UA80003C2 - Universal field lengthener - Google Patents

Abstract

A universal field lengthener includes an insulated body and a cover, which has holes for a plug. Power electrical pathways are fixed inside the body. Contact sockets are connected to electrical pathways by means of flexible conductors, the inner diameter of contact socket being equal to the max. diameter of plug pin. These contact sockets are jointed non-rigidly on moveable spring-loaded plates. Plates move in transverse direction relatively to pins location by means of spring pressure, pressing socket to pin. Shatters are affixed at these plates near contacts socket. The invention provides reliable and stable electrical contact "pin-socket" independently from the plug pin diameter, minimum deterioration of pins and socket surface at multicontact connection of electrical energy consumers to the lengthener.

Description

Description of the invention

The invention relates to electrical appliances, more precisely to extension cords, i.e. to multiple portable 2 sockets. Both single and multi-seat extension cords are widely used in everyday life and in production, which allow several electricity consumers to be connected to them using electric plugs at the same time 1), while the total power of consumers at the same time, as a rule, does not exceed 1.3 kW at 2208 voltage.

The most vulnerable point of such extension cords is the contact pair: plug pin - socket extension cord.

Sockets in extension cords are made of elastic material, as a rule, in the form of a cylindrical bracket with a 70 flanged part at the entrance of the socket, as in (21) and (ZI.

For a good electrical contact, the sockets of the extension cord try to ensure that the plug of the consumer of electricity enters the contact element rigidly, and at the same time, after multiple power-ups of the plug, the mechanical and, accordingly, the electrical contact weakens due to the wear of the connecting surfaces of the pin and the socket, and, therefore, reduction of contact pressure. A decrease in the contact pressure leads to an increase in the electrical resistance to the passage of current that is consumed.

This limits, firstly, the maximum amount of current through the contact pair (the contact pair begins to overheat due to an increase in contact resistance), and, secondly, the term of use of the extension cord and plug is limited. This especially applies to cases when they want to make extension sockets universal, so that they can be connected to them as plugs of the former Soviet Union standard GOST 7396.1 (254.Ohm), so-called European plugs, which have a slightly larger pin diameter (24.8 mm). At the same time, the use of a Euro plug for extension cords designed for a pin diameter of 4.0 mm quickly disables the sockets of the extension cord, because the deformation of the socket material exceeds the limit of their elasticity, and this happens especially quickly with significant consumption currents. On the other hand, if the extension cord is designed for a Euro plug, then connecting it to the plugs of the old GOST also causes the contact sockets to fail quite quickly, since the weakened mechanical pressure between the pin and the socket leads to an increase in the electrical resistance of the contact and Go) in accordance with the overheating of the contact plug-socket pairs.

The purpose of the invention is to develop the design of the contact pair and, accordingly, the extension cord in such a way as to get rid of the specified defects, namely, that the pin-socket contact is reliable for both types of plugs and that the wear of the specified elements is minimal when repeatedly connecting electricity consumers to the extension cord. The basis of the 3o design is the use of a spring-loaded socket, the inner diameter of which is equal to the largest diameter (ав) of the pins, which can presumably be used when connecting electricity consumers to the extension cord.

The closest analog (prototype) to the proposed design is the extension cord shown in (1) with the contact sockets shown in (21). It is three-seater, has a case with an upper cover, in which there are holes for inserting (ав) the plugs of the plug, and these holes can overlap with curtains that prevent foreign objects from entering the housing when the plug is not connected to the extension cord.

The design of the proposed extension cord is outlined in the drawings, and a description of its features is given in the following text, where the same designations in the references refer to similar elements. Fig. 1, 2 show two projections of the design of the extension cord: Fig. 1 - cross-section of the box, Fig. 2 - top view of the box with the cover removed. One section of the extension cord is shown, the other sections (for the multi-seater version with the extension cord) are structurally arranged similarly. Fig. 3 shows a view of the end of the box from the inside.

Fig. 4 is a section of the pin-socket contact pair to illustrate a possible design solution for fixing the required height of the socket attachment on the movable bar. bo 15 The design consists of a plastic casing of the box 1, on the bottom of which, on a small rise 2, two power current leads (buses) C are fixed with the help of self-tapping screws 4. Next to the self-tapping screws on the same (а) bent petals of the bus, threaded holes 5 are provided for fastening the power cable extension cord, which can enter the box through hole 6 in it. Current leads Z are separated from each other by a plastic partition 7, which is a single unit with the body of the box 1. From the power buses Z by means of a stranded conductor 8, the voltage (c) 50 is applied to the contact group consisting of a contact socket 9, which sits loosely on the movable strip c" of the 10th contact pin 11 of the electric plug (the plug is not shown, only its pins are visible in the figure). On the movable bar 10, a plastic holder 12 of a spring 13 is pressed on one side, and this holder simultaneously acts as a curtain that closes the inlet of the extension cord when the plug is not inserted into the extension cord, and a plastic button 14 is pressed on the opposite side of the bar. 59 Second pin-socket contact pair of the extension cord, as can be seen, is arranged in the same way as just described, only

