Wire Drawing Apparatus

Abstract: The lubricant container (9) is mounted on the top of the body (1) of the drawplate holder, so that it can be traversed parallel to its own axis (100) and so that, when it is withdrawn from the drawplate housing, the container (9) is kept closed below by means (201-6) coplanar with the upper face of the said body. The said container (9) is provided laterally with an aperture (12) extending over its whole height, closed by a flap (14) which is normally closed and can open inwards only. When the wire has been inserted into the drawplate (23), the lubricant container (9) is brought into the operating position above the drawplate (23) and in this phase the side flap of the container (9) interacts with the portion of wire preceding the drawplate (23), which opens the flap and slides into the lubricant container (9). To prevent the formation of cakes of lubricant before the drawplate (23), the drawplate holder is subjected to the action of suitable means which cause the fragmentation and/or progressive erosion of the said cakes and/or directly prevent their formation.

Description: The present invention relates to a wire drawing apparatus and more particularly to a drawplate holder, which is the device used in drawing apparatuses and disposed between each wire drawing drum, to support the drawplate which reduces the section of the wire. The drawplate holders are normally cooled by forced circulation of cooling liquid and are commonly associated with containers of stearate-based dry powdered lubricant, through which the wire passes before entering the drawplate, so that the wire is conveniently lubricated. Such type of wire drawing apparatuses are disclosed, for example, in documents EP-A-0 504 846, US-A-2 257 644 and DE-A-2 234 109. In the wire drawing apparatuses of the known type, the following problems are encountered. The threading of the wire through the lubricant container and through the drawplate, or what is known as the operation of threading the drawplate in the initial phase in which the drawing apparatus is prepared for operation, currently requires a preliminary reduction of section of a long portion of wire, which is rather labour-intensive and takes a relatively long time to carry out. A first object of the invention is to simplify and accelerate the operation of threading the drawplate and the attached lubricant container, as claimed in claims 1 to 3. Another problem encountered in wire drawing apparatuses of the known type with a container of dry powdered lubricant associated to the drawplate, is that of the formation, immediately before the drawplate, of a cake formed by the lubricant softened by the heat produced by the wire passing through the drawplate, which prevents the free flow of the lubricant powder towards the drawplate and the good adhesion between wire and lubricating powder. Documents GB-A-795 462 and JP-A-59-215210 illustrate this type of problem and solutions proposed thereto. A further object of the invention is to subject therefore the said lubricant cake formed inside the container to a mechanical action which causes its break-up or progressive erosion and/or which directly prevents its formation, as claimed in claims 4 and 5. These and other objects are achieved with a drawplate whose characteristics will be evident from the following description of certain preferred embodiments, illustrated purely by way of example and without restriction in the figures on the two attached sheets of drawings, in which: Fig. 1 is a plan view of the drawplate holder, with the powder lubricant container marked more clearly; Fig. 2 is a side elevation of the drawplate holder, viewed in the direction indicated by the arrow K in Figure 1; Fig. 3 shows the drawplate holder in partial section along the line III-III in Figure 1; Fig. 4 shows a variant embodiment of the drawplate holder again viewed along the section line III-III in Figure 1. In Figures 1-2-3, the number 1 indicates the body of the drawplate holder, which in the example in question is provided laterally and in an intermediate position with a transverse rib 101 lying between a pair of parallel lugs 2 welded on the visible face of the vertical wall 103 of the draw-bench, with which the said rib is associated with the possibility of oscillating about an axis 4 orthogonal to the axis 100 of the drawplate holder and the corresponding drawplate (see below). On the same wall 103, in a position equidistant from the lugs 2, there is mounted perpendicularly an adjusting screw 5 which interacts with an intermediate and lower part of the body 1, to permit the precise orientation of the axis of the drawplate with respect to the means of guiding and drawing the wire disposed before and after the said drawplate. Since the connection of the drawplate holder to the corresponding supporting structure is extraneous to the innovations described here, it should be understood that other suitable means may be provided to produce this connection. The body 1 has at its top a projecting bracket 201, integral or attached, orientated with its largest dimension parallel to the previously mentioned axis of oscillation 4, the upper face of the said bracket and the top of the body 1 being shaped to form a single plane 6, perpendicular to the axis of the drawplate and substantially horizontal. On a median area of this plane, close to the side facing the wall 103, there is fixed perpendicularly a pivot 7, which rotatably supports the lugs 8 provided laterally on the lubricant powder container 9, and on whose top there are fitted Belleville springs 10 retained axially by an elastic ring 11 and acting on the upper lug 8 to push the said container downwards and force its lower edge to adhere closely to the plane 6. The container 9 is completely