FASTENING DEVICE FOR ACTUATING CYLINDERS

Abstract: A fastening device for actuating cylinders with longitudinal stringers (2, 3) extending axially along a cylinder tube (1). A fastening yoke, e.g. comprising two halves (6a, 6b), is clampable with the aid of at least one clamping screw (8r) for fixing it in a desired axial position along the cylinder tube. In accordance with the invention the opposing clamping portions (6ar, 6br) of the fastening yoke act on two intermediate clamping blocks (10ar, 10b) which are thus pivoted in opposite directions, so that clamping is achieved exclusively against the inner and outer side portions (2i, 2y and 3i, 3y), whereby internal deformation of the cylinder tube (1) is prevented.

Description: FASTENING DEVICE FOR ACTUATING CYLINDERS. The invention relates to a fastening device for actuating cylinders, provided with at least two stringers situated at maximum of 90° from each other in a circumferential dirβcti-o including a fastening yoke, circumferentially surrounding th cylinder tube of the actuating cylinder and having at least opposing clamping portions, which can be pulled together wit the aid of a clamping screw for clamping the fastening yoke desired axial position along the cylinder tube. The fastening device is intended to be used for actuating cylinders provided with stringers of the form of tie rods extending externally to the cylinder tube and keeping togeth the end walls of the cylinder tube, as well as for actuating cylinders provided with stringers comprising longitudinal be formed integrally with the cylinder tube. A problem occuring in the use of fastening yokes which are clamped circumferentially round the cylinder tube is that it requires a large clamping force for securely maintaining the yoke in the set axial position along the cylinder tube, re¬ sulting m that the clamping action against the outside of t cylinder tube which occurs when the device is fastened in pl causes deformation of the cross-sectional configuration of t cylinder tube. Such a deformation may in turn cause the pist to stick or even get locked in the cylinder bore. The object of the invention is to solve this problem, and th enable secure fastening of the fastening yoke without accomp ing deformation of the cylinder tube, particularly with resp to the internal cylindrical surface of the tube. Further obj are to achieve this with a simple and easily handled device while avoiding engagement with sharp means which can give permanent deformations in the mating surfaces in question. Accordingly, the device shall allow repeated fastening in desired axial positions, i.e. continuously along the entire cylinder tube and not only in certain, specific positions. 5 These objects are achieved by a fastening device having the characterizing features disclosed in the characterizing portion of claim 1. The fastening yoke is thus clamped exclusively against the 10 stringers, and can consequently not exert any notable clamping force on the cylinder tube. The clamping forces are instead applied to the "outer" and "inner" side portions of the stringers. The terms "outer" and "inner" are here used in relation to the dimension in the circumferential direction in 15 the region for an associated clamping screw, e.g approximately to the linear extension of the clamping screw between the opposing clamping portions of the fastening yoke. In the case where the stringers are beads integral with the cylinder tube, this means that the clamping forces are applied substantially 20 the circumferential direction from opposing directions towards the respective bead, and thus the clamping forces substantiall counteract each other. If, as disclosed in claim 7, the opposi clamping surfaces are mutually parallel, there is not obtained any radial force resultant either. 25 An essential aspect of the invention is that the clamping scre can be tightened with a large force without both associated stringers (i.g. tie rods or longitudinal beads) being subjecte to a corresponding force pulling them together which would 30 deform the cylinder tube. This force is instead taken up by th clamping blocks inserted between the clamping portions of the fastening yoke, these block being stressed in the opposite direction to the inner side portion of the respective stringer With the fastening device m accordance with the invention, t clamping forces can therefore be applied exclusively to the stringers, without the cylinder tube itself and its internal cylindrical surface being subjected to any substantial force effect as a result of tightening the clamping screw. As disclosed in claim 2, the clamping blocks are suitably pivotably mounted for pivoting m opposing directions. The movement towards each other of the clamping portions can thus easily