US3535896A

US3535896A - Safety interlock for the access door of washing and the like machines

Info

Publication number: US3535896A
Application number: US768798A
Authority: US
Inventors: Alan K Brown; Gordon L Fair
Original assignee: British Domestic Appliances Ltd
Current assignee: British Domestic Appliances Ltd
Priority date: 1967-10-25
Filing date: 1968-10-18
Publication date: 1970-10-27
Anticipated expiration: 1987-10-27
Also published as: GB1222826A; DE1804499A1; FR1589978A

Description

Oct. 27, 1970 A. K. BROWN ET AL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND 4 THE LIKE MACHINES Filed Oct. 18 1968 6 Sheets-Sheet 1 n7 na- Oct. 27, 1970 A. K. BROWN ET AL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS vDOOR OF WASHING AND THE LIKE MACHINES Filed Oct. 18. 1968 6 Sheets-Sheet 2 Oct. 27, 1970 A. K. 5mm E ZT AL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND THE LIKE MACHINES 6 Sheets-Sheet 3 Filed Oct. 1 8. 1968 3 2 1 I W Q. Q I 8 1% fi s Q ll J $7: 1 n: N :v Q 4 2 H mm MELT :EIWS T a 6 N o 1| o itilfiqiwlt Q H L 8m 2 a 8 3 S 3M 2 A. K. BROWN L Oct. 27, ,1970

SAFETY INTERLOCK FOR THE ACCESS DOOR 0F WASHING AND' THE LIKE MACHINES 6 Sheets-Sheet 4 Fild 001;. 18. 1968 Oct. 27, 1970 A. K. BROWN ETAL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHINGAND THE LIKE MACHINES Flled Oct. 18, 1968 6 Sheets-Sheet 5 gl03 NR3 S'W'd' 63 7e In l m 426a 4b 1' A. T

2O x i 4 7 Wash Winding 7 v Ls A I I 7E 3.: N Fig) 65 DoorSwifch 06:. 27, 1970 A K. BROWN ETAL 3,535,896

SAFETY INTERLOCK FOR THE ACCESS DOOR OF WASHING AND THE LIKE MACHINES Filed Oct. '18, 1968 6 Sheets-Sheet 6 United States Patent US. Cl. 6812 6 Claims ABSTRACT OF THE DISCLOSURE A clothes washing or other machine, of the kind in which articles to be treated are placed in a drum provided with an access opening and the drum is rotatable by an electric drive motor comprising an automatic programme sequence control, an interlock arranged to prevent opening of the door, as by preventing operation of a door opening knob, except when a selected operation has been completed, a manually operable control knob for by-passing an operation, as by accelerating movement of a face cam normally driven by a timer motor of the automatic programme sequence control, but only up to a period before the end of the by-passed operation, at which stage the manually operable means becomes ineffective for that purpose and the remainder of the operation is controlled by the timer motor, this period corresponding to that for the drum to come to rest and liquid to be pumped from the drum to enable safe opening of the door.

BACKGROUND OF THE INVENTION This invention relates to washing machines, spin dryers or like machines in which articles to be treated are placed in a drum provided with an access opening and rotatable by an electric drive motor.

Such machines are normally provided with a door hingedly connected to an outer housing of the machine and a fastening device on the door is arranged to cooperate with a safety latch on the housing so that the door cannot be opened unless operation of the machine has first been interrupted or terminated. Such a safety arrangement often comprises a solenoid actuated lock energised in parallel with the drive motor for the drum and operating so that when the drive motor is deenergised the door can be opened. This arrangement is not entirely satisfactory as it is possible to open the door while the drum, although decelerating, is still rotating at a comparatively high speed.

