Czech, James I. (Stevensville, MI)
Oakley Jr., Roy C. (Coloma, MI)

05/325983

12/17/1974

01/23/1973

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Whirlpool Corporation (Benton Harbor, MI)

68/23.300

248/621, 68/23.500, 210/364, 267/178

D06F37/24; F16F15/067; D06F37/20; F16F15/06; D06F37/24

68/23.1,23.3,23.5 210/364,144 248/20,21,350,358AA 267/178

Hornsby, Harvey C.

Coe, Philip R.

Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson

Having described the invention, the embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows

1. In a vertical axis automatic washing machine having a cabinet, a cabinet base, and a receptacle assembly within said cabinet, a suspension means for suspending said receptacle assembly above said base, said suspension means comprising:

2. A vertical axis washing machine according to claim 1 wherein said mounting members connecting respective ones of said springs to said receptacle assembly each have the same respective groove length and said one mounting member and said at least one other mounting member connect their respective associated spring members to said base.

3. A vertical axis washing machine according to claim 1 wherein said mounting members connecting respective ones of said springs to said receptacle assembly each have the same respective groove length and said mounting members connecting respective ones of said springs to said base each have a different respective groove length.

4. A vertical axis washing machine according to claim 1 wherein said mounting members connecting respective ones of said springs to said receptacle assembly and said mounting members connecting respective ones of said springs to said base are resilient and have metal inserts for receiving screws thereinto to secure said mounting members, respectively, to said receptacle assembly to said base.

5. In a vertical axis automatic washer having a cabinet, a cabinet base, a receptacle assembly within said cabinet, said receptacle assembly including a tub, a basket within said tub mounted for spinning movement about a center axis, and a drive mechanism for said basket, said receptacle assembly having a center of gravity displaced from said center axis, and a suspension system for suspending said receptacle assembly above said cabinet base, said suspension system comprising:

6. A vertical axis automatic washer according to claim 5 wherein said given spring rate is dependent on the number of free coils of said helical springs and said upper and lower spring mounting means comprise members each having a cylindrically shaped surface provided with helical grooves to receive engagingly a number of coils of said springs and said number of coils received determines said given spring rate of each of said assemblies.

7. A vertical axis automatic washer according to claim 6 wherein said mounting means are resilient.

8. In a vertical axis automatic washer having a cabinet, a cabinet base, a receptacle assembly within said cabinet, said receptacle assembly including a tub, a basket within said tub mounted for spinning movement about a center axis, and a drive mechanism for said basket, said receptacle assembly having a center of gravity displaced from said center axis, and a suspension system for suspending said receptacle assembly above said cabinet base, said suspension assembly comprising:

9. The vertical axis automatic washer of claim 8 wherein said upper and said lower mounting means is adapted to provide at least one of said suspension assemblies with a given spring rate which is different from the given spring rates of the other of said suspension assemblies whereby said suspension system compensates for said center of gravity being so displaced from said center axis to maintain said center axis in a substantially vertical attitude.

10. The vertical axis automatic washer of claim 5 wherein said mounting means are resilient.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to laundry appliances, such as automatic washing, rinsing and drying machines, and more particularly refers to a suspension assembly for supporting a washing receptacle or basket and drive assembly from a cabinet base to isolate the cabinet from vibration caused by the rotation of the basket with an unbalanced wash load.

2. Description of the Prior Art

The elimination of excessive vibrations in automatic washing, rinsing and drying machines for home use has been an area of continuing development. Excessive vibrations usually occur when there is a non-uniform distribution of clothes in the rotating clothes container or basket as the same spins rapidly to centrifuge excess water from the clothes. While a high rate of spin is desirable during the centrifuging operation, the maximum rate of spin is limited by the capabilities of the tub suspension system to isolate the machine cabinet from the vibrations or oscillatory motion caused by the unbalanced load. A complex suspension system may permit a high rate of spin, however, in order to maintain the cost of the laundry appliance within the reach of most consumers, the suspension system should also be compact, inexpensive and easily assembled. The use of extension springs and mechanisms for providing both dampened and free suspension systems during different washing machine operations as described in U.S. Pat. No. 2,296,260 have been utilized. Compression springs, supporting the washing receptacle and drive assembly from below are shown in U.S. Pat. No. 2,665,007 with adjustable spring preload means for maintaining vertical receptacle attitude.

