US2448514A

US2448514A - Heat-treating machine

Info

Publication number: US2448514A
Application number: US584549A
Authority: US
Inventors: William F Butler
Original assignee: American Can Co
Current assignee: Primerica Inc
Priority date: 1945-03-24
Filing date: 1945-03-24
Publication date: 1948-09-07
Anticipated expiration: 1965-09-07

Description

Sept. 7, 194& w. F. BUTLER HEAT TREATING MACHINE 2 Sheets-Sheet 1 Filed llarch 24, 1945 P 7, 1948. w. F. BUTLER 2,448,514

HEAT TREATING MACHINE Filed larch 24, 1945 2 Sheets-Sheet 2 Patented Sept. 7, 1948 HEAT-TREATING MACHINE William F. nuns Hillside, n. 1., auignor to -American Can Company, New Yon-Lit! a corporation of New Jersey Application March 24, 1945, Serial No. 584,549 4 Claims. (01. 34-119 The present invention relates to a machine for heat treating sheet material and has particular reference to devices for flexing the sheet material during the heat treatment to insure more uniform and rapid treatment.

In recent years heat treating sheet material as by heating or cooling has been greatly accelerated and has led to so called "flash" methods which have become of great importance, in the can making industry for example, since such method of rapid treatment facilitates the preparation ,of materials in accordance with the high speed rates of production which are now required. In these methods, the heat treatment is applied directly to the material being treated and in some variations by direct contact with heat treating elements so that heat is transferred by conduction from one to the other.

In the rapid heat treatment of sheet material uneven heat transfer usually takes place throughout the area being treated thereby setting up uneven expansion strains which warp the material out of shape or which form islands or bulges in the material. This is occasioned by the impossibility of bringingall parts of the sheet material, especially when one surface is coated and wet, into engagement with the heat treating element so that every minute area of the material will contact with the treating element at the same time. It has been found that the portions of the material that contact the treating element will expand or contract differently than those which do not and it is this uneven expanother of the elements to bring about a more uniform treatment of the material.

An object of the invention is the provision of a heat treating machine for sheet material'wherein the material being treated is flexed in one direction and then in another direction to snap.

out of position any temporary distortion of the material so that any warped areas or islands, or the like caused by unequal expansion or contraction is eliminated to the end that heat treatment of the material by direct contact and heat conduction may be eilected uniformly throughout the material. I Another object is the provision of such a machine which is adapted for sheet material having a freshly applied coating on one surface, wherein the heat treatment of the sheet material is eifected by rotary treating elements engageable only with the uncoated surface of the material and arranged in such a manner as to effect flexing of the sheet material as the latter passes over them.

Another object is the provision of a machine of this character wherein the rotary treating elements are provided with means for insuring direct engagement with the material throughout its area so treatment of the material will be facilitated.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings,

sion or contraction that sets up the strains in the I material and thus brings about its warping or the formation of islands.

Where such heat treatments are utilized to dry lithographing or other coating substances on the sheet material; it has been found that a longer drying period is required to dry the warped sections and the islands than is required for the remainder of the material. Thus when the drying time is set not to exceed a predetermined period as in rapid flash methods, the materialis often discharged from the machine with wet spots which during subsequent handling smear or rub off and hence render the material useless for the purpose it was originally intended.

The instant invention contemplates overcoming these diiliculties by the provision of a machine. having rotary heat treating elements arranged so as to flex the sheet material as it passes from one element to the other, thereby requiring any temporarily distorted spots in the material being brought into engagement with one or the discloses a preferred embodiment thereof.

