PT98860B - VARIABLE CONDENSER FOR CORRECTION AND / OR TUNING - Google Patents

Abstract

The invention relates to a capacitor that is intended to be used in UHF tuned filters and also may be used in other frequency bands. The aforementioned capacitor has a small capacity and consists of four basic parts: dielectric insulating body 1, sleeves 2 and 3 and adjustment spindle 4. The body 1 of the dielectric insulator is made of tetrafluoroethylene and includes an axial hole 5 housing an adjustment shaft 4 fitted by means of a thread into an orifice with internal screw threads 7 provided in the sleeve 3 and located at one of the ends of the body 1, whilst the sleeve 2 is fitted at the other end. The screw threads 7 of the sleeve 3 have a smaller pitch than that of the screw threads 8 of the screw 4 in order to obtain good reliability of electrical contact. Mechanical/electrical stability is achieved by means of inserted parts 9 fitted into the sleeves 2 and 3, which are crimped onto the lateral surface of the dielectric insulator 1. <IMAGE>

Description

Currently, several types of variable capacitors for correction and / or tuning are known, which generally consist of two metal plates separated by a dielectric.

material used as a dielectric is a ceramic material that is produced in very special furnaces which makes it considerably expensive.

Therefore, regardless of the greater or lesser reliability of conventional capacitors of small capacity and applicable to tuned UHF filters, they have the drawback that their cost is very high, precisely due to the means (special ovens) necessary to obtain the ceramic material that is used. it uses like dielectric.

DESCRIPTION PA INVENTION condenser according to the present invention, in addition to having a completely original structure and mechanical design, from which numerous advantages derive as mentioned throughout the present description, it has the particularity that the material used as dielectric is tetrafluoroethylene, known commonly as teflon, which has an excellent behavior as a dielectric insulator, in the face of environmental variations such as temperature, humidity, etc.

On the other hand, based on the structure and mechanical design, a very good reliability of the electrical contact of the condenser is achieved, as well as excellent mechanical / electrical stability in the face of certain occasional agents such as strokes,

vibrations, etc. By using the condenser according to the present invention, a good reliability of the adjustment of its components is also achieved.

Basically, the condenser consists of four elementary pieces, one of which is formed by a tubular element with an axial hole that constitutes the dielectric insulator on which coaxial bushings are arranged, in one of which it acts as an upper part with a threaded hole for assembly of the corresponding axis, consisting of a screw, which is lodged inside the hole provided for in the dielectric insulator, through which the regulation is made that allows the capacitor capacity to vary, by changing the distance between the metal parts that are precisely constituted by the two bushings, which are fixed on the lateral surface of the dielectric insulator by a torn inlay with the shape of a square pyramid made on these bushings, the embedded ones themselves being torn in the dielectric insulator, to jointly determine a compact body resistant to different voltages mechanics to which it can be submitted etido.

To complement the description that will be carried out below and in order to help a better understanding of the characteristics of the invention, a single sheet is added to this specification, whose figures more easily demonstrate the innovations and advantages of the condenser that is the object of the study. present invention.

-4SUMMARY DESCRIPTION OF THE DRAWINGS

THE,

Figure 1 represents an exploded view of the condenser according to the present invention, representing in longitudinal section the two bushings and the dielectric insulator.

Figure 2 represents a longitudinal view of the fully assembled condenser with the bushings already made and embedded in the dielectric insulation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the attached figures, it can be seen how the capacitor according to the present invention is made up of four parts or bodies which are: the dielectric insulation (1), the bushings (2 and 3) and the screw or regulation shaft (4).

dielectric insulator (1) is an elongated body with a cylindrical configuration with an axial hole (5) and an external shoulder (6), this dielectric insulator (1) consisting of tetrafluoroethylene (teflon).

The bushings (2 and 3) are metallic and are mounted on the body (1) of the dielectric insulator, making the respective end of the bush (2) over the shoulder (6) of that body (1), while the bush (3) determines a kind of headboard with

a hole that has a thread (7) different from the thread (8) that has the adjusting screw or axis (4).

The assembly is carried out as shown in the attached figures, that is, with the bushings (2 and 3) mounted on the body of the dielectric insulator (1) and screwing the axis or the adjustment screw (4) into the threaded hole (7) of the bushing (3), the threaded part of that screw (4) being placed in the hole (5) of the dielectric insulator (1). The final fixation is carried out as a result of, on the bushings (2 and 3), torn inserts (9) with the shape of a quadrangular pyramid are made, which are embedded in the dielectric insulator (1), making the set a compact and resistant to the different mechanical stresses to which it can be subjected and to the retention action that the dielectric insulator (1) makes on the regulating screw or axis (4), the diameter of the hole (5) of that dielectric insulating body (1) being slight less than the outer diameter of the adjusting shaft or screw (4). The condenser assembly is also resistant to the voltage created by the dielectric insulator itself (1), which tends to force the regulating shaft or screw (4) to change its natural resting position, the dielectric insulator (1) acting as a brake. tensioner for that axis (4), in any position where it is.

thread pitch (7) of the bushing (3 and 8) of the screw or shaft (4) is different, thus achieving an excellent

-6 electrical connection, due to which the thread teeth (8) of that axis or screw (4) (of large pitch) will internally tear the thread teeth (7) (small pitch) of the bushing itself (3), being achieved thus the reliability of the adjustment.

Finally, using this screw or shaft (4), the capacitor capacity can be adjusted, since, based on a greater or lesser penetration of the threaded part, a greater or lesser distance from the metallic parts that make up the contacts is achieved electrical.

Claims (1)

Variable correction and / or tuning capacitor which, including some metal parts and a polytetrafluoroethylene dielectric insulator associated with them, is expected to be applied to tuned UHF filters and other frequency bands, characterized by the fact that the dielectric insulator (1 ) consist of a cylindrical body with an axial bearing hole (5), the metal parts being made up of a pair of bushings (2) and (3) mounted on that body (1) formed by the dielectric insulator, forming the bush ( 2) a top over an external recessed area (6) of said body (1), while the bushing (3) constitutes a head with a concentric hole provided with an internal thread (7) for the assembly of the respective axis or adjusting screw (4) whose thread pitch (8) is greater than the aforementioned thread pitch (7) of the bushing (3), with the particularity of fixing the bushes (2) and (3) to each other in the dielectric insulator body is rea use by means of embedded parts (9) that are driven into the lateral surface of this Ysolator body (1).