius of the usual guide-wire or borer employed in th'se operations, and out to a. depth which allows the wire to lie in a plane concentric with the diameter of the nail. This groove may intersect the drilled and threaded head of the nail, thereby permitting the use of a suitable driver with a hole drilled through its center to receive the outer end of the wire as the nail is driven into the parts of the bone.
In addition to the foregoing advantages, there are others which might be recited.
In my improved nail, there is no air space or pocket as is the case with the drilled or cannuprove detrimental to the formation of new bone.
' In my invention, the guiding-wire may be of larger size than heretofore, thus preventing bending during its insertion without necessarily enlarging the nail itself. 2
My nail can be made at less cost than drilled or cannulated nails and it has the advantage of compensating for any slight bend in the guide wire as the open side of the groove better allows the wire to adjust itself as the nail itself is being driven, thereby minimizing the possibility of the nail skidding up in case it strikes a burr on the guide wire, and in consequence driving the wire along as the nail is driven. This is an important effectiveness of the threaded head, as the detach able driver serves as a partial guide and will work equally as well as witha solid head, which would mean the groove might extend throughout the entire length of the nail, and, to repeat, without detracting from its efllciency, and still leave enough thread in the head for the attachment of the driver or an extractor screw. v
The foregoingvmight be summarized and amplified as follows:'
First: The instrument is simpler to manufacture, for by milling the groove and flanges of the nailat the same time, one machining operation is entirely eliminated, namely the'drilling of a hole which is a very diflicult operation as heretofore pointed out, and necessarily limits the length of the nail to about four inches, this being about the maximum length that it is practicable to drill such a small hole, whereas by milling the is the case with a drilled nail.
Third: The guide wire employed may be larger and sufliciently large to prevent its bending during insertion, althoughthe nail with a larger size guide wire does not displace any appreciably greater amount of bone; in other words. the new bone growth will be nearer to a solid formation due to the lesser displacement resulting from the use of my improved grooved nail, since when the guide wire is removed, new bone forms in the groove, as well as between the flanges of the nail, which advantage is wholly lacking in the drilled nail due to the presence of the shell of steel around the hole.
Fourth: My improved grooved nail has the advantage of compensating for any deflection of the guide wire as the open side of the groove better allows the wire to adjust itself as the nail is being driven, thereby minimizing the possibility of the edge of the hole in the nail skidding up a' burr on the guide wire and driving the wire along with the nail as the nail is driven, which is important as previously pointed out. a 1
Fifth: The sterilization of a grooved nail is rendered safer and more complete as the groove is polished and easier and more effectively cleaned than is possible with a relatively small hole, and
the polishing of the groove also makes the nail Fig. 6 is a fragmentary plan view of the ma- 8-8 of Fig. 5.-
F18. '7 is a section on-the line looking in the direction of the arrows; and
Fig. 8 is a section on line 1-1 of Fig. 5, looking in the direction of the arrows.
Referring more particularly to Figs. 1- to 4, the
numeral I represents the nail; and 2, the flanges, which are preferably arranged equidistantly as shown in Fig. 2, .andthese have slightly sharpened ends and edges 3.
The numeral 4 indicates the groove cut through the longitudinal cylindrical center 5.
The numeral 6 is the driver having a counterbored longitudinal center I to aflord clearance for the wire 8. The head 9 of the nail has in-. ternal screw-threads III, and into these threads.
the threaded end II of the driver is adapted to be removably screwed.
To facilitate turning the driver 6, it-is provided with holes l2 to receive some instrument for turning it (not shown).
In the use of the nail the wire 8 (sometimes called a borer) is first .drilled through the fractured thigh bone shown in dotted lines in Fig. 4, after which the outer end of the wire is inserted in the groove in the longitudinal center of the nail, or in the bore of the driver, and the nail is then driven through the fractured parts with the wire as a guide. After the nail is in place, the driver 6 is removed, also the wire 8.
