US550299A - Millstone - Google Patents

Description

(No Model.) l

T. L. STURTEVANT 8: W. H. ELLIS.

' MILLSTONE.

Patnted Nov. 26, 1895.

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UNITED STATES PATENT OFFICE.

THOMAS L. STURTEV ANT, OF FRAMINGHAM, AND IVILIIIAM II. ELLIS, OF BOSTON, MASSACHUSETTS.

MILLHSITONE.

SPECIFICATION forming part of Letters was No. 550,299, dated November 26, 1 895. Application filed September 17,1892 $BIiEt1NO. 446,164. (NomodeL) To all whom it mag concern.-

Be it known that we, THOMAS L. STURTE- VANT, residingat Framingham, in the county of Essex, and WILLIAM H. ELLIS, residing at Boston, in the county of Suffolk, State of Massachusetts, citizens of the United States, have invented certain new and useful Improvements in Millstones, of which the following is a specification.

Our invention relates particularly to composite millstones, such as shown in our Patent No. 483,504, dated September 27, 1892.

We have found in practice that it is highly important that special provision should be made for cutting out the furrows. We have heretofore employed furrow-strips interposed in the skirt, and wefind that, as a rule, the material of which the furrow-strips are made should be softer than the material forming the main body of the stone.

In constructing the improved millstone of our present invention we form the furrowstrips of metal cast in suitably-shaped receptacles between sections of the face of the skirt of the stone, and preferably we build up the skirt of segmental sections that are united and mechanically held together by metal cast in the spaces between the sections and forming the furrow-strips. WVhere the segmental sections are formed of a metal or of a metal having embedded therein lumps or pieces of harder material-such, for instance, as emery-the metal cast between the sections and that of the segmental sections may be such that they will unite or adhere with sufficient tenacity to properly mechanically secure the furrow-strips and sections of the skirt together. We may, however, provide the vertical faces of the segmental sections with recesses or so shape them that the cast metal furrow will mechanically interlock with the segmental sections.

It is immaterial, so far as the scope of our invention is concerned, what material is employed to form the skirt or the bosom of the stone. lVe preferably use emery and zinc to form the skirt and construct it of previouslyformed segmental sections, between which the metal furrow-strips are cast. We may, however, form the skirt in other ways and of other materials, such as blocks of burstone or blocks of other hard stone, and cast the furrow-strips between them. The bosom may beof burstone or any other suitable material, and in' some cases the bosom may be omitted. The cast furrow-strips may be of zinc or of zinc combined with emery or pieces of burstone, or of any suitable material, de pending on the material or combination of materials forming the skirt, since we desire that the furrow-strip shall be of softer material than the skirt.

In the accompanying drawings, illustrating our invention, Figure 1 is a plan view of a millstone embodying our improvements. Fig. 2 is a similar view of a modified form of millstone. Figs. 3, 4, and 5 illustrate different forms of segmental blocks used for constructing the skirt.

In Fig. 1 the stone is shown as composed of a bosom surrounding the eye, which may be of burstone or other: suitable stone, and the skirt is composed of segmental blocks of zinc or spelter and emery or iron and emery, or, in fact, emery may be employed with any suitable binding material, zinc or spelter being preferred.

The segments to form the skirt may be made separately and may be formed with recessed sides-for instance, with concave sidesas shown in Fig. 3, with grooves a, as shown in Fig. 4, or with perforations b, as shown in Fig.- 5. ments are placed within a ring A and around a burstone B, suitable spaces being left to receive the metal that forms the furrow-strips (J. If zinc or like material is employed for forming the furrow-strips, it is poured in between the segments D, and when it cools and hardens will hold the segments at proper distances apart and will be securely held in place by reason of the curved, grooved, or perforated formation of the segments, as above eX- plained,'and as shown in Figs. 3, 4, and 5. Fig. 2 shows substantially the same formation,except that there is no separately-formed bosom surrounding the eye, and a ring A is employed to bound the inner ends of the segments and furrow-strips.

It is not essential, so far as parts of our invention are concerned, that the skirt of the stone should be made in sections. The stone In constructing the stone these seg-' may be constructed in the manner described in Letters Patent granted to Thomas L. Sturtevant September 27, 1892-that is to say, the furrow-strips may be cast in receptacles in a continuous skirt.

One specific way of forming the stone which may be mentioned is the following: The segments or skirt-sections, formed of zinc and small blocks of emery, are placed in position 011 a plate P, Fig. 1. An outside temporary former or binding-band A is slipped in place around them, and the bur bosom B is put in position, or when the bur bosom is not used an iron band A, as shownin Fig. 2, takes its place. Spaces for the furrow-strips are left between the segments, and. in these spaces we place broken pieces of burstone and then pour in molten zinc, which, on cooling, binds the stone blocks firmly together. \Vhen the zinc is cool, we remove the temporary former, bind and shrink a permanent binding-band about the stone, which may then be turned over, and the side which rested on the plate P before will have a sufficiently smooth face for work.

lVe claim as our invention 1. A mill stone having a skirt composed of previously-formed sections of grinding material, and metal cast between the sections entering recesses in the sides thereof, and forming the furrow strips, substantially as set forth.

2. A mill stone having a skirt formed of sections composed of metal with pieces or blocks of harder material, such as emery, embedded therein, and metal cast between the sections entering recesses in the sides thereof and forming furrow strips, substantially as set forth.

3. A mill stone having a skirt formed of segmental sections composed of cast metal with pieces or blocks of harder material embedded therein, and furrow strips of metal softer than the skirt sections cast between said sections and entering recesses in the sides thereof, substantially as set forth.

4. A mill stone comprising a skirt made up of sections having recesses on their adjacent faces and metal furrow strips cast between them and filling the recesses in them, substantially as set forth. i.

5. The millstone herein described, comprising an eye of burstone, a skirt composed of segmental sections of blocks of emery and zinc, and furrow strips composed of zinc and blocks of burstone.

6. The millstone herein described comprising a skirt composed of segmental sections, of blocks of emery and zinc, and furrow strips composed of zinc and blocks of burstone.

In testimony whereof We have hereunto subscribed our names.

THOMAS L. S'lUR'lEVAN'l. WILLIAM H. ELLIS.

\Vitnesses:

EDWARD H. MASON, MARY SHEEHAN.

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