Press with compressed air system for clamping and unclamping cornice brake tools

Abstract: In the cornice brake are present rows of punches, dies and modular units constituting extensions of punches and clamping jaws for said punches and extensions. The compressed air system is characterized in that: clamping of the jaws takes place through bolts put in tension by means of compressed air cylinder actuators; supply of the compressed air cylinders of the actuators takes place through ducts made inside the body of the jaws and/or said extensions and through tubes running between jaws and/or said extensions of each side-by-side pair; and the tubes running between said extensions are metal tubes with straight horizontal axis partly running between extensions of each side-by-side pair and partly inserted in cavities made in the sides of said extensions with the capability of airtight running within said cavities.

Description: Field of the Invention The present invention relates to a press with a compressed air clamping and unclamping system for cornice brake tools. A press according to the pre-characterising part of claim 1 is known in the art, for example, from the leaflet "Presse plieuses synchronisées à CNC" of the film Colgar S.p.A. Background For cold working by bending of sheet metal pieces, presses, termed 'cornice brakes', using pairs of appropriately shaped tools (punches and dies) are commonly used. In these machines the various processing phases require frequent operations of replacement or lateral shifting of the tools. These operations are usually performed either by entirely manual procedures requiring long pauses for loosening and then clamping of numerous modular unit bolts for clamping the tools or by clamping and loosening systems for the modular units with hydraulic control. These hydraulic control systems, if on the one hand they allow significantly shortened times for replacement and moving of the tools, on the other hand they display some shortcomings among which are: the necessity of a pressurized fluid supply and distribution system implemented with tubes designed to resist high pressures (150-200 atm) running outside the mechanical parts of the machine with supply independent of any modular unit and resulting in reduction of the useful handling space available to the work being processed; and the high cost of conversion of brakes already operating with entirely manual control to the hydraulic control system and the oil leaks which might occur at the system seals. Object of the invention The Object of the present invention is to realize a system for fastening cornicebrake tools free of the above mentioned shortcomings. Summary of the invention The press with compressed air system in accordance with the present invention is defined in claim 1. Other solutions related to preferred embodiments are set forth in the annexed subsidiary claims. Brief description of the drawings To clarify the innovative principles of the present invention and its advantages compared with the known art there is described below with the aid of the annexed drawings a possible embodiment thereof by way of nonlimiting example. In the drawings FIG 1 shows a front view of a cornice brake of known type; FIG 2 shows an enlarged view of a pair of punch and die tools of FIG 1; FIG 3 shows a partial front view of the rows of the clamping jaws of the extensions, of the extensions and of the punch clamping jaws in accordance with an embodiment of the present invention; FIG 4 shows an enlarged front view of two adjoining extensions in accordance with an embodiment of the present invention and of the associated punch clamping jaws; FIGS 5 and 6 show a front and a top view of a die clamping system in accordance with an embodiment of the present invention; FIG 7 shows a cross section view (in the upper part) of two modules of FIG 3 and (in the lower part) of a module of FIGS 5 and 6; FIG 8 shows an embodiment of the pressurized gas supply inlet at the left-hand end of a row of modules; FIG 9 shows an embodiment of the supply passage from the module of a row to the next module; FIGS 10a-10c show another embodiment of the extension and of the lower compressed air cylinder actuator. Example of a cornice brake of known type FIG 1 shows diagramatically a front view of a cornice brake of known type with entirely manual tool clamping and loosening procedure. The various component parts thereof are as follows: 1 and 2: indicate punch and die rows respectively forming part of two work stations and embodied at each station by means of modular units (optionally of subdivided modularity) termed hereinafter merely 'modules' in a number dependent upon the length of the zone of the metal sheet to be bent and with highprecision ground profile so as to be mutually interchangeable; the example in the figure shows a first station consisting of two pairs of punch and die modules brought near together and a second station consisting of a single pair of punch and die modules (with a profile not necessarily identical to the profile of the first two pairs); 3': indicates a row of plates acting as punch extension elements termed also 'extensions' and also provided through modular units and having the same profile and width and in a number such as to provide a total width not less than the total width of the underlying punch modules; 4 and 5: indicate the plunger and bed respectively of the press; 6': indicates a row of jaws for jointing and clamping the spigot of each 'punch' module to the overlying corresponding 'extension' module; 8': indicates a row of jaws for jointing and clamping each 'extension' module to the plunger head and arranged in succession