IMPROVEMENTS IN LATHE CHUCKS
Year: 1865

page_text: LETTERS PATENT to James Buckingham, of Westmoreland House,
Walworth Common, in the County of Surrey, Engineer, for the Inven-
tion of "IMPROVEMENTS IN LATHE CHUCKS."-Partly a communication
from abroad by Charles Churchill, of New York, United States of
America.
Sealed the 17th April 1866, and dated the 28th October 1865.
PROVISIONAL SPECIFICATION left by the said James Buckingham at
the Office of the Commissioners of Patents, with his Petition, on the
28th October 1865.
I, JAMES BUCKINGHAM, of Westmoreland House, Walworth Common, in
the County of Surrey, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN LATHE CHUCKS," to be as follows:-
My Invention relates, first, to what are known as scroll chucks, being
universal chucks furnished with a scroll or snail on the one part, which being
rotated moves the dog jaws or gripping pieces simultaneously towards or from
the centre of the chuck. These chucks are practically limited to small chucks,
as the friction on the scroll movement is so great when the chucks are above
a certain size that sufficient bite cannot be imparted to the dogs to hold the
article desired to be chucked sufficiently tight.
Now according to my improvements I apply the scroll movement to chucks
of any size, and use such movement simply to move up the dogs and centre
the article to be chucked; in order to hold it when so centred, I furnish each
dog-with a binding screw inserted through the dog, and by which I nip the

page_text: article after it has been centred, the slightest possible turn of such binding
screw is sufficient, and I turn them by a key fitted to the head, which is sunk
within the dog. The point of the screw should not project except in the
actual pinch, and I form concentric rings on the points to prevent their com-
municating movement to the article so centred and chucked; the points should
be steel-hardened. The binding screws may have projecting heads if desired.
The second part of my improvements in chucks relates to universal chucks
with four or other even number of jaws more than four, and consists in dis-
posing such jaws in pairs opposed to each other, each pair being worked by
the same screw, rod, or shaft passing across the centre, and furnished with a
right-hand thread to operate the one jaw, while a left-hand thread operates the
other; with four jaws disposed at equal divisions of a circle the screw rods
are disposed at right angles to each other, and therefore cross at the centre
of the chuck, to do which they are disposed one behind the other, that is to
say, in different planes, but kept as close together as possible, for which purpose
they may be a little smaller at the crossing point than at any other. A suitable
key is used to turn the screw rods, moving each pair of dogs simultaneously.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Buckingham in the Great Seal Patent Office on the
28th April 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
BUCKINGHAM, of Westmoreland House, Walworth Common, in the County of
Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of October, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said James Buckingham, Her special licence that I, the said James Bucking-
ham, my executors, administrators, and assigns, or such others as I, the said
James Buckingham, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN LATHE CHUCKS," partly my own Invention, and partly a communication to
me from abroad by Charles Churchill, of New York, United States of America,

page_text: upon the condition (amongst others) that I, the said James Buckingham,
my executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said James Buckingham, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
My Invention relates, first, to what are known as scroll chucks, being
universal chucks furnished with a scroll or snail on one part, which being
rotated moves the dog jaws or gripping pieces simultaneously towards or from
the centre of the chuck. These chucks have been heretofore practically limited
to small chucks, as the friction on the scroll movement is so great when the
chucks are above a certain size that sufficient bite cannot be imparted to the
dogs to hold the article desired to be chucked sufficiently tight.
Now according to my improvements I apply the scroll movement to chucks
of any size, and use such movement simply to move up the dogs and centre
the article to be chucked; in order to hold the article when so centred, I
furnish each dog with a binding screw inserted through the dog, and by which
I nip the article after it has been centred; the slightest possible turn of said
binding screws is sufficient, and I turn them by a key fitted to the head, which
may or may not be sunk within the dog. The point of the screw should not
project except in the actual pinch, and I form concentric rings on the point
to prevent its communicating movement to the article so centred and chucked;
the points should also be steel-hardened. The binding screws may have
projecting heads if desired, but I prefer them to be sunk.
The second part of my improvements in chucks relates to universal chucks
with four or other even number of jaws more than four, and consists in dis-
posing such jaws in pairs opposed to each other, each pair being worked
by the same screw, rod, or shaft passing across the centre, and furnished
with a right-hand thread to operate the one jaw, while a left-hand thread
operates the other; with four jaws disposed at equal divisions of a circle, the
screw rods cross each other at right angles, and therefore cross at the centre
of the chuck, to do which they are disposed one behind the other, that is to
say, in different planes, but kept as close together as possible, for which purpose

