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Publication numberUS1073294 A
Publication typeGrant
Publication dateSep 16, 1913
Filing dateApr 6, 1911
Priority dateApr 6, 1911
Publication numberUS 1073294 A, US 1073294A, US-A-1073294, US1073294 A, US1073294A
InventorsAlexander Siewert
Original AssigneeAlexander Siewert
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Extension and retraction device.
US 1073294 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)





Fig. 2.

lll/[11111 A Laxman smwnar, or BERLIN, GERMANY.,


To all whom t may concern:

Be it known that I, ALEXANDER SIEWERT,

` a subject of the King of Prussia, and residingatBernburgerstrasse 24-25 Berlin, Germany, have invented certain new and useful Improvements in Extension and Retraction Devices, of which the 'following is a yspecification.

This inventionrelates to a' mechanism for the extension of telescoping masts and 'other extensible and retractable supports and lifting apparatuses.

It consists in causing the separate telescoping parts provided with internal threading to be extended consecutively upona spindle placed in the interior of themechanism.

Apparatuses are already known in which platforms and the like are raised by turning spindles.A It'has` nevertheless not previously been possible to construct in `this manner masts and the like the length of which4 considerably exceeds twice the lengthv of the lifting spindle.- By the present invention, masts andthe like can be extended' by aid of a spindle the length of which need only `be a fraction of the height of the extended mechanism.

The invention is illustrated in the drawing in two figures, of which-'- Figure 1 is a longitudinal elevation, and Fig. 2 a section on the line A-.A of Fig-1.

The telescopic parts b, Z2 and b are arranged in a casing c and their extension is effected by means of a spindle a revolubly supported `in the foot'of the casing, which spindle has a rather greater length than that of eachseparate tube.`- The lower part of the spindle is without threading. The tubes :are provided at their lower end with internal threading, which Vwith the exception of the'innermost tube b is out of engagement with the spindle threading when the mast is retracted. On turning'the spindle a by .means of the threading e, first the innermost tube b is raised, until it strikes with an -annular projection f against the projection g'of the tube bsurrounding it. It then Carries this tube with it so that the matrix thereof engages with the spindle a and then leaves the spindle inasmuch as it has been bolted to the aforesaid tube Z2 by means of an automatic locking device. For this purpose, holes h are provided in V,the tubes, which coincide with one another when the l',Siieiileation ofy Letters Patent.

.application ma april a. 1'911.

Vlatam-.toa sept. 16. 1913.

Serial No. 618,361.

-lower projection f of the then inner tube of the tube surrounding it. On the tubesis placed in slot z' a pin 7c which is pressed into the coinciding holes I1, by a spring l as soon as the head of the pin lo has quitted the slot m.

In order that the rising telescopic part may not carry with it the other telescopic part surrounding it by aid of friction, there is passed through all the parts, with the exception of the innermost, a pin a3, the inner end of which is rounded ofi". The rising tube presses this pin by means of its projection f\ outward to the extent of the thickness of one tube and thereby liberates the tube immediately surrounding it. The telescopic parts may have a circular or polygonal section, and the tube walls may be composed of net work.

The arrangement according to the present invention is adapted especially for the construction of jacks especially for automobiles for the purpose of which a corresponding diminution of the height dimensions must take place.

The spindle a instead of being revolubly supported in a casing c can be rigidly connected therewith and then by revolving this casing the spindle can be turned and thereby the extension of the telescopic parts be effected. In this case the casing c is' preferably supported by ball bearings upon a separate bed plate and moreover provided with spokes or with holes for the insertion of bars. v

I-Iaving now particularly described and ascertained the nature said invention and in whatmanner the same is to be performed, I declare that what I claim is:

A device of the kind described comprising in combination an outer casing, a number of telescopic parts in said casing, .a screw spindle placed in the interior of said telescopic parts, means for rotating said screw spindle, a female screw at the bottom-end of each of saidtelescopic parts and adapted to engage the screw-threaded portion of said screwspindle, a spring-governed bolt at the upper end of each of said telescopic parts adapted to engage a hole in the adjacent inner telescopic part before the latter leaves the top of said screw-spindle, means for disengaging said spring-governed bolts when said telescopic parts are retracted, and a spring governed bolt connected with said casing In witness whereof I have hereunto'signed and adapted to projectt-hrongh all sald telemy name this 23rd day of March 1911, in scopiopart-s with the exception of the innerthe presence of two subscribing witnesses.

most and to be pressed outward by the ris- ALEXANDER SIEWERT. 5 ing telescopic part to the extent of the thick- Witnesses:

ness of one of said telescopic parts, sub- HENRY HASPER,

stantially as set forth. WOLDEMAR HAUPT.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2662712 *Sep 21, 1950Dec 15, 1953Rose Louis CTelescopic mast
US2719016 *Apr 13, 1951Sep 27, 1955Howard E WicksAircraft landing gear
US2739673 *May 26, 1952Mar 27, 1956Foster Everett JAerial masts
US2814099 *Apr 29, 1953Nov 26, 1957Donald M KnittelCombination jack and work stand
US2819938 *Apr 30, 1954Jan 14, 1958Zerver Alfred MTool stand
US2908142 *Sep 28, 1956Oct 13, 1959De Long CorpSupporting leg assembly for marine platform
US2910883 *Feb 6, 1958Nov 3, 1959Jr Maurice T ReedAnti-friction force column
US2961837 *Sep 28, 1956Nov 29, 1960Delong CorpSupporting leg assembly for marine platform
US2984075 *May 15, 1956May 16, 1961De Long CorpInternal and external jack assembly for telescopic caissons
US2990587 *Mar 20, 1959Jul 4, 1961Fred Medart Mfg CoPower actuated movers for telescoping gymnasium seat-structures
US3011317 *Nov 29, 1956Dec 5, 1961Kerr Mc Gee Oil Ind IncSubmergible barge
US3064944 *Apr 12, 1961Nov 20, 1962West Michigan Steel Foundry CoLanding gear leg structure
US4023819 *Nov 11, 1975May 17, 1977Holman Jr Robert ESpring-loaded adjustable length cargo rod
US5282593 *Jun 5, 1992Feb 1, 1994Tri W-G, Inc.Adjustable leg
US5915877 *Jun 4, 1997Jun 29, 1999Quality Boat Lift, Inc.Positive drive boat lift
US5957623 *Feb 12, 1998Sep 28, 1999Quality Boat Lifts Inc.Electrically insulated positive drive boat lift
US6279860 *Mar 20, 2000Aug 28, 2001Brett A. SwangerHeat exchanger housing support
US7556227 *May 5, 2005Jul 7, 2009Miele & Cie. KgAdjustable screw foot for appliances
US8998159 *Feb 4, 2013Apr 7, 2015John Henry PearsonLocking system for adjustable telescopic props
US9388545 *Jan 29, 2014Jul 12, 2016J. Thomas WolnerDevice for raising and lowering a structure
US20050247834 *May 5, 2005Nov 10, 2005Markus ThueligAdjustable screw foot for appliances
US20130206948 *Feb 4, 2013Aug 15, 2013John Henry PearsonLocking System for Adjustable Telescopic Props
U.S. Classification254/103, 403/108, 405/198, 248/354.3
Cooperative ClassificationB66F3/16