Year: 1898

page_text: We, KNUT ELOF LJUNGMAN, of Odengatan, 8, Stockholm, Sweden, Mechanical
Engineer, and OTTO UNDEN, of Gossater, Sweden, Mechanical Engineer, do hereby
declare the nature of this invention to be as follows.-
This invention relates to grinding-tools for the grinding of stone, metal and other
materials. The invention consists, briefly, in that the tool, instead of being formed
as a single piece of grinding-mass as hitherto customary, for example emery-wheels,
consists of a suitable holder, in which the grinding pait or parts are mechanically
held. The holder as well as the gunding part may be of any suitable shape and
consist of one or more pieces. The invention may of course be applied either to
rotating grinding-tools or to grinding-tools used in any other way
In the accompanying diawing is shown three modifications of a grinding-tool
constructed according to this invention.
The
Fig 1 shows a side-elevation, Fig. 2 a plau-view and Fig. 3 a cross-section of
a part of the holder of a grinding-wheel, at the circumference of which cross-shaped
giinding-pieces c are inserted Figs 4, 5 and 6 show the said grinding-piece con
an enlarged scale in side-views at right angles to each other and in plau-view
The said grinding-pieces c have here the form of a cross and are fitted into grooves
or the like of a corresponding form between two rings a¹, a³, fastened to a circular
disk b, which is keyed or in any other suitable manner attached to a shaft
grinding-pieces e are firmly held between the rings a', a' by giving the projections c³
of the grinding piece a dove-tailed shape, said projections being inserted between
the rings a, a in cavities which are widened inwards to suit the projections.
Figs 7 to 12 show in the like manner a part of a grinding-wheel, in which
the holder rings a³, a* in cross section look like hooks, so as to grip about a pro-
jection of the grinding-pieces c', which are placed close together, thus forming
a continuous ing
Figs. 12-14 show in the same way as in Figs 1-3 a part of another grinding-
wheel. A ring a³, which may be cast, 18 here fixed between the edges of two circular
discs 1, 2, said unga being provided with transverse dove-tailed grooves or
slots, in which the correspondingly shaped grinding-pieces are placed
The construction shown in Figs 1-6 is especially adapted for tools for working
very hard and tough objects That of Figs 7-11 is more adapted for the grinding
of loose material and that of Fig 12-14 for gunding broad surfaces
The manner in which the grinding-pieces are fastened in the holder may of
course be vaned in several different ways For instance pieces of the grinding-ma-s
may be inserted after being formed in a shape ready for use (as shown in the diaw-
ing) or a plastic grinding-mass may be cast into the corresponding cavities of the
holder, or the latter can be cast around the grinding-pieces or the gunding-ring.

page_text: If gunding-pieces are inserted, the same can be fastened between the holding
sui faces by means of stone-cement or its equivalent
As already stated, the said constructions only serve as examples and the invention
consists chiefly therein that a grinding-tool, instead of being formed entirely of
grinding-mass, as luther to customary, consists of a metallic holder and grinding
parts held in the surface of said holder in any suitable way
We, KNUT ELOF LJUNGMAN, of Odengatan, 8, Stockholm, Sweden, Mechanical
Engineer, and OT10 UNDEN, of Gossater, Sweden, Mechanical Engineer, do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment..
The present invention relates to a ginding-tool for working stone and like
materials, principally characterized by a gunding-composition formed into dies of
suitable shape and embedded in such a manner in a metal holder, composed of one
01 more rings or made in some other suitable manner, that the said holder wears
oft together with the dies which latter consequently project only so far as the wear
of the metal exceeds that of the dies, thus obtaining the best possible support of
the gunding pieces
The invention 18 illustrated in the accompanying drawing as applied to a 1otating
web or disc Fig 1, 2, and 3 respectively show in an elevation, plan-view, and
a sectional view two rings b secured to the circulai web a and provided at their
cucumference with grooves or cavities 61 intended for holding the teeth 6+ made of
a plastic mass and which teeth either after hardening may be clamped in position
between the rings or may be forced in place while the composition is still soft
In Figs. 45 and ti 18 shown in a corresponding manner a wider ring supported
by two or more circular discs and provided simply with dove-tailed grooves for
the teeth b³
The construction shown in Figs. 1--3 is intended for the sawing or splitting of
blocks of stone, while that shown in Figs 4-6 is designed for surface-milling
of large surfaces It is evident from both examples that the weaung of the holder
is necessary for the operation of the tool
The ginding-pieces may of course be inserted in the holder in various manners,
thus, for instance, ready shaped pieces of the grinding-material may be inserted
(as is assumed to be the case in the constructions shown in the diawing), or a plastic
grinding-composition may before hardening be cast into the corresponding cavities
of the holder or the holder itself may be cast around the grinding-pieces or the
grinding-ring If ready-shaped grinding-pieces are inserted, these may be secured
between the holding-pieces by some stone-cement.
Having now particularly described and ascertained the nature of this said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is -
A grinding-tool for working stone and like materials, characterized by the grind-
ing-material being formed into dies of suitable shape and so embedded in a metal

page_text: holder that the holder wears off together with the grinding bodies, in order that
the grinding bodies may obtain such good support from the metal that they do not
burst asunder substantially as set forth.
Dated the 7th dor of March 1900
W. P THOMPSON & Co,
Of London, Liverpool, Manchester and Birmingham.