TANGENTIAL GRINDING MACHINE

Abstract: A tangential grinding machine characterised by being provided with at least one grinding device (7) comprising: a rotary member (20), a plurality of abrasive sectors (40) mounted on supports (27) radially mobile on said rotary member (20), and members (23) for radially shifting said supports (27) in order to cause said abrasive sectors (40) to move outwards by an amount suitable for compensating their wear.

Description: TANGENTIAL GRINDING MACHINE This invention relates to a tangential grindin machines . Tangential grinding machines are known comprising grinding device consisting essentially of a grinding wheel o abrasive material which when rotated removes by abrasion oarr of " e material with which it com.es inio contact. Currently known grinding machines comprise either fixed structure and means for feeding the workpiece toward the abrasive grinding wheel, or an abrasive grinding whee support structure mobile along the workpiece which is fixed The particular application and the specific requirements o the workpiece determine the use of one or other type o machine. if for example a rolled section leaving a rollin mill is to be ground, the machine will obviously be of th fixed type, whereas if for example an alrealdy laid railwa rail is to be ground, the machine will obviously be of th mobile type. However, independently of the type of structure used the known grinding devices, ie the assembly consisting of th abrasive tool or tools, its or their rotary drives adjustment and replacement systems and all other accessor members required for correct operation, they currently suffe a series of limitations and drawbacks which the presen invention proposes to obviate. One of these drawbacks is that each grinding wheel generally consists of a disc of abrasive material and is intended to grind with its circumferential surface at a peripheral speed within a precise and narrow range of values. As the grinding wheel wears with time, and thus its grinding circumference decreases, it is necessary on the one hand to increase its angular speed and on the other hand to shift its axis of rotation with respect to the workpiece, so as to always ensure mutual contact. In all cases, complicated adjustment and control equipment are required, but this does not obviate the need to replace the grinding wheel very frequently, ie while the amount of abrasive material still unused is considerable. A further drawback of known grinding devices is that in the course of time the grinding wheel wears τo the shape of the workpiece. If for example the workpiece is a rail which v/ith use undergoes deformation of its transverse profile, the wear of the grinding wheel "follows" this deformation, and the grinding wheel wears in a non-uniform manner. It is consequently necessary to periodically halt the machining and to restore the transverse profile ot the grinding wheel by means of a suitable profiling tool. This results in frequent stoppage of machining, a lengthening of the machining time rapid grinding wheel wear, and unsatisfactory grindin because of the different abrasive action produced before an after restoring the wheel profile. A further drawback is that current grinding wheels hav necessary to be below a certain size, in order for obviou safety reasons to limit the danger of "explosion" as a resul of the many stresses to which they are subjected durin machining. Thus to attain the required peripheral machinin speed, a fairly high rotational speed is required, requirin suitable dimensioning of the entire structure, in particula of the moving members. A further drawback of known grinding devices is that an overloading of the grinding wheel, due for example t excessive interference with the workpiece or to excessiv pressure under which the grinding wheel is thrust against th workpiece, can result in very serious consequences for th entire machine because of the "rigidity" of the system, whic is incapable of absorbing such abnormal stresses and ca become jammed without warning. A further drawback of known grinding devices is th difficulty of estimating the amount of grinding done, and i any event a considerable lack of precision in this estimation. In other words, known grinding machines are able to measure the amount of accomplished grinding only by indirect measurements and by comparison between the situation before and after machining. In the case for example to restoring longitudinal planarity to a rail, the only means of checking the e ec iveness and correctness of the machining Is to pass suitable apparatus for measuring waviness over the ground rail, and then repeat the grinding operation if the number and type of undulations are outside a predetermined range of values. In addition to all the a oresaid drawbacks, which relate to the grinding device of any tangential grinding machine, there are also particular drawbacks encountered in grinding machines used specifically for rail profile restoration in railways, tramways and/or underground railways. One of these drawbacks is that known rail grinding machines generally use cup grinding wheels, which operate along a narrow longitudinal strip of the rails to be ground. A large number of grinding wheels are therefore required, and as these are mounted