U.S. patent number 3,832,776 [Application Number 05/308,952] was granted by the patent office on 1974-09-03 for electronically powered knife.
Invention is credited to Harold T. Sawyer.
United States Patent |
3,832,776 |
Sawyer |
September 3, 1974 |
ELECTRONICALLY POWERED KNIFE
Abstract
A single blade electronically powered knife has a cylindrical
case in which is located a solenoid having a centrally mounted
longitudinally oscillating rod. The inner end of the rod is
slidably retained in a bearing which has a resilient isolation
mounting within the case. On the outer end of the rod is secured a
mounting block which carries the knife blade and the mounting block
is isolated from the case by a resilient bearing. An electric power
source acting through an electronic circuit housed in the case
causes the solenoid to reciprocate the mounting block in a
longitudinal direction and impart sinusoidal elastic longitudinal
wave energy to the knife blade which translates into a cutting and
parting knife blade action.
Inventors: |
Sawyer; Harold T. (Pacific
Palisades, CA) |
Family
ID: |
23196047 |
Appl.
No.: |
05/308,952 |
Filed: |
November 24, 1972 |
Current U.S.
Class: |
30/272.1;
30/DIG.1; 310/30; 606/169 |
Current CPC
Class: |
A61B
17/3211 (20130101); Y10S 30/01 (20130101) |
Current International
Class: |
A61B
17/32 (20060101); B26b 007/00 () |
Field of
Search: |
;30/272,DIG.1,45
;310/28,29,30,34 ;128/303.14,305 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Peters; J. C.
Claims
Having described the invention, what is claimed as new in support
of Letters Patent is:
1. A drive assembly for a single blade electronically powered
knife, said drive assembly comprising: a case, longitudinally
oscillatable rod extending into the case, a blade mount anchored to
an outside end of the rod, a transversely and longitudinally acting
resilient isolation means secured between said blade mount, said
rod and the case, whereby to inhibit direct contact, and a
sinusoidally oscillating electric power source acting between the
case and the rod, which, when energized, imparts to the rod and to
the blade mount a sinusoidal elastic longitudinal wave motion
whereby to set up a sinusoidal elastic wave motion in the
blade.
2. A drive assembly as in claim 1 wherein there is a blade on the
blade mount, said blade having flat sides and a longitudinally
extending cutting edge intermediate said sides, and a spring mass
structure comprising the combination of blade, blade mount, and
rod, said spring mass structure having an oscillation rate at or
near resonant frequency and in phase with said power source.
3. A drive assembly as in claim 1 wherein the power source is a
solenoid having a central bore therethrough and the rod extends
through said central bore.
4. A drive assembly as in claim 3 wherein there is a transversely
mounted clapper of magnetic material attached to the rod at a
location adjacent to and spaced from one end of the solenoid
forming part of a magnetic path through the solenoid when the
solenoid is energized.
5. A drive assembly as in claim 4 wherein there is a means acting
between the rod and the blade mount to adjust the distance between
the clapper and the blade mount whereby to vary the amplitude of
the sinusoidal motion.
6. A drive assembly as in claim 1 wherein there is a bearing block
in the case having a bearing bore therethrough reciprocatably
receiving the end of the rod which is in the case, there being a
transversely and longitudinally acting resilient isolation mount
secured between the bearing and the case.
7. A drive assembly as in claim 6 wherein there is a lock nut in
engagement with the bearing block and in threaded engagement with
the the rod end which is in the case whereby to selectively set the
assembly at a different resonant frequency.
8. A drive assembly for a single blade electronically powered
knife, said drive assembly comprising: a case, a longitudinally
oscillatable rod extending into the case, a blade mount anchored to
an outside end of the rod, a resilient isolation bearing secured
between the blade mount and the case, and a sinusoidally
oscillating electric power source acting between the case and the
rod which when energized, imparts to the rod and to the blade mount
a sinusoidal elastic longitudinal wave motion whereby to set up a
sinusoidal elastic wave motion in the blade, the power source being
a solenoid having a central bore therethrough and the rod having a
position extending through said central bore, the power source
being a D.C. battery driven circuit comprising a coil for the
solenoid, and a transistor oscillator having leads connected
respectively to opposite ends of the coil and to the coil at an
intermediate location, whereby to periodically pulse said
solenoid.
9. A drive assembly as in claim 8 wherein the frequency is between
about 300 and 1,000 cycles per second.
10. A drive assembly as in claim 3 wherein the power source is an
A.C. push pull coil for the solenoid in communication with an A.C.
electric power source operating at a per second cycle rate of
between about 60 and 1,000 cycles per second.
