FR2616489A1 - MULTIPLE CYLINDER WITH AT LEAST THREE SLIDING ELEMENTS AND TELESCOPIC ARROW BY APPLYING - Google Patents

Abstract

The invention relates to a multiple jack with at least three elements mounted to slide relative to each other. This jack comprises a first cylinder 1; a first piston 4 which defines in the first cylinder a first large chamber 5 and a first small chamber 6; a second cylinder 7 integral with the first piston 4, which passes through a bottom 3 of the first cylinder 1 delimiting the first small chamber 6; a second piston 9 which defines in the second cylinder a second large chamber 10 and a second small chamber 11; a piston rod 12 integral with the second piston 9, which passes through a bottom 8 of the second cylinder 7 delimiting the second small chamber 11; and a first passage 13, which provides permanent communication between the chambers 6 and 10; however, that the chambers 5 and 11 are capable of being connected, selectively 24, to a device 23 for supplying pressurized fluid and to an outlet 22 of pressureless fluid, by second and third passages. One application is the production of a telescopic boom for a crane.

Description

Multiple cylinder with at least three sliding elements and boom

  telescopic when applying.

  Multiple cylinders are already known, each having at least three elements slidably mounted relative to one another. When such a cylinder is adopted, it must be possible to control its operation and, in particular, to impose

  particular extension and retraction sequences desired.

  The invention proposes a jack of the aforementioned type, in which the following sequence is obtained, without the addition of a chain or return rope, or toothed wheels or return pulleys: in the proposed ram, the second element exits out of the , or enters the third element, at the same speed as, and simultaneously with, the output of the first element out of, or at the entrance of, this first element in the second element, or at a proportional speed

  to that of said output of the first element.

  An interesting application of such a jack is the realization of a telescopic crane boom comprising at least three sections whose relative movements can thus be controlled very simply by a single cylinder and according to the desired sequences. The invention therefore firstly relates to a multiple cylinder which comprises a first cylinder; a first piston, which is slidably mounted within the first cylinder and which defines therein a first large chamber, of large useful section, and a first small chamber, of small useful section; a second cylinder, which is integral with the first piston and which passes through a bottom of the first cylinder defining the first small chamber; a second piston, which is slidably mounted inside the second cylinder and which defines therein a second large chamber, of large useful section, and a second small chamber, of small useful section; a piston rod, which is integral with the second piston and which passes through a bottom of the second cylinder delimiting the second

  small room; and a first pass, which realizes the communi-

  between the first small room and the second large room, while the first large room and the

  second small room are likely to be connected, selectively

  to a device for supplying pressurized fluid and

  to an escape of fluid without pressure, and conversely, respecti-

  second and third passages.

  The following advantageous provisions are furthermore preferably adopted: the second passage is constituted by a first duct, which is integral with the first piston, passes through this first piston, opens into the first large chamber and is mounted with telescopic sliding watertight by relative to a second duct which is secured to the second piston, passes through the second piston and opens into the second large chamber; -the second duct is disposed inside the piston rod; - The third passage is constituted by a third conduit, which is formed in the piston rod, extends inside the second piston and opens into the second small chamber. The invention also more particularly relates to a telescopic boom having a first section, internal, a second section, intermediate, inside which the first section is slidably mounted, and a third section, external, inside. which the second section is slidably mounted, while a cylinder as described above is mounted longitudinally within said three sections, the first cylinder being secured to the first section, the second cylinder being secured to the second section and the piston rod

  being attached to the third section.

  Preferably, the first cylinder is fixed on the inner end of the first section, the second cylinder is fixed on the inner end of the second section and the piston rod is fixed on the part of the third section, which is opposite to the axial opening of this third section by Laquelle

enters the second section.

  The main advantage of the invention lies in the possibility of obtaining simultaneous displacements and at equal relative speeds of the elements of the jack, and boom sections, without having recourse to complicated mechanical assemblies, heavy,

expensive and fragile.

  The invention will be better understood, and features

  secondary ticks and their benefits will become apparent during

  description of an embodiment given below by way of example.

  It is understood that the description and the drawing are not

  given as indicative and not limiting.

  Reference will be made to the accompanying drawing, in which the single figure is a schematic axial section of a jack and

  of a telescopic boom according to the invention.

