US3820866A

US3820866A - Appliance door control mechanism

Info

Publication number: US3820866A
Application number: US00353818A
Authority: US
Inventors: H Kaldenberg
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 1971-07-15
Filing date: 1973-04-23
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28

Abstract

A door control mechanism for an appliance is operable for controlling movement of the door between a substantially horizontal normally open position and an overload position at which a portion of the door engages the floor. The door control mechanism is preloaded to maintain the door in the horizontal position when supporting less than a predetermined loading but will effect movement of the door to the floor responsive to an overloading of the door for preventing tipping of the appliance.

Description

United States Patent 1191 Kaldenberg June 28, 1974 APPLIANCE DOOR CONTROL 3,212,835 10/1965 Beckett et a1 312/319 MECHANISM 3,322,480 5/1967 Barnstead et al. 312/276 3,453,779 7/1969 Reifenber 49/386 [75] Inventor: Henry J. Kaldenberg, Des Moines, g

Iowa Primary Examinerl(enneth Downey v Asslgncei The Maytag p y Newton- Attorney, Agent, or Firm-William G. Landwier; Richlowa ard L. Ward [22] Filed: Apr. 23, 1973 [2|] Appl. No.: 353,818 57 ABSTRACT 63 Related Apphcatlon Data A door control mechanism for an appliance is opera- 1 cofmnflatlon f i 1971* ble for controlllng movement of the door between a 2 g 'g of May substantially horizontal normally open position and an one overload position at which a portion of the door engages the floor. The door control mechanism is pre- 312/276 23 1 loaded to maintain the door in the horizontal position [58] Fieid 076 319 when support1ng less than a predetermined loading but w1l1 effect movement of the door to the floor responsive to an overloading of the door for preventing [56] UNITE D S' F X; ES 1 ZiENTS I tipping of the appliance Panton et a1 312/276 14 Claims, 5 Drawing Figures PATENTEDmza 1914 SHEU 1 BF 3 Hal 2V J. MADE/V5526 minimum mm sainaorg //v VEA/TOR f/EA/PV 1,4444 DEA/5519C;

APPLIANCE DOOR CONTROL MECHANISM CROSS-REFERENCE TO RELATED APPLICATION This is a continuation of application Ser. No. 163,047, filed July 15, 1971 which in turn is a continuation of application Ser. No. 820,735 filed May 1, 1969, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a door control mechanism for an appliance operable for preventing tipping of an appliance when an overload is placed on the open door.

the outwardly extending end of the substantially horizontal door, the appliance could tip over and result in injury to persons close to the appliance and also. result in damage to the appliance. The problem of appliance. upsetting could be overcome, as in prior art, by providing outrigging devices or bracing. Previously used devices, however, represent unattractive and expensive solutions to the problem and thus there remains a need to provide an improved means for preventing the upsetting of an appliance.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide animproved system for preventing the upsetting of an appliance responsive to the overloading of a door in an outwardly extending open position.

It is a further object of the instant invention to provide door control means for an appliance door to control movement ofthe door between a normally open substantially horizontal position and an overload position.

It is a further object of the instant invention to provide an appliance having a hinged door operable to a substantially horizontal open position and having a yieldable connection between the door and the cabinet structure operable for positioning the door for normal use and responsive to an overload condition for releasing the door for movement to the floor.

It is yet a further object of the instant invention to provide means operable in an appliance for locating and yieldingly maintaining a hinged door in a substantially horizontal position and responsive to an overload on the open door for permitting movement of the door to thefloor from the horizontal position. These objects are achieved in an appliance having a doorhinged at the bottom on one side of the cabinet and controlled formovement between a substantially horizontal normally open position and an overload position engaging the floor. The control mechanism cates the door in the normal open position and yieldingly maintains the door in the open position when loaded below'a predetermined load and effects movement of the door to the floor when an excess load is applied to the appliance door.

Operation of the device and further objects and advantages thereof will become evident as the description proceeds proceeds and from an examination of the accompanying three pages of drawings.

