Method and equipment for making jewelry products, in particular tennis-type bracelets

Abstract

A method of making tennis bracelets includes coupling together collet elements ( 2 ) in a repetitive series, wherein an L-shaped lateral appendage ( 3 ) of a collet element is inserted into a through hole ( 6 ) of an immediately adjacent collet element and then bent against a face ( 7 ) of the collet element to which it belongs. The collet elements are inserted according to the repetitive series into an assembly template ( 10 ) implemented as a self-supporting unit provided with fasteners ( 16 ) for fastening the unit to first and second carriage supports ( 22, 36 ) of first and second machines ( 18, 19 ), which cause the assembly template to translate under a die block ( 26 ) of a press device ( 24 ) of the first machine. The lateral appendages ( 3 ) of the collet elements are bent in succession under a laser welding head ( 38 ) of the second machine, for welding the appendages ( 3 ) to their respective collet elements.

1 . An equipment for making link chain jewelry or costume jewelry products, wherein a plurality of collet elements identical to one another are arranged side by side according to a repetitive series that develops longitudinally, to be linked together by an L-shaped lateral appendage protruding in a cantilever fashion from a same face and on a same side of each collet element, which is first inserted through a central hole of another immediately adjacent collet element and then bent against the face of the collet element to which the appendage belongs; the equipment comprising
 an assembly template for the collet elements, configured to receive the collet elements coupled according to said repetitive longitudinal series within a channel of adjustable width delimited by two relatively mobile jaws of the assembly template, at least one of the jaws comprises a surface plate configured to receive, resting the surface plate, said collet elements from the side opposite to the face from which the L-shaped appendage protrudes in a cantilever fashion;   
       i) wherein the assembly template comprises a self-supporting unit provided with a fastener for fastening the assembly template to a support; 
       ii) at least one first machine, comprising: a first stationary pedestal; respective first guides integrally carried by the first pedestal; a first carriage support, movable along the first guides in a sliding manner along a first path having a pre-set length and configured to receive integrally, yet in a removable manner, said assembly template; first adjustable actuators for moving the first carriage support along the first guides; and a press device supported by the first pedestal at a first end of the first path facing towards a first end-of stroke position of the first carriage support, wherein the assembly template lies lower than, but not under, the press device; the press device being provided with an interchangeable die block and a stop for stopping the die block in a position in which the die block is adapted to interfere with the lateral appendages, the die block being configured to bend in succession, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, as a consequence of the transit of the carriage support under the die block; 
       iii) at least one second machine, comprising: a second stationary pedestal; respective second guides integrally carried by the second pedestal; a second carriage support, movable along the second guides in a sliding manner along a second path having a pre-set length and configured to receive integrally, yet in a removable manner, said assembly template; second adjustable actuators for moving the second carriage support along the second guides for fractions of motion equal to a centre-to-centre distance or pitch between said collet elements coupled according to said repetitive series; and a welding head supported by the second pedestal above the second carriage support and at a first end of the second path facing towards a first end-of-stroke position of the second carriage support, wherein the assembly template lies lower than, but not under, the welding head; the welding head facing towards the second guides and being configured to weld, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, each lateral appendage to the respective collet element to which each lateral appendage belongs, as the second carriage support carries along the collet elements under the welding head. 
     
     
         2 . The equipment according to  claim 1 , wherein the fastener for fastening the assembly template to a support is configured to integrally and removably couple the assembly template to, selectively, the first and second carriage supports. 
     
     
         3 . The equipment according to  claim 1 , wherein said first and second machines are usable in sequence, so that the at least one second machine receives a first assembly template from the at least one first machine after the bending of the lateral appendages has been carried out, while the at least one first machine is free to receive a second assembly template provided with collet elements having still to be bent lateral appendages. 
     
     
         4 . The equipment according to  claim 1 , wherein said first and second guides of each one of said first and second machines are defined by opposite longitudinal sides of, respectively, first and second H-beams integrally fixed to the respective first and second pedestals; at least said first carriage support comprising a rigid frame structure H-shaped in a direction parallel to the first guides and comprising a first pair of legs engaging said first guides and a second pair of legs configured to support said assembly template at respective opposite ends of the assembly template and substantially flush with said stop of the die block. 
     
     
         5 . The equipment according to  claim 4 , wherein the press device comprises: a pair of support feet integrally fixed to the first pedestal on both opposite sides of the first guides, wherein the first guides are arranged between said support feet; a plurality of guiding columns integrally fixed to the support feet, on top of the support feet, at a bottom end of the guiding columns; a first plate element integrally fixed to a top end of the guiding columns; a second plate element slidably engaging said guiding columns and carries, at the bottom, said die block; and a motor carried by the first plate element and adapted to move the second plate element along the guiding columns, to selectively move the second plate element closer to or away from the support feet; said stop of the die block comprising respective upper ends of the support feet, said motor being configured to keep said second plate element locked in abutment against the upper ends of the support feet, to arrange the die block in a first operating position, in which the die block is adapted to interfere with the lateral appendages of the collet elements; and to selectively move the die block into a second operating position, in which the die block is farther away from the carriage support and the second plate element is in proximity to or against the first plate element. 
     