  The jack shown in the figure comprises: - a first cylinder 1 having at each end a bottom 2, 3; a first piston 4, which is slidably mounted inside the first cylinder 1 and which delimits, in cooperation with the bottom 2, a first large chamber 5 of large useful section S5, and, in cooperation with the bottom 3, a first small chamber 6 of small useful section S6 (less than the useful section S5);

  a second cylinder 7 which comprises, at one end

  mity, a bottom constituted by the first piston 4 and, at the other end, a bottom 8 which is integral with the first piston 4, and which passes through with seal 3b the bottom 3 of the first cylinder 1 which, in cooperation with the first piston 4, defines the first small useful chamber 6; a second piston 9, which is slidably mounted inside the second cylinder 7 and which delimits therein, in cooperation with the first piston 4, a second large granular chamber of useful section S10, and, in cooperation with the bottom 8 of the second cylinder, a second small chamber 11 of small useful section S11 (less than the useful section S10);

  a piston rod 12, which is integral with the second -

  piston 9 and which passes through 8b with the bottom 8 of the second cylinder, which, in cooperation with the second piston 9, defines the second small chamber 11; - A first passage 13, which is formed in the first piston 4 and which carries out the permanent communication of the second large chamber 10 with the first small chamber 6; a second passage, constituted by a first conduit 14, integral with the first piston 4, passing through this first piston (hole 15) and thus opening into the first large chamber 5, and by a second conduit 16, secured to the second piston 9, contained in the piston rod 12, passing through this second piston (hole 17) and opening into the second large chamber 10, the first duct 14 sliding with sealing 17b inside said second duct 16; and a third passage, which is constituted by a third conduit 18 formed inside the piston rod 12, and by a fourth conduit 19 formed in the second piston 9 and permanently connecting the third conduit 18 to the second

small room 11.

  The second conduit 16 and the third conduit 18 open out of the piston rod 12 by connectors

, 21, respectively.

  The supply circuit of the jack is itself constituted by: - a fluid reservoir 22; a pump 23; a three-position distributor 24; a calibrated discharge valve 25; the suction duct 26 and the discharge duct 27 of the pump 23, which connect it to the tank 22 and to the distributor 24, respectively; ducts 28 and 29, which connect the distributor 24 to the connectors 20, 21, respectively; a conduit 30, which connects the distributor 24 to the reservoir 22; and a duct 31 which connects the discharge duct 27 to the tank 22 and on which the discharge valve is placed

rated 25.

  The three positions of the distributor 24 correspond to: the first position, the communication between conduits 27 and 28, and conduits 29 and 30; - The second position, the closure of the ducts 28 and 29, and the placing in communication conduits 27 and 30; and - the third position, to porting

  ducts 27 and 29, and ducts 28 and 30.

  Furthermore, the jack is placed inside a telescopic boom with three sections, the axis 32 of the jack coinciding

  substantially with the axis of this arrow. -

  This consists of a first internal section 33, a second intermediate section 34 and a third external section 35, slidably mounted, the first section 33 inside the second section 34, into which it enters through an opening 34a, and the second section 34 inside the third section 35, into which it enters through an opening a. Sliding members, rollers or sliding pads, make these sliding possible. In the embodiment described, the rollers 36 and 37 are mounted inside the second section 34 and the third section 35, respectively, close to their respective openings, and rollers 38 and 39, mounted on the outside. outside the first section 33 and the second section 34, respectively, near their respective bottoms,

  opposed to the openings 33a and 34a of these sections.

  Note that the funds 3 and 8 of the first (1) and second (7) cylinders are extended by sails, which are fixed (3a, 8a) to the inner ends of the first (33) and second (34) sections of the boom telescopic and constitute the funds of these respective sections. Finally, opposite its opening 35a, the third section 35 is closed by a bottom 40, on which is fixed

  (41) the end of the piston rod 12.

