US1893157A - Crane structure - Google Patents

Description

Jan. 3, 1933. c. BURRILL ET AL CRANE STRUCTURE Filed May 21, 1952 2 SheetsSheet l M w m m \l W? fi- EQWMQ m A mH- i @4 m M ir 1 G n n w m & 3 mm 3 m w a rc 5 9 2 ATTORN E75 Jan. 3, 1933. c. BURRILL ET AL 1,393,157

CRANE STRUCTURE Filed May 21, 1932 2 Sheets-Sheet 2 Patented Jan. 3, 1933 UNHTED STATES FATENT 0FFE OF WALLSEND-UPON-TYNE ENGLAND, 1943M 1.

" 33 TO THE OETIEEUM DAVIT COM- PA'NY LIMITED, OF VIALLSEI- D-UPON-TZIIE, ENGLAND, A BRITISH. COMPANY CRANE ST BUOTURE Application filed May 21, 1932, Serial No. 612,768, and in Great Britain May 30, 1931.

This invention relates to improvements in crane structures, and is especially directed to crane structures which comprise a rigid strut pivotally anchored at its lower end and having a rocking jib eccentrically pivoted at its upper end, the load be'ng suspended from the end of the longer arm of said jib.

The object or this invention is to provide an improved crane structure for general purposes, and a further object of the invention is to provide a light and inexpensive con-- struction for use n duplicate as a boat crane or davit for launching and picking up a ships boat, for launching and picking up hydroplane, or for analogous operations.

Another object of the invention is to provide a crane structure having power, uue to the balancing property of its weight, to lift the end otthe longer arm of the jib a predetermined amount automatically when the load is removed.

Another object of the invention s to provide improved means for swinging the crane structure in a vertical plane about the heel pivot of its strut.

A further object of the invention is to provide improved means for positively lmiting the inward swing of the crane structure.

With these and other objects in view, as will appear from the following description, our invention consists in the novel features of construction, combinations of elements and arrangements or parts hereinafter fully described and set out in the appended claims.

In the accompanying drawings forming part of this specification and in which similar characters of reference denote like and corresponding parts throughout the several views Figure 1 is a side elevation of a crane structure embodying our invention intended for use as a boat davit, the davit being shown in the inboard position Figure 2 is a front elevation of the davit of Fig. 1

Figure 3 is a sectional elevation to a larger scale of a portion of the actuating means of the davit of Figs. 1 and 2;

Figure 1 is a similar view to Fig. 1 showing the davit in an outboard position;

Figures 5 and 6 are similar views to Figs. 1 and 4 respectively illustrating an alternative construction; and

Figures 7 and 8 are similar views to Figs. 1 and 4 respectively illustrating another alternative construct-ion.

Referring more particularly to the specific form of the invention disclosed in Figs. 1 to l of the accompanying drawings, 10 is a strut comprising an H-section girder to the ends of which are riveted a heel. fitting 11 and a top fitting 12. The heel fitting 11 is formed with a keel support 13 and lugs 1st through which are passed aligned horizontal pivots 15 journalled in a double bearing 56 firmly attached to the ships deck 16, said pivots being disposed parallel with the side 17 or" the vessel. The top fitting 12 is formed with a lug 18 through which is passed a hori- Zontal pivot 19 on which are mounted spaced parallel plates 20 which form the rocking jib, the jib pivot 19 being parallel to the heel pivots 15. The outboard arm 21 of the jib is longer than its inboard arm The end o1 the boat 23 adjacent to the davitis suspended by a hook 21 from a pulley block 25, and the rope 26 for lowering and raising the boat is attached at 27 to said pulley block, and, after passing therearound, is passed around a pulley block 28 on a pin 29 between the outboard ends of the jib plates 20, around a. pulley 30 on the jib pivot 19, and around a pulley 31 carried by a cast bracket 32 firmly secured to the deck 1 behind the heel pivts 15, and is then led between iairleads 33 to a convenient bollard or a hand or power winch which, being the usual practice, we have not illustrated.

'1. he actuating member comprises a threaded shaft 34 adapted to he travelled into and out of a sheath 85 the upper end of which is attached to a pivot 36 at the inboard end of the jib 20. As shown best in Fig. 3, the lower end of the sheath is fitted internally with a nut 37 which engages the threaded shaft 34; and is held stationary therein by dowels 38. The lower end of the shaft 34: is keyed to a worm wheel 39 mounted within a carrier 40 formed with lugs 11 engaging a pivot 42 j ournalled in the upper end of the bracket 32 which forms a stationary anchorage tor the actuating member. The worm wheel 39 is revolved by a worm 43 the shaft 44 of which is journalled in the carrier 40 and is fitted with a crank handle 45. Byrevolving the handle 45 the Worm 43 is caused to revolve the worm wheel 39 and hence the shaft 8% which travels through the nut 37 in the sheath and, according to the direction of rotation, length ens or shortens the actuating member, the effect being to swing the strut 1O outboard or inboard about its heel pivots 15. The sheath 35 is char ed with lubricant, the lower end of the nut 37 being cupped at 46 to fit snugly against t is carrier 10 against which it abuts when the davit is in its inboard position.

