US2656121A - Automatic material feed control for cereal comminuting apparatus - Google Patents

Description

Oct. 20, 1953 F. TANNER 2,656,121

I I AUTOMATIC MATER FEED CONTROL FOR v CEREAL COMMI ING APPARATUS Filed Dec. 2'7, 1949 2 Sheets-Sheet l Patented Oct. 20, 1953 AUTOMATIC MATERIAL FEED CONTROL FOR CEREAL COMMINUT-ING APPARATUS Fritz Tanner, Sankt Gallen, Switzerland, assignor to Gebriider Biihlcr, Uzwil, Switzerland Application December 27, 1949, Serial No. 135,238 In Switzerland April 14, 1949 1 Claim.

In all prior-art arrangements for automatically regulating the material fed to the grinding rolls by means of a control device disposed in the mill hopperand of a fluid-operated servomotor controlled thereby, which act either on the feed segment or the number of revolutions of the feed rolls, the servomotor is mounted on the mill outside. Such disposition requires a rather long rigging between the control device in said. hopper and the servomotor precontrol means on one hand, and between the servomotor and the feed segment in the said hopper on the other hand. Due to such disposition, therefore, frictional losses and inaccuracies arise in transmission, perhaps also a clogging or choking through material or foreign bodies being retained in said rigging, and also higher costs of manufacture. Finally it becomes rather difiicult to subsequently incorporate such automatic material feed control means in existing mill units of older construction in that, as a rule, substantial structural changes have to be made in the hopper and in the rigging to the feed segment, and the mill unit casing has to be drilled for the passage of rigging shafts. By rigging is understood a lever connection associating the controller and the servomotor.

All the said deficiencies shall be avoided by means of my present invention in that the hopper control means and servomotor are combined,

without any rigging, to a unit which is mounted directly in the hopper.

The improvement consists in the combination of a controller, a servomotor, and means controlling the servomotor directly by the controller, without any such rigging, the controller and servomotor forming a structuralunit disposed directly in the hopper, above the cereal feed valves, the servomotor operating directly upon said valves on the action of said controller. And a preferred form is to have the servomotor piston co-axial with the stem of the controller, so that the direction of movement of the servomotor axis coincides with that of the controller stem.

The invention will be further described, an embodiment shown in the drawings, and the invention will be finally pointed out in the claim.

A known non-automatic material feed control means and one form of my present invention are the present invention. In a twin mill unit embodying this invention,the left hand side is the same as the right hand, except in reverse. The

left hand side of Fig. 1, is shown to indicate the known, structure for the purpose of having the right hand side point out the novelty of the present invention over the old; and

Fig.2 shows a vertical section through the hopper feed control means of Fig. 1, but in a much larger scale.

Similar characters of reference indicate correspending parts throughout the various views.

, ,In Fig. l, the grindingrolls are designated by l, and the feed rolls by 2. In the left side of Fig. 1, the segmental feed gate? is pivoted at 4 and rigidly connected to an arm 5 which co-acts with an arm I. The latter passes through an aperture 1 inthe hopper partition 8 and is secured to a pin E which controls the width In over the entire length of the mill unit and biases the feed gate ,3 through the arms I and 5. The gate 3 is kept in balance against the pressure of the material through its own weight, if required a spring means may be used for equalizing the said pressure. The more material is moving down the hopper, the

- higher the gate 6 is loaded and the more the gate he opened. The arms I and 5 form a linkage be- 1 tween the gate 6 andthe feed gate 3. In the improved form, said arms I and 5 form a linkage between the arms 6 and the feed gate 3.

In the right side of Fig. 1, the segmental feed gate 3, the arms5 and 1, and the partition 8 are similarly constructed asin the left side of j Fig.1. In place of the gate 6 forming the con- 1 troller in the left side of Fig. l, a narrow arm 5 is provided, which may consist of a fiat.

arm 6' coacts with a roller H of a servomotor 12 which issecured, adjustably in elevation, to

The

the center wall of the mill unit casing by means of a holder 13. The servomotor I2 is operated by I means of compressed air supplied through a pipe shown in the accompanying'drawings, in which- I4 extending from the outside of the hopper. A

controller 15 is mounted on the servomotor I 2.

The feed rolls 2 have one roll higher than the otherand the upper one is spaced from the lower end of the hopper wall In this space a segmental feed gate '3 moves to open the space or to close it, depending on the position of the roller ll of the extending end of the piston of said servomotor l2. The position of the feed gate 3 controls the amount of material over the feed rolls 2 flowing to the grinding rollers I.

