Improvements in Cross-head Blocks for Engines.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Cross-head Blocks for Engines.
I, NATHANIEL LOMBARD, of No. 1053 Saratoga Street, Boston, County of
Suffolk, State of Massachusetts, United States of America, Mechanic, 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 :-
This invention relates to improvements in cross-head blocks for engines, either
stationary, portable, or marine. Ordinarily this part of the engine has sliding
reciprocating movement between parallel and straight guides, said cross-head being
provided at its end with cross-head blocks rigidly affixed thereto.
My invention consists in pivotally mounting the cross-head blocks, which are to
be segmental in shape, so that the required stroke or movement of the cross-head
is obtained by oscillation of the cross-head blocks upon the fixed parallel guides,
and in providing the oscillating blocks and their parallel guides with teeth, so as
to prevent the displacement of the former relative to the latter. In this manner all
sliding friction in this part of the structure is obviated. Further details of adjust-
ment and construction will be hereinafter described.
The drawings represent, in
Fig. 1, a side elevation of a vertical engine in part and embodying my invention.
Fig. 2 is a front view of the same.
Fig. 3 is a detail view of the cross-head block, side elevation.
Fig. 4 is a section of the same on line in Fig. 3.
In the accompanying drawings, 2 represents the crank, 3 the connecting-rod,
4 the cross-head, and 5 the piston-rod, of a steam engine, all which are of the usual
type of construction.
At 66 are shown the parallel guides, between which the cross-head moves. This
piece is forked, as shown in Fig. 2, and is bored to receive the cross-head pin 7, by
which the connecting-rod 3 is secured thereto, the latter being bifurcated at this
end and adapted to straddle the cross-head. (See Fig. 2.)
To support the cross-head between the guides 6 6 and to obviate the friction
created by the sliding movement of the cross-head blocks upon the guides as
ordinarily occurs, I have shown such blocks 88 as curved or segmental pieces,
composed as follows: A semi-circular hub 9 in the present instance is formed to
fit partially about the connecting-pin. From this hub projects a stud 10, circular
or otherwise in cross-section to enter lengthwise the lower end of an arm 12, which
at its opposite end terminates in a flanged curved foot or plate 13. A transverse
holding-bolt 14 extends through the stud and arm, while an adjusting screw 15 is
further provided, whereby accurate adjustment for wear or play can readily be
compensated. These cross-head blocks, identical in construction, are mounted upon
the cross-head pin 7 with the curved plates 13 bearing against the faces of the
guides. Thus as the piston-rod moves and actuates the cross-head such a distance
as is required for the length of stroke the cross-head blocks merely rock, while
the distance covered by such oscillation from one extreme to the other is equivalent
to the length of stroke. In this way it is evident that all sliding friction is
removed- -in small engines a result of much importance. Further these cross-head
blocks are easily adjusted, little or no wear occurs, and they are readily applied to
engines of every make at a very small outlay.
To secure the cross-head blocks and compel them to maintain fixed relative
positions with respect to the parallel guides, and thereby obviate any tendency to
slip, I have formed a series of teeth 16 upon the sides of said guides, while a similar
series 17 are created upon or attached to the edge of each block. These

page_text: teeth project beyond the parts to which they are attached, so as to interlock and
yet bring the centre of pitch in a plane coincident with the bearing-surfaces of
the guides and blocks. It is evident that no strain or thrust is caused by this
construction, since the curved plates rock freely and easily upon the guides, the
sole function of said teeth being, as before stated, to prevent slip or displacement
of the cross-head blocks as they oscillate upon the guides. Other mechanical
arrangements than the two series of teeth may be used to effect equivalent results.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. In combination with a cross-head, and its parallel guides, the cross-head
blocks, pivotally secured to the cross-head, and terminating in curved plates which
interlock with and rock upon the said guides, substantially as and for purposes
described.
2. In an engine, a cross-head, its parallel guides, the piston and connecting-rod
combined with the cross-head blocks oscillating upon the guides, and their adjusting
mechanism, substantially as specified.
3. In combination with a piston rod, the parallel guides, a cross-head and its
pivotal pin 7, the oscillating cross-head blocks, each composed of the hub 9, its
stud 10, the arm 12, and the curved extremity or foot 13, adjustably united, sub-
stantially as herein stated.
Dated this Twelfth day of May 1891
NATHANIEL LOMBARD.