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Publication numberUS2265892 A
Publication typeGrant
Publication dateDec 9, 1941
Filing dateApr 8, 1941
Priority dateApr 8, 1941
Publication numberUS 2265892 A, US 2265892A, US-A-2265892, US2265892 A, US2265892A
InventorsErich Bloch
Original AssigneeErich Bloch
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Jack
US 2265892 A
Abstract  available in
Images(3)
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Claims  available in
Description  (OCR text may contain errors)

DCC- 9, 1941- E. BLOCH 2,265,892

JACK Filed April 84, 1941 3 Sheets-Sheet 1 INVENTOR E/z c EZUC ATTORNEYS v Dec.' 9, 19 l41 A E, BLQCH 2,265,892

JACK Filed April 8, 1941 5 Sheets-Sheet 2 s 4 i A /27 fz; 0 f 30 l ,J4/34 l f4 J5 'wlf" z:

F Il will INVENTOR Efzc Blo ATTORNEYS E. aLoCH JAcK Filed April 8, 1941 Zewak, PW

.yf/f

Patented Dec. 9, 1941 uNlTED OFFICE y :Aok

f Erich Bloch, New York, N. Y. Y Application April s, 1941, serial No. 387,441 '1c 1254-15 inafter described.

Conventional lifting jacks have a limited range .of Alifting height. If adapted to lift low bodies the conventional jack cannot be used to lift bodies disposed a substantial distance above the ground. 1f the conventional jack is adapted to lift bodies disposed high off the ground, it cannot be placed under low bodies, and is cumbersome and too heavy to be moved with ease. Y

There have been suggested heretofore jacks capable of lifting bodies to a considerable height,

ground. However, certainfeatures of Y such jacks being provided with an vextensible member composed of successive sections each of which when raised upwardly by a suitable mechanism will lift preceding sections of the extensible member. 'Lifting jacks of this character generally have been constructed with extensible lifting members composed of solid sections either unconnected or articulated so that the propelling mechanism moves successive solid sections into lifting position. Both the unconnected and the articulated lsolid sections known heretofore have been subject to the disadvantage that they were not adapted to lift objects located close to the ground or that when used to lift objects located a substantial distance above the ground the extensible lifting member composed of the solid sections have a tendency to buckle and allow the lifted object to fall. Other lifting jacks have been known in which the extensible lifting member is composed of a plurality of solid cylindrical shaft portions, but these cylindrical shaft portions are also subject to a tendency to buckle. The solid sections in lifting jacks known heretofore require a large amount of space for storage of the sections of the extensible lifting member. Thus,

lifting jacks adapted to lift objects disposed a substantial distance above the ground have required dso much space for storageof the lifting elements as to render such jacks impractical because of their size. Y

I have' devised a novel lifting jack having an extensible lifting member` composed of a plurality of sections which are light yet strong and resist buckling and'which may be stored ina of space. In accordance with my invention I' provide a frame and a plurality of groups of mating sections movably mounted within the frame, each group when mated in juxtaposition forming a relatively short shaft portion adapted to abut at its ends another similar shaft portion formed by another group of mated sections. The shaft -portions are preferably hollow and means are provided for storing unmated sections in nesting relationship within the fr'am'e. Means are also provided .for advancingthe mating sections of successive groups into juxtaposition in abutment with the mated sections of the preceding group. Corresponding sections of each group of mating sections are articulated, as byv coupling means, in such manner as, to permit storage thereof in nesting relationship to one another, the unmated corresponding sections preferably being stored within the frame in. a position substantially parallel to the axis of the shaft portion formed by mated sections. Supporting means is mounted on the frame for maintaining the axis of the shaft in fixed position with respect to the frame. Projecting elements secured t'o each of the mating sections engage guide tracks mounted on the frame .adapted, in cooperation with the coupling means, to guide matingsectlons of successive groups from thestorage space into juxtaposition. Driving means is provided engaging mated sections for moving each group of mated sections along the axisof the shaft formed by the mated sections. These and other features of the apparatus of my invention will beseen in the drawings in which:

Fig. 1 is a side view of the lifting jack, partly in section;

Fig. 2 is a plan view taken along line 2-2 in Fig. 1; Fig. 3 is a cross-sectional detailed view of the coupling means between successive corresponding mating sections when successive mated sections are. in abutment as shown at Ain Fig. 1 and taken along line 3-3 in Fig. 4;

