Title of Invention

"A RESISTIVE THERMOSTAT FOR ELECTRICAL MOTORS PROTECTION"

Abstract

It refers to a resistive thermostat for engines protection against electrical overcurrents and overtemperature, comprising a rectangular prismatic body (1), with a front side cover (2), and the back side face being provided with a comer lowering (3) having a spherical sector shape, as well as a pair of thin rectangular windows (4), said box (1) forming an enlargement of the front edge (5) for fitting of the cover (2), from which a lower tab (6) is appended, having a locating end cutout (7) with reference to two pins (8) of the three-pins connection plug; and further; and further, inside the prismatic box (1), corresponding to the pair of thin side windows (4), it is provided an end pair of metallic supports (9) and (10) for an electrical resistor (11), wherein one of such supports (9) projects a balanced metallic blade (12) outside the box, comprising one of its connection terminals, while in the other inner support (10) having a C shape, there attaches the end of the balanced bimetallic blade (13), immediately subjacent and connected in series with the electrical resistor (11) and with the lower opposite and free end having a contact button (movable) (14) facing another fixed button (15), the latter being mutual with the binding or inlet terminal (17), aligned with a corresponding orifice (18) provided on the cover surface (2), and receiving the third pin of the protector three-pins coupling plug concerned in the engine.

