IMPROVEMENTS IN DOG AND DRIVER LATHE CHUCKS
Year: 1884

page_text: I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN DOG AND DRIVER LATHE CHUCKS a communication to me from abroad by
Samuel N. Silver of Auburn, in the County of Androscoggin and State of Maine,
United States of America, Gentleman to be as follows:-
"
This Invention relates to a new and improved automatic lathe dog and driver
whereby the strain is equalized on the opposite sides of the work and lathe centre
so as to prevent the springing of the shaft by being wedged on one side of the
lathe centre.
The driver is an annular casting provided with two diametrically opposite
jaws between which the dog or carrier fits. The driver is held to the face plate
of the lathe by a single bolt passing through the edge of the driver at a point
equi-distant from the two jaws.
This bolt is not drawn up very tight so as to allow the driver to move slightly
on the face plate, the said bolt serving as a fulcrum.
The driver need not move very freely but only a very short distance, that is, just
enough to make up the distance the dog or carrier is thrown out of centre on
account of any unevenness of the bar or rod that is held by it.
The dog or carrier is placed on the shaft or other work to be turned and
when the shaft is on the centres, the dog is placed between the jaws of the driver
and the set screw of the dog is then drawn up tightly.
The lathe is started and turns the face plate which turns the driver, and this
adjusts itself instantly and automatically as it is pivoted at one side, so that each
jaw presses equally on the parallel sides of the dog, whereby an equal strain on
the opposite sides of the lathe centre is obtained and springing of the shaft is
prevented.
The dog or carrier may either be the ordinary apertured plate with set screw,
but having parallel sides to fit between the jaws of the driver, or it may be what
is known as a bitch doc

page_text: The objection to the common bitch dog as now used is that it takes too long to
turn the screw out so as to get it off the work.
The bitch dog is to be used when the work is of such kind as to make it
desirable to remove the dog without taking the work off the lathe, and to
enable this to be quickly done the two gripping jaws which constitute the dog
are connected at their opposite ends by screw bolts pivoted each at one end to the
end of one jaw and received in a slotted lug at the corresponding end of the
other jaw against which the tightening nut on the pivoted screw bolt bears.
With this construction, the two parts of the dog may be readily connected and
disconnected. The driver can be used without either of the dogs in case a pulley
or similar object is to be turned off.
The two projecting jaws of the driver when made of proper length come against
the opposite arms of the pulley and by means of the fulcrum in the rim of the
driver it automatically adjusts itself to the pulley arms so as to bear alike on each,
which prevents chattering.

page_text: COMPLETE SPECIFICATION.
"
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN DOG AND DRIVER LATHE CHUCKS (a communication to me from abroad by
Samuel N. Silver of Auburn, in the County of Androscoggin, and State of Maine,
United States of America,) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to a new and improved automatic lathe dog and driver
whereby the strain is equalized on the opposite sides of the work and lathe centre
so as to prevent the springing of the shaft by being wedged on one side of the
lathe centre.
Reference is to be had to the accompanying drawings forming part of this Specifi-
cation in which similar letters letters of reference indicate corresponding parts in
all the figures.
Figure 1 is a face view of my improved lathe dog. Figure 2 is a cross sectional
view of the same on the line ac Figure 1. Figure 3 is a face view of the same
with a lathe dog in the face plate. Figure 4 is a cross sectional elevation of the
same on the line y, y Figure 8.
The driver A is an annular casting provided with two diametrically opposite
strong jaws B, and with two diametrically opposite lugs C formed on the edge;
the axis of the lugs C being at right angles to the axes of the jaws B.
The driver A is beld to the face plate D of the lathe by a bolt E passed from
the inner side of the face plate D through a slot F into one of the lugs C.
The driver A is provided with a central aperture corresponding with the aperture
in the face plate D.
The dog or carrier G provided with a central aperture fits closely between the
jaws B and rests in a recess A' of the driver A. and the carrier G is provided with
the usual set screw H which is situated at the end furthest from the screw E so as
to balance the carrier G.
The bolt E is not drawn up very tight so as to allow the driver A to be moved
slightly on the face plate D, the said bolt serving as a fulcrum.
The driver A need not move very freely but only a very short distance that is
just enough to make up the distance the dog or carrier is thrown out of centre on
account of any uneveness of the bar or rod that is held by it.
The dog or carrier G is placed on the shaft etc to be turned and when the shaft
is on the centres the dog G is placed between the jaws B of the driver A and the
Bet screw H is then drawn up tightly.
The lathe is started and turns the face plate D which turns the driver A and this
adjusts itself instantly and automatically as it is pivoted by the bolt E so that
each jaw B presses equally on the parallel sides of the dog G whereby an equal
strain on the opposite sides of the lathe center is obtained and springing of the
shaft is prevented.
In figures 3 and 4 I have shown a bitch dog K. held between the jaws B.
The objection to the common bitch dog as now used is that it takes too long to
turn the screw out so as to set it off the work

page_text: The bitch dog K is to be used when the work is of such kind as to make it
desirable to remove the dog without taking the work off the lathe.
The driver A can be used without either of the dogs in case a pulley or similar
object is to be turned off.
The two projecting jaws of the driver A when made of proper length come
against the opposite arms of the pulley and by means of the fulcrum in the rim of
the driver A it automatically adjusts itself to the pulley arms so as to bear alike
on each which prevents chattering.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
1. A lathe dog consisting of an apertured plate held loosely between the two
jaws of a driver pivotally connected to the face plate of the lathe, substantially as
herein shown and described.
2. The combination with the face plate of a lathe of a driver provided with
two opposite jaws and held on the face plate so as to have a slight movement on
the same and of a dog or carrier held loosely between the above mentioned jaws
substantially as herein shown and described.
3. The combination with the face plate of a lathe of a driver provided with
two opposite jaws and held on the face plate to have a slight movement on the
same, and of a bitch dog H, held 'loosely between the jaws of the driver sub
stantially as herein shown and described.
4. The combination with the lathe face plate D having slots F of the driver A
provided with jaws B, and of the dog G held loosely between the jaws B substantially
as herein shown and described.