US2636768A - Brick stack handling fork - Google Patents

Description

l April 28, 1953 F. T. HANSEN BRICK STACK HANDLING FORK 5 Sheets-Sheet l Filed OCT.. 17. 1949 April 28, 1953 F. T. HANSEN 2,635,768

BRICK STACK HANDLING FORK Filed Oct. 17, 1949 5 Sheets-Sheet 2 FIG-J' INVENTOR. FPED T//HA/SEN Apnl 28, 1953 F. T. HANSEN 2,635,768

BRICK STACK HANDLING FORK Filed Oct. 17, 1949 5 Sheets-Sheet 3 F. T. HANSEN BRICK STACK HANDLING FORK April 2s, 1953 5 Sheets-Sheet 4 Filed Oct. 1'7, 1949 QGD m. w m m F. T. HANSEN BRI'CK STACK HANDLING FORK April 28, 1953 5 Sheets-Sheet 5 Filed Oct. 17. 1949 INVENTOR. F/PED 7.' HANSEN ZOO Patented Apr. 28, 1953 En sli-'mias Param osica BRICK STAGE HANDIiIlSTQaeFORK;

Ered".T.Hnsen, GreenBay, W is.

Applicatiunbtdben 17, 1949; v Serial No;` 121%6'56,

23 Claims. .li

Myv invention re]ates;to,improvements in. brick -lfiaridlingi-.imita` `and naatticulanly to .imm-.over mentar. in: uan brick. handling: fork;y Ofi ai type that ia `adaptedto; handle.; at pile; ci; ,lari-olie `stacked upwinsconformity with: ai prearranged plan and witlflzunii'orin spaces?,between base courses intol whioiif times, including-j clamping devices i automatically;actuate @"qibrwthe:weightofcthe-load.

may. 'liepitojectled 'intrasaithaparece` to;carry,A the superpu'sedload,and also.fto pick up and carry along; with` the2 superinenmbent.. blicke` the; hase i coalsesribw ineanaoiiahorizontall grinoinaacton causedi b5 i clamping-devices, Asaxthat thefstaci. may be `handled and;loweredinto.ipositionfrand the titres Withdrawniwithout disturbing; the.` arf- `rangementthereof;

VBrion art; hriclizstaeli-:handling forksembody aritension or compression snilnggfon halancingpthe welght'fei `thee. di; Said; spiringg` constructions necessarily `ieduireaar stiffnsprine, a; spring; with ai lng-i1 spring; :constan-L .toi` balance: the dead `'v'veigizittof :the heauyusteeliiorleioonstruction `re:- quired by the work 4to be done. Ar la; cesultnthere- .orti only' larae; 'sunernosed loads :are capable of stretchingtlrre; s' sufciently to4 furnish `the measure of initialll eralidisplacementqoithe ela'mpingf devices necessary to, Contact the base courses. This condition rules outti-the-handling of) iractiona'li capacity `loa-ris. The. inherent nature;V character; and .operi-maion-` oi a spring lihalancing: construction: prevents its successful application; ta' iriaotonai loads-i hecauseit `re,n

quires a considerable parasite load to expand and extend; the;` clamping devices into .i Contact .i `with :thaaiaase: rowsoo", .brick `beforegripping` pressure :can bei; applied., The-spring constructions, exi,- pand i theegrippersvstep `hygsteizi iasfparasite .load is A progressively appliedtoystretch thegspring until contanti iszifnallyf marley with ,the loriclf,l andL the device isonly,:thenirea'dygto apply Dressure -to-.the brick;

It should; benefici thatitiie :parasiteioadcf `the springconstrnctions r, continues; to be: augmented `as `the spring.T is: .f ur-therftensioned: during; the pressure =c1elivery= staeeaor; until theiforle` reaches a `pressure` .stop- ;zeieirientA or :otherxoperational adiustznent.

