US3117434A

US3117434A - Washing machines

Info

Publication number: US3117434A
Application number: US132238A
Authority: US
Inventors: George M Byrd; John S Miles
Original assignee: Associated Electrical Industries Ltd
Current assignee: Associated Electrical Industries Ltd
Priority date: 1960-08-19
Filing date: 1961-08-17
Publication date: 1964-01-14
Anticipated expiration: 1981-01-14

Description

Filed Aug. 17, 1961 Jah. 14, 1964 G. M. BYRD ETAL 3,117,434

WASHING MACHINES 5 Sheets-Sheet 1 /NVENTOA G o Maxw B ra' e fgey. Mw

a i. o '4222 ATTORNE Y Jan. 14, 1964 Filed Aug. 17. 1961 o o 1f 27 G. M. BYRD ETALv 3 Sheets-Sheet 2 |2'| n J BL 'ai .,n 1 t 4 les I Il'.

Il /l wwf-NTO@ A TTU/PNE Y Jan. 14, 1964 G. M. BYRD ETAL 3,117,434v

WASHING MACHINES Filed Aug. 17, 1961 3 Sheets-Sheet 3 /N VEN TOR Gleorge Mgxwe/l ,gy

Trb/@viv United States PatentA O 3,1l7,434 iF/ASHENG MASHlNES George M. Byrd and lohn S. Miles, Peterborough, England, assigner-s to Associated Electrical Industries Limited, London, England, a British company Filed Aug. 17, 1961, Ser. No. 132,238 Claims priority, application Great Britain Aug. 19, 1960 13 Ela-inns. (Cl. 68-1349 This invention relates to machines for washing clothes and 'the like of the kind in which an agitator is mounted with its axis substantially vertical within a washing bowl th agitator being oscillated to and fro about its axis to cause relative movement between the water, the clothes the bowl to produce a washing action.

lt is known in machines of this kind to provide an agitator having a core the diameter of which increases towards the base, vanes projecting from the core serving to produce the desired relative motion. In order to cause the clothes to circulate through the washing liquid at the same time as they are agitated the vanes are not usually straight do not extend in axial planes but are curved with the result that the clothes circulate downwardly adjacent the agitator, radially outwardly at the bottom of the bowl upwardly adjacent the bowl periphery.

One proposed construction of agitator has a generally conical core with the vanes arranged in a spiral about the core each of the vanes in axial section being inclined upwardly with respect to a normal to the axis of the agitator, the inclination increasing from the top of the agitator towards the bottom. In the known agitators of the proposed construction the vanes are found to exert a positive thrust upon the contents of the bowl in one direction of rotation and slip through the washing liquor in the opposite direction without exerting a positive thrust upon the bowl contents, and it was claimed that this was the result o the vane formation above dened.

lt is an object of the present invention to provide a wasnmg machine of this kind which is more efficient than those or known construction in that definite movement of the contents of the bowl is obtained on both forward and reverse movements of the agitator, both of the movements of contents being in the same direction. Moreover the bowl of the machine and the quantity of washing liquor required for a given load of washing and size of agitator can be smaller than in known machines of a similar hind.

it is a further object of the invention to provide a washing machine agitator which is simple to manufacture in that it may be removed from a mould without splitting the mould an axial plane.

According to the invention in a washing machine including a howl and an oscillatable agitator disposed upright substantially in the centre thereof, the agitator comprises a central core tapering from the base towards the upper end, and at least two vanes set in a steep true helical formation having a constant generatrix of constant form in relation to the axis o oscillation disposed so that in section on planes normal to the axis of oscillation a line joining the tip of the vane to its intersection wit the core has an a or" lead to the radius through the intersection with the core which is in the direction of the hand of the helix and the vanes being of such a width that the outer edges lie substantially on a conical frustum hut are rounded oft at the lower end.

it desired the yanes in section on planes normal to the axis oi oscillation may be curved so that the angle of lead increases towards the tip.

Alternatively the agitator may comprise a central core apering from the 1oase towards the upper end, and at east two varies set in a steep true helical formation and being disposed so that in section on planes normal to the lllAS/l Patentes aan. i4, 1aed ICC axis of oscillation they extend tangentially to an imaginary cylinder co-axial with the axis of oscillation, the angle of lead to the radius being in the direction of the hand of the helix and the vanes being of such a width that the outer edges lie substantially on a conical frustum but are rounded oft at the lower end. In this case the generatrix of the helix is a straight line having a constant relationship to the axis of oscillation.

ln determining the precise envelope of the outer edges of the vanes it is best to start from a true conical frustum and modify it slightly to give the best results. The actual form will depend upon the shape of the bowl, the intended washing load of a machine and similar factors, but will not depart much from a true conical frustum and the term substantial is intended to cover such departure. lt will be found that in many cases the centre third of the vanes should be cut away to a slight degree to improve the circulation of the clothes being washed in the wash liquor.

