US1673237A - Automatic crane grab - Google Patents

Description

Jue .12, 1928.

F. GERDES AUTOMATIG CRANE G n-A Filed Dec. 2, v1926 4'Sheetsf-Sh'e'et l Fig. z

F. GERDES AUTOMATIC CRANE GRAB June 12, 1928.y

Filed Deo. 2. 192e 4 sheets-sheet v 2 /nventbm .,Lw

`lune 12, 1928.

F. GERDEs AUTOMATIC CRANE GRAB Filed Dec. 2, 1926 4 Sheets-Sheet IIIIIIIIIIIIIIIII /n Vento/z' June 12, 1928. y 1,673,237

F. GERDEs AUTOMATIC CRANE GRAB Filed Dec. 2, 1926 4 Sheets-Sheet 4 /nventm Patented June 1 2, 192s.

y AUNITED' STATES PATENT OFFICE."

FRANZ GERDES, OF ESSEN-EUHR, GERMANY.

AUTOMATICCRANE GRAB.

Application filed December 2, 1926, vSerial No. 152,261, and in Germany January l9, 1926.

The invention relates to an automatic crane grab or gripping device for use either on loads which are enclosed in a container ora on single piece loads. Two constructional examples embodying a similar principle are illustrated by way of example in the drawings in which Fig. 1 is an elevation, partly in section, illustrating one embodiment of the invention.

2 is an lenlarged detail elevation of the movable ram and itsassociated parts.

Fig. 8 is a side elevation of the const-ruction shown in Fig. 2.

Fig. 4 is an enlarged elevation of a modification of the invention.

Fig. 5 -is a vertical sectional view taken at right .angles to Fig. 4. Y

' Figs. 6 and 7 are respectively a side elevation and a front elevation of the slide and arresting levers carried therewith.

Fig. 8 is a detail elevation showing the arresting levers carried bythe slide (Figs. G and 7) in their open position.

The grab in accordance with Figs. 1-3 lifts containers or any single piece loads which are capable of being gripped either'V underneath or by means of projections or otherwise. The grab or gripping device in accordance with Figs. 48 is of tong-like form.

lt is truc that semi-automatic tong-grabsl are known in which the opening and locking of the arms of the tongs take place ondepositing the tongs oii the load to be lifted. lVith such tong-grabs, however. some additional assistance is necessary for the purpose. of suspending and placing the load in them. In contra-distinction thereto the new gripping device in accordance with the present invention is entirely automatic and is characterized by its capabilityof standing, the central arrangement of the arm-lock and a separate locking device in its head. The new grab' or gripping device is there foresuitable not only for work at places where the load is easily accessible but valso as a so-called dipping grab for situations which are not in full view and are diiiicult of access by an attendant on account of heat, wet, steam, gas and the like. The extreme certainty with which the new grab meets the load is due to special precautionary means which almost entirely prevent the grab from swinging about its axis of suspension. l

Referring to Figs. 1-3, of the drawings, the gripping device or grab consists essentially of a frame-like body portion 1 in the middleof which is carried an upwardly and downwardly movable ram 2 having a plate 3. The ram has a longitudinai slot 4 extending through it and is provided at the side with a pawl 5 for actuating the mechanism. The bearings 6 carry a shaft 7 which kpasses through the longitudinal slot 4 in the rain 2, A star wheel Sand beside it a cam 9, for example of elliptical shape,` are fixed on the shaft 7. Canis of other shapes the two diameters of which are of different length may also be employed, their object being toenable diilerent distances apart'to be obtained for reversing purposes. -In order to avoid jamming a symmetrical elliptical cam 10 is also fitted on the opposite side of the ram 2. A bridge 11 guided by the ram 2 rests on the edges of the two elliptical cams and is connected by means of the. levers 12, 13 and 14 to the grab-claws 15 fittedy on the frame 1. At the head 44 of the frame or body portion 1 there is provided a suspension eye 16 which is laterally displaceable and in its position of rest lies approximately horizontal and of which the lower portions of the parts sur/ rounding the bolt holes are curved out somewhat elliptically so that, when the eye '16 is upright, they press against the shorter arms of the angle levers 18 but, when the. eye 16 is displaced. theyvallow the shorter arms of the levers 18 to fly upwards. These serve the purpose of automatically adiusting the closuie cheeks which clamp the block 42 of the tackle of the crane in order that the grab suspended from the hook 43 cannot k.at any time rotate relatively to the block 42.

