Valve Mechanism for Engines.
Year: 1891

page_text: Date of Application, 30th June, 1891-Accepted, 1st July, 1891
COMPLETE SPECIFICATION.
Valve Mechanism for Engines.
We, HARRY BALL, of Stamford, Fairfield County, Connecticut, U.S.A.,
Machinist, and FREDERICK LENGGENHAGER, of Glenbrook, Fairfield County,
Connecticut, U.S.A., Manufacturer, do hereby declare the nature of this inven-
tion, and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Our invention is applicable to direct acting engines generally whether operated
by steam or compressed air and is especially applicable to the type of engines of
which a rock drill is a prominent example. We have therefore illustrated our
invention as applied in connection with a steam actuated rock drill, the object
being to secure rapidity and certainty of operation in all positions in which the
drill can be placed, these points being secured in a simple and economical manner,
all complicated details of construction being avoided.
With this end in view, we have devised the simple and novel construction of
which the following description, in connection with the accompanying drawings, is
a Specification, numerals being used to denote the several parts.
Fig. 1 is a vertical, longitudinal section of the cylinder and steam chest, the
piston being in elevation, the auxiliary piston in section and the automatic slidė
valve in elevation.
Fig. 2, a plan view of the cylinder with the steam chest removed.
Fig. 3, a vertical, transverse section of the cylinder and steam chest on the
linea in Fig. 1 looking toward the left.
Fig. 4, an enlarged, sectional view of the auxiliary piston and automatic slide
valve.
Fig. 5, a section of the auxiliary piston and automatic slide valve on the line y y
in Fig. 4.
Fig. 6, a similar section on the line in Fig. 4 looking toward the left.
Fig. 7, a view corresponding with Fig. 4 and illustrating a modified form of
automatic slide valve; and,
Fig. 8 is a view of the adjusting plate detached.
:
1 denotes the cylinder; 2, the piston; 3, the piston rod; and 4, the steam
chest. The special construction of these parts not being of the essence of our
invention, it is obvious that the details may be varied greatly in practice. 5 denotes
the upper head of the cylinder; and 6, the lower head, said parts being ordinarily
secured together by longitudinal bolts 7 the lower head being provided with the
usual recess to receive a packing 8 held in position by a screw plug 9 through
which the piston rod passes. Upon the top of the cylinder is a flat surface 10
over which the steam chest is placed and secured in place by bolts 11. Within
the steam chest is an auxiliary piston 12, said piston being preferably constructed
substantially as shown in the drawings, the heads of said piston being provided
with recesses 13 and the central portion being entirely open, it being simply
necessary to provide sufficient metal between said heads to connect them together
Within this
rigidly the under side of the steam chest is an opening 14.
opening is a valve 15 having in its under side an opening 16. This valve is adapteil
to reciprocate in opening 14 and to cover steam passages'17 and exhaust passage 18.
Upon the upper side of this valve are wings or projections 19 the purpose of which
will presently be explained, the valve itself engaging between the heads of the
auxiliary piston as is clearly shown in Fig. 1 so that each movement of the
auxiliary piston must carry the valve with it. Steam is taken at a port 20 'and

page_text: exhausted at a port 21, said exhaust port connecting with passage 18 and with an
elongated opening 22 leading into the cylinder. The object of elongating this
opening 22 is to permit the steam to exhaust directly through port 21 during the
last portion of the stroke of the piston in cach direction and also to prevent back
pressure on the piston at the instant the forward movement commences. It will be
apparent from Fig. 1 that the elongation of this opening must relieve the pressure
before the piston for an instant after the forward movement commences in either
direction as the steam is free to pass directly out at the exhaust port. This con-
struction enables us to greatly increase the power exerted by the piston with a
given consumption of steam and also to increase the speed. 23 denotes steam
passages leading from the opposite ends of the steam chest into the cylinder,
passages 17 leading from opening 14 in the under side of the steam chest to the
opposite ends of the cylinder, and passages 23 opening into the cylinder approxi-
mately mid-way between the exhaust opening and the openings of passages 17 into
the cylinder. Opening 16 in the under side of the valve is of sufficient length to
permit perfect communication between one of the steam passages 17 and the
exhaust passage 18 at all times. 24 denotes an automatic slide valve which extends
longitudinally of the auxiliary piston, central openings therefor being made through
the heads as clearly shown in the drawings.
