Improvements in Vacuum Regulating Apparatus for Milking Machines.
Year: 1892

page_text: Date of Application. 3rd May, 1892
Complete Specification Left, 3rd Feb., 1893-Accepted, 1st Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in Vacuum Regulating Apparatus for Milking
Machines.
I, ALEXANDER SHIELS, of 190 Bath Street, Glasgow, M.B.C.M., B.Sc., do
hereby declare the nature of this invention to be as follows:-
This invention relates to milking machines, and it has for its object to regulate
the vacuum pressure in such machines.
In pulsating machines, that is to say, in machines where the vacuum pressure on
the teat cups, is made to rise and fall, say, by way of example, from a maximum
of 15 degrees, to a minimum of 5 degrees, it is essential that the vacuum should never
fall below the minimum, as, if it does so, the teat cups will not cling to the cow's
teats with sufficient strength to retain them in position, should the cow jerk or
move about. Also it is essential in such machines, to have the pulsations as regular
and decided, as possible.
The improved regulating apparatus, is designed to keep up a regular and steady
pulsation, which shall be effective in all ordinary circumstances, and in which the
vacuum is not allowed to fall so low, as to permit the teat cups to readily fall off
during the milking.
In carrying out my invention, I connect a pipe from the vacuum reservoir, to a
piston or plunger valve. The piston or plunger reciprocates in a tubular or other
casing or cylinder, which may be closed by a screw cap, through which works the
piston rod. The piston rod is guided in its up and down movements, by a bearing
secured in a bracket, which is cast in one with a vertical standard or pillar. To
the piston rod is connected, adjustably, a connecting rod, the upper end of which is
fitted, adjustably, in or to a disc wheel, which is carried on a short horizontal
shaft revolving in bearings on the upper end of the standard. The shaft may be
revolved by gearing, actuated either by hand or by power. The revolutions of the
shaft cause the piston or plunger to reciprocate in the casing or cylinder. The
passage ways in the cylinder or casing of the valve, are made in the form of a long
narrow slot, made with a widened out, preferably circular, part at its upper end. .
The object of making the passage way in this peculiar shape, is to allow the..
vacuum to be gradually cut off or turned on at each reciprocation of the piston.
Instead of having a long slot for the passage way, a series of holes, or equivalent,
may be substituted.
As the vacuum in the pipe connection leading to the teat cups, falls very
gradually when the reciprocating piston descends, and, as it is possible, or may
happen, that the vacuum may not fall to the minimum before the piston or plunger
again rises, I provide, on said pipe connection, a vacuum reducing valve which is
normally closed against its seat by means of a spring or weight. The spindle of
the valve is or may be guided in a perforated disc or bridge fitted in the valve
casing. Fitted in connection with the vacuum valve is a air admission valve.
which may be in the form of a diaphragmn bearing on the end of the metal tube as
The air admission valve is or may be opened and closed synchronously
with the reciprocations of the piston or plunger by means of a connecting lever or
chain which is raised and lowered by the action of a cam or pin wheel and lever.
When the vacuum is to be reduced in the pipe connection leading to the teat cups
the air admission valve and vacuum valve are operated automatically so as to admit
the air to said pipe connection and thereby reduce the vacuum until it reaches the
minimum when the valve at once closes.
a seat.
In case the vacuum in the pipe connection leading to the teat cups should at any
time fall below. the minimum a valve capable of opening automatically under such
:

page_text: conditions is provided. This valve is fitted on a loop or junction pipe which
connects the pipes on both sides of the pulsating piston. This valve which is of
the same or substantially the same construction as the vacuum reducing valve is so
arranged as to open' against. the action of a spring or weight immediately the
vacuum at the teat cups falls. below 'the minimum.
66
I may use for the vacuum regulating valves in conjunction with this machine
Shiels and Elliot" reducing valves.
Dated this 2nd day of Max 1800
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent..
1
COMPLETE SPECIFICATION. ·
Improvements in Vacuum Regulating Apparatus for Milking
Machines.
I, ALEXANDER SHIELS, of 190 Bath Street, Glasgow, M.B.C.M., B.Sc., 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 milking machines, and it has for its object to regulate
the vacuum pressure in such machines.
In pulsating machines, that is to say, in machines where the vacuum pressure on
the teat cups, is made to rise and fall, say, by way of example, from a maximum of
15 degrees, to a minimum of 5 degrees, it is essential that the vacuum should never
fall below the minimum, as, if it does so, the teat cups will not cling to the cows'
teats with sufficient strength to retain them in position, should the cow jerk or
move about. Also it is essential in such machines, to have the pulsations as regular
and decided, as. possible.
