Improvements in Grabs and Excavators.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in Grabs and Excavators.
EDWARD GEORGE FIEGEHEN, Stafford Lodge, Ampthill Road, Bedford,
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in the clip gear for automatically
opening and closing single chain grabs and excavators, in which the whole
cycle of operations is performed by once hoisting and lowering the grab.
In the accompanying drawings Fig. 1 is a cross section through the crosshead
ard clip gear shewing the relation of parts just before the catches or hooks
engage the centre tube. Fig. 2 is an elevation of the same, partly sectional,
taken at right angles to Fig. 1. Fig. 3 is a similar cross section to Fig. 1
shewing relation of parts as catches are engaging and suspension hooks are dis-
engaging. Fig. 4 shews the action of the hood in returning the catches to the
off position when the open grab strikes the ground.
The suspension ring A is of the usual type, and is suspended at the requisite
height from the jib head by chains as usual.
The suspension hooks B are not solid with their shanks as is usual but are
jointed at C.
The gear on the grab itself consists of a hood 1) having ridges E and F running
round the interior, the former serving to press the hooks G into engagement with
the tube H and the latter (F) replacing them in the off position when the open grab
reaches the ground, as in Fig. 4, the hood also has an edge J with which the
suspension hooks B engage and the inner surface at K is bored to fit over a
Corresponding turned surface on the crosshead L.
The top of the hood D is preferably shaped as shewn forming a guide for the
suspension hooks and covering the whole mechanism.
The crosshead L is provided with lugs between which the hooks or catches G
and the distance pieces M (the latter merely serving to guide the hood) are
pivotted.
A circular lip substantially as shewn at N is provided on the crosshead casting
whose function is to trip the suspension hooks B at the moment when the hood in
rising has pressed the hooks G over the top of the tube H as shewn in Fig. 3.
The hood D) is preferably free to rotate in working to ensure even wear of the
working surfaces.
With the above arrangement I am enabled to dispense entirely with the use
of springs or slots which have manifest disadvantages in grabs, the parts are
enclosed and protected from injury and, to a larger extent than usual, from
grit. The moving parts moreover are not of such a nature as to be easily
deranged by grit.
Dated this 20th day of November 1899.

page_text: EDWARD GEORGE FIEGEHEN, Stafford Lodge, Ampthill Road, Bedford,
Mechanical Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
-
This invention relates to the clip gear for automatically opening and closing
single chain grabs and excavators, in which the whole cycle of operations is
periormed by once hoisting and lowering the grab.
In the drawings accompanying the Provisional Specification, Fig. 1 is a cross
section through the crosshead and clip gear shewing the relation of parts just
before the catches or hooks engage the centre tube. Fig. 2 is an elevation of the
same, partly sectional, taken at right angles to Fig. 1. Fig. 3 is a similar
cross section to Fig. 1 shewing relation of parts as catches are engaging and
suspension hooks are disengaging. Fig. 4 shews the action of the hood in
returning the catches to the off position when the open grab strikes the ground.
The suspension ring A is of the usual type and is suspended at the requisite
height from the jib head by chains as usual.
The suspension hooks B are not solid with their shanks as is usual but are
jointed at C.
The gear on the grab itself consists of a hood D having ridges E and F running
round the interior, the former serving to press the hooks G into engagement with
the tube H and the latter (F) replacing them in the off position when the open grab
reaches the ground, as in Fig. 4 the hood also has an edge J with which the
suspension hooks B engage and the inner surface at K is bored to fit over a
corresponding turned surface on the crosshead L.
The top of the hood D is preferably shaped as shewn forming a guide for the
suspension hooks and covering the whole mechanism.
The crosshead L is provided with lugs between which the hooks or catches G
and the distance pieces M (the latter merely serving to guide the hood) are
pivotted.
A circular lip substantially as shewn at N is provided on the crosshead casting
whose function is to trip the suspension hooks B at the moment when the hood in
rising has pressed the hooks G over the top of the tube H as shewn in Fig. 3.
The hood D is preferably free to rotate in working to ensure even wear of the
working surfaces.
The action of the gear is as follows:-
Assume the grab to be descending empty; the ridge F of the hood is resting
upon the projections at the back of the catches G tending to disengage them.
When the grab bucket touches the ground the central tube will slide a short
distance through the crosshead L. The catches G being thus freed will be
returned to the off position by the weight of the hood D, as shewn in Fig. 4.
The crane chain is now hoisted and the grab fills itself and ascends until the
hood D is engaged by the suspension hooks B.
On lowering the crane chain the grab discharges itself the catches G sliding up
the tube H.
7
On reaching the top of the tube, the catches G actuated by the ridge E are 4
forced over into engagement with the tube as shewn Fig. 1. In forcing the
catches over, the hood D rises to such an extent that the inner lip N on the
crosshead L forces the suspension hooks B to such a position that they slip, as
sbewn in Fig. 3 and disengaging, transfer the weight of the grab to the

page_text: catches G. The grab being thus locked open continues its descent and the
cycle is repeated.
With the above arrangement I am enabled to dispense entirely with the use
of springs or slots which have manifest disadvantages in grabs, the parts are
enclosed and protected from injury and, to a larger extent than usual, from
grit. The moving parts moreover are not of such a nature as to be easily
deranged by grit.
Having now particularly described and ascertained the nature of my in-
vention and in what manner the same is to be performed I declare that what
I claim is:-
1. The arrangement & combination of parts constituting an automatic trip
gear for grabs and excavators, substantially as described and illustrated in the
accompanying drawings.
2. The arrangement & combination of parts substantially as described and
illustrated, whereby a hook, whilst holding securely to an edge or projection,
may be made to slip or disengage with the said edge or projection, by the action
of a second edge or projection.
3. The combination in a trip gear for the purposes set forth, of a circular
rotatable hood D, and catches G substantially as described and illustrated whereby
the various operations are performed in the proper sequence, the whole mechanism
is enclosed, and the liability to wear or derangement reduced to a minimum.
Dated this 30th day of July 1900.