GB2266165A - A control arrangement for an electrical windscreen wiper motor - Google Patents

Description

2266165 A control arrangement for an electrical windscreen wiper motor The

invention relates to a control arrangement for an electrical windscreen wiper motor which can be directly switched on via contacts of a control switch. Such a control arrangement is shown, for example, in DT 24 07 812 C3.

Dispensing with relatively expensive relays for switching the motor current, the different wiping speed steps are directly switched on by this means via the sitching contacts of the windscreen wiper control switch, wi 1 1 which can be manually switched to different steps, which contacts are designed for switching the load current of the motor.

In the known control arrangement, the control switch has two synchronouslymovable switching contacts, the first of which forms the actual step switch in interaction with its stationary contacts but the second of which forms a bridge between a switching contact of a relay, only used for interval cycling and one of the connections of the motor in the off-position and in the interval position of the control sitch.

wi The parked position switch for the motor which can be mechanically directly switched by it is connected in th the change-over contact of the interval relay series wi when the latter assumes its rest position, and with the second switching contact of the control switch.

This arrangement has the advantage that the motor is rapidly stopped by connection to earth potential on both sides after the control switch is switched off or respectively after an interval wiping cycle has concluded.

A certain disadvantage of such a control arrangement is, however, the length of the electrical lines which must be run from the parked position switch first to the interval relay, from this to the control switch at the steering column of the vehicle and from there back to the motor.

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A control arrangement- for velhicle windscreen wipers is known ( IDE 2.1 03 311 AU), 4-1le conit--rol switch of which, exhibiting two swi-Lcil-lirg cont,-act.--s, does noll: have its own ises a _Lnterval switch pos-LL--lon bJut w'L-14Lc'L-L all same compri cycle swl"t--ch for sult-J3jectively derLtanL--'j-depenu,'en't--ly setting the -,lura.'-'on of t1Cle intt--erval pause.

e s w c h - o n p o s o n a 11 o c a IL a d t o slow continuous operation of t_lne control switch is also used for the interval operation. For periodically sw't- 1 -L L- -L ch ' ng tihe rta4L-or on and stopping it in intervalL operation, t_1he line Stationary con-t-ac-"L of -L'--he control switch allocated to tihe SLOW Con4tinuous operation and ^L--."LLe corresponding ruo tor connection is run via a Contact of a relay Controllable by tihe said cycle switch and switched "L-..II-Lrougil-L in t-1-Le rest posl-t"-ion of this relay whilst the sanue relay interrupts the a-ILorer,,en41-,loneLAJ line in its operating position CLIKA C01 11 le CIL's the cillange-over contact of the parikel-111 position switch U_Lrectly to -IE-hLe said mot-or connection via a bypass current pa This bypass current path functionally necessary for executing thle interval operation because of c).p 4 ha relay deviating from the prior art exclusively

J_ L-11 1 k_ L.

used for tAL-le Current supply to rLto-L--or, controllable by parked position switch, in interval rode during IL-he conclusion of a wiping cycle before the beg"L.-Li-iL-Lng of an -Ln,'t--erval pause in which the change-aver contact of the relay assurues operating position. In contrast, it is currentless both in continuous rode of the ruotor and in the swi.lt--c'L-LeA"-o-JO-J'7 position oif -1-21-Le control switch. In no=mal operation, it can therefore only conditionally contribu't.-.e to relieving of 4&--J'^Le contacts of the control switch and not slt^lortening of the current pat-hs.

