US3530577A - Vibrating tool construction - Google Patents

Description

Sept. 29, 1970 B. P. FRANKLIN ETAL 3,530,577

VIBRATING TOOL CONSTRUCTIQN Filed July 25, 1967 2 Sheets-Sheet 1 ml' r FIG. l2

FIG.

INVENTORS BURTON P. FRANKLIN PAUL w. BLESS 7 ATTORNEY I L I Sept. 29, 1970 B. P. FRANKLIN' 3,530,577

- VIBRATING TOOL CONSTRUCTION Filed July 25, 1967 2 Sheets-Sheet 2 I77 I25 I33 '6' INVENTOR$ BURTONP. FRANKLIN PAUL W. BLESS ATTORNEY United States Patent 3,530,577 VIBRATING TOOL CONSTRUCTION Burton P. Franklin, Danville, Va., and Paul W. Bless, Durham, N.C., assignors, by mesne assignments, to The Black and Decker Manufacturing Company, Towson, Md., a corporation of Maryland Filed July 25, 1967, Ser. No. 655,852 Int. Cl. B27g 17/04; E02d 7/18 U.S. Cl. 30-169 Claims ABSTRACT OF THE DISCLOSURE SUMMARY OF THE INVENTION The present invention relates to a portable, motor powered vibrating tool construction which includes a frame having a remotely disposed, interconnected drive motor and vibratory source supported thereon. An implement is supported upon the frame and is disposed relative to the vibratory source so as to be controllably vibrated when the motor is energized. A handle is secured to the frame remote from the vibratory source and the component tool parts are constructed and related for optimum balance and operator control.

An important object, therefore, of the present invention is to provide a novel portable, motor powered, tool construction including a handle, a frame, and a vibrating implement, which construction is adapted for highly efficient and effective operation in performing a variety of tasks such as soil cultivation and aeration, paint scraping, fluid and solid matter agitation and the like.

Another important object of the present invention is to provide a novel portable tool construction of the above character which provides for easy operator handling and control by employing an overall lightweight and well balanced assembly.

Still another important object of the present invention is to provide a novel, portable, vibrating tool construction of the above character which employs a construction adapted to isolate the tool handle from the vibrating forces to further ease handling thereof and reduce operator fatigue.

Further objects of the present invention include the provision of a novel, portable, vibrating tool construction of the above character which is relatively compact and presents a neat and aesthetically pleasing appearance.

Still another object of the present invention is to provide a novel vibratory tool construction of the above character which employs a detachable implement adapted for easy change, removal and/or replacement.

Additional objects include the provision of a novel portable, vibratory tool construction of the above character which is relatively inexpensive to manufacture, rugged in construction and reliable in use.

Other objects and advantages of the present invention will become more apparent from a consideration of the detailed description to follow taken in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a motor powered, vibrating tool embodying the present invention;

3,530,577 Patented Sept. 29, 1970 'ice FIG. 2 is a longitudinal, vertical sectional view of the structure of FIG. 1 and illustrating a preferred form of the present invention;

FIG. 3 is an end view of the structure of FIG. 1;

FIG. 4 is a sectional view of FIG. 2 taken along the line 4-4 thereof;

FIG. 5 is a sectional view of FIG. 2 taken along the line 5-5 thereof;

FIG. 6 is a sectional view of FIG. 2 taken along the line 66 thereof;

FIG. 7 is an enlarged, fragmentary view, similar to FIG. 2, and illustrating a modified form of handle isolator;

FIG. 8 is a sectional view of FIG. 7 taken along the line 8-8 thereof;

FIG. 9 is a sectional view of FIG. 7, taken along the line 99 thereof;

FIG. 10 is a fragmentary view, similar to FIG. 2, illustrating a modified form of belt tensioning construction;

FIG. 11 is a partial perspective View illustrating a modified form of implement;

FIG. 12 is a partial elevational view illustrating a further form of implement;

FIG. 13 is a side elevational view illustrating a modified form of vibrating tool embodying the present invention; and

FIG. 14 is a partial plan view illustrating the frame and implement of the tool of FIG. 13.

