US 3088769 A
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May 7, 1963 Filed Oct. 18, 1961 W. F- RICHARDSON EXPANSIBLE LIFT FOR HOLLOW OBJECTS 4 Sheets-Sheet 1 e 4 l p 2 26 ,4 t I L 40 r m 4/0: 3 1
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EXPANSIBLE LIFT FOR HOLLOW OBJECTS Filed Oct. 18, 1961 4 Sheets-Sheet 3 INVENTOR. M'l/bm F fi/t/rardmfl Affornay.
May 7, 1963 w. F. RICHARDSON EXPANSIBLE LIFT FOR HOLLOW OBJECTS 4 Sheets-Sheet 4 Filed Oct. 18, 1961 INVENTOR. W/M'am F/P/b/WMM/y I Afforney.
United States Patent 3,088,769 EXPANSHBLE LIFT FOR HOLLOW OBJECTS William F. Richardson, Carthage, Mo., assignor to Flex- O-Lators, lnc., Carthage, Mo., a corporation of Missouri Filed Oct. 18, 1961, Ser. No. 145,845 9 Claims. C1. 29493) This invention relates to new and useful improvements in lifts, and has particular reference to lifts of the type consisting of an expansible head or core adapted to be suspended from a suitable hoist and lowered thereby into the interior of a hollow object to be lifted, then expanded to grip the inner walls of said object frictionally, whereby said object may be lifted and transported at will.
The principal object of the present invention is the provision of a lift of the character described the gripping action of which is entirely automatic, that is, in which the head will expand whenever it is lowered into the object to be lifted, without attention from the operator, whereby said object will be lifted when the hoist is subsequently raised. Release of the head from the object is accomplished by a simple cable pull which may be actuated at any convenient station remote from said head.
Another object is the provision, in a lift of the character described, of a hammer-blow mechanism operable to assist in both the expansion and contraction of the head whenever such assistance m'ay be necessary or desirable.
Other objects are simplicity and economy of construction, efiiciency and dependability of operation, and adaptability for use in a wide variety of applications.
With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the drawing, wherein:
FIG. 1 is a vertical sectional view of an expansible lift embodying the present invention, with the parts in the position assumed as the device is lowered into an object to be lifted, with parts left in elevation and partially broken away,
FIG. 2 is a sectional view taken on line II-II of FIG. 1,
FIG. 3 is a sectional view taken on line III-III of FIG. 1,
FIG. 4 is a sectional view taken on line IV-IV of FIG. 1, with parts omitted,
FIG. 5 is an enlarged fragmentary sectional view taken on line VV of FIG. 1, with parts omitted, and
FIG. 6 is a sectional view taken on line VIVI of FIG. 1.
Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to an object to be lifted. This object has a generally cylindrical bore or internal cavity 4 therein, and may be, for example, a heavy pipe or tube, a heavy cylindrical coil of Wire or the like, or any other object having a generally cylindrical bore 4. When in position to be lifted by the device forming the subject matter of the present invention, the object is resting on a fioor or other support with the bore 4 opening through the top thereof.
The lift includes a generally cylindrical head indicated by the numeral 6, said head being disposed with its axis in a vertical position and consisting of four quarter-cylindrical shoes 8 formed of plate steel. Each of said shoes is provided with an outer facing 10 of a non-skid, indentable material such as web belting or other fibrous material. Said facing is securely fastened to the shoe by any suitable means, such as by closely spaced rivets, not shown. Each of the shoes is provided internally with a horizontal web 12 at its lower edge, a horizontal Web 14 adjacent but spaced below its upper edge, and a central radial web 16 extending between said horizontal webs, all of said webs "ice being rigidly secured to said shoe, and said radial web being rigidly secured to said horizontal webs, as by weldmg.