Referring to the drawings: 7

Figure 1 is a top plan view of a heat treating machine embodying the instant invention, with parts broken away and with sheets of material to be treated in place in the machine;

Fig. 2 is a longitudinal vertical section taken substantially along the line 2-4 in Fig. 1, with parts broken away and showing sheets of material passing through the machine;

Fig. 3 enlarged transverse vertical section taken substantially along the line 3-3 in Fig. 1,

and showing one of the heat treating elements and a sheet of material in section;

Fig. 4 is an enlarged fragmentary portion of a heat treating element as in Fig. 3 and showing a relatively small warped portion of a sheet of material in engagement with the element;

Fig. 5 is an enlarged sectional detail showin three of the heat treating elements of Fig. 2 and also showing a sheet of material being treated and flexed thereby; and

that more efilcient heat conduction 'Fig. 6 is a view similar to Fig. 2 but showing a modified form of the invention.

In considering the subject of heat treatment of sheet material it should be understood that the instant invention is equally well adapted to the treatment of individual sheets or strip stock of any flexible material and for the purposes of this specification the broad term sheet material is intended to cover individual sheets as well as strip stock or other form of material.

The invention is also equally well adapted to negative heat treatment as through a cooling action in which the temperature of the material is reduced. or to a positive heat treatment as through a heating action in which the temperature of the material i increased and for the purpose of this specification the broad term heat treatment is intended to cover cooling as well as heating of the material. I

As a preferred embodiment of the instant invention the drawings illustrate a machine for treating or cooling individual sheets A of tin plate as they are delivered in a continuous procession from a conventional baking oven 3. The sheets as they are delivered from the oven have one surface covered with freshly applied lithographing or other coating substance in a partially dried or baked but still in a tacky condition. The cooling of the sheets sets the coating and renders it hard so that the sheets may be stacked for subsequent handling.

The hot sheets as they are delivered from the oven are often warped because of unequal expansion strains in the sheet. This warped area of the sheet sometimes forms elongated raised areas such as designated by the letter C in Fig. 1. More often islands ,of different sizes of raised or depressed areas, designated by the letter D are formed in the sheet. The amount of distortion of these areas from the plane of the sheet may be inilnitesimally small in some cases as compared with the size of the sheet but in all cases the material of the sheet in these areas is displaced from the plane of the sheet and is dimcult to cool rapidly as required by the Flash method wherein speed of treatment i highly essential. It is to the treatment of these displaced areas that this invention is especially directed.

The hot sheets A are delivered from the baking oven B in a horizontal position with the coated surface up and the uncoated surface resting on an endless belt conveyor ll (Figs. 1 and 2) which receives the sheets from the usual oven conveyor. The belt conveyor ll operates over a driven pulley l2 mounted on ashaft l3 iournaled in bearings I 4 formed in a pair of side frames II which constitute the main frame of the treating or cooling machine.

The belt conveyor ll delivers the sheets to the cooling machine which includes a plurality of cooling rollers or heat treating elements II on which the sheets are received and conveyed through the machine. These rollers extend transversely of the machine between the side frames II and are arranged in parallel relation with each other. The rollers are hollow and are fitted with end closure members I! (Fig. 3) having hollow trunnions II which are iournaled in half bearings 22 formed in the side frames i5. Bearing caps 23 bolted to the top of the frames retain the trunnions in their bearings.

The outside diameters of all the cooling rollers I! may be the same dimension. However, as a preferred embodiment of the invention, the bearings of alternate rollers are shown in Figs. 2 and 4 5 as being elevated above the bearings of the in-between rollers. This makes the tops of alternate rollers higher than the in-between rollers and thus produces an undulating effect on sheet material passing thereover. v

The rollers II are continuously rotated in the same direction (a clockwise, direction as viewed in Fig. 2) by spur gears 26 (Fig. 1) respectively mounted on one of the trunnions of each roller. These spur gears mesh with intermediate gears I1 (see also Fig. 3) which are disposed one between each pair of spur gears. ears are mounted on stub shafts 28 carried in bearings ll formed in one of the side frames It.

The meshing spur gears 26 and intermediate gears 21 thus form a continuous gear train which extends along one side of the machine and which operates as a single unit so that all the cooling rollers ll rotate simultaneously in the same direction and at the same rate of eripheral speed. One of the stub shafts 28 is longer than the others and serves as a driving shaft for rotating the entire train. This shaft may be driven in any suitable manner. A gear 3| mounted on the sheet delivery belt conveyor shaft ll meshes with the adiacent intermediate gear 21 of the train and thus the conveyor is, driven in time with the cooling rollers.

