Improvements in Davits.
Year: 1899

page_text: Date of Application, 20th Feb., 1899-Accepted, 1st July, 1899
Improvements in Davits.
I, CARL SIXTUS OLSSON, of the City and County of San Francisco and State
of California, 66, Oregon Street, U.S.A., Ship's-carpenter, 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 detaching, hoisting and lowering
devices for ships-boats, which are familiarly known in the art as davits.
The ordinary devices of this class consist of two falls passing through double
blocks and suspended from the davits proper. The lower blocks hook into rings
at each end of the boat and are intended to be unhooked by hand after the boat
reaches the water. It is manifest that in lowering a boat in a heavy sea, this
arrangement is troublesome and dangerous, as a failure to detach both hooks simul-
taneously, may lead to the swamping of the boat.
To remedy this and provide a device having a minimum number of parts and
connecting tackle and one in which the parts are so assembled as to absolutely
obviate any liability of fatal results, are among the prime objects of my present
invention.
To the attainment of the foregoing and other useful ends my invention consists
in matter hereinafter set forth, reference being had to the accompanying drawings
in which similar reference letters designate corresponding parts in the several
views.
Figure is a perspective view of my improved davit.
Figure 2 is a side view of the detaching hook employed.
Figure 3 is an elevation of the detaching hook, taken at right angles to
Figure 2.
Figure 4 is a perspective view of the chocks employed.
Figure 5 is a section through line
Figure 1.
Figure 6 is a perspective view of a modified form of construction.
I will now explain in detail the construction and operation of my invention,
reference being had to the above figures.
The main body or foundation for the operative parts of my invention consists
of the member A which is provided with the projecting circular base-plate B, the
latter being mounted on the deck of the vessel in a manner hereinafter described.
Extending across the upper portion of the member A is the horizontal plate (c),
to which is rigidly secured and projects upward the thimble (b).
Leading upward from the thimble (b) and secured thereto as if formed integral
with member A is the crane or beam C whose upper extremity is curved and
outwardly reaching in the form of an ordinary davit.
Pivoted to the outer extremity of the beam C is the block D which is con-
nected to the fall-block E by means of a single tackle F. Suitable rings and eye-
bolts are secured to the bow and stern of the boat and wire guys f f lead to the
open member V which is attached to the fall-block E. In Figures 2 and 3 I
have shown a novel fall-hook which may be used to connect the guys f fl with
the member V, and I will hereinafter explain the construction of the same.

