US2523878A - Hoist mechanism - Google Patents

Description

Sept. 26, 1950 F. I. RATAICZAK 2,523,878

nozsw MECHANISM Filed March 12, 1945 2 Sheets-Sheet 1 g o 1 l J NIfENTO (g/MW Sept. 26, 1950 F. L-RATAICZAKY I 8 HOIST MECHANISM Filed March 12, 1945 2 Sheet s-Sheet 2 Patented Sept. 26. 1950 UNITED STATES PATENT OFFICE ncrsr figziimsn Francis I; Rataiczak, Dayton,- Ohio,v assignor to General Motors 'Qorporation, Daytom Ohio, a-

corporation of Delaware Application Ma'rch12, 1945, Serial No. 582,215

' (o1. an -9i) Claims. 1

This invention relates to hoist mechanism and moreparticularly to an improved gun turret hoist for use in airplanes.

It is an object of this invention to provide a simple, compact and dependable hoist mechanism which may be used for hoisting gun turrets and the like.

It is-afurther object ofthi's invention to provide amanually operated hoist which is easy to oper ate and which is capable of lifting substantial loads. 4

Another object of this-invention is to provide improved safety/mechanism for preventing too rapid lowering of the load.

Another object of this invention is to provide a safety device which automatically stops the lowering operation upon release of the operating handle by the operator.

More particularly, it is an object of this invention to provide a manually operated hoist in which a brake mechanism is used for preventing too rapid lowering of the load and in which an over running clutch is provided for rendering the brake ineffective when raising the load.

Further objects and advantages of the present invention-will be apparent from the following de scription, reference being had to the accompanyingdrawings; wherein a preferred formof the present invention is clearly showm In the drawings:

1 is a pictorial view showing the hoist mechanism; 1

Fig; 2 is a fragmentary sectional view (with parts broken away) takensubs'tantlally on line 2 -2 of- Fig, 3; V Fig. 3 is a sectional view taken on line 3 -3 of Fig. 2

V Fig": 4 is a sectional View taken online 4"-4 of Fig'. 3i and Fig. 5 isla fragmentary sectional view showing agear lock. l

The hoist illustrated in the drawings was designed for raising and lowering a gun turret on an airplane, but it is obvious that hoists of the type shown may be used for other purposes equally well.-

Referrin'g' now to the drawings wherein I have shown a preferred embodiment of my improved hoist mechanism, reference numeral l0 desig-' n'ates a stationary top support from which the hoist mechanism is suspended by means of sus pensionrods l2 and suspension cables 14. The support l0 may be any suitable support and in the case of an airplane would be a part of the fuselegs of the plane. Reference numerals l6" and I8 designate stationary mounting plates betweenwhich the gear housing 20' is mounted as shown. Reference numeral 22 designates generally the movable portion of the hoist to which the load is secured. Thus when the hoist is used for raising and lowering a gun turret; the gun turret is attached directly to the movable portio 22 of the hoist. The guide rods 24 are attached to the movable portion 22 and serve as guide means for the portion 22 as it moves up and down. The rods 24 are slidably supported within bushings 28 carried by the plate 16 as shown. The upper ends of the rods 24 are bolted to the guide plate 28 which is supported for sliding engagement with the rods i2 and the central cylindrical housing 30. a

Referring now to Figs. 2 and 3 of the drawings wherein I have shown the gear mechanism for operating the hoist, reference numeral 4!] desig hates the handle or crank which is secured to the crank shaft 4'2 and disc 44 by means of a pin 46 arranged as shown in Fig. 3. The shaft 42 has a pinion 48 keyed thereto adjacent the inner end of the shaft which is arranged in meshing en'- gagem'ent with a larger gear 50. The gear 50 is keyed to the shaft 52 to which a pinion 54 is also keyed. The pinion 54 is arranged in driving engagement with a larger gear 55 which in turn is keyed to the extension 58 provided on a pinion gear 60. The pinion B0 is rotatably supported on the shaft 62 and is drivingly connected to a pair of gears 64 and 66 (see Fig. 2) which in turn are drivingly connected to the reciprocating: rack 68'. The shafts 42, v 52 and 62 are suitably journalled in the complementary gear housing sections 10 and 12.

