FIELD OF THE INVENTION 
   The invention relates to an assembly of the type which can be positioned to change the direction of an appliance in the horizontal and vertical directions. 
   BACKGROUND OF THE INVENTION 
   Directionally adjustable fans have long been known. Such fans are useful when it is desirable to direct the airflow from the fan in a specific direction without moving the base of the fan. 
   Directionally adjustable fans that are capable of pivoting about both the vertical axis and the horizontal axis are typically designed with two pivot mechanisms—one for each axis. One type of pivot mechanism which allows adjustment of the vertical direction of the airflow includes coupling the fan assembly to rotatable mounts at each of the two ends of the diameter of the fan assembly forming an axis of rotation that is parallel to the floor of the base of the fan. Alternatively, the fan assembly is coupled to an arm which is rotatably mounted to the base, thereby allowing the fan to rotate about the horizontal axis defined by the rotatable mount. The horizontal direction of the airflow is adjusted by coupling the fan to the base through a mounting that is rotatable about the vertical axis. According to either design, adjusting the direction of airflow from the fan in both the vertical and horizontal axis requires the separate adjustment of two rotatable mountings. 
   Once the fan is adjusted so that the airflow generated flows in the desired direction, a mechanism is typically employed to preserve the adjustments in the event an external force is applied to the fan that would alter the position of the fan. Typically, the angular adjustments made to the fan are maintained by friction within the rotatable mount. Another way of preserving the angular adjustments is by tightening a screw coupled to each rotatable mount to increase the friction. Additionally, the screw could be loosened to allow adjustments to be made more easily. These frictional forces may be further increased by employing a gear structure of radially extending teeth between the mounting contact surfaces. However, the gear teeth decrease the precision of the adjustments since the teeth must properly mesh at predefined positions. Also, the gears increase the difficulty in making the adjustments since the mount surfaces no longer smoothly glide as the mounting is rotated. 
   Similar mounting devices have been provided for other appliances in addition to fans. Space heaters have been rotatably mounted to allow for adjusting the direction of the heat. Mirrors are frequently attached to a table stand and provide two or more rotatable mountings so that the mirror can be adjusted about the vertical and horizontal axis. Rotatable mirror mountings can also be fixed to a wall by an extendable arm, thereby allowing the mirror to be pulled away from the wall and rotatably adjusted. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a pivot assembly that can be used with various appliances. The pivot assembly provides three degrees of freedom when positioning the appliance. The pivot may be used, for example, with a fan that is mounted on a base such that the direction of the airflow generated can be adjusted about all three coordinate axes by manipulating a single rotatable pivot mount. Any adjustments to the positioning of the rotatable pivot mount are maintained by the friction within the rotatable pivot mount. The ability to direct airflow through the manipulation of a single rotatable pivot mount provides a fast adjustment and allows for more accurate airflow direction. 
   The fan assembly includes a base unit and an arm. The arm includes a mounting end to which the blower unit of the fan is detachably coupled. The opposite end of the arm is provided with a spherical cap which is received by the base unit. The base unit includes a bottom portion and a top portion. The top portion includes an opening through which the arm extends. The opening of the top portion is smaller than the diameter of the spherical cap of the arm thereby preventing the arm from being unintentionally detached from the base. The opening is shaped such that it is substantially flush with the outer surface of the spherical cap. The bottom portion of the base unit exerts a force against the spherical cap such that the friction between the spherical cap of the arm and the top portion of the base will maintain the positional adjustment made to the arm. 
   In another embodiment of this invention the force exerted by the bottom portion of the base against the spherical cap of the arm is transmitted through a spherical cap mount. The spherical cap mount has an outer radius roughly equal to the inner radius of the spherical cap of the arm, such that the bottom of the spherical cap of the arm rests substantially flush against the outer surface of the spherical cap mount as the arm pivots and rotates. A force can be created by tightening the coupling of the top potion of the base unit and the bottom portion of the base unit so that the spherical cap of the arm is held tightly in between. Preferably, the force is created by including a spring in the bottom portion of the base unit which exerts the force against the spherical cap of the arm directly or transmits the force through the spherical cap mount. 
   In another embodiment of the invention the arm is extendable thereby providing an additional way to adjust the direction of the airflow. The arm may be of a telescoping type and provided with a locking mechanism for each segment of the telescoping arm. 
   The fan blower may include a handle coupled to the blower by which the rotatable pivot mount may be adjusted and the fan direction altered. The handle should be positioned so that it will act as a lever when rotating the fan about any axis, thereby reducing the amount of force required to overcome the friction force created within the rotatable pivot mount. 
   In another embodiment of this invention the opening of the top portion of the base unit can act as a pivot guide for positioning the arm by preventing the fan from being adjusted to certain positions. If the fan is pivoted too far off the vertical axis, the center of gravity may extend beyond the support area provided by the base and the fan may become unstable and topple over. The shape of the pivot guide can be adjusted to prevent the fan from pivoting to a position where the center of gravity of the fan extends beyond the support area provided by the base. 
