Abstract:
A roller assembly for moving a billet in a furnace comprising a rotatable shaft, a roller and at least one support member. The roller has an outer rolling surface for accepting the billet thereon. The roller further includes an inner surface. The at least one support member is located between the rotatable shaft and the roller. The at least one support member includes a support surface engaging the inner surface of the roller, whereby the support surface provides support for the rolling surface of the roller, thereby preventing cracking or indenting of the rolling surface as the billet strikes the rolling surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    The present invention claims priority to Provisional Patent Application No. 60/301,208, filed on Jun. 27, 2001 entitled FURNACE ROLL ASSEMBLY. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a roller assembly, and in particular to a roller assembly for use in a high temperature furnace.  
           [0003]    Furnaces are used to heat objects to an elevated temperature. Furnaces are also used to heat treat objects placed therein to lengthen the life of the object or to provide the object with a particular desired characteristic that can be developed through heat treatment. Furnaces are further used to heat objects so the objects become malleable such that the objects can easily be formed into a certain shape or cut.  
           [0004]    Heretofore, furnaces have had inlets and outlets whereby a object can be placed into the inlet, heated in the furnace and removed from the outlet. Sometimes, the inlet can also work as the outlet. When the object placed into the furnace is a cylindrical billet, furnaces have included a plurality of rollers extending across the furnace that support the billet and move the billet from the inlet to the outlet of the furnace. The rollers typically have a cylindrical surface with a trough thereon for maintaining the billet in the trough of the roller. One problem experienced in the prior art is that when the furnace reaches temperatures of approximately 2200-2400° F., the leading edge of the billet can begin to sag downward under the force of gravity because of the malleability of the billet due to the extreme heat. When the leading edge of the billet sags, the circumferential surface of the billet directly adjacent the leading edge of the billet will not move onto the cylindrical surface of the next roller in the line between the inlet and the outlet as the billet engages the next roller. Instead, the leading edge of the billet can strike the cylindrical surface. At such extreme temperatures, the cumulative force of many billets striking the roller can cause the roller to deform and sometimes crack. Typically, the roller had to be replaced about every month or every two months. Replacing rollers usually cost large amounts of money because a roller used in a furnace reaching temperatures of approximately 2200-2400° F. is expensive to manufacture. Furthermore, as the roller is being replaced, the furnace can not be used. Therefore, the manufacturer using the furnace will lose money for the time that the furnace cannot be used to produce forged objects, as well as the time necessary for the furnace to cool prior to repairs and the time necessary to reheat the furnace after such repairs. Accordingly, a practical, economical roller that can be easily manufactured and that has a long operating life is desired.  
         SUMMARY OF THE INVENTION  
         [0005]    The aforementioned drawbacks of the prior art have been elegantly resolved through the present invention, which provides a roller assembly for moving a billet in a furnace comprising a rotatable shaft, a roller and at least one support member. The roller has an outer rolling surface for accepting the billet thereon. The roller further includes an inner surface. The at least one support member is located between the rotatable shaft and the roller. The at least one support member includes a support surface engaging the inner surface of the roller, whereby the support surface provides support for the rolling surface of the roller, thereby preventing cracking or indenting of the rolling surface as the billet strikes the rolling surface.  
           [0006]    Another aspect of the present invention is to provide a furnace having a furnace housing and a plurality of roller assemblies. The furnace housing has an inlet and an outlet. The furnace housing is configured to accept a billet through the inlet and to eject the billet through the outlet, where the billet has a direction of travel through the furnace housing. The plurality of roller assemblies are located within the furnace housing. Each roller assembly comprises a rotatable shaft, a roller and at least one support member. The roller has an outer rolling surface for accepting the billet thereon and an inner surface. The at least one support member is located between the rotatable shaft and the roller. The at least one support member includes a support surface engaging the inner surface of the roller, whereby the support surface provides support for the rolling surface of the roller, thereby preventing cracking or indenting of the rolling surface as the billet strikes the rolling surface.  
           [0007]    The principal objects of the present invention include providing a furnace roll assembly having a long operating life. The furnace roll assembly is efficient in use, economical to manufacture, capable of a long operable life, and particularly adapted for the proposed use.  
