EP2274117B1 - Supply station - Google Patents

Abstract

The invention relates to a wire feed station of a wire shaping machine, said station including grooved rollers functioning in pairs and rotating in reverse directions with respect to each other. The wire is clamped between said rollers by these moving closer to one another. Both rollers of the same pair of driving rollers are supported at the front of the same bearing block unit, said bearing block being elastically deformable to absorb a relative movement of the rollers. Preferably, said bearing block also supports an endless transmission screw on which are engaged a couple of transmission wheels coaxial with the driving rollers which they drive into rotation. More particularly, a bearing block is deformed so that a relative movement of the rollers results in a rotation-deformation of the bearing block about the transmission screw axis.

Description

• montage où les arbres supportant les galets sont montés dans deux paliers, avec un palier arrière d'au moins un des arbres qui doit être rotulant ce qui génère, lors du rapprochement des galets un effet de ciseaux par désalignement des gorges périphériques annulaires des galets entre lesquelles défile le fil. Ce défaut tend à faire tourner le fil sur son axe de défilement au cours de l'avance du fil et génère des dispersions entre les pièces fabriquées en aval sur le poste de façonnage. Un montage de ce type est montré à titre d'exemple sur la figure 1a annexée un dispositif d'amenage où l'arbre (a) du galet supérieur non représenté est monté sur un palier rotulant c'est-à-dire monté sur un roulement à rotule (b) et actionné par un actionneur pneumatique (c).
• montage où les arbres qui supportent les galets sont chacun monté dans un palier unique, et où leur déplacement relatif fait intervenir des moyens de guidage tels que par exemples des colonnes, des guidages à patins ou autres. Dans ce type de montage le moindre jeu dans lesdits moyens de guidage (par exemple jeu de montage et/ou jeu d'usure) génère des défauts d'alignement des gorges périphériques des galets et génère donc les mêmes défauts qu'avec le montage précédent. Un montage de ce type est montré à titre d'exemple sur les figures 2a et 2b où le fil (d) est pincé entre deux paires de galets (e, f). Deux galets (e, f) d'une même paire sont montés sur un palier unique avec deux roulements de guidage (g, h) dans une même pièce, le moyen de guidage étant un guidage à colonne (i).

Pour les deux types de montage précités, le nombre de pièces nécessaires au guidage des arbres est important ce qui implique une chaîne de cotes longues et une précision finale de guidage médiocre qui n'est pas satisfaisante compte tenu de répétabilité des pièces à façonner.The invention relates to a device for feeding wire in a machine for shaping wire (see document DE-A-195 42 895 on which the preamble of claim 1) is based.
Such a machine, numerically controlled on a wire (or a bar) metal various shaping operations such as for example bending, folding, etc ... made by different posts mounted on a frame.
The term wire is a generic term used in the profession and encompasses both a wire itself as a bar or a tube.
One of the stations is the wire feed station whose function is to feed horizontally said wire along a running axis, to the tools of a forming station.
The wire is moved by the feeding station by means of grooved rollers operating in pairs and rotating in opposite directions from one another, generally the rollers are placed one above the other with a lower roller fixed and an upper roller movable vertically in one direction and the other.
The wire is clamped between the two rollers by relative approximation thereof and it is placed in the annular grooves of said rollers.
The movable roller is actuated by an actuator which defines the clamping force on the wire and which can be a screw, a pneumatic or hydraulic cylinder, an eccentric mechanism or other.
The number of pairs of rolls varies depending on the diameter of the wire and / or the shaping operations to be performed on it.
Two possible assemblies of the rollers of the same pair of rollers are observed, namely:

• mounting where the shafts supporting the rollers are mounted in two bearings, with a rear bearing of at least one of the shafts which is to be swiveling which generates, when bringing the rollers together a scissors effect by misalignment of the annular peripheral grooves of the rollers between which scrolls the thread. This defect tends to rotate the wire on its axis of travel during the advance of the wire and generates dispersions between the parts manufactured downstream on the forming station. An assembly of this type is shown by way of example on the figure 1a attached a feeding device where the shaft (a) of the upper roller not shown is mounted on a swivel bearing that is to say mounted on a ball bearing (b) and actuated by a pneumatic actuator (c).
• assembly where the shafts that support the rollers are each mounted in a single bearing, and where their relative movement involves guide means such as for example columns, slide guides or others. In this type of assembly the slightest play in said guide means (for example mounting clearance and / or wear clearance) generates misalignment of the peripheral grooves of the rollers and thus generates the same defects as with the previous assembly. . An assembly of this type is shown by way of example on Figures 2a and 2b where the wire (d) is pinched between two pairs of rollers (e, f). Two rollers (e, f) of the same pair are mounted on a single bearing with two guide bearings (g, h) in one piece, the guide means being a column guide (i).