open in its lower part and the lubricating powder is retained in it by the plane 6. The container 9 is also open in its upper part, but here it is provided with an inturned rim 109 which has the primary function of imparting a satisfactory rigidity to the container. In Figures 1-2-3, the container 9 is illustrated with a continuous line in the operating position in which it is above the body 1 of the drawplate holder to supply the lubricating powder by gravity to the drawplate. In Figure 1 it will be seen that the container 9 is provided, in a lateral area facing the wall 103 when the container is in the operating position, with an aperture 12, extending over its whole height, and also through the upper rim 109, having an exact width and being disposed on a theoretical circumference 13 having its centre in the axis of the pivot 7 and passing through the axis 100 of the drawplate holder. The aperture 12 is closed by a leaf spring 14 disposed inside the container 9, having the same height as the container and being fixed to it by one of its vertical sides, for example by bolts 15 or other suitable means. The leaf 14 consequently prevents any outflow of lubricant powder from the aperture 12. When the drawing machine has to be prepared for operation, the container 9 is rotated about the pivot 7 and brought into the position indicated by broken lines in Figure 1, away from the body 1 of the drawplate holder which is thus uncovered above. The plane 6 continues to close the container 9 below. With a suitable device, the operator reduces the section of the wire to be drawn, in an end portion and over a length sufficient to permit the introduction of the wire, from above, through the axial cavity of the body 1 and of the attached drawplate (see below) and to ensure that the wire can be gripped at its end and drawn longitudinally until the portion of wire before the drawplate holder is under sufficient tension. At this point, the operator rotates the container 9 about the pivot 7 and brings it into the operating position. The portion of wire before the body 1 comes into contact with the outer face of the leaf spring 14 and swings this into the container as necessary to allow the wire to slide into the said container, after which the spring returns to the position in which it closes the aperture 12, thus preventing any outflow of lubricant powder. To facilitate this operation, the upper rim 109 of the container 9 nearer the movable end of the spring 14 is suitably distant from the spring, as indicated by 209 in Figure 1. To resolve the other problem mentioned in the introduction to the present description, the following provision is made. In Figures 1 and 3, the number 16 indicates the plug with a conical axial hole which axially secures in its housing the drawplate which, in known solutions, is mounted in the body 1 so that it can rotate about its own axis. The housing carrying the drawplate is provided for this purpose in its lower part with a ring gear 17 which engages with a small pinion 18 keyed to the shaft of a small electric motor 19 of the step-by-step type, fixed by its casing to a lateral appendage 301 of the body 1 and operated so that it transmits to the drawplate a continuous unidirectional rotation at a speed matched to the linear speed of advance of the wire through the drawplate. The number 20 indicates a small protective casing for the gearing 17-18, fixed to the appendage 301 and provided with a hole 21 for the passage of the wire which passes through the drawplate. The axial hole 22 of the plug 16, conical and converging in the direction of the drawplate, is engaged by an appendage 124 of any suitable shape, which does not interfere with the wire passing through the drawplate, and which is integral with the end of a flat lever 24 disposed in a recess formed on the top of the body 1 and pivoted transversely at its end, at 25, in the end part 26 of the said recess which is such that the lever 24 is fully coplanar with the plane 6. It will be obvious that, with the rotation which the motor 19 transmits to the drawplate and to the assembly 22-16, the appendage 124 executes a mechanical breaking-up action which prevents the formation of any harmful cake of lubricant before the drawplate. To enable work to be carried out on the drawplate, after the container 9 has been withdrawn by rotation on the pivot 7 as stated above, the lever 24 is raised into the position indicated by broken lines in Figure 3. The drawplate holder shown in Figure 3 is cooled by a known method by forced circulation of liquid. Figure 4 shows a simplified embodiment of the drawplate holder in which the drawplate 23 is housed in a housing 29 formed directly in the body 1, where it is axially secured by the plug 16 and with the interposition of sealing rings 27-28. The holes 31-32 for the entry and exit of the cooling liquid, and a thermostatic sensor 33, terminate in the lateral space 129 between the housing 29 and the drawplate 23, which is partially delimited by a ring of projections 30 of the said housing. The formation of harmful cakes of lubricant before the drawplate 23 is prevented in this case by the vibrations imparted to the body 1 by any appropriate device 34 suitable for the purpose, fixed for example to the lateral appendage 301 of the said body. It is to be understood that the description refers to certain preferred embodiments of the invention, to which numerous variations and modifications, especially in respect of construction, may be made without departure from the invention as claimed below. In the following claims, the references given in brackets have the sole purpose of facilitating the reading of the claims, and therefore should not be interpreted in any restrictive way in respect of the scope of protection of the claims.