11. A drive assembly as in claim 2 wherein there is a neck of
rectangular cross sectional shape forming an interconnection
between the blade mount and the blade, the long axis of said neck
lying in a direction transverse to the flat sides of the blade.
Description
SPECIFICATION
Electrically powered knives heretofore available have invariably
consisted of two blades mounted side by side in a handle with one
or both blades so manipulated that they reciprocate longitudinally
with respect to each other and produce a sawing action the nature
of which is similar to that of clippers. Such blades have the
disadvantage of always needing to be removed from the handle after
use in order to be cleaned separately and thereafter reinserted in
the handle when they are to be used again. Electric knives of this
description have been relatively large knives suited mainly for
carving meats and cutting bread. Although single blade knives have
been employed for cutting multiple layers of textiles in the
garment industry, such commercial type knives all need special
accessories and special handling in order to be useful.
Heretofore there has been little or no interest in making use of
electric or electronically powered knives for extremely fine and
precise cutting such as may be required, for example, in surgery.
Surgical knives currently in use, commonly known as scalpels, both
large and small, are hand manipulated single blades in one or
another of the great many forms, often involving detachable blades
on a special handle for specific applications. Such blades
generally have microscopic saw type teeth machined into the cutting
edge of the blade. Incisions and cutting are performed by
oscillating the blade in a motion which is in line with the center
line of the blade. For extremely precise work disadvantages attend
blades of this kind as for example there is invariably some
indentation of the skin or tissue during the cutting process which
is undesirable, such being particularly noticable in delicate
operations involving plastic surgery, eye operations, nerve
operations and such operations where delicate tissues are involved.
Since the scalpel is used in a slow back and forth motion the
tissue to be cut is minutely shreaded and this is undesirable.
Further still, the scalpel blade in itself has no parting action,
that is to say parting the tissues on opposite sides of the
incision, and this being necessary, it is done by hand manipulation
dependent on the skill of the surgeon.
It is therefore among the objects of the invention to provide a new
and improved single blade electrically powered knife which may, if
desired, be permanently mounted in the handle, and which is
essentially easy to clean or sterilize.
Another object of the invention is to provide a new and improved
electrically powered single blade knife which can be self contained
with the power supply compactly housed in a small handle and which
is capable of making an extremely precise incision virtually
without indentation of the material to be cut and which is gently
parted during the cutting operation by action of the knife blade
itself.
Still another object of the invention is to provide a new and
improved single blade electronically powered knife, capable of
being constructed in any one of a number of different sizes and
which is suitable for precise cutting operations such as those
encountered in surgery.
Still further among the objects of the invention is to provide a
new and improved single blade electronically powered knife which is
simple, positive and compact to the extent that a serviceable
cutting tool of high precision cutting ability can be made and
assembled without the use of complicated technique and which
requires virtually a negligible amount of service, the device
moreover being such that it can be powered either by a battery
contained in the knife handle or by an extension to a conventional
power supply.
With these and other objects in view, the invention consists of the
construction, arrangement, and combination of the various parts of
the device, whereby the objects contemplated are attained, as
hereinafter set forth, pointed out in the appended claims and
illustrated in the accompanying drawings.
FIG. 1 is a longitudinal sectional view of the electronically
powered assembly complete with blade.
FIG. 2 is a fragmentary plan view of the blade and the
mounting.
FIG. 3 is a cross-sectional view on the line 3--3 of FIG. 1.
FIG. 4 is a cross-sectional view on the line 4--4 of FIG. 1.
FIG. 5 is a cross-sectional view on the line 5--5 of FIG. 1.
FIG. 6 is a fragmentary longitudinal sectional view of a second
form of internal construction of the device.
FIG. 7 is a wiring diagram of a D.C. power source usable with the
device.
FIG. 8 is a wiring diagram for an A.C. power source.
FIG. 9 is a schematic view of a sinusoidal elastic longitudinal
wave motion within the solid material of the rod, the blade and
blade mounting.
FIG. 10 is a schematic view of ellipsoid force motions of the blade
when activated.
In an embodiment of the invention chosen for the purpose of
illustration there is shown a drive assembly indicated generally by
the reference character 10 at one end of which is a blade mount 11
which carries a blade 12. The blade 12 may be any one of a number
of different blade types depending upon the size and power of the
drive assembly, the blade illustrated being a scalpel. The action
imparted to the blade will, however, be the same whether it chances
to be a scalpel, a utility knife, a carving blade, or other
comparable single blade knife or chisel.
