DK141213B

DK141213B - The piston-cylinder mechanism.

Info

Publication number: DK141213B
Application number: DK520272A
Authority: DK
Inventors: Arne Engquist
Original assignee: Bahco Verktyg Ab
Priority date: 1971-10-27
Filing date: 1972-10-20
Publication date: 1980-02-04
Also published as: FR2158989A5; DK141213C; JPS528941B2; SE417546B; JPS4861870A; DE2251202B2; GB1375288A; CA971061A; IT969880B; DE2251202A1

Description

i 141213in 141213

Opfindelsen angår en stempel-cylindermekanisme med et væsentligt spillerum imellem stemplet og cylinderen og med en fleksibel manchet, der omslutter stemplets periferi og ligger tætnende an imod cylindervæggen, og hvor stemplet bærer 5 en styrering, hvis yderside ligger glidende an imod cylindervæggen, og hvis imod stemplet vendende inderside er konveks buet, hvilken styrering er lejret i en rille i stemplet, der er anbragt imellem manchetten og stemplets imod cylinder-rummet vendende ende,og har en i tværsnit hovedsagelig ret-10 liniet bund.The invention relates to a piston-cylinder mechanism with a substantial clearance between the piston and the cylinder and with a flexible cuff which encloses the circumference of the piston and seals against the cylinder wall, and the piston carries a guide whose outer surface slides against the cylinder wall and if against the inner face of the plunger is convexly curved, said guide being mounted in a groove in the plunger disposed between the sleeve and the end of the plunger facing the cylinder compartment, and having a transverse, generally rectilinear bottom.

Nærværende opfindelse er især tænkt anvendt til stempel-cy-lindermekanismer, der er udsat for meget store belastninger, f.eks. dunkrafter, der anvendes på skibsværfter, hvor løftekraften kan være 100 tons eller mere. Med løftekraft menes 15 trykkraft, idet mekanismen kan være anbragt i enhver arbejdsstilling imellem lodret og vandret stilling. Hvor der forekommer så store trykkræfter,er det vanskeligt at tilvejebringen en tilstand, hvor kraftens retning falder nøjagtig sammen med cylinderens akse,og skråbelastninger kan derfor sjæl-20 dent undgås. Derved opstår der især ved stor stempeldiameter let rivning, som kan have alvorlige følger, idet den oprevne cylinderflade vil kunne ødelægge tætningsmanchetten, hvorved mekanismen bliver helt eller delvis ubrugelig.In particular, the present invention is intended to be used for piston-cylinder mechanisms subjected to very high loads, e.g. canisters used at shipyards where the lifting force can be 100 tonnes or more. By lifting force is meant 15 compressive force, the mechanism being located in any working position between vertical and horizontal position. Where such high compressive forces occur, it is difficult to provide a state in which the direction of force coincides exactly with the axis of the cylinder, and oblique loads can therefore be avoided. In this way, especially at large piston diameters, slight tearing occurs, which can have serious consequences, as the torn cylinder surface can damage the sealing cuff, thereby rendering the mechanism completely or partially useless.

Fra US patentskrift nr. 3.333.513 kendes en stempel-cylinder-25 mekanisme, der er udformet i hovedsagen som angivet. Styreringen består af en opslidset ring, der har et antal langs ringens længderetning fordelte indsnit, som danner broer med forholdsvis lille tværsnit imellem klodser af væsentlig større tværsnit. Disse klodser danner glideblokke, hvis yderside 30 ligger an imod cylindervæggen, medens indersiden i tværsnit danner en konveks bue,der ligger an imod den i tværsnit retlinede bund af rillen i stemplet.US Patent No. 3,333,513 discloses a piston-cylinder-25 mechanism designed in the main case as disclosed. The guide ring consists of a slit ring having a number of incisions distributed along the longitudinal direction of the ring which form bridges of relatively small cross-section between bricks of substantially larger cross-section. These bricks form sliding blocks, the outside of which 30 abuts against the cylinder wall, while the inside cross section forms a convex arc which abuts the transverse rectilinear bottom of the groove in the piston.

Ved skråstilling af stemplet i forhold til cylinderen, vil de forskellige glideblokke blive forskudt varierende stykker 141213 2 i cylinderens aksiale retning samtidig med, at styreringen som helhed forvrides,således at ydersiden af hver glideblok kan sammenfalle med cylindervæggen. Styreringens oprindelige cirkulære form forandres til en elliptisk,og dette formfor-5 andringsarbejde forårsages af tryk fra cylindervæggen imod glideblokkenes øvre, henholdsvis nedre kantpartier. Derved kan fladetrykket blive betydeligt, især da kraften kan overføres gennem en enkelt eller måske to glideblokke på hver side. Styreringen i denne kendte mekanisme er således, hver-10 ken stiv eller helt lukket, men er forholdsvis meget fleksibel, hvorfor kraftkoncentration til den enkelte glideblok ikke kan undgås ved skråbelastning.By slanting the piston relative to the cylinder, the various sliding blocks will be displaced varying pieces in the axial direction of the cylinder while simultaneously distorting the guide so that the outside of each sliding block can coincide with the cylinder wall. The original circular shape of the guide ring changes to an elliptical, and this shape-changing work is caused by pressure from the cylinder wall against the upper and lower edge portions of the sliding blocks, respectively. Thereby the surface pressure can become considerable, especially as the force can be transmitted through a single or perhaps two sliding blocks on each side. Thus, the control of this known mechanism is neither rigid nor fully closed, but is relatively very flexible, and therefore force concentration for the individual sliding block cannot be avoided by oblique loading.