DESCRIPTION OF THE DRAWINGS The drawings illustrate preferred embodiments of the invention with similar numerals referring to similar parts throughout the several views, wherein:

FIG. 1 is a fragmentary view of a dishwasher appliance showing the door in the closed position and having portions broken away to show the instant invention;

FIG. 2 shows a fragmentary portion of a dishwasher appliance similar to FIG. 1 and with the door shown in the open substantially horizontal position;

FIG. 3 shows a fragmentary portion of a dishwasher appliance showing the appliance door in the overload. position engaging the floor and showing further details of the operation of the instant invention;

FIG. 4 shows a fragmentary portion of a dishwasher appliance including an alternate embodiment of the instant invention; and, 7

FIG. 5 also shows a fragmentary portion of a dishwasher appliance and illustrates a still further embodiment of the instant invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a fragmentary portion of a dishwashing appliance. A cabinet structure 10 is supportable on a horizontal surface 11 and includes a tub-like member 13 defining a washing chamber, a supporting frame 14 for supportingthe tub member 13 on the horizontal surface 11 through a plurality of casters or rollers 15, a sheet metal wrapper or housing 16 enclosing the tub member 13 and supporting frame 14, and a removable lower front panel 19.

The cabinet structure 10 defines an access opening into the washing chamber on one of the substantially vertical sides of the cabinet structure 10. A door 23 is mounted on the cabinet structure 10 and includes a seal member 24, as best shown in FIGS. 2 and 3, for sealing the access opening upon movement of the door 23 to a substantially closed position as shown in FIG. 1. In this application, the front side of the appliance will be considered that side having the access opening and the door 23.

Means are provided for hinging the door 23 to the cabinet structure 10 through a pair of hingeseach of which includes a hinge bracket 26 fixed to the cabinet structure 10 and a hinge pin 29 in turn fixed to the hinge bracket 26. Fixed to the movable door 23 is a bracket member 30 including a slotted pivot portion 31 engageable with the hinge pin 29 for supporting the lower end of the door-23 on the hinge brackets 26. The bracket member 30 also includes an arcuate arm portion 33 extending through an opening 34 in a flange 35 of the cabinet structure 10 beside the tub member 13. The end of the arcuate arm portion 33 receives one end of a door biasing spring member 39 attached at the other end to the mounting means 14. The spring member 39 partially compensates for the weight of the door 23 in the open position and biases the door 23 to the closed position. The end of the arcuate arm portion 33 also includes a plurality of teeth forming a gear segment 40 operable about the pivot pin 29 and forming a part of a preferred embodiment of the instant invention as will be more fully explained hereinafter.

In accordance with the instant invention, door movement control means 43 are positioned between the juxtaposed walls of the tub member 13 and the enclosure 16 and are cooperable with the gear segment 40 on the arcuate arm portion 33 to control the movement of the appliance door 23.

A gear member 44 is pivotally mounted on the side of the tub member 13 and includes a gear segment 45 operable about the pivot pin 46 supporting the gear member 44. The gear member 44 includes an outwardly extending arm 49 having an offset end portion 50 to which is connected one end of a biasing spring 51 of which the opposite end is connected to a bracket 53 fixed to the wall of the tub member 13. An adjustable stop means 54, including a bracket 55 fixed to the wall of the tub member 13 and a threaded member 56, limits the counterclockwise rotation of the gear member 44 about the pivot pin 46. A preloadforce on the biasing spring 51 maintains the gear member 44 against the adjustable stop 54.

Referring to FIG. 2, it is seen that as the door 23 is moved to an open position with the door extending outwardly from the cabinet in a substantially horizontal direction the arcuate arm member 33 moves about the hinge pin 29 to position the gear segment 40 on the arcuate arm portion 33 for engagement with the gear seg ment 45 of the tub-mounted gear member 44. The first tooth 58 of the gear segment 40 on the door-mounted arcuate arm 33 will in fact engage the first tooth 59 of the tub-mounted gear member 44 to serve as a stop or locater means for the door 23 under the preloading force of the gear member biasing spring 51. The preload on the gear member 44 will effectively maintain the door 23 in the horizontal position as shown in FIG. 2 under a preselected normal door loading including a rack of dishes (not shown). It is noted also that the door biasing spring 39 is extended to at least partially compensate for the weight of the door 23 and the weight of the rack and dishes.

