A NEW OR IMPROVED MECHANICAL HOLDER OR GRIPPER
Year: 1884

page_text: "
I, JAMES HARROWER, of Preston Crescent, Inverkeithing, in the County of Fife,
North Britain, Engineer do hereby declare the nature of the said invention for
A NEW OR IMPROVED MECHANICAL HOLDER OR GRIPPER" to be as follows :—
This Invention, which relates to a new or improved mechanical holder or gripper,
is applicable for holding solid or hollow objects in all classes of Machines in which
concentric or eccentric rotating motion takes place. It may be applied to Turning
Lathes, Screwing Machines, Drilling or Boring Machines, and other Machines of
analogous types-It may also be used as a centre or carrier for holding hollow
bodies such as pipes or Cylinders in a Lathe or other such Machine.
The holder consists of a circular body-piece with a hole in its centre for attaching
it to the rotating Mandril of the Machine in which it is to be used.-Upon this
body-piece there is carried a circular plate on whose face there is formed a volute
scroll, and on the back face of each jaw or jammer there is formed a rack whose
teeth correspond to the recesses and projections in the scroll-plate, so that by
turning the scroll-plate round in either a backwards or forwards direction the jaws
or jammers are moved inwards or outwards so as to hold the body either interiorly
or exteriorly. For the purpose of tightening the jaws or jammers a jam nut is
provided at the back of the holder which presses all the parts tightly together.-
For the purpose of enabling the apparatus to be used as a centre for hollow objects
it is provided with three, four, or more snugs with set screws which tighten the
Heveral parts together when the jam nut is removed as is the case when the
apparatus is used as a centre.

page_text: I, JAMES HARROWER, of Preston Crescent, Inverkeithing, in the County of Fife,
North Britain, Engineer do hereby declare the nature of my said invention for
A NEW OR IMPROVED MECHANICAL HOLDER OR GRIPPER and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:―
My Invention, which relates to a new or improved mechanical holder or gripper,
is applicable for holding solid or hollow objects in all classes of machines in which
concentric or eccentric rotating motion takes place. It may be applied to turning
lathes, screwing machines, Drilling or Boring Machines, and other machines of
analogous types. It may also be used as a centre or carrier for holding hollow
bodies such as pipes or cylinders in a lathe or other such Machine.
The holder consists of a circular body-piece with a hole in its centre for attaching
it to the rotating mandril of the machine in which it is to be used. Upon this
body-piece there is carried a circular plate on whose face there is formed a volute
scroll, and on the back face of each jaw or jammer there is formed a rack whose
teeth correspond to the recesses and projections in the scroll-plate, so that by
turning the scroll-plate round in either a backwards or forwards direction, the jaws
or jammers are moved inwards or outwards so as to hold the body either interiorly
or exteriorly. For the purpose of tightening the jaws or jammers, a jam nut is
provided at the back of the holder, which nut presses all the parts tightly together.
For the purpose of enabling the apparatus to be used as a centre for hollow objects,
it is provided with three, four or more snugs with set screws which tighten the
several parts together when the jam nut is removed as is the case when the
apparatus is used as a centre.
In order that my said Invention may be most fully understood and readily
carried into effect, I will now proceed to describe the drawings hereunto annexed.
Figures 1 and 2 are respectively a front and a back elevation of a mechanical
holder or gripper constructed according to and constituting my present Invention.
Figure 3, is a plan and Figure 4 is a horizontal section of the same.
Figure 5, is a back elevation of the same with the scroll plate removed.
Figure 6, is a face view of the scroll-plate.
Figures 7 to 14 (inclusive) are views of the tightening jaws of the same.
The holder or gripper as shewn upon the annexed drawings consists of the body
piece A, through which a hole is formed and screwed for attaching it to the rotating
mandril of the machine in which it is to be used. Upon and around the tubular
part b, of the body piece A, the circular plate c, is carried, and is capable of being
rotated thereon. Upon the face of this plate c, there is formed the volute scroll d
as shewn more particularly at Figure 6. The recesses and projections of the volute
scroll correspond to, and engage with the teeth e, with which teeth the said scroll is
maintained in gear by means of the screwed jam-nut f, and collar g, which also
provide for the tightening or locking of the parts together. The teeth e, are formed
on the back of each of the pieces h, which constitute a part of the gripping jaws;
or they may be constituted of rollers pivoted upon pins secured to the said pieces h
These pieces h, one of which is shewn detached, in back, side and front elevations