SUMMARY OF THE INVENTION

A washing receptacle suspension system is provided to stabilize the receptacle during a washing operation, prevent excessive vibration transfer to the cabinet during a centrifuging operation, and to maintain a vertical attitude of the washing receptacle in the unloaded condition.

The suspension system has a plurality of essentially identical helical springs vertically oriented with each having a plurality of coils. Upper mounting means are provided for mounting each of the springs to the receptacle at one end and lower mounting means are provided for mounting each of the springs to a base at the other end. The lower mounting means have a surface defining a cylindrically shaped member and have a groove in the surface defining a helix on the cylindrically shaped member of sufficient length to receive at least one of the spring coils. First, second and third lower spring mounts are provided, each having a different length of helix, for receiving a differing number of spring coils.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectioned view of the automatic washer showing the suspension of the invention in the undamped mode;

FIG. 2 is a sectioned view of the automatic washer showing the suspension of the damped mode;

FIG. 3 is a top schematic view of the automatic washer showing the positions of the three suspension elements and the center of gravity of the machine;

FIGS. 4, 5 and 6 are sectional views of the three suspension elements;

FIG. 7 is a side view of the lower spring mount of the suspension element shown in FIG. 4; and

FIG. 8 is a top view of the lower spring mount of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the preferred embodiment, as illustrated in the drawings, the automatic washer 7 has a suspension system comprising three assemblies or elements, 25, 26 and 27. Supported by these three elements is a conventional clothes receptacle assembly 8 including a drive means. The clothes receptacle assembly comprises a base plate 20, attached to the top of which is a tub 12 with a rotatable basket 13 mounted inside for receiving clothes to be washed. An agitator 14 is provided inside the basket 13 to agitate a clothes load during the washing cycle. The drive means for the agitator 14 and basket 13 is provided by a motor 15 and a transmission 16. Water enters the tub 12 through a solenoid operated valve 3 and water inlet 4 from an appropriate source (not shown). A pump 28 is provided to pump the washing liquid from the tub 12 through an appropriate plumbing system (not shown) to a drain (not shown). A conventional timer 17 is provided to control the various cycles of the automatic washer.

As illustrated in FIG. 4 by suspension element 26, an element consists of a spring 30, and upper and lower resilient spring mounts 31 and 32, respectively. The mounts are held in place by respective screws 5 and 6 as shown in FIG. 2. The upper spring mount 31 is attached to a support 22 of base plate 20. The lower spring mount 32 is attached to the cabinet base 18. At the point of attachment of the lower spring mount 32 to the cabinet base, a protrusion 19 is provided to facilitate proper positioning of the mount on the base. This suspension element mounting and construction provides for the unique features of the suspension system of the automatic washer as is hereafter explained.