BROAD STATEMENT OF THE INVENTION Broadly described, the present invention relates to a novel, portable, motor powered, vibrating tool construc tion and comprising a frame, a motor supported upon said frame and including an output rotatable shaft having a drive pulley fixed thereto, vibration inducing means including a rotatable unbalanced weight carried upon a driven pulley supported upon said frame remote from said motor, an endless 'belt interconnecting said drive and driven pulleys whereby energization of said motor is effective to vibrate said frame adjacent said inducing means, implement means interconnected with said frame for vibratory movement in response to action of said vibration inducing means, handle means interconnected with said frame adjacent said motor, and vibration isolating means between said handle means and said frame.

In another aspect, the present invention relates to a portable, motor powered, vibrating tool construction comprising a motor, an elongated frame extending away from said motor, vibration inducing means including a rotatable member supported in cantilever fashion upon said frame remote from said motor and adapted to be activated upon energization of said motor, implement means interconnected with said frame on the side of said inducing means remote from said motor for vibration in response to activation of said inducing means, said inducing means imparting components of vibratory translation to said frame generally in the plane of rotation of said inducing means and generally in a plane extending longitudinally of said frame.

In still another aspect, the present invention relates to a portable tool comprising frame means, an electric motor supported upon said frame means and having an output shaft rotatable about an axis, vibration inducing means supported upon said frame means at an area laterally spced from said axis and adapted to set up vibrations in a plane generally transverse to said axis, implement means rigidly fixed to said frame means at an area spaced laterally from said axis and said inducing means, transmission means interconnecting said output shaft and said inducing means whereby energization of said motor effects vibration of said implement through said inducing means and said frame means, and handle means interconnected with said frame means adjacent said motor.

DETAILED DESCRIPTION As used herein, the term tool construction refers to that class of hand held power driven devices for performing such tasks as soil cultivation, paint scraping, material agitation, etc. The terms implement, tool means or blade refer to that part of the overall tool construction which actually contacts the work during operational use.

Referring now more particularly to the drawings, a vibrating tool construction embodying a preferred form of the present invention is illustrated generally at 11 in FIGS. 1-3 and is seen to include an elongated frame 13 having a handle 15 secured to one end and a tool means 17 secured to the other end thereof. The frame 13 includes a hollow portion of L-shaped configuration having first and second legs 16, 18, and a solid shoe member which depends from the leg 18 and is secured thereto remote from the leg 16. A drive motor 19 is housed and supported in the frame leg 16 and vibration inducing means 21 is supported within the frame leg 18 at the end thereof remote from the leg 16 and is connected to the motor 19 by a transmission 23, the latter being entirely encased within the leg 18 (FIG. 2). The tool means or implement 17 includes a blade 27 secured to the outer end of the shoe 25. The handle 15 loosely embraces a portion of the frame leg 16 and is provided with a hand grip 29 having an on-off control switch 31 adjacent thereto and a conventional line cord 33 dependent therefrom.

The frame 13, in the embodiment of FIGS. 1-6, is seen to include a pair of mating, generally concave, frame members 35, 37 constructed of cast aluminum, magnesium or other suitable material and secured together in clam shell fashion along a longitudinal parting plane by screws 39. The motor 19 is provided with a rotatable armature shaft 41 supported fore and aft by bearings 43, 45 which are trapped between the frame members 35, 37. The motor 19 also includes stationary field laminations 53 which likewise are trapped between the frame members 35, 37. Preferably, insulating caps 55, 57 insulate the laminations 53 from the housing members 35, 37. A commutator 67 is fixed upon the armature shaft 41 and is engageable by a pair of electrical brushes 75, 77 carried by insulating brush holders 79, 81 each of which is trapped between the frame members 35,, 37 The brushes 75, 77 and the motor field are energized by way of electrical leads 83, 85 carried by the line cord 33 and another lead 87 interconnected therewith through the on-off switch 31 so that upon connecting the line cord 33 to an electrical source and closing the switch 31, the motor 19 is energized and the armature shaft 41 rotated. A fan 91 is pressed on and rotates with the armature shaft 41 to cause cooling air to move past the motor during operation of the device.

