Improvement in Engine Indicators.
Year: 1890

page_text: Date of Application, 24th Nov., 1890
Complete Specification Left. 20th Aug.. 1891-Accepted. 14th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvement in Engine Indicators.
I JOSEPH WILKINSON Engineer Church Road Hall Green near Birmingham
Worcestershire do hereby declare the nature of this invention to be as follows:-
Improvements in the part of engine indicators usually known as the parallel
motion that is the part that carries the pencil or pointer and is connected to the
pressure spring by a milled nut-This nut is usually made with a swivel or piece
with pivots or centers, and connected by links to the other parts of the parallel
motion.
I propose in this invention to substitute a ball & sockett joint in place of the
swivel or pivots and to prevent any slackness-draw the joints together with au
adjusting screw-The ball and socket can also be applied to the other joints of the
parallel motion-The object of this invention being to prevent any looseness of
joints and to have a perfectly even movement.
Dated this 21st day of November 1890.
JOSEPH WILKINSON.
COMPLETE SPECIFICATION.
Improvement in Engine Indicators.
JOSEPH WILKINSON Engineer Church Road Hall Green near Birmingham 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 engine indicator to which my improvement applies-are constructed in the
following manner-Two cylinders connected by a short arm-One of the cylinders
is for holding the diagram papers-the other is fitted with a piston & rod which are
actuated by the steam or gas when in use.
On the top of the piston rod a milled nut is screwed, with a swivel and links
connecting it to the part known as the parallel motion. (This carries the pencil or
pointer for marking the diagrams.
It is to the connection between the piston rod and this parallel motion that my
improvement applies.
I propose to use a ball-joint in place of the various forms of swivels now in use-
The ball can be solid on the milled nut or the ball can form the link or connecting
piece to the parallel motion-having concave piece on the milled nut to clamp
the ball.
I also propose to have a ball joint at the top end of links or connecting piece
(that is the end nearest the parallel motion). In all the modes of using the
ball-joint an adjusting screw or screws must be used to prevent all back lash and
take up for wear.
It will not always be necessary to have a ball-joint at both ends of links or
connecting piece in all cases but only for extra accuracy-The ball at milled nut
end being sufficient for most purposes.
The object of this invention is to overcome mechanical difficulties, Providing a
perfectly even movement with a minimum of shake or backlash-and enabling the
opperator to take up for wear by means of the adjusting screws.
The drawing Fig 1 represents side and end elevation of the parts intended to
apply the ball-joint.

page_text: A is the milled nut or screw having a ball solid on the top B two links with
concave pieces C tu clip on ball A.
D adjusting screw to draw the concave pieces on the links together against
the ball.
E part of parallel motion.
piston rod of indicator-tapped to suit screw part of milled nut A.
Fig. 2 elevation and plan of milled nut or screw A-formed concave with cap C
with two or more adjusting screws D. The link B is made with a ball at each end
to work in concave part of milled nut and in the parallel motion as in Fig. 3-or a
pin joint may be substituted for the ball at the parallel motion end.
Fig. 3 section end view and side elevation with the milled nut A having an
inturnal screw & hollowed to fit the ball B, this is held up and adjusted by the
screwed piece C-The ball can be solid on or fastened to connecting link D this
link having a ball or pin joint to connect it to the parallel motion E.
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
The use of a ball-joint, with the tightening or adjusting screws (substantially as
described) to connect the parallel motions with the pistons of indicators.
Dated this 19th day of August 1891.
JOSEPH WILKINSON.