Improvements in and connected with Vacuum Regulating Apparatus for Milking Machines.
Year: 1894

page_text: Date of Application, 31st July, 1594
Complete Specification Left, 30th Apr., 1895-Accepted, 27th July, 1895
PROVISIONAL SPECIFICATION.
Improvements in and connected with 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 certain improvements hereinafter set forth on the
apparatus described in the Specification of my prior Patent for regulating vacuum
in milking machines No. 8325 dated May 3rd 1892.
The first part of the invention relates to improvements on the vacuum pulsating
device and they consist in using a casing which, at its underside, is connected to
and is in communication with the reducing valve or "constant valve" as I prefer
to term it, and, at its upper side, is connected to and is in communication with the
vacuum suction pipe leading to the teat cups of the machine. Fitted in the casing
is a vertical spindle which has on it a disc valve having a, preferably, rubber face.
This face, when the valve is shut, rests on a seat preferably formed in one with the
casing. The top of the casing has a central hole of a, preferably, slightly larger
diameter than the opening or passage way in the valve seat and there is fitted on
the spindle a cup shaped piston which works freely in said hole. This piston has
a curved or rounded back which bears against a diaphragm of rubber or, other
suitable material secured to the top of the casing by means of a dome shaped cover,
or a plate or its equivalent. The top of the casing and also the lower edge of the
dome cover are bevelled internally in order to permit of a free and unrestrained
movement of the diaphragm. The spindle, at its lower end, works in a guide
recess in the bottom of the casing, and, at its upper end, it projects through a
central hole in the cover. Connected to this end is a knuckle joint which is
connected in its turn, to a lever which is bent at one end, and is fulcrumed to a
bracket or jaw cast in one with or attached to the casing or its cover. On the
bent end of the lever is a friction roller or wheel which bears against a cam. which,
for the sake of distinction I term the "pulsator cam," secured at one end of a cam
shaft driven by gearing from the main or fly wheel shaft of the machine. This
"pulsator cam has five throws or movements, caused by gradually increasing its
diameter from the "shut" to the "full open "position: The first or. "shut"
curve occupies about one third of its circumference, the second curve which is one
of a gradually increasing diameter, about one eighth; the third, which is also a
gradually increasing one, about an. eighth; the fourth, which is a uniform one, about
a fourth; and the fifth, which is a gradually decreasing one about one.fifth.
the end of the fifth curve there is an abrupt drop back to the first cunve.
first curve corresponds to the shut position of the pulsating piston, as set forth. in
my prior Specification aforesaid, the second to the uncovering of the small holes or
ports, the third to the uncovering of the large holes or ports and.the fourth to the
full open position, and the fifth corresponds to the down stroke. The arrangement
is practically such, that, as the cam revolves, it acts on the valve in.the casing. and
gradually opens it, thereby gradually supplying vacuum from the storage tank
until the maximum is reached; when, after keeping the valve full open for a short
time, it gradually, though more quickly, clbses it thereby again-reducing the vacuum
until the minimum is reached.
"
Alt
The

page_text: Instead of having this arrangement of pulsator a device may be used which acts
in a substantially similar manner to the pulsator cam and valve and gives practically
the same results. This device consists also of a casing in which a valve works, but
the valve, in this case, consists essentially of two parts, the first part being con-
stituted by a collar or disc on the valve spindle, which, when the valve is
completely closed, rests on a rubber or other seating in the upper side of the valve
proper, said seating being held in place. by an internally bevelled screw ring; and
the second part of a somewhat cup shaped valve provided with a central opening or
passage way and which has, on its under side, a rubber or other face, which, when
the valve is closed, rests on a ring seat secured to the aforesaid casing. The
spindle passes right through the valve and its central opening and an annular
passage way is left between the spindle and the walls of the opening. The top of
this annular passage is normally closed by the collar or disc on the valve spindle
while its lower part is always in communication with the vacuum supply chamber
at the under side of the valve proper. The rubber faces are secured by suitable
rings or nuts. A stop is screwed or fitted on to the lower end of the spindle and
at a certain distance below the lower part or shank of the valve proper. A piston
and diaphragm arrangement similar to that of the pulsating valve hereinbefore
described is fitted at the upper end of the spindle and the whole is raised and
lowered at regular intervals by means of a crank or cam on the driving or other
shaft of the machine. The valve proper is normally held against its seat by the
vacuum suction at its underside.
