US3828650A - Multispeed hydraulic or pneumatic device - Google Patents

Multispeed hydraulic or pneumatic device Download PDF

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Publication number
US3828650A
US3828650A US00342216A US34221673A US3828650A US 3828650 A US3828650 A US 3828650A US 00342216 A US00342216 A US 00342216A US 34221673 A US34221673 A US 34221673A US 3828650 A US3828650 A US 3828650A
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US
United States
Prior art keywords
piston
pressure
flow
transmission medium
chambers
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
US00342216A
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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 BT 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
Application granted granted Critical
Publication of US3828650A publication Critical patent/US3828650A/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

  • ABSTRACT A hydraulic or pneumatic device is provided with a cylinder and piston system for providing a rapid stroke and a power stroke.
  • the piston part of said system comprises a piston-rod like plunger piston, which at its lower end slidingly surrounds a tube extending upwardly from, but not secured to the bottom of the cylinder.
  • the cylinder is also provided with two working chambers, which at least partly peripherically surround said piston. Passages are formed in said piston and in said tube for connection of 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, in which system the piston slidingly surrounds a tube extending from the bottom of the cylinder.
  • the device is especially although not exclusively intended for use in trucks for handling goods, e.g. pallet trucks.
  • Known pallet trucks have a fixed ratio between the movement of the pump piston and the movement of the lift piston.
  • the ratio is so chosen that, with maximum load on the pallet truck, it is possible, via a lever sys' tern, manually to effect the movements of the pump piston.
  • the ratio is therefore not so effective when lifting light loads or when the truck is unloaded.
  • An unloaded conditions occurs before the pallet truck, inserted under the load, has been pumped up into engagement with the load.
  • the height of this unloaded lift movement is dependent upon the shape and dimensions of the pallet and usually varies between 15 and 45 mm.
  • a ratio often used in pallet trucks is so chosen that one pump stroke gives about 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.
  • a pressure transmission medium such as a hydraulic or pneumatic fluid
  • the lift piston has a central bore for sealingly and slidingly around the tube.
  • a further working chamber is provided inside the piston, which mounting the piston working chamber is used to effect a rapid lift.
  • an extension of the cylinder downwards is necessary to enable the medium to be supplied there.
  • the basic conception of the present invention is to give the cylinder together with .theliftpiston such a form, that two outer working chambers are formed in relation to the piston. This gives an opportunity to supply the pressure transmission medium almost everywhere along the whole length of the cylinder. Furthermore the construction will be simple and economical with a minimum number of movable parts. The method is especially suitable for cylinders having a relatively short length of stroke, e.g. cylinders in pallet trucks. The inventive supply of the medium makes it possible for a cylinder according to the invention to have outer dimensions in full conformity with conventional well tested and well motivated constructions.
  • the piston comprises a piston-rod like plunger piston workingin and being at least partly peripherically surrounded by two working chambers formed in the associated cylinder. These working chambers are connected by a passage formed in the plunger piston.
  • a cylinder housing 1 includes a piston-rod like plunger piston 5 with uniform diameter.
  • This piston is sealingly guided in relation to the cylinder housing 1 by means of upper and mid wall section guides 3 and 4 and is arranged to run easily therein.
  • Mid wall section 4 divides the cylinder into two peripheral chambers 14 and 16.
  • the piston 5 is further provided with a central bore forming a .working chamber 7.
  • a tube 2 which extends upwardly from the bottom of the cylinder housing 1, but is not secured thereto.
  • Flow control means are pivoted in the form of the piston bore 7, the inner passage through the tube 2, passages 8 and 10 in the piston S, passages 6 and 13 in the tube 2, a ball 11 and a valve seat 12, which enables the pressure. transmission medium to pass from a first working chamber 14 to another chamber 15, but precludes flow in the opposite direction, since the ball 11 then seals itself against the seat 12.
  • the cylinder housing 1 also contains a reservoir 16 for the pressure transmission medium and passages 17 and 18, which permit the pressure transmission medium to flow from the reservoir 16 into the working chamber 14, but not in the opposite direction, since a valve ball 19 then seals itself against a seat 20.
  • the cylinder housing contains a further passage 21, which can be connected through a valve system known per se, but not disclosed here, to the pump (not shown) during the pumping up and to the reservoir during the lowering.
  • the cylinder housing 1 contains a valve in a bore.291 the valve includes 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 bore 29.
  • the passage 21 is connected to the working chamber 14 via the hole 22, the ball 23 and a passage 30.
  • the pressure transmission medium is pressed, via the valve system known per se, through the passage 21 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 and the tube 2 being pressed against the bottom of the cylinder housing 1.
  • the pressure of themedium acts only inside the bore 7. Therefore, the piston 5 will receive a large movement in relation to the quantity transmission medium supplied to the bore 7.
  • the pressure transmission medium will also be drawn from the reservoir 16 through the passage 17, past the ball 19 and via thev passage 18 into the working chamber 14.
  • the pressure of the medium arrives at a value such that the total power acting on the sectional area of the hole 22 exceeds the spring power 26. Then the ball 23 is pressed from its seat and the pressure transmission medium has free access to the chamber, .which is formed by the bore 29 and the piston 24, and from this chamber via the passage 30 to theworking chamber 14. The ball 19 is now forced against its seat 20 to prevent the pressure medium fromflowing into the reservoir 16. The pressure of the medium is then immediately decreased to a value, which corresponds to the load on the piston 5 divided by the sectional area of that piston.
  • the screwplug'27 is provided with the hole 28 in order to ensure that atmospheric pressure always exists on the surface of the piston 24 which faces the spring 26.
  • the above described change-over device can use other means than the described valve 23 29, (e.g. valving may be accomplished through a small slot or the like), the pressure equalizing being made at a certain piston-rod load and pump speed. Such a system, however, is dependent on the viscosity of the pressure medium and causes losses through the choke which the slot represents.
  • the change-over valve 23 29 is nonsensitive to viscosity differences and can be substantially loss free.
  • the passage 21 is connected to the reservoir 16 via the valve system, known per se, there is substantially atmospheric pressure in reservoir 16.
  • the medium in the working chamber 14 is also able to flow to the reservoir 16 through the passages 6 and 13, past the ball 11, the inner passage through the tube 2, the bore 7, the passages 8 and 10, the working chamber and the passage 21.
  • a hydraulic or pneumatic lifting device comprising a piston and cylinder system for providing a rapid stroke and a power stroke, the piston of said system comprising a piston-rod like plunger having a lower end with a central co-axial bore surrounding a tube extending upwardly from the bottom of the cylinder of said system, said piston further being provided with two pressure areas located in two separate and axially aligned working chambers longitudinally spaced apart along the direction of the piston stroke, said cylinder being in communication with both of said pressure areas of said piston and having upper and mid wall sections in direct contact with the outer surface of said piston thereby forming two peripheral chambers around said piston, one of said peripheral chambers being a first working chamber and the other of said peripheral chambers being in communication with the other working chamber in said bore, each of said working chambers being provided with a supply line for a pressure transmission medium, one of said lines having therein valve means controlled by the medium transmission pressure, passage ways for said pressure transmission medium being formed in said piston and in said tube for interconnecting the two working chambers with each other,
US00342216A 1972-03-24 1973-03-16 Multispeed hydraulic or pneumatic device Expired - Lifetime US3828650A (en)

