Year: 1898

page_text: I, ERNST GUSTAV HOFFMANN, of 43, Beech Street, Barbican, London, Mechani-
cal Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to clutches brakes and 'like mechanical devices in which
the displacement of one member must be effected from time to time such dis-
placement being of limited extent but effected with considerable force as for
example in the case of a clutch in which the loose or moveable clutch member
must be forced under considerable pressure against the other clutch member.
In accordance with this invention I provide one or more loose bodies preferably
balls which are forced with a wedge like action between the bodily moveable
member of the device or a sleeve of same and an abutment the movement of the
several bodies being preferably effected by the longitudinal movement of an outer
sleeve with the interior of which the balls or the like are in contact the several
parts being so arranged that the final effective movement of the moveable
member of the clutch or other device is made with great force.
The sleeve last mentioned acts to force the balls inward between the abutment and
the moveable member or its sleeve and is preferably provided with an incline for
better acting upon the balls.
The balls. when covered by the sleeve are effectively locked as is also the move-
able member but to provide a further locking means, a tapering increase may be
made in the internal diameter of the sleeve rearward of the incline to enable the
balls to have a slight radial expansion, when the sleeve is finally pushed home.
In one form of the invention the moveable member may be operated in one
direction by a spring to put it out of engagement with the other clutch member
but as an alternative the sleeve operating the balls may be extended and pro-
vided with a shoulder which is adapted to come in contact with a ball or balls
carried in a recess in a part of the moveable member such balls forming an
obstacle to the withdrawal of the sleeve and causing same during such with-
drawal to bring with it the moveable member of the clutch. The sleeve may be
provided with an opening closed by a plug such opening serving for the purpose
of withdrawing or inserting any or all of the balls above mentioned.
The opening between the fixed abutment and the moveable member above
described is preferably a flaring one. Means are provided for obtaining an adjust-
ment between the moveable and the other member of the clutch.
Dated the 11th day of February 1898.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, W.C.,
Chartered Patent Agent,
For the Applicant.

page_text: .
Improved Means for Actuating Clutches, Brakes, and the like.
I, ERNST GUSTAV HOFFMANN, formerly of 43, Beech Street, Barbican, London,
but now of Hamlet House, Chelmsford, Essex, Mechanical Engineer, 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 improved means for actuating clutches, brakes and
other mechanical devices of like general nature in which the displacement of one
member of the device must be effected from time to time, such displacement
being of limited extent but effected with considerable force as for example in
the case of a clutch, in which the loose or movable clutch member must be forced
under considerable pressure against the other clutch member. Various means
have been devised hitherto for effecting the required movement of such a member
with the necessary force, but so far as I am aware, such means have not proved
to be efficient and reliable under all conditions of use or they are complicated
and therefore both cumbersome and expensive as well as liable to get out of
order. Moreover they generally have projecting parts which are highly objec-
tionable when such devices are applied to rapidly rotating shafts or wheels. It
is therefore the object of my invention to produce a device of this general char-
acter which shall be exceedingly simple in construction, very compact and free
from projecting parts, and which, moreover, shall act with great force, shall be
capable of application for many different purposes in substantially the same
general form, and shall be certain in operation under all conditions of use. In
accordance with my invention I provide one or more loose bodies, preferably
balls, which are forced with a wedge like action between the bodily-movable
member of the device and an abutment, the movement of the several bodies being
preferably effected by the longitudinal movement of a sleeve with the periphery
of which they are in contact; the several parts are so disposed and formed with
relation to one another that the final, effective movement of the movable member
of the clutch or other device is made with great force. It is obvious that my
invention can be carried out in many different constructions as well as applied to
many different uses, but in order to enable the nature and mode of operation of
my invention to be fully understood, I will describe the same hereinafter with
reference to its embodiments in the construction chosen for illustration in the
accompanying drawing, in which :-
:―
Fig. 1 is a longitudinal central section of a clutch applied to a pulley on a
counter-shaft and embodying my invention the clutch being represented as
closed.
Fig. 2 is a similar view with the clutch open.
Fig. 3 is a longitudinal central section of a double clutch applied to two
pulleys one part being open and the other closed and
Fig. 4 is a similar view shewing both parts open.
In the construction shewn in Figs. 1 and 2 the shaft A carries a pulley B
forming the female member or a part to be locked or checked loosely mounted
in this case upon a ball bearing B₁ of some approved construction such bearing
being carried by a boss C locked upon the shaft by a set screw or in some other.
suitable way. The other parts of the device are represented as mounted upon a
sleeve D which is held to the shaft by a set screw but this is merely for the
purpose of enabling all of the parts to be removed and replaced together it being
obvious that they might be supported directly upon the shaft. The sleeve D is

