US2635259A

US2635259A - Launching gear for boats

Info

Publication number: US2635259A
Application number: US3346A
Authority: US
Inventors: Morley William Edward; Moore Walter Gordon; Rouse William Cameron
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-01-27
Filing date: 1948-01-20
Publication date: 1953-04-21
Anticipated expiration: 1970-04-21

Description

W. E. MORLEY ETAL LAUNCHING GEAR FOR BOATS April 21,1953

3 Sheets-Sheet l Filed Jan. 20, 1948 April 21, 1953 w. E. MORLEY ETAL 2,635,259

LAUNCHING GEAR FOR 'BOATS Filed Jan. 20, 1948 3 Sheets-Sheet 5 y W. Allo/nay Patented Apr. 2l, 1953 LAUNCHING GEAR FORBOAT William Edward Morley, Gillingham, Walter Gordon Moore, Brkdale, and William Cameron Rouse, Liverpool, England applicati@ January zo, 194s, serialN. 3,346 In Great Britain January 27, 1947 1 claim. 1

This invention is for improvements in or relating to launching and lower gear (e. g. lowering gear for ships lifeboats) of the gravity-operated type comprising a davit arm or the like and a stand and having a multiple pivot arrangement for the davit arm (i. e. of the type in which there are at least two pivots about which the davit armswings outboard successively). Such launching or lowering gear is hereinafter referred to as a davitof the type specied.

One object of thepresent invention is to provide a davit or the like of the type specied, in which movement of the davit arm is checked or guided so that the davit head or horn follows a relatively smooth path. In other words. an object of the present invention is to smooth out the step or steps, and thereby the abrupt changes of load which occur in multiple pivot davits as the arm changes from one pivot to another.

Accordingly the present invention provides a gravity davit of the type specified and having, at least, two pivots about which the davit arm pivots outboard successively, characterised by guide means acting on the davit arm to guide it out of trulyeircular movement about, at least, the rst of said pivots and reduce the curvature of the path of movement of the davit arm head to less than what it would have been had the davit arm movement been truly circular about said rst pivot, whereby there is a smoothing-out of the movement of the davit arm head as the pivotal support for the arm changes from one pivot to the next. In other words, the sudden changes of direction and load which occur where the arc of movement about one pivot intercepts the arc of movement about another are smoothed out at least to a material extent. Thus, there is a substantially steady load on the wire of the control winch or other gear instead of a sharp change of load at the point of engagement of each succeeding pivot.

In a preferred embodiment of the invention a roller on the davit arm engages a guideway or track on the stand or vice versa.

The invention will be further described, by way of example, with reference to the accompanying diagrammatic drawings which show one embodiment of the invention as applied to a gravity davit of the multiple pivot type. On the drawings:

Figure 1 is a side elevation of the davit,

Figure 2 is a front elevation, and

Figure 3 is a fragmentary detail view of the guide means for the davit arm.

Briefly, the davit shown on the drawings comprises a stand I0. a davit arm II and a link I2.

2 .l One end of the link I2 is pivoted to the stand I0 at I3 (to provide a iirst or upper fulcrum or pivoting device for the arm) and the otherend of the link is pivoted to the davit arm at I4 (to provide a second or lower fulcrum or pivoting device for the arm). The arm II carries a keel chock or rest I5 which provides support for the boat b in the stowed position. A stop'IS on the davit stand I0 arrests downward and inboard movement of the link I2 at the end `of movement of the davit arm and link aboutthe rst fulcrum I3. A further stop-plate II halts outboard movement of the davit arm, about the fulcrum I4, at the final extended position of the arm. The davit stand comprises two cheekplates secured together in spaced-apart relationship and housing the davit arm between them so as to provide good lateral support for the arm.

For the purpose of the present invention it is convenient to provide the lower forward part of the davit stand with an inclined or curved trackway or guide I8 and the davit arm with a roller I9 which is journalled on a horizontal axle 20 on the arm in the neighbourhood of the keel f rest I5. In the launching operation, as the arm II and link I2 tilt about the rst pivot I3 the roller I9 engages with the trackway I8 and constrains the arm to move so that the path of movement of the davit head I Ia is dened by the guideway I8 and not solely by the angular or circular movement of the link I2 about the pivot I3. The inclination and length of the guideway I8 is such that there is no sudden dip and abrupt change of load as movement of the davit arm changes from that taking place about the first pivot I3 to that taking place about the second or subsequent pivot I4. It will be noted that the inclination of the track I8 to the horizontal is less than that of the link I2 when the latter is in its lowermost position. The roller may leave the trackway some time before the arm completes its full outboard movement. Successive positions of the roller I9 as it moves from the stowed position indicated at A to the fully outboard position indicated at E are indicated at B, C and D and the corresponding positions of the davit head IIa and second fulcrum I4 are similarly marked. The approximate path of movement of the davit head is indicated by the line F. The line G indicates the truly circular path of movement of the davit head if the `track I8 and roller` 20 are omitted and it will be noted that there is an adverse sudden change of direction at G. I.

To ensure outboard movement of the davit arm, even when the vessel on which the davit It will be appreciated that anlobv'ious mechanical equivalent of the above described aring the inboard portion of its movement by the swinging of said link about said pivot means relative to 4and outboard of said stop means and during the outboard portion of its movement by pivoting relative to said link while said link is lstationary against said stop :"mearis, 'a 'roller on fsaid davit 'arm -`'and engageable with said track- Way to support said arm during the inboard por- -tion of its movement and while said'link is spaced rangement would be to have a roller 'or the "like on the stand arranged to engage a 'cam-Sprole or track on the davit arm to constrain the headV of the latter to move in the required path.

In the stowed position the davit arm iii-lay rest directly or indirectly on the upper face of Y the link I2 or on the upper pivot I3.

We claim:

,A gravity davit 'comprisinga davit stand having -a vdcwnwardly A:and outwardly 'extending tramway, 'iixed 'pivot means at the upper 'portion lof said stand, a link pivotally suspended 'rom' said pivot `means, Aa davit arm "having a yd'avit head yat one fend 'and being pivoted at the other'end to the :lower free fend 'of said link, stop lmeans 7at the nlower portion or Asaid 'stand b'e'lowa'nd-o'i`1tb'c iard'of said pivot means "to limit iIibda'rd 'swinging df 'said link to Ja 'position extending downwardly and outboard irom said p'ivot means, said davit arm vbeing 'movable between "a lstowed Iinboard Yposition and 'an extended 'outboard position vand vbeing guided dur- 'from said stop means, whereby tracking of said lrlleronnsaid trackvvay causes smooth translational movement. of-said arm during the swinging"6f"saidlink'rlative to said stop means and guides .the davithead in a smooth path that is tangent tothe arc about the pivot between the *davit farm and lin-ll: when the link is stationary against saidfstop means.

WILLIAM EDWARD MORLEY. WALTER *GORDON MOORE.

lGreat Britain Sept. .19.1922'17