U.S. patent number 3,583,403 [Application Number 04/649,254] was granted by the patent office on 1971-06-08 for dermatome.
This patent grant is currently assigned to Austenal Europa, Inc.. Invention is credited to Arnold Keller, Fritz Georg Pohl.
United States Patent |
3,583,403 |
Pohl , et al. |
June 8, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
DERMATOME
Abstract
The invention relates to a dermatome as used for surgical
purposes to sever a strip of skin from a patient's body prior to
transplantation. The invention lies in an adjustment device having
an adjustment screw received in a threaded bore of a crossmember
connecting the sidewalls of the cutting head of the dermatome. The
lower extremity of the adjustment screw loosely engages a recess
formed in a pivotally mounted gauge bar disposed forwardly of the
cutting blade. This gauge bar with its recess is constantly urged b
spring action, assisted by the contact pressure during operation of
the dermatome, against the lower extremity of the adjustment screw.
The gauge bar is drivingly connected via a leverage transmission
with an indicator journaled on the cutting head and cooperating
with a stationary scale. In a preferred embodiment the cutting
blade is loosely placed in the cutting blade holder and prevented
against shifting by positioning means. The cutting blade is
resiliently clamped against the cutting blade holder by a pivotal
cover engaging the cutting blade near its cutting edge. This cover
does not move during the cutting operation of the dermatome and
forms a guiding ramp for the severed strip of skin.
Inventors: |
Pohl; Fritz Georg
(Kiel-Dietrichsdorf, DT), Keller; Arnold
(Kiel-Dietrichsdorf, DT) |
Assignee: |
Austenal Europa, Inc.
(Kiel-Dietrichsdorf, DT)
|
Family
ID: |
24604046 |
Appl.
No.: |
04/649,254 |
Filed: |
June 27, 1967 |
Current U.S.
Class: |
606/132 |
Current CPC
Class: |
A61B
17/322 (20130101) |
Current International
Class: |
A61B
17/322 (20060101); A61b 017/322 () |
Field of
Search: |
;128/305,305.5,303.14
;145/10,15,20 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Pinkham; Richard C.
Assistant Examiner: Apley; Richard J.
Claims
What we claim is:
1. A dermatome comprising in combination, a cutting head, a sliding
surface defined on said head adapted to engage and slide over the
skin during the cutting procedure, said surface intersecting a
sharp edge extending toward and transversely to the direction of
sliding, a cutting blade supported in said cutting head and
arranged obliquely relative to said sliding surface engaging said
sharp edge and including a cutting edge disposed adjacent said
sharp edge of said sliding surface, an elongated gauge bar
pivotally mounted on said cutting head forwardly of said sharp edge
and said cutting edge with respect to the direction of operative
movement, a flat, planar, gauge edge defined on said gauge bar
extending in spaced parallel relation to said sharp and cutting
edges defining a guide surface, said gauge bar being pivotally
supported on said head about an axis parallel to said gauge edge
and cutting edge, adjustment means mounted on said head for
pivoting said gauge bar about saId axis to vary the relationship of
said gauge edge to said cutting edge, indicating means mounted on
said head indicating the angular relationship of said gauge bar to
its pivot axis to indicate the relationship of said gauge edge to
said cutting edge and the depth of cut being taken, said indicating
means including an indicator drive pin affixed to said gauge bar
offset with respect to said gauge bar pivot axis, an indicator
pivotally mounted upon said cutting head, indicia defined on said
cutting head adjacent said indicator, and connecting means
interconnecting said indicator drive pin and said indicator wherein
pivotal movement of said gauge bar about said axis is indicated by
said indicator.
2. A dermatome as in claim 1 wherein said adjustment means includes
an adjustment screw threaded upon said cutting head, said screw
having a lower end disposed toward said gauge bar, a recess defined
in said gauge bar offset with respect to said pivot axis receiving
said screw lower end, and biasing means pivoting said gauge bar in
a direction maintaining said screw lower end in engagement with
said recess wherein adjustment of said screw adjusts the angular
relationship of said gauge bar to its axis.
3. A dermatome as in claim 1 wherein said gauge bar includes a
forwardly disposed rounded, chamfered edge extending parallel to
said gauge edge, and said pivot axis is disposed adjacent said
rounded, chamfered edge and is defined by axle journals extending
through sidewalls defined upon said cutting head and received
within bores defined in ends formed on said gauge bar.