The means for controlling the rocking motion of the jib 20 as the strut 10 is swung outboard and inboard comprise a pair of tension rods 47 the upper ends of which engage the pivot 36 at the inboard end of the jib. The lower ends-oi the tension rods are formed with elongated eyes 48 which engage pivots 4:9 projecting from the sides of the bracket 32 about midway between the heel pivots 15 and the pivot 42 of the carrier 40 of the actuating member. The elongated eyes 4:?) allow or a limited lengthwise move ment of the rods? about their anchorages 1i i i In the inboard position, the strut 10 has an angle of about 60 to the deck 16. 50 is a i wood chock attached to the face or the strut against which the side of the boat 23 bears when the strut is 1nboard. The keel 51 of the boat is received in the keel supports 13 on the heel fittin s 11 as shown in Pi 1.

Rope gripes 52 are slung around the boat to retain it in its inboard position, one end of each gripe being attached at to the keel support 13 and the other end being detachably connected by slip release gear o-lvto the bracket 32.

It will be understood that the davit is duplicated, one davit being provided near each end of the boat. The davit-s stow directly behind the hooks 24- by which the boat is sus pended, and the two davits are contained within the length of the boat. On the gripes 52 being removed and the handles do of the two davits being simultaneously operated to extend the actuating member 34, 35, the struts 10 with their rocking jibs 20 are swung outboard as shown in Fig. l. The length and anchorages of the tension rods 47 are chosen so that the initial outboard movement of the pulleys 28 carrying the boat falls 6 is slightly upward as indicated by the dotand-dash line 55 in Fig. 1, and the keel 51 of the boat is raised clear of its supports 13 by the tension rods 47 which also take the load off the actuating member 36 35. The outboard travel of the struts is continued until there is a suitable'clearance between the boat 23 and the ships side 17, and the boat is then trolled by a single handle l5 which isdisposed at a'convenient height, and no manipulation 01"" the boat falls 26 is necessary until theboat is at the required distance from the side of the ship. The shipsboats can be disposed end to end near the side of the deck, and the necessary stowage area. minimized. The height of the davit'is small, and it can be arranged to operate between decks. The bcatcarrying capacity of the ship can thus be increased, or free open deck spaces can be obtained on the top deck. Where some or all of the boats are stowed in a tween deck, they are protected from the weather, and the wind resistance of a vessel is by this or; pedient considerably reduced. Alternative ly, with davits of normal height, greater side clearance than is at p esent available can be obtained. the upper blocks 28 are arranged wit iin the platesQO of the jib, danger of a toppling block is avoided, and any tendency of the upper block to twist in relation to the lower block is reduced. As the range of stress in the actuating member S l, varies from compression in the inboard position shown in Fig. l to tension in the outboard position shown in Fig. 4:, the weight of the davit structure can be materially reduced. The davit works equally well whether on the higher side or on the lower side, the ship has a list. i V

A nov'elfeature of our improved davit is its power, due to the balancing property of the weight of its structure, to lift the outboard end 29 of the ,jib a predetermined amount automatically when the load is removed.

Our invention is peculiarly applicable to cranes suitable for launching and picki up from the sea hydroplanes and for other general purposes. For thesepurposes, the crane may be arranged to operate as a single unit or in pairs as desired, and may be mounted on a platform rotatableabout a pivot so that the structure can be rotated, or alter natively the platform may be mounted on straight or curved runways.

When the structure is used a crane and the actuating member is arranged to work in.

tension only, a wire rope may be iitted in place of the sheath 35 and threaded shaft 3%- above described, said rope being lengthened and shortened as required by means of a winch or equivalent device operated by power or by han v r Inthe modified construction illustrated in Figs. 5 and 6, the tension rod 47 is dispensed with and in its place a wedge-shaped chock 57 is attached to the underside of the jib 20. The chock is so arranged that it abuts against the upper part of the strut 10 as shown in F 5 when tie jib is in its inboard position and limits the inboard travel of the structure without affecting its freedom to move outboard. Instead of the chock 57, short length of wire 58 may be attached between the strut 10 and the inboard end 22 of the ib as shown in Figs. 7 and 8. These arrangements are especially suitable for cranes.

In another alternative method of applying our invention and as illustrated in Figs. 5 and 6, the actuating member comprises a rack 59 travelled by a pinion 60 in place of the sheath 35 and threaded shaft 3d above described, the rack being retained in engagement with the pinion by a carrier 410 pivoted on the spindle of the pinion which is mounted in bearings in the bracket 32. The pinion is rotated by a handle 61 on its spindle.

