Improvements in Thrust-blocks for Screw-propeller and other Purposes.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Thrust-blocks for Screw-propeller and other
Purposes.
I, JOHN PEARCE, of Pendeen, in the County of Cornwall, Merchant, do hereby
declare the nature of this invention to be as follows:-
-
This invention relates to thrust-blocks applicable for use with screw-propeller
shafts and in other situations where a rotating shaft is subjected to considerable
stress in a longitudinal direction.
One
According to one well-known mode of construction, the shaft is carried in
a plummer block bearing formed with a series of transverse grooves, a series
of collars formed on the shaft fitting and working in the several grooves.
side of each groove bearing against one side of the contained collar receives the
thrust exerted by the screw-propeller, or to which the shaft is otherwise sub-
jected, and prevents longitudinal movement thereof.
According to my improved method of construction, I interpose between the
faces of the collars and of. the grooves a series of double coned rollers. These
rollers are mounted upon studs in a ring concentric with the shaft in such a
manner that the one cone surface bears against the face of the collar while the other
cone surface bears against the face of the groove. The cone surfaces may be
set at right angles to the shaft the conicity of the bearing surfaces of the rollers
being such that upon the sides of the latter being produced they meet in a
common centre in the axis of the shaft; the opposed surfaces being immediately
behind one another. The thrust is thus received in a direct line through the cone
surfaces parallel with the shaft.
According to another method of construction the faces of the collars and of
the grooves, instead of being truly radial, are slightly conical, and there is
interposed between each pair of such faces a series of slightly conical rollers, the
conicity of the bearing surfaces and of the rollers being such that upon the
sides of the latter being produced they meet in a common centre in the axis of
the shaft.
In order to counteract the tendency for the rollers to be forced outwards by
reason of the conical form of the bearing surfaces, cach series of rollers is
embraced by a ring provided at suitable intervals with "lathe centres" against
which the outer extremities of the rollers bear centrally, each such ring being
free to rotate with the series of rollers embraced by it.
The inner extremities of the rollers may be similarly mounted on centres
carried by an inner ring.
The centres carried by the outer ring may be rendered capable of adjust-
ment in an inward direction as wear takes place.
Dated this 25th day of September 1899.

page_text: Improvements in Thrust-blocks for Screw-propeller and other
Purposes.
I, JOHN PEARCE, of Pendeen, in the County of Cornwall, Merchant, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:
This invention relates to thrust-blocks applicable for use with screw-propeller
shafts and in other situations where a rotating shaft is subjected to considerable
stress in a longitudinal direction.
According to one well known mode of construction, the shaft is carried in
a plummer-block bearing formed with a series of transverse grooves, a series of
collars formed on the shaft fitting and working in the several grooves. One side
of each groove bears against one side of the contained collar and receives the
thrust exerted by the screw-propeller, or the stress to which the shaft is otherwise
subjected in an axial direction, and prevents longitudinal movement thereof.
According to my improved method of construction, illustrated diagrammatically
in the accompanying drawings, whereof Figs. 1, 2 and 3 are respectively a longi-
tudinal section a transverse section and a plan, I interpose between the faces
of the collars a and of the grooves formed by the thrust-blocks a series of
double coned rollers c c. These rollers are mounted upon studs & in rings e e¹
concentric with the shaft f in such a manner that the one cone surface bears
against the face of the collar a while the other cone surface bears against
the face of the groove. The cone surfaces may be set so as to assume a right-
angle with the axis of the shaft; the opposed cone surfaces c° * being imme-
diately behind one another. The thrust is thus received in a direct line through
these cone surfaces and parallel with the shaft, but at an obtuse angle with the
axis whereon the cones revolve. The conicity of the bearing surfaces of the
rollers may be such that, upon the sides of the latter being produced, they meet
in a common centre in the axis of the shaft.
The ring e is rendered capable of adjustment in an inward direction as wear
takes place by means of plates e².
It will be understood that the conicity of the rollers may be varied as found
desirable and that under certain conditions, instead of rollers having surfaces of
similar conicity, as in the example illustrated, they may be dissimilar as shown
in Fig. 4. According to this method of construction, the surface of the collar a
in contact with the surface c° of the roller is slightly chamfered, thus ensuring
the thrust being received in a direct line through the cone surfaces and parallel
with the shaft. With a view to diminishing any tendency to slip, which might
result from the differences in the speed of movement at the various points of
contact of the surfaces of the cones and of the collar and block, the cone c°
which rolls upon the surface of the collar may be shortened somewhat. It may,
however, be observed that in testing with an arrangement of cones such as shown
in Figs. 1, 2 and 3 the tendency to slip has been found to be inconsiderable.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I claim:-
1. A thrust-block for screw-propeller and other purposes, wherein a number of
double coned rollers are severally mounted about the shaft so that their cone
surfaces roll respectively upon the collar and the block and the thrust is received
in a direct line, through both cone surfaces, parallel with the shaft.

page_text: 2. A thrust-block for screw-propeller and other purposes, wherein a number
of double coned rollers are severally mounted in rings arranged concentrically
with the shaft and between the collar and thrust surface, substantially as herein
described.
3. A thrust-block for screw-propeller and other purposes, constructed or operat-
ing substantially as described with reference to the accompanying drawings.
Toto 01
ו.
2
יז
1000
For the Applicant,
G. G. M. HARDINGHAM,
Chartered Patent Agent, Clun House, Surrey Street, London, W.C.