Abstract:
A ring, preferably in the form of a lock nut, made for combi rolls, which ring includes at least one spring device in which a mechanical compression spring is included that acts between, on one hand, a front press body that is movable to and fro in order to constantly forward a spring force generated by the compression spring and, on the other hand, a support body, which may assume a fixed position, but which is adjustably movable by way of a screw in order to alter the tension in the compression spring.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a roll of the kind that comprises a drivable roll shaft and two axially spaced-apart stop rings, one of which is fixed, and the other one is a lock nut, a plurality of other rings, of which one or more are roll rings, being mounted between the stop rings.  
       BACKGROUND  
       [0002]     Rolls of the type generally mentioned above, are referred to as combi rolls by those skilled in the art. In practice, such rolls are used for hot or cold rolling of long narrow products of metal, such as wires, bars, pipes, etc. For such purposes, the roll ring or rings, i.e., the very rings which, in contrast to spacer rings and the like, carry out the forming of the metals are formed with a number of circumferential grooves, usually having a semi-circular cross section shape.  
         [0003]     An important factor for a prolonged proper function of such rolls is that the different roll and spacer rings are rotationally secured in relation to each other and in relation to the roll shaft in a reliable way, since extremely large torques are to be transferred from the shaft to the rings without the same slipping in relation to each other. To overcome this problem, tightening devices are used, which may be divided into two main categories, viz. on one hand devices, which utilize the spring force of mechanical springs, and on the other hand, hydraulically acting devices. Of these devices, the last-mentioned ones are less suitable for many reasons, e.g., the necessity to providing expensive hydraulic oil conduits to the rotating roll, the risk of oil leakage, etc. Therefore, mechanical springs are preferable, in so far that they are technically less complicated, as well as easier and more inexpensive to manufacture, install and use.  
         [0004]     In the technique in question, many proposals of mechanical springs for combi rolls have come up. One of these proposals is disclosed in U.S. Pat. No. 5,735,788, and is based on the use of a Belleville spring in the set of dismountable rings of the roll shaft. However, this solution has not been successful, among other things dependent on the placing of the spring inside the set of roll rings and spacer rings, and because of fatigue problems. It is true that the tension or the spring force of the Belleville spring in question should be possible to readjust, viz. by way of a set screw, but as a consequence of the placing thereof inside the set of dismountable rings, the spring is continuously exposed to forces, which deform, more precisely flatten the spring, something which fairly fast results in a slackening or fatigue to such an extent that the spring looses the ability to instantaneously, during operation, keep the rings pressed against each other with such a force in the friction joints there between, that the same do not slip. Furthermore, the inclined spring wears against adjacent rings in such a way that these become worn in a fairly short time due to the fact that the spring has a (circular) line contact and not a surface contact, with the rings.  
       SUMMARY  
       [0005]     The present invention aims at obviating the above-mentioned disadvantages of not only the roll presented in U.S. Pat. No. 5,735,788, but also other rolls, which make use of mechanical springs, and at providing an improved roll. Therefore, in a first aspect, a primary object of the invention is to provide a roll having a mechanically acting spring device, which can apply to the dismountable rings of the roll a high spring pressure or a high degree of prestress, with the purpose of avoiding slipping between the rings during operation, and which furthermore in a simple way can compensate the inevitable deformation, which constantly arise in the rings during operation (because of wear and deformation of the material in the same), so that the high degree of prestress is guaranteed for the instantaneous transfer of torque between the rings. An additional object is to provide a roll, the roll width (the axially available space between the fixed stop ring and the lock nut) of which is utilized in an optimal way by not being occupied by any space-demanding spring devices. Yet an object of the invention is to provide a roll in which service in respect of the spring prestress of the rings may be made in a simple and fast way.  
         [0006]     According to a first aspect, a roll comprises a drivable roll shaft and two axially spaced-apart stop rings. One of the stop rings is fixed and the other of the stop rings is a lock nut. A plurality of other rings are included. One or more of the other rings is mounted between the stop rings, wherein at least one of the stop rings comprises a spring device. The spring device is housed in a through hole extending axially and opening in opposite end surfaces of the ring. A mechanical compression spring acting between a front press body that is movable through an opening of the hole in order to constantly pass on a spring force generated by the compression spring to a ring and a support body. The support body during operation of the roll assumes a fixed position in relation to the ring. The support body being adjustable when not in operation by way of an adjusting member to alter the tension of the compression spring.  