The arrangement is such that as the spindle rises, it, at first, only lifts the collar
or disc off its seat and opens the annular passage way in the valve proper thereby
allowing a small increase of vacuum to take place at the teat cups, but, as the
spindle continues to rise, it eventually, by means of the stop, lifts up the valve
proper and opens the full passage in the casing thereby increasing the vacuum to
the maximum. When the spindle again descends the valve proper closes first and
the collar or disc subsequently, thereby gradually cutting off the vacuum at the
teat cups. The second part of the invention relates to certain improvements in
the construction of the several valves used in the machine. It has been found in
practice, that, on account of the rebound of the valves as they strike their seats,
the vacuum pulsations are apt to be a little irregular and are liable to fluctuate
slightly. To overcome this I increase the friction preferably at the top of the
spindle by making said spindle with a friction collar which works in a preferably
removable brass liner guide at the top of the valve casing. Around the spindle or
the collar or in the liner is fitted a leather or other ring or cylinder which may be
pressed against the spindle, so as to increase the friction as desired, by means of a
screw or equivalent arrangement adjusted from the outside. The friction
arrangement may be modified to suit different constructions or forms or sizes of
valves.
The weights at the lower end of the spindle instead of being hooked as formerly,
are secured or connected to a stud or bar having a round or ball head which fits
into a removable socket or cup attached to the lower end of the spindle.
The diaphragm has an externally domed cup piston at one side which works in a
bevelled liner secured in the casing.
A dome shaped cover is, preferably fitted on both the top and bottom of each
valve. The bottom cover would, preferably, have an air passage or holo in it.
In order to filter the air, which, at certain times, is allowed to enter the vacuum
destroying valve, I fit on or in connection with it a casing having water therein
and in which a bell, like that of a gasometer, is placed. The bell may sink into
the water or be held up above it. A screen of cotton wool, lint, or a very fine
meshed material may be fitted over the mouth of the hell.
A third feature of the invention relates to the general construction and arrange-
ment of the parts of the apparatus. Under this invention the vacuum destroying
valve, constant valve, bye pass valve for supplying additional vacuum when.
required to the teat cups and the pulsator are all arranged round a pillar which'is

page_text: preferably situated just at the back of the pump or pumps. The pillar carries at
its top the main fly wheel shaft which drives, by means of tooth gearing, a second
or counter shaft situated below it. This counter shaft has on it, at one end, the
cam for operating the air admission valve communicating with the vacuum
destroying valve, and, at the other end, the cam for operating the pulsator. From
one side of the pulsator a branch leads to the constant valve, which is located
beside it, and then to the storage tank. The bye pass valve is located in front of
the constant valve and has branches communicating, on the one hand, with the
storage tank, and, on the other hand, with the pulsator or the pipe leading to the
teat cups therefrom. This arrangement makes the machine compact and also
effects a saving in the cost of construction. The several valves may be carried on
lugs or brackets cast on or secured to the pillar.
H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent.
Improvements in and connected with 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 improvements on the "Shiels & Elliot" milking
machine and specially to certain improvements hereinafter set forth on the apparatus
described in the Specification of my prior Patent for regulating vacuum in milking
machines No. 8325 dated May 3rd 1892.
Aud in order that my said invention may be properly understood I have hereunto
appended five explanatory sheets of drawings, whereon,
Fig. 1 is a front elevation of a milking machine having my improvements applied
thereto.
Fig. 2 is an elevation of one side of the machine and Fig. 3 is an elevation of the
other side.
Fig. 4 is a plan of the machine.
Fig. 5 is a vertical section of the "pulsator."
Fig. 6 is a vertical section of a modified form of the pulsator.
Fig. 7 is a vertical section of the "bye pass" valve.
Fig. 8 is a vertical section of the "vacuum destroying valve."
Figs. 9, 10, 11 and 12 show in section, arrangements for producing friction on the
spindle 80.
Fig. 13 is a view of the pulsator cam.
