Improvements in Safety Clutches.
Year: 1897

page_text: Date of Application, 28th Sept., 1897-Accepted 6th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in Safety Clutches.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention (which has been communicated to me from abroad by the Société des
Mines & Fonderies de Zinc de la Vieille Montagne, of Angleur par Chênée,
Belgium) 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 the construction of a clutch in such a manner that the
driving force transmitted through it from a motor, especially one having a fly-
wheel, to any machinery, but especially to a rolling mill, can be limited to a
certain amount which it cannot exceed. Such a clutch operates as a safety clutch,
firmly connecting the machinery to the engine during normal working, but auto-
matically disengaging them under excessive strain.
This provides against sudden stoppage of the motor and preserves industrial
establishments from losses of life and property such as result from bursting of fly.
wheels and like accidents due to sudden stoppages.
Attempts have long been made to solve this problem by the use of friction
clutches and the like, but though these are called safety clutches, they do not set
the machines free, and during their action, when they do act, they cause shocks
and vibrations which are very prejudicial, and they, after all, constitute an
expedient which has many objections and very doubtful advantages.
Without farther discussing this matter, which had to be referred to in order to
shew the importance of the problem and the difficulties attending its solution.
I shall now describe the arrangement, which is comparatively simple, and the
action of the apparatus, which, after many trials and modifications is found to
solve successfully the problem to which the invention is directed, referring to the
accompanying drawings.
Figure 1 is a section and Figure 2 an elevation shewing one construction of
clutch according to this invention. Figure 1 is a section of one of the cranks,
Figure 2 is a part back view of the disc M'.
Figures 3 and 4 are respectively a section and an elevation of a modified form
of clutch.
Figures 5 and 6 are similar views shewing another modification, Figure 5* is
a section of part of the toggle.
The apparatus shewn in Figures 1, 2, 1^, 2ª consists of two discs M M¹ fixed face
to face one on each of the two shafts that have to be coupled. The disc M has
projecting from its periphery a number of studs t forming pivots on which can
freely turn cranks m each having on its crank pin an approximately rectangular
block c free to turn. The other disc M' has bolted on it two rings C and Ca
between which, another ring C¹ is fitted free to slide, springs being interposed
between it and C. On the face of C₁ are inclines e corresponding in number to
the cranks m and facing each incline there is a tooth n projecting from the ring C²,

page_text: these teeth being separated by notches through which the crank blocks e can
pass when the clutch becomes disengaged.
The operation is as follows:-
All the cranks m are passed over the teeth n of C2 so that their blocks c bear
against the inclines e, being held between them and the teeth: A blade
spring el, of which there may be several, acts as a buffer when the ring C¹ springs
back after escape of the crank blocks c.
'
When M revolves the blocks c acting on the inclines e push back the ring C
compressing the springs r. Should the resistance of M¹ exceed that for which
the springs are adjusted, the blocks c, on passing the position shewn in dotted
lines at c will escape through the notches of the ring C³ allowing M to revolve
freely.
Obviously if M¹ be the driving and M the driven disc, the action is the same,
M¹ being left free on the escape of the. crank blocks c.
A safety clutch such as that above described
(1) Serves to limit the power transmitted from an engine more efficiently than
friction or other slip clutches,
(2) and, what is most important, when it automatically disengages, it sets the
driver completely free, thus avoiding all the dangers to which machinery provided
with other clutches is liable.
This new safety apparatus should therefore be of great service in the many cases
where it is desired to provide against the destructive effects of force accumulated
in flywheels, when, from any cause, abnormal resistance is encountered.
It is also of the highest importance as providing against danger to human life
in such cases.
In the modified apparatus shewn in Figures 3 and 4, the disc M has on its face
a number of projections d on each of which is pivotted a block t. On the disc M¹
is fixed a ring C and is fitted a longitudinally moveable ring C, with springs r
interposed between C and C¹. From M¹ there project a number of studs p on each
of which is pivotted a double crank m with rollers on its crank pins, and the
ring has a recess facing each crank. As M revolves, the blocks force the
cranks m round towards the dotted position, the springs r being thus com-
pressed until the cranks escape from the recesses of C¹, and then M is free to
revolve.
In the modified clutch shewn in Figures 5, 5 and 6, the cranks m instead of
engaging in recesses of the ring C, are connected to it by toggle links g by which
the springs are compressed until, after passing their dead centres, the toggles
bring the cranks into a position where they are entirely free from the action of
the blocks t, the disc M. then revolving freely.
Having now particularly described and ascertained, the nature of this
Invention and in what manner the same is to be performed, I declare that what
I claim is-
1. A safety clutch constructed and operating substantially as described with
reference to Figures 1, 14, 2, 24.
2. The modified safety clutch constructed and operating substantially as
described with reference to Figures 3 and 4.
3. The modified safety clutch constructed and operating substantially as
described with reference to Figures 5, 5 and 6.
Dated this 28th day of September 1897.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Date of Application, 28th Sept., 1897-Accepted, 6th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in Safety Clutches.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent do hereby declare the nature of this
invention (which has been communicated to me from abroad by the Societe des
Mines & Fonderies de Zinc de la Vielle Montagne, of Angleur par Chenee,
Belgium) 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 the construction of a clutch in such a manner that the
driving force transmitted through it from a motor, especially one having a fly-
wheel to any machinery, but especially to a rolling mill, can be limited to a
certain amount which it cannot exceed. Such a clutch operates as a safety clutch,
firmly connecting the machinery to the engine during normal working, but auto-
matically disengaging them under excessive strain.
This provides against sudden stoppage of the motor and preserves industrial
establishments from losses of life and property such as result from bursting of fly-
Attempts have long been made to solve this problem by the use of friction
wheels and like accidents due to sudden stoppages.
clutches and the like, but though these are called safety clutches, they do not set
the machines free, and during their action, when they do act, they cause shocks
and vibrations which are very prejudicial, and they, after all, constitute an
expedient which has many objections and very doubtful advantages.
Without farther discussing this matter, which had to be referred to in order to
shew the importance of the problem and the difficulties attending its solution.
I shall now describe the arrangement, which is comparatively simple, and the
action of the apparatus, which, after many trials and modifications is found to
solve successfully the problem 'to which the invention is directed, referring to the
accompanying drawings.
Figure 1 is a section and Figure 2 an elevation shewing one construction of
clutch according to this invention. Figure 1' is a section of one of the cranks,
Figure 2 is a part back view of the disc M'.
Figures 3 and
of clutch.
are respectively a section and an elevation of a modified form
Figures 5 and 6 are similar views shewing another modification, Figure 5* is
a section of part of the toggle.
The apparatus shewn in Figures 1, 2, 1^, 2^ consists of two discs M M¹ fixed face
to face one on each of the two shafts that have to be coupled. The 'disc M has
projecting from its periphery a number of studs & forming pivots on which can
freely turn cranks m each having on its crank pin an approximately rectangular
block c free to turn. The other disc M has bolted on it two rings C and C²
between which another ring C¹ is fitted free to slide, springs r being interposed
between it and C. On the face of C¹ are inclines e corresponding in number to
the cranks m and facing each incline there is a tooth n projecting from the ring C³,

