US3247335A

US3247335A - Arrangement for programme selector switches in electric washing machines

Info

Publication number: US3247335A
Application number: US288215A
Authority: US
Inventors: Holzer Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-06-23
Filing date: 1963-06-17
Publication date: 1966-04-19
Anticipated expiration: 1983-04-19
Also published as: DE1413846A1; DE1413845A1; DE1413845B2; GB1045166A; FR1366249A; DE1413846B2

Description

Apnl 19, 1966 w. HOLZER 3,

ARRANGEMENT FOR PROGRAMME SELECTOR SWITCHES IN ELECTRIC WASHING MACHINES Filed June 17, 1963 5 Sheets-Sheet 1 .iLQL

//v VEN TOR! WALTER 170L252 Atforney5 April 1966 w. HOLZER 3,247,335

ARRANGEMENT FOR PROGRAMME SELECTOR SWITCHES IN ELECTRIC WASHING MACHINES Filed June 17, 1963 5 Sheets-Sheet 2 FIG.4.

Ii] 1 lllllllllllllHl-58 IH'F 9:111}; A 263%? 1] a0 INVENTOR:

WA LTER HOLZER Attorneys Apnl 19, 1966 w. HOLZER 3, 47

ARRANGEMENT FOR PROGRAMME SELECTOR SWITCHES IN ELECTRIC WASHING MACHINES Filed June 17, 1963 5 Sheets-Sheet 5 IN VENTOR WALTER HOLZER BWQW A Horney;

Apnl 19, 1966 w. HOLZER 3,247,335

ARRANGEMENT FOR PROGRAMME SELECTOR SWITCHES IN ELECTRIC WASHING MACHINES Filed June 17, 1963 5 Sheets-Sheet 4 IN VE N TOR WALTER HOLZER A tforney5 April 19, 1966 w. HOLZER 3,247,335

ARRANGEMENT FOR PROGRAMME SELECTOR SWITCHES IN ELECTRIC WASHING MACHINES Filed June 17, 1963 5 Sheets-Sheet 5 INVENTOR. WALTER f/OLZER Attorneys United States Patent 3,247,335 ARRANGEMENT FOR PROGRAMME ELECTOR SWITCHES IN ELECTRIC WASIHNG MACHINES Walter Holzer, Drosteweg 19, Meershurg (Bodensee), Germany Filed June 17, 1963, Ser. No. 288,215 Claims priority, application Germany, June 23, 1962, H 46,159, H 46,160 14 Claims. (Cl. 20038) The present invention relates to programme selector switches in electric washing machines, and particularly to programme selector switches by means of which individual portions of the possible washing programme can be cut out or, as is said in the art, passed over rapidly by preselection, according to the type of material to be washed.

During these so-called passing over steps, the programme switch of necessity operates the contact of the parts of the programme to be cut out, even if only momentarily, and the various members of the washing machine connected thereto, such as the inlet and outlet valve, the heating, etc., will respond due to the momentary closing of their associated circuits. The invention aims to provide an improved programme selector switch, where the connected members of the washing machine are prevented from responding by cheap, simple means; it is particularly important that the operation of the selector switch should be reliable and insensitve to shaking, that the limits imposed on manufacturing accuracy should not be too narrow, and that adjustment of the switch should therefore be simple and time saving.

Accordingly, in programme selector switches for electric washing machines, having an intermediate switching mechanism to operate programme contacts, which mechanism is controlled by a time mechanism according to the desired duration of the preselected part of the washing programme and which operates a blocking means when the switching steps succeed each other immediately, as when omitted parts of the programme are passed over by preselection, a feature of the invention is that a blocking contact is mounted in series with a programme contact, is opened by the blocking means and kept open by a suitable latching device, and that a suitable unlatching device is provided to release the latch at the beginning of a new part of the programme.

A particular feature of the present invention is that the blocking means has a blocking pawl which is mounted for rotation and is under spring tension, and a switching pawl articulated thereto, and that a spring presses the switching pawl against a sliding track on which a vertical latching pin is mounted.

Another feature of the present invention is that a stop is provided on a rotary component of the time mechanism, and the blocking pawl is drawn into the rotary path of the stop by the spring tension.

It is therefore an important feature of the invention that a stop is provided on a rotary component of the intermittent switching mechanism, the rotary path of the stop being intersected by a projection on the blocking pawl when omitted parts of the programme are passed over.