on trolleys a large number of these latter are necessary for grinding the adjacent strips which together make up the entire rail profile. The result is an overall space requirement which is often unacceptable, and an - -> - imperfect grinding result because of the inevitable rai faceting which appears on termination of the work. I addition, those cup grinding wheels which grind the rai lateral surfaces are impeded by the presence of natura obstacles such as points, guide and retaining plates at th points and, in the particular case of tramlines, the cemen and asphait and also the actual counterweb of the rai itself. A further drawback of known grinding machines with cu grinding wheels is that said grinding wheels, which bot grind the rails and create the reference plane at one and th same time, are consumable elements and as such they chang with time and are unsuitable for forming a proper referenc plane. This drawback, which in the case of short longitudina rail undulations (up to 30 cm) can be overcome by the actua dimensions of the cup grinding wheels themselves (which ca have a diameter of up to 30 cm), becomes more apparent i lengthy longidudinal undulations, which cannot be covered b the cup grinding wheel dimensions. A further drawback of known rail grinding machines i that the cup grinding wheels must generally operat simultaneously on both rails for mass balancing reasons. Thi makes it more difficult to grind a single rail, such as th central earth rail or outer side feed rail of undergroun railways. In addition, when these grinding machines operat simultaneous!;/ on both rails, the abrasion effect i substantially identical in both. Although this is no proble along straight lengths in which the rail deformation I substantially equal in both, it becomes a problem whe grinding curved lengths, in which the inner rail is mor loaded and thus more deformed. In such a case, the unifor grinding action on both rails means that more material i ground away from the outer rail (less de ormed) than i strictly necessary for Its correct restoration. A further drawback of known grinding machines is that a the individual grinding wheels operate on different surfac lying at various angles, they cause sparks to shoo practically in all directions, without it being possible t control or contain them. All these drawbacks are obviated according to th invention by a tangential grinding machines, characterised b comprising: - a rotary member, - a plurality of abrasive sectors mounted on support radially mobile on said rotary member, and - members for radially shifting said supports in order t cause said abrasive sectors to move outwards by an amoun suitable for co pesating their wear. A preferred embodiment of the present invention i description in detail hereinafter with reference to th accompanying drawings, in which: Figure 1 is a diagrammatic side view of a machine accordin to the invention; Figure 2 is a plan view thereof; Figure 3 is a front view thereof; Figure 4 is an enlarged detailed view of the grinding devic and underlying roller assembly, taken in the sam direction as Figure 1 ; Figure 5 is a vertical sectional view thereof taken on th line v-V of Figure 4; Figure 6 is a partly perspective and partly sectional vi thereof; Figure 7 is an enlarged partial side view thereof; Figure 8 is a diagrammatic detailed view of two variousl inclined grinding devices operating on the sam rail; Figure 9 is a diagrammatic detailed front view of th finishing unit; is a diagrammatic side viev of the machi according to the invention coupled to a conveyin locomotive; and Figure 11 shows the machine in the same view as Figure 1 during operation. As can be seen from the figures, the grinding machine according to the invention comprises a framework 1 mounted on wheels 2 which run on rails 3. On the f amework 1 there are mounted two transverse guide beams 4 for wwheeis 5 provided in a mobile structure 6. The mobile structure 6 comprises a grinding device indicated overall by 7 and described in detail hereinafter, and a supporting roller assembly 8. More specifically, the mobile structure 6 comprises a lower frame 9 which, when the transverse position of the structure 6 along the beams 4 has been chosen, can be locked in that position by any conventional system, and an uppse«r frame 10 connected to the lower frame 9 by a parallelogram system of articulated levers. The upper f ame 10 supports a saddle 11 which is hinged at one end to the frame by a shaft 12 which allows slight axial play, and is hinged at its other end to the same frame by a reduction member 13 which enables it to be adjuste vertically. The connection between the reduction member - 3 and upper frame 10 is of articulated type, and as in the case of the shaft 12 allows a limited axial play in order, as wi be seen hereinafter, to ensure correct lateral adaptation the grinding device 7 to the rail to be ground even wh inevitable gauge variations exist. The saddle 11 supports t grinding device 7, while the frame 10, which supports t saddle 1 i . rests on the roller assembly 8 in corresponden with a hinging shaft 14. The roller assembly 8. comprises a pair of longitudin bars 15, between which a plurality of idle rollers 16 a positioned. The roller assembly 8 comprises a pair