CA1093843A - Rotary cutting assembly - Google Patents

Abstract

A B S T R A C T

This invention is for an improved cutting assem-bly for a rotary mower, edger, trimmer or the like. It includes a body member arranged for rotation about an axis generally perpendicular with or normal to the cutting plane. It preferably includes one non-metallic cutting line attached to the body member at three alternate sites for rotation therewith in the cutting plane, although a pair of lines may be effective for present purposes under proper circumstances. More particularly, provision is made via metallic bearing surfaces for the reduction of friction between the cutting lines and portions of the apparatus and between adjacent portions of the cutting lines, and for higher speed and cutting efficiency.

Description

3~3 IMPROVED ROT~RY CU'l"rING l~SSFM13LY

BACKGROUNr) OF Tlll. INVE:NTION
-This invention rela-tes to apparatus for cuttlny vegetation and -the like, and more particularly relates to improved apparatus for cutting vegetation with a flexible non-metallic cord member.

It is well known to cut or mow grass, weeds and other vegetation with a moving flail~ e menl~er, ancl it is now well known to employ a flexible non-metallic cord member for the purpose of cutting vegetation located in places which are inaccessible to apparatus elllylo~ing a rigid steel blade. In particular, the trimmer wllich is marketed in various forms under the trademark WEED EATER, and which is described in UO S. Patents No. 3,708,967;
No. 3,826!068; and No. 3,859,776; is now widely known and used for this purpose.

This invention relates to an improvecl ~ ttill~l assembly in the orm of a ro-tary head for a rotary edger, ;`
trimmer or the li~e. The preferred embodiment is in the form of a portable hand-held type mowing and edging tool ~ ~
wherein the cutting element is safe in most uses and avoids ,;
hazardous conditions.
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S~1MMARY OF T~IE INVENTION
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Incne broad aspect, -the invention comprehends an apparatus for cu-tting vegetation and the :like, W]liCIl comprises head means rotatable ahout a rota-tional axis in a cutting plane which has a concentrically located open-end storage portion for a spool means and a peripherally located support portion having a solid curvilinear bearing surface.
Drive means rotate the head means in the cutting plane, and a flexible non-~etallic line member has a coiled portion in the storage portion of the heacl mealls, and furt~cL-Ilas an uncoiled portion extending from the coiled portion into -the cutting plane to and across the bearing surface and further continues radially outwardly from -the periphery of the heacl means. Spool means are insertable in the storage portion of the head means through the open end and hold the coiled portion of -the line member in the head means. Tab means and a keyway associated with the head means and spool means are adapted to be axially interfitted and rotationally interlocked whereby an axially and radially secure inter-connection is provided between the spool means and head means.
The inven-tion further comprehends an apparatus Eor cutting vegetation and the like, which comprises disc-like means rota-table about a rota-tional axis in a cuttlng plane and having a concentrically located open-ended storage portion for spool means and a peripherally located support portion having curvilinear bearing surfaces defining one or more peripheral apertures. Drive means rotate the head means in the cutting plane, and a flexible non-metallic line member has a coiled portion in the storage portion of the head means and further has an uncoiled portion extending from the coilecl portion into the cutting plane to and through at least one of the . ,~,., ~ .

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peripheral apertures and further continues radially outward from the periphery of the head means. Circular spool means are insertable axially agains-t an abutment surface in the storage portion oE the head means through -the open end and holding the coiled portion of the cutting :Line, the spool means including first tab means associated therewith. Second tab means on the head means are in the storage portion and cooperate in angular interfitting with the first tab means to lock the spool means in the s-torage portion o.~ tlle head means. Metallic bearing elements include portions in abu-t-ting relationship to the curvilinear bearing surEaces of each of the peripheral apertures, and central gu.ide means on the spool means and head means position the spool means coaxially in the head means and with the first tab means in angular alignment with -the second tab means. The spool means are rotated inone direction a~ partial turn a~out tlle rotatioll-al axis relative to the head means to interfit the second tab means and the first tab means whereby the spool means is locked within the head means against unintended axial and radial displacements but reverse rotation of -the sPool means over the par-tial turn releases the spool means for ready axial removal from the head means.

_N THE DRAWINGS
Figure 1 is a pictorial view showing a first embodiment of a cut-ting apparatus.
Figure 2 is a pictorial side view, partly in cross-section, of -the apparatus depicted in Figure 1, wherein the mechanical features and configuration of the apparatus are set forth in ~reater detail.

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3~3 . .:`' Figure 3 is an exploded assembly drawing of one embodiment of the head and spool assembly useful in the apparatus of Figures 1 and 23.

Figure 4 is a cross-sectional view of the head assembly depicted in Figure 3 in a static or nonrotating position showing the cutting string moun-ted therein.

Figure 5 is a bottom view of the spool assembly depicted in Fiyure 3.

Fiyure 6 is a top view of -the spool depicted in Figure 3.

Figure 7 is a bottom view of the head depicted in Figure 3.

Figure 3 is a top view of the head depicted in Figure 3.

Figure 9 is a side view of the vaned head of Figure 8 in a s-tatic or nonrotating posi-tion.

Figure 10 is a partial side view representation of one embodiment of a cutting string aperture.

Figure 11 is a similar partial side view repre-sentation of another embodiment of a cutting string aper-ture.

Figure 12 is an alternate three window~ed embodi-ment of the apparatus depicted in Figure 7.

Figure 13 is an alternate three windowed embodi-ment of the apparatus depicted in Figure 8.

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~3~'~L3 Figure 1~ is a par-ti~1 view showing the portable apparatus of Figure 1 being used to cut grass or weeds in the upright level position.

Figure 15 is a similar partial view showiny the apparatus of Figure 1 being used to cut in the perpendicular or sideways position.

Fiyure 16 is a partial cross-sectional view of the handle of the apparatus oE Figures 1 and 23 showing the attitude-adjus-ting mechanism for positioning of the cutting head as shown for example in Figures 14 and 15 Figure 17 is a cross-sectional view taken along line 17-17 of Fiyure 16 showincJ the attitude-adjustincJ
mechanism of the handle of the apparatus.

Figures 1~ a~d 19 are partial side views of the housing of the apparatus of Figure 2 and showing details of a knife assembly for the manual cutting of the line member.

Figure 20 is a partial front view of -the knife assembly of Figure 19 and taken alony the line Z0-20 thereof.

Figure 21 is a bottom view of the housing of the Z0 device depicted in Figure 2 ancl showiny the de-tails of the second knife me}nber for automatically cutting the line mem-ber when the device is in operation.

Figure 22 is a partial isome-tric view of the details of the automatic knife cutting member depic-ted in Figures 2 and 21.

~3~1L3 Figure 23 is a pictorial side view, partly in cross-section, of another embodiment of the apparatus wherein the mechanical features and configuration of the apparatus are set forth in detail.

Figure 24 is a top plan view of the head men~er depicted in Figure 23.

Figure 25 is a bottom plan view of the head mem-beF depicted in Figure 24.

Figure 26 is a cross-sectional view of the head assembly depicted in Fiyure 23 in a static or nonrotatinq position showing the cutting string mounted therein.

; Figure 27 is an exploded assembly drawing of the head assembly of Figure 26.

Figure 28 is a top plan view of the spool depicted in Figure 27.

Figure 29 is a side plan view of the spool de-picted in Figure 27.

Figure 30 is a cross-sectional side view of the spool depicted in Figure 27 and taken along line 30-30 of ; 20 Figure 29.