In this connection, it is an important feature of the invention that the components of the time and of the intermittent switching mechanisms which rotate and which carry stops are in the form of circular discs.

It is therefore desirable for one of the two rotary discs having these stops to be equipped with a hollow shaft, which is mounted for rotation on the shaft of the other rotary circular disc in such a way that it is spaced from the latter disc.

It is important for the stop to be mounted on the surfaces of the circular discs facing one another.

Another feature of the invention follows from this arrangement, namely that the blocking pawl projects into the gap between the two circular discs and rocks on a plane parallel with the planes of the two circular discs.

In this connection, it is important for the blocking pawl to be biased by a spring mounted substantially tangentially to the rotary paths of the components of the time and intermittent switching mechanism.

In a preferred embodiment the unlatching means comprises an angle lever mounted for pivoting in the centre, one free end of the lever bearing perpendicularly and under spring pressure on the free end of the movable armature shaft of the common drive motor for the time and intermittent switching mechanism.

Another modified embodiment of the programme switch according to the invention is characterised in that the blocking means comprises a fiat switching pawl which is mounted for sliding along a guide track and to which a blocking pawl and an operating lever for the blocking contact are rigidly attached.

In this connection it is important for the flat switching pawl to have a narrow, straight portion, adjoining a segmental, almost rectangularly curved arcuate portion of substantially the same width, having a straight prolongation which is bent downwardly at right angles and designed as a blocking pawl of known conformation.

Further according to the invention, a slot is provided near the end of the straight part of the switching pawl, into which slot a guide pin mounted vertically on the guide track projects.

Another feature of the invention is that the edge of the straight portion of the switching pawl away from the direction of curvature of the arcuate portion is extended in a straight line at the beginning of the curve in the arcuate portion and forms a sliding projection spaced from the outer arcuate edge of the arcuate portion, a second guide pin which is also mounted on the guide track projecting into the space.

In this connection, it is important that the lever for operating the blocking contact should be an elongated narrow stamped metal member which, when arranged upright on the plane of the switching pawl at an oblique angle to the centre line of the straight portion of the latter, projects laterally beyond the switching pawl.

In order that the switching pawl can be latched against the pull of the spring when the blocking contact is open, a latching means is provided, comprising a substantially T-shaped leaf spring, of which the web and the longer lefthand side of the beam are fastened at the end to the switching pawl, while the shorter, right-hand side of the beam is at an acute angle to the centre line of the beam and at right angles to the plane of the leaf spring, and which extends through a slit in the switching pawl into a recess in the guide track below the switching pawl.

In order that the latching means can be actuated by the unlatching means, it is essential for the cross beam of the T-shaped leaf spring to have a lateral projection opposite the web, the projection being located above a known unlatching means when the switching pawl is engaged.

It is obvious that the production of the switching pawl with all its constructional details in one operation not only brings a great reduction in production costs, but also guarantees accurate relative positioning of the individual members from the outset and dispenses with any time consuming and, therefore, expensive adjustment work.

Other features and advantages will be found in the following description of the accompanying drawings, which show preferred embodiments and structural details of programme selector switches in accordance with the invention. In all the figures like parts have like references. In the drawings:

FIG. 1 shows diagrammatically the printed circuit of a programme selector switch, its programme switching discs, the drive thereof and the programme contacts operated thereby.

FIG. 2. is a view from above, partly in section, of the programme selector switch in FIG. 1.

FIG. 3 shows diagrammatically a possible embodiment of an overriding clutch.

FIG. 4 shows an embodiment of a programme selector switch according to the invention.

FIG. 5 shows the position of the programme selector switch in FIG. 4 immediately before the beginning of a new part of the programme.

FIG. 6 shows the programme selector switch of FIG. 4 immediately after the beginning of a new part of the programme.

FIG. 7 shows the programme selector switch of FIG. 4 during a passing over step.

FIG. 8 is a side view of the programme selector switch in FIG. 4.

FIG. 9 shows a modified embodiment of a switching pawl in the form of a stamped member, and its arrangement in the programme selector switch shown in FIG. 4.

FIGS. 10 and 11 show the switching pawl of FIG. 9 in various switching positions.

FIG. 12 is an end view of the item shown in FIG. 11.

FIG. 13 shows the latching means for the switching pawl illustrated in FIG. 9.

FIG. 14 is a side elevation of the latching means in FIG. 13.