As shown in Fig. 2, a piston I! with a sealing sleeve I8 is disposed in the cylinder it of servomotor [2. The piston I1 is loaded by a spring 19 which tends to push the piston upwardly against a plug 20. The roller I I coacting with arm 6 is mounted on the foot end of piston I1. A guide bush 2! is screwed into the head of piston I! and has an axial bore 22 which co-acts with a control pin 23 of controller l5. When the pin 23 is in the position shown in Fig. 2, in which the controller I5 is not loaded, the compressed air entering through pipe 14 into cylinder i6 escapes to the outside through the bore 22 and a plurality of holes 2l-25 in piston H, I case remains in its topmost position, and the gate 3 is closed. 7

When, however, the controller I5 is loaded, the pin 23 is depressed and closes bore 22. The compressed air entering through pipe l i depresses piston IT, and gate 3 is swung open by means of roller H and arms 6', l. and 5. I

At the lower end of piston I! a set collar 2'3 and bellows 28 are provided, which latter form a sealing means against the ingress of material into servomotor iii. For the same purpose, bellows 29 are provided between servomotor l2 and controller l5.

The axis of the servomotor l2 which is coincident with the axis of its piston I! is vertically aligned with the axis of the controller shaft or pin 35.

The controller l5 comprises a vertical tubular stem as which on top is closed through a plug 30, and sheet-iron gable members 3|. To the head of stem 30 a bolt 32 is secured which has a ball-shaped foot 33 and is retained in a bush 3t. The latter is secured to a coupling pin 35 which thus is articulated to the bolt 32 and connected to stem 36. The coupling pin 35 on its foot carries a bush 3% which retains the ball-shaped head 3? of the control pin 23. A piece of gas pipe 38 threaded over substantially its entire length, is screwed in the plug of servomotor cylinder Ill and carries a nut 39 which serves for adjusting the force of a spring 4i When feeding a specifically lighter material, nut 39 is moved down wardly, thereby reducing the spring force. When feeding, a heavier material, nut 39 is moved upwardly, thereby increasing the spring force.

When the controller i5 is not loaded by material in the hopper, piston 16 and guide bush due to the force or pressure of spring I9 is in the topmost position in which the bush 2! abuts against plug 28. The compressed air entering through the pipe M then escapes to the outside through the bores 22 and 2426 in piston [1.

When, however, the controller I5 i weighted through the material, the stem is depressed through the gable members 3! against the action of spring it, the control pin 23 being taken along and covering the bore 22. The compressed air entering the servomotor through pipe M, then depresses piston ll, thereby opening the segmental swing gate 3 through the roller II and the arms 8, l and 5. The gate 3 is still further opened on increasing the feed of material, and closed on decreasing the same. In normal operation, the control pin 23 always substantially closes the bore 22 entirely, until the piston l1 abuts on tops against the plug 20 and the compressed air escape to the atmosphere.

The latter in such The automatic control means described may be mounted in all mill units practically without any structural change of the existing material feed controller means. It also permits to efiect the throwing in and out of gear of the grinding rolls and the feed rolls, without requiring a second pipe line to the interior of the mill unit besides the line H. In such latter case, the power cylinder effecting the said movement is mounted directly to the manually-operated control lever of the mill unit. My present invention also affords advantages when regulating the material feed through adjusting the number of revolutions of the feed rollers, since here also the rigging from the controller to the precontrol is eliminated. The rigging from the servomotor to the revolution governer is not so easily disturbed through the material in the hopper, since substantial forces are available for the servomotor.

What I claim as new and desire to secure by Letters Patent, is:

In an automatic feed control means 'for cereal comminuting apparatus having grinding rollers, feed rolls, one higher than the other, and both above the grinding rollers, a hopper having walls above said feed rolls, the lower end of a hopper wall being spaced from said higher feed roll. a segmental feed gate between said higher roll and said lower end of said hopper for controlling the amount of material to said feed rolls, the combination of an arm transverse to the hopper havin one end hinged to a wall of the hopper, linkbetween said arm and said feed gate, to open said feed gate when said arm is in a downward position and close said feed gate when the arm is in its upper position, a servomotor having a piston in hopper, one end of the piston extending out of said servomotor, a fluid supply pipe extending from said servomotor within to the outside of said hopper, a bracket secured to the innor wall of said hopper for supporting said servomotor within said hopper in the path of the cereal feed flow, said servomotor having an axis vertically aligned with its said piston, and a controller within said hopper above said servomotor having laterally extending vanes for supporting cerealand having a vertical shaft for said vanes, said shaft extending from said controller into said servomotor for regulating the fluid supply to said servomotor and the consequent position of its said piston on said arm, said controller shaft having an axis vertically aligned with said axis of said servomotor, forming a structural unit. whereby when cereal in the said hopper weights said controller vanes over a balanced amount, said shaft descends into said servomotor to compel said supply fluid to move the servomotor piston and said arm downwardly and by said linkage to open said feed gate, and when the cereal on said vanes is less than said weighted amount, the servomotor supply fluid is shut off and said gate closes against any feeding of said material to said feed rolls and to said grinding rollers.

FRITZ TANNER.

Name Date Moog Sept. 9, 1930 Number

Images