US2266660A - Cable safeguard - Google Patents

Description

Dec. 16, 1941. s. N. sLoAN f l 2,266,660-

CABLE SAFEGUARD Filed MaIOh 7, 1940 a I 'E ihustmn N. 5mm

Patented Dec. 16, 1941 azteca@ CABLE SAFEGUARD Sebastian N. Sloan, Toledo, Ohio, assigner to The Maylc Manufacturing Company, Toledo, Ohio,

a corporation of Ohio Application March 7, 194.0, Serial No. 322,769

Claims.

The invention relates to the maintenance of a vertical direction of cable travel in a plane from a point or axis.

This invention has utility when incorporated in draft or line cables for telpherage or in hoisting and power shifting and lifting of work, more particularly with the bridge type of crane having a power operated cable drum thereon, wherein such powermay be cutout automatically when the direction of the cable approach slants to the drum axis beyond a minimum from the perpendicular to such axis.

Referring to the dra-wing:

Fig. 1 is a view, with parts broken away, showing an embodiment of the invention in a bridge type of crane;

Fig. 2 is a section on the line II-II, Fig. l, showing the control box for the tiltably operable cut-out switch herein;

Fig. 3 is a View on the line III-III, Fig. 2, of this box-.housed switch- Fig.. 4 is a View generally on the line IKL-IV, Fig. 2, showing the mercury switch devices in the control box;-

Fig. 5 is a section on the line V-V, Fig. 4, showing the mounting of the clip for a switch terminal; and

Fig. l6 is a wiring diagram of the control.

Along tracks Iv bridge 2 may be shifted as bypower means from a remote operator. This bridge 2 mounts carriage 3 of a hoist having drum 4. Fixed with this carriage 3 is one end of cable 5 passing about block or connector 5 having load-engaging hook 1, and then back into grooved ways 8 in the drum d. A cut-out switch housing IIJ is suspended from carriage 3 by chains 9 and is xed to cable 5 at a point spaced from the carriage 3. There is thus provided a control against excessive rise of the block E, for as such block strikes this box I or too closely approaches thereto, cut-out switch II defeats driving operation of motor I2. As herein disclosed, there is push control switch I3 having iiexible drop I4 from the carriage 3. Power supply to the carriage 3 may be from trolley I5.

In practice with the larger units, the switch i3 may be a reversing switch and the cut-out switch IIJ in series therewith to eiiect cutting out of the power current to the motor I2. In smaller units where less power is used, these may be regularly in the supply or power circuit.

In the handling of loads the hook 'I may be moved in a plane perpendicular to the axis of the drum below bridge 2 as this 'does not cause damage to the equipment as the line of direction Y comprises a cut-out.

of cabl-e 5 will approximately be in a plane perpendicular to the axis of the drum fi or radial to drum 4. However, in practice, when the carriage 3 is shifted along the bridge 2, the workengaging hook 'I may have a slant toward the drum 4. This means an out-of-normal line direction of draft for the cable 5 as to the grooves 8 in the tdrum 4. Such means an axial direction of extent for the cable 5 in its approach to or away from the dr-um 4. There is thus a tendency to crowd out of the groove or cross a wound portion of the cable. This, in the strand type of cable whether of wire or hemp type, has a tendency to fray or wear the cable unduly. There is thus a shortening of the cable life and the introduction of a hazard as to cable strength, which hazard may not only be that of equipment but as to the workmen. It is true the operator may readily shift the carriage 3 to bring the position of the block E to approach a plane perpendicular to the axis of the drum 4 for the line of direction of the cable 5. However, in normal functioning of work, yunforeseen conditions or miscalculation by the operator may bring the block B into this disturbing relation as Vto the carrier and drum. An automatic safe-guard is herein provided.

This safeguard against draft line slant toward a plane perpendicular to the axis of the drum In this cut-out bolts I6 may draw plates I'I against cut-out box or housing I8 for notch I8 to grip the cable 5. The location is desirably at a position on the cable 5 or near the block 6. Bolt I8 mounts closure plate I8 on the housing I 8. The lswitch II may maintain its normal functioning against attempt at too high a lift or lift too close to the carriage or carrier 3 for the block 6.