  The section S10 of the second large chamber 10 is, in the embodiment described, equal to section S6 of the first

  6. Because these two chambers are in communi-

  permanent cation between them, and with no other chamber, the volume of fluid exiting one of these two chambers (or entering it) is necessarily received in the other chamber (or leaves). When the sections S10 and S6 are equal, this implies that the second cylinder 7 moves with respect to the second piston 9 at the same speed and simultaneously with the displacement of the first cylinder 1 with respect to the first piston 4. The outputs or the simultaneous recesses and at the same speed of the first section 33 of the boom relative to the second section 34, and the second section 34 relative to the third section 35, which is desirable for the application described telescopic crane arrows. The relative strokes C 33/34 and C 34/35 of the first section 33 with respect to the second section 34, and the second section 34 with respect to the third section 35 are

in addition equal.

  But it is understandable that it is enough to modify the ratio of the sections S6 / S10, for, for example, if the section S6 was equal to half of the section S10 IS6 = (S10) x 0.5 ?, obtain a speed of output, and a stroke, of the first section 33 with respect to the second section 34, equal to twice the exit speed, and the stroke of the second section 34 relative to the

third section 35.

  The actual control of the telescoping is the following: - for the output of the sections relative to each other, and the extension of the boom, the distributor 24 is placed in its first position: the fluid discharged by the pump 23 fills the first large room 5; the first piston 4 is close to the bottom 3 of the first cylinder 1; the fluid contained in the first small chamber 6 is driven out of this chamber and will fill the second large chamber 10; the second piston 9. is close to the bottom 8 of the second cylinder 7; and the fluid contained in the second small chamber 11 is expelled and, by the fourth 19 and third ducts 18, and the duct 29, returns to the reservoir 22; - For the return of the various sections and the retraction of the boom, the introduction of the distributor 24 in its third position causes the reverse displacements of those described in this

  which concerns the exit of these sections.

  The invention is not limited to the described embodiment, but covers all the variants that could be made without departing from its scope or its spirit.

Claims (6)

  1. Multiple cylinder with at least three elements mounted sliding relative to each other, characterized in that it comprises: - a first cylinder (1); - a first piston (4), which is slidably mounted inside the first cylinder and which delimits a first large chamber (5), of large useful section (S5), and a first small chamber (6), small useful section (S6); - a second cylinder (7), which is integral with the first piston (4) and which passes through a bottom (3) of the first cylinder defining the first small chamber (6); - a second piston (9), which is slidably mounted inside the second cylinder (7) and which delimits a second large chamber (10), of large useful section (S10), and a second small chamber (11) , of small useful section (Sll); - a piston rod (12), which is integral with the second piston (9) and which passes through a bottom (8) of the second cylinder (7) defining the second small chamber (11); and - a first passage (13), which carries out the permanent communication between the first small chamber (6) and the second large chamber (10); and in that the first large chamber (5) and the second small chamber (11) are connectable selectively (24) to a pressurized fluid supply and exhaust system (23) ( 22) of fluid without pressure, and vice versa,   respectively, by second and third passages.   2. Cylinder according to claim 1, characterized in that the second passage is constituted by a first duct (14), which is integral with the first piston (4), crosses (15) the first piston, opens into the first large chamber ( 5) and is telescopically slideably mounted with respect to a second duct (16) which itself is integral with the second piston (9), passes through (17) this second piston and opens into the second large chamber (10).   3. Jack according to any one of claims 1 and   2, characterized in that the second conduit (16) is disposed   inside the piston rod (12).   4. Jack according to any one of claims 1 to 3,   characterized in that the third passage is constituted. by a third duct (18), which is formed in the piston rod (12), extends (19) inside the second piston (9) and opens   in the second small room (11).   Telescopic boom comprising a first section (33) internal, a second section (34), intermediate, inside which the first section (33) is slidably mounted, and a third section (35) external to the interior of which the second section (34) is slidably mounted, characterized in that a cylinder according to any one of   1 to 4 is mounted longitudinally (32) to   inside the three said sections, the first cylinder (1) being integral (3a) of the first section (33), the second cylinder (7) being integral (8a) of the second section (34) and the piston rod   (12) being integral (41-40) of the third section (35).   6. Arrow according to claim 5, characterized in that the first cylinder (1) is fixed (3a) on the inner end of the first section (33), the second cylinder (7) is fixed (8a) on the end internal section of the second section (34) and the piston rod (12) is fixed (41) on the portion (40) of the third section (35), which is opposed to the axial opening (35a) of this third section   through which enters the second section (34).