US1858484A - Conveyer - Google Patents

Description

May 17, 1932- w. B'COIOLEYV CONVEYER Filed May 22, 1929 5 Sheets$heet l attozmq Patented May 17, 1932 UNITED STATES PATENT OFFICE WILLIAM B. COOLEY, F MILWAUKEE, WISCONSIN, ASSIGNOR- TO HEVI DUTY ELECTRIC COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN CONVEYER Application filed May 22,

My invention relates'broadly to furnaces and more particularly to a furnace of the belt conveyer type.

v One of the objects of my invention is to provide a construction of furnace employing a belt type of conveyer for the heat treatment of small parts without containers therefor and without loss of heat from the conveyer. 7 Another object of my invention is'to provide means for controlling the movement of the conveyer in a heat treatment furnace where special provision is made to prevent distortion and abrasive wear of the conveyer belt.

Still another object of my invention is to provide a construction of conveyer type furnace where roller members are provided to relieve the strain upon the conveyer belt as a the conveyer moves material to be heat treated through the furnace.

A further object of my invention is to provide a construction of mounting for the conveyer belt in a heat treatment furnace whereinboth the upper and lower moving portions I of the belt may be supported to relieve the strain on the belt and prevent distortion of the conveyer belt under conditions of continued use.

A still further object of my invention is to provide a: system for driving an endless belt conveyer which is disposed wholly within a heat treatment furnace, with means for moving the belt through the furnace with minimum loss of heat while preserving the belt conveyer against strain under conditions of load to which the belt conveyer may be subjected.

Other and further objects of my invention reside in the construction of conveyer belt for heat treatment furnaces as set forth more fully in the specification hereinafter followingby reference to the accompanying drawings, in which:

Figure 1 is a side elevation of a heat treatment furnace showing the drive system for the rollers which operate simultaneously with the movement of the belt conveyer; Fig. 2 is a fragmentary plan view of the drive system for the rollers and belt conveyer in the n heat treatment furnace of my invention; Fig.

1929. Serial No. 365,122.

o is an end view of the heat treatment fur-, nace to which the conveyer system of my invention is applied; Fig. 4; is a lateral crosssectional view taken through the furnace structure on line l4= of Fig. 5; and Fig. 5 is a longitudinal sectional view taken through the heat treatment furnace and showing the belt conveyer system diagrammatically in cross-section.

Here-tofore in the art it has been customary to employ so called roller bottom furnaces as a conveyer where the driven rollers receive pans or trays containing small parts for heat treatment within a furnace structure. Llnk or woven belts have been used for the same purpose where parts of the charge, unless in pans or trays, would fall through the mesh or weave of the belt. The lighter weight belt preferably used in my invention,

may be made with a mesh sufiiciently fine as to prevent small pieces, such as lock-washers, set screws, etc, falling through the belt. The use of such containers causes unnecessary loss of heatdue to the necessity of heating the trays which do not form part of the furnace product. WVhere conveyers of the link or woven belt type, carrying the parts to be treated, have been used in heat treatment furnaces, the tension applied to the belt, in order to render the belt effective as a conveyer,

has resulted in distortion and also abrasive wear on the underside of the belt where it slides over the furnace bottom. This causes unnecessarily frequent replacement of the belt.

In the conveyer system of my invention I overcome the disadvantages heretofore eX- perienced in the art, by providing a continuous belt or conveyer of less weight than heretofore required, and I support the belt at a plurality of intervals between the driving drums over which the belt passes by means of rollers which are simultaneously driven, the movement of the rollers being coordinated with the movement of the conveyer belt for the passage of material under heat treat ment through the furnace. I also provide driven means which serve to support the lower portion of the conveyer during the return cycle of the conveyer to further relieve the strain upon the conveyer and improve the operation thereof.