Fig. 4 is a view of the coupling means shown in Fig. 3 taken along line 4 4 in Fig. 3;

Fig.l 5 is a plan view of the coupling means shown in Fig. 3 taken along line 5-5 in Fig. 4; Fig. 6 is a cross-sectional view of the coupling means when successive corresponding mating sectionsare in the position indicated at B in Fig. 1;

Fig. '7 is a cross-sectional View of another modification of the lifting jack of this invention;

Fig. 8 shows mating sections particularly adapted for use as an extensible conduit for fluids; and i Figs. 9, 10, -11 and 12 show the cross-sectional `|4 until the projections 25 of tance above the top thereof is a cylindrical supporting member I4. The supporting member I4 is provided adjacent its upper portion with two or moresets of bearings such, for example, as

the bearing supports I5 carrying the ball bearing I6. Each set of bearings may comprise, for example. six bearings disposed radially about, the cylindrical supporting member I4 on the outer surface thereof. The two sets of bearings I6 shown in Fig. 1 are disposed longitudinally of the cylindrical supporting member I4 a rela` tively short distance apart on the upper outer surface thereof.

The uppermost section of the extensible lifting member'comprises a cylindrical portion I1 of slightly greater diameter than the diameter of the cylindrical supporting member I4 and adapted to rest, in its lowermost position, about the bearings I6 on the upper portion of the cylindrical supporting member I4. The cylindrical portion I1 is provided at its top end with a cap I8 provided with a recessed seat 20. A projecting member 2| is mounted on a plate 22 adapted to rotate within the recessed seat 20, friction being minimized by ball bearings 23. The projecting member 2| is adapted to engage an appropriate saddle or recess in the body of the object to be raised by the lifting jack.

The mating sections 24 shown in Figs. 1 and 2 comprise vertical half-sections of a relatively short cylinder such that when mated in juxtaposition the mating sections form a relatively short hollow cylindrical shaft portion. 'I'he general shape of these mating sections 24 is shown in Fig. 8. The mating sections 24 are stored in nesting relationship within the frame I3, the stored nested sections in accordance with the now preferred embodiment of my invention assuming a position substantially parallel to the axis of the shaft portion formed by mated sections. Corresponding mating sections are stored together within the frame on each side of the cylindrical supporting member I4.

Each of the matin'g sections is provided adjacent its open side with projections 25 extending outwardly from the mating section substantially at right angles to the axis thereof. The projections 25, which may with advantage be of the roller type, engage the guide tracks 26 on each side of the frame, the guide tracks 26 and the projections 25 being so positioned as to hold the stored mating sections suspended above the bottom of the frame I3. 'I'he guide tracks 26 extend longitudinally of the storage space Within the frame I3 toward the cylindrical supporting member I4 in a direction perpendicular to the axis of the supporting member I4. The guide tracks 26 curve upwardly in the vicinity of the cylindrical supporting member I4 and converge along each side of the frame I3 substantially parallel with the axis of the cylindrical supporting member I4.v Thus, mating sections moved toward the cylindrical supporting member I4, being guided by the projections 25 engaging the guide tracks 26, are guided inwardly and upwardly as they approach the cylindrical supporting member each group of mating sections 24 move into the point of`convergence of the guide tracks 26. At this point, the

the slotted channel tions may be used in mossos matingr sections of each group are brought into juxtaposition and form a relatively short hollow shaft portion surrounding the cylindricalsupporting member I4. The mated sections thus brought into juxtaposition engage', at their interior surface, the bearings I6. Thus, the cylindrical supporting member I4 supports the mated sections;24 for maintaining the axis of the shaft, composed of one or more abutting shaft portions, in ilxed position with respect to the frame I3. The bearings I6 permit vertical and supported movement of the mated sections along the cylindrical supporting member I4 with a minimum of friction.

Each of the mating sections 24 is provided on its outer surface diametrically opposite its open face` with a slotted channel 21 extending longitudinally thereof. The slotted channel 21 is disposed immediately adjacent the outer surface of each mating section 24 at thelower end thereof. The slotted channel 21 projects outwardly and upwardly towards the section 24, the slotted channel 21 adjacent the upper end of each mating section being separated from the exterior surface of the mating section and forming the compartment 28. The upper end of each slotted channel 21 projects upwardly beyond the upper end of the matingsection 24 to which it is attached in a direction substantially parallel to the axis thereof.

