US2656212A - Automatic tong extracting and resetting mechanism - Google Patents

Description

Oct. 20, 1953 I E. E. ECKSTEIN AUTOMATIC TONG EXTRACTING AND RESETTING MECHANISM Filed Aug. 5, 1952 4 Sheets-Sheet l IN V EN TOR. ERNESTE ECKSTE/N b k 24M ATTORNEYS AUTOMATIC .TONG EXTRACTING AND RESETTING MECHANISM.

altomeg 20, 1.953 E. E. scKsfi-zm 2,656,212

AUTOMATIC "IONG EXTRACTING AND RESETTING MECHANISM 4 Sheets-Sheet 3 Filed Aug. 5, 1952 Patented Oct. 20, 1953 OFFICE AUTOMATIC TONG EXTRACTING AND RESETTING MECHANISM Ernest E. Eckstein, Elgin, Oreg.

Application August 5, 1952, Serial No. 302,707

Claims. 1

This invention relates to a tong operating mechanism for use in connection with log handling equipment; the present application being a continuation in part of. my co-pending application filed under Serial No. 280,886. More particularly, the invention has reference to an auto-- 7 matic ton control apparatus designed primarily for use in connection with the cable and cable winding mechanism of any of the present day hoisting machines, 01' loaders, as employed for the handling and more particularly for the cold decking of logs. It is not the intent, however, that the present invention shall be limited in its use to log handling operations but that itbe understood to be applicable for any other use not inconsistent with its structure and disclosed mode of operation.

It is the principal object of this invention to provide a simple, effective, and automaticallyoperating tong extracting and tong re-setting means for use in connection with a cable and. cable winding devices as employed for the lifting and loading of heavy objects by means of a pair of tongs; the present apparatus being operable to effect the extraction of the teeth of the tong jaws from the lifted object after it has been lowered and brought to rest on asupport, and

for then resettingthetongs for self closing on the next object that is to be lifted thereby.

More specifically stated, it isthe primary object of this invention to provide a mechanism for cable, after the lifted log has been lowered to a position of rest onasupport. 4

It is a further object of this invention to. provide a tong extracting and re-setting mechanism of the above stated'character, that eliminates other objects of the invention, I have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a perspective view of the automatic tong control mechanism embodied by the present invention as functionally associated with a hoisting cable and pair of log lifting tongs.

Fig. 1a is a similar view of the device as seen from the sides opposite those shown in Fig. 1a.

Fig. lb is a view showing manner of applying open tongs to a large log.

Fig. 2 is an elevation of the present device, as seen from the latch mounting side.

Fig. 3 is a horizontal section taken on line 3-3 in Fig. 2.

' Fig. 4 is a sectional detail, taken on line ll-4 in Fig. 2, showing the slack pulling mechanism for the hoisting cable as mounted on one 1 respectively, sequential operations for the extraction and then the re-setting of, the tongs.

Fig. 12 is a perspective view of certain parts of the latch releasing mechanism.

the usual requirement of an extra workman for 7 that purpose. Furthermore, an automatic tong extracting and re-setting mechanism that is powered by and controlled entirely throughma- ,nipulation of the hoisting cable, under control of the hoist operator. a Further objects and advantages of the present invention reside in the details of construction .and

combination of parts employed therein, in their to form a rigid, tubular housing. However, a

Referring more in detail to the drawings The mechanism of. this invention, as used in combination with a pair of tongs and a hoisting cable, comprises a rather elongated, hollow or tubular housing I0. This housing, preferably is uniformly square in horizontal cross-section and is open from end to end, as shown in Fig. 9. In the present; instance, the housing It], as best shown in Fig. 8, is made'of two pieces of angle iron, lila and [01), having equal lengths and equal cross-sectional dimensions; these irons having their flanges disposed edge toedge, and welded together along the engaged edges, as at Ii, thus similar housing, together with the flanges shown thereon and later described, might be cast in a single piece, or otherwise formed, without ideparting from the spiritof the invention. 111 a devi n w in. ie 19 v hand large logs, t

housing In is thirty inches long and measures about four inches across each side face. It provides an inside passage that is three inches square in its horizontal dimensions.

