FR2524593A1 - PNEUMATIC SPRING - Google Patents

Abstract

THE INVENTION RELATES TO A PNEUMATIC SPRING WHICH INCLUDES A MECHANICAL HELICOIDAL SPRING 3 WITHIN WHICH IS HOSED A CYLINDRICAL MEMBRANE 1 OF ELASTOMERIC MATERIAL WHICH COVERS A PLURALITY OF WIRES ARRANGED ACCORDING TO THE GENERATORS OF THE FORM. THE END EDGES OF MEMBRANE 1 ARE RETURNED AROUND THE END COILS OF THE HELICOIDAL SPRING, OR THE SPRING ALSO INCLUDES COVERS 11 FOR CLOSING THE BASES OF THE MEMBRANE.

Description

The present invention relates to an air spring, that is to say to

  a device comprising a flexible envelope presented in the form of a membrane

  and assembled with a tight seal with two rigid bodies, for example-

  full metal, and inside which is a fluid

  under pressure, especially pressurized air.

  We already know many types of springs

  tires and, in particular, there are already known

  pneumatic spells constituted by an envelope formed by an elastomeric membrane which envelops a structure

  resistant formed of rubberized fabrics, themselves

  laid with textile or metallic threads, the threads of different

  canvas rents being crossed between them, this structure being open at its two ends, to which the said envelope is assembled by a removable connection and with a seal that is tight to rigid bodies, in particular metallic by means of which the envelope is closed and the

  fixing the spring to the structure or to the machine to which

the spring must be associated.

  Air springs already known have

different disadvantages.

  The main disadvantages of pneumatic springs

  known ticks of the type briefly described above are

  the following A first drawback lies in the low pressure of

  service with which these known air springs must

  wind working, which does not exceed the value of 8 9 kg / cm 2 and this results in the large transverse dimension of the known air springs and in the impossibility of applying these known air springs to machines

  and the like subject to operating conditions

mentally severe.

  A second disadvantage of pneumatic springs

  naked lies in their unsatisfactory useful life,

  which manifests itself in an unsatisfactory duration of the envelope

  eg of flexible material which constitutes one of the essential elements

spring sentials.

  A third drawback that is encountered in

  known air springs lies in the need for ef-

  perform extremely precise machining in the area in which the flexible casing is connected to a tight seal with the rigid bodies of these springs.

  of high cost, following precise machining mention-

  born higher, and constant insecurity regarding

  identifies the seal in said assembly areas between

  the flexible envelope and the rigid bodies.

  The object of the invention is to eliminate all the

  the known air springs which have been

  listed above, in order to increase the allowable charges

  on air springs while reducing their dimensions and extending their useful life, and also allowing a wide possibility of variation in the response characteristics to the loads applied to these

pneumatic springs.

  The invention relates to a pneumatic spring characterized in that it comprises a substantially cylindrical membrane of elastomeric material which coats a structure

  resistant formed of a plurality of flexible wires and i-

  nextensibles arranged according to the generatrices of the form cy-

  lindrique and, in addition, rigid annular bodies

  spaced from each other, coaxial to the membrane and dis-

  placed around it, these rigid annular bodies

  being in contact with the outer surface of said mem-

  brane and the edge of the latter being assembled to the rigid annular bodies which are furthest from each other. The figures of the appended drawing, given by way of nonlimiting example, will make it easier to understand how the invention can be implemented. On these drawings,

  Figure 1 is a perspective view of a res-

  pneumatic outlet according to the invention; Figure 2 shows on an enlarged scale and in

  cut a detail of the air spring of figure 1.

  An air spring according to the general concept of

  the invention comprises an envelope open at two ends

  tees and formed of a substantially cylindrical membrane made of

  third elastomer or the like in which are embedded

  flexible and inextensible wires arranged substantially se-

  along the generators of the cylindrical shape, and, in addition, several rigid annular bodies which are in contact with the outer surface of the membrane and which

  act as straps of it.

  In addition, the most rigid annular bodies

  distant from each other are assembled to the formed membrane

  mant the envelope by the fact that the ends of this membrane are turned around said annular bodies

  and assembled to the outer face of the membrane.

  In this way, according to the general concept of the object of the invention, each of the extreme edges of the membrane joined to the rigid annular bodies furthest from each other forms a sealing ring which

  fits between two flanges so as to allow these

  to form a rigid body associated with the membrane.

