MORETTI, Bruno (Corso Novara 178, Vigevano, I-27029, IT)
| CLAIMS 1. A punching machine (10) for sheet metal, comprising: a C-shape support frame (11) having means for supporting and moving metal sheets (14) into a cavity (13) between a lower arm (11 A) and a upper arm (11 B) of the C-shape support frame; a plurality of dies (15), removably housed into respective seats of the lower arm (11 A); a plurality of punching units (16), removably housed into respective seats of the upper arm (11 B), axially aligned to respective dies (15) of the lower arm; and a support member (23) for a plurality of control cylinders (17) for the punching units (16), characterised in that: the support member (23) with the control cylinders (17) for the punching units (16) is connected to the support frame (11) of the machine to rotate around a horizontal axis (28); and in that the machine (10) comprises actuation means (25), operatively connected to the support member (23) for the control cylinders (17) of the punching units (16), to rotate the support member (23) with the control cylinders (17), between a lowered position wherein each cylinder (17) is operatively connected to at least one punching unit (16), and a raised position wherein the support member (23) with the control cylinders (17) are angularly spaced apart from the punching units (16). 2. The punching machine according to claim 1 , characterised in that the support member (23) of the control cylinders (17) for the punching units (16), may be turned upwards by an angle ranging between 92° and 115°. 3. The punching machine according to claim 1 , characterised in that the dies (15) and the punching units (16) are aligned according to one or more rows. 4. The punching machine according to claim 1 , characterised by comprising means (32, 33) for blocking the support member (23) of the control cylinders (17) for the punching' units (16), in the lowered working position. 5. The punching machine according to claim 4, characterised in that the blocking means (32, 33) comprises small posts (32) for resting the support member (23) for the control cylinders (17), in which the posts (32) extend from the upper arm (1 1 B) of the support frame (10) of the punching machine. |
BACKGROUND OF THE INVENTION The present invention relates to the punching machines for metal sheet, and in particular is directed to a particular conformation of the machine, by which certain operative parts are made easily accessible for maintenance and/or replacement operations. STATE OF THE ART
A punching machine for metal sheets substantially comprises a C-shape supporting frame having means for support the metal sheet to be punched, which metal sheet is moved, according to a prefixed working program, into a cavity of the support frame between a lower arm and a upper arm.
A plurality of dies are removably housed within respective seats of the lower arm of the punching machine and a corresponding plurality of punching units are removably housed within respective seats of the upper arm; the machine further comprises control cylinders, axially aligned or suitable for being axially aligned with the respective punching units.
A punching machine of the mentioned type is disclosed for example in EP- A-1.445.042 and US-A-5.301.585.
One of the problems normally existing in punching machines of the mentioned type, relates to the capability of easily gaining access and operating on certain functional parts, for maintenance operations, in particular for maintaining and/or replacing operations of the punching units.
OBJECTS OF THE INVENTION
The existing punching machines exhibit in general a quite complex structure and conformation, i.e. such to make difficult for an operator to gain access to the punching units; consequently, the ' maintaining operations, besides resulting difficult, require relatively long operating times, with a consequent stop of the machine and of the productive process.
Consequently, the need exists for finding a new and different configuration of a punching machine that is characterised by an extreme simplification and a greater ease for an operator of gaining access to maintaining and/or replacing operations of the punching units or other functional and/or structural parts of said punching machine.
A further object of the invention is to provide a structurally and functionally improved sheet metal punching machine, that enables the operative times to be comparatively reduced, enabling at the same time an operator to operate at very high safety.
SUMMARY OF THE INVENTION
All the above has been made possible by a punching machine according to claim 1 , comprising:
a C-shape support frame having means for supporting and moving metal sheets into a cavity formed between a lower arm and a upper arm of the C-shape supporting frame;
a plurality of dies, removably housed within respective seats of the lower arm;
a plurality of punching units, removably housed within respective seats of the upper arm, axially aligned to respective dies of the lower arm; and
a support member for a plurality of control cylinders for the punching units, characterised in that:
the support member with the control cylinders for the punching units is connected with the support frame of the machine to rotate around a horizontal axis; and
in that the machine comprises actuation means, operatively connected to the support of the control cylinders for the punching units, to rotate the support member with the control ' cylinders, between a lowered position wherein each cylinder is operatively connected to at least one punching unit, and a raised position wherein the support member with the control cylinders is angularly spaced apart from the punching unit.
Preferably, an actuating cylinder is associated with each punching unit, providing a disposition of the dies and the punching units in aligned positions along one or more rows parallel to a movement direction for the metal sheets to be punched.
BRIEF DESCRIPTION OF DRAWINGS
These and further features of the punching machine will better result from the following description, with reference to the example of the enclosed drawings, wherein:
Figure 1 is a side view of the machine with the support member for the control cylinders for the punching units in a lowered position;
Fig. 2 is a front view of the machine, with the punching units and the dies represented in cross section according to the line 2-2 of figure 1 ;
Fig. 3 is a view, from above, of figure 1 ;
Fig. 4 is an enlarged detail of figure 1 ;
Fig. 5 is a side view of the machine with the support member for the control cylinders for the punching units in a upwards turned position.