Disposed axially in said head is a lift tube 18, and each of shoes 8 in connected to said lift tube by a pair of vertically spaced apart toggle links 20. Each of said links is provided at its outer end with a clevis 22 which straddles radial web 16 of the associated shoe and is fastened thereto by pivot pin 24. At its inner end, each toggle link is provided with a clevis 26 which straddles an ear 28 welded to tube 18, and is connected to said ear by pivot pin 30. All of toggle links 20 are inclined upwardly toward their outer ends, and a stop block 32 welded to the lower surface of upper web 14 of each shoe is positioned to engage the upper toggle link of that shoe to prevent sa-id link from pivoting below a horizontal position at any time. It will therefore be apparent that as lift tube 18 is raised from its lowered position as shown in FIG. 1, toggle links 20 will cause shoes 8 to be moved radially outwardly, thereby expanding the head to a larger diameter, and that when said lift tube is lowered, the head will conversely be retracted to a smaller diameter. Upward movement of tube 18 is limited by engagement of links 20 with stops 32, as previously described. Downward movement of the tube is limited by a pair of horizontal arms 34 welded at their inner ends to the upper end portion of tube 18 and extending radially outwardly therefrom in diametrically opposite directions, to a diameter greater than that of head 6. Said arms engage the upper edges of shoes 8 to arrest the downward movement of tube 18. Each arm 34 is provided at its outer end with a depending extension 36 constituting a feeler block, the function of which will be presently described. Also carried by lift tube 18 are a pair of lugs 38 of inverted U-shape. Said lugs are disposed at diametrically opposite sides of tube 18, having their lower ends Welded to the external surface of said tube, and extend upwardly therefrom.
The device also includes a vertical central shaft 40 of generally square cross-sectional contour. Said shaft includes a lower section 40a disposed for longitudinal sliding movement in lift tube 18, an upper section 40b spaced apart from but coaxial with section 40a, and a pair of parallel side plates 42 extending between and being welded to sections 40a and 40b, whereby to form a unitary structure. Said side plates overlie opposite sides of the shaft sections, and the upper ends of said side plates form upwardly facing stops 44. The space between side plates 42, and between the contiguous ends of shaft sections 40a and 40b, forms an aperture 46 through the shaft, said aperture having the same cross-sectional dimensions as sections 49a and 40b, and opening through opposite sides of the shaft.
Supported pivotally in aperture 46, on a horizontal pivot pin 48 extending between the fixed in side plates 42, are a pair of depending hooks 50. The shanks portions of said hooks are enclosed at all times within aperture 46, while the upwardly opening bight portions 52 normally extend horizontally outwardly from the shaft aperture, respectively in opposite directions. Said hooks may be pivoted inwardly, however, so that both the shanks and bights thereof are disposed entirely within aperture 46. The outward movement of each hook is limited by a stop bar 54 extending across said aperture at each open side thereof and fixed to side plates 42 by screws 56 (see FIG. 5), said bars engaging the shank portions of the hooks to prevent movement thereof out of aperture 46. Each hook 50 is provided at its upper end with an integral, outwardly extending arm 58, said arms extending oppositely to the bight 52 of the associated hook. A tension spring 60 extends between an eye 62 fixed adjacent the outer end of each arm 58, and an eye 64- fixed in the stop bar 54 at that side of the shaft. Said springs bias the two hooks outwardly against stop bars 54, so that bight portions 52 thereof extend outwardly from the shaft. A pair of flexible cables 66 are attached respectively to the outer ends of arms 54. Said cables con verge upwardly and are joined at 68 to a single flexible cable 70 which extends upwardly adjacent shaft 40. It will be readily apparent that pulling upwardly on cable 70-will pivot hooks 50 inwardly, against the pressure of springs 60, so that bight portions 52 of said hooks are retracted within aperture 46. Each hook is provided at its lower end with a cam surface 72 (FIG. 1).
Affixed to the top end of upper shaft section 40b, as by bolts 74, is an eye member 76 in which the hoist cable of a crane, or any other suitable hoisting device, may be affixed to support and manipulate the lift. Said eye member is of inverted U-shape, the legs 78 thereof overlying opposite sides of shaft section 4%. The lower ends of said legs form downwardly facing stops 80, the function of which will presently be discussed, disposed in spaced relation above shaft stops 44.
A circular hanger plate 82 is disposed for vertical sliding movement on upper shaft section 40b between stops 44 and 80, said shaft extending through a square hole 84 formed centrally in said plate, whereby rotation of said plate on said shaft is prevented. Each of the shoes 8 of head 6 is supported from hanger plate 82 by an elongated link 86. Said link is pivoted at its upper end, by pivot pin 88, between a pair of ears 98 fixed to the lower surface of plate 82, and is pivoted at its lower end, as by pivot pin 92, between a pair of cars 94 fixed to the upper surface of web 14 of each shoe.
