Abstract:
A method and apparatus for appliance installation and leveling using a leveling caster. The leveling caster includes a top shelf connected to wheels by a scissors type structure. The height of the scissors type structure can be adjusted using an adjustment bolt from the front of the appliance, without requiring access to the rear of the appliance. The leveling caster is adjustable over a wide range of heights, is strong enough to bear heavy appliances, and allows height adjustment while minimizing incidental horizontal motion.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to the field of appliances, and particularly to installation and leveling of appliances. 
     BACKGROUND OF THE INVENTION 
     Household and commercial appliances, for example stoves, ranges, dishwashers, refrigerators, clothes washers and dryers, and other appliances, require careful installation so that they operate properly and fit correctly into their surrounding environment. Three important measures of the installation of an appliance are the degree to which the appliance is level, the height of the appliance, and the ease of moving the appliance, for example during installation, maintenance, or cleaning. 
     The performance of many appliances can be diminished if they are not level during operation. For example, an oven that is not level will often bake cakes that are also not level. If the burners or other cooking surfaces of a stove are not level, foods such as eggs in a frying pan may pool on one side and cook unevenly. Refrigerators may have systems, such as cooling or ice making systems, which function best when they are level. Clothes washers may become unbalanced more easily when they are not installed level. For this reason, devices for leveling appliances are known in the art. 
     The height of an appliance is also often important. It may be advantageous to adjust the height of an appliance to match its surrounding cabinetry or countertop. A cook may wish to adjust the height of an appliance for comfort during use, or for other reasons. Even small differences in height or level of an appliance can create a perception of low quality or defective construction, of both the appliance and its surroundings. For these reasons, devices to adjust the height of an appliance are known in the art. 
     Appliances are often heavy and awkwardly shaped. It may be difficult to maneuver appliances during installation, especially into limited or confined spaces. It may also be necessary to move appliances to allow maintenance and cleaning of the appliances themselves and the areas around the appliances. For these reasons, it is common to place wheels on appliances. 
     It may be necessary or desirable to level an appliance, or adjust the height of an appliance, after the appliance has been placed in its final position, especially when the appliance is not easily movable. Even a movable appliance, e.g. one with wheels, may be most conveniently leveled or fitted into place after it is moved into its final horizontal position, to exactly match the countertops and surrounding cabinetry. Adjustment of the height or level of the rear of an appliance can be difficult, however, because access to the rear of an appliance may be very limited, for example in the case of a refrigerator or stove fitted into a space between surrounding countertops. For these reasons, devices to adjust the height of the rear of an appliance from the front are known in the art. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a method and apparatus which allows the height and level of an appliance to be adjusted from the front of the appliance without requiring access to the rear of the appliance. The method and apparatus according to the invention incorporates a shelf supported on wheels by a scissors-type structure. By turning a forward-facing adjustment bolt in one direction, the scissors-type structure extends to increase the height of the shelf above the wheels. By turning the forward-facing adjustment bolt in the other direction, the scissors-type structure compresses under the weight of the appliance to decrease the height of the shelf above the wheels. 
     The method and apparatus according to the invention includes a scissors-type structure which allows vertical adjustment of height and level across a wide range of heights while minimizing horizontal movement incidental to the vertical adjustment. The method and apparatus is strong enough to accommodate even heavy appliances such as commercial stoves and refrigerators. The method and apparatus includes wheels to allow the appliance to be moved into and out of its final installed position without requiring access to the rear of the appliance. 
     Further objects, features, and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of an appliance being installed between surrounding countertops and cabinetry. 
         FIG. 2  is a side view of an appliance including a preferred embodiment of a leveling caster according to the invention. 
         FIG. 3  is a front view of an appliance including a preferred embodiment of a leveling caster according to the invention. 
         FIG. 4  is a bottom view of an appliance including a preferred embodiment of a leveling caster according to the invention. 
         FIG. 5  is a front perspective view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 6  is a rear perspective view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 7  is a left side view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 8  is a right side view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 9  is a right side view of a preferred embodiment of a leveling caster according to the invention, where the height of the leveling caster has been increased. 
         FIG. 10  is an exploded perspective view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 11  is a perspective view from a point below a preferred embodiment of a leveling caster according to the invention. 
         FIG. 12  is a bottom view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 13  is a top view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 14  is a front view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 15  is a rear view of a preferred embodiment of a leveling caster according to the invention. 
         FIG. 16  is a front view of an embodiment of a front leg for an appliance. 
         FIG. 17  is a side view of an embodiment of a front leg for an appliance. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the drawings,  FIG. 1  shows a perspective view of an appliance, indicated generally at  11 , prior to installation between surrounding countertops, indicated generally at  12 , and cabinetry, indicated generally at  13 . The appliance  11  preferably includes at least one front support leg, indicated generally at  14 . The rear support for the appliance  11  is hidden in the perspective view of FIG.  1 . 