Figure 31 is a bottom plan view of the spool de-picted in Figure 27.

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Figure 32 is a top plan view representation of the unitary bearing elemen-t illustrated in Figure 27.

Figuxe 33 is a pic-torial side viewl par-tly in cross-section, o~ yet ano-ther embodiment of the cutting apparatus, wherein the mechanical ~eatures and confiyura-tion of the apparatus are set forth in detail.

Figure 34 is an e~ploded assembly drawing of one embodiment of the head and spool assembly in Figure 33.

Figure 35 is ~ top view of the head depicted in Figure 34, appearing with Fiyures 33 and 36.

Figure 36 is a bottom view of the head depicted in Figure 34, appearing with Figures 33 and 35.

Figure 37 is a cross-sectional view of the head assembly deplcted in Figure 34 in a static or nonrotating position showing the cutting string mounted therein.

Figure 33 is a bottom view o~ the insert depicted in Figure 34.

Figure 39 is a bottom view of the locking clip depicted in Figure 34. :~

Figure 40 is a top view of the spool depicted in Figure 34.

Figure 41 is a bottom view OI the spool depicted in Figure 34.

Figure 42 is a side cross-sectional view of the spool depic-ted in Figure 34. :

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Figure ~3 is an exp]oded assembly drawing of an alternate embodiment of the head and spool assembly depicted in Figure 34.

Figure 44 is a top view of the head depicted in Figure 43.

Figure 45 is a bottom view of the head depicted in Figure 43.

Figure 46 is a top view of the spool depicted in Figure 43.

Figure 47 is a bottom view of the spool depicted in Figure 43.

Figure 48 is a cross sectional view of the alternate head assembly depicted in Figure 43 in a static or nonrotating position showing the cutting string moun-ted therein, appearing with Figure 43.

Fiqure 49 is a bottom view of the inser-t depicted .in Figure 43.

DETAILED DFSCRIPTION :

Referring now to Figures 1 - 2, a por-table type mowing and edging device generally designated by the numeral

2 is shown, and which is of the type preferred for lighter tasks -in residential-size plots or areas, and the like, where electri-cal power is immediately and conveniently available to the operator. Accordingly, the apparatus may

3~L3 be composed of a two-piece adjustable tubular member 4 and 6 havinc3 a casing 8 containing electric motor 10 mounted at one end, wllich motor drives a striny cutting head 42.
The member 6 i.s .removabl~ ~ttached to and sup~orts casing 8 by screws 15 insertable .in shank 14. Such a device is portable and is hand he1d and manipulatecl by an opera-tor by means of trigger handle 16 ancd intermediate handle 18.
Ilandle 16 is attached to tubular member 4 by screws 25, whereas handle 18 is attached to tubular member 4 by an easily adjustable wing-nut assembly 27. Power may be applied to the motor 10 through a conventional electrical-type .insul-ated cord or conductor 20, having an apE~ropriate plug at one el~cl (not shown), and having its other end passecl throuyh the tubular members 4 and 6 Eor connection willl the rnotor 10 by means of connectors 17 and 19 at contac-ts of a full-wave bridge rectifier 21. An appropriate ON-OFF switch or trigger 22 may conveniently be located adjacent -the hanclle 16 at the upper end of -the tubular member 4, for interconnection with -the conductor 20 and motor 10. rlhe cutting plane o:E the cutting string 26 may be easily arrang-ed in either a horizontal or vertieal positlon (Figures 14 and 15) or tilted tG any angle, to cut along sidewa~.ks, around trees and rocks, and along fences and the like, where it is either unsafe or difficult to cut with conven-tional apparatus, merely by.turning and manipulatincJ llalldles : 16 and 18. ~dditionally, an attitude adjustment mecllanism 98 may be provided to enable tube member 6 to telescopically, rotatably anc3 increlllentally lock with respect to tu~e mem-ber 4, wherein an operator may adjust the attitude of the cutting ilead in relation to the grounc3, as will be describecl in more detail hereafter with regard to ~igures 16 and 17.

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~ 3~l3 Referriny rnore part:icularly to F'igure 2, there may be seen a larger and more de-tailed pictorial represen-tation of the apparatus depicted more generally in Figure ~ lore particularly, the apparatus or vegetation cut-ter 2 depicted therein may be seen to include a hollow casing 8 or the like, with a single string circular cut-tinq head 42 which is rotatecl by the shaf-t 36 of an electrical motor 10 of suitable design mounted within casing 8. Casing 8 in the ernbodiment of Figures 1 and 2 also carries a manually operable knife 7 for cu-tting strand 26 to length prior to operation of the device. This cutting knife 7 will be described in more detail hereinaf-ter with reference to Figures 18 ~ 20.
The cutting head 42 may be Eurther seen to include cutting strand 26 extending laterally from the cutting head 42 through either aperture 60 or 62 (Figure 3) of sui-table configuration, a distance which is a function of the present invention as will hereinafter be explained. ~s fur-ther inclicated, the casin~ may have an oval or tear-dropped shaped interference guard or shield member 30 which in the ernbodiment of Figures 1 and 2 mounts at one end thereoE a stationary cu-ttiny blade 37 described in more de-tail herein-after with reference -to Figures 21 and 22. The interference member preven-ts the cu-tting head 42 from being brought into injurious contact with a wall or tree during its rotation by motor 10.
When the Motor 10 is inactivated and,the rotarY
head 42 is in a static condition, the cuttinq s-trand line 26 will tend to flexibly danqle from one of the equally spaced-apart windows 60 and 62 (Fiqure 3) to the extent permitted by inheren-t ch~racteristics of line 26. When the cuttinq head ......

~3~'~3 42 is rotated at normal operatinq velocities, however, the line 26 will tend to stand out riqidly (but also flexibly and yieldably) from -the periphery of the cutting head 42 as indicated in Figures 1 - 2.
As will hereina~ter be explained in grea-ter de-tail, a spool containing surplus line is removably insert-ahle into cutting head 42, and held in place by glide ball 32. In addition to securiny the spool in place, glide ball 32 allows the device to be operated, if desired, without having to be continually and solely supported by an oper-ator. The device 2 may be rested and propelled Eorward on the cJlide ball 32 when in operation iE this type oE cut-ting is found to be desirable. G~nerally the unit is sup-ported by the operator at handles 16 and 18.
The electric motor 10 operates in an optimum manner when the air around it is allowed to be circ~lated or otherwise cooled. The hollow casing 8 effectively allows air to freely circulate around motor 10, therefore provid-ing forced air circulation. The plurality of ups-tanding fins 28 located on the top of cut-ting head 42 ancl extending radially outward from the axis thereof provide Eorced cir-culation of air about motor 10 when motor 10 rotates head - ;
42. Rapid rotation of head 42, and hence of fins 28, causes said fins to create a low pressure zone within casing 8, whereby air is drawn from the atmosphere through either openings 34 in lower tubular member 6 or through slots 35 in shank 14, and passed through shank 14, casing 8, and around the mo-tor 10, and expelled through the space 38 be-tween shield 30 and cutting head 42. This circulation of 38~

air sufficiently cools motor 10 to provide maximum effi-ciency and minimal ambient heat rise. Moreover, the open-ings 34 and slots 35 are sufficiently remo~ed from the cut-ting area that cut grass or other debris flung up by line 26 is not likely to enter openings 34 and slots 35 along with the air. ~~

The cutting line 26 may be composed of a variety of suitable materials as, for example, an elastoplastic extrusion which has been stretched to align the molecules axially. An example of such line is a nylon monofilament of the type commonly used for fishing line. ~lowever, other lines may be used, as for example, yarn, cord, rope, twine, braided line, or monofilament, whether described as elas~o-plastic, elastomeric, natural fiber, or synthetic fiber, and whether compounded of several materials.