In machines, such as washing machines of the horizontal type, in which treatment of clothes consists of a series of operations performed in a drum rotating on a horizontal or substantially horizontal axis, the drum having an access opening, normally closed by the door in one wall, there is a further disadvantage in that liquid from the drum may be spilled if the door is opened during rotation of the drum. The operation of such machines, particularly washing machines, is usually controlled by a sequence control, i.e. electrical devices included in the machine are connected via a mechanism comprising a plurality of switches, to a source of electricity supply, and the switches are actuated either in sequence by automatic means or, manually if it is desired that any operation in the sequence be terminated or omitted. It is usual therefor to provide a door interlock coupled to the sequence control, such that the door remains locked in all positions of the sequence control except those where the drum should be empty of liquid and stationary. In providing this alternative control, however, it is possible by manual advancement of the switches 3,535,896 Patented Oct. 27, 1970 through their set sequence to a point where the door is unlocked for the door to be opened either with the drum rotating at high speed, or containing liquid, as insufiicient delay is then provided for the drum to come to a rest, or be drained of liquid.

SUMMARY OF THE INVENTION An object of this invention, therefore, is to provide a safety interlock for the access door such that these disadvantages are overcome. I

According to the present invention in a washing machine, spin dryer or the like machine in which articles to be treated are placed in a drum provided with an access opening and rotatable by an electric drive motor, the drum opening being fitted with a door, there is provided an automatic sequence control which is also capable of man ual actuation in order that an operation or operations may be by-passed, an interlock being arranged to prevent opening of the door at all times, except when each or a series of operations have been finally completed, by inclusion of means on manual operation providing a delay period sufficient to allow the door to be opened safely, and the arrangement being such that manual actuation of the control is rendered ineffective to override this delay period as by ensuring that the last part of the operation or operations by-passed is controlled by a timer motor.

Since the invention is of particular value in its application to clothes Washing machines particularly of the horizontal type, i.e. in which treatment of the clothes is carried out in a forarninous electric motor driven rotatable drum, whose axis is horizontal or substantially horizontal, and which drum is mounted within an outer coaxial wash liquid containing drum suspended in a cabinet by means of springs and dampers its applications thereto will now be further described.

A typical series of treatment operations in such a machine may consist of: a washing period, in which the clothes drum is rotated for substantially equal periods of time in each direction to tumble the clothes in contact with a washing liquid contained within the outer drum; a spinning period, during which the clothes drum is rotated at high speed in one direction only to centrifugally extract the washing liquid from the clothes, a pump being used to remove the resulting liquid from the drums; a rinse period, the operation being similar to that during the wash period but the washing liquid being replaced by Water, with or without a rinsing additive; and a final, further spin drying period. Such a programme can be effected by a sequence control mounted in the machine cabinet which, by means of switches sequentially actuated in response to movement of a synchronous electric timing motor, causes energization of the drive motor(s) and other ancillary electrical components of the machine to perform the programme as laid out. Associated with the sequence control may be a scale on which an indicator, connected to the timer, presents the progress of the programme.

A door latch mechanically operated by a button on the control panel of the machine is arranged to be locked by the sequence control at all times except when it is safe and desirable to open the door, i.e. when the drum is stationary and empty of water. A setting knob associated with the control also allows manual advancement of the sequence at all times except to immediately prior to any point where the control would permit operation of the door latch to open the door. At these points the knob is arranged to be disengaged and the control advances independently for a predetermined period so providing the delay in which the rotating inner drum can come to rest giving time for any liquid present in the drums to be removed by the pump before the door can be unlatched.

- 3 BRIEF DESCRIPTION OF THE DRAWINGS Reference will now be made by way of example to the accompanying drawings, in which:

FIG. 1 is a front view of a horizontal washing machine with its access door closed.

FIG. 2 is a part plan view of the washing machine of FIG. 1,

FIG. 3 is a part sectional elevation of FIG. 1 of the washing machine.