4. A dermatome as in claim 1 wherein said cutting head includes a
central forward region disposed forwardly of said gauge bar and
cutting edge with respect to the direction of operative movement, a
pair of cutting edge protective shoes slidably mounted upon said
cutting head, a shoe being located at each lateral side of said
head with respect to said central region and forwardly of said
cutting edge preventing engagement of said cutting edge with the
skin being cut at the location of said protective shoes and
adjusting means for simultaneously moving said protective shoes
toward and away from said central region.
5. In a dermatome as in claim 1, means mounted upon said cutter
head for laterally reciprocating said cutting blade, a cover
mounted upon said cutting head disposed adjacent and above said
cutting edge, and rearwardly therefrom with respect to the
direction of operative movement for receiving the skin being cut,
said means supporting said cutting blade supporting said cover in a
stationary manner with respect to said cutting head.
6. A dermatome comprising, in combination, a cutting head, a
sliding surface defined on said head adapted to engage and slide
over the skin during the cutting procedure, said surface
intersection a sharp edge extending toward and transversly to the
direction of sliding, a cutting blade supported in said cutting
head and arranged obliquely relative to said sliding surface
engaging said sharp edge and including a cutting edge disposed
adjacent said sharp edge of said sliding surface, an elongated
gauge bar pivotally mounted on said cutting head forwardly of said
sharp edge and said cutting edge with respect to the direction of
operative movement, the rear and bottom planar surfaces of said
gauge bar converging in a sharp gauge edge extending in spaced
parallel relation to said sharp and cutting edges defining a guide
surface, said guage bar being pivotally supported on said head
about an axis parallel to said gauge edge and cutting edge,
adjustment means mounted on said head for pivoting said gauge bar
about said axis to vary the relationship of said gauge edge to said
cutting edge, indicating means mounted on said head indicating the
angular relationship of said gauge bar to its pivot axis to
indicate the relationship of said gauge edge to said cutting edge
and the depth of cut being taken, said indicating means including
an indicator drive pin affixed to said gauge bar offset with
respect to said gauge bar pivot axis, an indicator pivotally
mounted upon said cutting head, indicia defined on said cutting
head adjacent said indicator, and connecting means interconnecting
said indicator drive pin and said indicator wherein pivotal
movement of said gauge bar about said axis is indicated by said
indicator.
Description
DESCRIPTION OF THE PRIOR ART
Dermatomes of this type are known which comprise: a cutting head
the underside of which forming a sliding surface sliding along over
the skin during the cutting procedure, this sliding surface being
defined forwardly by a sharp edge extending transversely to the
direction of sliding; a cutting blade supported in the cutting head
and arranged obliquely relative to the sliding surface, abutting
the sharp edge, and projecting with its cutting edge into the
cutting surface defined by the sliding surface; a gauge bar
arranged within the cutting head forwardly of the sharp edge with
respect to the direction of sliding, and including a gauge edge
extending in spaced parallel relation to the sharp edge, and
defining a guide surface extending in a forward direction
therefrom, said gauge bar being pivotally supported about an axis
extending in parallel relation to said gauge edge; adjustment means
for pivoting said gauge bar arranged in a crossmember connecting
the sidewalls of the cutting head, and including an adjustment
screw engaging said gauge bar in spaced relation from said pivot
axis; and indicating means for the cutting depth defined by the
normal distance between said gauge edge and said cutting
surface.
This known dermatome has a gauge bar with a curved sliding surface,
the lowermost point of which being disposed approximately at the
cutting edged of the cutting blade. When a strip of skin is severed
the rounded sliding surface of the gauge bar causes bulging of the
skin directly in front of the cutting edge of the cutting blade
whereby the exact maintenance of the cutting depth is impaired,
which may be prevented if a gauge bar with a planar sliding surface
is used. But the essential drawback of this known dermatome must be
seen in the adjustment device for the gauge bar, and also in the
indicating device of the cutting depth. A micrometer screw serves
as adjustment device mounted rotatably but axially nonshiftably in
the crossmember connecting the sidewalls of the cutting head. The
micrometer screw is screwed into a threaded bore of the gauge bar.
Since the micrometer screw can only be rotated, but is otherwise
fixed in its position relative to the crossmember, and since, upon
adjustment of the cutting depth, the gauge bar is caused to pivot
about its pivot axis, the axis of the threaded bore and the axis of
the screw can only coincide in one position, but must include an
obtuse angle in any other position. Therefore, it is necessary, if
in this manner an adjustment of the cutting depth is to be obtained
at all, to provide so much clearance either in the bearing support
of the micrometer screw, or between the interior and exterior
thread that a precise adjustment is impossible.