GF) it is oriented as a mirror relative to the axis of the extension. The entire contact group, i.e. the movable strip with the contact 7 pair together with the plastic spring holder and the button slide on the lower plane along the surfaces 15 and 16, and the upper plane, which prevents the contact group from sliding upwards, is formed by the cover 17, which covers the case. How the landing height of the contact socket is limited relative to the movable bar in which it sits 60 can be seen in Fig.4. The socket, which is stamped from the strip and has a flange of the upper edge 18 (for a good entry of the pin into the socket), is inserted loosely into the movable bar 10 and is fixed at the required height using a cutout 19 in two ears, to which a flexible wire 8 is attached using a screw 20 with with a nut

The essence of the invention is that in the pin-socket contact pair, a predictable, stable and constant pressure of the socket on the pin is provided, regardless of the number of insertions of the plug into the socket. The constancy of the contact pressure 65 is ensured by the action of the spring 13, which is compressed before inserting the fork by the force of the operator’s hand by pressing the buttons 14. When the fork pins are fully inserted into the contact sockets, the lower part of the pin additionally contacts the rigid power bus C and thus the total contact area is determined by the length of the line of pressing the socket to the pin and the line of pressing the pin to the power bus, which can add up to the length of the linear contact of about 10 mm for standard forks.

The transient resistance of the contact pair according to (4) is inversely proportional to the contact pressure:

Rer.- sov. (NEV n) where c is a coefficient that depends on the cleanliness of the surface and is equal to 72; p - specific electrical resistance of the contact material, Ohm-cm;

No - surface hardness of the contact material according to Brinell, kH/mm;

Rk - contact pressure, kH; c - the coefficient for point (as in our case) contacting is equal to "0.33. t It can be seen from relation (1) that at a constant contact pressure P; the transition resistance Claire will be stable, which means that the socket will not spark and overheat, say, when the position of the extension cord changes, its vibration, etc.

In addition, it can be seen that the Claire value is greatly influenced by the specific resistance of the contact material p. In our case, the contact socket does not necessarily need to be made of a spring material with a sufficiently high specific resistance, as is the case in the prototype, on the contrary, the socket material can be freely choose from the most conductive and softest possible material (the softer the material, the less Nb and, accordingly, Ker.) Among which copper is the best.

The free, non-rigid fit of the contact socket 9 on the movable bar 10 ensures the reliability of pressing the socket to the pin along the entire line of their connection, because even if the pin is slightly skewed relative to the line of its insertion, the contact socket will still fit it tightly due to the force of the spring. It is important that cm current consumers can have plugs with a different pin diameter standard, but the electrical contact will be (3 reliable, moreover, even if it is just a part of the wire cleaned of insulation (as it sometimes happens in emergency situations in production) is still necessary contact will be provided. This fact is of the utmost importance for the potential consumer of the proposed device

It should also be noted that the design protects the entrance holes of the extension cord from unauthorized access with the help of very reliable, strong insulating curtains, which are tightly seated on the movable bar. (av)

A feature of the design is also that each contact socket is reliably connected to the power supply by an individual flexible wire, which ensures the possibility of long-term and trouble-free operation of the extension cord. (av)

The device works as follows. If it is necessary to connect the energy consumer to the extension cord, the operator presses his fingers on the buttons located opposite each other, at the same time the curtains are moved beyond the entrance holes of the extension cord, and their place under the entrance holes is occupied by contact sockets, where the plug of the consumer is inserted to the end. After that, the buttons are released.

Literature: « du 1. Rosenthal Z.S. Electrical installation device. M. Znergoatomizdat. 1989. Page 146. - 2. Patent KO 2042239 C1 M.cl. NOTE K25/00. 1993. p. 3. Patent KO 2037240 C1 M.cl. NOTE K25/00. 1993. :z» 4. Lyarsky V.F., Muradyan O.B. Electrical connectors. Directory. M. Radio and communication. 1988.

Claims (1)

The formula of the invention (ee) ("in Universal field extension cord, containing an insulated case and a cover with holes for a plug in it, contact sockets, curtains mounted in the case, which is distinguished by the fact that inside the case, power leads are attached to current leads, to which with the help of flexible contact sockets are connected to the wires, the inner diameter of which (in 50 is equal to the largest diameter of the plug pins, these contact sockets are fixed loosely on movable spring-loaded bars that move with the help of spring force in the direction transverse to the orientation of the plug pins, pressing the socket to the pin, while the curtains are fixed on the same bars next to the contact sockets. F) name) 60 b5