US1952728A - Hoisting apparatus - Google Patents

Description

March 27, 1934.

S. S. 'RATHBUN HO I ST ING APPARATUS Filed March 10, 1931' 2 Sheets-Shet l March 27, 1934. s, s. RATHBUN 1,952,728

HOISTING APPARATUS Filed March 10, 1931 2 Sheets-Sheet 2 [NKENTOR Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates, generally, to hoisting apparatus for handling light loads, but more specifically to telescopic hoists which raise loads by the application of power and lower loads by gravity.

Hoisting apparatus is often installed in hoistways of buildings for raising ashes from basements, as well as the raising and lowering of merchandise, supplies and equipment. In this application of hoisting apparatus, the greater part of the work consists of a raising operation only, such as raising cans of ashes, by'means of a hook and cable attached to a winding drum mounted above the hoistway opening, the hook being successively lowered to attach and raise the loaded cans. Since power is necessary only when actually raising loads, it is very desirable to provide means whereby the hook can be quickly lowered by gravity'to effect a considerable saving in both time and the cost of power.

It is also desirable to provide means whereby the raising and lowering operations can be controlled directly at the winding drum above the hoistway opening, usually at the sidewalk level. From this level, the operator can attach successive cans arranged on the hoistway floor, by swinging the hook attached to the cable. As each can is raised, a convenient mounting of the hoist-' ing drum frame permits swinging each can over on to the sidewalk until a number of filled cans have accumulated. The ashes are then emptied into a truck, or other vehicle, and the empty cans returned to the basement of the building.

The hoisting drum has heretofore been used to lower the empty cans, by reversing the driving motor. This results in considerable cost for power and in a loss of time due to the necessary slow lowering speed, since reversible motors usually run at the same speed in either direction. Gravity lowering by means of the hoisting drum often results in damage to the cans due to excessive lowering speeds. The above disadvantages of present hoisting equipment results in uneconomical and unsafe operation.

After the hoisting work has been completed, it is desirable to support the winding drum in a manner to permit of its being lowered into the hoistway. By so doing, the hoisting apparatus is removed from the sidewalk area and it can be protected from the weather by hinged doors which close over the hoistway opening in the sidewalk.

Hoisting apparatus of the class described is at present costly, ineflicient, and is hazardous to both the operator and the public, since the control of the present equipment is complicated and is lacking in a sufficient number of safety devices. Furthermore, the performance is unsatisfactory, uneconomical, and skilled operators are required.

Therefore, it is the object of my invention to provide improved hoisting apparatus which will be effective, safe, and economical.

It is a further object of my invention to provide hoisting apparatus which will utilize power for raising loads and lower loads by gravity, without the use of power.

It is a further object to provide hoisting apparatus which raises loads by power and lowers by gravity, with both of these operations controlled by a single lever.

It is a further object to provide hoisting apparatus wherein hoisting and lowering operations are controlled by common means incorporating inherent safety features, common means being utilized to perform both operations.

It is a still further object to providehoisting apparatus having means for raising and lowering loads as well as means for quickly and safely lowering light loads, independent of the raising means.

It is a still further object to provide hoisting 30 apparatus with safety controlled raising means and independent lowering means.

It is a still further object to provide hoisting apparatus embodying a safety controlled hoisting drum and means for elevating the hoisting drum 35 from an inoperative position to an operating position.

A still further object is to provide a hoisting apparatus by which loads may be raised by a cable attached to a manually or power operated drum, and by which loads may be lowered by gravity by either of a pair of cables attached to a drum, the relative movement of each of the pair of cables being opposite to provide continuous lowering of loads even while loads are being raised by the power operated drum.

The preferred form for my invention is shown, by way of example, in the accompanying drawings, in which:

Fig. l is a plan view of the hoisting mechanism partly in section.

Fig. 2 is a side elevation of Fig. 1.

Fig. 3 is a sectional elevation through the winding drum along line X-X of Fig. 1.

Fig. 4 is a sectional elevation of the independent gravity lowering device.

Fig. 5 is an elevation showing an installation of my hoisting apparatus.

Fig. 6 is a modification of the independent gravity lowering device shown in Fig. 4.

Fig. 7 is a section along line Y--Y of Fig. 5.

The hoisting apparatus herein disclosed comprises a telescopic standard consisting of a lower hollow, or tubular, post 11, having a base 12, as shown in Fig. 5, secured to the fioor of a hoistway 13, having hinged doors l4 and 15, which can be closed level with sidewalk 16. A tubular telescopic mast 17 concentric with lower post 11, is adapted to be telescoped vertically in and out of the lower post, by elevating handle 18, which turns a gear inside of gear housing 19 and in engagement with toothed rack 20. Mast 1'7 is guided and held concentric with the post by cap 21.

