USRE625E - Improvement in grinding mills - Google Patents

Description

PATENT OFFICE.

EDWARD HARRISON, OF NEW HAVEN, CONNECTICUT.

IMPROVEMENT IN GRINDING MILLS.

Specification forming part of Letters Patent No. 11,040, dated June 6, 1854; Reissue No. 695, dated K November 1G. 1858. f l

To all ywhom it may concern:

the city and county of New Haveminthe State of Connecticut, have invented certain new and useful Improvements in 'Mills for Grinding Grain; and l do hereby declare that the following speciiication, taken in connection With the drawiu gs, is a full, clear, andegract description thereof.

Figure l is a vertical section through the center of one of my improved grinding-mills. Fig. 2 is a bottom View of the mill. Eig. 3 isa bottom View ofthe shoe and aportion of the hopper detached, and Fig. 4 is a view of the top of the shaft.

The same letters indicate like parts in all the figures. y

E E, Fig. l, represent the upper or stationary stone, and F F the lower or runner stone. The upper stone, E E, is cemented orrmly secured by bolts within the upper casing, A, and the ruimer F F is by the means hereinafter more particularly described secured to the metallic hub and back W D, which is keyed or otherwise made fast to the spindle C.

Motion having been communicated to the spindle, the runner-stone is rotated in a plane parallel with the face 'of the stationary stne, and freely Within the casing B, which incloses it. vThe grain is supplied to the milliu the,

ordinaryr way by means-of a shoe fed froma hopper, and, passing through theveye of the stationary e,falls upon therunner-stone,wlien, from the high speed at which this discription of mill is capable of being run, it seeksa point as far as possible from the center of the runner, and is thus distributed between the grindin g-surfaeesI of the two stones and converted into flour orf'ineal.

Aside from the features which, in point of construction, distinguish my mill from and render it more compact, efficient,r and economical than any other heretofore known,vmy improvementparticularly relates to themethod by which the runner-stone is. secured to the spindle so as to render the stone capable of receivingrthe highest safe velocity withoutthe -dai/iger of 'its Wearing loose 011 the spindle,l thereby increasing greatly the productive capacity of the mill, While at the same time' the lnethod of attachment employed admits of the ruuerlstone being used until it hasbecome worn so thin as to'be worthless, when it can be readily removed and a fresh stone easily sub-y stituted. Y

The principal difliculty which has beenexperienced heretofore in that class of mills where the runner-stone was attached to a shaft or spindle and revolved by means of it has been fo permanently secure the stone from Wearing oose. through the runner by any ofthe modes of attachment formerly in use the resistance due to the grinding of the grain was necessarily encountered by the devices which connected the runner with the spindle. Where this device consisted of a metallic hub and a back l the same cause, while an attempt to secure a runner-stone to the spindle by keying it on as a grindstone is keyed to its shaft, haslproved entirely ineffectual in mills of any size, and iu any case where this means is employed the mill having it must soon become from usea most inecientjand inferior machine. To obviate this diiculty as far as possible, by distributing the resistance arising from the use to which the mill is put, and causing it to be expended upon the metallic back, and hub rather than upon any particular point or points of connection between the runner and back or runner and spindle, is the object of my inven- 4 tion. To accomplish thisl I have, as shown in the drawings, extended the metallic back lto Athe outer edge of the stone, andcloselyunit'ed the peripheries of both by means of a metallic ring, a @which ring performs not only the function of the ordinary band in enabling the stone to resist the effect of centrifugal force,

Lbut alsonforms with the back a metallic cup,

within which -the runner is placed, fand means of-which itis kept in position.

The great advantagewhich is the result of this method of construction is apparent when it is observed that there is no diiiculty in keying the metallic hub to the spindle While the runner isheld in its place by the grasp of the external ring upon the stone and the back, ex-

In all cases where the shaft passed erted throughout the whole periph eries of both which grasp for retaining the stone in place is` at points more remote from the center of the spindle than the farthestpoint of resistance arising from the use of the mill in grinding grain. So long, therefore, as the friction of the metallic band upon the stone andfmetallic back, aided by its advantage of location justnamed, is superior to the friction caused by Agrinding the grain, the runnervstone will .remain immovable.

A necessary advantage which results from the mode of attachment described is the facilil ty` with which the faces of the two stones can be made true by grinding them together, the glazed points, which are the result of this operation, indicating where the pick is required. Besides, too, the runnerstone bythis method can be adjusted and made to revolve so accurately with reference to the stationary stone that the vfaces of the two, when the former is at its speed, sha-ll be so near together as to produce the finest flour or meal. Yet when the feed is shut oli' the stones will not, as is the Y case in al1 other varieties of mills after a short use, come in contact-and be dull'ed. I am aware that in the construction of millstones intended to be operated by a. bail and, V

driver a metallic back and iiange has been made in one piece, the Hangeor rim in such case serving the purpose of the ordinary hoop, and instead of a rim of iron vcast with the back a wrought-iron rim has been used to bind together a back made in sections and I am also aware that a metallic hub and aback-plate of less diameter than the runner have been used in mill-stones intended to be driven bya spindle. Therefore I do not claim any of these separate1y5-but What I do claim as my invention, and desire tosecure by Letters Paten t, is-

The improved method described of securing the runnerstone on. the driving spindle in a grinding-mill by means of a metallic band orits equivalent, embracingrthe periphery of the stone, by combining said band with a hub .and a back-plate of at least as great diameter as the runner, and rigidly attached to the spindle, such combination operating to secure 'the stone tirmly in its place, in the manner and onl thev principle substantially as specified. A EDWARD HARRISON.

'Witnessesn A. B. JoooKs, I. G. Jnoooxs.

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