As a result of the true helical formation having a generatrix of constant form in relation to the axis of oscillation the intersection between any cylinder coaxial with the agitator and the vane will be a true, i.e. constant pitch, helix. As a result a vane of this form and therefore the complete agitator can be withdrawn from a mould unsplit mould in any axial plane by an unscrewing action from the base of the core. The rounding olf of the vanes produces a reentrant at this end which will involve a split in the mould in a transverse plane, but the mould must in any case be opened and can easily be arranged to separate on the appropriate transverse plane. This explanation ignores the thickness of the vane but provided this is constant or in practice decreases slightly from the base upwards, no essential difficulty will arise.

lt also follows that since the core tapers the intersection between the vane and the core will not be a true helix but will present a pitch angle which increases from the base upwardly. lt also follows that where the blades are curved the portion of the blade extending outwardly of the core will not be of constant form. The constant generatrix of the blades is related to the axis of oscillation and the cone shaped core will intersect different points of the generated curve of the blades at different heights of the agitator. Also where in horizontal section the vane is straight and tangential to the aforesaid imaginary cylinder, the angle between the radius and the intersection of the blade section with the core, i.e. the lead angle of the blade also increases upwardly. ln general it is desirable that the lead angle should be as great as possible but the angle cannot be made greater at the base than a value determined by the general proportions of the agitator because the vane would become tangential before the top of the core was reached. In other words the maximum possible lead angle, i.e. of will be attained if the imaginary cylinder is of the same diameter as the core at they upper end. In a preferred construction the lead is somewhat less than the maximum possible, the angle increasing from 10 or 11 at the base to 60 at the top. A short part of the core at the top may be cylindrical and the lead angle will then be constant over this part.

Whilst the vanes according to the present invention will be inclined upwardly with respect to a normal to the agitator as called for in the prior proposed construction referred to, the form of the vanes in sections normal to the axis of oscillation was not delined. Vanes in accordance with the definition given do not necessarily have a forward lead but could in sections normal to the axis of oscillation extend radially to the core or have an angle of lead to the radius of opposite hand to that of the helix,

ln the operation of a washing machine according to the present invention the agitator oscillates about its axis through an angle of between 187 and 230 and upon rotation of the agitator in one direction an article suspended in the wash liquor is moved spirally outwardly from the region of the bottom of the agitator whilst the reverse rotation of the agitator produces a definite down feed action which will move a further article downwardly adjacent the agitator into the position initially occupied by the iirst article. The lower region of the Vanes is largely responsible for the rst mentioned movement whilst the second is largely caused by the uppermost portion of the varies. The main washing action takes place in the lower region of the bowl.

The core of the agitator is of conical shape with its lower end enlarged to a dish shape.

The number of vanes, which must not be less than two, depends on the size of the agitator because the average size of the articles to be washed does not vary and the space between the vanes is related to the size of the articles. In an average size machine there would be three and in most machines of a size suitable for domestic use there would be from two to ve although it will be appreciated that in larger machines more vanes may be required.

The vanes lie within a conical fmstum the diameter of the upper end of which is about 11/2 times the diameter of the upper end or the core. The base diameter of the frustum outlining the blades may be about four times the diameter of the upper end but the rounding of the blades at their lower ends reduces the diameter of their lowermost tips to about three times the upper end diameter. The agitator may be contained within a cylindrical bowl the diameter of which is about twice the diameter of the lowermost blade tips, that is about nine times the diameter of the top of the core. The height of the agitator is equal to the intended depth of washing liquor in the bowl and is usually of the same order as the maximum diameter oi the agitator. The bowl is usually cylindrical with a substantially flat bottom and a radius joining the wall and bottom. Alternatively bowls of shapes other than cylindrical may be used, for example substantially square bowls.

ln order that the invention may be clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:

FIG. l is a section through a washing machine according to the invention,

FiG. 2 is a plan view of an agitator similar to that shown in the machine of FIG. l,

FIG. 3 is a scrap section on a plane normal to the axis of oscillation of a part of the agitator showing the disposition of one of the vanes, and,

FIG. 4 is a scrap section similar to FIG. 3 showing an alternative disposition of one of the vanes.

The agitator comprises a core made up of a short upper cylindrical portion 21, a conical portion 22 and a flared out dish shaped lower end 23. The core is hollow and the interior may be splined or furnished with suitable formations to engage with complementary formations upon rotor 24 of a suitable driving unit of a Well known kind (not shown).

