US 2642996 A
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June 23, 1953 R. c. OELER EI'AL 2,642,996
WASHING MACHINE CENTRIF'UGAL EXTRACTOR SUPPORT AND DAIIPING MECHANISM Filed llay 1, 1946 3 Sheets-Sheet 1 [N V EN TORS RICHARD 6. OELER ARThURRGONSMNT/NE ATTORNEY R. C. OELER El AL June 23, 1953 2,642,996
WASHING MACHINE CENTRIFUGAL EXTRACTOR AND DAMPING MECHANISM SUPPORT 3 Sheets-Sheet 2 Fi1 ed lay 1, 1946' INVENTORS RICHARDOOELER ARTHUR/R50 STZUVT/IVE 8V ATTORNE June 23, 1953 R. c. OELER ETAL 2,642,996
WASHING MACHINE CENTRIFUGAL EXTRACTOR SUPPORT AND DAMPING wscmmsu 5 Sheets-Sheet 5 Filed May 1, 1946 \\N\\\\\ 21 A E1 IN VHV TORS WGME? Patented June 23, 1953 WASHIN G MACHINE CENTRIFUGAL EX- TRACTOR SUPPORT AND DAMlPING MECHANISM Richard C. Oeler and Arthur R. Constantine,
South Bend, Ind, assignors, by mesne assignments, to Avoo Manufacturing Corporation, New York, N. Y., a corporation of Delaware Application May 1, 1946, Serial .No. 666,420
4 Claims. (Cl. 21063) This invention relates to washing apparatus of the type having a combined Washing and centrifugal extracting mechanism.
Washing machines of the combined washing and centrifugal extracting type present a problem in balance. Some types of these machines use a rotatable clothes cylinder mounted for rotation on a horizontal axis, the clothes being in-,- serted in' the cylinder and rotated at a relatively slow speed in the presence of a washing liquid for the purpose of washing the clothes. Subsequently, in the cycle of operation the Water is drained from the clothes cylinder or surrounding tub and the Washing liquid and the rinse water is extracted from the clothes by increasing the speed of rotation of the cylinder to an amount such that the centrifugal force generated by the increased rotation will cause the water contained in the clothes to be thrown out from the cylinder through perforations or other openings in the circumference. Some types of horizontal axis machines have provided special speed ranges which provide for distribution of the clothes load around the circumference of the cylinder either during the acceleration from washing speed to extracting speed or prior thereto. One type of machine of this character is described in U. S. Patent Re. 22,375. However, even with the special arrangement for distribution to equalize the clothes load to prepare for centrifugal extracting there is nevertheless remaining in all types of these machines a certain amount of unbalance because of imperfect distribution of the clothes weight around the center of rotation of the cylinder. Such unbalance provides a necessity for either securing the machine to the floor or to otherwise provide resilient support properly clamped to assure that the machine will not generate and transmit excessive vibrations and forces to the support or floor.
It is a primary object of the invention to provide a construction for a combined washing and centrifugal extracting machine of the type employing a rotatable clothes cylinder mounted for rotation on an axis inclined substantially from the vertical and to so construct this machine that it will not be necessary to secure it to the floor.
It is a further object to provide a combined washing and extracting machine which may be operated at high rotative speeds for extraction without excessive vibration and may be accelerated from washing speed to extracting speed without transmitting excessive forces to the supporting structure or the floor on which the machine is supported.
It is another object to resiliently support a clothes cylinder of the horizontal axis type in such manner that major damping forces are necessary only in the plane of rotation, thus requiring special damping mechanism only in such plane with minor damping elements in other planes.
The above and other objects of the invention will appear more fully from the following more detailed description and by reference to the accompanying drawings forming a part hereof and wherein:
Figure 1 is a rear view of the machine showing general arrangement of the parts with the back cover of the machine removed.
Figure 2 is a side View partly in section showing the relationship of the parts of the same machine as shown in Figure 1.
Figure 3 is a partially diagrammatic view showing the arrangement of the several parts including spring mounting, weights, and shock absorbers, the view corresponding to the rear view of Figure 1.
Figure 4 is a side view of the diagrammatic assembly of parts shown in Figure 3.
Figure 5 is a cross section through one type of shock absorber used.
Figured is a cross section through a modified form of shock absorber.