FIGS. 15 and 16 illustrate the manufacture of the switching pawl shown in FIG. 9 in successive stages.

In FIG. 1, 1 refers to the first switching track, which is concentrically closed. The connecting lug 2 for this switching track, like the first switching track 1 itself, is in the form of a printed connection. Then follows the second switching track 3, with an interruption 4. This interruption is given the form of a lowered portion, in order to avoid burning off at the end of the track 3. The track 3 is also in the form of a printed connection. The first and

second tracks

1 and 3 are bridged by a wiper 5, which is mounted on a disc 6 (FIG. 2). Instead of the disc 6, the wiper 5 could also be attached to a rotary arm. The disc 6 is fixed to the rotary shaft 7. The third switching track 8 comprises the

segment

29, 9, 10, 11, and is connected to the second track 3 by the wiper 12. The wiper itself is fixed on a disc 13, which is driven by the toothed wheel 14 by means of a hollow shaft 32 surrounding the rotary shaft 7. The hollow shaft 32 is fixed to the disc 13 and to the toothed wheel 47. With regard to the supply of electricity, mains terminals 15, 16 for the motor 17 driving the intermittent switching mechanism are shown. The programme switching disc is illustrated diagrammatically by its contacts 13 to 24.

The switch operates as follows: In the position shown the wiper 5 connects the first switching track 1 to the sec ond switching track 3. The drive motor 17 thereby receives voltage from the main terminal 15 through the second track 3, the wiper 5, the first track 1, the connecting lugs 2 and the mains terminal 16. The drive motor 17 simultaneously drives the rotary shaft 7 and the programme switching disc, with the selector contacts 1 8 to 24 and the programme switching contacts. The programme selector contacts are shown diagrammatically one above the other; normally they are operated by a cam plate by means of switching cams. The spacing between the switching steps of the cam plate is determined by the programme selector contact operated. For example, operation of the programme selector contact 211 would produce the shortest spacing between the switching steps of the disc, and operation of the contact 18 the longest space. In the intervals between the switching steps the programme contacts (not shown) are operated, these being responsible for the carrying out of the washing pro- 4 gramme, for example for actuating the inlet valve, the washing or'centrifuging process, the heating, etc.

When the drive motor 17 is running, the wiper 5 is moved in the direction of the arrow 28 simultaneously with the rotation of the programme switching disc 33. When it impinges on the wiper 12, the latter carries along the disc 6 through the steep side of the incision 41 by means of the overriding part 26 or of a suitable enframement member 40 (FIG. 3). The disc 6 is coupled to the disc 13 for movement in the direction of the arrow 28. When the wiper 5 reaches the position 25 shown in broken lines, the drive motor 17 is de-energised since the wiper 12 breaks its circuit. The shaft 7 stops and the switching step has also been carried out, since the programme switch ing disc is also stationary.

The wiper 12 is moved at a uniform speed by a corn tinuously running drive motor 30, through gear wheels 56, 14-, 47, a slip coupling 31 and the hollow shaft 32. The distance covered by the wiper is accordingly a meas ure of time. The arrangement comprising the drive motor 30, the appropriate reduction and the wiper 12 is termed a time mechanism. The intermittent switching mechanism is formed by the drive motor 17, the wiper 5 and the appropriate reductions, for example with

toothed wheel

51, 46 and clutches. The position 27, shown in broken lines as the starting position of the wiper 12, is the starting position. The time taken by the wiper 12 to move from this temporary position 27 until it impinges on the

segments

29, 9, 10, 11 results in spacings of different lengths between the switching steps of the disc 33. The