Each of the cooling rollers I8 is maintained in a cooled condition by a fluid cooling medium 34 (Fig. 3) which is carried in the rollers. This medium is cooled by a pipe or tube 35 located in each roller. The ends of the tube extend through bushings 3| fitted in the hollow trunnions 2|. These tube ends project beyond the trunnions on each side of the machine and are connected by way of couplings I! and pipe fittings 38 to a fluid refrigerant supply pipe (I on one side and a refrigerant return pipe 42 on the other. These supply and return pipes lead from and to a suitable supply of the fluid refrigerant. The pipes are supported on clamp brackets 43 bolted to the side frames I! at intervals along the length of the machine.

A magnetic field is maintained across the full length of each of the cooling rollers is for attracting the sheets to the rollers. These magnetic fields are created by a plurality of stationary permanent magnets 45 (Figs. 2 and 3) disposed one within each of the cooling rollers although electromagnets may be used if desired.

The magnets 48 preferably are of the one piece, elongated. horse shoe type although a plurality of shorter magnets disposed end-to-end and properly supported may be used if desired. In the drawings the magnet in each roller is disposed close to the inner surface of the roller and is located in the upper portion of the roller adjacent the path of travel of the sheets. These magnets are supported at their ends on shelf-like extensions ll of collars 41 which surround and are clamped onto the cooling pipes 35.

Hence as a hot sheet of the plate A is delivered by the conveyor II from the baking oven B to the cooling machine, it is received on the rotating cooling rollers l8 and is propelled by the rollers the full length of the machine to its discharge end where it is discharged to any suitable place of deposit. During this travel of the sheet through the machine, the magnets within the rollers pull the sheet down into contact with the upper portions of the outer peripheral cooling surfaces of the rollers. This contact of the sheet with the rollers facilitates rapid cooling of the The intermediate sheet material, the heat rapidly passing by conduction into the rollers and quickly setting and hardening the coating substance on the upper surface of the material.

As a sheet progresses through the machine and passes from one roller to the next, it moves along an undulating path of travel. Portions of the sheet thus shift from one level to a higher 'or lower level of the adjacent roller. This flexes the sheet at the points marked by arrowsin Fig. 5, first in one direction and then in an opposite direction as it advances from roller to roller. This flexing of the sheet tion any temporary distortions such as the raised or depressed areas 0, D hereinbefore mentioned. Such flexing has the, effect of turning the restricted areas inside out so that they shift for example from a position as shown in Fig. 3, where they do not engage a roller surface, to a position as shown in Fig. 4 where they do engage an adjacent roller surface. i

In this manner as the sheet advances from roller to roller the flexing action definitely brings the distorted areas C, D into direct contact with the cooling surfaces of the rollers and thus cools these areas of the sheet just as rapidly as the other portions of the sheet. This substantially simultaneous cooling of all portions of the sheet relieves theexpansion strains concentrated at the distorted portions and hence these distorted areas are dissipated rapidly with the result that the cooled sheet is just as flat, as before its introduction into the heating oven. Moreover, the flexing of the sheet by forces applied from one surface only, the uncoated surface in this case because it will be recalled the opposite surface is wet and tacky, has the advantage of removing the distortions without imparting a permanent set to any portion of the sheet. This setting sometimes results when a pressurels applied to both sides of the sheet in its distorted condition.

In the drawings the axes of the rollers are shown in fixed position. Obviously even greater flexing could be obtained if desired by moving the rollers up and down while the sheet is passing over the same.