For purposes presently understood, the housing in is formed on each of its four sides and extending,,.the iullleng th thereof withvepaced parallel flanges Eor liu r pose bfgegcplanationwthe four sides" of the housing have been designated in Fig. 8 by reference letters A, B, C and D, and

the parallel flanges as formed on these four sides respectively have been designatediibyireference letters aa, 12-1), -0 and dd. 'ililheseflang'es serve as mounting means for various parts or mechanisms located between thenraild 'al'sd'they protect these mechanisms daimfl eginlthe rough use to which the device is subjected.

Slidably contained in the tubularhou'singlfl, are the overlapped inner end portions of two elorig'ated- -rnetal bars designated -respectively by fiumerals ng and--13. lnthe pr'esent device these biirs are ach Etkrirty-six :inches longs-one =-inch *t'hick ahd'threeinches wide'; and each: has. a part thereof freely movable endwise in thehousinabeiivi en definite -limits. '1 The-bard z extends trom e upper end of the housingimand theabarcl3, 'likwiseg extends from the lower endthere'of. lion adjacent sid faces ofi theiri'ove'rlapped end .portions} the b'ars 2' and- 1 3, are equipped .resp ectively "witlr integrakblocks-or i1ugs -t2a i and. 13m, tliat are adapted: to :eng-age one againstthe-other, endtoend, as shown in Figs. =:9\.and1 .11; -:thus:to torm a row- 11mm connection-between thetwo bars. However} thetwo-bars, under-mertain-com' -'"ditions' as presently explained bari move endwise relative to each other and to housing 10, as indicatectby their' 'showing in -EigsiQ, and 11.

Atits upper end; th-bar =1Z has-.a U shaped ioob-forrhir'rgmemberfl 5, .welded onotherwiseattached thereto and to this loop' theouter endl'of a hoisting-cable 1 6 --is attached; it-lbein'g understood that -this" cable is extended to the loop from :the cable winding drum of a hoisting machine, -0r wiriehwfi any suitable kind-"that may be designed 'o'r llused for 'the lifting andl loading of logs. For example, the hoistingmachine;not heremishown,

- may be/ia boom {type vloader ofthe character of th t showrr-in'sUfi s Batent No; g2;327.0l'5;;issuecl =-i ts -'lowerend; thet bar l3ehasa-- U-shaped loop 18 welded thereto. Applied through the loop i i-8'are cle'visest9 and i9 and these pivotally conrlect the loop l-8 with' theupperiendsofa pair of tongs -t1 1es'etongsbeing of the kind 'normal1y 'used fotlog handling purposesand its jaws are equipped with inturnedpointed-teeth 20'. as herein shown. Z'Theitongs are permitted, byareason =of i-thisi-mean'siand manner :ofatta'chmentto the lcl'oop rl8stoa=be .opened and; closed; yet .willretain atheirl' atransverse-lrelationship to iithe housing I J 0 as-Jseennin Eiglil. IUnder weight .iof-..a'zlog,lthe ajaws'bf the tongswilltend to closetogethert thus to.i'naintain.Lth'eir hold-011 3. Jog tocwlriclilth'ey wareapplied. llsua-llyxthemeeth.embed themselves .in tlie log. to substantial. extent.

'iltiw-ill be understood further that, when the bars: ll andfl are in suchposition that their inner end lugs-12w and Ba; are 'abuttedor hooked together; for example as:seen in Fig. 9', they serve i as ja connecting linkage betweem cable '16 and *gtongsi 0 through which the load sustained by the 'c'able can belifted a load, in the arm: of 1 a-log *IBQiS ShoWnin- In the usual 1 handling operationwhere the hQistihgcabIe is "attached" directly to the tongs,

it is a diffioult and a dangerous task to manually extract the points of the tongs from the log. The present mechanism has been designed to make extraction easy and to eliminate the extra work- 5 man heretofore required for this job. The release mechanism is controlled entirely through 4 the hoistingpable, and requires no extra manual 3; help either iomthe extraction of the itongs or for their resetting. Extracting of the tongs is 1 0 effected through use of a length of chain 30, or

"'fiexible cable, that is attached at one end to an ssjey'eletttliomnneiziaw of the tongs and is attached aat'it'swbther end to the housing I0.

