A SWITCHING ARRANGEMENT COMPRISING A CONTACT-BEARING LAMINA APT TO BE INCLINED TOWARDS ONE OR MORE POSITIONS

Abstract: An electrical switching arrangement comprising an electrical conductive plate (P) resting on a spring (M) which in turn is supported by a stationary base (B), said plate bearing at least one movable contact (C3 or C4), and at least one lower stationary contact (C1 or C2) apt to engage at least said movable contact (C3 or C4), and at least one push button for applying an operating force (F) to said plate (P), one of which movable contacts (C3 or C4), as a result of the lowering of the push button for applying force (F), engaging one of said stationary contacts (C1 or C2), which operating push button presses said plate, bearing at least one movable contact (C3 or C4) at a position between a point of substantial alignment with said movable contact (C3 or C4) and any point whatsoever between said movable contact and the spring (M). A switch carried out in accordance with said switching arrangement.

Description: TITLE OF INVENTION A SWITCHING ARRANGEMENT COMPRISING A CONTACT-BEARING LAMINA APT TO BE INCLINED TOWARDS ONE OR MORE POSITIONS Technical Field The present invention relates to a two or three position switch, in particular for controlling the two speeds of a number of different apparatus. 5 The invention finds particular application in two or three position switches, for example in a pendant pushbutton for controlling two different functions of an electric motor, especially for controlling an overhead travelling crane either in 0 one direction or in an opposite direction, for raising and lowering a load, and so forth. Background Art Conventional prior switches for the above mentioned applications are invariably based on one 5 and the same principle, i.e. that of providing a bridge consisting of a metal plate having two contacts which engage two other stationary contacts thereby creating an electrical connection between them in order to actuate a relay. If then an 0 electric motor is to be controlled in order for it to provide two different speeds, then the number of the already numerous components is doubled. Disclosure of the Invention Object of the invention is to provide a switch having a novel structure and arrangement of its components in such a manner as to drastically reduce be it the number of said components, be it the time for producing, assembling and wiring said switch. Another object is to provide a novel switch maintaining the said advantages and features which can easily be employed to provide a two-position and tw-way switch, having either one or two control pushbuttons, in which each pushbutton can controll, for example, two relays connected to a two-speed electric motor. A further object of the invention is to provide such a switch having a very simple and reliable structure, which can be used both in industrial and in civil applications. Brief Description of Drawings The above mentiond objects are all achieved by a switch according to the present invention, which will be described hereinafter with reference to the accompanying drawings, wherein: Figure 1 is a schematic view of the novel operating principle on which is based the novel switching arrangement according to the instant invention for commutating a switch having two sequential closed conditions of its contacts; Figures 2A, 2B and 2C are, respectively, a top plan view, a front elevation view and a side elevation view showing schematically the main construction of a double switching arrangement, having a biassing spring as shown in Figures 2B and 2C , for switching from an inactive or open condition to two active or closed conditions of different contacts, in accordance with the present invention; Figure 3 is a front elevation view illustrating the double switching arrangement of Figures 2, in its inactive or open condition, the biassing spring not being shown in order to allow all the contacts to be seen; Figure 4 is a front elevation view illustrating the double switching arrangement of Figure 3, in its first actuating condition, according to the present invention; Figure 5 is a front elevation view illustrating the double switching arrangement of Figure 3, in its second actuating condition, according to the present invention; Figure 6 is a side elevation view illustrating the double switching arrangement of Figure 3, in its inactive or open condition; Figure 7 is a side elevation view illustrating the double switching arrangement of Figure 4, in its first actuating condition, according to the present invention; Figure 8 is a side elevation view illustrating the double switching system according to Figure 5, in its second actuating condition, according to the present invention; Figure 9 illustrates an electric locking function should two control pushbuttons, controlling two opposite functions, be pressed simultaneously; Figures 10A to 10D illustrate an application of the switching arrangement to a safety switch in which the deactivation of an apparatus is achieved be it by releasing the control pushbutton, be it by applying an anomalous pressure to said