US3824897A - Multispeed hydraulic or pneumatic device - Google Patents

Multispeed hydraulic or pneumatic device Download PDF

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Publication number
US3824897A
US3824897A US00342217A US34221773A US3824897A US 3824897 A US3824897 A US 3824897A US 00342217 A US00342217 A US 00342217A US 34221773 A US34221773 A US 34221773A US 3824897 A US3824897 A US 3824897A
Authority
US
United States
Prior art keywords
pressure
working chambers
pistons
piston
valve 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
US00342217A
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English (en)
Inventor
A Bryntse
K Berkestad
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.)
BYGG OCH TRANSPORTEKONOMI BI SW AB
BYGG OCH TRANSPORTEKONOMIE AB
Original Assignee
BYGG OCH TRANSPORTEKONOMIE AB
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 BYGG OCH TRANSPORTEKONOMIE AB filed Critical BYGG OCH TRANSPORTEKONOMIE AB
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Publication of US3824897A publication Critical patent/US3824897A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/204—Control means for piston speed or actuating force without external control, e.g. control valve inside the piston
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1409—Characterised by the construction of the motor unit of the straight-cylinder type with two or more independently movable working pistons

Definitions

  • a hydraulic or pneumatic device with a cylinder and piston system provides a rapid stroke and a power stroke.
  • the piston part of the system consists of two lengthwise integrally connected piston-rod like plunger pistons, with different diameters.
  • the cylinder is also provided with two working chambers, onefor each piston, each working chamber at least partly surrounding its own piston. In each the pistons there is a passage connecting the two working chambers.
  • the present invention relates to a hydraulic or pneumatic device including a cylinder and piston system for providing a rapid stroke'and a power stroke.
  • the device is especially although not exclusively intended for use in trucks for handling ofgoods,'e.g. pallet trucks.
  • Known pallet'trucks often have a fixed ratio between the movement of the pump piston and the movement of the lift piston.
  • the ratio is so choosen that, with maximum load onthe pallet truck, it is possible manually to effect the movements of the pump piston via a lever system.
  • the ratio is, therefore, not so effective when lifting light loads or when the truck is unloaded.
  • the unloaded condition occurs after the pallettruck is inserted under the load and before it has been pumped up into engagement with the load.
  • the height of this unloaded lift movement is dependent upon the shape of the pallet and usually varies between and 45 mm.
  • a ratio often used in pallet trucks is so choosen that one pump stroke gives about 10 mm movement of the lift piston.
  • the main object of the present invention is to provide a movement of the lift piston, which movement is automatically'dependent on load, thereby eliminating most of the disadvantage mentioned above.
  • the basic conception of the present invention invoices a cylinder together with the lift piston wherein two effective pistons of different diameter are formed in working chambers.
  • This two vdiameter'system provides lift forces almost everywhere along the whole length of the cylinder.
  • the construction is simple and economical and has a minimum number of movable parts.
  • the method is especially suitable for cylinders having'a relatively short lengthof stroke, e.g. cylinders in pallet trucks.
  • the piston and cylinder have outer dimensions in full conformity with conventional, well tested and well motivated structures.
  • Each piston isat least partly peripherically surrounded by its own working chamber in the cylinder.
  • a cylinder housing 1 includestwo integrally connected, longitudinally aligned I piston-rod like plunger pistons 5 and 6'. These pistons have different diameters, of which the leading plunger piston 5 is the largest.
  • the pistons 5 and 6 are practically sealed and guided in relation to the cylinder housing 1 by means of guides 3 and 4, and are arranged to run easily therein.
  • the lengths of the pistons 5 and 6 are such that, when the pistons are fully extended, they must still be guided by the guides 3 and 4.
  • the pistons 5 and 6 are further provided with a central bore 7, which together with passages 8 and 10, a ball 11, a valve seat 12 and a valve bore l3enables the pressure transmission medium (such as hydraulic fluid, for example) to pass from a first working chamber 14 to another longitudinally aligned working chamber 15, but not in the opposite direction, since the ball 11 is then sealed against the seat 12.
  • the leading piston 5 works in chamber 15 and the trailing piston 6 works in chamber 14.
  • the cylinder housing 1 also contains a reservoir 16 for the pressure transmission medium. Passages 17 and 18 enable the-flowof pressure transmission medium fromthe reservoir 16 to the working chamber 14, but not in the opposite direction, since a valve ball 19 is then sealed against a seat 20.
  • The'cylinder housing contains a further passage 21.
  • a known valve system (not disclosed here) can be connected to a pump during the pumping up and to the reservoir during the lowering.
  • the cylinder housing 1 contains a change over device in the form of a bore 29 and a valve comprising a hole 22, a ball-23, a piston 24, an O-ring 25, a spring 26' and a screw plug 27, provided with a hole 28.
  • the piston 24 with the O-ring 25 is easily movable in relation to the bore 29.
  • the spring loaded valve' is opened, the passage 21 is connected to the working chamber 14 viathe hole 22, the ball 23 and a passage 30.
  • the pressure transmission medium is pumped, via the valve system known per se, through the passage 21 and into the working chamber 15-and through the passages 8 and 10 into the bore 7, the ball 11 thereby, being sealingly pressed-against the'seat 12.
  • the communication between the passage 21 and the working chamber 14 is closed by the ball 23, which the spring 26 acting via the piston 24 sealingly presses against the opening of the hole 22.
  • This means that the pressure of the medium acts only on the area, which corresponds to the difference between the diameters of the pistons 5 and 6. Therefore these pistons will make a large movement in relation to the quantity of pressure medium supplied.
  • Pressure medium will also be drawn from the reservoir 16 through the passage 17, past the ball 19 and via the passage 18 into the working chamber 14.
  • the screw plug 27 is provided with thehole 28 in order to ensure, that atmospheric pressure always exists on the surface of the piston 24 which faces the spring 26. i
  • the above described change-over device may comprise other means than the described valve 23 29, e.g.
  • the change-over valve 23 29 is n0nsensitive to viscosity differences and can be substantially loss free.
  • the passage 21 is connected via the valve system known per se to the reservoir 16, in which there is substantially atmospheric pressure.
  • the cylinder can be driven with either gas or liquid as pressure medium.
  • a lifting device operated by a hydraulic or pneumatic pressure transmission medium comprising a piston and cylinder system for providing both a rapid stroke and a power stroke, acting in the same unidirection, the piston part of said system comprising two integral longitudinally aligned plunger pistons, the leading (with respect to the lifting direction) one of said plunger pistons having a larger diameter than the trailing one of said plunger pistons so that an annular shoulder is formed between the two pistons, said shoulder comprising a first pressure area acted upon by the pressure transmission medium, the trailing one of the pistons having another pressure area acted upon by the same medium, two separate and longitudinally aligned working chambers, formed in said cylinder-part of the system, the first of said working chambers containing said first pressure area and the second of said working chambers containing the other pressure area, means associated with each of said working chambers for supplying said pressure transmission medium thereto, valve means controlled by the pressure transmission medium comprising a pressure medium passageway formed in said pistons and connecting the two working chambers with each other