along the entire plunger head; 11: indicates a supporting bar for the die modules; 10: indicates bolts for setting the position of the die modules on the bar 11; 12: indicates brackets fastened to the bar 11 supporting the bolts 10; and 7', 9' and 13: indicate clamping bolts. FIG 2 shows diagramatically but in enlarged scale and in greater detail a pair of punch and die tools of FIG 1 in a cross section along plane of cut AA of FIG 1. Therein the punch and die profiles are shaped for bending a metal sheet 14 into box form. Indeed, the figure shows how the cross section of the sheet 14 appears at the end of the last of four bending steps with the plunger 4 in the lower end of travel position. EMBODIMENTS OF THE PRESENT INVENTION FIGS 3 to 9 show an embodiment of the press with compressed air system for clamping tools in accordance with the present invention. Therein the reference numbers for the punches, dies, plunger and die supporting bar are the same as those of FIGS 1 and 2. With respect to the prior art represented in FIGS 1 and 2 the clamping system in accordance with the embodiment of the present invention displays the following principal similarities and differences which are discussed in greater detail with reference to the above mentioned FIGS 3 through 9, as follows: the modular units rows constituting punches, dies, extensions and clamping jaws for punches and extensions are still present; jaw clamping still takes place through bolts which however are put under tension not by manual screwing but through compressed air cylinder actuators; supply to the compressed air cylinders of the actuators takes place through channels made in the body of the jaws and/or of the extensions and through tubes running between jaws and/or extensions of each of their sidebyside pairs; the tubes running between the extensions are metal tubes with straight horizontal axis partly running between extensions of each sidebyside pair thereof and partly inserted in cavities made in the sides of the extensions with the capability of airtight running within the above mentioned cavities; and clamping of the die modules in pairs of locators locking the modules in the correct position on the support bar is performed not by tightening bolts but by clamping jaws having modular structure and compressed air actuators acting on the clamping jaws and fed through channels made in the clamping jaws and by means of tubes running between the jaws of each sidebyside pair thereof. The embodiment is now discussed in detail with reference to the figures. FIG 3 shows a partial front view of the rows of extension clamping jaws 8, the rows of extensions 3 and the rows of punch spigot clamping jaws 6 corresponding respectively to the jaws 8', extensions 3' and jaws 6' of FIG 1. FIG 4 also shows an enlarged front view of a partial cross section of two neighboring extensions 3a and 3b and of the associated spigot clamping jaws 6a and 6b for the underlying punch modules. Extension clamping jaws FIG 7 shows in its upper part a cross section of two modules of FIG 3 along plane of cut BB of FIG 3. The above mentioned figures show that the clamping jaw 8'' of the extension 3'' has two bolts 9 and 9'' which, to achieve clamping, are placed under tension not by tightening the bolts (as in manual control systems) but by operation of a compressed air cylinder actuator A8 of which 10 indicates the piston, 25 the piston seal and 12 the cylinder chamber side wall. As shown in FIGS 3 and 4 the cylinder chamber side wall runs along the edge of the jaw 8'' and is fastened thereto by four bolts 21. The piston 10 seen from the front has a rounded rectangular shape at the minor sides and is traversed by two bolts 9 and 9'' screwed on to the head of the plunger 4 and acting as rods for the piston. The compressed air cylinder chamber A8 at the moment of clamping is supplied with pressurized gas (air) through a cylindrical duct 14' passing along the plate constituting the jaw 8'' and in communication with the cylinder chamber through the hole 13. Since the vertical cross section of the cylinder chamber A8 involves a large part of the surface of the jaw 8'' it is understandable that relatively low pressures (e.g. 6 atm) of the pressurized gas are sufficient to achieve effective clamping. As shown in FIG 3 the row of modular units constituting the extension clamping jaws 8 consists of a succession of such modules located substantially sidebyside. Supply of pressurized gas to the chambers of the associated compressed air cylinders takes place not independently module by module but serially. This means with one input in one or both of the modules placed at the ends of the row and with a gas supply passage from one module to the next through tube unions inserted in part in the outlet ends of the duct 14' of a module and in part in the input end of the duct 14' of the next module. FIG 8 shows an embodiment of the pressurized gas supply input in the jaw located at the left end of the jaw row 8. Therein the meaning of the various parts is as follows: 81: indicates an L-shaped inlet fitting; 82: indicates a mouthpiece coupling; 83 : indicates an O-ring type seal to ensure air tightness; and 84: indicates a seal screw for the mouthpiece coupling. FIG 9 shows an embodiment of the pressurized gas supply passage from one module to the next with a metal connecting tube 94 partly inserted in the end 95 of the pressurized gas duct in a module (e.g. duct 14' of FIG 7). The figure shows only the inlet of the tube in the right-hand module. However, a specular representation also applies for the left hand module tube inlet. Therein the meaning of the various parts is as follows: 91: indicates