US2801760A - Hoist - Google Patents

Description

Aug. 6, 1957 HOIST 2 Sheets-Sheet 1 Filed Jan. 9, 1953 55 @N on mw mm w a m m hm mm w w a m 2 g m m ,4 t @N w. 9

JAME'S CHRISTOFFERSON BYW W ATTORNEY Aug. 6, 1957 HOIST 2 Sheets-Sheet 2 Filed Jan. 9, 1953 INV ENTOR. Jclmes Chrlsrofferson BY 6; we

ATTORNEY m m m .h o 2 0 5 o 2 l w F 8 5 4 2 I rmvflfi H W w; 1 m n 2 r MW w s 4 7. M L 9;? imwiii I H 3 Q l 4 M 7 B Ill 2 2 E 3 m U w R w m m HOIST James Christotferson, West Newbury, Mass, assignor to Columbia Broadcasting System, Inc, Tianvers, Mass, a corporation of New York Application January 9, 1953, Serial No. 336,460

3 Claims. (Cl. 214-658) This invention relates in general to lifting devices and in particular to a semi-automatic aided lifting device.

The handling of heavy materials or assembly of heavy structures usually requires the use of power equipment. For most purposes, there are commercially available devices such as electric hoists or travelling cranes which are quite satisfactory. When however, it is desired to handle heavy members which must be fitted together or to move heavy units to or from confined areas, such devices often do not permit the necessary close control of power application or smoothness of motion.

In the manufacture of television picture tubes, present day production is concentrated on those having large screens. This means, of course, that the weight of each tube is considerable. An operator handling such tubes, in those instances where they must be removed from automatic conveying machinery, can not conveniently transfer the tubes from one place to another without the aid of power equipment. The usual electric hoists are on-olf devices not susceptible to close control of applied power and smooth motion which are required. A rough or jerky motion may result in a tube being dropped or bumped against nearby equipment or fixtures. Also, if tubes are being transferred from one position where the fit is close to another similar position, positive control without jockeying the tube up and down is desirable.

Therefore, it is an object of this invention to provide an easily controlled hoist having smooth motion.

It is a further object to provide a hoist which aids an operator in lifting materials, final control of lifting or lowering remaining with the operator.

It is a still further object to provide a device which is powered in a manner which retains the advantages of manual control of heavy objects being transferred without unreasonably limiting the weight of such objects.

It is another object to provide a hoist for safely transferring heavy objects of a fragile nature.

It is still another object to provide a hoist and vacuum chuck for use with television picture tubes.

In general, the present invention consists in a winch which is rotated through a fluid clutch. Provision is made for controlling the speed of the motor and, hence, the power applied to the winch, by means of a control device at the loading end of the winch cable. In the adaptation of this device to the lifting of picture tubes, further circuitry, vacuum lines, and suitable valves are provided for controlling the lifting force applied to such a tube. For a better understanding of the invention, together with other and further objects, features, and advantages, reference should be made to the following description which is to be read in connection with the accompanying drawings in which:

Fig. l is a perspective view, partly cut away, of a simple embodiment of the invention,

Fig. 2 is a perspective view of an embodiment of the present invention adapted to the handling of picture tubes; and

Fig. 2A is a schematic drawing of the electrical circuit 2,801,750 Patented Aug. 6, 1957 of Fig. 2 showing the details of a practical control circuit therefor.

Referring particularly to Fig. 1, there is shown a frame member 11 which is supported by an overhead trolley 12 movable in a first horizontal plane along a beam 13. Beam 13 is, in turn, suspended from a trolley 14 movable in a second horizontal plane normally perpendicular to the first plane as determined by orientation of a beam 15. A second trolley and beam arrangement disposed parallel to that at 14 and 15 is provided to insure adequate support for the entire apparatus. Mounted on frame 11 is an encasing shell 16 within which an electric motor is suspended. Adjacent motor 18 is atakeup reel 19 into which the power line for the device is fed. Attached to the rotating shaft of motor 18 is a fan and coupled to the shaft beyond fan 20 is a fluid clutch member 22. Flexible coupling member 17 connects the output shaft of fluid clutch 22 to a shaft 21 which is journalled in a pillow-block 24. Pillow-block 24 is supported from frame 11. There is also supported from frame 11, a second takeup reel 26. A winch 23 mounted on shaft 21 carries a length of cable 25. Cable 25 has afiixed thereto a control handle 26. Running from control handle 28 to second takeup reel 26 is a power line 27. A hook 230 is provided at the end of cable 25 to accommodate. a load of any type.