Mr.; invention; on the; other `hand provides a :gramme-force- (counterweight) that` is.` capableI ,of `nicely` coun-terhalancingz theiforkpropen. which is=^ soyeltebalanced: by theV application, of faz, ivery small load; The over-halarminegil results in the `forthwith i expansion ,of thefgrippers intorcontact with the brick, and is therefore immediately readyftofanplyp-ressureethereto,therehyeliminatv :ingmarasitedoam 1 lil tozaocomnlishfa more iposi-tiifeand tml-retraction ci; theverlopen,y this would#dnecessarily;increase an already burdensome parasite load o i Mm counterfweiaht on 'the other hande. can ,be made to f slightly over-balance. the,V fork,. thereby pravidingan iexcessfvforce applicable tito. iorceiully and 4,nositiuely/ retract tha gripping:` mechanism pto its fullest.

furthen claiminox/elm` in animproved .gripper mechanism thatV for all,` practical" purposes ,i has onlycneidegree, of freedom, that is, lateral 'tlirust .only-asfdistinguished `from.the,prior art'. which disclosesmechanismsfthathave a damagingjlon'- Y gitudinal thrusticomponentalbng with ,tlelateraji -thrust.. i

My toggle action: gripping mechanism is ydesgned. to.. `operate at its. maximum thrust capacity.

It is an objeobofymy. invention to'providea brick stack handling frk'tliat will liajrid'lerfractional capacitylads It Ais another objectJ of "myinventionI tof" prolvidenovel. means for balancing -a `brick 'stack handling. ffork..'that` makes itcapableoi handling frac-tional capacity loads.

It isstill. another object of my inventiomto provide means for balancinga'ubrircldsta'ckfhand1inaor1-v that allows the. gripping mechanism i to.. hafrthwi'tli extendedintbrcontaot with the base course OVbricKS'upon theapplicaticmloflafn incremental over-balancingload.

It' is' yet' ano'tlenobjectof"invention to provide meansfor'balarming"a:l ldriekstack 'lian'- dling fork that.allowsthey working load -t'o be Wholly and completely `devoted tothe -generation 'w oflaiteraljpressure forthegrippers.

Itis a further object'oniyinventioi'vtcrM profvide means for balancing a brick sta-ci: handling `fdr-l; thatA eliminates the'parajsite loadfreouired to.. "hiring thfe 'grippersr into'v operable' position apressurestop element:

It is a still further object of my invention to provide gravity balancing means for a -brck stack handling fork.

It yet is a further object of my invention to provide gravity balancing means and lever linkage means associated therewith, having a movable fulcrum, for balancing a brick stack handling fork.

It is another object of my invention to provide a gripping mechanism for a brick stack handlingfork that for all practical purposes has one degree of freedom, that is, lateral thrust only.

It is still another object of my invention to provide a gripping mechanism for `a brick stack handling fork that eliminates damaging longitudinal thrust which results in the rapid wearmg of the gripper shoes, and possible displacement of the base brick which is cumulative.

Itis yet another object of my invention to provide a grip-ping mechanism for a `brick stack handling fork that is designed to operate at its maximum thrust capacity.

It is a further object of my invention to pro- Vide a gripping mechanism for a brick stack handling fork that reduces to a minimum Ithe possib bility of inoperability due to jamming of the parts one against the other,or to the accumulatwn therebetween of foreign matter.

' It is a still further obiect of my invention to provide a gripping mechanism for a brick stack handling fork that is self cleaning.

It is yet a further object of my invention to provide a gripping mechanism for a brick stack handling fork that allows the use of a highly frictional shoe facing, such as rubber, for better gripping effect.

It is a nal object of my invention to provide a gripping mechanism that contains a minimum number of movable parts, that requires a minimum of machining, and is easy to fabricate and assemble.

Other objects and many of the attendant advantages of my invention Will be readily appreciated as the same becomes better understood by reference to the following detailed deinner tines taken along broken line ll--i of Fig. 2, .showing the top flange removed and showing the brick gripping mechanism in retracted position,

Fig. 5 shows the tine of Fig. 4 in expanded position,

Fig. 6 is an end View of the rocker shaft and an associated spring abutment element in various positional phases,

. Fig. 7 is a cross-sectional view of one of the .tines taken along line 'I-l of Fig. 5,

. Fig. 8 is a cross-sectional view of one of theA tines taken along line 8--8 of Fig. 5, and

Fig. 9 is an exploded isometric view of one of the tines showing the gripping mechanism in detail.

