US2620930A - Adjustable object handling cradle - Google Patents

Description

Dec 9, 1952 A. s. MULLGARDT 2,620,930

ADJUSTABLE OBJECT HANDLING CRADLE Agent Dec. 9, 1952 A. S. MULLGARDT ADJUSTABLE OBJECT HANDLING' CRADLE Filed Feb. 18, 1949 5 Sheets-Sheet 2 INVENTOR y ALEX S. MULITGARDT Dec. 9, 1952 A. s. MULLGARDT 2,620,930

ADJUSTABLE OBJECT HANDLING CRADLE Filed Feb. 18, 1949 s sheets-sheet s INVENTOR. ALEX S. MULLGARDT Ag e'ni A. S. MULLGARDT ADJUSTABLE OBJECT HANDLING CRADLE Dec. 9, 1952 5 Sheets-Sheet 4 Filed Feb. 18, 1949 INVENTOR. ALEX S. MULLGARDT Agent Dec. 9, 1952 A. s. MULLGARDT 2,620,930

ADJUSTABLE OBJECT HANDLING CRADLE Filed Feb. 18, 1949 5 sheets-sheet 5 YAW TRAVERSE ROLL FORWORD"o up INVENTOR. ALEX S. MULLGARDT genf Patented Dec. 9, 1952 UNITED STATES TENT SOFFICE ADJUSTABLE OBJECT HANDLING CRADLE AleXpS. Mullgardt, San Francisco, Calif., assignor to Weber Aircraft Corporation, a corporation of California Application February 18, 1949,' Serial No. '77,214

(Cl. 21d-1) move the same. Overhead cranes andmobilecranes are not always availablefor such operations and in many cases such' cranes "would not be well suited. for the Work.' The present 'invention is directed to a cradleifor receiving and supporting large heavy objects-fan'dis -constructed in such manner that it may-beelevated and 10W- ered on the forks,` o-r the like', ofa lift truckv whereby horizontal translation in one-,direction and vertical movement lis obtained bjr-operation of the truck and the cradle is further Vcoi'istructed to obtain horizontal translation in the-other direction, angular movement about a vertical-axis, angular movement about -a yhorizontal axis, and pitching or angular movementvabouta second horizontal axisl normali' tof the iirst"y horizontal axis.

It is, therefore, a general object of the 'present invention to provide a practicaLidependable and conveniently operated device'for-cradle-of the above referredrto class. The cradle` is articulated to obtainthe several motions so thatthe -objecty or device supported thereby may bereadily-and accurately positioned with-respect to its intended support or safely engaged by the cradle for-support thereby upon detachment fromitsv normalr support. The severalmotions are separably obtainable and are reversible-permitting full control and 'a wide range of adjustment or variation in the position ofthe cradlefand its load.A

Another object of the invention is toprovi'de a cradle of the charactermentionedincorporating l power means in the nature of-fiuid pressure actuated cylinder and piston-mechani'sms` for effecting the several movements of the Ysupported object, with a control system for the'sev'eral ac tuating mechanisms governed from a single sta'- tion. One workman or operatorlmaycontr'ol 'the variousI actuating mechanisms! and -thus direct the motion of the-object supported-bythe cradle and the control system is s'uch that'the movement may be accurately accomplished to bring the supported object toexactly theA desired position or to bring the` cradle into thev correct position for assuming theweightof :anobject intended to be detachedv from' its stationary 'support; Simple manipulationof'fvalvesand theac'- 2; tuation or control of-pressure' developing-crapplying means is all that is required tof'llyfcontrol actuation of the movement producing mech- Y anisms of the apparatus.`

Another Object of the-invention is `toprovideV a cradle of the character-mentionedladapted to be engaged on-theV fork of a lift truck-fand dsigned to carry the load inthe most favorable position with respect to thetruck. The `cradleis designed to be raised and lowered onfrorn the fork of the truck and is constructedto maintain" the center of gravity of the-load in as close proximity to the lift mechanism of the truck-'as posy sible. In addition the-cradle may be employed: to' Lstore or carry an engine or nacelle assembly when the cradle-is not engaged on the liftingdevice or truck.

Another object of the invention is to provide a cradle` of the class referred -to incorporating platforms for-the Workmen, constructed and arranged so that the workmen may readilyservice the object carried by the cradle; convenientlysecure the object in its permanent mounts orrelease the object When'th'e same is detached from its normal support, as the case-may be.

