US3664021A - Knife - Google Patents

Abstract

A power actuated knife with a single blade attached to a free end of a support, the other end of the support being attached to the handle. One end of the motor casing is attached to the handle through a vibration absorbing bearing and the motor at the other end has a rotatable oscillating connection to a bracket which engages the support at a location removed from its attachment to the handle whereby an oscillating sinusoidal motion is applied to the blade through the support to set the entire blade in motion.

Description

0 Muted States Patent [151 3,664,021 Sawyer May 23, 1972 KNIFE 3,359,637 12/1967 3416398 12/1968 2 l 1d [7 nventor Haro T Sawyer, Pacific Palisades, Calif 3,468,384 9/1969 [73] Assignee: Vernon D. Beeler, Los Angeles, Calif. a 3,316,428 4/1967 part interest [22] Filed: Oct 30, 1969 Primary Examiner-Theron E. Condon Assistant Examiner-J. C. Peters PP ,690 Attomey-Beehler & Arant 52 us. Cl ..30/272, 83/6475, 173/49 [57] ABSTRACT [51] Int. Cl ..B26b 7/00 A power actuated k if with a Single blade attached to a f [58] Field of Search ..30/272, 273, 169; 146/203, end ofa Support, the other end f the support being attached 146/204; 83/523 6 74/42; 173/49; 310/51 to the handle. One end of the motor casing is attached to the handle through a vibration absorbing bearing and the motor at [56] References cued the other end has a rotatable oscillating connection to a UNITED STATES PATENTS bracket which engages the support at a location removed from its attachment to the handle whereby an oscillating sinusoidal 2,320,784 6/1943 Livingston ..30/272 motion is applied to the blade through the Support to set the 2,958,355 11/1960 Young ....30/272 X entire blade in motion 2,984,005 5/1961 Evich ....30/272 3,052,981 9/1962 Landes ..30/272 9 Claims, 10 Drawing Figures full KNIFE As power actuated knives have become available on the market, virtually all have uniformly followed a design which incorporates two blades mounted side by side in engagement with each other, both of which are provided with edges which can aptly be described as saw-tooth edges, the blades being driven in such fashion that they move relative to each other so as to cut through the object with a sawing motion. A construction of the kind described requires an appreciable amount of motor power sufficient to move at least one of the blades, and often both of them, lengthwise for an appreciable distance at the end of which motion must be stopped and then reversed. Reciprocating motion of this kind consumes a considerable amount of power because at every reciprocation the moving blade must be brought to a stop and then started in the opposite direction. Appreciable mechanism is required in order to transmit motion from an electric motor to the moving blade and to adjust its speed relative to the normal speed of the motor so that at least one blade, and usually both blades, are moving at a desirable rate of speed. Obviously also, the blades must be confined one against the other so that their adjacent surfaces are in engagement since otherwise the cuttings and debris would accumulate between the blades and interfere with their proper motion. The problem is also present of confining the ends of both blades by means of which they are mounted in a position close together but still capable of being driven separately, and also requiring that they be mounted in such fashion that both of them can be removed after use for washing, drying and then replacement. The construction inherently needed for an apparatus of the kind described must be heavy because of the requirement for two blades stiff and rigid enough to be mounted and handled as described and also mounted in a handle big enough to accommodate a relatively powerful motor necessary to drive them.

Among the objects of the invention is to provide a new and improved power actuated tool which may be a knife blade or other comparable instrument whereby only a single blade is made use of mounted and operated in such fashion that rapid bending wave movement of the blade with a frequency comparable to the low sonic range is made use of in vastly increasing the ability of the blade to do the work it was designed for.

Another object is to provide by design a maximum and most efficient working tool with a minimum source of input energy.

Another object of the invention is to provide a new and improved power actuated tool which makes use of a single blade assembly mounted in cantilever fashion in a handle which also houses the motor, the assembly being such that a sinusoidal force generated in the motor is applied to the blade or a cantilever beam which supports it at a location removed from its resilient mounting, whereby to generate bending wave motions of vibration which are made use of to enable the blade to do its intended work.

Another object is to excite the blade tool member at bending wave motion speeds approaching 250 cycles per second as compared to 30 cycles of conventional electric knife motion speeds.