Full Text

Background of the invention Field of the invention The present invention relates to a resistive thermostat for electrical motors protection. From the essential point of view, such protectors comprise a thermostat metallic device, with the corresponding pair of electrical contacts, and thermally coupled with the motor it intends to protect, and also an electrical resistor heater connected in series to the motor in order to heat the first, the assembly actuation so that, in case of any motor overheating, the combines heating effect to the thermal coupling with the motor and the electrical resistor heating system is such that results in the heating of the thermostat metallic device, being enough to configurationally deform it and separate the protector electrical contacts, thus interrupting the electric power feeding to the motor. Concerning the real conceptive simplicity of such protectors, their currently existing constructive embodiments are extremely complex and expensive, including the unit external structure or body with multiple and varied cutouts, depressions, prominences and the like, such fact being also observed in the essential components themselves, also comprising a plurality of parts further affected by several details of tabs, holes, pins and the like, all such constructive complexity being naturally responsible for the major difficulties of its accomplishment and assembly, as well as increasing it cost, and further favoring the existence of disarrangements, lockings and other irregularities. Brief summary of the Invention The invention provides for a resistive thermostat for electrical motors, having at least one of an electrical resistor and a balanced bimetallic blade for protection against electrical overcurrents and overtemperature, comprising a three-pins connection plug that projects from said electrical motors body, a rectangular prismatic body (1), with a front side cover (2), said rectangular prismatic body having a back side face, opposite to said front side cover (2), and provided with a corner lowering (3) having a spherical sector shape, for supporting a user's finger when handling, said front side cover is also provided with a pair of thin rectangular windows (4) longitudinally aligned and proximate to the upper edge at said front side cover (2), said rectangular prismatic body (1) forming an enlargement of the front edge (5) of said front side cover (5) for a stable fitting of said cover (2), from which a lower tab (6) is appended, said lower tab having a locating end cutout (7) dimensioned with reference to two pins (8) of said three-pins connection plug. Yet another object of the invention is to provide an improved protection for high currents and temperatures in electrical motor using a resistive thermostat apparatus. Brief description of the drawings Fig. 1 is a front view of the concerned resistive thermostat for motors protection; Fig. 2 is a side and partially sectioned view of the same resistive thermostat of Fig. 1; Fig. 3 is an integral and front view of said resistive thermostat; Fig. 4 is a longitudinal section view as per A-A, indicated in Fig. 3; Fig. 5 is a cross-section view as per B-B, also indicated in Fig. 3; and Fig. 6 is an internal and front view of another embodiment of the concerned resistive thermostat. Detailed description of the accompanying drawings Referring to FIGS.l through 6, a resistive thermostat for motor protection against electrical over currents and over-temperature is shown comprising a rectangular primatic body or box 1, with a front side cover 2, both made of thermal and electrical insulating material (FIGS. 1 and 2), such body having the back side face (disposed opposite to cover 2) provided with a corner lowering 3 having a spherical sector shape, for supporting a user's finger when handling it to apply and remove it from the external surface of the engine (not shown), the box being also provided with a pair of thin rectangular windows 4 being longitudinally aligned and proximately to its upper edge. Further, said prismatic box 1, constituting the unit body, forms an enlargement of the front edge 5(FIGS.2 and 4) for a stable fitting of cover 2, from which a lower tab 6 is appended, having a locating end cutout 7 (FIG.l) with reference to two pins 8 of the three-pins connection plug which projects from the engine body. Advancing, and inside the prismatic body 1 of the concerned device (FIGS. 3 and 4), also corresponding to the aligned pair of thin windows 4 of it back side face, it is provided an end pair of metallic supports 9 and 10 for the electrical resistor 11, being dully positioned, wherein one of such supports 9 projects a balanced metallic blade 12 outside the box, comprising one of its connection terminals. In turn, the other inner support 10 for the electrical resistor 11, intentionally having a C shape, attaches one of the ends of a balanced bimetallic blade 13, arranged in immediate subjacency and connected in series with the electrical resistor 11 (FIG.3), and naturally with the lower opposite and free end having a contact button (movable) 14, facing another fixed button 15, the latter being mutual, by a connection metallic plate 16, with the binding or inlet terminal 17 being aligned with a corresponding orifice 18 provided on the cover surface 2, and receiving the third pin of the protector three-pins coupling plug concerned in the motor it is intended to. The operation of the protection resistive thermostat is virtually identical to other known protectors, this is, while the motor does not overheat due to eventual overcurrents or equivalents, it remains as illustrated (shown in full line in FIG. 3, that is, with the movable contact 14 and the fixed contact 15 closed, thus keeping the power feeding circuit for the motor. Continuing, in any eventual case wherein said motor overheating takes place, the thermal and electrical coupling heating effect, combined with the motor, by means of the electrical resistor 11 and the bimetallic blade 13, determines a naturally progressive heating of this latter, unit its resulting configurative deformation (shown in dotted line in FIG. 3), due to its balanced assembly, pushes away the movable contact 14 from the fixed contact 15 opening, the power feeding circuit for the motor and thus stopping its operation. It is important to note that the resistive thermostat, as described above, may be used in any condition of the motor, however, it is particularly useful for those working with a low current that would not be enough to deform the bimetallic blade 13, such case justifying the contribution of the electrical resistor 11, connected in series therewith. In cases where the motor works with a high electric current that is enough to deform the bimetallic blade 13, it is possible to dispense with the electrical resistor (FIG.6) and, in such case, the balanced metallic blade 12, consisting in one of the connection terminals of the protector, is derived and projected outside the C-shaped support 10 (to which the end of the bimetallic blade 13 is attached.) As discussed above, it is evident the extreme simplicity of the described resistive thermostat, relating to both its reduced number of component parts and their simplified configuration, being all aimed to reach the excellent working regularity, perfection and efficiency, as well as great facilities for its accomplishment, assembly and maintenance, further including an advantageous economic aspect and the total impossibility of disarrangement and other shortcomings. We claim 1. A resistive thermostat for electrical motors, having at least one of an electrical resistor and a balanced bimetallic blade for protection against electrical overcurrents and overtemperature, comprising a three-pins connection plug that projects from said electrical motors body, a rectangular prismatic body (1), with a front side cover (2), said rectangular prismatic body having a back side face, opposite to said front side cover (2), and provided with a corner lowering (3) having a spherical sector shape, for supporting a user's finger when handling, said front side cover is also provided with a pair of thin rectangular windows (4) longitudinally aligned and proximate to the upper edge at said front side cover (2), said rectangular prismatic body (1) forming an enlargement of the front edge (5) of said front side cover (5) for a stable fitting of said cover (2), from which a lower tab (6) is appended, said lower tab having a locating end cutout (7) dimensioned with reference to two pins (8) of said three-pins connection plug. 2. A resistive thermostat for electrical motors protection as claimed in claim 1, wherein said electrical resistor, and balanced bimetallic blade inside the prismatic body (1), correspond to said aligned pair of thin windows (4) of said back side face, said prismatic body is provided with an end pair of metallic supports (9) and (10) for said electrical resistor (11) so positioned, wherein one of said pair of metallic supports (9) projects a balanced metallic blade (12) outside the body having one of its connection terminals, while in the other inner support (10) having a C shape, attached to one of the ends of said balanced bimetallic blade (13), said balanced bimetallic blade is arranged in immediate subjacency and connected in series with said electrical resistor (ll),and naturally with a lower opposite and free end of said balanced bimetallic blade having a movable contact button (14), facing a fixed button (15), a metallic plate (16), a binding or inlet terminal, the fixed button being mutual, by said connection metallic plate (16), with said binding or inlet terminal (17) is aligned with a corresponding orifice (18) provided on the surface of said front side cover (2) and receiving a third pin of said three-pins connection plug. 3. A resistive thermostat for electrical motors protection substantially as herein described with reference to the accompanying drawings.

Documents:

692-del-2002-abstract.pdf

692-del-2002-claims.pdf

692-del-2002-complete specification (granted).pdf

692-del-2002-correspondence-others.pdf

692-del-2002-correspondence-po.pdf

692-del-2002-description (complete).pdf

692-del-2002-drawings.pdf

692-del-2002-form-1.pdf

692-del-2002-form-19.pdf

692-del-2002-form-2.pdf

692-del-2002-form-3.pdf

692-del-2002-pa.pdf

692-del-2002-petition-137.pdf

abstract.jpg