Movement mechanism with independent motors for the blade holder unit of panel bender machine

Abstract

A bender machine designed to bend and shape sheet metal comprising a blade holder unit (1) which has a “C” shaped section, which is mobile and moves in two directions, both of which are at right angles to a fixed bench, and where the unit is fitted with one or more bending blades, wherein: servomotors and planetary gear reducers are used for moving the blade holder unit (1);
the blade holder unit (1) uses a jointed mechanism comprising two mechanical units (20, 20a; 30, 30a) which form a closed kinematic chain of five components connected by five kinematic pairs all of which are revolute; the mechanical unit (20, 20a) for moving the blade holder unit (1) in a substantially vertical direction comprises a pair of servomotors coupled respectively to two gear reducers, which operate respective cranks (9, 9a) on which respective connecting rods (8, 8a) are hinged, and where the other end of each connecting rod is connected by respective pins (7, 7a) to a respective base (10, 10a) fixed to the blade holder unit (1). The mechanical unit (30, 30a) for moving the blade holder unit (1) in a substantially horizontal direction comprises one pair of servomotors (6, 6a) coupled to corresponding planetary gear reducers, each of which operates a respective camshaft (3, 3a), and also characterized in that the camshafts (3, 3a) are hinged on the rear supports (2, 2a) of the blade holder unit (1).

Claims

1. A kinematic system for actuating a work unit of a bender machine designed to bend and shape sheet metal, wherein the bender machine comprises a blade holder unit having a “C” shaped section, wherein the blade holder unit is mobile and moves in two directions, wherein one of the two directions comprises a substantially horizontal direction with respect to a fixed bench and wherein another of the two directions comprises a substantially vertical direction with respect to the fixed bench, and wherein the blade holder unit comprises one or more bending blades, wherein the kinematic system comprises: a first mechanical unit wherein the first mechanical unit moves the blade holder unit in the substantially vertical direction with respect to the fixed bench; the first mechanical unit comprising a first pair of servomotors coupled to a corresponding pair of gear reducers, wherein each of the servomotors in conjunction with the corresponding gear reducers are coupled to and operate respective cranks, wherein a connecting rod is hinged to each of the cranks, and wherein the other end of each connecting rod is connected to a base fixed to the blade holder unit by respective pins; and a second mechanical unit, wherein the second mechanical unit moves the blade holder unit in the substantially horizontal direction with respect to the fixed bench; the second mechanical unit comprising a second pair of servomotors coupled to a corresponding pair of planetary gear reducers, wherein each of the servomotors in conjunction with the corresponding planetary gear reducers are coupled to and operate respective camshafts, and wherein the rear supports of the blade holder unit are hinged on the respective camshafts and wherein the respective camshafts act as rotation pins for a tilting movement of the blade holder unit and as a crankshaft which generates the substantially horizontal movement of the blade holder unit.

2. The kinematic system according to claim 1, wherein the substantially vertical direction movement and the substantially horizontal direction movement implemented respectively by the first and second mechanical units are independent and different from each other.

3. A bender machine designed to bend and shape sheet metal, comprising a blade holder unit having a “C” shaped section, wherein the blade holder unit which is mobile and moves in two directions, wherein one of the two directions comprises a substantially horizontal direction with respect to a fixed bench and wherein another of the two directions comprises a substantially vertical direction with respect to the fixed bench, and wherein the blade holder unit comprises one or more bending blades.

4. The bending machine according to claim 3, wherein the movement of the blade holder unit is driven by servomotors and planetary gear reducers, and wherein the blade holder unit uses a jointed mechanism comprising two mechanical units which form a closed kinematic chain of five components connected by five kinematic pairs all of which are revolute.

5. The bending machine according to claim 4, wherein the two mechanical units implement trajectories which are independent and different from each other.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention is described below with reference to the attached drawings, provided as a non-binding example, in which:

(2) FIG. 1 shows a rear perspective view of the “C” shaped blade holder unit of a panel bender according to the present invention;

(3) FIG. 2 shows the same rear perspective view of the blade holder unit as in FIG. 1, but also showing the movements performed by the various components.

(4) FIG. 3 is a vector diagram showing the movements performed by the blade holder unit with the kinematic architecture shown in FIG. 1.

DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

(5) FIG. 1 shows a panel bender for bending sheet metal sheets comprising a “C” shaped blade holder 1 to which a pair of blades comprising a lower blade 4 and an upper blade 5 are fixed. The blade holder unit 1 is moved by servomotors and planetary gear reducers as described in greater detail below.