Another object of the invention is to perform physical work by exciting a bending wave force motion in the blade and thus causing a frequency deflection of the blade.

Still another object of the invention is to provide a new and improved power actuated knife which makes use of only a single cantilever mounted blade, the blade being removably attached to a cantilever-like mounting so that is can be removed for cleaning and replaced when needed, the motor power being applied to the mounting at a location within the handle housing so that the device is always ready for operation as soon as the blade is attached.

Still another object is to provide by design a system structure capable of functioning at or near its natural frequency so that maximum amplification of a power source can be achieved from a minimum input source,

Still another object of the invention is to provide a new and improved power actuated knife consisting of a single blade mounted in cantilever fashion in a handle which houses the source of motor power, the structure of the device as a whole being such that the moving parts act in resonance when power is applied to the blade.

Also included among the objects of the invention is to provide a new and improved power actuated single blade electrically operated knife which is extremely simple and inexpensive in its construction and assembly and which is especially effectiveas a cutting instrument.

With these and other objects in view, the invention consists in 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 illustratedin the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of the device showing the blade in place and ready for operation.

FIG. 2 is a longitudinal sectional view of the device.

FIG. 3 is a cross-sectional view of the blade on the line 3-3 of FIG. 2.

FIG. 4 is a cross-sectional view of the blade mounting on the line 44 of FIG. 2.

FIG. 5 os a fragmentary sectional view on the line 5-5 of FIG. 2.

FIG. 6 is a fragmentary sectional view on the line 6-6 of FIG. 2.

FIGS. 7 and 8 are schematic views of the blade showing different blade movements to which it is subjected.

FIGS. 9 and 10 are motion line diagrams.

In an embodiment of the invention chosen for the purpose of illustration there is shown a housing 10 which serves simultaneously as a handle and as a housing for the motor and its attachment to a tool, herein taking the form of a knife blade 11. Within the housing 10 is a pocket 12 in which is a rechargeable battery 13 and a chamber 14 within which is an electric motor 15, the motor being interconnected with the battery in a conventional manner, not shown. Leads 16 and 17 of the rechargeable battery 13 extend through a removable cap 18 so that the battery can be removed for replacement. Springs 19 and 19 serve to hold the battery snugly in position.

The electric motor is provided with a stub shaft 20 on a flange 20 by means of which the motor 15 is supported at one end only of the shaft on a partition 10' in the housing 10, the partition acting to separate the pocket 12 and the chamber 14. Mounting is accomplished by employment of a vibration damping unit 21 held in place by means of a setscrew 22. As shown in some detail in FIG. 6, a sleeve 23 and a shell 25 confine between them an isolation bearing mount 24 of shock absorbing material.

As will be noted, a bore 28 in the partition 10 accommodates the unit 21, the annular shell 25 being contained firmly therein so that there is no prospect of engagement with the stub shaft 20 and the sleeve 23.

At the other end of the motor is a rotating motor shaft 33 and an eccentric bearing assembly indicated generally by the reference character 30. The bearing assembly 30 consists of a bracket 31 within which is rotatably mounted a bearing race 32 commonly known as a self aligning ball bearing. Eccentrically mounted in the bearing race 32 is an eccentric bearing 34 which projects from the adjacent end of a stub shaft 36 confined in the bearing race 32, the motor shaft 33 being mounted in the eccentric bearing 34.

A permanently located mounting member is provided with a post 35 secured in a vibration damping unit 37 similar to the unit 21. The unit 37 in turn is secured within a closed pocket 38 by means of a set screw 39. The mounting member 35 may be compared with a tuning fork in that the mounting member 35 is free to move by reason of its inherent design. The mounting member 35 and the bearing assembly 30 are so connected to each other by means such as screws 31' and they are in constant engagement with each other as shown in FIG. 2. An outer end 40 of the mounting member 35 extends outwardly through a soft rubber seal 41 mounted in a removable plate 42 of the housing 10 whereby to effectively seal the interior of a recess 43 and also the chamber 14 from the exterior. The knife blade 11 has a butt end extension 44 which is removable attached to the outer end 40 of the mounting member 35 by an appropriate releasable connection 45.