control pushbutton; Figures 11 and 12 are exploded perspective views, from the top and bottom, respectively, of a particular constructional embodiment of the switch as schematically shown in Figures 3 to 8; Figure 13 is a top plan view of a preferred embodiment of a switch made according to the arrangement shown in Figures 3 to 9; Figures 14A and 14B are cross-sectional views, taken along the lines V-V and R-R, respectively, of Figure 13, of the switch in its open condition corresponding to Figures 3 and 6; Figures 15A and 15B are cross-sectional views, taken along the lines V-V and R-R, respectively, of Figure 13, of the switch in the first actuating position corresponding to Figures 4 and 7; and Figures 16A and 16B are cross-sectional views, taken along the lines V-V and R-R, respectively, of Figure 13, of the switch in its second actuating position corresponding to Figures 5 and 8. With reference to Figure 1, the novel basic concept of a switching arrangement providing the possibility of switching at two sequential connecting positions relying on a single pushbutton which can be lowered to two different lowered positions will be disclosed hereinafter. Figure 1 schematically shows a contact-bearing plate P made of an electrically conductive material and having a pentagonal shape, to which plate a power supply conductor is directly coupled, and which bears two movable contacts C3, C4, on its bottom surface. Said plate P is suported by a spring M which at its bottom end is coupled to a fixed base B. As a force F is applied on the plate P at a point between the movable contact C3 and the spring, the plate P will be tilted leftwards to bring the movable contact C3 to engage with the stationary contact Cl, thereby providing an electric contact between the conductor A and stationary contact Cl which will be suitably coupled to an apparatus to be controlled. By increasing the value of the force F, the mentioned contacts C3 and Cl will remain engaged one with the other and, moreover, also the contacts C4 and C2 remain engaged, since the right end of said plate will also be lowered to such an extent so as to bring the movable contact C4 in engagement with the stationary contact C2 suitably connected to a second apparatus. At this point it becomes evident that the herein schematically disclosed arrangement is suitable for numerous applications, both of the industrial and civil type, for example for making switches for controlling two-speed motors in their two rotational directions. Figures 2A, 2B and 2C show a subsequent development step of a switch of this type, again schematically shown for better illustrating its operating principle. Differently from what is illustrated in Figure 1, here is shown a plate P also of pentagonal shape, which can be operated by two pushbuttons PI and P2, on which plate there are provided two top stationay contacts CF1 and CF3 which are electrically connected by a conductor K, and under which plate P there are provided three bottom stationary contacts CF4, CF6, CF5 substantially arranged at the vertices of a triangle. On and under said plate P are moreover provided double movable contacts CMl and CM3 and a single movable contact CM2 (see Figure 2C), at a position vertically aligned with the respective top stationary contacts CF1 , CF3 and bottom stationary contacts CF4, CF6, CF5 , each double movable contact passing through the plate P; all the movable contacts CMl, CM2 and CM3 are electrically connected, for example by strips of an electroconductive material integral with said plate P which in this case serves exclusively as an insulating support. From what above with respect to Figure 1, it is evident that a first lowering of the pushbutton PI (Figure 2B) will cause the movable contact CM3 to become disengaged from the top stationary contact CF3, thereby engaging the bottom stationary contact CF6, while the movable contact CMl will remain engaged with the top stationary contact CF1. By further lowering the pushbutton PI, the plate P will rotate around an axis passing through CMl and CM3 , to lower the opposite vertex so as to engage the movable contact CM2 with the stationary contact CF5, while the movable contact CMl will remain in engagement with the stationary contact CF1, and the movable contact CM3, that had been shifted in engagement with the stationary contact CF6, will remain in engaged condition. Likewise, a first lowering of the pushbutton P2 will cause the movable contact CMl to disengage from the stationary top contact CF1 to engage the bottom stationary contact CF4, while the movable contact CM3 will remain in engagement with the top stationary contact CF3. By further lowering the pushbutton P2, also in this case the movable contact CM2 will engage the stationary contact CF5 , while the movable contact CM3 will remain in engagement with the top stationary contact CF3, and the movable contact CMl, that had been shifted in engagement with the bottom stationary contact CF4, will remain in this engaged condition. This can be more clearly seen in Figures 3 to 8, showing the shifting steps of the movable contacts and the