The washer has conventional cycles of agitation, pump out, and extraction or centrifuging. During operation of the automatic laundry appliance or washing machine 7, the tub 12 is first filled with water or other laundry solution through inlet 4 and the agitator 14 is oscillated via the transmission unit 16 and the motor 15. After completion of that operation, the water is drained from the tub 12 by pump 28 and the basket 13 is thereafter rotated at a high speed to extract or centrifuge the water from the clothes contained in the basket. In the event the clothes are non-uniformly located or distributed within the basket during the extraction operation, the basket, tub, and base will together execute an oscillatory motion, which, if transmitted to the cabinet, may cause an undesirable and excessive vibration. The suspension system of the present invention is designed through the use of springs having a low spring rate (lb. force applied/in. deflection) to isolate the rotating and oscillating parts from the cabinet 10 and cabinet base 18 during the extraction cycle, thereby preventing vibration transfer. Because of the low spring rate of the suspension springs, when the water is added to the tub 12 for the agitation cycle, the weight of the water added causes the receptacle assembly 8 to move down against the upward force of the springs until the upper and lower spring mounts bottom against each other. As illustrated by assembly 26 in FIG. 2, upper spring mount 31 is bottomed against the hollow cylindrical portion 33 of the lower spring mount 32. During the pump out cycle, water is pumped from the tub 12 by the pump 28 to an appropriate drain. The upward force of the springs is then greater than the weight of the receptacle assembly 8 and the assembly moves upward as shown in FIG. 1. In this portion of the pump out cycle and in the extraction cycle, as illustrated by assembly 26, the upper mount 31 and the cylindrical portion 33 of the lower mount 32 are no longer in contact, and the receptacle assembly is suspended only on the springs.

It is therefore contemplated by the present invention to allow the suspension system to provide large damping of the forces created during the agitation cycle and essentially no damping of forces during the spin cycle. These characteristics are desirable because during the washing cycle large forces are created by the oscillatory motion of the agitator against the clothes and water in the tub and a stable tub support is needed to prevent movement of the tub which might cause damage to the cabinet or which might cause the liquid in the tub to splash out the top opening 9 in the tub and run down onto the electrical components such as the motor 15 and cause electrical shorting. The stable base during the agitate cycle is provided in the instant invention by contact of the upper and lower spring mounts when water is added to the tub. However, during the extraction cycle it is best to provide no damping and a suspension with a low spring rate such that if an unbalance occurs in the basket due to an off balance load the forces created by the off balance will be most effectively isolated. This is due to the fact that suspension systems with low damping rates provide for lower transmission of forces above the system critical speed than do systems with large damping. Also, systems with a low spring rate have a lower critical speed so that during acceleration of the basket at the start of the extraction cycle the critical speed is quickly passed through. The low damping and low spring rate of the instant suspension system are provided by the separation of the upper and lower spring mounts when water is drained from the tub. Because of the low spring rates utilized which allow relatively free movement of the receptacle, it is necessary to limit any large excursions of the receptacle as the spinning basket passes through the critical speed in order to prevent damage to the appliance.

The instant suspension system provides for this limitation on large excursions should a large horizontal force be created by an unbalanced load during acceleration of the basket through critical speed during the extraction cycle. The lower spring mount 32 is provided with a hollow cylindrical extension 33. The outer diameter of the extension 33 is smaller than the inner diameter of the spring 30. Therefore, extension 33 does not contact the spring 30 except when a large force tends to move the receptacle assembly horizontally to such an extent that the tub might contact other components inside the cabinet, such as timer 17. As shown in FIGS. 4, 5 and 6, each of the lower spring mounts 32, 42 and 52 have extensions 33, 43 and 53, respectively, to provide for the above mentioned stability.

The suspension element assemblies further provide for a vertical attitude of the receptacle assembly 8 when not loaded with clothes and washing liquid. Because the center of gravity of the receptacle assembly is not in the center of the receptacle assembly, due to the off center placement of motor 15, the suspension assemblies must provide a means of attaining a vertical attitude of the receptacle. With the three suspension elements 25, 26 and 27 equally spaced from the center of the machine and 120° apart, as shown in FIG. 3, it is required that the three suspension elements have differing spring rates in order to maintain the vertical attitude of the tub and agitator when the tub is not loaded with clothes and washing liquid. The three elements 25, 26 and 27, shown in FIGS. 4, 5 and 6, are of differing spring rates to provide for a vertical attitude of the tub assembly so that when the weight of the receptacle assembly is applied, each element will deflect the same amount even though each is supporting a different weight. Each element comprises a spring, an upper resilient spring mount, and a lower resilient spring mount. The three springs 30, 40 and 50 are essentially identical, each having the same free length, diameter of wire and number of coils. Each of the three upper spring mounts 31, 41 and 51 are also essentially identical each being generally cylindrical and having helical grooves 34, 44 and 54 on their cylindrical surface to receive coils of the springs. Each of the grooves 34, 44 and 54 are of the same length so as to receive the same number of coils of the respective springs 30, 40 and 50. Metal inserts 37, 47 and 57 are provided in the respective upper mounts 31, 41 and 51 for attachment of the mounts to supports 22, 21 and 23, respectively.

