Hydraulic cylinder Tie Rod Design - imperial - Duncan Rogers

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MOUNTING INFORMATIONFixed Centreline MountsCentreline mounts are generallyconsidered to be the best type of fixedmounting since the thrust from the pistonrod is taken at a mounting surface that iscoincident with the cylinder centreline.Use of this type of mount can eliminatepossible problems resulting from cylindersway and flexure of cylinder components.Flange MountsAlthough flange mounts are consideredto be of the centreline type, caution mustbe exercised as they can be applied insuch manner as to cause them to be of anon-centreline nature. Whenever acylinder is mounted by the backside of aflange, a condition exists where flexure ofthe flange resulting in fatique failure ofthe mounting bolts or flange retainerfasteners is possible.(See Fig. A)Backside Flange MountFig. AThe only type of flange recommended forbackside mounting is the style where thefull thickness of the head or the capserves as the flange (Styles FHF or RHF).Front Head Flange Style FHFRear Head Flange Style FHFSelection of a flange mounting styledepends, in part, upon whether themajor force applied to the machinemember will result in tension orcompression of the cylinder rod. Rearflange mounting styles are best for thrustloads (rod in compression and frontflange mounting styles are best where therod is stressed in tension).Rectangular flange mounts (Styles FF andRF) are not recommended for use withpressures in excess of 1000 psi nor shouldthey be used with strokes longer than 36inches.Front Flange Styles FF & FFXRear Flange Styles RF & R F XRegardless of mount, whenever a longstroke cylinder is employed, considerationshould be given to additional support –see page 16 for long stroke cylinder data.Where the larger size of the square flangecan be accommodated (Styles FFX andRFX), they may be used with full pressurerating of the cylinder and with longstrokes. The best styles of flange mount,regardless of application, are the FHF andRHF Mounts. The RHF Mount has thesame mounting hole pattern and thesame rectangular flange dimension as theRF Mount (see pages 22 and 23),therefore, with longer mounting screwsand consideration for a slightly shorteroverall length, the RHF Mount can besubstituted for the RF. The FHF Mount hasthe same hole pattern and rectangularflange dimensions as the FF Mount. Tosubstitute the FHF Mount for that of theFF, it may be necessary to use spacers tofill in the dimensions previously occupiedby the flange. See our accessory page(page 6) for Front Head Flange SpacerBars. The spacers are employed as shownin Fig.B. Front Flange styles of mountingare dimensioned on pages 20 and 21.Fig. BCentreline Lug MountsThis style of mount is one of the bestfixed mounts. It is not, however, one ofthe more popular mounts since it is notthe most convenient to utilise. Whenused at higher pressure ranges or undershock conditions, the lugs should bedowelled to the machine. This style ofmount has room for dowel pins in themounting lugs. Doewlling should be doneat one end of the cylinder only (especiallyimportant on long strokes) due to thedeflection that takes place under load.Cylinders should never be pinned acrosscorners. This can result in severe warpingwhen the cylinder is subjected tooperating temperatures and pressures.Dimensions for Centreline Lug Mounts aregiven on pages 24 and 25.Centreline Lug Style CLTie Rod Extended MountsTie Rod Extended cylinders are availablewith the tie rods extended front (StyleFX), with the tie rods extended rear (StyleRX) or both ends (Style BX). Frequentlycylinders are ordered with tie rodsextended on one end in addition toanother mount. The extended tie rods arethen utilised for the mounting of othersystems or machine components.Tie Rod ExtendedStyles FX, RX, & BXShould the mounting be such that theoverhung weight of the cylinder is borneby the extended tie rods, additionalsupport may be required, especially if thecylinder has a long stroke (see page 16).From a thrust standpoint, tie rodextended mounts are good, stable ones.Dimensions for tie rod extended mountsare shown on pages 30 and 31.12