The method of operation of this form of construction of the invention is as followsQ Atv the beginning ofthe operation the operator of the crane slips the hook 43 of the crane intothe suspension eye y16 and hoists, whereupon the two cheeks 18 close automat-ically and'press closely against the pulleyblock 42. -Rotation of the gripping device about the axis of suspension is thereby avoided and a so-called semi-rigidity is obtained without any guides. After the grab has encounteredthe load and on beingfur ther lowered the ram- 2 is pushed upwards v,

into the frame 1.V The pawl 5 rotates the star wheel 8 and with it the elliptical cams 9 and 1 0 about an angle of approximately 90. During this movement the bridge 11 slides over the periphery .of vthe elliptical cams until itis supported on their longerdiameter and has closed the grab-claws 15 vby means .of the levers 12,13 and 14, which takes place underthe influence ofthe weight ofthe grab itself. Vhile the load is being hoisted the ram I2 together with' the: plate 3 slides backwards into its. former position andthe pawl4 5 travelling therewith places itself ina position in which it is ready to engage the next ,toothot lthe star wheel 8. lhen the load is set down the grab is again lowered on to it. The ram 2 and the pawl 5 again rotate the elliptical cam about au auglle of 90 so that the bridge-11 is lowered on to ,the shorter diameter of the ellipse and thereby allows the claws to move outward. The centre inthe frame 1 about which the latter rotate ma bc varied as desired as may be necessitated y 'the' size of the load at the time, F urther, the elliptical curve may be 'connected by means'of transverse bolts 24,

and 29. The shaft 25 is journalledA in the side plates 23"and carries two cams 26 which are connected with star wheels 27. In the middle of the grab .is located the ram 28 which is guided by the 'transverse bolts 24 ries a and 29 and-.by the shaft 25, forwhich purpose the ram 28 is provided with longitudinal slots 30 and 31. It is therefore movable upwards and'downwards. The ram -28 carpawl 32 on either-side 'for driving the star w eels 27. The transverse bolt 24carries two arresting members 33 for the position of rest of the grab. Two arresting levers 34 which'are hinged to the^ slide 22 and are formed as lhooks at their lower ends rest against the cams 26. On the front of the grab (Fig. 5) there is fitted the adjustment disc' 36 the object of which is to secure the mechanism of the cams against undesired movement with the aid of the leaf springs 37. A construct-ion of the adjusting disc 36 as a kind of double indicator enables the position of rest or the gripping position of the grab to-be easily recognized. Rollers or-wheels 38 facilitate the forward movement of the grab along the groundor on rails. At the head 35-ot` the slideI 22 there is fitted a displaceable suspension eye 39 and hinges 40- together withl the closure cheeks 41.

, The method ot operation of this form of ameter is vertical.

.mechanism must be.A in its position of rest which corresponds to that `ac ljustment'of the elliptical cams 26 in-whicli` theirloliger di.-

In this position the hooks at thelower ends of the arresting lcvers 34 engage the carrying bolt of the arresting member 33 -for the purpose of lifting. `The operator of the crane allows' the hook 43 of the crane to slip into the suspension eye 39 and hoists. The checks 4l close against the block 42 and the hooks of the arresting levers 34 engage under the carrying bolt whereby the grab is held open. On lowering the grab on toI the load to be gripped the ram 28 is pushed upwards and 'its pawl 32rotates the star wheel 27 and the cams 26 through an angle of 90. During this the arresting levers 34 are spread apart by fthe cams- 26, the carrying bolts ofthe arresting members 33 are thereby freed and the position of rest is dissolved. The .op-

erator of the crane now hoists and the pair of jaws 19 closes and grips the load. During the lifting the ram 28 again slidesdownwards and the pawl 32' places itself iin posi-v tion to engage in front-.ofthe neixt'tooth of the star-wheel 27. Onsetting down the .load the grab is again completely set downen the load. The ram 28 and thev pawl 32 agam rotate the cams 26 about an angle of 90, andA the arresting levers 34 again support themselves against the shorter elliptical axes of the cams 26. Thefhooks of -the arresting levers 34 again slide. Under the carrying bolts of the arresting member' 33l so that .the grab again returns to the position of rest.

If, `after the operation is complete',-the grab is brought to its station, the closure cheeks 41 are opened yby a side thrust on the suspension eye 39 and release the hook 43 of4 the craneso that it is free to be removed. Y Iclaim:- i

1. An automatic grab "for cranes comprising a main body member, a pair of grab claws pivoted thereto, a ram shdably mounted on said body member, a pawl carried by said Tam, a bridge linked between said claws, and means interposed between sald bridge and body member and actuated by saidpawlfor controlling the operation ot' lsaid claws.

2. An automatic grab for cranesvcompris- -ing a-main body member, a pair of grab claws pivoted thereto, a ram slidably'mountled. on said'body member, a pawl pivoted' on said uram, a bridge and link connection between said claws, and a cooperating star wheel and cam mechanism interposed be- FRANZ GERDES.

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