Other objectives and features of the invention will become apparent from the following 'detailed' description of a typical form, throughout which description reference is made to the accompanying drawings wherein:

Figure 1 is a side elevation of the cradle supported in an elevated position on a Vlift truck and showing the forward end of the lift truck;V

Figure 2 is a front end view of the elevated cradle with the side portion of the truck appearing in broken lines;

Figure 2A is an enlarged fragmentaryvertical sectional view illustrating the'pivotal mounting of one of the load supporting pads;

Figure 3 is a somewhat enlarged top or plan View Yof the cradle with certain parts broken away to appear in horizontal cross section and to betterr illustrate otherportions; V

rFigure 4 is an enlargedV fragmentary perspective view of the intermediate portion of the'cradle structure; l

5 an enlarged fragmentary'end View pitch frame; l

an'enlarged fragmentary side elevapitch rameji is an enlarged fragmentary vertical oral view taken substantially as indicated by line 'i-"iV on Figure 3 and illustrating vthe vertical bearing for Fignre 8 the pivot section of the cradle is an enlarged fragmentary vertical sectional view taken substantially as indicated by line 8-8 on Figure 3 illustrating one of the object engaging and supporting pins of the cradle; and

Figure 9 is a schematic flow diagram of the fuid pressure actuating system and control means for the movement producing mechanisms.

In the drawings, I have shown the invention embodied in a cradle intended primarily for installing, removing and servicing the engine and nacelle units of airplanes, such units usually' comprising a heavy, costly aircraft engine and the appurtenant nacelle structure. It is to be understood that this is merely one typical form and application of the invention and that the invention may be embodied in cradles for handling other devices and objects. Furthermore, while I have illustrated the cradle used in association with a more or less conventional lift truck, it will be understood that the cradle is adapted for use with other forms of mobile lift devices with or without modification.

The particular lift truck illustrated has a wheeled power-driven body I provided at one end with a generally vertical track or guide means |I for the lift mechanism. The lift mechanism of the truck includes an hydraulic ram I2 which operates through a motion multiplying arrangement to raise and lower the lifting fork I3. The truck, which is, of course, dirigible or directable, and the fork I3, which is movable vertically, are controlled by the operator seated in the truck. The guides and the lifting mechanism associated therewith, incline rearwardly and the angle of these parts is variable while the lift fork I3 usually slopes upwardly and forwardly.

The cradle of the invention includes a lower section or bed I5 to be mounted or secured on the fork I3 of the lift truck to move therewith. The bed I5 is a generally rectangular frame-like assembly of angle stock, channel stock, or the equivalent, and includes two pairs of adjacent parallel members I6 arranged with their open sides facing downwardly to receive the arms of the fork I3 and inclined in a direction to maintain the bed in a generally horizontal position when supported by the inclined forks. Removable pins or bolts may be passed through openings in the members I6 and the forks I3 to act under shear to secure the cradle to the fork. Removable straps |8 may be engaged around the assembled members and fork to resist or prevent verticalv separation of the same. The frame-like bed I5 also includes a pair of parallel generally horizontal members I9 extending between and secured to the opposite sides of the bed; see Figures 4 and 7. The members I9 are arranged with their webs in spaced opposing relation. A plate extends between and is welded, or otherwise fixed, to the webs of the members |9 at or adjacent the center of the bed I5. It will be understood that the bed I5 may be of other constructions and materials, as required, and is capable of considerable variation to adapt the cradle for use with lift trucks and the like of various designs.

The cradle further includes a pivot frame 2| arranged directly above the bed I5 and supported thereon for angular movement about a vertical axis. The pivot frame 2| is a generally rectangular assembly of rigidly connected angle stock, channel stock, or the like, including side and end members and further including two transverse horizontal members 22. The members 22 extend directly above the members I9 of the bed I5, as shown in Figure 7. A suitable bearing supports the pivot frame 2| on the plate 20 of the bed. In practice, any appropriate bearing may be employed for this purpose. In the case illustrated in Figure '7, the bearing includes races 23 and a series of balls 2d. The race and ball assembly is engaged between the plate 20 and a plate or disc 25 secured to the underside of the members 22. A boss 28 extends upwardly from the plate 20 into the race assembly and a central bolt or stud 21 extends through central vertical openings in the plates 20 and 25 and the boss 25. The pivot frame 2| further includes two diagonal brace members 28, extending from the transverse members 22 adjacent the bearing just described, to two corners of the frame. The side members of the frame 2| are generally horizontal channel parts arranged with their open sides facing outwardly and will herein be termed tracks 29. These tracks 29 serve to support a traversing frame or traveling frame 39, to be described below.

