US2400299A

US2400299A - Lifting apparatus

Info

Publication number: US2400299A
Application number: US570631A
Authority: US
Inventors: George H Jones
Original assignee: National Tube Co
Current assignee: National Tube Co
Priority date: 1944-12-30
Filing date: 1944-12-30
Publication date: 1946-05-14
Anticipated expiration: 1963-05-14

Description

May 1; 1946 s. H. JONES LIF'IING APPARATUS.

File ad Dec. 30, 1944 N v T n W 5 w 8 0B 2 J articles during lifting thereof is prevented.

briefly stated includes a looped sling having terwhich has -wheels-4 at its opposite ends which trolley 8 in the pathof movement of the sheave Patented May 14, 1946 s PATENT OFFICE LIFTIN G APPARATUS George H. Jones, Lorain, Ohio, assignor to National Tube Company, a corporation of New Jersey Application December 30, 1944, Serial No. 570,631

' '7 Claims. ((1212-11) This invention relates to-in provements in liftins devices for articles such as iI Ot molds, the 7 main object of the invention being to provide an arrangement whereby tilting or tipping of such It is necessary in preparing ingot mold assemblies for reuse to lift the molds from the bases ,so that ;foreign matter can be removed therefrom. some im happens with onv n i a pp :rat s c m risi ir (linin sin he pp r ends attached to the erene hook and having bights on the lower ends which are placed over oppositely disposed lugs on the molds, that one of such bights will slip off its lug, which causes the mold toltip o r tilt since the crane operator cannot see that one of the bights i not properly positioned.

I haveovercomethe ioregoing hazardous condition by the arrangement of my invention which minal work-engaging bights which is freely mounted ntermediate itsends but includes means for preventing its withdrawal from-its mounting, and a limit switch which prevents the crane for operating the motor. l4 may also beconnected in series in the control circuit .24 and are suitably located in the cab [6. Elevation of the sheave above a predetermined height is thus prevented since the sheave 20 will contact-the plunger 29 and break the motor control circuit.

Instead of having slings suspended from the hook 30 on the sheave 20, there is provided a specially designed hook block attached to the hook 30 and carried thereby. This hook block comprises a .pair of side frame members 42 having a pair of superposed sheaves 44 and 46 rotatably mounted therebetween. The hook block 40 has a pair of links 48 at the upper end thereof 5 which are attached ,to an eye bolt 50 which is block being lifted sufliciently high to cause an unengagedbightof the sling from contacting the withdrawal preventing means when the other bight is in engagement with the article to be lifted. I

A preferred embodiment of this illustrated in the accompanying drawing, where- Figure 1 is an elevation;

invention is Figure 2 isan enlarged elevation of the hook 35 block; and V Figure 3 is a wiring diagram.

Referring more particularly to the drawing, the numeral 2 indicates a traveling bridge or'girder are adapted to travelcn suitably supported rails 6. Al crane trolleyfl is mounted for rolling travel intermediate the ends of vthe girder 2 on wheels in and is provided with a hoistingdrum l2, driven by an electric motor M, the ,operation ofwhich disposedon the hook .30. The eye bolt 50 is ad- J'ustably mounted between the links 48 as at 52. Accordingly, it is seen that ,the hook block 40 may be adjusted or rotated in a vertical plane relative to the. eye ,bolt .50. ,The side frames 42 areslightly twisted at approximately their midportions so that the sheaves.44 .and 46 rotate inverticalplanes butoccllpy vertical planeswhich are angularly disposed one with respect to the ther.

: ."flh specific form of loopedsling which I prefer is a continuousloop 6,0 freelysuspended intermediate its ends on the hook block 40, the lower ends iorming bightsfl land 64. ifhe lower strand ofv the sling passesoverand is carried by the lower sheave ,44 and the upper portion passes over and is carried by the sheave .46. The bight portions 62 and 64 may be .formed of chain links or the like to providesuflicient resistance to .the Wear or abrasion caused by engagementwith lugs on objects lifted thereby. The length of the sling j issuchthatifyone of the loops engages a lug on aniarticle a; be lifted and the other loop is 40 jfd seng'aged, th sheave 20will actuate the limit switch 22 before the disengaged loop is drawn around the uppersheave46. From this, it is seen that the sling is at least slightly more than twice as long as the upward movement of the sheave 20after an article to be lifted isengaged by both bights and before the limit switch is engaged by the sheave 20.

