US2569821A - Collapsible roof crane - Google Patents

Collapsible roof crane Download PDF

Info

Publication number
US2569821A
US2569821A US14083A US1408348A US2569821A US 2569821 A US2569821 A US 2569821A US 14083 A US14083 A US 14083A US 1408348 A US1408348 A US 1408348A US 2569821 A US2569821 A US 2569821A
Authority
US
United States
Prior art keywords
pipe
jib
roof
crane
upright
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US14083A
Inventor
Maxeiner Elmer Fredrick
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US14083A priority Critical patent/US2569821A/en
Application granted granted Critical
Publication of US2569821A publication Critical patent/US2569821A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66FHOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F15/00Crowbars or levers
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66CCRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/18Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes
    • B66C23/20Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes with supporting couples provided by walls of buildings or like structures
    • B66C23/205Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes specially adapted for use in particular purposes with supporting couples provided by walls of buildings or like structures for use on top of roofs

Definitions

  • This invention relates generally to portable cranes, and more particularly to such cranes that are used by roofers and other workmen to hoist supplies and materials to a higher level from some point therebelow, and has as its principal object to so construct such a crane that it will be extremely simple and of a minimum number of members.
  • Another important object i to provide such a crane that it will be relatively light in weight and yet sturdy enough to withstand the loads to which it may ordinarily be subjected.
  • a further object of the invention is to provide a collapsible or knock-down portable crane, which will be self-supporting or retaining in operative position, so that no bolts, screws nor similar fastening elements need be used to anchor the mechanism in place.
  • An added object of my invention is to so construct such a device that it may be formed of pipe lengths to consist of but two units or members, so that these members may be interlocked together to be set up into operative position, and may be quickly and easily separated into the two units for removal from the job when no longer needed.
  • Another added object of the invention is to so construct the jib member of the mechanism so that any of the various materials used on the job, such as roofing paper, bags of cement, or any other relatively heavy work materials may be deposited on the lowermost end of the jib member to add sufficient weight to anchor the jib-member to the supporting wall or roof.
  • Still another object of the invention is to so construct the mechanism of the kind described,
  • Figure 1 is a perspective view showing the device as set up in operative position, showing the loading articles in dotted lines;
  • Figure 2 is a diagrammatic side elevation showing the cooperation of the parts of the device
  • Figure 3 is a fragmentary detail showing the adjustable positioning of the upright member upper end to the inclined jib member
  • Figure 4 is a fragmentary detail showing the detachable interlocking of the upper end of the
  • Figure 5 is a fragmentary side view, showing; the lower, trough end of the jib member, and. loaded slightly differently (in dotted lines) than;
  • l indicates any suitable: type of substantially horizontal supporting wall, such as a floor or a roof of a buliding structure, and to which or from which any kind of materials are to be carried.
  • the crane to be used for this manner of transportation between different levels be of light weight so that it can be most readily handled from job to job, and that it be of few members so as to avoid loss or misplacement of its parts, and in this particular instance I have been able to reduce the device to but two units or members, the same being indicated as the jib member 2 andthe upright or vertical supporting member 3 for detachable connection thereto.
  • the jib member 2 is preferably formed of an elongated length of hollow pipe of suitable diameter and strength so as to be able to withstand the loads to which the device may be subjected, without any bending or deformation of the same.
  • Thefcrward end of the pipe may have an eye bolt 4 extending thereinto and preferably welded in place so as to prevent any relative movement between th two, or any possible loss of the eye element, and the ropes, sheaves or other means may be carried by said eye element to support the load L suspended from the same.
  • the rear end of said jib pipe has a cross pipe 5 welded or otherwise rigidly secured thereto and to provide a. rounded bearing against the roof, this roundedbearing preventing the deep cute ting or other damage to the roof itself thereat.
  • a scoop, trough or other shape of frame 6 is;
  • the tierod When the device is being set up into operative position, as illustrated in Figs. 1 and 2, the tierod is swung about its lower end until the snap fastener pin can be detachably inserted through the proper opening 8 in the plate In.
  • the dotted line in Fig. 2 indicates the arc of swing of the tie-rod Hi.
  • the adjustments shown permit of shifting the jib member forwardly or rearwardly of the end of the roof being in position to hoist materials, and to change the angularity of inclination of the jib.
  • ahoisting mechanism consisting of a crane made of but two cooperating members, adjustably and ,de-
  • the upright member ⁇ isformed of; the upright pipe element H welded or otherwisesecured atits 'low'erend to a cross-pipe [2 so that thememe her-3; isin the form of aninverted,T the member' adapted to be supported on the roof by said; rounded shape ofthe pipe 12, of the T5; and provide a rounded. bearing with the roof insome what the same manner and;f9r the :same reasons; as that givenin connection-with,thecross pipe-5.
  • tie-rod. I6 is pivotally, securedi at; its, lower; end-tothe was, nd; of he pr s tel m neof: the uprightmember, theg'other; end of; said til?- rodbemein the or -e asnepr ast ner, av n 20 so that it extends rearwardly and; forwardly of t thesameican be set up into operative position in the shortest possible time, and which can be qdismantledi' or knocked down into collapsed inoperative position just as readily, and which perm-i-ts use of the materials closest at hand on the jo b, ,fo r; providing theweight W to anchor the rear end of the jib member in place without the use of bolts, screws, boards, or other extraneous fastening means which will mar and damage the roof, and when set up will lift the load L efficiently and satisfactorily.
  • said second member comprising an inclinedjpipe to, p ovid'e' aljib, means onfsaid inclinedpipe to adjustably interlock with the upper ends of said upright: pipe andwithsaid tie rod, a substantially-fcircue lar crossese'ctioned' transverse pipe fixed; to the. lower enchof saidjib pipe to-providea rounded bearing, thereat with said roof, andiaframejoni said lower end of said. jib pipe; and, extendingi transversely well asf orwardlyiand rearwardly oi .the;same to provide a,.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Civil Engineering (AREA)
  • Jib Cranes (AREA)

