Improvements in Tool Posts.
Year: 1891

page_text: Date of Application, 8th May, 1891-Accepted, 13th June, 1891
COMPLETE SPECIFICATION.
Improvements in Tool Posts.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Anson Groves Ronan, of the City of
Toronto, in the County of York and Province of Ontario, Canada, Machinist,)
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My invention relates to an improved tool post for lathes, planers, shapers and all
such machinery as require a tool to be securely held to cut the metals and other
substances worked by such machinery, and the objects of my invention are ;-first, to
provide a tool-post or holder whereby a tool can be held secured at any angle within
a reasonable limit of inclination to the work, thereby enlarging the range of work
possible to be performed by a single tool, both as regards the different side and other
cuts in the same metal and the proper inclination or rake peculiar to the different
metals; second, to provide a tool-post whereby the same tool can be used to cut
both left and right hand threads of the same or different and various pitches; and
third to provide a tool post affording a more ready adjustment of the tool than the
ordinary posts in use heretofore.
I attain these objects by means of the device illustrated in the accompanying
drawings in which similar numbers of reference refer to similar parts throughout,
and
Fig. 1, represents a side elevation of my improved tool-post at the position giving
the tool secured therein the greatest rake.
Fig. 2, represents the vertical section at the central axis of the post in the same
position as the foregoing figure, but having the tool removed.
Fig. 3, represents the front elevation of the post adjusted to cut a left hand
thread where only a medium height of the point of the tool is necessary, or less
rake desirable.
Fig. 4, represents a partial vertical section at centre line of an alternative
arrangement of the bed and bolster-rings inverted from that shown in Fig. 2,
and-
Fig. 5, represents the bolster-ring inverted to more fully illustrate its shape.
The tool-post, 1, resembles ordinary posts in the respects of having a similar set,
or clamping screw, 2, tool-mortice, 3, and footing, 4, by which latter it is main-
tained in position in the jaws, 5, of the slide-rest of a lathe, or corresponding device
for the same purpose in other machines. The essential difference in my improved
post being that of having a universal or ball-socket joint, 6, therein a convenient
distance below the tool-mortice, 3, and from the centre of which joint, 6, the upper
portion of the said post, 1, can be inclined in any direction, to an extent to meet
the requirements usually desirable or necessary. The post it will be observed is
made in two distinct parts; the upper portion having an enlargement at its lower
extremity in which the socket is formed in the shape of a cylindrical hole terminating
in a dome or hemispherical shape. The lower or footing portion, 4, is formed with
a head to engage the jaws, 5, of the slide rest similarly as other tool-posts heretofore
in use, but the shank portion, 7, has a ball, 8, formed on the end of it of a diameter
to fit neatly into the socket formed in the upper portion of the post next hereinbefore
described.
For the rigid support of the cutting tool, concave and convex rings are employed,
and consist of the bed-ring, 9, and the bolster-ring, 10, either of which may have a
hemispherical or half-ball shaped projection, 11, on it and the other ring a corre-
sponding hemispherical cavity, 12, to receive and closely fit the said half-ball, 11.
3