of longitudin bars 15, between which a plurality of idle rollers 16 a positioned. The length of the bars 1 and thus of the rolle assembly 8 depends on the particular working requirements Thus in the case of rails for railway trains, which requir considerable rail planarity as they operate at high speed the roller assembly 8 is made longer even though this result in a larger quantity of material removed during grinding whereas in the case of rails for -trams and undergroun trains, which can accept slight longitudinal undulation a they operate at a much lower speed, the roller assembly 8 ca be shorter and thus limit the quantity of material remove during grinding. The roller 16 are positioned in the two end portions o the roller assembly 8, so as to leave a central free regio for passage of the rotary member of the grinding device 7, a described hereinafter. The upper rame 10 is moved relative to the lower f a 9 of the mobile structure 6 by hydraulic or pneumati cylinder-piston units 17 interposed between the two. The saddle 11 is also provided with a plurality of guid rollers 18 which extend laterally beyond the rollers 16 an adhere to one of the two sides of the rail to be ground. The are urged against this latter by a pneumatic cylinder-pisto unit 19 interposed between the saddle 11 and framework 1. The grinding device 7 mounted on the saddle 11 comprise a cylindrical steel casing 20 with a removable front cove 20'. It is fixed on a shaft 21 supported at its ends by pair of ball bearings 22 fixed to the saddle T1, and i rotated by an electric motor 62. Within the casing 20 there is provided an external rin gear 23 mounted on the shaft 21 but free to rotate about It in that front surface facing the rear wall 24 of the casin 20, the ring gear 23 is provided with a spiral groove 25 o constant pitch In which there engage teeth 26 provided in si slides 27 disposed 60x apart and slidable along radial slot 27' formed in said rear wall 2-. Each slide 27 is retained in the respective guide slo 27' by a pair of metal fillets 28 applied externally to th rear wall 24 ana engaged in longitudinal grooves 29 forme laterally in each slide 27. A clamp 30 carrying the abrasive material is applied t the outer end of each slide 27. Specifically, a plate 3 forming the support for the clamp 30 is fixed to each slid 27 by a pair of keys 31 and screws 32. This plate, which ha the approximate shape of a circular sector, comprises, nea its curved edge two outer bores and an outwardly open centra recess 34. The two outer bores house two correspondin articulation pins 35 for bar 36 to which the clamp 30 i articulated which remains centered with respect to the plat 33 due to the presence of suitable spacers 37- Two threade pins 38 are housed in and pass through the central recess 3 and are engaged by nuts 39 to tighten the two jaws of th clamp 30 against an abrasive sector 40. The bore by which the connecting bars 36 are pivotall mouned on the pin 35 is of slotted type to allow the entire clamp 30 to undergo inward radial movements, as will b apparent hereinafter. The inner Derimetral zone of the casing 20 houses thre gear wheels disposed 1 0 apart and engaged with the ring gear 23. The shaft 42 of each gear wheel 41 is supported o the two facing walls of the casing 20 by bushes 43.43', an extends beyond the cover 20' in the form of a portion whic is coupled by means of free-wheel device 44 to the end of a operating lever 45 , the other end of which is connected to pneumatic piston 46. This is fed by an external compresso 63, by way of a rotary connector 47 and a duct 48 forme within the shaft 21. Three supports 49 for three contact sensors 50 ar fitted 20x apart on the outer cylindrical surface of th casing 20 in the interspaces between adjacent abrasiv sectors 40 and operate in three different planes orthogona to the axis of the shaft 21. The sensors 50 are connected, through ducts formed within the shaft 21, to a slip-rin assembly 51 for externally transferring the signals. A electronic circuit board receives the signals collected b the slip—ring assembly 51 and controls a solenoid valve (no shown on the drawings ) which regulates the compressed ai feed into the duct 48. The grinding device 7 also comprises a profiling rolle 53 applied to the saddle 11 and facing the abrasive element 40 In a position diametrically opposite the zone of contac with the rail 59 to be ground. In addition to the grinding device 7, the construction details of which have been described heretofore, there also mounted in the grinding machine framework 1 a finishi 5 unit indicated overall by 54. It comprises its own structu 55 in which a drive roller 56 is mounted together with plurality of idle rollers 57, and about which an abrasi band 58 extends disposed in a plane orthogonal to th longitudinal axis of the rail 59 to be ground. A plate 6 o shaped to correspond to the upper profile of the rail 59 i kept forcibly adhering to this latter by a pneumatic syste 61. Preferably, the position of the finishing unit 54 i adjustable transversely relative to the framework 1 , so as t be able to operate on the chosen rail, and in this case guid 5 rails 64 are associated with the plate 60 to adhere to th lateral surfaces of the rail 59 to be ground, and thus ensur centering