Three identical, agitator vanes 25 are formed integrally with the core each following a steep truly helical path about the core. Thus each of the vanes is so disposed that it will intersect any cylinder coaxial with the core in a true constant pitch helix. The free edges of the varies fall within a conical frustum. The upper ends 26 are curved to meet the core, the centre third 27 is slightly cut back from the conical frustum and the lower ends 28 are cut away and curved to meet the core. The free edges 29 of the vanes are radiused (FIG. 3) and the vanes taper, for example from a thickness of about lf" at their edges to f/ adjacent the core, and meet the core in a small radius curve.

As shown in FIG. 3 the blades do not extend radially from the core in section normal to the axis of oscillation but are disposed at an angle, the angle of lead 31, to the radius. The axis 32 of the blades in such transverse section may best be considered as extending tangentially to an imaginary circle 33 the centre of which is coincident with the axis 34 of the core. Then the angle of lead 31 is the angle between the axis 32 md the radius 30 passing through the intersection of the blade and core. This angle 31 will increase as the radius of the core decreases. Thus in a typical agitator according to the invention the core radius, the vane radius and the angle 31 may vary as indicated in the following table, the ordinates 1 to 14 being based on equispaced intervals from a polnt ad1acent the top of the agitator to a pomt adjacent the bottom thereof.

Core Core Vane Vane Angle Vertical radius radius radius radius of Lead Ordinates (inches) (centi- (inches) (cms.) 31

Rc metres) v Rv degrees 1 2. 54 1. 512 3. S3 (i0 1 2. 54 1. 854 4. 69 60 1. 090 2. 76 2. 201 5. 59 52. 75 1. 220 3. 09 2. 540 (i. 44 45. .f 1. 356 3. 43 2. 859 7. 27 39. 75 l. 483 3. 76 3. 070 7. 79 35. 5 l. 612 4. 08 3. 312 8. 4() 32. 25 1. 755 4. 45 3. 593 9. 1l 29. 4 1. 890 4. 79 4. 000 10. 16 27. 1 2. 023 5` 0G 4. 546 1l. 52 25. l 2. 5. 49 5. 320 13. 49 23. 4 2. 521 6. 39 5. 64 14. 28 20. 0 2. 838 7. 18 5. 62 14. 23 17. 75 3. 310 8. 40 5. 48 13. 84 l5. 1 3. 637 9. 3l 5. 305 13. 42 13. 75 4. 075 10. 33 5. 07 12.81 12. 5 4. 620 1l. 67 4. 770 12. 07 10. 8 5. 250 13. 2O

FIG. 4 shows a vane 42 in section on a plane normal to the axis of oscillation 43. The centre line 44 of the vane lines upon a generatrix 45 of constant form in relation to the axis 43 and the line 46 joining the blade tip 47 to its intersection with the core 4S has an angle of lead 49 to the radius 50 through the intersection.

The agitator is disposed axially within a cylindrical bowl the walls 35 of which meet the bottom 36 in a curve 37. The bowl is of such a depth that the normal water level 3S corresponds with the cylindrical upper portion 21 of the agitator and the diameter of the bowl is preferably slightly greater than its depth, for example the diameter may be one and one half times the depth.

The diameter of the bowl may conveniently be about nine times the diameter 39 of the cylindrical upper portion 21 of the core and twice the diameter 41 where the bottom ends of the vanes meet the core. The minimum diameter of the frustum defining the free edges of the blades may be about one and a half times the diameter 39 whilst the maximum diameter of the frustum may be about six times the diameter 39, that is about ltwo thirds the diameter of the bowl.

In practice it is desirable that the pitch of the helix on the imaginary cylinder should be about 2.4 to 2.6 times the height of the agitator which gives a blade helical lead of about 350/2.5=144. For maximum eiciency the agitator should oscillate through an angle between 1.3 and 1,55 times the blade helical lead, that is through an angle of 187 to 230. Generally the more rapid the movement of the agitator the more eiticient the washing action obtained. Rapid movement however requires a more powerful drive and in practice the power which can conveniently be used sets the limit. It has been found however that the oscillatory peripheral speed is more important than the oscillatory frequency and the optimum average oscillatory peripheral speed of the imaginary cylinder should be between 8.8 and 10.7 inches (22.3 cms. and 27.1 cms.) per second.