Referring now to Figures 3-9, it may be seen that the lower end of the drive shaft 36 ~rom motor 10 is arranyed for threading engagement with a drive adap-ted or attachment member 36A. Drive adapter 36A extends downwardly through head 42 and is arranged at i-ts lower extremity for threading arrange-ment with glide ball 32. Drive adapter 36A inserts tightly into head 42 and retains its relationship with head 42 by means of its hexayonal head 40 which is insertable into head 42. Rotation of drive adapter 36A by drive shaft 36 causes head 42 to rotate, thereby extending the string 26 to perform a cutting function.

Glide ball 32, in addition to engaging drive adapter 36A and securing said drive adapter 36A in relationship with head 42 so as to provide axial rotation thereof, also releas-ably secures spool 44 within head 42 as shown in Figure 4.
Spool 44 contains spare cutting line 46 therein, which is arranged ~or paying ou-t at predetermined times and at pre-3~

determined lengths to vary the effective working length ofthe cutting line 26. Removal of glide balL 32 by unthreading from drive adapter 36A allows removal of spool 44 so that a fresh full spool may be reinserted into head 42, or alternatively spool 44 may be rewound with new replace-~3&~

ment line, or the like. The external circumference of glideball 32 may be provlded with equally spaced-apart vertical lineal pro-trusions 33 to insure a better grip Eor easier removal. Holes 64 and 66 as seen in Figures 7 and 8 are provided in head 42 so that after glide ball 32 ls rernoved from dri.ve adap-ter 36A, spool 44 may be more easily rernoved from head 42 by pressing manually with a finger or other object through tlle holes 64 and 66 to thereby force the spool 44 to disengage from head 42.

Spool 44 as seen in ~igures 3, 5, and 6 is com-posed of a bottom wall 48 and a top wall 50 spaced a l~redeter-mined distance by annular hub 52. Interior oE hub 52 is an aperture 54 in wall 48 through whicll drive adapter 36A
passes when threaded into glide ball 32. The spool top wall 50 has insert knobs or ridge members 56 and 58 which corres-pond to and inser-t into window apertures 60 and ~2 in head 42 when spool 44 is placed within head 42. ~nobs 56 and 58 position.spool 44 and close or seal off the bottom of window apertures 60 and 62, whereby the cuttinc~ e 26 :is effec-tively prevented from being deflected vertically as will hereinafter be more fully explained. The spool bottom wall 48 is provided with cylindrical alignment pro-tuberance tabs 68 and 70 extending downwardly therefrom. When the spool 44 is placed within head 42, the tabs 68 and 70 har-moniously insert into corresponding cylindrical depressions ; or detents 72 and 74 in head 42 as seen in Figure 7, thereby positioning and further securing spool 44 therein for rota-tion alony with head assembly 42, .~
Refexring now to Figures 12 and 13, there may be seen a top and bottom view of ano-ther embodiment of the -- 1~ --. --3~13 present invention. In particular, -the depicted head 80 may be seen to be generally simi.l.ar to -the head 42 illus-trated in Figures 3, 7, 8, and 9. The principal difference, however, may be seen to be -the :fact that, in the head 42 previously described, the head is preferably provided with two window apertures 60 and 62 wherefrom a cutting string may protrude. The head depicted in Figures 12 and 13, how-ever, is preferab:Ly provided with three window apertures 102, 104, and 106 equally spaced-apart around the circumfer-ence of head 80, from either of whicll a cutting string maybe extended. It can re~dily be seen tilat use of the three-window aperture heacl 80 requires moclifi.catioll Oe spool 44.
More particularly, use oE heacl 80 requires that three insert knobs 56, 57 and 58, be located on spool top wall 50 as illustrated for example in Figure 21, so that the three knobs may correspond to and insert into window apextures 102, 104 and 106. In addi-tion, the spool bottom wall 48 is modi-fied to provide three cylindrical alignment protrusiolls ex-tending there:~rom, similar to the pro-trusions 68 and 70 of Figure 6 hereinbefore described which protrusions harmoniously insert into the corresponding cylindrical depressions 82, 84 and 86 of Figure 12.

It may be clearly seen in Figures 3 - 4, -that in one embodiment a single line 26 extends from -the body of the cutting head 42, and through one of the -two ~indow apertures 60 and 62. In the embodiment therein depicted, one end of the line 26 is inserted through aperture 55 in the spool hub 52, and then knotted together to prevent dis-engagement therefrom. The line 26 is -then preferably ~Jound about the spool 44, oppositely oE the ~]irecti.on of rotation of spool 44 and head 42, and then extended throuyh one of respec-tive window apertures 60 and 62, as hereinbe~ore stated.

The line 26 may be unwound and paid out Erom -the spool 44 without rernoving -the spool 44 from the head 42, by drawiny it from one of respective window apertures 60 and 62 and simply pulling down on the line 26 to -the next window aperture. This movement of line 26 from aperture to aperture is made possible by virtue of tlle fact that the top wall 50 of the spool 44 is stiff but resilient. It is -to be noted, -that a spool modified as hereinbe~ore described for use with the embodiment oE the cutting head depicted in Figures 12 and 13, may be simi:l.ar:ly wouncl an(] unwou~d with cutting line. In an alternate embodiment o~ the present invention, a pair of cutting lines 26 may be provided but no additional structure is required to provide this dual cutting line feature. For example, and in ligh-t of Figures 3 and 4, the empty spool 44 is wound as above. However, in the dual cutting line embodiment, the line 26 is first doubled along its length thereby providing -two free ends. That portion of the line that is doubled is inserted throuyh aperture 55 and knotted as above. The doubled line is -then wound onto the spool until the two free -travelling ends are reached. Each free end of -the line 26 is then extended through one of the respective window apertures 60 and 62, thus providing a head assembly 42 including a pair of cutting strands 26. To ex-tend either of the lines, it is then merely required to pull down on the line as seen in Figure 4 until that line reaches the next window aperture. Since wall 50 is resilien-t, the line can be pulled along the space defined by wall 50 and the inner periphery of head 42 until it reaches the next ' ~....... . .~,:

~3~3 window aperture. The other line may be extended or paid out in similar fashion. While two cutting lines m~ simi-larly be provided in the three exi-t head arrangement depicted in Figures 12, 13 and 21, use of plural lines is not con-sidered altogether desirahle in this particular em~odiment since no two of the exit window apertures 102, 104 and 106, are diametrically opposed one to -the other. ~he use of three cutting lines, however, in this particular embodiment is contemplated, although a sinyle line 26 has been found to be entirely sufficient for the majority of purposes to which this apparatus is put -to use in vege-tation cu-tting operations.
Referriny now to Figure 3, the two window aper tures 60 and 62 are each composed oE a pair of curvilinear and spaced apart sidewalls 61 and 61A. In -this embodiment oE
the present invention, the cutting line 26 is composed of a coiled portion 46 (Figure 4) wound about the spool ~4, and a free travelling end portion extending along a tangent thereto outwardly through one of the respective window aper-tures 60 and 62. Accordingly, the line tends to abut -the trailing one of the pair of sidewalls 61 and 61A composiny the respec-tive one of the two windows 60 and 62, rather -than the sidewall which leads the line as it is carried arcuately about by rota-tion of the cutting head 42.

