Abstract
A switch unit, preferably implementing a circuit breaker, includes a contact slide unit formed by a contact slide, a fixed contact piece and a moveable contact piece), and a short-circuit release that acts to displace the moveable contact piece by means of a tappet in the event of a short-circuit. A moveable braking device is configured and arranged such that, following circuit opening displacement of the moveable contact piece in response to a short-circuit, the moveable brake device dampens the return, rebound movement of the moveable contact piece to reclose the circuit.
Claims
1. A switch unit, comprising: a contact slide unit, comprising a contact slide, a fixed contact piece and a moveable contact piece; a tappet; a short circuit release that, in response to a short-circuit condition, effects movement of the tappet to cause movement of the moveable contact piece in a first direction to disengage the moveable contact piece from the fixed contact piece to provide an open condition of the switch unit, and wherein the moveable contact piece is arranged for return movement in a second direction into re-engagement with the fixed contact piece to provide a closed condition of the switch unit; a moveable braking device constructed so that, during the return movement of the moveable contact piece the moveable braking device dampens the return movement of the moveable contact piece; and a guide element arranged to guide the movement of the moveable contact piece along an exterior of the guide element, the moveable contact piece surrounding the guide element and having an opening through which the guide element is routed.
2. The switch unit of claim 1, wherein the moveable braking device comprises a mass disposed above the moveable contact piece and at an upper end of the guide element.
3. The switch unit of claim 2, wherein the mass of the moveable braking device comprises a flat punched metal element produced by die-stamping.
4. The switch unit of claim 1, wherein the moveable braking device comprises a double mass arranged above and below the moveable contact piece and proximate two opposite end regions of the guiding element.
5. The switch unit of claim 1, wherein the moveable braking device is arranged on the tappet.
6. The switch unit of claim 5, wherein the moveable braking device comprises a tubular extension that surrounds the tappet.
7. The switch unit of claim 1, wherein the switch unit comprises a circuit breaker.
8. The switch unit of claim 1, further comprising a spring for driving the return movement of the moveable contact piece in the second direction.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the drawings:
(2) FIG. 1 is a schematic cross-sectional representation of a first exemplary embodiment of a switch unit according to the invention, with a contact slide and a short-circuit release, and including a braking device in the form of an additional mass, depicted in the closed state;
(3) FIG. 2 is a schematic cross-sectional representation of the embodiment shown in FIG. 1, in the event of a short-circuit;
(4) FIG. 3 is a schematic cross-sectional representation of the embodiment shown in FIGS. 1 and 2, during the reflex bridging action of the moveable contact piece on the braking device;
(5) FIG. 4 is a schematic cross-sectional representation of the embodiment shown in FIGS. 1 to 3, with a contact position maintained in the open position by the latching mechanism;
(6) FIG. 5 is a schematic cross-sectional representation of a second embodiment of a switch unit according to the invention, with a contact slide and a short-circuit release, and including a braking device according in the form of a double mass, in the closed state;
(7) FIG. 6 is a schematic cross-sectional representation of the embodiment shown in FIG. 5, in the event of a short-circuit;
(8) FIG. 7 is a schematic cross-sectional representation of the embodiment shown in FIGS. 5 and 6 in the event of a short-circuit, including the housing limit stop of the moveable contact piece;
(9) FIG. 8 is a schematic cross-sectional representation of the embodiment shown in FIGS. 5 to 7, during the reflex bridging action of the moveable contact piece on the braking device;
(10) FIG. 9 is a schematic cross-sectional representation of the embodiment shown in FIGS. 5 to 8, with a contact position maintained in the open position by the latching mechanism;
(11) FIG. 10 is a schematic cross-sectional representation of a third embodiment of a switch unit according to the invention, with a contact slide and a short-circuit release, and including a braking device in the form of a tubular extension of the tappet of the short-circuit release, in the closed state;
(12) FIG. 11 is a schematic cross-sectional representation of the embodiment shown in FIG. 10, in the event of a short-circuit;
(13) FIG. 12 is a cross-sectional representation of the embodiment shown in FIGS. 10 and 11, during the reflex bridging action of the moveable contact piece on the brake device;
(14) FIG. 13 is a cross-sectional representation of the embodiment shown in FIGS. 10 to 12, with a contact position maintained in the open position by the latching mechanism;
(15) FIG. 14 is a time vs. displacement graph for the moveable contact piece in a prior art construction;
(16) FIG. 15 is a time vs. displacement graph for embodiments of the present invention having an additional mass as a braking device, or with a tubular extension of the tappet as a braking device for the moveable contact piece;
(17) FIG. 16 is a time vs. displacement graph for an embodiment of the invention that includes a double mass as a braking device for the moveable contact piece; and
(18) FIG. 17 is an elevated perspective view of an embodiment of a switch unit according to the invention with a short-circuit release and a braking device in the form of a mass formed of a flat punched metal element produced by die-stamping.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(19) FIG. 1 depicts a first embodiment of a switch unit constructed in accordance with the invention, having a contact slide unit comprising a contact slide 1, a fixed contact piece 2, and a moveable contact piece 3, and a short-circuit release 4 that acts in the event of a short circuit upon the moveable contact piece 3 by means of a tappet 5. The moveable contact piece 3 is provided with an opening 6, through which a guide element 7 is routed. Above the moveable contact piece 3, the guide element 7 is configured with a mass 8 that is arranged on the moveable contact piece 3 such that, in the event of a short-circuit, it separates the moveable contact piece 3 from the fixed contact piece 2, if the tappet 5 engages with the mass 8.