Fig. 10 is a schematic representation illustrating the general principles of the invention.

`The weight is shown out of its normal position for clearness of representation.

Fig. 11 is an isometric view showing in partic- 75 4 ular the lever system in its relat1on to the frame, saddle, and weight.

Referring now to the drawings, wherein for the purpose of illustration, is shown a preferred embodiment of my invention, the reference numeral I designates an elongated base bar to which is secured, as by means of bolts 2 and II, a plurality of equally spaced upright bars 3 tied together at their tops by means of an angle iron 4 welded thereto, forming there together an'upstanding rectangular gridiron frame, which is mounted on a base plate 5 and is secured thereto as by welding.

The inner tines 6 consists of an H-beam having a face plate 1 welded transversely of the tines to one end of each of said tines. These tine assemblies are secured to the bottom portion of the base plate I as by bolts 8, Fig. 1, the H-beam being disposed so that its web is vertical. 1t is to be noted that bolts 2 also act to secure the face plates 'I to the upright bars 3. The two outer tines 9, Fig. 1, are of modied H-beam construction in that each has the outside portions of their flanges removed, resulting in only one gripper mechanism being accommodated along the inside. only of said tines, as distinguished from each of the inner tines which have a gripper mechanismalong bothsides there- 0I. As the gripping mechanisms along tne sides of all the tines are constructed alike, a description of one gripping mechanism or the corresponding components thereof will apply to all.

Arranged in the beam recess or space bounded by the top flange I2, bottom flange I3, and web I4 of H-beam Ii is the gripper mechanism comprismg a pull bar I5, an elongated channel shoe retaining member I6, gripper shoes I'I, toggle links I8 for engaging the shoe retainer to the pull bar, and an oscillatable link guide I9 for controlling the movement of the shoe retainer for reciprocation transversely of the tine. See Figs. 9, 8 and 7.

The pull bar I5 is disposed adjacent to the underside of top flange Iz and the web I4, and is supported in that position by a channel section 2l at its rear end, and a plate guide 22 at its front end.

The channel section 2I has its web portion welded or otherwise secured to the underside of said pull bar, and its leg-like flanges in sliding engagement with the top surface of tine flange I3.

The plate guide 22 is provided with side flanges 23 which abuttingly engage with the underside of tine flange I2 to receive the front end of pull bar I5 in sliding engagement therebetween. rIhe web I4 of tine 6 is cut away at its front end,

as at 24, to accommodate the insertion and placement of plate guide 22. The plate guide is provided with an inclined slot 25 for the reception vand removal of sand, grit, or other foreign matter that may foul the plate guideway. Such foreign material as might find its way into the plate guideway would be delivered to said slot for removal by the normal reciprocating operations of the pull bar head. This results in a self cleaning construction. Longitudinally, the plate guide is of a length that will support the pull bar throughout its travel. The plate guide 22 is held in its operative position by means of a cap screw 26 supported byV the closure plate 21 Welded across the front or head end of tines 6.

Disposed beneath said'plate guide 22, and secured to said closure plate 21 by means of cap Fig. 6 shows an end View of the rocker shaft and its associated spring abutment block 6| in the retracted position 13, and the expanded position 14.

To each end of the square rocker shaft 5| is secured a crank arm which is connected to a pull-rod 16 through means of a clevis 11 which is welded to the lower end thereof, and which is pin connected to said crank arm by means of pin 18. The upper end of saidpull rod 16 is provided with an eye 19 threadedly engaged with said pull-rod for adjustment, and pin connected to saddle bar 8| through means of pin 82. See Fig. 2.

Said saddle bar 8| consists of an angle iron horizontally disposed near the upper end of the gridiron frame. One leg of the angle iron is horizontally positioned; the other leg, disposed outwardly of the frame, extends downwardly. The function of the saddle 8| is to engage with the lifting plate of a lifting truck (not shown) and be carried thereby. To each end of the saddle are secured additional leg plates 83 to support the pins 82 in a simple beam manner.

