IMPROVEMENTS IN AUTOMATIC VALVES AND VALVE GEAR FOR OPERATING AND REGULATING THE STROKE OF HYDRAULIC MACHINES
Year: 1884

page_text: I, JOHN FIELDING, of the Atlas Works Gloucester, in the county of Gloucester
Engineer, do hereby declare the nature of, my invention for "IMPROVEMENTS IN
AUTOMATIC VALVES AND VALVE GEAR FOR OPERATING AND REGULATING THE
STROKE OF HYDRAULIC MACHINES," to be as follows:-
This invention relates to the valves and valve gear of hydraulic machines for
Punching, Shearing, rivetting and such like operations or for working pumps by
hydraulic pressure and consists of two rams working in their valve boxes, and
provided with suitable cup packings some of which act to control the inlet and
outlet of the actuating fluid one of the rams is connected to the main hydraulic
ram of machine and being constantly subject to the working pressure it serves to
effect the return stroke of the main ram. The second valve ram has two diameters
the smaller being constantly under pressure, the larger alternately open to pressure
and exhaust, the alternative being effected by the movement of the first valve ram.
The second ram is thus caused-to reciprocate within the valve box and thereby to
control the flow of working fluid to and from the main cylinder. In order to
regulate the stroke of such machines I connect the first valve ram and the main
ram of machine to the opposite ends of a slotted lever, an adjustable fulcrum is
provided, upon which a block, fitting in the slotted lever, is pivotted. When the
fulcrum is midway between the ends of the lever the strokes of the main and valve
ram are equal, but if it be moved nearer the main ram the stroke of the latter
becomes less than that of the valve ram, an opposite effect is caused by placing the
fulcrum block nearer to the valve ram the stroke of the latter however remains of
constant length that of the main ram only being affected. In order to accomodate
the motion of the punch or other tool to suit various thicknesses of plates it is
necessary not only to vary the power and length of stroke but it is necessary to
adjust the tool so that when working at its minimum stroke, it approaches to the
bolster or die and when working its maximum stroke to approach less nearly.
This is effected by suitably arranging a fixed slotted or grooved bar by the side
of the slot in valve lever, this fixed bar carries the fulcrum stud upon which the
block in the valve lever slot works. The fixed bar is inclined in relation to the
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page_text: valve lever in such a manner that the stud, as it approaches the end attached to
the main ram, is lowered, the result being that when the main ram is working its
shortest stroke, it is also working near its lowest position and the punching or
other tool is working nearest to the opposite or corresponding tool or bolster, The
position of the fulcrum in the slots may be adjusted by means of a screw or its
equivalent.
It is usually advantageous in punching and such like machines to cause the
operating tool to perform its forward and return stroke quickly and with little or
no dwell at the end of the forward stroke, but with a considerable pause at the end
of the return stroke to allow time for the adjustment of the work. In rivetting
machines it is however advantageous for the tool to pause at both ends of its
stroke. For this purpose I provide means for regulating the amount of opening in
the ports leading to and from the larger diameter of second valve ram, so that the
latter is caused to move slowly or rapidly as may be desired the duration of the
pauses may be regulated to any degree.
Dated this Seventh day of February 1884.

page_text: I, JOHN FIELDING of the Atlas Works Gloucester, in the County of Gloucester
Engineer do hereby declare the nature of my invention for "IMPROVEMENTS IN
AUTOMATIC VALVES AND VALVE GEAR FOR OPERATING HYDRAULIC MACHINES" 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 the valves and valve gear of hydraulic machines for
Punching, shearing, rivetting and such like operations or for working pumps by
hydraulic pressure, and consists of two rams working in their valve boxes, and
provided with suitable cup packings, some of which act to control the inlet and
outlet of the actuating fluid one of the rams is connected to the main hydraulic
ram of machine and being constantly subject to the working pressure it serves to
effect the return stroke of the main ram. The second valve ram has two diameters
the smaller being constantly under pressure, the larger alternately open to pressure
and exhaust the alternation being effected by the movement of the first valve ram.
The second ram is thus caused to reciprocate within the valve box and thereby to
control the flow of working fluid to and from the main cylinder. In order to
regulate the stroke of such machines I connect the first valve ram and the main
ram of machine to the opposite ends of a slotted lever, an adjustable fulcrum is
provided upon which a block fitting in the slotted lever is pivotted. When the
fulcrum is midway between the ends of the lever the strokes of the main and valve
rams are equal, but if the fulcrum be moved nearer the main ram the stroke of the
latter becomes less than that of the valve ram, an opposite effect is caused by
placing the fulcrum block nearer to the valve ram the stroke of the latter however
remains of constant length that of the main ram only being affected.
In order to
accomodate the motion of the punch or other tool to suit various thicknesses of
plate it is necessary not only to vary the length of stroke but it is necessary to
adjust the tool so that when working at its minimum stroke, it approaches more
nearly the bolster or die and when working its maximum stroke to approach less
nearly.
This is effected by suitably arranging a fixed slotted or groved bar by the side
of the slotted valve lever, this fixed bar carries the fulcrum stud upon which the
block in the valve lever slot works. The fixed bar is inclined in relation to the
valve lever in such a manner that the stud as it approaches the end attached to
the main ram, is lowered the result being that when the main ram is working its
shortest stroke, it is also working near its lowest position and the punching or
other tool is working nearest to the opposite or corresponding tool or bolster.
The position of the fulcrum in the slots may be adjusted by means of a screw or
its equivalent.
It is usually advantageous in punching and such like machines to cause the
operating tool to perform its forward and return stroke quickly and with little or
no dwell at the end of the forward stroke, but making a considerable pause at the
end of the return stroke to allow time for the adjustment of the work. In rivetting
machines it is however advantageous for the tool to pause at both ends of its
stroke. For this purpose I provide means for regulating the amount of opening in
the ports leading to and from the larger diameter of second valve ram, so that the
latter is caused to move slowly or rapidly as may be desired the duration of the
pauses may be regulated to any degree.