FIG. 4 is a bottom plan view of a control panel of the washing machine of FIG. 1 with its electric motor operated sequencer timer omitted,

FIG. 5 is a vertical side-to-side cross section of part of the control panel of FIG. 4 showing the electric motor operated sequence timer and its control knob,

FIG. 6 is a perspective view of a part of the sequence timer,

FIGS. 7 & 8' are sectional bottom plans of further detailed views of the control of FIG. 5,

FIG. 9 is a vertical front-to-rear section of part of the access door of the machine and its associated latching mechanism,

FIG. 10 is a circuit diagram of the washing machine, and

FIG. 111 is a time cycle chart of the washing machine programme.

In FIGS. 1-3 there is shown a horizontal washing machine comprising an outer liquid container 101 mounted on four damped spring suspension legs two only of which are shown at 102 within an outer cabinet 103-, and an inner perforate horizontal clothes drum 104 mounted for rotation on a spider 105 at the rear of the drum 104. The spider 105 is rigidly secured to a driven shaft 106 rotatable in horizontal spaced

bearings

107, and 108 in a bearing housing 1109 secured to the rear of the liquid container. The arrangement of the spaced

bearings

107, 108 acting on the drive shaft 106 allows the drum to be supported at that, Le. the 'back, end only. The driven shaft 106 carries a pulley 110 drivingly secured to it. A drive belt 111 of V section extends round the pulley 1'10 and a pulley F112 carried by an output shaft 113 of a two-speed electric induction motor 114 which is supported at each end of its casing by means of

suspension units

115 and 116 from the lower part of the outer liquid container 101. Access by a user to the clothes drum 104 is obtained through a front door 117 hinged at 118 and 119 (FIG. 1).

Liquid is supplied to the

drums

101 and 104 through an electromagnetically actuated water inlet valve 120 (FIG. 3). A liquid level responsive switch 126A shuts the water inlet valve when the water level in

containers

101 and 104 reaches the required level and initiates actual washing. Liquid in the drum is heated where required by the programme sequence by a sheathed wire electric resistance heater 121 mounted towards the bottom of the drum 101 and is removed from the drum 101 by a pump 122 driven by its electric motor 123 through a pipe 124 only partly shown in FIG. 3, but extending from the rear bottom of the drum 101 to the pump 122.

A washing machine control panel 125 is provided on the top of the washing machine at its front and includes a sequence timer 1 (FIG. 5) having a synchronous electric driving motor 2, which in operation rotates through a set of pawls and gears in a gear case shown at 4, a shaft 5 in a stepwise fashion. Successive steps conveniently occur at intervals of two minutes to enable easy and accurate allocation of active periods of a programme of the washing machine. A face cam 6 mounted on the shaft 5 to rotate with the shaft so as to selectively energise and de-energise various electrical components of the washing machine through switches indicated generally at 7 such that it will perform the operations described in the preamble hereto.

A disc 8 is also fixed to the shaft 5 and rotates with the shaft and has a form as more clearly shown in FIG. 6,

including an annular flange 8a and gear teeth 9; the various functions of this disc will be described hereinafter. A manual control knob 10 for the timer 1 is rotatably mounted on the shaft 5 and retained thereon by a locknut 11 and a circular trim member 12 decoratively covers the otherwise open front of the knob. The control knob 10 has four radial projections shown at 10a (FIGS. 5, 7 and 8) which act in conjunction with a lever 13 of semirigid material, such as nylon, of the form shown in FIGS. 7 and 8. and pivotally mounted on a pin 14- on the underside of disc '8. One end 13b of the lever 13 is attached to a coil tension spring 15 the opposite end of which is anchored at pin 15a so that the other end 13a of the lever is capable of limited movement in an arcuate manner about the pin 14 thus under the restraining influence of the spring 15.

A projection 16 on the arm 13a of the lever passes through a slot 17 in the disc 8 (see also FIG. 5) so as to co-operate with one or the other of the projections 10a. A further part 18 of the lever 13 is arranged to engage with an internal surface 19a of an annular cam 19 and in particular with recess. 1%.

The gear teeth 9 formed around part of the periphery of disc 8 (FIGS. 4, 6, 7 and 8) engage with teeth of similar form on a gear wheel 20 (FIGS. 4 and 5) which is ro-- tatably mounted on a pin 21 attached to a control panel supporting plate 22.