Located within a chamber 13 of a case 14 is a solenoid 15. The
solenoid is constructed with a cylindrical outer jacket 16 of
magnetic material and an inner sleeve 17 of magnetic material
spaced apart at one end by use of an annular spacer block 18 of
magnetic material and at the other end by use of a washer 19 of
non-magnetic material. The structure thus defined forms an annular
space 20 substantially occupied by a coil 21. Screws 22 extending
through the case into the solenoid hold it in position where it has
a snug sliding fit within the chamber 13.
The sleeve 17 provides a central bore 25 through which extends a
relatively long rod 26, the rod being of non-magnetic material as
for example, stainless steel. A clapper 27 which is of magnetic
material is anchored to the rod 26 by an appropriate weldment 28,
the clapper extending transversely over adjacent annular edges 29
and 30 respectively of the jacket 16 and sleeve 17.
To properly support an inside end 31 of the rod 26 use is made of
an annular inner section 32 of a tubular joint 33, therebeing a
bore 34 through the inner section which amply accommodates the rod
26. A bearing 35 of non-magnetic material is provided with a
central bore 36 forming a snug and freely sliding fit for the rod
26. An annular resilient spring isolation mount 37 is bonded to the
intersection 32 in a recess 38. The isolation mount 37 is likewise
bonded to the bearing 35 in a recess 39.
The opposite outer end 40 of the shaft 26 is provided with threads
41 which threadedly engage a recess 42 thereby to secure the blade
mount 11 in threaded engagement with the outer end of the rod. Once
in proper adjustment the set screw 43 anchors the parts together.
Separating the blade mount 11 from the case 14 is an annular
resilient spring isolation bearing 45. The isolation bearing is
bonded to the blade mount in a recess 46 and bonded to a plug 47 in
a recess 48. The plug, as shown, has a threaded engagement 49 in
the adjacent end of the case 14. In the chosen embodiment there is
at the base of the knife blade 12 a mass from which the blade
extends, the mass being connected to the blade mount 11 by a neck
51 of substantially rectangular cross-sectional configuration, the
long dimension being transverse to the flat dimension of the knife
blade and the short dimension being 90 degrees removed.
For varying the amplitude of endwise motion of the rod 26 the blade
mount 11 can be adjusted with respect to the outside end 40 of the
rod whereby to change the spacing of the clapper 27 from the
adjacent edges 29 and 30 of the solenoid.
The form of device of FIG. 6 shows another adjustment embodied in a
lock nut 55 engaging threads 56 at the inner end 31' of the rod 26.
By making use of the lock nut 55 adjustment of pressure on both the
isolation mount 37 and the spring isolation bearing 45 are made use
of in an opposing manner to alter the resonant frequency, depending
on the direction of adjustment.
When the drive assembly is to be self contained an annular housing
60 providing a chamber 61 may be attached to the adjacent end of
the case 10. The chamber 61 provides room for electric circuitry
and may be made large enough to contain an appropriate conventional
battery. A wire 62 from the solenoid 15 passes through a wire
channel 63 thence through a passage 64 into the chamber 61. A cap
65 closes the outside end of the chamber and when electrical energy
is to be supplied by an outside source the cap is provided with an
opening 66 through which wires from the power supply may pass.
A D.C. power circuit is shown in FIG. 7 supplied by a battery 70
from which a negative lead 71 is connected to a tap 72 at one end
of a coil 73 and a positive lead 74 is connected to a tap 75 at the
opposite end of the coil 73. A transistor oscillator 76 connects to
the positive lead 74 and from it a lead 77 connects to an
intermediate coil tap 78 to provide a trigger voltage, there being
a resistor 68 in the line. A switch 79 in the negative lead is made
use of to start and stop the operation. In the oscillator circuit
is a capacitor 69 connected across the coil 73 to form a tank
circuit.
When an A.C. power supply is to be made use of there is provided an
A.C. coil 80 accommodating a push-pull solenoid, the coil being
supplied by one lead 81 in which is a start/stop switch 82. A
second lead 83 supplies the opposite end of the coil 80.
