US1886426A - Automatic grab - Google Patents

Description

H. REECHMANN AUTOMATIC GRAB Nov. 8, 1932.

Filed Feb. 25, 1931 2 Sheets-Sheet l I invemar: /7f efah mam;

LSAZQ NW. 1932. H. REICHMANN AUTOMATIC GRAB Filed Feb. 25, 1931 2 Sheets-Sheet 2 l'n e efifwz #8 (216% Man n Patented Nov. 8, 1932 UNITED STATES;

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nnrnnrcnnnrcnnann, on nnrsB ne-Rnrrnonr, GERMANY" AUTOMATIC "GR-AC3" ApplicationifilediEebruary25,- 1931, SeriaLNo. 518,176; and infGerm-any Eebruary28, 1930.

This; invention relates to an automatic grabin which-the-buckets are'linked on. a,

rigid. pulley box-to; pressure bars. Inall known .bucket grabs the grabbuckets which 5 are linkedon a p ulleybox to pressure bars are span of the jaws. The grab buckets of the known systems cannot therefore penetrate independently of one another more or lessdeeply ;into the materialto be dealt with according to the resistance of the latter.

In 'contradistinction thereto, according to the invention thegrabbuckets are provided insteadof with the internal pivot with bucket arms which arerigidly connected to them, ex.-

tend into the pulley box and are capable 0f moving; in thepulley box independently of one another,- By this means each of the buck.-

ets can swing independently about its onev pivot and. adapt-itself, independently of the other bucket, to resistance which it happens to strike. Whom entering; the v material to be grabbed.

Preferably the grab arms are guided in sliding paths provided on the pulley box, the main function of which is to enable the grab buckets to open uniformly, the positive opening of the grab being ensured bythe discharge ropes forming a pulley block arrangement between the end of the bucket arms and a point on the pulley box.

Such a grab is particularly suitable for unloading sea-going and river craft, as, owing to its small overall height, it can be introduced through the relatively narrow hatches into the holds, where, owing to the great span of the jaws, it automatically grabs even the material lying under the gangways of the ships and not within reach of the grabs hitherto used. The new grab has the further advantage that during the first half of the closing operation the buckets, owing to the toggle action of the pressure bars, dig themselves firmly into the material independently of one another, while in the second half of the closing operation .the material seized is shovelled: up, thegrab closing rapidly In the faccompanyingdrawings-a constructional exampleof the new grab ,isillustrated, ,Eigurel showsthe closed grab infront elevation, onlythe guiding means ofthe discharging ropes beingshown Figure 2 shows the pulleybox withthe;

the gmbisopen, I t

Figure; 3 -shows the grab whenopen, only the guiding means of; theclosing {IOPBS being; ho r Figur 4c .-sh ows the; pulley box with; the. guiding m an or: the loadi g or o ing ropes when the grab is closed.

Figure 5 is aside elevation offthe closed, grab partly-insection.

The, grab consists. of a rigid 1 pulley; box. a

on which theipressure bars 0, ojarepivoted about; points I), b. The other end' ofrthei pressure bars are pivotally attachedi t0 the; buckets L, L. Laterally of the bucketsand; connected rigidly with themare armstl, Z,"

which extendinto the pulley box, a in which;

they; are movable; independently, of one; an: other. For thispurposethe endsofthearms of; each bucket are connected-togetherby a transverse shaft 6,6: theiree ends of whioh areprovided withrollersfif which suitably ngagei groo srg, .9 provide n he: pulley box; The latter are bent ZEIOHlpPEtllS; of angle irons. 'Ilheends-of the bucketarms Z,,Z.'- can th'erefore move inthese cam'grooves; g1, g independently otone-another.

he ,cam grooves-g, gfor the shafts;;e, e5 are preferablyso shaped that theywexten'd in. the first; place fronithe; outside inwardly; in 3:3 horizontal direction. or at. a 5 slight inclinas tion, after; which they. rise in; the lifting? iirection. The shape of, the cam g-roovewvaries. according to the; purpose for which the grab ist'o be used andgthe material to be dealt; with, so ,asyto obtain a! suitable; line of engagement;

The' engagementiis further considerably; a s-;.

sisted bythe fact that the pivots 6,; bf ancL theipressure,barsc, c. in the-pulley boXl-a. re;- spread out-as fan-as possible, and Withasuit able construction of the: cam grooves 91,19, correspondi-gly. wide span of; the {opened-grab;

'gniding means forthe';disohargingrope when 7 is obtained and that the pressure bars act as toggles and make the buckets penetrate more readily into the material.