A drive cord 24 (FIG. 4) for a scale indicator pointer 25' passes round the periphery of a drum 26 integral with the gear wheel 20 and is secured thereto. The drive cord 24 slidably passes over

pins

28a, 28b, 28c and 28d (FIG. 4) which are fixed to the control panel supporting plate, to a pulley 30 attached to a tensioning spring 31 and from the pulley 30 the drive cord 24 returns to the pin 28d to which it is secured. The pointer 25 is fixedly secured by turned over projections on the pointer 25 to the portion of the drive cord 24 between pins 28b and 280 and overlies a scale 33 marked with indications of the various selectable programme of the washing machine.

The upstanding annular flange 8a of disc 8 (see FIGS. 48) has a portion 8b cut away sufficiently to allow introduction of a latch 35 (FIG. 4) of a lever 36 pivoted on a pin 37 on the control panel supporting plate 22. The lever 36 is formed from a semirigid material, such as nylon, and has a portion 38 of thinner crosssection forming a spring which bears against an upturned portion 22a of the supporting plate in a manner such that the latch 35 is urged away from the annular flange 8a. The lever 36 is also pivotally connected at 36:; to one end of a rod 39, the opposite end 390 of which is pivotally attached to one arm of a bell crank 40 pivoted on a pin 41 on the supporting plate. The other arm of the bell crank 40 is pivotally attached to a further rod 42 at 42a an opposite end 42b of which carries a shorter arm of a lever 43, pivoted on a pin 44 on the supporting plate. The longer arm of the lever 43 has attached thereto, close to the pivot point 44, an inner wire of a Bowden cable 45, which is anchored to the supporting plate by a bracket 46-. The longer arm of the lever 43 also bears on a knob 47 (FIGS. 2 and 4) accessible from outside and slidably held within an open ended box 48 secured to the supporting plate.

The other end of the Bowden cable 45 is connected to a latching arrangement 126 for the washing machine door as shown in detail in FIG. 9. A latch arm 49 of the latching arrangement is pivoted at 4911 in a moulded housing 51 secured by nuts and bolts 52 to the front wall of the machine shown in part at 103. The latch arm 49 engages at one end with a latch plate 54 which is formed integrally with an inner panel 56 of the washing machine door 117 as shown in FIG. 9. A rubber resilient sealing gasket 58 is provided between the door and the front wall 103. The connection to the latching arrangement is by the Bowden cable inner wire 45a being connected to the end of the latching arm 49 opposite the door, while the outer casing 45b of the cable is secured to the moulded housing 51. A spring 59 retains the latching arm 49 in the position shown in FIG. 9 until actuated by the Bowden cable.

The control panel carries a further knob 60, held captive in the same manner as knob 47 by a box 61, which box is equipped with a latching spring 62 and is arranged to operate a microswitch 63 secured to the supporting plate 22 by screws 64. The microswitch 63 controls a step in the programme as will be described hereinafter.

To load the machine with articles to be washed etc. the access door 117 is opened by pressing the knob 47 to pivot the lever 43 about its pivot 44, thereby actuating the Bowden cable 45 so as to rotate the latch arm 49 in an anti-clockwise direction and release the latching arrangement to allow the door 117 to spring open under the influence of the resilient gasket 58. The pivoting of the lever 43 simultaneously shifts rod 42 so as to rotate the bell crank 40 and supply a compressive force to the rod 39 causing the lever 36 to rotate in a clockwise direction (in FIG. 4). As a result, the latch member 35 is moved into the cut out 8b in the annular flange 8a.

The clothes to be washed can be inserted into the inner rotatable, drum 104 and the access door 117 closed compressing the gasket 58 and re-engaging the latch plate 54 with the latch arm 49. A washing operation is started by (rotating the timer knob clockwise to the desired programme position thereby locking the door and then) pulling the timer knob 10 outwards thereby closing an isolating switch 65 (FIG. 10) associated with the timer so as to supply electrical power through that one of the switches 7 closed by the face cam 6 to start the timer motor 2 i.e. 7a.