In use, it will be seen that when the lift is hanging freely from a hoist cable or the like engaged in eye 76, the shoes 8 are supported by links 86 from hanger plate 82, said plate resting on shaft stops 44. Also, lift tube 18 at this time is held in its lowered position by gravity, arms 34 resting on the upper edges of the shoes, and the shoes are thus retracted inwardly to their minimum diameter. In this position, illustrated in FIG. 1, the bight portions 52 of hooks 50 are disposed well above the lugs 38 of tube 18.
The head 6 of the lift is then lowered into the bore 4 of the object to be lifted. As this is done, the feeler blocks 36 of arms 34 first engage the top of object 2 adjacent the bore. This arrests the downward movement of said arms, and hence also of lift tube 18. As the central shaft continues its downward movement, the shoes 6, still supported from hanger plate 82, are allowed to drop relative to tube 18, and as they drop, they are moved radially outwardly by toggle links 20, until they engage the bore 4 of object '2, whereupon their downward movement is arrested. Still further downward movement of shaft 40, which is accomplished by sliding movement of the shaft through hole 84 of the now stationary hanger plate,82, causes cam surfaces 72 of hooks 50 to engage lugs 38, and said hooks are thereby cammed inwardly, against the pressure of springs 60, until the bight portions of said hooks pass beneath the central portions of said lugs, whereupon they are snapped outwardly by said springs into vertical alignment with said lugs. Central shaft 40 is then raised, and hooks 50 engage lugs 38 to support lift tube 18 directly from the shaft. Lifting tube 18, while shoes 8 are free to move downwardly relative to said tube because of the spacing of plate 82 above shaft stops 44, causes toggles 20 to force said shoes outwardly with tremendous force, said force of course being dependent on the weight of object 2. With a nonskid facing, such as the web belting shown at 10, object 2 may be lifted and transported with no danger whatever thatit will slip off of the head.
ItrWill be noted that the initial clearance between hanger plate 82 and stops 80, when the device is in its normal position as shown in FIG. 1, is less than the. totaldowrrward movement of shaft 40,which is required to lower hooks 50 into engagement with lugs 38. This provides that in the event the shoes 8 should fail to expand properly by action of gravity as described above, and such failure could be caused by sticking of toggle links 20, or by the fact that head 6 might be pressed tightly against one side of bore 4, then stops of the shaft will strike a downward hammer-blow on the upper surface of plate 82, the force of this blow being delivered through links 86 to the shoes to cause expansion thereof. Shaft 40 may be alternately raised and lowered several times to repeat this hammer blow action, if necessary.
To release thev object 2, said object is first lowered onto a floor or other support, and shaft 40 is still further lowered until bights 52 of hooks 50 are out of engagement with lugs 38. Cable 70 is then pulled upwardly, being operable from any station convenient to the op erator and remote from the lift. This retracts the bights 52 of the hooks within the aperture 46 of the shaft, so that when shaft 40 is again elevated, said bights will pass between the lugs without engaging them, leaving arms 34, and hence lift tube 18, supported on the upper end of object 2. Continued upward movement of shaft 40 brings shaft stops 44 into engagement with hanger plate 82 to raise said plate, and elevation of said plate acts through links 86 to raise shoes 8 relative to tube 18, whereupon said shoes are retracted inwardly by toggle links 20. If shoes 8 are difiicult to dislodge from the Walls of bore 4, as might occur for example if links 20 closely approach the horizontal or if projections of object 2 have become embedded in the relatively soft shoe facings 10, shaft 40 may be alternately raised and lowered several times so that stops 44 deliver a series of upward hammer blows to the lower surfaceof hanger plate 82, thereby dislodging the shoes from the bore walls. This effect is further improved by the fact that links 86 are inclined inwardly toward their upper ends. This provides that the lifting force exerted 'on the shoes by links 86 will have a radially inward component tending to retract the shoes inwardly even independently of the action of toggle links 20.
While I have shown and described a specific embodiment of my invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention as defined by the scope of the appended claims. For example, means other than toggles 20, such as hydraulic rams, could be utilized for expanding the shoes, with movement of member 18 supplying fluid to the rams. Means other than arms 34 could be utilized for limiting downward movement of member 18. Feeler blocks 36 could be dispensed with, if for example, member 18 were extended downwardly sufficiently to engage the floor beneath object 2. Latching means other than hooks SO 'and lugs 38 could be utilized. For all purposes except the hammer blow effect of stops 80, flexible cables could be substituted for support links 86, and plate 82 would not then necessarily be slidable on shaft 40. Means other than springs 60 and cable 70, such as electrical means, could be utilized for operating books 50. These as well as many other changes are considered to be within the scope of the following claims.
