GB1582568A

GB1582568A - Filament wound plate for filament cutter

Info

Publication number: GB1582568A
Application number: GB28493/77A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-07-07
Filing date: 1977-07-07
Publication date: 1981-01-14
Also published as: DE2731058A1; DE2731058C2

Description

(54) FILAMENT WOUND PLATE FOR FILAMENT CUTTER (71) I, CHARLES BERNARD PITTINGER JR., of 320 Cockeys Mill Road, Reisterstown, State of Maryland, United States of America, a citizen of the United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates generally to filament cutters for cutting grass and the like.

Structure previously disclosed by me for the purpose includes a disk or plate with a circular series of perforations through which the filament is threaded in a predetermined serial mode.

An object of the present invention is to provide for faster mounting of filament in disk structure.

According to the present invention there is provided an assembly for cutting grass and the like, including an operationally rotatable disk having a series of apertures circumferentially therearound with a length of filament fixed to the disk and having a terminal length thereof extending from one of said apertures as a cutting length of the filament, with a plurality of the apertures engaging successive intermediate portions of the filament at intervals providing for each said successive intermediate portion of the filament in turn to become a said terminal length thereof extending as a cutting length on parting of a previous said terminal length thereof during operational rotation of said disk, said apertures being in communication radially with the outside of the disk during assembly whereby the filament can enter said apertures from a position radially exterior of the disk, and means for preventing the filament from escaping radially outwardly from said apertures on operational rotation of the disk, said means being effective after the filament has entered some or all of said apertures during assembly.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figures la, ib and ic are respectively a top plan, a side elevation and a radial section, showing fragmentary details of a first embodiment of the invention; Figures 2 and 3 are top plan fragmentary details of a second and third embodiment; Figures 4a and 4b are top plan fragmentary details of a fourth embodiment and a variation thereon; Figures 5a and 5b are respectively a top plan view of a fifth embodiment and a top plan fragmentary detail thereof at a later stage of manufacture; Figure 6 is a top plan view of a fragment of a sixth embodiment; Figure 7 is a top plan view of a fragment of a seventh embodiment; Figures 8a and 8b are respectively an exploded view and a view assembled of an eighth embody.

ment; and Figures 9a and 9b are respectively an isometric fragmentary detail during assembly and a side elevation in section after assembly of a ninth embodiment.

Figures la, ib and lc illustrate an embodiment 10, showing rim of a disk or plate 16 which has a plurality of apertures 18 or filament wind-over areas around the periphery, and a slot or opening 20 passing outward from the aperture through the periphery. An element movable to close the slot is provided as follows.

A portion of the material, which may be mild steel, forms a bent tab 22 bounding the slot on one side. After an intermediate portion of the filament 24 is wound into the aperture or passes radially into the aperture, the tab is bent into the plane of the disk, effectively closing the aperture as at 22', forming a smooth periphery and preventing the terminal length of the filament 24', if adjacent, from escaping radially out of the aperture on rotation of the disk about the center 26, when the terminal length will swing beyond the periphery as a cutting length. When wear and stress eventually part the filament at the aperture, a new terminal length 24" swings outward as a cutting length from another aperture 18' in accordance with principles set out in U.K. Patent No. 1506608.

Figure 2 illustrates an embodiment 200 having a self-sealing slit 220 through the periphery into the aperture 218. Material of the disk 216 is chosen to be sufficiently resilient to pass the filament 224, shown in section, under winding pressure, resealing behind it.

Polypropylene or other resilient material can be used for the purpose, and the slit can be heat sealed or welded after winding, if desired.

The filament is therefore prevented from escaping by the structure defining the slit.

Figure 3 shows an embodiment 300 similar to the preceding Figure except that the slit widens outwardly at the periphery of the disk, facilitating passing the filament into the aperture through the recess 326.

Figure 4a illustrates an embodiment 400 with a fixed-width slot 420 through the periphery of the disk 416 connecting with the aperture 418. Resiliently deformable filaments such as "Nylon" monofilament can be stretched or otherwise resiliently deformed to reduce the cross-section locally as at 424a, received in and passed through the slot which is made to be too narrow for the unstressed filament to pass, and then, when in the aperture, relaxed, so that the filament is prevented from escaping outward through the slot by the restoration of full diameter as at 424. The structure defining the slot therefore serves to prevent escape of the filament.

Figure 4h indicates that disk structure 416 similar to that of the preceding Figure can be bent in-plane at 422 to close the slot if desired, regardless of whether the slot is initially larger or smaller than the filament 424, and regardless of filament characteristics. Circularity of the aperture (preferred embodiments) contributes to low-stress in-plane bending of the disk structure.

