DK167795B1

DK167795B1 - CUTTING BUTTON FOR CUTTING CUTS

Info

Publication number: DK167795B1
Application number: DK065189A
Authority: DK
Inventors: Helmut Weid
Original assignee: Wolf Geraete Gmbh
Priority date: 1988-02-18
Filing date: 1989-02-10
Publication date: 1993-12-20
Also published as: PT89756A; ES2022072T3; PT89756B; DK65189A; DE3805092A1; ATE69536T1; EP0328988A1; NO890697L; DE58900460D1; ES2022072A4; DE3805092C2; DE8808045U1; NO168223B; DK65189D0; NO168223C; EP0328988B1; NO890697D0

Abstract

In a two-armed cutter bar (10) for a lawnmower with a vertically rotating shaft, the cutters (14) are fastened at each of the two ends by means of a respective single fastening bolt (36). The end portions of the cutter bar (10) have conical rotary guides (24), into which fit correspondingly conical rotary guides (38) of the cutter carrier plates (32). This ensures centering and rotary guidance. A positive junction between a rib (46) of the cutter carrier plate (32) and a bead (20) of the cutter bar (10) makes a positive connection which is broken under excessive stress when a stone or the like is struck, the result of this being that the cutter (14) can rotate. The positive connection can be broken in this way in the elastic or plastic range if the parts engaging in one another are resilient or if, for example when an expansion bolt is used, the length of the bolt is increased when excessive load occurs. <IMAGE>

Description

DK 167795 B1DK 167795 B1

Opfindelsen angår en knivbjælke af den i krav l's indledning angivne art.The invention relates to a cutter bar of the kind specified in the preamble of claim 1.

En sådan knivbjælke er kendt fra AU-A-455.520. Ved hjælp af den her tilvejebragte drejeføring skal det opnås, at kniven 5 kan undvige drejende, når den rammer en fast genstand, og at kniven efter at have passeret forhindringen igen bliver ført tilbage i den oprindelige stilling som følge af på kniven indvirkende centrifugalkræfter. Denne driftstilstand er dog vanskelig at realisere, fordi drejebefæstigelsen ud fra syns-10 punktet om en pålidelig klipning ikke må være for løs, fordi der ellers ikke vil kunne opnås et upåklageligt snit og en tilbageføring som følge af centrifugalkraft på den anden side ikke mere er sikret ved en for høj friktionskraft. Selv hvis det ved at give afkald på strækningen som følge af centrifu-15 galkræfterne blev forsøgt at indstille friktionsslutningen således, at en udsvingning kun sker ved optræden af en overbelastning, så ville indstillingen af en hertil egnet friktionskraft være problematisk. Friktionskraften afhænger ganske vist i første række af den spænding eller normalkraft, som er 20 bestemt ved boltmøtrikkens tilspænding, men den er dog desuden væsentlig påvirket af friktionskoefficienten, som kan ændre sig under driften. Der sker så hyppigt allerede et tilbageslag af kniven, når modstanden ved klipningen af meget tæt græs vokser, eller omvendt sker udsvingningen ikke ved en for hård 25 indstillingen, når kniven bliver gravet ind i jorden eller bliver ramt af hårde fremmedlegemer.Such a cutter bar is known from AU-A-455,520. By means of the pivoting guide provided here, it must be achieved that the knife 5 can avoid turning when it hits a fixed object and that after passing the obstacle the knife is returned to its original position due to centrifugal forces acting on the knife. However, this mode of operation is difficult to realize because, from the viewpoint of a reliable mowing, the turning attachment must not be too loose, because otherwise an impeccable cut and return due to centrifugal force on the other hand will no longer be secured by too high a frictional force. Even if, by relinquishing the stretch due to the centrifugal forces, it was attempted to adjust the friction closure such that a fluctuation occurs only upon the occurrence of an overload, the adjustment of a suitable frictional force would be problematic. Although the frictional force depends primarily on the tension or normal force which is determined by the tightening of the bolt nut, it is, however, also substantially influenced by the coefficient of friction which can change during operation. Frequently, a backlash of the knife already occurs when resistance to mowing of very dense grass grows, or conversely, the swing does not occur at an excessively hard setting when the knife is dug into the ground or hit by hard foreign bodies.