page_text: they may be a little smaller at the crossing point than at any other. A
suitable key is used to turn the screw rods, moving each pair of dogs
simultaneously.
DESCRIPTION OF DRAWINGS.
Figure 1 represents a face view, and Figure 2 a side view of a scroll chuck
constructed and fitted according to my Invention, which as usually made and
well understood consists of a disc or plate a having radial slots b, in which
dogs c slide towards and from the centre of the plate, the simultaneous move-
ment of the dogs being effected by a scroll (seen dotted in Figure 1) taking
into teeth d formed on the under side of the dogs c, the scroll is formed on
the back plate e, which is fitted to rotate in plate a. In order to move and
adjust the dogs, plate a must be held fast while plate e is rotated by a lever
inserted in holes f, or vice versa, and great power is required even in very
small chucks to bring any considerable pressure of the dogs on the article
being chucked, and such as will hold it for the purposes required.
Now my Invention consists, as before mentioned, in the application of
pinching screws g in the dogs of scroll chucks, which renders them available
for chucking and holding articles of large sizes; with the application of these
screws I simply use the scroll to chuck the article concentrically, which the
movement of the dogs effects being moved simultaneously; having so centred
the article (the points of the dog screws g at the time being withdrawn
within the dog faces), I then proceed to fix it firmly by pinching the article
so chucked and centred by the three screws g, g, g, moving each one slightly
at a time, and so as not to disturb the centreing of the article.
In this way
articles may be quickly centred and firmly held in scroll chucks of large
size ; and even in small chucks these dog screws may be introduced with
advantage.
Figure 3 shows a separate side view of a dog c fitted with a binding screw,
the head of which is sunk within the metal of the dog, which arrangement is
in some respects of advantage.
Figure 4 represents a face view, and Figure 5 a side view of a universal
chuck with four jaws or dogs, the jaws i, i, k, k¹, being fitted to slide in
radial slots or grooves formed in the face plate l. The jaws of these chucks
are usually moved by independent screws all set in the same plane.
According to my Invention, I connect the opposing jaws in pairs by con-
necting or forming the two screws of such jaws in one, as m, m, p, p, the rods
of which they are formed passing across the centre of the chuck as seen; to
admit of this and the employment of four jaws, I dispose the screws

page_text: m, m, and p, p, in different planes (see red lines in Fig. 5), otherwise the
jaws and screws are fitted in the chuck plate much in the usual manner, and
will not require particular description. The screw cut on one end of m to
actuate jaw i is (say) a right-hand thread, while that to actuate i¹ will be a
left-hand thread; in like manner the screw cut on one end of p to actuate k
will be a right-hand thread, while that on the other end to actuate k¹ will be
a left-hand thread. In this way, by turning one end of m both dogs i, i¹, will
be moved, and p in like manner will operate both jaws k, k¹, separating or
bringing them together simultaneously in pairs, as will be readily understood,
and so chucking and holding the article as required. On the screw rods
m, m, p, p, I form collars r, r, which take the bearing and thrust of the jaws,
but reduce the rods m and p where they cross to the smallest dimensions con-
sistent with strength, in order to get the planes (see red lines Figure 5) as
close together as possible. Where six dogs are employed the three different
pairs of screws must of course be in three different planes, and it would be
necessary to reduce the collars r, r, or perhaps to dispose them (those on the
third screw rod at least) near the heads or extreme ends, as will be readily
understood. The general fitting of the parts of the chuck I have not thought
necessary to describe, as being otherwise well known.
Having described the nature of my Invention and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent is,―
First, fitting and applying pinching and binding screws g to the dogs or
jaws of scroll chucks, as and for the purposes herein-before described.
Secondly, fitting and furnishing universal chucks with two or more pairs of
jaws, each pair of jaws being operated simultaneously by a single screw rod
arranged and applied in manner herein-before described.
In witness whereof, I, the said James Buckingham, have hereunto set
my hand and seal, this Twenty-seventh day of April, in the year of
our Lord One thousand eight hundred and sixty-six.
Witness,
W. CLARK,
Patent Agent,
58, Chancery Lane,
London.
JAMES BUCKINGHAM. (L.S.)