Telescopic mast 17 supports a U-shaped frame or bracket 22, by means of bearing 23 and hearing bracket 24, adapted to pivot frame 22, so that winding drum 25 can be swung around in a horizontal plane. A latch 26, is mounted on cap '27, secured to mast 17, and engages with notches 28 and 28', in frame 22, to steady the winding drum during the hoisting and lowering operations, and while the hoisting mechanism is being lowered into the hoistway. This locking means maintains, at times, fixed angular relationship between the frame and its support.

When latch 26 is depressed the load or can of ashes attached to hook 29 of hoisting cable 30 may be swung over onto the sidewalk. A spring 31 returns the latch into engagement with notch 28 as soon as frame 22 has been swung back to the hoisting position. A second notch 28 is provided to retain the frame over the sidewalk, at which time the winding drum may be used to haul loads to the hoistway for lowering.

After the hoisting cable winding drum has been raised to the operating position by means of elevating handle 18, the operator ascends to the sidewalk level to operate the winding drum. To raise a load attached to cable 30, operating lever 32 normally in a neutral position as shown, is raised only a slight amount, so that the clutch jaws of operating lever hub 33 will rotate switch lever 34 to depress the control button of electric control switch 35. This switch causes a magnetic motor-control switch 36 to start electric motor 37 attached to frame 22. The intermediate electric wiring is in accordance with usual practice and is not shown in the drawings.

The motor 37 is mounted in a manner which is an improvement on previous hoists of this type. Instead of mounting the motor 37 with its feet or lugs) on the bottom, in the usual manner, the feet are placed at one side in a vertical plane and the end plates of the motor turned 90 to keep them in the same position as formerly, so that the means of lubrication are not interfered with. Thismakes it possible to make a strong frame for the hoisting head with less we ght than formerly, since the vertical web to which the motor is bolted is the ideal form to attach to the mast 1'7, and to take the load with minimum weight of frame. This construction also makes possible the worm drive on the under side of the worm wheel, which is generally accepted as preferable to the drive on top of the worm wheel.

Electric motor 37 drives cable drum 25 by means of coupling 38, irreversible worm 39, worm gear 40, and normally engaged plate clutch 41, the worm and worm wheel being enclosed in an oiltight case 42. bolted to frame 22. Driving disk 43, of clutch 41, is driven by the hub of worm gear 40, by means of drive pins 44, adjustment for wear on the clutch plates being provided by adjustable clutch ring 45. Winding drum 25 is free to rotate on bearings 46, on through shaft 47,

is keyed to hub 48 of frame 22, to pre- :31) rotation, but is free to move axially as will be described.

As long as control lever 32 is held in the raising position, motor 37 will rotate the winding drum and raise the load attached to the cable hook. As the load reaches the upper limit of travel, weight 29, of hook 29, raises limit switch arm 49 and opens magnetic motor switch 36. Thus the motor circuit is opened and further rotation of the winding drum is instantly stopped by magnetic brake 50 on the armature of motor 37. This acts as an automatic safety device, should the operator fail to return the control lever to the neutral position when the load has been raised to its upper limit of travel. Thus magnetic switch 36 is a motor control switch and an upper limit switch combined as a common unit to perform both functions. By releasing the pressure on the control lever, the load may be instantly stopped and held at any point. Should the operator accidently release the control lever, a spring, not shown, automatically returns lever 32 to its neutral position and open switch 35. A stop 51 on switch arm 34, engages with a notch in hub 48 and limits the action of this spring.

The load may be lowered at any time by moving control lever 32 downward, or to the right in the side view shown in Fig. 2. Since stop 51 prevents the rotation of the switch lever in this direction, the inclined jaw teeth, or lugs, of control lever hub 33 will move over their mating teeth on the hub of switch lever 34, drawing shaft 47 to the left, Fig. 3, by means of nut 52. Collar 53, fixed to shaft 47, engages with clutch plate 54 and relieves the clutch plates of the pressure of clutch spring 55, thus releasing the clutch. Drum 25 is now free to rotate on shaft 47, thus rapidly lowering the load by gravity, the motor being inoperative and held by the magnetic brake. The load may be checked at any point of travel, by simply releasing the control lever, at which time coil spring 56 returns lever 32 to the neutral position, allowing the clutch spring to bear against pressure plate 54, moving shaft 47 to the right and l e-engaging clutch 41. The speed of lowering may be regulated as required, by manipulating the control lever only sufficiently to reduce the clutch spring pressure the desired amount. Clutch 41 serves the dual purpose of a raising clutch and a lowering brake. By proper design of the clutch spring 55 relative to the bearing surface of the clutch, it is possible to make the clutch yield at a predetermined load, providing against damage due to overload.

Shaft 47 is coaxial with the winding drum and with the dual raising and braking clutch, so that equal force is centrally exerted to control the clutch without the use of yokes, levers or other complicated mechanism. Since this shaft bears the entire load on the drum, a hollow shaft or tube may be provided with a smaller clutchcontrol shaft inside which will be free to move axially and engage with pressure plate 54 by means of a. pin extending through slots in the sides of the tubular shaft in place of collar 53; by this means the clutch is more easily engaged and disengaged.