metal rings for coupling of the walls of the hole with the metal inlet tube; 92: indicates an O-ring type seal to ensure compressed air tightness of the coupling; and 93: indicates a seal screw for the external ring 91. Extensions and punch clamping jaws The embodiment peculiarities of the extensions and punch spigot clamping jaws are shown in FIGS 3, 4 and 7. In FIG 7 the meanings of the parts associated with an extension 3" and a clamping jaw 6" are as follows: 3.1 and 3.2: indicate plates in which the extension has been divided for the sake of construction simplicity; accordingly 3.1 is the part designed to be held by the jaw 8" and 3.2 is the part designed to withstand the thrust exerted on the tip of the punch during processing; A6 : indicates a compressed air cylinder for control of clamping of the jaw 6"; 16, 17 and 18: indicate the side wall, piston and seal respectively of the above mentioned compressed air cylinder; 7 : indicates a bolt acting as a piston rod 17 put under tension at the time of clamping; 15, 19 and 20: indicate cylindrical ducts for supply of the compressed air cylinder chamber with compressed gas; 21 and 22: indicate 0-ring type seals for compressed air cylinder tightness; 23 : indicates a locking tooth for the punch to prevent its falling upon unclamping; and 24 : indicates a tooth with head shaped with an inclined plane and bed supported by a spring ring to cause the punch to complete at the moment of clamping a small upward traverse from the position hung on the hook 23 to the position resting against the horizontal lower face of the plate 3.2. FIG 4 shows in addition the construction details of the actuators of the jaw 6 and of the supply system thereof. FIG 4 and FIG 7 show that the form of the piston and chamber of the actuators for the jaws 6 (e.g. piston 17 of the actuator A6 of FIG 7) is similar to that of the pistons and chamber of the actuators for the jaw 8. Indeed, again in this case the piston seen from the front has a rounded rectangular shape at the minor sides and is traversed by two bolts acting as piston rods with the tip of each bolt screwed into the piston and the body traversing the two plates of the extension and the head inserted in a cavity of the jaw as shown in the example of FIG 7 (bolt 7). In this case the cylinder chamber side wall runs near the edges of the lower plate of the extension and is fixed thereto by four bolts located at the four corners of the wall. Supply of the actuators of the jaw 6 is also quite similar to that of the jaw 8 excepting a few differences. Indeed, the supply inlet on the left (and/or right) end of the module row and the supply passage from one module to the next are still as in FIGS 8 and 9 with the difference that in this case the inlets are for an extension. In addition, while for the supply passage from one module to the other of the row of jaws 8 a total length of the tube 94 approximately double that shown in FIG 9 is sufficient (the modules being near one another), in the case in question the tube 94 is longer, as shown in FIG 4. The reason for this greater length of the tubes 94 is that when providing the coupling between the tube and the duct inside the module as shown in FIG 9 the tube is exposed to running with air tightness within the duct, thus allowing, before clamping, bringing any two modules as near together as possible or spacing them, depending on the requirements of the current processing. By choosing e.g. for the tubes 94 a length approximately 95% the width of an extension, two successive extensions can be located apart up to a distance of approximately 75% of the width of an extension. With reference to FIG 9, this maximum spacing occurs when on both sides of the tube the slight flaring of the ends of the tube 94 is brought into contact with the internal ring 91. This option of spacing the extensions thus permits setting up different work stations on the front of the press. Die clamping jaws FIGS 5 and 6 show an embodiment of the die clamping system in accordance with the present invention while the lower part of FIG 7 shows a cross section view of this system along plane of cut CC of the above mentioned FIGS. In these figures the meaning of the various parts is as follows: 11: indicates the support bar of the die 2; 26 and 27: indicate locator elements to ensure correct positioning of the die on the support bar; and 28 and 29: indicate plates for clamping the locators against the sides of the die and of which the plate 28 is fastened permanently to the bar 11 and the plate 29 is clamped against the locator 27 on command of the actuator A29. The system of supplying the actuator A29 is quite similar to that of the actuator of the plate 8'' excepting a different shaping of the bush 30 around the bolt 31 (with respect to the bush 33 around the bolt 9) and the presence of the annular seal 32. FIGS 10a, 10b and 10c show another embodiment of the extension and of the lower compressed air cylinder actuator (for clamping the punch spigot). This is useful if it is desired to allow a double option of installation of the punch in the press, i.e. the option of installing the punch of FIG 7 with the concave surface facing right (as in FIG 7) or with the concave surface facing left. In particular, FIG 10a is a cross section view through the axis of one of the two bolts 71 acting as the compressed air cylinder piston rods. FIG 10b is a cross section view of the lower actuator through the axis of the duct 72 for supply of the cylinder chamber and through the axis of a spring 73 for release of the right-hand jaw. FIG 10c is a cross section view of the actuator through the axis of a bolt 74 for seal of the righthand jaw