US252705A - Mill for grinding and reducing grain - Google Patents

Description

J. STEVENS.

MILL FOR GRINDING AND REDUCING GRAIN, 550.

N0. 252,705. I Patented Ja11.24,1882.

NTTED STATES JOHN STEVENS, OF N PATENT 'EFTQE.

EENA II, WISUONS I N.

SPECIFICATION forming part of Letters Patent No. 252,705, dated January 24, 1882.

Application filed December 16, 1879.

To all whom it may concern Be it known that I, JOHN S'rEvENs,of Neenah, in the county of Winnebago and State of Wisconsin, have inventedcertain new and use ful Improvements in Mills for Grinding and Reducing Grain and other llIaterials, of ,which the following is a specification.

My invention relates particularly to that classof grinding-mills known as roller-mills, in which two or more rolls work against each other and crush or grind the material between them and it consists in an improved dress to be given to the rolls.

In the drawings, Figure 1 is a plan view of a machine embodying my invention, the dress being shown as applied spirally. Fig. 2 is a section on the line 00 00 of Fig. 1. Figs. 3 and 4 represent modified forms of the dress.

A is a frame for the support of the operative parts of the machine. In bearing-blocks (t a upon this frame arejournaled the rolls B The roll Bis driven by means of a sheave or pinion upon its shaft I), connected with any suitable prime motor, and is geared with and drives the roll B in such manner that the two revolve in opposite directionspr toward each other.

The blocksa, in which the roll Bismounted, are secured to the frame by means of bolts or screws which pass through elongated slots in said blocks to permit their horizontal adjustment. These blocks might however, be connected to the frame by means of a tongue and groove to accomplish the same object.

In lugs 1) upon the frame work are set adjusting-screws O, which determine the maximum retreatof one roll from the other. Springs 0, acting in conjunction with these screws, enable such an adjustmentthat the movable roll may yield elastically from the'other to a greater or less distance, and then be positively stopped from further retreating by the screws C. Other screws, D,take into the blocks a upon the opposite side from the first and bear against the blocks a, thereby by their adjustment determining the minimum of distance between the two rolls.

The usual hopper andfeed-roll are intended to be placed above the grinding-rolls, and it will be understood that a suitable meal-chest, conveyer, or other instrumentality will receive the ground or pulverized material beneath and flanks of the contiguous ribs as meeting in an angle, giving a surface of invected outline. In Fig. 3 the. grooves between the ribs are rounded, a cross-section thus presentingthe appearance of a continuing series of ogee curves. In Fi 4 there is a distinct and well-defined space between the flanks or bases of contiguous ribs, each rib thus standing by itself, but not so far removed from the rest as to tail of croperation.

Various other modifications in the shape of the grooves will suggest themselves, the salient feature of my invention being that the ribs shall be rounded-that is to say, made with an outline that presents to the dress of'the opposing roll onlya series of blunt non-cutting crests.

The dress in Figs. 1 and 3 is shown asspiral, being giveuabouta quarter turn (more or less) in the length of the cylinder. In Fig. 4 it is straight, the ribs running longitudinally of the cylinder. When applied spirally it will run in the same direction upon both rolls, in order that, as they revolve, the ribs upon one opposing surface may cross the ribs upon the other. It is not intended, in illustrating the lay of the dress in these figures in connection with special forms which it assumes, to indicate that the particular lay or trend is the best adapted for the special form shown therewith, but only that the dress in all of its modifications may, when laid, assume or range between any of the lines indicated.

The character of the work to be done and the nature of the material operated upon will influence the degree of fineness to be given the dress. Rough work will necessitate a coarser dress than fine work. In some cases, therefore, the dress may be extremely tine, in others measurably coarse.

It may sometimes be found desirable to have the rolls move at the same peripheral speed, and this, though not so generally advantageous, I consider within the principle of my invention.

I do not herein claim specifically anything made the subject of claims in the application filed by me on the 13th day of February, 1878,

of which this present application is a division, and upon which Letters Patent No. 228,001 have been granted to me subsequent to the filing hereot'to wit, upon the 25th day of May, 1880 but 7 I \Vhat I do claim, and desire to secure by Letters Paten is- 1. A dress for the rolls of roller-mills, composed of a series of parallel ribs having blunt non-cutting crests and trending lengthwise of 30 the rol.

-2. In agrimling-mill,tl1.e eombinationot' two rolls driven at ditferent peripheral speeds, and haying a dress composed of a series of parallel ribs trending lengthwise of the roll and formed with blunt non-cutting crests.

JOHN STEVENS. Witnesses:

Jos. G. PARKINSON, S. P. HoLLINesWoR'rn.

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