In operation, hook 3ft is attached to a load :to be lifted or transported from one place to another. The operator of the device, by manipulating the pistol grip provided at control 28, varies the amount of powersupplied to motor 18. In the simplest case, motor 18 may be a D. C. motor and control 28, a rheostat. This need not be the case, however, as a variable transformer of small size might be substituted for the rheostat in 28 in an A. C. motor substituted for D. C. motor 18. Other controls, electric, pneumatic, or otherwise might also be used with suitable driving means. As the operator advances the rheostat, more power is applied to motor 18 causing greater torque to be applied to winch 23 through fluid coupling 22. power may be applied to the motor to overcome the weight on hook 30. The operator, by manipulating the pistol type control, may exert as little or as much effort, personally, in the lifting operation as he desires. In some instances where it is necessary to fit heavy objects into constricted areas, it may be desirable to increase the amount of manual lifting in order that the operator does not lose precision derived from personal handling of the load. At those times, by releasing the trigger of the pistol grip to the necessary degree, the operator may determine the exact amount of manual effort to be exerted.

Because of the nature of the device, where a load is normally handled at some distance from. the Winch, the flexibility of the cable will permit loads to be moved about a considerable area beneath the device. However, to further increase the effective area over which the device will operate, tracks 13 and 15 with trolleys 12 and 14 are provided. Motion on these tracks may be controlled either by handas shown or by power. The amount of power necessary to lift the cable, the control, and hook may also be applied by relatively little compression of the trigger of control 28. Takeup reel 26 maintains power line 27 reasonably taut during manipulations of the load. Similarly, when motion is had along either of the tracks, takeup reel 19 maintains tautness in the input power line.

Referring now to Fig. 2, the invention is shown in its adaptation for the lifting and transporting of picture tubes. A picture tube 31 is suspended from a vacuum chuck consisting of a resilient ring 32 which may be of rubber and is attached to a plate 33. An opening is formed in plate If the object is quite heavy, considerable 33 and a tube 34 communicates therewith. A pistol grip 35 is mounted on plate 33 and carries a rheostat 36 and a double throw locking switch 37 which may be push button controlled. Tube 34 has clamped thereto a flexible line 38 which runs to a T 39. One side of T 39 is connected by a flexible line to a vacuum pump 51) as indicated. The other side of T 39 is open to atmospheric pressure. A cable 40, a switch line 41 and a rheostat line 42 run to an overhead system which may be similar to that shown in Fig. l, in that a winch is provided for cable 40 and takeup reels for lines 41 and 42. A second T 43 is provided in the tube running from flexible line 38 to T 39. In the stem of T 43 is a bellows vacuum switch 44 to which is connected one side of switch line 42 and one side of a motor line 45 running to a motor which may be similar to that shown in Fig. l. A normally closed solenoid valve 47 is inserted in the side of the pipe line running from T 39 to the end opening on atmospheric pressure. Another solenoid valve 48 is inserted in the flexible line from T 39 to the vacuum pump. One side of a power line 49 connects to one terminal of solenoid valve 47 to one terminal of solenoid valve 48. The other terminals of solenoid valves 47 and 48 are connected back through switch line 41 to the double throw switch 37 carried on pistol grip 35. The other side of power line 49 also connects to double throw switch 37. These electrical connections are clearly shown in Fig. 2A.