Description

1951 E. F. MAXEINER 2,569,821
COLLAPSIBLE ROOF CRANE Filed March 10, 1948 TTOBNE) Patented Oct. 2, 1951 UNITED STATES PATENT. OFFICE coL ArsmL ROOF CRANE Elmer Fredrick Maxe in'er, St. Louis, Mo. Application March 10, 1948, Serial No. 14,083
This invention relates generally to portable cranes, and more particularly to such cranes that are used by roofers and other workmen to hoist supplies and materials to a higher level from some point therebelow, and has as its principal object to so construct such a crane that it will be extremely simple and of a minimum number of members.
Another important object i to provide such a crane that it will be relatively light in weight and yet sturdy enough to withstand the loads to which it may ordinarily be subjected.
A further object of the invention is to provide a collapsible or knock-down portable crane, which will be self-supporting or retaining in operative position, so that no bolts, screws nor similar fastening elements need be used to anchor the mechanism in place.
An added object of my invention is to so construct such a device that it may be formed of pipe lengths to consist of but two units or members, so that these members may be interlocked together to be set up into operative position, and may be quickly and easily separated into the two units for removal from the job when no longer needed.
Another added object of the invention is to so construct the jib member of the mechanism so that any of the various materials used on the job, such as roofing paper, bags of cement, or any other relatively heavy work materials may be deposited on the lowermost end of the jib member to add sufficient weight to anchor the jib-member to the supporting wall or roof.
Still another object of the invention is to so construct the mechanism of the kind described,
that it will press downwardly against the roof at a pair of spaced intervals to anchor the mechanism thereat, the bearings at said anchorage intervals being arcuate or rounded so as not to 2 Claims. (Cl. 248-237) useful in various types of work and in various installations, and which will be otherwise satisfactory and eflicient for use wherever deemed applicable.
Many other objects and advantages of the con struction herein shown and described, and the uses thereof, will be'obvious to those skilled in the art to which this invention 'appertains, as will be more clearly apparent from the disclosures herein given.
To this end, my invention consists in the novel arrangement, construction and combination of parts herein shown and described, as will. be more clearly pointed out in the following specification.
In the drawings, wherein like reference characters represent like or corresponding parts throughout the views,
Figure 1 is a perspective view showing the device as set up in operative position, showing the loading articles in dotted lines;
Figure 2 is a diagrammatic side elevation showing the cooperation of the parts of the device;
Figure 3 is a fragmentary detail showing the adjustable positioning of the upright member upper end to the inclined jib member;
Figure 4 is a fragmentary detail showing the detachable interlocking of the upper end of the;
tierod with the jib member; and
Figure 5 is a fragmentary side view, showing; the lower, trough end of the jib member, and. loaded slightly differently (in dotted lines) than;
in Fig. l.
Referring more particularly to the drawings. wherein I have illustrated a preferred embodimentof my invention, l indicates any suitable: type of substantially horizontal supporting wall, such as a floor or a roof of a buliding structure, and to which or from which any kind of materials are to be carried.
It is very desirable that the crane to be used for this manner of transportation between different levels, be of light weight so that it can be most readily handled from job to job, and that it be of few members so as to avoid loss or misplacement of its parts, and in this particular instance I have been able to reduce the device to but two units or members, the same being indicated as the jib member 2 andthe upright or vertical supporting member 3 for detachable connection thereto.
struts l3-l 3.
The jib member 2 is preferably formed of an elongated length of hollow pipe of suitable diameter and strength so as to be able to withstand the loads to which the device may be subjected, without any bending or deformation of the same. Thefcrward end of the pipe may have an eye bolt 4 extending thereinto and preferably welded in place so as to prevent any relative movement between th two, or any possible loss of the eye element, and the ropes, sheaves or other means may be carried by said eye element to support the load L suspended from the same.
The rear end of said jib pipe has a cross pipe 5 welded or otherwise rigidly secured thereto and to provide a. rounded bearing against the roof, this roundedbearing preventing the deep cute ting or other damage to the roof itself thereat. A scoop, trough or other shape of frame 6 is;
4 upright pipe II when the crane is in knock-down form.
When the device is being set up into operative position, as illustrated in Figs. 1 and 2, the tierod is swung about its lower end until the snap fastener pin can be detachably inserted through the proper opening 8 in the plate In. The dotted line in Fig. 2 indicates the arc of swing of the tie-rod Hi.
The adjustments shown permit of shifting the jib member forwardly or rearwardly of the end of the roof being in position to hoist materials, and to change the angularity of inclination of the jib.
