Centreing, or Setting out Engineering and other work.
Year: 1886

page_text: Date of Application, 27th Sept., 1886.
Complete Left, 15th June, 1887.
Complete Accepted, 15th July, 1887.
Centreing, or Setting out Engineering and other work.
I FREDERICK WILLIAM MUNRO, of No. 82 Saint Thomas Road, Finsbury Park,
London, N. Electrician, do hereby declare the nature of this invention to be as
follows:-
The device according to my Invention consists of two narrow slotted arms, prefer-
ably of metal, one placed above the other, and through the slots of which, passes up
a suitable clamping screw, for securing them in any desired position. At one end of
each of the slotted arms aforesaid, is furnished a pair of wing pieces mounted upon
a central pin, and free to move to the position, and for the purpose, hereinafter
described.
When the device according to my Invention is required to be used for the purpose
of guaging the centre of any given article, the clamping screw aforesaid is loosened,
and moved along the arms to a point at, or as near as possible to, the half of the
diameter of the article to be centred, the two wing pieces, at the outside ends of the
arms are then dropped, when they take up such a position, as shall enable them to
slide freely round the outside surface of such article, say for instance a cylinder head.
Through the clamping screw aforesaid is passed a small pin or "scribe," which is
kept pressed down upon the article to be centred, by a surrounding spiral spring,
taking its bearing upon a shoulder formed upon the said pin or scribe. When the
instrument is moved round the article, a small circle is described, the centre of which
is easily determined.

page_text: Should it be desired to use the device as a T square, one of the arms aforesaid is
simply placed centrally upon the end of the other and screwed tight.
The slotted arms aforesaid may be made of any desired length, and their edges have
scales formed thereon: they may also be furnished with wire and plate guages.
When not required to be used, on releasing the nut on the top of the clamping
screw aforesaid, the one slotted arm may be readily rotated upon the central pin, and
superposed upon the under arm, so as to allow of the device being readily carried in
the manner of an ordinary flat rule.
Dated this Twenty third day of September 1996
JAMES
STEVENSON,
Gray's Inn Chambers,
20, High Holborn, London, W.C.,
Agent for Applicant.

page_text: Centreing, or Setting out Engineering and other Work.
I, FREDERICK WILLIAM MUNRO of 82 Saint Thomas Road, Finsbury Park,
London, N., Electrician, 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 :-
The appliance in accordance with my Invention is devised with a view to facilitate
the measuring, centreing, marking or setting out of engineering and other work.
In order that my Invention may be the better understood I have appended the
accompanying sheet of drawings in which :-Figure 1 is a plan of the Instrument or
Appliance when closed. Figure 2 is a side elevation of the same, Figure 3 is a plan
of the underside of one plate or arm shewing the wing pieces, hereinafter referred to,
when closed. Figure 4 is a plan of the underside of the second plate or arm with the
wing pieces in a similar position. Figure 5 is a side elevation of one arm, shewing
wing piece dropped, in position for determining centres. Figure 6 shews the device
arranged as a T square. Figure 7 represents the application of the device in
accordance with my Invention for finding the centre of for instance a cylinder cover.
Figure 8 is the clamp nut of a sliding clamp screw hereinafter referred to. Figure 9
is a section of the sliding clamp screw, shewing internal pin and spring. Figure 10
is a section of the sliding clamp screw taken on line A. B figure 9; and, Figure 11 is
a detailed view of the wing piece before referred to. Like letters of reference denote
corresponding parts in the several figures.
Said
The device according to my invention consists of two narrow slotted plates or
arms a. a preferably of metal, placed one above the other. Through the slots b. 6¹ of
the plates or arms a. a¹ is passed a clamp screw Figure 9. formed with a square body e
figure 10, in order to enable it to move freely within and along said slots 6. 6' without
turning, and upon which is screwed the nut f. figure 8, thus enabling said plate a. a¹
to be secured in any desired position at right angles to each other. The clamp screw
above referred to is drilled and recessed to receive a pin or scribe h. having near its
centre a shoulder h' and which is kept in position by means of the spring i.
spring i. may be used either to keep the point of the scribe pressed down upon the
object upon which the instrument is being used, or pressed up into the clamp screw, to
protect the point from injury, in which latter case the scribe would, when required to
be used, be pressed down by the finger. At one end of each of the said slotted plates
or arms a. a² is provided a pair of wing pieces g. g¹ shown more particularly in the
detailed view figure 11, mounted upon a central pin, or if desired said wing pieces g. 9'
may be attached to the plates or arms a. a' by a rule joint or equivalent means.
wing pieces g. 9' are maintained in the position required, by a strong flat or equivalent
spring c. fixed in any suitable manner to the upper faces of the aforesaid slotted plates
or arms a. a' and bearing or pressing firmly upon the pinned or hinged ends of the
said wing pieces.
Said

page_text: The slotted plates or arms a. a¹ aforesaid may be of any desired length and their
faces or edges have divided or graduated scales marked thereon; they may also be
provided with wire guages j. j. and plate guages k. k.
The mode of manipulating the instrument above described is as follows, that is to
say:-
-When it is desired to use the instrument as a T square, the nut f. is loosened
and the upper plate or arm aris moved along the lower plate a¹ until the square body e
of the clamp screw enters the end of the slot at a where it is free to rotate; said upper
arm a is there turned to a position at right angles to the lower arm a¹. In this position
the upper arm a. aforesaid is moved along the lower arm a¹ to a point near its centre,
when the nut f. is screwed tight, and the instrument is ready for use. To prepare it
to be used as a set square, the upper plate or arm a is moved and secured by means of
the aforesaid nut f to the other extremity y of the lower plate or arm a¹.
When the device in accordance with my Invention is required to be used for the
purpose of centreing any given object the nut. aforesaid is loosened and the clamp
screw moved along the slots b. 6 of the arms a. a¹ to a position at or as near as possible
to the half of the diameter of the article m. to be centered, as shown at figure 7. of
the accompanying drawings, the wing pieces g. g¹ are now dropped taking up a position
at right angles to the arms to which they are attached, in which position they are firmly
held by the springs c. c. hereinbefore referred to, and serve as guides to the instrument
when centreing any article, as for instance a cylinder head. The instrument is now
moved round the article m. at the same time that the scribe or pin h. which extends
through a perforation in the nut fis depressed, and in its travel marks a minute circle,
the centre of which can easily be determined.
When not required to be used, the nut f of the clamp screw is loosened, the upper
arm is moved along the lower until said clamp screw enters the before mentioned
circular part . when the arms may be rotated and superposed one upon the other, the
clamp screw may then be moved into any desired position, and the nut f. again screwed
tight, and the device may then be carried conveniently in the pocket in the manner of
an ordinary flat rule.
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 :-
The novel appliance for the purposes of marking, measuring, centreing or setting
out engineering and other work, substantially as herein set forth.
Dated this 11th day of June 1887.
JAMES
STEVENSON,
Gray's Inn Chambers,
20, High Holborn, London, W.C.,
Agent for Applicant.