MXPA97009073A - Zero force roller relay for high speed press feed units - Google Patents

Abstract

The present invention relates to an apparatus for the intermittent feeding of metal working parts to a press, the apparatus comprises: a feed roll, a clamp roll opposite said feed roll allowing the metal work pieces to pass between said rolls a driving mechanism for driving said feed roller, and a clamping roller actuator connected to said clamping roller, such that said clamping roller is oriented to the metal working parts passing between said rollers, said clamping roller actuator selectively interchangeable towards and far from said fastener roller during the operation of the apparatus, said roller actuator modifies the pressure developed by the roller between said clamping roller and the metal workpiece without causing the loss of contact between said clamping roller and the metal workpiece

Description

ZERO FORCE ROLL RELAY FOR HIGH-SPEED PRESSURE FEED UNITS BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to an apparatus for the intermittent feeding of raw material to a press, such as those of the type used for engraving and stretching. 2. DESCRIPTION OF THE RELATED ART There are numerous types of press feeding mechanisms available in the market, each of which has certain advantages and disadvantages, depending on the specific application. For example, those that have a mechanism of type bed of feeding which has elements with characteristics of high performance, usually previous flexibility as in the case of machines of type servo. The feeding mechanism for servo-type presses represents a greater ease of adjustment in exchange for sacrificing speed, such as in the case of a feeding bed mechanism. The new electronic high speed roller feed mechanisms provide moderate speed profiles as well as high speed features along with flexibility. The aforementioned high speed bed, servo, and electronic feeder devices use different configurations to provide a clean and accurate lift of the fastener roller. The clamping roller moves from a maximum position of clamping and contact against the work piece, until reaching a position away from the contact with the work piece, creating what is known as lifting the roller. This lifting of the roller, if not precise and in synchrony with the release of the roller, can impede the proper operation of the matrix pilot pin. Furthermore, it is necessary that said devices allow the precise return of the clamping roller to its position of contact with the work piece in a controlled manner. The tapping of the press bra or roller against the work piece may cause the roller to bounce or, alternatively, deform said work piece. Conventional press feeding mechanisms have used a type of roller lifting in which the feeder has a clamping roller that moves to stop being in contact with the work piece, so that the press can control the work piece through the use of pilot pins to align the work piece inside the press. In other words, the fastener roller loses physical contact with the workpiece for a particular period of time during the course of the feed cycle. The previous systems were used to eliminate any errors in the placement that resulted from the feeding progress. The known feeding system includes a gear train that increases the rotational inertia of the system. In the technique it is necessary to have the capacity to exercise a more precise control of the work pieces that are handled at high speeds, by means of the use of a method of lifting the roller of greater speed. SUMMARY OF THE INVENTION A mechanism for feeding material for presses according to the present invention is described.

The clamping roller of the present invention is controlled so as to duarte the operation of the apparatus, the clamping roller does not lose contact with the work piece or raw material during the operation process, that is, the moderate clamping force between the roller The fastener and the work piece descend substantially to zero, thereby reducing the friction between them. In such a situation, the pilot pins of the engraving or associated drawing press can easily control the movement of the raw material or work piece. Zero force, as defined in the present patent application, is one in which the clamping force between the clamping roller and the material in the clamping position substantially reaches zero. Under this circumstance, the press will be able to control the work piece. An advantage of the present invention is that the lifting of the roller is substantially eliminated between the clamping roller and the workpiece, whereby the press feeding mechanism presents a much faster response in the corresponding cycles. Another advantage of the present invention is the use of a clamping roller actuator which causes the clamping roller to approach and move away from the work piece, without substantial movement being made. During the press feeding operation process, it is not necessary to create a roller lift, since the clamping roller actuator only modifies the clamping force between the clamping roller and the raw material. In other words, the clamping force is reduced substantially to zero, allowing the loss of contact between the clamping roller and the workpiece. Another advantage of the present invention is that the movement of the clamping roll is controlled so that the value of the displacement is practically zero at the time of clamping. Therefore, the result is a faster response to go from a clamping force equal to zero, to a maximum clamping force, since no substantial displacement of the clamping roller takes place, unless it is possible to do so. the compression of the work piece. By having a faster response, it is possible to obtain the corresponding increase in the output speed. Another advantage of the present invention is that through the use of the zero force method described above, no marks are present on the material, unlike what happens with conventional roller lifting mechanisms. Because no gap is created after the clamping roller pressure is released, there is also no opportunity for the clamping roller to suffer any impact that causes it to close (Rebound Roller Lift), or that comes in contact with the work piece during the application process of the maximum clamping force. This avoids generating any damage due to an impact on the roller or the workpiece. Another advantage of the present invention is the fact that when the maximum clamping forces are applied the vibration or rebound of the press is reduced. In the methods previously used in the art, the vibration was created at the moment when the pinch roller was close. By reducing the elevation of the aforementioned roller of the new system in accordance with the present invention, it is possible to eliminate any of the errors that could occur during the feeding process. One more of the advantages of the present invention is the use of a single belt drive system for rotating the feed device and the roller. Through the use of a double-sided distribution band, it is possible to eliminate the elements of the conventional gear train. Yet another of the advantages of the present invention is the use of a driven screw servo actuator. Said actuator allows greater control and a faster response of the fastener roller in comparison with the pneumatic or hydraulic actuators previously used. Another advantage of the present invention is the use of a support roll support on the feed roller of the device. This support roller increases the positioning precision and the control capacity of the feed roller. The present invention, in one of its embodiments, comprises an apparatus for the intermittent feeding of work pieces to a press. The apparatus includes a feed roll with a pinch roller opposite the feed roll and a work piece passing between both rolls. A drive mechanism that is used to drive the feed roller. A clamping roller actuator that is connected to the clamping roller so that during the operation of the clamp, the actuator changes the pressure of the clamping roller developed between the clamping roller itself and the work piece, without causing the loss of contact between the roller bra and work piece. The present invention, in another of its embodiments, comprises an apparatus for the intermittent feeding of work pieces to a press. The aforementioned apparatus includes a feed roll with a pinch roller which opposes said feed roll, and a work piece passing between both rolls. A drive mechanism that is used to drive the feed roller. A clamping roller actuator that is connected to the clamping roller so that during the operation of the clamp, the pressure developed against the workpiece ranges from being a maximum clamping force, to being a zero force. The present invention, in yet another of its embodiments, includes a method for controlling the fastening roller of a press feeding unit having a feed roller, and said method comprises the steps of supplying the work pieces between the fastening roller and the feed roller, the application of a force on the clamping roller to create a maximum clamping force between the clamping roller and the work piece to achieve the displacement of the work piece by means of the feed roller, and the release of the force previously created while the fastener roller is held in contact with the workpiece to cause said workpiece to be displaced by the press.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned characteristics, as well as other characteristics and advantages of the present invention, as well as the way to achieve them, will be clearer as the present invention will be better understood when referring to the following description of a embodiment of the present invention, together with the drawings appended thereto. Figure 1 is a sectional view of the present invention. Figure 2 is a sectional view of the device of Figure 1, taken along line 2-2, and viewed in the direction indicated by the arrows.

