Lathe Drivers or Carriers.
Year: 1889

page_text: Date of Application, 1st July, 1889
Complete Specification Left, 24th Sept., 1889-Accepted, 26th Oct.,
1889
PROVISIONAL SPECIFICATION.
Lathe Drivers or Carriers.
I, CHARLES WELLS SHARTLE, of Middletown, Butler County, State of Ohio,
United States of America, manufacturer, do hereby declare the nature of this invention
to be as follows:-
This invention pertains to drivers or dogs to be employed in lathe work and similar
work where round articles are to be grasped and rotated. The object of the invention
is to produce a lathe driver or dog which may be applied to the work by the mere
manipulation of thumb-screws and which will have the property of not having its
grasp upon the work limited by the power with which said thumb-screws have been
screwed down. The object is accomplished by causing the work to be impinged upon
by a pair of converging thumb-screws and by a serated pivot-block disposed opposite
the thumb-screws and adapted to take a bite upon the piece with a pressure increasing
as the necessity requires, the face of such pivot-block being serated so as to take a firmer
hold and having such facial conformation that it is capable of forcibly biting the piece
regardless of the direction of rotation of the driver. Where the driver is to be
employed with a tapered piece of work then a pivot-block may be used which has
its face correspondingly tapered whereby a fair bearing of the block upon the piece of
work is secured.
The driver may be provided with two tails, oppositely disposed, one tail projecting
radially, while the other tail projects radially and is then turned to project parallel with
the axis of the driver.
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Lathe Drivers or Carriers.
I, CHARLES WELLS SHARTLE, of Middletown, Butler County, State of Ohio,
United States of America, Manufacturer, do hereby declare the nature of this
invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention pertains to drivers to be employed. in lathe work and similar work
where round articles are to be grasped and rotated. My present improvements will
be readily understood from the following description, taken in connection with the
accompanying drawing, in which :-
Fig. 1 is a perspective view of a lathe driver embodying my improvements.
Fig. 2 a face view of the same.
Fig. 3 a face view of that portion of the driver at which the jaw is pivotted, the
jaw and its cover being removed.
Fig. 4 a perspective view of the pivot jaw in reversed position to expose the
trunnion upon what would be the lower surface of the jaw viewed under the conditions
upon which Figs. 1, 2 and 3 are made.
Fig. 5 a view of the jaw cover removed.
Fig. 6 a vertical transverse section of the stock, in the plane of the axis of the jaw
pivot; and
Fig. 7 a vertical longitudinal section of the driver, in the plane of the pivot of the
jaw, this view showing the parts reversed in position, that is to say, the cover K is
below as if the driver shown in Fig. 1 were turned over so that the tail C, bent
downwardly. Figs. 3, 4, 5, 6, and 7 are upon an enlarged scale.