converted to a parting movement with accompanying coun directed clamping force action on both the stringers in a pai Further advantageous characterizing features are disclosed in the sub-claims 3 - 10 and will be apparent from the detailed description of the invention given below. The invention will now be described in greater detail with reference to the accompanying drawings, which illustrate some preferred embodiments. Fig. 1 schematically illustrates in a perspective view an actuating cylinder (associated end walls, pressurized medium hoses and piston are not shown) with a fastening yoke in accordance with the invention mounted on the cylinder tube; Fig. 2 illustrates to a larger scale a detail from Fig. 1, namely a pair of clamping blocks inserted between the opposin clamping portions of the fastening yoke; Fig. 3 is a cross-section through the cylinder tube and fastening yoke according to Fig. 1; and Fig. 4 is a cross-section of a modified embodiment of the fastening device for an actuating cylinder with tie rods. In the embodiment according to Figs. 1 - 3, the actuating cylinder tube 1 is provided with beads 2,3,4,5 formed integral therewith and extending mutally parallel axially along the cylinder tube. The beads are arranged in pairs such that those in a pair, e.g beads 2,3 and beads 4,5 are at an angular distance CX from each other in a circumferen ial direction, whe (X is a maximum of 90°, and in the illustrated case about 45°. Each bead has an axial, through bore, which can be utilized at the ends of the cylinder tubes for fixing the end walls, e.g with the aid of fastening screws. Alternatively, tie rods can be inserted in these holes, provided that the rods can be pre- streεsed with sufficient tensional force to take up the separating forces on the end walls caused by the pressurized medium. A fastening yoke 6 comprising two halves 6a, 6b surrounds the cylinder tube 1 without touching its outside, except in the ar of the beads 2 - 5 (see Fig. 3), and can be clamped in any desirable axial position along the cylinder tube by clamping action exerted exclusively against the side portion of the beads. In the illustrated example, the halves 6a, 6b each has a stub journal 7a, 7b for mounting the actuating cylinder so tha it is fixed at the journals, possibly for pivoting about these journals . The halves 6a, 6b are clamped with the aid of two pairs of clamping screws 8r,9r and 81,91. One end of the halves is pull together by the first pair of screws 8r,9r (to the right in Figs. 1 - 3), these forming clamping portions 6ar,6br, while t other end of the halves (see Fig. 3) forming clamping portions 6al,6bl are pulled together with the aid of the second pair of clamping screws 81,91 (to the left in Figs. 1 - 3). Pairs of clamping blocks 10ar,10br and 10al,10bl are inserted between opposing clamping portions 6ar,6br and 6al, 6bl , respectively, the respective clamping screw extending freely through registering holes in the respective clamping portion.Bar and (where the screw head engages against the outside) and in bo clamping blocks in the respective pair and being in threaded engagement with an internal thread in the other, opposing clamping portion 6br or 6al, respectively. In the embodiment according to Fig. 1 - 3, both clamping blo in a pair (10ar,10br or 10al,10bl) engage each other in.an engagement region 11 situated radially inside the associated clamping screw, said region forming a pivotal center for the clamping blocks when the screws are tightened and the respec clamping portion (see particularly Fig. 2 with the clamping portion 6ar,6br and the clamping blocks 10ar,10br) is tighte against the radially outer corner edge 12 on the outside of respective clamping block. The clamping blocks in a pair, e. 10ar,10br are thus caused to pivot in opposite directions wit mutal engagement in the region 11 so that the radially inmost corner edge portions 13 are urged under clamping action towar the inner side portions 2i,3i of the respective bead 2,3. The respective clamping portion of the halves 6a, 6b simultaneousl abut against the outer side portion 2y,3y (see Fig. 3) of the respective bead 2,3. The opposite side portions 2i,2y; 3i,3y the respective bead 2,3 form parallel engagement surfaces, th clamping forces thus completely counteracting each other with further force resultant occuring, which could deform the cylinder tube 1. As will be seen, the fastening yoke halves 6a, 6b are dimensioned such that they do not touch the cylinde tube 1 except at the opposing side portions of the beads. A condition for achieving this desired pivoting movement of t clamping blocks, and accompanying clamping action against the inner side portions of the beads is that the pivotal center ( engagement region 11) is located, in a radial