Transformer

Abstract: A transformer or autotransformer having a high-level electrical insulation, of comparatively simplified construction, with incorporated improved terminal blocks and pre-arranged for different types of positioning.

Description: The invention relates to a transformer or autotransformer having a high-level electrical insulation, of comparatively simplified construction. From US-A-4 671 697 a transformer is known comprising a casing provided with apertured feet, in which said feet protrude from the bottom of said transformer, so as to define therewith a portal-like structure, at least one pair of said feet being provided on their inner sides with recesses, cooperating with one edge of a mounting channel-like structure having an "omega" or other profile, the bottom of the transformer being further provided at an intermediate position with transversal guide having mounted thereon a spring-operated latch co-operating with the opposite of said channel, so as to firmly lock the transformer, said guide having an inverted T profile and the latch which is slidably mounted on said guide has a corresponding C profile and is provided with an extension fitting in a longitudinal recess of said guide; a longitudinal slit for the introduction of a spring; and rear end-of-stroke stop. From GB-A-0 872 883 a transformer is known of the type comprising an electrical insulating casing made of plastics material provided with slotted feet for securing the transformer in place. According to the present invention a transformer is provided, of the type comprising an integral casing (5) of plastic material, the transformer being provided at its base, preferably at the corner regions of the core (4), with feet (6) protruding from the bottom of the casing, said feet having apertures for securing the transformer in place, at least one pair of said feet being provided co-planary with the bottom of the casing with recesses (8) cooperating with a first edge of a channel-like structure (9) having an "omega" or similar profile, a guide (10) being formed integrally at the bottom of the casing, the guide being transversally oriented with respect to the large surface of the transformer core and at an intermediate position with respect to the feet, said guide having in cross section a substantially inverted T-shaped profile and having a longitudinal recess (11), a spring operated latch (12) with a substantially C-shaped profile being slidably mounted on the guide and cooperating with the second edge of the channel-like structure for fixing the transformer on said channel-like structure, the latch being provided with a stop (212) cooperating with a protruding edge of the guide oriented transversally with respect to the longitudinal recess, with an extension (112) fitting in the longitudinal recess of the guide, and with a longitudinal slit (14) for the introduction of a spring (13), the transformer being characterized by the fact that its casing is acoustical insulating and comprises cooling fins (105), and that the said latch is further provided, at its side cooperating with the channel-like structure, with one or more teeth (412) having an inclined side for self-adaptation to the thickness of the second edge of the mounting channel. Further characteristics of the transformer according to the invention and the advantages resulting therefrom will become apparent from the following description, made with reference to the Figures of the accompanying two sheets of drawings, wherein: Figure 1 is a perspective view of the transformer; Figure 2 is a bottom plan view of the transformer; Figure 3 shows the lower portion of the transformer, as seen from the section line IV-IV of Figure 3; Figure 4 is a side elevational and partly sectional view of the transformer, as seen from the line V-V of Figure 1; As shown in the drawings, the transformer according to the invention comprises an insulating casing 5 made of plastics material having antifire characteristics, good electrical insulation features and good characteristics of resistance to chemical-physical stresses which encloses also the transformer bobin and which has the following functions: it improves the electrical insulation of the transformer up to levels never found in transformers of conventional type; it increases the heat-exchange surface which is licked by the ambient air, by providing said casing with suitable fins of the type indicated, for example, at 105 in Figures 3 to 5; it forms at the base of the transformer, preferably at the corner regions of one of the larger sides of the yoke 4, apertured or channelled feet 6 (Figure 1) to be used for securing the transformer in place by means of screws or a mounting guide; it defines around the tongues 3, respective sets of housings 7-107 to be used for the formation of terminal blocks. From Figures 1, 2 and 4 it will be noted that the feet 6 protrude for an equal extent from the bottom of the transformer so as to define therewith a portal-like profile (Figure 4). The feet which are located at one side of the transformer are provided - in the inner side thereof and co-planarly with the bottom of the casing 5 - with respective recesses 8 which permit the transformer to be overhangingly mounted on a DIN guide channel 9 having an "omega" profile (Figure 3), of the type which is used commonly with electrical switchboards for supporting terminal blocks, remote-control switches and other components. The recesses 8 co-operate with the upper edge of the channel 9, whereby the transformer is substantially suspended from said edge. The positioning of the transformer on the channel 9 is, however, stabilized by a latch device arranged intermediately of the bottom of the casing 5 and co-operating with the lower side of said channel. During the formation of the casing 5, in fact, a guide 10 with a substantially inverted "T"-shaped profile, having a longitudinal recess 11, is formed integrally at the bottom of the transformer at an intermediate position and with a transverse orientation. Said guide mounts a latch device 12 of substantially C-shaped profile, provided with an extension 112 which fits into said recess 11 of said guide and which will be acted upon by an opposing spring 13 which may be introduced into said recess 11 through a window 14 provided longitudinally in said latch device, the latter being also provided with: a rear stop 212 co-operating with the outer end of the guide 10 at the end of its stroke; an external extension 312 with a slot 15 for insertion of a screw-driver or other means to operate the latch in contrast against the action of the respective spring 13; one or more front teeth 412, preferably with an inclined front side, adapted to pinch the lower edge of the channel 9 and capable of self-adaptation to the thickness of said edge. The guide 10 is tapered at the initial part thereof, as indicated at 16 in Figure 2, to permit the extension 112 of the latch to enter perpendicularly the recess 11 in said guide. The advantages of the two different possibilities of mounting the transformer are apparent and result from the presence of the slotted or apertured feet 6 and from the characteristics described above with reference to Figure 3. With reference to Figures 1 and 4, it will be noted that the housings 7-107 comprise small substantially parallelepipedal boxes B-B1, opened at one end whereinto a respective, preferably metallic slider 17 is inserted to embrace the tongue 3 or 103, said slider having in the top thereof a threaded hole co-operating with a screw 18 having a head 118 with a slot for a screwdriver, which rotatably engages, without protruding therefrom, a through-hole 19 in the top of each box B-B1, said head being provided with a collar 218 abutting against said top wall of the boxes. The screw 18, moreover, is of such a length as to engage, at its lower end, the tongue 3 or 103. By turning the screw 18 by means of a screwdriver inserted into the hole 19, said screw causes the slider 17 to be lifted or lowered. The wire to be electrically connected to the tongue 3 or 103 is disposed under said tongue and is clamped between said tongue and the bottom wall of the slider 17.

