Abstract:
A lifting device for temporarily supporting a trunnion of a paper roll to relieve a bearing and its bearing block of load to facilitate replacement of the bearing. The lifting device includes an arch yoke and a cradle yoke having torque arms which are rigidly interconnected by releasable fasteners and which extend axially alongside laterally opposite sides of the bearing block, thus permitting support members, such as extensible jacks, to be placed beneath the torque arms at laterally opposite sides of the bearing block.

Description:
BACKGROUND OF THE INVENTION 
   In the process of making paper from wood pulp, a continuous sheet of damp paper is removed from a supporting web and wound up on a large support roll having relatively large diameter hollow trunnions through which a heating medium is passed to complete the drying of the paper being wound on the roll. The paper roll trunnions are mounted in bearings which are housed in a pair of bearing blocks releasably secured near the edges of horizontal floors of a pair of spaced stationary support structures. Although the bearings are designed to provide a relatively long service life, they eventually will wear with use to such an extent that they need to be replaced. When replacing the bearing, the bearing and the bearing block in which it is installed must be removed from the associated trunnion. The paper roll is very large and hence is quite heavy. The axial end of the paper roll from which the bearing and its bearing block are being removed must be lifted to relieve the bearing of load to permit removal of the bearing block and replacement of the bearing. The bearing block is mounted so close to the edge of the support that it is not possible to place a supporting jack directly under the trunnion when replacing the bearing. 
   SUMMARY OF THE INVENTION 
   A device is provided to lift and support a trunnion on one axial end of a paper roll to permit removal of a bearing block and its accompanying bearing. The device includes two releasably interconnected thrust transmitting components, which engage axially spaced top and bottom portions, respectively, of the trunnion. Each of the yokes has a pair of axially extending and horizontally spaced parallel torque arms. The arms are disposed at corresponding lateral sides of the bearing block, are releasably secured to one another and a lifting force is applied to the arms at one or both sides of the bearing block, thereby relieving the bearing block and its associated bearing of the paper roll load. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One embodiment of the invention is illustrated in the accompanying drawings, in which: 
       FIG. 1  is a side view of a paper roll and its supporting structure; 
       FIG. 2  is a section taken on line  2 — 2  in  FIG. 1 ; 
       FIG. 3  is an end view with the lifting device installed on one of the paper roll trunnions; 
       FIG. 4  is a top view taken on line  4 — 4  in  FIG. 3 ; 
       FIG. 5  is a side view taken on line  5 — 5  in  FIG. 4 ; 
       FIG. 6  is an end view showing lifting jacks in supporting relation to the lifting device; 
       FIG. 7  is an end view showing the lifting jacks and lifting device supporting a paper roll trunnion from which the bearing block and its bearing have been removed; 
       FIG. 8  is a section taken on line  8 — 8  in  FIG. 7 ; 
       FIG. 9  is an end view of the upper thrust transmitting component; 
       FIG. 10  is a top view of the upper thrust transmitting component; 
       FIG. 11  is a side view of the upper thrust transmitting component; 
       FIG. 12  is a side view of the lower thrust transmitting component; 
       FIG. 13  is a top view of the lower thrust transmitting component; and 
       FIG. 14  is an end view of the lower thrust transmitting component. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a paper roll  11  which has trunnions  12 ,  13  supported on a foundation, in the form of horizontal floors  14 ,  14 ′ of a pair of rigid supports  15 ,  15 ′, by bearing blocks  17 ,  18  which have a tongue and groove connections with bases  19 ,  21 , respectively, secured to the supports  15 ,  15 ′ by fasteners  22 . The bearing blocks  17 ,  18  are maintained in supported position on the bases  19 ,  21  by retainers  23  releasably secured to opposite sides of the bases  19 ,  21 . The bases  19 ,  21  and the bearing blocks  17 ,  18  are supported by the floors  14 ,  14 ′ very close or adjacent to the edges  16 ,  16 ′ of the supports  15 ,  15 ′, thereby making it impractical, if not impossible to place a support member directly beneath one of the trunnions  12 ,  13  of the paper roll  11 . 
   As shown in  FIGS. 2 ,  3 ,  6 ,  7  and  8 , the trunnion  13  has a central concentric passage  26  through which a heating fluid is transmitted by fluid transmission apparatus  27  to the interior of a spool  11 ′ of the paper roll  11  via interior piping  31  to aid in drying the damp paper being rolled onto the roll  11 . A cylindrical end portion  32  of the trunnion  13  is supported in a cylindrical opening  30  of the bearing block  18  by an anti-friction roller bearing  33  for rotation about a drum axis  20 . The trunnion  12  is supported in the bearing block  17  in a similar manner. The trunnions  12 ,  13  have annular flanges  34 ,  35  with radially outward facing annular or cylindrical shoulders  36 ,  37 , respectively. The flanges  34 ,  35  are bolted to axially opposite ends of the spool  11 ′ of the paper roll  11 . 