The armature shaft 41 extends through the bearing 43 into the frame leg 18 and has a drive pulley 93 threaded or otherwise secured thereon for rotation therewith. The drive pulley 93 forms a part of the transmission 23 and is connected by an endless belt 97 to a driven pulley 95 located near the other end of the leg 18. The driven pulley 95 is rotatably disposed on a stub shaft 99 and the latter is pressed into a bearing block 101 which supports the pulley 95. A retaining ring 103 holds the pulley 95 in place on the shaft 99 and bearing block 101 is detachably secured to the frame leg 18 by bolts 105 which are trapped between the frame members 35, 37 and trapped nuts 107. As shown in FIG. 2, the bearing block 101 has elongated apertures 106 through which the bolts 105 extend so that the block and therefore the pulley 95 are adjustable toward and away from the pulley 93 to adjust the tension in the belt 97.

As shown in FIGS. 2 and 4, the driven pulley 95 has an integral weighted portion 109 disposed eccentrically to its axis of rotation so that as the pulley rotates upon the stub shaft 99 and the bearing block 101, it imparts an orbital vibratory force to the bearing block 101 and therefore to the supporting frame leg 18. This causes the frame leg 18 to vibrate orbitally, particularly at that portion of the frame leg 18 adjacent the pulley 95. The shoe member 25 is detachably secured to the end of the frame leg 18 adjacent the vibration inducing device 21 by interfitting tongue- like projections 111, 112 on the shoe 25 and the frame leg 18, respectively, and by a strap 113 and screws 115 (only one of which is shown). The shoe 25 therefore vibrates under the action of the rotating eccentric weighted pulley 95 as does the implement or blade 27 which is detachably secured to the shoe 25 by screws 117.

Manifestly, because of the orbital vibratory force induced by the eccentric weighted pulley 95, the implement 27 undergoes a horizontal orbital mode or, stated another way, has a component of motion in an orbital path defined by a plane generally parallel to the plane of the pulley 95.

In addition, the blade or implement 27 suffers or undergoes a vertically nodding'rnode or moves alternately through a path lying in a plane which intersects the previously described plane.

The implement 27 is spaced appreciably from the pulley 95 both radially of its axis of rotation as well as axially of its plane of rotation. The forward, terminal portion of the frame leg 18 and the shoe member 25, which interconnect the vibration inducing pulley 95 and the implement, possess some degree of inherent flexibility, particularly because of their length so that when the pulley 95 rotates, this flexibility results in a vibratory component of movement of the implement 27 in a plane which intersects the plane of the pulley 95. Furthermore, the frame leg 18 is relatively long and is flexible to some extent. The eccentric weighted pulley 95 is supported upon the frame leg 18 in cantilever fashion by the stub shaft 99 and bearing block 101. The mass of the eccentric portion 109 of the pulley 95 is concentrated toward the up per, unsupported end thereof so that during pulley rotation, the shaft 99 flexes and a force couple is set up on the frame leg 18 during pulley rotation. This couple tends to flex or bend the leg 18 in alternate directions in a plane which intersects the plane of the pulley 95. The cantilever arrangement of the motor shaft allows it to flex in sympathy to flexing of the shaft 99 so as not to inhibit the latter.

Desirably, a plane which geometrically bisects the frame leg 18 along its length also bisects the shoe member 25 and the pulley 95 and is perpendicular to the plane of the latter so that the flexing action of the frame leg 18 coincides substantially with and reinforces the movement of the implement resulting from flexing of the shoe member 25. The result is that both flexing actions contribute to the nodding mode of the implement 27.

