Improvements in or connected with the Design and Construction of Boats' Davits and Chook Rests.
Year: 1893

page_text: Date of Application, 11th Apr., 1893-Accepted, 20th May, 1893
COMI DEID STIMULEIOAI
Improvements in or connected with the Design and Construction of
Boats' Davits and Chook Rests.
We, GEORGE ROCKLIFFE, Mariner of 11 Sans Street, JOHN MAUGHAN,
Pattern Maker of 147 High Street, East, and WILLIAM KEY, Army Contractor
of Tavistock House all in Sunderland in the County of Durham 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 improvements in or connected with the design and
construction of boats' davits and chock rests and has for its object greater facility
in working the davits by certain special and novel combinations of parts whereby
friction is reduced to a minimum. The improved arrangement prevents access of
dust to the working parts and is at the same time very simple in design.
We will describe our invention with reference to the accompanying drawings in
which
Figure 1 shows a sectional elevation and Figure an end view of the socket in
which the spindle of the davit works.
Figure 3 is a side view of the dust-proof cap and
Figure 4 an elevation partly in section of an improved construction in boats
davits both of which figures are fully hereinafter described and in the following
Specification like marks of reference designate like parts.
Referring to Figs. 1, 2 and 3 of the drawings a is the davit spindle socket. To
reduce the friction of the revolution of the spindle 1 we prefer to introduce at the
base of the socket a case-hardened metal step 2 between which and the bevelled
base of the spindle a ring of friction-bearing-balls 3 preferably of phosphor bronze
is designed to work. Similarly at the upper end of the socket we fit into a suitably
formed recess a case-hardened metal step 4 between which and the part 5 another
ring of similar friction-balls is designed to work. The part 5 is to be formed as
shown in the drawing with an annular lip 7 which projects over the upper edges of
the step 4 and in this manner practically prevents access of dust or water to the
ball bearings. Cast or forged in one with part 5 is a clamp 8 formed as shown
which by means of its elasticity and a bolt 9 can be securely clamped or fastened
to the spindle in any desired position by which arrangement the distribution of the
weights on the two sets of balls 3 and 6 can be nicely regulated and adjusted.
Cast on
or secured to the side of the socket a is a projection a' at which a
chock bearer bar 10 of any suitable design is centred. A rod or strut-bar 11 is
pivotted or hinged at 12 and by withdrawing the pin or bolt 13 connecting the
strut 11 to the chock-bearer the latter can be lowered so as to lie vertically
alongside the socket a when the boat indicated in dotted lines will.of-course-remain
suspended..
In Figure 4 the overhanging arm a² of the davit is shown cast or made separate
or detachable from the spindle shank 1. The socket of the detachable part is
tapered as shown and secured to the top of the spindle by a lock bolt or cotter B.
This arrangement will be found to be very convenient in practice as by its means
the top of the davit can be readily removed instead of having to remove the
The
whole davit as is at present the case when loading coals or in like instances.
detachable or bent part of the davit can be made of an I or equivalent section so as
to ensure an ample margin of strength.

page_text: Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:
1. In boat's davits the adjuncts to or the combination with the davit socket and
the spindle of the step 4 ball bearings 6 adjustable cap 5 with overhanging lip 7
and clamp 8 all arranged and adapted to operate substantially as and for the
purposes herein set forth.
2. In boat's davits the combination with the several parts named and claimed in
the preceding claim of the friction reducing media 3 at the base of the spindle
substantially as and for the purposes set forth.
3. The improved construction of boats' davits substantially as described and shown
with reference to Fig. 4 of the drawings.
4. The combination with boats' davit-sockets of radial chock-bearer and strut-
bars for facilitating the removal or replacement of the chocks the several parts
being arranged and adapted to operate substantially as shown and described with
reference to Figs. 1 and 2 of the drawings.
Dated this 6th day of April 1892
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.