US2306448A

US2306448A - Sheet making apparatus

Info

Publication number: US2306448A
Application number: US354643A
Authority: US
Inventors: Edouard M Kratz
Original assignee: Kraft Cheese Co
Current assignee: Kraft Cheese Co
Priority date: 1939-05-19
Filing date: 1940-08-29
Publication date: 1942-12-29
Anticipated expiration: 1959-12-29

Description

Dec. 29, 1942. E. M. KRATZ SHEET MAKING APPARATUS Original Filed May 19, 1939 5 Sheets-Sheet l fizz/072207 HY. r v nu NQN mg www d Dec. 29, 1942. E. M. KRATZ SHEET MAKING APPARATUS 5 Sheets-Sheet 3 Original Filed May 19, 1939 Dec. 29, 1942.

E. M. KRATZ 2,306,448

SHEET MIAKIING APPARATUS Original Filed May 19, 1939 5 Sheets-Sheet 4 I m HM H IHHI 13. 29, 1942. E. M. KRA Ti 2,306,448

SHEET MAKING APPARATUS Original Filed May 19, 1939 5 Sheets-Sheet 5 l U 2 72 I a I lziuanzor l?- jdoaaadfl z Patented Dec. 29, 1942 UNITED STATES; PA E T OFFICE: 7

SHEET mi trrmrus p Edouard M. Kratz, Ogden Dunes, Ind, assignor to Kraft Cheese Company, Chicago, 111., a corporation Delaware Ori a 6 Claims.

This invention relates to apparatus for making webs or sheets and this application is adivision of my co-pending application Serial Number The main objects of this invention are to provide mechanism which will facilitate the production of sheets or webs of uniform thickness; to

.provide mechanism Ior'automatically controlling the operating condition 01 mechanism which is subject to variation due to. various causes, including changes in temperature; and in general, to

- provide improved apparatus for the purpose set forth.

- Other objects and advantages or the invention will be understood by reference to the following specification and accompanying drawings (live 1 application May 19, 1939, Serial No. Divided and this application August 29, 1940, Serial No. 354,643 I y catenary curve of -an elongated sheet forming belt 26. The belt is, in this instance, 01' stamless steel orthe-like having a highly polished orplated outer surface and the belt is supported at .its oppositeends by

rollers

21 and 28. The roller 21 is the receiving end or the machine to which 1 the composition is delivered to the belt for tormsheets) wherein there is disclosed the improved apparatus or the character indicated. 1

In the drawings: Fig. l is a diagrammatic representation of the improved sheet forming apparatus;

' Figs. 2, 3 and 4 are more or less diagrammatic illustrations on an enlarged scale of various por-v tions of the apparatus as shown in Fig. 1;

Fig. 5 is a side elevation, of mechanism for automatically controlling the tautness and curling of a drying belt;

ing the sheet and the roller is adjustably mounted so as to permit adjustment or the tautness of the belt, so that itsicatenary curve may be maintained substantially constant, notwithstanding changes in the length or the belt due to expansion or contraction. "I'hesheet formed on the belt is delivered from the lower reach of the belt and wound on suitable'reels near the receiving end or the machine by suitable mechanism indicated generally at- 29. v

The means for delivering the composition to the receiving end of the machine, and the means for spreading and controlling the depth thereof on the belt forms no part of the subject matter claimed in this application and is, therefore, not

Figs. 6, I and 8 aresections, respectively, on

the lines 6-6, 1-1 and 8-4 of Fig. 5;

Fig. 9 is an elevation of electrical switch mechanism forming a part oithe apparatus;

Figs. 10, 11 and 12 are sections, respectively, on the lines Ill-40, ll-ll and l2-l2oi Fig. 9;

Fig. 13 is a plan of the rear end portion "0: the

being passed through an oven and in any instance where uniformity of thickness is diillcult of achievement because of. a normal tendency oil.

the material from which the sheeting is formed to flow or run on the forming belt. v The apparatus herein shown comprises an elongated oven designated in its entirety25, the same being preferably built to match the normal illustrated or described, but the same is fully disclosedin my said. co-pending application.

