NO156582B

NO156582B - HYDRAULIC CYLINDER.

Info

Publication number: NO156582B
Application number: NO834458A
Authority: NO
Inventors: Bjoern Watvedt
Original assignee: Kverneland As
Priority date: 1983-12-05
Filing date: 1983-12-05
Publication date: 1987-07-06
Also published as: NO834458L; SE8406117D0; ES8602211A1; ES538245A0; DK565584D0; NZ210416A; GR81171B; GB2150639B; NO156582C; DE3444130A1; FI844758A0; DK565584A; AU3631284A; GB8430545D0; SE8406117L; SE458875B; FI844758L; GB2150639A; CH659859A5; FR2556055B1

Description

Ved bruk av hydrauliske sylindre forekommer det relativt ofte at en sylinder med stemplet i en vilkårlig utgangsposisjon aktiveres for å gjøre et slag, hvoretter det er ønskelig at stemplet kan føres tilbake slik at det automatisk stopper i samme utgangsposisjon. Dette lar seg ikke gjøre med de kjente hydrauliske sylindre, med mindre stemp-lets utgangsposisjon er en av de to endeposisjoner hvor stemplet bunner mot den ene eller den andre sylindergavl. When using hydraulic cylinders, it occurs relatively often that a cylinder with the piston in an arbitrary starting position is activated to make a stroke, after which it is desirable that the piston can be moved back so that it automatically stops in the same starting position. This cannot be done with the known hydraulic cylinders, unless the starting position of the piston is one of the two end positions where the piston bottoms against one or the other cylinder end.

Som et eksempel på hvor det er behov for en hydraulisk sylinder der stemplet fra en vilkårlig utgangsposisjon kan aktiveres for å gjøre et slag, hvoretter det er ønskelig at stemplet kan føres tilbake slik at det automatisk stopper i samme utgangsposisjon, kan nevnes en vendeplog med trinnløst stillbar pløyebredde. Før plogen vendes, svinges den inn ved hjelp av en hydraulisk sylinder fra den innstilte pløye-bredde til minste pløyebredde for å få minst mulig vende-moment og størst mulig stabilitet under vendeoperasjonen. Etter vendeoperasjonen skal plogen ved hjelp av nevnte hydrauliske sylinder svinges tilbake til den samme pløye-bredde igjen. As an example of where there is a need for a hydraulic cylinder where the piston can be activated from an arbitrary starting position to make a stroke, after which it is desirable that the piston can be moved back so that it automatically stops in the same starting position, a reversible plow with stepless adjustable plow width. Before the plow is turned, it is swung in with the help of a hydraulic cylinder from the set plow width to the smallest plow width in order to obtain the least possible turning moment and the greatest possible stability during the turning operation. After the turning operation, the plow must be swung back to the same plow width again with the help of the aforementioned hydraulic cylinder.

Fra DE off.skrift 2658393 er det kjent å begrense slaglegden i en fluidsylinder ved hjelp av et løst stempel i sylinderen, hvorved sylinderen blir delt i tre rom, over, under og mellom stemplene, og der det ene rommets utvidelse benyttes til å begrense variasjonsmuligheten mellom de andre rommene og dermed begrense sylinderens slaglengde. From DE official publication 2658393 it is known to limit the stroke in a fluid cylinder by means of a loose piston in the cylinder, whereby the cylinder is divided into three chambers, above, below and between the pistons, and where the expansion of one chamber is used to limit the possibility of variation between the other rooms and thus limit the stroke of the cylinder.

Formålet med oppfinnelsen ifølge nevnte off.skrift er først og fremst å frembringe en kompakt hydraulisk eller pneu-matisk sjalte-sylinderanordning hvor sylinderens slaglengde uten vanskelighet kan innstilles trinnløst fra utsiden, uten demontering, etter behov. For dette formål benyttes en sylinder med et todelt stempel hvor den ene stempeldel er fast forbundet med stempelstangen, og hvor den andre stempeldel er lagret aksialt forskyvbar på stempelstangen. The purpose of the invention according to the aforementioned official document is primarily to produce a compact hydraulic or pneumatic switching cylinder device where the stroke length of the cylinder can be easily adjusted steplessly from the outside, without disassembly, as needed. For this purpose, a cylinder with a two-part piston is used where one piston part is fixedly connected to the piston rod, and where the other piston part is stored axially displaceable on the piston rod.

