Abstract:
A method of clamping and locking a roll for a steel mill on a driving pinion comprising applying a side thrust force against a roller to clamp it against a shoulder on the pinion whilst applying the reaction force produced by the side thrust force to cause a plug located in a cavity in the pinion beneath the roll to move sideways. The plug is provided with threads which when the plug is moved sideways produces a wedging action which expands the mounting surface on which the roll is mounted to lock the roll on the driving pinion.

Description:
[0001]     This invention is an improvement on U.S. Pat. No. 5,700,233, U.S. Pat. 6,526,795 and U.S. Provisional Application No. 60/338,670 filed Dec. 11, 2001.  
       BACKGROUND OF THE INVENTION  
       [0002]     The reduction of steel in a mill requires the presence of very robust equipment. The reduction of a steel bar to wire is usually accomplished by means of a series of reducing stands in which a pair of mating rolls are mounted on stout pinions so as to be able to exert sufficient force on a steel work product passing between the mating rolls to enable the rolls to distort the work product to a work product with a reduced cross sectional area.  
         [0003]     It will be seen that not only do the mating rolls have to produce great force on the work product, but the rolls must produce a torque to pull the work through between the reducing rolls.  
         [0004]     The reducing rolls are usually mounted at the end of a driving shaft (usually referred to as a pinion) in such a manner as to be able to exert substantial force in order to reduce the cross section of the work as it passes between the rolls and the pinion must transmit considerable torque from the pinion to each roll in order to pull the work between the rolls.  
         [0005]     In order to produce an acceptable work product in which the cross section of the end work product is within an acceptable range, the rolls must be very precisely and accurately mounted on the pinion to reduce eccentricity to an acceptable value. Above all the roll must never be allowed to slip on the driving pinion (because of the possible introduction of eccentricity to the roll rotation) because of the possibility of the rejection of the resulting work product due to variations in gauge.  
       SUMMARY OF THE INVENTION  
       [0006]     This invention relates to a method of mounting a reducing roll on a pinion in such a manner that the roll is tightly clamped on the pinion by the production of a compressive force on the roll (which presses the roll firmly against a shoulder on the driving pinion) whilst a simultaneous is force expands the diameter of pinion on which the roll is mounted. In this invention, the production of these two forces is interdependent, thus as the force causing the increase in diameter of the roll mounting surface of the pinion is being produced, a simultaneous reaction force is being produced which clamps the roll tightly against a shoulder on the driving pinion. An increase in one of the above forces automatically causes an increase in the other force.  
       PERTINENT PRIOR ART  
       [0007]     U.S. Pat. No. 6,526,795  
         [0008]     U.S. Pat. No. 5,700,233 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a plan view of the roll and pinion of this invention;  
         [0010]      FIG. 2  is a perspective view of the invention of  FIG. 1 ;  
         [0011]      FIG. 3  is a cross sectional view of the roll and pinion of  FIG. 1 ;  
         [0012]      FIG. 4  is an enlargement of a section of  FIG. 3 ;  
         [0013]      FIG. 5  is an exploded view of the roll and pinion of  FIG. 1 ;  
         [0014]      FIG. 6  is a plan view of an alternative embodiment of this invention;  
         [0015]      FIG. 7  is a sectional view of the invention illustrated in  FIG. 6 ;  
         [0016]      FIG. 8  is an end view of the invention of  FIG. 6 ;  
         [0017]      FIG. 9  is a cross sectional view of the invention shown in  FIG. 8 ;  
         [0018]      FIG. 10  is an enlarged detail illustration of the circled portion of  FIG. 9 ;  
         [0019]      FIG. 11  is a sectional perspective of the invention of  FIG. 1 ;  
         [0020]      FIG. 12  is an exploded view of the device of  FIG. 1 .  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]      FIG. 1  shows the general shape of the finished roll mounting assembly  10 . The assembly  10  comprises a pinion  12  having a shoulder  14 . A composite spacer assembly comprising a pair of rings  16  is mounted on pinion  12  against shoulder  14 . A roll  18  is next mounted on pinion  12 . A seal ring  20  is mounted on pinion  12  next to roll  18 . A cap  22  is next mounted on the assembly  10 .  