segments

9, 10, 11, 29 are connected to the

selector contacts

18, 19, 20, 2-1 by the connecting lug 5 2, 53, 54, 55. Depending on which of the

contacts

18, 19, 20, 21 is closed, the potential reaches the corresponding segment of the third track. The time taken by the wiper 12 to reach the energised segment 10 from the broken line position 27 is the interval of time at which the programme switching steps succeed one another. In FIG. 1, the selector contact 19, which is located on the programme switching disc in this example, is closed, but may also be opened; for example it may be operated by a switch measuring a physical size. When the slide 12 reaches the position shown in FIG. 1, the drive motor 17 receives voltage from the main terminal 1 5 through the second switching track 3, the wiper 12, the segment 10, the contacts 19 through the drive motor 1'7 to the main terminal 16. Thus the slide '12 starts the drive motor 17 and the latter moves the slide 5 of the intermittent switching mechanism, which is mechanically connected to the disc 6, in the direction of the arrow 28. The position of the wiper 5 shown in full lines in FIG. 1 is that the momentary state where the wiper 12 of the time mechanism has started the drive motor 17 of the intermittent switching mechanism and the latter then connects itself to voltage through the wiper 5, i.e. where the starting circuit through the wiper 1-2 is no longer necessary. The process described above then takes place, that is to say, the wiper 5 entrains the wiper 12 and the cycle begins afresh. A slide coupling 31 enables the slide 12 to be entrained in known manner against the entrainment force of the drive motor 31}, which would move the wiper 1 2 more slowly.

Instead of the four

segments

29, 9 to 11 shown, any number of segments may be provided, as may any number of selector contacts 18 to 2 4. The drive reductions from the

drive motor

17 and 30 to the rotary shaft 7 and toothed wheel 14, respectively, may be chosen at will. The two drives 17 and 30 may also be combined, for example with one mot-or, which is given two switching positions by means of a slide armature. The overriding clutch may also be designed differently.

In the example the conductive contact tracks are arranged on a base 50 in the form of a printed circuit.

In FIG. 4 the disc 57 0f the intermittent switching mechanism is drawn over the shaft 7, on which a hollow shaft 32 carrying a disc 58 of the time mechanism is mounted for rotation. The shaft 7 and hollow shaft 32 are driven from below by a known time and intermittent switching mechanism.

Stops

59, 60 are suitably attached to the

discs

57, 58 or are pressed out of the material of the disc and bent at right angles as shown in the drawing. The blocking pawl 61 is wound perpendicularly on to a shaft 62 having a flattened end 63, on to which the spiral compression spring 64 is fitted. The flattened end 63 of the shaft 62 is mounted in a hole in the plate or housing wall 65 of the gearing for the time and intermittent switching mechanism, while the other end of the shaft 62 is equipped with a pin 66 also mounted for rotation in a hole in the plate or housing wall 65. A switching pawl 68 made of a comparatively thin metal strip is provided near one end with a slot 69, enabling this end of the pawl 68 to be fitted on to the flattened end 63 of the shaft 62 and pressed against the housing wall 65 by the spiral compression spring 64. The pawl-63 is curved twice in opposite directions near the slot 69 and is led through a slit 76 in the housing wall 65; it then extends outside the housing wall 65 towards a rest contact switch, which in the present application is defined as a blocking contact 71.

Shortly before the blocking contact 71 the switching pawl 68 is bent obliquely to its longitudinal axi at an angle of approximately 45 and forms a cam surface 72 at right angles to the plane of the switching pawl. As can'be seen from the drawing, the blocking pawl 61 extends between the two

discs

57, 58 and is pulled by a spring 73 in the direction of the arrow A. The blocking pawl 61 can follow the pull of the spring only until the switching pawl 68, which is coupled to it, bears on the limit pin 74.

In spite of the pressure of the spiral compression spring 64, when the switching pawl 68 is in the position shown, it bears neither on the inside nor the outside of the housing wall 65. Mounted on the housing wall 65 below the blocking pawl 68 near the cam surface 72 is a latch pin 76, which protrudes at right angles from the wall 65 and projects beyond it substantially by the width of the material of the pawl 68. As will be explained hereinafter, the latch pin 76 is used to lock the pawl 68 against the pull of the spring 73 when the blocking contact 71 has been opened by the cam surface 72.

FIG. 5 shows the relative position of the

stops

59, 60 before the beginning of a new part of the programme. In this position the end of the blocking pawl 61 is made to bear on the stop 60 of the disc 53 of the time mechanism by the pull of the spring 73. As mentioned above, the switching pawl 63 does not bear on the outer surface of the housing wall 65 but, in spite of the pressure of the spiral compression spring 64, is held up in a slightly angled position by the latch pin 76.

