US 4,114,450 AGranted

Electronic recording accelerometer

AssigneeSystems Consultants, Inc.

InventorsLawrence M. Shulman, Norman Weingart

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Abstract

A self-contained and internally powered shock, temperature and relative humidity acquisition and recording device particularly adapted for the rapid, accurate and automatic analysis of material handling and transportation facilities and procedures. The apparatus includes transducers which are used to sense shock, temperature and humidity in analog form. The analog signals generated by the transducers are converted to digital signals, i.e., binary multi-bit words which by means of digital logic and solid state memory devices, statistical and time dependent information are stored for an operating interval as long as two weeks. Thereafter the device is coupled to an interrogation system which generates output records from the collected data in operator selected density profiles or time histories.

Claims15

Dependent claims

Apparatus for sensing and recording, for subsequent retrieval, environmental data such as shock, temperature and relative humidity, comprising, in combination:

a substantially ruggedized case for housing said apparatus in the form of a simulated parcel and including a power source therein for operating said apparatus over a predetermined period of time such as the time required for shipping said case from one destination to another;
a plurality of environmental data sensors located in said case and being operable to be responsive at least to shocks encountered bidirectionally along three mutually perpendicular axes and providing respective analog output signals having amplitudes which are a measure of the magnitude of the respective shocks encountered;
analog signal multiplexer circuit means coupled to said plurality of data sensors and being operable to provide a repetitive multiplexed sequence of data signal samples of said analog output signals;
electrical circuit means coupled to said signal samples and being responsive thereto to classify each of said data signal samples by means of voltage comparator circuit means into amplitude windows of predetermined increments and including encoding means for generating a multi-bit digital code word corresponding to the largest amplitude window reached by each data signal sample;
a statistical digital memory coupled to said electrical circuit means and having a respective addressible memory location for each digital code word and being operable to statistically count and store in binary format at each memory location the number of respective digital code words generated over a predetermined sampling period;
a time tagged digital memory coupled to said electrical circuit means and having time dependent addressible memory locations for a predetermined number of sampling periods and being operable in one mode to selectively store in binary format the largest value of a code word occurring within at least one sampling period and in another mode to store in binary format the number of time periods wherein code words of less than a minimum amplitude window are generated;
and
means coupled to said digital memory for selectively reading out on demand the binary formats of said memory locations for generating statistical and time histories of the data stored therein.

5 more elements

A method for sensing and recording shock data in a simultated parcel comprising generating an analog signal in response to shock sensed at least along one reference axis, taking repetitive data samples at sub-intervals of a sampling time interval of said analog signal at a predetermined repetition rate, converting the discrete amplitudes of the data samples to amplitude window signals, coverting the amplitude window signals into respective multi-bit binary code words, determining from a predetermined number of successive data samples whether a predetermined minimum shock event exists, applying said binary code words for each data sample successively to a statistical digital memory and successively comparing data samples and storing the largest value sensed over a predetermined sampling time interval, thereafter addressing a memory location having an address corresponding to the largest value sensed and increasing the binary count contained in said memory location of said statistical memory by one count when said predetermined minumum shock event is present, and addressing a memory address location corresponding to said time interval in a time tagged memory in one mode of operation and reading in a binary value thereat of the value sensed during said time interval.

Dependencies are inferred from the claim text.