It is preferred to provide outboard supporting means or bogies to assist the above described bearing in supporting the pivot frame 2| on the bed I5. This means includes two diagonally arranged members 3| welded or otherwise fixed to one of the fork receiving channel assemblies I8 and the ends of the bed I5. These members 3| carry brackets 32 which, in turn, are provided with roller assemblies 33. Diagonal tracks Il, which also serve to brace the pivot frame assembly, are secured in the adjacent corners of the frame 2|. The rollers 33 engage or operate in the tracks 34 to assist in supporting the frame 2| on the bed I5. If desired, the rollers 33 may cooperate with the ends of the tracks 34 to limit the angular movement of the pivot frame 2| about the generally vertical axis. The structure just described is best illustrated in Figures 3 and 4.

The invention provides a power means or actuatingr means for moving the pivot frame 2| about the generally vertical axis. This preferably comprises a cylinder and piston mechanism connected between the bed I5 and the frame 2|. As best shown in Figure 4, the cylinder 35 of this mechanism is connected with one end or side member of the frame 2| by a pivotal connection 36 and the piston rod 31 of the mechanism is pivotally secured to one of the diagonal tracks 34 at a clevis pivotal connection 38. The fluid pressure lines 40, extending from the opposite ends of the cylinder 35, are controlled by the fluid pressure actuating and control system illustrated in Figure 9 and to be hereinafter described. It will be seen how the cylinder and piston mechanism 35--31 is operable to turn the pivot frame 2| in either direction to provide what I will term yawing motion of the object being handled or supported in the cradle.

The cradle further includes the traversing frame 30 mentioned above which is carried by the pivot frame 2| for generally horizontal translation. The frame 30 is a rectangular assembly having side members 4| lying adjacent and parallel with the outer sides of the above described tracks 29 of the pivot frame 2|. Each of the side members 4I carry spaced rollers, preferably incorporating anti-friction bearing means, and theserollers 42 operate in the tracks 29 to support the frame 3D for the translatory movement. Means, preferably in the form of fluid pressure actuated devices, serve to move the frame 3U in either direction. Thus, as best illustrated in Figures 3 and of the drawings, cylinf ders 43` are arrangedfin parallel"`relation` to the tracks 29 and side'iernbers 'andareanchored at 44 to an adjacent ytransverse part-ll5 of the frame 3B. The piston rods A i-'tof the vcylinder mechanism are in tu rn`-;.n ':hored orattached to the tracks 29 of the pivot frame 2|"at lugs or brackets 41. The uid pressure lines `48 and 49 from the opposite ends of the cylinders Q,'ex-V tend to the actuating and control system to be subsequently described. Calibrationsv 8 lare provided on one of the side members litocooper'ate with an adjacent part ofthe frame 2l to indicatev the setting or position of the'traversingframe 30 and similar calibrationsv may be provdedfon the other' frames to aid in the employment of; the Cradle. l

In the embodiment of the invention illustrated, the traversing frame30 is provided with means for supporting the cradle when the latter is not in use, and is further provided with a platform 52 for the workmen. suitably braced legs 55 are secured to the corner portions of the frame 3S and project downwardly therefrom to carry horizontal skids 5I. The skids 5l are` disposed in a plane below the lowermost element of the bed I5 so as to rest on the floor and support the bed as Well as the other elements f the cradle clear of the floor. The above mentioned' platform 52 is secured to the rear legs5iof` the traversing frame Si; and extends rearwardly therefrom. The platform 52 may be a rectangular structure extending across the rearend of the cradle assembly and is provided with a suitable hand rail 53. In addition to beingv secured to the legs Ell by welding or the like, the platform 52 is braced and supported by a horizontal member 55 connected with the frame 30 by spaced diagonal braces 55. rEhe platform 52 is located so that the workmen standing'thereon may` con` veniently work upon the rear portion" of the nacelle and engine assembly or'other objects en'- gaged in the cradle. It is preferred to ydetach-Y ably secure the platform 52'to the frame 3.0 so that the platform may be removed when desired to give freer access vto the nacelle and engine assembly.