Another drawback is to be seen in the indicating device for the
cutting depth. The end face of the head of the micrometer screw is
provided with an angular graduation which, corresponding to the
pitch of the thread, represents from scale mark to scale mark a
defined adjustment measure of the cutting depth. If one starts out
from the fact that a dermatome should have an adjustment range
between 0 and 2 mm. then the pitch of the micrometer screw should
be 2 mm., if the total adjustment range is to be covered with one
revolution of the micrometer screw. A screw with such a high pitch
cannot be considered as micrometer screw. However, if a lesser
pitch of the thread is provided correspondingly more revolutions of
the screw become necessary, if the cutting depth is to be adjusted
over the total range. But in this case the operator of the
apparatus does not know whether the screw had been adjusted already
prior to its use out of the zero position so that this, being of
the opinion that the micrometer screw had been in a zero position
but in fact was not, might lead to serious mistakes. But even if
this known dermatome provides an adjustment range and therefore a
pitch of 2 mm., which would require a multiple thread, so as to
avoid the aforementioned errors then this high pitch in connection
with the first-mentioned drawback regarding the necessary clearance
would cause a still greater inaccuracy regarding the fine
adjustment.
In this known dermatome, from which the invention starts out, the
cutting blade is screwed by hexagon head screws on the blade
holder, the heads of which project beyond the upper surface of the
holder. On the one hand the replacement of the cutting blade is in
this construction cumbersome and not possible without using a
spanner.
In addition, the upper surface of the blade holder forms a guide
path for the severed strip of skin. Since the cutting knife in
severing strips of skin reciprocates and, besides this, the
mounting screws of the blade project into the guide path of the
severed strip of skin, it is necessary, for avoiding damages of the
strip of skin, that the latter is seized by a second person
immediately upon severance and kept clear of the upper blade
surface.
In another known dermatome one has chosen a construction of the
adjustment device for the gauge bar inverted to that one of the
above-described dermatome. In this case the adjustment screw is
screwed into the crossmember connecting the sidewalls of the
cutting head. The end of the adjustment screw is formed as a tenon
provided with a circumferential groove. The tenon engages a bore of
the gauge bar and is secured thereto rotatably but axially
nonshiftably by a pin provided in the gauge bar and extending
tangentially through the circumferential groove. Also in this case
the same drawback may be observed as in case of the prior-described
dermatome, because, if the gauge bar is to be adjusted by pivoting
motion, there must be ample clearance between the pin and the
circumferential groove of the tenon so that, in view of such a
loose connection, an exactly adjustable cutting depth and
maintenance of the same cannot be expected. An indicating device
for the cutting depth is not provided so that the cutting depth
must be guessed, which should be avoided under all
circumstances.
Further dermatomes are known in which the adjustment movement of
the gauge bar is not pivotal but a linear movement in straight line
guide. This is advantageous in that the guide surface of the gauge
bar is always disposed in approximately parallel relation to the
cutting plane, and in that the guidance and holding of the gauge
bar is unobjectionable and free of play, however is afflicted with
the disadvantage of substantially higher manufacturing costs, and
the more difficult disassembly of the apparatus for the purpose of
cleaning and sterilizing. In this it is known to provide a
stationary adjustment scale at one of the sidewalls of the cutting
head for predetermining the cutting depth. An indicator is moving
above the scale simultaneously serving as actuator for the
adjustment device. The indicator is rigidly mounted on an eccentric
shaft, by rotation of which the gauge bar may be shifted upwardly
or downwardly. This type of adjustment device is expensive in
manufacture, because it requires precise machining of the cam
surfaces cooperating with the eccentrics. In addition the
eccentrics require accurate setting which is done by the
manufacturer. A further drawback is to be seen in the fact that
equal angular rotations of the eccentric shaft do not result in
equal movements of the gauge bar, so that the spacings of the scale
marks become uneven, if they are to indicate equal strokes of the
gauge bar, and this again complicates the production.
This invention aims to improve the initially described dermatome in
such a manner that, in spite of a simple construction, allowing a
quick and easy disassembly for cleaning and sterilization, an
essentially more precise adjustment and maintenance of the cutting
depth is achieved, than is attainable in the known apparatus. In
addition an indicating device for the cutting depth is to be
provided having a range from 0 to 2 mm., in which errors of the
adjustment are avoided, and in which equal movements of the gauge
bar are transmitted into equal movements of the indicator, so that
the indicating scale has marks evenly spaced. Further, in a
preferred embodiment a novel mounting of the cutting blade is to be
provided which is very simple in construction, allows an easy and
quick replacement of the cutting blade, without requiring any
tools, and which, at the same time, provides a smooth not movable
guide and sliding surface for the severed strip of skin extending
over the entire width of the apparatus, thereby requiring only one
person for its operation.
