Furnace roll assembly

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

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] FIG. 1 is a top schematic view of a furnace of the present invention.

[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] 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] FIG. 4 is a front view of a trunnion cast of the present invention.

[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] 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] FIG. 7 is a side view of a locking collar of the present invention.

[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] FIG. 9 is a partial top view of the locking collar showing a finger of the present invention.

[0023] FIG. 10 is a side view of a furnace roller of the present invention.

[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] 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.

Claims

1. A roller assembly for moving a billet in a furnace comprising: a rotatable shaft; a roller having an outer rolling surface for accepting the billet thereon, the roller further including an inner surface; and at least one support member located between the rotatable shaft and the roller, the at least one support member including 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.

2. The roller assembly of claim 1, wherein: the at least one support member comprises a pair of locking collars locking the roller to the rotatable shaft.

3. The roller assembly of claim 2, wherein: the locking collars include a plurality of fingers defining the support surface; the roller includes a plurality of slots conforming to the shape of the fingers and defining the inner surface; and the fingers engage the slots to lock the roller onto the rotating shaft and to rotate the roller with the rotating shaft.

4. The roller assembly of claim 3, wherein: the rolling surface of the roller is non-linear and is thereby adapted to force the billet thereon into a center area of the rolling surface.

5. The roller assembly of claim 3, wherein: the inner surface of the roller is generally parallel to adjacent portions of the rolling surface of the roller.

6. The roller assembly of claim 5, wherein: the support surface of the locking collar is generally parallel to the inner surface of the roller.

7. The roller assembly of claim 3, wherein: the roller includes a central inner hub contacting the rotatable shaft, the central inner hub dividing the inner surface of the roller into a first inner surface and a second inner surface.

8. The roller assembly of claim 7, wherein: ends of the fingers of the locking collars abut a side of the central inner hub of the roller.

9. The roller assembly of claim 7, wherein: the first inner surface includes a plurality of first depending tabs depending therefrom, the first depending tabs defining a first set of the slots; and the second inner surface includes a plurality of second depending tabs depending therefrom, the second depending tabs defining a second set of the slots.

10. The roller assembly of claim 9, wherein: the first and second depending tabs are integral with the central inner hub; and the first and second depending tabs are tapered in a direction moving away from the central inner hub.

11. The roller assembly of claim 10, wherein: each locking collar includes a skirt surrounding the rotatable shaft, a flange extending away from the skirt, and the fingers; and the fingers extend away from the flange in a direction opposite to the hub.

12. The roller assembly of claim 11, wherein: the fingers taper in a direction moving away from the flange.

13. The roller assembly of claim 12, wherein: each of the fingers include a tab extending therefrom, and each of the tabs abuts a side of the central inner hub of the roller.

14. The roller assembly of claim 13, wherein: the tab extends in a direction parallel to the direction of the flange.

15. The roller assembly of claim 1, wherein: the rotatable shaft is hollow.

16. A furnace comprising: a furnace housing having an inlet and an outlet, the furnace housing configured to accept a billet through the inlet, the furnace housing further configured to eject the billet through the outlet, the billet having a direction of travel through the furnace housing; and a plurality of roller assemblies located within the furnace housing, each roller assembly comprising a rotatable shaft, a roller and at least one support member; wherein the roller has an outer rolling surface for accepting the billet thereon, the roller further including an inner surface; and wherein the at least one support member is located between the rotatable shaft and the roller, the at least one support member including 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.

17. The furnace of claim 16, wherein: the at least one support member comprises a pair of locking collars locking the roller to the rotatable shaft.

18. The furnace of claim 17, wherein: the locking collars include a plurality of fingers defining the support surface; the roller includes a plurality of slots conforming to the shape of the fingers and defining the inner surface; and the fingers engage the slots to lock the roller onto the rotating shaft and to rotate the roller with the rotating shaft.

19. The furnace of claim 18, wherein: the rolling surface of the roller is non-linear and is thereby adapted to force the billet thereon into a center area of the rolling surface.

20. The furnace of claim 18, wherein: the inner surface of the roller is generally parallel to adjacent portions of the rolling surface of the roller.

21. The furnace of claim 20, wherein: the support surface of the locking collar is generally parallel to the inner surface of the roller.

22. The furnace of claim 18, wherein: the roller includes a central inner hub contacting the rotatable shaft, the central inner hub dividing the inner surface of the roller into a first inner surface and a second inner surface.

23. The furnace of claim 22, wherein: ends of the fingers of the locking collars abut a side of the central inner hub of the roller.

24. The furnace of claim 22, wherein: the first inner surface includes a plurality of first depending tabs depending therefrom, the first depending tabs defining a first set of the slots; and the second inner surface includes a plurality of second depending tabs depending therefrom, the second depending tabs defining a second set of the slots.

25. The furnace of claim 24, wherein: the first and second depending tabs are integral with the central inner hub; and the first and second depending tabs are tapered in a direction moving away from the central inner hub.

26. The furnace of claim 25, wherein: each locking collar includes a skirt surrounding the rotatable shaft, a flange extending away from the skirt, and the fingers; and the fingers extend away from the flange in a direction opposite to the hub.

27. The furnace of claim 26, wherein: the fingers taper in a direction moving away from the flange.

28. The furnace of claim 27, wherein: each of the fingers include a tab extending therefrom, and each of the tabs abuts a side of the central inner hub of the roller.

29. The furnace of claim 28, wherein: the tab extends in a direction parallel to the direction of the flange.

30. The furnace of claim 16, wherein: the rotatable shaft is hollow.

31. The furnace of claim 16, wherein: the roller assemblies extend obliquely to a line perpendicular to the direction of travel of the billet.

32. The furnace of claim 31, wherein: the roller assemblies have an upstream driven and a downstream roller end, such that the rolling surface of the roller rotates and lifts the leading edge of the billet.