US2221835A - Winch - Google Patents

Description

7 1940- c. L. HARKRADER 2,221,835

WINCH Filed June 10, 1939 3 Sheets-Sheet 1 1N VENT OR.

[Li] 'A" a C'ar 01 g? *ATTORLA Nov. 19, 1940. c. L. HARKRADER WINCH Filed June 10, 1939 I 5 Sheets-Sheet 2 INVENTOR.

Nov. 19, 1940. c. HARKRADER WINCH Filed June 10, 1939 3 Sheets-Sheet 3 wil m m Q MW W mawo w n r 2. L W C R hm w mm mm L w w v k.

Patented Nov. 19, 1940 UNITED STATES p rmlrtmt 1 Claim.

This invention relates to a new and usefulimprovement in winches, particularly those employed in the highly specialized and exacting duty.

of raising and lowering life-boats hung on ships davits. A winch forthispurposemustbe absolutely dependable, and, because of the almost inevitable failure of power in case of ship-wreck, must provide for the safe loweringof thelife-boat independently of the motor. Also, means must be provided to insure that during the raising of the life-boat, it cannot drop in case of failure of power for any reason, or through incorrect or careless operation.

A winch having these characteristics is obtained by this invention, one form of which is shown in the accompanying drawings, of which- Figure 1 is a view in perspective of the winch;

Figure 2 is a side elevation;

Figure 3 is a view, partly in section, of the 3;) mechanism of the winch; and

Figures 4 and 5 are detail views of the overrunning clutch incorporated in the mechanism.

As shown, the winch consists of a housing I, on which is mounted a motor 2. To the lower 9.5 end of shaft 3 ofmotor 2, is attachedthe eX- pandible element 4 of a centrifugal clutch 5, the other element of which a cylindrical drum 6 mounted upon, or attached to,shaft 1 extending below and in alinement with motor shaft'3. so Normally, the expandible or braking'elements 4 of centrifugal clutch 5 are automatically held in retracted position 'as shown in Figure 3, out of engagement with drum 6 by springs 8.

On the lower end of shaft 1 is mounted a 3.", beveled pinion 9 which meshes with a beveled gear ID keyed to a horizontal shaft ll. Shaft II also carries a worm I2, which meshes with a worm-wheel l3 keyed to a shaft I4. Shaft M is also provided with a pinion l5, which meshes with two identical gears l6 and I! connected, re-

spectively, to identical winding drums 20 and 2|, respectively, which are preferably positioned one above the other to save deck space.

When the life-boat is to be raised, motor 2 is 43 started, and when it has gained sufiicient speed,

shoes 4 of centrifugal clutch 5 will move outwardly to engage drum 6 of the centrifugal clutch, so that the power of the motor is transmitted through the beveled gears 9 and I!) to shaft ll, 5:} and from this shaft to the winding drums 20 and 2! through worm l2, worm-wheel l3, shaft [4, pinion I5 and gears 16 and H. The fall 22 from one of the pair of davits for a life-boat is conneoted to the end of the usual spirally grooved 55 surface of the upper winding drum 2U, andthe (or 254,185) r dtheriall 23 is similarly connected to the lower winding drum 2 l and is given one or more turns around that drum, so that its position on the drum is slightly in advance of that of the other fall upon the upper drum. Therefore, since both drums'turn in the same direction at the same speed,the' upper drum 20 can be utilized as a guidefor fall 23 which passes over it on its way to lower drum 2|, "In this way both falls can enterthe housing through a relatively narrow opening 23a. at the top of the housing, or, in other words, at the maximum height down the deck.

Since both winding drums are identical, and since both gears l6 and H are also identical and in'constant mesh with pinion l5, they can only rotate together, in the same direction and at exactly the same rate of speed, so that both falls will be wound in, or payed out, simultaneously and'at exactly the same speed, from which it follows'that the life-boat will be positively main tained in a horizontal position. As -apositive safe-guard against the accidental dropping of the life-boat while it is being hoisted, through'accidental or other failure of motor 2, a brake 2a is associated with shaft II. This brake gz, consists of a brake-drum 25 rotatably mounted upon-shaft I! and 'a' surrounding brake-band 2B normally 'maintained in sufiicient engagement with brake-drum 25 to prevent the brake-drum from turning under the load of a life-boat by means'of a weightedarm 21; Brake-drum 25'is connected to shaft H by an over-running clutch 28 (Figs. 3, 4 and 5), which permits shaft H to turn in the winding-in direction independently of brake-drum 25, but not in the other direction. 5 Therefore, while a life-boat is being hoisted, brake 24 may remain fully set at all times without interfering with the hoisting as a positive protection against the accidental dropping of the lifeboat.