and through the axis of a spring 75 for release of the lefthand jaw. As may be seen by comparing the figures the main differences of the solution of FIGS 10a to 10b with respect to that of FIG 7 are as follows: the plate 76 of the extension on which rests the punch displays an L-shaped cross section with the thickness of the upper part of the plate increased with respect to the thickness of the lower part by an amount approximately equal to the thickness of the punch spigot; the lower actuator is also provided like the upper actuator (see FIG 7), i.e. with the bottom plate 77 of the compressed air cylinder chamber also acting as a clamping jaw; and the cylinder chamber supply duct is provided in its end part by a tube 78 running sealed with in a hole present on the bottom of the cylinder chamber. The operation of the lower actuator can be described as follows. When punch clamping is commanded by sending of pressurized gas into the cylinder chamber one jaw of the lower actuator clamps against the punch spigot (whether the punch is positioned as indicated by solid lines as in FIG 10a or as indicated by broken lines in the same figure) while the other clamps against the extension. When unclamping is commanded (supply gas no longer pressurized) the release springs command withdrawal of the jaws from the surfaces on which they were clamped so as to allow punch changing or moving. Reference is now made to preferred embodiments of some components of the compressed air system described above. Tubes inserted in a running manner in the extensions These tubes can be constructed advantageously of stainless steel or chromiumplated iron so as to avoid oxidation of their outer surface and thus ensure lasting seal of the seals on which they run. Compressed air cylinder side walls Considering the low pressures used these side walls can be provided economically in diecast aluminum monobloc form. Opening of the punch clamping jaws It is appropriate to provide springs, inserted partly in specially provided cavities and partly in opposing cavities present in the extension, which compress in clamping and, when the actuators are deenergized, cause automatic withdrawal of the jaws from the punch spigots. The advantages of the embodiment of the present invention are clear and are as follows: total absence of supply tubes along the front of the press to allow additional useful working space; the option of using low pressure compressed air with simplification of problems of hydraulic seal and distribution and manufacture of the various components and in particular of the cylinder walls, also by reason of the sizing of the cylinder chambers; and low cost of conversion to the new system of manual clamping machines. It is clear that numerous modifications can be made to the embodiments described above by way of nonlimiting example without thereby going beyond the protective scope of the following claims. On this matter it is observed that the particular supply system of the modules as shown in FIG 9 (with optional running of the compressed gas supply tubes within the module cavities) is essential only for the extensions because the modules of the upper row (extension clamping jaws) and those of the lower row (die clamping jaws) are installed permanently sidebyside with no possibility of running.

Claims: Press with a system for clamping or unclamping cornice brake tools, in which are present rows of punches (1), dies (2) and modular units constituting extensions (3") of punches and clamping jaws (6, 8) for said punches (1) and extensions (3"), characterized in that: clamping of the jaws (6) which clamp each punch modular (1) unit to the overlying corresponding extension modular unit (3"), takes place through bolts (7) put in tension by means of compressed air cylinder actuators (A6); supply of the compressed air cylinders of the actuators (A6) takes place through ducts (14, 15) made inside the body of the jaws (8) and/or said extensions (3") and through tubes (94) running between jaws and/or said extensions (3") of each side-by-side pair; and the tubes (94) running between said extensions (3") are metal tubes with straight horizontal axis partly running between extensions (3") of each side-by-side pair and partly inserted in cavities made in the sides of said extensions with the capability of free airtight running within said cavities, whereby a variation in spacing of the extensions (3") is thereby enabled. Press in accordance with claim 1 characterized in that die clamping takes place within pairs of locators (26, 27) locking the dies in correct position on the associated support bars (11) and is performed by means of clamping jaws (28, 29) with modular structure and compressed air actuators (A29) acting on the clamping jaws (28, 29) and supplied through channels made in the clamping jaws as well as through metal tubes running between the jaws of each side-by-side pair thereof to connect together the channels of the jaws of the pair. Press in accordance with claim 1 characterized in that the tubes running between the extensions (3") are made of stainless steel or chromiumplated iron. Press in accordance with claim 1 characterized in that the compressed air cylinder chambers display a vertical cross section having a surface area of the same order of magnitude as the surface area of the clamping jaws to which they are opposed. Press in accordance with claim 4 characterized in that the compressed air cylinder chamber side wall is provided by a die-cast aluminum monobloc.

Inventors: GIANELLI GIUSEPPE VITTORIO, GIANELLI, GIUSEPPE VITTORIO
Applicants: ABIEMME SRL, ABIEMME S.R.L.
Application year: 1996
Main classification: B21D5
IPC codes: B21D5