US3806093A - Extendable mechanism - Google Patents

Extendable mechanism Download PDF

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Publication number
US3806093A
US3806093A US00304804A US30480472A US3806093A US 3806093 A US3806093 A US 3806093A US 00304804 A US00304804 A US 00304804A US 30480472 A US30480472 A US 30480472A US 3806093 A US3806093 A US 3806093A
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US
United States
Prior art keywords
links
pair
pantograph
hydraulic jack
pivot means
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
US00304804A
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English (en)
Inventor
F Itazu
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.)
KYB Corp
TOWASEISAKUSHO KK
Original Assignee
Kayaba Industry Co Ltd
TOWASEISAKUSHO KK
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 Kayaba Industry Co Ltd, TOWASEISAKUSHO KK filed Critical Kayaba Industry Co Ltd
Application granted granted Critical
Publication of US3806093A publication Critical patent/US3806093A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, 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
    • B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/24—Devices, e.g. jacks, adapted for uninterrupted lifting of loads fluid-pressure operated
    • B66F3/245—Devices, e.g. jacks, adapted for uninterrupted lifting of loads fluid-pressure operated comprising toggle levers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, 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
    • B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
    • B66F3/22—Lazy-tongs mechanisms

Definitions

  • the present invention relates generally to an extendable mechanism using a pantograph or cross linkage, and more particularly to an extendable mechanism best adapted for use as a lift.
  • Pantograph jacks and table lifters are typical lift devices using a pantograph or cross linkage.
  • a pantograph jack generally comprises a pantograph linkage and a screw threaded to the opposed joints of the link-- age. The spacing between the opposed joints may be increased or decreased by turning the screw.
  • a table lifter generally comprises a base and a table coupled to each other by a parallel or cross linkage. The table is lifted by a hydraulic hoist interposed between the base and the linkage. In both the pantograph jack and table lifter the maximum force required when the jack or lifter starts to lift because of their mechanisms. The lifting force is gradually decreased as the'jack or table lifter is lifted.
  • the lift speed is also fastest when the jack or table starts to lift and is gradually decreased as the jack or table is lifted.
  • the lifting force and the lift speed cannot be freely selected depending upon the purpose of use, so that the design for the conventional pantograph jacks and table lifters are extremely difficult.
  • One of the objects of the present invention is therefore to provide an improved extendable mechanism, using a pantograph or cross linkage which may be freely designed in order to provide any desired extending or lift force and speed or lift speed.
  • a pair of auxiliary links are hinged to a pair of main links of a pantograph or cross linkage at a suitable point between the two pin joints of each link, and an extending device such as a hydraulic jack is interposed between the pin joint of the pair of auxiliary links and the pin joint between said pair of main links.
  • the extending or lifting Lli force as well as the extending or lift speed may be freely selected over the full lift stroke by selecting the point at which the pair of auxiliary main links are hinged to the pair of links.
  • FIG. illustrates a pantograph jack l0 embodying the present invention, but it will be understood that the present invention may be also applied to various link- 2 ages.
  • the pantograph jack 10 generally comprises a hydraulic jack 12, which also serves as a base, a pair of lower links 14, a pair of upper links 16 and a saddle 18 for receiving a load.
  • a pair of flanges 22 are formed at both sides of a seat 20 of the hydraulic jack 12 in opposed relation.
  • Each of the lower links 14 comprises a pair of steel plates or the like whose lower ends are rotatably pivoted to the flanges 22 with pins 24.
  • Each of the upper links 16 comprises a channel-shaped steel member whose lower end is hinged to the upper end of the lower link 14 with a pin 26.
  • An elongated slot 34 is formed in the base of each channel-shaped upper link 16 in order to reduce the weight.
  • the upper ends of the pair of upper links 16 are rotatably coupled to each other through the saddle l8 and saddle plates 38 with pins 28. It should be noted that teeth 36 are formed at the upper ends of the upper links 16 and engaged with each other when assernbled.