Pending plate guides 84 and 85 are secured to the horizontal portion of the saddle as by welding, and serve to guide the lifting plate of the lifting truck (not shown) into the saddle for engagement therewith. The lower ends of said guides 84 and 85 are curved rearwardly as at 90, Fig. 2, to stabilize the saddle in erect position when the lifting plate (not shown) engages therewith. The distance between the outer legs of the saddle and the guide plates is of a measure providing sufficient clearance to allow a tilted p lifting plate to enter therebetween and engage with the saddle.

Mounted on said saddle, near the ends thereof, are base blocks 86 and 81 secured thereto as by welding or otherwise. and 85 have their upper ends extended so as to abut the side faces of said blocks, and are welded thereto so as to provide greater strength of securement.

Yokes 88 and 89 are mounted on said blocks to receive therethrough the head-ends of paired shoulder lugs 9| and 92 that are secured to the top of tie bar 4 as by welding. The head ends of said lugs have downwardly projecting portions 93 and 94 that have journalled therein pins 95 i and 96 rotatably supporting rollers 91 and 98, respectively. Said roller laterally supports the saddle, and guides it in its up and down movements. The spaced relation between the follower shoulder lugs 9| and 92 and the base blocks 86 after contact therewith the required pressure yof the shoes against the bricks is slowly generated and later controlled. Said take-up distance may be varied by adjustable means such as shims. After the base blocks have engaged the shoulder lugs, the gripper pressure against the bricks ceases to increase, remains constant, and the assembly of the gridiron frame with its attached tines is bodily lifted along with the saddle structure, by a lifting plate (not shown). It is obvious that a small load of bricks upon the tines functions to resist the initial lifting force exerted by the lifting plate, thereby holding the fork frame immobile while the saddle structure, driven by the lifting plate, negotiatesthe take-up dis- The plate guides 84 tance; resulting in an automatic actuation of the gripper mechanism and the generation of the .lateral pressure required to grip the bricks as a consequence of the restraining load.

The yokes 88 and 89 are xed to the base blocks 86 and 81 as by paired bolts 99, |0|, |02 and |03.

A pair of crossed lever arms |04 and |05 are pivotally mounted on pins |06 and |01 which are fixed in guide plates 84 and 85, respectively.

The upper end portions of said lever arms |04 and |05 are rollingly engaged with rollers |08 and |09 rotatably mounted on pins I|| and ||2 which are xed to the outer upright bars 3, respectively.

The lower ends of said lever arms |04 and |05 are link connected to a counterweight ||3 through means of links ||4 and ||5, respectively, the link connections being off-set one in relation to the other to allow the lever arms to move in separate planes.

The weight of the gravity mass |3 on one end of the lever system shown is approximately onethird of the weight of the fork so as to decidedly over-balance the weight of the fork structure acting on the other end of said lever arms through rollers |08 and |09, the fulcrums being pins |06 and |01. The pivots |06 and |01 are disposed in the lever bars so that the effort arm portions of the bars are approximately three times the length of the resistance arm portions of the bars.

It is obvious that means other than a lever system can be used between the weight and the fork, such as a wheel and axle system, or pulley system, or a train of gears.

Bearing rollers I6, rotatably mounted on pins I1 journalled in arms l|8 secured to the upright members 3 as by welding, are provided for lateral bearing support against the engaged lifting plate (not shown) Side sway lugs ||9 and |2| having rearwardly extending flanges |22 and |23 are fixed to the outer upright bars 3 to receive the lifting plate therebetween and restrain the sidesway thereof. Said iianges also serve as stop members with which the downwardly moving counterweight engages when the gripping mechanism is completely retracted thereby relieving said mechanism of damaging stresses.

The front face of the gridiron frame is provided with guard members consisting of vertically disposed angle irons |24 having the edges of one of their legs welded to the adjacent upright bars 3 and presenting the flat face of the other leg, forward. The bottom portions of said guard members overlay the base bar I and cover the bolts the upper portions of said guard members are tied together with an angle iron |25 as by welding or otherwise.