     
         6 . The equipment according to  claim 5 , wherein the die block comprises a metal block provided at the bottom with a longitudinal groove oriented parallel to the first guides and configured to receive, in a through manner, an upper edge of the jaws of the assembly template delimiting said channel and configured so that at least said lateral appendages of the collet elements protrude in a cantilever fashion from the collet elements; said groove having a first open end facing the side of the first end of the first path and a second open end opposite to the first one and facing a second end of the first path facing towards a second end-of-stroke position of the first carriage support, in which the assembly template has fully passed under the press device; said groove being centrally equipped with a longitudinal rib extending from the second end of the groove towards the first end of the groove; without occupying at least an end stretch of the groove immediately adjacent to the first end; said rib being delimited towards said first end by a first inclined plane extending from a flat top surface of the longitudinal rib towards a bottom wall of the longitudinal groove, on the side of the first end of the bottom wall; the longitudinal groove being internally provided with, at said end stretch of the first end of the longitudinal groove, a pair of lateral projections delimiting a channel in between the lateral projections, aligned with the longitudinal rib, and delimited towards the first end by respective second inclined planes oriented like the first inclined plane. 
     
     
         7 . The equipment according to  claim 1 , wherein said first adjustable actuators comprise: a worm screw carried idle by the first pedestal under the first carriage support for at least an entire length of the first path; a nut, through which the worm screw engages, carried by said first carriage support, on the side of the first end of the first path; a gear device for rotating the worm screw, carried by the first pedestal; and a driving wheel, provided with a handle for manual operation, for actuating the gear device; the gear device being configured so that a transmission ratio of the gear device is changeable. 
     
     
         8 . The equipment according to  claim 1 , wherein said second adjustable actuators comprise: a worm screw carried idle by the second pedestal under the second carriage support for at least an entire length of the second path; a nut, through which the worm screw engages, carried by said second carriage support, on the side of the first end of the second path; and an adjustable-speed stepper motor for rotating the worm screw, controlled by a programmable control unit. 
     
     
         9 . The equipment according to  claim 1 , wherein said welding head is a laser welding machine. 
     
     
         10 . A method for making link chain jewelry or costume jewelry products, wherein a plurality of collet elements identical to one another are arranged side by side according to a repetitive series that develops longitudinally, to be linked together by an L-shaped lateral appendage protruding in a cantilever fashion from a same face and on a same side of each collet element, the L-shaped lateral appendage is first inserted through a central hole of another immediately adjacent collet element and then bent against the face of the collet element to which the appendage belongs; the method comprising the steps of:
 a) making an assembly template for the collet elements, formed by a pair of relatively mobile jaws delimiting in between the jaws a channel of adjustable width, a bottom wall of the channel is defined by a surface plate integrally carried by at least one of the jaws; the assembly template comprising a self-supporting unit provided with a fastener for fastening the assembly template to a support;   b) inserting the collet elements, one by one; into said channel, coupling the collet elements according to said repetitive longitudinal series, said collet elements resting on the surface plate on a side opposite to the face from which the L-shaped appendage protrudes in a cantilever fashion, and inserting the L-shaped appendage into the central hole of an immediately adjacent collet element;   c) connecting the assembly template in an integral, yet removable, manner to a first carriage support of a first machine provided with a press device including an interchangeable die block and a stop for stopping the die block in a position in which the die block is adapted to interfere with the lateral appendages of the collet elements;   d) translating said assembly template under the press device throughout a length of the assembly template and along a first path under the die block of the press device, to bend in succession, one at a time, said lateral appendages of the collet elements coupled according to said repetitive series, as a consequence of the transit of the carriage support under the die block;   e) transferring the assembly template, after the bending of the lateral appendages of all the collet elements, onto a second machine, connecting the assembly template in an integral, yet removable, manner to a second carriage support of the second machine, the second machine being provided with a laser welding head;   f) translating said assembly template under the welding head throughout the length of the assembly template and along a second path, by moving the second carriage support under the welding head;   g) stopping the second carriage support under the welding head after each one of a plurality of fractions of motion along said second path equal to a centre-to-centre distance or pitch between said collet elements coupled according to said repetitive series, and activating the welding head to weld each lateral appendage, already bent, to an associated collet element;   h) removing the assembly template and a link chain product formed by, said plurality of collet elements linked in a permanent manner according to said repetitive series.