It will be understood that the amplitude of this nodding mode is a function of the length and inherent flexibility of the frame leg 18 and the shoe member 25. However, the total, resultant vibratory translation of the implement 27 is a complex path which is the vectorial sum of individual vibratory components occurring in mutually intersecting planes.

The implement or blade 27 illustrated in FIGS. l-3 is shaped in a fashion particularly adapted for soil cultivation and aeration purposes. Thus, the blade 27 is generally rectangular and has relatively deep, V-shaped recesses 119, 121 formed in its forward and rearward ends, respectively, so that it presents a plurality of exposed edge surfaces. In use, the blade 27 is imbedded in the ground with the exposed edge surfaces confronting the adjacent soil. The motor 19 is energized thereby rotating the pulley 95 and vibrating the implement 27. The vibratory translation of the implement vibrates and breaks up the soil into small particles so that it becomes aerated. As

the tool 11 is moved, the blade 27 of course moves and the soil set into motion around the blade edges becomes fluidized. This permits easy and relative free manual movement of the tool 11 along the area to be cultivated and, in addition, greatly enhances the agricultural qualities of the soil. Preferably, the blade edges are sharpened to further reduce the resistance thereof to movement through the soil.

In addition to fluidizing, aerating and in general loosening the soil, the vibratory modes suffered by the blade 27 enhances the capability of the tool for removing weeds and other undesirable objects from the soil. Thus, when the vibrating blade 27 engages the stalk of a weed, the weed begins to vibrate also and loosens within the soil. In addition, the soil around the vibrating blade is in a substantially fluidized state so that the weed can easily be withdrawn from the soil. Furthermore, the nodding mode suffered by the blade 27 tends to lift the soil, Weeds or any other objects which it engages thereby increasing the effectiveness of the tool for purposes of weeding, rock removal, etc. Advantageously, even though the blade 27 has sharpened edges, it will not cut either weeds or plants since by reason of the fluidized state of the soil around the plant and weed stalks, there is no reaction to the vibrating action of the blade 27 thereon so that no cutting action can take place. This also enhances the safety of the tool since it greatly reduces the possibility of injury to the user by touching the blade 27.

The vibration amplitude of the implement or blade 27 is, of course, dependent upon such factors as the weight of the eccentric portion 109 of the driven pulley 25, the flexibility and length of the frame leg 18 and the shoe 25, while the vibration frequency is dependent upon the rotational speed of the armature shaft 41 and the speed reduction ratio of the transmission 23. If desired, the frequency of the induced horizontal vibrational mode can be tuned to the natural frequency of the column formed by the frame leg 18 and the shoe between the driven pulley 95 and the blade 27 so that a resonant, reinforced vibration condition exists. The length of this column can be such that-it represents a multiple of half wave lengths so that an anti-node, or a point of maximum vibration amplitude occurs at the blade 27 thereby making the amplitude of blade translation a maximum. This natural frequency can be determined empirically or theoretically.

By way of example, it has been determined that for soil cultivation and aeration, a tool utilizing a pulley 99 weighing about 0.363 lb. and rotating at about 5000 rpm to give an orbital vibration frequency of from about to about cycles per second and a vibrational amplitude of from about to about inch produces good results. Highly satisfactory results have been achieved with a frequency of about 60 cycles per second and a vibration amplitude of about A inch; however, as described, these values are exemplary only and are not to be considered critical.