Thus it should be apparent that power is required only while raising loads, lowering being accomplished entirely by gravity. Also, should the operator accidently release the control lever while lowering, the load will be instantly checked, the single control lever 32 serving the dual purpose of 2. raising and lowering control and acting as a safety or dead man control for both operations. The single lever control saves considerable time, especially while hoisting ashes, since the load can be raised, swung around, and lowered to the sidewalk, the winding drum swung back to the latched position, and the hook lowered for another can, without releasing hold of the control lever.

Instead of the structure. shown, the arm 49 may operate a small switch of the same type as switch 35, except that switch 35 is a normally open switch and for the limit feature a normally closed switch is used in series with switch 35, so that when arm 49 .is raised, this normally closed switch is opened and thus the magnetic switch 36 is opened. Instead of opening the magnetic switch in this manner, the arm 49 may do so mechanically, or this arm may be connected so that when raised it depresses the arm 34, thus opening switch 35, which in turn opens magnetic switch 36. Also, the switch 35 may be omitted and both the arms 32 and 49 operate switch 36 mechanically, in which case switch 36 is not of the magnetic type.

Empty ash cans may be gravity lowered by drum 25, but it has been found that, due to carelessness of operators, cans are lowered at excessive speeds, resulting in a shortened useful life of the cans due to damage when the cans hit the hoistway floor. Also by this method, considerable power and time is used in raising the hook to lower each empty can.

To overcome the above disadvantages I have provided means whereby empty ash cans, or other light loads, may be lowered quickly and without damage, as well as without cost for power. The winding drum frame is provided with an independent drum, or cable winding spoolf in the form of a grooved pulley 57, which revolves on a stationary shaft 59 provided with a key and a threaded end. An independent cable 58 having hooks 60 and 61, one at each end, passes over the V groove in pulley 57, so that when an ash can 62, attached to one of the hooks is lowered into the hoistway, the pulley will rotate. The lowering speed of the can is controlled by a hand-wheel 63 threaded on shaft 59. Pressure is thus obtained on the sides of, the pulley by means of keyed flange 64 and friction disk 65, causing the friction between the rotating and stationary parts to act as a speed regulating brake. As can 62, attached to hook 61, descends into the hoistway, hook 60 ascends to receive another can as soon as can 62 reaches the bottom. The V groove in sheave 57 grips the sides of the cable due to the pressure caused by the hook weights 66 and the weight of the cans. In this manner, the cable cannot slip on the pulley surface and loads, or cans, of varying weight may be safely lowered under complete control by regulating handwheel 63. If it is desired to lower heavier loads, a modified sheave, or drum 67 may be used, as shown in Fig. 6. Here the cable is passed around the drum several times to utilize the added adhesion or grip on the drum. A double drum may also be used, in which event two cables are attached and wound on the drums in opposite directions.

These cable-rotated drums may be made integral with winding drum 25 or mounted coaxial with the winding drum by suitable modifications in design. Both hoisting cable 30 and lowering cable 58 may be used simultaneously, greatly expediting the handling of ashes conveniently.

As already indicated, a substantial saving in power is eifected and the entire hoisting apparatus may be lowered into the hoistway where it is protected from the weather and at which time the hoistway doors may be closed and the entire area of the sidewalk made available. The hoisting apparatus is mainly constructed of stock materials and the many safety features provide safe operation even by an unskilled operator- While the structure herein disclosed is for electric power operation, other forms of power may be used for the cable winding drum and for the elevating mechanism. Other modifications of the structure herein shown may be made without de parting from the spirit of the invention herein set forth, or from the scope of the appended claims.

What I claim is:

1. In a hoisting apparatus, a frame, a winding drum mounted in said frame, an electric motor, a gear wheel actuated by said electric motor and in frictional engagement with said drum, a hoisting cable attached to said drum, a switch controlling said electric motor, a second switch controlling said first narned switch, switch controlling means attached to said cable, common means of controlling said second named switch and controlling the frictional engagement of said gear wheel and said drum, and means whereby said switch controlling means operates said first named switch to limit the upward movement of said cable.

2. In a hoisting apparatus, a frame, a winding drum mounted in said frame, a friction clutch member actuating said winding drum, a second friction clutch member, a motor mounted on said frame and adapted to rotate said second friction clutch member, an electric circuit for said motor, a manually operated lever, means for returning said lever to a neutral position after displacement. in either of two directions, means for disengaging said clutch members when said lever is displaced in one direction, means for engaging said clutch members when said lever is returned to said neutral position, means for closing said electric circuit when said lever is displaced in the other of the two directions, and means for opening said circuit when said lever is returned to said neutral position.

SHERRILL S. RATHBUN.

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