page_text: Slightly shorter than the crane C and adapted to slide in a cut-out or forked
grcove (h) in the plate (c) and in projecting guide G on the beam C, is the
secondary crane or beam H. The outer extremity of the crane H is free, while
its inner end is secured to the pivoted segmental gears I by means of the cross-
pin (). The teeth of these gears I mesh with the small pinions () which are
mounted in member A by means of the transverse shaft (j) the latter bearing
terminally the crank-handles (¹). The curved slot () is to permit the required
travel of the pin (i) as the segmental gears are operated.
To lessen the friction and permit free extension of the beam H as the segmental
gears are operated, I have provided the friction roller (m).
It will be readily seen that as the tackle F is drawn in, assuming that the parts
are in the relative positions shown in Figure 1, the roller (2) will be drawn out-
ward on the beam H carrying with it the suspended boat. But the moment the
roller (p) reaches the outer extremity of the beam H the suspended boat is free
to be lowered, as the outer block on the beam C reaches beyond the outer
extremity of the beam H.
Now in taking in the boat the tackle F is drawn in until the fall-block E reaches
the block 1, when by turning the segmental gears I, the beam H will slide up-
ward and outward and in so doing its outer extremity will be immediately below
the roller p. By simply releasing the tackle F the roller will roll by gravity
down the small beam H into its former normal position.
I will now explain the manner of mounting the plate B on the deck:-The
central shank or stem S passes downward through a perforation in the deck and
is held in a revoluble position by any suitable nut or locking pin. Just below the
outer periphery of the plate is a series of rollers r, one of which is shown in
Figure 1 by breaking away a portion of the plate B, and on which the weight
of the davit rests. The locking bolt is adapted to engage with corresponding
openings in plate B, thereby securely locking the davit in any desired position.
In cases where it is imperative to clear the deck of outreaching members, as
for instance when it is desired to dock the ship, or in case the davit is employed
in the navy where several boats are positioned on the deck abreast of each other,
the bolt can be drawn out, and the entire davit swung around until all the
overhanging parts are directly over the deck.
In order to prevent the boat chocks from interfering in the least with the rapid
lowering of the boat, I have provided the outer half M with hinges as shown,
and connected opposite checks with the arms y y¹ and member Y, which permit
the hinged parts being folded down in unison.
In order to strengthen the crane C, I have provided the braces
bolted at their lower ends to the plate c.
which are
I will now explain the construction and operation of the detaching-hook
mentioned above and shown in Figures 2 and 3.
The main portion N of the hook is formed with opposite legs 1 and 2, and is so
'built up with opposite plates 3 31 as to form a groove reaching upward to the dotted
line 4. To the portion N, at a point near the meeting of the legs 1 and 2, is
pivoted the swinging pawl 5, while the lower extremity of the leg 2 pivotally
bears the curved bar 6. The outer extremity of this bar G in turn bears pivotally
a secondary bar 7 which is provided terminally with a cross piece 8. This cross
piece 8 is adapted to rest in the side walls of a cut-out portion 9 formed in the
leg 1. It is evident that as the hook falls and an upward pressure is exerted at
the point of union of the bars 6 and 7 the latter will be forced out of the cut-out
portion 9 and into the position shown in dotted lines in Figure 2 thereby allow-
ing the ring g to fall with the boat. In case the bars 6 and 7 do not come against
anything to release them when lowered the wire guys f f' force the ring 9 up-
ward, the latter will force the pawl 5 into the position shown in broken lines in
Figure 2, and the bar 7 outward thereby releasing the ring g. The pin 10 is to
lock bar when desired.
In the modification shown in Figure 6 instead of the entire device being

page_text: revoluble on the deck, the plate 13' is bolted securely to the deck and the crane C
is capable of swinging loosely in the projection b. Now in order to accomplish
this the pin must first be removed and the lower end of the beam H detached
from the lever K, which latter I have substituted for the segmental gears and
pinions shown in Figure 1. In order to permit this swinging of the crane C
it is necessary to construct the braces free from plate e but permit their lower
ends to rest and slide against the plate c.
The davit shown in the modification can be readily held in place by suitable guy
ropes leading from the projection (d).
I have described the best form of construction now used by me; but it will
be understood that I intend to cover mechanical equivalents when such are sub-
stituted.
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-In combination with a suitable support, an outreaching beam supported by
said support, a secondary beam guided in a projection on said former beam, said
secondary beam being capable of advancement beyond or retraction from a per-
pendicular line from the outer extremity of said former beam, as set forth.
2-In combination with a suitable support, an outreaching beam supported by
said support, a secondary beam held by said support and capable of advancement
toward or retraction from the outer extremity of said former beam, for the purpose
set forth.
3-In combination with a suitable support, an outreaching beam supported by
said support, a secondary beam held by said support and below said former beam.
and means for advancing or retracting said secondary beam toward or from the
outer extremity of said former beam, as set forth.
4-In combination with a suitable support, an outreaching beam carried by
said support, a secondary beam held by said support and below said former bean,
and means for advancing or retracting said secondary beam towards or from the
outer extremity of said former beam, said support being capable of revolution,
as set forth.
5 A detaching hook for davits provided with opposite legs, a bar pivoted to
one of said legs and pivotally bearing a secondary bar, a cut-out portion on said
opposite leg into which said secondary bar detachably engages, and a pivoted
pawl between said legs, and adapted to disengage said secondary bar from said
cut-out portion, for the purpose set forth.
Dated this Twenty-seventh day of Januaru 1909