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1. Shews a section of the valve body, rams, bushes and cup packings, and an
elevation of the working levers and adjusting gear.
Fig 2. Shews to a smaller scale the application of the valve and gear to the
cylinder and slide of a punching machine."
In Figure 1. A is the valve body, B is the valve plunger which controls the flow of
fluid to and from the main cylinder of machine, b is a loose bush in which B works.
B' is an enlarged piston which operates valve B, C is the valve plunger which
'controlls the flow of fluid to and from the chamber B. C is a loose bush in
which works. C¹ is the ram or plunger which is connected to and receives
motion from the main ram of machine, B³ is the pressure or inlet cup packing
and B' the exhaust packing in connection with the passage to main cylinder
C and C are similar packings in connection with the passage to chamber B³
D is an adjusting plug for the purpose of regulating the escape of water from the
chamber B³ or for altogether preventing its escape. E is the pressure inlet pipe
F the outlet pipe and G the branch leading to the main cylinder H is also an
outlet pipe preferably connected to main outlet pipe F. I is the slotted lever
.connecting the ram C¹ to the main slide of machine by means of links II' J is a
block fitting within the slotted lever and working upon a pin formed upon another
block K which is arranged to slide in a fixed slotted bracket L by means of a
.screw M. Similar letters in Figure 2 refer to corresponding parts as lettered in
Figure 1. In Figure 2 N is the main frame of machine O the cylinder and slide
shewn in dotted lines and P is the main ram. Qis a stud screwed into main slide
, for attaching the link E².
Referring to the foregoing description of Figure 1 and 2 the mode of operation
is as follows.
The various parts being in the position shewn in Figures 1 and 2 the fluid enters
by the pipe E and bush b into chamber g and thence by pipe G to main cylinder it
also enters by passage i into bush or chamber its pressure being exerted against
the end of the ram C. The main slide then commences its downward stroke
and by means of the lever I and links I¹ I causes valve ram C¹ to ascend, the
latter very soon closing the outlet from chamber B₁ shortly before the termination
of the stroke the cup packing on ram C passes over the annular port in bush c and
adınits pressure to chamber B³ The area of B¹ being greater than that of B, the
valve ram B, B' is pushed by the fluid pressure towards 6 until the solid part of B
comes inside the cup packing B³ and the packing B' has passed the lower annular
port in chamber G, the fluid in main cylinder is thus free to escape the annular
space between valve stem and the bush 6¹ and the branch F. The pressure acting
upon the end of ram C effects its reverse movement and that of main slide.
. Shortly after the commencement of the return stroke the valve ram C closos the
communication between the pressure bush cand the chamber B' and immediately
before the end of this stroke, the ram C₁ working through the cup packing C³
opens B2 to the escape pipe H, and the pressure acting upon the end of ram B
returns the latter to the position shewn in drawing, This completes the cycle of
⚫ operations:
Referring now to the adjusting gear when the block K is in position shewn
. Figure 1 and 2. the movement of the lever I is shewn by the dotted lines R R. If
- however the block K be placed at opposite end of slot in brackets L the movement
of lever I will be represented by the dotted lines R R. The movement of the main
slide being correspondingly modified.
If the screw plug valve D be closed. The valve B will be prevented from
admitting pressure to the main cylinder and the slide will therefore remain
stationery at the top of its stroke thus leaving the punch or other tool clear of the
work. The valve D may be arranged to be opened and closed either by hand or
foot power.

page_text: The bracket L may be graduated and marked to indicate the proper position of
block K for various thicknesses of plate, or length of stroke.
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;
1st The employment of a ram as shewn at C, C¹, Fig 1. serving the double
purpose of a return ram and a distributing valve, substantially as and for the
purposes herein set forth and described.
2nd The combination of valve box A. rams C, C³, B. B¹; as shewn in Fig 1
substantially as described.
3rd The combination of lever I, blocks J. K, bracket L and screw M as shewn in
Fig 1 substantially as and for the purposes herein set forth and described.
4th The employment of a valve as D. Fig 1 substantially as and for the purposes
herein set forth and described.
•