Die-holder box with rotating die particularly for drawing metal wires

Abstract: Die-holder box with rotating die, particularly for drawing metal wires, which comprises a chamber (2) for the lubrication of the metal wire to be drawn which is fixable on a base (1), a drawing and cooling chamber (3) and a gearmotor (4). The die-holder box furthermore comprises rotating supporting means (17) for supporting a double die (34,36) which is immersed within a cooling liquid (15) inside the drawing and cooling chamber (3). The rotating supporting means comprise means (22) for connection to the gearmotor (4) and are sealingly inserted within parallel walls (5,7,9 and 11) of the drawing and cooling chamber (3).

Description: The present invention relates to a die-holder box with rotating die particularly for drawing metal wires. Various solutions are currently used in machines for drawing metal wires from wire rods and the like. In order to allow correct drawing however, known methods have several technical problems. In the various types of drawing machines currently in use, there are considerable problems related to the cooling of the die, to the penetration of the lubricant within moving parts, and to the inspection of the drawing region during the processing of metal wires. The practicality in the extraction of the dies themselves is also an important issue. Numerous die-holder boxes are currently known, both of the fixed-die type and of the rotating-die type, which have so-called indirect cooling, i.e., the cooling of the die, which is usually made of special steel with the addition of metallic carbides and which is inserted in a torroidal steel support, is performed by cooling said torroidal support with a cooling fluid, such as for example water and the like. Known from BE-A-524,858 is a machine for drawing metal wire having a die-holder which is mounted rotatably, and means for positively driving the die-holder. The wire to be drawn is fed, preferably substantially tangentially, to the die holder. The machine has conduits for feeding cooling water to a circular opening provided on the die holder, and a vessel containing powdered soap lubricant for lubrication of the wire being drawn. Also known from GB-A-563,828 is a wire drawing machine wherein wire to be drawn is lubricated by being passed through a box containing powdered soap. The box is rotatably mounted and rotation of the box is used to impart rotary motion to a rotatably mounted die casing. In order to cool the die, a supporting bearing for the die casting is provided with a first annular chamber surrounding the casing and a series of ports which connect the first annular chamber to a second annular chamber in a stationary ring surrounding the bearing and provided with a wager inlet and an outlet. Also known from the document FR-A-1 081 760 is a die-holder box as defined in the preamble of Claim 1. The greatest disadvantages of said cooling are related to the durability of said die and to the maintenance of its internal diameter, i.e. of the constancy of the diameter of the wire being drawn. The lubricant, which is usually a viscous compound based on soapwort with the addition of various additives, furthermore causes various problems to the moving parts of rotating-die drawing machines. As the temperature rises, the lubricant in fact tends to solidify, and its penetration for example in the gears for transmitting motion from the reduction units to the die causes their seizure, with evident problems of production halting and of increase in the costs of said production. Inspection of the drawing region, which is generally performed by an operator which directly inspects the condition of the process, is practically impossible. Furthermore, in order to improve drawing, i.e. to improve the durability of the die and to standardize the diameter of the drawn wire, so far the most effective type is the double-die pressure type. However, due to the problems related to lubrication and cooling, only fixed non-rotating double dies or rotating double dies with indirect cooling are used. The aim of the present invention is to eliminate the disadvantages described above in known types of die-holder box by providing a box with a rotating die particularly for drawing metal wires which eliminates the problems related to the cooling of the die, facilitates the operations for inserting and removing the die and allows continuous inspection. Within the scope of the above aim, an object of the present invention is to provide a die-holder box which eliminates the problems related to the penetration of lubricant in the moving mechanical parts. Another object of the present invention is to provide a die-holder box which provides an easy and simple access for the inspection of the drawing region. Not least object of the present invention is to provide a drawing machine which is relatively easy to manufacture and at competitive costs. This aim, the objects mentioned and others which will become apparent hereinafter are achieved by a die-holder box with rotating die, particularly for drawing metal wires, as defined in claim 1. Further characteristics and advantages of the invention will become apparent from the description of a preferred but not exclusive embodiment of a die-holder box with rotating die particularly for drawing metal wires, according to the invention, illustrated by way of example in the accompanying drawings, wherein: figure 1 is a front elevation view of a preferred embodiment of a die-holder box according to the invention; figure 2 is a sectional side view of the die-holder box, taken along the plane II-II of figure 1; figure 3 is a sectional bottom view of the die-holder box, taken along the plane III-III of figure 2; and figure 4 is a sectional elevation view of the die-holder box, taken along the plane IV-IV of figure 3. With reference to the above described figures, a die-holder box with rotating die, particularly for drawing metal wires, according to the invention, comprises a metal wire lubrication chamber 2 which is fixed on a base 1, a drawing and cooling chamber 3 and a gearmotor 4. A lubricating substance 16 is stored in the lubrication chamber 2 and is composed for example of additive soapwort. The drawing and cooling chamber 3 is separated from the lubrication