Multi-mode structural weld monitor on a time base

Claim 3

A method as defined in claim 1, further comprising selectively varying the starting time and duration of a time bracket in accordance with a desired weld characteristic indication.

Claim 4

A method as defined in claim 1, further comprising selecting the beginning of one of said time brackets to occur at the start of the weld cycle, and the end of said one time bracket to occur at the time of maximum dimensional expansion of the weld, whereby the measured change in electrode separation during said one time bracket represents an indication of the maximum size of the weld.

Claim 5

A method as defined in claim 1, further comprising selecting one of said time brackets to occur after the maximum dimensional expansion of the weld has occurred during the weld cycle.

Claim 6

In a weld monitor system for tracking the separation between a pair of welder electrodes, at least one of which is movable, wherein a workpiece is positioned between the electrodes, and wherein the expansion, melting, contraction and solidification of the weld in the workpiece during a weld cycle causes variation in electrode separation, the improvement comprising: means for producing a continuous output potential proportional to electrode separation occurring during a plurality of predetermined time brackets within the weld cycle; means for defining a first time bracket of a predetermined duration within the weld cycle; means responsive to said output potential for producing a first signal proportional to the change in electrode separation during said first time bracket; means for defining a later, second time bracket of a predetermined duration within the weld cycle; and means responsive to said output potential for producing a second signal proportional to the change in electrode separation during said second time bracket.

Claim 7

In a weld monitor system for tracking the separation between a pair of welder electrodes, at least one of which is movable, wherein a workpiece is positioned between the electrodes, and wherein the expansion, melting, contraction and solidification of the weld in the workpiece during a weld cycle causes variation in electrode separation, the improvement comprising: means for producing a continuous output potential proportional to electrode separation occurring during a plurality of predetermined time brackets within the weld cycle; means for defining a first time bracket of a predetermined duration within the weld cycle; means responsive to said output potential for producing a first signal proportional to the change in electrode separation during said first time bracket; means for defining a later, second time bracket of a predetermined duration within the weld cycle; and means responsive to said output potential for producing a second signal proportional to the change in electrode separation during said second time bracket.

Claim 8

The improvement according to claim 5, further comprising: means for defining a third predetermined time bracket later than said second time bracket and within the weld cycle; and means responsive to said output potential for producing a third signal proportional to the change in electrode separation during said third time bracket, the boundary of said second and third time brackets corresponding to the time of maximum expansion of the weld.

Claim 9

The improvement according to claim 5, further comprising first storage means for storing a potential proportional to said output potential at the beginning of said first time bracket; and wherein said first signal-producing means comprises first differential amplifier means, coupled to said output potential-producing means and to said first storage means, for comparing the output potentials at the beginning and end of said first time bracket to produce said first signal as the output of said first differential amplifier means; and further comprising second storage means for storing a potential proportional to said output potential at the beginning of said second time bracket; and wherein said second signal-producing means comprises second differential amplifier means, coupled to said output potential-producing means and to said second storage means, for comparing the output potentials at the beginning and end of said second time bracket to produce said second signal as the output of said second differential amplifier means.

Claim 10

The improvement according to claim 7, wherein said means for defining said first and second time brackets comprise first and second presettable interval counter means adapted to be enabled at the starts of said time brackets and to provide outputs at the ends of said time brackets, respectively.

Claim 11

The improvement according to claim 8, further comprising third storage means coupled to the outputs of said first and second differential amplifier means and of said first and second counter means for storing said first and second signals at the end of each of said time brackets.

Claim 12

The improvement according to claim 9, further comprising a digital voltmeter coupled to said third storage means to provide a digital indication of the stored first and second signals.