WO2011089498A1

WO2011089498A1 - Ejection device for a threading machine

Info

Publication number: WO2011089498A1
Application number: PCT/IB2011/000057
Authority: WO
Inventors: Sebastiano Raco
Original assignee: A. Agrati S.P.A.
Priority date: 2010-01-19
Filing date: 2011-01-14
Publication date: 2011-07-28
Also published as: EP2525927A1; ITMI20100008U1; ITMO20100284A1; CN102695570A; IT1402582B1; EP2525927B1

Abstract

An ejection device (1) suitable for ejecting a screw (3) after being threaded by a threading machine (2), com- prising: Supporting means (7) suitable for being assembled on said threading machine (2); ejecting means (13) supported by said supporting means (7) and suitable for coming into contact with said screw (3); return means (24) cooperating with said ejecting means (13); said ejecting means (13) being movable between a with¬ drawn position (R) with respect to said supporting means (7), towards which said ejecting means (13) are pushed by said screw (3) due to the movement impressed by said threading machine (2) so as to oppose and mechanically load said return means (24), and an extended position (P) at least partially with respect to said supporting means (7), towards which said ejecting means (13) are propelled by said return means (24) so as to expel said screw (3) from said threading machine (2).

Description

EJECTION DEVICE FOR A THREADING MACHINE

The invention relates to an ejection device, in par- ticular suitable for being assembled on machine tools, such as machines for the forming of objects, in particular machines for threading screws or similar items.

A forming machine for threading screws comprising a fixed comb, and a movable comb suitable for the resting of a screw to be threaded and configured for moving in relation to and parallel to the fixed comb, is known. The surfaces of the movable and fixed comb, destined for coming into contact with the screw, are suitably shaped so as to obtain the desired threading on the latter.

During its functioning, the movable comb moves maintaining a pre-fixed distance from the fixed comb, it entrains the screw with it, forcing it to roll onto the fixed comb, and exerts a forming pressure on the same which is such as to generate the desired threading. Gen- erally a liquid is also sprayed, such as oil, for lubricating and cooling the screw under processing.

Once the movable comb has reached its run-end, the screw, already threaded, is substantially only in contact with the movable comb, and no longer with the fixed comb. At this point, the threaded screw must be removed from the combs. For this purpose, a compressed-air ejection device intervenes, which supplies a continuous blast of pressurized air directed against the screw in order to remove it from the machine.

A known defect of the ejection device is the high energy consumption due to the operations necessary for obtain, managing and using the compressed air, which implies high costs.

In addition, the above ejection system is relatively noisy and therefore creates high sound pollution which is particularly harmful for the operators present in the vicinity of the forming machine.

The above defects are worsened by the fact that the compressed air is supplied continuously, not only when necessary.

A further defect of the above ejection device is that the jet of compressed air, when striking the cooling oil and lubricant present around the screw, causes oil splashes everywhere, unacceptably staining the operating area around the machine.

A further defect is that the ejection device is not capable of reliably removing the threaded screw from the threading machine. In other words, the jet of compressed air may not be sufficient for ejecting the screw and this can lead to undesired blockages of the machine which, in addition to producing serious damage to the machine itself, can cause accidents which are dangerous for the operators in the area close to the machine. Furthermore, there are long stoppages of the machine for allowing the repristination or repair of the same machine, with consequent losses in the production cycles.

One of the objectives of the invention is to improve the known devices for the ejection of screws from the combs of a threading machine.

A further objective of the invention is to provide an ejection device which is extremely economical and simple to construct and equally effective.

Another objective of the invention is to provide an ejection device capable of greatly reducing the costs for the production of threaded screws, and considerably improving the environmental operating conditions, in particular with respect to cleanness, and noise around the threading machines on which it is assembled.

For a better understanding of the invention and for its embodiment, reference should be made to the enclosed drawings which provide some illustrative and non-limiting embodiment examples, in which:

Figure 1 is a longitudinal schematic view showing an ejection device according to the invention, and a part of a threading machine on which said device is assembled in a first operative position;

Figure 2 is a view of the threading machine and ejection device in a second operative position;

Figure 3 is a view of the threading machine and ejec- tion device in a third operative position;

Figure 4 shows a first version of the ejection device according to the invention;

Figure 5 shows a second version of the ejection device according to the invention.