direction, betw the regions 12,13, where the clamping blocks are urged agains the clamping portions and the beads. Accordingly, the clamping blocks in a pair have on the one hand mutually opposing, conve surfaces formed for line or spot engagement in the region 11, suitably radially inside the associated clamping screw, and on the other hand surfaces facing away from each other which are formed for engagement against the clamping portions (at 12) of the fastening yoke, radially outside the pivoting center, as well as surfaces for engaging against the inner side portions (at 13) of the beads radially inside the pivotal center. For obtaining effective clamping action and good retaining force, the clamping blocks have their surfaces facing away fro each other suitably formed for spot or line engagement both against the clamping portions (at 12) of the fastening yoke an the inner side portions (at 13) of the beads. By "spot or line engagement" is intended here engagement in a limited surface area, which in practice can be a small surface area about a point or a relatively narrow surface area along a line. To obtain the best possible friction and thus the best possibl fixation against axial displacement, it is further advantageou either during manufacture or afterwards, to make the radially inward engagement surfaces (at 13) of the clamping portions and/or the clamping blocks rough, e.g. raw or knurled, so that a rough surface structure and effective friction action are obtained . The geometry, of the clamping blocks 10ar,10br etc can of cours be modified, although preferably in such a way that the above described pivotability about the pivotal center (between the engagement regions 12 and 13) is retained. Alternatively, it i principly possible to allow the clamping blocks to be translat in opposite directions into engagement with the inner side portions of the beads, e.g. with the intermediary of a mechani al transmission acting between the clamping portions and the clamping blocks. The illustrated embodiment is however extreme simple, cheap in manufacture and easy to assemble and use, the mutually opposing surfaces of the blocks having on either side (radially) of the engagement region 11 planar surface portions (see Fig. 2) and similarly planar surface portions on the surfaces facing away from each other which are parallel to the planar, mutually opposing surfaces. As will be seen from Fig. 4, the fastening device in accordanc with the invention can also be used in actuating cylinders having stringers in the form of tie rods 2', 3', 4', 5', which ke the ends of the cylinder tube together and extend axially alon the cylinder tube 1' spaced radially from the tube and (in the illustrated example) distributed at equal angular spacing (90° in a circumferential direction. In a way corresponding with the above described embodiment, tw fastening yoke halves 6'a and 6'b are clamped with the aid of clamping screws B'a.θ'l, pivotable clamping blocks 10 'ar , 10 'br 10'al,10'bl are acted on by the clamping portions 6'ar,6'br; 5'al,6'bl for engaging against the inner side portions of the tie rods, simultaneously as the clamping portions engage again the opposing outer side portions of the tie rods. In this case the clamping blocks are provided with a radially inward, cir¬ cumferentially extending engagement tongue 14, which is urged against a radially more inward side portion of the associated tie rod (which has a circular cross-section in the illustrated example) . The clamping portions 6'ar, etc are here urged again two radially outwardly situated parts of the outer side portio of the tie rods. Clamping action is thus exercised on three linear engagement surface portions, the clamping thus being very stable and secure without any force acting on the cylinde tube 1' . In the embodiment according to Fig. 4, the clamping blocks engage with their mutually opposing surfaces against an intermediate spacer 15r,151 in the respective pair, the pivota center 11' in this case also lying radially between the outer engagement regions, where the respective clamping block engage against the clamping portion and the tie rod, respectively. The clamping blocks 10'ar, etc and the spacers 15r,151 are kep constantly in place by the clamping screws 8 'r , 8' 1 going throu holes therein placed directly opposite each other. It is also possible to allow outer clamping blocks (not shown) to act against the outer side portions of the stringers (the t rods or beads) . For the remainder, one skilled in the art can modify the fastening device in accordance with the invention within the scope of the following claims. For example, the clamping screws do not need to extend through holes in the clamping blocks, and the latter can be placed between two c1amping screws .