It has been found beneficial to provide these trailing sidewalls with metallic bearing element~inser-ts 76 and 78 prefereably formed of a material which has a reduced tendency to develop friction from engagement with the vibrating cutting line, and further preferably having a smooth or polished surface for carrying the cutting line. These inserts 76 and 78 ~3~3 may be formed by a variety of different materials which axe suitable for such purposes, but it has been found that a polished metal such as brass or stainless steel is especially suitable.

Referring now to Figures 10 and 11, it may be-seen that the windows 60 and 62 of Figure 3 may be altered in design so as to provide bulbous shaped aPerture.s 88 or 90 as shown, or any other similarly shaped aperture. Rapid revolution of head 42 will force cutting line 26 into con-stricted portions 92 or 94, thereby reducing the up and downdeflection of the cukting line 26 in the vicinity of the windows 88 or 90. Furthermore, the bearing inserts 76 and 78 (Figure 3) as hereinbefore described may be suitabiy shaped and inserted into the bulbous windows 88 or 90. It is to be noted that the alternate embodiment of the head 80 depicted in Figures 12, 13 and 21, may likewise employ bulbous window configurations 88 or 90 disclosed herein.

Referring now to Figures 14 and 15, two posi-tions or attitudes for operating the device 2 are depicted. Figure .. . .

~Y13~'~3 14 shows a partial view of device 2 being operatecl in a hor-izontal position with the cutting path described by cuttiny line 26 being essentially parallel ko the ground. The lower portion oE the handle 6 is shown supporting casing 8 by means of shank 14. Cutting head 42 is shown with cutting line 26 extending therefrom. In actual practice, much of the grass or weeds -to be cut will be close to the ground, and therefore the device 2 will have to be tilted slightly to cause the cutting string 26 to Cllt. In this regard, ylide ball 32 may be used to allow the unit to "ride" the ground as the cuttiny operation takes place, and the convex outer lower shape of the ylide ball 32 enables an operator to COtl-veniently tilt the unit 2 to any desired anyle.

Referring more particularly to Figure 15, the unit 2 depicted in Figure 14 is shown in the alternate ver-tical attitude. The device 2 may be used in this attitude to trim areas o-therwise no-t accessible, trim in a straight line by "trenching" a grass plot in the conventional manner, or the like.

Proper manual manipulation of handles 16 and 18 (Fig. 2) of apparatus 2 may result in either a horizon-tal or vertical cutting attitude as hereinbefore described and depicted in Figures 14 and 15. However, attitude adjus-ting means 98 as shown in Figure 16 may be incorporated be-tween upper and lower -tubular rnembers 4 and 6, respectively, to facili-tate attitude adjus-tment by allowing tubular mem-bers 4 and 6 to be axially rotated and -telescopically arxanged wi-th respect to each other in increments of 90.

Referring more particularly to Figures 16 and 17, upper tubular member 4 is shown terminating at its lower end 108 in a tubular insert 110 suitably permanently affixed thereto. Inserts 110 and 11~ are axially alic1ned, and insert 110 extencls beyond member 4 and inserts snuyly but slidably in-to insert 114. Near -th~ lower extremity oE slidable insert 110 and aEfixed thereto are two protruding knobs 116 and 116A, rectangular in cross-sec-tion, and releasably retained by slots 118A - D, whereby insert 110 may be rotated axially within insert 11~. Spring 120 is axially al.iyned and con-tained within tubular member 6 between insert 110 and washer 122. Washer 122 retains spring 120 in place, alld is itself-retained in positi.on by a crimp 12~ in t~le ci.rcum.Eerellce o.E tubular meTnbe~r 6. F.lectrical hclrlless assembl.y 20 may be seen extending substantially throuyh the center of aper-ture 126 in washer 122, and Eurther through the axial center of spring 120, then throuyh the axial centers of inserts 110 and 114, and finally through the axial centers of tubu-lar members 4 and 6. Thus, it will be apparent -that down-ward pressure in the axial direction on upper tubu.l.ar member ~ and hence on insert 110, su.Eficient to overcome the upward bias exerted by spring 120, will cause tubular members 4 and 6 to converge and telescope until annular sur:Eaces 130 and 132 contac-t. Knobs 116 and 116A will then be forced downwardly sufficiently to be disengayed from slots 118A
and 118C. In thls compressed mode, tubular members 4 and 6 may be axially rotated in opposi-te directions sufficient to rota-te knobs 116 and 116A 90 within member 6 and aliyn them with slots 118B and 118D. Removal of the downward pres-sure will cause spring 120 to Eorce insert 1]0 and membe.r

4 upward again and -to slide knobs 116 anci 116~ into slots ~ 3~L3 118B and 118D. In this manner, tubular member 4 may be rota- :
ted in 90 increments with respect to tubular member 6, thereby enabling an operator to choose .between a horizontal (E'igure 14) or vertical (Figure 15) cutting attitude while retaining handles 16 and 18 in the same convenient easy -to hold position shown in Figures 1 - 2.

With reference again to E'igures 12 and 13, a further Eeature of the present inyention includes means where-by the three exit head embodiment may be balanced rotation~
ally so as not to transmit unwanted vibrations to the motor sha.ft 36. Thus, to provide a smooth running and rotationally balanced head assembly 80, i~ is necessary to o.Efset the weight attributable to the line 26 extencling outwardly o.E
one oE window ape.rtures 102, 104, 106~ IE, for t~xample, as depicted in Figure 12, a single cuttincl line passes out-wardly of the periphery of head 80 via aper-ture 102, the mass of the peripherally extending portion of -the line 26 will unbalance the head 80 in a rota-tional sense. Thus, the head at poin-t 102 will include a mass that is nvt ofEse-t by a corresponding mass at a location diame-trically opposite poi.nt 102. To overcome this deficiency, and with reference to Figure 13, there will be seen three balancinq ribs 102A, 104A, and 106A. Each balancing rib is located di.ametrically opposite its corresponding window aper-ture. Thus, for example, balancing rib 104~ balances window aperture 104. ~1hen the head 80 is assembled for grass cut-ting operation-and includes therein a full spool of line 26, the line is insertecl into one of aper-tures 102, 104, 106. The line extends outwardly of one of these aper-tures and acts as a flail to c~ut vege-tation. Normally, a five to six inch length of line 26 is _-- I

3~3~3 used for cutting operations. ~lowever, as noted above, it is this section of line that causes head 80 to rotate in an otherwise unbalanced condition. It is therefore the function of the balanciny ribs to offset this mass of the ~ive or six inch flail. This is accomplished by construc-ting the balancing ribs of an amount of material equAl in weight to -the mass of the ex-tended flail section of line member 26. This weight of the balancing rih will vary from uni-t to uni-t depending, of course, upon vaxiable Eackors `~
such as line diameter, line density, length of the flail portion o~ -the linc, and the particular materials o~ con-struction of khe head 80, cutting line 26, ancl balallcing ribs 102A, lO~A, and 106A~ Su~ficierlt to say, howevcr, that the balancing ribs have a mass equal or substantially equal to the mass of the extended cu-tting flail portion of line 26.

