Year: 1887

page_text: I, SAMUEL CHARLES HARRIS, of 37 Walbrook, London, E.C., in the County of
Middlesex, Engineer, do hereby declare the nature of this invention to be as
follows:
To obtain the necessary purchase for opening and closing iny Dredger, and to
dispense with the use of any extraneous gear at the Jib head of the crane, or other
means used for working the Dredger, I use a Return chain, that is to say, the chain
is carried over the Jib head sheave, or may come direct from the barrel of the crab or
other appliance used, and after passing over the sheaves, or barrel of the Dredger, is
brought up to the Jib head or other attachment, and fastened by means of a Hook
and Shackle, or other suitable arrangement.
The chain from the hook is first carried under a Cup drum or Spocket wheel on the
sliding crosshead, and over a specially arranged sheave on the cross frame which
connects the two Guide frames, and then continued downward, and under a sheave or
sheaves arranged on the centre of the Dredger in the same position usually occupied
by the Differential barrel, and over a sheave or sheaves carried in the cross-head to
which the links of the Dredger are connected, and which also slides upon the Guide
frames.
The cup drum or spocket wheel has a ratchet wheel cast upon or otherwise fixed
to it, and when lowering away the Dredger, the opening movement is obtained by
holding the Ratchet wheel, and thus preventing the Cup drum from turning, and this
Cup drum being on the cross head, and the other end of the Return chain being
slacked off, the Dredger falls
open.
To hold the Ratchet wheel use a specially constructed Tumbler which is pivotted
upon the cross head, and the bottom of this Tumbler engages in the Ratchet wheel
either directly or through a Pawl or other contrivance, and the top of the Tumbler is
arranged to bear against the Side frame or frames until the Dredger is wide open,
when it is pushed into a recess, formed on the top of the Side guide frame, by the
pressure of the Ratchet wheel against the bottom of the Tumbler, either directly or
through the Pawl, and as the motion of the Tumbler releases the Ratchet wheel, the
077

page_text: Cup drum or Spocket wheel is free to turn, and the Dredger is lowered away without
the use of Brakes or other gear.
On touching the ground, the Tumbler falls out of the Recess in the side guide
frame by its own weight, being made specially of such a shape that the weight
preponderates on one side, and on the chain being hauled up the Dredger first closes
without rising from the ground, but digging into it by the downward pressure obtained
by the peculiar arrangement of the chains and sheaves, and when closed it rises to any
desired height, and is lowered away, the Tumbler and Ratchet coming into gear as
before.
As the Ratchet wheel moves in opposite directions according as the Dredger is
lifted or lowered, the Pawl, as used in combination with the Tumbler, is weighted so
that it falls clear when released from the teeth of the Ratchet wheel, and so allows
for the opposite motions of the Ratchet wheel-In order to push the Tumbler;.or
combined Pawl and Tumbler into gear with the Ratchet wheel, a prolongation of the
Pawl or Tumbler comes in contact with a stud or stop of suitable shape fixed to the
bottom of the side frame.
1 prefer to fix the Cup Drum or spocket wheel out of the centre of the cross head,
so that the Return chain may be central with the Dredger if found necessary.
I also arrange the Dredger without side or guide frames, the gear being sub-
stantially as described, but I retain the Dredger in an open position by holding the
suspending links together. This is done by making the Tumbler of such a shape
that one end of it grips a stud or suitable projection on one link or pair of links, the
Tumbler being pivotted on the other link or links.
The end of the Tumbler which grips the first mentioned links is pushed into gear
with the stud or projection at the same moment that it clears the Ratchet wheel, as
described in the first arrangement, the stud or projection being used instead of the
recess before mentioned.
Instead of the spocket wheel I use a barrel with the chain passed once or more
round it, this barrel being applicable to either arrangement, but more especially to that
last described.
Dated this Second day of March 1887.