page_text: and in plan respectively at Figures 7, 8, 9 and 10, work in guides formed radially
in the body-piece A and are each constructed with forked ends formed at right-
angles to the direction of their length. Between the arms i, of these forked ends,
the screws j, are capable of being rotated, while they are secured against longi-
tudinal motion therein, by means of the collars k, formed on the shafts of the said
screws. The screws j, may, by means of a box-spanner, key or its equivalent, be
screwed farther into or out from the jaws I, which are guided radially in the body-
piece A, and consequently any article may be held concentrically or eccentrically
within the gripper. One of these jaws l, with its connected screw j, is shewn
detached in back, side and front elevations and in plan respectively at Figures 11,
12, 13 and 14. The circular plate c, is secured within the body-piece A, by means
of the set-screws m, which are carried in the plates n, and which may be locked in
any required position therein by means of the lock-nuts o. At the back of the
plate c, there is provided the toothed wheel p, and gearing with this, is the pinion q,
which is carried upon the stud 2, held in the plate 8, (Figure 2) and which is formed
with the square portion t, at its back. The tangent screw u, may also be geared
with the teeth of the wheel p, by rotating the screw v, so as to advance the tangent
screw u, inwards until it gears with the said teeth p. The tangent screw u, is
secured to the shaft w, which is squared at its outer end and is carried in the two
arms, of the forked block y. The block y, and the shaft w, are capable of sliding
in the fixed guide plate z, the screw v, being secured against longitudinal motion in
the block y, by means of the collar a¹, fixed thereon.
The opening or closing of the jaws l, may be effected when the tangent screw u,
is in gear with the teeth of the wheel p, by rotating the said tangent screw in the
required direction by means of a crank handle or other key applied to the squared
end of the shaft w, or the said adjustment may be effected at a quicker rate by the
toothed pinion q, when the tangent screw is out of gear with the wheel p. For this
purpose a crank handle or its equivalent is applied to the squared portion t, of the
pinion q, and if desired, the plate c, may be secured in any position so arrived at,
by gearing the tangent screw u, with the teeth of the wheel p. The collar g, is
capable of slight longitudinal motion upon the tubular part b, for effecting the
tightening of the plate c, but is prevented from moving rotatively thereon by means
of the key or feather 61, Figures 2 and 4. The plate c, when forced forward by the
jam nut f, is pressed upon the raised block c', which with the packing pieces d²,
(Figures 4 and 5) support the toothed portions e, of the gripping jaws 7, at their
longitudinal sides.
It is to be observed that the jaws l, are of such construction as admit of portions
of mechanism being gripped thereby either internally or externally, and that there
may be employed two, three or more such jaws, each of which may be formed with
snugs and provided with a screwed bolt or its equivalent for still further securing
internally or externally, the portions of mechanism to be thereby held. I desire it
to be understood that the jaws proper may be operated directly from the scroll
plate, that is to say, by means of teeth or their equivalents formed at the back of
the said jaws, engaging with the volute scroll, and that this volute scroll may
be rotated by means of a spanner, key or its equivalent; this latter form of
construction being specially applicable for holding drills, borers or other like tools
or apparatus in their chucks or drivers. I also desire it to be understood that
I may arrange the gripping jaws between two scroll plates, two sets of teeth or
their equivalents being formed on the said jaws for this purpose; or, the two scroll
plates thus employed, may each operate jaws proper to itself, that is to say
independently of one another.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim is
First. The improved mechanical holder or gripper in which the jaws 7, are opened
and closed by means of the volute scroll rotated by the tonment ID
AL

page_text: toothed pinion q, or their equivalent and with or without means for adjusting
and tightening either concentrically or eccentrically consisting of the screw j, all
operating in combination substantially as and for the purposes herein before set
forth with reference to the annexed drawings or the mechanical equivalents of all
or any of the parts thereof.
Second. The tightening nut f, and the set screws m, for tightening the several
parts of the holder together after their respective positions have been severally
adjusted substantially as herein before set forth with reference to the annexed
drawings.