Referring to the drawings in more detail, reference character 1 designates a typical heat treatment chamber formed by walls 2 which may be of fire brick which is surrounded at the top, bottom and sides by heat insulating material 3, which is in turn enclosed by a steel shell 4 having cast iron heads 5 closing opposite ends of the furnace. At the front end of the furnace I provide a heat insulated door 6 slidably arranged to be moved by suitable means to different vertical positions to allow insertion into the furnace of various sized articles to be heat treated and to permit the heat treatment chamber to be closed whenever required. At the opposite end of the furnace, I provide a rear door 7 which may be heated by suitable means, such as electrical elements represented at 8, this door 7 being intended for any emergency use. The furnace chamber may be heated by any suitable means, and for the purpose of explaining my invention, I have shown the furnace electrically heated by heating elements 9 diagrammatically illustrated as mounted in the top, sides and bottom of the furnace chamber. In mounting the heating elements on the top and side walls of the furnace chamber, I prefer to employ the type of heater element mounting set forth in copending application Ser. No. 279,810, filed May 22, 1929, by Edwin L. Smalley.

I provide a multiplicity of power driven rollers 10 which have shafts extending laterally through the furnace chamber and through the walls thereof in the same horizontal plane, which rollers serve to support a suitable endless belt 11 which may be of woven or link construction. The belt 11 passes over the driving drums or rotary cylindrical members 12 and 12a and over the several rollers 10 and is driven and supported by the coordinated operation of the driving drums and rollers. The belt 11 is relatively slack and when loaded the belt forms into catenaries between the rollers. These catenaries form undulations so that any one transverse section of the belt proceeds through the furnace in wave-like projection. This wave-like motion causes a slight tumbling action to small parts of the charge on the belt. This action is suificient to prevent adjacent parts of the charge being constantly in one contact with respect to each other during the travel of the parts through the furnace.

It is a well recognized condition that small parts, when otherwise progressed through furnaces, are apt to freeze together due to any cause such as a slight formation of scale bridging from one piece to another. This has existed to such an extent when heat treating small flat pieces with the flat faces in contact and ushing a mass of such pieces through the urnace as to cause such a freezing of pieces as to require a knockoff device at the discharge point, to break up such contact. The rear side of the belt in its return passage is supported by means of pulleys or drums l3 and 13a, the latter drums being carried on shafts 14 and 15, respectively. All the rollers 10, driving drums 12 and 12a and drums 13 and 13a, are simultaneously driven. Drums l2 and 12a are preferably so spaced from each other that the catenary 12b of belt 11 is sufficient to take up any elongation of the belt, as results from heat expansion. In some cases I may impart all of the necessary driving power by means of rollers 10, and in suchcases, therefore, use drums 12, 12a, 13 and 13a as idlers.

In order to provide for the coordinated operation of the several drums and rollers, I provide driving shafts 16 and 17 which are mounted in bearings 18 for rotation in opposite directions by means of bevel gear 19 and bevel pinions 20. Power is supplied to the bevel gear 19 through main shaft 21 which carries the bevel gear 19. Any suitable source of power may be utilized, such as an electric motor with suitable worm or spur gear speed reduction means and variable speed transmission means between the bevel gear 19 and the power source.

The shaft 16 carries a sprocket 22 which drives sprocket member 23 by means of chain 24. The sprocket 23 is mounted on the extension of the shaft of one of the horizontally disposed rollers 10. The direction of rotation of the rollers as governed by'the movement of the sprocket 22 is as indicated by the arrows of Fig. 1 of the drawings. All of the rollers 10 are interconnected and are driven by means of chains 30 and 31 which are looped over sprockets 32 and 33 carried by the extensions on the shafts of adjacent roller members 10. In order to provide for sufficient clearance of each of the looped chains 30 and 31 the sprockets 32 and 33 are offset in different vertical planes, as illus trated in Figs. 2 and 3. j