SUMMARY OF THE INVENTION
According to the invention the problem is solved in that the
adjustment screw of the adjustment means is screwed, in a manner
known per se, into a threaded bore of the crossmember of the
cutting head, and that the lower end of the adjustment screw
loosely engages a recess formed in the gauge bar, which latter is
urged in constant abutment against the adjustment screw by the
contacting pressure of the apparatus, assisted by spring means, and
that the indicating means for the cutting depths comprise a
stationary scale, known per se, and an indicator journaled on the
cutting head and drivingly connected by a leverage transmission
with the gauge bar.
A very suitable embodiment which prevents bulging of the skin
immediately in front of the cutting edge of the blade and which
assures that the skin is severed accurately with an even thickness
is obtained when the gauge bar has a planar guide surface defined
at the side opposite of the adjustment edge by a rounded, chamfered
edge extending in parallel relation to the adjustment edge, and
when the pivot axis is arranged adjacent the rounded, chamfered
edge and is formed by axle journals extending through the sidewalls
of the cutting head and engaging into bores provided in the gauge
bar. In this an advantageous effect is achieved when at a maximum
cutting depth, the guide surface of the gauge bar is disposed
substantially in parallel relation to the sliding surface of the
cutting head and includes an obtuse angle with the sliding surface
at smaller cutting depths.
A preferred construction of the indicating means provides that the
indicator of the indicating means and the scale are arranged, in a
manner known per se, at one of the sidewalls of the cutting head,
and that the indicator is rotatably supported at the sidewall on an
axis extending in parallel spaced relation to the pivot axis of the
gauge bar adjacent its adjustment edge, and further that an
indicator drive pin extending in spaced relation to the indicator
axis and secured to the gauge bar extends through an aperture of
the sidewall and projects into an elongated hole of the indicator,
and that the length of the indicator and the spacings of the axes
between the pivot axis of the gauge bar and the indicator drive
shaft, as well as between the latter and the indicator axis are
chosen in accordance with a defined transmission ratio.
In order to facilitate the width adjustment of the skin to be
severed the invention provides that the cutting head is provided in
a manner known per se, with adjustment sliding shoes for adjusting
the width of the cut.
An especially suitable embodiment of the invention which allows
operation of the dermatome by a single person and yet avoids with
certainty that the severed skin is damaged by the oscillating
cutting blade is characterized in that the cutting blade is loosely
insertable into the cutting blade holder and is held in its
position by positioning means, and that a cover is provided
arranged above the cutting blade holder and is pivotally supported
about an axis extending in parallel, rearwardly spaced relation to
the cutting edge of the blade, the forward edge of said cover
engaging resiliently the cutting blade arranged therebelow, and
that the upper surface of the cover forms a stationary guide path
for the severed strip of skin. In this embodiment the sidewalls of
the cutting head are provided with bosses having threaded bores
formed therein into which screws extending through the cover are
threaded, a compression spring being arranged between each head of
the screws and the cover, whereby the cutting blade is resiliently
urged against the oscillating cutting blade holder.
The positioning means for the cutting blade of this embodiment may
comprise two spacedly arranged projections provided on the cutting
blade holder and engaging corresponding apertures provided in the
cutting blade.
Suitable embodiments of the subject matter of the invention shall
now be explained by way of example in connection with the attached
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows a front elevational view of the cutting head of a
dermatome in accordance with the invention;
FIG. 2 shows a top view of the cutting head according to FIG.
1;
FIG. 3 shows a cross-sectional view along the line 3-3 of FIG.
2;
FIG. 4 shows a side view of the dermatome cutting head shown in
FIG. 1 to 3;
FIG. 5 shows in a diagrammatic manner the important members of the
cutting head according to the invention, substantially in
correspondence with FIG. 3, but in an enlarged scale;
FIG. 6 shows a longitudinally sectional elevation of a dermatome in
accordance with the invention, however, in a modified and improved,
preferred embodiment;
FIG. 7 shows a partial longitudinal sectional view in an enlarged
scale of the dermatome illustrated in FIG. 6; and
FIG. 8 shows a top view of the apparatus according to FIGS. 6 and 7
with the cover removed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawings FIGS. 1 to 5 the illustrated cutting head comprises
a baseplate 28, the underside of which forming a sliding surface 2.
