1. A resonant power supply for light-emitting devices, comprising:
an inverter including two DC input terminals and two AC output terminals, and configured to convert a direct current from the two DC input terminals into an alternating current through the two AC output terminals;
a resonant circuit connected in series to at least one of the two AC output terminals; and
an LED circuit connected in series to the resonant circuit, and configured to emit lights as the alternating current is applied.
2. The resonant power supply for light-emitting devices of claim 1, wherein the inverter includes two serially connected switches and two serially connected capacitors between the two DC input terminals, and the two AC output terminals are connected to two junctions between the two switches and the two capacitors.
3. The resonant power supply for light-emitting devices of claim 2, wherein the resonant circuit is connected between one of the two AC output terminals and the LED circuit.
4. The resonant power supply for light-emitting devices of claim 2, wherein the resonant circuit includes a capacitor and an inductor connected between one of the two AC output terminals and the LED circuit.
5. The resonant power supply for light-emitting devices of claim 2, wherein the LED circuit is connected between the resonant circuit and one of the two AC output terminals.
6. The resonant power supply for light-emitting devices of claim 1, wherein the inverter includes two serially connected switches connected between the two DC input terminals, one of the two AC output terminals connects one of the two DC input terminals, and the other AC output terminal connects one junction between the two switches.
7. The resonant power supply for light-emitting devices of claim 6, wherein the resonant circuit includes a capacitor connected between one of the two AC output terminals and the LED circuit and an inductor connected between the other AC output terminal and the LED circuit.
8. The resonant power supply for light-emitting devices of claim 6, wherein the resonant circuit includes a capacitor and a transformer having a primary winding connected between the two AC output terminals via the capacitor and a secondary winding connected to the LED circuit.
9. The resonant power supply for light-emitting devices of claim 8, wherein the transformer has a leakage inductance serving as an inductor of the resonant circuit.
10. The resonant power supply for light-emitting devices of claim 8, wherein the resonant circuit further includes an inductor connected between the secondary winding and the LED circuit.
11. The resonant power supply for light-emitting devices of claim 6, wherein the resonant circuit includes a capacitor and a transformer having a primary winding connected between the two AC output terminals via the capacitor and a center tap secondary winding, and the center tap secondary winding has two ends tied together through a diode respectively to be a first output node and a center tap end serving as a second output node.
12. The resonant power supply for light-emitting devices of claim 11, wherein the transformer has a leakage inductance serving as an inductor of the resonant circuit.
13. The resonant power supply for light-emitting devices of claim 11, wherein the resonant circuit further includes an inductor connected between the secondary winding and the LED circuit.
14. The resonant power supply for light-emitting devices of claim 1, wherein the LED circuit includes series-connected light-emitting diodes.
15. The resonant power supply for light-emitting devices of claim 1, wherein the LED circuit includes two anti-parallel series-connected light-emitting diodes.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A unit for feeding and cutting into lengths a strip of wrapping material, comprising:
a conveyor on which to support and advance the strip;
first cutting means, operating cyclically and in conjunction with the conveyor supporting and advancing the strip, by which the selfsame strip is divided transversely into single leaves of predetermined length;
second cutting means, operating cyclically and in conjunction with the conveyor supporting and advancing the strip, serving to score at least one transverse tear-off line on each leaf;
third cutting means, operating cyclically and in conjunction with the conveyor supporting and advancing the strip, serving to score a longitudinal tear-off line combining with the transverse tear-off line to delimit a removable portion of the leaf;
wherein the second and third cutting means are rigidly associated one with another and form part of a common rotary device.
2. A unit as in claim 1, wherein the second and third cutting means combine at one and the same operating station to define a cutting edge of \u201cL\u201d profile interacting with at least one set of anvil means presented by the conveyor.
3. A unit as in claim 2, wherein the conveyor consists in a rotating drum and the rotary device comprises a shaft, of which the axis extends parallel to the axis of the drum, carrying second cutting means embodied as a radial blade and third cutting means embodied as a disc blade.
4. A unit as in claim 3, comprising means by which to adjust the timing of the stroke made by the second and the third cutting means, relative to that of the first cutting means.
5. A unit as in claim 4, wherein adjustment means comprise means by which to adjust the angular position of the second and third cutting means about the axis of the relative supporting shaft.
6. A unit as in claim 5, wherein the drum is equipped with a plurality of anvil blades, angularly equispaced and combining with a fixed blade to provide the first cutting means.
7. A unit as in claim 6, wherein the drum presents a plurality of sectors, angularly equispaced and identical in number to the anvil blades, each presenting an outer surface fashioned with a respective seat such as will accommodate an insert providing the anvil means offered to the cutting edge of \u201cL\u201d profile presented by the second and third cutting means.
8. A unit as in claim 7, wherein the sectors are embodied in carbon fiber and the inserts are embodied in metallic andor resilient material and are interchangeable.
9. A method of cutting strip material into discrete lengths, including the steps of feeding a strip of wrapping material to a conveyor, severing the strip on transverse cut lines through the agency of first cutting means, cyclical in operation, so as to separate the single leaves, and scoring a succession of transverse lines and longitudinal lines on the strip with second and third cutting means to create a removable portion on each successive leaf, wherein the steps of scoring the longitudinal line and the transverse line occur in succession at a single operating station, and the step by which a cut is made on the transverse line to separate each leaf from the strip precedes at least the step of scoring the transverse line.
10. A unit as in claim 1, comprising means by which to adjust the timing of the stroke made by the second and the third cutting means, relative to that of the first cutting means.
11. A unit as in claim 10, wherein adjustment means comprise means by which to adjust the angular position of the second and third cutting means about the axis of the relative supporting shaft.
12. A unit as in claim 3, wherein the drum is equipped with a plurality of anvil blades, angularly equispaced and combining with a fixed blade to provide the first cutting means.
13. A unit as in claim 2, comprising means by which to adjust the timing of the stroke made by the second and the third cutting means, relative to that of the first cutting means.
14. A unit as in claim 13, wherein adjustment means comprise means by which to adjust the angular position of the second and third cutting means about the axis of the relative supporting shaft.
15. A unit as in claim 3, wherein adjustment means comprise means by which to adjust the angular position of the second and third cutting means about the axis of the relative supporting shaft.