Swivel base with installation aid

Abstract

A shelf and swivel for supporting a shelf for rotation with respect to an underlying base, the shelf including an off-axis aperture, the swivel including a first member having a plurality of openings to receive fasteners for securing the swivel to the underlying base and a pair of downward projections straddling one of the openings. A second swivel member, coupled to the first swivel member for rotation about a vertical axis, is secured to a lower surface of the shelf so that the first member openings are serially accessible through the shelf aperture. A first fastener is installed through the shelf aperture and aligned first swivel member opening into the underlying base with sufficient force to embed the projections in the underlying base, thereby inhibiting movement of the first swivel member sufficiently to permit rotation of the shelf to serially expose additional first member openings to receive additional fasteners.

1 . A swivel for supporting a shelf unit for rotation with respect to an underlying base, the swivel comprising:
 a first member including a plurality of openings to receive fasteners for securing the first member to an underlying base,   a second member coupled to the first member for rotation about a vertical axis, the second member being mountable to a lower surface of a shelf unit, and   at least one projection projecting from a lower surface of the first member for engagement with the underlying base to facilitate a desired alignment of the first member relative to the underlying base.   
   
   
       2 . The swivel of  claim 1 , wherein the at least one projection comprises a pair of projections straddling one of the plurality of openings in the first member. 
   
   
       3 . The swivel of  claim 1 , wherein the second member has a contoured surface including at least one pair of adjacent lobes separated by an indentation and a follower is coupled to the first member and biasing means biases the follower into contact with the second member contoured surface. 
   
   
       4 . The swivel of  claim 3 , wherein the contoured surface is situated on a radial outside surface of the second member relative to said vertical axis. 
   
   
       5 . The swivel of  claim 3 , further comprising a support plate coupled to the first member, wherein the follower and biasing means are mounted on the support plate to confront the second member contoured surface. 
   
   
       6 . The swivel of  claim 5 , further comprising a second support plate coupled to the first member at a position spaced from the first support plate, the second support plate supporting a second follower and biasing means mounted on the second support plate to confront the second member contoured surface. 
   
   
       7 . The swivel of  claim 3 , further comprising a second follower coupled to the first member and biasing means biasing the second follower into contact with the second member contoured surface. 
   
   
       8 . A shelf unit and swivel for supporting a shelf unit for rotation with respect to an underlying base, the combination comprising:
 a shelf having an upper surface, a lower surface, and an aperture extending through the shelf between the upper and lower surfaces,   a first swivel member including a plurality of openings to receive fasteners for securing the first member to an underlying base,   a second swivel member coupled to the first member for rotation about a vertical axis, the second member being mounted to the shelf lower surface so that the shelf aperture can be aligned serially with the plurality of openings in the first swivel member, and   at least one projection projecting from a lower surface of the first member for engagement with the underlying base to facilitate a desired alignment of the first member relative to the underlying base.   
   
   
       9 . The combination of  claim 8 , wherein the first swivel member includes an outwardly facing race surface, the second swivel member includes an inwardly facing race surface confronting the first swivel member race surface, and further comprising low friction members situated between the race surfaces. 
   
   
       10 . The combination of  claim 9 , wherein the at least one projection comprises a pair of projections straddling one of the plurality of openings in the first swivel member. 
   
   
       11 . The combination of  claim 10 , wherein the second swivel member has a contoured surface including at least one pair of adjacent lobes separated by an indentation, a follower is coupled to the first swivel member, and biasing means biases the follower into contact with the second member contoured surface. 
   
   
       12 . The combination of  claim 11 , wherein the shelf is secured to the second swivel member such that the shelf aperture is aligned with an opening adjacent to the indentation between the pair of adjacent lobes when the follower is in contact with the indentation between the pair of adjacent lobes on the contoured surface. 
   
   
       13 . The combination of  claim 12 , wherein the contoured surface is situated on a radial outside surface of the second member relative to said vertical axis. 
   
   
       14 . The combination of  claim 12 , further comprising a support plate coupled to the first swivel member, wherein the follower and biasing means are mounted on the support plate to confront the second swivel member contoured surface. 
   
   
       15 . The combination of  claim 14 , wherein the follower comprises an arm pivotally mounted to the support plate, the arm having a wedge surface suitable for insertion into the indentation between the pair of adjacent lobes on the second member contoured surface. 
   
   
       16 . The combination of  claim 15 , wherein the biasing means comprises a compression spring situated between a surface of the arm obverse to the wedge surface and an upstanding flange on the support plate. 
   
   
       17 . The combination of  claim 14 , further comprising a second support plate coupled to the first swivel member at a position spaced from the first support plate, the second support plate supporting a second follower and biasing means mounted on the second support plate to confront the second swivel member contoured surface. 
   
   
       18 . A method for installing a shelf unit for rotation with respect to an underlying base, the method comprising:
 providing a swivel unit including a first swivel member including a plurality of openings to receive fasteners for securing the first swivel member to an underlying base, at least one projection projecting from a lower surface of the first swivel member for engagement with the underlying base, and a second swivel member coupled to the first swivel member for rotation about a vertical axis,   securing the second swivel member to a lower surface of a shelf so that an aperture through the shelf can be aligned serially with the plurality of openings in the first swivel member,   positioning the shelf and swivel member on the underlying base at a desired location with the aperture through the shelf aligned with one of the plurality of openings in the first swivel member,   inserting a first fastener through the shelf aperture and aligned first swivel member opening into engagement with the underlying base with sufficient force to embed the at least one projection in the underlying base,   rotating the shelf to expose another of the plurality of openings in the first swivel member,   and inserting another fastener through the shelf aperture and exposed first swivel member opening into engagement with the underlying base.   
   
   
       19 . The method of  claim 18 , further comprising repeating the last two steps until fasteners are engaged in all of the plurality of openings in the first swivel member. 
   
   
       20 . The method of  claim 18 , further comprising providing a pair of projections projecting from a lower surface of the first swivel member for engagement with the underlying base, the pair of projections straddling an opening opposite the opening into which the first fastener is engaged.