Packaged Bulb Base Orientation

A customer wanted to detect the orientation of a bulb-base in a paper sleeve. If the base is out of position there is potential for damage. A second bulb loaded from the opposite side, will try to occupy the same space and break one or both.

The bulb is enclosed in the paper sleeve and the base cannot be visually detected from its side because of a paper divider, positioned diagonally in the sleeve. The divider is used to separate, cushion, and guide the bulbs into position. The sleeve is 4 inches across. The bulb base’s normally nest in opposing diagonal corners of the sleeve.

The primary purpose of our detector is to verify metal position, not presence. In this application our detector is used like an extended range proximity detector with the ability to measure metal thickness. The threshold adjustment that responds to metal thickness is also ideal for metal positioning where a metal object’s position is proportional to the thickness. In this application, we proposed our self-contained Models DS50RS and DS50TS, although all of our detectors have the ability to detect this condition.

Prime’s dual probe Double Metal Sheet Detector system has a transmitter probe that produces an oscillating magnetic field (60 to 75 kHz) that radiates out to approximately 100 mm (4 inches). A receiver senses the signal without any physical contact and reproduces it internally. Inductive or eddy current reaction impedes the signal transmission through the metal.

The impedance is proportional to metal thickness. The receiver has an output switch that is “on” until the received signal falls below a preset value. Increased metal thickness turns the switch off. This value, adjusted by the end-user, causes the output to remain off as long as thicker metal is between the probes. By comparison, a standard metal proximity sensor is effected by metal in two dimensions, width and height of a target. It does not penetrate metal and is not sensitive to the thickness of metal. Unlike a proximity sensor, a Double Metal Sheet Detector is effected by width, height and depth of metal.

The bulb-base detection is achieved by locating a set of double metal sheet probes so a package with 1 or more bulb-bases pass through the transmitted field. The output of the receiver turns “off” when the metal thickness exceeds (signal drops) a pre-adjusted limit.

Measuring the signal that passes through metal provides a method to solve problems related to metal thickness, shape, position and type of metal. In other Application Notes we review specific examples like:

• foil packet count in a closed box
• steel belted cord alignment in tires
• circuit board copper plating weight
• container seam detection
• molten metal mold closed detection