With reference to figures 1 to 5, these show an ejection device 1, which can be used in the field of screw production, in particular applicable to various threading machines. The threading machines to which reference is made comprise so-called "combined progressive" forming machines which, by means of a cold forming process, generate a desired threading on said screws. The present ejection device 1, once assembled on a threading machine 2, allows the screws to be automatically evacuated, once the respective threading has been obtained on the same. In the following description, particular reference is made to a processing process which comprises generating the threading on each screw 3 with the use of suitable tool-elements known as "threading combs" included in the threading machine 2. The threading combs comprise suita- bly shaped threading surfaces which, when put in contact with high pressure against the screw 3, imprint the de^¬ sired threading on the latter.

As schematically shown in Figures 1 to 3, the thread^¬ ing machine 2 comprises a fixed comb element 4, arranged in a stationary position, and a movable comb 5 configured so as to move in relation to the fixed comb 4 along an operative direction O. The fixed comb 4 and the movable comb 5 reciprocally extend parallel and at a certain distance from each other to allow the interpositioning of the screw 3 on which the threading is to be obtained. An operating area 10 is defined between the fixed comb 4 and movable comb 5, in which the screw 3 advances while it is being processed.

In particular, the screw 3 is positioned with one of its longitudinal axes L arranged transversally, in particular substantially orthogonally, to the operative direction 0.

The ejection device 1 according to the invention, as shown in Figure 1, is connected on the threading machine 2, in particular close to a first area of the end 6 of the movable comb 5.

The ejection device 1 comprises a supporting body 7, configured to be assembled on the threading machine 2, by means of suitable fixing means such as screws which are received in respective fixing openings or holes 8. The supporting body 7 can have any form adaptable to the par^¬ ticular geometry of the portion of the threading machine 2 on which it is assembled. In this respect, the form and/or number and/or position and/or dimension of the fixing openings 8 are suitably selected to adapt to the particular threading machine 2. Figures 4 and 5 show two different versions of the supporting body 7, which differ in the geometry but exert the same function.

The supporting body 7 comprises a connecting surface 11 which is adhered to a suitable reception area of the threading machine 2.

The ejection device 1 comprises an ejecting element 13 suitable for coming into contact with the screw 3 and ejecting it once it has been threaded. In particular, a contact end 15 is defined on the ejecting element 13, in particular rounded, or, in any case suitably shaped for effectively interacting with the screw 3 without damaging the latter.

The ejecting element is situated near an upper surface 9 of the supporting body 7, the upper surface 9 being positioned on the opposite side with respect to the connection surface 11, therefore destined for facing the operating area 10.

The ejecting element 13 is movable with respect to the supporting body 7. In particular, the ejecting element 13 can move parallelly to the operative direction 0. In par^¬ ticular, the ejecting element 13 can move between an extended position P (shown in Figures 1, 2, 4 and 5) where it is at least partially projected with respect to the supporting body 7, towards an end 14 of the movable comb 5 opposite to the first area of the end 6, and a withdrawn position R (shown in Figure 3) where it is at least partially withdrawn with respect to the supporting body 7. In particular, in the withdrawn position R, the eject- ing element 13 is closer to a central area of the upper surface 9 of the supporting body 7.

The ejecting element 13 shown in the enclosed figures has an oblong shape having a longitudinal axis X, in particular it is bar- or pivot-shaped. The ejecting element 13 can have a different shape, however, for example it can be in the form of a plate or it can have any desired form provided it is suitable for exerting its function.

The ejecting element 13 is movably connected to the supporting body 7, in particular but not necessarily, by means of a pair of bracket elements 12 shaped so as to be fixed on the upper surface 9. The shape and/or number and/or position and/or dimension of each of the bracket elements 12 can be suitably selected according to the geometry or structure of the threading machine 2, and therefore according to the form of the supporting body 7. Figures 4 and 5 show two different versions of bracket elements 12, which differ in the geometry but exert the same function of slidingly supporting the ejecting element 13 with respect to the supporting body 7.

The bracket elements 12 comprise a first bracket element 12a, closer to the contact end 15, and a second bracket element 12b positioned at a suitable distance from the first bracket element 12a. The first bracket element 12a and the second bracket element 12b, in par- ticular but not exclusively, extend parallel to each other .

In the version of Figure 4, each bracket element 12 comprises a first elongated portion 16, arranged substantially orthogonally to the longitudinal axis X and ex- tending parallel to the upper surface 9. Each bracket element 12 comprises a first plate portion 17 which projects transversally from the first elongated portion 16. The first plate portions 17 are shaped so that they can be substantially flanked next to each other, so as to correctly define the distance between the first elongated portions 16, in order to obtain a precise and correct assembly and functioning of the ejecting element 13. Housing openings 20 are situated on the bracket elements 12, inside which the ejecting element 13 is slidingly housed. In particular the housing openings 20 are positioned on margin areas 21 of the bracket elements 12.

