and similar Adjustable Levers.
Year: 1886

page_text: and similar Adjustable Levers.
I, HERBERT JOHN ALLISON, of the firm of Allison Brothers, of 52 Chancery Lane,
London, in the County of Middlesex, Patent Agents, do hereby declare the nature of
this invention, which has been communicated to me from abroad by George Patten
Whittlesey, Patent Solicitor, and Daniel Pratt Wright, Engineer, both of Washington,
in the District of Columbia, United States of America, 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 latch or locking device for retaining in any desired
position the reversing lever or throttle lever of a steam engine. It is applicable to
any steam engine, either stationary, marine, or locomotive, but is especially adapted
to the latter, as shown in the accompanying drawing.
In engines with the link motion, the travel of the valve and point of cut-off is
usually regulated by the reverse lever, which, as commonly constructed, is movable
backward and forward between two notched quadrants. A spring bolt or latch on
the lever engages with any desired notch, and locks the lever in the position to
give a certain cut-off. When the engineer wishes to admit steam into the cylinder
during a longer portion of the stroke, he lifts the latch and moves the lever
toward the end of the quadrant, until the latch can be dropped into the next
notch.
In locomotives, the quadrant is usually provided with eight notches for the
forward, and as many more for the backward eccentric. As a certain amount of
material must be left between the notches for the sake of strength, it is found to
be impracticable to get a very fine adjustment of the cut-off where it is most
desirable.
Various expedients have been proposed for overcoming this difficulty, such as
worm gears, screws, secondary levers, and the like, for the purpose of moving the

page_text: reverse lever a short distance forward or backward after it has been locked in the
notch nearest to the point desired. But so far as I am aware, all of these devices
require two separate and independent operations by the engineer; that is to say, he
must first bring the reverse lever to one of the notches and lock it there, and then
manipulate another device to accomplish the further adjustment of the cut-off.
The purpose of this invention is to enable a comparatively fine adjustment to be
obtained by a locking mechanism which requires only the ordinary manipulation of
the reverse lever to operate it.
To this end this invention consists in an auxiliary locking mechanism located
adjacent or contiguous to the latch or other lock with which the reverse lever is
provided.
This invention further consists in certain combinations and arrangements of
parts which will be particularly pointed out in the claims.
In the accompanying drawings, forming part of this specification, and in which
like letters indicate like parts in all the views,
Fig. 1 is a side elevation of a reversing lever and its quadrant, showing the
improved lock.
Figs. 2 and 3 are perspective views of the main and auxiliary latches.
Figs. 4, 5 and 6 are sectional views showing the operation of the latches.
The reverse lever, A, the quadrant B, with its notches b, b, the reach rod, latch
handle D, links E, E, and pin F, are of the usual construction.
The main latch, H, which is clearly shown in Fig. 3, has a slot, a, through which
passes the pin F, and a slot, h, which receives the shank of the bolt G, by which
the latch is guided in its up and down movement. The latch, H, is normally
forced downward by a spiral spring, K, encircling the rod L, the lower end of which
rests in a socket in the upper end of the latch. The other end of the rod is sup-
ported and guided by an aperture in the lug, M, on lever A. The latch may be
lifted in the ordinary way by the handle D, and links E, E.
With a single latch, the lever A, must be moved the entire distance from one
notch to the next whenever it is necessary to change its position. But as an inter-
mediate position would often answer quite as well, and in many cases better, owing
to the nicer adaptation of the cut-off to the work demanded of the engine,
I provide an auxiliary locking device, which is operated by the same handle that
controls the main latch or lock. This consists, preferably, of one or more auxiliary
latches, I.
The drawing shows one such latch, which, as seen in Fig. 2, has a slot c, to
receive the shank of bolt G, a slot, d, to embrace the lug e on the main latch H,
and two ears f. f, each provided with a slot g, g, for the pin F. The auxiliary
latch slides upon the face of the main latch, and they are preferably formed
with the intermatching lugs and slots as above described, though these are not
essential.
The slots, a, g, are preferably made equal in length to the depth of a notch in
the quadrant plus the diameter of pin F. The auxiliary latch is provided with a
spring, K, and rod, L', similar to the main latch.
The operation of the auxiliary latch is clearly illustrated in Figs. 4, 5 and 6.
Fig. 4 shows both latches raised, the slots a and g registering with each other, and
the pin F at the top of the slots.
Fig. 5 shows the main latch dropped into a notch, the auxiliary latch remaining
in the position in which it is shown in Fig. 4, while the pin F has descended with
latch and rests at the bottom of slots g, g.
Fig. 6 shows the lever moved from the position shown in Fig. 5 a distance equal
to the width of one notch, the main latch bearing on top of the quadrant as in
Fig. 4, the auxiliary latch engaging with the notch, and the pin F resting at the
bottom of slot a.
It thus appears that the handle D must be released in order that either latch
may engage with a notch, while the slot in the idle latch allows the pin F to
descend with the engaging latch.

page_text: It is evident that if one auxiliary latch is used, it renders the lever capable of
double the number of adjustments that it commonly has; two auxiliary latches
will give three positions of the lever for each notch in the quadrant, and so on.
The latches may be placed side by side, but I prefer to arrange them one in
front of the other, as shown, in order that each may enter the notches in both
quadrants.
The practical value of the improvement appears in the great saving of fuel
which follows from the more careful adapting of the cut-off to the work to be
done. Furthermore, the auxiliary latch or latches are actuated and controlled by
the ordinary latch handle D, thus relieving the mind of the engineer from attending
to an extra fitting; a very material advantage over those contrivances which
require the adjustment to be made by means of a second lever, a screw, or
the like.
It is also evident that this improvement is applicable not only to reversing
levers but to throttle levers, wagon brake handles, and in fact to any lever which
is locked by a latch or lock engaging with a notched bar.
י
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 :-
1. The combination with a lever and its quadrant, of a main locking mechanism,
and an auxiliary locking mechanism operated by the same handle that controls the
main locking mechanism, substantially as and for the purpose described.
2. The combination with a lever and its notched quadrant, of a latch to lock
the lever in a position corresponding to any one of said notches, and an auxiliary
locking device to lock the lever in intermediate positions, said auxiliary locking
device being operated by the same handle that controls the latch, substantially as
and for the purpose set forth.
3. The combination with a lever and its notched quadrant, of a main latch and
one or more auxiliary latches, all operated by the same handle, substantially as and
for the purpose described.
4. The combination with a lever and its notched quadrant, of two or more
latches, all operated by the same handle, the notches and latches being so arranged
that only one latch is in engagement with the quadrant at the same time, substan-
tially as and for the purpose set forth.
5. The combination with lever A, and quadrant B, having notches b, b, of
handle D, links E, E, pin F and latches H, I, having slots a, g, said slots being.
equal in length to the depth of a notch plus the diameter of pin F, substantially
as and for the purpose set forth.
6. The combination of lever A, quadrant B, having notches b, b, handle D,
links E, E, pin F, bolt G, main latch H, having slots a, h, and lug e and auxiliary
latch I, having lugs f, f, and slots c, d and g, substantially as and for the purpose
set forth.
7. The combination of lever A, having lug M, quadrant B, having notches b, b,
handle D, links E, E, pin F, bolt G, latches H and I, rods K, K', and springs L, L³,
substantially as and for the purpose set forth.