The oven 25 is supplied with hot air through suitable inlets and by. suitable mechanism as more fully explained in my co-pending application Serial No. 229,509 and suitable outlets and connections to permit recirculation of the air are, or course, contemplated. Inasmuch as these are rully explained in mysald co-pending application they will not be detailed herein. 2

The belt supporting roller 28 at the rear end oi I the apparatus is iournalled in suitable bearing brackets 61 which are suitably slidably mounted on "side frames 82. By adjusting the roller 28 toward or from the drum 2! at the front end of the apparatus, the tautness and position of the belt 26 within the oven 25 may be controlled. Such adjustment may be effected either manually or by power means. For this purpose there is pro-. vided in association with each of the slidably mounted bearing Ii, a screw threaded rod 63 which is suitably connected at one end to the slidable bearing member I or to the shaft of the roller 28 adjacent the slidable bearing ll. The screw threaded rod 63 threadedly engages an internally threaded, elongatedsleeve which comprises an intermediate enlarged portion 65 andendwiseextensionsiii and 61.

, The endwise extension 66 is :lournalled in a bearing 68 formed integrally or rigidly secured in fixed position on the adjacent side frame 62. A collar 69 pinned or otherwise secured to theextremity of the sleeve-portion 65 serves to prevent withdrawal of said sleeve portion from the bearing 88 and a suitable anti-friction bearing 18 is interposed between the enlarged portion 85 and the adjacent end of said bearing 88. The other sleeve extension 81 has keyed to it a miter gear 1| which has rigidly connected to it a hand wheel 12. The miter gear 1| is adapted to be rotated manually through the agency of the hand wheel 12 to thereby turn the threaded sleeve to effect longitudinal movement of the screw threaded rod 83 and thereby adjustment of the roller 28. I

For effecting such adjustment by power means, there is provided an electric motor 13 having a suitable belt or-other driving connection with a suitably journalled shaft 14, which carries a worm gear 15. The worm gear 15 meshes with a worm wheel 18 which is carried by a suitably journalled shaft 11 and the shaft is equipped at its opposite ends with miter gears 18, 18 which mesh with the respectively adjacent miter gears 1|. It will be apparent that when the electric motor.18 is energized, the shaft 11 will be driven and the screw threaded rods 83 caused to move forwardly or rearwardly in accordance with'the rotation imparted to the threaded sleeves by reason of the miter gear connections 1| and 18.

If desired or needed for positively preventing disengagement of the gears 1 I and- 18 when power is applied to the latter, there may be provided suitable means such as stop screws I88, threaded through the collar which is pinned on the outer end of each sleeve extension 81, for engaging the outer end of the hub of the miter gear .1 I. The electric motor 13 is of the reversible type so that it may be selectively actuated in both directions to' effect either forwardorrearward adjustment of the roll 28. Normally, it is desired to effect uniform adjustment of both ends of-the roll 28 so as to maintain the normal parallelism of the roll 28 with the front end roll 21.

However, occasionally, as for example when in stalling a new belt 28, it is advantageous if either side of the roll 28 may be adjusted independ-- the alternative, the side of the roll corresponding to the disengaged gears 1| and 18 may be manually adjusted through the agency of the hand wheel 12. Such manual adjustment isfacilitated when the gears 1| and 18 are disengaged, since by breaking the driving connection that on the upper reach'of the belt the sheet is located on the upper surface thereof and that on the lower reach of the belt the sheet is on the lower surface thereof. Under these circumstances the upper reach of thebelt may be supported from below by means of suitably journailed rollers 88 disposed at such locations as experience shows to be most desirable. In Figures 2, 3 and 4 of the drawings, such supporting rollers are indicated at spaced intervals throughout the length of the oven. Each of the rollers 88 -may be supported on a shaft such as 88 (see Figs.

5, 8 and 8) which is suitably supported by means of brackets indicated at 88 forming a part of or secured to the oven frame work.