FurtIt-Ler details anCI ak--Alvan-IL- ages are.10ounL--I& in "L-il-ie 1-'us'-rave erLbodrLen"- and its more dletailed drawing o-l a n 1 C! -L t_ "A J-3 description following 'L-lerew,;LL-11, W-1.L.11 re-Earence -It--o 'ICI-Le drawing, in whlci"i.:1-ows scheritat cally a c rcuit d' agram of a igure 1 sh control arrangement- a bypass curren"t'-- path 'for rel'-"-the contact-s o:E the manually switchaili-le control switch, Figure 21 sIL-Lows an erLLII-Jodirtien'L-- of- JL.-.'.L-Le bypass current path with a lt:ransistor as swill-ching eler,,en4--, and Figure J shows a constructiona-1 -JO-orr,, of t'lle parked posiCion switch supp'LerLenj---e".-3 by an au-."d"onal contact for connecting ICII-le: bypass current pat"-11-1. control switch 4, wI-L!c IL- 1 can be manually switched can be connected in seQ=j-cz.-L steps, wit-1h a sl1Q111CJ k-UJIUCX C Ii &-WU via a fuse and an operating Swii,_-CII-L Z0a t_o tihe posit-live le, not termina]. of an on-boarx-A' volt-age source 'L of a veh-Lc-L sil-Lown in greater detail in Figure 1, comprising at least- one windscreen wiper 2 and a revolving windscreen wiper -iLLotor hereinafter jjrie.Loly called motor - 3 driving this wipervia a transmission, not. sil-Lown. Al first switching contact 1.1 of tihe control switc1h, e-'Lec"L-rl'ca-LI'Ly continuously connected to J-3- s-I A Z= 1 1 to 4-s _i..Le IldLng crirltl--clk-x- _if -L;=, CL-L-I-Uk-CLA._ tAI in a-"-3"torL L_ 1 L_ 44- -e-2-o'2-0 posItIon deslgra4-e-" by 11011, a first stationary SW-Lt-c.1L.L -L 1.1--- E! L- L- L. -L -errIL.I- t_ &--L tA contact- IvIll for _Lnterval or int LL'tten-l- operation, a second 14- - _ st-ationary cor L-cLk-t- triltt for slow continuous operation and a ICAL-LirLd stationary cont-act- 2sty LEu^j- ICIL-le C as con4- J_;__Lnuous operation o-LE the rLo-IL--or 3.

TIL-Le J0- Irst'-- stationary contact "I" is conriect'--e-,QX tothe input of an initerval control device, here only diagram- r,La"t--ically represented as t-lruing section, or t_ime function r_lay (time function re-lay', 6, tihe opera-'&--ing mokale and e L I- J_ CI -L fur'k--.'L-Ler electrical wiring (volt-age supp.'Lly) of which is assu-med 4Co be J11-Lnown in this case.

The second stationary contact "W is directly connected via a fuse to a -&'--eri-ti-Lnal 3L oIO the motor 3 wil-lich is permanently connect-ed to earth potential at It-2he other end.

M" L, k_1lird' stationary contact "S" is also connected via a fuse directly to a terminal 3S of the rLLo'k---or 3. The two fuses can also be in view of -IL"I-Je fuse preceding 41 Li provided in any case.

second switching contact 4.21 of tChe control switch 4 can be moved in synchronism wit-1-1 til---le first switching contact 4.1. This second switching contact forms a bridge two sliding contacts 7 and 8 in thle and in the interval position of 4L--.'L-Le control switch whilst the sliding contacts are electrically isolated from one another in the continuous operating positions of tihe control switch A 11 - 4 and are only connected again after the disconnect-Lon of continuous operation at t_he control switch. This is 4- - "a pos,-" indicated by a dashed reproduction of L-11 itlon of the control switch 4 'in which -its first switching contact 4.1 connects sliding contact cj t_o stationary contact.

E ike the stationary cont-act 11Lrl, the si"-1'd,'L-ng contact L. L_ L- J1 of control switch 4 is perrLaneri-tl---'Ly connected to t_11-Le -17' of' "e motor via --a -1'use.

terminal -31, J_ E3.1.

An essential component. of the time function relay 6 is a relay 91, which can be cyclically operated for interval operation, a cil-lange-over contact 10. The latter is permanently connected to tha sliding contact '17 of 4C1-Le control switch 4 and in its rest position is connected to a nor-mally-closed contact 10.1 from which it can be switched 4- tt-o a norma 1 ly- open contact 10.2, wjl.-ilcil-L can be connected Co positive potential via t. 11-1 a operating switch Z'JU, J.JY activating t4-.'L-Le relay 9.

The -motor 3 is allocated in fa-miliar manner a parked posittion switch 11 having a change-over contact 12 which is perr,,anen'['--ly connected to tihe nor-mally-closed contact 10.1 of LI.Le relay 9. In its rest position, the change-over contact 12 rests against a normally-closed contact- 121.1 permanently connected to earth potential fro-m which!"L: can be switched -LrLtmedia,L'--ely after each starting of 4C1-Le ruotor frorn its rest position to a normally-open contact 12.1 which can also be --^----ing switch -0 connected to Pot-eL E-LELL via "L-11- it- J.1 2JU.

