Improvements in Crane Blocks for Suspending "Dogs or " Grabs."
Year: 1893

page_text: Date of Application, 20th Mar., 1893-Accepted, 22nd Apr., 1893
COMPLETE SPECIFICATION.
"
Improvements in Crane Blocks for Suspending "Dogs or
" Grabs."
I, FRANK WESLEY DICK, Steel and Iron Works Department, Messrs. Palmer's
Shipbuilding and Iron Company Limited Jarrow on Tyne in the County of
Durham, Engineer and Manager of Steel and Iron Works do hereby declare the
nature of this invention and in what manner the am is to be performed to be
particularly described and ascertained in and by the following statement :—
This invention relates to the blocks used in connection with "dog" or "grabs"
which are opened and closed by a supplementary or auxiliary chain.
When the usual form of chain or wire rope block is employed at the end of a
crane chain or rope in conjunction with such "dogs" or "grabs" and the "dogs"
or grabs are suspended from the hook in the usual manner they can only be
opened or closed properly by the auxiliary chain or connection when in one position,
relatively to the plane of the crane chains or ropes and if the "dogs" or "grabs
are twisted into any other position as is frequently necessary, the auxiliary or
supplementary chain or connection fouls the crane chains or ropes and is liable to
become locked.
In this improved block, which has a double sheave, the difficulty is overcome by
the use of a hollow pillar, preferably forming a prolongation of the crosshead,
which carries the two sheaves, upon which is mounted, a double hook free to rotate
around the axis (preferably upon rolling balls, running in a path formed in a collar
secured upon the bottom end of the hollow pillar), and from each hook a chain or
link is attached to one of the lever arms of the "dogs or grabs" which can
thus be twisted into any position round the axis of the hollow pillar. The
supplementary chain or connection to operate the "dogs" or "grabs" passes
upward through the hollow pillar and crosshead to the crane and as its axis is
coincident with the axis of rotation of the hooks no fouling of the crane chains or
FALO.
مسلسل سوم
46
On the accompanying drawing a crane block is shewn constructed according to
this invention a portion only of the lever arms of the "dogs" or "grabs" being
shewn:-
A Aare the chain sheaves mounted on the crosshead B which extends downward
and forms the hollow pillar (upon which are the hooks D D' rotating upon the
balls E (which are confined in a recess) in a grooved path in the collar F secured
on the end of the hollow pillar C. The supplementary chain (for operating the
main or lever arms H. of the "dogs" or "grabs" passes from the arm J upward
through the centre of the hollow pillar C to the operating mechanism on the
crane.
་་
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
"
or "
First. The improvements in crane blocks for suspending “dogs grabs,"
consisting in mounting a double hook, rotating around a centre coincident with
that of a pair of chain or rope sheaves, through which centre a chain or other
connection, for operating the lever arms or jaws of the "dogs or "grabs" passes
from an arm or link thereon upward to the crane for the purposes hereinbefore
described.
"

page_text: "
"
Second. The construction and application of chain blocks for suspending "dogs
or grabs" consisting of a pair of chain sheaves A. A' mounted upon a "trunnion
crosshead B a prolongation of which forms a pillar C, upon which is mounted a
double look D. D' so as to rotate upon balls E running in a sunk path or on a collar F
secured on the end of the pillar C; the "dogs" or "grabs" being suspended by
chains from the double hook and a supplementary chain G, from the arm, passing
upward to the crane through a hole, traversing the centre of the pillar Cand
crosshead B, coincident with the centre of the double hook and of the chain
shenves A A', for the purposes hereinbefore stated substantially as described and
shewn.
Batad this outh day of March 1902
T. J. DANSON, F. Inst. P.A.,
Chartered Patent Agent,
Newcastle-upon-Tyne, Agent for Applicant.
T. J. DANSON, F. Inst. P.A.,
Chartered Patent Agent,
Newcastle-upon-Tyne, Agent for Applicant.