In the present showing of Figs. 1 and 2, the

'15 'upper' en'dof the chain is attached to a cross itlrlatzextends between and is fixed in the f l a nges, d-d on one side of the housing [0. A "pluraiity of vertically spaced holes 33 are formed along the flanges to .iprovide for mounting the zoscross member 32 at the most practicaklocation to :provide a limited: amount. of slack in, :the;ichain, -when thespartst are .set as zin Fig. 1.

i T-he releaseeof the i tongs from; aa-iogathrough :the mediacyof the .hoisting cable. l6 is .madetposg5 sibleinJ-i-theapresent: instance by. the .provision (of: aneans.-.forzi;temporarily establishing through -the chaimall 'ithelogliftingconnection normally -eXisting .throughlbars ti Landau ,and temporarily uproviding. a 1imited:.slack, or. .lostzmotion c'in :the

0 :connection with the; tongs .as. ,providednthrongh the.bars l 2 and il 3. transfenofvconnection .tos.x:haini;3.0 :is made possible: by; use; of'ra zlatch mechanism'. to: establish. a'. direct :connection heutween barLlZ and housing 10.afterztherlostmotion 35 has been-providedzintherconnectionithrough'bars l2 and I3. This mechanism, now deSQlibBdQWith .references to. 1theishowing ofpartsinrfigal l0 and -.1 1 .-iS.-.aS'1-fO11QWS :Wielded .or. .othenwiserifixedzto the; upper; end 4o -.por tion;ot the'zbartll :through; the; me'diacy :of. a

spacer block38-, i iazflat banal!) .whichsis substantially .zcoextensive avith bar I 2.v and .which extends '.=:therealong';ibut passing: outsideof, the;ho.using :l 0 -:between cthe:i.-fianges c711 thereof as noted" 5:iEigs.1'.8,z '9 4:10;; and 11. '.;Weldedr ;to'; and; directly .-.a-cross; the.;outen face of bar:.-;4 0, .near; its xnedial :pointais ai lug; or stop-1:4 I Located: betweerrathe fianges,.- (Ir-11,; and. piyotally: mounted 011;. a horibZZOIXtaIZiCI'QSS.11111442, extended,;therethrough,iis a .:downwardlyi andninwardly; directed latch; A l; of zzbar form; thelower end of .whichis. adapted, upon {lithe 1132,1321! 2.;beingr:f11lly.-.telescopedeintoxthe 'housand.-:thevloan .40- being1movedidownwardlysac- .icordinglygztdzbe-engaged againstgthe;=top.;pf:)the

; nstop L41) thus to;..proyide .a':liftingzsconnectiqnybei tween gthe: bar. l2iandghousing ll 0.

:ThezlatchaMisateall timeszyieldinglysurged t 1 warddatched. or holdingrpositionzbyian irmerted .3Uashapedspringiz5i0,-.disposed under compression 6Q: betmeen-thezlatchcendi a .cross-platei i,.;that; ex-

tends between and isiwelded:tozthexfiangesl are; otheospringibeingheldrinuplace.by a,-.bolta52 l-that irisrfixed in the latehiand extendsoutwardly thereizfrom and'4throughlopenings, in the :legsiof .the 5 5U sshap'edx spring and. .freelyithroughi-zan openaing -51 tsin'lthe plate=5l -,-.as .seen in Fig.:39.

As a means for efiecting the. unseatingotethe latc'hlM' i-romholding:contacttwith the stop'sqlato .-release::this connection: I have. mounteda latch release lever 60 on a pivot pin-6| that isextended horizontallybetween paired, outwardly-project- ;:ing--ears* 62- 62 applied to the lower iendiofthe la'tch.

'-I he' flower end; portion of the =lever 60--has a longitudinal1-y'-curved= cam surface fifl =extended upwardly along the latch and is adapted to be engaged and outwardly actuated by a release mechanism which will presently be described in connection with the showing in Figs. and 11. Also, for a purpose presently apparent, a wedge shaped block 63 is fixed to the outer face of bar 40 immediately below the stop or lug 4i. This .is secured for limited adjustment up or down along bar 40 by means of a securing bolt 63', thus to make the release lever 60 more or less sensitive.

