An Improved Method of and Apparatus for Producing and Maintaining a Constant Vacuum in Milking Machines.
Year: 1895

page_text: Date of Application, 1st Oct., 1895-Accepted, 30th Nov.. 1895
COMPLETE SPECIFICATION.
An Improved Method of and Apparatus for Producing and
Maintaining a Constant Vacuum in Milking Machines.
We JERRY EDWARD HARVEY and JOSEPH HEPENSTALL HOOVER, both of
Hubbard in the County of Hardin and State of Iowa, United States of America,
Inventors 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 :-
66
In so-called " vacuum," or "suction," cow-milking machines the effective result
depends upon the intermittent action of a mechanical air-pump, and consequently
the tension of the air, or vacuum," in the milk-receiver constantly varies within
wide limits. It has in fact proved impossible to regulate the operation of the
pump to the degree necessary to maintain an even approximately uniform vacuum,
or "suction," since the inflow of milk into the receiver constantly takes the place of
a larger or smaller volume of the rarefied air, and thus changes the degree of
expansion of the same.
We have devised and put into practical use a method and apparatus by which a
practically uniform "vacuum," or practically uniform expansion and tension of the
air, is automatically maintained in the milk-receiver and its connections, during
the entire milking operation, and that entirely irrespective of the quantity of milk
drawn into the receiver.
Reference is to be had to the accompanying drawings forming part of this
Specification in which
Figure 1 is a vertical central section of the apparatus showing the expansible
air-exhaust chamber partly contracted or collapsed; and
Figure 2 is a similar section, showing the said air chamber fully expanded.
Figures 3 and 4 are sectional views of an expansible telescopic air-exhaust
chamber of modified construction, one view showing it expanded, and the other
contracted, or collapsed.
Figure 5 is a sectional view of another modified form of air-exhaust chamber.
Figure 6 is an exterior perspective view of a third modification or bellows-type,
of the expansible, air-exhaust chamber.
We will first describe the apparatus shown in Figures 1 and 2, with the necessary
detail, and then briefly refer to the several modifications.
The collapsible and expausible air-exhaust chamber, A, and its attachments,
embody the gist of our invention. It is suspended within the oblong, vertical box,
or casing, B, (which might, in a functional sense be a skeleton frame), by means of
The air-chamber
a rod attached to the top of such casing in any suitable manner.
is formed, as to its exterior portion, of two rigid, disc-like heads, a', a², made
preferably of metal, and a collapsible, air-tight, tubular body a³, whose ends are
hermetically secured to such heads. The body, a, is made preferably of rubber,
lined interiorly with canvas to prevent stretching. The upper head, a', is imper-
forate, save that it is provided with an air-outlet valve, a', and the exhaust pipe, aº,
that leads to the milk receiver, C, is rigidly secured to it. The lower head, a², is,
properly speaking, imperforated, but has a tubular downward extension, a', whose
lower end is closed by the weight, D, attached to it as shown.
Interiorly of the air chamber, A, is a series of telescoping tubes a³, arranged
centrally and vertically, and each rigidly attached to a supporting horizontal
diaphragm, a', which is perforated, or skeleton-like, so that air may pass readily

page_text: through it. The edges of the several diaphragms, a', are attached to the inner
sides of the tubular body, a³, of the air-chamber, and thus move up or down with it
as it contracts or expands.
The aforesaid, weight, D, is provided with lateral hooks d, to which are attached,
ropes or cords, d', that run on pulleys, d, at the top of the casing, B, and are
connected with a crank-shaft, d³, journaled and arranged transversely in the lower
portion of the casing B.
The operation of the apparatus is as follows.
Before applying the teat cups to the cow's udder, the vacuum is created by
closing valve, a, in air pipe a, and rotating the crank shaft, d, thus winding up
the ropes, d, and raising the weight, D, whereby the telescoping tubes, -a, are
forced together, the diaphragms, a', and heads, a¹, a², are approximated as closely
as possible, and the tubular body, a³, folded or collapsed, so that the contained air
is expelled through the automatic check-valve, a. The crank, d, is then released,
and the weight, D, allowed to descend and the ropes d', to unwind freely. The
air chamber is thus stretched or expanded, and, there being no air inlet, such
expansion proceeds until the "vacuum," or tension of the air within the chamber,
balances the weight proper, D, and the added weight of the portion of the air-
chamber below the supported upper head, a¹. The parts are thus brought to rest,
say in the expanded position shown in Figure 2. In these
up
and down movements
of the air-chamber proper, it is apparent the telescoping tubes, a³, serve as guides
for the diaphragms or stays, a³, and that the latter prevent entire lateral collapse
of the body, a³, so that it collapses only at points between the diaphragms.
The weight, D, at the lower head of the air-chamber, A, is so proportioned to
other parts, that the degree of " suction," or air tension, in the milk receiver is
exactly that desired and requisite to extract milk from the udder of the cow with
due rapidity. The air chamber, A, being thus held expanded (Figure 2), the
operator opens the stop valve, alo, when the air contained in the pipe, a', the milk
receiver, the teat cups, and tubular connections between the latter and the receiver,
will be drawn into the chamber, A, and a practically uniform degree of rarefaction,
or tension, be produced within the entire apparatus. This access of air to the
chamber will necessarily cause a slight further descent and expansion of the
weighted air-chamber. The milk will at the same time begin to flow and take
the place of a volume of the expanded or rarefied air equal to itself, and this will
obviously allow a further and corresponding descent of the weight, and expansion
of the air-chamber, without however producing any change of air tension, or
"suction." In other words, the weight, D, applies a constant even pull, and
causes a uniform "suction," or vacuum, in the entire apparatus, whatever be the
quantity of rarefied air displaced by the milk drawn from the cow or cows.
the suction or vacuum is perfectly and automatically regulated during the entire
milking operation, whether the air chamber, A, be more or less expanded, up to the
point of maximum expansion of the latter. When the air-chamber has been fully
expanded, the stop valve, al, is again closed, while the weight, D, is being again
raised by the ropes, d', and crank shaft, ds, and during this short time the expansion.
of the air in the pipe, a°, the milk-receiver, and its connections will cause sufficient
"suction to cause continuance of the flow of milk, although with somewhat
reduced rapidity. The valve, a, being then again opened, the operation before
described proceeds anew.
"
Thus
In the modification shown in Figures 3 and 4, the collapsible air-exhaust
chamber, A, is formed solely of rigid, tubular, telescoping sections, whose con-
struction and connection will be readily understood.
In Figure 5, the air chamber, A3, is a cylinder having a sliding piston to whose
rod a weight is attached. The piston rod works in a guide and the piston
constitutes a movable portion of the chamber.
The modification shown in Figure 6 is a bellows, A³, arranged horizontally, and
having a weight, suspended from its lower movable member, or side.
The operation of these several modified forms of vacuum apparatus is obvious,

page_text: 5
and it is also equally clear that the effect produced by each is the same as that or
the preferred form, of which a detailed description has been given, since, in all of
them, the same method of producing a uniform air exhaustion, corresponding
exactly to the volume of rarefied air displaced by the varying quantity of milk
drawn into the apparatus, is carried into practical effect.
It is apparent that, by attaching ropes or cords d', to upper head, a', instead of
to weight, d, and thus holding it in position instead of by rod attached to casing, B,
the air-chamber can be collapsed by lowering upper head, a', (the weight resting on
the ground or other support), until the air-chamber is collapsed as closely as
possible. By winding up the ropes, the air-chamber will be expanded and the air
tension increased until the weight is overcome and lifted off its support, and the
desired degree of air tension produced. By continuing to wind up the rope the
air-chamber with weight attached will be raised to top of casing, B.
The suction does not vary in any appreciable degree, but during the whole
milking operation practically corresponds to the degree of vacuum created when
the milking operation is begun. The displacement of air caused by the inflow of
other words the air-chamber is enlarged
milk is really but a change in the locus;
to correspond to the quantity of rarefied air forced into it by the inflow of milk.
It is obvious that the milk receiver may be within the air-chamber, or that the
air chamber itself may be used as a milk receiver.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. The method hereinbefore described of regulating the air tension or vacuum in
a milking machine, which consists in maintaining during the milking operation, a
constant, practically uniform "suction" in the milk receiver and its connections,
such suction being practically maintained notwithstanding the varying air
displacement caused by the inflow of milk, substantially as specified.
""
2. The method herein before described of regulating the air tension or vacuum in
a milking machine, which consists in varying or adjusting the "suction," or air
tension, in instant and constant correspondence to the inflow of milk into the
receiver, whereby the air tension is kept practically uniform irrespective of such
quantity of milk, as specified.
3. An apparatus for regulating the air tension or vacuum in a milking machine,
which consists of an air-exhaust chamber, having a movable portion and means for
automatically expanding said chamber as the air tension varies in the milk
receiver tubes and air chamber with the inflow of milk, and a suitable tubular
connection between such chamber and the receiver, or teat cups, substantially as
shown and described.
4. An apparatus for regulating the air tension or vacuum in a milking machine,
which consists of an air-exhaust chamber proper, a pendent weight attached to a
movable side or member of such chamber, and a suitable tubular means for
connecting such air chamber with the milk receiver, or teat cups, substantially as
shown and described.
5. An apparatus for regulating the air tension or vacuum in a milking machine,
which consists of an expansible air-exhaust chamber proper, having an air escape
valve, a pendent weight attached to the lower or movable side or member of such
chamber, a milk receiver, a tubular connection between the latter and the air
chamber, and means for raising the aforesaid weight and collapsing the air chamber,
O which means relax and pay out automatically when tension is released, thus allowing
the weight to descend and apply a constant and uniform pull on the movable side
of the air chamber, whereby it is caused to instantly automatically adjust itself to
the change of air tension produced by inflow of milk into the milk receiver, as
specified.
5 6. An apparatus for regulating the air tension or vacuum in a milking machine,
which consists of an expansible air exhaust chamber, having an automatic air-escape

page_text: valve, and its lower side or member being movable, a weight pendent from such
member, a milk receiver, and a tubular connection between the latter and the air
chamber, and ropes and a winding device for raising the aforesaid weight and
movable member of the air chamber, as shown and described.
7. An apparatus for regulating the air tension or vacuum in a milking machine,
composed of an expansible air-exhaust chamber which is suspended at its upper
side from a fixed support and has a flexible, collapsible body, a means for holding
the latter expanded laterally, at one or more points, a weight connected with its
lower end, for applying a constant stretch or tension to said air chamber, and a
tube for connecting the latter with the milk receiver and teat cups as shown and
described.
8. An apparatus for regulating the air tension or vacuum in a milking machine,
composed of an air chamber having an air-escape valve, rigid heads and a flexible
collapsible tubular body which connects the latter, and forms an air-tight enclosure,
a series of rigid perforated diaphragms arranged within the air chamber parallel
to the said heads, a series of telescoping guides connected with the diaphragms,
a weight attached to the lower head, a tube for connecting the air chamber with a
milk receiver and teat cups and means for raising said weight and collapsing the
air chamber as specified.
Dated October 1at 1905
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.