The improved regulating apparatus, is designed to keep up a regular and steady
pulsation, which shall be effective in all ordinary circumstances, and in which the
vacuum is not allowed to fall so low, as to permit the teat cups to readily fall off
during the milking.
In carrying out my invention, I connect a pipe from the vacuum reservoir, to a
piston or plunger valve. The piston or plunger reciprocates in a tubular or other
casing or cylinder, which may be closed by a screw cap, through which works the
piston rod.
The piston rod is guided in its up and down movements, by a bearing
secured in a bracket, which is cast in one with a vertical standard or pillar. To
the piston is connected, adjustably a connecting rod, the upper end of which is
fitted, adjustably; in or to a dise wheel, which is carried on a short horizontal shaft
revolving in bearings on the upper end of the standard. The shaft may be revolved
by gearing, actuated either by hand or by power. The revolutions of the shaft
cause the piston or plunger to reciprocate in the casing or cylinder. The passage
ways in the cylinder or casing of the valve, are made in the form of a long narrow
slot, with a widened out, preferably circular, part at its upper end. The object of
making the passage way in this peculiar shape, is to allow the vacuum to be
gradually cut off or supplied at each reciprocation of the piston. Instead of
having a long slot for the passage-way, a series of holes, or equivalent, may
substituted therefor.
be
As the vacuum in the pipe connection leading to the teat cups falls very gradually,
when the reciprocating piston descends, and, as it is possible, or may happen, that
the vacuum may not fall to the minimum before the piston or plunger again rises,
I provide, on said pipe connection, a vacuum reducing valve which may be closed
against its seat by means of a spring or weight. The spindle of the valve is or
may be guided in a perforated disc or bridge fitted in the valve casing.
Fitted in connection with the vacuum valve is an air admission valve which may
be in the form of a diaphragm bearing on the end of the metal tube, as a seat.

page_text: The air admission valve is or may be opened and closed synchronously with the
reciprocations of the piston or plunger by means of a connecting lever or chain
which is raised and lowered by the action of a cam or pin wheel and lever. When
the vacuum is to be reduced in the pipe connection leading to the teat cups the
air admission valve and vacuum valve are operated automatically so as to admit
the air to said pipe connection and thereby reduce the vacuum until it reaches the
minimum when the valve at once closes.
In case the vacuum in the pipe connection leading to the teat cups should, at any
time, fall below the minimum a valve capable of opening automatically under such
conditions is provided. This valve is fitted on a loop or junction pipe which
connects the pipes on both sides of the pulsating piston. This valve which is of
the same or substantially the same construction as the vacuum reducing valve is so
arranged as to open against the action of a spring or weight immediately the vacuum
at the teat cups falls below the minimum.
I may use for the vacuum regulating. valves in conjunction with this machine
"Shiels & Elliot" reducing valves as described in the Specification of my prior
Patent No. 20889 of 1891.
And in order that my said invention may be properly understood, I have hereunto
appended two explanatory sheets of drawings, whereon :—
Fig. 1 is a vertical section of the apparatus.
Fig. 2 is a front elevation of the apparatus.
Fige. 3, 4, 5 and 6 are detail views.
Referring to the drawings, whereon the same reference letters, wherever repeated,
indicate similar or like parts.
The apparatus consists of a casing or cylinder a, which is fitted within a hollow
casting 6, bolted to a bracket c on the standard or pillar d. The hollow casting
is made with two branches 61, 62. Fitted in the branch 6' is a short pipe b³, which
has fitted, on its outer end, a hose pipe connection 64, (shown broken away), leading
to the vacuum storage tank or reservoir. Fitted in the branch b' is a pipe 6, which
has fitted, on its outer end, a hose pipe connection 6, (shown broken away), leading
to the teat cups of the milking machine. Working within the cylinder a, is a
piston e, the piston rod of which passes out through a cap a', screwed on to the
top of the cylinder a. This cap which has air holes a³ in it, is, preferably, screwed
on to a collar a, fitted on the tubular cylinder a. The piston rod f, at its upper
end, passes through a guide bearing f¹, fitted in a bracket f³, cast in one with the
vertical standard or pillar d. Pinned to a stud g¹ on the piston rod f, is a con-
necting rod g, which, at its upper end, is pinned to a stud 9 on a disc-wheel h,
carried on a short horizontal shaft h', which is driven by suitable gearing actuated
either by hand or power, and revolving in bearings, (shown in dotted lines), on the
top of the pillar d. The disc-wheel h has a projecting cam-piece i on it. The
revolutions of the shaft h', and disc or cam-wheel cause the piston rod.or
plunger e to reciprocate up and down within the cylinder a.