Fixing holes 18 are situated on the first plate portion 17, shaped so as to receive fixing elements suitable for allowing the removable fixing of each of the bracket elements 12 to the supporting body 7. The fixing elements can be of any type desired, for example of the VTPEI M4X8 type. In particular, two fixing holes 18 are envisaged for allowing a solid fixing of the plate elements 12 and preventing undesired slackening or rotations. Any suit- able number and/or dimension and/or positioning of the fixing holes 18 can be selected however.

The ejecting element 13 comprises an activation portion 23 which, in the extended position P, is interposed between the two bracket elements 12. An opposite portion 22, for example annular, suitable for resting on the first bracket element 12a, projects transversally from the activation portion 23.

The ejection device (1) comprises return means 24, which, in the illustrative and non-limiting embodiment described herein with reference to the enclosed Figures, comprises a spring 24, but which can alternatively comprise various types of elastic means. The return means, instead of the spring 24, can include other equivalent means such as, for example, an air cylinder. The spring 24 and the ejecting element 13 are configured to cooper- ate in impressing an ejection thrust on the screw 3 when the latter is released and is separated from the fixed comb element 4, as described more specifically hereunder.

The spring 24, in particular of the helicoidal type, is arranged coaxially with respect to the ejecting element 13, and has a first end resting against the opposite portion 22, and a second end which acts on the second bracket element 12b. The spring 24 is a compression spring and acts so as to push the opposite portion 22 against the first bracket element 12a, in order to maintain the ejecting element 13 in the extended position P, when there are no external forces on the ejecting element 13. When a thrust is exerted on the contact end 15, as will be seen more in detail further on, which is such as to overcome the mechanical resistance of the spring 24, the ejecting element 13 is moved towards the withdrawn position R, in which the contact end 15 is closer to the first bracket element 12a, and the activation portion 23 is at least partially projected beyond the second bracket element 12b. In this configuration, the return means 24, and consequently the ejection device 13, is charged with mechanical energy which can be used, as will be seen hereafter, to impart a propulsion to the threaded screw 3, evacuating it from the threaded machine 2.

It is obviously possible to configure the ejection de- vice 1 so that it functions with a traction spring, rather than with a compression spring, after suitable geometric modifications.

Thanks to the fact that the bracket elements 12 can be easily moved from the supporting body 7, the ejection element 13 can be rapidly substituted, for example when it is worn, to be substituted by a new one, or to substitute it with an ejecting element having a different length to be adapted to particular geometries of the threading machine and/or screws to be threaded, or simply to allow possible maintenance interventions of any kind.

The version of the ejection device 1 shown in Figure 5 is functionally and structurally similar to the version of Figure 4. This version differs in a different geometry of the supporting body 7, which can be more suitable for a different type of threading machine 2, and for a different geometry of the bracket elements 12. In particular, each bracket element 12 comprises a second plate portion 25, analogous to the first plate portion 17, but equipped with a single fixing hole 18, whose dimension can be suitably selected.

Each bracket element 12 of the version of Figure 5 also comprises a second elongated portion 26 which extends as an elongation of the first elongated portion 16.

At a lower end 27 of each second elongated portion 26, there is a second fixing body 28, which, by cooperating with the fixing body 18, prevents any possible undesired rotations of the bracket elements 12 due to the stress which is generated during the processing of the screws 3.

During functioning, the screw to be threaded 3 is placed, by means of a suitable conveying unit, not shown, in a first A position, or an entry position into the comb elements, in a start-up area 29 interposed between the movable comb element 5 and the fixed bed element 4. The movable comb element 5 is subsequently activated to move in the operative direction 0 towards the fixed comb element 4. In this phase, the screw 3 is compelled to roll with respect to the movable comb element 5 and the fixed comb element 4, receiving from these a forming action which is such as to generate the desired threading. During this operation, the screw 3, at a certain point, arrives close to the ejecting element 13 and intercepts the contact end 15, in a second position B, shown in Figure 2. From this moment on, the screw 3, compelled to advance due to the effect of the relative movement of the comb elements 4 and 5, exerts a thrust on the ejecting element 13 towards the withdrawn position R, progressively compressing the spring 24, until it reaches a third position C, or exit position from the comb elements, as shown in Figure 3. Close to run-end of the comb element 5, the screw 3, which, at this point, has now almost totally pushed the ejecting element 13 into the withdrawn position R and compressed the spring 24 mechanically charging it, becomes detached i.e. is no longer in contact with the fixed comb 4. In this way, as the screw 3 is now disengaged from the fixed comb element 4, the ejecting element 13 is no longer obstructed and is free to discharge onto the same screw 3 the mechanical energy accumulated in the spring 24. In particular, the spring 24 rapidly expands bringing the ejecting element 13 back to the protracted position P, and in this way acts on the screw 3 propelling it far from the supporting body 7, i.e. projecting it beyond the activation area 29, and therefore evacuating it from the threading machine 2.

