A Sliding Centreing Tool.
Year: 1895

page_text: Date of Application, 6th July, 1895-Accepted, 10th Aug., 1895
A Sliding Centreing Tool.
I JONATHAN JACKS of 65 Upper Orwell Street, Ipswich, in the County of
Suffolk, Blacksmith, 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 :-
My invention relates to a self-contained tool or appliance by means of which
any object of a circular, oval, square, rectangular &c. configuration may be centred
with facility and exactitude.
"
"
In accordance with my invention I employ a frame slotted for the reception of
two main members which are free to travel backwards and be adjusted therein;
said slotted frame being formed with a fixed jaw at the operating or centreing
end. One of the movable members aforesaid hereinafter termed the "travelling
square has at the centreing end a projecting arm or head secured thereto, with a
divided scale to any standard of measurement along the edge. The other one of
the two movable members aforesaid, is also provided with a laterally projecting
head or jaw, the edge of its longitudinal stem being "scaled " in a similar manner
to the head of the "travelling square" aforesaid. To this latter is adapted-so
as to be free to travel to and fro' and be adjusted in position thereon, an adjustable
cross piece, gauging block or member fitted with a centre punch either with or
without spring according to the configuration of the object to be centred.
"""
18
Now, in using the above described device and taking by way of example the
case of a circular object-of say 1 inch diameter-introduced between the gripping
jaws of the device. Then, to arrive at the true centre, the "travelling square'
moved along till it reaches the indication of an inch on the scale marked on its
longitudinal stem and, having been fixed in position,-by a set nut or other suitable
means, the travelling cross piece or gauging block aforesaid is moved along till
the indication of an inch is reached on the scale; whereupon, by a tap being
given to the head of the centre punch aforesaid, a slight indentation will be made
by the pointed end of the punch in the object to be operated upon and the true
centre thereof be determined.
to half
When dealing with objects of oval &c. shapes, the movable gauging block
aforesaid would be set on the "scaled "head of the "travelling square
the measurement of the minor diameter of the object, the head of the "travelling
square" being set to one half the major diameter of the object to be operated
upon.
The preceding particulars have reference to centreing various objects to be
turned as in a lathe. My invention further consists in providing means for readily
determining the centre, longitudinally, of say a bar of metal. Under this head of
my invention, I employ a "saddle piece" secured by means of thumb nuts or
equivalents to the travelling square of the device, and in lieu of the gauging block
aforesaid. This "saddle piece" is so arranged that when secured in position, the
edge of its index arm will be in line with the head of the travelling square (see
Figure 3) so that, if the object to be longitudinally centred is 1 inch in diameter,
the edge of the index arm of the "saddle piece" will be in line with the inch
mark on the scale of the longitudinal stem of the second above referred to of the
two movable members; a "scriber " or the like is then drawn along the edge
of the index arm, whereupon the longitudinal central line will be delineated on the
object.

page_text: In the accompanying drawings illustrative of my invention
Figure 1 is a plan view of my improved device provided with the herein before
referred to projecting arm or head with adjustable cross piece and centreing punch,
to be used for centreing objects to be turned as in the lathe.
Figure 2 is an end elevational view of Figure 1,
"
Figure 3 is a plan view of my improved centreing tool with the "saddle piece
herein before referred to attached thereto, for effecting the longitudinally centreing
of various objects.
Figure 4 is a detached inside plan view of the "saddle piece" and
Figure 5 a detached elevational view of centre punch provided with a spring..
In the drawings a is the slotted frame with fixed jaw b. c is the "travelling
square," to which is attached the projecting arm or head d upon which latter works
the adjustable cross piece e, with centreing punch f. represents the second above
referred to movable member provided with the fixed jaw h. i is the "saddle
piece" herein before referred to (see Figures 3 and 4) secured to the "travelling
square" c. The saddle piece "i is provided with an index arm k and projection 1,
the latter serving as a guide in conjunction with the member m, to the object to be
longitudinally centred and thus keep same in position while being operated upon.
A similar projection n is formed at depending end of the projecting arm or head d
to serve as a guide in conjunction with the member m when the object is to be
centred for turning purposes.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I wish it to be under-
stood that I make no claim in respect of the slotted frame a or of the movable
member 9 with fixed jaw h but what I claim is :-
First. In sliding centrcing tools for objects to be turned in a lathe the employment
of the "travelling square c with projecting arm or head d, adjustable cross
piece e and centreing punch f
Second. In sliding centreing tools for longitudinally centreing objects, the
employment of the "travelling square" c, "saddle piece" i and index arm k.
Dated this 6th day of July 1895.
V. LAZARUS,
1 Furnival Street, London, E.C., Agent for Applicant.