         [0022]     Referring to  FIG. 3  it will be necessary to describe the interior of pinion  12 . Pinion  12  is provided with a hollow chamber  24  which is threaded with a buttress type thread of a very shallow slope (see U.S. Pat. No. 5,700,233). A plug  26  having a similar mating shallow buttress thread is threaded into chamber  24  as shown in  FIG. 3 . When plug  26  has been advanced a satisfactory distance into cavity  24 , three headless bolts  28  are threaded through clearance holes  30  in plug  26  and into threaded holes  32  in pinion  12 . Bolts  28  prevent plug  26  from twisting in pinion  12  once the plug  26  has reached its “home” position.  
         [0023]     Cap  22  is now threaded on to plug  26  at threaded portion  32  (See  FIG. 4 ). Pinion  12  is provided with an annular flange  34  which surrounds lip  36  of cap  22  with a clearance fit.  
         [0024]     Cap  22  is provided with seal ring  38  to prevent the ingress of foreign particles such as mill scale into the assembly  10 . A series of pressure bolts  40  are threaded into cap  22  at threaded holes  42 . Bolts  40  are provided with seal rings  44  to prevent the ingress of foreign particles into the assembly  10 .  
         [0025]     Plug  26  is provided with shallow buttress type threads as shown in inset drawing  45 .  
         [0026]     Cap  22  is provided with a series of holes  46  which permits an operator to insert a tool therein to tighten or loosen cap  22  on the threaded end  32  of plug  26 .  
         [0027]     In operation, plug  26  is first threaded into the chamber which is provided with a surface threaded with threads  25 . Plug  26  is threaded into the threaded chamber until the end of plug  26  nearly contacts the bottom of the chamber. Next bolts  28  are inserted into the clearance holes  30  provided in plug  26  and bolts  28  are subsequently tightened into threaded holes  32  provided in pinion  12 . Bolts  28  prevent plug  26  from undergoing any rotational motion during operation of the assembly  10 .  
         [0028]     Next, a spacer ring assembly  16  is placed on pinion  12  against shoulder  14 . Roll  18  is next mounted on pinion  12  against spacer ring assembly  16 . Cap  22  carrying seal ring  38  is threaded on to plug  26  at threads  32 .  
         [0029]     When the cap  22  has been tightened on plug  26  to a predetermined torque, the tightening of pressure bolts  40  may begin. Bolts  40  are tightened in succession to: (1) clamp roll  18  against shoulder  14  of pinion  12 ; and (2) to cause expansion of the surface of the pinion beneath roll  18 . Torquing bolts  40  will force roll  18  to move slightly to the left as shown in  FIG. 3  causing plug  26  to move to the right by the reaction force produced by torquing pressure bolts  40 . The reaction force produced by bolts  40  on cap  22  urges plug  26  to the right ramping the buttress threads  25  and thus expanding cavity  24 . As bolts  40  are torqued to the predetermined limit, in sequence, the pinion surface beneath roll  18  is evenly expanded by the plug  26  which maintains the concentricity of roll  18  on pinion  12 . At the same time, bolts  40  assure that roll  18  is held firmly in place against spacer assembly  16  which in turn abuts shoulder  14  of pinion  12 .  
         [0030]      FIGS. 6-12  show an alternative form of the invention in which the roll is clamped in the pinion assembly  110  by hydraulic pressure.  
         [0031]     Referring to  FIGS. 6-9  and  FIG. 6  in particular, it will be seen that pinion assembly  110  comprises a pinion  112  on which is provided a shoulder  114  against which spacer rings  116  are located. A roll  118  is shown mounted on pinion  112 . A thrust ring  120  is next shown mounted adjacent to and abutting roll  118  of assembly  110 . Cap  122  is mounted adjacent thrust ring  120  of the assembly  110 .  