What I claim as new anddesire to protect by Letters Patent is:
1. An expansible lift for hollow objects having internal bores or recesses opening upwardly, said lift comprising a plurality of arcuately curved, angularly related shoes forming in conjunction a generally cylindrical head having a vertical axis, a lift member disposed for vertical movement centrally in said head, toggle links pivotally connected at their inner ends to said lift member and at their outer ends to each of said shoes, said toggle links being upwardly inclined toward said shoes whereby upward movement of said lift member will expand said shoes and downward movement of said lift members will contract said shoes, a feeler member affixed to said lift member and normally resting on the tops of said shoes whereby to limit downward movement of said lift member relative to said head, said feeler member extending outwardly from said head whereby to engage the top of an object to be lifted as said head is lowered into the bore thereof, and thereby arrest downward movement of said lift member, a vertical shaft disposed centrally of said head for vertical movement relative thereto and extending thereabove, means for attaching the upper end of said shaft to a hoist, a hanger member carried by the upper portion of said shaft, support members extending between said hanger members and each of said shoes, said support members permitting radial movement of said shoes and downward movement of said shaft relative to said shoes, a lug afiixed to said lift member, an upwardly opening hook carried by said shaft in vertical alignment with said lug, said hook being spaced above said lug when said shoes are suspended by said support members, said hook being horizontally movable with respect to said shaft whereby to pass beneath and engage said lug, and means for moving said hook horizontally.
2. An expansible lift as recited in claim 1 wherein each of said shoes is provided with a facing of non-skid material.
3. An expansible lift as recited in claim 1 wherein said hook moving means constitutes resilient means biasing said hook horizontally relative to said shaft to a position in vertical alignment with said lug, said hook being provided at its lower end with a cam surface operable to engage said lug as said shaft is lowered relative to said lift member whereby to move said hook horizontally against said resilient means to pass beneath and engage said lug, and manual means for moving said hook against said resilient means.
4. An expansible lift as recited in claim 1 wherein said lift member constitutes a hollow vertical tube, and wherein the lower portion of said central shaft is vertically slidable in said tube.
5. An expansible lift as recited in claim 1 wherein said lift member constitutes a hollow vertical tube, and wherein the lower portion of said central shaft is vertically slidable in said tube, wherein are included a pair of said lugs of inverted U-shape disposed respectively at opposite sides of said shaft, and wherein are included a pair of said hooks carried in an aperture of said shaft and normally extending outwardly from said recess respectively in opposite directions to engage said lugs.
6. An expansible lift as recited in claim 1 wherein said lift member constitutes a hollow vertical tube, and wherein the lower portion of said central shaft is vertically slidable in said tube, wherein are included a pair of said lugs of inverted U-shape disposed respectively at opposite sides of said shaft, and wherein are included a pair of said hooks carried in an aperture of said shaft and normally extending outwardly from said recess respectively in opposite directions to engage said lugs, and wherein said hook moving means constitutes resilient means biasing said hooks to their normal extended position and manual means for retracting said hooks within said recess, each of said hooks being provided with a cam surface operable to engage the associated lug as said shaft is lowered relative to said lift member, whereby said hooks are urged into said shaft aperture against the pressure of said resilient means.
7. An expansible lift as recited in claim 1 wherein said support members are inclined upwardly and inwardly to said hanger member, whereby upward movement of said shaft after said hook is disengaged from said lug will cause said support members to exert an inward force on said shoes.
8. An expansible lift as recited in claim 1 wherein said hanger member is vertically slidable on said central shaft, and with the addition of stops on said shaft limiting downward movement of said hanger member thereon and wherein said support members constitute rigid links each pivoted at one end to said hanger member and at its opposite end to one of said shoes.
9. An expansible lift as recited in claim 1 wherein said hanger member is vertically slidable on said central shaft, and with the addition of stops on said shaft limiting movement of said hanger member thereon, the amount of movement of said hanger member on said shaft permitted by said stops being less than the downward movement of said shaft relative to said lift member required to effect engagement of said hook with said lug, and wherein said support members constitute rigid links each pivoted at its respective ends to said hanger member and one of said shoes.
References Cited in the file of this patent UNITED STATES PATENTS 1,734,360 Bittman Nov. 5, 1929