Articulated bending brake for sheet metal forming

Abstract

A bottom tool/bending die for use in sheet metal forming. The bottom tool includes a pair of movable dies that provide substantially continuous support of a work piece as it is being deformed. Each die includes an upper surface configured to contact the work piece and having an inner and an outer edge. As the die moves in the tool, the inner edge of the upper surface is closer to a center of rotation of the die than the outer edge. In some embodiments, the upper surfaces of the dies are shaped so that a fixed separation is maintained between the inner edges of the dies as they rotate. In at least one embodiment, sector gears are used to control the motion of the dies.

1 . A bending die for use in sheet metal forming, comprising:
 (a) a first movable component including a first working surface, the first movable component and the first working surface extending longitudinally relative to a longitudinal axis of the bending die, the first working surface being generally planar and comprising a first inner edge extending longitudinally relative to the longitudinal axis of the bending die;   (b) a second movable component including a second working surface, the second movable component and the second working surface extending longitudinally relative to the longitudinal axis of the bending die and disposed adjacent to said first working surface, the second working surface being generally planar and comprising a second inner edge extending longitudinally relative to the longitudinal axis of the bending die, the first inner edge and the second inner edge being oriented substantially adjacent to one another in a facing relationship; and   (c) a frame configured to provide support for said first and second movable component, while enabling said first and second working surfaces to move relative to the frame, such that a substantially fixed separation between the first inner edge and the second inner edge is maintained, regardless of a rotational angular displacement of either of the first and second movable components, the frame supporting the first and second movable components using at least one configuration selected from the group consisting essentially of:
 (i) a first configuration wherein each of said first and second movable components comprises at least one sector gear, each such sector gear engaging a linear rack gear portion of the frame, each sector gear and linear rack gear in combination supporting one of the first and second movable components, such that each linear rack gear portion supporting one of the first and second movable components is oriented parallel to each other linear rack gear portion supporting the other one of the first and second movable components; and 
 (ii) a second configuration wherein each of said first and second movable components includes a bearing surface disposed at each end thereof, each such bearing surface at one end of the first and second movable components rotatably engaging one opening in the frame that substantially encloses the bearing surfaces, and each such bearing surface at the other end of the first and second movable components engaging another opening in the frame that substantially encloses the bearing surfaces, each said opening constraining the first and second movable components so that as the first and second movable components move, the substantially fixed separation between the first inner edge and the second inner edge is retained, each of said openings thereby supporting the ends of the first and second movable components, as the first and second movable components pivot relative to each other. 
   
   
   
       2 . The bending die of  claim 1 , wherein the first configuration further comprises a hinge assembly disposed at an end of the first and second working surfaces, the hinge assembly pivotally coupling said first and second working surfaces together, such that a rotational displacement of one of said first and second working surfaces results in a corresponding rotational displacement of the other one of said first and second working surfaces, through an opposite rotational direction. 
   
   
       3 . The bending die of  claim 2 , wherein said frame includes a generally U-shaped portion defined by support members disposed adjacent to the end of one of the first and second working surfaces, such that each linear rack gear portion is attached to a different support member. 
   
   
       4 . The bending die of  claim 2 , wherein each of said first and second working surfaces comprises an elongate sector gear, and each linear rack gear portion extends along its corresponding elongate sector gear. 
   
   
       5 . The bending die of  claim 2 , wherein said frame comprises a first section and a second section, a position of said first section relative to said second section being adjustable to enable a width of a gap separating the adjacent edges of said first and second working surfaces to be adjusted to a desired dimension 
   
   
       6 . The bending die of  claim 1 , wherein said frame comprises a first section and a second section, a position of said first section relative to said second section being adjustable to enable a width of a gap separating the adjacent edges of said first and second working surfaces to be adjusted to a desired dimension. 
   
   
       7 . The bending die of  claim 1 , wherein each of said first and second working surfaces comprises an angled upper surface having a shape selected to facilitate over-bending of the sheet metal. 
   
   
       8 . The bending die of  claim 1 , further comprising a resist element that applies a resisting force to said first and second working surfaces, the resisting force countering at least in part a force applied to deform the sheet metal. 
   
