US3860387A

US3860387A - Roller for supporting a workpiece in a furnace or the like

Info

Publication number: US3860387A
Application number: US414443A
Authority: US
Inventors: Francis H Bricmont
Original assignee: Bricmont and Associates Inc
Current assignee: Andritz Metals Inc
Priority date: 1973-11-09
Filing date: 1973-11-09
Publication date: 1975-01-14
Anticipated expiration: 1992-01-14

Abstract

Rollers support a metallic workpiece during heating within a furnace. The rollers are constructed to avoid localized cooling by the supporting contact between the rollers and the workpiece. These rollers include a workpiece engaging sleeve designed to withstand heating within the furnace. A water-cooled arbor supports the sleeve by a series of interconnections to minimize heat transfer from the sleeve to the arbor. These interconnections include rings attached at spaced locations along the arbor for supporting arcuate segments in a spaced and radially-extending manner. The segments have at their ends arcuate shoe plates for supporting engagement with the internal surface of the sleeve. A conical-shaped sleeve forms an enclosure at each end of the sleeve by interconnecting the arbor and the sleeve. A key is used to drivingly interconnect the arbor with one of the conical sleeves and hence the roller support sleeve itself.

Description

United States Patent [1 1 Bricmont Jan. 14, 1975 ROLLER FOR SUPPORTING A WORKPIECE IN A FURNACE OR THE LIKE [75] Inventor: Francis H. Bricmont, Pittsburgh, Pa.

[73] Assignee: Bricmont 8L Associates, Inc.,

Pittsburgh, Pa.

[ 1 Filed: Nov. 9, 1973 1 App]. No: 414,443

Primary Examiner-John J. Camby Attorney, Agent, or Firm-Brown, Murray, Flick & Peckham [57] ABSTRACT Rollers support a metallic workpiece during heating within a furnace. The rollers are constructed to avoid localized cooling by the supporting contact between the rollers and the workpiece. These rollers include a workpiece engaging sleeve designed to withstand heating within the furnace. A water-cooled arbor supports the sleeve by a series of interconnections to minimize heat transfer from the sleeve to the arbor. These interconnections include rings attached at spaced locations along the arbor for supporting arcuate segments in a spaced and radially-extending manner. The segments have at their ends arcuate shoe plates for supporting engagement with the internal surface of the sleeve. A conical-shaped sleeve forms an enclosure at each end of the sleeve by interconnecting the arbor and the sleeve. A key is used to drivingly interconnect the arbor with one of the conical sleeves and hence the roller support sleeve itself.

10 Claims, 4 Drawing Figures PATENTED JAN 1 4 I975 ll'IllllllIlllIll-ll'lll ROLLER FOR SUPPORTING A WORKPIECE IN A FURNACE OR THE LIKE BACKGROUND OF THE INVENTION This invention relates to a roller hearth for a workpiece heating furnace and, more particularly, to a roller construction for the support of workpieces while they are heated in a furnace so that during heating, the temperature of the workpiece is uniform throughout, notwithstanding supporting contact with the rollers.

In the past, roller-type hearths have been provided in furnaces to support numerous different forms of workpieces as, for example, a plurality of bars during heating within the furnace. Heavy metallic plate has been heated by conveying it through successively arranged furnaces or tandem heating zones within one or more furnaces. Such workpieces are heated for a number of different reasons, all of which usually are characterized by the need to supply heated workpieces from the furnaces at a uniform temperature. The actual temperature to which these workpieces are heated depends upon the particular metalworking or treating operations but, generally, the workpieces are raised to a temperature above the critical temperature of the metal and frequently it is desired to raise the temperature of the workpiece to 2,000 F or higher.

In some heating furnace designs, water-cooled skids are used to support the workpiece during heating. The results, however, are undesirable because pronounced cold spots are formed at each area where the workpiece was supported on the skids. This is particularly undesirable where the workpieces are heated prior to quenching, rolling, leveling and other processing operations involving metal deformations. There are other forms of furnace hearths known in the art which involve the use of rollers to support the workpiece. These rollers are typically constructed through the use of a trunnion mounted to the ends of an alloyed tube forming the roller body. The temperature of the roller is increased in essentially the same manner as the workpiece supported thereby during heating. Such a roller construction is subject to certain critical disadvantages which the present invention is designed to overcome. While the alloyed tube forming the body portion of the roller is allowed to attain the operating temperature within the oven, thus avoiding cold spots on the workpieces being heated, the rollers bend and distort as a result of creep and the relatively high loading by the workpieces they support. This distortion and bending become particularly acute when the rollers must operate at temperatures ranging from ambient to 2,000F.

Another severe disadvantage of the known roller construction is brought about by the need to rotatably support the rollers at their ends. These rollers are usually driven, thus requiring some form of bearings to reduce friction. These bearings must be specially designed to operate not only at high temperatures but also over a wide range of temperatures and, therefore, usually require water cooling. As heat is withdrawn from the bearings at each end of the roller, there is effectively produced a heat sink, thus reducing the surface temperature of the roller body causing thermal stress in the roller and adversely affecting the uniform heating of the workpieces.