Referring to the drawings a substantially square frame In is built up on a base II the vertical corner members l2 extending upwardly at each corner of the frame and these vertical members are secured together at the to by suitable cross members for completing the rectangular frame I 0. Suitable panels may be added to cover the frame H] as shown in the drawings although such panels only serve to give minor support to the frame and form a cabinet for the washing machine. Referring to Figures 1 and 2 the frame Ill supports four springs indicated in the drawings by the numerals I6, IT, IS and I9, these springs are secured to the frame ll! substantially at the corners of the rectangular top portion of the frame. A tub Z0 is suspended on the springs I6, I I, I8 and i 9 inside the frame and cabinet, which suspension is eflected by connections 21, 21A, 28 and 28A between the ends of the springs l6, l1, l8, l9 and the tub 20. The connections are hooks formed in the plates which are Welded to the tub 20 as shown. These connections are so positioned relative to the tub support for the springs 16, ll, l8 and I9 that the springs are inclined from the vertical toward each other and toward the tub as shown in Figure 1.
The amount of this inclination of springs l6, l8 and springs l1, IS in the plane perpendicular to the axis of rotation as shown in Figures 1 and 3 is 9 degrees. The spring pairs l6, l1 and I8, I9 are also inclined in side View as seen in Figures 2 and 4. and the amount of this inclination from the vertical is 3 degrees.
The inclination of the four springs in the relative amounts shown in the planes perpendicular and parallel to the rotation axis, as will be more fully explained hereinafter, is provided for the purpose of more nearly equalizing the natural frequencies of vibration of the suspended unit in the horizontal direction perpendicular and parallel to the axis of rotation with the natural frequency of the suspended unit ina vertical direction.
The suspension above described supports the tub 26 from the top of frame 10 on the four inclined springs l5, l1, l8 and [9. The tub is the outer cylindrical tub of a horizontal aXis type washing machine of the general type shown in U. S. Patent Re. 22,375. The major parts are the tub 26, an inner rotatable clothes containing cylinder 21 which is supported for rotation at one end on shaft 22. The shaft is driven for rotation from the back of the tub through pulley 23 and belt 24 from a motor 25 with suitable transmission 25 for two speeds, a washing speed and a higher rotative speed for centrifugal extraction. The clothes to be washed are D1115 into the front of the tub through a suitable central door substantially symmetrically positioned in front of the open end of the cylinder and on the axis of cylinder rotation and washing liquid is made available in the tub and drained therefrom by suitable connections and controls described in the aforementioned U. S. Patent Re. 22,375 but not herein described in detail.
In the machine herein disclosed the motor 25 is supported on the tub 2D and therefore the driving unit made up of the aforementioned parts 2!, 22, 23, 25 and 26 together with all parts normally mounted on tub 20 make up a unit supported by the spring assembly IS, ll, [8, l9.
The center of rotation for clothes containing cylinder H is the axis of shaft 22 and it is desirable that the center of the suspended weight in a vertical plane perpendicular to the axis of rotation, as viewed in Figures 1 and 3, substantially coincide with the center or axis of rotation. Inasmuch as the motor and transmission and other added weights are located on the bottom of the tub 29 it becomes necessary to balance these weights by addition of weights at the top of the tub 20. Accurate computations are made, considering component weight and location of the several parts and the added weights and 35 added to bring the center of weight of the suspended unit substantially coincident'with the axis of rotation. The amount of added weight for the machine illustrated was approximately 89 pounds.
Considering the relative location of weights and springs in side view, the added weights 35 and 36 are so located from front to back that the center of weight substantially coincides with the probable center of weight, front to back, of the clothes load which is subject to unbalance. A clothes load is shown distributed around the inner wall of the cylinder 2| in Figures 3 and 4. The springs i6, I8 and IT, IS front and back are then spaced substantially symmetrically around this center. The center of clothes load and center of weight are, according to the above specified requirements, located substantially on the line XX in Figures 2 and 4 and if a condition of perfect balance of the clothes load could be obtained then these weight centers would also lie on the axis of rotation A--A also shown in Figures 2 and 4. It is apparent that deviations from perfect balance in clothes loading will cause variation of the center of weight along the line XX but only very slight deviations are to be expected along line AA due to the relatively minor shifts in clothes load in the front to back direction. Furthermore with the above selection of weight distribution and spring, location the center of weight for substantially all conditions of clothes load is very close to a symmetrical location between the front and rear springs.
Two shock absorbers 3i) and 3| each made up of piston member 32 and cylinder member 33 are connected between the frame It! and the lower portion of the tub 20. The longitudinal axis of these shock absorbers is so positioned as to extend in the direction of the axis of rotation which also coincides, it will be remembered, with the center of weight. The piston member ends 32 are shown connected to the tub 20 and the cylinder member ends connected to the frame l0. Resilient connections are preferable as shown.
