Improvements in or relating to Apparatus for Recording Motion Diagrams.
Year: 1899

page_text: Date of Application, 5th July, 1899-Accepted, 9th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in or relating to Apparatus for Recording Motion
Diagrams.
I, CHARLES THOMAS CROWDEN, Engineer, of Motor Works, Leamington, in the
County of Warwick, 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 relates to apparatus for the taking of motion diagrams, and has
for its object to enable an apparatus such as is usually employed for the taking
of steam diagrams to be utilised to obtain from an engine or machine in actual
service diagrams showing the motion of the valves, or other moving parts thereof.
The usual steam cylinder and parts of an indicator can be used under steam
for the obtainment of pressure and volume diagrams in the usual manner, whilst
according to this invention a supplementary set of parts can be applied to the
indicator to enable it to produce motion diagrams without the use of steam in
its cylinder.
In the accompanying drawings
Figure 1 is a sectional elevation of a steam engine indicator modified according
to this invention.
Figure 2 is an example on a reduced scale of a diagram taken from a valve
motion by this apparatus.
To any convenient support A a bracket B is clamped carrying a short length of
tube C closed at the bottom, the upper end of which is screw-threaded and fixed
to the lower part of the indicator cylinder D, by the nut E. The preferred form
of indicating apparatus comprises a cylinder D containing a piston F with
piston rods FF passing out at each end of the cylinder. One of these rods F1
operates through the links G¹ G G in the usual manner the marker carried on
the lever G; the other piston rod F2 is attached to the underside of the piston F
and is connected by the cord H to the valve spindle or other moving part whose
motion is to be recorded; if necessary through some reducing gear. The cord H
is passed round the pulley H' which is mounted upon the swivelling socket Ha
pivotted to the bottom of the tube C. The ordinary indicator spring is replaced
by or may itself be used as a compression spring J which is attached to the
underside of the piston F or to the detachable rod F, and is of sufficient strength
and arranged so as to maintain the cord H in tension; or a tension spring or
equivalent may operate upon the other side of the piston F or rod F¹.. Instead
of the cylinder D with its piston and two rods 11 F2 a single rod may be
employed connected at one end to the link G¹ at the other to the part whose
motion is to be recorded, and constrained to move endways by means of suitable
guides, means being provided if necessary to keep the connection, if flexible,
always in tension. It is found, however, more convenient to modify the cylinder
and parts as above described, than to replace them by such a rod: The tube C
is preferably open at one side, as shown, in order to facilitate the cord H being
fastened to the rod F2.
A spring-controlled drum K forms a rotary record-carrier and is pivotted to a
bracket Di fixed to the cylinder D; it is adapted to carry the cards upon which
the record is to be made, the drum being operated in the usual manner by means
of a cord Lattached to say the cross-head either direct or through some reducing
as may be convenient.
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page_text: The cord H may be replaced by a rod connected directly to the piston F and
coupled to the reducing gear or to the moving part itself provided the total
length of movement of the latter does not exceed the normal stroke of that piston.
When this rod is used it will pass up through the bottom of the tube C and will
necessitate less alteration in the indicator than docs the use of the cord H; for
the indicator spring may remain in the position it occupies when the piston is
operated by steam, or may be dispensed with altogether.
The apparatus is arranged so that the marker of the indicator occupies a mean
position when the valve or other indicated part is in a central position; on now
putting the engine or apparatus in motion, the marker will record the actual
movements of that part. The card on which the diagrams obtained from valve
motions are recorded may.conveniently have the steam ports marked upon it
as shown at M Figure 2, and may also be used for receiving the horse-power
diagrams; thus allowing the two diagrams to be superimposed; both of which
may be taken by the same apparatus.
:
3
When taking motion diagrams by this apparatus the marker is preferably held,.
either before or after the diagram is taken, in a central position by means of a
lever, stud or equivalent device so as to obtain a centre line on the diagram card
which corresponds to the atmospheric line on a horse power' indicator card..
If desired card cylinders and. marker gears may be operated in. the above
described manner by any two or more parts, of a machine having relative motion
in.order. to obtain graphic records of this motion.
Such records of motion would for instance be very valuable in determining
the necessary adjustments in machines' in which cams or complex linkages are
employed.
T
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 le
:
1.
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1. A double purpose steam engine indicator comprising the usual steam
cylinder and parts and a supplementary set of parts whereby the indicator can be
operated with or without the use of steam in its own. cylinder.
3. A steam engine indicator comprising a record carrier rotated from one
moving part of an engine or other mechanism, a marker reciprocated in a plane
parallel to the axis, of the rotating carrier, a cylinder, spring, piston, and piston
rod respectively such as D J F and a detachable piston-rod such as F and.
means such as the cord H for connecting the piston with a second moving part of
the engine or other mechanism substantially as described.
3. A. steam engine indicator comprising a record. carrier rotated from one
moving part of an engine or other,mechanism, a marker reciprocated in a plane
parallel to the axis of the rotating carrier, a cylinder, piston and piston-rod
respectively such as D F and F, a detachable piston rod such as. F and means for
connecting the piston with a second moving part of the engine or other mechanism
substantially as described.
4. The combination with a steam engine indicator of ordinary construction' of
an additional piston-rod such as Fa with or without a spring such as J and with a
flexible or rigid connection between the piston rod F2 and a moving part of an
engine or mechanism substantially as described.
5. The complete apparatus for recording motion diagrams substantially as
described and illustrated in Figure 1 of the accompanying drawings..
CHARLES THOMAS CROWDEN.
Boult & Wade;
Agents for the Applicant.