WO1999064226A1

WO1999064226A1 - Emergency brake for mechanical presses

Info

Publication number: WO1999064226A1
Application number: PCT/IT1999/000168
Authority: WO
Inventors: Renzo Cipriani; Giuseppe Paolini
Original assignee: Renzo Cipriani; Giuseppe Paolini
Priority date: 1998-06-12
Filing date: 1999-06-10
Publication date: 1999-12-16
Also published as: ITMC980062A0; EP1003634A1; ITMC980062A1; AU4390399A

Abstract

The present invention relates to an emergency brake for mechanical presses, capable of blocking the mobile organs of the press in all stop positions, as well as deactivating the start controls of the press, as long as it is inserted.

Description

Emergency brake for mechanical presses.

The present patent application relates to a emergency brake for mechanical presses, capable of blocking the mobile organs of the press in all stop positions, as well as deactivating the start controls of the press, as long as the brake is inserted. The emergency brake according to the present invention originates from the need to comply with the current safety regulations existing in the machine tool sector. According to the regulations, the machines in which the loading, adjusting, piece-changing, cleaning, repairing and maintenance operations require the operator to enter the machine or interpose his body between its mobile organs must be equipped with devices capable of absolutely ensuring the lock position of the machine and its organs during the execution of such operations.

The emergency brake according to the present invention comprises a vertical axis bar, whose base ends with a head which is engaged inside an enclosure, to be fixed to the mobile organ of the press, while the stem is inserted and slides inside a housing drive sleeve, to be fixed on the bearing frame of the press at a higher height compared to the height of the mobile organ in its upper end stroke position. The bar features a helical threading which is laterally interrupted on a diametrically opposed pair of longitudinal facetings, so that the section of the threaded bar with a transversal plane features four sides, with two pairs of identical opposed sides: two parallel rectilinear sides on the opposed facetings and two sides with arched profile on the opposed teeth of the threading. The housing drive sleeve of the threaded bar houses a special nut, capable of making short vertical strokes and engaging with the threaded bar. More exactly, the internal threading of the nut is interrupted on a diametrically opposed pair of deep longitudinal grooves, so that the section of the nut with a transversal plane features two opposed toothed profiles, spaced by two opposed niches.

The emergency brake according to the present invention also comprises a collar, equipped with maneuvering lever, splinted on the bar immediately above the enclosure in which the lower head of the bar is engaged.

This means that the 90° rotation of the collar determines the identical oscillation of the bar, with consequent engagement or disengagement of the bar threading with the nut located inside the housing drive sleeve of the threaded section of the bar.

It appears obvious that when the emergency brake according to the present invention is not inserted, the nut does not engage with the threaded bar and therefore the threaded bar is free to follow the mobile organ of the press in its alternate vertical strokes. In order to insert the emergency brake according to the present invention it is only necessary to drag the bar into a 90° rotation, so that the two opposed toothed sectors of the bar engage with the corresponding sectors of the nut located inside the housing drive sleeve of the bar. It is clear that in the latter case the vertical translation of the bar, together with the translation of the mobile organ of the press, is prevented by the mechanical lock, represented by the helical coupling between nut and threaded bar, thus absolutely preventing the free fall of the mobile organ of the press, whose weight would be entirely supported by the emergency brake according to the present invention. The emergency brake according to the present invention is equipped with appropriate means, which are described in details below, capable of favoring the easy, safe engagement between the teeth of the nut and the teeth of the threaded bar in all stop positions of the mobile organ of the press. Finally, it must be underlined that the emergency brake according to the present invention also comprises a microswitch that is excited when the brake is inserted, with the task of emitting a signal which determines the temporary deactivation of the start controls of the press, as long as the brake is inserted. This means that the press cannot be operated with the start buttons located on the control panel if the emergency brake is inserted. For major clarity the description of the emergency brake according to the present invention continues with reference to the enclosed drawings, which are intended for purposes of illustration and not in a limiting sense, whereby:

- Figure 1 is half a view and half a cutaway view of the emergency brake according to the present invention in the inserted position;

- Figure 2 is a top view of Figure 1 , according to the ll-ll direction indicated in Figure 1 ; - Figure 3 is a cutaway section of Figure 1 with the Ill-Ill plane of Figure 1 ;

- Figure 4 is a cutaway section of Figure 1 with the IV-IV plane of Figure 1 ;

- Figure 5 is half a view and half a cutaway view of the emergency brake according to the present invention in the non-inserted position;

- Figure 6 is a top view of Figure 5, according to the VI-VI direction indicated in Figure 5;

- Figure 7 is a cutaway view of Figure 5 with the VII-VII plane of Figure 5;