SUMMARY OF THE INVENTION It is an object of the present invention to provide in a workpiece heating furnace or the like, a roller hearth to support the load incurred due to the weight of a workpiece during heating without bending or distortion of the roller due to the operating temperature within the furnace.

It is a further object of the present invention to provide a roller construction for supporting a workpiece within a furnace or the like wherein the roller includes a sleeve that attains the same temperature as the workpiece during heating while load bearing support for the sleeve is provided by a water-cooled arbor having at spaced locations radially-extending load transfer members which minimize heat transfer from the sleeve to the arbor.

More specifically, according to the present invention, there is provided in combination with a heating furnace or the like for metallic workpieces, a roller apparatus for supporting such workpieces in a manner to avoid localized cooling during heating of the workpiece, the apparatus comprising an elongated arbor having an internal opening for coolant extending in an axial direction of the arbor, bearing means for rotatably supporting the ends of the arbor, a sleeve member supported on the enlarged arbor for carrying the workpiece dur ing heating to an elevated temperature, and load transfer means at spaced locations along the arbor and extending radially into engagement with the internal surface of the sleeve for transfer of the load imposed by the workpiece to the arbor with a minimum of heat transfer between the sleeve and the arbor.

In the preferred form, the present invention further includes conical sleeves at the ends of the arbor, one of the sleeves is interconnected to the arbor by a key in a torque-transmitting relation for a driving force. The present invention may additionally include providing insulation in void areas between the arbor and the sleeve.

These features and advantages of the present invention as well as others will be more readily understood when the following description is read in light of the accompanying drawings, in which:

FIG. 1 is an elevational view, in section, of a heating furnace incorporating workpiece support rollers according to the present invention;

FIG. 2 is an enlarged view, in section, of the roller construction according to the present invention;

FIG. 3 is a sectional view taken along line III--lII of FIG. 2; and

FIG. 4 is an enlarged view similar to FIG. 2 and taken along line lV-IV of FIG. 3.

With reference now to FIG. 1, there is illustrated a furnace 10 typically employed for heating workpieces to elevated temperatures such as up to 2,000 "F or greater. For the purpose of a description of the present invention, reference will be made to a normalizing furnace wherein a plate 1 l is heated preparatory to undergoing heat treating operations, leveling or similar processing. The furnace includes

side walls

12 and 13 which support a roof l4. Openings are provided in the side walls at spaced locations along tHe length of the furnace for receiving a roller assembly 15 to support the plate 11. The design of the furnace may include the use of heating units 16 located in a chamber below the rollers and other heating units 17 suspended from the roof above the plate 11.

Each roller 15 is rotatably supported at its ends by bearing assemblies 21. The rollers 15 include an extension at one end which is connected to a sprocket 22 connected by a chain on gear drive system 23 which is, in turn, driven by a motor 24 for propelling the plate 11 relative to the furnace walls. Each roller, at its end opposite the sprocket 22, is connected to a coolant supply system which includes a rotary union 25 and a coolant supply pipe 26 extending downwardly toward the floor at the outside of the furnace.

FIGS. 2, 3 and 4 illustrate in greater detail the construction of each roller 15. As indicated previously, the rollers are supported at their ends by bearing assemblies 21. As clearly shown in FIG. 2, the bearing assemblies engage and are received on the end of an arbor 31 which has an internal passageway 32 extending in an axial direction along its length. The passageway 32 is connected to the rotary union 25. At spaced locations along the length of the arbor 31, a disc-like ring 33 is welded to the arbor and extends radially. Four arcuate segments 34 are secured to each ring 33 at spacedapart locations forming air gaps between the arcuate segments.

FIGS. 3 and 4 illustrate in greater detail, the arrangement of the arcuate segments in relation to each of the rings 33. It will thus be observed that diametricallyopposed arcuate segments 34 form pairs that are secured to opposite sides of the ring 33. To the extended end of each arcuate segment, there is secured a shoe plate 35 that, in turn, engages the internal surface 36 of a sleeve 37 which defines the body of the roller. The assembling of the roller may be readily carried out by arranging the various support elements which include the rings 33, the segments 34 and shoe plates 35 on the arbor and then sliding the sleeve 37 over these parts for support thereby. It will thus be observed and it is a feature of the present invention that the use of the spacedapart support elements for the sleeve not only provides increase strength for sustaining the weight of the workpieces carried by the roller, but also contributes materially to reducing the transfer of heat from the sleeve 37 which is heated to the same temperature as the workpieces. At the same time, in order to provide adequate support for the workpiece, the arbor is cooled by the passage of coolant to the internal passageway 32. In this arrangement, the water-cooled arbor acts as a beam to support the load but not as a heat sink. The rising temperature of the workpiece is practically unaffected by the water cooling of the arbor since there is only a relatively small metal-to-metal contact between the arbor and the sleeve for the conduction of heat. The use of the water-cooled arbor has the added advantage of maintaining the arbor at a temperature around 150F, for example, so that the bearing assemblies 21 are protected from overheating, thus greatly reducing the cost of providing rollers for the furnace.