Det stærke, koncentrerede tryk imod cylindervæggen vil ved store belastninger kunne beskadige væggen ved rivning.The strong, concentrated pressure against the cylinder wall can damage the wall by tearing at high loads.

15 Mekanismen ifølge nærværende opfindelse er ejendommelig ved, at styreringen er en endeløs ring af i hovedsagen deformationsbestandigt materiale,og har i hovedsagen konstant tværsnit.The mechanism of the present invention is characterized in that the guide ring is an endless ring of substantially deformation-resistant material and generally has a constant cross-section.

Den lukkede og formstabile styrering ifølge denne udformning 20 bibeholder sin orientering vinkelret på cylinderens længdeakse, og skråkræfter optages i princippet af halvdelen af ringen, hvorved trykket imod cylindervæggen bliver forholdsvis lille. Kun en helt lukket og formstabil styrering med i hovedsagen konstant tværsnit kan ved skråstilling af stemplet 25 beholde sin orientering i cylinderen. Det konstante tværsnit giver ikke alene stivhed til ringen, men forøger arealet af den flade, der ligger an imod cylindervæggen, således at fladetrykket bliver forholdsvis lille i sammenligning med den kendte styrering.The closed and form-stable guide according to this embodiment 20 maintains its orientation perpendicular to the longitudinal axis of the cylinder, and oblique forces are taken up in principle by half of the ring, whereby the pressure against the cylinder wall becomes relatively small. Only a fully closed and form-stable guide with substantially constant cross-section can, when inclined by the piston 25, retain its orientation in the cylinder. The constant cross section not only provides stiffness to the ring, but increases the area of the surface abutting the cylinder wall so that the surface pressure becomes relatively small compared to the known guide ring.

30 Af de anførte grunde, glider styreringen ifølge opfindelsen i cylinderen med sine endeplaner vinkelret på cylinderens akse, og styreringen beholder sin korrekte orientering i cylinderen, selv om stemplet er noget skråtstillet i forhold 141213 3 til denne, således at styreringen og cylinderen altid har samvirkende cylindriske flader af forholdsvis stor størrelse, hvorved cylinderfladen ekånes.For the reasons stated, the steering wheel according to the invention slides into the cylinder with its end planes perpendicular to the axis of the cylinder, and the steering retains its correct orientation in the cylinder, although the piston is somewhat inclined relative to it, so that the steering and cylinder always cooperate. cylindrical surfaces of relatively large size, thereby echoing the cylinder surface.

I det følgende forklares opfindelsen under henvisning til 5 tegningen, som viser den ene ende af en stempel-cylindermeka- nisme ifølge opfindelsen set fra siden delvis i snit.In the following, the invention is explained with reference to the drawing, which shows one end of a piston-cylinder mechanism according to the invention, partially cut away from the side.

Mekanismen har en cylinder 1 og et i denne lejret stempel 2. Omkring stemplets periferi er der anbragt en tætningsmanchet 3, som på kendt måde er sammensat af flere ringe af forskelligt 10 materiale og indrettet tilstrækkelig bøjeligt til at tilvejebringe en god tætning, såvel når den står stille, som nåf den glider langs med cylindervæggen.The mechanism has a cylinder 1 and a piston 2 enclosed therein. Around the circumference of the piston, a sealing sleeve 3 is provided, which is known in the manner of several rings of different material and arranged sufficiently flexibly to provide a good seal, even when stands still as it slides along the cylinder wall.

For tilførsel af trykvæske til cylinderrummet 4 er der anbragt en kanal 5 mellem dette og en snapkoblingshalvdel 6, som er 15 indrettet til at forbinde mekanismen til en ikke vist tryk-væskekilde ved hjælp af en slange.For supplying pressure fluid to the cylinder compartment 4, a channel 5 is arranged between this and a snap coupling half 6 which is arranged to connect the mechanism to a pressure fluid source not shown by means of a hose.

Stemplet 2 er hult og er åbent imod cylinderbunden for at give plads til et antal trækfjedre 7, der tjener som tilbageføringsfjedre for stemplet ved aflastning af væsketrykket. Fjed-20 rene er fastgjort dels i stemplet, hvilket ikke fremgår af tegningen, og dels i cylinderbunden ved hjælp af på tegningen kun ufuldstændig viste kendte fastgørelseselementer 8.The piston 2 is hollow and is open against the cylinder bottom to accommodate a plurality of tensile springs 7 which serve as return springs for the piston upon relieving the fluid pressure. The springs are secured partly in the piston, which is not shown in the drawing, and partly in the cylinder bottom by means of only known fastening elements 8 shown in the drawing.

