Abstract: A low cost device which changes rapidly, significantly, irreversibly, and accurately when it is exposed to a predetermined temperature is disclosed. The device of the present invention employs a bimetallic disk which changes its configuration when it is exposed to a predetermined temperature. Before firing, the disk is captured by a recess in the device casing. When the disk is exposed to a predetermined temperature, it changes configuration and escapes its confinement from its orginal location in the recess. A spring propels the disk from its original location to a different location. Additionally, the spring ensures that the disk cannot return to its original location. This device has a minimal number of parts so that it is easily and inexpensively manufactured. It can be configured to sense either high temperature or low temperature. The low temperature device can be used in conjuction with irreversible temperature labels such that the combination records both a high and a low temperature exposure.

Abstract: An infrared thermometer has a field of view selected so that the temperature of the crop growing in a field is accurately measured. The infrared thermometer may be mounted on a support pole in a field to substantially continuously monitor the foliage temperature of the growing crop. In one preferred embodiment, the infrared thermometer comprises and instrument housing structure provided with an infrared telescope mounted on a turntable that scans through an angle of the field, while an electronic circuit simultaneously integrates the output of the infrared telescope. The angle to be scanned is selected by the user in accordance with his needs. In another embodiment, the infrared thermometer comprises a novel sensor head block including an aperture which provides a wide, elongated oval field of view for an infrared sensor provided therein. In both embodiments, the elongated oval field of view has a width that is at least four times its height.

Abstract: An apparatus for use in determining the temperature of or at a specific area by measuring the infrared radiation from that area through the use of a reflector structure to direct the radiation from the area to an infrared detector can be improved by using a laser to provide two light beams which are directed so as to intersect at a distance from the apparatus corresponding to the principal focus of the reflector structure.

Abstract: An electrically powered instrument having a handle which is adapted to be engaged by the hand of a user during the utilization of the instrument can include a switch-type structure which is actuated by the mere engagement of the hand with the handle without any physical or mechanical motion occurring. The switch includes electrodes extending along the handle which are electrically insulated from one another and which are located in such a manner that they are electrically connected through the user's hand when the hand engages the handle. The switch also includes a power source or supply for applying a voltage between the electrodes and a discriminating or detection structure for detecting the change in the electrical resistance between the electrodes occurring either when the handle is engaged by the hand of the user or when the handle is released by the hand of the user.

Abstract: A movable instrument intended for utilization in detecting a difference which is capable of being optically detected between adjacent locations can be constructed so as to include an optical sensor for producing an output which is proportional to the difference between various locations and an illumination source operatively connected to the optical sensor for providing a level of brightness which is proportional to the output of the optical sensor. Such an instrument is preferably a device which is used in determining the temperature of a surface. When the invention is utilized in conjunction with such an instrument the apparent intensity of the light emitted from the illumination source provides a convenient analog indicator facilitating the instrument being pointed at either the hottest or coldest portion of the surface.

Abstract: A temperature indicating device for use in indicating when the temperature of the device has been changed to a predetermined temperature can be constructed so as to utilize a snap spring such as a bimetal bowed washer capable of rapidly changing from a first configuration to a second configuration when the temperature of the spring is changed to a predetermined temperature. In a device of the invention the spring is located within an internal cavity of a housing in such a manner as to hold an indicator member within the housing so that it is visible from the exterior of the housing when the spring is in the first configuration. When the temperature of the spring is changed so as to cause the spring to go to the second configuration the indicator member is released so as to be free to fall within the cavity to a position in which it is no longer visible. If desired the indicator member may be coated with a coating indicating a specific temperature other than the predetermined temperature.