MOUNTING INFORMATIONPivoted Centreline MountsIf the machine member moved by thepiston rod travels in a curvilinear path, apivot mount cylinder is the obviouschoice. Pivot mounts are available withthe pivot points at the head (TF Mount),at the cap (TR, & C Mounts), or centrallylocated at some position between thehead and the cap (T Mount). In mostcases, a layout of the rod end path willdetermine the best pivot mounting styleto be used. In general, pivot mountedcylinders with the pivot points near thehead (TF and T Mounts ) can use smallerdiameter rods without the danger ofbuckling than similar cylinders with thepivot points at the cap. This can beverified by consulting our columnstrength chart on page 15.Trunnion Front Style TFTrunnion Front Style TRThere are times when a fixed mountingstyle might be indicated by an applicationbut a pivot mount is selected tocompensate for any misalignment thatmight occur - if the misalignment is inone plane. Where misalignment canoccur in multiple planes, the cylindershould be equipped with UNILIGNacessories (see page 8) or with SphericalBearings (see page 15).Trunnion MountsPillow blocks of ample size and rigidityshould be provided and should bemounted as close to the head (or cap) aspossible. Bearing should be provided forthe full length of the trunnion pin. Pinsare intended for shear loads only, notbending loads. SELF-ALIGNING MOUNTSshould NOT BE USED TO SUPPORT THETRUNNIONS SINCE BENDING FORCESCAN ALSO BE SET UP (See Fig. C).Lubrication should be provided tothe pins.An intermediate trunnion (T Mount) can belocated at any position between the headand cap (within limitations) at the time ofcylinder manufacture, but cannot be easilychanged once produced. The trunnionlocation (dimension Xl) must be specifie don the order. See pages 26 and 27 f o rtrunnion mount dimensions.Intermediate Trunnion Style TClevis MountAll Clevis Mount cylinders need provisionon both ends for pivoting in onedirection. A clevis pin of proper lengthand of sufficient diameter to withstandthe maximum shear load generated bythe cylinder at rated operating pressure isprovided. Should a rod end accessorysuch as a rod eye or rod clevis (seepages 7 and 8) be desired, select onewith a pin size (or pin hole) with thesame diameter as the clevis pin. You canthen specify a rod end thread to matchthe accessory.Selecting the accessory on the basis of therod end thread normally supplied canresult in an expensive and unsightly missmatch,especially when the cylinder has alarge oversize or 2:1 diameter rod. Clevismount cylinder dimensions are given onpages 28 and 29.Clevis Style CFixed Non-Centreline MountsCylinders with non-centreline styles ofmounts tend to sway when under load.Relatively short fixed, non-centrelinemounted cylinders can subject mountingbolts to large tension forces which, whencombined with shear forces, can overstress standard bolts. High tensile capscrews are recommended. See Fig. D.Fixed mounted cylinders should be held inplace by keying or pinning. Cylinders withintegral key mounts may be used where akeyway can be milled in a machinemember (see page 15). This type ofarrangement takes up shear loads andprovides accurate alignment of thecylinder. Shear keys should be placed atthe proper end of the cylinder: at thehead, if major loads are in thrust or at thecap if major loads are in tension. See Fig. F.Fig. EFig. FOnly one end of the cylinder should bekeyed. Dowel pins can be used instead ofkeys to help take shear loads and toobtain alignment. The side lug mount hasroom for dowel pins in the lugs. Cylindersmay be pinned together at either end butNOT AT BOTH ENDS.It should be noted that the Foot BracketMount (Style FB), which is not illustratedon this page, should not be used withpressures in excess of 1000 psi.Dimensions for SL and EL Mounts aregiven on pages 24 and 25. FB and SFMounts dimensions can be found onpages 28 and 29.Side Lug Style SLEnd Lug Style ELSide Flush Style SFFig. CFig. DThe rigidity of the machine frame shouldbe considered when using cylinders witha non-centreline mount since strongermachine members are often required toresist bending moments. See Fig. E.13
Page 3: CONSTRUCTION1Offers much longer fat
Page 8 and 9: MOUNTING ACCESSORIESSteel Rod Clevi
Page 10 and 11: THEORETICAL FORCES DEVELOPED BY CYL
Page 14 and 15: PORTING AND AIR BLEEDS1 2 3 4 5Bore
Page 16 and 17: LONG STROKE CYLINDERSStroke Limitat
Page 18 and 19: 18STOP TUBE AND DUAL PISTON Dual pi
Page 20 and 21: FRONT FLANGEMountingsFront Flange M
Page 22 and 23: REAR FLANGEMountingsRear Flange Mou
Page 24 and 25: LUG MOUNTINGSSide Lug Mount - Style
Page 26 and 27: TRUNNION MOUNTINGSTrunnion Front Mo
Page 28 and 29: CLEVIS, SIDE FLUSH AND FOOT BRACKET
Page 30 and 31: TIE ROD AND DOUBLE RODMountingsTie
Page 32 and 33: INSTALLATION AND MAINTENANCEStorage
Page 34 and 35: INSTALLATION AND MAINTENANCERod Gla
Page 36 and 37: PARTS LISTFront Flange MountsRear F
Page 38 and 39: MODEL NUMBERComposition2 1 /2 HH FH
Page 40: 40NOTES

Hydraulic cylinder Tie Rod Design - imperial - Duncan Rogers

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