MXPA97008141A - Machine troquelad - Google Patents

Abstract

The present invention relates to a punching machine having a ram supported by a column and cantilevered frontally on a work surface, comprising a frame constituted by a column to which an arm is articulated, orthogonally oriented with respect thereto the direction of the piston, and a means cooperating with a pump motor unit of the machine, for the automatic determination of the end point of the ram, the machine is characterized because: a) the means for the automatic determination of the point of The tamper stroke end is formed to adjust the pressure exerted by the ram on a punch placed on a projection, b) the medium cooperates with one or more electrical contacts and is oriented vertically with respect to the work or cutting surface, or with with respect to the arm c) the medium is directly connected and fixed on the ram, and d) the medium is placed in correspondence with the portion of the median of the cutting surface or of the surface

Description

PITCHER MACHINE Description of the invention The present invention relates to a punching machine. More particularly, the present invention relates to a punching machine provided with a stroke end of a ram positioned in correspondence of the area defined by the cutting plane and connected by means of a frame to the base of the same machine. As is known, punching machines are used in various fields, among which the footwear industry, to carry out skin cutting operations, leather or synthetic materials and to obtain artifacts differently; The latter, for example, soles, arches, and tops, are then assembled together and subjected to additional work to obtain the finished product. The components or semi-finished products are obtained from leather, leather or synthetic materials by means of specially formed dies, composed of templates or metal models of the same height with cutting edges, on which a tamper acts; the pressure exerted by the latter on the dies, superimposed on the material to be cut, allows obtaining the different semi-finished products. During the punching operation several factors must be taken into account, such as the linear advance of the dies and the thickness, as well as the density or compactness of the material to be cut; in effect, the pressure which the tamper must exert is correlated with these variables. The punching machines of the known technique are provided, for this purpose, with a regulation system that allows to change, if necessary, by means of delays or electrical shifts manipulated manually, the pressure of the plunger; in fact, a longer period of time REF: 25951 of the activation of the hydraulic system that controls the fall of the arm is transformed into a greater pressure exerted by the arm on the dies and from here on the material to be cut. By changing the linear feed of the dies, the operator can therefore increase or reduce the pressure by operating special knobs which determine such delays or electrical delays, by means of microswitches that prolong or reduce the opening time of the circuit connected to the motor pump of the machine. In addition, dies of the known art are conventionally provided with tamper end devices, generally positioned on the back of the ram, in correspondence of or near its support column; The end-of-stroke device has the function of limiting the movement of the tamper to a level sufficient to cause the die to pass completely through the material, to obtain the semi-finished product of skin, leather or synthetic material. The many dies used have the same height and the regulation of the end of the stroke is made by placing one of the dies on the work surface or support; In this way, the exact point of the end of the race is established. Due to these basic characteristics, die cutters of the known art have some serious disadvantages. In effect, during the punching operations, the cantilever ram of the machine tends to deflect, to cause the anticipated interposition of the end of the stroke and the consequent incomplete cutting of the material; in these conditions, the operator must therefore manually activate the electrical delays based on his personal experience, with the danger of giving too much power and risk in a short time the work surface or support due to the indentations caused by the cutting edge of the dies The premature deterioration of the work surface or support, generally made of polypropylene, nylon or polyethylene, can also happen for another reason, correlated with the functionality of the stamping machines of the known art. When replacing a die that has a reduced linear feed with one that has a longer linear feed, the operator must adjust the machine with an appropriate electrical delay to give the ram the necessary pressure for a precise and complete cut of the material. On the contrary, in order to use again a reduced linear feed die, the operator must reduce the pressure of the arm by actuating again on the knobs controlling the electrical delays.; since the dies necessary to obtain the different parts of an artifact, for example a shoe, are numerous and of different shape and size and are used alternatively on the same skin, the operator must continuously change the electrical delays. In practice, this does not happen, especially since such continuous regulations would require high production times; consequently, the operator tends to regulate the pressure of the ram according to the die having a longer linear advance and to adhere to this adjustment also when using smaller punches. As a consequence, the support is excessively indented and therefore requires frequent rectifications and replacements. In another known type of punching machine, the end of stroke comprises lever devices; however, these systems are not precise due to the inevitable separations that are present between the elements that form the various levers. The object of this invention is to eliminate the above disadvantages.