The cylinder a has two large openings a, a, cut in it, one at each side, and these
openings communicate respectively with the pipes 6 and 6. Below the holes a³, a',
are, at each side of the cylinder, two vertical series of small holes a (see also
Fig. 3). The casting 6 is made, at each side, with narrow tapering passage ways j
and, leading to and allowing free communication through the series of small
holes a. The object of having the large openings a³ a', and the smaller openings a³, is
to allow the vacuum from the pipe 6, to be gradually cut off or supplied, as the
case may be, to the pipe and teat cups. Instead of having the series of holes a³,
the cylinder may be cut, at each side, with a narrow tapering slot, in the manner
shown at k Fig. 4.
Leading from the pipe 6 is a branch pipe l, which, at its upper end, is connected
to a vacuum reducing valve m, the spindle m³ of which has on it a cup leather
piston m³, which is open to atmospheric pressure on its underside. The weights m'
are attached to the lower end of the spindle m³. The valve, which is of the same

page_text: type as the valve set forth in the Specification of my prior Patent, No. 20,889
of 1891, is so arranged, that, as long as the vacuum within the pipe is above the
minimum vacuum pressure, the suction on the piston m³ is sufficient to pull up the
piston, against the action of the weight, and retain the valve in the open position;
as shown; but, immediately the vacuum reaches the minimum, the weight overcomes
the reduced vacuum, and shuts the valve. As will be readily understood, by
increasing or decreasing the weight m', the minimum vacuum pressure in the teat
cups, and pipe 1, can be raised or lowered, at will. Leading from the valve m is a
pipe n, which has fitted on it a cock o, and carries, at its upper end, an air admission
valve p. This valve may consist of a rubber or other diaphragm p³, having. a
metal collar p³ as a backing, which bears on the knife-edge seat n'. The valve is
fitted at the lower end of a spindle g, which has coiled round it a spiral spring 9'.
is the valve casing and openings in the casing. Air has free admission into
the valve casing, through the openings. is a stay. is a bracket, cast on the
casing r, and on this bracket is fulcrumed, at or about its centre, the lever s, which,
at one end, is pinned to the spindle q, and, on its other end, carries a roller s', which,
by the action of the spring 9', is caused to bear against the surface of the cam
wheel h. The revolutions of the cam wheel h, at certain intervals, through the
action of the cam surface i, presses, down the roller s', and, as a consequence, pulls
up the spindle g, and opens the valve p, against the action of spring 7.
Jointed to the pipe is a pipe connection t, which I term the "junction” pipe,
and which. has fitted on it an automatically acting valve u. This valve may be of
any suitable construction, but is preferably of the same construction as a "Shiels &
Elliot": reducing valve. As will be seen, the arrangement of the valves and valve
seats, are the opposite to those of the valve m. is a small cup leather piston,
open to atmospheric pressure on its underside and fitted on the valve spindle u'.
³ are weights. A bent pipe connects the valve u with the pipe b. This valve,
which acts in the opposite manner to the valve m, is so arranged that the suction
within the pipe t, is sufficient to overcome the weight u³, and keep the valve closed,
so long as the vacuum, within said pipe t, and its connections, is at or above the
minimum, but, whenever the vacuum is reduced below the minimum, the weight
overcomes the suction, opens the valve and supplies vacuum from the pipe v to the
pipe t, until the vacuum again reaches the minimum, when it automatically closes.
According as the minimum vacuum; is altered by the altering of the weights m¹ of
the valve m, so the weights.u must be altered to correspond thereto.
The action of the apparatus.is as follows:-Presuming that the parts are in the
position shown on the drawings, Figs. 1 and 2, and that the maximum vacuum or
suction pressure is acting upon the teat cups, and that there is a free passage along
the pipes 6, 6, 6, 6, to the vacuum storage tank, then, when the shaft h² is turned
towards the left, the connecting rod g and the piston rod f, is forced downwards,
thereby forcing down the long packed-piston e, towards the bottom of the cylinder a,
and gradually cutting off the vacuum from the pipe 6' and teat cups, and reducing
the vacuum at said teat cups to the minimum. When the piston is caused to rise
again, by the continued revolution of the cam wheel h, the vacuum is again
gradually supplied until the piston reaches the top of its stroke, when the maximum
vacuum. is again reached. . In this manner, the piston is caused to reciprocate up
and down, and cause the vacuum pressure to pulsate, i.e. to gradually rise from
the minimum to the maximum pressure, and then gradually fall again.