In use, it is seen that the angular disposition of the sheaves 44 and 46 opens up or enlarges the bights t2 and 64 of the sling 60 so that they may ,niore readily be engaged with the article to be lifted. Moreover, this angular'disposition causes the sling E0 to frictionally engage the sheaves and 46s; that if thesling becomes unbalanced the long end thereof will not draw the lighter end upwardso as to make positioning thereof over a lug difiicult. Since the length of the sling and the disposition of the limit switch are correlated to prevent an unengaged end or bight of the sling to be drawn around the upper sheave before the article to be lifted is tilted by reason of its engagement with the other loop, it is impossible for the article to be tilted in case of disengagement of one of the bights.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. Lifting apparatus comprising suspension. means, means for elevating said suspension means, stop means operable by said elevating means constructed and arranged to prevent elevating said suspension means above a predetermined point, a looped sling having terminal workengaging bights freely carried by said suspension means, means to prevent said bights from being withdrawn from said suspension means, said sling being sufficiently long to cause said stop means to operate before one of said bights engages the withdrawal preventing vmeans when lifted on opposite sides thereof, said sling being sufiiciently long to permitsaid stop means to operate before the bight on one end of the sling engages said upper sheave when only the other bight is attached to a, lug on an article to be lifted.

5. Lifting apparatus comprising suspension 'means, means for elevating said suspension means, stop means operable by said elevating only the other of said bights is attached to an article to be lifted.

2. Lifting apparatus comprising suspension means, means for elevating said suspension means, stop means operable by said elevating means constructed and arranged to prevent elevating said suspension means above a predetermined point, a looped sling having terminal workengaging bights freely carried by said suspension means, means to prevent said bights from being withdrawn from said suspension, means, said 1 sling being more than twice as long as the upward movement of said suspension means after an article to be lifted is engaged by both bights and before said stop means is operated whereby said stop means will be operated before one of said bights will engage said withdrawal preventing means when only theother of said bights engages an article to be lifted therebyj 3. Lifting apparatus comprising elevating means, a motor for elevating said elevating f means, a limit switchoperable by the elevating means constructed and arranged to stop said motor to prevent elevation of said elevating means above a predetermined point, suspension means carried by said elevating means, a looped slinghaving terminal work-engaging bights freely mounted on said suspension means, means to prevent said bights from being withdrawn from said supension means, said sling being more than twice as long as the upward movement of said suspension means after an article to be lifted is engaged by both of said bights and before said limit switch is operated by'said elevating means whereby said limit switch will be operated before one of said bights will engage said withdrawal means constructed and arranged to prevent elevation of said suspension means above a prede termined point, said suspension means oompris ing a pair of superposed sheaves, said sheaves being'rotatable in vertical planes, said planes being angularly disposed, a continuous looped sling freely suspended intermediate its ends on said sheaves, the upper strand thereof being suspended on the upper of said sheaves and the other strand being suspended on the lower of said sheaves, the lower ends of said sling forming terminal work-engaging bights adapted to engage the opposite sides of an article to be lifted, said sling being sufliciently long to permit said stop means to operate before one end of said bights engages said upper sheave when only the other bight is attached to an article to be'lifted.

6. Lifting apparatus comprising elevating means, a motor for elevating said elevating means, a limit switch operable by the elevating means constructed and arranged to stop said motor to prevent elevation of said elevating means above a predetermined point, suspension means carried by said elevating means, said suspension means comprising a pair of sheaves, a continuous looped sling freely suspended intermediate its ends on said sheaves, one strand of said sling being carried by one of said sheaves and the other strand of said sling being carried by the other of'said sheaves, the ends of said sling forming bights and being adapted to engage an article to I lifted.

7. Lifting apparatus comprising elevating means, a motor for elevating said elevating means,

'a limit switch operable by the elevating means constructed and arranged to stop said motor to prevent elevation of said elevating means above a predetermined point, suspension means carried by said elevating means, said suspension means comprising a pair of superposed sheaves, said sheaves being rotatable in vertical planes, said planes being angularly disposed, a continuous looped sling freely suspended intermediate its ends on said sheaves, the upper strand thereof being suspended on the upper of said sheaves and the other strand being suspended on the lower of said sheaves, the lower ends of said sling form ing terminal work-engaging bights adapted to engage the opposite sides of an article to be lifted, said sling being sufficiently long to permit said stop means to operate before one end of. said bights engages said upper sheave when only the other bight is attached to an article to be lifted.

GEORGE I-I. JONES.