' FIG. 6 shows the relative position of the stops 59, 65) immediately after the beginning of a new part of the programme. In accordance with the constructional features of known programme selector switches where the intermittent switching mechanism is controlled by a time mechanism, at the beginning of a new programme the time mechanism and thus the stop 60 on the disc 58 first move in the direction of the arrow B, and the circuit for driving the intermittent switching mechanism is closed only after a certain preselected length of time. The stop 59 of the disc 57 consequently remains in the position shown. The movement of the disc 5% causes the front end of the blocking pawl 61 to slide off the stop 60 and to be drawn towards the centre of rotation of the

discs

57, 58 by the spring 73. The projection 75 is therefore outside the rotary path of the stop 59 on the disc 57, so that at the end of this part of the programme the disc 57, without contacting the stop '75 on the pawl 61, can complete a revolution during which the intermittent switching mechanism operates the programme contact for the next part of the programme. As a result of the movement of the blocking pawl 61, the switching pawl 61 has also been entrained in the direction of the arrow C as far as the stop 74, but still bears in a slightly inclined position on the end of the latch pin 76.

FIG. 7 shows the relative positions of the

stops

59, 60 on the

discs

57, 58 during a passing over step. In accordance with the constructional features of known programme selector switches, the intermittent switching mechanism entrains the time mechanism at the same rotary speed during the revolution in the passing over steps, by means of the overriding clutch 26, so that the two stops 59, 60 on the

discs

57, 58 rotate without altering their relative angular position as shown in FIG. 7. During these revolutions, the stop 5? follows the stop 60 at such a short interval that, instead of the blocking pawl 61 sliding off behind the stop 60 and being drawn towards the centre of rotation of the

discs

57, 58, the stop 59 engages the projection 75 and pushes it out of its rotary path in the direction of the arrow D. This movement also causes the pawl 68 to be moved in the direction of the arrow D. The cam surface 72 presses the actuating pin 77 into the blocking contact 71 and opens it. At the end of this movement the front edge of the switching pawl 68 arrives behind the latch pin 76, is applied flatly to the outside of the housing wall 65 behind the latch pin 76 by the pressure of the spiral compression spring 64 and remains in this locked position. This operation causes the blocking contact 71 to be opened and held open by the cam track 72. In this position a lateral projection 78 on the pawl 68 is located above an opening 79 in the housing wall 65, through which, as will be explained hereinafter, the cam shaped end of an angle lever 80 projects.

FIG. 8 shows a possible embodiment of a programme selector switch where a common drive motor 17 with a slide armature is provided for the time and the intermittent switching mechanism. One free end of an angle lever 89, having a bearing 81, is pressed in the direction of the arrow E against the free end of the rotor shaft of the drive motor 17 by a tension spring 82. The other end of the angle lever 80 is curved in a cam shape and, as already explained in connection with FIG. 7, extends through an opening 79 in the wall 65. If the switching pawl 63 is in the locked position, as is the case during the passing over step, the lateral projection 78 is immediately above the cam shaped end of the angle lever 80. At the end of the passing over steps, suitable cams on programme selector switches break the circuit for driving the intermittent switching mechanism in known manner and close the circuit for driving the time mechanism. In the example shown in FIG. 8, the closing of the circuit for driving the time mechanism results in displacement of the armature of the drive motor 17 in the direction of the arrow B. Accordingly, the free end of the rotor shaft also moves in the direction of the arrow B and the angle lever 86 can be turned anticlockwise by the action of the spring 82. During this movement the cam shaped end of the angle lever 82 engages the lateral projection 78 on the pawl 68 from below and raises it above the latch pin 76. The pawl 63 thus released can now follow the pull of the spring '73 and move into the position shown in FIG. 6. During this movement the cam surface 72 releases the blocking contact 71 and the latter closes the circuit for the connected members of the washing machine, such as the inlet and outlet valve, the heating, etc.

FIG. 8 also shows that, in order to reduce production costs for a programme selector switch according to the invention, the

discs

57, 58 may be in the form of toothed wheels, through which the

rotary wipers

5, 12 of the intermittent switching and the time mechanism are driven by the motor 17.

FIG. 7 shows a modified embodiment of a blocking device. This comprises a switching pawl 83, for example a metal plate 1.5 to 2 mm. thick, having a narrow straight 7 portion 84 adjoining a segmental almost r'ectangularly curved arcuate portion 85. The straight end of the armate portion is bent downwardly at right angles and designed as a blocking pawl 86. At the free end of the pawl 86 is a widened projection 87 co-operating with the