  • the hydraulic jack 12 may be a conventional portable jack so that it will be briefly described in this specification. That is, the hydraulic jack 12 generally comprises a main body 40 which in turn comprises a tank and a cylinder tube, a ram 42 slidably fitted into the cylinder tube, a pump 44 for pumping the working oil from the tank in the main body 40 into the cylinder tube for thereby lifting the ram 42, and a pressure-relief valve 46 for returning the working oil from the cylinder tube to the tank for thereby lowering the ram 42. All of the above described component parts of the hydraulic jack 12 are mounted on the seat 20.
  • the pump 44 generally comprises a pump cylinder 48 fixed to the seat 20, a plunger 50 slidably fitted into the cylinder 48, and a coupling member 54 for receiving an operating lever 52.
  • the coupling member 54 is pivoted with a pin 62 to the plunger 50 and also connected at one end thereof to the seat 20 through a connecting plate 56 with pins 58 and 60.
  • a connecting member 64 securely fixed to the upper endofthe ram 42 of the hydraulic jack 12 has a pair of extensions 66 whose width is smaller than the spacing between the pair of steel members forming each lower link-14.
  • a pair of auxiliary links 68 which are the most important components of the present invention, are 'in the form of a yoke and have their one ends hinged with pins 30 to the extensions 66 of the connecting member 64 respectively, and their. other ends hinged with pins 32 to the lower links 14.
  • the pantograph consisting of the hydraulic jack 12, the lower and upper links 14 and 16 and the saddle 18 may always maintain its correct form so that the saddle 18 may be always maintained in the horizontal position.
  • a working oil source such as a hand or power pump may be disposed independently of the pantograph jack and hydraulically coupled through a tube or the like to a hydraulic cylinder interposed between the seat 20 and the connecting member 64, so that the pantograph jack may be remote-controlled.
  • the lower and upper links 14 and 16 cannot be completely contracted by their own weight.
  • return springs 74 may be connected, as shown in FIG. 2, between abase 70 upon which is mounted the hydraulic jack 12 and a pair of arms 72 extended from the connecting member 64.
  • the pins 24 coupling the lower links 14 to the seat of the hydraulic jack 12 will be referred to as a; the pins 26 coupling the lower and upper links 14 and 16 together, b; the pins 28 coupling the upper links 16 to the saddle 18, c; the pins 30 coupling the auxiliary links 68 to the connecting member 64, d; and the pins 32 coupling the lower links 14 to the auxiliary links 68, e.
  • the lift of the pantograph jack 10 is given by 4/ 6( 6 X2 1 4 e' l 7 6
  • the ratio of the stroke of the hydraulic jack 12 to the lift of the pantograph jack 10 is given by 4/16' 1 6
  • the ratio of the load exerted on the pantograph jack 10 to the load exerted on the hydraulic jack 12 is given by the law of conservation of energy (W alx W dy) by 4/ s'l 1 e )l If the distance equals the distance 1 y 4 6 and 1 2 4/ 6 It is seen that the stroke ratio y/x and the load ratio W1/ W are always equal, independently of the stroke x of the hydraulic jack 12.
  • a pantograph jack best adapted for the purpose of use may be freely designed by selecting a suitable'length for the auxiliary link 68 and. a position at which the auxiliary link 68 is connected to the lower link 14.
  • An extendible mechanism comprising a pantograph linkage including a pair of first links having first and second ends, a pair of second links also having first and second ends, first pivot means pivotably connecting said first ends of said first links, second pivot means pivotably connecting said second ends of said second links, and third pivot means pivotably connecting said second ends of said first links with said first ends of said second links;
  • auxiliary links having first ends which are pivoted to one another, and also having second ends;
  • said extendible device comprises a hydraulic jack.
  • said hydraulic jack comprises a base
  • said second pivot means comprises two second pivots each of which pivotably connects one of said second ends of said second links with said base of said hydraulic jack; further comprising a load-engaging saddle; and wherein said first pivot means comprises two vfirst pivots each of which pivotably connects one of said first ends of said first links with said saddle.
  • said hydraulic jack further comprises a ram having a free end portion, and a connecting member fixed to said free end portion; and further comprising a pair of auxiliary pivotseach pivotably connecting one of said first ends of said auxiliary links with said connecting member.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Transmission Devices (AREA)
  • Handcart (AREA)
  • Invalid Beds And Related Equipment (AREA)
US00304804A 1971-11-08 1972-11-08 Extendable mechanism Expired - Lifetime US3806093A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8824871A JPS5650141B2 (enrdf_load_stackoverflow) 1971-11-08 1971-11-08