page_text: screwed to the boss C at C¹ which constitutes an adjustment between the part B
and the male member of the clutch.
This male member E is represented as held to the sleeve D to rotate therewith
but with freedom to move longitudinally thereon by a key e engaging with a
longitudinal groove in a boss f. This boss has an annular groove in which seat a
row of balls f sunk about one half of their diameter in said groove. Around the
boss is a sleeve I having a shoulder I¹ at its end adapted to abut against the
row of balls which thus form an obstacle to the withdrawal of the sleeve and
forms a means for positively connecting said sleeve to the boss f and male
member of the clutch whereby the latter can be withdrawn and the clutch opened.
The sleeve I is provided with an opening closed by a screw plug or cap I2
through which opening the balls f¹ may be inserted and withdrawn their with-
drawal enabling the sleeve I to be entirely removed for withdrawal of the male
member E.
The sleeve D is provided with a rigid abutment F and carries a sleeve, ring,
or abutment G though this may be formed in one with the abutment F if desired.
This ring has a bevelled face and between it and a further ring G¹ is located a
series of balls H which may also be reached through the opening in the sleeve I
for renewals in certain positions of such sleeve. The opposing faces of the
rings G G¹ form a flared opening and though only one is shewn as inclined which
is the preferred form both may be so if desired.
It will be seen that the balls H have a wedge-like action and that as they are
forced in between the ring G and the ring G₁ which abuts against the moveable
portion of the device the latter will be moved with great force in the required
direction and that as soon as the pressure on said balls is removed they may be
readily forced out to allow the clutch to be opened.
For the purpose of effecting the movement of the balls H the sleeve I is
grooved circumferentially at 13 for engagement by a suitable actuating lever and
is preferably provided for contact with said balls with an inclined or cam sur-
face adapted to force the balls inward while it is preferred also to make a slight.
tapering increase in the internal diameter of the sleeve I at the back of this
point as shewn at the point forming the corner of the surface i being thus the
point of smallest diameter within the sleeve which increases backwardly at i
The operation of the device will be readily understood. When the clutch is
to be opened the sleeve I is withdrawn and the shoulder I¹ abutting against the
obstacle balls f¹ draws the part E away from the part B all the parts being then
in the position shewn in Fig. 2 the balls H being in their cutward positions both
by reason of the inclination of the face of the ring G and by reason of centri-
fugal action.
To close the clutch the sleeve I is shifted and in its movement its surface i
forces the balls between the rings or abutments G G¹ with the result that the
moveable part E is driven forward and engages with the other member B as
shewn in Fig. 1.
During the last of the movement of the sleeve I the movement of the balls H
in a plane transverse to the axis of the device is very slight and hence the final
movement of the member E takes place with great force and the sleeve I being
now over the balls H they are held in position so that all the parts are perfectly
locked the lever or the like operating in the groove of sleeve I having no further
pressure to exert after it has effected the closing of the clutch, no backward pres-
sure from which will have any effect in opening it.
When the rearward tapering increase beyond the lower point of the surface i
is employed it has the effect after the sleeve has forced the balls over the point of
allowing them to expand slightly in a radial direction and in so doing they tend
to push the sleeve I still further in the direction from left to right until it comes
to a stop which may be on various points but in the drawing shewn would be
when the top point of the surface i abutted against the ring G¹.

