Improvements in Connecting the Rotating Parts of " Grab-cranes and other Machines.
Year: 1890

page_text: Date of Application, 24th June, 1890-Accepted, 30th Aug., 1890
COMPLETE SPECIFICATION.
Improvements in Connecting the Rotating Parts of " Grab-cranes
and other Machines.
1, CHARLES WILLIAM MACLEAN, of 276, Walsh Street, South Yarra, Melbourne, in
the Colony of Victoria, 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 :-
"
This invention relates to means for connecting two rotating parts in "grab-cranes
and other machines, so that the said parts may revolve at the same speed, or so that
either. part may remain stationary for one, or for less or more than one, revolution, or
for a predetermined number of revolutions, whilst the other part continues to rotate
or rotates in the reverse direction.
By the use of my invention, the weight hitherto employed for taking up the slack in
the opening chain of a "grab-crane" is dispensed with; the main hoisting drum and
the opening drum used for operating the grab being so connected to one another that
they may be disconnected whenever it becomes necessary for one to remain stationary
whilst the other rotates for the purpose of closing or opening the grab.
In carrying out this invention, there is or are employed one or more rings or collars
fitting loosely upon the shaft on which the two drums or other rotating parts to be
connected are mounted; each ring or collar being provided with a radially-projecting
arm, or with teeth or projections adapted to engage with other teeth or projections
formed on the adjacent faces of the two drums or other rotating parts.
In the accompanying drawings,
Fig. 1. represents, in vertical section, one of the simplest forms of my invention;
Fig. 2 being a transverse section on the line 2, 2.
Figs. 3 and 4 are respectively a side and an end elevation of the additional arm
shewn in Figs. 5 and 6.
Fig. 5 illustrates, in vertical section, a construction in which one part can rotate
independently of the other part for nearly three revolutions;
Fig. 6 being a corresponding transverse section on the line 6, 6.
In the design shewn in Fig. 7, the mechanism is more compact.
Fig. 8 is a transverse section on the line 8, 8.
Fig. 9 is a front elevation
Fig. 10 a vertical section on the line 10, 10, and
Fig. 11 a side elevation of the connecting ring.
In Fig. 12, a second ring is added ;
Fig. 13 being a transverse section on the line 13, 13.
Figs. 14 and 15 illustrate a modification of the construction represented in Figs. 5
and 6.
Fig. 16 shews, in longitudinal section, a pair of chain-drums fitted with my inven-
tion and adapted for hoisting and operating the grab in a "grab-crane."
Fig. 17 is an end elevation of one extremity of the larger drum.
Fig. 18 is a front elevation of the toothed connecting ring.
Fig. 19 is a transverse section on the line 19, 19.
Figs. 20 and 21 are respectively a side and a front elevation of a "grab-crane
furnished with the improved chain-drums.
"
Fig. 22 is a longitudinal section shewing the way in which my invention may be
applied for connecting two parallel shafts ;
Fig. 23 being a transverse section on the line 23, 23.
A and B are two discs; A being the driving and B the driven disc. They are
mounted upon a shaft or axle C, and are employed to represent the two drums or other
rotating parts which it is desired to connect in such a way that, after they have rotated
D

page_text: together for a time, the driven part (B) may continue to rotate for one, or for less or
more than one, revolution, or for any predetermined number of revolutions, whilst the
driving part (A) remains stationary; or so that the driven part (B) may be stopped
and the driving part (A) rotated in the reverse direction for one, or for less or more
than one, revolution, or for any predetermined number of revolutions.
Between the two discs A and B, and upon the shaft C, is loosely mounted a ring or
collar D having a radially-projecting arm d adapted to be engaged by the pin don
the disc A and to engage with the pin d2 on the disc B, or vice versa.
The arm or
lug d serves as a connection between the discs, in order that, if one disc be caused
to revolve, the other disc will also revolve. If it be desired to stop the driving
disc (A), the driven disc (B) will be free to continue its motion for nearly two
revolutions; that is, whilst the pin (d) on the driven disc is travelling round to the
extent indicated by the arrow 1, and whilst the said pin (d) is carrying round the arm d
to the extent indicated by the arrow 2, whereupon further movement is prevented by
the pin (d) on the driving disc, unless that disc be released. Or the driving disc (A)
may be reversed until the pin (d') thereon has carried the arm d round from one side
to the other side of the pin (d2) on the driven disc.
If a second ring D* furnished with an arm d* having a projecting pin d3 (Figs. 3
to 6) he mounted on the shaft C along-side the arm d, then the two discs A and B will
each be free to rotate independently during nearly three revolutions. Still greater
freedom for independent rotation may be obtained by mounting additional rings D*
with arms d* between the discs A and B, as will be readily understood. The pin d
on the disc B must be free to pass the pin d³, or the nearer or nearest pin d³ if there
be more than one..
The modification of my invention shewn in Figs. 7 and 8 is intended for use where
it is desirable to keep the diameter of the coupling connections as small as
possible.
The collars or hubs A and B are mounted on the shaft or axle C; each collar or
hub being formed with an annular recess containing a tooth d¹ or d². These tooth
engage with the teeth d d on a loosely-fitting ring D, carried by the shaft C. The
action of the ring D is the same as that of the arm d in Figs. 1 and 2. A second
toothed ring D* may be added, as illustrated in Figs. 12 and 13. The ring D* acts
in the same way as the arm d and pin d³ in Figs. 3 to 6. The number of additional
rings such as D* may be increased to any extent, according to the number of revolutions
during which it is desired that one collar or hub should be free to rotate whilst the
other remains stationary.
The arrangement illustrated in Figs. 14 and 15 is substantially the same as that
illustrated in Figs. 5 and 6; the principal difference being that projecting stops d'
and are used instead of pins. This arrangement will be understood from the
drawings without further description.
I will now proceed, by way of example, to describe with reference to Figs. 16 to 21
the application of my invention to the operating mechanism of an ordinary "grab-"
crane.'
"
A is the drum upon which the chain used for closing and hoisting the grab is
coiled. E is a wheel which can be put into gear with the driving mechanism, or
which can be stopped and held by means of a suitably-arranged brake F (Figs. 20
and 21). B is the drum upon which the grab-opening chain is coiled e is a brake-
wheel whereby the drum B may be held stationary. The adjacnt ends of the
drums A and B are formed with recesses, each of which contains atooth d¹ or d²
(Figs. 16 and 17). Two toothed rings D and D* are loosely mounted upon the
shaft C in such a manner that their teeth and the teeth d¹ and d engage with one
another as hereinbefore described with reference to Figs. 7 and 8. The end of the
grab-opening chain H is made fast to the drum B; the end of the hoisting chain J
being attached to the drum A.
The action of the crane is as follows:-
Assuming that the grab I has been closed and is being hoisted by the chain J, then
the chain H is slack and is wound upon the drum B at the same rate as the chain J