           [0008]    Other objects, advantages and features of the invention will become apparent upon consideration of the following detailed description, when taken in conjunction with the accompanying drawings. The above brief description sets forth rather broadly the more important features of the present disclosure so that the detailed description that follows may be better understood, and so that the present contributions to the art may be better appreciated. There are, of course, additional features of the disclosure that will be described hereinafter which will form the subject matter of the claims appended hereto.  
           [0009]    In this respect, before explaining the preferred embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of the construction and the arrangements set forth in the following description or illustrated in the drawings. The furnace roll assembly of the present disclosure is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for description and not limitation. Where specific dimensional and material specifications have been included or omitted from the specification or the claims, or both, it is to be understood that the same are not to be incorporated into the appended claims.  
           [0010]    As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be used as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims are regarded as including such equivalent constructions as far as they do not depart from the spirit and scope of the present invention.  
           [0011]    Further, the purpose of the Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with the patent or legal terms of phraseology, to learn quickly from a cursory inspection the nature and essence of the technical disclosure of the application. Accordingly, the Abstract is intended to define neither the invention nor the application, which is only measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.  
           [0012]    These and other objects, along with the various features and structures that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the furnace roll assembly of the present disclosure, its advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention.  
           [0013]    While embodiments of the furnace roller assembly are herein illustrated and described, it is to be appreciated that various changes, rearrangements and modifications may be made therein, without departing from the scope of the invention as defined by the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a top schematic view of a furnace of the present invention.  
         [0015]    [0015]FIG. 2 is a front view of a furnace roller assembly having a cross-section view of a locking collar and a roller of the present invention.  
         [0016]    [0016]FIG. 3 is a side view of the furnace roller assembly of the present invention taken from the right side of the furnace roller as seen in FIG. 2.  
         [0017]    [0017]FIG. 4 is a front view of a trunnion cast of the present invention.  
         [0018]    [0018]FIG. 5 is a side view of the trunnion cast of the present invention taken from the right side of the trunnion cast as seen in FIG. 4.  
         [0019]    [0019]FIG. 6 is a cross-sectional view of a drive trunnion of the present invention taken along the line VI-VI of FIG. 2.  
         [0020]    [0020]FIG. 7 is a side view of a locking collar of the present invention.  
         [0021]    [0021]FIG. 8 is a cross-sectional view of the locking collar of the present invention taken along the line VIII-VIII of FIG. 7.  
         [0022]    [0022]FIG. 9 is a partial top view of the locking collar showing a finger of the present invention.  
         [0023]    [0023]FIG. 10 is a side view of a furnace roller of the present invention.  
         [0024]    [0024]FIG. 11 is a cross-sectional view of the roller of the present invention taken along the line XI-XI of FIG. 10.  
         [0025]    [0025]FIG. 12 is a cross-sectional view of the roller of the present invention taken along the line XII-XII of FIG. 11.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as orientated in FIG. 1. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.  
         [0027]    The reference number  10  (FIG. 1) generally designates a furnace of the present invention. The furnace  10  includes a plurality of roller assemblies  12  obliquely extending across the furnace  10 . Each roller assembly  12  includes a roller  14  in the middle section of the roller assembly  12 . The rollers  14  of the roller assemblies  12  are aligned in a row. The rollers  14  are configured to accept a cylindrical object  16 , such as a billet, on a roller surface  18  of the rollers  14  as the cylindrical object  16  is forced into the furnace  10 . Preferably, the cylindrical object  16  is a steel billet used to make bearing components, although it is contemplated that other cylindrical materials used for other purposes can be forced into the furnace  10 . Accordingly, in the preferred embodiment, the furnace  10  can reach temperatures of approximately 2200-2400° F. The cylindrical object  16  is forced into the furnace  10  by a conveyor  20  at one end of the furnace  10  at the inlet thereof and forced onto consecutive rollers  14  of the roller assemblies  12  and passed through to an outlet thereof. Preferably, the furnace  10  includes thirty roller assemblies  12 . Additionally, the rollers  14  of the roller assemblies  12  are preferably positioned at approximately a 7° angle relative to a line perpendicular to the cylindrical object  16  in order to rotate the cylindrical object  16  to obtain even heating of the object  16 . Each roller assembly  12  includes a driven end  22  connected to a motor  24  for rotating the roller assembly  12  and an idler end  26  connected to an idler housing  28  for allowing the roller assembly  12  to rotate. Preferably, the roller assemblies  12  are rotated in a clockwise direction relative to the direction of travel of the cylindrical object  16  with the rollers  14  offset 7° downstream of motor  24 .  