   
       9 . The bending die of  claim 8 , wherein the resist element comprises at least one of a stripper, a spring, an elastomeric material, a hydraulic component, a collapsible support, a movable support, and a pneumatic component. 
   
   
       10 . The bending die of  claim 8 , wherein said resist element comprises:
 (a) a channel, said channel having a dimension substantially equal to said fixed separation;   (b) an elongate block partially disposed in said channel, said elongate block having a dimension smaller than said fixed separation; and   (c) a spring disposed in said channel so as to apply a restoring force against said elongate block in opposition to a deformation of the metal sheet into the channel, such that said elongate block is returned to an original position after the metal sheet is removed following the deformation of the metal sheet.   
   
   
       11 . The bending die of  claim 1 , wherein the second configuration further comprises a sector gear coupled to each one of said first and second working surfaces. 
   
   
       12 . The bending die of  claim 11 , further comprising a prime mover, and a plurality of driven gears configured to drivingly couple with the prime mover, each driven gear being disposed to engage one of said sector gears, such that as each driven gear is rotated, the corresponding sector gear is rotated. 
   
   
       13 . The bending die of  claim 11 , wherein said frame comprises a first section and a second section, a position of said first section relative to said second section being adjustable to enable a width of a gap separating the adjacent edges of said first and second working surfaces to be adjusted to a desired dimension. 
   
   
       14 . The bending die of  claim 1 , wherein the second configuration further comprises a piston and a cylinder assembly disposed adjacent to each of said first and second working surfaces, such that each one of said first and second working surfaces is coupled to a different piston and cylinder assembly, each piston and cylinder assembly applying one of a driving force and a resisting force to a different one of the first and second working surfaces. 
   
   
       15 . The bending die of  claim 14 , wherein each of said first and second working surfaces comprises a wing, such that each wing is coupled to a different piston and cylinder assembly. 
   
   
       16 . The bending die of  claim 14 , wherein said frame comprises a first section and a second section, a position of said first section relative to said second section being adjustable to enable a width of a gap separating the adjacent edges of said first and second working surfaces to be adjusted to a desired dimension 
   
   
       17 . The bending die of  claim 14 , wherein each piston and cylinder assembly comprises one of a hydraulic system, a pneumatic system, and a mechanical system. 
   
   
       18 . The bending die of  claim 14 , wherein each piston and cylinder assembly is coupled to an actuator that controls a movement of said first and second working surfaces. 
   
   
       19 . A bending die for use in sheet metal forming, comprising:
 (a) a first working surface extending longitudinally relative to a longitudinal axis of the bending die, the first working surface comprising an elongate sector gear;   (b) a second working surface extending longitudinally relative to the longitudinal axis of the bending die and disposed adjacent to said first working surface, the second working surface comprising an elongate sector gear; and   (c) a frame configured to provide support for said first and second working surfaces, while enabling said first and second working surfaces to move relative to the frame, such that a substantially fixed separation between adjacent edges of the first and second working surfaces is maintained, regardless of a rotational angular displacement of either of the first and second working surfaces, said frame comprising opposed rack gears, such that the elongate sector gear on each one of said first and second working surfaces engages a different rack gear.   
   
   
       20 . A bending die for use in sheet metal forming, comprising:
 (a) a first working surface extending longitudinally relative to a longitudinal axis of the bending die, a sector gear being coupled to said first working surface;   (b) a second working surface extending longitudinally relative to the longitudinal axis of the bending die and disposed adjacent to said first working surface, a sector gear being coupled to said second working surface;   (c) a frame configured to provide support for said first and second working surfaces, while enabling said first and second working surfaces to move relative to the frame, such that a substantially fixed separation between adjacent edges of the first and second working surfaces is maintained, regardless of a rotational angular displacement of either of the first and second working surfaces;   (d) a prime mover; and   (e) a plurality of driven gears configured to drivingly couple with the prime mover, each driven gear being disposed to engage one of said sector gears, such that as each driven gear is rotated, the corresponding sector gear is rotated.