The shock absorbers are so located, front to back, as shown in Figure 4 that their line of action is in the plane of the line X-X previously mentioned, that is in a plane which passes through the center of weight of both the structural parts of the machine suspended on the springs and the probable weight center of the clothes load. By thus positioning the line of action of the shock absorbers substantially coincident with the probable center of unbalance clothes load, the couple effect due to variations of clothes load locations is minimized to the extent that a major damping force is not required in any plane other than in the selected plane perpendicular to the axis of rotation. ters, spring locations and shock absorbers as herein specified, the weight variation front to back of the clothes load is not sufficient to introduce any substantial couple which would set up forces due to vibration which would require a special damping means. the machine thus constructed is therefore substantially simplified because of the fact that special damping elements such as the shock absorbers shown are necessary only in one plane, namely the selected plane perpendicular to the axis of rotation.
The shock absorbers 30 and 3| are preferably of the hydraulic type such as shown in cross section in Figure 5. The shock absorber shown in Figure 5 is of the so-called direct acting type, more specifically described in U. S. Patent Number 2,078,364. A ported piston 50 secured to a piston member 5| is mounted to travel in a cylinder 52 and such movement causes fluid carried in the cylinder to be forced through the ports in piston 50 and also through ports in a valve member 53. The ports in piston 50 and valve member 53 are each provided with a pressure relief valve 54, 55 set to open at a fixed value so that movement of piston 50 in either direction causes resistance to movement to be built up to a definite value after which such resistance remains substantially constant because of the opening of the relief valve.
The effect of the shock absorbers is to impose a resistance which builds up to a definite value and opposes the movement of the tub in a plane per- In other words, with the weight cen- The problem of damping with pendicular to the axis of rotation or as it might be termed, in theplane of rotation. The line of action of such resistance could also be described as acting in a plane which passes through the center of weight, front to back, of the machine and the supporting unit.
The machine so far described comprises a unit in which a rotatable clothes cylinder is mounted and such unit is suspended from four spring members previously described as l6, l1, I8 and I9. It is possible to select springs of such properties that a definite natural frequency of vertical vibration of this suspended unit will be had.
For the maximum degree of isolation of the forces normally transmitted to the frame it is desirable to provide a natural frequency for the supported weight in the vertical direction of a value substantially lower than the frequency of the forces set up by the unbalanced clothes load (that is, the speed of extraction) and it is also to be desired that such frequency be as low as practicable.
If a unit is suspended with certain inclination of the spring pairs toward each other as previously mentioned it will also affect the natural frequency of vibration in each of the horizontal directions. Witha spirng unit selected for a vertical frequency of 108 cycles per minute and with an inclination of the front springs toward each other of 9 degrees and an inclination of 3 degrees between the springs from front to back as previously described the suspension having a total weight of 244 pounds and a spring deflection of three inches provides a natural frequency of 88 cycles perminute in a horizontal direction and 80 cycles per minute in the front to back direction. It is therefore determined that the relative inclination of the springs is so selected that the lowest natural frequency will be from front to back, the higher natural frequency will be vertical and the natural frequency value for horizontal direction in front view will be between these values and such relationship is determined by the relative inclination of the spring members. It is further noted that the natural frequency values are not widely spaced, all occurring between 80 cycles per minute and 108 cycles per minute. It is therefore apparent that the critical speed front to back will be 80 R. P. M., the horizontal direction front view will be 88 R. P. M. and the vertical critical speed will be 108 R. P. M.
When a load of clothes is placed in the cylinder and washing operation carried out by continuous rotation at a relatively low speed, say 60 R. P. M. for tumbling the clothes in the presence of a washing solution, the relatively low uniform speed will not set up vibrations which will require special compensation or special mounting to absorb the shock thereof. However, when the speed is increased for the purpose of using the wash cylinder as a centrifugal extractor, the forces produced are substantially greater. With the machine illustrated the acceleration from 60 R. P. M. upward first encounters and passes the natural frequency of 80 cycles per minute in the horizontal direction from front to back of the machine. Inasmuch as the forces generated by the rotating cylinder are not great in that direction no real disturbance occurs and the speed is passed with the forces absorbed mainly by the spring suspension and rubber mounting of the shock absorbers. The next critical speed of 88 cycles per minute in the horizontal direction in the plane of the shock absorbers is resisted by the shock absorber units and sufi'icient movement is allowed to absorb the forces without too great movement of the suspended unit. The major vertical critical speed is next encountered at 108' cycles per minute and 108 R. P. M. and at this speed the amount of damping which the shock absorbers must be designed to provide isdetermined largely by the maximum allowable movement at the critical speed corresponding tothe vertical natural frequency and is also determined by the limitations of cabinet size since necessary clearance between the suspended unit and the cabinet must be maintained. After the critical speed of 108 R. P. M. is passed the unit tends 'to gyrate in such manner as to rotate around its center of mass, the magnitude of this gyration depending upon the amount of out of balance load which is imposed by the clothes load. With the weight distribution as herein specified the shape of the path of gyration is substantially circular.