   The pivot guide also provides increased stability of the fan when adjusted to certain positions. The pivot guide can provide inlets in which the arm rests, thus complementing the support provided by the frictional force exerted by the bottom potion of the base unit. Thus, while the arm is positioned in one of the inlets provided by the pivot guide, if the assembly is disturbed by an external force, the added stability decreases the likelihood of the fan being moved out of position. 
   Additionally, the pivot guide may be detachable from the base unit, thus making the shape of the top portion opening modifiable. Because the shape of the opening serves a decorative purpose as well as the functional purpose described above, the decorative element can be enhanced by allowing a user to select a pivot guide to match any desired esthetic or visual appearance. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other features of the present invention will be more readily apparent from the following detailed description and drawings of illustrative embodiments of the invention in which: 
       FIG. 1  is an exploded top front perspective view of a first embodiment of the invention; 
       FIG. 2  is a front elevation view of the first embodiment of the invention; and 
       FIG. 3  is a cross section view of the front view of  FIG. 2 . 
   


   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring now to the drawings the present invention is directed to a pivot mount assembly. The pivot may be used with almost any appliance, including a mirror, fan, or heater. By way of illustration, the pivot mount is discussed in conjunction with a fan assembly that allows the airflow generated to be adjusted along three axes by manipulating a single rotatable pivot mount. Any adjustments to the positioning of the rotatable pivot mount are maintained by the continuous friction at the rotatable pivot mount. The ability to direct airflow in one or more dimensions through the manipulation of a single rotatable pivot mount provides a fast adjustment and allows for more accurate airflow direction. 
   Referring now to  FIGS. 1-3 , the fan assembly includes a base unit  80  and an arm  30 . The arm  30  includes a pivot end having a spherical cap  70  and a receiving end  140  to which the blower  10  can be detachably coupled. An axis of the arm is defined by the pivot end and the receiving end  140 . The spherical cap  70  of the pivot end of the arm  30  has an inner radius, an outer radius, and a diameter  180 . The spherical cap  70  is received by the base unit  80 . The base unit  80  includes a bottom portion  40  and a top portion  50  coupled to the bottom portion  40 . It is further contemplated that the top portion  50  can be connected to the bottom portion  40  indirectly through another fixture interposed between the top portion  50  and bottom portion  40 . 
   The top portion  50  of the base unit  80  includes an opening  160  through which the arm  30  extends. The opening  160  of the top portion  50  is smaller than the diameter  180  of the spherical cap  70  of the arm  30  thereby preventing the arm from being unintentionally removed from the base  80 . Additionally, the opening  160  is shaped such that it is substantially flush with the outer surface of the spherical cap  70 . 
   Alternatively, the top portion  50  may include a pivot guide  60  through which the arm  30  extends. The pivot guide  60  is coupled to the top portion  50  of the base unit  80 , and the opening  120  of the pivot guide  60  is smaller than the diameter  180  of the spherical cap  70  of the arm  30 . The opening  120  of the pivot guide is shaped such that it is substantially flush with the outer surface of the spherical cap  70 . 
   The pivot guide  60  is preferably detachable from the top portion  50 , so that the shape of the opening  120  can be modified by replacing the pivot guide  60 . Alternatively, the opening  160  of the top portion  50  may be molded to form the pivot guide  60 . The embodiment in  FIG. 3  demonstrates that the pivot guide  60  can be coupled to the top portion shell  150 , from within the base unit  80 . Alternatively, the pivot guide  60  may be coupled to the top portion shell  150  from the exterior of the base unit  80  to facilitate the replacement of the pivot guide  60 . In a preferred embodiment the shape of the pivot guide  60  substantially conforms to the surface of a sphere having a radius roughly equal to the outer radius of the spherical cap  70  of the arm such that the outer surface of the spherical cap  70  of the arm is substantially flush with the inner surface of the pivot guide  60  as the arm  30  is positioned on the rotatable pivot mount. Because the shape of the opening  120  of the pivot guide  60  serves a decorative purpose as well as the functional purpose described above, the decorative aspect can be enhanced by allowing a user to select a pivot guide to match the desired esthetic or visual appearance. 
   The bottom portion  40  of the base unit  80  holds the spherical cap  70  of the arm  30  between the base unit  80  and the top portion  50  such that the outer surface of the spherical cap  70  will remain substantially flush with opening  120  of the top portion  50  of the base unit  80 . By tightly holding the spherical cap  70  of the arm  30 , the bottom portion  40  creates a friction force within the rotatable pivot mount that will statically maintain the position of the arm  30  as the axis of the arm is rotated into a selected orientation and angularly rotated about the selected orientation. 