Referring to the drawings whereon the same reference numerals wherever
repeated indicate the same or similar parts:-
The apparatus as a whole consists, as shown at Figs. 1 to 4, of a platform or
foundation 1 to which two vertical cast iron pillars 2, 2, are secured. Fitted on
the foundation and between these pillars is an exhaust or vacuum pump 3 of any
ordinary or suitable construction. The pump communicates by a pipe connection 4
"valve 7,
with a closed vacuum storage tank 5 and by a pipe 6 with the "bye pass"
pipe 7, and pulsator valve 8.
The " constant valve 9 is also connected by the branch pipe 10 with the pipe
on the one hand and by the branch pipe 11 with the pulsator valve 8 on the other
hand.
The pipes 13, 14, lead from the pulsator 8 to the milk pail and the teat cups of

page_text: the machine. A branch pipe 19 connects the pipe 13 with the valve 20 and the
small air admission valve 21 connected to said valve 20 by the pipe 22 (Fig. 2).
The whole of these valves and their connections are arranged around and supported
by one of the pillars 2 as shown.
Carried in bearings 23, 23, on the top of the pillars, 2, 2, is a crank shaft 24 to the
crank of which the piston rod 25 of the pump piston is connected. On the outer
end of the shaft 24 is a fly wheel 26.
The crank shaft may be driven by power or by hand.
On the opposite end of the shaft 24 to the fly wheel 26 is a toothed wheel 27
which gears with an intermediate toothed wheel 28 and this latter wheel 28 in its
turn gears with the toothed wheel 29. The wheel 28 is carried on a stud 30 fitted
in a link 31 connected loosely at the ends, respectively to the shaft 24 and the short
cross shaft 32, which latter passes right through the pillar 2 and carries at one end
the cam wheel 33 with its can piece 34 and at the other end the cam wheel 35 with
its cam piece 36. The shaft 32 is driven by the wheel 29, which is keyed to it.
The cam wheel 33 as it revolves, gives, at intervals, a downward pressure, by
means of the cam piece 34, to the roller 38, at one end of a lever 37 which is
fulcrumed at 39 to a supporting bracket 40 cast in one with the casing 21ª of the
valve 21. The other end of the lever 37 is connected by a link to the rod 41 of the
valve 21. The arrangement is such that every time the roller 38 is depressed by
the cam 34 the valve 21 is lifted up off its seat against the action of spring 21 and
communication is opened with the pipe 22 and valve 20.
The other cam wheel 35 with its tapered cam 36, once during each revolution
gradually depresses the roller 42 at one of a bent lever 43 fulcrumed on a jaw or
bracket 44 carried by the pulsator valve 8. The other short end of the lever 43 is
connected by a link with the spindle 45 (see also Fig. 5) of the pulsator, which,.
constitutes a feature of the invention and which I will now proceed to describe.
Referring to the sectional view Fig. 5 it will be seen that the pulsator consists of
a casing in which there are three passage ways 46, 47, 48, which communicate
respectively with the pipes 13, 14, and the teat cups, the pipe 11 and the "constant
valve 9, and the pipe 7 leading to the "bye pass" valve 7.
"
Fitted in the casing is the vertical spindle 45 having on it a disc valve 50 with a
rubber face 51. This face, when the valve is shut, closes down on a ring seat 52
formed in the casing. A hole 53 of slightly larger diameter than the passage way
in the valve seat 52 is made in the top of the casing and in this hole 53 a cup shaped
piston 54, fitted on the spindle 45, works freely. The curved or rounded back of
the piston bears against a rubber or other diaphragm 55 secured to and held in
place in the top of the casing by means of a domie shaped cover 56 bolted to the
casing. The top of the casing and also the lower edge of the dome cover are
bevelled internally in order to permit of a free and unrestrained movement of the
diaphragm. The spindle 45, at its lower end, works in a guide recess 57 and at its
upper end it projects through a central hole in the cover 56. Connected to this
end is a link 58, which, in its turn, is connected to the bent lever 43 fulcrumed to
the jaw 44. At the end of the lever is the screw 62 provided with the roller 42
which, as before stated, is, at certain times, depressed by the action of the cam 36.