Associated with each of the supporting rollers 83 are grooved

rollers

88, 88 journalled on a bracket such as indicated at 81, supported from a bearing member 88 on the shaft 84. Each roller 81 receives in its peripheral groove an edge portion of the belt 28 (see Figures 5 and 6) and thereby serve to maintain the belt flat and in engagement with the roller 88 across the entire width thereof. By this means the normal tendency for the belt to curl transversely is overcome. By thus maintaining the belt flat (and in a substantially horizontal plane), there is no tendency (or at least only a negligible one) for the sheet forming liquid to run on the belt. Hence, the production of sheeting of uniform thickness is facilitated. The bracket 81 is preferably pivotally mounted intermediate its ends on the bearing 88, :so that the bracket arm 81 may pivot sufficiently-to permit the rollers 88 to bear equally of the belt is of less importance than of the uppe reach, since the sheet is well set by the time the sheet forming material, reaches the rear end of the belt and begins its return travel on the lower reach thereof.- However, I have found that control of the lateral position of the belt.

or in other words, control of migrating tendencies of the belt, may be advantageously effected by action on the lower reach of the belt. Pref- -movement cross-wise of the receiving end of between the gear 1| and the gear 18 no part of themanual force applied to the handwheel 12, would be transmitted to the shaft 11 and motor 13. sleeve may advantageously be provided with graduated scale markings indicated at' 18 for cooper-' ation with a pointer carried by the adjacent bearing 88 to facilitate measured adjustment of the screw 83 and corresponding end. of the roll 28.

The roll 28 and the described adjusting mechanism are housed in an enclosure-indicated at 8| (Figures 1, l3 and l4),'-the same being connected to the oven 28 by

suitable passageways

82, 82 for the upper and lower reaches of the belt 28. Inasmuch as the sheet is formed on the outside surface of the belt 28. it will be understood The central enlarged portion 85 of each the drum 21, which limits are somewhat less than corresponding limits on the roll 28 at the rear end of the apparatus.

The mechanism for controlling the belt by action on its lowerreach comprises a pair of

rollers

88, 88 which extend transversely over and in engagement with the upper surface of the lower reachof the belt 28. Said

rollers

88, 88

are equipped with endwise' extending shafts which are joumalled in

suitable bearing members

88, 88 to which are connected angle iron side members 8|, 8|. The angle iron side members 8| are thus supported by the lower reach of the belt 28 through the agency of the rollers spect to the switch gang 99.

2,809, ment with the surface of the

rollers

99, 99 across their entire lengths.

The position of the supporting rollers 99 and of the edge engaging rollers 99 in the direction extending transversely of the widths of the oven 25 is fixed by means of a frame 94 which has a transversely extending bar 99 pivoted at its ends to the adjacent side members 9| approximately mid-way between the ends thereof. The said frame 94 also has a transversely extending member 99 pivoted at its opposite ends to the walls of'the oven as best shown in Figure 7, so as to prevent shifting of the frame transversely of the oven chamber. By the same token, the roller supported. side members 9| are prevented from shifting transversely and hence, through the edge engaging rollers 93, serve to maintain the belt in a substantially fixed path of travel.

Incident to temperature changes in the oven, especially when first commencing the operation of the apparatus and when stopping the same, the conveyor belt 29 expands or contractsto such an extent that the vertical position'of the reaches of the belt may vary considerably. Most of such variation is reflected in'the lower reach of the by the transverse rollers 93. The extent of change in the length of the belt upon expansion is sumcient to cause the lower reach of the belt to very closely aproach the bottom of the oven chamber'unless the chamber is made be controlled by means of rock levers I99 and I99, respectively, which are pivotally mounted on a common pivot pin WI. The free ends of the arms I95 and I99 are equipped with upwardpivoted switch-supporting bracket members I99.

and "II, respectively. Said extensions are also bent was to provide shoulders I II which extend transversely across the adjacent end flange of the respective members I99 and M]. It will be seen that as an incident to rocking movement of the arms I99 and I99, the corresponding extension I99 or I99 will, on upward movement of the free end of the arm, engage and move the outer side of the overlying switch-supporting bracket I99 or IM upwardly so as to cause the mercury'content of the respective switch tubes to fiow to the other end thereof, to thereby close belt since the upper reach is positively supported much larger. than is desirable for efliciency in closely-enough to the bottom of the. oven to either touch the same or, pick up'dust or other foreign matter from, the bottom of the oven chamber merely incident to the air currents induced by.the travel of thebelt. The vertical position of the lower reach of the belt may be controlled by' adjusting the. rearroller 29 to an electric circuit in a well known manner.