More particularly, the object of this invention is to provide a punching machine in such a way that it does not require continuous pressure adjustments of the rammer when changing the dies used. A further object of this invention is to provide a punching machine wherein the regulation of the end of stroke of the plunger is not affected by the deviations to which the plunger is subjected during the punching. A further object of the invention is to provide users with a punching machine that ensures a high degree of strength and reliability over time and also in such a way that it is easy and economically feasible. These and still other objects are obtained by the punching machine of this invention, with a ram supported by a column controlled at the base and cantilevered on the front part to the work surface, provided generally with a support, comprising a frame rigidly joined with one end to the same base, the frame is composed of a column, to which an arm is articulated, orthogonally oriented with respect to it in the direction of the ram, which carries means cooperating with one or more contacts electrical units connected to the machine's pump unit, integral with the upper front part of the ram, for the automatic determination of its end-of-stroke point and the pressure exerted on the die placed on the support. The construction and structural features of the punching machine of this invention will be better understood thanks to the following description, wherein reference is made to the accompanying drawings which represent a preferred non-limiting embodiment and wherein: Figure 1 shows schematically the partial side view of the punching machine of the invention; Figure 2 schematically shows a partial front view of the same punching machine. With reference to the drawings, the punching machine of the present invention, indicated as a whole by 10 in FIG. 1, basically consists of a base 12 that carries a workpiece holder and cutting and working surface 14, with a support 16 and a ram 18 supported by a column 20 controlled on the same base and moved vertically by a hydraulic motor pump unit (not shown). Between the back side of the work surface 14 and the part of the base where the column 20 is inserted and slides, a conventional housing 22 extends transversely, which collects the skin or the material of which the semi-finished products of Various shapes and sizes are obtained by die cutting. According to the invention, the punching machine 10 is advantageously provided with a frame, partially fixed and partially articulated, which carries means for the precise and automatic determination of the end-of-stroke point in the vertical direction and the pressure of the rammer 18 which press the dies from which the semi-finished products are obtained. Such a frame is constituted, according to a preferred non-critical embodiment, of a support column 24, whose lower end is rigidly joined to the rear side of the machine 10 where the column 20 slides and by means of an arm 26 which advances from the opposite upper end of the same column 24, orthogonally oriented with respect thereto in the direction of the ram 18. The arm 26 is articulated on an extension 24 'of the column 24 by means of a conventional bolt 28 provided with ball bearings Opposites 30 or the like. The arm 26, to which a total or partial cover 32 is preferably associated, advances towards the front of the punching machine 10, that is, in the direction of the point where the operator determines the positioning of the punch 18 on the surface of the punching machine. working or cutting 14, by means of a conventional handle 34 located near the front end of the arm. The longitudinal extension of the arm 26 is advantageously limited to such a level as to superimpose its end on the forward part of the tamper 18., that is, on the zone substantially corresponding to the middle front portion of the cutting surface 14 and the related support 16, which portion is pressed in any way or defined by its shortest side. The arm 26 and the cover 32 are hingedly connected to the underlying ram 18 by means of a bolt 36 or similar means, attached to the fastening means, such as, for example, the nuts 38; the pin 36 is located, by way of example, in correspondence with the back part of the ram 18, before the bolt 28 which joins the arm 26 to the extension 24 '. The front end of the arm 26 and the cover 32 house the means that determine in a precise and automatic way the cutting of the material, independently of its thickness and / or density and the type of die used. The means, indicated generally by 40, are partially housed in the arm 26 and the cover 32 and partially cause them to be integral with the upper front part, indicated by 18 ', of the tamper 18. A rod 42 is slidably received inside. of the cover 32 and the arm 26, from the bottom of which comes out, to be brought into contact at the lower end with a round nut 44 or the like, provided with a central through hole; on the part of the rod 42 projecting from the arm 26 a spring 46 is adjusted. The through hole obtained on the round nut 44 has an increase in diameter at the end, to define a housing 48 suitable for housing a mechanism that prevents the rod 42 from coming out of the round nut; the mechanism is constituted, by way of example, of a seeger ring 50, located in a throat or narrowing formed in a position near the lower end of the rod 42. In the upper part of the same rod which advances to the cover 32, by on the arm 26, a ring is fitted on which the arm 26 is attached, at the moment when the ram 18 is lowered or lowered, as specified below in relation to the operation of the punching machine 10. Ring 52 it is positionable at different heights along the stem 42 by means of a conventional knob 54, located externally in relation to the cover 32, the stem 56 of which goes radially through the ring 52 and abuts the same rod. Advantageously, in the final part of the rod 42, above the ring 52, a spring 58 is adjusted, delimited on the opposite front part by a cover 60 joined to the rod by means already known, near its upper end portion. In alignment with the round nut 18, to the upper front part 18 'of the ram 18, a support 62 for an electrical contact is connected, for example a micro-switch 64 or the like, which acts on the circuit connected to the motor-pump of the die cutting machine 10; the microswitch is driven by the round nut 44. During the punching operation, the ram 18 falls in the direction of the support 17 of the work surface 14 on which the material to be cut is placed, on top of which the die: the fall of the ram 18 is followed by that of the rod 42, caused by the extension of the spring 46, fitted on the rod and located between the round nut 44 and the lower front part of the arm 26. Ring 52, attached to the rod 42, it descends until it reaches the stop point formed by the upper front part of the arm 26; in this condition, the ram 18 joins its base with the die positioned on the material to be cut. During the aforementioned descent step, the round nut 44 acts systematically on the electrical contact or microswitch 64, to keep the circuit connected to the motor pump of the punching machine 10 open; once in contact with the die, the ram 18 must reach its end of stroke, to carry out an additional descent, for a limited extension, equal to the thickness of the material to be cut. In this final step, the pressure exerted on the die by the ram 18 must be calibrated, that is, sufficiently to stand through and consequently cut the material, but not in excess, so as not to jeopardize the integrity of the support.; furthermore, in this stage it is necessary to compensate the deviations to which the tamper can be subjected at the moment in which it presses the die and the underlying material. The optimization of the operation stage is carried out thanks to the activation and deactivation system of the electrical contact or microswitch 64, as it is configured and arranged according to this invention.; in effect, the round nut 44 keeps the circuit connected to the power unit systematically open, as it is driven downwards by the spring 46 fitted on the bottom of the rod 42. Possible deviations of the ram 18, which tends to rise orienting angularly backward, they determine the extensions of the opening times of the circuit, since the electrical contact or microswitch 64 is always open by means of the exceptional round nut 44. At the moment when the tamper 18 has overcome the resistance of the material, it has led to the lower edge of the die to join the stop to the support 16, to thereby reach the limit stop, the support 62 of the electrical contact or micro-switch 64 is removed from it. the round nut 44, which allows the contact to open and interrupt the flow of energy or pressure of the circuit of the motor pump unit of the punching machine 10. Therefore, the circuit remains open until the moment when the plunger has fallen completely to indent and cut the material, regardless of the thickness and density of it. The compensation of pressure that the tamper must exert is therefore automatic, correlated with the time necessary to carry out the punching, since its end of stroke is not perceived on the support 16 of the work surface 14, but on the same tamper 18; therefore, no approximate manual adjustment of the electrical energy correlated with the pressure is necessary and at the same time the danger of partial cutting of the material is avoided, since the deviations of the ram 18 are irrelevant. The dies that have a different linear advance, the materials with a greater or lesser density and / or thickness, are therefore not conditioning factors for the purpose of obtaining a complete and precise die cutting. The electrical contact 64, being directly in contact with the tamper 18, ensures the optimum working accuracy of the end-of-stroke device and therefore the separations of the connection means or switching ratio of the microswitch are excluded. It is worth noting that the movement of the ram 18, with respect to the orientation relative to the working surface 14 and the underlying support 16, is carried out according to conventional systems, the ram is orientable by virtue of the articulation formed on the extension 24 'of the column 24 and thanks to the bolt 36. However, the invention, as described above and claimed later herein, has been proposed only by way of example, since it is susceptible to many changes and variants, which fall in any way within the scope of the inventive concept. For example, the electrical contact or microswitch 64 and the associated activation means could be located in a different position on or in correspondence with the ram 18, preferably at any point of its middle frontal part. A different position of two or more electrical contacts - which are not necessarily constituted by microswitches - can also be taken into account with the related means for their contemporary or sequential activation and / or the creation of two articulated arms that protrude from one or more integral columns with the base of the die-cutter. The activation of the two electrical contacts can also be obtained by means other than the round nut described above and / or the rod to which the round nut is attached. Finally, structural inversions or alternative positions of the components of the parts forming the whole stamping machine of this invention as a whole are possible.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following