Claims: CLAIMS 1. Fastening device for actuating cylinders, provided with least two stringers (2-5;2'-5') situated at a maximum of 90° from each other in a circumferential direction, including a fastening yoke (6 , 6b; 6 ' , 6 'b) , circumferentially surroundin the cylinder tube (1;1') of the actuating cylinder and havin least two opposing clamping portions (6a , 6br ; 6 'ar , 6 'br) , wh can be pulled together with the aid of a clamping screw (8r; for clamping the fastening yoke in a desired axial position along the cylinder tube, c h a r a c t e r i z e d in that clamping portions of the fastening yoke are arranged such th when the clamping screws are tightened they engage against an outer side portion of each stringer (2y,3y), simultaneously a pair of clamping blocks (10ar,10br; 10'ar,10'br) movably mou between the opposing clamping portions of the fastening yoke caused to be urged against an opposing, inner side portion (2i,3i) of each stringer (2,3) and in that the fastening yoke (6 , 6b; 6 'a , 6 'b) is dimensioned such that in the clamped posit it extends round the cylinder tube (1;1') without clamping action against the tube, whereby internal deformation of the cylinder tube is prevented. 2. Fastening device as claimed in claim 1, c h a r a c - t e r i z e d in that the clamping blocks (10ar,10br) in a p are pivotably mounted for pivoting in opposite directions. 3. Fastening device as claimed in claim 2, c h a r a c t e i z e in that the clamping blocks in a pair have coaxial through holes for free passage of the associated clamping scr the coaxial through holes permitting mutual pivoting of the clamping blocks. 4. Fastening device as claimed in 2 or 3, c h a r a c t e r i z e d in that both clamping blocks ( 1Oar , lObr; 10 'ar, 10 'br) mutually engage each other (11) or engage against an inter¬ mediate spacer (15r,151) . 5. Fastening device as claimed in any one of claims 2 - 4, c h a r a c t e r i z e d in that the clamping blocks in a pai have on the one hand surfaces facing towards each other formed for line or spot engagement in an engagement region (11,11') formed as a pivotal center, suitably radially inside the associated clamping screw, and on the other hand surfaces facin away from each other formed for engagement (12) against clampin portions of the fastening yoke radially outside said pivoting center (11), and also for engagement (13) against said inner side portion of each stringer radially inside said pivotal center . 6. Fastening device as claimed in claim 5, c h a r a c t e r i z e d in that the clamping blocks (10ar,10br) have their surfaces facing away from each other formed for line or spot engagement both against the clamping portions of the fastening yoke (at 12) and against the stringers (at 13). 7. Fastening device as claimed in any one of the preceding claims, wherein that the stringers comprise beads (2 - 5) formed integral with the cylinder tube (1), c h a r a c t e r i z e d in that said inner and outer side portions of the respective bead include substantially parallel engagement surfaces (2i,2y). 8. Fastening device as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the radially inwa engagement surfaces of the clamping portions and/or the clampi blocks have a rough surface structure. 9. Fastening device as claimed in any one of the preceding claims, wherein the fastening yoke comprises two halves (6a, 6 c h a r a c t e r i z e d in that the halves have at least first clamping screw (8r,9r) for pulling together said clampi portions (6ar, 6br9 of one end of the halves while acting on a associated first pair of clamping blocks (10ar,10br), and at least one other clamping screw (81,91) for pulling together t clamping portions (6al,6bl) at the other end of the halves wh acting on the associated second pair of clamping blocks (lOal.lObl), said first and second pairs of clamping blocks being urged against their respective axially extending string (2,3 and 4,5) . 10. Fastening device as claimed in claim 9, the stringers comprising beads formed integral with the cylinder tube, c h a r a c t e r i z e d in that the Beads (2 - 5) have ax bores for fixation of the end walls of the actuating cylinder with the aid of end wall fastening screws or tie rods accommodated in the bores .

Inventors: PIRHARDI EBRAHIM, PIRHARDI, EBRAHIM
Applicants: MECMAN AB, AB MECMAN
Application year: 1990
Main classification: F16J10
IPC codes: F15B15, F16J10