EP3787823A1

EP3787823A1 - Bar feeder

Info

Publication number: EP3787823A1
Application number: EP19726173.8A
Authority: EP
Inventors: Franco TRANQUILLI
Original assignee: Metal Art di Franco e Mauro Tranquilli SRL
Current assignee: Metal Art di Franco e Mauro Tranquilli SRL
Priority date: 2018-05-04
Filing date: 2019-05-02
Publication date: 2021-03-10
Also published as: EA039712B1; IT201800005069A1; WO2019211883A1; EA202092626A1

Abstract

Feeding apparatus for feeding elongate semi-finished products (2) along a feeding line (4) to a machine tool. The feeding apparatus comprises an elongate rod-shaped body (6) which can be positioned along the feeding line (4) and a tubular body (8) which can be positioned on the feeding line (4), the rod-shaped body (6) being supported by a first carriage (7) and the tubular body (8) being supported by a second carriage (10), with said first and second carriages (7,10) being motor-driven, movable back and forth parallel to the feeding line (4). The feeding apparatus further comprises control means (11) coordinating the movements of the carriages (7,10), thus allowing a semi-finished product (2) interposed between the rod-shaped body (6) and the tubular body (8) to penetrate the tubular body (8) and to be guided along it along the feed line (4) due to the longitudinal action applied by the rod-shaped body (6). The first carriage (7) additionally comprises a motor-driven slide (17), translatable in a guide (19) in both directions along an axis (18) transversal to the feeding line (4), which supports the rod-shaped body (6) between a first end-of-stroke position wherein said rod- shaped body (6) is aligned with the feeding line (4), as the operating position, and a second end-of-stroke position wherein said rod-shaped body (6) is offset from the feeding line (4), as the non-operating position.

Description

BAR FEEDER

Technical Field

The present invention relates to servo-mechanisms for a machine tool, in particular a lathe, and concerns a feeding apparatus for feeding elongate semi-finished products, such as metal bars or rods.

Background art

As it is known, bar-shaped semi-finished products for machining are fed into a lathe-type machine tool through a tubular conveyor of fixed and invariable size, which is housed in the structure of the machine tool itself. Bar-shaped semi-finished products can come in various diameters depending on the needs of the machining in question, with the sole limitation being the maximum diameter, which is determined by the diameter of the machine tool conveyor through which the semi-finished products are to travel.

When the machine tool is in use, one end of the bar shaped semi-finished products is always supported by the spindle of the machine tool, whereas the rest of the bar is supported by supports outside the conveyor or by special collets that are inserted into the conveyor accordingly.

In general, given the distance between the supports and the spindle, and given the difference in dimensions between the diameter of the conveyor and the diameter of the bar-shaped semi-finished product, the intermediate section of the semi-finished product vis-a-vis the supports, which may also be contained within the conveyor where appropriate, tends to inflect to a greater or lesser extent.

Consequently, the centre of gravity of the bar-shaped semi-finished product shifts away from the geometric axis of the bar by a certain distance, or shifts away from the axis of the conveyor and of the machine tool spindle, which are aligned to the abovementioned geometric axis.

Due to the rotary motion of the bar, caused by its rotation together with the machine tool spindle, this mass eccentricity - even if moderate - driven by the inertial forces, tends to increase the deflection of elastic deformation inherent in static bending, as well as triggering mechanical vibrations which, on the one hand, impact negatively on machining quality and, on the other hand, are responsible for generating environmental noise which causes considerable discomfort to personnel involved in machining, who are exposed to the noise for the duration of machining work.

These drawbacks are all the more accentuated the greater the difference in dimensions is between the machine tool conveyor and the bar-shaped semi-finished product for machining .

To limit the impact of these drawbacks, measures must be adopted geared towards keeping the geometrical axis of the bar-shaped semi-finished product as aligned as possible to the conveyor axis - that is to say, with the geometric axis of the machine tool spindle. In the first type of feeder apparatuses according to the prior art, the bar is normally fed toward the machine tool in a guide along a channel, or rather a substantially continuous cradle with a semi-circular cross-section, with this channel aligned with the conveyor in such a way as to align and keep the geometric axis of the semi finished product aligned with the axis of the spindle. Any variation in the diameter of the bar-shaped semi finished product when in use, as compared to the cross- sectional diameter of the semi-circular cradle will inevitably lead to conditions whereby the abovementioned drawbacks will arise. This means that the cradle should be replaced whenever its dimensions differ from those of the specific bar-shaped semi-finished product to be inserted. However, since its replacement entails downtime and not-inconsiderable preparatory work, the prior art displays a tendency for using the same cradle for semi-finished products of varying diameters, thus accepting that there will be a certain margin of error; the higher the quality of machining required and the lower the tolerable environmental noise impact, the lower the margin of error must be.

