FR2535796A1 - Fast pneumatic return device of a pneumatic-hydraulic assembly: force multiplying actuator - Google Patents

Abstract

Fast return device of a pneumatic-hydraulic assembly, with built-in force multiplier and direct force transmission, for the production of high kinetic energy by the piston effect. The invention relates to a volumetric power machine (actuator) requiring the use of two fluids for its operation and whose purpose is the production of high kinetic energy, with a fast pneumatic return cycle to the rest state of the system: the subject of the present invention. The fluids being: a. one the driver: compressed air - pressure varying from 2 to 12 bars - or any other compressible gas allowing the fast return of the moving pneumatic-hydraulic assembly; b. the other: hydraulic oil (integrated volume) for the force multiplication element.

Description

FAST PNEUMATIC RETURN DEVICE
OF A PNEUMO ~ HYDRAULIC ASSEMBLY: EFFORT MULTIPLIER CYLINDER
DESCRIPTION
The present invention relates to a volumetric power machine (cylinder), for developing, from two fluids, the compressed air of a traditional network, and the hydraulic oil in internal capacity, significant forces, greater than the forces of the cylinders. pneumatic, and in particular having a pneumatic rapid return cycle, of the element of the device developing the power.

It consists
- a steel cylinder with two compartments (2) and (3) respectively pneumatic and hydraulic,
- a mobile pneumatic piston (4), integral with a plunger (5): the piston rod.

 - a mobile hydraulic power piston (6) with pneumatic return, the hollow body (7) of which contains a hydraulic oil capacity.

 - a fixed annular diaphragm g8) limiting the displacement stroke of the pneumatic piston.

 - A series of seals (9) adapted to seal between the air, oil (2) and (3) compartments and the outside of the device.

- the diameter of the plunger (g-5) is less than the diameter of the hollow body (7) s capacity of the hydraulic piston (6),
- the compressed air enters through the supply orifice (Oa), develops a force, the result of which is the product of the air pressure (pressure unit le bar) by the surface of the pneumatic piTton (4) (surface unit: cm2), according to the mathematical formula:
E (force in daN) = P (pressure in bar) XS (surface in cm2).

 - the plunger (5) integral with the pneumatic piston (4) transmits the force generated by the latter, by its section, (therefore the surface of its rod), moves in the direction of the thrust (P) penetrates the body hollow (7) of the hydraulic piston (6), flushing out the oil which, rare 9th annular duct (resulting from the differences in diameter of the plunger (5) and the hollow body (7) is distributed over the rear face (10) of the hydraulic piston (6) - effort multiplication operation -, fills ive variable volume (11) if killed between the fixed diaphragm (8) and the mobile hydraulic piston (6), and moves the latter under the effect of the hydraulic oil boost.

 The resulting force is transmitted to the rod of the hydraulic piston (6).

 There is then displacement of the hydraulic piston and production of the calculated force.

 the rapid return of the assembly, hydraulic piston / pneumatic pedestrian, is carried out simultaneously by applying the air pressure from the network to the front faces (A) and (B) of the hydraulic and pneumatic pistons through the orifices (Ob).

the device according to the invention is particularly intended for mechanical power operations, requiring significant efforts from the compressed air used in industrial companies, and requiring reduced operating cycle times, in particular by the pneumatic return of the power element of the device which is the subject of the invention, for non-exhaustive operations such as
- punching
- marking
- bending
- crimping
# stamping
- fitting, etc.

significant forces, by piston effect, are traditionally obtained either
- With compressed air, this generates bulky devices, poor profitability, and expensive.

- with hydraulic oil, the dimensions are reduced. movements are generally slow, and it is necessary to use a power generator, such as for example a hydraulic power station, the assembly is expensive, and specific maintenance,
- or else a hydro-pneumatic combination, using the principle of multiplication as defined in our principle, but, in single acting function, with return of the device developing the power by spring, slow, not very mechanical, and very limited in stroke of power work.

 The device according to the invention overcomes these disadvantages. It has one effect; a pneumatic compartment whose piston transmits its power, via its rod - the plunger - to a hollow hydraulic piston of oil capacity, housed in a sealed hydraulic compartment of the preceding, and located at the front of this last.

 The assembly advances and produces an effort (in relation to the dimensions of the cylinder), under the pressure of the working fluid: compressed air, and the internal multiplication resulting from the second fluid: hydraulic oil.

 the return of the pneumo-hydraulic assembly is Pneumatic. Indeed, the pneumatic chambers (V). and (V ') are specifically intended for the return of the 1 piston / rod, hydraulic and pneumatic assemblies. No opposing mechanical element (such as a spring for example) intervening in the course of the operating cycle.