Similarly, when the upwardly moved arm I99 or I99 is restored to its initial position, the ear H9 at the upper end oi the upper extension will engage the top of the switch supporting bracket best shown in Figure 19, the arm I95 is equipped with a downwardly facing forked extension com prising a long arm 2 and a short arm H9.

take up the expanded length of the belt and thereby maintain the lower reach in a predetermined normal position between the top and bot tom of the oven chamber for the lower reach .of the belt.

' connected to the electric motor 13' which, when energized, efiectsradjustment of the rear or belt take-up roller 29.

As best shown in Figures 9 and-11, the switch mechanism 91 comprises two

gangs

99 and 99 of switch elements, in this instance mercury switch tubes, the same being mounted on suitable brackets I99 and-I9I, respectively, which are mounted for rocking. movement on a supporting pivot pin I92. As shown in Figure 9, the switch members are in oil-position, the mercury content of each switch unit being disposed in the outer ends of the respective switch tubes. The weight of the mercury content. of the switch tubes is sufllcient to maintain the tubes in their provided for supporting the switch units in their on-position as indicated indotted lines with re- The

switch gangs

99 and 99 are adapted to Similarly, the rock arm I9Ii is provided with a downwardly facing forked extension comprising a long arm I I4 and a short arm I I5. The forked extensions of the arms I99 and I99 cooperate with the upper end of a rock lever 9, which is secured at its lower. end to a rock shaft II'I suitably journalled in the'oven wall.- The rock with an-underlying member II9 of substantially the same shape and size as the arm N9, the member. I I9, however, being pivotally mounted on the shaft -I I1 instead of fixedly secured thereto as is the arm III. The arm I I9 is provided with a slot I I9 and the arm I I9 is provided with a threaded hole I29, forreceiving a clamping screw III which passes through the slot. II9 and is adapted to clamp the member- H9 in fixed position relative to the lever arm I- I9.

The rock shaft II! is provided within the ovenwith an arm I22 and the free end of said arm I22 is connected by means of a link I29 to the adjacent belt supported side. frame 9I'.- Hence,

. in the event that the belt expands and is lengthened, downward movement of the lower reach of the belt will produce a rocking motion in the rock shaft II'I. Such motion will be transmitted to' the rock arm III. Assuming, for example, thatv [the belt is lengthened so (as to cause rocking movement of the shaft III in a clockwise direction as shown in Figure 9, the rock arm II9 will also rockin a'clockwise direction so as to cause its free end to engage the lo'ng finger I ll of the forked portion of the rock lever I99, suchmovement thereupon causing the rock lever I99 to turn on its pivot I91 in a counter-clockwise direction. Incident to such. movement, theshoulder II let the outer end of the rocklever I03 will engage the switch bracket MI and when suillcient movement has been effected, the switch gang 99 will be adjusted to its on-position. The electric circuit controlled by the switch gang 99 is such that the motor 13 will be rotated in the proper direction to adjust the belt take-up roller 23 outwardly to thereby tighten the belt and" cause the lower reach thereof to be pulled upwardly t'owardits normal position.

As an incident to the restoration of the lower reach of the belt to a suitably elevated position, the rock shaft III is, of course, rotated in a counter-clockwise direction so as to permit lowering of the rock lever I06. A suitable spring I24 is provided for causing the rock lever I08 to follow the movement of the arm 9, and as an incident to the engagement of the lip IIO on the extension I09 of thelever with the switch supporting bracket IOI, said spring will ultimately restore the switch gang 99 to its initial or oil-position, whereupon adjustment of the belt take-up roller 28 ceases. It will be observed that when the upper end of the rock arm ".6 engages the finger II4 of the lever I09, the said upper end clears the arm II3 of the other switch lever I09 so that the switch gang 99 is not actuated. When the rock lever I09 is in an upwardly adjusted position, the shorter finger II5 of that rock lever is swung to a position in which it will be in the path of return movement of the arm 6. Hence, in the event that the spring I24 fails to eifect return movement of the lever I06, such movement will be effected by engagement of the arm H6 with the said shorter-finger H3 of the lever. A stop pin I29 is provided for limiting the downward or clockwise turning movement of the lever I06. A similar spring I24 and a similar stop pin I29 are provided in association with the other rock lever III for the same purpose.