stops

60, 59 on the

rotary discs

57, 58. Near the end and substantially on the centre line of the straight portion 84 of the pawl 83 is a slot 89, into which a guide pin 90 projects, the pin having sufiicient clearance from. the width of the slot 89 to enable these parts to move relatively to one another. The guide pin 99 is mounted perpendicularly on the wall 65 of the housing. At the place where the straight portion 84 ends and the arcuate portion 85 begins, the edge of the pawl 83 away from the direction of curvature of the arcuate portion 85 is extended in a straight line and forms a sliding projection 91 with a slidin edge 92, which is adjoined at right angles by an abutment ed e 93, which intersects the outer curved edge 94 of the a ruate po tion 95 at this obtuse angle. The three edges 9'2, 93, 94 coo erate with a supporting pin 95 mounted peipendieularly on the wall 65 of the housing. At the edge of the straight portion of the pawl -83 facing the direction of curvature of the arouate portion 85 is an elongated slit 96 substantially parallel with thisedge. An elongated narrow stamped member stands upright on a switching pawl 83 at an obtuse angle to the centre line through the straight portion 84 and forms a lever 97 for operating the blocking contact. Approximately in the centre of the outer curved edge 94 of the arcuate portion 85 and in the immediate vicinity of the edge is a hole 98, into which is hooked a tension spring 99 acting substantially radially of the centre of curvature of the arcuate portion $5. FIG. 9 shows the position or these members of the switching pawl s3 immediately before the beginning of a new art of the programme. At this stage the stop 59 of the intermittent switching mechanism is at an angle to the stop 66 of the time mechanism, and the marginal edge of the widened projection 87 on the blocking pawl 86 bears on the stop so of the time mechanism. In this position the switching awl 83 has been raised against the pull of the spring 99 in the direction of the arrow A until the sup porting pin 95 is at a right angle between the sliding edge and the abutment edge 93. At the beginning of a new part of the washing programme, the stop 59 of the intermittent switching mechanism remains in known manner in the position shown in FIG. 9, while the stop 60 of the time mechanism, starting from. the angular position relatively to the stop 59, sets out on its rotary path in the direction of the arrow B. In the course of this movement the stop 60 releases the marginal edge of the widened projection 37 so that the latter and thus the pawl 83 are moved by the spring 99 in the direction of the arrow C, until the pawl 83 bears on the supporting pin 95 at the angle between the arcuate edge 9d and the abutment edge 93. The switching pawl is then in the position shown in FIG. 10.

At the beginning of a passing over step both the stop 59 of the intermittent switching mechanism and the stop 60 of the time mechanism move at the same rotary speed in the direction of the arrow B, in known manner, the two stops remaining in the same relative angular position while they are rotating together. At the beginning of a passing over step, therefore, instead of the marginal edge of the widened projection 87 sliding off the stop 69 and moving in the direction of the arrow C together with the switching pawl, it is immediately engaged by the stop 57 of the intermittent switching mechanism and moves in the direction of the arrow D, until the guide pin 90 contacts the inner end of the slot 89 and the supporting pin 95 the end of the sliding edge 92, thus preventing any further movement in this direction. In this position the slit 96 coincides with a recess 109 in the wall 65 of the housing and a latching means, to be described hereinafter, Springs gh the Slit 96 into a recess 199 and prevents the switching pawl from being drawn into the position shown in FIG. 10 by the spring 99 when the widened projection 87 has been released by the stop 59 of the intermittent switching mechanism. In this latched position shown in FIG. 11 the lever 97 for operating the switching pawl 83 presses against the blocking contact 71, opens it and keeps it open for the duration of latching. As a result of the opening of the contact 71, the main circuit for the connected members of the washing machine, such as the inlet and outlet valve, the heating, etc., is broken, and these members do not respond while their programme contacts are momentarily closed during the passing over steps.

FIG. 13 shows an example of the latching device, which in this example comprises a T-shaped leaf spring 191, of which the web and the left-hand longer side of the beam are fixed to the switching pawl in a suitable manner, for example by rivets 102 near their ends. The shorter right-hand side of the beam is bent at an acute angle to the centre line of the beam and at right angles to the plane of the leaf spring, and extends through the slit 96 through the pawl 83 and beyond the plane of the underside of the latter. The right-hand, shorter side of the beam of the leaf spring 191 has a lateral projection 103 which, in the position shown in FIG. 11, is above the end of the lever of the unlatching device, which lever projects through an opening 79 in the housing wall 65, so as to unlatch the pawl 63 and thus close the blocking contact 71 in known manner at the end of the passing over steps.