of the plate with respect to the upper- profil thereof. Finally, the grinding machine according to the inventio 0 comprises other accessories such as the operator's drivin position, a variable speed motor for advancing the machin during the grinding work, an operating and control panel fo the various operating stages, and anything else which coul be considered useful in practice for Implementing the work under the most effective operating conditions. In the description of operation of the grinding machine according to the Invention given hereinafter, the method of operating the overall machine is kept separate for reasons of clarity from the method of operating the grinding device, which represents its basic element. In operating the machine, It must firstly be transferred to the position in which the rail 59 to be ground is located. This transfer is preferably done with a locomotive, which ca also be provided with a generating unit for self-containe electrical powering of the grinding machine, especially if the track to be ground is not electrified or if th electricity supply has been temporarily suspended during th maintenance work. It is also possible to provide a generato unit mounted on the framework 1 itself, although it is preferable to use electricity fed either through a suppl cable from a fixed socket, or a generator unit mounted on a auxiliary truck and, especially during tunnel work, kept reasonable distance from the machine according to th invention essentially for contamination reasons. In an event, it is advisable to provide a cable winder 65 withi the framework 1. When the grinding machine has been transferred to it working position, it must be set up for correct operation. T do this, a profiling roller 53 corresponding to the shape o the rail 59 to be ground must firstly be mounted, and th mobile structure 6 must be correctly positioned along th beams 4. Then, in relation to the type and extent deformation of the rail to be ground, the plane in which th roller assembly 8 rests on the rail itself is defined. I this respect, as the upper surface of this rail is generall different from the level at which th machine slides on it own guide rails, it is necessary to lower the frame 10, whic during transfer had been kept raised, towards the rail 59 t be ground, until the roller assembly 8 rests on it. The subsequent adjustment relates to the degree o interference of the grinding device 7 with the resting plan of the roller assembly 8. The extent to which the variou rotating abrasive sectors 40 project, and thus the extent o removal of ferrous material, depends on the degree o deformation of the rails and on the set degree o interference. In all cases, the interference is adjusted b operating the reduction unit 13. The three sensors 50 are then positioned so as t ope a on the ideal ' τ rιπdi. rr circumference ie in th external position reached under centrifugal action by the clamps 30 connected to the respective supports 33. Finally, the sasddle 11 is slightly rotated about longitudinal axis to slightly Incline the axis of the grinding device 7 to the plane on which the frmaework 1 rests on the rails 2, in order to adapt the plane of rotation of the grinding device to the longitudinal plane of the rail to be ground, this plane being slightly inclined in know manner. At this point the machine is ready to operate. The variable speed motore is powered to advance the machine alon the rails, and at the same time power is also supplied to th motor which rotates the grinding device 7 and, if required, to the motor coupled to the driving roller 56 of th finishing unit 54, which had been previously positioned t correspond to the rail 59 to be ground. This rail ca obviously be either one of the two rails forming the track o the central earth rail or lateral electricity supply rail. When the shaft 21 is rotated, it rotates the casing 2 and hus the slides 27, the supports 33, the clamps 30 and the abrasive sectors 40, which become disposed in their oute radial position by centrifugal force. As the disc 20 rotates, the grinding machine advances and the rail 59 is ground t correspond to the transverse profile of the abrasive sector 4G. However, as this abrasive action results not only in th removal of part of the constituent material of the rail 5 but also wear of the abrasive sectors 40, after a certai time the sensors 50, which at the commencement had been se with their end on the original grinding surface of th abrasive sectors 40, now project beyond this surface and com into contact with the rail 59 to be ground. A signa generated by this contact is received by the electroni circuit 52 which controls the pulsed feed of compressed ai through the connector 48, to thus operate the three piston 46. Each piston 46 in its turn operates the relative leve 45 , which induces a small rotation of the correspondin gearwheel 41. This rotation, which is common to the thre gearwheels, results in a corresponding rotation of the rin gear 23, which because of the engagement between its spira groove 25 and the slides 27, causes these latter to mov slightly outwards simultaneously in order to restore th original abrasion surface which, by removing the materia from the rail to be ground, prevents operation of the sensor 