circuity with the apparatus to be controlled, for example relays. Figures 3 and 6 show a schematic view of the switching arrangement, in an open or inactive condition thereof, capable of controlling, for example, the two speeds of a motor, through relays: more specifically, a relay R3 , figure 4, controlling a first function, for example, the first speed of the motor, for causing an apparatus, such as a movable crane, to advance; a relay R2 , Figure 5, controlling a second function, for example the second speed of the motor, for causing the apparatus to advance or move backwards; a relay Rl , indicated with its related circuit by dashed lines in figure 3, controlling a function alternative to that of the relay R3, for example the first speed of the motor for causing said apparatus to move backwards. In Figures 6, 7 and 8, in order to simplify the illustrations, the relays have not been shown. As already stated, Figures 3 and 6 show the switching arrangement in its open condition, in which the movable contacts CMl, CM2 and CM3 are physically disconnected from the related stationary contacts CF4, CF5 and CF6, thus not feeding any of the relays Rl , R2 , R3 , since the latter are fed by the power supply clamp Ml. As a first pressure FI is applied to the pushbutton PI (Figures 4 and 7), the movable contact CM3 , Figures 4 and 7, becomes disengaged from the stationary contact CF3 and engeges the stationary contact CF6 thereby supplying power to the relay R3 , i.e. causing an electric current to flow from the clamp Ml to the stationary contact CF6 and, consequently, to the relay R3, through the conductive strips connecting the movable contacts CMl, CM2 and CM3; thus, the so energized relay R3 will provide in this case, for example, the first advancing speed of the apparatus driven by said motor. By subsequently applying to the pushbutton PI a greater force F2 (Figures 5 and 8), the movable contact CM2 will become engaged with the stationary contact CF5, thereby creating a further closed circuit, simultaneously to the one defined above, shown in Figures 4 and 7, namely the relay R2 which energizes a second winding of the electric motor to provide a second speed to — y — the apparatus driven by said motor. With reference to Figure 9, it must be pointed out thanks to this specifically designed novel construction of the switch, by simultaneously pressing the two pushbuttons PI and P2, and consequently applying two simultaneous forces FI and F3, the power supply clamp Ml will become electrically disconnected, thereby opening the circuits connected to the relays Rl , R2 and R3. Thus, this "electric locking" function will prevent two relays associated with opposite movements (Rl, R3) from being simultaneously actuated, it not being possible to perform such opposite movements, for example in the case of a motor the two rotational directions of which are controlled by two relays. What described above also holds good, in an analogous manner, when the pushbutton P2 is actuated through the force FI to energize the relay Rl so as to provide a first driving speed, in a direction opposite to that provided by the relay R3 to the apparatus controlled by said motor, or through greater force F2 to energize the relay R2 so as to provide a second driving speed to the apparatus controlled by said motor. For example, Figure 10A shows a top plan view of the same switch as that of Figure 2A which differs with regard to the operation points of the pushbuttons PI and P2; and Figure 10B shows a schematic view of the switch in its open condition. A first pressure FI applied to the pushbutton PI (Figure 10C) will cause the closure of the electric circuit of the relay R2 passing through the power supply clamps Ml and M2. A further pressure F2 applied to the pushbutton PI (Figure 10D), having varied the application point of the driving force, i.e. by causing the pushbuttons PI and P2 to move towards the spring M, will disengage the plate P from the clamp Ml, thereby deactivating the relay R2. Such a variation can find application in some safety switches, which serve to deactivate a given apparatus (in this specific case controlled by the relay R2 ) when the switch is released (as schematically shown in Figure 10B), or when an anomalous pressure is applied to the actuator (which case is schematically shown in Figure 10D). Figures 11 and 12 show an exploded view of the switch, as seen from the top and from the bottom, respectively, made according to a preferred embodiment of the invention as shown in Figures 3 through 9, in which the pentagonal plate P is made, from the constructional view point, by using two components assembled one onto the other. More specifically, the switch consists of a base 10 having an inner cavity in which is fitted a cylindric coil spring M passing through a hole 11 of an intermediate cover element 12 projecting from the latter. On the top surface of the intermediate cover 12 are mounted: two bottom stationary contacts CF4, CF6, equal to each other, connected to clamps Ml, M3; the stationary contact CF5 connected to clamp M3 ; as well as the clamp M4 into which will be