The vibratory force induced by the eccentric weight 109 tends to vibrate the entire frame 13 and together therewith, the handle 15 connected to the frame 13. However, the relatively great mass of the drive motor 19 at the end of the frame 13 remote from the pulley reduces somewhat the effect of the vibratory force at this end of the frame 13. In addition, the rotating parts of the motor 19 tend to remain stabilized in planes transverse to the rotational axis thereof by virtue of the angular momentum of the motor rotating parts which function somewhat in the nature of a gyroscope. The rotational axis of the motor parts is substantially parallel to the rotational axis of the eccentric weight 109 so that this angular momentum or gyroscopic action opposes the effect of the horizontal mode or vibrational component in the plane of the pulley 95. Also, if the natural frequency condition exists, the handle 15 could be connected to the frame 13 at a node, or a point of minimum vibration amplitude, in the latter which would ef- 6 fectively isolate the handle 15 from vibrations in the frame 13.

However, the frame 13 and the handle 15 are interconnected by a resilient assembly to help isolate the handle 15 from the vibrations in the frame 13. This handle 15, as seen in FIGS. 1-3, includes handle and handle cover portions 123, secured together in clam shell relation by screws 127. The handle and handle cover 123, 125 preferably are constructed from a moldable plastic material and serve to trap the electrical leads 83, 85, 87 and the switch 31 in place and clamps a bushing 124 on the line cord 33 therebetween. The handle 123 and cover 125 have abutting, substantially horizontal ledges 129, formed internally thereof and integral therewith, and the handle 123 and handle cover 125 cooperatively form a dependent skirt 131 adapted to loosely embrace the frame 13.

The frame members 35, 37, at the upper, terminal end of the leg 16, have abutting end walls 133, 134 forming a horizontal ledge which is substantially parallel to and spaced below the ledges 129, 130 on the handle 123. A pair of isolators 135, 137 interconnect the ledges 129, 130 and the end walls 133, 134, and therefore the handle 15 and the frame 13. These isolators 135, 137 include helically wound, stranded steel cables 139, 141 clamped between pairs of metal retainer plates 143, 145 and the latter are detachably secured to the ledges 129, 130 and end walls 133, 134 by bolts 147 and nuts 149. Isolators of this type are manufactured and sold by Aeroflex Laboratories Incorporated, Plainvie'w, N.Y., and provide a damping effect in three planes. In addition, these isolators have the unique characteristic of isolating the handle 15 from the induced vibrations in the frame 13 while providing a relatively stiff connection therebetween capable of transmitting operator thrust from the handle 15 to the frame 13 during use.

Another feature of the present invention resides in the structural arrangement which is calculated to provide optimum tool balance and control. Thus, the relatively large mass motor 19 together with the transmission 23 and the tool assembly 17 are positioned below the handle 15 and therefore are easily supported by the operator with one hand grasping the hand grip 29. In addition, the hand grip 29 is inclined and faces in the direction of the tool assembly 17 so that the tool 11 is easily moved forward and back as well as to either side.

FIGS. 7-9 illustrate a modified form of handle isolating construction. In this form, the handle 15 and frame 13 are interconnected by three isolators 151, 153, 155, each of which is secured to the frame leg 16 and includes a rubber or rubber-like sleeve 157 having a pair of rigid plates 159, 161 secured in spaced relation within the ends thereof. Each of the plates 159, 161 has a threaded post 163, 165, respectively, secured thereto or integral therewith and extending outwardly at the ends of each isolator 151, 153, 155. The posts 165 of the isolators 151, 153 extend between the housing end walls 133, 134 at the parting plane therebetween and may have a nut 169 threaded thereon and trapped between the end walls 133, 134. The post 165 on the isolator extends through a lateral plate 167 fixed to or integral with frame leg 16, and is secured in place by a nut 168. The posts 163 of each isolator 151, 153, 155 extends through a bent arm 171 and is secured thereto by nuts 173. The arm 171 is provided with a pair of rearwardly bent flanges 175, 177 near its lower end, which have a bolt 178 extending therethrough and through aligned openings 181, 183 in the handle and handle cover 123, 125, the bolt 178 being secured in place by a nut 184. Also, the upper end of the arm 171 is secured to the handle 123 and handle cover 125 by screws 182 threaded into bosses or nuts 184 secured to or integral with the arm 171 and located on either side of the isolator 151. Like the isolator construction described above for FIGS. 1-6, this construction through the rubber or rubber-like sleeves 157, permits limited universal relative movement between the handle and the frame 13 but provides a relatively stiff connection therebetween capable of transmitting operator thrust during use. In all other respects, the details of the tool construction in FIGS. 7 and 8 is the same as that illustrated and described for the embodiment of FIGS. 1-6.