Assuming the parts of the. device tobe so constructed and assembled, and with the understanding that the tongs 20 have been properly applied to a log as in Fig.1 and that the log has been carried by the cable I6, to an unloading position, and has there been lowered to a position of rest on the cold deck, but that the parts of the present device are still in the normal load carrying relationship shown in Fig. 9 withoutv any slack as yet having been permitted in cable I6, the procedure to automatically effect the extraction or release of the tongs from the log, is as follows:

First, the operator of the hoisting engine causes about two feet of slack to be paid out in cable I6. After the first few inches of slack have been produced in-the cable, the bar I3 comes to rest by reason of its connection at the lower end with the tongs. The upper end. of bar I3 is at this time in contact with the upper end block 24 of the housing I9 and operates as a support for the housing. Then, as the additional slack is produced in the cable, the bar I2 moves downwardly into the housing Iii and the latch release bar 46, fixed thereto moved downwardly accordingly, ultimately causing the lug 4i thereon to pass beneath and beyond the lower end of the latch lever 54, whereupon the spring 56 causes the latch st to snap into holding contact with the top side of the stop, as seen in Fig. 10. It is here to be noted that a lost motion connection has been established between bars I2 and I3 Joy reason of their lugs I2a: and I33: being spaced apart to full extent.

It is necessary to insure proper operation of the present mechanism, that the housing It be maintained substantially in an upright position while this slack is being produced in the hoisting line. This is accomplished by means of a slack take-up mechanism that is shown best in flange 21 above the pulley block level, is ex- ;tended downwardly from the lug, passed about wheel tlflthen extended downwardly and wound, as shown in Fig.4,on a sleeve Ella: fixed on a :horizontal crossshaft II! that extends between and is revolubly supported by the flanges b-b. A conical drum H also is fixed on the cross shaft 76, and a cable 68:: has an end attached to the larger end of this drum and its other end deadended in a block 12 that is welded, to the upper end portion of bar l2. In this presentinstance the cable 683: isa continuation of cable 68 and ,both are dead ended inthe flange at the larger ,end ofdrum. l I. ,Thus the springti, at alltirnes.

A cable eifects the application of a downward pulling force on bar I2. However, this force is not sufficient to effect any upward lifting of the housing relative to bar I2.

It is shown in Figs. 4 and 6 that the arrangement of the conical drum on the shaft I0, and the attachment of cable 63 to the shaft I0 and cable 68st to drum is such that when the spring is permitted to contract, it operates through cable 88 to rotate the shaft Ill and drum in such direction that the cable 683: will be wound onto the conical drum from its larger toward its smaller end. This is to compensate for the decrease in power or pull of the spring as it gets shorter. This spring powered mechanism operates to pull the bar I2 downwardly thus to take in the slack as produced in the load lifting cable I6 after the bar I3 has been lowered into position of support by tongs or log, thus to maintain the housing It in that substantially upright position which is necessary for the engaging of the latch 44 with stop M. It is to be explained, however, that the tension of the spring is not suflicient to lift the housing I0 relative to bar I2 except under the conditions above mentioned.

With the engagement of the latch 44 with the bar stop 4|, a direct lifting connection is established between the bar 49 and the housing II), and about twelve inches of slack has been produced in the connection that had previously existed by reason of the engagement of the blocks 12m and ism on bars I2 and I3. The parts then are in position seen in Fig. 10.

With the parts in position of Fig. 10, the operator then causes the hoisting cable It to be wound in and the housing ID to be lifted through the holding connection effected by latch Y 44 and bar as. v, I

With the upward lifting of housing vID the tong release chain 30 becomes taut and before the lug I-Zm on bar I2 has moved upward into contact with lug I3, pulls .the jaw of the tong, to which it is attached, free of the log. a This action ultimately results in fullrelease of the other jaw of the tongs from the log and the tongs will swing free. I

It will here be mentioned that although not herein shown, it may be desirable and practical for. some operations that release chains 30 be applied to both jaws of the tongs. If so, the connection of the other jaw would be made in the same manner as already described.

When the tongs have been cleared fromone log, they may be carried in the open position to another, ready for application thereto, and, there reset for their automatic application to the log. The means for effecting the release or resetting ,of the tongs for such application to a log will now be described.