- Figure 8 is a cutaway view of Figure 5 with the VIII-VIII plane of Figure 5;

- Figure 9 is a cutaway view of the threaded bar, in the disengaged position with the dowel, which is shown in a view; - Figure 10 is a cutaway view of Figure 9 with the X-X plane of Figure 9;

- Figures from 11 to 14 show the engagement sequence between the teeth of the nut and the teeth of the threaded bar, during the 90° rotation of the bar;

- Figures 15 and 16 are two different cutaway views of a device for the automated rotation of the threaded bar; - Figure 17 is half a view and half a cutaway view of the emergency brake according to the present invention, in the inserted position, according to a different constructive version, in which the threaded bar only translates, without rotating, with the special nut capable of 90° rotation;

- Figure 18 is a cutaway view of Figure 17 with the A-A plane; - Figure 19 is the same as Figure 18, with the only difference that the special nut is rotated by 90° with respect to the position shown in Figure 18;

- Figure 20 is a cutaway view of a detail of an actuator for the automatic movement of the nut in the second alternative version. With reference to Figures from 1 to 8, the emergency brake according to the present invention comprises a vertical axis bar (1), whose base ends with a head (2), made up of a spherical nut, engaged in a pair of opposed covers (3), housed in a bell-shaped enclosure (4), which externally features a base flange (4a) used to fix it to the mobile organ (M) of the press. The bar (1) is inserted and freely slide and rotates inside a housing drive sleeve (5), which externally features a base flange (5a) used to fix it to the fixed bearing frame (F) of the press. The bar (1) features a helical threading (1a), which is laterally interrupted on a diametrically opposed pair of longitudinal facetings (1b), so that the section of the threaded bar with a transversal plane features four sides, with two pairs of identical opposed sides: two parallel rectilinear sides on the opposed facetings (1b) and two sides with arched profile on the opposed teeth of the threading (1a), as shown in Figure 9.

The housing drive sleeve (5) of the threaded bar (1) houses a special nut (6), capable of engaging with the threaded bar (1) and making short vertical strokes with respect to the sleeve (5), guided by an annular series of keys (7), partly recessed inside longitudinal grooves especially located on the external side of the nut (6) and partly recessed inside longitudinal grooves especially located on the internal side of the sleeve (5), as shown in Figures 3 and 7. The nut (6) is located between two return springs - an upper spring (8) and a lower spring (9) - which push it and return it to its centered rest position as soon the engagement of the nut (6) with the bar (1) ends. More exactly, the internal threading of the nut (6) is interrupted on a diametrically opposed pair of deep longitudinal grooves (6a), so that the section of the nut (6) with a transversal plane features two opposed toothed profiles (6b), spaced by two opposed niches (6a). With particular reference to Figures 2 and 6, the drive action of the bar (1) inside the sleeve (5) is entrusted to two opposed pairs of bearings (10) with horizontal axis, supported by a sleeve (11) and sliding on the facetings (1b), capable of guiding the bar (1) during its vertical strokes jointly with the mobile organ (M) of the press. The sleeve (5) also houses an opposed pair of bearings (12) with vertical axis, supported by the sleeve (11) and sliding in an annular groove (5b) located on the internal wall of the sleeve (5), designed to prevent the free extraction, in axial direction, of the support sleeve (11), which is centered inside the sleeve (5) through the interposition of a needle bearing (13).

The emergency brake according to the present invention also comprises a collar (14), splinted on the bar (1) immediately above the enclosure (4) in which the lower head (2) of the bar is engaged. In the preferred embodiment of the invention illustrated in Figure 2, the collar is manually operated by means of a maneuvering lever (15), screwed onto a radial hole (14a) located on the external surface of the collar (14). In the constructive version illustrated in Figures 15 and 16, the collar (14) is operated by means of an actuator, featuring an external toothing (14b), which engages with a worm screw (16), operated by a direct current motor (17).

The emergency brake according to the present invention is equipped with means capable of favoring the easy, safe engagement between the teeth of the nut and the teeth of the threaded bar in all stop positions of the mobile organ of the press. With particular reference to figures 9 and 10, the means are represented by one or more opposed pairs (in this case two pairs) of dowels (18) with horizontal axis, whose diameter is equal to the thickness of the threads (6b) of the nut (6), where the dowels (18) are radially fitted in such a position that a short semi-cylindrical portion of their ending section (18a) protrudes in one of the two ends of the niches (6a), being exactly located between two consecutive grooves of the threading (6b) of the nut (6). The threads (1b) of the bar (1) feature a pointed attachment section (1B) so that, in case of interference between the attachment section (1 B) and the ending section (18a) of the dowels (18) - as illustrated in Figures from 11 to 14 - the attachment section (1 B) tends to deviate and slide either above or below the ending section (18a), which is respectively raised or lowered together with the nut (6), in spite of the counteracting action of one of the return springs (8 or 9).