DETAILED DESCRIPTION OF THE PRESENT INVENTION Referring to the drawings, and in particular to Figure 1, there is shown an apparatus, generally designated with the number 10, for the feeding of work pieces such as raw material of continuous type coming from an apparatus unroller, to a mechanical press, in order to perform one of multiple pressing operations, such as, but not limited to, engraving, die cutting, cutting, inclusion coupling (sta ing), and similar operations. The apparatus 10 includes a compartment 12 for supporting the rest of the device. Within the compartment 12 there is a feed roller 14 attached to the feed roller shaft 16. A servo motor 18 (Figure 2) is the roller drive for the apparatus 10. Parallel and opposite the roller 14 is the clamping roller 20. The fastening roller 20 is placed on a clamping roller arrow 22. The clamping roller arrow 22 is positioned within a clamping roll holder 24, which contains both the clamping roller 20 and the clamping roller arrow 22, so they turn inside it. The feed roller 14 is connected to the servomotor 18 by means of the uninsured bearings 19 (Figure 2). This configuration results in the substantial elimination of the rotational inertia due to the elimination of a coupling element between the servomotor 18 (Figure 2) and the arrow of the feed roller 14 (Figure 1). In the present embodiment of the invention, the arrow of the servomotor is, in fact, the arrow of the feed roller 16. As shown in Figure 1 and Figure 2, behind the feed roller 14 are the optional support rollers 26, which increase the stability of the feed roller 14. The support rollers 26 are secured by sliding along the bottom 13 of the compartment 12. A rotating bolt 28 passes through each of the mounting elements of the roller. the support rollers 26, whereby adjustment and control of the feed roller 14 is allowed. These support rollers 26 cooperate in the rotary support of the feed roller 14. The support of the fastener roll 24 is made of machined steel, and acts as a support for the fastener roller. Additionally, the clamping roll holder 24 is secured by the approaching and moving movement, in the normal direction, relative to the workpiece and the raw material platform 35. As shown in Figure 1, a clamping roller servo actuator 30 is connected to control and move the clamping roll holder 24, bringing it closer and further away from the feed roller 14. In addition to the foregoing, and more important for the present invention, the actuator 30 generates and controls the clamping force of the roller 20 fastener over the work force. During the operation process, the servo actuator of the clamping roller only modifies the clamping force between the clamping roller 20 and the work piece, instead of raising the clamping roller 20 away from the work piece. The roller screw servo actuator 30, operates with electric current, so that the force generated and applied on the clamping roller 20, and by means of this to the work piece, is proportional to the electric current that is applied. Said actuator 30 is not a device based on the position, but based on the force, since its position depends on the current of electric power supplied to it together with certain forces (gravity, etc.), or opposing forces (support of the material or interference). The transmission of the rotation is caused by a distribution band 32, which extends from the tension pulley 34 which is on the roller support 24, passes over the feed roller 16, behind the roller of fastener roller 22, and goes up again to the pulley 24. The distribution bands 32 have double-sided, and the bands with double teeth are capable of transmitting the rotation force from the drive element (servomotor 18), to the rollers 14 and 20 As shown in Figure 2, two of said distribution bands 32 are used on each side of the apparatus 10.