In a further alternative method at apply ing our invention and as illustrated in F '7 and 8, the actuating member is attached to the inner arm 22 of the rocking jib as described above and comprises a tension rod 62 pivoted at 63 to a crank 64: operated by hand through pinion gear 65 mounted on the bracket 32 and rotated by a handle 66 or by ower.

l/Vhile we have described what we new con sider to be the preferred embodiment of our invention and several modifications, we wish it to be understood that these disclosures are by way of example, and that various changes or modifications of a more or less minor character may be made in the actual crane structure from those herein disclosed and described without departing from the spirit of our invention. We therefore claim all such structures as may be said to fall fairly within th scope of the following claims.

lVhat we claim as our invention and de sire to secure by Letters Patentis 1. In a crane structure comprisin a support, astrut pivoted at its foot to said support, a rocking jib eccentrically pivoted at the head of said strut and means for suspending the load from the longer arm of said ib, the combination of an actuating member pivotally attached between the end of the shorter arm of said jib and an anchorage on said support, means for lengthening and shortening said actuating member, and means for con trolling said jib.

2. In a crane structure comprising a support, a strut pivoted at its foot to said support, a rocking jib eccentrically pivoted at the head of said strut and means for suspending the load from the longer arm of said jib, the combination of an actuating member pivotally attached between the end of the shorter arm of said jib and an anchorage on said support, means for lengthening and shortening said actuating member, and means for controlling said jib, said control means comprising a stop operating between the jib and the strut.

S. l'n a crane structure comprising a support, a strut pivoted at its foot to said sup port, a rocking jib eccentrically pivoted at the head of said strut and means for suspending the load from the longer arm of said jib, the combination of an actuating member pivotally attached between the end of the shorter arm of said jib and an anchorage on said support, means for lengthening and shortening said actuating member, and means for controlling said jib, said control means comprising a connection pivotally attached between the end of the shorter arm of said jib and an anchorage on said support intermediate of the heel pivot of the strut and the anchorage of the actuating member.

l. In a crane structure comprising a support, a strut pivoted at its foot to said suppcrt, a rocking jib eccentrically pivotec a the head of said strut and means for suspending the load from the longer arm of said jib, the combination of an actuating member piveta attached between the end of the shorter arm of said jib and an anchorage on said support, said actuating member comprising a sheath, a nut mounted on said sheath, a threaded shaft engaging said nut, means for producing relative rotation between said shaft and said nut to lengthen and shorten said actuating ineinl er, and means for controlling said jib, said control means comprising a connection pivotally attached between the end of the shorter arm of said jib and an anchorage on said support intermediate of the heel pivot of the strut and the anchorage c-f the actuating member.

5. In a crane structure comprising a support, a strut pivoted at its foot to said support, a rocking jib eccentrically pivoted at the head of said strut and means for suspending the load. from the longer arm of said jib, the combination of an actuating member comprising a sheath the upper end of which is pivotally attached to the end of the shorter arm of said jib, a nut fixed in the lower end of said sheath, a threaded shaft engaging said nut, a bracket on said support, a carrier pivotally mounted on said. bracket and form ing an anchorage for s i l shaft, means mounted in said carrier for rotating said shaft to lengthen and shorten said actuating member, and means for controlling said jib, said control means comprising a connection pivotally attached between the end of the shorter arm of said jib and an anchorage on said support intermediate of the heel pivot of the strut and the anchorage of the actuating member.

6. In acrane structure for use as a ships davit comprising a support, a strut pivoted at its foot to said support, a rocking jib eccentrically pivoted at the head of said strut and means for suspending the boat from the longer arm of said jib, the combination of a heel fitting on said strut, a support for the boats keel on said heel fitting, a chock'for said boat on the outboard face of said strut, detachable gripes for securing said boat against said strut, an actuating member comprising a sheath the upper end of which is pivotally attached to the end of the shorter arm of said jib, a nut fixed in the lower end of said sheath, a threaded shaft engaging said nut, a bracket on said support, a carrier 'pivotally mounted on said bracket and forming an anchorage for said shaft, means mounted in said carrier for rotating said shaft to lengthen and shorten said actuating member, and means for controlling said jib, said control means comprising a connection pivotally attach ed between the end of the shorter arm or" said jib and an anchorage on said support intermediate of the heel pivot of'the strut and the anchorage of the actuating member.

7. In a crane structure for use as a ships 'davit comprising a support, a strut pivoted at its foot to said support, a rocking jib eccentricaily pivoted at the head of said strut and means for suspending the boat from the long er arm of said jib, the combination of a heel fitting on said. strut, a support for the boats keel on said heel fitting, a chock for said boat on the outboard face of said strut, detachable gripes for securing said boat against said strut, an actuating member comprising a sheath the upper end of which is pivotally attached to the end of the shorter arm of said jib, a nut fixed in the lower end of said sheath,

a threaded shaft engaging said nut, a bracket on said support, a carrier p'ivotally mounted on said bracket and forming an anchorage for said shaft, means mounted in said carrier for rotating said shaft to lengthen and shorten said actuating member, and means for controllin said jib, said control means comprising tension rods pivotally attached to the end of the shorter arm of said jib, elongated eyes at the lower ends of said rods, said eyes en- 'aging anchorages on said support between the heel pivot of the strut and the anchorage of the actuating member.

In testimony whereof, we affix our signatures.

LENNARD CONSTANTINE BURRILL. HARRY BOCLER. NORMAN MACLEOD HUNTER.

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