In Figs. 9 and 11 it is best shown that a cross-. shaft i5 extends horizontally through the flanges;

plate TI. Extended rotatably through the lower ends of the-levers lG- IS is a cross shaft 18. Op-

posite end portions of this shaft extend through 7 horizontal slots IQ-I9. in thefianges o-c to the outsides of the flanges .as in. Fig. 8, and welded .to these opposite end portions are lever arms .8i3'- 8Il that extend substantially horizontally through openings in flanges b-b and dr-.d,to

theopposite side of housing Iii Where they are i ieed by i eniale ee "P iwh q ei h ath-gin actuator" for the lateh rehzaseli'l'ever lill. "cross rod extends freelw*throughwperiings in the fianges ar- -a, as-observed in Eigi 8.

Fixed to the cross plate 'l'l' is' anupwardly and *otitwa-fdly directed -arm ii4, and=-'attached totthe 8 @rst. llhe'il, a aontmuamowenngosthe iiousmg l-Baas still supported by tlie eable throii'gh the E *latch mecliaiiism 'c'auses it to 'meiie Qid'wnw at dly :ealon'g barllfl. with the initial-doWnWardstravel bf hblismg to relative-to bar iawhe 'inner end ='-pol tionofam lever 9'4, whichat this ttm'e is e eiitending inwal dly through slot 9I,- will die contacted by the =-upper endfl of bar 3 and ithereby mamas upwardly and outwardly; thereby pullerids of lever --arms '--1B--16 and *the' cross rod .10 ingdownwardly on the togglel IiIIKageand caus- '18'-'mounted*thereby,- to the-outward-mositionfin which? they-are shown in Fig." 1 1.

Welded-iigidly to the'crossshaftl8, mediallly --o'f its ends, is an upwardly-extending -angi1lar,

iii tostraighten outgas from its fid lll lineposidflomoflfigntto the dotted line- :position. l-Ini this action of the toggle linkage, the lever arms 8Il-80 aresl1ifted; to: the ift; iinwreference to'showing in aendnof; leverifi nutwardlyxandzthereby eifecesdisrjzplacementbfothe lowenend of latohi44=irom-fstop $41 lTheslatoh wilhthen fbev momentarily're'tained inreleased position by: reason ofithe cross rod'cii I 22 remaziningcse'ated inc notch 160:1: :of: the lever.

:With release of latch :44, from -'istop iI 'the :housing E0 drops ireely downward to its 11111 sextent aa'elativetito the -bars I 2 and I 3 and 1 this causes 1 the =upper -e1id portion-1 of cam lever 90,

lever-is nivota-lly-mounted;between its ends, on across -pin" 95 -extended "between spaced ears BB-M onthe"adj-acent housing wall. "The upper end portion *of-lever -94 extends inwardly' through with the upper end portion of the relativelysta- -tionaryzabar 1L3, to rotateshaft 18 and swingthe lever arms 8Il-80-upwa1dly, thus to dispose the "crossrod fii above and in-the-olearof lever 50;

a-slot il I in the adjacent side wall of the housing @130 the =latch '-parts"- then assuming the: normal posi- I-Bforcontact with and-actuation-by the b ar i3. *As -will be--understoodby reference to Figss 9 and 11, the parts 16--I=6-and-'92- 92,'as pivotally j joined-by-the:-cross shaft 'mf form atoggie' link- *tionof 'F-ig. -9. Thenfithe operator w-indsin the *cable I 8 -a'n'cl *lifts the housing f through the ---media'cy of the inter-engaged lugs' IZ-dc and 'I 3a: of -thebars I2 and I3. "The' tongs will be lifted 'by a e thatmn'der-the influence of can1'='le er 93*&fid i'bar I'i-an'd they will automatically" close-on the "spring*85- wi=ll be -caused to break-outwardly and inwarmy-between thedifierent -positions shown in these views, and it is this action that'causes e the engaging and actuation of" the latch release 1 lever Gil -by the cross-rod 8 I lt is -to be understood that with the lifting or the housing i'Il by-eabie I6 after-the -'latch --bar 44 -has beenengagedwith-lug I I on' -bar =40,-'the' bar P3 drops "down in housing I 0 "from position =of Fig. lfl toth position shownin Fig. 11. With n45 this movement of bar I3, it disengages the-inner endofthe then--upwardl-y- 'directed lever 9 4: and the'tOg'gIe linkage is -permitted to .be:actuatedi by spring 85 -=to its outwar'd position as' in :FigJ 11. *Ihis causes the levers 8 0- 80 to- -pull': the cross rod -8 I a from above -to the inside Y of the upper end of the lever 60, -where it drops :down as in -Figilh to the levelzofithe notchittzciin theiever; thisbro i being permitted: by reason of :theerid portion 90 -of cam lever "90 then being lz-inluthe c'el1ar of the 'bar b3.