The timer motor 2 commences to rotate the shaft 5 and with it the face cam 6 and disc 8 in a stepwise motion at intervals of 2 minutes, the shaft 5 performing one complete revolution in the course of a normal programme. The first programme step is such as to rotate drum 8 from the position shown in FIG. 4 so that the cut out 8b in the annular flange 8a ceases to coincide with the latch 35 and movement of the knob 47 inwardly to actuate the door unlatching mechanism is thereby baulked by engagement of the latch member 35 against the annular flange 8a. The door cannot therefore be unlatched throughout the programme until the cut out 8b again coincides with the latch 35; such coincidence only occurring at the end of the programme i.e. when the machine is deenergised. The first stepwise motion of the shaft also causes face cam 6 to close that one of the switches 7 necessary to commence the programme i.e. switch 7a to open the water inlet solenoid valve.

If the programme of the machine is not now manually altered by a user, operation of the timer will cause the machine to carry out its set programme as illustrated in the timer cycle chart FIG. 11 and as determined by the rotation of the face cam 6 and the distribution of the switches 7 and circuit FIG. 10. The progress of the pro gramme is recorded by movement of the pointer 25 as it is moved by the cord 24 in accordance with movement of the gear and hence with the movement of the disc 8. As the programme proceeds the pointer 25 traverses the scale 33 and the spring 31 is tensioned. Four minutes, or two steps, before the end of the programme, i.e. the last two minutes of spinning, followed by deenergisation of the drive motor the clothes drum coasts to a halt, a drain pump remaining energised to ensure removal of free liquid from the drums. At the end of the programme the last stepwise motion of the shaft 5 rotates the disc 8 to a position in which the toothed portion 9 disengages from gear 20 due to a gap in the gear teeth on disc 8 and the pointer 25 is thus returned to its original position under the influence of spring 31. The same last step deenergises the drain pump and also brings the cut out 8b once again into line with the latch 35 to permit unlatching of the access door 117 of the machine so as to allow removal of the washed clothes.

If, for any reason, the user wishes to by-pass any particular operation in the programme this is achieved by first pushing knob 10 inwards, thereby opening the switch 65 and de-energising the machine. The knob can then be rotated in a clockwise direction causing the radial projection 10a to engage with the projection 16 of lever 13 in FIG. 7; this projection 16 is therefore urged in a clockwise direction and thus acts against the pivot pin 14 causing the disc 8 and hence the timer shaft 5 to rotate with knob 10. The programme is thus advanced in response to the rotation of the printed circuit board 6, the pointer 25 moving to indicate the progress through the programme. When the desired operation is reached the knob 10 is pulled outwards to close the switch 65 and the programme is thereby re-started at a selected point. If the user desires to terminate the programme before it has run its course this can be achieved by pushing the knob 10 inwards to deenergise the machine and by rotating the knob 10 to move the programme towards its completion as described above.

In both these cases, in order to ensure that the access door 117 is not opened before the clothes drum 104 has coasted to a halt or before the drain pump 122 has removed all the water from the drums, a delay period is introduced at the end of the programme sequence during which the access door 117 cannot be unlatched. This is achieved by providing that as the programme progresses towards its completion, part 18 of the lever 13 is urged by spring 15 into recess 19]) four minutes or two steps, before the end of the programme. The lever 13 thus moves outwards and projection 16 no longer co-operates with radial projection 10a on the knob 10 which is thus free to rotate on shaft 5 without influencing the programme sequence. The last four minutes of the programme are thus controlled entirely by timer motor 2 and cannot be by-passed or terminated by movement of the control knob. By this means it is ensured that the rotating clothes drum has ample time to coast to a halt and that the drain pump 122 has cleared the

drums

101 and 104 of washing liquid before the timer shaft 5 rotates to bring the cut out 8b into coincidence with the latch 35 and thus permit the door to be opened by operation of the knob.