Fig. l0 discloses a schematic representation of the invention wherein the reference numerals of the preceding gures are used to denote equivagripper assembly 20| that is connected to the bell-crank by means of pivot 58. Saddle means 8|, adapted to receive the lifting plate of a lifting truck (not shown), is connected to the other end of the bell-crank through means of pull-rod 1.6::` At plateft; rigidlyrxed-torasaidsaridlelsupe` ports af-.leverwarm 1051i through, meanszfof fulcrum pivotl DS. This 4fulcruml pivot .is movable: up` and dovvnf with the saddle andfitsassociatedpull-rod 16; A counterweiglit/` IIS isattached to` one end ofthe lever arm |05; While: the other; end reacts against a roller I03"pivotally'mountedfon therfork: member 3 through means of pivot I I I Themagntude on the; counterweiglitr I It@Y isapreferablyof al meas-ure:` tozslightiy;` overbalance the- Weight of, the. fork. propert` supporteda` ont the-1 otheru endA of theleverrarml H: This; overba'lancing provides attalsei-'up spaced relations:202,betweenthe7 saddle 3:1; andthe shoulder member QI. Itjfs obvious from this simplified llustrationthatlwhen af lift'- ing foroeiE" is; applied underthei'saddle thea-oven balancing: effect-#aofi` thef counterweight maintains thetakeeuprspaced. relation' 2112y between the-saddlesandf'forkzproper; andA said saddle and associati,d ed lforlrlzarezpi-ckmn-asa unit.` When the tinesf are@slippedfunderca prearrangedrbricls.. stack,` the load thereof resists upward movement iofthe fork` proper;` andra furthereliftingt movement' applied under Athe saddley 18 I resultssinfthe saddle assemblvi being:,movediulpwardly :relatvetovthe ,loaded and; held-fast forli; ,untilthe-v sa'didle 81 solidly contactszthe:shoulderrmember :9 I: after whclrboth` tlevforl: and; 1saddle assemblies` are lifted iniunion: Duringfzthe: taker-upf` movement;` that-r ist-whenthesadd'le f assembly* ist beingz' moved relative? to`V the fork; proper; thegrippen assembliesfz d are? beingr actuatedinteextendedegripping positionyagainst theflbase kooru'set ofbriclo: Whenf the` loadboffbrick iste be setedown: thelittingplate acting through force F is slowly lowered untlltlelb'aselfot'briok touch tlliezfgroundi 'andthe fol-'lr'` is'v relieved of the load; stresses. The liftingpla-teis continued to, be: slightly=` lowered-2 resulting t in, saddley moving downwardly4 relativemtotlie'forllty tlerebsY restoringtthe take-upspaced relation 201i During `this downward movement; the gravity-'f force othe counterweight IIi3l and thei deadweiglltf of`tli`e saddle'4 `assemlzlly-` `provide the'- forcenecessary toy nositivelyretractthergripperiassemblies 20`I The tines are now-withdrawn from" un'dentlfiev brick" stack by a rearward movement of the truck; and the lifting truck andthe'- fork' are now readyv to repeat the operationen anothenpile'of bricks:

Operation. When the. fork is" to'be used;` a 1i`1t= ingtruek liavingjaiv lifting plate f (noti-shown) approaches the fork, tilts the plate' slightlyforward and engagesthesaddlel to supportit. the" lifting plateis., raisedlthegpcomplei,IK ZJSSBIIIF blv,` comprising` the fork.; frame., and`tines,;. structureythesaddle structure,,and` the intervening. counterweightsstructure,.is. bodily, liftedlfrom. the