Det er forskjellige muligheter for aksialforskyvning av stempeldelene i forhold til hverandre, eksempelvis ved hjelp av en gjengeforbindelse og en kontramutter. Det er naturlig-vis også mulig å anvende distansbøssinger og lignende. There are different possibilities for axial displacement of the piston parts in relation to each other, for example by means of a threaded connection and a counter nut. It is naturally also possible to use distance bushings and the like.

For lett å kunne stille om avstanden mellom de to stempeldeler, er stempelstangen forsynt med en ventileringsutboring som munner ut mellom de to stempeldeler, og som fører til det ytre. In order to easily adjust the distance between the two piston parts, the piston rod is provided with a ventilation bore that opens out between the two piston parts, and which leads to the outside.

Sylinderen som er kjent fra DE off.skrift 2658393, tilfreds-stiller imidlertid ikke det behov som er nevnt ovenfor. However, the cylinder which is known from DE official publication 2658393 does not satisfy the need mentioned above.

Formålet med nærværende oppfinnelse er å fremskaffe en hydraulisk sylinder som, etter at den fra en vilkårlig utgangsposisjon er aktivert og har gjort et slag, kan føres tilbake slik at den automatisk stopper i samme utgangsposisjon, altså en hydraulisk sylinder med "hydraulisk minne". Formålet oppnås ved en hydraulisk sylinder med de trekk som er angitt i det etterfølgende patentkrav. The purpose of the present invention is to provide a hydraulic cylinder which, after it has been activated from an arbitrary starting position and has made a stroke, can be moved back so that it automatically stops in the same starting position, i.e. a hydraulic cylinder with "hydraulic memory". The purpose is achieved by a hydraulic cylinder with the features specified in the subsequent patent claim.

Et utførelseseksempel av oppfinnelsen er vist på tegningen som delvis i snitt viser en hydraulisk sylinder ifølge oppfinnelsen . An embodiment of the invention is shown in the drawing, which partially shows a hydraulic cylinder according to the invention in section.

På tegningen betegner henvisningstallet 1 den hydrauliske sylinders sylinderrør med fremgavl 2, bakgavl 3, stempelstang 4 med stempel 5 og klauv 6. Dessuten er det i sylin-derrøret 1 anbrakt et løst stempel 7 mellom stemplet 5 og bakgavlen 3, slik at det dannes et rom 8 mellom stemplet 5 og det løse stempel 7. Rommet 8 kan bringes til å kommuni-sere med et hydraulikkanlegg (ikke vist på tegningen) via en aksial boring 9 i stempelstangen 4 og en oljeport 10 i klauven 6. For øvrig er fremgavl 2 og bakgavl 3 på vanlig måte utstyrt med oljeporter 11 henholdsvis 12. In the drawing, the reference number 1 denotes the hydraulic cylinder's cylinder tube with front end 2, rear end 3, piston rod 4 with piston 5 and pawl 6. In addition, a loose piston 7 is placed in the cylinder tube 1 between the piston 5 and the rear end 3, so that a space 8 between the piston 5 and the loose piston 7. The space 8 can be brought into communication with a hydraulic system (not shown in the drawing) via an axial bore 9 in the piston rod 4 and an oil port 10 in the pawl 6. Otherwise, front end 2 and rear end 3 in the usual way equipped with oil ports 11 and 12 respectively.