In the modified form of the invention as illustrated in Fig. 6 the belt conveyor ll delivers the sheets to be treated onto a plurality of axially aligned alternately small and large diameter cooling rollers or heat treating elements 5|, 52 respectively. These rollers are arranged alternately in a row, the large rollers 52 being disposed between the smaller rcllers 5|. The rollers are mounted on rotatable trunnions 53 which are disposed in thesame horizontal plane; The trunnions are journaled in bearings in suitable side frames similar to the side frames l5 and are rotated by'a gear train in the same manner as explained above for the preferred form of machine. The rollers Si, 52 are of the same construction and are cooled in the same manner as in the instance of the preferred form of the invention and are equipped with the same magnets for drawing the sheets into engagement therewith.

In the modified form of the invention, it is the large and small size of rollers thatproduc'es the undulating path of travel along which the sheets to be treated pass. The sheet contacting surfaces of theselarge and small rollers in the path of snaps or springs out of posiportions into positions to contact the rollers so that all portions of the sheet including any distorted non-contacting areas are insured full contact with the rollers for rapid and uniform heat treatment throughout.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, audit will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim: 1. A machine for heat treating flexible sheet material, comprising a plurality of horizontally spaced hollow rotatable rolls having cylindrical heat conducting surfaces substantially tangenmoving sheet material, magnetic means on the travel of the sheets are disposed at different heights and thus the sheets are flexed first. in one direction and then in the opposite direction as they pass from flexing of the sheets that snaps their distorted one roller to another. It is this tially engageable at their upper portions only with the moving sheet material, magnetic means on the interior of each of said rolls for holding the sheet material against the upper surfaces of the rolls, means for supporting and rotating the rolls with their sheet engaging surfaces relatively vertically spaced transversely to the direction of travel of the sheets to deflne an undulatorypath of sheet travel so as to flex the moving sheet material, and means for imparting a predetermined temperature to the heat conducting surfaces of said rolls.

. 2. A machine for cooling heated flexible sheet material, comprising a plurality of horizontally spaced hollow rotatable rollers of substantially equal diameter mounted on relatively vertically spaced axes, saidrollers having relatively vertically spaced cylindrical heat conducting surfaces engageable at their upper portions only with the moving sheet material, magnetic means on the interior of each of said rollers for holding the sheet material against the said upper surfaces of the rollers, means for supporting and rotating the rollers with their sheet engaging surfaces disposed in staggered relation transversely to the direction of travel of the sheets to define an undulatory path of sheet travel so as to flex the moving sheet material in opposite directions, and means for cooling the heat conducting surfaces of said rollers.

3. A machine for cooling heated flexible sheet material, comprising a-plurality of horizontally spaced hollow rotatable rollers of varying diameters mounted on substantially horizontally aligned axes, said rollers having relatively vertically spaced cylindrical heat conducting surfaces engageable at their upper portions only with the interior of each of said rollers for holding the sheet material. against the said upper surfaces of the rollers, means for supporting and rotating the rollers with their sheet engaging surfaces disposed in staggered relation transversely to the direction of travel of the sheets to define an undulatory path of sheet travel so as to flex the moving sheet material in opposite directions, and

means for cooling the heat conducting surfaces of said rollers. 7

4. A machine for heat treating flexible sheet material, comprising a plurality of horizontally spaced hollow rotatable rolls having cylindrical heat conducting surfaces substantially tangentially engageable with the moving sheet material, magnetic means associated with said rolls for holding the sheet material against said roll sur- 7 faces, means !or supporting and rotating the rolls with their sheet engaging surfaces relatively vertically spaced transversely to the substantially horizontal direction. of travel or the sheets to define an unduletory path or sheet travel so as to flex the moving sheet material. and means for imparting a predetermined temperature to the heat conducting surfaces of said rolls.

WILLIAM F. BUTLER.

REFERENCES CITED The following references are of record in the tile of this patent:

Number UKI'I'ED STATES PATENTB Home Data Palmer Aug. 20, 1889 Spencer May 19, 1914 Tompkins Apr. 11, 1916 Elmendorr Feb. 16, 1926 Holcomb Apr. 19, 1932 Edwards July 7, 1936 Eberhart Mar. 3, 1942 Eberhart Mar. 17, 1942 Miller June 27, 1944 Butler Dec. 26, 1944 Butler May 29, 1945