The forward end of this baseplate forms a knife edge 3 on which a
cutting blade 4 rests, which is supported in the cutting head and
projects with its cutting edge 5 into the cutting plane defined by
the sliding surface. The mounting means of the cutting blade 4 are
not shown in the drawings. Sidewalls 13 and 14 extend upwardly from
the lateral edges of the baseplate 28, and project forwardly beyond
the knife edge 3, the upper edges of the sidewalls 13 and 14 are
connected by a crossmember 20. Rearwardly, the sidewalls 13 and 14
are connected by a crossmember 20. Rearwardly, the sidewalls 13 and
14 extend to holding means for the cutting head (not shown). Below
the crossmember 20 a substantially square gauge bar 6 is pivotally
supported by axle journals extending through the sidewalls 13 and
14 and projecting inwardly into bores of the gauge bar 6. The axle
journals may, for example, form parts of screws screwed through
threaded bores of the sidewalls 13 and 14. The gauge bar 6 is
disposed in sliding direction forwardly of the knife edge 3 and the
cutting edge 5, and includes an adjustment edge 7 extending
substantially in parallel, spaced relation to the knife edge 3 and
the cutting edge 5 of the blade 4, which adjustment edge 7 may be
lifted, or lowered respectively, relative to the cutting edge 5 of
the blade 4 by pivoting the gauge bar 6 about the axis 11. The
underside of the gauge bar 6, extending forwardly from the
adjustment edge 7, forms a guide surface smoothening the skin
bulging in front of the dermatome during the cutting operation, and
thereby feeding the skin in a proper manner to be cut towards the
cutting edge 5 of the blade 4. The normal distance between the
adjustment edge and the cutting plane formed by the sliding surface
2 defines the cutting depth. The cutting width is determined by two
sliding shoes 27 extending on either side over the lateral edges of
the knife edge and the cutting edge 5 of the blade. The sliding
shoes 27 are mounted on two supports 29. Each support 29 includes
an upper and a lower bore through which guide rods 30 and 31
extend, and a threaded bore is disposed between the guide bores of
each support 29 and receives a threaded spindle common for both
supports 29. This threaded spindle is over each half of its length
provided with right- and left-hand threads, whereby, upon rotation
of the threaded spindle by means of the knurled knob 33, the two
supports 29 and thus the two sliding shoes 27 are moved
simultaneously in opposite directions. The guide rods 30 and 31, as
well as the threaded spindle 32 are supported in the forward ends
of the side walls 13 and 14.
The adjustment of the gauge bar 6 is achieved by means of an
adjustment device 9. This adjustment device 9 comprises as an
essential member an adjustment screw disposed in a threaded bore 17
of the screw member 20, and provided at its upper end with a
knurled knob 34. The adjustment member proper is formed by a
downward extension 12 of the adjustment screw. The lower end of the
adjustment member 12 seats on an abutment point 16 within a recess
21 of the gauge bar 6. This abutment point 16 is, with respect to
the pivot axis 11 of the gauge bar 6, rearwardly spaced. The gauge
bar 6 is urged against the adjustment member 12 of the adjustment
screw by two tension springs 19. These springs 19 are secured with
their one ends to the gauge bar 6 at points rearwardly spaced with
respect to the pivot axis 11, in the same manner as the abutment
point 16, and with their other ends to fixed points of the cutting
head. In this zone an indicator drive pin 26 extends cutting
process one of the side surfaces of the gauge bar 6 and projects
through an aperture in one of the sidewalls 13 beyond its other
surface, where it drivingly engages into an aperture of the
indicator 22. The indicator 22 is rotatably journaled in the
sidewall 13 about an axis 23, for example formed by a threaded pin,
and moves over a scale 25 arranged on this sidewall. Depending on
the chosen distance between the indicator drive pin 26 and the
indicator axis a more or less greater transmission ratio, and thus
a more or less spaced scale graduation is obtained. As particularly
evident from FIG. 3, the sliding surface 2 and the guide surface 8
of the guage bar include an obtuse angle when the cutting depth is
set to zero, i.e. a disappearingly normal distance between the
adjustment edge of the gauge bar 6 and the cutting edge 5 of the
blade 4. However, at a maximum cutting depth the guide surface 8
and the sliding surface 2 extend substantially in parallel
relation. By means of this change of the angle of approach between
the sliding surface and the guide surface the bulging skin caused
during the cutting process in front of the cutting head is pressed
together in such a manner that at any cutting depth a smooth,
continuous cut is achieved.