Thus, it is seen that 'I have provided ahoisting mechanism consisting of a crane made of but two cooperating members, adjustably and ,de-
tachably interlocking with one another so that fixed to and carried by the rear or lowermostend V of the jib pipe, as by bending a length of pipe the cross pipe 5, and also extends cross-wise or transversely of the jib pipe, somewhat as shown,
' imposed, while Figure 5, showstheJiSe of fewer rolls of paper in" addition tdthe bag of material, in'place. f r a V a l wo sets of adjustment opening 1 and 8 re spectively, are positioned at separated intervals along the length of the jib pipe the openings- T being} in a plate 9 welded, or otherwise rigidly secured to the. jib pipe near the forwardend of said ipe; while the? series of; openings 8v are. spaced apart in the plate; lo similarly secured to said jib pipe between. the plate; 9 I and the rear end of saidjib pipe. I V H i The upright member} isformed of; the upright pipe element H welded or otherwisesecured atits 'low'erend to a cross-pipe [2 so that thememe her-3; isin the form of aninverted,T the member' adapted to be supported on the roof by said; rounded shape ofthe pipe 12, of the T5; and provide a rounded. bearing with the roof insome what the same manner and;f9r the :same reasons; as that givenin connection-with,thecross pipe-5. A P of d al end n st ut interconnect or tie-in theupright pipe l l; r-with th e cross pipe I2, as by welding at the endspf said h upper n or umiehtpibfli isnrefer 'ably provided with a pair of ears l ll4 spaced;
apart av distance to receive -thecplate-s therebe tween, and isrpr vid df i h a. pinc r. belt; t5; transversely. r d pe man ntlr n la e asiuedicated so that said pin id is. adjustablyreceivedi w thinth e i of slots 1 of theplateiandi ears;
ain t e pp l sed ndei dislets h rea at to take up the load between;the-jibmember; and'upright member; 7 f
A: tie-rod. I6; is pivotally, securedi at; its, lower; end-tothe wer, nd; of he pr s tel m neof: the uprightmember, theg'other; end of; said til?- rodbemein the or -e asnepr ast ner, av n 20 so that it extends rearwardly and; forwardly of t thesameican be set up into operative position in the shortest possible time, and which can be qdismantledi' or knocked down into collapsed inoperative position just as readily, and which perm-i-ts use of the materials closest at hand on the jo b, ,fo r; providing theweight W to anchor the rear end of the jib member in place without the use of bolts, screws, boards, or other extraneous fastening means which will mar and damage the roof, and when set up will lift the load L efficiently and satisfactorily.
Having thus described my invention, it is obvious that various immaterial modifications may be made in thesame withoutdeparting from the spirit'of my invention; hence I do not wishto be understood as limiting. myself to the exact form, construction, arrangement or combination of parts herein shown and described, or the uses mentioned, except as limited by the state of the inventive art andthe claims hereunto appended.
Whatl claim as new and desire to se'curefby Letters Patent is:
1; In aportable knock-down roof crane con-. sisting. of two members, one of said members"; comprising an upright pipe, a substantially circular cross-sectioned transverse pipe fixed 'to' the lower end'of saidu'pright pipe'to provide a pivo tal bearing;e ngageable thereat with the roof,.
,tie rfod the'reaglainst into collapsed inoperative, position closely adjacent said pipe, said second member comprising an inclinedjpipe to, p ovid'e' aljib, means onfsaid inclinedpipe to adjustably interlock with the upper ends of said upright: pipe andwithsaid tie rod, a substantially-fcircue lar crossese'ctioned' transverse pipe fixed; to the. lower enchof saidjib pipe to-providea rounded bearing, thereat with said roof, andiaframejoni said lower end of said. jib pipe; and, extendingi transversely well asf orwardlyiand rearwardly oi .the;same to provide a,. trough to receive roof ing material's, removablye deposited, thereon and; en l fih ra e her oijh 1 in a portable cranaadaptedftd be self- Suppqrtedinpperative positionorr a substantiallyhorizontal supporting surface and-consisting of; an, elongated; jib -pipe,- an upright pipe detachably; wneeeeeat t pp g em i r ne: means permanently secured to the reari end;of; ei tiib; p pe-an xt n in ,forw dsa r a weir th'ereat f rms p rm;tQ- em9va l a tic es: Qt r of e; ma ia t r sufiic ent weight, to; anchor, said ,jib pipelthereata tie red movably carriedv at its lower-'end by he 19m end; 9i; ai w i -Pi e -ea ewes.
- 6 out at an angle to said upright pipe or be super- REFERENCES CITED imposed relatively closely thereagainst to be sub- The following references are of record in the stantially oo-extensive therewith, locking means file of this patent:
carried at the upper end of said tie rod, and cooperating locking means intermediate the ends 5 UNITED STATES PATENTS of said jib pipe and on said upright pipe, where- Number Name Date by said first-mentioned locking means may be 681,837 Nichols Aug. 27, 1901 moved to detachably interlock with either of said 808,678 Peterson Jan. 2, 1906 cooperating locking means to hold said tie rod 1,942,925 Jenkins Jan. 9, 1934 either co-extensive with said upright pipe or at 10 2,156,862 Maugard May 2, 1939 an angle thereto. 2,446,093 Lambert July 27, 1948 ELMER FREDRICK MAXEINER.
US14083A 1948-03-10 1948-03-10 Collapsible roof crane Expired - Lifetime US2569821A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US14083A US2569821A (en) 1948-03-10 1948-03-10 Collapsible roof crane