v'Ihe cradle further includes what I will term a roll frame 56 supported on the traversing'frame 3Q to be movable about a substantially horizontal axis. rI'his axis of angular'movementor .roll of the frame' 5G preferably intersectsY any extension of the axis of angular movement of'fthe pivot frame 2| and is coincident with the central longitudinal axis of the traversing frame' 5i). The frame 55, which is adapted 4tor carry the nacelle and engine assembly or other object for rolling movement, includes longitudinal 'oriside members 5l of tubular stock extending between and secured to arcuate end 'elements 58 andj59.

The side members 51 may be directly welded or otherwise secured to the element 58or'to plates thereon, while the other ends of the members 5"! are rigidly secured to plates and uprights 63 on the element 5S. The elements 5,8 and 5 9 Aare in the nature of curved tracks having curved lower faces which are concentric with acommon horizontal axis spaced above'th'e roll 4frame 56. Spaced rollers 65 are vmounted the abovementioned transverse member 4 5 ofthe traversing frame 39' and the curved loweredge of the ele-e ment`58 Vbears on these rollers. "'-The' forward end member 6I of the traversing frame vIl() 'carries two spaced rollers S2 and'therollers are grooved to receive "and" cooperate with the 'curvedlower edge. Qf the ,element 59; es. Shown in Figures 1 and 2,' the arcuate track 'element 555i '.Qf 'the roll frame 56, extends downwardly into the'forward portion 'Of the' traversins frame" 39 t6, bei? Olii the grooved rollers 62. It is `believed lthatl it'will be apparent how s tructnre "juist described supports the roll frame 5 6` yfor angular movement about the abovementioned horizontal axis. The means fer actuating 0r meting the roll frame 5 6 vincludes one or more powerapplying devices. VIn the drawings Ivhaveshown a cyll inder Eil pivotally secured at one end to a'bracket 65 on a guide {l} ofthe traversing frame 3,!)` and a piston rod 65' extends from'the other end of the cylinder for pivotal connection with the arcuate track element 5 ,8 of the roll frame at 61', as shown in Figure el. 'A second cylinder dallas one end pivotally connected with a leg'A 50 ofthe traversing frame 3l) and a piston rod 89 extendsv from theother end lo f the cylinder for connectionwith the arcuate track element 5,9 at 'llf'The fluid pressure lines ll and Y'lf2 leading to the corresponding ends of the cylinders 654 and B8 are joined or manifolded, as shown in Figure 9, and extend to the fluid pressure control system to be later described, 'l

Platforms 'I3 extend along the sides of the roll frame being supported by the above described legs 53, the elements 5B, and appropriate associated bracing. Hand or safety rails 14 are provided on the platform 73. The platforms 'I3 are some distance above the rear platformy 52 and extend from the forward end ofthe cradlel to points some distance rearward of the arcuate track element 58. VThe intermediate and forward portions of the nacelle assembly, or other object carried in the cradle, are conveniently accessible to the workmen on the platforms 13.

In order to obtain a pitching movement of the supported object, that is an angular movement of the object about a generally horizontal axis normal tothe axis of movement'v of the roll frame 56, I provide what may be termed a pitch frame l5. The pitch frame lli is located above, the rear platform 52 and isadapted to engage with and support the rear portion of the load at points' spaced a considerable distance to the vrear ofthe roll frame 5G. `In the particular construction illustrated the pitch frame assembly I6 includes a rear plate 'il disposed in a substantially Vertical plane and extending lacross the'rear end of the cradle proper. This plate 'Il isl carried for vertical movement by two pairs of rearwardly divergent arms 13 having their forward ends piv` otally secured to lugs 'I9 on the rear track ele'-` ment 53 of the roll frame 5v5. The rear ends of the arms 'i8 have pivotal connections 80 with flanges 8! projecting Vfrom the yforward face of the plate l?. The axes' of the pivotal connections at 'i8 and Si) are horizontal andthe lcon-V nections are such "that the plate"- 'Il may move substantially verticallywith little or no arcuate movement.

