US 3704550 A
Tension springs for counterbalancing a swing-down dishwasher door are nested in outwardly-open, channel-shape support legs for the dishwasher tub, and pivotal connector means which slide along the legs connect the upper ends of the springs to the ends of the lever arms of the dishwasher door bracket so that the springs will be elongated only along their axes and the connectors will pivot to accommodate the varying perpendicular distances between each spring axis and points on the path of movement of the end portion of the lever arm when the door is moved between its opposite positions.
Claims available in
Description (OCR text may contain errors)
United States Patent Hancock [151 3,704,550 1 Dec. 5, 1972 [S4] DISHWASHER DOOR COUNTERBALANCE ARRANGEMENT  Inventor: Charlie L. Hancock, Grove City,
 Assignee: Westinghouse Electric Corporation,
 Filed: May 11, 1971 211 Appl. No.: 142,307
 US. Cl ..49/386, 126/191  Int. Cl. ..E05f l/10  Field of Search ..l26/191, 194; 49/386  References Cited UNITED STATES PATENTS 2,837,080 6/1958 Reeves ..l26/191 3,040,731 6/1962 Mudd ..l26/191 Primary Examiner-Kenneth Downey Attorney-F. H. Henson and E. C. Arenz [5 7] ABSTRACT Tension springs for counterbalancing a swing-down dishwasher door are nested in outwardly-open, channel-shape support legs for the dishwasher tub, and pivotal connector means which slide along the legs connect the upper ends of the springs to the ends of the lever arms of the dishwasher door bracket so that the springs will be elongated only along their axes and the connectors will pivot to accommodate the varying perpendicular distances between each spring axis and points on the path of movement of the end portion of the lever arm when the door is moved between its opposite positions.
10 Claims, 4 Drawing Figures PATENTED DEC 5 I97? 3. 704 550 BACKGROUND THE INVENTION Field of the Invention This invention pertains to the art of counterbalancing appliance doors of the swing-down type.
So far as I know, most front opening dishwashers having swing-down type doors hinged along their lower edges have had their springs attached in such manner that as the door is moved between opposite positions,
the axis of the spring is at least angularly displaced, and
sometimes is shifted in translating fashion. One example of such an arrangement is US. Pat. No. 3,453,779. While one commercially produced dishwasher does have a spring arrangement in which the lower end of the spring is fastened to the lower portion of a support leg and occupies a generally vertical disposition, in that arrangement, the upper end of the spring follows the arc of movement of the lever arm end so that the axis of the spring is angularly displaced as the door is moved between its opposite positions.
My improved arrangement is intended to provide an arrangement in which the spring is confined to movement along its axis so thatthe space occupied by the counterbalancing arrangement is reduced from other arrangements known to me, and in which an adequately balanced condition exists throughout the range of movement of the door.
SUMMARY OF THE INVENTION In accordance with my invention, the lever arms which are attached to each side of the door are dimensioned and located so that their end portions move through an arc sufficiently close to the axis of a channel-shaped support leg that the tension spring may be nested in the channel, and a pivotal connecting means, which also partly nests in the channel, connects the upper end of the spring to the end portion of the lever arm and pivots to accommodate the changing distance between the axis of the spring and points on the are through which the end portion of the lever arm moves. Thus, the spring is confined in its movement to stretching and relaxing along its initial vertical axis so that encroachment upon other useful space about the dishwasher tub is eliminated.
The pivotal connecting means takes the form of a block which slides along the channel-shaped leg. All the coils of the tension spring are spaced from the leg structure to avoid contact therewith and resultant noise, and with the friction between the slidable block and the leg structure providing a braking effect throughout portions of the movement of the block.
DRAWING DESCRIPTION FIG. 1 is an exploded, isometric view of a fragmentary portion of the dishwasher tub and door inner panel, and the counterbalancing arrangement before assembly;
FIG. 2 is a side view of the pivotal connecting block for connecting the door lever arm to the upper end of the tension spring;
FIG. 3 is a sectional view corresponding to one taken along the line Ill-III of FIG. 2; and
FIG. 4 is a fragmentary side view of the counterbalancing arrangement in assembled form with the arrangement as shown in full lines corresponding to the door being closed, and in broken lines with the door being in its normally open horizontal position.
DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, only the right-hand portion of the dishwasher tub 10, door inner panel 12 and counterbalance arrangement are illustrated since the leftahand portions of these parts are, for purposes of the invention, mirror images of that shown in FIG. 1. The tub 10 is supported on each side by two support legs 14 and 16, both of which are channel-shaped in horizontal cross section, with the open parts of the channels facing outwardly. On each side of the tub, at the lower front comers, a hinge support bracket 18 is welded to the tub. Each bracket includes upper and lower forwardly-projecting tongues 20 and 22, respectively, the upper tongue 20 including a hook-shaped end which provides a seat 24 which, .when the inner door panel 12 is assembled to the tub, receives a hinge pin 26 carried by the door bracket 28.
The door bracket 28 (FIG. 1) includes a base part 30 which is welded to the lower comer front face of the door panel and a right angle lever arm portion 32 which, when the door is assembled to the tub with the hinge pin 26 in the seat 24, lies in a plane parallel to the side wall of the tub and spaced slightly outwardly from the support leg 14. The unattached end portion 34 of the lever arm is formed with an upwardly-open hook which is adapted to pivotally connect with the upper end of the pivotal connector block generally designated 36.
-A tension spring 38 (FIGS. 1 and 4) is provided at each side of the dishwasher and is initially assembled in the arrangement by having its lower end hooked into an upwardly embossed portion 40 of the base of the leg. The embossment has an aperture therein to receive the lower end of the spring. The upper end of the spring is attached to the lower part of the connector block 36. This holds the door in place.
Referring now to FIGS. 2 and 3, the pivotal connector member 36 is molded from a material having frictional characteristic such as nylon and basically includes a slide portion 42 adapted to be received in the channel of the support leg 14, and a connector portion 44 which serves to provide the connection between the lever arm 28 and the tension spring 38. The slide portion 42 is generally cylindrical throughout most of its extent with a diameter that adapts it for a free fit within the channel. The connector portion comprises a pair of spaced apart walls 46 and 48 joined at the top by an intermediate circular pin 50 which seats in the hook end (FIG. 1) of the lever arm, a lower circular pin 52 centered with respect to the center of the slide portion 42 and adapted to have the upper end of the spring 38 hooked thereto, and an intermediate triangular shaped web 54 which serves to strengthen the connection between the two walls. A metallic insert 56 is positioned in a bore in the upper pin 50 to provide additional strength at that location.
Referring now to FIG. 4, the relationship of the parts in assembled form is there illustrated. The solid line view corresponds to the door being in a closed, vertical position, while the broken line representation of the parts corresponds to the door being in its horizontal, open position. The open position is limited by the edge 57 of arm 28 engaging tab 59 of bracket 18.
As noted before, the slide portion '42 has a diameter that permits it to rotate freely in the channel of the support leg 14. The lever arm 32 is dimensioned and located, relative to the location of the support leg 14, that the are 58 through which the center of the connection at the end portion 34 moves generally follows the orientation 'of the support leg 14. Thus, while the are obviously cannot parallel a straight line, the centered axis of the support leg 14 does trace a chord intersecting the are 58 at, or adjacent, the end points of the arc..
It will also be noted that the end points of the arc, corresponding to the door being in a horizontal open position, and an opposite vertical closed position, fall within the span of the web of the leg 14. This preferred arrangement limits the degree to which the slider portion 42 is pressed against either of the legs forming the channel of the support leg 14.
As the door is moved from its closed position in which the lever arm 32 extends diagonally downwardly asshown in FIG. 4), the pivotal connector member 36 will pivot within the channel as the axis of the upper pin 50 of the connector follows the arc 58. Thus when the door is, say, half way open, the connector will be pointing diagonally upwardly to the right; and when the door is fully opened, the connector is as illustrated in the broken line position in which it is pointed substantially directly upwardly. Throughout this movement, the axis of the spring 38 is neither angularly displaced nor translated throughout the stretching and relaxing of th spring.