The biasing effect of the door spring 39 and the preload on the gear member spring 51 cooperate to effectively maintain the door 23 in the horizontal position as shown with a preselected door loading such as a 45 pound load of rack and dishes. If, however, the load on the door exceeds a normal maximum load, such as a total of 50 pounds, the preload force on the gear member 44 will be overcome and the door 23 will move downwardly from the horizontal position.

Referring now to FIG. 3, the dishwasher appliance door 23 is shown in the overload position with an edge 60 of the door engaging the floor surface 11. When the overload is applied to the open door 23, the forces are transmitted through the

engaging gear segments

40 and 45 and the movement of the arcuate arm 33 about the hinge pin 29 effects movement of the tub-mounted gear segment 45 about the pivot pin 46. As the gear segment 45 is moved about the pivot pin 46, the gear member biasing spring 51 is extended to provide additional resistance to the movement of the door 23.

Assuming that the overload remains on the appliance door 23, the door will move to the position shown in FIG. 3 with the edge 60 of the door engagingthe floor. Immediately prior to the engagement of the door 23 with the floor 11, the center line 61 of the gear member biasing spring 51 passes over the pivot point 46 of the gear member 44 as an over-center spring. The overcenter spring characteristic biases the gear member 44 in a clockwise direction about the pivot pin 46 and effectively holds the door 23 against the floor to prevent spring back of the door toward the cabinet structure 10.

It is thus possible to understand that the gear action, in cooperation with the forces acting through the springs, give controlled movement to an overloaded door. In the absence of movement control means as disclosed in the instant invention, the door could operate as a freely released door and could cause injury or damage as it moves unchecked to the floor. A feature of the instant invention would thus be the limiting of the rate of movement of the door under an overloading thereof.

The door 23 may be easily reset to its normal open position simply by manually lifting the door from the floor so that the spring 51 goes back over center to reposition the door for subsequent safe operation.

Referring to FIG. 4, there is shown an alternate embodiment in which a linkage system replaces the mating gear segments shown in FIGS. 1 through 3. This system is operable on a door 23 similar to that shown in FIGS. 1 through 3 and also includes an arcuate arm portion 69 mounted on the movable door 23. The door is similarly biased by a spring 39 operating between the end of the arcuate arm 69 and the supporting frame 14 of the appliance.

In this alternate embodiment, a linkage in the form of a cable 70 is attached to the end of the arcuate arm 69 and to a pulley or wheel member 71 that isrotatably mounted to the tub member 13. A plate 73 is fixedto the pulley 71 for rotation therewith and includes a flanged end 74 for receiving one end of a biasing spring 75 of which the opposite end is fixed to the tub 13 through a bracket 76 mounted thereon. The opposite end 79 of the pulley-mounted plate 73 is engageable with an adjustable stop 80 fixed to the side of the tub 13.

In this alternate embodiment, the biasing spring 75 is connected between the plate 73 and the tub 13 and is preloaded to maintain the plate ,73 in the position shown in FIG. 4 for locating the door 23 to the substantially horizontal position. Upon the application of an overload to the door 23, the door will move from the position shown downwardly toward the floor l1 and the overload force will be transmitted through the cable 70 to the rotatably mounted pulley 71 and plate 73. The cable will unwind from the pulley 71 and the pulley and plate assembly will move in a clockwise direction as the door moves toward the floor. Immediately prior to the point at which the door 23 engages the floor 11, the spring 75 will pass over the pivot point 81 so that the pulley 71 is biased in a clockwise direction. This corresponds to the over-center operation described in FIG. 1. The flanged end 74 of the plate 73 will be seen that as the spring 75 extends to apply greater loading on the plate 73 the moment arm of the force acting about the pivot point 81 is reduced. The spring 51 shown in FIG. 1 may also be relocated to achieve this constant torque operation if desired.