The plate Il carries a plurality of parts for engaging with and supporting the object'vory load being handled. `These object engaging 'parts may be in the naturel of studs, sockets, bolts, clamps, adaptors or the 'like 'and any desired number of such parts or devices`may be'employed as found necessary. As best illifi'str'atedy Figures 3 and 8these parte are in the. nature of. horizontallyaligned pins. 82.,hai/ ine tubular. nor.- tions guided in sleeves voritublesn 83 welded or otherwise fixed to, the upper end; of menate 1.1. The pins 82 project inwardlyfrom thegtubes and their exposed ends are rounded or beveled to readily enter horizontal openings in the engine and nacelle assembly, or other object, to be handled in the cradle. It is desirable to provide for the retraction and advancement of the pins 82 so that they may be more readily engaged in and removed from the openings in the load. The pins 82 are held against rotary or angular movement by keys or plugs 84 secured in radial openings in the tubes 83 and cooperating with flats or grooves in the pins. Screws 85 pass into the outer ends of the tubes 83 and their thread carrying inner portions cooperate with internal threads in the tubular parts of the pins 82. Bushings 86 are screwed or otherwise fixed in the outer ends of the tubes 83 and collars 81 on the screws 85, cooperate with the bushings to hold the screws against longitudinal movement. The screws 85 extend outwardly beyond the tubes 83 and their free ends are hexagonal or otherwise formed for ready engagement by a turning tool or wrench so that the pins 82 may be projected inwardly and retracted as required by merely rotating the screws.

rlhe load or object being handled, in addition to being supported by the pins 82 of the pitch frame 16, is also supported at two horizontally spaced points on the roll frame 56. Thus the nacelle assembly, or other object being carried in the cradle, is supported at four points, namely at the two horizontally aligned pins 82 of the pitch frame 16 and the two horizontally aligned points on the roll frame 56. The rear track element 58 of the roll frame 56 carries two horizontally aligned pads 88. The pads 88 are in the nature of angular blocks having concave upper surfaces faced with an abrasion resistant material for cooperating with the nacelle assembly. It will be understood that the blocks 88 rmay be shaped and designed to support objects .of various configurations. The pads 88 bear .against substantially vertical shoulders 90 (see 4Figure 4) on the element 58 and are preferably :supported for angular or pivotal movement about generally horizontal axes so as to remain in full engagement with the load when the pitch frame 16 is moved with respect to the roll frame 56. For this purpose, pins |09 pass through horizontal openings in the pads B8 and are engaged or secured in openings in the shoulder portions of the element 58.

Means are provided for guiding the pitch frame 16 and for actuating or moving the same. These means included two generally horizontal cantilevered arms 9| rigidly secured to the ends or sides of the element 58 of the roll frame 56 and projecting rearwardly to points adjacent the plate 11 of the pitch frame 16. Vertical plates B2 are fixed to the ends of the arms 9| and appropriate braces 93 may extend downwardly and forwardly from the plates 92 to the element 5,8. rI'he plates 92 are arranged at approximately 90 to the plate 11 and the plate 11 has forwardly projecting wings or flanges 94 which lie at the outer sides of the plates 92. The plates 92 have vertical slots 95 and the flanges 94 carry bolts or pins 96 which operate in the slots 95 to guide the pitch frame 16. The means for adjusting or moving the pitch frame 16 comprises cylinders 91 secured at their upper ends to the relatively stationary plates 92 and the piston rods 98 of the cylinder mechanisms extend downwardly from the cylinders. The piston rods 98 are pivotally connected with lugs 99 on the lower edge portions of the plate 11. The fluid pressure lines and |0| leading from the corresponding ends of the cylinders 91 extend to the fluid pressure control system described below. It will be seen how actuation of the cylinder mechanisms 91 is operable to pivot or swing the pitch frame 16 about its generally horizontal axis of adjustment or movement.