In the chosen embodiment the connection 45 consists of a case 46 in which is a recess 47, wedge shaped in cross section, for reception of the butt end extension 44 which has also a wedge shape in cross section. A rotatable cam 48, manipulated by a handle 49 is adapted to force the wedge shaped parts together, thereby to releasably anchor the knife to the mounting member 35.

The knife blade 11, except for a small section near the butt end 44, may have a somewhat razor blade shaped cross sectional configuration, as shown in FIG. 3, there being a back edge 50 relatively stiff and heavy compared to a tapered blade edge 51. The height of the blade also varies from relatively narrow to relatively wide, as shown in FIGS. 7 and 8.

In operation, when the tool is to be put to use, the blade 11 is attached to the outer end 40 of the mounting member 35 and the motor 15 energized by means of a switch 53. As the motor shaft 33 is rotated by the motor the end of the motor shaft mounted in the bearing race 32 rotates so that the motor shaft 33, eccentrically mounted in the eccentric bearing 34 causes the bearing race to rotate relative to the eccentrically mounted motor shaft 33 thereby to impart sinusoidal motion to the bracket 31 at a rate depending upon the speed of rotation of the motor shaft 33. The sinusoidal motion set up in the bearing assembly bracket 31 is conveyed to the mounting member 35 and the blade 11 by direct contact of the bracket with the mounting member. The outer end 40, therefore, of the body of mounting member 35 is excited in sinusoidal motion, while its attached end is held relatively motionless by the unit 37. This sinusoidal motion is conveyed directly to the blade 1 I and the blade correspondingly set in motion.

The forms of the motion imparted to the blade 11 are illustrated by FIGS. 7 and 8 in that there is movement in different directions. For example, as illustrated by FIG. 7 the blade 11, mounted as a cantilever beam, is vibrated in a condition approaching resonance and moves horizontally in the direction illustrated by the wave line illustration 60. Actually, movement of the blade is ellipsoidal as indicated by the force motion end view 61. Three-dimensional ellipsoidal force patterns are released by the resonating cantilever beam in the form of the blade 11 in three planes. FIG. 8 shows vibration in the next higher mode, with motion indicated by the wave line 60 and end view 61 There is a sinusoidal driving force in the low sonic frequency range which by design is generated by the motor mass revolving at one end of that mass about its eccentric. That sinusoidal driving force is transmitted by means ofits supporting pedestal and bearing assembly to the mounting member, the whole acting as a tuning fork structure capable of being resonated with the cantilever beam structure embodied in the blade at a desired frequency and amplitude to do work commensurate with its application. When the blade is a knife blade sharp on one edge, that work will be cutting. Should the blade be a pallet knife, the work will be of some other kind. The device described performs work by means of resonance excitation at a desired frequency. By inherent design at a different frequency the resulting motion is exemplified by FIG. 7, where instead of a fundamental mode as illustrated in FIG. 9 action will be in a second mode of resonance and the force motion end view 61 will vary slightly from that illustrated by the reference character 62. Again, by inherent design at still a different frequency as illustrated in FIG. 8 a third mode of resonance may be induced in the blade 11 which will vary the force motion end view so that it will appear as represented by the reference character 61'.

To still further illustrate the motion of the blade 11 attention is directed to FIG. 10 wherein at a 90 phase angle is depicted for the first mode of resonance comparable to FIG. 9, the illustration of FIG. 10 being motion imparted to the blade in a direction toward and from its cutting edge, indicated at 63.

A typical operating example of the device is one wherein the sonic energy source is embodied in a small 1.5 volt or 3 .00 volt cylindrical motor of conventional construction and as illustrated by the motor 15. The mounting member 35 and outer end 40 which can effectively be described as a tuning fork resonating beam. Although a separate bracket 31 is shown, the bracket 31 and the mounting member 35 may be constructed of a single piece of material of proper consistency, held in position as described by the set screw 39. The connection between the mounting member 35 and the blade 11 is a rigid connection so that all motion imparted by the motor to the mounting member is conveyed directly to the blade 11.