(6) The rear part of the blade holder unit structure comprises a fixed pair of supports or expansions 2, 2a while the lower part is fitted with bases 10, 10a. The supports 2, 2a and the bases 10, 10a are actuated by a special kinematic system whose chain has two effective degrees of freedom and forming two mechanical units one of which 30, 30a is designed to move the blade holder unit 1 in an approximately horizontal direction and where the other 20, 20a is designed to move the blade holder unit 1 in an approximately vertical direction.

(7) The jointed system comprising the entire mechanism is kinematically considered to be a flat mechanism where the term flat mechanism is understood as describing a mechanism whose components move on a flat plane with the axes of the revolute pairs parallel to each other and at right angles to the flat plane of motion.

(8) The topology of the system, the number of its components and the type of coupling makes this a closed kinematic chain of five components connected by five kinematic pairs all of which are revolute.

(9) One of the components is the machine frame. This kinematic chain has two effective degrees of freedom which enable the use of two independent servomotors each installed on its respective mechanical unit.

(10) According to the present invention, the first mechanical unit comprises one pair of respective servomotors 6, 6a coupled to corresponding planetary gear reducers, each of which operates a camshaft 3, 3a on which the supports 2, 2a of the blade holder unit 1 are hinged.

(11) The camshafts 3, 3a have two different functions. They act as rotation pins for the tilting movement of the blade holder unit 1 and at the same time also act as a crankshaft which generates the approximately horizontal movement of the blade holder unit 1.

(12) The second mechanical unit 20, 20a comprises a pair of servomotors coupled respectively to two gear reducers which operate respective cranks 9, 9a on which connecting rods 8, 8a are hinged, and where the other end of each connecting rod is connected by respective pins 7, 7a to a base 10, 10a of the blade holder unit 1.

(13) The geometry of the mechanism: has the work space necessary for efficiently moving the bending blades in the field of application envisaged; has the special geometrical configurations, (for the single kinematic conditions where there is kinematic inversion of motion) around the configurations where the mechanism bends the sheet of metal, needed to generate the necessary amplification of the drive torques. There are two configurations, one for the ‘positive bend’ and one for the ‘negative bend’.

(14) FIGS. 2 and 3 show the link trajectories where the Z references indicate the following kinematic connections: Z1—crank 9 of the first link between the motor and the connecting rod 8; Z1a—crank 9a of the second link between the motor and the connecting rod 8a; Z2—trajectory of the connecting rod 8 of the first link; Z2a—trajectory of the connecting rod 8a of the second link; Z3—trajectory of the first link between the hinge of the connecting rod 8 and the blade holder unit 1, and hinge 6 of the camshaft 3; Z3a—trajectory of the second link between the hinge of the connecting rod 8a and the blade holder unit 1, and hinge 6a of the camshaft 3a; Z4—movement of the camshaft 3 of the first link between the motor and the rear expansion 2 of the blade holder unit 1; Z4a—movement of the camshaft 3a of the first link between the motor and the rear expansion 2a of the blade holder unit 1.

(15) In particular the trajectories and movements described above permit all movements of the blade holder unit 1 in the substantially horizontal and approximately vertical directions and in the positive and negative directions with respect to the base plane. This is shown in the top right-hand portion of the FIGS. 2 and 3.

(16) The present invention has considerable advantages when compared to the kinematic structure and configuration of the machine made according to European patent No. 1819457. These advantages are as follows.

(17) In practice, the presence of two independent servomotors to move the blade holder unit 1 in the horizontal direction makes it possible to position the metal sheet to be bent at any point in the work zone. This is not possible on the system made according to the European patent cited above where the metal sheet must be positioned perfectly in the centre of the work zone.

(18) The presence of two mechanisms with independent control means that it is possible to vary the torque delivered by each motor to match the force required. In some cases it is even possible to create a counter torque to obtain the right balance of forces required.

(19) A further advantage with respect to European patent No. 1819457 is that the mechanism according to the present invention enables different trajectories to be implemented on the two horizontal and vertical work units. This makes it possible to obtain variable bends on parts during production and in particular to obtain parts with variable geometry such as ferrules.

(20) The mechanism according to the present invention makes it possible to vary the overall configuration of the panel bender so as to compensate for any variations due to thermal or mechanical influences.

(21) The invention described above refers to a preferred embodiment.

(22) Nonetheless, it is clear that the invention is susceptible to numerous variations which lie within the scope of its disclosure as defined in the attached claims.