During movement of the connector 36 (FIG. 4) from the solid line to'the broken line position, as the center line of the connector pin 50 moves to the right of the centered axisof the support leg 14, the slider portion 42 will tend to bear frictionally against the right side leg of the channel to a degree that depends upon the perpendicular distance and the centered axis of the support leg 14 (which in the arrangement shown is also the spring axis) and any given point on the arc 58. This frictional engagement between the nylon block and the support leg is considered desirable in that it yields a feeling of smooth operation to the person moving the door and effects a degree of braking. It will also be appreciated that in the solid line position of the connector, the slider block 42 bears slightly against the lefthand leg of the channel since the center of the pin 50 is to the left of the-centered axis of the support leg.
The spring 38 has a diameter and is located to be spaced from both legs and the web of the channel support leg 14 throughout its movement, even though it is nested at least in part in the channel. This prevents any possibility of rubbing of the spring coils against any part of the support leg.
} 1. In a dishwasher including a forwardly-open-face tub and a door for closing said tub face and hinged adjacent its lower edge, a counterbalancing arrangement for at least one side of said door, comprising:
a lever arm fixed to said door at a side thereof adjacent the lower portion and having an end portion movable through an arc in accordance with door movement;
a tension spring for counterbalancing said door at a side of said tub, said spring having a fixed lower end;
means for guiding the upper end of said spring for movement along an axis substantially coincidence with the axis of said spring; and
pivotal means having a lower end portion connected to said upper end of said spring, and having an upper end portion connected to said lever arm end portion so that said pivotal means pivots at both connections to accommodate the varying perpendicular distance between said axis and points along said are. I e
2. In a dishwasher according to claim 1:
said guiding means includes achannel-shaped support leg for said tub, with said channel being outwardly open.
3. In a dishwasher according to claim 2:
said are has end points, corresponding to opposite positions of said door, facing an 'area spanned by the width of the channel of said support leg.
4. In a dishwasher according to claim 2:
said spring is nested in part at least in said channel of said support leg.
5. In a dishwasher including a forwardly-open face tub and a door for closing said tub face, said door having a hinge axis adjacent its lower edge, a counterbalance arrangement for at least one side of said door, comprising:
a vertically-disposed leg adjacent the tub front and extending upwardly along a side of said tub;
a lever arm fixed to the side of said door, said arm being dimensioned and located that its end portion remote from the door moves through an arc, as said door is moved between its opposite positions, generally following said leg;
a tension spring having its lower end fixed adjacent the lower portion of said leg;
pivotal connector means having one portion slidable along said leg and having the upper end of said spring pivotally connected thereto, and having another portion pivotally'connected to said end portion of said lever arm and pivotal about the connection between said one portion and said spring so that said spring is stretched and relaxed along its axis without angular displacement therefrom as said end portion of said lever arm is moved throughout its said arc, said pivotal connector pivoting about both of its said connections to accommodate the varying perpendicular distance between said axis and points along said arc.
6. In a dishwasher according to claim 5:
said leg is an outwardly-open, channel-shaped member in horizontal cross-section; and
said one portion of said pivotal connector means is received at least partly in said channel.
7. In a dishwasher having a forwardly-open face tub and a door having a lower edge hinge axis for closing said tub, a counterbalance arrangement comprising:
a lever arm fixed to each of the opposite sides of said door, each arm having an end portion remote from said door;
a tension spring at each of the corresponding opposite sides of said tub for counterbalancing said door;
a vertically-disposed support leg at each side of said tub adjacent the front thereof;
means fastening the lower end of said spring to the lower portion of said leg;
pivotal connector means for connecting the upper end of said spring to said end portion of said lever arm at two pivotal connection locations, said connector means including a slider portion confined by said leg to movement along an axis coincident with the axis of said spring, said connector means including another portion pivotally connected to said lever arm end portion to provide one of said pivotal connection locations, and pivotal about the axis of connection of the upper end of said spring to said connector means to provide the other of said pivotal connection locations, both said pivotal connections pivoting during door movement to acanzn commodate the perpendicular distance between the axis of said spring and various points along the arc of movement of said end portion as said door is moved.
8. In a dishwasher according to claim 7:
said support leg comprises an outwardly-open channel, said slider portion being received in said channel.
9. In a dishwasher according to claim 8:
said spring is in generally nested relation in said channel, but spaced from the walls forming said channel to avoid contact therebetween during stretching and relaxing said spring.
10. In a dishwasher according to claim 8:
the end points of the arc of movement of said lever arm end portion, corresponding to said door being closed and alternatively open, lie between planes coincident with the opposite legs forming said channel.