Publications (1)

Publication Number Publication Date
US3806093A true US3806093A (en) 1974-04-23

Family

ID=13937537

Family Applications (1)

Application Number Title Priority Date Filing Date
US00304804A Expired - Lifetime US3806093A (en) 1971-11-08 1972-11-08 Extendable mechanism

Country Status (4)

Country Link
US (1) US3806093A (enrdf_load_stackoverflow)
JP (1) JPS5650141B2 (enrdf_load_stackoverflow)
DE (1) DE2254648C2 (enrdf_load_stackoverflow)
GB (1) GB1365026A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4055329A (en) * 1976-07-19 1977-10-25 Leisure Manufacturing Co., Inc. Scissors jack
US5364071A (en) * 1993-11-24 1994-11-15 Lu Chung Tai Scissor jack
US5421554A (en) * 1994-11-30 1995-06-06 Kun-Shan Hsu Jack assembly
US5603486A (en) * 1995-09-15 1997-02-18 Liu; Yang-Chou Frame-type car jack
US20050045396A1 (en) * 2003-08-27 2005-03-03 Kenneth Leitner Snowmobile elevation mechanism

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5373596U (enrdf_load_stackoverflow) * 1976-11-22 1978-06-20
US4206900A (en) 1977-08-01 1980-06-10 Borg-Warner Corporation Valve operator
JPS55155901A (en) * 1979-05-21 1980-12-04 Nippon Kiki Kogyo Kk Multistage fluid cylinder device
JP4434540B2 (ja) * 1999-10-12 2010-03-17 スナップ−オン・インコーポレーテッド 低レベルジャッキ
JP5231054B2 (ja) * 2008-03-14 2013-07-10 新明工業株式会社 リフター装置
CN102292278A (zh) * 2009-02-24 2011-12-21 株式会社日立医疗器械 升降机构以及医用床位装置
JP5312550B2 (ja) * 2011-10-18 2013-10-09 タマチ工業株式会社 歩行補助椅子

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR623956A (fr) * 1925-10-31 1927-07-05 Cric à parallélogramme articulé
US1902827A (en) * 1928-11-22 1933-03-28 Harry W Bolens Hydraulic jack
CA498883A (en) * 1953-12-29 P. Brown William Hydraulic scissors jack
DE1025811B (de) * 1953-11-17 1958-03-13 Gutehoffnungshuette Sterkrade Mehrteiliger Ausbaurahmen fuer den wandernden Grubenausbau
US3259369A (en) * 1964-11-12 1966-07-05 Ready Lift Mfg Co Load lifting apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR701394A (fr) * 1929-08-27 1931-03-16 Dispositif pour soulever les véhicules

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA498883A (en) * 1953-12-29 P. Brown William Hydraulic scissors jack
FR623956A (fr) * 1925-10-31 1927-07-05 Cric à parallélogramme articulé
US1902827A (en) * 1928-11-22 1933-03-28 Harry W Bolens Hydraulic jack
DE1025811B (de) * 1953-11-17 1958-03-13 Gutehoffnungshuette Sterkrade Mehrteiliger Ausbaurahmen fuer den wandernden Grubenausbau
US3259369A (en) * 1964-11-12 1966-07-05 Ready Lift Mfg Co Load lifting apparatus

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4055329A (en) * 1976-07-19 1977-10-25 Leisure Manufacturing Co., Inc. Scissors jack
US5364071A (en) * 1993-11-24 1994-11-15 Lu Chung Tai Scissor jack
US5421554A (en) * 1994-11-30 1995-06-06 Kun-Shan Hsu Jack assembly
US5603486A (en) * 1995-09-15 1997-02-18 Liu; Yang-Chou Frame-type car jack
US20050045396A1 (en) * 2003-08-27 2005-03-03 Kenneth Leitner Snowmobile elevation mechanism
US6913287B2 (en) 2003-08-27 2005-07-05 Kenneth Leitner Snowmobile elevation mechanism

Also Published As

Publication number Publication date
GB1365026A (en) 1974-08-29
DE2254648C2 (de) 1982-12-16
JPS5650141B2 (enrdf_load_stackoverflow) 1981-11-27
JPS4857067A (enrdf_load_stackoverflow) 1973-08-10
DE2254648A1 (de) 1973-05-17

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