   As illustrated in  FIGS. 9 through 14 , a lifting device  40  for supporting one axial end of the paper roll  11  has two main thrust transmitting components, namely, an arch yoke  41  and a cradle yoke  71 . The arch yoke  41  includes an arch  42  having a downward facing cylindrically shaped surface  43  of the same or slightly larger radius as the cylindrical shoulders  36 ,  37  of the trunnions  12 ,  13 . A pair of parallel torque arms  44 ,  46  are rigidly secured to and extend horizontally from opposite ends  48 ,  49  of the arch  42  and parallel to the axis  47  of the arch surface  43 . Arm  44  includes a pair of parallel plates  51 ,  52  with first corresponding ends welded to one side of the end  48  of the arch  42  and a spacer block  53  between and welded to the plates  51 ,  52 . Three vertical holes  54  are formed in the block  53 . The axes of the holes  54  lie in a vertical plane parallel to the axis  47  of the surface  43 . The arm  46  is constructed in a similar manner with plates  61 ,  62  welded to the end  49  of the arch  42 , a block  63  welded to the plates  61 ,  62  and vertical holes  64  in the block  63 . The axes of the holes  64  lie in a vertical plane which is parallel to the axis  47 . 
   Referring to  FIGS. 12 ,  13  and  14 , the cradle yoke  71  includes bowed cradle  72  presenting an upward facing cylindrical surface  73  of the same or slightly larger radius as the cylindrical end portion  32  of the trunnion  13 . A pair of parallel torque arms  74 ,  76  are rigidly secured to opposite ends  77 ,  78  of the cradle  72  and extend horizontally at right angles thereto and parallel to the axis  79  of the cylindrical surface  73 . Arm  74  includes spacer blocks  81 ,  82  welded to parallel spaced plates  83 ,  84  and arm  76  includes spacer blocks  86 ,  87  welded to parallel spaced plates  91 ,  92 . The spacer blocks  81 ,  82  of the arm  74  have three threaded vertical openings  101  lying in a vertical plane parallel to the axis  79  of the cylindrical surface  73 . In a similar manner the spacer blocks  86 ,  87  of the arm  76  have three threaded vertical openings  101  lying in a vertical parallel to the axis  79 . The threaded openings  101  are spaced axially from one another in the direction of axis  79  and are adapted to receive releasable fasteners in the form of cap screws or threaded studs  102 . When the cradle yoke  71  is installed on the trunnion  13 , as shown in  FIGS. 4 ,  7  and  8 , a semi-circular retainer loop  106  is releasably connected to the cradle  72  by cap screws or fasteners  107  threaded into drilled and tapped vertical openings  108 ,  109  in the cradle  72 . The retainer loop  106  holds the cradle yoke  71  in an appropriate position on the cylindrical end portion  32  of the trunnion  13  thereby facilitating rigid connection of the arch yoke  41  and the cradle yoke  71  to one another, as shown in  FIGS. 4 through 8 ; wherein releasable fasteners in the form of cap screws or threaded studs  102  have been passed through vertical openings  54 ,  64  in the arms  44 ,  46  of the arch yoke  41  and threaded into the threaded openings  101  in the arms  74 ,  76  of the cradle yoke  71 . 
   When it has been determined that a trunnion bearing needs to be replaced, the heating fluid delivery apparatus  27  is removed from the bearing block  18 , the cradle yoke  71  is installed with the upward facing cylindrical surface  73  in upward thrust transmitting relation to the underside of the cylindrical portion  32  of trunnion  13  between the bearing block  18  and the flange  35  as shown in  FIGS. 4 and 5 . The retainer loop  106  is then secured to the cradle yoke  71  by releasable fasteners  107 . Next the arch yoke  41  is positioned on the trunnion  13  by placing its cylindrical bearing surface  43  in downward thrust transmitting engagement with the cylindrical shoulder  37 . The cap screws  102  are then installed through openings  54 ,  64  and threaded into the tapped openings  101  rigidly interconnecting the yokes  41 ,  71  to one another. The lifting device  40  is thus coupled to the trunnion  13  as shown in  FIGS. 3 through 8 . In preparing to remove the bearing block  18  and its bearing  33 , the bearing block retainers  23  are removed. 
   Next, two support members or jacks  131 ,  132  are placed beneath the torque arms  74 ,  76 , respectively, and at least one of the support members  131 ,  132  is adjustable to elevate the trunnion  13  a slight amount. When the bearing  33  is thus relieved of the paper roll load the bearing  33  and bearing block  18  can be removed from the trunnion  13  with conventional bearing removal tools.  FIG. 7  shows the lifting device  40  and the jacks  131 ,  132  supporting the trunnion  13 . After replacing the bearing  33  with a suitable replacement bearing, the bearing block  18  and the newly installed bearing are installed on the cylindrical end portion  32  of the trunnion  13 , the previously extended jack or jacks are lowered and removed, the retainers  23  are installed, the lifting device  40  is removed and the fluid transmission apparatus  27  is reconnected to the bearing block  18 . 
   It will be noted that in supporting the trunnion  13 , the torque arms  44 ,  46  are secured to torque arms  74 ,  76 , respectively, to form a pair of lever arms exerting upward thrust by the cradle yoke  71  and downward thrust by the arch yoke  41 . This lever action places an upward thrust on the trunnion  13 , relieving the load on the bearing  33  when either or both of the jacks  131 ,  132  are extended to raise the trunnion  13  a slight amount. The bearing, not shown, in the bearing block  17  can be replaced by following a procedure like that herein described for replacing the bearing  33 . The lifting device  40  is advantageously used to replace trunnion bearings in those instances where the bearing block is mounted near the edge of a support and there is insufficient space to place a jack or other lifting device directly beneath the trunnion.