Successive corresponding mating sections are interconnected or articulated byfa connecting link such as the coupling means 30. This couplingmeansl may with advantage, be of the type described in U. S. Patent No. 1,984,092. Such a coupling means comprises two L-shaped arms 3| and 32. Arms 3| and 32 common axis 33 in the bend of each L. The end of the long leg of L-shaped arm 3| is slidably mounted in a groove 34 in the sliding member 35. The sliding member 35 is positioned within 21 and is provided with rounded sides to permit pivotal as well as sliding movement of the sliding member 35 within the slotted channel 21. The sliding member 35 is held within the slotted channel 21 by means of the shoulder 36 in the lower end of the channel. The end of the short leg of the L-shaped arm 3| is pivotally mounted as at 31 in the pivoted member 38. 'I'he pivoted member 38 is mounted for rotation about the fixed axis 39 supported by the base member 40, the outer surface oi' the pivoted member 38 being curved as at 4| to permit pivoting of the member 38 about the axis 39 within the chamber 28. The base member 40 is mounted on the upper exterior surface of the mating section 24. The end of the long leg of the L-shaped arm 32 is slidably mounted in the groove 42 inthe pivoted member 38. The end of the short leg of the L-shaped arm 32 is pivotally mounted as at 43 in the sliding member 35. Ther coupling means advantageously comprises, as shown in the drawings, a pair of 'invention 'is not limited thereto. Thus, other coupling means of similar or equivalent funclieu of the vspecific coupling means described hereinabove `in accordance with my invention.

'Ihe function of the above-described coupling means is such as to permit horizontal displaceupper end of each mating are pivoted on a succeeding corresponding mating sections 24 when the succeeding mating sections are'brought into vertical alignment, as shown. in Fig. 3 (the position shown at A in Fig. 1). This type of o coupling means, together with the 'feature of the I coupling means being slidably mounted in the slotted channel 21, permits storing the corresponding sections of each group of mating Asections in nested relationship within the framefl3. Thus, the corresponding mating sections 24 stored in nesting relationship within the frame I3 are articulated by the coupling means comprising the pivoted member 38 pivotally mounted within the chamber 28 and the sliding member 35 disposed 'within the upper portion of the slotted channel 21. As each mating section is advanced toward'the cylindrical supporting member I4 along guide tracks 26 the mating section 24 is raised vertically as its projections 25 move along the upwardly curved portion of the guide track 26, and the sliding member 35 of the coupling means slides downwardly along the slottedA channel 21 of the mating section 24 being raised. When the mating section 24 is thus brought into juxtaposition, by means of guide tracks 26, with its complementary mating section, the action of the coupling means is such as to draw the mating sections 24 of this group upwardly into abutment with the preceding group of mated sections asV shown at A in Fig. 1. The reverse of this procedure takes place and the mating sections are returned to their storage space as -the extensible lifting member is lowered by reversal of the driving mechanism.

` The upper ends of the slotted channels 21 of the mated sectionsv of each group overlap the bottom portion of the slotted channel 21 of the preceding group of mated sections thus holding together the mated sections of the preceding group. This construction contributes -to the nonbuckling characteristic of the extensible lifting member of my invention. At all times the lowermost group of mated sections will be held in juxtaposition by the terminating, vertically disposed, converging ends of the guide tracks 26,7and the axis of the shaft composed of successive abutting groups of mated sections is held in xed position with respect to the frame I3 by means of the support given to the lowermostrmated group by the cylindrical supporting member I4.

Each mating section 24 is provided on each side with a tooth rack 44 extending substantially the full length of the mating section as shown in Fig. 8. Mated sections supported by the cylindrical supporting member I4 are raised, as shown in Fig. 2, by means of pinions 44 engaging the tooth racks 43.` The pinions 45 are driven, for example, by means of additional pinions 46 mounted on shafts 41 driven by a common drivechain 48, one of these shafts 41 being driven by a power chain 49. It must be understood, however, that other equivalent driving mechanism may be used Within the scope of my invention. Thus, in the specific driving mechanism shown in Fig. 2, by driving the chain 45 the pinions 45 which engage the tooth racks 44 raise the mated sections 24 upwardly around the cylindrical supporting member I4. As the mated sections are being raised succeeding ma-ting sections are drawn upwardly from the storage space Within the frame I3 into abutment with the preceding mated sections.