When the difference in diameter exceeds the range of admissible diameters, a common resort is to physically replace the guide channels by releasing them from their fastening parts, disassembling them from the loader and then assembling channels in their place with diameters congruent to those of the bars to be machined. A similar situation, and similar solutions, apply to the special rod-shaped pushers mounted on the feeding apparatuses, which are designed to push bar-shaped semi-finished products along the feed line, as these pushers must also be geometrically aligned with the rotation axis of the spindle .

The channel-replacement process - normally carried out in modular form, with segments placed successively to one another and bolted to the apparatus structure - is laborious, time-consuming and requires the machine tool to be stopped, thus negatively impacting on machining costs .

Replacement operations are not limited to changing the bar guide channels, but also involve the pushers being replaced, as mentioned above. The disassembly and reassembly of operating parts of the loader may be further exacerbated by other actions that may be carried out to remove and reinstall the safety accident prevention devices that are are normally mounted on these machine tools.

Ultimately, such prior-art feeding systems are optimised to serve a narrow range of bar sizes and are practically incapable of being adjusted to machine semi-finished products that have somewhat different diameters from those for which originally intended. The aim of the present invention is therefore to resolve the abovementioned technical issues.

Disclosure of the Invention

The technical purpose of the present invention is therefore to provide a solution to the issues arising in the prior art by proposing a feeding apparatus designed to be precisely configurable for each specific diameter of elongate semi-finished product to be machined and to be configurable in this way for all commercial diameters of bar-shaped semi-finished products that may be contained within a tubular conveyor of a machine tool up to a maximum pre-established diameter, without having to disassemble and reassemble mechanical connecting parts of any kind.

According to the invention, such results are achieved by a feeding apparatus as defined in the accompanying claims .

Brief Description of Drawings

The technical characteristics and other advantages of the invention are made clear from the description below with reference to an exemplary embodiment illustrated in the accompanying drawings, wherein:

- Figure 1 is a perspective overall view of a feeding apparatus for feeding bar-shaped semi-finished products according to the invention;

- Figure 2 is an enlarged, partial view of Figure 1, showing certain details of the feeding apparatus;

- Figure 3 is a perspective view showing the details in Figure 2, as observed from a different point of view so as to better highlight some details that are not otherwise visible;

- Figure 4 is a top plan view of Figure 1, stripped of some details so as to better highlight others;

- Figure 5 is a rear view of the invention in Figure 1;

- Figure 6 is a top view of the invention shown in Figure 1, stripped of some details so as to better highlight other hidden details;

- Figure 7 shows a rear view of the invention according to its first operational setup;

- Figure 8 shows another rear view of the invention shown in Figure 7 according to its second operational setup;

Detailed description of preferred embodiment of the invention

Referring now to the figures contained in the accompanying drawings, Figure 1 shows, with reference number 1, a complete feeding apparatus for feeding elongate semi-finished products (2) into a tubular conveyor (3) of a machine tool, in particular a lathe, which is not shown in the drawings.

The apparatus (1) essentially comprises a feeding line (4), preferably horizontal, along which the semi finished products (2) are fed, above at least one supporting cradle (5), longitudinally to themselves, and until they pass through said conveyor (3); an elongate rod-shaped body (6) positioned longitudinally to the feeding line (4), which (as highlighted in Figures 2 and 3) is supported by a first carriage (7), which is motor- driven and movable back and forth and parallel to said feeding line (4), travelling along parallel guiding rails, as shown with reference number (32) .

The apparatus (1) further comprises a tubular body (8) positioned on the feeding line (4), having an inner axial through cavity (9) substantially shaped to match the shape of the rod-shaped body (6) . The body (8) is supported by a second carriage (10), which is motor- driven, movable back and forth parallel to the feeding line (4) and is also able to travel along the tracks (32), as clearly shown in Figure 4.

The carriages (7 and 10) are motor-driven independently of one another, moving towards or away from one another so as to enable the bar-shaped semi-finished products (2) to be inserted into the cradle (5) in an intermediate position vis-a-vis the rod-shaped body (6) and the tubular body (8), as can be seen in Figure 4. The carriages (7) and (10) are moved by their respective conveyors (33,34), which are separate from and parallel to one another and which have metal bands forming a closed loop around a pulley wheel couple (35,36), at least one of which is motor-driven.

The apparatus (1) also comprises control means (11) as illustrated in Figure 1, which, by coordinating the motor synchronisation of the movements of said first and second carriages (7,10) along the feeding line (4) where appropriate, allow a said semi-finished product, (2) interposed between said rod-shaped body (6) and said tubular body (8), to penetrate said tubular body (8), to travel along it longitudinally towards the machine tool conveyor (3) , and to pass - at least in one direction through said conveyor (3) - due to the longitudinal action applied to said semi-finished product (2) .