(20) The center of gravity of the mass 8 lies above the moveable contact piece 3. Below moveable contact piece 3, the guide element 7 may be guided either in the housing 9 or in the contact slide 1, or in a combination of housing 9 and contact slide 1.
(21) FIG. 1 also depicts the disengageable mechanical kinematic chain in the form of a latching mechanism 10. The function of latching mechanism 10 is permanent maintenance of the contact bridge in the open position in the event of tripping.
(22) In FIG. 2, the contact slide unit of FIG. 1 is shown in the event of tripping. As there seen, the tappet 5 engages with the mass 8 of the guide element 7, such that the guide element 7 retracts into the guide of housing 9 thereby separating moveable contact piece 3 from fixed contact piece 2.
(23) FIG. 3 depicts the embodiment shown in FIGS. 1 2 during the reflex bridging action of moveable contact piece 3 on the brake device, configured in the form of the mass 8 on guide element 7.
(24) FIG. 4 shows the embodiment of FIGS. 1 to 3 in which the contact bridge is maintained in the open position by latching mechanism 10.
(25) In FIG. 5, a further, second embodiment of a switch unit constructed in accordance with the invention with a contact slide 1 and a short-circuit release 4, includes a brake device in the form of a double mass 11, shown in the closed state. As in the first embodiment of FIGS. 1 to 4, the contact slide unit comprises a contact slide 1, a fixed contact piece and a moveable contact piece 2, 3, and a short-circuit release 4 that acts in the event of a short circuit upon moveable contact piece 3 by means of a tappet 5. As in the first embodiment, the moveable contact piece 3 is also provided with an opening 6, through which a guide element 12 is routed. Above and below moveable contact piece 3, the guide element 12 is configured at its respective ends with a mass, which in this second embodiment implements the brake device in the form of a double mass 11. The mass above moveable contact piece 3 is configured such that, in the event of a short-circuit, it separates moveable contact piece 3 from fixed contact piece 2 if tappet 5 engages with the mass. The mass below moveable contact piece 3 is configured such that, in the event of tripping, it limits the movement of moveable contact piece 3. Accordingly, the guide for guide element 12 with double mass 11 in housing 9 is adapted to accommodate the mass below the moveable contact piece 3. FIG. 5 also includes the disengageable mechanical kinematic chain in the form of a latching mechanism 10. The function of latching mechanism 10 is permanent maintenance of the contact bridge in the open position in the event of tripping.
(26) In FIG. 6, the contact slide unit of FIG. 5 is shown in the event of tripping. In that case, tappet 5 engages with the double mass 11 of guide element 12, such that guide element 12 retracts into the guide of housing 9, thereby separating moveable contact piece 3 from fixed contact piece 2.
(27) FIG. 7 depicts the second embodiment of FIGS. 5 and 6 in the event of a short-circuit, whereby the movements of moveable contact piece 3 are limited firstly by the housing limit stop and secondly by the double mass 11 below moveable contact piece 3.
(28) FIG. 8 shows the second embodiment of FIGS. 5 to 7 during the reflex bridging action of moveable contact piece 3 on the brake, configured in the form of a double mass 11 on guide element 12.