The right hand end ofthe motor 15 has a stub shaft 20 and is confined as shown within the sleeve 23 forming a construction such that the motor casing is secured in the joint of FIG. 6 which may be described as a balljoint assembly permitting the motor shaft 33 to rotate radially relative to the longitudinal motor axis. At the other end of the motor 15 the shaft 33 is the output end for force generated by the motor mounted in the eccentric bearing assembly 34 which generates force is sinusoidal in nature, and the eccentric bearing assembly 34 being rigidly attached, mounting member 35 acting as a cantilever resonating beam assembly is motion driven into resonance by means of the motor 15 acting as a sinusoidal sonic energy source. The amplitude of the force is in proportion to the product of the motor mass and its eccentric throw at the bearing assembly 34. The resonating cantilever beam assembly is analogous to a plate beam or to a tuning fork, as previously suggested, and by proper design the resonating knife blade 11 may be designed to resonate freely at or near its own natural frequency at its first mode of resonance if desired. Further, by proper design in accordance with these principles, the knife may be so designed as to resonate in the second or, if preferred, in the third mode of frequency resonance which represents respective resonance frequencies of several times the fundamental driving force frequency, as previously made reference to in connection with FIGS. 7 and 8.

For example, should the fundamental frequency ofthe sonic energy source be cycles per second, by intrinsic design the first mode of resonance of the cantilever knife constructed as shown could be 80 cycles per second. Depending on the work to be done, the cantilever knife beam could be made to resonate at the second or third modes of any fundamental of the natural frequency of the knife beam.

The sonic energy source, namely the motor 15, is sound wave isolated at the right hand end as viewed in FIG. 2 where it is confined in the unit 21, thus providing a resilient radial support means which prevents longitudinal sound waves from entering the housing structure 10, serving in turn as the hantile.

The mounting member 35, serving as described as a tuning fork structure, is also isolated by means of its inherent design configuration. It should be understood that sound waves released by a resonating tuning fork travel in a direction toward the tuning fork prongs, by analogy, where their maximum amplitude and energy is released. It is clear therefore that the sound waves are not released or directed to the handle support structure in an assembly of the type described. The resonating cantilever knife beam and its supporting tuning fork structure comprise a complete system. The masses and springs of the system are designed to produce a resonant frequency of the complete system so that optimum conditions exist. The resonating cantilever beam and its supporting tuning fork mounting are in effect sounding bodies. When the cantilever beam is resonated at the point illustrated in FIG. 9, the beam will be resonating as a whole and, at the same time, there may be harmonics of the fundamental frequencies. The physical sinusoidal force resonating movement of the cantilever beam blade and its knife-like edge do in fact produce work when physically contacting another surface such as a surface to be cut. The device therefore does work when it cuts through the surface contacted, the work being performed by means of frequency motion in the low sonic range.

The physical resonating free movement of the cantilever knife beam is produced by longitudinal bending and sound waves which are initiated by the sound and energy source. When in resonance, the sinusoidal force motions are at a maximum, ellipsoidal in character, and are produced in each of the three planes of the cantilever beam.

The physical cutting forces at the knife edge of the resonating blade are derived from the longitudinal bending wave motions of the material in the resonating cantilever beam. The forces are three-dimensional in nature and ellipsoidal in structure. The physical cutting therefore takes place at the knife edge when contacting another surface by means of alternate three-dimensional force motion envelopes which are in planes parallel and perpendicular to the surface of the material being cut. it is the frequency and amplitude of the longitudinal sound and bending wave which sets up the resultant sound and bending wave through the resonating cantilever blade acting as a beam does in fact approach 1,100 feet per second in velocity. The foregoing explanation is believed amply warranted in view of the simplicity of the device, consisting at it does of a single blade, and the special effectiveness with which it performs. It will be appreciated from the explanation that the device is a composite unitary assembly the parts of which are so designed that they complement and enhance each other, to the end that a vibratory condition exists at or near the peak resonance curve when the device is in operation, and in this way enhances its effectiveness under circumstances where consumption of power is at a virtual minimum. As a consequence, the device is particularly light in weight in proportion to the work done.

lclaim:

l. A power actuated tool comprising a housing, a motor device having a resilient bearing mounting at one end only in said housing, a tool having a resilient bearing mount at one end mounted in said housing and a free end extending clear of said housing, and a sinusoidal force motion drive connection between said motor and said tool at a location on said tool intermediate said free end and said one end, said drive connection comprising a motor shaft on said motor, an eccentric member connected to and driven by said motor shaft and a connection between said eccentric member and said tool.