DETAILED DESCRIPTION OF THE MACHINE
As shown in figures 1 to 3, the punching machine, generally indicated by 10, comprises a C-shape support frame 11 , anchored to a support base 12. The C-shape support frame 11 comprises a lower arm 11A and an upper arm 11 B, which upper arm 11 B is parallely and spaced apart arranged with respect to said lower arm 11A, between which arms (11A, 11 B) a longitudinal cavity 13 is provided for introducing a metal sheet 14, figure 4, that has to be subjected to punching operations according to a working program stored and controlled by an electronic control unit for the entire apparatus.
A plurality of dies 15 are removably housed within respective seats formed in the lower arm 11A of the support frame of the machine, whereas a plurality of punching units 16 are removably housed within respective seats of the upper arm 11 B.
In the shown case, both the dies 15 and the respective punching units 16 are arranged in positions aligned on two rows that parallely extend to a moving direction for the metal sheet 14, for example according to a longitudinal axis of the machine; however, the dies 15 and the punching units 16 can have any other arrangement, different from the shown. Furthermore, both the dies 15 and the punching units 16 can be of any type and/or dimension, as shown for example in figure 1 , according to the type and the dimensions of the hole and the opening to be produced in the metal sheet 14. The machine is further suitable for moving the metal sheet 14 along one or two directions, individually or jointly, as well as for operating one or more punching units 16 sequentially or simultaneously, by suitable hydraulic or pneumatic control cylinders.
Consequently, as shown in the different figures, the punching machine comprises a plurality of double-acting cylinders 17, for controlling the various punching units 16. Preferably, a control cylinder 17 is provided that is axially aligned, or suitable for being axially aligned, with a respective punching unit 16; however, one or more punching units are not excluded that can be simultaneously operated by a single cylinder 17. As already disclosed, the dies 15, the punching units 16 and the control cylinders 17 can be of any type and anyway conformed, provided that the cylinders 17 are suitable for being operatively engageable and disengageable from the punching units 16, for the reasons disclosed below. By mere way of example, as shown in figure 4, representing an enlarged detail of figure 1 , where the same reference numbers has been used as the preceding figures in order to indicate similar or equivalent parts, each punching unit 16 comprise a punch 18, vertically movable within a sheet pressure sleeve 18' that is upwardly pushed by a system of springs, not shown. The punch 18 exhibits an annular flange 19 that rests against annular elements 20 sliding along collar screws 21 , said collar screws 21 being laterally arranged and screwed into respective holes of the sheet pressure sleeve 19. Each punch 18 is upwardly pushed by springs 22, coaxial to the screws 21.
According to the main feature of the present invention, the cylinders 17 for controlling the punching units 16 are suitable for being operatively engageable and disengageable, as well as are supported for being moved to and from a respective punching unit 16, by a simple angular movement for turning upwards their support member, around a horizontal axis of rotation.
More particularly, the control cylinders 17 are removably secured within respective housing seats of a support member 23, consisting of a large plate supported by the support frame 11 of the machine to rotate around a horizontal axis 24 that extends parallel to the rows of punching units 16. A pair of hydraulic cylinders 25 or other actuators are pivoted in 26 to a bracket 26' at a rear extension of the frame 11 of the machine, whereas the rods 27 are pivoted in 28 with the support plate 23 for the cylinders 17.
From the detail of figure 4 it is further noticed that each cylinder 17 exhibits a piston 29 whose rod end with a head 30 that passes through a hole 31 of the support plate 23, in order to come into contact with the rear end of a respective punch 18.
Small hollow posts 32, screwed into the upper arm 11 B, provide a reference abutment for the plate 23, in the lowered position, enabling said plate 23 to be blocked by screws 33.
Figures 1 and 5 of the drawings as a whole show the main feature of the punching machine according to the invention, i.e. the capability of the support plate 23 for the control cylinders 17 for the punching units 16, to rotate around the horizontal axis 24, for a turning movement between two angular positions; in particular between a first lowered position, figure 1 , wherein the plate 23 with the cylinders 17 is blocked on the small support post 32, wherein the cylinders 17 are axially aligned with respective punching units 16, and a second raised position, figure 5, wherein the plate 23 with the cylinders 17 is angularly spaced apart from the punching units 16.
This solution, with respect to other known machines, results very advantageous both for its own constructive simplicity, and because said solution gives an operator a total free access to maintenance and/or replacing operations of the punching units 16.
Although the cylinders 25, by locking the oil circulation, enable the plate 23 to be maintained in the raised position, without any risk that said plate 23 can fall down forwards, in order to ensure a greater safety, it is preferable that the support plate 23 of the control cylinders 17 for the punching units 16 be turned and caused to rotate upwards by an angle greater than 90°, for example ranging between 92° and 115°; as a consequence, in the event that the hydraulic circuit of the cylinders 25 suffers a failure, the self-weight of the plate 23 and the cylinders 17 would cause said plate 23 and said cylinders 17 to fall rearwards.
Consequently, from all said and shown above, it results clear, that a structure of extreme simplicity has been provided for a metal sheet punching machine, the structure being high functional for intervention and provided with a high safety degree; therefore, as the feature of the upwards turning movement of the support plate of the control cylinders for the punching units, together with the cylinders remain unchanged, other changes and/or variations can be made to the machine as a whole, or parts, without thereby departing from the enclosed claims.