The modified lifting jack shown in Fig. 7 differs from that shown in Figs. 1 and 2 inthe lifting mechanism. In the apparatus shown in Fig. '7,- a

, supported on frame I3 by means of ball bearings,

or the like, 55. The cylinder 5I is rotated by rotary movement of the bevel gear 56 engaging the bevel gear 54. The upper outer surface of the cylinder 5I is provided with a helical tooth 51 which may with advantage comprise one complete helical revolution about the' cylinder 5I. The ends of this tooth are preferably tapered as at 58. The inner surface of the mating sections 24 is provided with a helical groove 60 having the same pitch as the helical tooth 51. By selecting a pitch of the groove 60 which is either equal to or a fraction of the length of the mat--w ing sections 24, each mating section may be provided with the same groove so that such mating sections are standardized and therefore interchangeable.v Rotary moy/ement of the cylinder 5I in the direction of the arrow raises the mated sections to afford the desired lifting action. The mating sections 24 raised vertically and brought into juxtaposition by the projections 25 moving along the upwardly converging guide tracks 26 form a cylinder having internal grooves 60 which are engaged by the tooth 51. The tapered'ends of the tooth 51 accommodate slight Variations from a perfectly continuous helical groove 60 occasioned, for example, by a slight gap between the ends of the already mated sections and the immediately succeeding matingsections being and 2, are modified by being provided with a cutout portion 6I adjacent the upper inner surface thereof and with a cut-away portion 62 on the lower exterior surface thereof. This modification permits operative and fluid-tight engagement between the adjoining ends of succeeding mated sections and is particularly advantageous when the extensible member of my apparatus is used for conveying fluids. A fluid-tight joint is further provided between mated sections in juxtaposition by engagement between the tongues B3 and the grooves 64 provided in the longitudinal edges of the mating sections along theiropen faces.

Although my invention has been described hereinabove with respect to the use of mating half-sections which form the hollow shaft portions of the extensible lifting member, other types of shaft portions may be used with advantage. For example, the mating sections when mated may have a cross-sectional configuration which is pear-shaped, as shown in Fig. 9, or an elliptical shape such as is shown in Fig. 10, a rectangular shape as shown lin Fig. 11, or a polygonal shape as shown in Fig. 12. The shaft portions used in accordance with my invention may be half-sections of the desired shape as described herein'- above, or they may comprise a plurality of mating sections such that three or more mating sections together form a single shaft portion.

It Will be seen, therefore, that the apparatus of my invention presents a lifting jack which is capable of lifting bodies located close to the -ground or bodies disposed high above the ground. The lifting jack of my invention is further characterized by a large lifting range, it being equally effective when lifting low bodies as when lifting high bodies. Moreover, the extensible lifting member is strong, durable and light yet resists the tendency for the sections of the extensible lifting member to buckle. The lifting jack ls compact, and the nesting relationship between -stored mating sections which form the extensible lifting member permits the inclusion of a large number of these mating sections Within the frame of the jack. Inasmuch 'as-the groups of mating sections may form hollow shaft portions, which shaft portions may be such as to be fluid-tight,

the extensible shaft in accordance with the invention may be utilized not only as a lifting member but also, with particular advantage, as an extensible fluid-conducting member.

Thus, although the apparatus of my invention has been described with particular reference to lifting jacks wherein the invention presents outstanding advantages of particular importance in f broadly to apparatus wherein an extensible tube or shaft is desired. y

I claim:

1. vIn apparatus of the character described, a frame, a plurality of-,groups of mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted to abut at its ends another similar shaft portion formed by another group of mated sections, means for storing unmated sections in nesting relationship within said frame, and means for advancing said sections of successive groups into juxtaposition in abutment with the mated sections of the preceding group. I

2. In apparatus 'of' the character described, a

frame, a plurality of groups of mating sections 'movably mounted within said frame, each group when mated in juxtaposition forming a relatively short shaft portionadaptedfto abut at its ends another similar shaft portion formed \by another Agroup of mated sections, meansffor storing the sections within said frame in a position substantially parallel to the axis of the shaft portion formed by mated sections, and means for advancing said sections of successive groups into juxtaposition in abutment Awith the mated sections of the preceding group.'