The material intake platform 36 (part of the raw material platform 35), together with the guiding element of the work piece 37, are used to guide the work pieces towards the device 10. The material exit platform premium 38 (second part of the raw material platform 35), guides the work pieces in production towards an associated press (not shown). As shown in the Figure 2, at least two eccentric type belt tensioners 40, are used in place of the pulley 24, in order to anneal the distribution band 32.

A mechanical or electronic control mechanism, in combination with the press (not shown), correctly operates the motor 18 and the clamping roller servo 30 in synchrony with the operation of the press. An adjustment mechanism is connected to the control mechanism to correctly control the electric current that is applied to the actuator 30. During its operation, the present invention causes the fastening roller 20 not to separate from any of the moving workpieces. through the device 10, when the clamping force is released. The raw material of the work piece slides through the raw material intake platform, by means of the raw material guide elements 37, and comes into contact with the feed roller 14 and the clamping roller 20. The servomotor 18 drives the feed roller 14 in a series of ascending steps, as necessary for the feeding of the raw material in the press (not shown), during the development of the feeding process. To ensure proper alignment of the fed material passing through the device 10 and along the material exit platform 38, the clamping force between the clamping roller 20 and the work piece, or alternatively, the existing force between the clamping roller 20 and the feed roller 14, it will be substantially reduced to zero, by means of a reduction in the force created by the actuator of the clamping roller 30 shown in Figure 1. The actuator 30 produces a reduction in the maximum clamping force existing between the clamping roller 20 and the workpiece, which allows the workpiece to pass along the material exit platform 38 to be displaced, slid, or guided, by the pilot pins within of the operation process of the tool (not shown). During another cycle, or a subsequent work cycle, when it is necessary for a greater amount of material to be fed to the press, the actuator 30 will cause the clamping roller 20 to modify its current state of clamping force substantially to zero, to a state of maximum clamping force generated between the clamping roller 20 and the work piece. It is at this time that the maximum current is applied to the servomotor 18, in which the workpiece is driven and slid, coming from the raw material intake platform 36, towards the material exit platform 38. After that this part of the cycle has been completed, the actuator 30 will again reduce the clamping force exerted between the clamping roller 20 and the work piece, until it reaches a value substantially of zero. Although the clamping force generated by the actuator ranges from a maximum clamping force value to a clamping force value equal to zero (as defined in the present application), the current applied to the actuator 30 may not necessarily be decreased to a value of zero. It may be necessary, or desirable in some embodiments, to produce a very small tensile force between the fastener roller 20 and the workpiece. Even in this case, the clamping roll will not be lifted or lifted away from the work piece by the actuator 30.

Claims (10)

1. CLAIMS 1. An apparatus for the intermittent feeding of workpieces to a press, which comprises the following: A feeding roller. A fastener roller opposite the feed roller, and a work piece passing between said rollers. A drive to drive the feed roller. A clamping roller actuator that is connected to said clamping roller, which modifies the pressure developed by the clamping roller itself clamping roller and the work piece during operation of the apparatus, without causing the loss of contact between the aforementioned clamping roller and the work piece.
2. 2. An apparatus according to claim 1, wherein said clamping roller actuator controls the pressure of the clamping roller from a maximum clamping force to a force of zero value.
3. 3. An apparatus according to claim 1, wherein the aforementioned clamping roller actuator controls the pressure of the clamping roller proportionally to the electric current applied to said actuator.
4. 4. An apparatus according to claim 1, wherein the drive comprises an electric motor that is attached to the feed roller by means of uninsured bearings.
5. The apparatus claimed in claim 1, wherein the driving mechanism comprises a belt drive including a timing belt that is connected to said feed roll, and an electric motor secured to said feed roll by means of of bearings without insurance.
6. 6. An apparatus according to claim 1, which also comprises a support roller to rotationally support the operation of the aforementioned feed roller.
7. 7. A method for controlling a pinch roller in a press feed unit, which has a feed roll, and said method comprises the following steps: Supply of a work piece that is between the pinch roller and the pin above mentioned feeding. The application of a force on said clamping roller in order to generate a maximum clamping force between said clamping roller and the work piece, so that said work piece is moved by the aforementioned feeding roller. The release of the previously generated force while holding said fastener roller in contact with the work piece, in order to cause the work piece to be displaced by the press.
8. 8. An apparatus for the intermittent feeding of workpieces to a press, which comprises the following: A feed roller. A fastener roller opposite the feed roller, and a work piece passing between said rollers. A mechanism of driving bands to drive the feed roller. A clamping roller actuator that is connected to said clamping roller, which modifies the pressure developed between said clamping roller and the work piece during operation of the apparatus.
9. 9. An apparatus according to claim 8, wherein the web drive includes a double-sided double-sided distribution band, which is connected in a drive configuration with the roller. feeding and the aforementioned fastener roller.
10. 10. An apparatus according to claim 8, wherein the aforementioned clamping roller actuator controls the pressure of the clamping roller proportionally to the electric current applied to said actuator.