A Combined Claw and Friction Clutch.
Year: 1889

page_text: Date of Application, 30th Sept., 1889
Complete Specification Left, 14th June, 1890-Accepted, 19th July, 1890
PROVISIONAL SPECIFICATION.
A Combined Claw and Friction Clutch.
PETER VALENTINE MCMAHON of The Electric Lighting Depôt Bolton Street Water-
ford in the County of Waterford Ireland Electrical Engineer do hereby declare the
nature of, this invention to be as follows:-
My invention consists of an improved clutch suitable for pullies or line of shafting.
My improvement consists in novel construction and arrangement of parts, my
object being to overcome the difficulty arising from engaging a shaft in motion to a
pulley at rest or a continuation of the same line of shafting at rest, or vice versa."
In carrying out my invention I use a special form of claw clutch, made by pro-
longing the distance between the bottom of the claws and the groove, this being the
bearing of part of the friction clutch to be hereinafter described. The other part of
the claw clutch to have a projection at an acute angle to the shaft on each of the
claws, or there may be a greater or less number of claws than projections; the pro-
jections I prefer to line with hard wood, to increase the co-efficient of friction, and
form part of the friction clutch, the back may be produced to form a sleeve to which
the pulley can be keyed, or may have two or more lugs, to which can be bolted an
existing pulley.
On the first mentioned part of the claw clutch a ring is feathered with a groove at
one end to take the striking in and' out gear, the other end is cone shaped, to bear
against the projections on the claws of the claw clutch, this forms the friction
clutch.
Both friction and claw. parts have striking in and out of gear arrangements. To
start the pulley or line of shafting at rest, the friction clutch is put into action, this
brings the pulley or line of shafting up to the speed of the driving part. Then the
claws are engaged without any jar or shock to pulley or shaft.
In case the claw lever should be engaged first by mistake, the claws would most
likely be broken off. To guard against this, I make one lever lock the other, so that
the friction lever must first be pulled into position before the claw lever can be
unlocked, or struck into gear.
Dated this 28th day of September 1889.
..COMPLETE SPECIFICATION.
A Combined Claw and Friction Clutch.
I PETER VALENTINE MCMAHON of The Electric Lighting. Depot Waterford in the
County of Waterford Ireland, Electrical Engineer 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 :-
My invention consists in a combination of "Claw and Friction Clutch" to accom-
plish which combination, a prolonged form of claw clutch is used, and on each claw,
projections are cast so as to form extensions, these projections being at a suitable
acute angle to the axis of the clutch; thereby producing part of a conical shaped
surface.
. There may be more or less projections than claws, or if preferable the projections
may take the form of a complete cone shaped ring, cast upon or fixed to the claws
in any manner that commends itself. The projections whether separate or continuous,
are lined with hard wood; or other suitable material, this is to increase the co-efficient
of friction between the projections of the loose part of the clutch, or the part to be
[Price 8d