3. In apparatus of the character described, a frame, a plurality of groups of` mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion'adapted to abut at its abut similar shaft portions formed by similar groups of mated sections, coupling means interconnecting successive corresponding sections of said groups, means for storing corresponding sections of said groups in nesting relationship within said frame, supporting means mounted on the frame for maintaining the axis of the shaft in fixed position with respect to the frame, and means for advancing unmated sections of successive groups into juxtaposition in abutment with the mated sections of the preceding group.

5. A lifting jack which comprises a frame, a plurality of groups of mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively'short hollow shaft portion adapted at its ends to abut similar shaft-portions formed by similar groups of mated sections, means for storing correspondingse'ctions of said groups in nesting relationship within said frame, means for guiding said -mating sections from the storage means into juxtaposition in abutment with the mated sections of the preceding group, supporting means mounted on the'frame for maintaining the axis of the shaft in fixed position with respect to the frame, and driving means engaging said mated sections for moving the mated sections along the axis of the shaft formed by said sections.

6./In apparatus of the character described, a frame, a plurality of groups of mating sections movably mounted in said frame, each group when mated i'n juxtaposition forming a relatively short hollow shaft portion adapted at its ends to abut similar` shaft portions formed by similar groups of mated sections, corresponding sections of said groups being articulated in such manner as to ends similar shaft portions formed by similar Y groups of mated sections, means for storing said sections in nesting relationship within said frame in a position substantially parallel to the axis of the shaft portion formed by mated sections, and means for advancing unmated sections of successive groups into juxtaposition in abutment with the mated sections of the preceding group.

'4. In apparatus of the character described, a frame, a plurality of groups of mating sections movably mounted Within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted at its ends to permit storage thereof in nesting relationship to one another, means for guiding said sections from the storage means into juxtaposition, and means for moving said sections into juxtaposition in abutment -with the mated sections of the precedmg group.

7. Inl apparatus of the character described, a frame, a plurality of groups of mating sections movably mounted .within said frame, each group when mated in juxtaposition forming a relatively short hollow, shaft portion, said sections being provided at the ends thereof with means for operatively engaging the ends of adjoining corresponding sections, supporting means mounted substantially centrally within the frame for maintaining the axis of the shaft in iixed position with respect to the frame, means for storing corresponding sections of said groups in nesting relationship separatelyl within the frame on opposite sides of said supporting means, and means for advancing said sections of successive groups from the storage means into juxtaposition in abutment with the mated sections of the preceding group. A

8. A lifting jack which comprises a frame, a plurality of groups of mating sections movably mounted in said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted at its ends to abut similar sh'aft portions formed by similar groups of mated sections, coupling means interconnecting successive corresponding sections of said groups, means for storing said sections within the frame innesting relationship, guide tracks mounted on the frame adapted in cooperation with said coupling means to guide mating sections of said groups from the storage means into juxtaposition, projecting elements secured to said mating sections and engaging the guide tracks,

supporting means mounted on the frame for maintaining the axis of the shaft in :dxed position with respect to the frame, and driving means engaging the mated sections for moving the sec-v group of mated sections, a rack attached to the surface of each section and disposed along the length thereof, a pinion operatively engaging the portions formed by similar groups of mated secy corresponding sections of said groups, the coupling means being adapted to draw the corresponding mating section of one group into abutment with the preceding corresponding section as said mating section is brought into juxtaposition with the other mating section of its group, means for storing the ,mating sections within the frame in a position substantially parallel to the axis of the shaft portion formed by mated sections, guide tracks mounted on the frame adapted in cooperation with said coupling means to guide mating sections of said groups from the storage means into juxtaposition, projecting elements secured to said mating sections and engaging the guide tracks, supporting means mounted on the frame for maintaining the axis of the shaft in xed position with respect to the frame, and driving means engaging the4 mated sections for moving the sections of said groups alongthe axis of the shaft formed by said mated sections.