In a machine of average size the depth of washing liquor may be twelve inches (30.5 cms), the bowl diameter may be eighteen inches (45.5 cms.) and the other parts may be in proportion. The volume of the core will then be about 160 cu. ins. (2610 ccs.) and the volume swept by the three vanes about 440 c. ins. (7200 ccs.). Such a machine will accept a load of 9 lbs. (4.06 kgs.) (dry weight) of clothes. This represents 1 lb. (0.45 kgs.) per 330 cubic inches (5400 ccs.) of wash liquor. In a machine of this size a frequency of about 70 to 85 cycles per minute can be achieved with a rotor power such as is acceptable and convenient in a domestic machine.

We claim:

1. A washing machine comprising a bowl and an oscillating agitator disposed upright substantially in the centre of the bowl, the agitator comprising a central core tapering from a base towards the upper end, and at least two vanes mounted at a steep true helical position on the core and having a constant generatrix of constant form in relation to the axis of oscillation disposed so that in section on planes normal to the axis of oscillation a line joining the tip of the vane to its intersection with the core has an angle of lead to the radius through the intersection with the core which is in the direction of the hand of the helix and the vanes having a width that the outer edges thereof lie substantially on a conical trustum rounded oi at the lower ends.

2. A washing machine according to claim 1 in which the vanes in section on planes normal to the axis of oscillation are curved so that the angle of lead increases towards the tip.

3. A washing machine comprising a bowl and an oscillating agitator disposed upright substantially in the centre of the bowl, the agitator comprising a central core tapering from the base towards the upper end, and at least two vanes mounted at a steep true helical position on the core and being disposed so that in section on planes normal to the axis of oscillation they extend tangentially to an imaginary cylinder coaxial with the axis of oscillation, and the angle of lead to the radius being in the direction of the hand of the helix and the vanes having a width that the outer edges lie substantially on a conical frustum rounded oft at the lower ends.

4. A washing machine according to claim 3 in which the outer edges of the vanes lie upon a conical frustum.

5. A washing machine according to claim 3 in which the angle of lead increases from about 10 at the base to about 60 at the top.

6. A washing machine according to claim 1 in which the core is of substantially frusto-conical shape with a short cylindrical part at the top, and the core has a base diameter about four times the top diameter with the lower part of a side being concave and the upper part being straight.

7. A washing machine according to claim 3 in which the lower ends of the vanes curve inwardly to meet the core.

8. A washing machine according to claim 3 in which the diameter of the core at the intersection with the lower ends of the vanes is about three times the minimum diameter of the frustum delining the blades.

9*. A washing machine according to claim 3 in which the conical frustum defining the blades has a minimum diameter about one and a half times the diameter of the top of the core and a maximum diameter about four times the minimum with the bowl being cylindrically shaped and having a diameter about nine times the diameter of the top of the core.

10. A washing machine according to claim 3 in which the helical pitch of the vanes about the core is about 2.4 to 2.6 times the height of the agitator with the blade helical lead being about 144.

l1. A washing machine according to claim 3 in which the agitator oscillates through an angle of about 1.3 to 1.55 times the blade helical lead through an angle between 187 and 230.

12. A washing machine according to claim 1 in which the agitator oscillates at a frequency of to 85 cycles per minute'.

13. A washing machine according to claim 3 in which the oscillatory peripheral speed of the imaginary cylinder is between 8.8 and 10.7 inches per second.

References Cited in the ile of this patent UNITED STATES PATENTS 1,923,580 Nelson Aug. 22, 1933 2,383,783 Dunham Aug. 28, 1945 2,734,367 Geldhof Feb. 14, 1956 FOREIGN PATENTS 824,333 Germany Dec. 10, 1951

Claims

1. A WASHING MACHINE COMPRISING A BOWL AND AN OSCILLATING AGITATOR DISPOSED UPRIGHT SUBSTANTIALLY IN THE CENTRE OF THE BOWL, THE AGITATOR COMPRISING A CENTRAL CORE TAPERING FROM A BASE TOWARDS THE UPPER END, AND AT LEAST TWO VANES MOUNTED AT A STEEP TRUE HELICAL POSITION ON THE CORE AND HAVING A CONSTANT GENERATRIX OF CONSTANT FORM IN RELATION TO THE AXIS OF OSCILLATION DISPOSED SO THAT IN SECTION ON PLANES NORMAL TO THE AXIS OF OSCILLATION A LINE JOINING THE TIP OF THE VANE TO ITS INTERSECTION WITH THE CORE HAS AN ANGLE OF LEAD TO THE RADIUS THROUGH THE INTERSECTION WITH THE CORE WHICH IS IN THE DIRECTION OF THE HAND OF THE HELIX AND THE VANES HAVING A WIDTH THAT THE OUTER EDGES THEREOF LIE SUBSTANTIALLY ON A CONICAL FRUSTUM ROUNDED OFF AT THE LOWER ENDS.