page_text: In the drawing A indicates the usual stock provided with an eye to receive the work
which the driver is to drive.
B, a tail projecting radially therefrom to serve, in the lathe, in rotating the driver
through the medium of an ordinary driving stud projecting from the face-plate of the
lathe.
C, a tail projecting radially from the stock opposite to the tail B, and turned at
right angles to the general plane of the stock, this tail being adapted to engage one of
the usual slots in the face plate of a lathe.
D, a pair of convergent set-screws, screwed through the stock, one upon each side
of the tail C. these set-screws projecting into the eye of the driver, the axes of the
two screws intersecting at a point eccentric to the eye of the driver, such point
being located between the centre of the eye and that wall of the eye which is toward
tail B.
E, that portion of the stock formed by the juncture of the tail B with the metal
surrounding the eye.
F, a recess in that wall of the eye which is toward the tail B, this recess being
open to the eye of the driver, and also open at one face of the driver.
G, a pivot hole through the floor of this recess.
H, that wall of the recess which is toward the tail B, this wall being concentric with
the pivot hole G.
J, a cover-recess in the face of the stock, over the recess F, this cover-recess being
dovetailed at its side walls, and open towards the eye of the driver so that the plate
can be slid into the cover-recess, and form a roof for the recess F.
eye
L, a pivot-block pivotted in the recess F and presenting a serrated face to the of
the driver facing toward the set-screws D. the heel of this block being shaped to fit
the wall of the recess F, so as to take a bearing of oscillation therein; and
M, a trunnion integrally formed with and projecting from one face of this jaw,
concentric with its heel surface, and adapted to fit within the pivot hole G.
This driver is a self-gripping affair, and the set-screws D are only required to serve
in adjusting the size of the dog, so to speak. Therefore these set-screws may be
thumb screws.
Assume that the set-screws are entirely absent, and that a cylindrical
piece of iron, as large as can be put into the driver, be inserted in the eye of the
driver. If an attempt be made to rotate this piece of iron, that attempt will cause a
partial rotation of the jaw upon its pivot, and will, in an obvious manner, cause that
jaw to exert a biting grip upon the piece and prevent its further rotation in the eye of
the driver. This occurs with either direction of rotary motion. It is further obvious
that if the piece of work in hand be a trifle smaller than that just assumed, the
partial rotation required of the pivotted jaw before its forcible grip would take place
might be greater than the dimensions of the recess F would permit, in which case the
jaw would not grip the piece. Hence the necessity of, the set screws for adjusting the
practical size of the eye to properly conform to the size of work in hand. The object
of having the set-screws diverge to a point eccentric to the eye of the driver is to
enable these screws to be moved further inwardly when very small work is in hand,
without the points of the set-screws coming in contact with each other.
The working strains upon the pivot block are met by the heel of the block bearing
in the wall H of the block recess, the trunnion being free from strains and serving as
a mere expedient to keep the block from falling out of the recess when not under
strain. The cover plate is held in the recess J by mere friction, and can be readily
removed. The office of this cover plate is to prevent the trunnion from leaving the
pivot hole.
While this jaw grips with enormous force, and while no wrench is needed in applying
the driver to the work, it is still found in practice that the driver does not mar finished
work to any such extent as is the case with ordinary drivers engaging the work by
powerful set-screws. It is desirable that the serrated face of the pivotted jaw engage
fairly lengthwise along the piece of work in hand. Consequently, when cylindrical
work is to be driven, the serrated face of the jaw should be parallel to the axis of the
jaw. But such a jaw as this would bite at one end of the serrations only, when

page_text: applied to the tapering work. The driver would thus have a tendency to work off the
same as is the case with ordinary set-screw drivers. In my improvel driver, however,
this trouble may be avoided by using a pivotted jaw whose serrated face is at an angle
to the axis of the jaw so that the face will have a fair bearing on the taper work in
hand. The driver, thus provided, will take an unyielding grip on finished tapered
work without seriously marring the work, and will not work off the ordinary
tapers.
The driver when constructed with two tails, as shown in the exemplification, one tail
straight and the other one bent permits of the same driver being used for stud driving
or slot driving, and the presence of an extra tail, when one only is used for driving,
serves in protecting the comparatively light set-screws from being accidentally engaged
by a driving stud on the face-plate, and the two tails may also be used at once,
in connection with two driving studs on a face-plate, as a means for equalized
driving.
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 :-
1. In a lathe driver, the combination, substantially as set forth, of a stock having
one or more driving tails and an eye, a pair of convergent set-screws, and a jaw
pivotted in the wall of the eye and presenting a serrated face into said eye opposite to
the set-screws.
2. In a lathe driver, the combination, substantially as set forth, of a stock provided
with one or more driving tails, and with an eye, a pair of convergent set-screws, a
recess in the wall of the eye opening toward one face of the driver, a cover-recess at
the open face of said first mentioned recess, a removable cover plate fitting said recess,
and a jaw pivotted in said first mentioned recess and presenting a serrated face in the
eye of the driver opposite to said set-screws.
3. In a lathe driver, the combination, substantially as set forth, of a stock provided
with an eye and with two opposite projecting radial driving tails one of which tails is
bent at right angles to the face of the driver, and one or more set-screws inserted
through the wall of the eye of the stock and projecting into said eye.
Dated this 21th dost of Santamber 1889
ALLISON BROS.,
Agents for the Applicant.