In Figure 13 the nut (6) is raised by the forward movement of the pointed attachment section (1 B), which, in this case, is guided until it enters the groove immediately below the ending section (18a) of the dowel (18), as shown in Figure 14.

In order to indicate the accidental free fall of the mobile organ of the press when the emergency brake is inserted, the brake is equipped with a system of proximity microswitches capable of indicating with acoustic and/or luminous signals the presence of breakage or failure allowing for the free fall of the mobile organ, so that the mobile organ is temporarily supported by the emergency brake only.

The view in Figure 1 illustrates the free fall of the mobile organ of the press with the emergency brake in the inserted position. In this case the bar (1), jointly with the mobile organ (M) of the press, drags the nut (6) which, at the end of the descending stroke, unloads its entire thrust on the bottom of the sleeve (5), flanged to the fixed frame (F) through the interposition of a Belleville washer (19), which is completely pressed.

The emergency situation is detected by a proximity microswitch (20), externally applied on the flange (5a) of the sleeve (5) and designed to intervene when the flange (5a) is fitted against the plane of the fixed frame (F) because of the complete pressure of the Belleville washer (19). The microswitch (20) emits an acoustic and/or luminous signal, which indicates the failure and emergency condition. As already mentioned above, the emergency brake according to the present invention also comprises a microswitch that is excited when the brake is inserted, with the task of emitting a signal which determines the temporary deactivation of the start controls of the press, as long as the brake is inserted. The microswitch marked with number (21) in the figures above is perimetrically fixed on the cap (22) that closes the upper opening of the sleeve (5) and cooperates with a projection (21a) located on the support dowel of one of the bearings (12) dragged into 90° rotation together with the support sleeve (11), when the bar (1) is rotated to insert or remove the ^■r 1 ~

emergency brake.

At this purpose, it must be noted that the projection (21a) is not visible in Figure 6 (which illustrates the position of the bar (1) when the brake is not inserted) since it is located immediately below the microswitch (21), which remains inactive until the presence of the projection (21a) below is detected. On the contrary, in Figure 2 the projection (21a) is rotated by 90° with respect to its position in Figure 6, since Figure 2 shows the position of the bar (1) when the brake is inserted. In this case, the microswitch (21) no longer detects the presence of the projection (21a) below and emits a signal that determines the temporary deactivation of the start control of the press, as long as the brake remains inserted.

Figures from 17 to 19 describe another constructive version of the emergency brake according to the present invention, which differs from the first version only because the coupling between the bar (1) and the nut (6) is determined by the rotation of the nut - and not of the bar - as in the version described above.

In this second version the bar (1) no longer rotates around its axis and is therefore directly screwed onto the mobile organ (M) of the press through the interposition of a fork (23). For this reason, in this version the sleeve (5) does not contain the support sleeve (11) for the pair of bearings (12), which are not present.

In this version the two opposed pairs of bearings (10) that guide the strokes of the bar (1) are directly assembled onto the cap (22a) of the upper opening of the sleeve (5), inside which the nut (6) is centered by means of elastic bands (29), with the possibility of rotating and axially sliding, between the usual pair of springs (8 and 9).

The nut (6) is manually dragged with a crank (24) which ends with a semicircular fork (24a), fixed above the nut (6) with screws (25). The fork (24) is introduced into the sleeve (5) by means of a slot (26) located on the external wall of the sleeve, whose extension is slightly larger than an arc of a circumference quarter. In this case the microswitch (21) is fixed on the external surface of the sleeve (5), immediately below the crank (24), whose presence it detects, with the emergency brake in the inserted (see Figure 19) or non-inserted position (see

Figures 17 and 18).

In case of automatic movement of the nut (6), the nut features an external toothed crown (26), as shown in Figure 20, which engages with a worm screw

(27), operated by en electric motor (28), anchored on the external surface of the sleeve (5), which features a slot (28) used by the screw (27) to engage with the toothed crown (26).

It is understood that, although expressly designed for mechanical presses, the emergency brake according to the present invention can be effectively and usefully used in any machine or installation equipped with mobile organs with alternate translating movement.