The system for actuating and controlling the several cylinder and piston mechanisms of the device is diagrammatically illustrated in Figure 9 where it will be seen to include a pump P. While I have shown a manually operable pump P it will be understood that any suitable source of fluid under pressure may be employed to supply the cylinder and piston mechanisms. The high pressure line |02 of the pump P delivers the huid, preferably a liquid, to a manifold line |03. The low pressure line |04 of the pump P extends to a suitable reservoir |05 for the fluid handled in the system. In practice the reservoir |05 may be positioned adjacent the pump P and it is preferred to arrange the pump on the rear portion of the traversing frame 30 to be conveniently accessible to the workmen on the platform 52. The high pressure manifold line |93 delivers the actuating fluid under pressure to three spaced four-way valves |06, |01 and |08. The valve |06 serves to control the cylinder mechanism for moving the pivot frame 2| to obtain a yawing motion of the supported object, the valve |01 serves to control the cylinder mechanisms 43 for moving the traversing frame 30, while the valve |08 operates to control the cylinder mechanisms 64 and 68 for moving or adjusting the roll frame 56. The low pressure line |04 of the pump P has LlO a branch manifold ||0 leading to the valves |06, |01 and |08.

The abovementioned lines 40, leading from the opposite ends of the cylinder 35, extend to the valve |06 and the valve is manually operable to selectively and alternatively connect the lines 40 with the pressure supply manifold |03 and the pressure return manifold ||0. The three valves |08, |01 and |98 have suitable operating levers The lever of the valve |06 has an off position where both lines 40 are closed, a right position where pressure is delivered to one line 40 and the other line 48 is connected with the return manifold ||0 and a left position where the rst line 40 is connected with the return manifold ||0 and the second named line 40 is in communication with the pressure supply manifold |03. It will be seen that with the pump P in operation the valve |06 may be operated to pivot the frame 2| in either direction to obtain the desired yawing adjustment or motion of the cradle.

The above described pipes or lines 48 and 49 from the opposite ends of the cylinders 43 for adjusting the traversing frame 30, extend to the valve |01. The valve |01 has an off position Where both lines 48 and 49 are closed and has a forward position where the line 49 is in communication with the high pressure manifold |03 and the line 48 is in communication with the pressure return manifold ||0. The valve |01 also has an aft position where the line 48 is placed in communication with the high pressure manifold |03 and the line 49 is putin communication with the pressure return manifold I0. Thus with the pump P in operation the valve |01 may be operated or manipulated to move the traversing frame 39 either in the forward direction or the aft direction as required.

The pipes or lines 1| and 12 from the opposite ends of the cylinders 64 and 68 which move or adjust the roll frame 56, extend to and are controlled by the valve |03. The valve |38 has 'an oif position where the pipes '|I and I2 are both closed and has a position where the pipe 'H is placed in communication with the pressure supply manifold |533 and the pipe l2 is put in communication with the pressure return manifold IIB so that the roll frame 56 is adjusted to move the left side of the supported object upward. The valve m8 also has a left side down position where the pipe 'I2 is in communication with the pressure supply manifold |63 and the pipe II is in communication with the pressure return manifold I El, It will be seen that simple manipulation of the lever of the valve |83, while the pump P is in operation, serves to roll the frame 5B either to the left or to the right, as the case may be.

The control for the cylinders Sl of the pitch frame 'i6 includes a four-way valve i I 5 similar to the valves |95, lill and |08, described above, and provided with an operating lever I it. An extension or branch of the pressure supply manifold |03 extends to the valve H5 and is provided with a check valve I8 which allows the delivery of pressure fluid to the four-way valve but which prevents a reverse iiow. A branch H9 of the low pressure or pressure return manifold lid also extends to the four-way valve H5 and is equipped with a pressure relief valve IZi?. The

