FR2783286A3 - HYDRAULIC UNIT - Google Patents

Abstract

Hydraulic unit (10) formed by a cylinder (12) guiding a piston rod (14). An inner tube (16) is provided in the piston rod (14). This tube is open towards the inner front surface of the piston rod (14) and is connected to a base (22) of the cylinder (12) to form a first hydraulic chamber outside of the piston rod (14) and a second hydraulic chamber inside the piston rod (14), these two chambers being independent.

Description

I

  The present invention relates to a hydrau-

  lique comprising a cylinder and a guided piston rod

in the cylinder.

  To lift heavy loads, for example vehicles, using a hydraulic unit or jack,

  often require additional safety supports.

  This is particularly true if staff have to stay under

charging or working on it.

  The retractable supports known hitherto required

  have external mechanical locking systems,

  or even additional hydraulic units.

  These solutions are technically complicated.

  is costly and therefore expensive; moreover, they are relati-

  bulky when often the place is not

  available, especially in vehicle lifting installations

automobile cars.

  The present invention aims to develop a hydraulic unit corresponding to the type defined above, allowing, with simple technical means, to achieve

  inexpensive and space-saving security support.

  To this end, the invention relates to a hy-

  hydraulics of the type defined above, characterized in that an inner tube housed in the piston rod, is open towards the internal front surface of the piston rod and is connected to a base of the cylinder to form a first hydraulic chamber at the outside of the piston rod and a second hydraulic chamber independent of the first inside

of the piston rod.

  Hydraulic unit with double cylinder according to

  the invention having two totally independent hydraulic chambers

  pendant, guarantees that always at least one hydrau-

  lique retains the hydraulic pressure used for the movement because a simultaneous failure of the two chambers

  hydraulic is practically impossible.

  To guarantee separate arrival and evacuation,

  the two rooms are provided with an appropriate connection.

  To avoid sagging if the pressure in a chamber disappears, the first connection and / or the second connection can be connected each time by

  through a non-return valve.

  If the two connections are connected to a non-return valve, it does not matter which of the hydraulic chambers has lost tightness because the other chamber will receive

then always the whole load.

  To make longer strokes, it is advantageous to place a telescopic tube between the cylinder and the piston rod and to connect it to the first hydraulic chamber and to have between the lower tube and the wall

  outside of the piston rod, a telescopic inner tube

  that connected to the second hydraulic chamber.

  As the two cylinder devices are coaxial, this creates neither rotation torque nor additional tilting torque, as is for example the case

  in the state of the art, when we have another hy-

  hydraulics outside the main cylinder to serve

security support.

  In addition, the construction is very space-saving

  and it is advantageously used for telescopic cylinders

  ques. Although the hydraulic unit according to the invention can be used in many fields, this unit is

  particularly interesting in its application to pla-

vehicle lifting forms.

  To adapt to different connection points of

  loads to be lifted, the hydraulic unit can be mobile ho-

  horizontally. The present invention will be described below from

  in more detail using two examples of realizations

  tion of the invention shown schematically in the

attached sins in which:

  - Figure 1 is a first example of realization

  tion of a hydraulic unit with a two-circuit safety support,

  - Figure 2 shows a second example of reali-

  sation of a hydraulic unit with a safety support to

  two circuits as telescopic cylinder.

  According to Figure 1, a hydraulic unit 10 consists of a cylinder 12 in which slides a piston rod 14 in the form of a hollow cylinder, under the action of the

hydraulic pressure.

  The bottom of the cylinder 12 has a base 22 to which an inner tube 16 is integrally connected housed at

  inside the piston rod 14.

  This inner tube 16 is sealed relative to the

  piston rod 14 so as to form a first hy-

  hydraulics outside the piston rod 14 and a se-

  hydraulic chamber inside the piston rod

  14, the latter being completely independent of the first

1st hydraulic chamber.

  The two hydraulic chambers are provided with a first connector 18 and a second connector 20 for

  supply and discharge of hydraulic fluids.

  Although this is not shown in FIG. 1, the first connection 18 and / or the second connection 20

  may include a non-return valve.

