An Improvement in Snatch Blocks,
Year: 1891

page_text: Date of Application, 6th Nov., 1891-Accepted, 12th Dec., 1891
COMPLETE SPECIFICATION.
An Improvement in Snatch Blocks,
I, WILLIAM JAMES; of 77 Eldon Street, South Shields; in the County of
Durham, Blacksmith, 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 :-
My invention relates to an improvement in snatch blocks.
Hitherto in snatch blocks, forelocks, cotters, pins, or similar mechanical appliances
have been used to secure in a shut position that hinged portion of the strap which
is laid back when the "bight" of the rope is to be inserted.
Such arrangements give unnecessary trouble and are very clumsy and inconvenient
in practical working and my invention consists in so arranging a specially devised
snap-joint as to dispense with the necessity for other mechanical fastenings.
I will fully describe my invention with reference to the accompanying drawings
in which
Figures 1 and 2 show end and side views of my improved device.
Similar letters of reference designate similar parts in the Specification and
drawings.
Referring to these figures, it will be observed that the portion 3 of the strap
which crosses the opening or snatch is hinged at 4 and that the portion 5 carrying
the hook 6 is hinged at 7.
Both of these hinged portions can thus obviously be made to assume the positions
shown in dotted lines. 8 is a spring which may or may not be used, though
I prefer to use it as shown, its office being to keep portion 3 in the position
shown in full lines in Fig. 1. The outer ends of portions 3 and 5 are to be
specially shaped substantially as shown in the drawing, and on the back of portion 3
some simple means for drawing it open (in opposition to the spring pressure) may
be employed. This may consist of an eye or projection 9 (to which a short cord or
chain may be attached) or any other such simple means may if found necessary be
used for more easily pulling back when desired the portion 3.
The operation of the device is thus as follows.
To insert the rope pull back portion 3 until the lip formed on the outer end of
portion 5 clears the hook-shaped formation on the end of 3. Hook 6 and portion 5
can then be thrown back in the ordinary way and the "bight" of the rope
inserted.
The special efficacy of the invention now comes into play, because the hook_6
and portion 5 can be immediately snapped to so as to become locked with the hook-
shaped formation on 3 as shown in the drawing, the lip on 5 being so formed as to
first automatically push back and then lock itself with the portion 3.
The utility of spring 8 will be here also clearly seen and the greater the pull on
the snatch block the tighter does the snap-joint hold.
The automatic action of the joint so formed not only simplifies the construction
of such gear but materially facilitates the working of the same.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The use in snatch blocks of a snap-joint consisting of a hook-shaped formation
on one hinged portion locking and unlocking with a lip-shaped formation on another

page_text: hinged portion the several parts being arranged and designed to operate substantially
as and for the purposes hereinbefore set forth.
Dated this 5th day of November 1891.
A. CRAWHALL CHAPMAN,
3, St. Nicholas' Buildings, Newcastle-on-Tyne, Patent Agent.