The plate 73 and pulley 71 may be reset to the normal preloaded condition by the attachment of a cable or linkage (not shown) to the plate and manually operable for moving the plate and pulley assembly in a counterclockwise direction and passing the spring 75 back over the pivot point 81 so that the mechanism returns to its normal full line position as shown in FIG. 4.

Referring now to FIG. 5 there is shown'a still further embodiment of the instant invention in which a detent mechanism is substituted forthe meshing gear segments of FIGS. 1, 2, and 3 and for the linkage system of FIG. 4. In the embodiment of FIG. 5, a dishwasher includes a hinged door 23 as shown in the previous figures. An arcuate arm portion 88 is attached to the movable door and extends into the space between the tub member 13 and the outer enclosure as previously shown and includes an undulating cam surface 89 on the outer arcuate surface adjacent the rear end 90. The cam surface 89 is engageable by the plunger 91 movably mounted on the wall of the tub 13 by flanged bracket 93 fixed to the wall. The plunger 91 is biased in a generally downward direction for engagement with the camsurface 89 of the arcuate arm 88 by a'spring 94 operating between the upper flange 95 of the bracket 93 and a pin 96 fixed to the plunger 91.

The plunger 91 engages the arcuate arm 88 next to a first undulation 98 of the cam surface 89 and under preload biasing of the spring 94 yieldingly maintains the door 23 in the substantially horizontal open position as shown in FIG. 5. If the load on the door 23 exceeds a predetermined maximum, the biasing force of the spring 94 is overcome and the plunger 91 is forced upwardly and rides over the first undulation 98. If the overload remains on the door 23, the door will move downwardly toward the floor and the plunger 91 will ride over the cam surface 89 to a point past the last undulation 99 to effectively maintain the door 23 in the overload position. If, however, the overload force-is momentary and is removed before the door engages the floor, the cooperation of the cam surface 89 and the plunger 91 will control movement of the door and position the door at some point between its normal horizontal position and the overload position.

This system may be easily reset by the operator by simply lifting the door 23and applying sufficient force to overcome the biasing of the plunger 91 so that the arcuate arm 88 may be moved in a clockwise direction about the hinge pin 29 to its normal position shown in FIG. 5.

It is therefore seen that the instant invention provides on built-in appliances having a door openable to a substantially horizontal position for preventing damage to the door or the appliance in case an overload is applied to the open door.

In the drawings and specification, there has been set forth a preferred embodiment of the invention and although specific terms are employed these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in form and the proportion of parts as well as the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of this invention as further defined in the following claims.

I claim: 1

1. In a front opening appliance including a cabinet structure supportable juxtaposed a substantially horizontal surface and having an access opening on one side; door means normally operable between a closed position covering said access opening and an open position extending substantially horizontally from said cabi net structure spaced above said horizontal surface and hinge means including a hinge pin juxtaposed the lower portion of said door means for pivotally supporting said door on said cabinet structure, wherein the improvement comprises: a first gear means mounted on said door means for movement with the door means about said hinge pin; second gear means movably mounted on said cabinet structure and operatively engageable with said first gear means; and biasing means for preloading said second gear means to a predetermined position for yieldingly restraining said first and second gear means to prevent movement of said door means beyond said horizontally extending open position with less than a predetermined loading on said door means, said first gear means being operable responsive to a loading on said door means exceeding said predetermined loading for overcoming the preloaded biasingof said second gear means and effecting controlled movement of said door means to an overload position at which a portion of said door means engages said horizontal surface.

2. In a front opening appliance as defined in claim ll wherein said door means and said first gear means is freely movable from said closed position to said open position and wherein said first gear means is engageable with said preloaded second gear means at said open position for effectively locating said door means in said open position.