Den hydrauliske sylinder ifølge oppfinnelsen virker på følgende måte: Når oljeportene 10 og 11 tilkoples et hydraulikkanlegg, kan stemplet 5 drives frem og tilbake mellom det løse stempel 7, som da vil ligge an mot bakgavlen 3, og sylinderens fremgavl 2 og kan stoppes på vilkårlig sted. The hydraulic cylinder according to the invention works in the following way: When the oil ports 10 and 11 are connected to a hydraulic system, the piston 5 can be driven back and forth between the loose piston 7, which will then rest against the rear end 3, and the cylinder's front end 2 and can be stopped at any place.

Med stemplet 5 stoppet på vilkårlig sted i sylinderen og stengt forbindelse mellom oljeport 10 og hydraulikkanlegg, men åpen forbindelse mellom oljeportene 11, 12 og hydraulikkanlegget, kan stemplet 5 fra denne utgangsstilling alltid drives helt ut mot fremgavl 2, men stemplet 5 kan ikke drives lenger inn i sylinderen enn til nevnte utgangsstilling, hvor det løse stempel 7 kommer til anlegg mot sylinderens bakgavl 3. Det er altså oljemengden i rommet 8 mellom stemplet 5 og det løse stempel 7 som bestemmer den såkalte "sammentrukket lengde" av den hydrauliske sylinder, idet stemplet 5, det løse stempel 7 og mellomliggende større eller mindre oljemengde i rommet 8 fungerer som ett stempel når det er stengt forbindelse mellom oljeport 10 og hydraulikkanlegg, men åpen forbindelse mellom oljeportene 11, 12 og hydraulikkanlegget. With the piston 5 stopped at any place in the cylinder and the connection between the oil port 10 and the hydraulic system closed, but the connection between the oil ports 11, 12 and the hydraulic system open, the piston 5 can always be driven completely out towards the front end 2 from this starting position, but the piston 5 cannot be driven any further into the cylinder than to the aforementioned starting position, where the loose piston 7 comes into contact with the rear end of the cylinder 3. It is therefore the amount of oil in the space 8 between the piston 5 and the loose piston 7 that determines the so-called "contracted length" of the hydraulic cylinder, as the piston 5, the loose piston 7 and the intermediate larger or smaller quantity of oil in the space 8 function as one piston when there is a closed connection between the oil port 10 and the hydraulic system, but an open connection between the oil ports 11, 12 and the hydraulic system.

Claims

Device for hydraulic cylinder which mainly consists of cylinder tube (1) with front end (2), rear end (3), piston rod (4) with piston (5) and pawl (6) or similar, as well as oil ports (11, 12) in or at the front end (2) and the rear end (3) arranged for connection to a hydraulic source, and where a loose piston (7) is placed in the cylinder tube (1) between the piston (5) and the rear end (3), so that it forms or a space (8) can be formed between the piston (5) and the loose piston (7), as the piston rod (4) and claw (6) are designed with an axial bore (9) which at one end has an open connection with the space ( 8) between the piston (5) and the loose piston (7), characterized in that the bore (9) at the other end opens into an oil port (10) in the claw (6) arranged for connection to the hydraulic source in such a way , that when the connection between the hydraulic source and the oil port (10) in the claw (6) as well as the connection between the hydraulic source and the oil port (11) in or at the front end (2) to is opened and the connection between the hydraulic source and the oil port (12) in or near the rear end (3) is closed, the piston (5) can be driven back and forth between the loose piston (7) - which will then rest against the rear end (3) - and the front end (2) of the cylinder (1) and can be stopped at any point in the cylinder (1); and when the piston (5) is stopped at any point and the connection between the hydraulic source and the oil port (10) in the claw (6) is closed, but the connections between the hydraulic source and the oil ports (11 and 12) in or at the front end (2) and the rear end (3) is opened, the piston (5) can always be driven completely out towards the front end (2) from the aforementioned initial position, but the piston (5) cannot be driven further into the cylinder (1) than to the aforementioned initial position, where the loose piston (7 ) comes into contact with the rear end (3) of the cylinder (1), whereby the hydraulic cylinder, after it has been activated from an arbitrary starting position and has made a stroke, can be moved back so that it automatically stops in the same starting position.