10. A lifting jack which comprises a frame, a plurality of groups of mating sections, each group comprising a pair of vertical half-sections of.a

relatively short cylinder movably mounted within the frame, each pair of half-sections when mated in juxtaposition forming a relatively short hollow shaft portion adapted to abut at its ends another similar shaft portion formed by mated j half-sections of similar groups, a slotted chanracks of said sections when mated in juxtaposition, means for storing unmated corresponding sections f said groups in nesting relationship,

and means for advancing said sections successively into juxtaposition.

mounted within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted to abut at its ends another similar shaft portion for'med by another group of mated sections, said mating sections being provided with helical elements, driving means rotatable about the axis of the shaft portion formed'by a group of said mating sections when brought into juxtaposition and having helical elements adapted to engage the helical elements on said mating sections, means for storing unmated corresponding sections of said groups in nesting relationship, and means for advancing said sections successively into juxtaposition.

14. A lifting jack which comprises a frame, a plurality of groups of mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion formed by another group of mated sections, said mating sections being provided-on 'the interior surface thereof with a helical groove, a rotatable shaft mounted for rotation within the hollow shaft portion formed by a nel extending along the length of the exterior surface of each mating section; a connecting link slidably mounted at one end thereof in the slotted channel and connected at the other end thereof with one end ofthe next succeeding vcorresponding section, whereby movement ofone section is imparted t o the next succeeding corresponding section and whereby the corresponding sections may be stored in nesting relationship, means for storing corresponding unmated sections in nesting relationship within said frame, and means for advancing said sections of successive groups into juxtaposition in abutment with the mated sections of the preceding group.

11.` In combination with successive corresponding sections of a plurality of groups of mating sections interconnected so as to impart the motion of one section to the next succeeding corresponding section, each group of sections when mated in juxtaposition forming a relatively short shaft portion, a slotted channel extending along the length of each mating section and a connecting link slidably mounted at one end thereof in the slotted channel and connected at the other end thereof with one end of the next succeeding corresponding mating section.

12. A lifting jack which comprises a frame, a plurality of groups of mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted to abut at its ends another similar shaft portion formed by another juxtaposition, said shaft being provided with a helical tooth adapted to engage the helical groove on the interior vsurface'of said mating sections when brought into juxtaposition, means for storing unmated corresponding sections of said groups in nesting relationship, and means for advancing said sections successively into juxtaposition. y

l5. A lifting jack which comprises a frame, a plurality of groups of mating sections movably mounted within said frame, each group when mated in juxtaposition forming a relatively short hollowv shaft portion, a slotted channel extending along the length ofthe exterior surface of each mating section, a connecting link slidably mounted at one end thereof in the slotted channel and connected at the other end thereof with one end of the next succeeding corresponding. matingl section, whereby movement of one section is imparted to the next succeeding corresponding section and whereby the corresponding sections may be stored in nesting relationship, means for stormated sections for moving the sections of said groups along the axis of the shaft formed by said mated sections.

16. In apparatus of the character described, a frame, a plurality of groups of mating sections movably mounted in said frame, each group when mated in juxtaposition forming a relatively short hollow shaft portion adapted at its ends to abut similar shaft portions formed by similar groups of mated sections, means for storing the corresponding sections within separate portions of the frame in nesting relationship, supporting means mounted within the frame substantially intermediate the separate storing meansy for'said lcorresponding sections for maintaining the axis of the shaft in xed position ylith respect to the frame,A coupling means interconnecting successive correspondingsections ot said groups, guide tracks mount-ed or the trame extending from the storage means inwardly toward the supporting means in a direction perpendicular to theaxis of theshaft portions formed by said mated sec-

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4875660 *Feb 6, 1989Oct 24, 1989Pierre GagnonPush actuator
US6547216Apr 12, 2000Apr 15, 2003Gestion Laforest Inc.Multiple balls supported push actuator
US6928774 *Aug 4, 2000Aug 16, 2005Blowup Media GmbhEnveloping body
US7213796Jul 1, 2004May 8, 2007Gestion Laforest Inc.Linear actuator with releasably interlocking bands
US20060005651 *Jul 1, 2004Jan 12, 2006Laforest PierreLinear actuator with releasably interlocking bands
CN102115016A *Dec 1, 2010Jul 6, 2011郑仙丽Single liftable compound pipe
Classifications
U.S. Classification254/1, 254/98, 52/123.1, 254/95
International ClassificationB66F11/00
Cooperative ClassificationB66F11/00
European ClassificationB66F11/00