Improved Instrument for Centering Shafts and the like.
Year: 1896

page_text: Date of Application, 4th Apr., 1896-Accepted, 6th June, 1896
COMPLETE SPECIFICATION.
Improved Instrument for Centering Shafts and the like.
I ALPHONSE BORIOS of Vevey in the Canton of Vaud, Switzerland, Machine
Maker, 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 :-
This invention consists in the construction or arrangement of an improved instru-
ment or apparatus for ascertaining and marking the centre of the end surfaces of
shafts, bolts and other cylindrical pieces of machinery, and has for its object to
render this operation easy, quick and certain..
On the drawing appended hereunto Fig. 1 shows a top view of the improved
instrument and Fig. 2 a side view.
The instrument or apparatus serves to strike a centre mark in the end surfaces
of shafts and other cylindrical parts of machinery destined to be subsequently
turned in a lathe. It consists of a punch A held in a holder or guide I and pushed
upwards by a spring B, which holder is formed at the end of a flat sliding bar E
marked with a graduated scale on its upper side and adjustable in a guide C. The
latter preferably has an opening at the top one edge of which is marked as a vernier
to the scale on bar E, and the guide carries a square F of angle iron section. A
set screw D serves to fix the slide bar E in position in the guide C.
When the square is held against a shaft H, so as to touch it with both sides, the
distance of the centre of the shaft from the apex of the right angle formed by the
sides of the square is equal to the cathetus of an isosceles right-angled triangle of
which the diameter of the shaft forms the hypothenuse. The scale on bar E is
divided and marked with divisions having the same ratio to the divisions of an
ordinary measuring rule as the said cathetus to the hypothenuse and the zero mark
on the scale coincides with the zero mark on the guide C when the point of the
centre punch coincides with the apex of the square F.
The method of finding and marking the centre of a cylindrical body by means of
the improved instrument hereinbefore described is very simple. The diameter of
the cylindrical body is measured in any usual manner, the slide bar E is then
shifted till the zero mark on the guide C coincides with the division line on the
scale corresponding to the measure of the diameter and fixed in this position by
means of the set screw D. The square F is then held against the piece H to be
centered in the way shewn on the drawings and a blow with a hammer struck
upon the head of the punch A, which after the blow will be lifted off the piece
by the spring B.
Having now particularly described and ascertained the nature of my said inven-
ion and in what manner the same is to be performed, I declare that what I
claim is
1. The construction of an instrument for ascertaining and marking the centre of
he ends of cylindrical pieces of machinery substantially as herein before described
and illustrated by the drawings.

page_text: 2. The manufacture and use of an instrument or apparatus for centre-punching
-cylindrical pieces of machinery, constructed substantially as herein before described
.and illustrated by the drawings.
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.