FlG. 14 shows in section how the switching pawl 83 is latched by means of the angled end of the shorter right-hand beam of the leaf spring 101. At the beginning of and during a part of the programme the switching pawl adopts a position relatively to the wall 65 of the housing, such that the recess in the guide track and the slit 96 in the pawl 83 cannot coincide (see FIGS. 9 and 10). Thus the lower edge of the angled end of the shorter right-hand beam of the leaf spring 101 slides along the wall 65 as shown in broken lines in FIG. 14, and the leaf spring 101 is raised from the top of the pawl 83. It is only in the FIG. 11 position, during the passing over step, that the slit 96 in the pawl 83 and the recess 100 in the housing wall 65 coincide, and the end of the angled shorter beam of the leaf spring .61 can engage in the recess 100 in the wall 65, following the pressure of the spring, and latch the pawl 33 in this position. The latching remains effective until, at the end of the passing over steps, the end of the lever 80 of the unlatching device is moved upwardly through the opening '79 in known manner and forces the lateral projection 193 on the leaf spring 101 upwardly, whereby the angled end of the shorter right-hand beam is withdrawn from the recess 100. The unlatched pawl 83 moves, following the pull of the spring 99, into the FIG. 9 position and during this movement releases the blocking contact 71, which closes and reforms the interrupted circuit for the various members of the washing machine.

FIG. 15 shows how the pawl 83 can, in one operation, be stamped from a piece of metal plate as a form cut with all its constructional features, ready to be trimmed along the broken lines in FIG. 16 at a successive stage.

I claim:

1. A program selector switch for electric washing machines, comprising an intermittent motor-driven switching mechanism operating program contacts in steps, time mechanism controlling said switching mechanism according to the desired duration of the preselected part of the washing program, blocking means operated by said switching mechanism, said blocking means comprising a blocking contact mounted in series with the program contact, said blocking means opening said blocking contact when said switching steps follow immediately on one another and when omitted parts of the program are passed over by preselection, means latching said blocking contact in open position, and means unlatching said blocking contact at the beginning of a new part of the program.

2. A program selector switch according to claim 1, said unlatching means comprising an angle lever mounted to pivot about a point intermediate its ends, said intermittent switching mechanism having a common drive motor having an armature shaft, and one free end of said lever being spring-pressed perpendicularly against the end of said armature shaft.

3. A program selector switch according to claim 2, a switching pawl having a lateral projection, said lateral projection being located over the other end of said angle lever when the pawl is engaged.

4. A program selector switch according to claim 1, said blocking means comprising a flat, movably mounted switching pawl, and a blocking pawl rigidly attached to said switching pawl.

5. A program selector switch according to claim 4, said flat switching pawl having a narrow straight portion joining a segmental curved portion of substantially the same width.

6. A program selector switch according to claim 5, said straight portion of said flat switching pawl having a slot therein, and a guide pin mounted to operate perpendicularly therein.

7. A program selector switch according to claim 1, said intermittent switching mechanism including two rotatable circular discs, a separate shaft for each of said discs, one of the shafts being hollow and concentrically mounted about the other shaft.

8. A program selector switch according to claim 7, a stop on one of said circular discs having a path of rotation, said blocking pawl projecting into said path when omitted parts of the program are passed over.

9. A program selector switch according to claim 7,

10 wherein each of said discs have teeth on the periphery thereof for selectively engaging the armature of said motor.

10. A program selector switch according to claim 5, said blocking contact carrying actuating pin and said switching pawl having a cam surface mounted to contact said pin and operate said blocking contact.

11. A program selector switch according to claim 1, said blocking means having a rotatable spring tensioned blocking pawl, a switching pawl articulated to said blocking pawl, a guide track carrying an upwardly projecting latching pin, and a spring pressing said switching pawl against said guide track.

12. A program selector switch according to claim 11, said time mechanism having a rotary member, a stop on said member, and said stop contacting said spring tensioned blocking pawl.

13. A program selector switch according to claim 11, two rotatable circular discs mounted in parallel planes, one above the other, and spaced to provide a gap, said blocking pawl projecting into said gap and mounted to rock in a plane parallel to the planes of the discs.

14. A program selector switch according to claim 13, the facing surfaces of said circular discs having stops mounted thereon, and said tension spring of said blocking pawl being mounted substantially tangential to the paths of the stops on said circular discs.

References Cited by the Examiner UNITED STATES PATENTS 3,110,777 11/1963 Rast 200-38 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.