50. Basically, the device according to che invention enable grinding of the rail to be carried out while maintaining substantially costant diameter of the active abrasion surface. However the aforegoing, while being rigorously correct from the theoretical viewpoint, has certain practical limits. in this respect, besides undergoing longitudinal deformation (waviness) determined by Its construction, its laying and its use, a rail also undergoes transverse deformation, shown in Figure 4 in which the continuous line indicates the original • transverse profile of the rail and the dashed line indicates its deformed profile (exaggerated). In this case although- the grinding action on the one hand leads to the abrasion of th rail, on the other hand it results in non-uniform wear of th abrasive sectors 40, with the result that after a certai time, the transverse profile would remain at least partiall deformed even after grinding. In order to automatically resolve this problem, th profiling roller 53 is provided. For this puprose, it i mounted in a position diametrically opposite the position o contact between the abrasive sectors 40 and the rail 59 an is constructed of diamond-clad material, ie of a materia much harder than the constituent material of the abrasiv elements, its profile corresponding to that of rail 59- Consequently, if the transverse deformation of the section t _ - α _ be ground leads to non-uniform wear ot the abrasive secto 40 of the grinding wheel, the most worn portions uncover t sensors 50, which cause said sectors to move outwards a interfere with the profiling roller 53, so that the original profile is restored. It is therefore apparent th the profiling roller 53 is normally inactive. but that ea time the sensors 50 sense non-uniform wear of tne transver profile of the abrasive sectors 420 they cause it automatically intervene during the operation of the grindi wheel to an extent just sufficient to restore their origin profile. The inevitable gauge differences which during operati arise between the rail 59 to be ground and the advanci machine are overcome on the one hand by the lateral gui rollers 18 against which the support saddle 11 for th grinding device 7 is thrust by the pneumatic cylinder-pisto unit 19, and on the other hand by the axial play between th saddle 11 and the pins 12 and 14 on which it is hinged to th upper frame 10 of the mobile structure 6. If it is required to operate simultaneously on tw rails, the invention provides either for the use of tw machines advancing at equal speed, or for the ..se of a singl machine in which wo r.ceile structures 6 are rr.cnted. If for particular operations the profile of the rail 5 to be ground either cannot be or cannot convenienntly b ground by a set of abrasive sectors mounted on a singl casing 20 (because the accentuated deformation of the profil would lead to considerable non-uniform wear of the abrasiv sectors 40 ) the invention also provides for mounting on single machine, and possibly on the same mobile structure 6, two separate grinding devices, one acting mainly in a inclined plane to remove most of the asymmetric deformatio of the rail 59, and the other acting subsequently in vertical plane to restore the original profile. From the aforegoing it is apparent that the grindin device according to the invention has important advantages b virtue of the new and original operating principle on whic it is based, and in particular: - the circumferential grinding surface is maintained a substantially constant diameter, making it possible to kee the peripheral speed of the abrasive sectors 40 at thei ideal value without having in any way to vary their angula speed and without having to vary the position of their axi of rotation as they become worn, - the abrasive sectors 42 are almost completely utilised with considerable reduction in machining costs, - che transverse profile of zhe abrasive sectors 40 can automatically restored without interrupting machining, a in all cases limiting the quantity of abrasive material be removed from said abrasive sectors to that strict necessary for such restoration, - any risk of "explosion" of the grinding wheel is obviate without any limit to its dimensions, by virtue of i separate-part construction, - improved grinding made possible by the grinding whe construction in the form of sectors 40, which inter al ensure better self-cooling, - improved safety, in that in the case of overloading, t abrasive sector or sectors ' 40 "yield" inwards, s preventing jamming and damage to the machine under abnorm stress, - in case of breakage only the abrasive sector or sector concerned need to be replaced, so reducing the damage whic accidental breakage could cause, and the cost of makin good the equipment, - extremely compact construction which considerably reduce overall dimensions compared with those of conventiona grinding machines, thus making the rail grinding wor easier and quicker, - grinding can be effected either on one rail or on more tha one rail simultaneously, and if only one rail is to b ground only the one machine need be used for the chose rail, - very high quality work by virtue of the absence of eve minimal faceting of the ground rail, - the grinding operation, whicn is it.seif of high qualit -, can be followed