Claims (9)

1. Claims 1. A punching machine, with a ram supported by a column controlled at the base and cantilevered frontally on the work surface, which is generally provided with a support, characterized in that it comprises a frame rigidly attached to one end of the base , constituted by a column to which an arm is articulated, oriented orthogonally with respect thereto in the direction of the ram, carrier means cooperating with one or more electrical contacts connected to the motor pump unit of the machine, integral with the part upper front of the ram, for the automatic determination of its end of stroke point and the pressure exerted on a die placed on the support.
2. 2. The punching machine according to claim 1, characterized in that the means cooperating with the electrical contacts are constituted by a rod, which is placed in a sliding manner and is driven in the front part of the arm, from which it protrudes to come into contact with a round nut or the like, provided with a through hole, which has a larger diameter at its end and defines a housing for a ring fastened to the end of the rod, a spring which is butted on the upper part of the ram and in the lower part the round nut fits over the part of the rod protruding from the arm.
3. 3. The punching machine according to claims 1 and 2, characterized in that the rod advances above the arm to a cover which incorporates all or part of the tamper and carries a ring slidably positionable thereon by means of a knob, whose The rod advances radially through the ring.
4. 4. The punching machine according to any of the preceding claims, characterized in that a lid is fastened above the ring, near the upper end of the rod, a spring is located between the lid and the ring.
5. 5. The punching machine according to any of the preceding claims, characterized in that the rod projecting from the arm is oriented vertically in relation to the work surface or cut and is placed in correspondence with the defined area by the shortest side of the surface.
6. 6. The punching machine according to any of the preceding claims, characterized in that a support for the electrical contact is attached to the upper front part of the ram and in correspondence with the round nut of the rod.
7. 7. The punching machine according to any of the preceding claims, characterized in that the round nut moves progressively away from the micro-switch, in correspondence with the starting point of the material cut by means of the punch pressed by the rammer, the round nut of the rod it joins butt on the upper front part of the arm.
8. 8. The punching machine according to any of the preceding claims, characterized in that the ram is articulated on an extension of the column by means of a bolt provided with opposite bearing balls or the like.
9. 9. The punching machine according to any of the preceding claims, characterized in that an arm and a cover are joined in an articulated manner to the underlying rammer by means of a bolt or the like, fastened with nuts.