chamber 2 by means of a first wall which is divided into three layers: a first layer 5 which faces the chamber 2 and has a hole 6 in a median position; a second layer 7 which has a step-shaped cavity 8; and a third layer 9 which also has, in a median position, a step-shaped cavity 10. The layers 5, 7 and 9 are assembled in a per se known manner, for example by means of bolts, and can thus be easily disassembled in order to perform any repair or maintenance intervention. A second wall 11 of the chamber 3 also has a hole 12 in a median position. The first wall, made of the wall layers 5,7 and 9, and the second wall 11 are interconnected by a third wall 13 and fourth wall 14, to thereby delimit the cooling chamber 3. The first wall and the second wall 11 are substantially parallel, whereas the third wall 13 and the fourth wall 14 are not mutually parallel. Indeed, as more clearly illustrated in figures 1 and 4, the third wall 13 is inclined toward the outside of the chamber 3 so as to conveniently allow better access to said chamber 3. Rotating supporting means for a double pressure die or for a single die immersed within a cooling liquid 15 are furthermore comprised within the cooling chamber 3. Said rotating supporting means comprise means for connection to the gearmotor 4 and are sealingly inserted within the first wall and the second wall 11 of the drawing and cooling chamber 3. The rotating supporting means comprise a first cup-shaped element 17 which has a cavity 18 which is connected, by means of the hole 6, to the lubrication chamber 2; the metal wire, indicated by a double dashed line in figure 2, penetrates in said cup-shaped element 17, which is provided with a wire exit hole 19. The first cup-like element 17 is inserted, so as to define a seal ensured by gaskets 20 and 21 interposed between the outer surface of the first cup-like element 17 and the inner surface of the cavities 8 and 10, within the first wall, as previously described, of the drawing and cooling chamber 3. Said first cup-shaped element 17 supports, on its own outer surface, the means for connection to the gearmotor 4, which are constituted by a gear 22, and bearings 23 for its own rotation with respect to the first wall. The gear 22 and the bearings 23 are kept in position on the first cup-shaped element 17 by means of a fixing element 41, such as a snap ring or a split ring, which is inserted within the outer surface of said cup 17. The gearmotor 4 comprises a motor 24 and a reducer 25 which has, as illustrated in figures 3 and 4, motion transmission gears 26 and 27; the gear 27 meshes with the gear 22 so as to rotate the first cup-shaped element 17. Cross-members 28 protrude, preferably monolithically, from the first cup-like element 17 and connect said element 17 to a support 29 which is inserted, so as to define a seal ensured by gaskets 30, within the hole 12 of the second wall 11 and supports, on its own outer surface, bearings 31 for the rotation of the support 29. The cross-members 28 define an accommodation seat for a single or double interchangeable die, which is formed by a first die 34, which can be inserted within a recess 35 of the first cup-shaped element 17, and by a second die 36, which sealingly rests on a plug 39 associated with the support 29; a wire guiding block 37 is inserted between the first die 34 and the second die 36. The single or double pressure die can be inserted on the cup 17 in a radial direction with respect to the axis of said cup, simply by acting on the plug 39, which is then locked, creating the packing force for the fixing and sealing of the die. The cooling fluid 15 makes direct contact with the die or dies 34 and 36 so as to remove therefrom the heat caused by the traction of a winding drum, not illustrated, on the metal wire being processed. The support 29 bears, in an axial portion, the plug 39 which protrudes from the second wall 11; said plug 39 has a plurality of holes 40 for engagement with a screwing tool. The drawing and cooling chamber 3 has, on a bottom 42, means for feeding a cooling liquid or fluid 15 into said chamber 3; said means, as illustrated in figure 4, can be either a simple liquid feed or a spray nozzle 43. The drawing and cooling chamber 3 has an upper cover 44 which is provided with a removable handle 45 which constitutes an access for inspecting said chamber. Said cover can be advantageously partially transparent so as to be able to inspect the chamber. Inspection of the chamber 3 is particularly important, since it is thus possible to intervene in the drawing operations as soon as lubricant 16 leaks into the cooling liquid 15 occurs. If a lubricant leak occurs, maintenance actions are immediately taken in order to correct it. The interchangeable single or double pressure die can advantageously be replaced by means of the removable upper cover 44 without having to perform interventions for the axial insertion and removal of the die as occurred up to now. A liquid drain 46 is inserted within the drawing and cooling chamber 3 and protrudes from the bottom 42, passing through the base 1 in order to discharge excess fluid 15 from said chamber. As is well-known in the art, in order to orientate the die-holder box there are centering screws 50 and 51 which are fixed in the lower portions of the lateral walls which rest on the base 1 and affect lateral walls of a reference protrusion 52 which is fixed to the base 1 and the lateral faces whereof are inclined so as to approach the axis of said protrusion from the top downward. It has been observed that the die-holder box according to the invention achieves the intended aim and objects, constituting an extremely advantageous alternative to known machines, since it in fact provides a rotating drawing machine with direct cooling and with a single or double pressure die, which so far has never been provided. The die-holder box therefore combines, in itself, the advantages related to an optimum drawing, which are due to the rotation of the dies, with the advantages of durability and maintenance at optimum temperature related to the use of direct die cooling. In practice, the materials employed, as well as the dimensions, may be any according to the requirements. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of the claims.