page_text: -
driven, and the conical ring; which is feathered on the other, or second part of the
ordinary claw clutch, here-in-after to be more fully described.
The second part of the ordinary claw clutch; has the distance between the bottom
of the claws and the groove prolonged, to form a bearing for the aforesaid conical
ring, this part is feathered to the shaft, to allow a lateral motion for the purpose of
engaging, as in an ordinary claw clutch. The first and second mentioned parts;
form the common claw clutch; modified to suit the combination.
The conical ring is feathered on the second part of the claw clutch, and when
pressed against the projections of the first part of the claw clutch gets it up to
speed. This forms the friction part of the clutch.
The drawings appended illustrate my invention and its applications, the same
letters and figures apply to all views:
Figs. 1. shows a half elevation and cross section through the line A B.
: Fig. 2. shows a half elevation and section along the centre of the shaft, the claw
clutch shown out of gear, and the friction part getting up speed.
Fig. 3 is an end elevation of the locking arrangement for the levers.
Fig. 4 shows the combined claw and friction clutch, arranged for joining up two
lines of shafting, the part C G. forms a bearing for the other part of the shaft, but
may have a larger bearing than that shown if necessary. The part C G in this case
is keyed to its own half of the shaft.
In Figs. 1 and 2. the parts C G. & F., with the projections H. H. H. removed,
and without the collar D. form the e mmon claw clutch.
I use projections H. H. H. three in this case, cast on the claws G. of the common
claw clutch, these projections H. H. H. are lined with hard wood I or other suitable
material, held in position by screws; (not shown in the drawing) or otherwise, and
inclined at an acute angle to the axis of the shaft.
In cases where a large frictional surface is necessary, the projections may take
the form of a continuous ring; similarly lined with hard wood; or other suitable
material.
The part C G. forms a bushing for the loose pulley or other article 'to be driven,
and is loose on the shaft, it may also form the pulley boss in which case all would be cast
in one piece, or it may be keyed to the shaft in the case where one line of shafting
has to be connected to another while running, (see Fig. 4).
In Fig. 2 the collar D grips the shaft, and is made in halves, and held in
position by bolts, it revolves with the shaft, the tongue t fits loosely in the groove
of the part C G. The object of this collar being to prevent the loose part C G.
from moving laterally along the shaft; when in or out of gear, it also serves to take
the end thrust during the short period of getting up speed, by the friction cone.
In Figs. 1 & 2 the part F. is half of an ordinary claw clutch, but having the
distance between the groove and the bottom of the claws prolonged. This part is
feathered to the shaft, and forms the bearing of the conical ring. The part E is the
cone shaped ring feathered on the part F. as aforesaid. This conical ring is pressed
against the blocks of hard wood or other suitable material 1. lining the pro-
jections H. H. H.
.
The manner in which the apparatus works is as follows:
The conical friction ring E is made to engage with the projections H. H. H.
of the loose part of the clutch, the result being that speed is rapidly got up, and
just as the full speed is attained by the loose part of the clutch, the part F. forming
the claw is caused to engage with the loose part CG., and this is effected without
the slightest jar or shock to any part of the apparatus, because when the speed of the
fixed and loose parts are almost the same; there can only be a very small relative
motion between the two in question, owing to this fact the claws can be easily
engaged, and do not occupy much time in so doing.
To avoid the danger of trying to engage the claw part of the clutch first, I make
the striking in and out of gear lever; of the friction clutch, lock the striking in and
out of gear lever of the claw clutch, in such a manner that the claw lever cannot be
shifted until the friction lever has thrown the friction cone into gear first.

page_text: To carry out my idea I use a form of double guide for the levers; in which the
friction lever is denoted by 1 and 1', and slides above the claw lever 2 and 21 as
indicated by Fig. 3. When the clutch is out of gear, the levers are in the position
marked 1 and 2 and are shown by the dotted lines. When the clutch is engaged;
or in gear the levers are in the position marked 1 and 2, and shown by the full lines.
Under the friction lever, and along the bottom guide bar, there is fixed a flat stee!
spring, marked 3, Fig. 3, held at one end by the bolt that keeps the guide together
and in position.
The free end of the spring carries a conical pin or stud marked 4. When both
levers occupy the position 11 and 21 or out of gear, the friction lever 1' presses down
the spring 3 and so keeps the pin or stud 4 down into a conical hole in the claw
lever 21.
Now when the friction lever is moved to the left so as to occupy the position 1, or
in gear, as it slides along, it permits the spring 3 to rise, and so the pin or stud
gradually ascends out of the hole in the claw lever 21. The pin and its corresponding
hole are made of such a depth that it will not become free from the lever 21, until
the friction lever 1' has travelled to such a distance to the left as to bring up the
speed of the loose part of the clutch by means of the friction cone, to a safe percentage
of the full speed. So soon as the pin is free from the lever 21, the claw lever is free
to occupy the position 2 or in gear, and can be held in this position by a pin passing
through a hole in the guides and claw lever.
In the drawing the levers are not shown, only in the locking arrangement; as
the levers of the ordinary claw clutches are used.
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
1st. A combination of the principles of a claw and friction clutch, whereby the
advantages arising from each are jointly utilised.
2nd. By the combination I overcome the difficulty of slipping arising from the
use of a friction clutch alone, and also the difficulty of engaging a claw clutch while
running.
3rd. There is no end thrust on the shaft only for the short period of getting up
speed.
4th. The clutch takes only about the same amount of room on the shaft as the
ordinary claw clutch, being much less than ordinary friction clutches, and can be
made very light.
5th. A locking arrangement as applied to both the striking in and out of gear
levers, actuating the friction and claw clutches; whereby the claw clutch cannot be
engaged until after a safe speed has been obtained, by the prior engagement of the
friction clutch.
Dated thie 19th day of June 1800