In this known manner, a cyclic seli'--1t"lol,-,--ú,Iing of the mo tor y current is achieved each w-Lping cycle is complete-L -04, _ i hed.

I-InIsil L. 12. -L L, EU L.

W.L.Len the parll-Led' position sw"-ch J1 then ret rns to its rest. pos-LL-lon shown, the motor 3-5 Is si-lor-;_c4Lrcui-A-e-4 3io th ends to earth) via the chLlange-over contact 10, which is in it- hing contact.

its zest pos-";L4L--ion, of the relay 9 and the swt"-c.L.LI L- L A. n -' 'I- I- e s 14 -11 -acts 7 and 8 of the control sw!4t--cl- I- anu L.11 -LU.Lng conlt.- 1_. J_ L_ L.L Up t_ ill 1 now, Cne representation functionalLy - -.I.. ' - 4- 4 - 1 -1 ' ' corresponds to th=e 1JJ-101. CLIL- 1.ti-LI--LCL-L-L.Y ment-loned. Compared W-4Ltt-."L1. that, a bypass current path 13 has been added between the change-over contact 12 and the terminal 3L of the mott-or 3, which comprises one or a number of diodes 14. The diodes 14 are connected in such a manner that a current f low is only possible from the change- over contact 12 towards the motor 3. Current can thus only f low through the bypass when the diodes are intact - in dependence on the position of the parked position switch 11, namely, only when its change-over contact 12 has been switched from the running motor 3 to the normallyopen contact 12.2. Otherwise it is stched off.

wi W7hen the ignition switch M is closed, the following sequence/current flow is obtained on switch-on or brief moving past the interval position of the control switch 4 (switch contact 4.1 on stationary contact "I"):

The relay 9 is immediately activated for approximately 0.5 sec via time function relay 6 so that positive potential (from ZU) can pass via its change-over contact 10 switched to the normally-open contact 10.2, the sliding contact 7, the switching contact 4.2 and the sliding contact 8 to terminal 31. of the motor 3. Immediately (approximately 0.1 sec) after the starting of the motor which now follows, in any case during the switched-on period of the relay 9, the change-over contact 12 of the parked position switch 11 is switched from the normally-closed contact 12. 1 to the 7 normally-open contact 12.2 so that it now also carries positive potential.

If then the change-over contact 10 of the relay 9 drops back to the normally-open contact 10.1 after the period predetermined by time function relay 6 has elapsed, the change-over contact 12 of the parked position switch 11 handles the full motor current. However, this only partially flows as previously via the current path ZU - 12.2 - 12 10.1 - 10 - 7 4.2 - 8 - 3L and the bypass current path 13 with its diodes 14 (current path ZU - 12.2 - 13 14 - 3L) then handles another part of the motor current.

The latter diodes are only necessary for preventing short circuits for the short period between the switchingover of relay 9 and the switching- over of the change-over contact 12 of the parked position switch 11.

Naturally, a switching element, for example an NPN transistor 141 or FET, can also be provided as current valve instead of the diodes 14 as shown in the detail according to Figure 2, in the bypass current path 13, which transistor only switches to conduct the bypass when the parked position switch 11 is switched into its operating position. The collector-emitter path of the transistor 141 is connected between the operating switch M1 and terminal 3L of the motor 3, is thus directly provided with positive potential whilst the base of the transistor 141 is connected via a resistor 15 to the change-over contact 12 of the parked position switch 11. In addition, a high-resistance resistor 16, which is only indicated in dashes. can be connected in parallel with the base-emitter path and the motor 3. This circuit can also be used to achieve a certain relieving of the parked position switch 11 since it now only needs to carry a low (base) component of the bypass current.

The same divided current flow occurs also in continuous wiping mode when the parked position switch is switched over. AS previously in interval mode, some of the motor current from the parked position switch 11 now flows via the bypass current path 13. Since the latter is much shorter in comparison with the previous current path via the control switch 4 and only has a small voltage drop, a significant relieving of the control switch 4 can be J_ measured. Similarly, the influence of the voltage drop across the long connection to the motor 3 run via the control switch is reduced and the cable cross-section of this connection can now be reduced.