59 is a passage way by means of which atmospheric air gains access to the bank of
the diaphragin 55. The pressure of the air on the diaphragm 55, which is larger in
area than the valve 50 tends to keep the latter closed. The "pulsator" cam
wheel 35, 36, has five throws or movements caused by gradually increasing its
diameter, as shown at Figs. 3 and 13 from the point a to the point b. The first
curve occupies about one third of the circumference of the wheels; the second
-curve d, which is one of a gradually increasing diameter, about one sixth; the third
curve e, which is also a gradually increasing one, about a sixth; the fourth curve f,
which is a uniform one, about one sixth; and the fifth curve.g which is a gradually
decreasing one, about one fifth. At the end of the fifth ourze at b, there is.tan
abrupt drop back to the first curve c. The first curve c corresponds to the shut
position of the pulsating piston, as set forth in my prior Specification No. 8825/92

page_text: aforesaid, the second d to the uncovering of the small holes or ports, the third e to
the uncovering of the large holes or ports and the fourth to the full open position ;
the fifth g to a certain extent corresponds to the down stroke.
The arrangement is such that when the first part c of the wheel 35 is bearing on
the roller 42, the valve 50, 51, remains shut down on its seat 52, but, when the
part d bears on the roller 42 it is slightly depressed, and, as a consequence, the
valve is lifted up slightly off its seat so as to permit a slight increase of suction or
vacuum to take place in the pipe 13 and to act on the teat cups.
When the part e
presses on the roller it is still further depressed and as a consequence the valve is
opened still further. When the part f presses on the roller it opens the valve to its
full extent so as to allow the maximum of vacuum or suction to act on the teat cups.
When, however, the part g acts on the roiler the valve is allowed to gradually
close itself, by the action of the air pressure on the back of the diaphragm 55, until
the roller reaches the point b when the valve suddenly closes and remains closed
until the point a is again reached. In this manner, as the cam 35 revolves, the
valve 50 is gradually opened to supply vacuum from the storage tank 5 until the
maximum vacuum is reached, when, after remaining full open for a short time, it is
at first gradually and then suddenly closed again so as to reduce the vacuum to the
ninimum. The vacuum is thus caused to "pulsate" i.e., to rise from the minimum
to the maximum and then fall again to the minimum.
The vacuum is never
allowed to fall below the minimum by the action of the "bye pass "valve 7 which
comes into operation when the valve 50 of the pulsator closes.
Instead of having this construction of "pulsator" a device can be used as shown
at Fig. 6 which acts iu a similar manner to the pulsator cam and valve and gives
practically the same results. This device consists also of a casing 8 in which a
valve 50 works, but the valve, in this case, consists essentially of two parts the first
part being constituted by a collar or disc 63 on the valve spindle 45, which, when
the valve is completely closed rests on a rubber or other seating 65 on the upper
side of the valve proper 50, said seating being held in place by an internally
bevelled screw ring 64; and the second part of the somewhat cup shaped valve 50
provided with a central opening or passage way 70 and which has, on its under
side, a rubber face 67 which, when the valve is closed, rests on a ring seat 68
secured in the casing 8. The rubber 67 is held in place by ring 69. The spindle 45
passes right through the valve 50 and its central opening and the annular passage
way 70 is left between the spindle and the walls of the opening. The top of this annular
passage is normally closed by the collar or disc 63 while its lower part is always in
communication with the vacuum supply chamber 71 and pipe 11 by means of the
hole 66. A stop 72 is screwed or fitted on to the lower end of the spindle. A
piston and diaphragm arrangement 54, 55, similar to that of the pulsating valve
Fig. 5 is fitted at the upper end of the spindle and the whole is raised and lowered
at regular intervals by means of a simple cam on the driving shaft 24 of the
machine which, at certain times, depresses a roller, such as 42 Fig. 5, on the
lever 75 and raises the spindle 45. The valve 50 is normally held against its seat
by the vacuum suction at its underside.
The arrangement is such that, as the spindle 45 rises, it, at first, only lifts the
collar 63 off its seat and opens the annular passage way 70 in the valve 50 thereby
allowing a small increase of vacuum to take place in the passage 13 and at the teat
cups, but, as the spindle 45 continues to rise it eventually by means of the stop 72
lifts up the valve 50 and opens fully the passage 68 thereby increasing the vacuum
to the maximum. When the spindle 45 again descends the valve 50 closes first
and the collar 63 subsequently, thereby gradually cutting off the vacuum at the
teat cups.
