US 5,875,664 A · Programmable servo-motor quality controlled continuous multiple coil spring forming method and apparatus

Abstract

A spring forming machine is provided with closed-loop feedback from sensors which monitor dimensions of the coils and heads of the spring being formed, servo motors which control wire feed speed, coil radius and pitch forming elements, and coiling direction. Video cameras form pictorial images of the spring being formed. The images are digitized and fed to a central computer, along with images from similar machines forming similar springs, which compares the signals, such as photometric images, from the different machines, which represent actual spring dimensions, with a single stored image relating to the desired dimensions, such as head shape, coil diameter, and the positions and angles of bends. Discrepancies are correlated with causation data, such as feed roll slippage or material hardness variations, and adjustment signals are sent to the machines. Machines producing errors are interrogated more frequently by the computer. Large errors or failures to respond to adjustments triggers an alarm.

Claims26

Dependent claims

A method of forming a continuous multiple coil spring having a plurality of alternately oppositely oriented coils joined by interconnecting heads, the method comprising the steps of:

(a) storing spring head shape information related to a programmed shape of a head for interconnecting an adjacent pair of coils to be formed of a wire;
(b) feeding a wire at a controlled linear rate, and, while so feeding the wire:
generating a coil radius electrical control signal related to a programmed radius of coils to be formed of the wire,
generating a coil pitch electrical control signal related to a programmed pitch of coils to be formed of the wire, and
bending the wire to the programmed radius in response to the coil radius electrical control signal and to a programmed pitch in response to the coil pitch electrical control signal;
to thereby form a first coil therein having a first orientation;
(c) further feeding the wire at a controlled rate, and, while so feeding the wire, guiding the wire, in response to a head shape electrical control signal responsive to the stored head shape information, to form a first interconnecting head lying generally in a plane perpendicular to the first coil;
and
(d) repeating step (b) to thereby form a second coil in the wire parallel to the first coil, having a second orientation opposite the first orientation, and interconnected with the first coil by the interconnecting head formed in step (c).

6 more elements

An apparatus for forming a continuous multiple coil spring having a plurality of alternately oppositely oriented coils joined by interconnecting heads from wire comprising:

a machine housing;
a wire forming device mounted on the housing;
means on said housing for feeding wire longitudinally to the forming device at a linear rate;
means for storing spring head shape information related to a programmed shape of a head to be formed interconnecting an adjacent pair of coils to be formed of a wire, and for generating a spring head shape signal, in response to the stored information, representative of the shape of the interconnecting heads to be formed;
a spring head shape sensor for monitoring the shape of a spring head formed by the forming device and generating a monitoring signal in response thereto;
and
the forming device including a servo amplifier having inputs connected to the spring head shape signal generating means and the sensor and operable to compare a the spring head shape signal and the monitoring signal, and to generate an error signal as a result of the comparison, and means, responsive to a spring head shape signal and the error signal for bending the wire fed thereto to form an interconnecting head of the programmed shape between two adjacent coils.

4 more elements

A method of forming springs comprising the steps of:

(a) storing spring shape information related to a programmed shape of spring lengths to be formed of a wire;
(b) feeding wire at a controlled linear rate, and, while so feeding the wire:
generating a curvature electrical control signal related to a programmed curvature to be formed in the wire,
generating a pitch electrical control signal related to a programmed pitch to be formed in the wire,
varying at least one of the electrical control signals to produce a programmed shape that varies as a function of the feeding of the wire, and
bending the wire to the programmed curvature in response to the curvature electrical control signal and to a programmed pitch in response to the pitch electrical control signal,
thereby forming a first spring length in accordance with the programmed shape;
(c) monitoring the shape of the formed first spring length and generating a shape monitoring signal in response thereto, the monitoring step including the steps of generating a pictorial image of the formed first spring length and resolving the pictorial image to produce the monitoring signal responsive to the actual shape of the formed first spring length;
(d) modifying at least one of the electrical control signals in response to the monitoring signal;
and
(e) repeating step (b) to form a second spring length in response to the electrical control signals so modified to form a second spring length.

8 more elements

A method of forming springs comprising the steps of:

(a) providing a plurality of spring forming machines each controlled to operate simultaneously to produce springs of the same shape in accordance with a plurality of machine parameter settings of the respective machine;
(b) centrally storing digitized spring shape reference data containing information related to a programmed shape of spring lengths to be formed by each of the machines;
(c) operating each of the machines to produce springs in accordance with the spring parameter settings of the respective machine;
(d) monitoring springs produced by each of the machines and generating multidimensional spring shape data of the shape of the monitored springs;
(e) selecting one of the machines of the plurality of machines;
(f) separately comparing, with the spring shape reference data, the generated data of the shape of a spring produced by the selected one of the machines and generating a comparison signal carrying information of the existence of a dimensional discrepancy in the spring produced by the selected machine;
(g) digitally analyzing information derived from the multidimensional data of the shape of the spring produced by the selected machine and the comparison signal;
(h) digitally deriving from the analysis of step (g) at least one adjustment signal that will tend to correct a discrepancy determined to exist in the spring produced by the selected machine;
(i) adjusting at least one parameter of the selected machine in response to the adjustment signal;
and
(j) repeating steps (c) through (i).

8 more elements

Dependencies are inferred from the claim text.

Programmable servo-motor quality controlled continuous multiple coil spring forming method and apparatus

Life of this patent

Programmable servo-motor quality controlled continuous multiple coil spring forming method and apparatus

Life of this patent

Abstract

Claims26