Opfindelsen har derfor til formål at tilvejebringe en knivbjælke af den indledningsvis angivne art, som på simpel måde kan indstilles til et forudbestemt overbelastningsdrejningsmo-30 ment, som sikrer den tilstræbte beskyttelsesfunktion, men dog i normaldrift muliggør en sikker klipning også af tæt græs.It is therefore an object of the invention to provide a cutter bar of the kind initially specified which can be simply adjusted to a predetermined overload torque which ensures the desired protection function, but in normal operation also enables a secure mowing of dense grass.

Dette opnås ifølge opfindelsen ved, at knivbjælken er udformet som angivet i krav 1' s kendetegnende del. Ved at der er en afstand imellem de over for hinanden liggende cirkelrunde DK 16779b Bl 2 pladedele, kan der ved dette sted ikke være virksomme friktionskræfter. Disse friktionskræfter begrænses i det væsentlige til den koniske drejeføring. Som følge af det formsluttende indgreb imellem den i langsgående retning forløbende profile-5 ring og knivbærerpladens ribbe bestemmes i det væsentlige drejningsmomentet, ved hvilket pladen, som bærer kniven, slår tilbage, hvorved den koniske drejeføring ved tilbageslaget bliver virksom, hvilket forhindrer, at befæstigelsesbolten brækkes itu og kniven bliver slynget bort. Indstillingen af 10 luftspalten mellem de over for hinanden liggende plane flader af drej eføringen er dermed medbestemmende for indstillingen af udløsningsdrejemomentet, fordi der i denne spalte kan indstilles en kantning, over hvilken profileringen løber op på ribben og så kan glide af ved elastisk deformation.This is achieved according to the invention in that the cutter bar is configured as defined in the characterizing part of claim 1. Because there is a distance between the opposing circular circles DK 16779b B1 2 plate parts, there can be no effective frictional forces at this location. These frictional forces are essentially limited to the tapered rotation. As a result of the form-fitting engagement between the longitudinal profiling and the knife-carrier plate's ribs, the torque at which the plate carrying the knife strikes rests is essentially determined, thereby preventing the tapered pivoting at the kickback, preventing the fastening bolt is broken and the knife is thrown away. The setting of the air gap between the opposite planar surfaces of the pivot is thus co-determining the setting of the release torque, because in this slot an edge can be set over which the profiling runs on the rib and can then slip off by elastic deformation.

15 Der kendes ganske vist fra EP-A-0.136.988 allerede en dreje-sikring for de på en knivbjælke siddende knive, hvor den med en plan fladesektion forsynede kniv er spændt på en med plan flade forløbende del på enden af knivbjælken ved hjælp af skruebolten og et fra knivbæreren bortbøjet fremspring griber 20 formsluttende ind i en i længderetningen forløbende udskæring af knivbjælken. Herved bliver drej ef øringen dog kun opnået ved hjælp af forbindelsen, som skruebolten frembringer, og denne kan ved knivens anslag på en sten brække af, fordi knivbærerens hulrand under ugunstige omstændigheder direkte rammer på 25 bolten og således klipper den af.It is admittedly known from EP-A-0.136.988 that a rotary fuse is already known for the blades seated on a cutter bar, where the cutter provided with a flat surface section is clamped on a flat flat section at the end of the cutter bar. the screw bolt and a projection bent away from the knife carrier engages 20 form-fitting into a longitudinal cutout of the cutter bar. In this case, however, the rotation of the earring is achieved only by means of the connection which the screw bolt produces, and this can, by the impact of the knife on a stone, break off, because under the adverse circumstances the knife carrier's hollow edge directly hits the bolt and thus cuts it.

Andre fordelagtige udførelsesformer af opfindelsen er angivet i underkravene.Other advantageous embodiments of the invention are set forth in the subclaims.

Opfindelsen forklares nærmere nedenfor under · henvisning til tegningen, hvor 30 fig. 1 viser en del af en knivbjælke med påskruede knive udformet ifølge opfindelsen, fig. 2 et snit langs linien A-B i fig. 1, 3 DK 167795 B1 fig. 3 et snit langs linien C-D i fig. 1, og fig. 4 fra oven en kniv ifølge opfindelsen.The invention is explained in more detail below with reference to the drawing, in which FIG. 1 shows a portion of a knife bar with screwed-in knives designed in accordance with the invention; FIG. 2 is a section along line A-B of FIG. 1, 3 DK 167795 B1 fig. 3 is a section along the line C-D of FIG. 1, and FIG. 4 from above a knife according to the invention.