Claims

1) Emergency brake for mechanical presses, characterized in that it comprises:

- a vertical axis bar (1), whose base ends with a head (2), housed in a bell- shaped enclosure (4), which externally features a base flange (4a) used to fix it to the mobile organ (M) of the press, whose stem features a helical threading (1a), which is laterally interrupted on a diametrically opposed pair of longitudinal facetings (1b);

- a sleeve (5), externally featuring a base flange (5a) used to fix it to the fixed bearing frame (F) of the press, inside which the threaded bar (1) vertically slides and rotates by 90°, guided by a series of bearings (10 and 12) located inside the sleeve (5);

- a special nut (6), capable of engaging with the threaded bar (1) and making short vertical strokes with respect to the sleeve (5), guided by an annular series of keys (7), partly recessed inside longitudinal grooves especially located on the internal side of the sleeve (5) and partly recessed inside longitudinal grooves especially located on the external side of the nut (6), whose internal threading (6b) is interrupted on a diametrically opposed pair of deep longitudinal grooves (6a);

- a pair of springs (8 and 9) housed inside the sleeve (5), an upper spring (8) and a lower spring (9), which push and return the nut (6) located between them to its centered rest position as soon as the engagement of the nut (6) with the bar (1) ends;

- a collar (14) splinted on the bar (1) immediately above the enclosure (4), equipped with maneuvering means to drag it in rotation with respect to the vertical axis;

- one or more opposed pairs of dowels (18) with horizontal axis, whose diameter is equal to the thickness of the threads (6b) of the nut (6), where the dowels (18) are radially fitted in such a position that a short semi-cylindrical portion of their ending section (18a) protrudes in one of the two ends of the niches (6a), being exactly located between two consecutive grooves of the threading (6b) of the nut (6), it being provided that the threads (1 b) of the bar (1) features a pointed attachment section (1B);

- a microswitch (21) that is excited when the brake is inserted, with the task of emitting a signal which determines the temporary deactivation of the start controls of the press, as long as the brake is inserted.

2) Emergency brake for mechanical presses, according to claim 1 , characterized in that the collar (14) externally features a threaded radial hole (14a) to which a maneuvering lever (15) is screwed.

3) Emergency brake for mechanical presses, according to claim 1 , characterized in that the collar (14) features an external toothing (14b), which engages with a worm screw (16), operated by a direct current motor (17).

4) Emergency brake for mechanical presses, characterized in that it comprises:

- a vertical axis bar (1), whose base is anchored to the mobile organ (M) of the press with the interposition of a fork (23), whose stem features a helical threading (1a), which is laterally interrupted on a diametrically opposed pair of longitudinal facetings (1b);

- a sleeve (5), externally featuring a base flange (5a) used to fix it to the fixed bearing frame (F) of the press, inside which the threaded bar (1) vertically slides, guided by a series of bearings (10) with horizontal axis, assembled on the cap (22) of the upper opening of the sleeve (5);

- a special nut (6), capable of engaging with the threaded bar (1), rotating and making short vertical strokes with respect to the sleeve (5), provided with elastic bands (29) used to center the nut (6), whose internal threading (6b) is interrupted on a diametrically opposed pair of deep longitudinal grooves (6a);

- a pair of springs (8 and 9) housed inside the sleeve (5) - an upper spring (8) and a lower spring (9) - which push and return the nut (6) located between them to its centered rest position as soon as the engagement of the nut (6) with the bar (1) ends; - means used to drag the nut (6) in rotation;

- one or more opposed pairs of dowels (18) with horizontal axis, whose diameter is equal to the thickness of the threads (6b) of the nut (6), where the dowels (18) are radially fitted in such a position that a short semi-cylindrical portion of their ending section (18a) protrudes in one of the two ends of the niches (6a), being exactly located between two consecutive grooves of the threading (6b) of the nut (6), it being provided that the threads (1b) of the bar (1) features a pointed attachment section (1 B);

- a microswitch (21) that is excited when the brake is inserted, with the task of emitting a signal which determines the temporary deactivation of the start controls of the press, as long as the brake is inserted. 5) Emergency brake for mechanical presses, according to claim 4, characterized in that the actuating means of the nut (6) comprise a crank (24) which ends with a semicircular fork (24a), fixed above the nut (6) with screws (25) and introduced into the sleeve (5) by means of a slot (26) located on the external wall of the sleeve, whose extension is slightly larger than an arc of a circumference quarter. 6) Emergency brake for mechanical presses, according to claim 4, characterized in that the actuating means of the nut (6) comprise a worm screw (27), operated by en electric motor (28), anchored on the external surface of the sleeve (5), which features a slot (28) used by the screw (27) to engage with a toothed crown (26) especially located on the external wall of the nut (6).

7) Emergency brake for mechanical presses, according to the previous claims, characterized in that it comprises a proximity microswitch (20), externally applied on the flange (5a) of the sleeve (5) and designed to intervene when the flange (5a) is fitted against the plane of the fixed frame (F) because of the complete pressure of the Belleville washer (19) located between the frame and the flange (5a); it being provided that the signal emitted by the microswitch (20) determines the activation of an acoustic and/or luminous signal.