The apparatus operates in a manner described in detail below. Power is applied to line 49 and the vacuum pump 50 is started. Solenoid valve 47 then opens and solenoid valve 48 closes, power reaching them through normally closed switch.37. The motor operating the winch is preset to provide just enough torque at the winch to overcome the weight of the pistol grip, vacuum chuck, and depending lines. When the operator desires to lift a picture tube, he places the chuck against the face of a tube and presses a button of double throw switch 37 opening the circuit through that switch and de-energizing solenoid valve 47 and solenoid valve 48. This causes solenoid valve 47 to close and solenoid valve 48 to open, air being drawn from the area under vacuum chuck 35 through tube 34 and flexible line 38 which may be looped or otherwise supported by conventional means to retract or move it with pistol grip 35. When suflicient vacuum has been achieved, bellows vacuum switch 44 is actuated, placing rheostat 36 in circuit between a power source and the motor. The operator is then able to apply lifting power to the tube by compressing the pistol grip and thereby adjusting rheostat 36. The tube is then lifted and placed in the position desired, at which point it is released by the operator pressing a button of switch 37 to close the circuit of solenoids 47 and 48. Solenoid valve 47 then opens and solenoid valve 48 closes. Outside pressure enters the vacuum chuck by way of valve 47 and line 38 permitting the chuck 35 to be released from vacuum tube 31.

Other modifications and improvements of the device .will be apparent to those skilled in the art. For example, a braking device may be added to the winch to prevent loss or damage in the event of power failure. The operation of the solenoid valves is such that the vacuum chuck will, when loaded, maintain its load for a considerable period after power failure. The device may be made as mobile as desired and need not be used in conjunction with the precise type of overhead travel shown. The use of power for any desired motion, or of other types of control of the motor may be easily arranged. The invention should only be limited by the spirit and scope of the appended claims.

What is claimed is:

1. A hoist comprising, a winch, an electric motor, a

fluid coupling between said winch and said motor, a source of voltage, a cable coiled on said winch and having a free end, a vacuum chuck attached to said free end, a manually operable voltage control device disposed on said vacuum chuck, a bellows vacuum switch, a power line running from said source of voltage through said voltage control device and said bellows vacuum switch to said motor, a portion of said power line running parallel to said cable from said Winch to said free end, a vacuum pump, a vacuum line running from said vacuum pump to said vacuum chuck, and means disposed on said vacuum chuck for opening and closing said vacuum line running thereto and operating said bellows vacuum switch in a predetermined time sequence with opening and closing of said vacuum line.

2. A hoist comprising, a winch, an electric motor, a fluid coupling between said winch and said motor, a source of voltage, a cable coiled on said winch and having a free end, a vacuum chuck attached to said free end, a manually operable voltage control device mounted on said vacuum chuck, a power line running from said source of voltage through said voltage control device to said motor, a portion of said power line running parallel to said cable from said winch to said free end, a vacuum line running to said vacuum chuck, first and second solenoid valves in said vacuum line, and a switch mounted on said vacuum chuck for controlling said first and second solenoid valves to connect said vacuum chuck to said vacuum line or to external air pressure.

3. A semi-automatic travelling hoist comprising, a first overhead railway disposed in a first direction, a second overhead railway disposed in a second direction perpendicular to said first direction, said second overhead railway being free to move along said first overhead railway, a lifting unit movably mounted on said second overhead railway, said lifting unit including an electric motor, a winch, a fluid coupling between said electric motor and said winch, a cable coiled on said winch and having a free end, a vacuum chuck attached to said free end, a source of voltage, a voltage control device mounted on said vacuum chuck, a power line running from said source of voltage through said voltage control device to said motor, said power line being disposed parallel to said cable from said winch to said free end, a take-up reel for maintaining said power line physically parallel with said cable from said winch to said free end, a vacuum line connected to said vacuum chuck, solenoid valves in said vacuum line for connecting said vacuum chuck to said line or to external air pressure, and a switch mounted .on said vacuum chuck for controlling said solenoid valves.

References Cited in the file of this patent UNITED STATES PATENTS Re. 22,785 Clay Sept. 3, 1946 2,061,044 Ringe Nov. 17, 1936 2,320,758 Sinclair June 1, 1943 2,321,525 Schroeder June 8, 1943 2,390,242 Engler Dec. 4, 1945 2,391,580 Mackmann et al Dec. 25, 1945 2,576,872 Young Nov. 27, 1951 2,581,742 Young Jan. 8, 1952 2,600,887 Lannen June 17, 1952 2,620,161 Royer Dec. 2, 1952 2,666,876 Sinclair Jan. 19, 1954 OTHER REFERENCES Fluid Drive for Mining Machinery by John D. Rosebrough, Mining Congress Journal, 1941, pp. 30-34.

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