A modified form of shock absorber is shown in Figure 6. In this shock absorber the relief valve has been omitted from the piston and the pressure relief valve is only available in one direction of movement. Such a construction provides a reduction in cost.
Although the invention has been described by reference to a specific structure found practical in actual operation it is intended that various modifications may be made Within the scope of the following claims.
1. In a washing machine, a frame, a clothes cylinder mounted for rotation about a substantially horizontal axis, a support for said cylinder, mechanism to rotate said cylinder, a tub unit carrying said support for said cylinder and said mechanism to rotate said cylinder, a resilient support for said tub unit comprising a plurality of resilient members each having one end thereof attached to said tub unit and the other end attached to said frame and providing a resilient suspension having a major deflection in a vertical plane and a minor deflection in a horizontal plane, a pair of damping members with longit-udinal axes extending at an angle to each other in a direction substantially toward the center of rotation of said cylinder and each having one end thereof attached to said tub unit and the other end attached to said frame, each of said damping members comprising hydraulic piston means having intersecting lines of force and having relative movement in the direction of the longitudinal axis of said damping member thereby to produce a resistance to movement parallel to each of said longitudinal axes of each of said damping members.
2. In a washing machine, a frame, rotatable cylinder for containing clothes to be washed, a support unit for said rotatable cylinder supporting said cylinder for rotation about an axis substantially inclined from the vertical, drive means for rotating said cylinder carried on said support unit, auxiliary weights also carried on said support unit positioned to balance said support unit, said cylinder and said drive means thereby to locate the center of mass of said unit, said cylinder, said drive means and weights substantially on the axis of rotation of said cylinder, a plurality of resilient members vertically and horizontally suspending said support unit from said frame and providing resilient support against movement in a vertical and horizontal direction, and damping means comprising at least two hydraulic piston means each having one end thereof attached to said support unit and the other end attached to said frame and having relative movements providing damping forces having direction of application intersecting substantially on the axis of rotation of said cylinder, said damping means being angularly inclined towards each other and in a direction substantially toward the axis of rotation of said cylinder.
3. In a clothes washing machine, the combination of a frame, a tub, a rotatable cylinder disposed in the tub, rotating :means carried by the tub for rotating the cylinder about an axis substantially inclined from the vertical for extracting fluid from clothes contained therein, said tub, cylinder and rotating means defining a unitary structure, resilient members oppositely inclined from the vertical for resiliently supporting the unitary structure from said frame and resiliently opposing movement .in a vertical and horizontal direction, and damping means comprising a pair of hydraulic piston means secured between the frame and the tub and having lines of force intersecting substantially at the axis of rotation of said cylinder, said hydraulic piston damping means having their respective longitudinal axes angularly inclined towards each other in a direction substantially toward the axis of rotation of said cylinder.
4. In a machine of the character described designed for washing and centrifugal extraction, a frame, a rotatable cylinder mounted for rotation on a substantially horizontal axis, a support unit for such cylinder, drive means for rotation carried on said support unit, added weights on said support unit of such amount and location as to position-the center of weight longitudinally of the axis'of rotation substantially coincident with the .center of weight of the clothes longitudinally of the said axis of rotation, four resilient members connected for suspending said support unit from said frame, two in-front and two in back and spaced symmetrically about the center of weight, damping members resiliently mounted between the frame and the support unit comprising a pair of hydraulic pistons angularly inclined towards each other and in a direction substantially toward the center of rotation of said cylinder, said damping members having intersecting lines of force producing damping forces in a line :of action in a plane substantially perpendicular tothe axis of rotation of said cylinder and substantially in line with the center of weight'of the clothes .load and in line with the center of Weight of the suspended support unit and the weights carried thereby.
RICHARD C. OELER. ARTHUR R. CONSTANTINE.
References Cited in the file of this patent UNITED STATES PATENTS Number Name 7 Date 2,091,536 Van Impe Aug. 31, 1937 2,291,088 Morgenstern July 28, 1942 2,296,260 Breckenridge Sept. 22, 1942 2,300,421 Henderson Nov. 3, 1942 2,352,362 Bassett,'Jr. June 27, 1944 2,356,319 Bruckman Aug. 29, 1944 2,406,226 Kimball Aug. 20, 1946 2,526,048 Russell Oct. 17, 1950 2,555,269 Chamberlin May 29, 1951