       FIG. 2  provides a side view of an appliance  11 , which shows a preferred embodiment of a leveling caster according to the invention, indicated generally at  10 , located at the rear of the appliance  11 . As best shown in the front view of an appliance  11  found in  FIG. 3 , and in the bottom view of an appliance  11  found in  FIG. 4 , the appliance may include multiple leveling casters  10  and multiple front support legs  14 . 
     As shown in  FIGS. 5 and 6 , a leveling caster  10  according to the invention includes an adjustment bolt  32  passing through a front adjustment bolt bracket  30  and a rear adjustment bolt bracket  31 , and which may be used to adjust the height of the leveling caster  10 . 
     As best shown in  FIGS. 3 and 4 , the leveling casters  10  are preferably offset horizontally from the front support legs  14 , so that the front support legs  14  do not obstruct access from the front of the appliance  11  to the adjustment bolts  32  on the leveling casters  10 . This allows the height of the leveling casters  10  to be adjusted from the front of the appliance  11 , preferably using a socket wrench  15 , without requiring access to the rear of the appliance  11 . As best shown in  FIG. 2 , the minimum height of the leveling caster  10  (when fully compressed) is preferably chosen to allow a power tool, for example a socket wrench  15  attached to a cordless power drill  16 , to fit underneath the appliance to allow easy and rapid adjustment of the height of the leveling caster, although this is not required. 
     The construction of a preferred embodiment of a leveling caster  10  according to the invention is perhaps best illustrated in  FIGS. 9 ,  10 , and  11 . In the side view of  FIG. 9 , the height of the leveling caster  10  has been increased, thereby revealing the internal construction of the leveling caster  10 .  FIG. 10  provides an exploded perspective view which further illustrates the construction of a preferred embodiment of a leveling caster according to the invention.  FIG. 11  provides a perspective view of the underside of the leveling caster  10 , further illustrating the mechanism used to adjust the height of the leveling caster  10 . 
     As best shown in  FIGS. 10 and 11 , a preferred embodiment of a leveling caster  10  according to the invention has two wheels  40  which may be separated by an axle spacer  43 . The two wheels  40  and the axle spacer  43  are preferably mounted on an axle  41  and secured on the axle, for example using an axle nut  42 . 
     As best shown in  FIGS. 9 and 10 , a preferred embodiment of a leveling caster  10  according to the invention has a top shelf  20 , preferably made of sheet metal and one or more wheels  40  mounted on an axle  41 . As best shown in  FIGS. 5 and 13 , the top shelf  20  may have one or more mounting holes  21  which can be used to secure the leveling caster  10  to the frame of an appliance  11 , for example using screws, rivets, or nuts and bolts. The top shelf  20  is connected to the axle  41  by a scissors-type support structure, indicated generally at  27 , whose height may be adjusted, thereby allowing the overall height of the leveling caster  10  to be adjusted. 
     As best shown in  FIG. 11 , a preferred embodiment of a leveling caster  10  according to the invention has a front adjustment bolt bracket  30 , a rear adjustment bolt bracket  31 , an adjustment bolt  32 , and an adjustment nut  33 . The adjustment bolt  32  passes through a hole in the front adjustment bolt bracket  30  and through a hole in the rear adjustment bolt bracket  31  where it is threaded through an adjustment nut  33 . The adjustment nut  33  may be permanently attached to the rear adjustment bolt bracket  31 , for example by welding. 
     By tightening the adjustment bolt  32  in the adjustment nut  33 , the front adjustment bolt bracket  30  is drawn toward the rear adjustment bolt bracket  31 , extending the scissors-type support structure  27  and increasing the height of the leveling caster  10 . Similarly, by loosening the adjustment bolt  32  in the adjustment nut  33 , the weight of the appliance  11  compresses the scissors-type support structure  27 , forcing the front adjustment bolt bracket  30  and the rear adjustment bolt bracket  31  apart and reducing the height of the leveling caster  10 . 
     As illustrated by the left side view found in FIG.  7  and the right side view found in  FIG. 8 , the construction of the scissors-type support structure  27  which connects the top shelf  20  to the axle  41  is essentially the same on the left and right sides of the leveling caster  10 , so the following description applies to both the right and left sides. 
     As best shown in  FIGS. 9 and 10 , the scissors-type support structure  27  of a preferred embodiment of a leveling caster  10  according to the invention has an upper rear support arm  22 , a lower rear support arm  23 , an upper front support arm  24 , a lower front support arm  25  and an inside support arm  26 . Each of these five support arms is preferably formed of sheet metal and elongated, with an upper end, a lower end, and a middle section, although they may differ in length. 
     The lower end of the lower rear support arm  23  and the lower end of the lower front support arm  25  are pivotably connected together and to the axle  41 , for example by passing the axle  41  through a hole in the lower end of the lower rear support arm  23  and also through a hole in the lower end of the lower front support arm  25 . 