Since the temperature of the sleeve 37 is heated throughout a substantial temperature range, the sleeve expands a far greater amount than the arbor 31, of the order of 3 or more inches. To accommodate this relative displacement between the sleeve and the arbor, according to the present invention, there is provided conical-shaped

end sleeves

41 and 42 that are welded or otherwise connected to the sleeve 37 at its ends. The conical-shaped sleeve 41 is slidably connected to the arbor by a key 43 to establish a positive driving relation between the arbor and the sleeve. In addition, since the sleeve 41 is held on the arbor in a driving relation, it can expand in an axial direction relative thereto and,

therefore, it is possible to weld the sleeve 42 to the arbor and thereby accommodate all axial growth of the sleeve due to temperature changes. In order to further reduce the transfer of heat from the sleeve 37 to the arbor, insulation material 45 on reflective coatings may be used in the spaces between the plurality of support structures for the sleeve.

Although the invention has been shown in connection with a certain specific embodiment, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to suit requirements without departing from the spirit and scope of the invention.

1 claim as my invention:

1. In combination with a heating furnace for metallic workpieces, a hearth including rollers for supporting at spaced-apart location such workpieces in a manner to avoid localized cooling of the workpieces during heating thereof, said rollers comprising an elongated arbor having an internal opening extending in an axial direction of the arbor for the passage of coolant, bearing means for rotatably supporting the ends of the arbor, an elongated sleeve member having an essentially continuous outer cylindrical face surface for uniform support and engagement along the length thereof with a workpiece during heating to an elevated temperature, said sleeve member having an internal diameter essentially larger than the outer diameter of said elongated arbor for providing an annular space therebetween to form a thermal barrier, and support means carried at spaced locations along said arbor for extending into a load transferring relation with said internal surface of the sleeve member, said support means at each location along the arbor including a plurality of support segments spaced one from the other along said arbor and extending radially in an essentially discontinuous and non-overlapping relation for reduced heat transfer in such a manner so as to improve creep resistant properties of the sleeve member arising out of the segmented support thereof at each location along the length of the arbor while transferring the load imposed by a workpiece during heating within said furnace.

2. An apparatus according to claim 1 wherein said support means at each location along the arbor are discontinuous within two transverse planes passing through said sleeve member.

3. The apparatus according to claim 1 further comprising means for drivingly interconnecting said arbor and said sleeve, and means coupled to said arbor for rotating said sleeve to displace a workpiece supported thereby within said furnace.

4. An apparatus according to claim 3 wherein said means for drivingly interconnecting includes a conicalshaped end sleeve secured to one end of said sleeve member, a key member extending between the end sleeve and said arbor.

5. The apparatus according to claim 4 further comprising a conical-shaped end sleeve secured to the other end of said sleeve member.

6. An apparatus according to claim 1 wherein said support means at each spaced location along the arbor includes a ring secured to said arbor, a plurality of arcuate segments secured to said ring in a spaced-apart relation for extending radially from said ring toward said sleeve.

7. An apparatus according to claim 6 further comprising an arcuate shoe plate secured to each extended said support means.

10. An apparatus according to claim 6 wherein said plurality of arcuate segments includes diametricallyopposed segments secured to one side of said ring, other diametrically-opposed segments secured to the other side of said ring and forming an air gap between adjacent segments extending from said ring.

Claims

1. In combination with a heating furnace for metallic workpieces, a hearth including rollers for supporting at spacedapart location such workpieces in a manner to avoid localized cooling of the workpieces during heating thereof, said rollers comprising an elongated arbor having an internal opening extending in an axial direction of the arbor for the passage of coolant, bearing means for rotatably supporting the ends of the arbor, an elongated sleeve member having an essentially continuous outer cylindrical face surface for uniform support and engagement along the length thereof with a workpiece during heating to an elevated temperature, said sleeve member having an internal diameter essentially larger than the outer diameter of said elongated arbor for providing an annular space therebetween to form a thermal barrier, and support means carried at spaced locations along said arbor for extending into a load transferring relation with said internal surface of the sleeve member, said support means at each location along the arbor including a plurality of support segments spaced one from the other along said arbor and extending radially in an essentially discontinuous and non-overlapping relation for reduced heat transfer in such a manner so as to improve creep resistant properties of the sleeve member arising out of the segmented support thereof at each location along the length of the arbor while transferring the load imposed by a workpiece during heating within said furnace.

4. An apparatus according to claim 3 wherein said means for drivingly interconnecting includes a conical-shaped end sleeve secured to one end of said sleeve member, a key member extending between the end sleeve and said arbor.

7. An apparatus according to claim 6 further comprising an arcuate shoe plate secured to each extended end of said segment for engaging the internal surface of said sleeve.

8. An apparatus according to claim 1 further comprising coolant supply means communicating with said internal opening extending in an axial direction along said arbor.

9. An apparatus according to claim 1 further comprising insulating means disposed in the spaces between said support means.

10. An apparatus according to claim 6 wherein said plurality of arcuate segments includes diametrically-opposed segments secured to one side of said ring, other diametrically-opposed segments secured to the other side of said ring and forming an air gap between adjacent segments extending from said ring.