After the tongs havexbeen disengaged iiromia i log, athey are :carried: in: suspension-Eloy. :the :chain 30 in a laterally opening position,sreadyiiorrap- -plicationmto :another dog. The ;bars I;2.;andi I3, theiilatchv 44 and. thellatch- -r eleasing..-idevicesa ineluding theii toggle linkage tare 'irrthe :positio-ns :a relativeito each mtherlshowntin: iull linesqin Eig. ll. The'iautomatic :rielease 'o'f-the mechanisrmior :application. :of ithettongs, rand-:the resetting :of :partsrisxastfiollows:

'TWith thezopenntongs flowered tmand; properly .sidisposedrrelartive :tozztheiilog thatrisstobe nicked sup,zior-examplesas iinfEig.ij1b, or directly overtthe i log ='-if"itpissmall, the-hoist operator' carefu lly apays out thecable I6,-causing the-housing m to be "lowered' in'a manner to place the laterally:open ing-"tongs--in, gripping position. After thevtooth i of the-upper: ,iaw has caught in' the log; thebar log to which they' havebeen applied.

"Ifit' is'desiredp'a tag line, as atlflfldnifiig. 1, can be attached to the housing to control its posit-ion an'd- '-prevent its being rotated under in- MO =f1uence of the hoisting cable It and itstendency 'to' rotate under" load.

"Havingthusdescribedmy "invention, what I claim as newytherein, and desire to secure "by Letters Patent, is: 7

: l. In combinatiomfahoisting cable, a pair of load lifting *tongs, a jfhousing, a bar contained vertically therein andconnected at its'upper' end "to'jthe 'cable, another bar contained vertically in 'f thehousing and 'havingia load lifting. connec- "'tionat .its 'lower -:end with the tongs; said bars being "independently movable -endwise in 'the housing andrelative to :each other between an extended and a. retracted relations'hip, and said Qhousinghavingiimitedmovement along thebars,

"meansassociated"withithe bars foreflecting a loadlifting' c onnection'be'tween them-when fully extended relative to -each other "and providing slack in thesaid'load lifting connection when they are notiniiilly extended relationship, a tie -member connecting the-housing'with a jaw of the tongs for its eiitractien from a loa'd, and-latch "means operable' to eifecta lo'ad lifting connection "between-the first mentioned'cbar and said hous- ='ing when thesaid' bars are in a slack producing TGIEtiOIl-Ship, through WFii'Ch -DLlH 'Of the hoisting cable cambe'applied to saidjaw ot-the tongs for itsextraction.

i In'cornbination; a pair of load lift'ing tongs, "a hoisting cable, a housing, a :pair ofbars ""l mmounte'di irr tliehousing for endwise "movement therei-n relative t'o' eachother and'i for telescopic -'movement into: and from the: housing: independ- -en'tl'y 'of each-'other; the -first of saidbars having its-flipper e'ndcz 'iorti'o'n extended upwardly "from "3!, assupporte'dby theclevises'fl I9;"cornes-to the housing and connected"toi'thehoistingfcable,

9 the second of said bars having its lower end portion extended downwardly from the housing and having a connection with the tongs, and said bars having a load supporting connection between them when fully extended relative to each other, a latch stop on the upper bar, a latch lever mounted on the housing and operable to engage the latch stop to lock the upper bar in a position fully telescoped in the housing, providing slack in the load lifting connection, and a tie member joining the housing and one jaw of the tongs for the extraction of that jaw from an engaged load by pull of the hoisting cable applied through the said tie member and the upper bar and housing as thus latched together.