The curvilinear line bearing surface 61 and 61A
of each of window apertures 102, 104, 106, is preferably ~-formed by constructing tlle head membe~ 30 of a pair of spaced-apart walls 200 ancl 202 as seen in Figures 12 ancl 13. Thus, wall 200 defines the outer periphery of head member 80, whereas wall 202 defines the inner periphery thereof. It will be seen that in Figure 13, the balancing ribs 102A, lO~A, and 106A, are placed between walls 200 and 202 and are posi-tioned radially with respect to the axis of rotation of the head or housing member 80. As illustrateci in Fi~ure 13, the space between walls 200 and 202 is o-therwise open.
It should be noted, that the two exit head embodiment of Figures 7 and 8 is likewise of double-wallecl construction as hereinbefore explained with reference to ~igures 12 and 13.

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~ 3~'~3 Referriny now to Ficjures 18 - 20, and more par-ticularly to Fiyure 18, there is therein depicted an embodi-men-t oE the present invention featurinc; a manually operated JcniEe assembly or cu-tting mechanism 7 which functions -to cut the line member 26 to approximately the desired lengtil prior to the startup of a vegetation cutting operation. Thus, -the knife assembly 7 is attached and carried by housing 8 and is located -thereoll at a position above -the head member 42 and vertically spaced above the cutting plane. The knife assembly is positioned a predeterminecl distance above the cut-ting plane so that operation of the kniEe 7 to pre-cut line 26 results in a :Line length oE approYimately S-G inches.
Thus, the funct:ion oE kniEe assembly 7 is to enable the operator -to cut the line 26 to approximately its desired effec-tive cutting length prior to the grass cutting opera-tion. The line 26 will be cut to the exact lengtll desired by the automatic knife assembly 37 during actual operation of the device, which will be described hereinafter witl reference -to Figures 21 and 22.

l~eferring now to Figure 20, the knife assembly 7 will be seen to comprise a pair of spaced-apar-t and para-llel mounting flanges 23 and 24, fixed to housing 8 or molded integrally -therewi-th. Pivotally mounted within flanges 23 and 24 is a movable pressure block 29 carried by pins 41 and g3. ~s seen in Figures 18 and 19, the pins ~1 and 43 provide for pivoted movement of the pressure blocJc 29 towards and away from housing 8. Thus, in Figure 18, the pressure block 29 is moved away from housing 8 to receive the section 2~ of the line rnember to be cut, while in ~igure ]9, the pressure block 29 is shown in it position after the cutting of line 26 to a predetermined length has been completed.

~ s seen in Figure 18, housing 8 carries a station-ary knife blade 45 which is preferably of metal of riqid construction and includes a durable and sharp cutting surface. ~lousing'8 includes a beaded slot 47 for mounting the blade 45, with slot 47 being constructed sucl-that blade 45 may be removed therefrom for purposes of re-placing therein a fresh blade element. Thus, blade 45 will become dulled over a period of use and beaded slot 47 pro-vides for the ready replacement thereof.

ReferrincJ again to Figure 20, pressure block 29includes an aperture 49 tilerein, and a force plate me~ e~
51. When it is desired to -trim line 26 to a pretletermillecl length prior to beginning a vegetation cutting operation with the device of the present invention, the terminal enc]
of line member 26 is brouyht upwardly towards assembly 7 and inserted into and through àperture 49. This places the line member 26 between the blade 45 ancl the force plate 51.
~djustment of the amount of line pulled upwardly through aperture 49 will obviously determine the lerlgth wllich will be trimmed off and hence the length of line 26 remainincJ
after the line trimming operation. Once positiolled as above between blade 45 and force plate 51, it is simply necessary to manually push pressure block 29 towards ho~sing 8. Ilence, force plate 51 forces line 26 against blade 45 and tlle line is tllereby cut as seell, for éxample in Figure 19, with thc ' free cut end portion 26~ falling to the ground. 'I'lle pre-cut section of line 26B is then removed from cuttincJ assembly 7 with the result that the unit may then be used to cut vec~e-tatioll in -the fashion hcreinbefore described. ~or th~e sake ... .
2~
. ~ .

of convenience, the pressure block 29 may be provided wi.th a slanted lower wall 53 to easily accommodate grasplng there-of by a thumb and forefinger, for example, in order to lift the block 29 away Erom the housiny 8. It will therefore be apparent that assembly 7, as above described, provides a convenient mechanism for the operator of the device of the present invention to pre-trim the line 26 to size, and elim-inates the necessity of the operator oE the device to carry upon his person some type of knife or cutting mechanism.

~i-th reference now to Figures 21 and 22, there is therein illus-trated and depicted a stati.onary and auto~
matic CUttill~ assembly 37 for trlmminy line 26 to size as the head member ~2 rotates. Thus, as shown i.n Fiyure 22, lnterfercnce shield member 30 carries at its underside cut-tiny blade or knife element 71 having a sllarp metal cutting surface 71A. Carriecl integrally wi-th member 30, is a knife mounting assembly indicated by the numerals 81, 81B and 9l.
The mountiny assembly for the knife 71 includes and is seen to comprise, a sinyle downwardly extendiny and solid wall section 81~ haviny an upper bead portion 91 and a lower bead por-ti.on 81. ~ach of the beads includes therein slots 81A and 91A for removably receiving the blade 71. Thus, it will be apparent that when blade 71 becomes dulled after extended use, i-t may be easily replaced with a fresh blade by first removing the blade 71 from mounti.ny wall section 81B, by slidiny blade 71 out from slots ilA ancl ~lA. '~'he new blade is then inserted in slo-ts 81~ and 91A and pushed alony the slots until the surface 71~ is in aliynment wi.th ~ the outer edges of beads 81 and 91 as is clearly depic~ed .in Fiyure 22. It should be noted that the blade 71 is ~ 3~3~3 supported ~nd braced all along its rearward surface by wall portion 81B, only a portion of which is shown exposed in Flgure 22.

It wil] be .readily apparent, -there:fore, with the knife 71 moun-ted as described above, that the cuttiny su.rface 71A lies in a plane perpendicular to the path o~ travel of the line member 26. Thus, as seen in Figure 21, tlle line 26 is rotated by head member 42 in a path which must cross the ~.
blade suxface 71~. As line member 26 is so rotated, it is automatically trimmed to its desired length 26B with the excess portion 26~ :Ea].ling by ~he wayside. I.E it is desired to cut vegetation with a line 26B of a length oE 5.0 inches for example, it i.s simply necessary in the construction of this unit -to space knife 71 five inches from the outer periphery of the head member ~2. Thereafter, a five inch line length 26B will be maintained automatically and regard-less of the fact -tha-t the line member is six inches in :
length prior to start-up of the apparatus. It is tllerefore ~ con-templated, tha-t the opera-tor o:E the device will initially pay out abou-t seven or eight inches of line 26 from llecld member ~2 prior to -the initia-tion of any vegetation cutting operation. The operator may then pre-cut the line 26 to about six inches with the knife assembly depicted in Figures 18 - 20. Thereupon r and af-terwards, the blade assembly 37 ~ .
of Figures 21 and 22 will automatically cut the line 26 to the exac-t length 26B desired, which according toithe preferred mode of operation disclosed herein is about 5.3 inches.