page_text: these teeth being separated by notches through which the crank blocks c can
pass when the clutch becomes disengaged.
The operation is as follows:-
All the cranks m are passed over the teeth n of C2 so that their blocks c bear
against the inclines e being held between them and the teeth n. A blade
spring el, of which there may be several, acts as a buffer when the ring C¹ springs
back after escape of the crank blocks c.
When M revolves the blocks c acting on the inclines e push back the ring C
compressing the springs r. Should the resistance of M¹ exceed that for which
the springs are adjusted, the blocks e, on passing the position shewn in dotted
lines at c¹ will escape through the notches of the ring C2 allowing M to revolve
freely.
:
Obviously if M¹ be the driving and M the driven disc, the action is the same,
M¹ being left free on the escape of the crank blocks c.
A safety clutch such as that above described
(1) Serves to limit the power transmitted from an engine more efficiently than
friction or other slip clutches,--
(2) and, what is most important, when it automatically disengages, it sets the
driver completely free, thus avoiding all the dangers to which machinery provided
with other clutches is liable.
This new safety apparatus should therefore be of great service in the many cases
where it is desired to provide against the destructive effects of force accumulated
in flywheels, when, from any cause, abnormal resistance is encountered.
It is also of the highest importance as providing against danger to human life
in such cases.
t
In the modified apparatus shewn in Figures 3 and 4, the disc M has on its face
a number of projections d on each of which is pivotted a block t. On the disc M¹
is fixed a ring C and is fitted a longitudinally moveable ring C, with springs r
interposed between C and C¹. From M¹ there project a number of studs on each
of which is pivotted a double crank m with rollers on its crank pins, and the
ring C¹ has a recess facing each crank. As M revolves, the blocks t force the
cranks m round towards the dotted position, the springs being thus com-
pressed until the cranks escape from the recesses of C¹, and then M is free to
revolve.
In the modified clutch shewn in Figures 5, 5 and 6, the cranks m instead of
engaging in recesses of the ring C¹, are connected to it by toggle links g by which
the springs are compressed until, after passing their dead centres, the toggles
being the cranks into a position where they are entirely free from the action of
the blocks t, the disc M then revolving freely.
Having now particularly described and ascertained the nature of this
Invention and in what manner the same is to be performed, I declare that what
I claim is:-
'
1. A safety clutch constructed and operating substantially as described with
reference to Figures 1, 14, 2, 2ª.
2. The modified safety clutch constructed and operating substantially as
described with reference to Figures 3 and 4.
3. The modified safety clutch constructed and operating substantially as
described with reference to Figures 5, 5 and 6.
Dated this 28th day of September 1897.
ABEL & IMRAY,
Agents for the 'Applicant.