Method and apparatus for preventing curling of lead strips during expansion

Claim 1

A method of making lead-acid storage battery plates comprising: advancing a narrow lead strip, having a predetermined thickness, longitudinally between two rows of progressive dies and cutters, said strip having a central, longitudinal lug-forming portion and two expandable grid-forming portions flanking the lug-forming portion and extending to both longitudinal edges of the strip, and said rows comprising a plurality of dies and cutters which converge in incremental steps on the central lugforming portion of the strip passing between them; periodically shearing bottom-border-forming sections from each longitudinal edge as the strip advances between the first set of dies and cutters, each of said sections being linked to successive sections and to the remainder of said grid-forming portion by unsheared portions of the strip intermediate the sections; expanding a first part of the remaining grid-forming portions along the longitudinal edges thereof by periodically shearing rectangular wire-like segments from said edges into a plurality of tiers of undulatory skeletal elements extending at acute angles to the plane of said lug-forming portions and such that successive tiers are offset one from the other and joined one to the other by a plurality of nodes which join the ends of successive segments in one tier to the centers of like segments in successive tiers; at approximately midway through the progressive dies, engaging the underside of said border-forming sections and pushing it upwardly to pull on the already expanded part and remove any deleterious curl forming therein; expanding the remainder of the grid-forming portions in the same manner as done for said first parts; said nodes for said first parts and remainders having rectangular, vertically transverse cross-sections and widths significantly greater than said predetermined thickness and equal to the sum of the widths of the adjoining skeletal elements, whereby two reticulated portions comprising a plurality of polygonal paste-retaining cells bounded by said skeletal elements and nodes are formed with a continuous row of unexpanded bottom-border-forming sections on the lateral edges thereof and extend at acute angles from the central portion in gull-wing fashion when viewed head-on; leveling the thusly expanded strip by folding said reticulated portions down into nearly the same plane as said central portion; uniformly stretching the reticulated portions in directions substantially perpendicular to the direction the strip is fed through the dies by urging each tier of skeletal elements in those directions independently of the other tiers to uniformly size the cells, stretch the reticulated portions to a predetermined width and slightly rotate the rectangular nodes such that diagonally opposing edges of the nodes become salient in the principal planes of the reticulated portions; flattening the reticulated portions by further rotating said nodes and compressing said salient edges into plateaus and thereby convert the rectangular cross-sections of said nodes to polygonal cross-sections having twO opposing sides thereof laying in planes substantially parallel to the faces of the pasted plate and spaced one from the other by a distance greater than said predetermined thickness but substantially less than twice said predetermined thickness; substantially engulfing the reticulated portions in a leady active material paste and sandwiching same between strips of paper which are substantially coextensive with said reticulated portions; drying the paper-bound pasted strip; and finally segmenting the pasted strip into individual battery plates.

Claim 2

A method of making lead-acid storage battery plates comprising: advancing a narrow lead strip, having a predetermined thickness, longitudinally between two rows of progressive dies and cutters, said strip having a central, longitudinal lug-forming portion and two expandable grid-forming portions flanking the lug-forming portion and extending to both longitudinal edges of the strip, and said rows comprising a plurality of dies and cutters which converge in incremental steps on the central lugforming portion of the strip passing between them; periodically shearing bottom-border-forming sections from each longitudinal edge as the strip advances between the first set of dies and cutters, each of said sections being linked to successive sections and to the remainder of said grid-forming portion by unsheared portions of the strip intermediate the sections; expanding a first part of the remaining grid-forming portions along the longitudinal edges thereof by periodically shearing rectangular wire-like segments from said edges into a plurality of tiers of undulatory skeletal elements extending at acute angles to the plane of said lug-forming portions and such that successive tiers are offset one from the other and joined one to the other by a plurality of nodes which join the ends of successive segments in one tier to the centers of like segments in successive tiers; at approximately midway through the progressive dies, engaging the underside of said border-forming sections and pushing it upwardly to pull on the already expanded part and remove any deleterious curl forming therein; expanding the remainder of the grid-forming portions in the same manner as done for said first parts; said nodes for said first parts and remainders having rectangular, vertically transverse cross-sections and widths significantly greater than said predetermined thickness and equal to the sum of the widths of the adjoining skeletal elements, whereby two reticulated portions comprising a plurality of polygonal paste-retaining cells bounded by said skeletal elements and nodes are formed with a continuous row of unexpanded bottom-border-forming sections on the lateral edges thereof and extend at acute angles from the central portion in gull-wing fashion when viewed head-on; leveling the thusly expanded strip by folding said reticulated portions down into nearly the same plane as said central portion; uniformly stretching the reticulated portions in directions substantially perpendicular to the direction the strip is fed through the dies by urging each tier of skeletal elements in those directions independently of the other tiers to uniformly size the cells, stretch the reticulated portions to a predetermined width and slightly rotate the rectangular nodes such that diagonally opposing edges of the nodes become salient in the principal planes of the reticulated portions; flattening the reticulated portions by further rotating said nodes and compressing said salient edges into plateaus and thereby convert the rectangular cross-sections of said nodes to polygonal cross-sections having twO opposing sides thereof laying in planes substantially parallel to the faces of the pasted plate and spaced one from the other by a distance greater than said predetermined thickness but substantially less than twice said predetermined thickness; substantially engulfing the reticulated portions in a leady active material paste and sandwiching same between strips of paper which are substantially coextensive with said reticulated portions; drying the paper-bound pasted strip; and finally segmenting the pasted strip into individual battery plates.