Each of the lower resilient spring mounts 32, 42 and 52 are cylindrically shaped and have helical grooves 35, 45 and 55, respectively, on their cylindrical surface and extensions 33, 43 and 53 respectively for the purpose previously discussed. Metal inserts 36, 46 and 56 are provided in the lower mounts 35, 45 and 55 respectively to receive bolts or screws to secure the mounts to the cabinet base 18. The spiral grooves provided in the lower spring mounts are of differing lengths to provide for receiving different numbers of coils of the respective springs. As shown in FIG. 4, lower spring mount 32 has a groove 35 of sufficient length to receive approximately 2.5 coils, 30a, 30b and one half of 30c, of spring 30. In FIG. 5, lower spring mount 42 has a groove of sufficient length to receive approximately 3.5 coils, 40a, 40b, 40c and one half of 40d, of spring 40. In FIG. 6, lower spring mount 52 is provided with a spiral groove of sufficient length to receive approximately 4.25 coils, 50a, 50b, 50c, 50d and one quarter of 50e, of spring 50.

Being representative of all the lower spring mounts 32, 42 and 52, mount 32 is shown in FIGS. 7 and 8. The mount is generally cylindrically shaped and has a large diameter lip 38c at the lower end 38a. Hollow cylindrical extension 33 protrudes from the upper end 38b. The cylindrical surface of mount 32 has a helical groove 35 extending from end 38b to end 38a for receiving approximately 2.5 coils of spring 30. At end 38a of the mount a protrusion 39 is provided to form a locating stop for abutting the spring 30 when it is received in the groove.

As previously stated, each of the suspension elements has a different spring rate in order to maintain a vertical attitude of the tub and agitator. The differing spring rates of the elements are realized even though the unassembled springs are essentially the same because the lower spring mounts capture a different number of coils of each spring. This varies the number of free coils of each spring and because the spring constant of a spring is inversely proportional to the number of free coils, the spring constant is different for each of the assemblies shown. Referring to FIGS. 4, 5 and 6, it can be seen that the upper spring mounts 31, 41 and 51 in each of the elements 26, 25 and 27 capture approximately 2.5 of the 14.5 coils of the spring shown. Element 26 has coils 30a through one half of 30p, and upper mount 31 captures coils 30m, 30n and one half of 30p. Element 25 has coils 40a through one half of 40p and upper mount 41 captures coils 40m, 40n and one half of 40p. Element 27 has coils 50a through one half of 50p and upper mount 41 captures coils 50m, 50n and one half of 50p. The lower spring mount in FIG. 4 captures approximately 2.5 coils of the spring leaving 9.5 active spring coils, the upper half of 30c through 30 L, in the element of FIG. 4. The lower spring mount in FIG. 5 captures approximately 3.5 coils of the spring leaving 8.5 active coils, the upper half of 40d through 40L, in the spring of the element of FIG. 5. The lower spring mount in FIG. 6 captures approximately 4.25 coils of the spring leaving 7.75 active coils, the upper three quarters of 50e through 50L, in the spring in the element 27 of FIG. 6. Thus, it can be seen that even though the springs 30, 40 and 50 in the respective elements 26, 25 and 27 are essentially the same the spring constants of the elements differ, element 27 having the highest spring rate, and element 26 having the lowest spring rate.

Although the arrangement shown is preferred, the same results of differing spring constants for the element could be accomplished by varying the length of groove in the upper element instead of the lower element or by a combination of varying groove lengths in upper and lower elements.

Although minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.