2. A power actuated tool as in claim 1 wherein the tool is a knife member and wherein said mounting comprises a resilient block with said knife member mounted as a cantilever beam and said sinusoidal force motion drive connection is in an edgewise direction relative to a sharp edge of said knife member.

3. A power actuated tool as in claim 1 wherein there is a closed chamber around said mounting for the tool and a yieldable seal around a portion of said tool extending outwardly from the housing.

4. A power actuated tool as in claim 3 wherein the tool has a mounting part located in said closed chamber and extending outwardly therefrom through said seal, and a working part having a removable connection to said mounting part at a location exterior relative to said housing.

5. A power actuated tool comprising a housing, a motor device mounted in said housing, a tool having one end mounted in said housing and a free end extending clear of said housing, and a sinusoidal force motion drive connection between said motor and said tool at a location on said tool in termediate said free end and said one end, said drive connection comprising a motor shaft on said motor, an eccentric member connected to and driven by said motor and a connec tion between said eccentric member and said tool, said motor having a single resilient mount at one end mounting said motor on the interior of said housing and wherein said force motion drive connection is at the other end of the motor.

6. A power actuated tool as in claim 5 including a rechargeable battery and battery chamber in said housing in axial alignment with said motor and electric connections between said battery and said motor.

. A power actuated tool as in claim 1 wherein said housing has its exterior in the form of a tool handle, and a switch on said housing connected to said motor.

8. A power actuated tool as in claim 1 wherein the force motion drive connection with said tool is a face to face pressure engagement and wherein said mounting for the tool is a resilient mounting biasing said tool toward said pressure engagement with said drive connection.

9. A power actuated tool as in claim 1 wherein said isolation bearing mountings are omnidirectional.

Claims (9)

1. A power actuated tool comprising a housing, a motor device having a resilient beAring mounting at one end only in said housing, a tool having a resilient bearing mount at one end mounted in said housing and a free end extending clear of said housing, and a sinusoidal force motion drive connection between said motor and said tool at a location on said tool intermediate said free end and said one end, said drive connection comprising a motor shaft on said motor, an eccentric member connected to and driven by said motor shaft and a connection between said eccentric member and said tool.

2. A power actuated tool as in claim 1 wherein the tool is a knife member and wherein said mounting comprises a resilient block with said knife member mounted as a cantilever beam and said sinusoidal force motion drive connection is in an edgewise direction relative to a sharp edge of said knife member.

3. A power actuated tool as in claim 1 wherein there is a closed chamber around said mounting for the tool and a yieldable seal around a portion of said tool extending outwardly from the housing.

4. A power actuated tool as in claim 3 wherein the tool has a mounting part located in said closed chamber and extending outwardly therefrom through said seal, and a working part having a removable connection to said mounting part at a location exterior relative to said housing.

5. A power actuated tool comprising a housing, a motor device mounted in said housing, a tool having one end mounted in said housing and a free end extending clear of said housing, and a sinusoidal force motion drive connection between said motor and said tool at a location on said tool intermediate said free end and said one end, said drive connection comprising a motor shaft on said motor, an eccentric member connected to and driven by said motor and a connection between said eccentric member and said tool, said motor having a single resilient mount at one end mounting said motor on the interior of said housing and wherein said force motion drive connection is at the other end of the motor.

6. A power actuated tool as in claim 5 including a rechargeable battery and battery chamber in said housing in axial alignment with said motor and electric connections between said battery and said motor.

7. A power actuated tool as in claim 1 wherein said housing has its exterior in the form of a tool handle, and a switch on said housing connected to said motor.

8. A power actuated tool as in claim 1 wherein the force motion drive connection with said tool is a face to face pressure engagement and wherein said mounting for the tool is a resilient mounting biasing said tool toward said pressure engagement with said drive connection.

9. A power actuated tool as in claim 1 wherein said isolation bearing mountings are omnidirectional.

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