Electricity: electrical systems and devices – Miscellaneous
Patent
1990-04-03
1991-11-05
Picard, Leo P.
Electricity: electrical systems and devices
Miscellaneous
361395, H05K 118, H05K 506
Patent
active
050634780
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electrical or electronic control key pad.
2. Description of the Relevant Art
French patent No. 83 19245, filed on Dec. 1, 1983, under the name of Mr. Bernard DANGLOT, describes a key pad which permits electrical control codes to be formed. It consists of a closed case containing a device having one or several bulbs with contact blades which are sensitive to a magnetic field. It is characterized in that the opening in the case is covered by a wall with openings, and whose solid part is made of a material which blocks the passage of the magnetic field. It is further characterized in that the blades of one bulb are arranged under each opening in this wall so as to be actuatable under the effect of a magnetic field which is induced by a movable magnet placed in front of the opening, exterior to the case.
Although it is completely satisfactory, the key pad described in the aforementioned patent cannot be used at will in any location due to its volume. The object of the present invention is to obviate this disadvantage by providing an ultrathin key pad and to improve its performance.
SUMMARY OF THE INVENTION
According to this invention, the electrical or electronic control key pad is composed of a case; and a front panel which when closed blocks the magnetic flux, except in the areas where openings are provided for this purpose; one bulb (with blades and pins) for each opening and placed in the case at the level of the front face in order to detect the flux passing through the opening. The control lay pad of this invention further includes a printed circuit in the base of the case and to which the pins of the bulb are connected. Only one of the pins of each bulb is located under the corresponding opening, while the body of the bulb and the other pin are disposed under the solid part of the front panel. The pin placed in front of the opening is curved around in a plane parallel to the front face. The flux generated by a magnet placed in front of the opening can only reach one of the pins of the bulb. The flux is then conducted to the blades in the bulb which are attracted to each other and thus, close the electric circuit. A cable runs either laterally or through the back face of the case to connect the bulbs to a decoder located at a distance. The openings in the panel can be placed in a continuous line parallel to, and a short distance from, the edge of the case. Preferably, the axis of each bulb extends substantially along the center of the panel and the center of one opening.
These and other features of the invention will be understood upon reading of the following description along with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of this invention in perspective without the protective pane;
FIG. 2 is a partial section of this invention taken along the line II--II in FIG. 1; and
FIG. 3 is a top view of this invention, without the guide sheet.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The key pad includes a case 1 of a shallow depth, and closed by a front panel 2, with openings 3. A cable 4 runs from this case 1 connecting it to another case 5 which contains the coder/decoder device.
In the embodiment shown, bulbs 9 to 18 are mounted inside the key pad. Each bulb has two blades which are sensitive to a magnetic field, each blade being extended by a pin 6 or 7, and emerging from the opposite ends of the bulb. FIG. 2 shows the body of the bulb 9 placed in parallel underneath the solid part of the front panel 2. Only the pin numbered 6 extends under the opening 3. Pin 6 is curved around and the free ends of the two pins are attached to a printed circuit. This circuit can be printed directly on the base 19 of the case 1 or on a special panel 8 attached to the base of the case.
A guide sheet 20 with numbers, letters or the like, is glued to the front face 2 over the openings 3. By placing a magnet 21 in front of a mark and an opening 3, a magnetic flux is applied to pin 6 (and exclusively
REFERENCES:
patent: 3559124 (1971-01-01), Posey
patent: 3609524 (1971-09-01), Kazmer
patent: 3713056 (1973-01-01), Hosokawa
patent: 3750062 (1973-07-01), Goto
patent: 3854131 (1974-12-01), Vanderheiden et al.
patent: 4336529 (1982-06-01), Buan
patent: 4380704 (1983-04-01), Wisda
Phillips Michael W.
Picard Leo P.
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