         [0007]     In a second aspect, the invention relates to a ring as such made with built-in spring functions, and intended for the roll according to the invention. An important object of the invention in this aspect is to provide a ring, in particular in the form of a lock nut, in which one or more spring devices are included, which, on one hand, has such a great working range that considerable deformation in the different rings of the roll can be compensated for, and, on the other hand, instantaneously, during operation, provide the rings with a high, dynamic degree of prestress in order to avoid the risk of slipping. An additional object is to provide a ring made with spring functions, which ring can be mounted on and dismounted from a roll shaft in a simple way, and which furthermore is made in such a way that the active spring force of the spring devices can be adjusted in a simple and ergonomically expedient way.  
         [0008]     In a third aspect, a ring for a roll comprises a spring device housed in a through hole extending axially and opening into opposite end surfaces of the ring. A mechanical compression spring acts between a front press body that is movable through an opening of the hole in order to constantly pass on a spring force generated by the compression spring and a support body which may assume a fixed position in relation to the ring, but which is adjustably movable by way of an adjusting member in order to alter the tension of the compression spring.  
         [0009]     The invention is based on the idea of building in into a ring mountable on a roll shaft, in particular a stop ring in the form of a lock nut, a spring device in which a mechanical compression spring is included, which acts between, on one hand, a front press body, which is movable to and fro, in order to constantly pass on a spring force generated by the compression spring towards the other rings and, on the other hand, a support body which during the operation of the roll assumes a fixed position in relation to the ring, but which out of operation is adjustably movable by way of an adjusting member in order to alter the tension in the compression spring. Advantageously, a plurality of peripherically spaced-apart spring devices of this type is arranged in a circular rim formation along the ring. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     In the drawings:  
         [0011]      FIG. 1  is a partial longitudinal section through a roll according to the invention.  
         [0012]      FIG. 2  is an enlarged cross-section through a ring in the form of a lock nut included in the roll, in which a spring device according to the invention is built-in.  
         [0013]      FIG. 3  is a cross section showing only a hollow space in which the spring device is mounted,  
         [0014]      FIG. 4  is an exploded view showing the different components included in the spring device.  
         [0015]      FIG. 5  is an enlarged section of a compression spring included in the spring device. 
     
    
     DETAILED DESCRIPTION  
       [0016]     In  FIG. 1 , a combi roll is shown, which in a conventional way includes a drivable shaft or roll shaft  1  having two axially spaced-apart stop rings  2 ,  3 , one of which, viz. the stop ring  2 , is fixed, while the other one is a lock nut  3 , which is dismountable from the shaft. In the example, the fixed stop ring  2  is in the form of a ring-shaped shoulder integrated with the rest of the shaft. However, it is also feasible to make the fixed stop ring  2  in the form of a separate, dismountable ring, which in a suitable way is axially locked in relation to the shaft.  
         [0017]     Between the fixed stop ring  2  and the detachable lock nut  3 , a number of dismountable rings is arranged, of which certain are roll rings  4 , and certain are spacer rings  5 . Between the lock nut  3  and the roll ring  4  positioned closest to the same, there is an additional ring  6 , the design of which may deviate from the design of the spacer rings  5 , and which below is referred to as tightening ring. Generally, the roll shaft  1  as well as the different rings have a rotationally symmetrical, more precisely cylindrical, basic shape, the rings being delimited by planar end contact surfaces. Of the end surfaces, only the opposite end surfaces of the lock nut  3  are provided with reference designations  7 ,  8 , as is seen in  FIGS. 2 and 3 . On the cylinder-shaped inside thereof, the lock nut (see  FIG. 1 ) is formed with a female thread  9  that is in engagement with a male thread  10  of the roll shaft. The roll rings  4 , which have the purpose of providing the direct roll forming work, and which for this purpose have circumferential, peripheral grooves  11 , may advantageously be manufactured from cemented carbide or other wear-resistant materials, while the intermediate rings  5 ,  6  may be composed of a softer metal, e.g., steel or cast iron. However, the material in the different rings is incidental for the realization of the invention. The essential thing is that the friction joints in the interfaces between the end surfaces of the rings efficiently prevent slipping between the rings. For this purpose, the rings have to be held sustainedly compressed by a great spring force or prestress.  
         [0018]      FIGS. 2-5  illustrate in detail the nature of a spring device  12  which is built-in into the lock nut  3 . In  FIG. 2 , the spring device is shown mounted in the lock nut, while  FIG. 3  shows only a through hole in which the spring device is accommodated, and  FIG. 4  is an exploded view showing the individual components of the spring device spaced-apart from each other.  