by a finishing operation which makes th rail particularly suitable to receive sliding contacts, - grinding can be effected under conditions in whic conventional grinding machines cannot operate because o the presence of obstancles such as points, retaining an guide plates at the points or, in the case of tramlines cement or asphalt, or the counterweb itself, - sparks are not projected in all directions, because th particular grinding device results in the formation of onl a narrow band of sparks substantially limited to th longitudinal direction, of the machine, and thus of n importance during working and in any event easil contained, - during machining, information can be obtained regarding th machining itself and the condition of the workpieces. I this respect, it is clear that for example a regula frequency of signals derivging from the intervention of th sensors 530 distributed along the circum erence of t rotary member together with simultaneous issue of signal deriving from the intervention of any sensors disposed i one and the same radial plane indicate correct operation i that the section being machined is substantiall rectilinear and not transversely deformed. The constancy of the outer grinding diameter and of th transverse profile of the abrasive sectors 40 allows a interesting advantageous application of the device accordin to the invention in checking the longitudinal "planarity" o a ground section. In this respect, as the grinding machine slides alon the actual rails being ground, its operation cannot b influenced by any pre-existing waviness. In other words, a the grindig machine rests the initial undulated longitudina section into a rectilinear longitudinal section. The greate or lesser approximation of the new undulated section to rectilinear section depends on many factors such as th extent of the initial deformation, the number, , type an distance apart of the point at which the grinding machin rests on the rails, the number of passes etc.. By virtue of the substantially constant grindin circumference, the invention allows ingenious application in estimating the degree of longitudinal planarity of a ground rail. For this purpose, the machine is "calibrated" on a test bench in the form of a piece of perfectly straight rail of known length. A grinding machine provided with a grindig device according to the invention Is made to operate on this length of rail, causing the sensors 50 to intervene a nu er of times depending on the length of the piece, the thickness of the material to be ground, the speed of advancement etc.. This numerical value, which corresponds to the number of interventions of the sensors 50 when the device operates o rails under a condition of perfect planarity, can b associated with the grinding device when operating unde these conditions and constitues a lower limiting valu towards which a grinding device tends as it approaches thes ideal conditions. In pratic , by comparing the number o interventions of a machine operating on the deformed rai after correcting to the length of the test bench, with th number of interventions corresponding to the calibrate value, an objective indication is obtained of the extent t which the ground rail differs from conditions of perfec planarity.

Claims: CLAIMS 1. A tangential grinding machine characterised by bein provided with at least one grinding device (7) comprising: - a rotary member (20), - a plurality of abrasive sectors (40) mounted on support ( 27 ) radiallv mobile on said rotary member ( 20 ) , and - members (23) for radially shifting said supports (27) i order to cause said abrasive sectors (40) to move outward by an amount suitable for compensating their wear. 2. A machine as claimed in claim 1, characterised b comprising, for said grinding device (7), a support membe (11 ) which is disposed on a framework (1 ) provided wit wheels (2) and is itself supported by a frame (10) which ca be adjusted in height relative to the framework ( 1 ) and rest on a roller assembly (8) which rests on the profile (59) t be ground. 3. A machine as claimed in claim 2, characterised in tha the roller assembly (8) consists of a pair of " longitudina bars (15) supporting a plurality of rollers (16) o horizontal axis which are located in the outer regions o said bars (15) to define-, a free central region for passage o the rotary member (20) with the abrasive sectors (40) of th grinding device > . ~ ] . - 26 - 4. A machine as claimed In claim 2, characterised in that the grinding device (7) can be adjusted In height relative t the roller assembly (8). 5. A machine as claimed in claim 4, characterised b comprising a framework (1 ) provided with wheels (2), a fram (10) adjustable vertically relative to the framework (1 ) an resting in an articulated manner on the roller assembly (8), and a support member (11 ) or the grinding device (7 ), thi member being adjustable vertically relative to the fram (10). 6. A machine as claimed in claim 2, characterised in tha the position of the frame (10) relative to the framework (1 can be adjusted transversely. 7. A machine as claimed in claim 2, characterised in tha the grinding device support member (11 ) Is provided wit rollers (18) of vertical axis, which adhere laterally to th profile (59) to be ground. 