3. In a front opening appliance as defined in claim 1 wherein said second gear means is mounted on a pivot pin supported by said cabinet structure and wherein said biasing means is in the form of a spring member operable as an over-center spring to preload said second gear means and resist movement of said second opening, a normal open position, and an overload position; hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure; and first biasing means connected between said cabinet structure and said door means for at least partially compensating for the weight of said door means as said door means is moved from said closed position, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure and including a first member in the form of an arm mounted on said door means for movement therewith and for movement relative to said cabinet structure, a second member movably mounted on said cabinet structure, stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; and second biasing means for biasing said second member into engagement with said stop means, said second member in said predetermined position being connectable with said first member only upon movement of said door means to said open position from said closed position whereby movement of said door means from said closed position to said open position is independent of said second biasing means, said first memher and said second member being cooperable with said second biasing means at said open position to yieldably locate said door means in said open position with less than a predetermined loading thereon, said door movement control means being operable for effecting an operative connection of said second biasing means to said door means for biasingly resisting movement of said door means toward said overload position with greater than said predetermined loading thereon.

' means for movement therewith, said second member is pivotally mounted on said cabinet structure, and wherein said door movement control means further includes an intermediate linkage means operatively connecting said first and second members at said predetermined position to effectively locate said door means in said open position.

'7. In a front opening appliance as defined in claim 4 wherein said second biasing means is further operable for yieldably maintaining said door means in said overload position.

8. In a from opening appliance as defined in claim 7 wherein said second biasing means is in the form of an over-center spring operable in the overload position of said door meansfor applying a generally opposite force to said second member for yieldably maintaining said door means in said overload position and wherein said door means is manually operable from said overload position to said open position for resetting said first and second members to their respective positions corresponding to the open position of said door means for further control of said door means.

9. In a front opening appliance including a cabinet structure supportable juxtaposed a substantially horizontal surface and having an access opening on one side; door means normally operable between a closed position covering said access opening and a substantially horizontal open position spaced above said horizontal surface; hinge means for movably supporting said door means on said cabinet structure; and first biasing means operative between said cabinet structure and said door means at least partially compensating for the weight of said door means as said door means is moved from said closed position, wherein the improvement comprises: a first member in the form of an arm mounted on said door means for movement therewith and for movement relative to said cabinet structure; a second member movably mounted on said cabinet structure; stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; and second biasing means forbiasing said second member into a preloaded engagement with said stop means, said second member in said predetermined position being engageable with said first member only upon movement of said door means to said open position from said closed position whereby movement of said door means from said closed position to said open position is independent of said second biasing means, said first member and said second member being operable at said open position for connecting said second biasing means to said door means to locate said door means in said open position and'to effectively prevent movement of said door means beyond said substantially horizontal open positionwith less than a predetermined loading thereon, said second member being movable from said predetermined position in cooperation with said first member responsive to loading on said door means exceeding said predetermined loading for maintaining the connection of said second biasing means to said door means during at least a portion of the movement of said door means between said open position and an overload position for applying a force to said door means in a direction opposing movement of said door means toward said overload position and assisting in the return of said door means toward said open position and thereby effecting controlled movement of said door means between said open position and said overload position at which a portion of said door means engages said horizontal surface.

10. In a front opening appliance as defined in claim 9 wherein said second biasing means is in the form of an over-center spring connected between said second member and said cabinet structure and operable for resisting movement of said door means from said open position to said overload position and further operable for yieldably maintaining said door means in said overload position upon movement of said door means to the overload position.

11. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable relative to said cabinet-structure between a closed position covering said access opening, a normalopen position, and an overload position; and hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure, wherein the improvement comprises: door movement control means for controlling movement of saiddoor means relative to said cabinet structure to locate said door means in said open position with less than a predetermined loading thereon and to control movement of said door means toward said overload ns position with greater than said predetermined loading thereon, said door movement control means including a first member mounted on said door means for movement therewith,

a second member movably mounted on said cabinet structure, stop means on said cabinet structure for engagement with said second member to locate said second member for engagement with said first member at the open position of said door means, and biasing means for biasing said second member into engagement with said stop means, said biasing means comprising an over-center spring connected between said cabinet structure and said second member for operative connection to said door means through said first and second members at said open position of said door means, said over-centerspring having a preloaded condition to effectively locate said door means in said open position and operable for resisting movement of said door means from said open position toward said overload position, said over-center spring being movable relative to said cabinet structure as said door means moves toward said overload position and operative in said overload position for biasing said second member away from said stopv means to yieldably maintain said door means in said overload position.