Claim 3

A method of making lead-acid storage battery plates comprising: advancing a narrow lead strip, having a predetermined thickness, longitdinally between two rows of progressive dies and cutters, said strip having a central, longitudinal lug-forming portion and two expandable grid-forming portions flanking the lug-forming portion and extending to both longitudinal edges of the strip, and said rows comprising a plurality of dies and cutters which converge in incremental steps on the central lug-forming portion of the strip passing between them; periodically shearing bottom-border-forming sections from each longitudinal edge as the strip advances between the first set of dies and cutters, each of said sections being linked to successive sections and to the remainder of said grid-forming portion by unsheared portions of the strip intermediate the sections; expanding a first part of the remaining grid-forming portions along the longitudinal edges thereof by periodically shearing rectangular wire-like segments from said edges into a plurality of tiers of undulatory skeletal elements extending at acute angles to the plane of said lug-forming portions and such that successive tiers are offset one from the other and joined one to the other by a plurality of nodes which join the ends of successive segments in one tier to the centers of like segments in successive tiers; at approximately midway through the progressive dies, forcing the nodes at said centers into substantial alignment between cooperating tool members on said dies and cutters to remove any deleterious curl forming in the expanded part; expanding the remainder of the grid-forming portions in the same manner as done for said first parts; said nodes for said first parts and remainders having rectangular, vertically transverse cross-sections and widths significantly greater than said predetermined thickness and equal to the sum of the widths of the adjoining skeletal elements, whereby two reticulated portions comprising a plurality of polygonal paste-retaining cells bounded by said skeletal elements and nodes are formed with a continuous row of unexpanded bottom-border-forming sections on the lateral edges thereof and extend at acute angles from the central portion in gull-wing fashion when viewed head-on; leveling the thusly expanded strip by folding said reticulated portions down into nearly the same plane as said central portion; uniformly stretching the reticulated portions in directions substantially perpendicular to the direction the strip is fed through the dies by urging each tier of skeletal elements in those directions independently of the other tiers to uniformly size the cells, stretch the reticulated portions to a predetermined width and slightly rotate the rectangular nodes such that diagonally opposing edges of the nodes become salient in the principal planes of the reticulated portions; flattening the reticulated portions by further rotating said nodes and compressing said salient edges into plateaus and thereby convert the rectangular cross-sections of said nodes to polygonal cross-sections having two opposing sides thereof laying in planes substantially parallel to the faces of the pasted plate and spaced one from the other by a distance greater than said predetermined thickness but substantially less than twice said predetermined thickness; substantially engulfing the reticulated portions iN a leady active material paste and sandwiching same between strips of paper which are substantially coextensive with said reticulated portions; drying the paper-bound pasted strip; and finally segmenting the pasted strip into individual battery plates.

Claim 4

A method of making lead-acid storage battery plates comprising: advancing a narrow lead strip, having a predetermined thickness, longitdinally between two rows of progressive dies and cutters, said strip having a central, longitudinal lug-forming portion and two expandable grid-forming portions flanking the lug-forming portion and extending to both longitudinal edges of the strip, and said rows comprising a plurality of dies and cutters which converge in incremental steps on the central lug-forming portion of the strip passing between them; periodically shearing bottom-border-forming sections from each longitudinal edge as the strip advances between the first set of dies and cutters, each of said sections being linked to successive sections and to the remainder of said grid-forming portion by unsheared portions of the strip intermediate the sections; expanding a first part of the remaining grid-forming portions along the longitudinal edges thereof by periodically shearing rectangular wire-like segments from said edges into a plurality of tiers of undulatory skeletal elements extending at acute angles to the plane of said lug-forming portions and such that successive tiers are offset one from the other and joined one to the other by a plurality of nodes which join the ends of successive segments in one tier to the centers of like segments in successive tiers; at approximately midway through the progressive dies, forcing the nodes at said centers into substantial alignment between cooperating tool members on said dies and cutters to remove any deleterious curl forming in the expanded part; expanding the remainder of the grid-forming portions in the same manner as done for said first parts; said nodes for said first parts and remainders having rectangular, vertically transverse cross-sections and widths significantly greater than said predetermined thickness and equal to the sum of the widths of the adjoining skeletal elements, whereby two reticulated portions comprising a plurality of polygonal paste-retaining cells bounded by said skeletal elements and nodes are formed with a continuous row of unexpanded bottom-border-forming sections on the lateral edges thereof and extend at acute angles from the central portion in gull-wing fashion when viewed head-on; leveling the thusly expanded strip by folding said reticulated portions down into nearly the same plane as said central portion; uniformly stretching the reticulated portions in directions substantially perpendicular to the direction the strip is fed through the dies by urging each tier of skeletal elements in those directions independently of the other tiers to uniformly size the cells, stretch the reticulated portions to a predetermined width and slightly rotate the rectangular nodes such that diagonally opposing edges of the nodes become salient in the principal planes of the reticulated portions; flattening the reticulated portions by further rotating said nodes and compressing said salient edges into plateaus and thereby convert the rectangular cross-sections of said nodes to polygonal cross-sections having two opposing sides thereof laying in planes substantially parallel to the faces of the pasted plate and spaced one from the other by a distance greater than said predetermined thickness but substantially less than twice said predetermined thickness; substantially engulfing the reticulated portions iN a leady active material paste and sandwiching same between strips of paper which are substantially coextensive with said reticulated portions; drying the paper-bound pasted strip; and finally segmenting the pasted strip into individual battery plates.