Upon shutting down of the apparatus or cooling of the oven and hence cooling of the belt, and incident to shutting down of the apparatus for other reasons, the lower reach of the belt, incident to contraction, will move upwardly and through the described connections effect counterclockwise rocking of the shaft III. Under such circumstances, the arm 9 will actuate the rock lever I05 and the switch gang 99 to complete an electric circuit for causing the electric motor I3 to rotate in an opposite direction for effecting an inward adjustment of the belt take-up roller 23 to slacke'n the belt. The slackening continues until such time as the rock arm III has been returned to a position wherein the lever I03 willhave caused the switch gang 93 to be dropped a to an off-position, to thereby open the circuit to the electric motor I3.

A pair of oppositely positioned mercury switch tubes I25 and I21 may be advantageously mounted on the rock armJ I 9 so as to control electric circuits for signal lights which will indicate to an attendant of the apparatus. whether or not any distortion or other impairment oi the belt if not actual breakage thereof. 11' the adjustment were to continue in the other direction, the belt might The terminal carrying strip the oven with the result that the sheet forming suface of the belt might be scratched, dented, or otherwise impaired to such an extent that it may not even be possible to repair the belt and its replacement thus necessitated. In either event, the. damage may entail considerable loss not only in respect of the cost of the belt itself, but in respect of the labor required for installation and the loss of production during the time required for repair or replacement.

'For the purpose of preventing such a contingency, there is provided a safety device in the form of an electric switch indicated in its entirety at I23 (see Figures 5, 9 and 12), which switch, upon being opened, breaks the electric circuit to the motor I3 so as to prevent operation thereof to effect adjustment of the belt take-up roller 28 beyond predetermined limits.

The said switch I92 comprises a series of contact elements I29 which are fixedly mounted on an insulating base element I30 and respectively connected in the circuit wiresof the electric motor I3. A corresponding series of electrical terrninals I3I is carried by a strip I 32 of insulation material and respectively connected to the electric wires of said circuit as indicated in Figure 19. I32 is slidably mounted on the side legs I33,'I33 of a bail-like member I34 which is suitably anchored in the insulating material base element I30. A cam element I39 is mounted for rocking movement on the bail member I34 and acts against a saddle I33 which is carried by the slidably mounted terminal supporting strip I32. Inthe normal position of the cam I39 as shown in the drawings, the strip I32 is held in an inwardly disposed position, wherein its contact terminals I3 I are in engagement with theterminals I29 so as to maintain a circuit through said terminal elements. Suitable compression coil springs I31 are provided and normally tend to move the terminal carrying strip I32 outwardly so as to separate said contact elements tothereby open or break the electric circuit. v

The cam element I39 is adapted to be controlled by a push rod I33 which is slidably mounted in the oven wall. The inner end of the push rod I33 normally engages a recessed sur- The bar I40 is slidably mounted at its upper end in a slot I provided in an extension of the push rod guide element, and the lower end of the said bar is pivotally connected as shown at I42 to the adjacent side member I 43 of the frame 94.

- In the event that the frame 94 is caused to continue upward movement, for example, beyond a normal extent for effecting correction of the position of the lower reach of the belt 29, a cam surface I44 adjacent, the lower end of the recessed seat I39 in the bar I43 will engage and move the push rod I33 outwardly to thereby rock the cam I43 so as to permit the springs I3] to move the contact carrying member I32 outwardly, thereby breaking the circuit to the electric motor I3 and stopping'its operation, notwithstanding the continued' maintenancejof a closed circuit by the switch gang 93 or. 99. Similarly, in the event that the frame 94 continues downward movement beyond a predetermined limited extent, a cam surface I43 adjacent the upper end of the recessed seat I39 in the bar I49 will encome into scraping contact with the bottom of gage and move the push rod m outwardly to break the circuit to the motor I3.

The eflective control by means of the above described adjustable supporting means for the doctor blade of the depth of film of sheet formingliquid applied to thebelt, and the effective control or prevention of curling of the belt constitute important aids in the production of sheet material of uniform thickness throughout its width. The described controls are of relatively simple construction and they are not likely to get out of order, so that their eifectiveness is enhanced by their durability and efliciency.

The described mechanism for controlling tautness of the belt is also of considerable importance in apparatus of the type described in view of the improved results obtained when the sheet formed on the belt is dried under conditions which may be maintained substantially constant within the selected operating zone of the belt.