ground.` Saidsubassembles maintain their oparable relative positionsl'one, to the `other,asshown in Figs. 1 and 2 because of the acting forcesthereon, providedby the'counterweig-ht Thercounterweight.; tends to maintain the.` takeeupy distance, andl `when not acteduponl-by;some1 externalforce such-assafbriekloadgthefforkt does maintain 1kthat normal spaced` relationabetweenl the.. frame l and ther-saddle Stop-members I-22 and. I23control thatarelativefposition. Stop members I22 andI I2 agaalso; function to absorb :shock.jandfrelieverthe gripper assemblylonwear and tearr;resulting` from' the gripper mechanism being fully and violently retractodagainsttheswebsL42 Thef pile'. otr brclezto: b'errasedf, and: transported isfizsupported; on. ground; rowsorf basezcoursesf of bricks; Each; ofisad;` rowsfor courses consists of tandem@ arrangedy pairedl` bricksr @resting fonrltheir side: edges;- andsibetvreen `.said rows` are `provided openings: I When the-,pilefisrdto bei moved.y theforkf ort-the littngz'truolzs torberased", ,lowered orfsde-shifti ed until it:` aligns: With-tl the` openings, and isA `then slid into theropeningsbmaxforwardmovement of thextruck.

As the-slitting: truck through its, lifting plate commences: toy applyV a. raising; force to the bottomfofxthe brick; pile, the loaden thetines resistsfthe ,initialllitting forces however; the movabl'e `1saddle-is:slov\rlvmoved. upwardly by the lifting plate; relativeltothetforltzframe, within the load superimposedony the,tines,as.Wellasthe` ground'y rowsof..bricks,arerasedbodily `for trans-l portation.

During the takefup movement, ,thegcounterweight tI-I 3 is raised fromits .Iowermost' position to its, uppermost., position through.. means of its lever connection .tol the movable saddle .and its lever. engagement., with reaction roller IIJBand' llllxed.' tothe immobile forli frame. The rais"-` ingfo the Weight toits, uppermost position'. gives to. itllthe potentialgravityV energyl necessary to retractthelgripping mechanism; 4as; hereinlater described".4

The. gripper; mechanism" is actuated through means-ofthe pullbarl 5 linked-tothe rocker shaft 5I by means of eye-bolt 41, compression springs Giraud"y @Stabutment Sil, andbraclets: BIifIandTS'I. A'sthe saddle -is-` moved"tlirough theftake-updisrod lo'aotuatestherockershaftcloclrwise through y means-or cranlrarm 'i513' Thislclocltwisemotion outwardagainst the bricksrandtgeneratesi anendiwise pressure` thereagainstl. which. increases:` in'- definitely` as ther, toggle link'. approaches-A -a position atfriglit'anglesto thefpull.` bar.y Itr isitobe not'ed that".` `for all.. practical` purposes"` the shoe retaining member.hasonlyoi'x'e` degreeof motiom namely; outwardly,. guided by oscillatable` link guide i9: Itslongitudinalmotion isfrestrained bvsaidsamelinksguide,1.9;I

Whew ther-load; israbouty to; bedeposited ati its destination; the:` liftingi'plate and thea complete As` al result thereof'V is still at its upper limit of the take-up distance, and a lifting force necessary to generate the required lateral pressure on the bricks is still being applied by the lifting plate and resisted by the load. To complete the act of deposition, the lifting plate is continued to be lowered, and the associated saddle lowers with it, while the fork proper remains immobile, being urged against the bottom of the` brick pile by forces resulting from the counterweight. As the saddle retracts from its upper limit of the take-up distance there results a diminishing lateral pressure against the bricks until the pressure is reduced to Zero.

As the lifting plate and its supported saddle is lowered still further, the gravity force of the counterweight bearing on the saddle, through means of the lever linkage and pins f06 and |01, forcefully urges the saddle downwardly relative to the fork resulting in a positive retraction of the gripping mechanism communicated through the pull rod 'IE and appurtenant linkage.

When the counterweight reaches stop lugs |22 and 123 the retraction is complete. Thereafter the complete fork assembly comprising the fork frame structure, the saddle structure, and the intervening counterweight structure is bodily lowered from engagement with the bottom of the brick pile, by a further lowering of the lifting plate, and the tines withdrawn by a rearward movement of the truck. The lifting truck and the attached fork are now ready to repeat the operation on another pile of bricks.

It is the Yfunction of my invention to provide a brick stack handling fork, of the type that has the grippers actuated by the weight of the load, that will handle fractional capacity loads, that eliminate parasite load, that actuates the grippers against the bricks forthwith, that embodies gravity balancing means, that provides a gripping mechanism with one degree of freedom (lateral thrust only), that provides a gripping mechanism that will not jam and is self cleaning, and that allows the use of highly frictional shoe facing.