(29) In FIG. 9 of the embodiment depicted in FIGS. 5 to 8, the latching mechanism 10 maintains the contact bridge in the open position.
(30) FIG. 10 depicts a third embodiment of a switch unit in accordance with the invention that includes a contact slide 1 and a short-circuit release 4, and a brake device in the form of a tubular extension of the tappet 5 of the short-circuit release, shown in the closed state. As in the first and second above described embodiments, the contact slide unit comprises a contact slide 1, a fixed contact piece 2, a moveable contact piece 3, and a short-circuit release 4 that, in the event of a short-circuit, acts upon moveable contact piece 3 by means of a tappet 5. In this third embodiment, the brake device is configured as a tubular extension 13 that surrounds the end of tappet 5. FIG. 10 also depicts a disengageable mechanical kinematic chain in the form of a latching mechanism 10. The function of latching mechanism 10 is permanent maintenance of the contact bridge in the open position in the event of tripping.
(31) In FIG. 11, the contact slide unit of FIG. 10 is shown in the event of tripping. In that case, the tappet 5, including tubular extension 13, engages moveable contact piece 3 thereby separating moveable contact piece 3 from fixed contact piece 2.
(32) FIG. 12 shows the third embodiment of FIGS. 10 and 11 during the reflex bridging action of moveable contact piece 3 on the brake device, configured in the form of the tubular extension 13 on tappet 5.
(33) FIG. 13 depicts the third embodiment of FIGS. 10 to 12 with latching mechanism 10 maintaining the contact bridge in the open position.
(34) FIG. 14 is a time vs. displacement graph for a moveable contact piece in accord with the prior art, and thus without a brake device of the present invention. As there seen, the time required for movement of the moveable contact piece in the direction of the housing limit stop is equal to that required for the return movement into reengagement with the fixed contact piece, i.e. the moveable contact piece executes this movement unbraked.
(35) The time vs. displacement graph of FIG. 15 is depicted for an embodiment of the switch unit constructed in accordance with the invention, which includes an additional mass as a braking device or a tubular extension on the tappet as a braking device for the moveable contact piece. As there shown, the path from initial contact engagement S.sub.0 to the housing limit stop S.sub.2 corresponds to the first part of the profile shown in FIG. 14. However, the subsequent path from the housing limit stop S.sub.2 in the return direction toward contact engagement S.sub.0 is different. In this case, there is a collision at point S.sub.1 and, accordingly, an exchange of energy between the braking device and the moveable contact piece. The resulting additional interval or gain in time is depicted in the graph as the time interval t.sub.2. As a result of the time delay generated by the braking device, the action of the latching mechanism is ensured.
(36) FIG. 16 shows a time vs. displacement graph for the embodiment of the present invention that includes a double mass as the braking device for the moveable contact piece. In contrast to the graph shown in FIG. 15, there is an even longer time delay, identified in the graph by the interval t.sub.3, associated with the two-fold collision between the upper mass and the moveable contact piece, and between the lower mass and the moveable contact piece. Here again, as a result of this time delay, the action of the latching mechanism is ensured.
(37) FIG. 17 shows a another switch unit constructed in accordance with the invention, having a fixed contact piece 2, a moveable contact piece 3, and a short-circuit release 4 that acts on moveable contact piece 3 by means of a tappet 5 in the event of a short-circuit. The guide element 7 is arranged above moveable contact piece 3 and is configured with a mass 8 on moveable contact piece 3 such that, in the event of a short-circuit, moveable contact piece 3 is separated from fixed contact piece 2 if tappet 5 engages with mass 8. In this further embodiment, the mass 8 is configured as a flat punched metal element produced by die-stamping.
(38) The present invention is characterized in that, by the positioning of at least one additional mass that serves as braking device, an exchange of energy results from the collision of two bodies, thereby reducing the moving speed of the moveable contact piece. The additional masses for the braking device, in at least two embodiments herein disclosed, are arranged on the guide element that guides the moveable contact piece. By this arrangement, the guide element fulfills a dual function. Firstly, it acts as a braking device that reduces the speed of the rebounding moveable contact piece in the event of tripping. Secondly, the guide element guides the moveable contact piece such that any rotation of the latter due to the delivery of a high impulse of motion can be reliably prevented. Accordingly, even in the event of high short-circuit currents, a switch unit constructed in accordance with the present invention permits reliable execution of the chronological sequence of contact-opening mechanisms.