Shaft 17 carries sprocket 25 driving sprocket 26 by means of chain 25a. Sprocket 26 is carried by the shaft 15 which extends from the drum 130 which supports the lower side of the conveyer 11. Shaft 17 also carries sprocket 36 which drives chain 38 to impart movement to sprocket 37 which is positioned upon the shaft 14 on which drum 13 is mounted. The power for driving the conveyer through the furnace is delivered to drums 12 and 12a by means of chains 29 which engage sprockets 27 and 28, and additional conveying power is imparted to belt by rollers 10 as heretofore described. Sprockets 28 are carried upon the shafts 42 and 43 of drum 12 and 12a and are interconnected by the looped chain 29 with the sprocket 27 on the extension of shafts 10 of the second rollers from the end of the set of rollers constituting the conveyer within the furnace structure.

All of the shafts are journaled in suitable bearings which I have represented generally at 44 secured in the steel shell a, or otherwise suitably mounted.

The diameter of driver and driven sprockets in all cases is such that the perimeter speed of rollers 10, drums 12 and 12a and drums 13 and 13a are uniform throughout, thereby transmitting uniform speed of progression to belt 11.

Reference character 34; indicates a loading shelf supported on brackets 48 on the outside of the furnace, preferably having upturned flanges 35 at the side edges of shelf 3-l to guide particles of the charge onto the conveyer belt 11. Material deposited on shelf 34: may be either pushed manually along shelf 34: onto belt 11 or a pusher mechanism familiar to those versed in the art may be provided. Furthermore, shelf 3 L may be placed at an incline, where it would be possible to distribute particles from a conveyer belt onto the incline of shelf 34 and thereby automatically load parts onto belt 11.

Any suitable means at the discharge end of belt 11 may be provided, as for example, chute 39, which may discharge by gravity into any receptacle, as for example, an oil quench tank shown at 40, and preferably with discharge end of chute 39 below the level of liquid all.

In the operation of the conveyer system of my invention it will be noted that sliding friction on the underside of the conveyer belt has been eliminated, thereby reducing wear upon the belt. It will be noted that the conveyer is wholly within the heat treatment chamber of the furnace and conveyer loss of heat is prevented. By supporting the belt at a multiplicity of intervals by the plurality of rollers 11, distortion of the belt beyond the natural catenaries and undulations is prevent ed, so that an unevenly distributed charge on the belt will not produce undesirable belt tension for elongation of the belt parts. Sliding of the conveyer over the hearth of the furnace is prevented by means of drums 13 and 13a, and wear upon the conveyer is thereby substantially eliminated. By reason of the reduction in tension in the belt a sub- 5 stantially lighter weight belt, which is therefore more economical, may be utilized than in a belt otherwise driven, which must be of sufficient strength to carry the weight of the entire charge, plus the resulting tension stresses.

I have found the combined belt and roller type of conveyer as described herein very practical in its construction and successful in its operation.

While I have described a preferred embodiment of my invention, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

lVhat I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a heat treatment furnace of the conveyer type a heat treatment chamber, an endless belt conveyer mounted for movement wholly within said heat treatment chamber and a plurality of rollers members spaced at intervals along the length of said conveyer and within said chamber for supporting the under surface of said conveyer and providing means for advancing charges through said heat treatment chamber during the process of heat treatment, and means for imparting motion simultaneously to said roller members and to said endless conveyer, discharge means below one end of said conveyer and a removable door in the end of said chamber above said discharge means for affording access to the charges on said conveyer.

2. A heat treatment furnace comprising a heat treatment chamber, an endless conveyer mounted to move wholly within said heat treatment chamber from the receiving end of said chamber to the discharge end thereof, electric heating elements surrounding said conveyer throughout the course of movement thereof, a discharge chute extending from the discharge end of said conveyer within said chamber to a point exterior-1y thereof, and a removable door adjacent the discharge end of said chamber and aligned with the plane of the upper portion of said conveyer, said removable door having electric heating elements thereon for subjecting charges on said conveyer to heat at the discharge end of said heat treatment chamber.

In testimony whereof I afiix my signature.

WILLIAM B. GOOLEY.

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