BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates, generally, to the manufacture of metal oxide varistors (“MOVs”) and the assembly of metal oxide varistors (“MOVs”) for use in surge suppression or surge protection, which provides increased part density, as compared to similar current methods.
2. Description of the Prior Art
Presently, metal oxide varistors (“MOVs”) placed side by side with spacing for the legs and insulating coating between them. Metal oxide varistors (“MOVs”) are also some made into modules with two or more layered and sharing a common lead.
During normal assembly of a surge suppression or surge protection device the metal oxide varistors (“MOVs”) are placed side by side with wide enough spacing for the leads and epoxy covering. This limits the number of metal oxide varistors (“MOVs”) are placed inside the units.
Luo, U.S. Pat. No. 7,623,019, issued Nov. 24, 2009, discloses method of assemble of 3 metal oxide varistors (“MOVs”) sandwiched with 2 common leads between the metal oxide varistors (“MOVs”). It is difficult in manufacturing to keep the metal oxide varistors (“MOVs”) parallel during assembly making manufacturing an expensive and difficult process.
SUMMARY OF THE INVENTION
It is, therefore an object of the present invention to provide a method of manufacturing and assembly without the limitations of the prior methods above.
By manufacturing metal oxide varistors (“MOVs”) with offset leads and also making them with opposite facing leads, the metal oxide varistors (“MOVs”) can be interlock during assembly. Interlocking the metal oxide varistors (“MOVs”) during assembly allows more metal oxide varistors (“MOVs”) in a smaller space without the added cost joining the metal oxide varistors (“MOVs”) in to one part. Interlocking the metal oxide varistors (“MOVs”) also does not require the metal oxide varistors (“MOVs”) to be epoxy coated because touching surfaces are electrically connected.
DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 shows how 3 metal oxide varistors (“MOVs”) would normally be placed with the spacing between them.
FIG. 2 is prior art from Luo, U.S. Pat. No. 7,623,019. Luo shows 3 metal oxide varistors (“MOVs”) sharing 2 common leads in the center and two single lead on each end. This allows the metal oxide varistor (“MOVs”) spacing to be more dense than FIG. 1, but has an added cost of a difficult and expensive manufacturing process.
FIG. 3 is a drawing of two metal oxide varistors (“MOVs”), the one on the left is a front left, wide lead pattern; and the one on the right is a front right, narrow lead pattern. Also shown in this drawing, the metal oxide varistor (“MOV”) on the left has the leads crossing above center and the metal oxide varistor (“MOV”) on the right has the leads crossing below center. The arrangement of the leads, being wide and above center, and narrow and bellow center, allows the metal oxide varistors (“MOVs”) to be spaced as close to together as in FIG. 2 with the difficult and expensive manufacturing cost of a single lead.
FIGS. 4 and 5 shows a side and bottom view of the 2 metal oxide varistors (“MOVs”) arranged tight together without the leads interfering with each other. This is how they are arranged when installed in to the printed circuit board. Because the two leads between the metal oxide varistors (“MOVs”) can be connected together on the print circuit board, the metal oxide varistors (“MOVs”) do not need to be epoxy coated.
FIGS. 6 and 7 shows a side and bottom view of the 4 metal oxide varistors (“MOVs”) arranged tight together without the leads interfering with each other.
FIG. 8 is a drawing of two of the same type of metal oxide varistors(“MOV”), the view on the left shows a left attached lead, wide and above center; and the view on the right shows a right attached lead, narrow and below center. The arrangement of the leads, being wide and above center on one side, narrow and bellow center on the other side, again allows the metal oxide varistors (“MOVs”) to be spaced as close to together as in FIG. 2 with the difficult and expensive manufacturing cost of a single lead.
FIGS. 9 and 10 shows a side and bottom view of the 2 metal oxide varistors (“MOVs”) of the type shown in FIG. 8 arranged tight together without the leads interfering with each other. Here just 2 are shown, but any number of metal oxide varistors (“MOVs”) may be stacked.