While the programme sequence described provides only one position in which the door may be unlatched, the construction of member 8 may be altered to permit the access door 117 to be opened at various other points in the programme, where it is safe to do so. For example, a period could be incorporated immediately before the rinsing operation, during which the door could be opened for the insertion into the drum of clothes requiring only a single washing or rinsing operation, additional cut outs being incorporated in member 19 to disconnect the knob 10 at least one programme step before the end of the previous period as before.

For clothes which should not be spin dried the knob 60 is provided, which, when operated so as to actuate the microswitch 63, prevents rotation of the drum at spinning speed by overriding the controller which would otherwise cause energisation of the drive motor at spinning speed. Operations in the programme sequence normally designated for spin drying are thus, by operation of the knob 60, devoted only to removing, by means of the drain pump, water which drains from the clothes during that period.

If the invention is to be applied to a vertical washing machine, in which the washing operation is performed in a drum with a vertical axis, by agitation of the clothes and washing liquid by a reciprocating paddle or rotating impellor, and in which drying is performed by high speed rotation of the drum about its vertical axis, then the cut out in the annular flange 8a can be extended to permit unlatching of the access door at all times except during the actual spin drying operations and one programme step thereafter in which to permit the rotating drum to coast to a stop. There is no risk of water escaping in such a machine, if the access door, which is normally at the top of the machine casing is opened during the washing operation.

An application of such a safety feature to a machine intended solely for centrifugally drying clothes by fast rotation about a vertical axis could also be provided for by a controller having only a single control switch, for a motor in conjunction with a door interlock and a knob disengaging device as already described.

Although the time intervals (FIG. 1) are conveniently 2 minute ones other intervals may be used, e.g. 1% minutes.

What we claim is: I

1. A machine of the kind in which articles to be treated are placed in a drum provided with an access opening and the drum isrotatable by an electric drive motor, comprising an automatic sequence control, an interlock arranged to prevent opening of an access door fitted to tion prior to the end of the bypassed operation, the knob the drum opening except when a selected operation has been completed, and manually operable means for bypassing an operation, in which time delay means are provided which prevent release of the interlock until a safe period after the manually operable means has been used to by-pass the operation.

2. A machine as claimed in claim 1, in which a latch for the door is mechanically operable by a button on a control panel of the machine and the interlock prevents operation of the button except when it is safe and desirable to open the door.

3. A machine as claimed in claim 1, in which the manually operable means is arranged to accelerate movement of a timing part normally driven by a timer motor of the automatic sequence control but only up to a period before the end of the bypassed operation, at which stage the manually operable means become ineffective for that purpose and the remainder of the operation is controlled by the timer motor. 1

4. A machine as claimed in claim 3, in which a programme setting knob and associated parts constitute the manually operable means and they are arranged in a condition of the knob to advance the sequence to a posithen being ineffective to advance the programme.

5. A machine of the kind as claimed in claim 4, in which the programme setting knob is in the condition set forth in claim 4, arranged to initially open a main switch deenergising the machine and on further movement cooperating abutment surfaces, one being movable by the knob and the other being provided on a timing shaft of the sequence control are arranged to engage so as to accelerate the timer through an operation, means being provided which before the end of the operation disengage the drive from the timer shaft so that the knob turns freely without overriding the operation which is then under control of the automatic sequence control.

6. A machine as claimed in claim 1, in which the drum is arranged to rotate about a horizontal or substantially horizontal axis and the drum is arranged to contain liquid for treating the articles in the drum and, in which the delay period provided after the operation of the manually operable means to bypass the sequence control is such as to allow both the drum to come to rest and for any liquid present to be removed by a pump before the door can be unlatched.

References Cited ROBERT L. BLEUTGE, Primary Examiner US. Cl. X.R.

4/1966 Switzerland.