12. Ina front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable between a closed position covering said access opening and an open position extending generally outwardly from said cabinet structure; and hinge means juxtaposed the lower portion of said door means for pivotally supporting said door means on said cabinet structure, wherein the improvement comprises: a first door movement control member mounted on said door means; a second door movement control member movably mounted on said cabinet structure; stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; means for effecting operative interconnection of said first member and said second member at said open position; and biasing means in the form of an overcenter spring connected between said cabinet structure and said second member and in a first posture being operable on said second member to preload said second member into engagement with said stop member, said first and second members, said interconnection means and said biasing means being cooperable to resist movement of said door means from said open position toward said overload position for yieldably maintaining said door means in said open position with less than a predeterminded loading thereonand being responsive to a predetermined overload on said door means in said open position for effecting controlled movement of said door means from said open position to an overload position, said biasing means being movable to asecond posture upon movement of said door means to said overload position and operable in said second posture for applying a generally opposite force to said second member to yieldably maintain said door means in said overload position, said door means being manually movable from said overload position toward said open position for resetting said first and second members and said interconnection means to positions corre sponding to the open position of said door means.

13. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable relative to said cabinet between a closed position covering said access opening, a normal open position, and an overload position; hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure; and first biasing means operative between said cabinet structure and said door means at least partially compensating for weight of said door means as door means is moved from said closed position, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure and including a first member mounted on said door means for movement therewith, a second member movably mounted on said cabinet structure, stop means on said cabinet structure for engagement with said second member to locate said second member for engagement with said first member at the open position of said door means, and secondbiasing means for biasing said second member into engagement with said stop means, said door movement control means being operable to locate said door means in said open position with less than a predetermined loading thereon and to control movement of said door means during movement of said door means from said open position toward said overload position with greater than said predetermined loading thereon, said preloaded second biasing means being operable during at least a portion of the movement of said door means from said open position toward said overload position for resisting continued movement of said door means with an opposing force at least as great as the force resisting movement from the open position,

14. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means movable relative to said cabinet structure between a closed position covering said access opening, a normal open position, and an overload position; and hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure, said door movement control means including a first member mounted on said door means, a second member pivotally mounted on said cabinet structure, stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position, biasing means for biasing said second member into engagement with said stop means, and means comprising a cable for operatively connecting said first member to said second member upon movement of said door means to the open position from said closed position whereby said biasing means becomes initially connected to said door means at the open position of said door means, said door movement control means being operable to yieldably locate said door means in said open position with less than a predetermined loading thereon and being operable through the cable connection for directly resisting movement of said door means from said open position toward said overload thereon.

a x: s

Claims

1. In a front opening appliance including a cabinet structure supportable juxtaposed a substantially horizontal surface and having an access opening on one side; door means normally operable between a closed position covering said access opening and an open position extending substantially horizontally from said cabinet structure spaced above said horizontal surface and hinge means including a hinge pin juxtaposed the lower portion of said door means for pivotally supporting said door on said cabinet structure, wherein the improvement comprises: a first gear means mounted on said door means for movement with the door means about said hinge pin; second gear means movably mounted on said cabinet structure and operatively engageable with said first gear means; and biasing means for preloading said second gear means to a predetermined position for yieldingly restraining said first and second gear means to prevent movement of said door means beyond said horizontally extending open position with less than a predetermined loading on said door means, said first gear means being operable responsive to a loading on said door means exceeding said predetermined loading for overcoming the preloaded biasing of said second gear means and effecting controlled movement of said door means to an overload position at which a portion of said door means engages said horizontal surface.