Applications Claiming Priority (1)

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

Publications (1)

Publication Number Publication Date
US3828650A true US3828650A (en) 1974-08-13

Family

ID=20263022

Family Applications (2)

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

Family Applications Before (1)

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

Country Status (14)

Country Link
US (2) US3824897A (de)
JP (2) JPS496377A (de)
BE (2) BE796718A (de)
CA (2) CA973064A (de)
CH (2) CH546347A (de)
DE (2) DE2314402A1 (de)
DK (2) DK139937B (de)
FI (2) FI57650C (de)
FR (2) FR2178002B1 (de)
GB (2) GB1382378A (de)
IT (2) IT979983B (de)
NL (2) NL7304144A (de)
NO (2) NO138877C (de)
SE (1) SE370267B (de)

Families Citing this family (6)

* 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
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
CA2507149A1 (en) * 2005-05-12 2006-11-12 P & M Design & Consulting Ltd. Pneumatic cylinder
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

Citations (3)

* 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
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Family Cites Families (6)

* 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
US2532735A (en) * 1949-05-06 1950-12-05 American Steel Foundries Hydraulic press with auxiliary pump in cooling by-pass
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.
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
DE2007711C3 (de) * 1970-02-19 1974-03-07 Michael Maurus 6710 Frankenthal Glas Kolbengetriebe mit Eilgang und Krafthub

Patent Citations (3)

* 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
US3134232A (en) * 1961-10-02 1964-05-26 Walker Mfg Co Jack

Also Published As

Publication number Publication date
NL7304144A (de) 1973-09-26
JPS496376A (de) 1974-01-21
CA974431A (en) 1975-09-16
NO138877C (no) 1978-11-29
DK140058C (de) 1979-11-12
FR2178002B1 (de) 1976-04-23
JPS496377A (de) 1974-01-21
DE2314402A1 (de) 1973-10-04
CA973064A (en) 1975-08-19
NO140924B (no) 1979-09-03
IT979983B (it) 1974-09-30
DE2314403A1 (de) 1973-10-04
US3824897A (en) 1974-07-23
IT979982B (it) 1974-09-30
BE796722A (fr) 1973-07-02
DK139937C (de) 1979-10-22
NO140924C (no) 1979-12-12
SE370267B (de) 1974-10-07
FI57649C (fi) 1980-09-10
FI57649B (fi) 1980-05-30
FR2177999B1 (de) 1976-04-23
FR2177999A1 (de) 1973-11-09
FR2178002A1 (de) 1973-11-09
GB1382378A (en) 1975-01-29
JPS5627725B2 (de) 1981-06-26
FI57650C (fi) 1980-09-10
BE796718A (fr) 1973-07-02
DK140058B (da) 1979-06-11
CH545919A (de) 1974-02-15
DK139937B (da) 1979-05-21
GB1380889A (en) 1975-01-15
NL7304143A (de) 1973-09-26
NO138877B (no) 1978-08-21
CH546347A (de) 1974-02-28
FI57650B (fi) 1980-05-30

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