Patent Application
20090161333
A. Field of the Invention
The present invention relates to electric components. More particularly, the present invention relates to shaped connection leads of electric devices for improving the initial positioning of the devices on a circuit board at assembly.
B. Description of the Prior Art
Conventionally, an electric component or device such as a transistor 1 shown in
In order to solve the above or other problems, numerous suggestions have been made. U.S. Pat. No. 4,541,034 to Fanning discloses a special design of thru-hole insertable terminal that has multiple bends as well as a free-ended tab formed internally of the terminal by a blanking or die cut. The Fanning terminals each requires a tab bending after insertion of the terminal for the purpose of a temporary securement as a prerequisite to a permanent soldering process which calls for a dedication of energy and precious machine time. Besides, the formation of a deflection tab through a blanking process limits the choice of material to make such terminals to be flat or in a blade shape although the majority of component leads are cuts of thin wires or rods with round cross sections. It is impractical if not impossible to form a bending tab amid a run of a thin wire. Adding to that difficulty of actual manufacturing is the complex machine dynamics to process the temporary and permanent securements in an automated assembly line. I.e., Fanning terminals need three distinctive movements of vertical insertion of the component and two opposite deflections of the tabs inside the thru-holes.
U.S. Pat. No. 7,045,720 to Sagayanathan, et al. suggests a component lead system having two opposing leads shaped into a clip to hold a substrate or circuit board area between thru-holes. Each lead is made of different leg sections that are normally under bias rendering downward or upward insertion of the component more difficult which means more energy input is needed just to overcome the excess of bias.
Other similar patents include U.S. Pat. No. 3,747,045 to Stross; U.S. Pat. No. 5,726,862 to Huynh et al.; U.S. Pat. No. 5,586,008 to Kozel et al. However, none of these component leads take a simple uniform shape that can be applied to different types of lead material to effectuate a single action flipped insertion of components, thereby completing a secure cling of the same to the designated positions on the circuit board.
In view of these shortcomings of the existing component terminals and leads, an objective of the present invention is to provide auto-cling leads of electric components that allow an unassisted fastening of components onto a circuit board.
Another objective of the present invention is to provide a standardized shape of components leads regardless of their material type that will result in the same reliable cling of the components until they are permanently soldered to the circuit board, and also be stronger after being soldered to the circuit board.
Yet another objective of the present invention is to provide leads can be inserted into the thru-holes of the circuit board through a 90-degree swivel motion that causes a secure flush cling of the leads and in turn a low profile mounting of the electric component onto the circuit board around the thru-holes.
In accordance with the present invention, automatic clinging leads of an electric device are provided for an unassisted mounting on thru-holes of a printed circuit board. The electric device may be either an active or passive electronic component that comprises an electric element extending in a longitudinal direction and having a predetermined conduction function. There are multiple terminal regions formed on the electric element for making electrical connections of the same with another element on the circuit board. The electric device also comprises conductive leads each having three continuous right-angled sections including a longitudinal proximal end section extending from the terminal region of the electric element, a predetermined length of latitudinal distal end section extending at right angle with respect to the proximal end section, and a bent midsection for connecting the proximal and distal end sections at the diametrically opposite right angle to the angle between the proximal and distal end sections meeting at a cross of their imaginary projection lines to provide a generally laterally extending lead with three alternating bends between the three sections. With such electric device, an insertion of the leads through a 90-degree swivel motion into the thru-holes of the circuit board causes a secure flush cling of the leads and in turn a low profile mounting of the electric device onto the circuit board around the thru-holes.
The auto-cling leads are in a blade shape and have a flat cross section. Alternatively, the leads are in a rod shape and have a round cross section.
Embodiments of the invention will now be described by way of example with reference to the accompanying drawings.
Similar reference numbers denote corresponding features throughout the attached drawings.
With reference to
Lead 80 has a first straight section 81 extending vertically from a bottom side of device 60 that stands substantially upright from a PCB 70. PCB 70 has a plurality of thru-holes including a hole 72. The lower limit in sizing a PCB thru-hole is supposed to be set to slightly exceed the largest girth or diameter of the leads of components mounted to accommodate them with little resistance. Different PCBs have had individually sized thru-holes for specified devices with leads although they are more expensive to make.
The drawings depict that transistor device 60 may have a stop shaped on each of the leads to show the present invention applied to existing manufactured components although such stops or individual hole sizing may not be necessary thanks to the present invention. Further, according to the present invention, the upper limit of hole 72 also becomes free of a tight tolerance without a concern of displacement of device 60 before and after a subsequent soldering process since the lead of device 60 is adapted to hold device 60 onto PCB 70 without having to engage hole 72.
Instead, a second straight section of a flat shank 83 extends from first section 81 via a first 90-degree bend 82 to make a flat engagement with PCB 70 at its dielectric upper surface. A vertical third straight section 88 of the lead penetrating the hole 72 interconnects the shank 83 via a second 90-degree bend 84 and the fourth straight section of a horizontal pin 87 via a third 90-degree bend 85. The spaced second and third bends 84, 85 along with the connecting straight section 88 work in unity as a pivoting means when inserting device 60 into hole 72 during assembly. Pin 86 is terminated by a tip 87, which is under gravity biased toward a circuit trace (not shown) until a mass of solder 50 is formed to cover the whole pin 86 connecting the same to PCB 70 electrically for good.
Therefore, each of leads 80 of the electric device constitutes three continuous right-angled sections including longitudinal proximal end section 81 extending from the internal terminal region of the electric device, latitudinal distal end section 86 extending at right angle with respect to the proximal end section 81, and bent midsection 83/88 for connecting the proximal and distal end sections 81, 86 at the diametrically opposite right angle to the angle between the proximal and distal end sections 81, 86 meeting at a cross of their imaginary projection lines to have the lead 80 extending generally laterally with three alternating bends 82, 84 and 85 between the three right-angled sections.
In step two of
Each of the leads 180 has a first straight section 181 extending vertically from a bottom side of device 160 that stands substantially upright from PCB 70 penetrating a thru-hole 172 of PCB 70. The lower limit in sizing a PCB thru-hole is supposed to be set to slightly exceed the largest diameter of the round leads of components mounted to accommodate them with little resistance. The upper limit of hole 172 needs not to be within a tight tolerance without a concern of displacement of device 160 before and after a subsequent soldering process since the lead 180 holds device 160 onto PCB 70 without having to engage hole 172.
Second straight section of a parallel shank 183 extends from first section 181 via a first 90-degree bend 182 to make a flat engagement with PCB 70 at its dielectric upper surface. A vertical third straight section 188 of the lead running through the hole 172 interconnects the shank 183 via a second 90-degree bend 184 and the fourth straight section of a horizontal pin 187 via a third 90-degree bend 185. The spaced second and third bends 184, 185 along with the connecting straight section 188 work in unity as a pivoting body when inserting device 160 into hole 172 during assembly.
Pin 186 is terminated by a tip 187, which is under gravity biased toward a circuit trace (not shown) until a mass of solder 50 is formed to cover the whole pin 186.
In step two of
The electric device can be made as a transformer, transistor or capacitor. A wire bending machine can easily wire bend any of the leads of these common electrical devices into the stepped profile as shown in the drawings. The stepped profile provides an easier connection and more durable connection than the connection of the prior art.
Therefore, while the presently preferred form of the automatic clinging leads of electric devices have been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention, as defined and differentiated by the following claims.
