Abstract:
An electric noise absorber for holding a conduit of an electronic device comprises a retaining case composed of two box-shaped cases and auxiliary cases. A sponge-like member is fitted into the auxiliary case to prevent longitudinal movement of the cord or cable. A box-shaped case contains a magnet having a recess for receiving the cord or cable. It is possible to easily and securely attach and detach the electric noise absorber to the cord or cable by simply opening and closing the cases.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an electric noise absorber for absorbing electric noise which is generated within an electronic device or which enters from the outside into the device through a line cord or cable. 
     As a method for absorbing such noise, it is well-known that a ferrite can be attached to encircle a line cord or cable. In this method, two pieces of half ring-shaped ferrite are simply attached by adhesive tape around the line cord. It is troublesome to attach the separate pieces to the line cord or cable and to detach the adhesive tape. Upon attachment of the noise absorber to line cord or cable, the pieces are apt to easily become detached from the line cord due to an uncovered state of the ferrite and it can not be used for an extended period of time. In addition, vibration may cause a displacement of the noise absorber from an initially-attached position on the line cord or cable. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to provide an electric noise absorber in which a magnetic body can be held securely to a line cord or cable for an extended period of time. 
     It is another object of this invention to provide an absorber that, whenever required, can easily be attached to and detached from the line cord or cable. 
     It is a further object of this invention to provide an absorber which can effectively absorb electric noise and prevent the noise generation and noise inflow to the electric device. 
     It is a further object of this invention to provide an absorber which can resist longitudinal movement by providing a press member. 
     These objects and other related objects are realized by an electric noise absorber (1) comprising: a magnetic body (3a,3b) axially divided and configured to enclose an outer periphery of an electric conduit (40); a retaining case (2) including a pair of cases (6,7) hingedly connected with each other for housing said magnetic body (3a,3b); an auxiliary case (10a,10b,11a,11b) connected to said retaining case; and an elastic press member (4) sized, shaped, positioned to fit into at least one of said auxiliary case and to hold said conduit (40) in use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention is illustrated diagrammatically in the following drawings wherein: 
     FIG. 1 is a perspective view illustrating an electric noise absorber of an embodiment according to the present invention; 
     FIG. 2 is a top plan view of the retaining case of the embodiment shown in FIG. 1 in a half-opened state; 
     FIG. 3 is a sectional view of the retaining case taken along III--III line of FIG. 2; 
     FIG. 4 is a perspective view of the retaining case of the embodiment in a half-opened state; 
     FIG. 5 is a perspective view of ferrite of the embodiment; 
     FIG. 6 is a sectional view of the electric noise absorber of the embodiment in the longitudinal direction in a closed and locked position; and 
     FIG. 7 is a perspective view of the electric noise absorber of the embodiment for retaining an electric conductor therein. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An embodiment of this invention will be described with reference to FIGS. 1 through 7. 
     Referring to FIG. 1, an electric noise absorber 1 comprises a retaining case 2, a pair of ferrite bodies 3a and 3b, an elastic press member 4. Two cases 6 and 7 are connected by means of a strip hinge 5. The cases 6 and 7 are box-shaped with one open surface, and configured to securely contain therein ferrite bodies 3a and 3b. Side walls 8a, 8b, 9a and 9b of the cases 6 and 7 connect to a distal end of auxiliary cases 10a, 10b, 11a and 11b which house, respectively, therein the elastic press member 4. On the inside surfaces of the outside walls 12a, 12b, 13a and 13b of the auxiliary cases 10a, 10b, 11a, and 11b are provided with small projections 14a, 14b, 15a, 15b which project inwardly and engage with press members 4. Engagement pawls 16 and 17 extend from a center of inner surfaces of rear walls 8a and 9a, and engage with side notches 31a, 31b of the ferrites 3a, 3b shown in FIG. 5. A pair of resilient members 19a and 19b  extend in a longitudinal direction of the case 6 from a bottom wall 18 of the case 6. These members 19a and 19b projects inwardly at end portion and presses upwardly (in FIG. 2) to the back surface of the ferrite 3a. A plate-like hook 20 is provided at a distal end of case 6 opposite to the end where the hinge 5 is provided. A rectangular through hole 22 is provided at an end 21 of case 7 for allowing the insertion of the hook 20. Referring to FIGS. 1 through 6, the elastic press members 4 are sized and positioned to fit tightly into the auxiliary cases 10a, 10b, 11a and 11b, and are shaped in a rectangular parallelopipe and they are greater in depth than the auxiliary cases. 