This automatic slide valve is provided with steam passages 25 which admit
steam from the center of the steam chest to recesses 13 (see Fig. 1) to drive the
auxiliary piston forward and which also act to exhaust the steam therefrom into the
center of the steam chest when the auxiliary piston moves in the opposite direction.
The precise construction of this automatic slide valve is not of the essence of our.
invention. It may be made from a solid rod with steam passages grooved out
therefrom as in Figs. 1 and 4 or if preferred it may be made from tubes joined
together by a central plug and plugged at the ends as in Fig. 7. It will be noticed
that the central portion of the steam chest is cored out but that both ends of the
auxiliary piston fit the steam chest closely. In the form illustrated in Figs. 1 and 4
the heads of the auxiliary piston on their inner sides are provided with beveled
recesses 26 which surround the automatic slide valve. At the center of this valve
and in the open central portion of the auxiliary pistor is a sleeve 27 the ends of
which are beveled to engage recesses 26. This sleeve is rigidly locked in position
upon the automatic slide valve by pins 28. The form of automatic_slide valve
illustrated in Fig. 7 consists of tubes the inner ends of which are screwed or riveted
to a central plug 29 and the ends of which are closed by plugs 30. The steam
passages in this form consist of two openings into the tubular portion at each end
of the valve. 31 denotes a friction spring lying in a suitable recess 32 in the
auxiliary piston which bears against the automatic slide valve with just sufficient
friction to hold it in any position in which it may be placed by the action of the
steam. In Fig. 1, the auxiliary piston, valve, and automatic slide valve are all
shown at the extreme of their movement toward the left. In this position of the.
parts steam will pass from the steam chest through the right passage 17 into the
right end of the cylinder to drive the piston toward the left and steam will exhaust
from the left end of the cylinder through the left passage 17 under the valve and
into the exhaust through passage 18. At the opposite extreme of the movement of
the valve steam will pass through the left passage 17 into the left end of the
cylinder and the exhaust will be from the right end of the cylinder through the
right passage 17. The operation of the valve mechanism is as follows: The steam
in the steam chest in the position shown is free to pass through the left steam
passage 25 in the automatic slide valve into the recess 13 in the left. head of the
auxiliary piston. its action being to drive the auxiliary piston toward the right
carrying valve 15 with it but not changing the position of the automatic slide
valve owing to the fact that the steam pressure upon this valve is perfectly
balanced and furthermore that it is retained in position by the spring. As the
movement of the auxiliary piston toward the right continues, however, the left head

page_text: of the auxiliary piston will come in contact with the left end of sleeve 27 and will
force the automatic slide valve toward the right also, the movement of the
automatic slide valve in each direction being checked by suitable stops 33 at
cach end of the steam chest. The movement of the auxiliary piston continues
after the movement of the automatic slide valve has been checked by the stop, as
is shown at the left in Fig. 1. As the auxiliary piston moves in either direction
the steam at the end of the steam chest toward which it is moving exhausts
through the passage 23 into the cylinder until the exhaust is cut off by the auxiliary
piston itself, after which the steam at that end of the steam chest acts as a cushion
and prevents the auxiliary piston from coming forcibly in contact with the end of
the steam chest. The effect of the continued movement of the auxiliary piston
after the movement of the automatic slide valve has been checked is to uncover
steam passage 25 again so that steam from the center of the steam chest can pass
through said passage to the recess 13 in the head of the auxiliary piston to drive it
It
in the opposite direction, these movements being continually repeated in use.
will of course be understood that the beveled recesses 26 in the heads of the
auxiliary piston and the corresponding bevels upon sleeve 27 are not essential
features of construction. We preferably, however, form recesses 26 and bevel the
ends of the sleeve as the valve-like action of these parts assists in preventing the
escape of steam in either direction through the openings in the heads in which
the auxiliary piston slides. When the valve is constructed as in Fig. 7 the result
in use is precisely the same. In this form, supposing the automatic slide valve to
have reached the extreme of its movement toward the left and the movement of the
auxiliary piston to be toward the left, an instant later the auxiliary piston will have
moved far enough so that the right opening at the left end of the automatic slide
valve will be uncovered which will permit the steam to pass through the opening 25
into the recess 13 at the head of the auxiliary piston to drive it in the opposite
direction again.