  These non-return valves not shown are for

  function of receiving the collapse pressure in the event of

  failure of one of the two hydraulic chambers.

  The displacement movement of the piston rod 14 can be done either by supplying pressurized hydraulic liquid through the first connection 18; in this case, the hydraulic fluid from the second hydraulic chamber inside the piston rod 14 is simply aspirated without being pressurized. But the operation can also

be reversed.

  Another possibility is to provide the li-

  hydraulically pressurized by the two connections 18,

, according to an appropriate dosage.

  Figure 2 shows a variant of a hy-

hydraulics 110.

  This hydraulic unit 110 differs from

  the hydraulic unit 10 of FIG. 1 by its telescopic shape

  than. Figure 2 shows the parts identical to those of Figure 1, bearing the same references increased by 100. The hydraulic unit 110 consists of a cylinder 112 guiding a piston rod 114. An inner tube 116 is housed in the rod piston 114; this tube is open towards the inner front face of the piston rod 114 and it is

  securely connected to the base 122 of the cylinder 112. We thus form

  if a first and a second hydraulic chamber which can

  wind receiving hydraulic fluid through a first connection 118 and a second connection 120; leaving the

  hydraulic fluid can be done by the same connections.

  To extend the stroke of the hydraulic unit, in particular of the piston rod 114, a telescopic tube 124 is provided between the cylinder 112 and the piston rod 114; this telescopic tube is also connected to the first

hydraulic chamber.

  In addition, inside the piston rod 114, between the inner tube 116 and the inner wall of the piston rod 114, there is provided a telescopic inner tube.

  126 connected to the second hydraulic chamber.

  In this second exemplary embodiment according to the

  Figure 2, the first branch 118 and / or the second branch-

  ment 120 can be connected to a non-return valve.

  The rest of the operation of the hydraulic cylinder of Figure 2 corresponds to that of the hydraulic unit of Figure 1, which allows not to perform

detailed description.

  The double cylinder having two hydraulic chambers

  that totally independent always guarantees that in case of failure of one room, the other room takes over all

  charge. If in addition each of the connections is fitted with a

  pet non-return, it doesn't matter which of the two

rooms lost its tightness.

  As the two cylinders are coaxial, there can be no rotation and / or tilting torque. In addition, the construction is very space-saving because no additional protection is required which would be located

  the exterior of the main unit.

NOMENCLATURE

  hydraulic unit 12 cylinder 14 piston rod 16 interior tube 18 1st connection 2nd connection 22 base hydraulic unit 112 cylinder 114 piston rod 116 interior tube 118 1st connection (3) 2nd connection (4) 122 base 124 telescopic tube 126 telescopic interior tube

Claims (6)

R E V E N D I C A T I ON S   1) Hydraulic unit (10, 110) comprising a cylinder (12, 112) and a piston rod (14, 114) guided in the cylinder, characterized in that an inner tube (16, 116) housed in the rod piston (14, 114) is open to the inner front surface of the piston rod (14, 114) and is connected to a base (22, 122) of the   cylinder (12, 112) to form a first hydraulic chamber   that outside the piston rod (14, 114) and a   independent hydraulic chamber from the first to   inside the piston rod (14, 114).   2) Hydraulic unit (10, 110) according to claim 1, characterized in that the first hydraulic chamber can receive or evacuate hydraulic liquid through a first connection (18, 118) and the second hydraulic chamber can by a second connection (20, 120).   3) Hydraulic unit (10, 110) according to claim 2, characterized in that the first and / or the second connection (18, 118; 20, 120)   are connected to a non-return valve.   4) hydraulic unit (110) according to one of claims 1   to 3, characterized in that a telescopic tube (124) provided between the cylinder (112) and   the piston rod (114) is connected to the first hy-   hydraulic, and between the inner tube (116) and the inner wall of the piston rod (114) a telescopic inner tube (126) is   connected to the second hydraulic chamber.   5) Application of a hydraulic unit (10, 110) according to one   any of claims 1 to 6, for platforms   motor vehicle lifters.   6) Application according to claim 7, characterized in that   the hydraulic unit (10, 110) is movable horizontally.