In all the above embodiments, the opening through the periphery communicating with the aperture is preferably at an angle to a radius therethrough and tangential to the aperture. If the disk has a preferred direction of rotation (arrows) then the outward inclination of the opening is preferably in the direction of the preferred direction of rotation. These arrangements provide double assurance that the filament will be smoothly and positively retained under the variables of operation, since the filament is never aligned with the opening, but instead swings radially outward, or slightly behind the radial position, because of cutting resistance and air resistance. In either case the filament lies over a solid portion of the disk.

Figure 5a illustrates a starfish-like disk structure 516 in a preliminary stage of manufacture. Lach of the arms 522 has a lateral relief 528 corresponding to that of the other arms outward of the apertures, as part of the opening 520 between the ar's. Material is preferably mild steel. Function of the arms is shown in the next Figure.

Figure Sb indicates how the anus 522 of the preceding Figure can be inwardly bent or folded over themselves, toward the plane of the disk and laterally, overlapping and closing adjacent opening, with the contour of the relief 528 complementing said aperture by forming a continuation of the contour of the proximate aperture 518 enclosing the filament 524.

Figure 6 illustrates an embodiment 600 somewhat similar to that of the previous Figure, but with the arm ends 622 being movable elements folded over a ring 630, holding the ring concentric with the disk center, and capturing the filament 624 in the apertures 618. The ring may also be held in place by welding. A ring on each side of the disk may also be supplied.

Figure 7 illustrates an embodiment 700 with a ring 730 having recesses 720 in the inner circumference corresponding to the disk apertures 718 so that they together form closed contoured apertures. The ring and the disk may be welded or cemented to unite the ring with the circumference of the disk, which it fits, as at 717.

Figure 8 illustrates an embodiment 800 in which the disk 816 has a serrated periphery on which the filament is wound. The teeth 822 are formed by inclined recesses 820 through the periphery connecting with the apertures 818.

Following winding, a matching movable element 816', which may be an identical disk reversed and coaxially mounted so that the teeth 822' incline in the opposite direction, is moved relative to the disk, such as by relative rotation, so that the teeth close the openings outwardly of the apertures.

Figure 8b shows the finished result. Restringing or rewinding is easily accomplished by loosening the shaft nut, clamp, or any other common fastening device 832 which may be employed to hold the relative position of the parts, and rewinding the disk, following which the co-acting element is again assembled.

Size of the apertures is adjustable for various size filaments to an extent depending on to what degree the coaxial parts are rotated relative to each other.

Figures 9a and 9b show an embodiment 900 similar to that of the preceding Figure, in which identical disks have apertures surrounded by pressed or cast integral hemitoroidal structure 934 through which openings 920 through the periphery pass at an angle to radii passing therethrough. The openings may be radial to the apertures (but not to the disks 916) as shown. In any case the openings are narrow relative to the diameters of the apertures and the openings between apertures so that when the plates are placed face-to-face, filaments cannot be strung because they cannot pass through the openings which, being inclined to the disk radius, cannot be congruent even though the apertures are congruent. This requires axial separation of the disks for stringing or winding access to the apertures 918. The toroidal structure on assembly of the plates or disks form a continuously curved structure for the filament 924.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood thatwithinthe scope of the appended claims the invention may be practised otherwise than as specifically described.

Reference is made under Section 9 of the Patents Act 1949 to patent No. 1506608, already referred to above, Claim 1 of which reads: A member for a filament trimmer, the member having means for attaching it to a rotary drive, a filament, and further means on said member for supporting the filament at spaced locations thereon in such manner that the filament has a segment that extends outwardly of the member under centrifugal force upon rotation of the member to form a first cutting segment, said further means being operable, upon severance of the said first segment during rotation of the member, automatically to extend the filament outwardly of the member in such manner as to provide another segment that forms a second cutting segment.

Claims

WHAT I CLAIM IS:

1. An assembly for cutting grass and the like, including an operationally rotatable disk having a series of apertures circumferentially therearound with a length of filament fixed to the disk and having a terminal length thereof extending from one of said apertures as a cutting length of the filament, with a plurality of the apertures engaging successive intermediate portions of the filament at intervals providing for each said successive intermediate portion of the filament in turn to become a said terminal length thereof extending as a cutting length on parting of a previous said terminal length thereof during operational rotation of said disk, said apertures being in communication radially with the outside of the disk during assembly whereby the filament can enter said apertures from a position radially exterior of the disk, and means for preventing the filament from escaping radially outwardly from said apertures on operational rotation of the disk, said means being effective after the filament has entered some or all of said apertures during assembly.