When, for example, the D.C. circuit is used for operation of the
device, the switch 79 is activated causing a magnetic field to be
set up in the solenoid 15 through the outer jacket 16, the inner
jacket 17, the spacer block 18 and the clapper 27. This causes the
clapper to be attracted toward the solenoid imparting a
corresponding endwise motion to the rod 26 in a direction from left
to right as viewed in FIG. 1. When the excitation is momentarily
released, the attraction of the clapper 27 is likewise momentarily
released and the reversal of current in the coil effects an
opposite endwise motion in the rod 26 in a direction from right to
left as viewed in FIG. 1. These reversals of motion occur at a
specified frequency depending upon the design of the device. Acting
in the manner described a sinusoidal elastic longitudinal wave
energy pattern is generated represented by the nodal points 89 and
anti-nodal points 85 in FIG. 9. This wave pattern exists in the rod
26 and is conveyed by the rod to the blade mount 11 and mass 50 to
the blade 12 where a comparable wave pattern is set up. The result
of this wave pattern is the ellipsoid force motions schematically
shown in FIG. 10, there being an ellipsoid motion 86 in a direction
toward and away from the cutting edge of the blade, an ellipsoid
motion 87 in a direction transverse to the cutting edge of the
blade and an ellipsoid motion 88 diagonal with respect thereto. The
motion in the direction in alignment with the cutting edge of the
blade promotes the cutting force and the motion 87 in a direction
transverse to the cutting edge causes a parting motion in whatever
the material may be which is being cut.
When the electronically powered knife is to be made in a size
suited to surgery, where the knife is comparable to that of the
conventional scalpel, a low energy source employing a small D.C. 9
to 12 volt battery is found acceptable. The blade 12, the rod 26,
the blade mount 11 and mass 50, comprise a spring mass system which
is excited into an oscillating motion in line with the blade
structure by means of the solenoid and its associated circuitry.
The sinusoidal frequency of the oscillation represents the natural
frequency of the structure and its spring mass system which is
always in phase with the electronic sinusoidal frequency of the
system. The nodal natural frequency of the structure may be
conveniently chosen by design for a specific value over a range
from 300 to 1,000 cycles per second.
The back and forth, sinusoidal oscillation, frequency of the spring
mass longitudinal structure which is excited by the solenoid
oscillator in turn excites the free longitudinal rod and blade into
their own natural frequency which transmits throughout the
extremity and including the blade itself, thus to create an elastic
longitudinal sinusoidal wave motion within the metallic structure
material and which corresponds to the natural frequency.
A structure which is excited into its own natural frequency
releases force motion ellipsoid patterns in three planes as made
reference to in connection with FIG. 10, this being a significant
feature of the invention. For example, the sinusoidal longitudinal
wave energy which travels and is released to the blade causes the
blade to release ellipsoid wave energy motions within its own
structure and of minute motional extent in the three planes
indicated.
The oscillating motion of the blade causes high speed delicate
cutting without causing indentation of the tissue or material to be
cut, the transverse ellipsoid force motion of the blade creating
its own minute parting action during incision.
Depending on the ultimate use to be made of the device an
acceptable operating frequency range can be set up between 60 and
1,000 cycles per second. A typical D.C. circuit can be made to
operate satisfactorily on either a 6 volt or 12 volt D.C. battery
applied across the D.C. coil.
In the setup described for D.C. operation, the feedback voltage of
the coil 73 causes the cricuit to go into oscillation at a
frequency determined by the resonant frequency of the rod, blade
mount and blade assembly which is in effect a free-free spring mass
system. It is therefore a self excited oscillator. The oscillator
circuit will automatically follow one of the nodes of natural
frequency of the rod and blade assembly and its inherent spring
mass structure by means of its own feedback nature.
The design of the coil is matched specifically to the
characteristics of the oscillator circuit and to the resonant,
frequency structure. The resonant frequency of the electrical
circuit therefore is in resonance and in phase with the natural
frequency of the mechanical structure. The total or combined
electromechanical system therefore flows into electromechanical
resonance thus only utilizing a minimum amount of power which is a
significant aspect of the invention and work to be accomplished.
The frequency generated is therefore the natural frequency of the
circuit and is the frequency at which it will oscillate and in
phase with the natural and resonant frequency of the rod and blade
assembly which comprises the spring mass structure.
When an A.C. coil like the A.C. coil 80 is made use of on a 110
volt 60 cycle power supply the resonant rod and blade assembly is
designed for a fixed frequency of 60 cycles per second. The
resonant rod and blade assembly in such a design is designed for
one of its modes of natural frequency which is excited by the
fundamental frequency of 60 cycles per second. A desirable
structure frequency in this case has been found to be within one of
the modes of natural frequency by design, which may be chosen
within an acceptable range of from 120 to 300 cycles per
second.
While the invention has herein been shown and described in what is
conceived to be a practical and effective embodiment, it is
recognized that departures may be made therefrom within the scope
of the invention.
* * * * *