US2442436A - Dermatome - Google Patents

Description

June 1, 4948,. J, D REESE 2,442,436

DERMATOME Filed 001'.. 25, 1945 lo i.

MESZ/571,50

no INVENToR. f' JEM LD. EEE-.5a

Patented June 1, 1948 UNH??? `ST.- '17555 an expendable blade.`v

".While'the improvements of the present invention lmay V-be incorporated in various'types oi dermatomes, they are yof particularadvantage in the type comprising a body 'member having aV convexfsurface, a-pair of" posts at opposite sides 'of the body member, blade-supporting structure carried by one end oi the posts, and means supporting the posts at their other ends from-'the body member for movement of the blade parallel to, andA at a predetermined distance froni,the body memberconvexfsu'iace.

f Infpii'ordermatomes ofi/this type, it 'hasbeen customary to use 'a relatively expensive lblade andtoresharpenand rehone the blade' whenever necessary,fusually after cutting a" half dozen grafts or less. Whilefto one who hasne'ver'- out a` "graft with a dermatome, it 'might seem 'that such' abla'dev should cut alarge number ofgrafts before requiring'fresharpening, itsl'io'uld be realizedthat,fin"'cuttinga'fnorinal graft, the blade splits 'a piece ofl skin approximately Vfour linches! wide 'andl eight inchesl`lbn"g`,' a 'directionparallel to' the surface of the skin.' -fThis is' theequivalent'of a scalp'el makingin'cisions' 'whichftotal over ``130 feet. 'It is 'a inatterof'siinple 'arithe metic th'at,"in cutting six"grafts (the'normal life of a dermatome blade for ione' sharpening), the bladef does the" equivalent cutting; 'of a fsc'alpel making-over 750 incisions each a foot in length". Obviously', frequent resharpening f of these blades is:necessary. -'Ihisffrequent resharpening produces a iurther problem in thateachy resharpening moves the cutting edge of the bladeback affew thousandths oan-inch, and what is worse, it usually moves'it back more at one endoi the blade than atftheother. As a result,- it is necessaryfor the operator to reset or lreadjust the blade-supporting structure relative tothe body member and its convex surface, to obtaina graft Grundform thickness. Y

- 2 @eine (ci. '12s-305.75).

A solution to this problem is offered in applicants vcopending application, Serial No; 618,- zxyfiled September` 2,5; 1945, wherein there-is disclosed' a dermatome whose posts are longitudinally adjustableeach independently of the other, to take care oi changes in the blade-cut'- ting edge, resulting from resharpening.v ln addition, the blade-'carrying bar can be adjusted toward and away from the 'posts by whichit'is supported, to vary the thickness ofthe graft to be cut.

The present invention provides a greatly simplified solution to this problem by providing an expendable blade, so that no resharpening is required, and the means for longitudinally adjusting each'post independently of the'other (disclosed in applicants `copending supra) can be omitted.

In order to render a dermatome blade expendable, a minimum ofthe necessary high grade steel must be used;which resultsina relatively exible blade, requiring special holding means. An object of the present invention isto provide such a blade holder.

Ifhese'and other objects are efiected by the invention as will be apparent from' the following description and claims taken in accordance with the accompanying drawings, iormingia part of this application, in which: f

Fig. l is a front elevational view of a dermatome embodying the novel features ofr the present invention;

Fig. 2 is a side elevational view of the lefthand end off-Fig. 1, with a portion thereoi in section; 5

Fig. 3 is an enlarged exploded view of the sectionedportion 'of Fig. 2;`

'Eig liis a sectional view, taken along the line IV-LV oirliig. V3,; looking in "the direction indicated by the arrows;

Eig. 5 is a sectional view, taken along the line V-Y of Figpi, lookingl in the direction indicated by thearrows;

Fig. 6 is a 4bottom plan view oi a modified form of blade holder andblade;

' Fig. 7 is a vsectional view, taken along` the line virvn of Fig. o; looking in the direction indi cated lby the arrowsyand Fig. 8 isa plan view oi one of the spacing shirnsys'hown in Figs. 2 andr3. A f Referring now to the drawings more in detail, the reference character Iii indicates, inY its entiretyya dermatorne comprising -a body meinbei." il consisting of a pair'oi sen ii-cylindricaljl side 'Walls l2. 'joined along theirY @iin/ed. edges., in. a,

application,

3 concave-convex wall I3 having an outer convex surface I4. The opposed side walls I2 carry a handle I5 bridging the space therebetween and by which the operator may rock the body member II on the donor area of the patients body. The handle I5 has a bore I6 therethrough constituting a bearing in which is journaled a shaft I'I for rotary and reciprocatcry movement relative to the body member.

The shaft I1 carries on its terminal portions a pair of posts I8 and I3. Preferably, both posts are threaded on the terminal portions of the shaft II, the post I 8 being secured by a pin 26 and the post I9 being adjustably fastened by a set screw 2|.

Inasmuch as the posts I8 and I9 are identical except that the latter carries a handle 22, by which the shaft, posts and associated bladesupporting structure may be reciprocated relative to the body member, the structure of only one post will be described in detail. Each post comprises an arm portion 25, preferably solid in section, extending radially of the shaft il and provided at its free end with a head 26, formed by provision of a notch 2'I in one side of the post.

The outer end of the post is at, as at 28, in a plane parallel to the bottom side 23 of the notch 27, and a cylindrical opening 33 extends through the head 26 perpendicular to the surfaces 23 and 29.