2. An assembly as claimed in Claim 1, wherein the communication is effected by slits through the periphery of the disk connecting with said apertures, and the means for preventing escape comprise the structure defining the slit, which structure is resiliently yielding sufficiently for permitting passage of the filament through the slit and for closure thereafter.

3. An assembly as claimed in Claim 2, the slit widening outwardly toward the outer end thereof, forming a recess for facilitating engagement of the filament with the slit.

4. An assembly as claimed in Claim 1, wherein the communication is effected by slits each at an angle to a radius of the disk therethrough and connecting with a side of said aperture.

5. An assembly as claimed in Claim 2, 3 or 4, the disk having a preferred direction of operational rotation, and the slit angle outwardly inclining toward the preferred direction of operational rotation.

6. An assembly as claimed in Claim 1, said filament being resiliently deformable permitting reducing the cross section thereof by tensioning the filament, the communication is effected by slits through the periphery thereof connecting with the aperture, each slit being wider than a cross section of the filament when the filament is resiliently deformed by tensioning to reduce the cross section thereof while under said tension during entry thereof into said aperture, the means for preventing escape comprising the structure defining the slit.

7. An assembly as claimed in Claim 1, wherein the communication is effected by slits through the disk periphery connecting with the apertures, and the means for preventing escape comprise elements substantially filling said slits respectively.

8. An assembly as claimed in Claim 7, said elements being deformed portions of the disk.

9. An assembly as claimed in Claim 8, said elements being structure forming a side of said slits.

10. An assembly as claimed in Claim 8, wherein said elements lie in a deformed position having been bent from a non-deformed position in a direction toward the plane of the disk.

11. An assembly as claimed in Claim 9, wherein said elements lie in a deformed position having been bent from a non-deformed position within the plane of said disk.

12. An assembly as claimed in Claim 1 wherein the communication is effected by recesses at the disk periphery connecting with the apertures and the means for preventing escape comprise a circular member retained proximately around the periphery of the disk by bent-over portions of said disk at the periphery thereof located between the recesses.

13. An assembly as claimed in Claim 1, wherein the communication is effected by recesses at the disk periphery connecting with the apertures and means for preventing escape comprise a series of projections at the periphery of a further disk formed between a series of recesses at the periphery thereof, said disk-like member being rotatable in relation to said disk from an opened position to permit entry of the filament and a closed position to prevent eacape of the filament.

14. An assembly as claimed in Claim 13, wherein the recesses in the disk are each inclined relative to a radius of the disk passing therethrough, and recesses in the further disk are similarly but oppositely inclined.

15. An assembly as claimed in Claim 1, wherein the communication is effected by slots at the disk periphery connecting with the apertures, said slots being each inclined relative to a radius of the disk, and said means for preventing escape comprise a further disk in engagement with said disk having slots at the periphery thereof, said slots of the further disk being similarly but oppositely inclined.

16. An assembly as claimed in Claim 15, wherein the disk structure proximately around the disk aperture has a hemi-toroidal shape, and the further disk structure proximately around the movable element aperture has a complementary hemi-toroidal shape, thereby forming a continuously curved structure for the filament with all said apertures congruent.

17. An assembly as claimed in Claim 1, wherein the communication is effected by recesses at the periphery contigious with the apertures and the means for preventing escape comprise a circular member having recesses on the inner surface thereof, means being provided to secure said circular member in place.

18. An assembly as claimed in Claim 17, wherein the recesses of the circular member are complementary in shape and location to the apertures and the contigious recesses in said disk, forming therewith a closed contoured aperture.

19. An assembly as claimed in Claim 1, wherein the communication is effected by recesses at the disk periphery connecting with the apertures thus forming a star-fish like configuration having radial arms with recesses therein, and the means for preventing escape comprise bent over portions of said arms, said portions lying in a deformed position with the recesses in the arms complementing said apertures having been bent from a nondeformed position in a direction toward the plane of the disk.

20. A method of manufacturing a filament wound plate, comprising the steps: winding successive intermediate portions of a filament across a plurality of openings in the periphery of a plate, and causing the filament windings to be retained against passage from the openings in a direction radial to the plate after the filament is wound thereon.

21. An assembly as claimed in Claim 1, substantially as described with reference to the accompanying drawings.

22. A mowing machine having an assembly substantially as described herein with reference to the accompanying drawings.

23. A method as claimed in Claim 20, substantially as hereinbefore described.