For the two types of assembly mentioned above, the number of parts needed to guide the shafts is important, which implies a long chain of dimensions and a poor final guide accuracy which is not satisfactory given the repeatability of the workpieces.

The object of the invention is to solve the problems of feeding devices of the prior art by limiting the number of parts and limiting the deflections generating the chisel effect.
This object is achieved by a wire feeding station in a wire forming machine, said station having grooved rollers operating in pairs and rotating in opposite directions from one another, the wire being pinched between said rollers by relative approximation thereof, characterized in that the two rollers of the same pair of drive rollers are carried forward of the same unit bearing block, said bearing block being elastically deformable for absorb a relative displacement of the rollers. Preferably, said bearing block also carries an endless transmission screw on which a pair of transmission wheels coaxial with the driving rollers which they drive in rotation mesh with.
More particularly, a bearing block deforms so that a relative displacement of the rollers results in a rotation-deformation of the bearing block around the axis of the transmission screw.

• figure 1a : vue en coupe verticale d'un dispositif d'amenage de l'art antérieur à arbre rotulant,
• figures 2a, 2b : coupe verticale de face et coupe verticale transversale, d'un dispositif d'amenage de l'art antérieur à palier unique,
• figures 3 et 4 : vues générales arrière et avant d'un dispositif selon l'invention à trois blocs-paliers de doubles galets,
• figure 5 : coupe verticale selon le plan de défilement,
• figure 6 : vue de dessus,
• figure 7 : coupe verticale selon AA de la figure 6,
• figure 8 : coupe verticale selon BB de la figure 6.

The invention will be better understood from the following description given with reference to the following appended figures:

• figure 1a : vertical sectional view of a feeding device of the prior art rotary shaft,
• Figures 2a, 2b vertical vertical section and transverse vertical section, a prior art single-tier feeding device,
• Figures 3 and 4 : general rear and front views of a device according to the invention with three bearing blocks of double rollers,
• figure 5 : vertical section according to the scrolling plane,
• figure 6 : top view,
• figure 7 : vertical section according to AA of the figure 6 ,
• figure 8 : vertical section according to BB of the figure 6 .

A machine according to the invention is partially represented on the Figures 5 to 8 which is an example of non-limiting implementation.
It comprises a feeding station (1) which guides a wire (2) in a horizontal axis of travel (3) successively through a straightener (5) and a guide gun (4) before entering the position of then fed to a forming station (6) not shown in detail.
The feed station (1) shown comprises three unit bearing blocks such that (7) (this number is not limiting) secured to each other by tie rods (8).

We now describe a unitary bearing unit (7) according to the invention. It comprises a roller with lower groove (10) and a roller with upper groove (9) placed vertically one above the other, their peripheral guide grooves being in the same plane (P) called vertical guide plane.
The rollers (9, 10) are carried and guided respectively by an upper bearing (11) and an upper bearing (12) carried on the front of the bearing block and are rotated by an upper transmission wheel (13) and a lower transmission wheel (14) which meshes with an endless transmission screw (15) driven in rotation by a motor not visible in the figures and placed at the end of the transmission screw in a cowling (16).
The worm (15) is carried by two lateral bearings (17) which maintain its horizontal axis of rotation (18), fixed parallel to the axis of travel (3) of the wire and behind it.
It is noted that on the one hand the upper wheel (13) and the upper bearing (11) are mounted on a common axis (19), on the other hand, the lower wheel (14) and the lower bearing (12) are mounted on a common axis (20) and that the conformation of the unit bearing block (7) allows a relative movement of the two axes (19) and (20).
This relative displacement is generated by the fact that the bearing block is deformable thanks to a horizontal plane slot (21) opening on the front of the block and limited to the rear by a circular hole (22) opening laterally on the side and side. other of the block (see figures 4 and 8 ).