         [0019]     The above-mentioned hole, which extends axially through the lock nut  3 , and which generally is designated  13 , includes, on one hand, a front or inner section  14  that opens in the end surface  7  turned inward of the lock nut and, on the other hand, a rear section  15 , which via a widened countersink  16  opens in the rear or outward end surface  8  of the lock nut. In the example, the front hole section  14  has a diameter that is greater than the diameter of the hole section  15 , the countersink  16  in turn having a greater diameter than the section  15 . The inner surface of the front hole section  14  is smooth and cylindrical, while the rear hole section  15  along the entire length thereof is formed with a female thread  17 .  
         [0020]     The active component of the spring device  12  (see  FIG. 4 ) is a compression spring  18  that acts between a front press body  19  and a rear stop or support body  20 . In the exemplified embodiment, the press body  19  is composed of a suitably cylindrical pin having a flange  21 , against which the front end of the compression spring  18  may be urged. The support body  20  is in the form of a piston which, in addition to a cylindrical envelope surface  22 , has a suitably planar back side  23 , as well as a front side  24 , in which a central seat  25  opens, a rear end of the press body  19  engaging the seat. A screw  26  may be tightened in the hole section  15  with the male thread  27  thereof in engagement with the female thread  17 . A head  28  of the screw is housed in the countersink  16 . A Seeger ring  29  has the purpose of holding the different spring components in place in the hole  13 .  
         [0021]     In the shown, preferred embodiment of the invention, the compression spring  18  is a cup spring that includes a plurality of cups  30 ,  31 , arranged in a united set. A number of first cups  30  in the set are turned with their small ends pointing in an opposite direction to the small ends of the other cups  31 . More precisely, the cups  30  are placed in such a way that the small ends point to the left in  FIG. 5 , while the small ends of the cups  31  point to the right. In such a way, the two intermediate cups will have contact with each other along the outer, peripherical edges thereof, while the two outermost cups are pressed with the internal edges thereof against, on one hand, the flange  21  of the press body  19  and, on the other hand, the front surface  24  of the piston  20 .  
         [0022]     The support body  20 , the spring  18 , the press body  19 , and the Seeger ring  29  are, upon mounting, inserted in proper order in the hole section  14 , while the screw  26  is inserted from behind in the threaded hole section  15 . The Seeger ring  19  has only the purpose of holding the spring components  20 ,  18 ,  19  in place in the hole section  14 .  
         [0023]     In the drawings, only one individual spring device  12  is shown. However, in practice, the lock nut  3  is made with a plurality of peripherical spring devices which are spaced-apart and arranged in a circular rim formation. For instance, the lock nut may include eight equidistantly spaced-apart spring devices along the circumference thereof.  
         [0024]     When the roll rings  4  and other rings  5 ,  6  have been applied to the roll shaft  1 , as is shown in  FIG. 1 , the lock nut  3  is tightened on the male thread  10 . More precisely, the lock nut is tightened by a considerable pressure against the tightening ring  6 . When the lock nut has reached a maximally tightened end position, the spring devices  12  are activated, more precisely by the fact that the individual screw  26  is screwed-in a distance in the hole. As a consequence of the free front end of the press body  19  being urged against the tightening ring  6 , the compression spring  18  will then be compressed, more precisely by the fact that the piston moves in the forward direction in the hole section. When the piston by way of the screw reaches a position in which the desired spring prestress has been achieved, the tightening of the screw is terminated. Thereafter, the roll is ready to be taken into operation.  
         [0025]     During operation, the different rings of the roll shaft are exposed to dynamic stresses that in an effective way are carried by the compression springs in the different spring devices. More precisely, the individual spring forces are transferred to the common tightening ring  6  in which they are distributed so that the same will act with an even, high pressure against the adjacent roll ring  4 . Because the compression springs in the described way are made in the form of powerful cup springs, a dynamic spring action is attained and maintained during long working operations. However, if the spring force eventually is reduced, readjustment may be effected, viz. by additional tightening of the screws  26  so as to press in the pistons additionally into the holes. In such a way, the springs are compressed afresh to the desired degree of prestress.  
         [0026]     An important advantage of the roll according to the invention, and the spring arrangement included therein, is that the spring prestress between the rings in a simple way may be held reliably high. This in turn guarantees that the rings do not slip in relation to each other.  
         [0027]     Another significant advantage is that the means being necessary for the spring prestress, do not occupy any part of the roll width, i.e., the available space between the stop rings  2 ,  3 . The invention is not limited only to the embodiment described above and shown in the drawings. Thus, it is feasible to arrange the described spring devices in the fixed stop ring  2  instead of in the lock nut  3 . It is even possible to arrange spring devices in the fixed stop ring as well as the movable lock nut.  
         [0028]     The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced.