IMPROVEMENTS IN AIR COMPRESSING AND WATER PUMPS FOR DIVING APPARATUS AND OTHER PURPOSES
Year: 1882

page_text: LETTERS PATENT to John Henry Davis, of Cannon Street, in the City of
London for an Invention of IMPROVEMENTS IN AIR COMPRESSING AND WATER
PUMPS FOR DIVING APPARATUS AND OTHER PURPOSES
PROVISIONAL SPECIFICATION left by the said John Henry Davis at the
Office of the Commissioners of Patents on the 6th October 1882.
JOHN HENRY DAVIS of Cannon Street in the City of London
"IMPROVEMENTS
IN AIR COMPRESSING AND WATER PUMPS FOR DIVING APPARATUS AND OTHER
PURPOSES,"
This invention relates partly to improvements in means for guiding 'the outer
ends of the pump piston rods, whereby extreme simplicity and economy of con-
struction is obtained; and partly to an improved arrangement of the valve boxes
and valves whereby access to the latter is materially facilitated and they can be
easily removed and replaced-.
The improvements which relate to the means of guiding the outer ends of the
pump piston rods consist of the following arrangements. Instead of the piston
rods being prolonged up through cross guide bars and the connecting rods con-
structed with long forks in order to clear the tops of the said prolongations and the
cross guide bars, as is now usually practised, I form with or fix to the upper end of
each piston rod an arm projecting backwards. This arm carries a gun-metal bush
adapted to slide up and down on a guide rod, the lower end of which is secured in
the base plate of the pumps, and the upper end secured in a bar, which I prefer to
arrange so that it may form a stretcher bar between the two A frames carrying the
crank shaft. The connecting rod is formed with a short fork which is pin jointed
to the head of its corresponding piston rod just opposite, or nearly so, to the aforesaid
projecting guide arm. These arrangements are applicable to any number of pumps
placed on the same base plate, there being a separate guide rod for each pump

page_text: piston, but preferably only one stretcher bar to carry the upper ends of all the
guide rods.
The improved arrangement of the valve boxes and valves consists, in so forming
thom, and so arranging the passages therein, that instead of its being necessary to
remove certain parts which are jointed to the outside of the valve boxes, and even
in some cases to remove the pump barrels or the air vessel in order to obtain access
to the valves it is only necessary to remove screw plugs in the bottom of the valve
boxes in order to reach the said valves. The said valves are constructed with seats
screwed into the valve boxes or otherwise secured therein and are so arranged that
they can be withdrawn and replaced through the holes provided for the aforesaid
screw plugs without interfering with or dismounting any other part whatever―

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Davis in the Great Seal Patent Office on the
6th April 1883.
"IMPROVEMENTS
JOHN HENRY DAVIS, of Cannon Street, in the City of London
IN AIR COMPRESSING AND WATER PUMPS FOR DIVING APPARATUS AND OTHER
PURPOSES "
This invention relates, partly to improvements in means for guiding the outer
ends of the pump piston rods, whereby extreme simplicity and economy of con-
struction is obtained, and partly to an improved arrangement of the valve boxes
and valves, whereby access to the latter is materially facilitated, and they can be
easily removed and replaced.
•
In the drawings hereto annexed, Figure 1 is an elevation of a set of pumps
constructed in accordance with the invention, Figure 2 is a cross section of same,
taken on line X X of Figures 1 and 3, and Figure 3 is a plan of the base plate with
part of the pump barrels removed.
The improvements which relate to the means of guiding the outer ends of the
pump piston rods consist of the following arrangements. Instead of the piston-
rods being prolonged up through cross guide bars, and the connecting rods con-
structed with long forks in order to clear the tops of the said prolongations and the
cross guide bars, as is now usually practised, I form with, or fix to the upper end
of each piston rod A, an arm B projecting backwards. This arm carries a gun
metal bush C adapted to slide up and down on a guide rod D, the lower end of
which is secured in the base plate E of the pumps, and the upper end secured in a
bar G, which I prefer to arrange so that it may form a stretcher bar between the
two frames H carrying the crank shaft I. The connecting rod J is formed with a
short fork which is pin-jointed to the head of its corresponding piston rod A just
opposite, or nearly so, to the aforesaid projecting guide arm. These arrangements
are applicable to any number of pumps placed on the same base plate, there being
a separate guide rod D for each pump piston, but preferably only one stretcher bar
to carry the upper ends of all the guide rods.
The improved arrangement of the valve boxes and valves consists in so forming
them, and so arranging the passages therein, that instead of its being necessary to
remove certain parts which are jointed to the outside of the valve boxes, and even
in some cases to remove the pump barrels, or the air vessel, in order to obtain
access to the valves K, L, it is only necessary to remove screw plugs M N in the
bottom of the valve boxes in order to reach the said valves. The said valves are
constructed with seats O P screwed into the valve boxes, or otherwise secured
therein, and are so arranged that they can be withdrawn and replaced through the
holes provided for the aforesaid screw plugs without interfering with or dismounting
any other part whatever. It will be seen from the plan, Figure 3, that the valve
boxes are formed wholly, in the base plate E, that the suction valves L are arranged
to draw from one chamber Q common to all the suction valves, the said chamber Q
being in connection with the general suction pipe R, that the delivery valves K are
each contained in separate chambers S, connected to their respective pump barrels T,
and that the said delivery valves open into a chamber W common to all the delivery
valves and connected with the vessel U.
Having now described the nature of the said invention, and the manner in which
the same is to or may be performed, I would have it understood that what I
claim is
First. In the construction of air compressing and water pumps, the arrangements
for guiding the upper end of the piston rod, consisting of an arm projecting

page_text: from the upper end of the said piston rod, such arm being adapted to slide
on a guide rod, the lower end of which is secured in the base plate, and the
upper end to a bar connecting the crank shaft frames, the connecting rod
being pin-jointed to the upper end of the piston rod by a short fork, tho
whole combined, adapted and operating as herein before described, and
illustrated in Figures 1 and 2 of the drawings.
d. In the construction of air compressing and water pumps, the arrangements
and adaptations of the valve boxes and valves in such manner that access
can be obtained to the said valves and their seatings by means of screw
plugs without interfering with or dismounting any other part whatever, as
herein before described and illustrated in Figures 2 and 3 of the drawings.
In witness whereof, I, the said John Henry Davis, have hereunto set iny:
hand and seal, this fifth day of April, in the year of our Lord, One
thousand eight hundred and eighty-three.