FIG. 10 illustrates a modified form of belt tensioning device and a modified frame construction. Here, the bearing block 101 is biased in a direction away from the driven pulley 93, or in a right hand direction as seen in the figure, by a compression spring 187 caged between a pocket 189 on the housing leg 18 and the bearing block 101. The compression spring 187 desirably is constructed to set up the desired tension in the belt 97 so that when the parts are assembled, the bearing block 101 will be properly positioned automatically and the bolts 105 need only be tightened. The modified frame construction, illustrated in FIG. 10, shows the foot member A, to which the implement 27 is secured, as integral parts of the clam shell frame members 35, 37, respectively, and carrying one of the connecting screws 39.

As described above, the blade or implement 27 illus trated in FIGS. 1-3 is constructed and particularly shaped for advantageous use in cultivating and aerating soil. For other uses, such as paint scraping, stirring, and the like, other blades or implements may be substituted for the pointed blade 27. For example, a chisel edged or convex shaped blade 27A, shown in FIG. 11, will find use in surface scraping applications such as paint removal. Also, a relatively blunt faced, generally cylindrical implement 27B, shown in FIG. 12, will be useful for stirring or agitating fluids or solids. Other types of blades useful in still other applications will be readily apparent to those skilled in the art and it is to be understood that the blade illustrated is given by way of example only.

FIGS. 13 and 14 illustrate a modified form of tool construction. This device, illustrated generally at 201, includes an elongated frame 203 which preferably is constructed of a relatively strong and flexible material such as, for example, spring steel. The frame 203 has an electric motor 205 suitably secured thereto at one end and an implement or tool 207 integral with or otherwise fixed thereto at the other end thereof. The motor 205 has an output shaft 209 with a drive pulley 211 secured thereto for rotation therewith. A driven pulley 213 is rotatably supported by a shaft 215 on the frame 203 at a point remote from the pulley 209, and a belt 217 interconnects the pulleys. The driven pulley 213 may be eccentrically weighted, like the pulley 95 in the previous embodiments, so that when rotated, the pulley 213 imparts vibrations to the frame 203. The frame 203 is, of course, flexible, the shafts 209, 215 support the pulleys 211, 213 in cantilever fashion and the blade 207 is spaced downwardly and forwardly of the pulley 213 so that the blade 207 undergoes vibratory translation in much the same fashion as, but perhaps to a greater extent than, the blade 27 in the embodiments of FIGS. 1-10. A suitable handle 219 is fixed to the motor 205 for control and manipulation of the tool.

By the foregoing, there has been disclosed an improved portable, vibrating tool construction calculated to fulfill the inventive objects hereinabove set forth, and while a preferred embodiment of the present invention has been illustrated and described in detail, various additions, substitutions, modifications and omissions may be made thereto without departing from the spirit of the invention as encompassed by the appended claims.

We claim:

1. A portable, motor powered vibrating tool construction comprising a frame, a motor supported upon said frame and including an output rotatable shaft having a drive pulley fixed thereto, vibration inducing means including a rotatable unbalanced weight carried upon a driven pulley supported upon said frame remote from said motor, an endless belt interconnecting said drive and driven pulleys whereby energization of said motor is effective to vibrate said frame adjacent said inducing means, implement means interconnected with said frame for vibratory movement in response to action of said vibration inducing means, handle means interconnected with said frame adjacent said motor, and vibration isolating means between said handle means and said frame.