As the vacuum in the pipe connection leading to the teat cups, falls very
gradually, it is possible, or inay happen, that the vacuum may not fall to the
minimum before the piston or plunger again rises after having completed its down-
ward stroke. To obviate this and to have the pulsations as regular and decided as
possible the valves m, p, are provided.
When the piston e has travelled so far, on its downward stroke, as to just
overlap the lowest holes a³, the cam is, at the same time, just bearing on and
depressing the roller s³, and, as the piston descends, it eventually fully depresses

page_text: said roller, consequently lifting the valve p off its seat and allowing air to gain.
access to the interior of the pipe n, if the cock o is open, and reducing valve m.:
Should the vacuum within the pipe I and teat cups not have fallen down to the
minimum, before the piston e again rises, then the air passes through the valve m."
and reduces the vacuum to the minimum limit when, as before explained the
valve m, automatically closes and cuts off further air ingress so that the minimum
vacuum pressure is maintained at the teat cups until the piston e rises sufficiently
on its upstroke, to again supply: the maximum vacuum to said teat cups.
Should the vacuum at the teat cups, at any time, fall below the minimum from
any cause, then the valve u comes into action, in-the-manner hereinbefore explained,
and automatically supplies sufficient. vacuum from the pipe and storage tank to
make up the deficiency.
As will be seen with this apparatus regular and decided vacuum pulsations are
always insured.
Instead of using the "Shiels and Elliot" reducing valves m and u, the valves
and y shown in section at Figs. 5 and 6 may be employed. These valves consist
of a, preferably, rubber diaphragm w fitted on a spindle w' which works through a
perforated guide plate w. This guide plate, which is screwed on its periphery,
works in the internal screw-thread w³ cut in the valve casing and can be adjusted
by being screwed up or down so as to regulate the tension of the spring w, which,
at one end, bears against the back of the valve, and, at the other end, against the
plate w³. The valve a which may be used in lieu of the valve m is fitted in the
If
reverse manner to the valve y, which may be used in lieu of the valve u.
the valve is used in lieu of the valve m' the action is precisely the same
as said valve except that the diaphragm w is closed on its seat so long as
the air admission valve is closed, but the valve w opens, whenever the air
admission valve p is opened so as to reduce the vacuum in the pipe to the
minimum and when this has been done the action of the spring w* closes the valve
automatically. The spring w' in this case acts in the same manner as the weight m..
Fig. 1 and is of such power as to prevent the valve opening when the vacuum at l
is at or below the minimum.
The valve y when used in lieu of the valve u acts in the same manner as said
valve and automatically opens, against the action of the spring, whenever the.
vacuum within the pipe t falls below the minimum.
The pulsating piston is similar in parts of its construction to the pulsator
described in my prior Specification No. 10259 of 1891.
Although I have shown forms of regulating valves it is to be understood that I
do not confine myself thereto as valves of any suitable and well known construc-
tion may be employed.
When the cock o is shut the air-admission valve is of course in-operative.
The connecting rod g may be made adjustable in its length.
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 :-
1. The general arrangement or combination of parts of the vacuum regulating
apparatus for milking machines, substantially as hereinbefore described and shown
on the drawings annexed.
2. The application and use, in connection with "pulsating" milking machines,
of a valve arrangement for automatically, at certain times, reducing the vacuum
O at the teat cups to the minimum, substantially as hereinbefore set forth.
3. The application and use in connection with "pulsating" milking machines,
of a valve arrangement for automatically supplying vacuum to the teat cups
whenever the vacuum at said cups falls below the minimum, substantially as
hereinbefore set forth.
4. In a vacuum regulating apparatus for milking machines a cylinder or casing a

page_text: having large holes a³, a* and smaller holes a³ or slots k, substantially as and for the
purpose hereinbefore set forth.
5. The combination with the vacuum reducing valve m of an air admission valve
operated synchronously with the reciprocations of the piston e, substantially as
hereinbefore described with reference to the drawings annexed.
Dated this 2nd day of February 1802
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.