The said belt take-up mechanism is also of sub-' stantial importance because of its effect in safe-;

guarding the relatively expensive belt from injury and attendant losses as already explained. The-electrical circuits herein referred to are not illustrated inasmuch as they form no part of the'present invention and are well known reversing motor circuits. Furthermore, it will be understood that the circuits for controlling the motor 13 may also be provided with manual switching means, although .such manual means is not herein shown.

Changes in the described apparatus may be made withoutdeparting. from the spirit of the invention, the scope of which should be determined by reference to the following claims, the

. same being construed as broadly as possible, consistent with the state of the art.

' I claim: a

1. In apparatus of the class described, the combination of an elongated conveyor belt, a drum for supporting the front end portion of the belt, a roller for supporting the rear end portionof the belt, means for adjustably mounting said roller for movement toward or from said drum, a reversable electric motor, means actuated by said motor for efiecting adjustment of said roll selectively in either direction, a vertically adjustably mounted roller adapted to engage said' belt and to move vertically therewith in accordance with changes in the vertical posi- 'tion thereof, electric switch means operable so as to selectively actuate said motor in either direction, and a connection between said switch means and said-belt-following' roller for operating said switch means in accordance with changes in the position of said belt to thereby automatically efiect adjustment, of said roller so as to maintain the belt in predetermined, normal operative position.

operating said switch means in accordance with changes in the position of said'belt to thereby automatically effect adjustment of said roller so as to maintain the belt in predetermined, normal, operative position, said switch means being such as to be initially actuated in one direction upon downward movement of the belt and subsequently in the opposite direction upon restoration of the belt to normalposition, and safety switch means also actuated by said belt-following means for stopping the operation of said motor in the event that said first mentioned switch means should fail to operate. I

3. In apparatus of the class described, the combination of an elongated conveyor belt, a drum for supporting the front end portion of the belt, a roller forsupporting the rear end portion of the belt, means for adjustably mounting said roller for movement toward or from said drum, a reversable electric motor, means actuated by said motor for-effecting adjustment of said roll selectively in either direction, and means controlled by said conveyor belt for controlling the operation of said motor.

" v for supporting the front end portion of the belt,

' tively in either direction, motor control switches,

a roller for supporting the rear end portion of the belt, means for adjustably mounting said roller for movement toward or from said drum, a reversable electric motor, means actuated by said motor for effecting adjustment of said roll selecand means engaged by a portion of said belt and movable thereby for operating said switches to automatically actuate said motor,- whereby the belt is maintained substantially in predetermined normal position.

2. In apparatus of the class described, the corn- .bination of an elongated conveyor belt a drum for supporting the front end portionof the belt. a roller for supporting the rear end portion of the belt, means for adiustably mounting said .roller for movement toward or from said drum,

means selectively operable to eflect adjustment of said roller in either direction, said means comvertical position thereof, electric switch means operable so as to selectively actuatesaid motor in either direction, a connection between said switch means and said belt-following means for 5. In sheet making apparatus, horizontally spaced front and rear rolls, one of'whichis adjustably mounted so as to be movable toward and from the other, a forming band movably supported by said rolls, the band being of such great length that expansion and contraction thereof due to temperature variations substantially changes the length of the belt, power means for adjusting said adiustably mounted roll toward and from the other roll, and means for controlling said power means responsive to vertical shifting ofthe belt beyond predetermined limits, thereby to provide or take up slack in the belt as may be required to' maintain the same, intermediate its supporting rollers within a limited range of vertical shifting.

6. In sheet making apparatus, horizontally spaced front and rear rolls, one of -said rolls being adjustably mounted so as to be movable toward and from the other, a forming-band movably supported by said rolls, said band being of such great length that expansion and contraction thereof due to temperature variations. substantially changes the length of the belt, means for limiting vertical shifting of the. path of travel of thebelt intermediate its supporting rollers because of such changes in itslength, said means comprising power driven means for effecting adjustment of said adjustably mounted roll toward and from the otherroll so as to provideIortake up slack in the belt, and means engaged by.

said belt, movable vertically thereby, and having an operative connection with said power-driven means for actuatingv the same upon vertical shifting of the belt beyond predetermined limits.

EDOUARD M.