As previously pointed out, the groove 4 is formed by means of a cutter in lieu of a hole bored through the longitudinal center of the nail. The letter C represents this formed cutter'as shown in Figs. 5, 6 and 7. This cutter is keyed on a suitable shaft l3. The nail is clamped between two jaws and I5, and the latter is movable with respect to the former, and the two jaws combinedly form a rounded socket l6 conforming in shape to, and adapted to, receive and clamp the nail therein as shown in Figs. '7 and 8. The movable jaw I is slidably connected with the jig base of the jaw l4 and may be guided and held in position by pins l1, and set-screws IB-turn in threaded holes 20 in the lugs l9, upsetting from the base of the movable jaw l5, and impinge the back of the movable jaw l5 as shown in Figs. 5 to 8, and by turning. these screws I8 to the right, the nail is clamped and held rigidly in place between the two jaws.
The jaw I4 is adjustably connected with the machine table 2| by means of a table-bolt 22, the head 23 of'which is located in-a groove 24 in the machine table 2|; and after the jaw I4 is suitably adjusted with respect to the machine table 2|, the nut 25 .on the upper end of the table bolt 22 is tightened to secure the part rigidly together, as shown in Figs. 5 and 6.
The machine table 2| has a dove-tailed sliding connection with the machine bed 26, which forms a trackway for the sliding and feeding movement of the machine table 2| and the parts connected therewith, including the nail I which is being held by the clamps and fashioned by the cutter C.
A stop-screw 21 turning in the lug 28 on one end of the jaw l4 bears against the head 9 of the nail during the cutting operation, and resists any tendency of the nail to slip endwise between the clamping jaws, and this stop screw 21 cooperates with the jaws to securely hold the nail during the cutting operation.
While the grooving cutter only is shown in Figs. 5, 6 and I, obviously this grooving cutter may be replaced by other cutters to cut the radiating flanges 8 and the cylindrical center of the nail from which these flanges radiate.
A spacing plate 30 is employed for gauging the nail as shown in Fig. '1 to insure precision in the cutting of the groove 4 in the nail.
In a nail thus constructed and a machine as described and shown, substantially .the entire process is strictly a cutting operation as distinguished from a cutting and boring method as hitherto practiced with the obvious results and advantages hereinbefore set forth.
The method of operation of the machine and the cutting of the nail is as follows: After milling the flanges 3 on two sides of the nail, the formed cutter C is inserted in a tapered hole (not shown) in the shaft I3 of the milling machine. The flanges 3 are properly set by removing the spacing plate 30 and loosening the movable clamp screws 8, then turning the nail in the jig until one side of a flange 3 comes in line with the spacing plate slot in which the spacing plate 30 is held. The spacing plate 30 is then inserted in the slot, and the clamp screws l8 and the stopscrew 21 are tightened up, thus holding the nail rigidly in the position shown in Figs. 6, '7 and 8.
1. A fracture nail having a longitudinally grooved center and flanges radiation from said center, in combination with a driver detachably secured to one end of the nail, the driver counterbored through the longitudinal center in alignment with the longitudinal center of the nail, and a wire adapted to be received through the center of the nail and driver.
2. A three-flanged fracture nail having a channel-shaped core, the flanges of which radiate from the channel-shaped core, one flange extending radially from each edge of the channel, and the third one from the back of the channel.
3. A three-flanged fracture nail having a channel-shaped core, the flanges of which radiate from the channel-shaped core, one flange extending radially from each edge of the channel, and the third one from the back of the channel, the longitudinal center line of the channel and the center "of the flanged peripheries being approximately concentric.
4. A fracture nail including a channel-shaped core having a plurality of radial flanges which extend outwardly from the outside of the channel-shaped core, the latter being concentric with the central longitudinal axis of the nail.
5. A fracture nail including a channel-shaped core approximately semi-circular in cross-section, and having a plurality of flanges radiating from the outer surface of this channel-shaped core.
' JAMES W. PRICE.