Claims: A transformer comprising an integral casing (5) of plastic material, the transformer being provided at its base, preferably at the corner regions of the core (4), with feet (6) protruding from the bottom of the casing, said feet having apertures for securing the transformer in place, at least one pair of said feet being provided co-planary with the bottom of the casing with recesses (8) cooperating with a first edge of a channel-like structure (9) having an "omega" or similar profile, a guide (10) being formed integrally at the bottom of the casing, the guide being transversally oriented with respect to the large surface of the transformer core and at an intermediate position with respect to the feet, said guide having in cross section a substantially inverted T-shaped profile and having a longitudinal recess (11), a spring operated latch (12) with a substantially C-shaped profile being slidably mounted on the guide and cooperating with the second edge of the channel-like structure for fixing the transformer on said channel-like structure, the latch being provided with a stop (212) cooperating with a protruding edge of the guide oriented transversally with respect to the longitudinal recess, with an extension (112) fitting in the longitudinal recess of the guide, and with a longitudinal slit (14) for the introduction of a spring (13), the transformer being characterized by the fact that its casing is acoustical insulating and comprises cooling fins (105), and that the said latch is further provided, at its side cooperating with the channel-like structure, with one or more teeth (412) having an inclined side for self-adaptation to the thickness of the second edge of the mounting channel.

Inventors: ZUPPIROLI GIUSEPPE, ZUPPIROLI, GIUSEPPE
Applicants: BERTOLDO & C SRL, BERTOLDO & C. S.R.L.
Application year: 1990
Main classification: H01F27
IPC codes: H01F27, H01F5