Knivbjælken 10 sættes med sit midterhul 12 på en motorplæneklippers med en lodret akse omløbende drivaksel og fastholdes 5 på denne ved hjælp af en spændmøtrik. På begge· ender er fastgjort udskiftelige knive 14, som på forløberkanten har et skær 16 og efter efterløberkanten er trukket opad som vindvinger 18, der fører græsset ind i en opfangningsbeholder.The cutter bar 10 is mounted with its center hole 12 on a motor lawn mower with a vertical axis orbiting drive shaft and is held 5 on it by means of a tensioning nut. Interchangeable blades 14 are attached on both ends, which have a cutting edge 16 on the precursor edge and are drawn upwardly as wind blades 18 which lead the grass into a catch container.

Den sig på begge sider udad tilspidsede knivbjælke har mod 10 hver side forløbende profileringer 20, som fra en midterste, hullet 12 omsluttende udprægning forløber mod koniske drejefø-ringer 24 på hver ende af den toarmede knivbjælke 10. På hver knivbjælkeende er der koncentrisk i forhold til hver af de koniske drejeføringer tildannet et gennemgående hul 26, hvori 15 en møtriks 30 forsatte del 28 er indsat. Hullet 26 og den forsatte del 28 kan udformes polygonalt for at tilvejebringe en sikring mod drejning af møtrikken. Møtrikken 30 er fortrinsvis svejset fast på knivbjælken, hvorved der opnås en simpel montage, og en forkert montering af kniven 14 udelukkes.The cutter bar, which is tapered outwardly on both sides, has 10 profiles on each side extending 20, extending from a central hole 12 enclosing projection towards tapered rotary guides 24 on each end of the two-armed knife bar 10. On each knife bar end there is concentric relationship. to each of the tapered pivots is provided a through-hole 26, in which 15 a portion 28 of the nut 30 is inserted. The hole 26 and the offset portion 28 can be formed polygonally to provide a lock against the rotation of the nut. The nut 30 is preferably welded to the cutter bar, thereby obtaining a simple mounting and improper mounting of the knife 14.

20 Hver kniv 14 har en halvrund bærerplade 32, som har et koncentrisk gennemgående hul 34 til en bolt 36. Hullet 34 er omgivet af en til drej eføringen 24 svarende koncentrisk drejeføring 38, der især kan ses i fig. 2, og som passer ind i knivbjælkens drejeføring 24. Som det også kan ses i fig. 2, har kniv-25 bjælkens henholdsvis knivens inden for den koniske drejeføring liggende cirkulære pladedele 40 henholdsvis 42 i sammenbygget tilstand en afstand 44 til hinanden. Denne afstand i befæsti-gelsesområdet udgår ca. 0,8 mm, og kniven kan derved virke som tallerkenfjeder, hvorved der tilvejebringes en flad skrueka-30 rakteristik, og et sikringselement, såsom en fjedrende underlagsskive eller lignende kan udelades.Each knife 14 has a semicircular support plate 32 which has a concentric through hole 34 to a bolt 36. The hole 34 is surrounded by a concentric turning guide 38 corresponding to the guide 24, which can be seen in particular in FIG. 2, which fits into the rotary guide of the cutter bar 24. As can also be seen in FIG. 2, the circular plate portions 40 and 42 of the bar and the knife, respectively, of the beam and the knife, respectively, have a distance 44 to each other in the assembled state. This distance in the attachment area is deleted approx. 0.8 mm, and the knife may thereby act as a plate spring, thereby providing a flat screw characteristic and a securing element such as a resilient washer or the like.

Som vist i fig. 3 og 4 har knivbærerpladen 32 en fra den koni- 4 DK 167795 B1 ske drejeføring 38 i radial retning forløbende ribbe 46, som formsluttende indgriber i knivbjælkens 10 profilering 20.As shown in FIG. 3 and 4, the knife support plate 32 has a radial guide 38 extending radially extending from the conical 4 DK 167795 B1, which formally engages in the profiling 20 of the cutter bar 10.