"
"
The "bye pass
valve 7 and the " constant valve are of the construction
shown at Fig. 7 the.ouly difference between them being that the valve 9 is more
heavily weighted than the valve 7. Vacuum is automatically.supplied during the
operation of the machine from the storage tank 5 through the valve 9 at a constant
and regular power of suction whilst the valve 7 only opens .and.allows wacuum to

page_text: pass to the pulsator 8 and teat cups whenever the vacuum at said teat cups from
any cause, is reduced below the proper minimum.
As will be seen at Fig. 7 the valve 7 or 9 consists of a casing 77 which com-
municates on the one hand by the passage 78 with the pulsator 8, and on the other
hand by the passage 79 with the vacuum supply pipe 6. The vertical spindle 80
has on it a valve 81 with a rubber face 82 which closes against the under side of
the ring seat 83 in the central passage way of the casing and it is also connected
to a diaphragm 84 and an externally domed cup piston 85 working in the bevelled
ring or liner 86. The domed bottom 77 which is bolted to the casing holds the
diaphragm 84, which is open, through the hɔle 59, to atmospheric pressure on its
underside, in place. The weight 87 is attached to the lower end of the spindle 80
by a ball and socket joint 88. The weight 87° of the valve 9 is larger than the
weight 87 of the valve 7 see Figs. 1 to 4. A guide pin 80ª working in a groove 80°
prevents the spindle 80 turning round. dare nuts. d' is a stop nut.
The valve 20, Fig. 8, only differs from the valves 7 and 9 in that its valve 81ª
(faced with rubber 82*) closes down on the upper end of the ring seat 83°. It has
a flat top 89. Its weight 90 is secured to the spindle by a ball and socket joint 88°.
The valve communicates on the one hand, by the passage 91 with the pipes 19 and 13,
and, on the other hand by the passage 92 with the pipe 22 and valve 21.
The weight 87° on the valve 9 is just large enough to overcome the suction in
the passage 78 and retain the valve constantly open so as to keep up a regular
maximum supply of vacuum to the pulsator 8 whilst the weight 87 on the valve 7
is not large enough to keep the valve open against the suction on its upper side,
unless the suction at the teat cups from any cause decreases below the desired
minimum when it opens and supplies increased vacuum until the minimum is again
reached. In the case of the valve 20 however the weight 90 is so arranged that
as long as the vacuum in the passage 91 and pipes 19, 13, and teat cups is above
the desired minimum the suction on the upper side of the valve 81, 82º, is sufficient
to overcome the action of the weight and keep the valve open, but immediately the
vacuum reaches the minimum the weight 91) overcomes the reduced vacuum and
automatically shuts the valve. The size of the different weights 87, 87, and 90
are so proportioned to the work to be performed and to each other that the vacuum
at the teat cups is always properly controlled.
It has been found, in practice, that on account of the rebound of the valves as
they strike their seats, the vacuum pulsations are apt to be a little irregular and
are liable to fluctuate slightly. To overcome this 1 increase the friction preferably
at the top of the spindle by making said spindle with a friction collar 67 which
works in a removable brass liner guide 93 at the top of the valve casing. This
arrangement is also shown fitted on the spindles of the pulsators Figs. 5 and 6.
Instead of using the above-mentioned arrangement I may use the friction devices
shown in Figs. 9, 10, 11, and 12. In Fig. 9 the spindle 80 has a cap 94 screwed
on it and between this cap and the liner 93 a spiral spring 95 is fitted and held in
place by a disc 96 secured to the cap by a screw 97. 98 is a cover. By tightening
the screw 97 the spring 95 can be bulged out so as to increase the friction against
the liner 93. In Fig. 10 the top of the spindle 80 is split and a screw 99 with a
tapered head is inserted just above the split so that by tightening up the screw the
tapered head can be made to force the split parts outwards and thereby increase
the friction against the liner 93. In Figs. 11 and 12 which are respectively
vertical and horizontal sections, the upper end of the spindle 80 has attached to it
two semi-circular pieces 100, 101, which are pressed against the wall of the liner 93
by the bow springs 102. The pressure can be increased by means of the taper
headed screw 99, which can be screwed up so as to press outwards the two semi-
circular pieces 104, 105, to which the springs 102 are secured by means of the
pins 103 which latter also retain the pieces 100, 101, in place.
Under this invention it will be seen that the vacuum destroying valve 20, constant
valve 9, bye pass valve 7, for supplying additional vacuum to the teat cups and the
pulsator 8 are all arranged around the pillar 2 which is situated just at the side of

page_text: the pump or pumps 3. This arrangement makes the machine compact and also
effects a saving in the cost of construction. The several valves as shown are
carried on lugs or brackets cast on the pillar.