The bearing block deforms when compressing the rollers (9, 10) by a compression means to create flexion-rotation about the axis of rotation of the worm (18).

Firstly, the means for producing flexion-rotation is described.
The circular hole (22) is parallel to the axis (18) of a bore (19) of the bearing block and in which the worm (15) rotates, and at a distance therefrom which is calculated from in order to provide a wall thickness (23) towards the front of the bore (19) equivalent to the wall thickness (24) towards the rear of the bore (19).
The dimension of this wall thickness (23) or (24) is calculated by the manufacturer according to the elasticity parameter of the material in which the bearing block is produced and according to the diameter of the bore (19).

By way of non-limiting example for an aluminum bearing block and a bore of diameter 44 mm ± 0.2, a thickness (23) or (24) of 6 mm ± 0.1 is provided.

We now describe a roller compression means.
A horizontal bar (25) provided on the top of the bearing block is carried by two vertical bars (26) made of steel. A tensioning screw (27) placed between the spreader and a shoulder (28) of the bearing block (7) can raise or lower the spreader (25).
The bars (26) shaped straps at their upper end, serve as a spring and ensure the force exerted by the rollers on the wire (2).
The bearing block further comprises an indexing means (29) for applying a predetermined clamping force. This means (29) is for example a toothed wheel blocked by a stepped foot (30) mounted on a spring. Unlocking the foot can turn the knob and lock it again in another predetermined position.
By acting on the tensioning screw (27) it is possible to move the upper roller (9) away from or closer to the lower roller (10) without modifying the gearing of the upper (13) and lower (14) wheels on the drive screw ( 15).
The clamping amplitude of the rollers is limited by construction to the minimum required to release or clamp the wire within its dimensional tolerance range.
With the numerical values given above by way of non-limiting example, the clamping amplitude is measured in the plane (P) is 0.25 mm on either side of the axis of movement (3). a total amplitude of the order of 0.5 mm.

Compared to the prior art, the means for moving the rollers are removed and replaced by an elastic deformation of a single bearing block carrying the shafts of the two rollers, and absorbing the displacement of the rollers by elastic deformation of said bearing block.
The deformation is calculated to result in a rotation around the axis of the drive screw which on the one hand does not modify the backlash and therefore the gearing of the transmission, and secondly reduces the chain of dimension between the two trees since it comes down to the distance between said trees.
This conformation makes it possible to be as compact as possible in terms of the size of the bearings required with regard to the forces and the level of the gear teeth and thus makes it possible to reduce as much as possible the inertia of the entire drive chain and therefore a possible increase of the dynamics.
This compact configuration allows a reduction in the number of parts and an increase in the positioning accuracy of the rollers with a reduced dimension chain.

This configuration is also modular because it allows to couple several bearing blocks (7) together according to the specifications of the work to be done and / or the wire to be shaped. By way of nonlimiting example, the figures show three bearing blocks coupled together by conventional coupling means for those skilled in the art to form a feeding station which is then fixed on the frame of the forming machine.

Claims (7)

1. Feed station (1) of a wire (2) for a wire shaping machine, said station comprising grooved rollers functioning in pairs and rotating in reverse in relation to one another, with the wire being clamped between said rollers by these moving closer to one another, characterised in that both rollers of the same pair of driving rollers (9, 10) are supported at the front of the same bearing block unit (7), said bearing block being elastically deformable to absorb a relative displacement of the rollers (9, 10).
2. Feed station according to claim 1, characterised in that said bearing block (7) also supports an endless transmission screw (15) onto which a couple of transmission wheels (13, 14) are engaged which are coaxial with the driving rollers (9, 10) which they drive in rotation.
3. Feed station according to claim 2, characterised in that a bearing block (7) is deformed such that a relative displacement of the rollers is translated by a rotational deformation of the bearing block about the transmission screw axis (15).
4. Feed station according to claim 3, characterised in that a bearing block comprises a horizontal planar slot (21) opening into the front of the block and delimited to the rear by a circular hole (22) opening laterally into either side of the bearing block.
5. Feed station according to any one of claims 1 to 4, characterised in that it further comprises a roller compression means.
6. Feed station according to claim 5, characterised in that the roller compression means is formed by a spreader beam (25) supported by bars (26) and moved by a tensioning screw (27).
7. Feed station according to any one of claims 1 to 6, characterised in that it comprises several bearing block units coupled together.

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