Som vist i fig. 2 er knivbjælkens 10 pladedel 40 på den mod knivpladen 32 vendende side forsynet med et hullet 26 omgiven-5 de spor 48, som danner et mellemled og gør det nemmere for kniven at dreje af, når den påvirkes af en overbelastning. Sporet 48 tilvejebringes ved fortanding af "profil"-stansemøtrikker og opstår ved prægning af møtrikken. I stedet for dette og/eller desuden kan boltene 36 være udformet som eks-10 pansionsbolte, der trækkes ud og lader kniven undvige, når der optræder en aksial overbelastning. Til dette formål kan boltene 36 være forsynet med et rundtgående spor.As shown in FIG. 2, the plate portion 40 of the cutter bar 10 on the side facing the knife plate 32 is provided with a hole 26 surrounding groove 48 which forms an intermediate joint and makes it easier for the knife to pivot when affected by an overload. The groove 48 is provided by toothing of "profile" punching nuts and arises by embossing the nut. Instead of this and / or in addition, the bolts 36 may be designed as expansion bolts which are pulled out and avoid the knife when an axial overload occurs. For this purpose, the bolts 36 may be provided with a circumferential groove.

Kniven 14 bliver med sin koniske drejeføring 38 centreret i knivbjælkens koniske drejeføring 24 og kan ved påvirkning af 15 skærekanten 16 med en hård genstand, f.eks. en sten, dreje af, uden at der er fare for, at kniven eller dele af denne springer af og slynges ude. Ved påvirkning af en overbelastning kan knivens formsluttende i knivbjælkens profilering 20 indgribende ribbe 46 løfte sig ud og dreje sig under friktions slutning.The knife 14, with its tapered guide 38, is centered in the tapered guide 24 of the cutter bar and, upon impact of the cutting edge 16, can with a hard object, e.g. a stone, pivoting, without the danger of the knife or parts of it breaking off and being thrown out. Under the influence of an overload, the cutting end of the knife in the profile bar 20 engaging rib 46 can lift out and rotate during the friction end.

20 Formslutningen mellem profilringen 20 og ribben 46 er desuden dimensioneret således, at forekommende driftskræfter på sikker måde kan overføres, men dog således at ved påvirkning af en hård genstand springer kniven ud af indgreb og kobles fra.The mold closure between the profile ring 20 and the rib 46 is furthermore dimensioned so that any operating forces can be safely transmitted, but, however, so that when the impact of a hard object is cut, the knife comes out of engagement and disengages.

Ved hjælp af centreringen via de koniske drejeføringer opnås 25 en mindre ubalance end ved de kendte skrueforbindelser, hvor det uundgåelige skruebolt spillerum ikke muliggør en eksakt nøjagtig indstilling. Denne indretning har også den fordel, at kun en del af den fra kniven til befæstigelseselementet videreførte belastning optages, fordi en stor del af belastningen, 30 især skærebelastningen, optages af den koniske centrering og ikke behøver at optages af skruen, og belastningen optages derved af centreringen og ikke af skruen, og centreringen bliver derved ikke belastet til klipning.By means of the centering via the tapered pivots, a smaller imbalance is obtained than with the known screw connections, where the inevitable screw bolt clearance does not allow an exact precise adjustment. This device also has the advantage that only part of the load transferred from the knife to the fastening element is absorbed because a large part of the load, especially the cutting load, is absorbed by the taper centering and does not have to be absorbed by the screw, and the load is thereby absorbed by the screw. the centering and not the screw, and the centering is thereby not loaded for cutting.

Claims

A lawn mower cutter bar (10), which is held in the center on a vertical drive shaft and carries on both its radially outermost 10 ends, knives which are interchangeably secured by a screw attachment, the carrier plates (32) of the blades (14) being biased thus over tapered rotating guides (24, 38) on the cutter bar (10) with friction by means of a screw bolt (36) arranged concentrically with the turning guide 15 in such a way that the blades (14) can avoid by overloading, characterized in that the cutter bar has a longitudinal profiling (20) in which a rib (46) rests on the knife support plate (32) form-fitting, that between the opposite surfaces of the 20 circular plate parts (40, 42) of the cutter bar (10) and the cutter support plate (32) surrounding the bolt hole (34) are a distance (44) and that plastic and / or elastically deformable parts of the cutter attachment overload cancel the mold closure between the cutter bar, the profiling and the knife support rib.

Knife bar according to claim 1, characterized in that the knife bar (10) and / or the knife support plate (32) is provided with a groove (48) in the part enclosing the through bolt hole.

Knife bar according to claim 1, characterized in that 30 is provided with an expansion bolt (36) as a fastening bolt. Knife bar according to one or more of claims 1-3, characterized in that the bolt nut (30) is held against LJIV IQ / / Ο I 6 rotation of the knife support plate (32).

The cutter bar according to claim 4, characterized in that the bolt nut (30) is punched or welded to the cutter bar (10).

Knife bar according to one or more of claims 1-5, characterized in that the blade plate is pulled upwards to form a wind vane (18).