Hence, it will be seen that the dual knife assembly of Figures 18 - 22 provides a simple and convenient system for cutting the line member 26 to its desired and e~Eecti.ve work-3&~3 ing length and without the necessity of manually measuringthe length thereof.
In a preferred embodiment of the present inven-tion, it has been determined that an effective length-to diameter ratio for a nylo,n monofilament line 26 or the like, will o~ten be about 35:1 and may be as high as about 82.1 for present purposes. It has further been found that the best cutting line for the purposes of this invention are extruded nylon line, having a diameter of about 0.060 inches to about 0.125 inches, with 0.065 to 0.080 inches being pre-ferred. The normal rotating speed will be on the order of 6000-7500 RPM, with 6800-7000 RPM being preEerably during normal use of the equipment of Fiyure 1.

Referring now to the embodiment of Figure 23, a port-able type edging and trimming device generally designated by the numeral 2 is shown, and which is of the type preferred for lighter tasks in residential-size plots or areas, and -the like, where electrical power is immediately and convenien-tly available to the operator. Accordingly, the apparatus may be composed of a !
,, , 3~3~3 tubular member 4 having a casing 8 eontaining electric motor 10 mounted at one end, which motor clrives a string eutting head 42. The tubular member 4 is removably a-t-taehed -to and supports easing 8 by screws 15 insertable in shank 14. Sueh a deviee 2 is portable and ls hand held and manipulated by an operator by means of trigger handle 16. Handle 16 is fixedly attaehed to the tubular member 4 by means of serews,indieated generally at 25. Power may be applied to -the motor 10 through a eonventional eleetrieal-type insulated eord or eonductor 20, having an appropriate plug at one end (no-t shown), and having its other end passed through the tubular mer,lber 4 for con-neetioll with the motor 10 by means oE eonneetor 17. An appro~
priate ON-OFF switch or trlgger 22 ma~ conveniently be located adjacent the han~le 16 at the upper end of the tubular member 4, for intereonnection wi-th the eonduetor 20 and motor 10. The eutting plane of the eutting string 26 may be easily arranqed in either a horizontal or ver-tical position or til-ted to any angle, to eut along sidewalks, around trees and rocks, and alony fences and the like, where it is either unsafe or difficult to cut with conventional appara-tus, merely by -turning and manipu-lating handle 16. Referring more particularly to Figure 23, there may be seen a hollow casing 8 or the like, with a single string circular cu-tting head 42 which is ro-tated by shaft 36 of eleetrieal motor 10 of suitable design mounted within casing 8.
The eu-tting head 42 may be further seen -to include cutting strand 26 extending laterally from the cu-tting head 42 through either aperture 60 or 62 (Figure 25) of suitable configuration, a distance whieh is a func-tion of the present invention as will ; hereinafter be explained. As further indicated, the casing may have a flange portion or shield 30 for preventinc3 the cutting head 42 from being brought in-to injurious contact with a wall or tree during its rotation by motor 10.
Referring now to Figure 26, it may be seen that the lower end of the ~rive shaE-t 36 from motor 10 is arranged for threading engagemen-t with a drive adapter or attachmen-t mem-ber 36A. Drive adapter 36A extencls downwardly through head 4 2 and is arranged at its upper extremity for threading arrange-ment with shaft 36. Drive adapter 36A inser-ts tightly into head 42 and retains its relationship with head 42 by means of head 40 which is carried within head 42. Rota-tion of drive adapter 36A by drive shaft 36 causes heacl 42 to rotate, thereby extend-ing the striny 26 to perforrn a cuttiny function.
Tab element 32, in additioll to housing drive adapter 36A and securing said drive adapter 36A in relationship with head 42 so as to provide axial rotation thereof, also releasably secures spool 44 within head 42 as shown in Figure 27. Spool 44 contains spare cuttin~ line 46 therein, which is arranged for paying out at predetermined times and at predeter-mined lengths to vary the effective working length of the cutting line 26. Unlocking of tab elernent 32 by unthreading it from lcey-way slots 21 allows removal of spool 44 so tha-t a fresh full spool may be inserted into head 42, or spool 44 may be rewound with replacement line, or the like.
Spool 44 as seen in Figures 27-31 is composed of a bottom wall 48 and a top wall 50 spaced a predetermined distance by hub 52. Interior of hub 52 is an aperture 54 which accommodates keyway elements 21 to fit over tab elemen-t 32 and lock spool 44 to head 42 when the spooL 44 is placed within head 42. Thus, it will be apparent from Figure 27, that tab element 32 includes a pair of ears 32A and 32Bb Each of ears 32A and 32B are spaced ~3 5a 3 ~ 4 3 above the wall 19 of head 42. Spool member 44 includes keyway elemen-ts 21 and 21A each of which is carried by the hub 52 of the spool 44 and formed integrally therewith. Each keyway will be see.l to comprise a pair of inwardly extend.ing flange elements 64 and 66 which define therebetween an open ended slot 68. It should be apparent that when spool 44 is inserted into head member 42, that the slot 68 will be positioned to encompass one of ears 32A-B. ~s seen in Figure 28, the top wall 50 of spool 44 includes a radially extending member 56 which may be ~ ;
grasped manually by the thumb and forefinger. Turning of mem--ber 56 ttlereby rotates the spool 44 Witilill head rnember 42 so as to cause the slot.~ 68 oE }ceyways 21 and 21A to engaye and thereby lock witll respect to each of the ears 32A-B of tab ele-ment 32. This provision of tab 32 and keyways 21 and 21A pro-vides an easy and convenient manner by which spool 44 may be placed within and locked for rotation along with head member 42. ~ ~;
To remove tlle spool 44 from head member 42, it is merely required to turn member 56 in the opposite direction whereby slots 63 of the keyways are unlocked from the respective ears of the tab member 32.

,, 3~

Referring now to Figures 25-27 the two window aper-tures 60 and 62 are each composed of a pair o:E curvilinear and spaced apart solid sidewalls 61 and 61A. In this embodiment of the present invention, the cutting line 26 is composed of a coiled portion 46 (Figure 26) wound about the spool 44,-and a ~ree travelling end portion extending along a tangent thereto outwardly through one of the respective window apertures 60 and 62. Accordingly, the line tends to abut the trailing one of the pair of sidewalls 61 and 61A composing -the respec-tive one of the two windows 60 and 62, ra-ther -than the sidewall which leads the llne as it is carried arcuately about by rota-tion of the cutting head 42.
The cutting line 26 tends to vibrate longitudinally as the cutting head 42 is rotated, and thus to oscillate laterally against the trailing sidewall of one of the windows 60 and 62 in a manner to generate sufficient localized heat to at least partially melt the cutting line a-t a poin-t along its length where it contacts the said trailing sidewall. The tear-drop portions 74 and 74A minimize such rubbing to some extent 2~ by tending to hold the line immobile a-t these points, but SUC}l holding effort as may be exerted by the tear-drop portions 74 and 74A must of necessity.be limited so as not to restric-t the ease whereby new lengths of the cutting line may be paid ou-t as desired.
It has been found beneficial, therefore, to pro-vide these trailing sidewalls with metallic bearing element .~ .