At this point, the comb elements 4 and 5 can return to the initial configuration to effect a new processing on another screw.

The ejection device 1 according to the invention, with respect to the systems of the state of the art, is much more reliable in ensuring the ejection of the screws from the threading machine 2. Furthermore, the ejection device 1 is capable of preventing undesired jamming between the comb elements and thus avoiding possible undesired serious damage to the same machine or even accidents which endanger safety of the operators present around the ma- chine. Thanks to its constructive simplicity and high re^¬ liability, the ejection device 1 avoids long machine- stoppages which generally occur with the ejection systems of the state of the art. This leads to economical advantages also under the profile of production yields in the processing of screws.

The ejection device 1 according to the invention, moreover, proves to be capable of considerably decreasing the production costs of threaded screws, as it makes the use of the costly compressed air normally used in the state of the art, superfluous.

Furthermore, the ejection device 1, in addition to being simple and economical to construct, allows a considerable improvement in the environmental operating conditions. In particular, the ejection device 1, unlike the known ejection systems with compressed air, ensures low noise degrees and high cleanliness levels of the threading machines on which it is assembled.

Claims

1. An ejection device (1) suitable for ejecting a screw (3) after being threaded by a threading machine (2), comprising:

- supporting means (7) suitable for being assembled on said threading machine (2) ;

- ejecting means (13) supported by said supporting means (7) and suitable for coming into contact with said screw (3) ;

- return means (24) cooperating with said ejecting means ( 13 ) ;

- said ejecting means (13) being movable between a withdrawn position (R) with respect to said supporting means (7), towards which said ejecting means (13) are pushed by said screw (3) due to the movement impressed by said threading machine (2) so as to oppose and mechanically load said return means (24), and an extended position (P) at least partially with respect to said supporting means (7), towards which said ejecting means (13) are propelled by said return means (24) so as to expel said screw (3) from said threading machine (2).

2. The device according to claim 1, wherein said ejecting means (13) and said return means (24) are configured to impress an ejection thrust on said screw (3) starting from a position in which said screw (3) is separated from a fixed comb element (4) included in said threading machine (2) .

3. The ejection device according to claim 1 or 2, wherein said supporting means comprise a supporting body

(7) suitable for being applied to a movable comb element (5) of said threading machine (2), and wherein said ejecting means comprise an oblong element (13) slidingly supported by said supporting body (7) and configured so as to move parallel to an advance direction (0) of said movable comb element (5) .

4. The ejection device according to claim 3, wherein said oblong element comprises a bar or pivot element (13) suitable for extending during use, substantially or- thogonally to a longitudinal axis (L) of said screw (3) .

5. The ejection device according to any of the claims from 1 to 4, also comprising bracket elements (12) to movably connect said ejecting means (13) to said supporting means ( 7 ) .

6. The device according to claim 5, wherein said bracket means comprise a pair of bracket elements (12a, 12b) , parallel to each other and spaced, in which housing openings (20) are situated, suitable for slidingly receiving said ejecting means (13) said pair of bracket elements (12a, 12b) being removably fixed to said sup- porting means (7) by fixing means, and said supporting means (7) being removably assembled on said threading machine (2) by further fixing means.

7. The ejection device according to any of the claims from 1 to 6, wherein said return means (24) are interposed between a connecting portion (22) of said ejecting means (13) and a stationary portion (21) with which said return means (24) are in contact.

8. The ejection device according to any of the claims from 1 to 7, wherein said return means comprise elastic return means (24) .

9. The ejection device according to claim 8, wherein said elastic means comprise a helicoidal spring (24), arranged coaxially around said ejecting means (13), said helicoidal spring comprising a compression spring (24) or a traction spring.

10. The device according to any of the claims from 1 to 7, wherein said return means comprise pneumatic cylinder means .