The mounting means of the cutting blade 4 (in FIG. 1 to 5 not
illustrated) is attached in a known manner, to drive means
laterally reciprocating the cutting blade 4.
As may be seen from FIGS. 6 to 8 a preferred improved embodiment of
the dermatome according to the invention consists of a cutting head
100 to which a handle 101 with a built-in motor (not shown) is
secured. On the freely projecting end of the motor shaft 102 and
eccentric roll is journaled engaging into a fork 104 of a cutting
blade holder 105, to be described in detail yet, so as to drive the
same in a laterally reciprocating manner.
The cutting head 100 is construed in form of a shovel, comprising a
baseplate 106 the underside of which forming a sliding surface 107
with which the dermatome is slidingly guided across the skin to be
severed. The forward end of the baseplate is chamfered under an
acute angle toward the sliding surface 107, thereby forming a
backing surface 108 on which the forward end of the cutting blade
holder 105 rests which is also chamfered so as to form a
continuation of the sliding surface 107 of the base plate 106 of
the cutting head 100.
The cutting head further includes side walls 109 and a rear wall
carrying the handle 110. On an axis 111 extending transversely to
the sidewalls 109 the cutting blade holder 105 is slidingly and
pivotally supported. Adjacent the forward end the cutting blade
holder is, according to the invention, provided with two upwardly
projecting pins 112 spaced relative to each other, which pins serve
to receive and position the cutting blade 114 provided with
corresponding apertures, similar to a razor blade of a shaving
apparatus, wherein the cutting edge of the blade 114 projects a
small distance beyond the forward edge 115 of the cutting blade
holder 105.
According to the invention a cover 116 is provided above the
cutting blade holder 15 extending between the sidewalls 109 of the
cutting head 100 over its entire width. The cover 116 is secured to
the cutting head 100 by two screws 117 with knurled heads one
arranged on either side. These screws extend through corresponding
holes 118 in the cover 116 and are screwed into threaded bores 119
of eyes 120 provided on the sidewalls 109. Compression springs 122
are arranged between the knurled heads 121 of the screw 117 and the
upper surface of the cover 116 resiliently urging the cover 116
downwardly. The cover extends slantedly downwardly towards the
cutting blade and engages with its forward end resiliently the
cutting blade a small distance rearwardly spaced from the cutting
edge of the cutting blade 114, which in this way is clamped between
the reciprocatingly driven cutting blade holder 105 and the
stationary cover 116.
Thus on the one hand the cover serves as a clamping element for
holding the cutting blade 114, but on the other hand it also forms
a stationary guiding ramp for the strip of skin severed by the
cutting blade, past which the same may slide unobstructedly, so
that damages of the trip of skin, the thickness of which may vary
between 0.2 and 2 mm., are surely avoided. Further, it is not
necessary anymore that, as was common practice, a second person has
to seize the strip of skin immediately upon severance by the
cutting blade and to lift it free of the reciprocating cutting
blade in order to avoid damages of the skin.
An adjustment device 123 for adjusting the cutting depth is
arranged in front of the cutting blade 114, and includes a gauge
bar 125 supported to pivot about an axis 124 extending in parallel
relation to the cutting edge of the cutting blade. This gauge bar
125 is pulled into abutting engagement against the face of an
adjustment screw 127 by tension springs 126. The adjustment screw
127 extends through a threaded bore 128 provided in a crossmember
129 connecting the two sidewalls 109 of the cutting head. The gauge
bar 125 is drivingly connecting via a lever arrangement with an
indicator moving over a scale provided on one of the sidewalls
109.
The adjustment device 123, and the indicating device for the
cutting depth cooperating therewith, have been described in detail
with regard to the embodiment shown in FIGS. 1 to 5.
It is to be understood that modifications within the limits of the
attached claims are possible without departing from the scope of
the invention. Thus, instead of the two positioning pins 112 also
an elongated ledge may be provided engaging into a corresponding
slot of the cutting blade. Also, the arrangement could be inverted
by providing the positioning means on the cutting blade and the
receiving aperture, or apertures respectively, in the cutting blade
holder. Further, it is possible to construct the mounting means of
the cover 116 in a different way, for example by pivotally hooking
the cover to the cutting head and urging it downwardly by lead
springs, adapted to be moved out of the way.
* * * * *