3~

inserts 76 and 78 preferably formed of a unitary piece of mate-rial which has a reduced tendency to develop friction from engacJement wi-th the vibrating cutting line, and further pre-ferably having a smooth or polished surface for carrying the cutting line. These inserts 76 and 78 may be formed in one piece of a variety of different ma-terials which are suitable for such purposes, but it has been found that a polished metal such as brass or stainless steel is especially suitable. The bearing element will be seen to include an apertured wall 58 connecting inserts 76 and 78. The aperture 5~A is sized -to pass over -tab elernent 32 and resk flush with wall 19 of head element 42 so as not to interfere with the locl~ing mechanis 21 and 21A.
With refe]ence again to Figure 27, a further feature of -the present invent:.on includes means whereby the head may be balanced rotationally so as to no-t transmit unwan-ted vibra-tions to the motor shaft 36. Thus, to provide a smooth running and rota-tionally balancecl head assembly 42, it is necessary to offset the weight a~tributable to the line 26 extending out-wardly of one of window apertures 60 and 62. If, for example, as depicted in Figure 26, a single cutting line passes outwardly of the periphery of head 42 via aperture 62, the mass of the peripherally extending portion of the line 26 will unbalance the head 42 in a rotational sense. Thus, the head at point 62 will include a mass that is not offset by a corresponcling mass at a location diarnetrically opposi-te point 62. To overcome this deficiency, and with reference to Figure 27, there will be seen guard 70 with cut-out 72. When the head 42 is assembled for grass cutting operation and includes therein a full spool of line 26, the line is inserted into one of apertures 60 and 62.

3~'~3 The line extends ou-twardly of one of these apertures and acts as a flail to cut vegetation. Normally, a three inch length of line 26 is used for cu-tting operations. However, as noted above, it is this -three inch section of line that causes head 42 to rotate in an unbala~ced condition. It is therefore the function of the cut-out 72 to offset -this mass of the three inch flail. This is accomplished by constructing the cut-ou-t portlon 72 to be of an amount of material equal in weight to the mass of the extended three inch flail section of line mem-ber 26. This weight of -the rernoved cut-out portion 72 will vary from unit to unit depending, o course, upon variable factors such as line diameter, line density, length of the flail portion of the line, ancl the particular materials of con-struction of the head 42, cutting line 26, and guard member 70.
Sufficient to say, however, that the guard 70 includes a cut out 72 of a mass equal or substantially equal to the mass of the extended cutting flail portion of line 26.
In the Figures 23-32 embodiment of the present in-vention, it has been determined -that an effective length-to-diameter ratio for a nylon monofilamen-t line or the like, will often be greater than 20:1 and is preferably about 35:1 for present purposes. It has further been found -that the best cutting line for the purposes of this invention are extruded nylon line, having a diameter of about 0.060 inches to about 0.125 inches, with 0.065 inches being preferred. The normal rotating speed will be on the order of lO,000 - l~,000 RP~, with 12,000 RP1~ being preferable during normal use of the equip-; ment. It has been determined further that ~or this Figure 23 3~ embodiment disclosed herein, -the optimum parameters call for a cutting length of about 2.3 inches being preferred. A
.~

~. I

3&~'~3 head diameter of about 3.4 inches is desirable, thus providing a cutting path of about 8.0 inches, although cutting heads of substantially larger or smaller diameters are contemplated herein.
Referring now to the embodiment of Figure 33, a portable type mowing and edging device generally designated by the numeral 2 is shown, and which is of the type preferred for lighter tasks in residential-size plots or areas, and the like, where electrical power is immediately and conveniently avail-able to the operator. Accordingly, the apparatus may be com-posed o a tubular member 4 having a casing 8 con-taining elec-tric motor 10 mounted at one end, which motor drives a stringcutting head 42. The tubular mernber ~ is removably attached to and su~ports casincJ 8 by screws 15 inser-table in shank 14.
Such a device 2 is portable and is hand held and manipulated by an operator by means of trigger handle 16 and intermediate handle 18. Handle 16 is attached to tubular member 4 by screws 25, whereas handle 18 is attached to tubular member 4 by an easily adjustable wing-nut assembly 27. Power may be applied to the motor 10 through a conventional elec-trical-type insulated cord or conductor 20, having an appropriate plug at one end (not shown), and having i-ts other end passed through the tubular member 4 for connection with the motor 10. An :
appropriate ON-OFF switch or trigger 22 may conveniently be located adjacent the handle 16 at the upper end of the tubular ~.
member 4, for interconnection with the conductor 20 and motor 10. The cu-tting plane of the cutting striny 26 may be easily arranged in either a horizon-tal or vertical position or tilted to any angle, to cut along sidewalks, around trees and rocks, and along fences and the like, where it is either unsafe - 3~ -.

3~3 or difficult to cut witll conventional ~pparatus, merely by turning and manipulating handles 16 and 18.
The single string circular cutti.ng head 42 is rotated by the shaft 36 of the electrical motor 10 mounted within casing 8. The cutting head may further be seen to include cut- ~.
ting strand 26 extending laterally from the cutting head 42 through either aperture 60 or 62 (Figure 34) of the suitable configuration, a distance which is a function of the present invention as will hereinaf-ter be explained. ~s further indi-cated the casing may have a circular flange portion or inter-ference member 30 for preventing the cutting head 42 from be.ing brought into injurious contact with a wall or tree cluring i.-ts rotation by motor 10. Shield member 30 may have a cut-ting blade 21 suspended therefrom perpendicular to the cutting pa-th by means of holder 23 at the extremity of shield 30 furthest from head 42. Cutting blade 21 acts as a line length adjuster by automatically trimming off excess line lengths when the head 42 is rotated sufficiently rapidly to cause string 26 to stand out rigidly from the cutting head ~2 and pass across -the cutting blade 21. An additional line trimming blade 23~ is located on the outside front portion of casing 8 and includes a hinged line trimmer lever 25. This trimming blade 23A may be used to trim line for any reason while the device 2 is not in operation.
In the Figure 33 embodiment of the present invention, it has been de-termined that an effective lenqth-to-diametex ratio for a nylon monofilament line or the like, will often be greater than 40:1 and is preferably about 49:1 for present purposes.
It has further been found that the best cutting line for the pur-poses of this embodiment are extruded nylon line, having a diameter of about 0.060 inches to about 0.125 inches, with 0.065 inches being preferred. ~he normal rotating speed w~ll be on the order of 6000 ~ 10,000 RPM, with 8,500 ~PM being preferable ,; I

~3~f~3 during normal use.
Referring now.to Figures 33-42, it may be seen that the lower end of the drive shaft 36 extends downwardly through head 42 from motor 10 and is arranged for threading engagement at i-ts lower end 35 with keyed retainer member 37 in threaded aperture 39. Drive shaft 36 inser-ts tightly into aperture 39 in head 42 and retains its relationship with head 42 by means of its flattened portion 31, which is :insertable into head 42. Rotation of drive sha:Et 36 by motor 10 causes head 42 to also ro-tate, thereby extending the string to per-form a cu-tting function.
Spool 44 contains spare cutting line 46 therein, which is arranged for paying out at predetermined -times and at predetermined lengths to vary the effective workiny length of the cutting line 26. Spool 44 is composed of a bottom wall 43 and a top wal]. 50 spaced a predetermined e~uidis-tance by hub 52. Interior and on the top sicle of hub 52 is a centrally located opening 57 wherein two annular locking protuberances 49 and 51 spaced diametrically opposite each o-ther and extend-i.ng partly around the interior of spool 44 are arranged for releasable engagement with protuberances 43 and 45 on retainer member 37. Removal of spool 44 from head 42 may be accomplished by rotating spool 44 by means of grip element 33 so that lock-ing protuberances 49 and 51 are rotated ou-t of l~cking engage-ment with protuberances 43 and 45 on retainer member 37.
Removal of spool 44 from head 42 enables a fresh spool to be inserted into head 42, or spool 44 may be rewound with replace-ment line or the like.
' :.

