Pin Terminal

1. Field of the Invention

This invention relates to a pin terminal which is enhanced in strength to meet a small-size design.

2. Related Art

One example of a pin terminal to be connected to a connector is disclosed in Japanese Utility Model Unexamined Publication No. 53-137685. As shown in FIG. 5, a wire 106 is connected to this pin terminal 101 by compressively deforming a conductor clamping portion 101e and a covering clamping portion 101f, and a body portion 101c of this terminal is fitted in a connector housing to position the terminal at a proper location, so that a pin plug-like electrical connection portion 101a for electrical connection to a female terminal of a mating connector (not shown) is projected toward the front side of the connector.

The pin terminal of this type is usually formed by stamping a sheet of electrically-conductive metal such as phosphor bronze and then by processing it into a roll-shape.

By the way, recently, connectors have been increasingly required to have a small-size design, and also the pin terminal under consideration has also been required to have a small-size design for use with a very small current.

It is an object of this invention to provide a pin terminal which is enhanced in strength and also in shaping ability when the pin terminal is formed into a small-size design in accordance with a small-size design of a connector.

The above object of the present invention has been achieved by a pin terminal characterized in that a shaped piece, which is stamped from a metal sheet, and has at least an electrical connection portion, a body portion, an interconnecting portion and a wire connection portion in this sequence, is processed into a roll-shape; the body portion has a cylindrical shape larger in diameter than the electrical connection portion and the interconnecting portion; and the shaped piece has a drawn portion of a corrugated configuration circumferentially provided between the body portion and each of the electrical connection portion and the interconnecting portion.

In the shaped piece, the drawn portion of a corrugated configuration is provided between the electrical connection portion and the body portion before the shaped piece is formed into a roll-shape, and therefore the drawn portion has the effect of beams to enhance the strength, so that damage to the electrical connection portion can be prevented.

The drawn portion is also provided between the body portion and the interconnecting portion extending continuously from this body portion, and this drawn portion cooperates with the drawn portion, provided between the body portion and the electrical connection portion, to enhance the shaping ability.

FIGS. 1(a) to (c) are perspective views showing the appearance of a second embodiment of the present invention, as well as enlarged perspective views of important portions thereof;

FIG. 2 is a developed view of a pin terminal of FIG. 1;

FIG. 3 is a cross-sectional view of drawn portions taken along the line X--X and the line Y--Y of FIG. 2;

FIG. 4 is a cross-sectional view showing an important portion of the pin terminal;

FIG. 5 is a cross-sectional view of a conventional terminal attached to a connector; and

FIG. 6 is a a perspective view showing a first embodiment of the present invention.

A preferred embodiment of the present invention will now be described with reference to the drawings.

FIG. 6 shows a pin plug of a first embodiment of the present invention. A pin plug-like electrical connection portion 201a is formed into a small diameter before connecting a wire, and also in order to prevent a holding force of a housing from being reduced in accordance with the small-size design of the connector, the angle of inclination of a body portion 201c is made acute.

With this construction, however, there has been encountered a problem that stresses concentrate on a proximal end portion P of the electrical connection portion 201a of the pin terminal 201, so that the electrical connection portion is liable to be broken.

In view of the circumstance, a second embodiment of the present invention will now be described hereinafter.

FIGS. 1(a) to (c) perspective views showing the appearance of the second embodiment of a pin terminal of the present invention, as well as enlarged perspective views of important portions thereof. FIG. 2 is a developed view of the pin terminal of FIG. 1, FIG. 3 is a cross-sectional view taken along the line X--X and the line Y--Y of FIG. 2, and FIG. 4 is a cross-sectional view showing an important portion of the pin terminal.

This pin terminal 1 includes an electrical connection portion 1a of a smaller diameter having a rounded, conical, tapered distal end, a body portion 1c of a cylindrical shape which has a tapered surface 1b progressively increasing in diameter from the electrical connection portion 1a, and a cylindrical interconnecting portion 1d of a smaller diameter extending from a rear end of the body portion 1c to a conductor clamping portion 1e and a covering clamping portion 1f which cooperate with each other to form a wire connection portion.

At a region corresponding to the proximal end portion of the electrical connection portion 1a, there is provided a drawn portion 2 which is circumferentially drawn into a corrugated configuration, this drawn portion 2 covering part of the tapered surface 1b. A similar drawn portion 2 is also provided at that region covering a rear end of the body portion 1c and the interconnecting portion 1d.

For forming the pin terminal 1, a metal sheet of phosphor bronze is stamped into a predetermined shape, and a plurality of shaped pieces 3 connected together are separated from one another as shown in FIG. 2, and each shaped piece 3 is processed into a roll-shape. Since the body portion 1c of a larger diameter, and the electrical connection portion 1a of a smaller diameter and the interconnecting portion 1d of a smaller diameter, which extend continuously from the body portion 1c, are abruptly drawn, the drawn portions 2, having a corrugated shape as shown in FIG. 3, are formed at these portions by pressing.

As a result of providing the drawn portions 2, in the pin terminal 1 formed into a roll-shape, the distance between adjacent ridges at an outer corrugated surface 2a of the interconnecting portion 1d is larger, and the radius of curvature of the curved portions of this outer surface is larger, whereas the distance between adjacent ridges at an inner corrugated surface 2b is smaller, and the radius of curvature of the curved portions of this inner surface is smaller, as seen from the cross-sectional view of FIG. 4 in which the body portion 1c is viewed from its rear end toward the front end of the pin.

With this configuration of the outer corrugated surface 2a and the inner corrugated surface 2b, strains of the metal material itself caused by the abrupt drawing can be absorbed, and a crack and tear at the drawn portion can be prevented.

Therefore, the pin terminal, shaped to meet a small-size design of a connector, can be satisfactorily formed into a small-size design.

More specifically, the curved portions at the outer corrugated surface 2a achieve the effect of beams to enhance the strength of the drawn portion, and the curved portions at the inner corrugated surface 2b achieve an enhanced shaping ability of the drawn portion because of a compressed construction thereof.

The thus shaped pin terminal is connected to the connector (not shown) which is formed into a small-size design according to a conventional procedure. At this time, the tapered surface 1b of the body portion 1c is engaged in a receiving portion formed on a connector housing (not shown), so that the terminal is held at a proper position. The body portion 1c is formed into a cylindrical shape of a larger diameter, and the conductor clamping portion 1e extending from the interconnecting portion 1d has a smaller diameter. The reason for this is to eliminate the possibility that burrs, produced on the conductor clamping portion when this conductor clamping portion is compressively deformed, are obstructive as in the prior art when the terminal is to be inserted into the housing.

As described above, in the pin terminal of the present invention, the corrugated drawing is provided at the abruptly drawn portions, and therefore the strength and the shaping ability can be enhanced, and particularly when the small-size design is used, the strength capable of providing a sufficient withstanding force can be achieved.