For opening and closing the grab two discharging ropes m, m and two closin ropes (loading ropes) n, n are employed. For the sake of clearness in Figures 1 and 2 only the rope guide for the discharging ropes and in Figures 3 and f only the rope guides for the closing ropes are shown. The two discharging ropes m, m are led ina symmetrical arrangement (Figures 1 and 2) in series over guiding pulleys 0, 0 over pulleys h, h and then round pulleys (Z, d and their ends aresecured at s and s in the pulley box a. The pulleys 0, 0 and 72,15 are mounted rigidly on the pulley box a while the pulleys (Z, cl are rotatably mounted on the movable axles e, 6. All the pulleys of the discharging ropes thus lie in one plane, as is shown in Figure 5, in which, for the sakeof simplicity, the pulley h is omitted. In the arrangement shown the discharge ropes m, m which are secured to the pulley box, together with the pairs of pulleys h, (Z and h, d form pulley block arrangements. When the ropes m, m are pulled these cause the axles e or e to be displaced outwardly and downwardly in the guides g, g from the upper position shown in Fig. 1 (Fig. 2), the movement being limited by stops 2?, 2." (only shown in Fig. l) on the pulleys f, f. In this position the buckets L, L take up the open position shown in Fig. 3.

The loading ropes n, 11/ coming from the crane cause the closing of the grab. These are guided in a symmetrical arrangement (Figs. 3 and 4) over guide pulleys p, 29 mounted rigidly on the pulley box a to the groups of pulleys D, D mounted on the movable axles e, 6. two innermost pulleys D, D each to a group of pulleys .7: or is rotatable about arfixed shaft K in thepulley box a. After two further turns round the pulleys D, is or D, is, the ends of the loading ropes are-crossed over and secured to the oppositely disposed axles e or e. In Fig. 5 the guide pulley 1) lies behind the innermost pulley k and the guide pulley p in front of the innermost rope pulley is. For the sake of simplicity the guide pulley p has been omitted in Fig. 5. The-loading ropes n, 11. together with the groups of pulleys is, D and 76, D form pulley block arrangements. When these ropesare pulled the grab buckets L, L are moved from the open position shown in Fig. 3 into the closed position (Fig. 1) the pulley axles e, 6 being displaced upwardly in the guides g, g by the pulley block arrangements In, D, k, D (Fig. 4). During the closing operation each bucket L, L can be adjusted independently of the other, the buckets being forced into the material by the pressure bars 0,0 acting inthe manner of toggles. The toggle action here is stronger, the further The ropes passover the the pulleys it, (Z or it, cl in the cam grooves g, g until the grab is open. 3 During this operation the cam grooves g, '9 cause the grab to open uniformly.

What I claim is:

1. An automatic grab with. a. large span having a pulley box, grab buckets, connectmg rods joining the grab buckets to the pulleybox, lateral pressure bars rigidly secured to the buckets, transverse axles connec'ting the free ends of the pressure bars, these free ends projecting into the pulley box, cam grooves arranged in-the pulley box, in which the ends of the pressure bars are guided, pulleys on the movable axles, pulleys in the pulley box, and ropes between the pulleys on the movable axle and the pulleys in the pulley box for opening and closing each bucket independently.

2. An automatic grab as claimed in claim 1 1 in which the rigid pressure bars of each bucket are independently guided in the cam grooves in the pulley box.

-3. An automate grab as claimed in-claim 1 having discharging ropes adapted to form a pulley block arrangement between the ends of the bucket arms and a point on the pulley box.

4:. An automatic grab as claimed in claim 1 in which the cam grooves are smooth and curved.

In testimony whereof I have signed my name to this specification.

HEINRICH REICHMANN.

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