  Figures 1 and 2 show a form

  me of making a membrane according to the invention which

  be within the limits of the above concept.

  As can be seen in FIGS. 1 and 2, the pneumatic spring comprises, on the one hand, an envelope 1

  open at two ends in elastomer material, which

  be a resistant structure formed by a set of wires 2,

  the envelope being provided with a strapping 3 which surrounds its sur-

  outer face, and, on the other hand, rigid bodies 4 which

  close the open ends of the envelope 1.

  More particularly, the envelope 1 has a

  substantially cylindrical shape and its outer wall pre-

  feels a ripple so as to give rise to a

  handles 5 separated from each other by grooves 6. The grooves 6, which have a helical appearance and give the handles 5 an equally helical appearance, and

  receive the turns of a helicoid of high resistance wire

  tance 7, that is to say of a metallic spring made of pro-

said, or a cable.

  The various turns of the wire helicold 7 are held in the grooves 6 by the presence of a band 8 which bears in its center against the turns of the wire helicoid 7 and the ends of which are assembled to the

  outer surface of envelope 1, for example by colla-

ge or the like.

  As mentioned above, the envelope

  1 is provided with a resistant structure formed of a plura-

wire 2.

  The wires 2, which are made of a flexible and inextensible material, for example glass fibers, nylon, steel or the like, are arranged substantially according to the

  generators of the cylindrical shape constituting the envelope

loppe 1.

  The ends of the casing 1 are assembled to the end turns of the wire helicold 7, designated

  by the reference 7 'in FIG. 2, and the mode according to-

  which this assembly is carried out is represented on the fig-

  re 2, on which the assembly has also been shown

  which connects the rigid bodies 4 to the envelope 1.

  As can be seen in Figure 2, each

  end of the envelope 1 is turned around the spi-

  re 7 'end of the wire helicoid 7 so that the edge 9 of the casing 1 thus forms a slot 10 in which this coil 7' is housed, the edge being preferably fixed to the outer surface of envelope 1

with adhesives.

  At the level of the 7 'turn, there are two bri-

  11 and 12 made of a rigid material, for example

  metallic. More particularly, the flange 12 is a flange in the shape of a circular crown which is housed inside the envelope 1 and has its outermost circumferential edge 13 folded inwardly of the envelope 1 so as to give birth to an annular groove

  intended to accommodate a 7 'turn part.

  The flange 11 is, on the contrary, constituted by a circular plate, the edge 14 of which is folded down, for the observer looking at FIG. 2, so as to form an annular groove serving to accommodate a part of

the 7 'turn.

  The flange 11 and the flange 12 are provided with through holes 15 with which bolts-16 are engaged to establish a removable connection between said flanges 11

  and 12, by clamping between these two flanges the coil 7 'and the

  veloppe 1 turned around this turn.

  As shown in Figures 1 and 2, the heli-

  colde in rigid wire 7 has a constant pitch and the turns

  are attached to the casing 1 encircled by the helicoid.

  However, this should not be considered in a limiting sense, in the sense that the pitch of the turns of the wire helicoid 7 can vary according to any law to thereby vary the characteristics of the air spring according to any law and, in in addition, the turns of the wire helicold 7 may not be fixed to the outer surface of the envelope 1 by connections

stable.

  According to an alternative embodiment not shown

  tee, but which also falls within the general concept of the pneumatic spring according to the invention, provision is made for replacing the helicoid in rigid wire 7 with a plurality of rigid annular bodies which can be assembled on the surface of the envelope 1 by stable bonds or simply be in contact with this envelope,

  housed in the hollows 6 of the ripple formed by the

velvet 1.

  Finally, whatever the form of realization

  tion provided, it is provided at the flanges 11 means

  not shown used to introduce and maintain a fluid

  under pressure, for example pressurized air, in

envelope 1.

  It appears from the description given above

  of some embodiments of an air spring according to the invention that with this spring, it is possible to achieve

the goals.

  Indeed, thanks to the presence of a reinforcing structure of the envelope 1 made of flexible and inextensible wires arranged according to the generatrices of the substantially cylindrical shape of this envelope 1, it is obtained that these wires have small radii of curvature in

  all spring load conditions.