page_text: is wound upon the drum A, because, for the time being, the drum A is driving the
drum B through the instrumentality of the teeth on the rings and the teeth d¹ and d².
When it is desired to open the grab, the drum B is stopped by means of the brake f
and the brake-wheel e; the drum A being also thrown out of gear with the driving
mechanism and allowed to run backwards until the weight of the grab is transferred
to the opening chain, whereupon the grab is opened and its contents discharged. In
order to lower the grab, the brake fis slightly released; the open grab being lowered
by the chain H, whilst the chain J runs out freely. When the grab has dropped on
the spoil, the brake fis released. The drum A is then caused to wind up the chain J,
the drum B remaining stationary until the grab is closed, whereupon both drums rotate
together until the grab has been raised to the proper height.
In Fig. 22, the drums A and B, instead of being carried by the same shaft, are
keyed on two shafts C and C' arranged parallel with one another. These shafts are
connected by two spur-wheels G and G. The spur-wheel G is mounted to rotate
on the shaft C; the spur-wheel G' being keyed to the shaft (₁. The independent
rotation of the spur-wheel G on the shaft C is controlled by collars D and D*
furnished with arms d and d* engaging with stops d' and d² (Fig. 23) in the manner
previously described. The stop d² is formed on a flanged disc G* keyed on the
shaft (. By these means, the driving shaft (C) can rotate for nearly three revolutions
whilst the driven shaft (C) remains stationary, or vice versa.
My invention may be applied in any machine in which two rotating objects are
required to be connected in the manner hereinbefore set forth.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :—
"
1. The improved means for connecting two rotating parts of a grab-crane" or
other machine so that the said parts may revolve at the same speed, or so that
either part may remain stationary for one, or for less or more than one, revolution, or
for a predetermined number of revolutions, whilst the other part rotates, substantially
as herein described; such means comprising one or more movable rings or collars
furnished with an arm or arms or with teeth for enabling motion to be communicated
in either direction from one part to the other part.
2. In a "grab-crane" or other machine, the combination, with the rotating parts A
and B carrying pins or stops d¹ and d³, of the ring or collar D furnished with an
arm d, substantially as and for the purposes set forth.
.3. In a "
"
grab-crane or other machine, the combination, with the rotating
parts A and B carrying pins or stops d' and d², of two or more rings or collars D
and D*, one being furnished with an. arm d and the other or each of the
others with an arm d* and pin d³, substantially as and for the purposes set forth.
4. In a " grab-crane or other machine, the combination, with the rotating
parts A and B furnished with teeth d¹ and d², of a loosely-fitting toothed ring D, or a
toothed ring D and one or more toothed rings D*, substantially as and for the purposes
set forth.
5. In a "grab-crane" or other machine, the combination, with the shaft C¹ and the
toothed wheel G', of the shaft C, the toothed wheel G, the stop d', the ring D or the
rings D and D* furnished with an arm d or with the arms d and d*, the stop d², and
the disc G*, substantially as and for the purposes set forth.
6. In a "grab-crane," the improved means for connecting the drums A and B
arranged and operating substantially as described with reference to Figs. 16 to 21 of
the accompanying drawings.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Agent for the Applicant.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Agent for the Applicant.