It should be noted that, since the tubular body (8) can also operate inside the machine tool conveyor (3), said tubular body (8) is able to provide a continuous support for the semi-finished product (2) inside the conveyor

(3) . Such a characteristic, which is generally advantageous, is particularly important and useful when semi-finished products (2) are very small in diameter, such as when manufacturing small-diameter screws.

The apparatus (1) also comprises supporting and guiding means (13) for said semi-finished product (2) along said feeding line (4) .

It can be seen in Figure 6 that the supporting and guiding means (13) preferably comprise a plurality of freely rotatable revolving bodies (14), which are positioned longitudinally to the feeding line (4), with these revolving bodies (14) preferably including a plurality of double truncated cone rollers (15) with axes (16) of rotation transversal to the feeding line

(4), which in combination with each other clamp a said semi-finished product (2) interposed between them, which is oriented longitudinally to the feeding line (4) and which is freely translatable in a guide and aligned with the spindle of the machine longitudinally to themselves. More particularly, from comparing Figures 7 and 8 it can be seen that the double truncated cone rollers (15) can be moved away from or toward the feeding line (4) to facilitate the introduction of elongate semi-finished products (2) from the suitable loading means, which are not shown in the drawings, onto the feeding line (4) .

It can also be noted from Figure 7 and 8 that said first carriage (7) also comprises a motor-driven slide (17), translatable in a guide (19) in both vertical directions along an axis (18) transversal to the feeding line (4), with the slide (17) supporting said rod-shaped body (6) . The free translation of the slide (17) allows the pushing body (6) to be raised away from and lowered towards the cradle (5) vertically to the feeding line (4) - envisaged to pass through the geometrical centre of the tubular body (2) - between two end-of-stroke positions, in a first, operating position, of which said rod-shaped body (6) is aligned along the feeding line (4), and in the second of which it is offset and moved away from the feeding line in a non-operating condition.

The said guide (19) is preferably open at its top end for allowing rapid disengagement and subsequent engagement of said rod-shaped body (6) . The above, simply by allowing the tubular body (8) to be similarly translatable in a parallel and vertical manner (through the linear actuators marked (37)), explains why the apparatus (1) allows the quick and manual replacement of the rod-shaped body (6), the tubular body (8) or both of these components without having to disassemble and subsequently reassemble them, thus ensuring that semi finished products (2) of any diameter are always perfectly centred and aligned with the machine tool spindle .

It is clear from the foregoing that the apparatus (1) can be reconfigured in relation to changes to machining needs without any disassembly and reassembly of fastening components, such as bolts, pins, tabs and so on. The invention entirely fulfils its stated purposes as well as offering the added advantage of shortening the time required for loading bars onto the feeding line (4) and moving elements (2) quickly along the feeding line ( 4 ) .

Claims

1. A feeding apparatus for feeding semi-finished products (2) which have an elongate shape along a feeding line (4) of a machine tool, comprising an elongate rod shaped body (6) positioned longitudinally to the feeding line (4), supported by a motor-driven first carriage (7); a tubular body (8) positioned on the feeding line (4) , supported by a second carriage (10) , with said first and second carriages (7,8) being motor-driven, movable back and forth parallel to the feeding line (4); control means (11) , which coordinate the motor synchronisation of the movements of said first and second carriages (7,10) along the feeding line (4), allowing a said semi finished product (2) interposed between said rod-shaped body (6) and said tubular body (8) to penetrate said tubular body (8) and to travel along it longitudinally, guided along the line (4) due to the longitudinal action applied to said semi-finished product (2) by said rod shaped body (6); an apparatus (1) wherein said first carriage (7) comprises a motor-driven slide (17), translatable in a guide (19) in both directions along an axis (18) transversal to the feeding line (4), which supports said rod-shaped body (6) between end of stroke positions, in a first, operating position, of which said rod-shaped body (6) is aligned along the feeding line (4), and in the second of which it is offset from the feeding line in a non-operating condition.

2. The apparatus according claim 1, characterised in that said guide (19) is open at one end for allowing rapid disengagement and subsequent engagement at least of said rod-shaped body (6) .

3. The apparatus according to claim 1, characterised in that it comprises supporting and guiding means (13) for said semi-finished product (2) along said feeding line (4) which comprise a plurality of freely rotatable revolving bodies (14), which are positioned longitudinally to the feeding line (4) .

4. The apparatus according claim 3, characterised in that said revolving bodies (14) comprise a plurality of double truncated cone rollers (15) with axes (16) of rotation transversal to the feeding line (4), which in combination with each other clamp a said semi-finished product (2) interposed between them, which is oriented longitudinally to the feeding line (4) .

5. The apparatus according claim 4, characterised in that said double truncated cone rollers (15) are movable towards and away from the feeding line (4) to facilitate the introduction of semi-finished products (2) which have an elongate shape into the feeding line (4) .