Events recorders

Claim 2

An events recorder for recording changes in condition of an apparatus and their times of occurrence, and comprising: a stepping motor; clock pulse means for supplying said motor with pulses to energize said motor intermittently so that said motor is held in its stationary positions by the remanent magnetism of the motor in the intervals between energizations; timing means driven by said motor to provide a measure of actual time; input means for receiving signals representing said changes in condition; recording means for recording said changes, and their times of occurrence is provided by said clock means, upon a recording medium; and standby battery means for maintaining operation of said clock means and to enable recording to continue in the event of a power failure.

Claim 3

A recorder as claimed in claim 1, wherein said timing means comprise switch means to give a unique switching combination for each of a predetermined number of movements of said motor.

Claim 4

A recorder as claimed in claim 2 wherein said switch means comprise angle encoders.

Claim 5

An events recorder as claimed in claim 1, wherein the said recording means records events and times in multibit digitally code words.

Claim 6

An events recorder as claimed in claim 1, wherein said recording means records events and times in digitally coded words and said recording medium is driven independently of time.

Claim 7

An events recorder as claimed in claim 5, wherein said recording means and recording medium are stationary during recording.

Claim 8

A recorder as claimed in claim 1 and comprising sensing means for sensing whether said apparatus to be monitored is on or off.

Claim 9

A recorder as claimed in claim 7 for monitoring television receiver use, wherein said sensing means is a pickup coil for picking up oscillations from the line circuit of said receiver.

Claim 10

A recorder as claimed in claim 1, wherein said stepping motor is of the synchronous type having relatively movable magnetic circuit arrangements, one of which has two magnetic circuits each with its own energizing winding arrangement, and said clock pulse means comprises a clock pulse generator arrangement for producing in said winding arrangements respective pulse trains of current with the same repetition rate but different phase, the improvement comprises circuitry for producing said pulse trains such that in each pulse train the current pulses have alternating directions and a spacing such that the pulses in one train occur within the intervals between pulses in the other train, so that said motor will be intermittently energized and will be held in its stationary positions by its remanent magnetism in the currentless intervals between energizations.

Claim 11

An arrangement as claimed in claim 9, wherein said circuitry comprises a first circuit for producing two pulse trains differing in phase by about 90* and overlapping in time and a second circuit for producing from the latter trains said two trains which energize said motor.

Claim 12

An arrangement as claimed in claim 10, wherein said first circuit is a two-stage twisted ring counter.

Claim 13

An arrAngement as claimed in claim 10, wherein said second circuit is a differentiating circuit.

Claim 14

An arrangement as claimed in claim 12, wherein said second circuit comprises for each of said winding arrangements a differentiating circuit having capacitance and inductance, said inductance provided by said winding arrangement.

Claim 15

An arrangement as claimed in claim 9, wherein said circuitry comprises: a clock pulse generator; a two-stage twisted ring counter connected to be triggered by the said clock pulse generator and with its outputs connected to one end of respective ones of said winding arrangements; and two capacitive voltage dividers to intermediate points of which the other ends of respective ones of said windings are connected.