3. A combination as recited in claim 2 including a latch release mechanism operable through the mediacy of the second of said bars by the telescoping of said bar into the housing.

4. In combination, a pair of load lifting tongs, a hoisting cable, a housing, a pair of parallel bars overlapped one with the other in said housing and telescopically movable into and from the same; the first of said bars having its upper end portion extended upwardly from the housing and connected to the said hoisting cable; the second of said bars having its lower end portion extended downwardly from the housing and having a load supporting connection with the tongs, lugs on the inner ends of the bars adapted to engage one with the other to provide a load supporting connection between the bars when they are fully extended relative to each other and disengageable from each other to provide slack in the connection between cable and tongs when the bars are not fully extended relative to each other, said housing having limited movement along the bars when they are fully extended relative to each other, a latch stop on the first bar and a latch lever on the housing operable to engage the stop when the said first bar is substantially telescoped within the housing, to lock the housing to the bar, and a chain connecting the housing and a jaw of the tongs, through which an extracting pull can be applied by the cable to the jaw through the said first bar and housing as thus latched together and while there is a slack condition in the bar connection.

5. A combination as recited in claim 4 including a latch lever disengaging mechanism mounted on the housing, and operable by the second bar when moved from a position extended from the housing to a position telescoped therein.

6. Apparatus as recited in claim 4 including a spring attached under tension to the cable and housing and operable to take up slack as produced in the hoisting cable while the housing is supported through the mediacy of the second bar, and wherein the said chain is of a length that, with the tong to which it is attached secured in a load, it will retain the said housing in its lowered position on the extended bars.

7. In combination, a pair of load lifting tongs, a hoisting cable, a tubular housing, a pair of parallel bars that are overlapped one with the other in said housing and independently telescopically movable therein; the first of said bars having its upper end portion extended from the housing and joined with said hoisting cable, the second of said bars having a load lifting connection at its lower end with the tongs, stops on the inner ends of the bars adapted to be engaged to provide a load supporting connection between the bars when they are fully extended relative to each other and disengageable from each other to provide slack in the load lifting connection, said housing having limited up and down movement along the bars, when they are extended relative to each other and no movement when both are fully telescoped thereinto, a latch bar fixed to the upper end of the first bar and extended downwardly along the housing, a stop on said latch bar, a latch lever pivoted on the housing, yieldable means urging the latch lever against the bar to urge it to position to engage with the said stop upon the complete telescoping of the first bar into the housing, a chain joining the housing and one jaw of the tong for the extraction of the jaw from a load, and a spring attached under tension to the housing and first bar to draw slack in the bar connection when the cable is paid out for a latch setting operation and the housing is supported through the said second bar.

8. A combination as recited in claim 7 including a latch release lever that is mounted pivotally between its ends on the movable end of the said latch lever; said release lever having one end portion thereof extended beyond the end of the latch lever to engage a fulcrum member, and there being other lever mechanism mounted on the housing and. operable against the other end of the said release lever for the disengaging of the latch lever from the stop; said other lever mechanism being disposed for actuation by the said second bar in its upward travel in the housing.

9. In combination, a pair of load lifting tongs, a hoisting cable, a housing, a pair of parallel bars overlapped one with the other in said housing and independently telescopically movable therein; the first of said bars having its upper end portion extended upwardly from the housing and connected to the said hoisting cable; the second of said bars having its lower end portion extended downwardly from the housing and having a load supporting connection with the tongs, lugs on the inner ends of the bars adapted to engage one with the other to provide a load supporting connection between the bars when fully extended relative to each other, and disengageable from each other to provide slack in the connection between cable and tongs when the bars are not fully extended relative to each other, said housing having limited movement on the bars when fully extended relative to each other, and a latch mechanism associated with the housing and the first of said bars for locking the first bar fully telescoped in the housing while permitting the second bar to have movement into and from the housing, and a latch disengaging mechanism on the housing operable from a retracted to an extended position to disengage the latch under influence of the said second bar incident to its being lifted from an extended position to a position telescoped within the housing.

10. A combination as in claim 9 including also, a spring actuated means operable under control of the said second bar to return the latch disengaging mechanism to its retracted position.

ERNEST E. ECKSTEIN.

No references cited.

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