The reciprocating rack 68 is provided with a reduced lower end portion 16- which is threaded to receive the nut l8. The nut 13 secures the mov able carriage or load supporting. means 22 to the rack 68. The rack 68 is of semi-circular crosssection and is slidably supported within the stationary cylindrical housing 30 which in turn is secured to the main support I 0 and the plates l6 and I3. Inasmuch as a gun turret hoist must be capable of raising and lowering a gun turret which when fully equipped weighs in theneign bo'rhocd of one ton. it is" a parent that a large amount of force must be transmitted from the handle 40 to the rack 68 by the interposed gears. By virtue of using a pair of gears 64 and 66 for transmitting power from the gear to the rack 68, the load on the individual teeth on the gears 69, 64, Stand 68 has been reduced.

A novel brake and brake release mechanism has 3 been provided for holding the load in any desired position and for preventing the hoist from lowering the gun turret when one lets go of the handie 40. The brake shoe mechanism comprises a pair of brake shoes IIiII which are pivotally supported on the end plate I2 of the gear housing by means of suitable studs I84 arranged as shown. The brake shoes I88 are provided with suitable brake lining material I05 which is arranged to frictionally engage the cylindrical brake drum I88 which is drivingly connected to the shaft 42 through an overrunning clutch. The overrunning clutch comprises the clutch plate 41 keyed to the shaft 62 and a plurality of frictional rollers IIE! which are arranged to engage the internal surface H2 of the brake drum I88 when the handle is rotated in a direction so as to lower the hoist. As shown in Fig. 4, the frictional rollers II?) are biased into frictional engagement with the internal surface II2 by the spring pressed plungers II l. Each plunger M4 is slidably supported in a hole I I6 provided in the clutch plate d i. A spring H8 is provided for each plunger for eldin -the plunger outwardlyl The arrangement of the overrunning clutch is such that the brake'drum 5G8 revolves with theshaft 32 at all times upon rotation of the handle in the direction for lowering the load but does not rotatewiththe shaft 2 upon rotation of the handle in the opposite direction. By virtue of 'the'above described arrangement, it is apparent that the handle may be'rotated so as to elevatethe gun turret even though the brake shoes 68 are in engagement with the brake drum Hi8. It is also apparent that the brake mechanism described hereinabove will hold the gun' turret in any desired degree of elevation.

In'order to lower the turret it is desirable to atleast partially release the brake mechanism. This may be done by swinging the handle to about the pivot 45 in a plane at right angles to the normal plane of rotation of the handle A0. Movement of the handle so in this manner causes the handle projection I 3% to push in on the brake operating plunger 532 slidably carried by the clutch plate 45. The plunger IE2 is provided with a roller I34 at its inner end which cooperates'with the circular groove i355 provided on the cone-shaped earn element I33 which is slidably supported on the shaft 42. ihe cone-shaped clement I38 is arrang d to engage the adjustable studs I40 carried by the brake shoe operating levers I42. The levers M2 are pivoted on pins I44 carried by the end plate '52 of the gear housing; The outer ends I46 of the levers I62 serve as cams for camming the brake shoes I96 into braking engagement with the brake drum I58. The inner end of each lever I42 is connected to one endof a spring Hi8 which has its other end connected to one of the brake shoes I05 in the manner shown. Thus by manipulating the handle All so as to push in on the plunger I32; the cone-shaped ca-m I38 operates the levers I 52 to release the pressure on the brake shoes IEiIl. The brakespreferably are adjusted so as never to become fully disengaged at any time whereby the amount of restraining force which needs be applied to the handle when the load is being lowered is less than otherwise would be required. As pointed out h'ereinabove, the overrunning clutch declutches the brake from the crank shaft 42 when the handle 5 6 is rotated in the direction for raising the turret. As a consequence of the above arrangement, the brake does not interfere with free movement of the hoistduring the raising operation even though the brake at all times restricts the movement of the hoist when the load is being lowered. If desired, the studs I40 may be adjusted to cause the cam I38 to completely disengage the brake shoes I00 from the drum I98.