It should be understood of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and the scope of the invention as setforth in the appended claims.

What is claimed is:

l, A brick stack handling fork, comprising: a frame having a plurality of tines, projecting shoulder means, and roller means rotatably mounted on said frame; proiectable mechanism carried by said tines for gripping and holding bricks therebetween, said mechanism being normally in a retracted position; a movable saddle structure adapted for engagement with said shoulder means, and adapted to receive a lifting member; means connecting said saddle and said projectable mechanism for actuating said projectable mechanism responsive to movement of said saddle; a counterweight; a pair of lever arms disposed cross-wise f each other, pivotly connected to said saddle, rollingly engaged with said roller means, and link-connected to said counterweight, operative to slightly overbalance` said frame and dispose said shoulder and saddle in a take-up spaced relation, whereby, under load conditions, the initial lifting movement applied to the saddle by a lifting member automatically expands the gripping mechanism into immediate engagement with the brick, generates lateral pressure for gripping and holding the brick, and thereafter engaging the saddle with the shoulder means for 'bodily lifting the fork and its superposedload and during which interval the counterweight having been raised in readiness to retract the gripping mechanism when the fork is unloaded.

2. A brick stack handling fork, comprising: a frame having a plurality of tines; an extendable structure carried by said tines for gripping brick therebetween; a movable saddle structure adapted for engagement with said frame and adapted to receive lifting means; means connecting said saddle and said gripping structure operative to actuate said gripping structure responsive to movement of said saddle; a gravity mass; lever means connecting said frame, said saddle structure and said mass, operable to overbalance said frame and dispose said frame and saddle in a take-up spaced relation; and stop means to limit said spaced relation.

3. A brick stack handling fork, comprising: a frame having a plurality of tines rigidly fixed thereto for lifting; an expandable mechanism carried by said tines coactable with corresponding mechanism on adjacent tines for gripping and holding brick therebetween; movable saddle means for actuating said gripping mechanism, adapted for engagement with said frame; a counterweight; and lever means connecting said frame, said saddle means, and said counterweight, operable to overbalance said frame and establish a take-up spaced relation between said saddle r means and said frame.

4. A brick stack handling fork, comprising: a frame having a plurality of tines rigidly connected thereto for lifting; gripping mechanism carried by said tines coactable with corresponding mechanism on adjacent tines for gripping and holding bricks therebetween; movable saddle means for actuating said gripping mechanism; a counterweight; and lever means with reactions on said frame, on said saddle means, and 4on said counterweight, operable to overbalance said frame.

5. |The apparatus of claim 4 wherein the lever means comprise a pair of levers disposed crosswise of each other.

6. The apparatus of claim 4 wherein the lever means is pivotly mounted on said movable saddle means.

7. The apparatus of claim 4 wherein the lever means is pivotly connected to said mass.

8. 'l'he apparatus of claim 4 and a roller rotatably mounted on said frame, and wherein the lever means is rollingly engaged with said roller.

9. The apparatus of claim 4 and a stop secured to said frame to arrest the downward travel of said mass.

10. A brick stack handling fork, comprising: a frame having a plurality of tines rigidly xed thereto for lifting; extendable mechanism carried by said tines coactable with corresponding mechanism on adjacent tines for gripping bricks; movable means for actuating said extendable mechanism; a gravity mass; and mechanical means connecting said frame, said actuating means, and said mass, operable to balance said frame.

11. A brick stack handling fork, comprising: a frame having a plurality of tines rigidly connected thereto for lifting; extendable means carried by said tines coactablc with corresponding extendable means on adjacent tines for gripping bricks; movable means for actuating said extendable means; a gravity mass; and means connecting said frame, said actuating means, and said mass, operable to balance said frame.

12. A brick stack handling fork, comprising: a frame having a plurality of tines rigidly xed thereto for lifting; brick gripping structure cari ried by said tines coactable with corresponding gripping structure on adjacent tines; movable means for actuating said brick gripping structure; a gravity mass; and means connecting said frame, said actuating means, and said mass, operable to balance said frame.

