Improvements in the Construction of Friction Clutches.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Construction of Friction Clutches.
We, FREDERICK LISTER CROFT and Toм ARTHUR PERKINS, of the Great
Northern Works, Leeds Road, Bradford, in the County of York, Millwrights, do
hereby declare the nature of this invention to be as follows:
This invention has for its object, the construction of the driving boxes of
friction couplings or clutches used for transmitting rotary motion from one shaft
to another, by so arranging the said driving boxes that, the whole or the
greater portion of the circumference of the same, when expanded, is brought into
contact with the internal circumference with what is termed the shell of the
box, thereby obtaining a greater frictional contact or gripping surface between
the driving box and the shell, than is the case with driving boxes as hitherto
constructed.
The shell of the box is
We accomplish our object in the following manner.
prepared with an internal boss, upon which is mounted the sleeve of the driving
box which is split in one position through the sleeve, and in one or more positions
through the circumference of the box to be expanded into contact with the internal
circumference of the shell of the box.
The expansion may be accomplished by right and left hand threaded screws
operated by levers having suitable connections with a sliding sleeve mounted on
the shaft; on the operation of the sleeve, the screws are turned and the circum-
ference of the driving box expanded or withdrawn as desired.
By providing the driving box with a sliding sleeve and mounting the same in
the manner described, the box is always kept in its proper relationship to the
circumference of the shell of the box, and by splitting the sleeve, the divided
circumference is allowed to expand more readily, and retain a truer curve for
contact with the internal circumference of the shell of the box, than is the case
when the boxes are constructed in the manner as hitherto.
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We, FREDERICK LISTER CROFT and TOM ARTHUR PERKINS, of the Great
Northern Works, Leeds Road, Bradford, in the County of York, Millwrights, do
hereby declare the nature of this invention and in what manner the same is to be
[Price 8d.1

page_text: performed, to be particularly described and ascertained in and by the following
statement:-
This invention has for its object, the construction of the driving boxes of
friction couplings or clutches used for transmitting rotary motion from one shaft
to another, by so arranging the said driving box expansion rings that, the whole
or a greater portion of the circumference of the same, when expanded, is brought
into contact with the internal circumference of what is termed the outer shell
of the clutch or coupling, thereby obtaining a greater frictional contact or gripping
surface beween the driving box ring and the outer shell of the clutch or coupling,
than is the case with driving boxes arranged as hitherto constructed.
.1
In describing our invention in detail, reference is made to the accompanying
sheets of drawings in which Fig. 1 represents an elevation of a friction clutch
made according to our invention shown 'partly in section, with the connections
to the sliding sleeve all mounted on the respective shafts.
Fig. 2 is a front view of the clutch shown partly in section, with the cover
plate removed for more clearly showing the interior of the clutch.
Fig. 3 is a front elevation of an enlarged detached detail of the driving, box
expansion ring.
Fig. 4 is a section of the same through the line a. b.
Fig. 5 is a front elevation of an enlarged detached. detail of a modified form of
the driving box expansion ring, and
IN
Fig. 6 is a section of the same through line c. d.
In all the figures like letters indicate like parts where they appear..
In carrying out our invention, the outer shell portion A. of the friction clutch
and the driving box B. are accured on the respective shafts C. and C. in the
ordinary manner, as is also the sliding sleeve D. and on the boss of the driving
box B. is mounted a driving box expansion ring F. which is split or divided
in the centre as at G, see Fig. 4, in a manner so as to allow the said ring to be
expanded into contact with the internal circumference of the outer shell portion A.
of the friction clutch.
This expansion ring F. is bored in the centre at H. concentric with the circum-
ference to fit the boss of the driving box B. and the circumference and web are
divided to the centre hole H. as at J. J, the division or opening J. separating
the expansion ring the entire width of the circumference and a portion of the
centre boss as far as the centre slit G, this portion of the centre boss being
intact for the remainder of the circumference of same, a section of which is shown
at H in Fig. 4. The opposite division or opening J. separates the expansion
ring from the circumference and a portion of the centre boss, as far as the centre
slit G, the remainder of this portion of the boss being intact for the remainder
of the circumference, a section of which is shown at H2. in Fig. 4; thus by.
dividing the boss in the centre by slit G. and separating the expansion ring from
the circumference to and through the front and back sections of the centre boss
in the manner described, the sectional boss allows the ring to be expanded into
contact with the internal circumference of the outer shell A...
The driving box B. is provided with blocks B¹. and B². which engage with the
recesses B. and B. of the expansion ring F.
The expansion of the ring F. may be accomplished by right and left hand
threaded screws L. and L. upon the centre portion L2. of each of which, is
mounted a lever M. serrated at each side of the boss at M¹. These levers when
adjusted are secured in position by serrated collars N. mounted upon square or
other suitable shaped portions of the bars, and are held in contact with the
bosses M. by the threaded nuts P. screwed against the outer surface of each
collar N, the levers being coupled to the sliding sleeve D. by adjustable links R.
so that by operating the sliding sleeve in either direction, the screws L. and L¹.
are rotated and the ring F. expanded or contracted as required.
Our invention may be carried into effect by constructing the driving box

page_text: expansion ring F. in a manner as shown by detached details Figs. 5 and 6.
According to this arrangement there is no slit G. through the centre boss, and only
one opening from the circumference of the expansion ring to and through the
centre boss at J, the other opening J. through the circumference joining with
the spaces or recesses 133. and B.
The expansion ring F. when arranged in this manner is operated by right and
left and threaded screws L. and L. mounted and actuated in the manner as
hereinbefore described.
By arranging the expansion rings of the driving boxes in the manner described,
when expanded, a truer curve of the circumference is retained and the entire
circumference of the ring brought into contact with the internal circumference
of the outer shell A. of the clutch, thereby gaining an efficiency of contact
combined with strength not hitherto attained by expansion rings as hitherto
constructed.
When used as a coupling for connecting two shafts, the outer shell A. of the
clutch is recessed, and by preference bushed at S. and into this bush a boss of
the driving box is inserted, so that the said box and outer shell A. retain their
proper central relationship to each other.
It will be obvious to persons acquainted with the construction of friction clutches,
that our improved arrangement of driving box expansion rings may be used,
with such friction clutches as are applicable to pullies, wheel gear, winding
drums and the like, and may be expanded as hereinbefore described or by other
suitable methods.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is:-
1. A friction clutch with which is combined the expansion ring F. of a driving
box, the centre boss of such ring being divided by a slit G. and the circum-
ference of the ring and portions of the centre boss divided and arranged substan-
tially in the manner and for the purpose as herein before set forth.
2. An expansion ring divided by a central slit G. and through the circum-
ference and portions of the centre boss substantially in the manner as herein-
before described and illustrated by the drawings.
3. An expansion ring having a division J. on one side extending from the
circumference to and through the centre boss, and on the opposite side of the
expansion ring an opening through the circumference only, all the parts being
arranged and constructed substantially in the manner and for the purpose as
hereinbefore set forth.
1001