Window insert member 76, composed of arms 76A and 76B and inserts 77A and 77B, is releasably retai.ned w.ithin head 42 by re-tainer member 37 which is insertable through aperture 79. Inserts 77A and 77B correspond to and insert into window apertures 60 and 62 in head 42, and enhance cut-tiny line life.
As previously described, head 42 is rotated by shaft 36 of motor 10 inserted into aperture 39 of head 42.
The spool 44 with cutting line 26 wound -thereon is contained within head 42 between two semicircular housing walls 41A and 41B, each having inner walls 202 and outer walls 200. q'he head 42 is provided with two window apertures 60 and 62 where-from a cutting string may protrude, the said two apertures each having a curvilinear bearing surface 61.
Referring now to Figures 43-49, an alternate embodi-ment of the present invention is shown, similar to that depicted in Figures 34-42. As hereinbefore described with regard to head 42, the single string circular cutting head 142 is rotated by the shaft 136 of mo-tor 10. The lower end of drive shaft 136 20 is arranged for threading engagement with re-tainer member 137 in aperture 135. Drive shaft 136 inserts tigh-tly into aperture 131A and in head 142 and retains its relationship with head 142 by means of its flattened portion 131, as hereinbefore dis-cussed.
Spool 144, similar to spool 44 in Figure 3~, con-tains spare cutting line 146 therein which is inserted into aperture 155 and wound onto and payed out from hub 152 as hereinbefore described in detailO Spool 144 also has a bottom wall 14 8 and top wall 150. Hub 152 extends beyond bottom wall 14~ to form glide ball 133. Interior of hub 152 is a centrally ~ 3~

located cavity 157 wherein three annular locking protuberances 151A, 151B, and 151C, equally spaced about the circumference of cavi-ty 157, are arranged for releasable engagement wi-th pro-tuberances 149A, 149B, and 149C within head 142. Removal of spool 144 ~rom head 142 may be accomplished by rotating spool 144 by means of glide ball 133, the ex-ternal surface of which may be provided with equally spaced-apart vertical lineal pro-trusions 132 to insure a better grip for easier removal, so that locking protuberances 151Al 151s, and 151C are rota-ted out of loc~ing engagement with pro-tuberances 149A, 149B and 149C within head 142.
Window insert member 176, composed of arms 176A, 176B and 176C and inserts 177A, 177B and 177C, is releasably retailled within head 142 by spool 144~ Aperture 179 perrnits retainer member 137 to pass therethrough and engage drive shaft 136. Inserts 177A, 177B and 177C correspond to and insert into window apertures 160, 162 and 164 in head 142, and enhance cutting line life as has previously been explained in detail.
Head 142 is siMilar -to head 42 previously depicted and described. The spool 144 with cutting line 146 wound thereon is con-tained within head 142 be-tween three semicircular housing walls 141A, 141B and 141C, each having inner walls 202 and outer walls 200. The head 142 is provided with three window apertures 160, 162 and 164 wherefrom a cutting string may protrude, the said three apertures each having a curvi-linear bearing surface 161.
With reference to Figures 44 and 45, a further feature of the present invention includes means whereby -the three exit head embodimen-t may be balanced rota-tionally so as to not transmit unwanted vibra-tions to the mo-tor shaft 136.

~ 38 ~

~3~ L3 ~o overcome this defic.iency, and with reference to Figure 46, there will be seen three balancing ribs 160A, 162A, 164A.
Each balancing rib is located diametrically opposite its cor-responding window aperture. Thus,,for example, balancing rib 164A balances window aperture 164..
As he.reinbefore noted, the curvilinear line bear-ing surface 161 of each of window apertures 160, 162, 164, is preferably formed by constructing the head member 142 of a pair of spaced apart walls 200'and 202'seen in Figures 44 and 45. Thus, wall 200 defines the outer periphery of head member 142 whereas wall 202 defines' the inner periphery thereof.
It will be seen that in Figure 44, the balancing ribs 160A, 162A and 164A, are placed between walls.200'and;202 and are positioned radially with respect.to the axis of rotation of the head or housing member 142. As illustrated i.n Figure 44, the space between w~lls 20~ and 202 is o-therwise open. It should be noted, that the two ex'it:head embodiment of Figures 35 and 36 is likewise of doubIe-walled construction as herein~
before explained with reference to Figures 44 and 45.

Claims (7)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for cutting vegetation and the like, comprising:
head means rotatable about a rotational axis in a cutting plane and having a concentrically located open-end storage portion for a spool means and a peripherally located support portion having a solid curvilinear bearing surface, driving means for rotating said head means in said cutting plane, a flexible non-metallic line member having a coiled portion in said storage portion of said head means and further having an uncoiled portion extending from said coiled portion into said cutting plane to and across said bearing surface and further continuing radially outwardly from the periphery of said head means, spool means insertable in said storage portion of said head means through the open end and holding said coiled portion of said line member in said head means, and tab means and a keyway associated with said head means and spool means and adapted to be axially interfitted and rotationally interlocked whereby an axially and radially secure interconnection is provided between said spool means and head means.

2. The apparatus described in Claim 1, including a guard member in surrounding relationship to said spool means said guard member including an aperture therein through which said line member passes.

3. The apparatus described in Claim 1 wherein the tab means are integrally united to said head means.

4. The apparatus as described in Claim 3, wherein said curvilinear bearing surfaces of said head means include teardrop-shaped sections extending outwardly with respect to the periphery of said head means.

5. Apparatus for cutting vegetation and the like, comprising:
disc-like means rotatable about a rotational axis in a cutting plane and having a concentrically located open-ended storage portion for spool means and a peripherally located support portion having curvilinear bearing surfaces defining one or more peripheral apertures, driving means for rotating said head means in said cutting plane, a flexible non-metallic line member having a coiled portion in said storage portion of said head means and further having an uncoiled portion extending from said coiled portion into said cutting plane to and through at least one of said peripheral apertures and further continuing radially outward from the periphery of said head means, circular spool means insertable axially against an abutment surface in said storage portion of said head means through the open end and holding said coiled portion of said cutting line, said spool means including first tab means associated therewith, second tab means on said head means in said storage portion and cooperating in angular interfitting with said first tab means to lock said spool means in said storage portion of said head means, metallic bearing elements including portions in abut-ting relationship to the curvilinear bearing surfaces of each of said peripheral apertures, central guide means on said spool means and head means for positioning said spool means coaxially in said head means and with said first tab means in angular alignment with said second tab means, said spool means rotated in one direction a partial turn about the rotational axis relative to said head means to interfit said second tab means and said first tab means whereby said spool means is locked within said head means against un-intended axial and radial displacements but reverse rotation of said spool means over the partial turn releases said spool means for ready axial removal from said head means.

6. The apparatus of Claim 5, wherein one face of said head means includes a glide ball member integrally carried by said spool means, said glide ball member having a convex surface adapted to contact the vegetation when said apparatus is moved therealong.

7. The apparatus of Claim 5, wherein said spool means has a central tubular hub carrying spaced apart planar flanges with circular peripheries, said hub at a first end carrying a circular ridge forming an abutment surface, and at a second end thereof, integrally carrying a glide ball member having a convex surface adapted to contact the vegetation when said apparatus is moved therealong, and said first tab means positioned on said central tubular hub adjacent said first end thereof.