13. In a brick stack handling fork having a frame and a plurality of load supporting tines rigidly fixed thereto, retractile brick gripping means on said tines coactable with corresponding gripping means on adjacent tines, a gravity mass associated with said frame and said gripping means operative to actuate said gripping means.

le. 1n a brick stack handling fork: spaced tines, each tine having thereon an axially reciprocable pull bar; a shoe carrying member; linkage means having its ends pivotally connected to said bar and said member, respectively, in toggle joint arrangement; and guide means engaging said tine and said member, operative to guide the member outwardly of said tine.

15.1n a brick stack handling fork: spaced 'tines, each tine having thereon an axially movable pull bar; a shoe mounting member; link means having one end pivotally connected to said bar and the other end pivotally connected to said member, in toggle joint arrangement; and mechanical guide means connecting with said tine and said member, operative to guide the member' laterally of said tine.

16. In a brick stack handling fork: spaced tines, each tine having thereon an axially movable pull bar; guide means for said bar; a shoe supporting member; a link having its ends pivotally connected to said bar and said member, respectively, in toggle joint arrangement; and a link having its ends pivotally connected to said tine and said member, operative to guide the member transversely of the tine.

17. In a brick stack handling fork: spaced tines, each tine having thereon an axially reciprocable pull bar; guide means for said bar; a shoe carrying member disposed under said bar; a link having its ends pivotally connected to said bar and said member, respectively, in toggle joint arrangement; and an oscillatable link having its ends pivotally connected to said tine and said member, respectively, operative to guide the member laterally of the tine.

18. In a brick stack handling fork: spaced H-bearn tines, each tine having an axially reciprocable pull bar in each beam recess thereof, disposed adjacent the beam web and the upper flange; at least one bracket depending from said bar; a toggle link having one end pivotally mounted on said bracket; a channel beam disposed under said pull bar with its web adjacent the web of the H-beam, the other end of said link being pivotally connected across the channel flanges in toggle joint arrangement with said bar, said channel web having openings therein to accommodate the bracket and toggle link; and an oscillatable link at one end of the tine, having its ends pivotally connected to said tine and said channel beam, operative to guide the channel beam transversely of the tine.

19. In a brick stack handling fork: spaced .Li-beam tines, each tine having an axially reciprocable pull bar in each beam recess thereof, disposed adjacent the beam web and the upper ange; means for guiding said bar; brackets depending from said bar; a toggle link for each bracket, having one end pivotally supported on said bracket; a channel beam disposed under said pull bar with its web adjacent the web of the H-beam, the other end of said link being pivotally connected across the channel ilanges in toggle joint arrangement with said bar and operative to expand responsive to a rearward force applied to said bar, said channel web having openings therein to accommodate the bracket and the link; and an oscillatable link at the head .end of the tine, having one end pivotally connected to said tine, and the other end pivotally connected to said channel beam, operative to guide the channel beam transversely of the tine.

20. The apparatus described in claim 14; and gripper shoes; means slidably supporting said shoes on said shoe carrying member; and a compression spring between said shoe and said member, operative to urge the shoe away from the member.

21. The apparatus described in claim 16; and gripper shoes; means slidably supporting said shoes on said shoe carrying member; and a compression spring between said shoe and said member, operative to urge the shoe away from the member.

22. The apparatus described in claim 18 and an elongated shoe receivable between the channel flanges, said shoe having a frictional resilient facing; means slidably supporting said shoe on said channel web; and compression spring means between said shoe and said web operative to urge the shoe outwardly of the web.

23. The apparatus described in claim 19 and elongated stiff shoes receivable between the channel flanges, said shoes having rubber faces bonded thereon; means slidably supporting said shoes on said channel web; and spring means between said shoes and said web operative to urge the shoes outwardly of said web.

FRED T. HANSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 679,440 Tempest July 30, 1901 956,330 Fritsch Apr. 26, 1910 1,051,001 Peneld Jan. 21, 1913 2,311,084 Redler Feb. 16, 1943

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