Claims: Die-holder box, particularly for drawing metal wires, comprising a wire lubrication chamber (2) fixed on a base (1), a drawing and cooling chamber (3) communicating with said lubrication chamber (2), rotating means (17) for supporting an interchangeable direct-cooling die (34,36) inside said drawing and cooling chamber (3), said rotating support means (17) being sealingly inserted within walls (5,7,9,11) of said drawing and cooling chamber (3), and means (22,24) for rotating said rotating support means (17), characterized in that it comprises a removable cover (44) provided on said drawing and cooling chamber (3) for radial insertion of said direct-cooling die (34,36), into said drawing and cooling chamber (3). Die holder box according to claim 1, characterized in that said removable cover (44) is provided on said drawing and cooling chamber (3) radially above said interchangeable direct-cooling die (34,36). Die-holder box according to claim 2, characterized in that said rotating supporting means (17) comprise a first cup-shaped element (17) sealingly inserted within a first wall (5,7,9) of said drawing and cooling chamber (3) and having an outer surface supporting a gear (22) and bearings (23) for allowing rotation of said first cup-shaped element (17) with respect to said first wall (5, 7, 9), cross-members (28) monolithically connecting said first cup-like element (17) to a support (29), sealingly inserted within a second wall (11) of said drawing and cooling chamber (3) and having an outer surface supporting bearings (31) for allowing the rotation of said support (29) with respect to said second wall (11), said support (29) delimiting an accommodation seat for a die locking plug (39), said removable cover (44) being located between said first wall (5, 7, 9) and said second wall (11). Die-holder box according to claim 3, characterized in that said cross-members (28) define an accommodation seat for said interchangeable direct-cooling die (34,36) below said removable cover (44). Die-holder box according to claim 3, characterized in that it comprises a third wall (13) and a fourth wall (14) extending between said first and second walls (5, 7, 9, 11) of said drawing and cooling chamber (3), said third wall (13) being inclined with respect to said fourth wall (14) for facilitating access to said rotating means (17) and said interchangeable direct-cooling die (34,36) via said removable cover (44). Die holder box according to claim 6, characterized in that said removable cover (44) is at least partially transparent. Die-holder box according to claims 3 and 6, characterized in that said interchangeable direct-cooling die (34,36) is replaceable in said rotating supporting means (17) through said removable cover (44), without removal of said die locking plug (39) from said accommodation seat delimited by said support (29). Die-holder box according to claim 1, characterized in that it comprises means (43) for delivering cooling liquid (15) to said drawing and cooling chamber (3), and a drain (46) inserted within said drawing and cooling chamber (3) for discharging excess cooling liquid (15), said drain (46) passing through said base (1) and extending upwardly within said drawing and cooling chamber (3) from the bottom (42) thereof to a level above said interchangeable direct-cooling die (34,36), whereby to maintain said interchangeable direct-cooling die (34,36) immersed in cooling liquid (15). Die holder box according to claim 3, characterized in that said first wall (5,7,9) of said drawing and cooling chamber (3) comprises a first layer (5) facing said lubrication chamber (2), a second layer (7) having formed therein a step-shaped cavity (8), a third layer (9) having formed therein a step-shaped cavity (10), at least one gasket (20) interposed between the outer surface of said rotating support means (17) and said step-shaped cavity (8) formed in said second layer (7), and at least one gasket (21) interposed between the outer surface of said rotating support means (17) and said step-shaped cavity (10) formed in said third layer (9).

Inventors: ARNOLDI LUIGI, FRIGERIO MARCO, ARNOLDI, LUIGI, FRIGERIO, MARCO
Applicants: FRIGERIO MARIO SPA, MARIO FRIGERIO S.P.A.
Application year: 1992
Main classification: B21C3
IPC codes: B21C3