inserted a terminal 29 of an element 28 forming a common top contact CF1 to CF3. Said common contact element CF1 to CF3 is housed on the bottom of the cavity of the top cap 13. A contact-bearing element 18 made of electroconductive metal having three arms 19, 20, 21 bearing, respectively, the movable contacts CMl, CM3, CM2 is provided. Said contact-bearing element 18 is supported by a plastic carrier element 16, having two arms 43 and 44 slightly radially offset with respect to the arms 19, 20, 21 of the contact-bearing element 18. Carrier 16 presents a central disc-like hub 17 integral with the two arms 43 and 44, said hub 17 supporting the spring M. Hub 17 is joined to the contact-bearing element 18 by means of a screw 45 engaged in a hole 46 of element 18. The contact-bearing element 18 and the carrier element 16 operate together acting as the plate P of the previous figures. On the ends of said arms 43 and 44 bear the bottom ends of two control pushbuttons PI and P2 having two overlapping slots 38 and 39 so that the precision sliding of the pushbuttons through the holes 40 is contrasted by said slots 38 and 39, as well as by two springs 30 urging rollers 31 inserted in suitable recesses formed in the top cap 13, which rollers 31 laterally engage the slots of the pushbuttons PI and P2 so that as the first hindering slot is engaged, the user will feel this as the reaching of a first operating position of the pushbuttons, whereas the reaching of the second hindering slot is perceived, as the reaching of the second operating position of the control pushbuttons. Above the top cap 13 a pressing plate 32 overlapped by a sealing rubber sleeve 52 is arranged. In said control pushbuttons PI and P2 are assembled springs 50 for optimizing the electric operation of the switch when the outer buttons 51 are actuated. The force FI is applied to the pushbutton PI through the spring 50 inside said pushbutton, which spring is pressed by the outer button 51. The suitable selection of the dimensions of the spring 50 allows the plate P, bearing the movable contacts CMl, CM2 and CM3 , to reach in a correct and stable manner the different operating positions of the switch, the reaching of any intermediate position being prevented. In order to complete and close the assembly of the switch, two screws 42 locking with one another the base 10, the intermediate cover 12 and the top cap 13 are used.

Claims: CLAIMS 1. An electric switching arrangement, characterized in that it comprises a plate (P) made of electroconductive material bearing at least one movable contact (C3 or C4) and being supported by a spring (M) in turn supported by a fixed base (B); at least one bottom stationary contact (Cl or C2) apt to engage said at least one movable contact (C3 or C4) , and at least a control pushbutton for applying a pressure force (F) to said plate (P) at a position variable between a point substantially aligned with said at least one movable contact (C3 or C4) and any point whatsoever between said movable contact and spring (M) , whereby at least one of said movable contacts (C3 or C4) is brought into contact with at least one of said stationary contacts (Cl or C2). (Fig. 1). 2. An electric switching arrangement according to Claim 1, characterized in that it comprises two bottom stationary contacts (Cl, C2), an electroconductive plate (P) , bearing two movable contacts (C3, C4) and being supported by a spring (M) at an intermediate position between said two movable contacts (C3, C4), and a control pushbutton for applying a driving force (F) to said plate (P) at a position variable between a point substantially aligned with one (C3) of said movable contacts and any point whatsoever between said spring (M) and said movable contact (C3), whereby said movable contact (C3), upon said pushbutton being lowered by a force (F) into a first position, is brought into contact with one of said bottom stationary contacts (Cl) and, upon a further lowering of said pushbutton, the other movable contact (C4) is simultaneously brought into contact with the second bottom stationary contact (C2), too. (Fig. 1). 3. An electric switching arrangement according to Claim 2, characterized in that it comprises at least two top stationary contacts (CF1, CF3), arranged on at least two vertices of an isosceles triangle; three intermediate movable double contacts (CMl, CM2, CM3 ) , arranged at the vertices of said isosceles triangle, supported by at least one plate (P) bearing said movable contacts, plate (P) being urged by a spring (M); three bottom stationary contacts (CF4, CF5, CF6) , arranged at the vertices of said isosceles triangle; and two control pushbuttons (PI, P2) for applying a lowering force (F) at a point substantially aligned, on a single axis, with two respective movable contacts (CMl and CM3). respectively) , each of said two control pushbuttons (PI, P2) being able to apply a pressure to said plate (P), bearing said movable contacts (CMl, CM2 , CM3), at a position between said spring (M) and one of said side movable contacts (CMl, CM3), arranged on the base of said triangle, one of said two side