The over-running clutch between shaft II and brake-drum 25 may be of any desired type, that shown having proved entirely satisfactory. The form shown consists of a sleeve 29, keyed to shaft H and provided with recesses for the reception of pins 30 spaced degrees apart, which are urged towards the brake-drum 25 by springs 3|. The end of the hub of brake-drum 25 adjacent the ends of pins 36 is provided with a ratchet 32 having a pair of teeth 33 spaced apart turning of shaft H in the other or paying-out direction, provided brake 24 is set, through the engagement of pins 30 with the teeth 33 of ratchet 32. Thus brake 24 afiords positive assurance against accidental dropping of the life-boat at all times while it is being hoisted.

Whenever the motor is idle it is disconnected from the winch through the automatic operation of centrifugal clutch 5, so that the lowering of the life-boat is effected by simply releasing brake 24 to the desired degree by manually lifting weighted arm 21. This permits shaft II to turn in the lowering away direction under the control of brake 24. Consequently, the winding drums 20 and 2i will pay-out the falls at the rate determined by the degree to which brake 24 is released. Thus, the speed of lowering the lifeboat is controllable by the manual manipulation of brake 24 through arm 21.

Since the manual manipulation of brake 24 injects another possibility of accident through human fallibility, a further safe-guard against too rapid lowering away is provided in the form of another centrifugal clutch 34, which may conveniently be associated with the end of shaft H opposed to brake 24. This clutch may be similar to centrifugal clutch 5, which serves as a means for connecting the motor to the winch and may be of any desired type. As shown, it consists essentially of brake-shoes 35, expandibly mounted upon a hub 36 keyed to shaft II and engageable, when expanded, with a cylindrical brakedrum 3'! aifixed to winch housing I. Expandible shoes 35 of centrifugal clutch 34 are normally held out of engagement with brake-drum 31 by springs 38 so that centrifugal clutch 34 will not interfere with the winding in or lowering away of the falls unless the speed of rotation of shaft ll exceeds the predetermined amount. HOW- ever, if the boat is lowered too rapidly, through accident or the mishandling of hand-brake 24, centrifugal clutch 34 will operate to slow down the speed of rotation of shaft II, and, consequently, the speed of lowering away of the lifeboat, to the predetermined rate.

All parts of this winch may obviously be of very sturdy construction so that, barring breakage of the falls themselves, it is impossible for any untoward accident to befall the life-boat when being hoisted or lowered. Also complete and very delicate control over the life-boat is maintained, particularly of lowering, through the combined agencies of the overrunning clutch 28, manually-operated brake 24, and centrifugal clutch 34. In an emergency, life-boats may be safely lowered even by comparatively inexperienced persons, by means of this winch. Also, as shown in Figures 1 and 2, the winch is very compact, requires a minimum of deck space and may be very thoroughly protected from the weather, the only opening being that at the top of the housing through which the falls pass en route from the davits to the winding drums.

It will be understood that the winch described above may be modified in many respects without exceeding the scope of this invention.

I claim:

A! ship winch for raising and lowering life boats, which includes two identical winding drums, one above the other, each of which is adapted to wind in or pay out a fall of a life boat davit, said upper drum also constituting a sheave or guide for a fall in its passage from the davit to the lower drum, a shaft, gearing between said shaft and said drums for turning said drums in the same direction simultaneously and at identical speeds, an electric motor for turning said drums in winding-in direction through said gearing, said motor normally being operatively disconnected from said drums a centrifugal clutch between said motor and said shaft for automatically connecting them so as to turn said shaft and said drums in winding-in direction when said motor exceeds a predetermined speed and to maintain said operative connection until the speed of said motor falls below said predetermined speed, a brake-drum loosely mounted on said shaft, a brake-band normally engaging said brake drum to prevent rotation thereof, an over running clutch, one element of which is fixed to said brake-drum and the other element to said shaft and so arranged as to permit rotation of said shaft in the other direction when said brake is set, said brake-band being manually releasable from said brake-drum to any desired degree for controlling the rate of rotation of said shaft in paying out direction when said motor is inoperative and a centrifugal brake associated with said shaft for automatically limiting the speed of rotation of said shaft in paying out direction to a predetermined speed independently of said other brake.

CARL L. HARKRADER.

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