  Since the resistance to stresses which is exerted by the casing 1 depends on the resistance

  to the stresses of the wires which form its resistant structure

  aunt and since the decrease in the radius of curvature that the wires can take increases proportionally

  the resistance to the stresses of these wires and, consequently

  quent of the envelope 1, it can be supported by the latter considerably higher pressures than those which can be supported by the envelopes of the already known pneumatic springs which, having a resistant structure made of fabrics with crossed wires, constrain these fabrics to take large radii of curvature, to reach the possibility of withstanding pressures of

work about 15 16 kg / cm 2.

  The description given above means that an air spring according to the invention is able to support loads significantly greater than those which can

  be supported by known pneumatic springs.

  In addition, the rigid wire helicold placed around

  of the outer surface of the casing 1 of the tire spring-

  matic, by constituting by itself a mechanical spring,

  is able to bear part of the burden on its own

  outer ge which acts on the air spring according to

  the invention and, in this way, the pneumatic spring

  lon the invention is therefore also able to sup-

  carry loads higher than he could

  wear due to the mere presence of the envelope 1.

  The explanation for the fact that we reach a greater

25.24593

  service life with the air spring according to the invention

  that with those of the known type lies in the fact that, the structure

  resistant structure of the envelope being made of a plurality of wires which are substantially parallel to each other and therefore without mutual contact, no slipping can occur.

  between the wires and this results in a notable re-

  resistance of the envelope to fatigue stresses and, consequently, by a longer duration of this envelope which results in a longer duration of the air spring

which has this envelope.

  Finally, the assembly between envelope 1 and

  the rigid bodies which, with this envelope, give birth

  air spring, does not require execution

high precision machining.

  Indeed, the inversion of the ends of the

  veloppe 1 around the extreme turns of the wire helicoid

  gives rise to a sealing ring which, in front of

  be clamped between two flanges which together constitute a rigid body, does not require to ensure the tightness of

  machining precision, neither for itself, nor for the flanges.

  Ultimately, with this type of assembly between the

  veloppe 1 and the flanges, it is not necessary, like.

  indicated in the particular embodiment illustrated by the drawings and described above to make the connection

  between the extreme edge of the envelope 1 and the outer surface

  of this envelope due to the fact that during the

  tightening the pairs of flanges against the material of the enclosure

  loppe wound on the extreme turn, this material is blocked

  as friction between the surface of the flanges and the sur-

  face of the extreme turns of the wire helicoid, and this

  drags a notable simplification of the construction of the

  pneumatic fate In addition, this type of connection between the

  veloppe 1 and the flanges are very robust and

  also guarantees excellent watertightness

  under pressure housed in the casing in all

  working conditions of the air spring.

  It goes without saying that modifications may be made to the embodiment which has just been described,

  in particular by substituting equivalent technical means

  slow, without departing from the scope of the invention.

Claims (1)

CLAIMS 1 Pneumatic spring characterized in that it comprises a substantially cylindrical membrane (1), made of elastomeric material, which coats a resistant structure formed by a plurality of flexible and inextensible wires (2) arranged according to the generatrices of the cylindrical shape, however there is a plurality of rigid annular bodies (7) spaced from each other, coaxial with the membrane and arranged around it, said rigid annular bodies being in contact with the external surface of the membrane and the edges of the latter being fixed to the rigid annular bodies (7 ') furthest from each other. 2 pneumatic spring according to claim 1, characterized in that the rigid annular bodies are the turns of a helical rigid wire (7). 3 pneumatic spring according to claims 1 and 2, characterized in that the rigid annular bodies or the turns of the helicold in rigid wire are fixed to the outer surface of the membrane (1) 4 pneumatic spring according to any one of the claims 1 to 3, characterized in that the substantially cylindrical membrane (1) has corrugated walls so that the pitch of the corrugation is equal to the pitch of the turns of the helicold (7) or of the rigid annular bodies. Pneumatic spring according to Claims 1 and 3, characterized in that the turns of the helicold (7) or of the rigid annular bodies have a variable pitch. 6 air spring according to claims   1 and 2, characterized in that the assembly connecting the edges of the membrane (1) to the end turns (7 ') of the wire helicoid or to the rigid annular end bodies   includes a reversal of the edges (9) of the membrane if-   killed in this position around each turn (7 ') or rigid annular end body, and the fixing of the turned edge (9) of the membrane on the outer surface of this one.