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Reciprocating Pumps (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Earth Drilling (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Load-Engaging Elements For Cranes (AREA)
  • Working Measures On Existing Buildindgs (AREA)
US00342217A 1972-03-24 1973-03-16 Multispeed hydraulic or pneumatic device Expired - Lifetime US3824897A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7203859A SE370267B (xx) 1972-03-24 1972-03-24

Publications (1)

Publication Number Publication Date
US3824897A true US3824897A (en) 1974-07-23

Family

ID=20263022

Family Applications (2)

Application Number Title Priority Date Filing Date
US00342216A Expired - Lifetime US3828650A (en) 1972-03-24 1973-03-16 Multispeed hydraulic or pneumatic device
US00342217A Expired - Lifetime US3824897A (en) 1972-03-24 1973-03-16 Multispeed hydraulic or pneumatic device

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US00342216A Expired - Lifetime US3828650A (en) 1972-03-24 1973-03-16 Multispeed hydraulic or pneumatic device

Country Status (14)

Country Link
US (2) US3828650A (xx)
JP (2) JPS5627725B2 (xx)
BE (2) BE796722A (xx)
CA (2) CA974431A (xx)
CH (2) CH545919A (xx)
DE (2) DE2314402A1 (xx)
DK (2) DK140058B (xx)
FI (2) FI57650C (xx)
FR (2) FR2178002B1 (xx)
GB (2) GB1382378A (xx)
IT (2) IT979982B (xx)
NL (2) NL7304144A (xx)
NO (2) NO138877C (xx)
SE (1) SE370267B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258609A (en) * 1977-10-11 1981-03-31 Conway John P Dual speed hydraulic piston assembly
US20060272497A1 (en) * 2005-05-12 2006-12-07 P. & M. Design & Consulting Ltd. Pneumatic cylinder
CN113606205A (zh) * 2021-08-04 2021-11-05 盾构及掘进技术国家重点实验室 一种基于分布式主动柱塞的tbm撑靴装置