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14083A US2569821A (en) 1948-03-10 1948-03-10 Collapsible roof crane

Publications (1)

Publication Number Publication Date
US2569821A true US2569821A (en) 1951-10-02

Family

ID=21763447

Family Applications (1)

Application Number Title Priority Date Filing Date
US14083A Expired - Lifetime US2569821A (en) 1948-03-10 1948-03-10 Collapsible roof crane

Country Status (1)

Country Link
US (1) US2569821A (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3671015A (en) * 1970-02-26 1972-06-20 Howard W Brown Portable hoisting unit
US4782962A (en) * 1982-02-16 1988-11-08 Hackworth Harry L Back packable portable unit
US4801117A (en) * 1988-01-25 1989-01-31 Building Access Products, Inc. Portable support boom for window washer
US5341898A (en) * 1993-08-19 1994-08-30 Morris Baziuk Foldable boom for mounting on a roof of a building
US5622237A (en) * 1995-10-30 1997-04-22 Rollgliss, Inc. Portable hoist system
US20030173149A1 (en) * 2002-03-18 2003-09-18 Anderson Preston L. Anchor point devices, systems and methods for use in fall protection
US20070210291A1 (en) * 2006-03-13 2007-09-13 David L. Bailey Portable winching system for spa placement
US20070267249A1 (en) * 2006-05-18 2007-11-22 Cullen David P Roof safety system
US20100068005A1 (en) * 2008-09-17 2010-03-18 Wurth Steven P Construction apparatus
US20140090927A1 (en) * 2012-10-02 2014-04-03 Honeywell International Inc. Variable-Height Attachment Point System for a Safety Harness
US10024488B2 (en) 2014-10-06 2018-07-17 Wurtec, Incorporated Three-beam construction apparatus
US20180346289A1 (en) * 2015-11-30 2018-12-06 Cockerill Maintenance & Ingenierie S.A. Maintenance method and system for solar receiver
US11105103B2 (en) 2019-10-04 2021-08-31 Global Bmu Access Technologies, Llc Portable davit