A gear lock generally designated by the reference numeral I58 (see Fig. 5) has been provided for positively locking the gears against rotation. The gear lock comprises a receiprocating looking plunger I52 which is adapted to engage within an aperture I54 in the gear for positively locking the gear 59 and consequently the rest of the gear train against rotation. A spring I51 biases the plunger Hi2 inwardly at all times and a pin I55 carried by the plunger is provided for holding the plunger outwardly. The pin I55 rests within a deep notch I58 when the gears are locked against rotation and is held within a shallow notch I60 when the plunger is out of locking engagement with the gears. 'While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms mi ht be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. In a hoist mechanism, a crank shaft for said hoist, a support for said crank, shaft, brake shoes pivotally carried by said support, a brake drum surrounding said shaft, a one-way clutch drivingly connecting said brake drum to said shaft, cam means slidably supported on said shaft, complementary cam means for camming said brake shoes into engagement with said brake drum, a crank for operating said shaft, and. means carried by said crank for operating said cam means so as to cause said brake shoes to at least partially disengage said brake drum.

2. In a power unit, a drive shaft, a support for said shaft, brake shoes pivotally carried by said support, a brake drum surrounding said shaft, a one-way clutch drivingly connecting said brake drum to said shaft, cam means slidably sup' ported on said shaft, complementary cam means for camming said brake shoes into engagement with said brake drum, a crank for operating said shaft, and means carried by said crank for operating said cam means so as to cause said brake shoes to partially disengage said brake drum, said clutch and said brake operating means being so constructed and arranged whereby said crank shaft is free to rotate in the one direction of rotation unhampered by said brake shoes but is prevented from freely rotating in the opposite direction.

3. In a hoist, a support, a movable element, means including a gear train for raising and lowering said movable element relative to said support, said gear train including a shaft, a rotatable handle mounted on said shaft for operating said gear train, said handle being so mounted on said shaft as to be tiltable in a direction other than the normal plane of rotation thereof, brake mechanism including a drum for holding said movable element in any given position, a clutch between said shaft and said brake drum, said clutch permitting relative movement of the shaft and the brake drum when the shaft is rotated to raise the movable element and causing the shaft and brake drum to rotate as a unit when the movable element is lowered, and means operated in response to tilting of said handle for rendering said brake mechanism ineffective.

4.-. In a hoist, a support, a movable element,

mechanism for raising and lowering said movable element relative to said support including a shaft, a rotatable handle pivotally mounted upon said shaft for operating said mechanism, means including a brake for holding said movable element in any given position, power transmitting means between said brake and the shaft, saidpower transmitting means including an overrunning clutch whereby operation of said mechanism in one direction disconnects said brake'means from said mechanism, and means operated in response to tilting of said handle about its pivotal mounting in a direction at right angles to the normal plane of rotation thereof for rendering said brake means ineffective during operation of said mechanism in the opposite direction.

5. In a hoist mechanism, a rotatable crankshaft for said hoist, a support for said crankshaft, brake shoes pivotally carried by said support, a brake drum surrounding said shaft, a oneway clutch drivingly connecting said brake drum to said shaft, cam means slidably supported on said shaft, complementary cam means for moving said brake shoes into engagement with said brake drum, a crank for rotating said shaft, said crank being pivotally mounted on said shaft for movement in a direction at right angles to the normal plane of rotation thereof, and means actuated by movement of said crank about its piv otal mounting on said shaft for operating said cam means, said complementary cam means and said brake shoes.

FRANCIS I. RATAICZAK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

Images