valve |26 is set to prevent the flow of fluid pressure from the valve l I5 to the reservoir m5 until a relatively high pressure is developed, The purpose of this valve I 2E; will be later described. The abovementioned lines |06 and Hi communicating with opposite ends of the cylinder Sl, lead to the four-way valve I5. The valve I5 has a closed or off position where the four lines H30, Eel, Ill and M9 are closed. The valve H5 also has a nose up position where the line lei] is connected with the pump pressure line i il and the line II is in communication with the low pressure or return line Ile.v When the pump P is operated with the valve I I5 in the nose up position, fluid under pressure is delivered to the lower ends of the cylinder IVI to move or swing the pitch frame i6 upwardly. On the other hand, when the valve H5 is in the nose down position and the pump P is operated, uid pressure is supplied to the upper ends of the cylinder 9'! L to swing the frame i6 downwardly. In this connection it will be observed that it is necessary to develop sufhcient pressure to overcome or open the valve l2@ when the frame i6 is to be swung downwardly. The valve |28 serves as a safety means to prevent unwanted and possibly damaging movement oi the frame lli and its load in the event the lift mechanism of the truck is perated suddenly when the valve H is in either of its open positions, In such an event the valve |26, by preventing or resisting the flow of uid through the line I ii), prevents or resists relative movement between the cylinders el and the piston rods Sil and thus effectively dampens or resists inertia or acceleration effects which might otherwise cause unwanted movement of the pitch frame and load. The check valve IIS serves a like function in preventing a reverse iiow of fluid through the line under such circumstances. The valves H8 and |20 also function to resist static unbalance of the load and pitch frame it. A'by-pass line Hill connects the supply pressure relief valve I5! which protects the overall system against the development of excess fluid pressures.

The above described valves |06, |97, les and H5, and the associated manifolds |53, H0, etc., are preferably located adjacent the pump P and may be enclosed in. a casing |2| which also contains the pump. The operating lever |22 of the pump and the levers I I and II t of the four-way valves may project from .the casing l2! to be conveniently accessible to the workmen on the platform 52. Thus there is a single station from which the various cylinder mechanisms of the device may be` controlled and operated.

It is believed that the operation of the adjustable cradle will be readily understood from the foregolng detailed description wherein the function and operation of the several principal elements thereof have been fully set forth.. As illustrated in Figures 1 and 2, the entire cradle, either with or without its load, may be lifted on the fork I3 of the truck and carried thereon.. It is desirable to secure the cradle on the fork I3 by the pins l1 and the straps IS and to secure the load in proper position in the cradle. The pads 88 serve to support one end portion cf the load while the pins 82 may be engaged in appropriate openings in the nacelle assembly, or other load, to support the opposite end portion of the same and to assist in retaining the load in the cradle. It will be observed that the concave upper edges of the elements 58 and 59 and the plate 'il' are designed to accommodate the nacelle assembly although these parts may be given other conlgurations to adapt the cradle for other loads. The workmen may stand on the platforms 52 and 'i3 to be in position to work upon or service the load or to secure or detach it from the usual supports. In detaching or mounting the load on its normal support, the cradle may be brought to any required position by appropriate operation of the truck and its lift mechanism I2 and the several movable frames 2|, 3e, E and le of the cradle. Yawing motion in either direction is obtained by operation of the pump P and valve |95, such operation resulting in turning of the frame 2| and the load about a vertical axis. Operation of the pump P and manipulation of the valve Id? causes turning movement of the frame 2| and the load about a vertical axis while operation of the pump P and valve Hi8 rolls 'the frame 5t and load about a horizontal axis. In a like manner, operation of the pump P and control of the valve I I I, causes fore and aft pitc"ing movement of the france 'I6 and the load. By'controlling and relating these several movements the cradle may be brought to the correct position to assume the weight of the nacelle or other object when the same is to be detached from its normal support and to bring the load to position for attachment to its usual mounts.

It is to be understood that while the parts or assemblies 2|, v3|), 5S and 'I6 are herein termed frames, these instrumentalities may be varied considerably in design and construction to adapt the cradle to handle loadsand objects of various kinds and the term frame is not` to be construed as limiting the invention to frame or frame-like structures.

Having described only a typicalpreferred jembodiment lof my invention I do` not wish tobe limited to the speciiic details herein. Vset forth, but wish to reserveto myself uany variations or modifications that may appearto those skilled in the art and fall'within the scope 'of the following claim-s.

Iclaim: l n l 1. vIn an object handling'c'radle a pluralityA of articulated frames including a traversing frame,

means supporting the traversing frame for translation in a generally horizontal plane, a roll frame supported on the traversing frame for angular movement about a generally horizontal axis, and a pitch frame supported on the roll frame for angular movement about a generally horizontal axis substantially normal to the first named axis, means on the roll frame and pitch frame for supporting an object, a power means for moving each of said frames, and a manually operable control system for selectively operating said power means.

2. In an object handling cradle, a roll frame, means supporting the roll frame for angular movement about a generally horizontal axis, a pitch frame extending from one end of the roll frame, means for supporting the pitch frame on the roll frame adjacent said end thereof for angular movement about a generally horizontal axis normal to the iirst named axis, object supporting means on the two frames, and means for imparting said angular movements to said frames.