 The pneumatic chamber (V '') is the receiver of compressed air for the development of the power function.

 In the rapid pneumatic return function, the compressed air applied to the. reference faces (A) and (B) by a single conduit, allows the rapid return to the rear position of the hydraulic (6) and pneumatic (4) pistons.

Figure 1 shows in @ section a device according to the invention
ure 2 represents the operating principle of the device according to the invention.

 FIG. 3 represents the four main states of the operation of the device according to the invention.

The devices shown in Figures 1 and 2 include
- a steel body consisting of two parts (2) and (3), provided with pneumatic supply ports (Oa) (Ob); the dimensions of the assembly are relative to the powers developed.

- a mobile pneumatic piston (4), integral with its plunger finger rod (5)
- a movable hydraulic piston (6) comprising a hollow body (7) in sound: center longitudinally oriented to receive a cagacity of hydraulic oil.

 - a rear bottom (12) provided with a pneumatic supply orifice (Oa).

 different seals (9) ensuring 11 sealing between the pneumatic, hydraulic and atmosphere chambers.

As a nonlimiting example, we will describe the different execution phases and procedures for producing the prototypes which have been produced according to the invention.
A - MATERIALS
1 - mechanical components: the choice of materials for carrying out the invention is essential; in fact, given the significant efforts made, it is important to have recourse to ferrous metals, of stable and lasting mechanical strength,
with, therefore low transformation coefficients. Non-ferrous metals can be used; nevertheless, account must be taken of their mechanical and different characteristics from ferrous steels in order to keep the invention its defining definition criteria.

 2 - The sealing components: the seals.

 Classic in constitution and profile, they must be adapted to the operating pressures (engine air), as well as to the multiplication efforts of the system which is the subject of the invention.

B - THE DIFFERENT MECHANICAL ELEMENTS CONSTITUTING THE INVENTION.

 the body.

 I1 consists of two parts of identical or non-identical diameters, but concentric and connected together by a threaded part.

We will identify these two parts as respectively
1) the rear part: pneumatic Ref (2)
2) the front part: hydro-pheumatic Ref (3) 1) The rear pneumatic part Ref (2)
This mechanical part has a rear face (supply side Ref (Oa), as well as a front face (connection side to the hydraulic part) / It also consists of 2 types of machined parts
- fixed parts
- moving parts
a) production of fixed parts
The front face of the cylinder (2) serving as a machining reference, three concentric bores are made:
- the first crossing allows the passage of the pneumatic piston rod, or plunger (5)
- the second, with a larger diameter and a limited depth, serves as a housing for the seal (9) between the parts (2) and (3).

- the third, of a larger diameter than the second, concentric, but also of a limited depth, is tapped and receives the nut (@ ') for locking the seal reference below -; this nut is itself bored concentrically with the diameter of the plunger.
the outside diameter is reduced, threaded, to allow connection with the front part referenced (3).

 An annular groove (G) is factory on this threaded diameter; are connected to this annular groove, the different channels (C) communicating with a volumetric chamber (CV).

 A second annular groove (GAE), in line with the shoulder of the connecting thread, receives a seal.

 A third annular groove (GAE) having the same function as the previous one, is machined at the limit of the machining reference face.

 A threaded rear bottom (12) closes the cylinder by its ar rible face; in its center, a threaded opening (Oa) allows the installation of an external connection system.

 This connection cover has an annular groove receiving a seal.

 Its front face abuts the mobile pneumatic piston, a damping joint is housed in an annular groove.

the rear face of the cylinder (2) serving as a machining reference, two concentric bores are made
- the first bore of large diameter, of depth such that a web of material of several millimeters remains Before reaching the seal (9), it receives the mobile pneumatic piston (4).

 - the second bore, with a smaller diameter than the previous one, concentric and: a few millimeters deep, makes it possible to reveal a shoulder which will serve as a mechanical stop for the mobile pneumatic piston (4), on the one hand, and will delimit on the other hand a volumetric chamber (CV), the function of which is to ensure takeoff of the mobile pneumatic piston during its backward movement. The inlet of the working fluid is effected by several channels (C) of small diameter, which have their axes parallel to that of the cylinder (2), and, perpendicular to the latter, an annular groove (G), to which they attach .

b) production of moving parts
They are two in number (4) and (5), and are integral to form the mobile pneumatic piston. The piston (4): it is a metal disc generally of a different nature from the cylinder, and made of aluminum.