   In one embodiment, the bottom portion  40  of the base unit  80  includes a spherical cap mount  100  which transmits a force against the spherical cap  70  of the arm  30 . The spherical cap mount  100  has an outer radius roughly equal to the inner radius of the spherical cap  70  of the arm  30 , such that when it is disposed within the bottom of the spherical cap  70  of the arm  30 , the outer surface of the spherical cap mount  100  rests substantially flush against the inner surface of the spherical cap  70  of the arm  30  as it pivots and rotates. 
   The frictional force created within the rotatable pivot mount can be increased or decreased by tightening or loosening the connection between the top portion  50  and the bottom portion  40  of the base unit  80  so that the force which presses the spherical cap  70  of the arm  30  within the base unit  80  is varied. In the embodiment shown in  FIG. 3  the frictional force is created in part by a spring  90  in the bottom portion  40  of the base unit  80  which exerts a force against the spherical cap  70  of the arm  30 , through the spherical cap mount  100 , and against the top portion  50 . Alternatively, the force can be transmitted through multiple springs or couplings. 
   It is further contemplated that the spherical cap mount  100  may be coupled to the bottom portion  40  of the base unit  80  by a threaded connection allowing the vertical height of the spherical cap mount  100  to be adjusted by rotating the spherical cap mount  100 , thereby adjusting the frictional force maintaining the static position of the arm  30 . Alternatively, the force may be transmitted by one or more screws disposed within the base unit  80  pressing the spherical cap mount  100  upwards against the spherical cap  70  of the arm  30 . 
   In another embodiment of the invention (not shown) the arm  30  is extendable thereby providing an additional way of adjusting the direction of the airflow. The arm  30  is preferably of a telescoping type and provided with a locking mechanism for each segment of the telescoping arm. 
   In a preferred embodiment, the fan blower  10  includes a handle  20  coupled to the fan blower  10  by which the rotatable pivot mount may be adjusted and the airflow direction altered. It is preferable that the handle  20  does not significantly obstruct either the air intake or exhaust of the fan unit. Additionally, as shown in  FIG. 1 , the handle  20  should be positioned so that it will act as a lever when rotating the fan about the vertical axis and when pivoting the fan about the spherical cap  70  of the arm  30 , thus reducing the amount of force required to overcome the friction force created within the rotatable pivot mount. 
   Another feature of this invention is that the pivot guide  60  of the top portion  50  of the base unit can act as a guide for positioning the arm  30  by preventing the fan from being adjusted to certain positions. If the fan blower  10  is pivoted too far off the vertical axis, the center of gravity may extend beyond the support area provided by the base unit  80 . The shape of the opening  120  of the pivot guide  60  can be adjusted to prevent the fan blower  10  from pivoting such that the center of gravity extends beyond the support area provided by the base unit  80 . If the base unit  80  is a circle, and the opening is located at the center of the base, then the opening  120  of the pivot guide  60  could be a circle having a particular radius to prevent the arm from pivoting too far. If the base unit  80  is in the shape of a triangular support, as shown in the embodiment in  FIGS. 1-3 , then the pivot guide  60  could be shaped so that the angle of rotation of the fan about the pivot would be greater when positioned over one of the ground supports than when positioned between two of the ground supports. 
   Another feature of this invention is that the pivot guide  60  of the top portion of the base unit can increase the stability of the fan when adjusted to certain positions. The friction created at the pivot should be sufficient to hold the fan in any position to which it is adjusted. However, if the frictional force should decrease through wear of the assembly or if a sudden external force is exerted on the assembly, the static friction may be overcome and the fan could be moved out of its adjusted position. The shape of the opening  120  of the pivot guide  60  can provide inlets  170  in which the arm  30  rests thus complementing the support provided by the frictional force exerted by the bottom potion  40  of the base unit  80 . Thus, if the assembly is disturbed by an external force while the arm  30  is positioned in one of the inlets  170  provided by the pivot guide  60 , the added stability of being positioned in the inlet  170  decreases the likelihood of the fan being moved out of position. 
   While the invention has been shown by way of reference to a rotatable pivot mount fan and particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the present invention may be utilized in any pivotable appliance and that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
A pivot assembly that can be used with various appliances. The pivot assembly provides up to three degrees of freedom when positioning the appliance. The pivot may be used, for example, with a fan that is mounted on a base such that direction of the airflow generated can be adjusted about three coordinate axes by manipulating a single rotatable pivot mount. The fan assembly includes a base unit and an arm to which an appliance may be detachably coupled. The opposite end of the arm is provided with a spherical cap which is received by the base unit. Any adjustments to the positioning of the rotatable pivot mount are maintained by the friction within the rotatable pivot mount. Additionally, the pivot mount may include a pivot guide to restrict the degree of rotation about the pivot, thereby increasing stability.