In order that if found desirable, as for instance in rock drills, steam may be
admitted an instant sooner into one end of the cylinder to drive the piston forward
and the entrance of steam into the opposite end of the cylinder to drive the piston
backward may be slightly retarded, the object being to increase the force of the
blow delivered through the piston rod by the forward movement of the piston and
to lessen the force of the backward movement of the piston, thereby greatly
increasing the effective power when used in a rock drill, we provide an adjusting
plate 34 between the steam chest and the cylinder. This plate is provided with
openings 35 which are adapted to register with steam passages 17 and exhaust
opening 18, as shown in Figs. 1 and 2 or to be moved more or less out of alignment
therewith. We have not shown this last position as it is thought to be too obvious
to require illustration. 36 denotes slots in plate 34 through which bolts 11 pass,
and 37 denotes slots which are at all times in alignment with the parts of steam
passages 23 in the steam chest and cylinder respectively, these slots being made long
enough so that the adjustment of the plate will not affect the movement of steam
through the passages. Suppose that it is desired to increase the force of the
outward movement of the piston and piston rod, that is the movement toward the
right as shown in Fig. 1, relatively to the backward movement thereof, the nuts on
bolts 11 are loosened sufficiently to permit plate 34 to be moved toward the left.
This movement of course carries openings 35 in the adjusting plate further toward
the left which does not affect the passage of steam into the exhaust opening under
the valve, but when the movement of the valve toward the right commences, it
permits steam to enter the left steam passage 17 and pass to the left end of the
piston sooner than when openings 35 are adjusted in alignment with steam
passages 17.
On the other hand, when the piston is at the right end of the
cylinder, the entrance of steam at the right end of the piston to drive it backward
through the left passage 17 will be retarded, owing to the fact that the right side
of said passage is covered by the adjusting plate.

page_text: Having now particularly described' and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :
1. The combination with a steam chest, an auxiliary piston and a valve carried
thereby, of an automatic slide valve lying longitudinally of the auxiliary piston and
provided with steam passages whereby steam is admitted from the center of
the steam chest to the ends thereof to drive the auxiliary piston and the valve.
2. The combination with a steam chest having adjustable stops 33 at its ends,
and an auxiliary piston moving therein said auxiliary piston having recesses 13 in
its heads, of an automatic slide valve lying longitudinally of the auxiliary piston
and provided with steam passages whereby when said automatic slide valve engages
either of the stops, the continued movement of the auxiliary piston will uncover the
steam passages and admit steam to the recesses 13 to drive the auxiliary piston in
the opposite direction.
3. In a mechanism of the class described, the auxiliary piston having heads 12
provided with recesses 13 in their outer ends and beveled recesses 26 in their inner
ends, in combination with an auxiliary piston socketed in the heads and provided
with steam passages through which steam passes to said recesses, and a central
sleeve 27 beveled to engage recesses 26, substantially as described.
4. In a mechanism of the class described, the auxiliary piston having heads 12
provided with recesses 13, in combination with an auxiliary piston socketed in the
heads and provided with steam passages through which steam passes to said
recesses, and a friction spring 31 engaging said automatic slide valve whereby it is
retained in any position in which it is placed.
5. The combination with the steam chest, auxiliary piston and valve 15, of the
cylinder having steam passages 17, and an exhaust passage 18, and the piston, said
exhaust passage having an elongated opening 22 leading into the cylinder so that
steam is permitted to exhaust directly from the cylinder during the last portion of
the stroke in either direction, and back pressure upon the piston is prevented at the
instant the forward movement commences.
6. The cylinder baying steam passages 17 and an exhaust, in combination with a
steam chest, a valve having an opening in its under side adapted to connect one of
the steam passages with the exhaust, and a plate lying under the steam chest and
valve and having openings corresponding with the exhaust opening and steam
passages 17, so that when said plate is moved in either direction steam is admitted
at that end of the cylinder more quickly to drive the piston in the opposite
direction and at the opposite end of the cylinder the admission of steam is retarded,
as and for the purpose set forth.
7. In combination, the cylinder, the steam chest, the valve, steam passages 17
and 23 and the exhaust, and an adjusting plate having openings 35 corresponding
with steam passages 17 and the exhaust opening, said plate being provided with
slots so as to permit adjustment of openings 35 more or less out of alignment with
steam passages 17 and the exhaust.
Dated this 25th day of May 1801
HARRY BALL.
FREDERICK LENGGENHAGER.