8. A machine as claimed in claim 7, characterised in tha the support member (11 ) or the grinding device (7 ) is mobil transversely to the framework (1 ) and its guide rollers (18 are kept elastically adherinc to a lateral surface of th profile (59) to be ground. 9. A machine as claimed in claim 2, characterised in tha 27 - there is fitted to the framework (1 ) a finishing unit (54 consisting of, disposed in a transverse plane, an endles abrasive band ( 8 ) which is rotated and is arranged such tha a portion thereof adheres to the profile (59) which has jus been ground. 10. A machine as claimed in claim 9, characterised in tha the finishing unit ( 54 ) comprises a plate ( 60 ) shaped t conform to the profile (59) to be ground and kept forcibl adhering to said profile so as to press the interpose abrasive band (58) against it. 11. A machine as claimed in claim 9, characterised in tha the position of the finishing unit (54) can be adjuste transversely relative to the framework (1 ). 12. A machine as claimed in claim 6, characterised b comprising several grinding devices rotating on one and th same structure (6) the position of which can be adjuste transversely relative to the framework (1 ). 13. A machine as claimed in claim 1, characterised in tha the axis of the rotary member ( 20 ) can be inclined to th plane in which the framework (1 ) rests. 14. A machine as claimed in claim 1 , characterised b comprising a plurality of sensors (50) which are activate when a predetermined degree of wear of the abrasive sector - 28 - (40) is reached and which act on the radially shiftin members (23). 1 . A machine as claimed In claim 1, characterised in tha the rotary member (20) consists of a cylindrical casin comprising, in a base (24), a plurality of radial slid guides ( 27 ' ) for the mobile supports (27,33) of the abrasiv sectors (40). 16. A machine as claimed in claim 1, characterised b comprising a disc (23) mounted coaxially on said rotar member (20) and containing at least one spiral groove (25) o constant pitch engageable by teeth (26) provided in th mobile supports (27, 33), with said disc (23) there bein associated means (41-,45,46) to cause it to rotate relative t said rotary member (20 ). 17- A machine as claimed in claim 16, characterised in tha the rotary member (20 ) consists of a hollow cylindrica casing internally housing the disc (23), of which tha surface containing the spiral groove (25 ) aces the circula end wall (24) of said casing, in which the radial guide (27' ) are provided. 18. A machine as claimed in claim 15, characterised in tha the disc ( 23 ) comprises an external ring gear with whic there engages at least one gearwheel (41 ) operating under th control of the sensors ( 50 ) . 19. A machine as claimed in claim 18, characterised in tha a plurality of gearwheels (41 ) are engaged with the ring gea of the disc (23) and are connected by freewheel devices (44 to levers ( 45 ) operated with reciprocating motion under th control of the sensors (50). 20. A machine as claimed in claim 19, characterised in tha with each lever (45) there is associated a hydrauli cylinder-piston (46) fed through a solenoid valve controlle by the sensors (50). 21. A machine as claimed in claim 14, characterised in tha the sensors (50) are of contact type and are positioned i correspondence with the ideal grinding surface. 22. A machine as claimed in claim 21, characterised in tha the sensors (5 . 0) are disposed in different planes orthogona to the axis of rotation of the rotary member (20). 23. A machine as claimed in claim 20, characterised b comprising an electronic apparatus (52) which processes th signals originating from the sensors ( 50 ) and controls th members (46) for radially shifting the supports (27,33) fo the abrasive sectors (40). 24. A machine as claimed in claim 1, characterised in tha each abrasive sector (40) is mounted on the relative mobil support (33) with radial play. 25. A machine as claimed in claim 24, characterised in that the connection between each clamp ( 30 ) for locking the relative abrasive sector (40) and the support (33) for sai clamp (30) is in the form of a pair of connecting bars (36) articulatedly coupled to both to for a parallelogram. 26. A machine as claimed in claim 25 r characterised in tha the articulation between each connecting bar (36) and th clamp (30) and/or support (33) for the clamp (30) is obtaine by a mutually engaging pin (35) and slotted bore. 27. A machine as claimed in claim 1 , characterised in tha each mobile support comprises a slide (27,33) mobile radiall along the rotary member ( 0 ), and a clamp (30 ) fixed to sai slide (27) and provided with removable locking jaws for th abrasive sector (40). 28. A machine as claimed in claim 1, characterised b comprising a pro iling roller ( 53 ) constructed of diamond clad material, and having a transverse profile identical t the transverse profile of the workpiece (59) to be ground, said profiling roller (53) being located on the idea grinding surface in a position separate from the position o contact between the abrasive sectors (40) and the profil (59) to be ground.

Inventors: BALDO CLAUDIO, BALDO, CLAUDIO
Applicants: ROTRAFER SPA
Application year: 1987
Main classification: B24D5
IPC codes: B24B19, B24B27, B24D5, E01B31