         [0028]    The illustrated roller assembly (FIGS. 2 and 3) includes a hollow cylinder  30 , the roller  14 , a locking collar  32  locking the roller  14  to the cylinder  30 , a driven trunnion  34  on a first end of the cylinder  30  and an idling trunnion  36  on a second end of the cylinder  30 . The hollow cylinder  30  is preferably a centrifugally cast tube. The driven trunnion  34  is activated by the motor  24  to rotate the cylinder  30 , the locking collar  32  and the roller  14 . Likewise, the idling trunnion  26  is placed into the idler housing  28  to support the second end of the cylinder  30  and to allow the cylinder  30 , locking collar  32  and the roller  14  to rotate. Although the cylinder  30  is shown as being annular, it is contemplated that the cylinder could have other cross-sectional configurations, including triangular, square and hexagonal.  
         [0029]    In the illustrated example, the driven trunnion  34  and the idler trunnion  36  are made by first forming a trunnion cast  38  (FIGS. 4 and 5) and then milling, machining or otherwise removing portions of the trunnion cast  38  to form the driven trunnion  34  and the idler trunnion  36 . The trunnion cast  38  includes an annular connecting portion  40 , an annular enlarged ring portion  42  and an annular finger portion  44 . The trunnion cast  38  also includes a bore  46  having a first portion  48  within the connection portion  40 , a second larger portion  50  within the enlarged ring portion  42  and a third portion  52  partially through the finger portion  44 . The annular finger portion  44  of the trunnion cast  38  is worked to form the driven trunnion  34  and the idler trunnion  36 .  
         [0030]    The illustrated driven trunnion  34  (FIGS. 2 and 6) is connected to the cylinder  30  of the driven end  22  of the roller assembly  12 . As best seen in FIGS. 2 and 6, the finger portion  44  of the trunnion cast  38  is formed into an annular portion  54  adjacent the ring portion  42 , a hexagonal portion  56  adjacent the annular portion  54 , a first disc portion  58  adjacent the hexagonal portion  56 , a second larger disc portion  60  adjacent the first disc portion  58  and an end key portion  62  at the end of the finger portion  44 . The key portion  62  includes a keyway  64  transversely through the end of the key portion  62 . The keyway  64  is engaged with a key (not shown) in the motor  24  to rotate the roller assembly  12 . The driven trunnion  34  is connected to the cylinder  30  by inserting the connection portion  40  into an opening at the first end of the cylinder  30 . The connection portion  40  is inserted into the cylinder  30  until the enlarged ring portion  42  abuts against the cylinder  30 . The enlarged ring portion  42  and the cylinder  30  are then welded together at a weld ring  65 .  
         [0031]    In the illustrated example, the idler trunnion  36  (FIGS. 2 and 3) is connected to the cylinder  30  at the idler end  26  of the roller assembly  12 . As best seen in FIG. 2, the finger portion  44  of the trunnion cast  38  is formed into a hexagonal portion  66 . The hexagonal portion  66  is engaged with a mating idler (not shown) in the idler housing  28  to allow the roller assembly  12  to rotate. The idler trunnion  36  is connected to the cylinder  30  by inserting the connection portion  40  into an opening at the second end of the cylinder  30 . The connection portion  40  is inserted into the cylinder  30  until the enlarged ring portion  42  abuts against the cylinder  30 . The enlarged ring portion  42  and the cylinder  30  are then welded together at a weld ring  68 .  
