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US 5,111,733 AGranted
Multiple stage hydraulic jack for use with telescopic jib
AssigneePPM, Inc.
InventorRobert Baraniak
Life of this patent
Estimating the term…
Abstract
This invention relates to a multiple jack incorporating at least three elements, viz. two pistons and two cylinders which define large and small chambers of a first cylinder, and large and small chambers of a second cylinder. According to the invention: a) a first inner conduit connects the large chamber of the first cylinder to a first outer conduit; b) a second inner conduit connects the small chamber of the first cylinder to a second outer conduit; c) a third inner conduit connects the large chamber of the second cylinder to a third outer conduit; and d) a fourth inner conduit connects the small chamber of the second cylinder to a fourth outer conduit. One application is the production of a telescopic jib presenting a satisfactory flexibility of use.
Claims16
A multiple jack comprising:
- a first cylinder;
- a first piston, mounted to slide inside the first cylinder, which defines therein a first large chamber, of large useful cross section, and a first small chamber, of small useful cross section;
- a first piston rod, which extends from the first piston, traverses a bottom of the first cylinder, to define the first small chamber of the first cylinder, and contains a cylindrical central first recess;
- a second cylinder which is constituted by the first recess of the first piston rod,
- a second piston, mounted to slide inside the second cylinder, which defines therein a second large chamber, of large useful cross section, and a second small chamber, of small useful cross section;
- a second piston rod which extends from the second piston and traverses a bottom of the second cylinder to define the second small chamber;
- a first inner conduit connecting the first larger chamber to a first outer conduit;
- a second inner conduit connecting the first small chamber to a second outer conduit;
- a third inner conduit connecting the second larger chamber to a third outer conduit;
- a fourth inner conduit connecting the second small chamber to a fourth outer conduit;
- the first large and first small chambers and the second large and small chambers are not connected by any link inside the jack;
- a first tubular conduit and a second tubular conduit, cylindrical, coaxial and distinct, extending from the first piston, a space separating the first and second tubular conduits, the first tubular conduit being contained in the second tubular conduit and comprising a cylindrical bore constituting a part of the first inner conduit;
- a third tubular conduit, extending from the bottom of the second piston rod and penetrating the space separating the first and second tubular conduits;
- two O-rings disposed between the second and third tubular conduits, the O-rings defining a chamber which communicates, via an orifice, with the interior of the third tubular conduit such that the cross sectional areas of the first tubular conduit and of the chamber are equal.
11 more elements
A multiple jack incorporating at least three elements mounted to slide with respect to one another, and a circuit for supplying pressurized fluid to such jack, comprising:
- a first cylinder;
- a first piston, mounted to slide inside the first cylinder, which defines therein a first large chamber, of large useful cross section, and a first small chamber, of small useful cross section;
- a first piston rod, which extends from the first piston, traverses a bottom of the first cylinder to define the first small chamber of the first cylinder, and contains a cylindrical central first recess;
- a second cylinder, which is constituted by the first recess of the first piston rod,
- a second piston, mounted to slide inside the second cylinder, which defines therein a second large chamber, of large useful cross section, and a second small chamber, of small useful cross section;
- a second piston rod which extends from the second piston and traverses a bottom of the second cylinder to define the second small chamber;
- a first inner conduit connecting the first large chamber to a first outer conduit;
- a second inner conduit connecting the first small chamber to a second outer conduit;
- a third inner conduit connecting the second large chamber to a third outer conduit;
- a fourth inner conduit connecting the second small chamber to a fourth outer conduit;
- a pump with delivery conduit;
- a discharge reservoir;
- a first fluid slide valve to which are connected the delivery conduit, a discharge conduit connected to the discharge reservoir, and the first and second outer conduits, with at least first and second positions, the first position corresponding to the communications of the delivery conduit with the first outer conduit and the second outer conduit with the discharge conduit, the second position corresponding to the obturation of at least one of the first and second outer conduits;
- a second fluid slide valve to which are connected the delivery conduit, a discharge conduit connected to the discharge reservoir, and the third and fourth outer conduits, with at least first and second positions, the first position corresponding to the communications of the delivery conduit with the third outer conduit and the fourth outer conduit with the discharge conduit, the second position corresponding to the obturation of at least one of the third and fourth outer conduits;
- a two-position slide valve assembly interposed on the second outer conduit and the fifth outer conduit, the twoposition slide valve assembly separating the second outer conduit into a first portion connected to the jack and a second portion connected to the first fluid slide valve, the two-position slide valve assembly separating the fifth outer conduit into a first portion connected to the fourth outer conduit and a second portion connected to the second portion of the second outer conduit, a sixth outer conduit connecting the third outer conduit to the two-position slide valve assembly, the first position of the twoposition position slide valve assembly enabling the communication of the first and second portions of the second outer conduit, the obturation of at least one of the first and second portions of the fifth outer conduit, and the obturation of the sixth outer conduit, the second position of the two-position slide valve assembly enabling the obturation of the second portion of the second outer conduit, the communication of the first portion of the second outer conduit with the sixth outer conduit, and the communication of the first portion of the fifth outer conduit with the second portion of the fifth outer conduit.
12 more elements
Dependencies are inferred from the claim text.