     The upper end of the lower rear support arm  23  is pivotably connected to the lower end of the upper rear support arm  22  and to the rear adjustment bolt bracket  31 , for example using a pivoting rivet  44 . The upper end of the upper rear support arm  22  is pivotably connected to the top shelf  20 , for example using a pivoting rivet  44 . The lower end of the inside support arm  26  is pivotably connected to a point in the middle section of the lower rear support arm  23 , for example using a pivoting rivet  44 . 
     The upper end of the lower front support arm  25  is pivotably connected to the lower end of the upper front support arm  24  and to the front adjustment bolt bracket  30 , for example using a pivoting rivet  44 . The upper end of the upper front support arm  24  and the upper end of the inside support arm  26  are pivotably connected to each other and to the top shelf  20 , for example using a pivoting rivet  44  and a washer  45 . 
       FIGS. 12-15  provide additional illustration of the construction of a preferred embodiment of a leveling caster  10  according to the invention.  FIG. 12  shows the details of the underside of the leveling caster  10 .  FIG. 13  shows the details of the top side of the leveling caster  10 .  FIG. 14  shows the details of the front of the leveling caster  10 .  FIG. 15  shows the details of the rear of the leveling caster  10 . 
     As best shown in  FIGS. 2 ,  3 , and  4 , an appliance  11  may include one or more front support legs  14  which provide support for at least a portion of the appliance. For example, the appliance  11  shown in  FIGS. 3 and 4  uses three leveling casters  10  to support the rear of the appliance  11 , and three front support legs  14  to support the front of the appliance. The front support legs  14  may be of any conventional construction. The front support legs  14  may be adjustable in height, or of fixed height. The front support legs  14  may be avoided entirely by using leveling casters  10  exclusively to support the appliance  11 . 
     As shown in  FIGS. 16 and 17 , in a preferred embodiment the front support legs  14  have an upper section  18  which nests inside a lower section  17 , and an adjustment mechanism (not shown) which is used to adjust the height of the front support legs  14 . 
     There are various possibilities with regard to alternative embodiments and applications of a leveling caster according to the invention. 
     Although the leveling caster may be used at the rear of an appliance, it may also be used at the front of an appliance, instead of or in addition to the front support legs  14 , by replacing one or more of the support legs  14  with one or more leveling casters  10 . 
     Instead of using a horizontal offset to avoid obstructing the leveling casters  10 , a hole could be placed in the front support leg or the adjustment bolt  32  could be mounted at an angle. Alternatively, a tool which provides a built-in offset could be used instead of a tool with a straight shaft. 
     Although an ordinary machine bolt is used as the adjustment bolt  32  in a preferred embodiment, other types of structures, for example, one or more flat head screws, phillips head screws, alien head screws, or ratchets may be used instead of or in addition to the adjustment bolt  32  to cause the scissors-type support structure to extend or compress. Other types of tools, for example a screwdriver or alien wrench could be used instead of a socket wrench  15  or power drill  16 . To resist unwanted changes in height or level caused by vibration or other reasons, the degree of compression or extension of the scissors-type support structure could be lockable after adjustment, for example by using an aircraft-type nut, a lock nut, or a lock washer instead of or in addition to the adjustment nut  33 , or by using a wedge, pin, or other structure to lock the position of the adjustment mechanism. 
     Although two wheels  40  and an axle spacer  43  mounted on an axle  41  and secured with an axle nut  42  are used in a preferred embodiment, other types of rollable structures could be used. For example, there could be a greater or lesser number of wheels, or some combination of the wheels  40 , axle spacer  43 , and axle  41  may be combined into a single piece, for example a molded roller. Instead of an axle nut, other means for securing the wheels and axle could be used, for example a lock washer, a cotter pin, a molded or heat-formed structure, or a structure or material held on by friction or adhesion, for example molded plastic or rubber, or glue. One or ore of the wheels could be lockable to prevent rolling after installation, for example using a pin inserted through a slotted nut or a friction-based brake assembly. 
     Although a top shelf  20  is used in a preferred embodiment, other structures could be used. For example, the top shelf could be eliminated by mounting the scissors-type structure directly to the frame of the appliance  11 . Alternatively, the top shelf could be formed in different shapes or in multiple pieces. 
     Similarly, different scissors-type support structures may be used instead of the particular scissors-type support structure of the preferred embodiment. There may be a greater or lesser number of support arms, for example the inside support arm shown in the preferred embodiment could be eliminated. The support arms may have different shapes than those shown in the preferred embodiment. There may be only one scissors-type support structure, or more than two pairs of scissors-type support structures, instead of the two pairs of scissors-type support structures found in the preferred embodiment (one pair on each side). 
     It is understood that the invention is not confined to the embodiments set forth herein as illustrative, but embraces all such forms thereof as come within the scope of the following claims.