Stemplet 2 har imellem manchetten 3 og sin mod cylinderrrummet 3 vendte ende et perifert ringformet spor 9, hvori et styr 10 25 er begrænset bevægeligt lejret. Dette styr kan være fremstillet f.eks. af stål eller hovedsagelig deformeringsstabilt formstof og ligger glidende an mod cylindervæggen uden at overtage manchettens tætningsfunktion.The piston 2 has between the cuff 3 and its end facing the cylinder space 3 a peripheral annular groove 9, in which a guide 10 25 is constrained to be movably mounted. This guide may be manufactured e.g. of steel or mainly deformation-stable plastic and slides abut against the cylinder wall without taking over the sealing function of the cuff.

Styret 10 er på sin underside hovedsagelig cylindrisk og har 30 en diameter, som kun ubetydeligt underskrider cylinderen l's inderdiameter i løbet. Det viste snit gennem ringen 10 har således en i det væsentlige ret profil på ydersiden. På in- 141213 4 dersiden er profilen derimod konveks, således at kun en midterdel har mulighed for at ligge an imod sporet 9's bund, som har en i hovedsagen ret profillinie.The guide 10 is substantially cylindrical on its underside and has a diameter which is only slightly lower than the inner diameter of the cylinder 1 in the barrel. Thus, the section shown through the ring 10 has a substantially straight profile on the outside. On the other hand, the profile, on the other hand, is convex, so that only one center portion has the possibility of abutting the bottom of the groove 9, which has a substantially straight profile line.

En kanal 11 mellem sporet 9's bund og stemplet 21 s indre hul-5 rum sætter i trykudjævnende og smørende hensigt cylinderrummet 4 i forbindelse med såvel rummet mellem sporets bund og styret 10 som rummet mellem manchetten 3 og styret.A channel 11 between the bottom of the groove 9 and the inner cavity of the piston 21 puts in pressure-lubricating and lubricating purpose the cylinder space 4 in connection with both the space between the bottom of the groove and the guide 10 and the space between the cuff 3 and the guide.

Sporet 9's begrænsningsvæg i aksial retning indad mod manchetten 3 udgøres af en fast ansats 12 i form af en diameterfor-10 andring på stemplet. Sporets modsatte begrænsningsvæg udad 'mod stemplets ende dannes af en låsering 13, der som møtrik er anbragt på stemplets til dette formål gevindskårne endedel. Rummet mellem den af ansatsen 12 dannede begrænsningsvæg og den af låseringen 13 dannede er tilstrækkelig stort 15 til at give styret 10 en vis kæntringsmulighed. Styrets yderside mod cylindervæggen er ved begge ender jævnt afrundet, og ringen har i snit en ydre profil, som er afsluttet af en stor radius i overgangen til ringens respektive endeplan.The restriction wall of the groove 9 in the axial direction towards the cuff 3 is constituted by a fixed shoulder 12 in the form of a change of diameter on the piston. The opposite limiting wall of the groove outwardly towards the end of the piston is formed by a locking ring 13 which, as a nut, is placed on the threaded end portion of the piston for this purpose. The space between the restriction wall formed by the shoulder 12 and that formed by the locking ring 13 is sufficiently large 15 to give the guide 10 a certain level of opportunity. The outside of the handlebar against the cylinder wall is evenly rounded at both ends, and the ring has on average an outer profile, which is completed by a large radius in the transition to the respective end plane of the ring.

Den beskrevne mekanisme forebygger en sådan skråstilling af 20 indbyrdes glidende deles kontaktflader, som ville kunne medføre rivningsrisiko. De trykkræfter, som fremkommer mellem stemplet og cylindervæggen under skrå belastning, optages af styret 10, som tillader en vis skråstilling af stemplet uden at hindre den glidende samvirken med cylindervæggen. Graden 25 af tilladt skråstilling kan vælges ved at tilpasse de samvirkende deles indbyrdes bevægelighed i tværretningen, først og fremmest styret 10*s bevægelighed i sporet 9. En konveks inderprofil af styret forøger denne bevægelighed. Utilsigtede bivirkninger af styret med hensyn til manchettens 30 funktion forebygges ved hjælp af kanalen 11. Udførelsesformen med en låsering 13 til dannelse af sporet 9 giver en enkel montering af manchetten og styret, samt muliggør hurtig udskiftning af disse.The described mechanism prevents such slanting of the 20 contact surfaces of mutually sliding parts which could cause tearing risk. The compressive forces produced between the piston and the cylinder wall under oblique load are taken up by the guide 10, which allows a certain inclination of the piston without obstructing the sliding interaction with the cylinder wall. The degree 25 of permissible inclination can be selected by adjusting the mutual movement of the interacting parts in the transverse direction, first of all guiding the movement of the 10 * in the groove 9. A convex inner profile of the guide increases this movement. Unintended side effects of the guide with respect to the function of the sleeve 30 are prevented by means of the channel 11. The embodiment with a locking ring 13 for forming the groove 9 provides for easy mounting of the sleeve and the guide, and allows for rapid replacement thereof.