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4392220A (en) * 1980-05-30 1983-07-05 Nippon Electric Co., Ltd. Modem to be coupled to a directional transmission line of an SS multiplex communication network
AT389079B (de) * 1988-05-19 1989-10-10 Engel Gmbh Maschbau Schliessmechanismus einer spritzgiessmaschine
JP2986696B2 (ja) * 1994-12-08 1999-12-06 シーケーディ株式会社 エアベアリングシリンダ及びシリンダシステム

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2049335A (en) * 1934-09-15 1936-07-28 William G Stephens Quick action hydraulic jack
US2284228A (en) * 1940-03-18 1942-05-26 Herbert E Page Pressure multiplying mechanism
US2532735A (en) * 1949-05-06 1950-12-05 American Steel Foundries Hydraulic press with auxiliary pump in cooling by-pass
CH338099A (fr) * 1957-08-26 1959-04-30 Charmilles Sa Ateliers Servo-mécanisme pour contrôler les déplacements d'une électrode dans une machine à électro-érosion
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2571658A (en) * 1946-07-22 1951-10-16 Hpm Dev Corp Multiple area piston means
GB654191A (en) * 1949-07-12 1951-06-13 Laycock Engineering Company Lt Improvements in or relating to hydraulic jacks, presses and like hydraulic apparatus
DE1765271U (de) * 1956-06-21 1958-04-17 Ludwig Rexroth Eilgangkolben.
DE2007711C3 (de) * 1970-02-19 1974-03-07 Michael Maurus 6710 Frankenthal Glas Kolbengetriebe mit Eilgang und Krafthub

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2049335A (en) * 1934-09-15 1936-07-28 William G Stephens Quick action hydraulic jack
US2284228A (en) * 1940-03-18 1942-05-26 Herbert E Page Pressure multiplying mechanism
US2532735A (en) * 1949-05-06 1950-12-05 American Steel Foundries Hydraulic press with auxiliary pump in cooling by-pass
CH338099A (fr) * 1957-08-26 1959-04-30 Charmilles Sa Ateliers Servo-mécanisme pour contrôler les déplacements d'une électrode dans une machine à électro-érosion
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4258609A (en) * 1977-10-11 1981-03-31 Conway John P Dual speed hydraulic piston assembly
US20060272497A1 (en) * 2005-05-12 2006-12-07 P. & M. Design & Consulting Ltd. Pneumatic cylinder
US7395749B2 (en) 2005-05-12 2008-07-08 Michael R Adams Pneumatic cylinder
CN113606205A (zh) * 2021-08-04 2021-11-05 盾构及掘进技术国家重点实验室 一种基于分布式主动柱塞的tbm撑靴装置
CN113606205B (zh) * 2021-08-04 2023-09-15 盾构及掘进技术国家重点实验室 一种基于分布式主动柱塞的tbm撑靴装置

Also Published As

Publication number Publication date
CH545919A (xx) 1974-02-15
FR2177999A1 (xx) 1973-11-09
BE796722A (fr) 1973-07-02
JPS496376A (xx) 1974-01-21
FI57650B (fi) 1980-05-30
NO138877B (no) 1978-08-21
DE2314403A1 (de) 1973-10-04
NL7304143A (xx) 1973-09-26
JPS496377A (xx) 1974-01-21
FI57649C (fi) 1980-09-10
BE796718A (fr) 1973-07-02
DK139937B (da) 1979-05-21
FI57649B (fi) 1980-05-30
DE2314402A1 (de) 1973-10-04
CH546347A (de) 1974-02-28
FR2178002A1 (xx) 1973-11-09
CA973064A (en) 1975-08-19
DK140058C (xx) 1979-11-12
NO140924B (no) 1979-09-03
JPS5627725B2 (xx) 1981-06-26
US3828650A (en) 1974-08-13
GB1382378A (en) 1975-01-29
NO138877C (no) 1978-11-29
FR2177999B1 (xx) 1976-04-23
DK140058B (da) 1979-06-11
IT979983B (it) 1974-09-30
NO140924C (no) 1979-12-12
FI57650C (fi) 1980-09-10
DK139937C (xx) 1979-10-22
IT979982B (it) 1974-09-30
SE370267B (xx) 1974-10-07
GB1380889A (en) 1975-01-15
NL7304144A (xx) 1973-09-26
FR2178002B1 (xx) 1976-04-23
CA974431A (en) 1975-09-16

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