page_text: This arrangement necessitates somewhat greater power to open the clutch but it
provides means of applying an increased force to close it and a supplemental self-
closing or locking device in case of vibration which might tend to move the
sleeve backwards or where wear may have caused the parts to 'lose their accuracy"
of fit.
When it is desired to be able to open the clutch' easily a plain surface is given
to the sleeve I behind the lower point of surface i..
In Figs. 3 and 4 in place of the obstacle balls f¹ and the shoulder on sleeve I
the combination of which will effect the opening of the clutch, a spring g is
employed between the clutch member E and the boss C.
These figures shew the combination of two friction pulleys which is very often
employed in counter shafting and in this arrangement it is not possible to employ
the obstacle balls so that the springs are employed in place thereof. Such
springs however may be employed in place of the obstacle balls in the arrange
ment shewn in the preceding figures.
In this case there is only one central sleeve D on which are mounted the 'parts
composing the right and left hand clutches said sleeve being fixed on the shaft
by one or more set screws in the central collar or abutment F which can be got
at by an opening in the part I.
The sleeve I is practically the same as 'in Figures 1 and 2 only it is 'double
ended, two sleeves being formed in one and two openings are formed therein
closed by screw plugs or caps I for the purpose of inserting and removing the
balls. It will be obvious that the invention may be enibodied in many other
constructions than that described so that the invention "is not limited to the
particular fornis shewn.
.j
i
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 movable member and an abutment, of one or more.
movable bodies or balls and means to force said bodies radially between said
abutment and said movable member and by enclosing said balls to hold them
in place whereby the device is self locking substantially as and 'for the purpose
described.
2. The combination with a movable member and an abutment,, one of the
opposing faces of said parts being inclined of one or more movable bodies, or balls,
and means to force said bodies radially between said abutment and said movable
member and by enclosing said balls to hold them in place whereby the device is
self-locking substantially as and for the purpose set forth.
3. The combination with a movable member and an abutment, of one or more
movable bodies or balls and a sleeve movable longitudinally, in contact with said.
bodies to force them between said abutment and said 'movable member to lock the
latter substantially as and for the purpose set forth.
1
...
4. The combination with a movable member and an abutment, of one or more
movable bodies or balls and a sleeve, movable longitudinally and having an
inclined or cam surface for contact with said bodies to force them between said
abutment and said movable member to lock the latter substantially as and for the
purpose set forth.
.
.i
5. The combination with a movable member and an abutment, of one or more
movable bodies and a sleeve movable longitudinally in contact with said bodies
to force them between said "abutment and said movable member to lock, the latter
said sleeve having a hole to permit the removal and insertion of said bodies and
having a plug to close said hole, substantially as and for the purpose set forth.
6. The combination with the longitudinally movable clutch member the
movable clutch member and an abutinent of one or more movable bodies and a
sleeve longitudinally movable in contact with said bodies to 'force them between

page_text: said abutment and said movable member substantially as and for the purpose, set
forth.
onl
7. The combination with a shaft, a clutch member mounted on said
said
shaft, a sleeve also mounted
shaft, and the second clutch
member mounted on said sleeve, of an abutment fixed oll said sleeve,
one or more movable bodies and means to force said bodies between said
abutment and said movable member, to lock the latter substantially as and for
the purpose set forth.
8. The combination with a movable member and an abutment of one or more
movable balls and a sleeve movable longitudinally and having an inclined or
cam surface for contact with said bodies to force them between said abutment
and said movable member and a tapering increase in the internal diameter of the
sleeve rearward of the inclined surface to permit of a slight radial expansion of
the balls substantially as and for the purpose set forth.
9. The combination with a movable member and an abutment, of one or more
movable bodies or balls, a sleeve movable longitudinally in contact with said
bodies to force them between said abutment and said movable member to lock
the latter a shoulder on the sleeve and a ball or balls carried by the movable
member and adapted to form an obstacle to the removal of the sleeve and serve
as a means for withdrawing the movable member substantially as set forth.
ated this 10th day of Novemba 1000
PHILIP M. JUSTICE,
55 & 50, Chancery Lane, London, W.C.,
Chartered Patent Agent,
For the Applicant.
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, W.C.,
Chartered Patent Agent,
For the Applicant.