         [0032]     Referring now to  FIGS. 7-10 , it will be seen that a plug  126  (identical to previously shown plug  26 ) is threaded into cavity  124  of pinion  112  and bolts  128  which are threaded into holes  132  in pinion  112  to prevent plug  126  from rotating during operation of this device.  
         [0033]     A piston plate  150  is threaded onto plug  126  at threads  133 . Piston plate  150  is somewhat disc shaped and is provided with threads  133  to engage plug  126 . Piston plate  150  is probably best illustrated in  FIG. 12  and is provided with flange  152  ( FIG. 10 ) to fit within flange  134  of pinion  112  ( FIG. 10 ). Piston plate  150  is provided with a cylindraceous surface  154  which mates with the surface of the thrust ring  120  and an annular recess  156  which is provided for seal ring  158 . At a larger diameter, piston plate  150  is provided with a cylindraceous surface  160  in which a sealing ring groove  162  is provided for seal ring  164 .  
         [0034]     A hydraulic fluid pressure adapter  170  is threaded into piston plate  150  at threads  172 . Pressure adapter  170  is provided to the assembly  110  to provide ready connection to an external source of hydraulic pressure. An internal pressure duct  174  in adaptor  170  is shown in communication with radially extending distribution ducts  176 . A pair of seal rings  178  are installed on adapter  170  at the surface which mates with piston plate  150 .  
         [0035]     Duct  174  is provided with a pair of ball checks  184  and  186  to maintain the internal pressure in the system when the external source of hydraulic pressure is removed.  
         [0036]     Referring to  FIG. 9  it will be seen that pressure release channels  180  are provided in piston plate  150  to bleed hydraulic fluid from the assembly  110 . Pressure release channels  180  are normally closed by bleeder plugs  182 .  
         [0037]     It will be seen in  FIGS. 7 and 9  that piston plate  150  and thrust ring  120  form an annular pressure chamber  190  which is in communication with ducts  176  and  180  bormed in piston plate  150 .  
         [0038]     Assembly and operation of this pinion assembly is as follows:  
         [0039]     Roll  118  and spacer rings  116  are first placed on pinion  112 . Plug  124  is next threaded into cavity  124  until a predetermined “home” position is reached. Headless bolts  128  are next threaded into pinion  112  to secure plug  126  against any further rotation of plug  126 .  
         [0040]     Next thrust ring  120  is fitted onto piston plate  150  and the assembly comprising piston plate  150 , thrust ring  120  are threaded onto plug  126  at threads  133 . Final torquing of piston plate  150  on plug  126  may be accomplished by means of hexagonal head  192  ( FIG. 12 ) provided thereon.  
         [0041]     When the assembly ( 150 ,  120 ) is in place, adapter  170  may be threaded into piston plate  150 . Bleeder plugs  182  will have to be removed to permit bleeding of the assembly  110 . When the unit is ready for pressurization bleeder plugs  182  are replaced.  
         [0042]     A source of external hydraulic pressure is applied to adaptor  170 . This pressure is applied to chamber  190  by means of ducts  174  and  176 . As soon as chamber  190  becomes pressurized, thrust ring  120  is forced to the left whilst the reaction force which is applied to piston plate  150  tends to pull the plug  126  to the right. As with the previous version of this assembly, these two forces are equal and opposite. When a predetermined pressure is reached in chamber  190 , the pressure source is removed from adaptor  170  (ball checks  184  and  186  maintain the pressure) and cap  122  is installed on pressure plate  150  at threads  192 .  
         [0043]     When it is desired to remove roll  118  from the pinion assembly  110 , cap  122  is unscrewed from piston plate  150  and one or all bleeder plugs  182  are removed from piston plate  150  to release the hydraulic pressure in chamber  190 .  
         [0044]     The piston plate  150 , thrust collar  120  assembly is next removed by unscrewing piston plate  150  from plug  126  and it will be seen that the roll mounting surface of pinion  112  will have contracted sufficiently that the roll may be easily removed from pinion  112 .