movable contacts (CMl or CM3), upon the lowering of either one or the other of said control pushbuttons (PI or P2) to a first position, holding at the same time a first top stationary contact (CFl or CF3) in engagement with a corresponding first movable contact (CMl or CM3) and bringing a second opposite movable contact (CM3 or CMl) in engagement with a second bottom stationary contact (CF6 or CF4) , whilst, upon a further lowering of said control pushbutton (PI or P2) to a second position, a third movable contact (CM2) is moved in engagement with a third bottom stationary contact (CF5), holding at the same time said stationary top contact (CFl) in engagement with the first movable contact (CMl) (Figs. 2A to 2C ; Figs. 3 to 8), whilst a simultaneous application of forces (FI and F3) to the two control pushbuttons (PI and P2) causes the electric circuit (Fig. 9) to be opened. 4. An electric switching arrangement according to Claim 2, characterized in that it comprises at least two top stationary contacts (CFl, CF3), arranged on at least two vertices of an isosceles triangle; three intermediate movable double contacts (CMl, CM2 , CM3), arranged at the vertices of said isosceles triangle, and supported by at least one plate (P) bearing said movable contacts, plate (P) being urged by a spring (M) ; three bottom stationary contacts (CF4, CF5, CF6) , arranged at the vertices of said isosceles triangle; and two control pushbuttons (PI, P2) for applying a first lowering force (FI) at a point between the spring (M) and a respective movable contact (CMl and CM3), each said control pushbutton (PI, P2) being able to apply a pressure to said plate (P), bearing said movable contacts (CMl, CM2, CM3), at a position between said spring (M) and one of said side movable contacts (CMl, CM3), arranged on the base of said triangle, one of said two side movable contacts (CMl or CM3), upon the lowering of either one or the other of said control pushbuttons (PI or P2) to a first position, holding at the same time a first top stationary contact (CFl or CF3) in engagement with a corresponding first movable contact (CMl or CM3) and biassing a second opposite movable contact (CMl or CM3) to become in engagement with a second bottom stationary contact (CF6 or CF4) , whereas, by a further lowering of said control pushbutton (PI or P2) due to a greater force (F2) into a second lowering position, both said movable contacts (CMl and CM3) are disengaged from the top stationary contacts (CFl and CF3) , opening at the same time the electric circuit (Figs. 10A to 10D). 5. A switch according to Claim 3, characterized in that it comprises a base (10) having an inner hollow in which is arranged a cylindric coil spring (M) passing through a hole (11) of an intermediate cover (12) and projecting therefrom, on the top surface of the intermediate cover (12) being mounted two bottom side stationary contacts (CF4, CF6) , each ending with clamps (Ml, M3); a stationary contact (CF5) connected to a related clamp (M3) ; and a clamp (M4) in which is inserted a terminal (29) of an element (28) forming a top common contact (CFl - CF3), said common contact element (CFl - CF3) being housed on the bottom of the cavity of a top cap (13); a contact-bearing element (18), made of electroconductive metal having three arms (19, 20, 21) and bearing the respective movable contacts (CMl, CM3, CM2), being provided, said contact-bearing element (18) being supported by a plastic carrier element (16) having two arms (43 and 44) slightly radially offset with respect to the arms (19, 20 and 21) of the contact-bearing element (18); said carrier element (16) having a central disc-like hub (17) integral with the arms (43 and 44) and supporting the spring (M) and operating as a joining element through a screw (45) engaged in a hole (46) of the contact-bearing element (18), said screw (45) engaging itself in the disc-like hub (17) of the carrier element (16), the ends of said two arms (43 and 44) supporting the bottom ends of two control pushbuttons (PI and P2) having two overlapping slots (38, 39), the precision sliding of said pushbuttons through the holes (40) being contrasted by the slots (38, 39) and by two springs (30) urging suitable rollers (31), inserted in suitable recesses formed in the top cap (13), which rollers laterally engage the slots (38, 39)of the pushbuttons (PI, P2) for contrasting a displacement of said control pushbutton so that, as a first hindering slot is engaged, a user will feel this as the reaching of a first operating position of the pushbuttons, whereas the reaching of the second hindering slot is perceived as the reaching of the second operating position of the control pushbuttons, a press plaque (32) overlapped by a sealing rubber sleeve (52) being arranged above the top cap (13), the assembly being closed by two screws (42) locking with one another said base (10), the intermediate cover (12) and the top cap (13).

Inventors: DIELEMAN JAN PIETER, DIELEMAN, JAN, PIETER
Applicants: DIELEMAN JAN PIETER, LUXDER LLC, DIELEMAN, JAN, PIETER
Application year: 1999
Main classification: H01H13
IPC codes: H01H13