2. A portable, motor powered, vibrating tool construction comprising a motor, an elongated frame extending away from said motor, vibration inducing means including a rotatable member supported in cantilever fashion upon said frame remote from said motor and adapted to be activated upon energization of said motor, implement means interconnected with said frame on the side of said inducing means remote from said motor for vibration in response to activation of said inducing means, said inducing means imparting components of vibratory translation to said frame generally in the plane of rotation of said inducing means and generally in a plane extending longitudinally of said frame.

3. A portable tool comprising frame means, an electric motor supported upon said frame means and having an output shaft rotatable about an axis, vibration inducing means supported upon said frame means at an area laterally spaced from said axis and adapted to set up vibrations in a plane generally transverse to said axis, implement means rigidly fixed to said frame means at an area spaced laterally from said axis and said inducing means, transmission means interconnecting said output shaft and said inducing means whereby energization of said motor effects vibration of said implement through said inducing means and said frame means, and handle means interconnected with said frame means adjacent said motor.

4. A tool as defined in claim 3 wherein said vibration inducing means includes rotatable means.

5. A construction as defined in claim 3 wherein said frame means includes first and second legs, said motor being supported upon said first leg, and said vibration inducing means being supported upon said second leg at the end thereof remote from said first leg.

6. A construction as defined in claim 3 wherein said frame means includes first and second, generally concave, clam shell members detachably secured together along a longitudinal parting plane, said frame means having first and second legs encasing said motor and vibration inducing means, respectively, said frame means further including a foot portion adapted to have said implement secured thereto.

7. A construction as defined in claim 1 wherein said Weighted pulley is rotatably supported by a stub shaft having one end fixed relative to said frame, the other end of said shaft being free.

8. A construction as defined in claim 1 which includes a bearing block fixed to said frame, said stub shaft having its one end fixed within said bearing block, said weighted pulley being supported upon said bearing block.

9. A construction as defined in claim 8 wherein said bearing block is adjustable upon said frame toward and away from said drive pulley to vary the tension in said belt.

10. A construction as defined in claim 9 which includes spring means carried by said frame and engaging and normally biasing said bearing block in a direction tensioning said belt.

11. A construction as defined in claim 3 wherein said frame means includes a detachable shoe adjacent said vibration inducing means and an implement detachably secured to said shoe.

12. A construction as defined in claim 4 wherein said tool means includes a generally fiat blade, said rotatable vibration inducing means adapted to impart to said blade a component of motion in an orbital path substantially in the plane of said blade, and another component of motion generally transverse to said orbital path.

13. A construction as defined in claim 3 wherein said implement is fiat and generally rectangular in configuration and has sharpened front and rear edges.

14. A construction as defined in claim 3 wherein said implement is generally cylindrical in cross section.

15. A construction as defined in claim 5 wherein said vibration inducing means includes rotatable means sup ported upon said second frame leg and is effective to vibrate said second frame leg other end and said implement imparting to it a component of motion in a plane substantially transverse to the axis of rotation of said vibration inducing means and another component of motion in a plane including said axis and intersecting said first mentioned plane.

16. A construction as defined in claim 15 wherein said implement is spaced transversely from said second leg and is operatively connected thereto adjacent said vibration inducing means.

17. A construction as defined in claim 5 wherein said handle means is disposed above said first frame leg, said handle means having a hand grip disposed above and to the side of said first frame leg opposite said second frame leg.

18. A construction as defined in claim 5 wherein said handle means is disposed above said first frame leg, and

References Cited UNITED STATES PATENTS 1,927,075 9/ 1933 Thomas 7487 2,080,921 5/1937 Jackson 17349 2,155,713 4/1939 Iargick l73162 2,350,098 5/1944 Decker 51-1703 2,951,479 9/1960 Sneller 7487 X 3,409,056 11/1968 Rauh l7316'2 X ROBERT C. RIORDON, Primary Examiner R. V. PARKER, IR., Assistant Examiner US. Cl. X.R.

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