Carried by the two post heads 26, and bridging the space therebetween, is a blade-supporting structure, indicated in its entirety by the reference character 33, and comprising a backup bar 34 having a pair of studs 35 projecting perpendicularly from the upper face 36 thereof. Each stud 35 has a threaded terminal portion 3? of reduced diameter adapted to be received in a mating internally-threaded bore 38 of an adjusting nut 39 having a knurled nger piece 43, The threaded bore 38 has a guide portion 4I of larger diameter for close reception of the mating portion 42 of the stud 35. The adjusting nut 36 has a lower cylindrical portion 43` adapted to be rotatably received in the mating cylindrical opening 36 of the post head 26. It will be apparent that, as the adjusting nuts 39 are turned clockwise (assuming the stud terminal portions 31 are threaded right hand), the backup bar 34 will be drawn towards the outer end surfaces 23 of the post heads 25 to clamp between the latter surfaces and the upper surface 36 of the backup bar, a blade holder 44 carrying a blade ,45.

As best shown in Figs. 4 and 5, the blade holder 44 is in the form of a flat bar having parallel top and bottom faces 46 and 4l, respectively. The bottom face 4'! is provided with an elongated recess 48 opening through the front edge 49, the recess being of greater length than the blade r45 removably secured therein by suitable means, such as the pair of pins 50 having heads 5I. The blade 45, which is longitudinally slidable in the recess 48, has a pair of buttonhole-shaped slots adapted, when the blade is at one extremity of its sliding movement in the recess, to have their enlarged portions 62 vertically aligned with the headed pins 56, said enlarged portions 52 of the slots being of a size to pass the heads 5I of the pins for Vertical movement of the blade into and out of the recess. When the blade has been positioned in the recess with the pins extending through the slots enlarged portions 52, it may be slid longitudinally of the recess to the other extremity of its movement, when the pins will be disposed in the narrow portions 53 of the slots '4 which are narrower than the heads 5I of the pins, with the result that the heads overlie the blade and prevent its accidental removal from the l'eCeSS.

The holder 44 is provided with notches 55 in the terminal portions thereof adapted 'to closely embrace the studs 36 of the backup bar 34, when assembled therewith in the manner illustrated in Figs. 2 and 3.

Preferably, depth of the blade holder recess 46 is a few thousandths of an inch less than the thickness of the blade 45, with the result that when the blade, its holder and the backup bar are completely assembled, as in Fig. 2, the blade 45 is actually gripped by, and clamped between, the backup bar and the holder, the latter being clamped against the heads of the posts by the action of the adjusting nuts 33. The upper surface 36 of the backup bar 34 is provided with a pair of recesses 51 into which fit the heads 5I of the pins 56 when the entire blade-supporting structure 33 is assembled, (Fig. 3).

It is preferred that the blade holder upper surface 46 be beveled, as at 58, adjacent the front edge 43 from which the blade-cutting edge 59 projects, to provide ample clearance between the blade holder and the convex outer surface I4 of the dermatome body member I I, (Figs. 2 and 3).

Adjustment of the spacing of the blade-cutting edge 53 with respect to the body member convex surface ifi is obtained by insertion of shims of the desired thickness, between the blade holder and the post heads 26, (Figs. 3 and 8). Preferably, the shims have notches 6I adapted to embrace the studs 36, and finger' tabs 62 serving as handles.

It will be apparent that the structure described provides for use of a relatively thin and inexpensive blade, which can be used until dull, and then discarded and replaced. The rigid clamping action provided for the blade by the backup bar and the blade holder affords suitable support for a blade as thin and exible as must result from the use of material intended to be expendable.

fn Figs. 6 and 7 there is illustrated a modified construction differing from that just described in that the separate blade holder is omitted entirely, and the backup bar I6! is provided with a deep slot |62 rendering the top and bottom portions I 63 and I Q4, respectively, flexible relative to each other. lThe pair of studs I05 are secured in the bottom portion H34 and pass freely through openings |66 in the top portion ID3, with the result that tightening of the adjusting nuts 39 to draw the backup bar I ill toward the post heads 25 forces the top and bottom portions ID3 and i613 toward each other to clamp in the slot or recess M2 an expendable blade |08. The latter may be positioned in the slot or recess I 62, relative to the front edge of the slot, by a flange IElS, at the rear edge of the blade, received in a groove IIB formed in the bottom portion H34 of the backup bar IiI. In this construction, the blade I 63 is assembled in the bar by sliding it longitudinally into the recess |62 and groove IIO from an end of the bar.

While I have shown the invention in several forms, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. A blade holder for use with a dermatome of the type comprising a body member having a S convex surface, a pair of posts at opposite sides of the body member, blade-supporting structure carried by the posts at one end thereof, a blade supported by the blade-supporting structure, and means supporting the posts at their other ends from the body member for movement of the cutting edge of the blade parallel to, and at a predetermined distance from, the body member convex surface; said blade holder comprising a bar having a recess therein of a length greater than the length of the blade to be held thereby, and blade-securing means carried by said bar and so disposed with respect to said recess that a blade positioned in said recess at one extremity of the latter is freely removable therefrom and when disposed in said recess at the other extremity thereof is retained against free removal therefrom.

2. A blade holder as specified in claim 1, wherein recess.

JOHN D. REESE.

REFERENCES CITED The following references are of record inthe le of this patent:

UNITED STATES PATENTS Number Name Date 1,935,605 Altruda Nov. 21, 1933 2,288,709 Hood July 1, 1942 2,366,054 Reese Dec. 26, 1944

Images