This block or housing I8 has therein insulation lining 20 with corner lugs 2l engaged by screws 22 in positioning insulation block 23 spaced from the under side of this box I8. This insulation block 23 has terminal screws 2li for lead-in connections 25. The screws 24 as engaging block 23 pass through slots 26 in conductor strips 21 which may be connected by rivets 28 in double pronged spring clips 29. These clips 29 are swiveled thereto. Between this pair of clips 29 there is xed by screws 3i] strap unit 3l carryinggclips 32. A pair of the clips 29, 32, may be aligned to receive therein a fixture having medial insulation body 33 and terminal contact portions 34, 35, spaced by this insulation portion 33. This unit 33, 34, 35, has chamber 36 therein for mercury 31, say along the type of Davis Patent No. 1,905,813, April 25, 1933.

The location of the fixed connector strap 3l is medial and the clips 32 are swiveled thereto, thus fixing as to the screws 30 an angle or position for this strap 3| as to the insulation block 23. However, the slots 2S in the strips 21 permit adjustment for the desired angle of sensitiveness for these automatic mercury switches to act. This action by the switches for cutting out or opening the circuit between the leads 25 is one which is not eiected as the hook or block 6 may swing or be drawn in a plane approximating perpendicular to the axis of the drum 4. However, as such pull or swing position for the block as to the drum 4 in the lines of direction of the cable 5 thereto may be longitudinally of the axis for such drum 4, the disastrous condition of the cable lead may arise when the cable is led into or out from the drum. With such undesired condition determined, this switch may have its control adjusted to at once become effective on such tilt, herein shown by dotted lines in Fig. 1, as in the direction of the one strip 21 approaching the axis of the drum 4 and the other strip 21 receding therefrom. The mercury 31 is thus shifted in one or both of the chambers 36 to break the circuit between the leads 25. The motor I2 is thus cut out and the operator is now compelled to re-locate the block 6 or the carrier 3, which brings the line of pull more nearly to approximate the perpendicular plane to thereby safeguard the cable 5 from hazard.

What is claimed and it is desired to secure by United States Letters Patent is:

1. A direction limiting means for a suspended hoist cable comprising a winding drum, a cable suspended at one end from said winding drum and having its other end fixed, a load engaging means suspended by said cable, drive means for rotating said drum, a controlcircuit for said drive means, and an electrical device connected to the cable between the iixed end and said load engaging means and in said circuit to stop operation of said drive means on movement of said load engaging means along the axis of said drum but permitting movement of said load engaging means transverse to the axis of said drum.

2. In a bridge crane, a direction limiting means for a suspended hoist cable comprising a Winding drum for the crane, a cable suspended at one end from said Winding drum and having its other end fixed with the crane adjacent the drum, a

load engaging means suspended by said cable, drive means for rotating said drum, a control circuit for said drive means, and an electrical device connected to the cable between the xed end and said load engaging means and in said circuit to stop operation of said drive means on movement of said load engaging means along the axis of said drum but permitting movement of said load engaging means transverse to the axis of said drum.

3. A direction limiting means for a suspended hoist cable comprising a Winding drum, a cable suspended at one end from said winding drum and having its other end xed, a load engaging means suspended by said cable, drive means for rotating said drum, a control circuit for said drive means, and an electrical device connected to the cable between the fixed end and said load engaging means and in said circuit, said device being shiftable relatively to the drum to stop operation of said drive means on movement of said load engaging means along the axis of said drum but permitting movement of said load engaging means transverse to the axis of said drum.

4. A direction limiting means for a suspended hoist cable comprising a winding drum, a cable suspended at one end from said winding drum and having its other end fixed, a load engaging means suspended by said cable, drive means for rotating said drum, a control circuit for said drive means, and an electrical device connected to the cable between the fixed end and said load engaging means and in said circuit, said device including a switch tiltable relatively to the drum to stop operation of said drive means on movement of said load engaging means along the axis of said drum but permitting movement of said load engaging means transverse to the axis of said drum.

5. A direction limiting means for a suspended hoist cable comprising a winding drum, a cable suspended at one end from said winding drum and having its other end xed, a load engaging means suspended by said cable, drive means for rotating said drum, a control circuit for said drive means, and a mercury switch connected to the cable between the fixed end and said load engaging means and in said circuit to stop operation of said drive means on movement of said load engaging means along the axis of said drum but permitting movement of said load engaging means transverse to the axis of said drum.

SEBASTIAN N. SLOAN.

Images