     Referring to FIGS. 5 and 6, the ferrite bodies 3a and 3b are shaped in a rectangular parallelepiped and provided with rectangular recesses 30a and 30b to enable the passage of the flat cable 40. Notches 31a and 31b provided at the center of the transverse edge of the recesses 30a and 30b to engage with engagement pawls 16 and 17. 
     The electric noise absorber 1 is assembled as hereinafter described. First, the ferrite 3a is fitted into the case 6 to engage the engagement pawl 16 with the notch 31a of the ferrite body 3a. Similarly, the ferrite body 3b is fitted into case 7 to engage the engagement pawl 17 with the notch 31b of the ferrite body 3b. The press members 4 are fitted tightly into auxiliary cases 10a, 10b, 11a and 11b so that small projections 14a, 14b, 15a and 15b dig into the press members 4. Next, the plate-like hook 20 is fitted into the hole 22 to secure the closed state of the retaining case 2. The plate-like hook 20 is manually manipulated toward hinge 5 to open the retaining case 2. 
     As shown in FIG. 7, the retaining case 2 holds a flat cable 40 in the ferrite bodies 3a and 3b. The resilient members 19a and 19b push the back surface of ferrite 3a thereby the abutment surfaces 32a, 32b, 33a and 33b are abutted to each other. The ferrite bodies 3a and 3b tightly encircle the flat cable 40. The press member 4 is configured to fit onto the cable 40 to resist longitudinal sliding of the cable in the noise absorber. 
     The electric noise absorbers 1 contain the ferrite bodies 3a and 3b, and encircle the cable 40 with the ferrite bodies 3a and 3b. By applying an appropriate number of the electric noise absorbers 1, the electric noise flowing in the cable is absorbed by the ferrite body, and the generation of noise is prevented. Noise is measured at various positions along the cable 40 by a noise measuring device. The position where noise is absorbed most efficiently is determined, and the noise absorber is located to the correct position. It is preferable that the most appropriate number of the noise absorbers to be used are experimentally determined by measuring the noise absorbing efficiency. The ferrite bodies 3a and 3b absorb the electric noise that is generated outside or enters the electronic device through the cable 40. 
     The plate-like hook 20 is pushed toward the hinge 5 so as to detach the cases 6 and 7 from the cable or to change position of the cases 6 and 7. Easy attachment of the cases 6 and 7 and their detachment from the cable 40 of the cases 6 and 7 are attained. It is also possible to secure the retaining case 2 to a portion of the electronic device with a double-sided adhesive tape on the cases 6 and 7. 
     Regarding the retaining case 2, it is made of a synthetic resin, alternatively another material such as an insulator (e.g. paper) can be employed. The press member 4 is made of elastic material such as sponge or rubber. Press members 4 juxtaposed may be fitted into one of the cases 6 and 7 or into one opposing portion of cases. Moreover the press member 4 may be attached on outer surfaces of side walls 8a, 8b, 9a, and 9b by adhesive in place of housing the auxiliary cases 10a, 10b, 11a, 11b. Regarding the magnetic substance, either hard or soft ferrite can be used. Further, a plastic or rubber magnet which is made by mixing magnetic powder of ferrite with plastic or rubber can also be used. 
     Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims in the invention may be practiced otherwise than as specifically described.