2. In a front opening appliance as defined in claim 1 wherein said door means and said first gear means is freely movable from said closed position to said open position and wherein said first gear means is engageable with said preloaded second gear means at said open position for effectively locaTing said door means in said open position.

3. In a front opening appliance as defined in claim 1 wherein said second gear means is mounted on a pivot pin supported by said cabinet structure and wherein said biasing means is in the form of a spring member operable as an over-center spring to preload said second gear means and resist movement of said second gear means in a first direction while oriented on one side of said pivot pin and operable for biasing said second gear means in said first direction to effectively retain said door means in said overload position after the spring passes over the pivot pin responsive to movement of said door means to said overload position.

4. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable relative to said cabinet between a closed position covering said access opening, a normal open position, and an overload position; hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure; and first biasing means connected between said cabinet structure and said door means for at least partially compensating for the weight of said door means as said door means is moved from said closed position, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure and including a first member in the form of an arm mounted on said door means for movement therewith and for movement relative to said cabinet structure, a second member movably mounted on said cabinet structure, stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; and second biasing means for biasing said second member into engagement with said stop means, said second member in said predetermined position being connectable with said first member only upon movement of said door means to said open position from said closed position whereby movement of said door means from said closed position to said open position is independent of said second biasing means, said first member and said second member being cooperable with said second biasing means at said open position to yieldably locate said door means in said open position with less than a predetermined loading thereon, said door movement control means being operable for effecting an operative connection of said second biasing means to said door means for biasingly resisting movement of said door means toward said overload position with greater than said predetermined loading thereon.

5. In a front opening appliance as defined in claim 4 wherein said first member includes a gear segment adjacent one end thereof and wherein said second member includes a gear portion initially engageable with the gear segment of said first member at said predetermined position to effectively locate said door means in said open position and operable as mating gears during movement of said door means from said open to said overload position.

6. In a front opening appliance as defined in claim 4 wherein said first member is mounted on said door means for movement therewith, said second member is pivotally mounted on said cabinet structure, and wherein said door movement control means further includes an intermediate linkage means operatively connecting said first and second members at said predetermined position to effectively locate said door means in said open position.

7. In a front opening appliance as defined in claim 4 wherein said second biasing means is further operable for yieldably maintaining said door means in said overload position.

8. In a front opening appliance as defined in claim 7 wherein said second biasing means is in the form of an over-center spring operable in the overload position of said door means for applying a generally opposite force to said second member for yieldably maintaining said door means in said overload poSition and wherein said door means is manually operable from said overload position to said open position for resetting said first and second members to their respective positions corresponding to the open position of said door means for further control of said door means.

9. In a front opening appliance including a cabinet structure supportable juxtaposed a substantially horizontal surface and having an access opening on one side; door means normally operable between a closed position covering said access opening and a substantially horizontal open position spaced above said horizontal surface; hinge means for movably supporting said door means on said cabinet structure; and first biasing means operative between said cabinet structure and said door means at least partially compensating for the weight of said door means as said door means is moved from said closed position, wherein the improvement comprises: a first member in the form of an arm mounted on said door means for movement therewith and for movement relative to said cabinet structure; a second member movably mounted on said cabinet structure; stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; and second biasing means for biasing said second member into a preloaded engagement with said stop means, said second member in said predetermined position being engageable with said first member only upon movement of said door means to said open position from said closed position whereby movement of said door means from said closed position to said open position is independent of said second biasing means, said first member and said second member being operable at said open position for connecting said second biasing means to said door means to locate said door means in said open position and to effectively prevent movement of said door means beyond said substantially horizontal open position with less than a predetermined loading thereon, said second member being movable from said predetermined position in cooperation with said first member responsive to loading on said door means exceeding said predetermined loading for maintaining the connection of said second biasing means to said door means during at least a portion of the movement of said door means between said open position and an overload position for applying a force to said door means in a direction opposing movement of said door means toward said overload position and assisting in the return of said door means toward said open position and thereby effecting controlled movement of said door means between said open position and said overload position at which a portion of said door means engages said horizontal surface.

11. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable relative to said cabinet structure between a closed position covering said access opening, a normal open position, and an overload position; and hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure to locate said door means in said open position with less than a predetermined loading thereon and to control movement of said door means toward said overload ns position with greater than said predetermined loading thereon, said door movement control means including a first memBer mounted on said door means for movement therewith, a second member movably mounted on said cabinet structure, stop means on said cabinet structure for engagement with said second member to locate said second member for engagement with said first member at the open position of said door means, and biasing means for biasing said second member into engagement with said stop means, said biasing means comprising an over-center spring connected between said cabinet structure and said second member for operative connection to said door means through said first and second members at said open position of said door means, said over-center spring having a preloaded condition to effectively locate said door means in said open position and operable for resisting movement of said door means from said open position toward said overload position, said over-center spring being movable relative to said cabinet structure as said door means moves toward said overload position and operative in said overload position for biasing said second member away from said stop means to yieldably maintain said door means in said overload position.

12. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable between a closed position covering said access opening and an open position extending generally outwardly from said cabinet structure; and hinge means juxtaposed the lower portion of said door means for pivotally supporting said door means on said cabinet structure, wherein the improvement comprises: a first door movement control member mounted on said door means; a second door movement control member movably mounted on said cabinet structure; stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position; means for effecting operative interconnection of said first member and said second member at said open position; and biasing means in the form of an over-center spring connected between said cabinet structure and said second member and in a first posture being operable on said second member to preload said second member into engagement with said stop member, said first and second members, said interconnection means and said biasing means being cooperable to resist movement of said door means from said open position toward said overload position for yieldably maintaining said door means in said open position with less than a predeterminded loading thereon and being responsive to a predetermined overload on said door means in said open position for effecting controlled movement of said door means from said open position to an overload position, said biasing means being movable to a second posture upon movement of said door means to said overload position and operable in said second posture for applying a generally opposite force to said second member to yieldably maintain said door means in said overload position, said door means being manually movable from said overload position toward said open position for resetting said first and second members and said interconnection means to positions corresponding to the open position of said door means.

13. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means operable relative to said cabinet between a closed position covering said access opening, a normal open position, and an overload position; hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure; and first biasing means operative between said cabinet structure and said door means at least partially compensating for weight of said door means as door means is moved from said closed position, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure and including a first member mounted on said door means for movement therewith, A second member movably mounted on said cabinet structure, stop means on said cabinet structure for engagement with said second member to locate said second member for engagement with said first member at the open position of said door means, and second biasing means for biasing said second member into engagement with said stop means, said door movement control means being operable to locate said door means in said open position with less than a predetermined loading thereon and to control movement of said door means during movement of said door means from said open position toward said overload position with greater than said predetermined loading thereon, said preloaded second biasing means being operable during at least a portion of the movement of said door means from said open position toward said overload position for resisting continued movement of said door means with an opposing force at least as great as the force resisting movement from the open position.

14. In a front opening appliance including a cabinet structure having an access opening on one generally vertical side; door means movable relative to said cabinet structure between a closed position covering said access opening, a normal open position, and an overload position; and hinge means juxtaposed the lower portion of said door means for movably supporting said door means on said cabinet structure, wherein the improvement comprises: door movement control means for controlling movement of said door means relative to said cabinet structure, said door movement control means including a first member mounted on said door means, a second member pivotally mounted on said cabinet structure, stop means mounted on said cabinet structure for engagement with said second member to locate said second member at a predetermined position, biasing means for biasing said second member into engagement with said stop means, and means comprising a cable for operatively connecting said first member to said second member upon movement of said door means to the open position from said closed position whereby said biasing means becomes initially connected to said door means at the open position of said door means, said door movement control means being operable to yieldably locate said door means in said open position with less than a predetermined loading thereon and being operable through the cable connection for directly resisting movement of said door means from said open position toward said overload position with greater than said predetermined loading thereon.