 3 on its annular part, three grooves are machined. to receive the seal, as well as a scraper seal.

In its axis, and concentric, two bores
- one allowing the passage of the plunger and its connection, receiving a seal in an annular groove,
- the other of larger diameter, allowing the housing of a fixing nut (QF) of the plunger must.

 The plunger (5): it is a smooth cylindrical axis at one end, shouldered and threaded at the other, and fixed by a nut (EP) and a lock washer, and put in place in the housing previously described and intended for this purpose.

2) n hydro-pneumatic front part Ref (3).

This mechanical part has:
- a rear face, connection side to the pneumatic front part.

 - a front face, allowing the passage of the rod of the mobile hydraulic power piston.

It also consists of two types of machined parts
a) fixed parts
b) moving parts
a) production of fixed parts
The rear face of the cylinder (3) serving as a machining reference, three concentric bores are produced
- the first through bore is made at the diameter of the tigo of the hydraulic power piston (6).

 - the second blind bore is made to the diameter of the hydraulic piston; its length is determined by the length of the hydraulic piston (6) added to the length of the desired displacement.

 - The third concentric bore delimits in the bottom of the preceding bore a volumetric chamber (CV '), the function of which is to ensure the pneumatic "take-off" of the hydraulic piston in its return function.

 - perpendicular to its axis, this chamber (CV ') receives several channels (C') of small diameters. These machining operations are carried out from the external diameter of the cylinder (3), and according to the different diameters of the latter.

 - each of the channels (C ') communicates, by two judiciously positioned machining operations, one annular (G "), internal, at the rear end of the cylinder (3), the other (C"), parallel to the axis of the cylinder (3), with the machined groove (G3 on the cylinder (2), and are in communication when the parts (2) and (3) are connected by their threaded parts.

 The front face of the cylinder (3) serving as a machining reference, two concentric bores, of diameter determining a shoulder, are produced to the dimensions of the mechanical guide also acting as a seal for the mobile hydraulic piston.

 The external front part of the cylinder is threaded, in order to allow the assembly assembly to be fixed, on a support external to the detailed system.

A screw (VR), called a filling screw, is positioned on
an external machining, and communicates with the hydraulic chamber (7) of the mobile hydro-pneumatic piston, when the latter is in the extreme front position
b) production of moving parts
A single movable and monobloc part in this assembly: the hollow hydro-pneumatic piston.

 It is a rod / piston assembly (6), made to the diameters of the bores described above, fitted with seals on the piston.

 The internal bore of the piston delimits a volume which will serve as an oil reservoir for the system described by the invention.

 This bore is concentric with the axis of the system. collected, but however this concentricity, by the very fact of the invention, is not mechanically necessary, and an approximate concentricity, in the range of 0.1 to 1.5 millimeters is acceptable.

Claims (4)

R @ VENDICATIONS  1 - D @@ positive power by pneumo-hydrau liquc integrated multiplication for the production of significant efforts from a network of compressed air varying between 6 and 12 bars, characterized by the fat that it includes a pneumatic return rapid assembly of the hydraulic piston (6) and the pneumatic piston (4).  2 - Device according to claim 1 -, characterized by the fact of a common compressed air, which is distributed on the pneumatic and hydraulic pistons for the return function of the assembly.  3 - Device according to claims 1 - and 2 -, characterized in that in the absence of return spring or any other mechanical system, the rapid return is effected by the expansion of a compressible fluid such as air or any other gas having oo understanding and relaxing qualities.  K Device according to claims 1 - 2 - and 3 -, oaractérisé by the fact of a rapid return by pnrt the use of compressible gas and allowing to increase the efforts of ascent. of the power system of the device by increasing the pneumatic support face of the hydraulic piston (6).  5 - Device according to any one of the preceding claims, characterized in that the do: gt plunger has a smaller diameter (and preferably from 1 to 2 millimeters) than that of the oil tank integrated in the power piston.  6 - Device according to any one of the preceding claims, aaractérisé by the fact of an approximate concentricity of the two parts of the assembly consisting of the compartments (2) pneumatic and (3) hydraulic, and in particular by the concentricity of the plunger (5) and the hydraulic oil tank (7) of the hydraulic piston (6); this approximate concentricity can have deviations varying from 0.1 to 1.5 millimeters.