Locking Structure of Wire Rod for Filter Element

1. Field of the Invention

The present invention relates to a simplified locking structure of a wire rod for a filter element.

2. Description of the Prior Art

One of the locking structures of this kind is disclosed by the applicant in Japanese Patent Publication No. 16164/1988, and another in Japanese Patent Laid-open Application No. 9204/1988.

In the case of the former locking structure, one end portion of the wire rod, bent and wrapped around an insert member, is inserted in a recess formed on the circumferential surface of a cylindrical body, and securely locked by means of a locking bolt, which is inserted through a hole formed on the opposed walls of the insert member and the recess, and is engaged in a threaded portion formed in the bottom of the hole.

The above-described prior art structures are advantageous for filter elements of high precision filtering material made through precision finishing method.

In the latter locking structure, the locking structure is largely simplified by utilizing a wedge instead of the insert member and also the locking bolt of the former case, and thereby the end portion of the wire rod being pushed by the wedge and secured within a locking hole.

The aforementioned prior art patents, which were disclosed by the same applicant of the present invention, are provided with certain advantages and effects according to the improved locking structure, accuracy or dimension of the filter element.

There are still some problems that an insert member or a wedge is necessary as a locking member. In particular, in the case when an inexpensive filter element can be provided by using cheaper materials such as plastics, the locking structure should be further simplified to expedite mass production.

An object of the present invention is to provide a locking structure of a wire rod for a filter element, whereby an improved locking structure is enabled by an utmost simplest arrangement.

The invention is concerned with a locking structure of a wire rod for a filter element, which comprises a support member of a desired form with a desired passage therein for fluid, a wire rod having a desired section wound along a threaded groove formed on an outer or inner peripheral surface of the support member for maintaining a continuous slit between each of the adjacent windings of the wire rod, whereby an end portion of the wire is bent and forcibly pushed in a locking hole formed on the support member to be securely locked to the support member. More specifically, the wire rod may be formed to be triangular in cross section, and retained on the peripheral surface of the support member such that the apex of the triangular section can be fitted to the threaded groove having a corresponding angle formed on the peripheral surface.

The end portion of the wire rod is simply locked by pushing it into the locking hole, thereby fixing the end portion extremely rapidly and efficiently. In addition, the support member having a passage can be provided with a threaded groove having a desired form, along which a wire rod having a corresponding section can be fitted to form a continuous slit between windings, thereby filtration or separation of solid and liquid being capable according to the dimension or length of the slit.

FIG. 1 is a partially cutaway front view of a filter element, in which a wire locking structure according to the present invention is disposed;

FIG. 2 is a partially cutaway front view of a filter element according to another embodiment, in which a support member is formed as an inverted cone;

FIG. 3 is a plan view of a support member formed as a flat plate; FIG. 4 is a partially cutaway front view of a filter element, in which a support member is formed as another structure of a cylinder; and FIG. 5 is an enlarged perspective view of the wire locking structure, illustrating an end portion of a wire rod and a locking hole.

The preferred embodiments of the invention will now be described with reference to the accompanying drawings.

In FIG. 1 to 4, four types of filter elements are represented. These are different in the form of the support member A. FIG. 4 shows an embodiment, in which a wire rod is wound on the inner surface of the support member. The reference letter A denotes a support member commonly in each of FIGS. 1 to 5. The locking structure of the wire rod is the same in all embodiments.

Referring now to FIG. 1, an embodiment comprising a cylinder A1 as support member is illustrated. Similarly, FIGS. 2 and 3 represent each embodiment comprising a support member of an inverted conical form A2, and of a flat plate A3. FIG. 4 represents another embodiment including a cylinder A1 as shown in FIG. 1, but the arrangement of a plurality of passage B provided in support member A is different from each other.

Support member A is provided with a coil-shaped, spiral or helical groove 2 having an accurate pitch size on the outer (FIGS. 1, 2 and 3) or inner (FIG. 4) peripheral surface thereof. A wire rod 1 is wound along the groove 2 so as to be maintained in a coiled form. A reference numeral 3 denotes a continuous slit formed between the adjacent windings of the wire 1, which slit forms a passage for the fluid, which is subject to filteration or separation of solid and liquid.

A bent portion is formed at each end of wire rod 1. A reference numeral 5 denotes a locking hole formed at a terminus 4a of the threaded groove 2 in the end area of support member A. The bent portion 4 can be pushed into the locking hole 5 and secured therein. The hole 5 is preferably formed at a right angle or less with respect to the winding direction of wire rod 1 and is formed slightly smaller in diameter than wire rod 1, and larger in depth than the length of bent portion 4. Further, the locking hole 5 may be formed slightly larger in diameter at open end portion 5a than the remaining portion to ease the initial engagement of bent portion 4 with the locking hole 5.

Accordingly, at each of the start and terminus of winding of the wire rod 1 on support member A, the bent portion 4 can be pushed into the locking hole 5, and thus be firmly locked.

In the aforementioned embodiment, a metal wire having a triangular section is shown as wire rod 1 for the filter element. Another form of a section, such as round, rectangular, or trapezoidal, can be selected for wire rod 1. Further, any material, such as ceramic, carbon fiber or plastic instead of metal, can be preferably used. In addition, if necessary, a suitable adhesive can be also utilized for increasing adhesion between the locking hole 5 and bent portion 4.

According to the invention, an end portion of the wire rod can be securely and simply locked by being bent and merely pushed in the locking hole formed on the support member, which can be of a preferable configuration, thereby effecting high working facility and a reduction of production cost. Further, a stable locking of the wire rod is assured without causing looseness.