         [0032]    The illustrated locking collar  32  (FIGS.  7 - 9 ) is placed in the middle of the cylinder  30  and locks the roller  14  to the cylinder  30  and provides support for the roller surface  18  of the roller  14 . The locking collar  32  includes a cylindrical skirt portion  70 , an open disc-shaped portion  72  at one end of the skirt portion  70  and a plurality of finger portions  74  extending from a periphery of the disc shaped portion  72 . Each of the finger portions  74  includes a tapering portion  76  extending towards the axis of the locking collar  32  and away from the periphery of the disc shaped portion  72 . The tapering portion  76  includes a pair of side edges  80  converging towards each other at a first end  82  connected to the disc shaped portion  72  and a second end  84 . Each finger portion  74  also has a flange portion  78  extending from the second end  84  of the tapering portion  76  towards the axis of the locking collar  32 . The flange portion  78  of the finger  74  is parallel to the disc shaped portion  72 . Preferably, the locking collar  32  includes eight fingers  74 . The fingers  74  assist in connecting the roller  14  to the locking collar  32 . The locking collar  32  is preferably formed of SL96D alloy, an alloy sold by Steeltech Ltd. of Grand Rapids, Mich.  
         [0033]    In the illustrated example, the roller  14  (FIGS.  10 - 12 ) is positioned in the middle of the cylinder  30  and provides a support for the cylindrical object  16  in the furnace  10 . The roller  14  includes a shell  86 , preferably having an hourglass, or V, shaped outer surface defining the roller surface  18 . Of course, arcuate outer surfaces may be used to define the roller surface  18 . The shell  86  has a hollow interior  88 . The interior  88  of the shell  86  includes a plurality of slots  90  conforming to the outside shape of the fingers  74  of the locking collars  32 . The roller  14  preferably includes a number of slots  90  equal to the number of fingers  74  on the locking collars  32 . Therefore, in the illustrated example, the roller  14  includes eight slots  90 . Consequently, each side of the shell  86  has a funnel shaped opening  92  which includes a plurality of radially extending tabs  94  defining the slots  90 . The shell  86  also includes a center inner hub  96 . The roller  14  is also preferably formed of SL96D alloy as sold by Steeltech Ltd. of Grand Rapids, Mich.  
         [0034]    The illustrated roller  14  and locking collars  32  are connected to the cylinder  30  by first inserting the cylinder  30  into the hollow interior  88  of the shell  86  of the roller  14 . Consequently, the inner hub  96  of the shell  86  has an inner diameter slightly larger than the outer diameter of the cylinder  30  such that the roller  14  will fit onto the cylinder  30 . One locking collar  32  is then slid towards the center of the cylinder  30  from each end of the cylinder  30 , with the fingers  74  of the locking collar  32  facing the center of the cylinder  30 . The locking collars  32  are then slid into the roller  14  by inserting the fingers  74  on the locking collar  32  into the slots  90  of the roller  14  until the tapering portion  76  of the fingers  74  abut the inner hub  96  of the roller  14 . The locking collars  32  are then held in position in the middle of the cylinder  30  by drilling a hole  98  through the cylindrical skirt portion  70  of the locking collar  32  and the cylinder  30 . A pin  100  is then inserted into the hole  98  and welded to the locking collar  32  to maintain the locking collar  32  from torsional and transverse motions, and therefore the roller  14 , in position (see FIG. 2). The locking collar  32  is also welded to the cylinder  30  to maintain the operational integrity of the roller  14  and the locking collar  32 . The roller  14  and the locking collar  32  solves any cracking or indentation of the roll surface  18  of the roller  14  and locks the roller  14  against linear and torsional motions caused by the force of the cylindrical object  16  against the roll surface  18  when the cylindrical object  16  is forced into the furnace  10  and onto the rollers  14 .  
         [0035]    In the illustrated example, the fingers  74  of the locking collar  32  are positioned against the inside surface of the funnel shaped opening  92  of the roller  14 . Consequently, the fingers  74  provide support for the underside of the roller surface  18  of the roller  14 . Therefore, when cold cylindrical objects  16  are forced into the furnace  10  and onto the roller surfaces  18  of the rollers  14 , the roller surface  18  will not deform if the cylindrical objects  16  are forced into, instead of on, the roller surfaces  18 . With the support formed by the fingers  74 , the roller surfaces  18  will be able to withstand the impact of the cylindrical objects  16  to force the cylindrical objects into proper position on the rollers  14 . Moreover, the clockwise rotation of the rollers  14 , coupled with the 7° offset, tends to lift the leading edge of the cylindrical object  16  as if the cylindrical object  16  is itself rotated in a counter-clockwise direction relative its direction of travel, further minimizing impacts and damage.  
         [0036]    In the forgoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.