3. In an object handling cradle, a roll frame, means supporting the roll frame for angular movement about a generally horizontal axis, a pitch frame extending from one end of the roll frame, means for supporting the pitch frame on the roll frame adjacent said end thereof for angular movement about a generally horizontal axis normal to the iirst named axis, horizontally aligned parts on the pitch frame adapted to have supporting engagement with an object, pivoted pads on the roll frame to assist in supporting the object, and means for selectively imparting said angular movements to said frames.

4. In an object handling cradle for use with a device having a lifting fork, the combination of a bed for attachment to the fork for elevation thereon, a plurality of articulated superimposed frames on the bed including a pivot frame supported on the bed for angular movement about a generally vertical axis, a traversing frame supported on the pivot frame for movement in a generally horizontal plane, a roll frame supported on the traversing frame for angular movement about a generally horizontal axis, a pitch frame extending from an end of the roll frame, means for mounting the pitch frame on said end for angular movement about a horizontal axis normal to the axis of movement of the roll frame, means on the roll frame for supporting an object, means on the pitch frame for assisting in supporting the object, a power means for separately moving each frame, and a manually operable control system for said power means whereby said frames may be selectively moved to adjust the position of the object.

5. An object handling cradle for use on a lift device comprising a bed for arrangement on said device to be carried and elevated thereby, a plurality of superimposed articulated frames carried by the bed including a pivot frame supported on the bed for movement about a substantially vertical axis, a traversing frame supported on the pivot frame for translation in a substantially horizontal plane, a roll frame supported on the traversing frame for angular movement about a substantially horizontal axis parallel with said plane, a pitch frame supported on one end of the roll frame for angular movement about a substantially horizontal axis normal to the axis of movement of the roll frame, means on the roll frame and the pitch frame for supporting an object, power actuated means for moving each oi said frames, and a manually operated control system for operating and controlling the power actuated means.

6. An object handling cradle for use on a lift device comprising a bed for arrangement on said device to be carried and elevated thereby, a pivot frame supported on the bed for movement about a substantially vertical axis, a traversing frame supported on the pivot frame for translation in a substantially horizontal plane, a roll frame supported on the traversing frame for angular movement about a substantially horizontal axis parallel with said plane, a pitch frame supported on one end of the roll frame for angular movement about a substantially horizontal axis normal to the axis of movement of the roll frame, means on the roll frame and pitch frame for supporting an object, cylinder and piston means for moving each of said frames, a working platform on the traversing frame, and a uid pressure system for operating and controlling the cylinder and piston means including manually operable valves accessible from said platform.

7. In an object handling cradle, a roll frame supported for angular movement about a generally horizontal axis, a pitch frame supported on an end of the roll frame for angular movement about a generally horizontal axis normal to the first named axis and to project beyond said end of the roll frame, means on said frames for supporting an object, the said means of the pitch frame being spaced outwardly from said end of the roll frame, cylinder and piston means for moving the pitch frame with respect to the roll frame, a uid pressure supply line, a iluid pressure return line, valve means for controlling the communication of said lines with the cylinder and piston means, and a pressure relief valve in the return line for preventing unwanted movement cf the pitch frame.

8. An object handling cradle for use on a lift device comprising a bed for arrangement on said device to be carried and elevated thereby, a pivot frame supported on the bed for movement about a substantially vertical axis, a traversing frame supported on the pivot frame for translation in a substantially horizontal plane, a roll frame supported on the traversing frame for angular movement about a substantially horizontal axis parallel with said plane, a pitch frame supported on one end of the roll frame for angular movement about a substantially horizontal axis normal to the axis of movement of the roll frame, means on the roll frame and pitch frame for supporting an object, cylinder and piston means for moving each of said frames, a working platform on one of the frames, a iluid pressure system for operating said cylinder and piston means including a manually operable valve for controlling the movement of each frame, and a pump for developing fluid pressure for the actuation of said cylinder and piston means, said valves and pump being carried by one of the frames in a position to be accessible from the platform.

- ALEX S. MULLGARDT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,349,633 Staley Aug. 17, 1920 2,479,623 Johnson Aug. 23, 1949

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