page_text: I SAMUEL CHARLES HARRIS of 37 Walbrook, London, E.C., in the County of
Middlesex, 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 :-
To obtain the necessary purchase for opening and closing my Dredger, and to
dispense with the use of any extraneous gear at the Jib head of the crane, or other
means used for working the Dredger, I use a Return chain, that is to say, the chain
is carried over the Jib head sheave, or may come direct from the barrel of the crab
or other appliance used, and after passing over the sheaves, or barrel of the Dredger,
is brought up to the Jib head or other attachment, and fastened by means of a Hook
and Shackle, or other suitable arrangement. The chain from the Hook is first carried
under a cup drum or Sprocket wheel on the sliding cross head, and over a specially
arranged sheave on the cross frame if found necessary, and then continued downwards,
and under a sheave or sheaves arranged on the centre of the Dredger in the same
position occupied by the differential barrel, and over a sheave or sheaves carried in
the cross head to which the links of the Dredger are connected, and which also slides
upon the guide frames.
The cup drum or sprocket wheel has a ratchet wheel cast upon or otherwise fixed
to it, and when lowering away the Dredger, the opening movement is obtained by
holding the Ratchet wheel, and thus preventing the cup drum from turning, and this
cup drum being on the Cross-head, and the other end of the Return chain being
slacked off, the Dredger falls open.
To hold the Ratchet wheel A. figure 1, I use a specially constructed Tumbler B.
which is pivotted upon the cross head C., and the bottom of this Tumbler engages in
the Ratchet wheel either directly or through a Pawl or other contrivance, and the top
of the Tumbler is arranged to bear against the side frame or frames until the Dredger
is wide open, when it is pushed into a recess formed on the top of the side guide frames
by the pressure of the Ratchet wheel against the bottom of the Tumbler, either
directly or through a Pawl, and as the motion of the Tumbler releases the Ratchet
wheel, the cup drum or spocket wheel is free to turn, and the Dredger is lowered
away without the use of brakes or other gear, except the machinery of the crane which
may be used to work it.
Ön touching the ground, the Tumbler B falls out of the Recess D. in the side guide
frames by its own weight, being of such a shape that the weight preponderates on one
side, and on the chain being hauled up the Dredger first closes without rising from
the ground, but digging into it by the downward pressure obtained by the peculiar
arrangement of the chains and sheaves, and when closed it rises to any desired height,
and is lowered away, the Tumbler and Ratchet coming into gear as before.
As the Ratchet wheel moves in opposite directions, according as the Dredger is
lifted or lowered, the Pawl E. as used in combination with the Tumbler is weighted

page_text: so that it falls clear when released from the teeth of the Ratchet wheel, and so allows
for the opposite motions of the Ratchet wheel. In order to push the Tumbler, or
combined Pawl and Tumbler into gear with the Ratchet wheel, a prolongation of the
Pawl or Tumbler may come into contact with a suitable stud or stop at the bottom of
the side guide frame, or the specially contrived Pawl F. may be used, and is actuated
on the motion of the Ratchet wheel being reversed by a recess or tooth being formed
for this purpose.
I prefer to fix the cup drum or sprocket wheel out of the centre of the cross head,
so that the Return chain may be central with the Dredger if found necessary.
I also arrange the Dredger without side or guide frames, the gear being substantially
as described, but I retain the Dredger in an open position by holding the suspending
links A. figure 2. together. This is done by making the Tumbler B. of such a shape
that one end of it grips a stud or suitable projection on one link or pair of links, the
Tumbler being pivotted on the other link or links.
The end of the Tumbler which grips the first mentioned links is pushed into gear
with the stud or projection at the same moment that it clears the Ratchet wheel, as
described in the first arrangement, the stud or projection C. being used instead of the
recess before mentioned.
Instead of the sprocket wheel, I use a barrel D. with the chain passed once or more
round it, this barrel being applicable to either arrangement, but more especially to
that last described.
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 method of recving the chain.
2. The combination of the cup drum or sprocket wheel with the Ratchet wheel.
3. The Tumbler as described and shewn in the drawings.
4. The combination of the Tumbler and Pawl.
5. The stop for pushing the Pawl into gear with the Ratchet wheel.
6. The specially contrived Pawl for the same purpose, as described.
Dated 11.
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