Claims: A wire drawing apparatus comprising a holder (1) for a drawplate (16, 23) through which the wire passes in a substantially vertical direction, and a lubricant feeding device for lubricating the wire, said lubricant feeding device including a vertical container (9) open at the top and at the bottom and which contains dry powdered lubricant through which the wire passes, characterized by the fact that the said vertical container (9) presents its bottom end resting on the top surface of the body of the drawplate holder (1) and is associated with the said holder for relative movement therewith parallel to its vertical axis (7) from an operative position above the drawplate (16, 23) to an inoperative position laterally to the said drawplate, means (201-6) coplanar with and lateral to the top of the body of the drawplate holder being provided acting as a closure of the bottom of the container (9) in said inoperative position, the said container (9) for the lubricant being provided laterally over its whole height with an aperture (12) maintained normally closed by an internal flap (14) which can be opened only if pushed inwards by a portion of the vertical wire inserted into the drawplate, upon movement of the container from its inoperative to its operative position. An apparatus according to Claim 1, characterized in the te body (1) of the said drawplate holder has on its top a projecting bracket (201) which forms, with the said top, a single plane (6) on which the open lower end of the lubricant container (9) rests and is sealed, the container being pivoted by at least one pair of lateral lugs (8) to a pivot (7) parallel to the axis of the said container and fixed to the plane (6) which closes the bottom of the said container, which is kept pushed against the said plane by suitable elastic means (10) disposed on the said pivot and acting on one of the said lugs, the lateral aperture (12) of the said container being disposed on a theoretical circumference (13) which has its centre in the axis of the said pivot (7) and which substantially passes through the centre of the said container. An apparatus according to Claim 1, in which the lateral aperture (12) of the lubricant container (9) is closed by a leaf spring (14) disposed inside the said container and fixed to one of the edges of the said aperture by means of bolts, rivets or other suitable means (15). An apparatus holder according to Claim 1, characterized in that the drawplate is mounted coaxially in an axially hollow hub, which in turn is mounted rotatably on bearings in a vertical housing in the drawplate holder body (1) from which the said hub projects below for keying to a ring gear (17) which engages with a small pinion (18) keyed to the shaft of a small electric motor (19), which is fixed to a lateral appendage (301) of the said body (1) and which transmits to the drawplate assembly a undirectional continuous rotation, a small appendage (124), which does not interfere with the wire and which is integral with the end of a lever (24) disposed in a recess, being disposed in the axial cavity (22) of the screw plug (16) which axially secures the drawplate in the housing of the said hub and which is open inside the lubricant container (9) located above it. An apparatus according to Claim 1, in which the drawplate (23) is mounted with the appropriate plug (16) for axial securing directly in a housing (29) formed in the body (1) of the said drawplate holder, and in which passages (31, 32, 129) for a cooling liquid are obtained, a device (34), of any type capable of generating vibrations which are transmitted to the interior of the drawplate holder and which prevent the formation of harmful cakes of lubricant immediately before the drawplate, being fixed to a lateral appendage (301) on the lower part of the said body.

Inventors: MACCAFERRI ANGELO, MACCAFERRI, ANGELO
Applicants: MECCANICA DI PRECISIONE SPA, S.A.M.P. S.P.A. MECCANICA DI PRECISIONE
Application year: 1995
Main classification: B21C3
IPC codes: B21C3, B21C9