The action of the apparatus is as follows :—
The crank shaft being set in motion the pump 3 is operated and a strong vacuum-
is produced in the reservoir 5. When the vacuum has reached its proper limit in-
the reservoir (indicated by a gauge not shown) the "constant" valve 9 opens
automatically and supplies vacuum to the "pulsator" 8. The teat cups of the
milking machine are now fitted on the cow's teats. The movement of the shaft 24
also operates by means of the gearing 27, 28, 29, the secondary shaft 32 and causes
the cam wheels 33, 35, to revolve and the cam 36 on the wheel 35, as the latter
revolves, gradually forces down the roller 42 (see also Fig. 5) and opens the
valve 50 thereby allowing vacuum to pass (if I may use the expression) from the
pipe 11 to the pipes 13, 14, and teat cups and produce a suction on the cow's teats.
As the valve 50 is gradually opened by the action of the cam 36, on the roller 42,
the suction at the teat cups gradually increases until at length, when the roller 42
has reached the point h of the cam, it attains the maximum. Shortly thereafter when
the roller reaches the point b of the cam it is suddenly cut off by the closing of the
valve 50.
As the sudden closure of the valve 50 would cut off all the vacuum from
the teat cups and they would, as a consequence, fall off the cow's teats it is necessary
to provide means whereby sufficient minimum vacuum will be supplied to them at
such times. The "bye pass "valve 7 is used for this purpose and it is so arranged
that immediately the vacuum in the pipes 13 and 14, from any cause, falls or tends
to fall below the minimum about necessary to retain the cups on the cow's teats, it,
under the action of the weight 87, opens automatically and supplies sufficient
vacuum to make up any deficiency. When, however, by the action of the cam 36
the pulsator 8 is again caused to supply vacuum to the pipes 13, 14, and teat cups,
the valve 7, owing to the increased suction in the passage 78 (Fig. 7), overcoming the
weight 87 automatically closes until the pulsator 8 again closes when the valve 7
automatically opens again. In this manner the valve 7 is made to supplement the
action of the pulsator 8 and prevent the vacuum at the teat cups at any time and
from any cause falling sufficiently low to allow the teat cups to drop off the cow's
teats. When the roller 42 of the pulsator 8 has reached the end of the cam 36
and is just descending to the point b so as to suddenly close the valve 50 and cut
off the vacuum, the roller 38 (Fig. 2) is just at the point i of the cam 34 and is just
being depressed by said cam so as to open the valve 21 against the action of the
spring 21 and allow air to pass down the pipe 22 to the passage 92 of the valve 20
and so long as the roller is travelling along the cam 34 which corresponds in length
to the part e of the cam wheel 35, said valve 21 is kept open and air has free access
to the passage 92. Now should the vacuum in the passage 91 of the valve 20 and
at the teat cups not have fallen to the minimum the excess of vacuum at once
overcomes the weight 90 and opens the valve 82ª thereby admitting air to said
passage and teat cups so as to reduce the vacuum to the minimum limit, when, as
before explained, the valve 82 again automatically closes and cuts off further air
ingress so that the minimum vacuum is maintained until the cam 36 again acts on
the pulsator 8 and supplies the maximum vacuum.
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 consider
novel and desire to claim is :-
1. The general arrangement and combination of parts of the apparatus
substantially as hereinbefore described and shown on the drawings annexed.
2. In milking machines a "pulsator" constructed and operating substantially as
herein before described with reference to Fig. 5 of the annexed drawings.
3. In milking machines a pulsator constructed and operating substantially as
hereinbefore described with reference to Fig. 6 of the drawings annexed.
4. In combination, the main shaft (24), the secondary shaft (32) driven by

page_text: gearing from the main shaft, the cams 33 and 35 on the secondary shaft, and the
air admission valve and pulsator valve operated by said cams, substantially as
herein before described and shown on the drawings annexed.
"
5. The improved construction of ". constant valve; "bye pass" valve, and
"vacuum destroying" valve, substantially as hereinbefore described with reference
to Figs. 7 and 8 of the drawings annexed.
Dated this 29th day of April 1895.
· H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent.