APPARATUS FOR MONITORING TEST ANIMAL ACTIVITY

• US 3,803,571 A
• Filed: 10/24/1972
• Issued: 04/09/1974
• Est. Priority Date: 10/21/1971
• Status: Expired due to Term

• Current Assignee: Hans G. Luz
• Original Assignee: Hans G. Luz
• Inventors: Luz, Hans G.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/299,775
• Time in Patent Office: 532 Days
• Field of Search: 340/279,258C 235/92MT 331/65 119/155
• US Class Current: 119/421
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals
• CPC Class Codes: A01K 29/005 Monitoring or measuring activity, e.g. detecting heat or mating
• CPC Class Codes: A61B 2503/40 Animals
• CPC Class Codes: A61B 2503/42 for laboratory research
• CPC Class Codes: A61B 5/1105 of laboratory animals, e.g. activity
• CPC Class Codes: G01N 27/72 by investigating magnetic variables

Abstract

Animals of different selected groups are provided with electrically conducting and/or ferromagnetic actuator elements of different predetermined electrical conductivity and/or magnetic permeability. Test coils are arranged about the animal enclosure and are connected to different measuring circuit apparatus, one for each group to be monitored, which apparatus are individually responsive to the presence of the test animals provided actuator elements within the magnetic field of the coils. In this manner, each animal of each group will produce a discrete signal representative of the group to which it belongs.

Claims

1. Apparatus for determining the activity of different groups of test animals located within an enclosure, comprising:

actuator means carried by the test animals, said means having a different electrical conductivity-magnetic permeability, characteristic for each group;

coil means located within the enclosure such that the test animals and actuators carried thereby can be brought closely adjacent thereto during natural movement of the animals;

alternating voltage source means connected to said coil means;

circuit means for generating a signal each time an animal carrying an actuator is immediately adjacent said coil means, said circuit means including separate detector means for each animal group individually responsive to the impedance change in Said coil means produced by an animal with actuator of the corresponding group being located nearby for producing a unique signal identifying the animal as to group.

2. Apparatus as in claim 1, in which the actuator means include a first actuator of high magnetic permeability to be carried by a first group of animals, a second actuator constructed of a material of relatively good conductivity to be carried by a second group of animals and a third actuator constructed of a material having a good conductivity substantially less than that of the second actuator to be carried by the animals of the third group.

3. Apparatus as in claim 1, in which said circuit means includes means interconnecting said coil means and said voltage source means forming a balanced bridge in the absence of test animals and producing an unbalance signal when an animal with actuator means is located within influential range of said coil means, and means responsive to both the polarity and magnitude of said unbalance signal for producing a signal identifying the group of test animals unbalancing the bridge.

4. Apparatus as in claim 3, in which said bridge means includes second coil means electrically identical with said first recited coil means and located remotely from the test animals, said first and second coil means being serially arranged with said alternating voltage source means.

5. Apparatus as in claim 3, in which said bridge means includes a resistance of value equal to the serial resistance of said coil means, and a capacitor having a capacitive reactance equal to the combined inductive reactance of said coil means, said resistance and capacitance being serially arranged with said coil means across said alternating voltage source.

6. Apparatus as in claim 3, in which said means for producing an identifying signal includes phase selective rectifier means having a pair of input terminals, means interconnecting the alternating voltage source to one of said rectifier means input terminals, means connecting the unbalance signal with the other rectifier means terminal, and trigger circuit means fed by the rectifier means output to produce a signal identifying the group of animals unbalancing the bridge.

7. Apparatus for determining which of three test animals moves into impedance modifying range of a coil energized by an alternating voltage source, comprising:

a first metallic actuator carried by one of said animals having relatively high magnetic permeability and relatively low electrical conductivity;

a second metallic actuator of geometry identical to said first actuator carried by another of said animals and having a relatively low magnetic permeability and relatively high electrical conductivity;

a third metallic actuator of identical geometry to said first and second actuators having the same magnetic permeability as said second actuator and less electrical conductivity; and

means responsive to the three different levels of impedance change in said coil produced by the animals with the respective actuators for producing respectively individual identifying signals.

8. Apparatus for providing signals indicative of any one of a number of different levels of change of impedance in coil means energized by a source of substantially constant frequency electrical power, comprising:

first and second phase measuring means each having a pair of input terminals and an output terminal at which a signal appears proportional to the product of the voltage value at a first of said input terminals and the cosine of the difference in phase angles between the two inputs;

means interconnecting the voltage at said coil means and said first input terminals of said first and second phase measuring means;

first phase shifting means interconnecting the electrical power source and the second input terminal of the first phase measuring means;

second phase shifting means interconnecting the electrical power source and the second input terminal of the second phase measuRing means;

said first and second phase shifting means being so adjusted that for at least one level of coil means impedance change the output of the first phase measuring means is zero and for at least one other level of coil means impedance change the second phase measuring means output is zero; and

thresholded means connected to the outputs of said first and second phase measuring means for providing signals definitive of the different levels of coil means impedance change.