page_text: The bed-ring, 9, has an axial opening 13, to admit the tool-post, 1, therein
and allow it to incline in any direction. The centres of the bed and bolster-
rings, 9, and, 10, are essentially as closely as practicable, the same as that of
the ball socket joint, 6, in the tool-post, 1.
Preferably the bed-ring, 9, is formed considerably thicker at one side than
diametrically opposite, by having preferably its lower side cut oblique to the axis
of formation heretofore, and on which the hemispherical or convex projection, 11,
or the cavity, 12, was formed.
The flange, 14, is provided for the purpose of forming a rigid and positive support
for the bolster-ring, 10, to rest on, below the cutting tool.
The bolster-ring, 10, is about the same diameter as the said bed-ring, 9, and has
an axial opening through it to admit the tool-post, 1, therein, freely, and when the
convex projection, 11, is formed on the bed-ring, 9, the said bolster-ring, 10, has
the corresponding cavity, 12, formed in its under side. The reason of the above
condition is that I can form the cavity, 12, in the bed-ring, 9, as in Fig. 4, which
exhibits this alternative. Further than the reversed condition of the rings, 9
and 10, in Fig. 4, I form the rests or calks, 15, (shown in Figs. 1, 2, and 4, as on
the bolster-ring, 10, and resting on the flange, 14) on the bed-ring, 9, instead, which
would possess the advantage of not forming a rest for dirt, chips and other
objectionable substances to get into the joint when the said cavity, 12, exists in the
bed-ring, 9.
The calks, 15, are for the purpose of forming a rigid support and a positive
security where a liability exists for the rings, 9, and, 10, to frictional slip on one
another, under the pressure exerted by a heavy cut on the tool.
In the alternative forms for the top of the bolster-ring, 10, shown by Fig. 4,
and the three preceding figures, I form a tool channel, 16, for the purpose of
causing the said bolster-ring, 10, to turn with the tool, so as to maintain one
of the calks, 15, always beneath the tool to receive the pressure and rest on the
flange, 14.
The said calks, 15, are not an essential necessity for I may dispense with them
entirely as the grip of the frictional contact between the said rings, 9, and, 10, is
sufficient I find under all ordinary circumstances to maintain the post, 1, and tool in
pòsition without slipping, and in posts for small machines they can be dispensed
with. When the calks, 15, are employed it is preferable to form them so that both
cannot rest on the flange, 14, at once, but that a small space exists beneath the one
at the rear side from the work, when the tool has been properly set.
In using my improved tool-post the amount of rake and height of the tool point
can be regulated and adjusted by turning the rings, 9, and, 10, on one another in
different relation, as shown by Figs. 1, and 3, the latter bringing the tool horizontal.
Also by turning one of the rings a half circle and keeping the other fixed, from the
position shown in Fig. 1, the point of the tool can be depressed to the lowest level
and give least rake; or, by reversing the tool through the post and turning all
bodily round a half circle, would give the same result.
I anticipate that a tool-post having a joint such as two engaged rings or links
like a chain can be inclined in any direction similarly to the ball-socket joint I
employ, but the link joint has the disadvantage of only a point or limited line of
contact and consequent increased wear.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
Claim, 1-A tool-post or tool-holder having a joint therein as a means whereby
it can be inclined, for the purpose herein before set forth.
Claim, 2-In a tool-post or tocl-holder the bed-ring encircling said post and
having its upper and lower plane surfaces oblique to one another, and a bearing
formed on its upper side to fit the bolster-ring supported thereon, substantially as
shown and described.

page_text: Claim, 3-In a tool-post or tool-holder the bolster-ring encircling said post and
having a bearing formed on its lower side, to fit over the bed-ring hereinbefore
claimed, substantially as shown and described.
Claim, 4-In combination, the tool-post or tool-holder having a joint therein as a
means whereby it can be inclined, a bed-ring encircling said post and having its
upper and lower plane surfaces oblique to one another, and a bearing formed on its
upper side to fit the bolster-ring supported thereon, substantially as shown and
described.
Claim, 5-In combination, the tool-post or tool-holder having a joint therein as a
means whereby it can be inclined, a bed-ring encircling said tool-post and having
the form hereinbefore specified, and a bolster-ring encircling said post and having a
bearing formed on its lower side to fit over the bed-ring, substantially as shown
and described.
Claim, 6-In combination, the tool-post or tool-holder having a joint therein for
the purpose hereinbefore described, a bed-ring encircling said post and having the
form hereinbefore specified, a bolster-ring also encircling said tool-post and having
the form as hereinbefore specified, the diametrical tool channel across the top side
thereof, and the calks on a corresponding diametrical line across the bottom of said
bolster-ring, substantially as shown and described.
Dated this 8th day of May 1891.
ALLISON BROS.,
Agents for the Applicant.