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US681337A (en) * 1901-04-29 1901-08-27 Abner J Chapman Hay stacking and loading device.
US808678A (en) * 1904-06-13 1906-01-02 John Peterson Hay and manure gatherer and loader.
US1942925A (en) * 1932-02-15 1934-01-09 Jenkins & Adair Inc Portable boom support
US2156862A (en) * 1935-03-20 1939-05-02 Maugard Adolfo Best Mount for cinema cameras, etc.
US2446093A (en) * 1947-02-10 1948-07-27 Edward J Lambert Hoist frame

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US681337A (en) * 1901-04-29 1901-08-27 Abner J Chapman Hay stacking and loading device.
US808678A (en) * 1904-06-13 1906-01-02 John Peterson Hay and manure gatherer and loader.
US1942925A (en) * 1932-02-15 1934-01-09 Jenkins & Adair Inc Portable boom support
US2156862A (en) * 1935-03-20 1939-05-02 Maugard Adolfo Best Mount for cinema cameras, etc.
US2446093A (en) * 1947-02-10 1948-07-27 Edward J Lambert Hoist frame

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3671015A (en) * 1970-02-26 1972-06-20 Howard W Brown Portable hoisting unit
US4782962A (en) * 1982-02-16 1988-11-08 Hackworth Harry L Back packable portable unit
US4801117A (en) * 1988-01-25 1989-01-31 Building Access Products, Inc. Portable support boom for window washer
US5341898A (en) * 1993-08-19 1994-08-30 Morris Baziuk Foldable boom for mounting on a roof of a building
US5622237A (en) * 1995-10-30 1997-04-22 Rollgliss, Inc. Portable hoist system
US20030173149A1 (en) * 2002-03-18 2003-09-18 Anderson Preston L. Anchor point devices, systems and methods for use in fall protection
WO2003080186A1 (en) * 2002-03-18 2003-10-02 Baccou-Dalloz Fall Protection Investment, Inc. Anchor point devices, systems and methods for use in fall protection
US7032710B2 (en) 2002-03-18 2006-04-25 Bacou-Dalloz Fall Protection, Inc. Anchor point devices, systems and methods for use in fall protection
US20070210291A1 (en) * 2006-03-13 2007-09-13 David L. Bailey Portable winching system for spa placement
US20070267249A1 (en) * 2006-05-18 2007-11-22 Cullen David P Roof safety system
US20100068005A1 (en) * 2008-09-17 2010-03-18 Wurth Steven P Construction apparatus
US8646224B2 (en) 2008-09-17 2014-02-11 Wurtec Elevator Products & Services Construction apparatus
US20140090927A1 (en) * 2012-10-02 2014-04-03 Honeywell International Inc. Variable-Height Attachment Point System for a Safety Harness
US9410332B2 (en) * 2012-10-02 2016-08-09 Honeywell International Inc. Variable height attachment point system for a safety harness
US10024488B2 (en) 2014-10-06 2018-07-17 Wurtec, Incorporated Three-beam construction apparatus
US20180346289A1 (en) * 2015-11-30 2018-12-06 Cockerill Maintenance & Ingenierie S.A. Maintenance method and system for solar receiver
US10584017B2 (en) * 2015-11-30 2020-03-10 Cockerill Maintenance & Ingenierie S.A. Maintenance method and system for solar receiver
US11105103B2 (en) 2019-10-04 2021-08-31 Global Bmu Access Technologies, Llc Portable davit

Similar Documents

Publication Publication Date Title
US2569821A (en) Collapsible roof crane
US9506267B2 (en) Method for supporting an upstanding mast
US3082843A (en) Demountable scaffolding for side mounting on columns
US8820807B2 (en) Container carrying apparatuses and related methods
US2623643A (en) Scaffold raiser and remover
US20070056802A1 (en) Scaffolding
CN209455933U (en) A kind of superimposed sheet lifting appliance for hoisting
US2432528A (en) Guy derrick
US4505397A (en) Apparatus for hoisting materials and placing concrete
DE102015102841A1 (en) test load
US7014011B1 (en) Scaffolding lift system
CN206530032U (en) Scaffold can be moved integrally
CN110259087A (en) Scaffold support structure and scaffold support system
US2288354A (en) Hoisting equipment
CN209163407U (en) A kind of detachable simple construction lifting platform
CN209815482U (en) Overhead hoist of aerated block
US2326983A (en) Scaffolding and apparatus therefor
CN206476686U (en) A kind of gate-type hoisting bracket
US961018A (en) Rigging or scaffold support.
US20020042981A1 (en) System for lifting and assembling re-bar cages
CA2518832A1 (en) Scaffolding
US2851170A (en) Loading mechanism
US983578A (en) Builder's crane.
AU646920B2 (en) A tripod
CN214432952U (en) Portable lifting appliance placing frame with adjustable lifting hook