A further advantage of this arrangement is that when the fast continuous mode (switching contact 4.1 to stationary contact 'IS", terminal 3S of the motor to positive) is switched on, the terminal 3L is also torqueincreasingly supplied with current via the bypass current path 13.

1 the Although lt would be conceivable to omi connection between the parked position switch 11 and the normally-open contact 10.1, this would lead to a deterioration in the above-mentioned braking effect of the circuit.

In the variants of the control arrangement hitherto described. no modification was made on the usual parked position switch. In the embodiment according to Figure 3, however, the latter is supplemented by an additional normally-open contact 12.3 which is brought into electrical connection with the change-over contact 12 together with the normallyopen contact 12.2 during the switching-over. The bypass current path 13 now extends directly - and without comprising other components - between the additional normally-open contact 12.3 and the motor terminal 3L whilst the stationary connection provided in the two embodi-iments described above of the bypass current path 13 to the switching contact 12 is omitted.

The function otherwise remaining the same as the two shown in Figures 1 and 2, this variant has the advantage that the bypass current path can again only carry a current when the parked position switch 11 is switched to its operating position but that, at the same time, it is not necessary to provide current valves or semiconductor components. A simple short line connection without 9 significant voltage drop is sufficient since, as a rule, no "reverse current" can flow from motor terminal 3L to the parked position switch 11.

compared with circuits with motor current relays, the arrangements described here have the advantage that the entire short bypass current path can be accommodated in the immediate vicinity of the motor 3, even inside its housing, which is not possible with relays. In addition, the bypass current path is much more insensitive to the environmental conditions prevailing in the installation space of the motor.

It should be noted that the bypass current path 13 could also be appropriately arranged with the aforementioned advantages in the abovementioned known control arrangement interval switch position of the control switch in wi 1 1 1 parallel with the bypass controlled by the interval relay.

claims 1 A control arrangement f or an electrical windscreen wiper motor which can be directly switched on via contacts of a control switch, comprising - a parked position switch with a change-over contact for supplying a terminal of the windscreen wiper motor with power after the starting from a parked position and for stopping it after completion of a wiping cycle after the continuous operation of the windscreen wiper motor has been switched off at the control switch, itching contact of the control switch, electrically a swi connected in series with the change-over contact of the parked position swit-ch, passing current to the terminal of the windscreen wiper motor via an associated stationary contact, at least after the switching- off of the continuous operation during a current wiping cycle, wherein a bypass current path is connected in parallel with the control switch, independently of its position, for directly supplying the terminal of the windscreen wiper motor with power in the operating position of the parked position switch.

Claims (1)

1. 2. A control arrangement according to Claim 1, wherein at least one

   component is located in the bypass current path a nd through which current can flow from a voltage source to the terminal of the windscreen wiper -motor in dependence on the position of the change-over contact of the parked position switch.

   3. A control arrangement according to Claim 2, wherein the at least one component is a diode.

   4. A control arrangement according to Claim 2, wherein the at least one component is a transistor, the base or gate electrode of which is connected to the change-over contact.

   5. A control arrangement according to Claim 1, wherein the parked position switch comprises a normally-open contact which is provided for connecting the bypass current path and which, in the operating position of the associated changeover contact, is at the same time brought into electrical connection with a first normally-open contact, used for supplying the windscreen wiper motor with power, of the parked position switch and with the change-over contact.

   6. A control arrangement according to Claim 2 or 5, wherein the windscreen wiper motor can be switched on in a slow and in a fast continuous wiping mode via a first switching contact of the control switch and associated stationary contacts, the terminal of the windscreen wiper motor for the slow continuous wiping mode also being supplied with current via the bypass current path when the fast continuous wiping mode is switched on.

   7. A control arrangement according to Claim 1, 2 or 5, wherein the bypass current path extends close to the motor. 8. A control arrangement according to Claim 7, wherein the bypass current path, together with the parked position switch, is accommodated at or in a housing of the windscreen wiper motor.

   9. A control arrangement for an electrical windscreen wiper motor which can be directly switched on via contacts of a control switch, substantially as described herein with reference to and as illustrated in the accompanying drawings.