FIG. 1 is a perspective view of a first embodiment of the invention.
FIG. 2 is a side elevation view of the first embodiment.
FIG. 3 is a side elevation view, opposite the view of FIG. 2, of the first embodiment.
FIG. 4 is a side elevation view of the first embodiment.
FIG. 5 is a side elevation view, opposite the view of FIG. 4, of the first embodiment.
FIG. 6 is a top plan view of the first embodiment.
FIG. 7 is a bottom plan view of the first embodiment.
FIG. 8 is a perspective view of a second embodiment of the invention.
FIG. 9 is a side elevation view of the second embodiment.
FIG. 10 is a side elevation view, opposite the view of FIG. 9, of the second embodiment.
FIG. 11 is a side elevation view of the second embodiment.
FIG. 12 is a side elevation view, opposite the view of FIG. 11, of the second embodiment.
FIG. 13 is a top plan view of the second embodiment.
FIG. 14 is a bottom plan view of the second embodiment.
FIG. 15 is a perspective view of a third embodiment of the invention.
FIG. 16 is a side elevation view of the third embodiment.
FIG. 17 is a side elevation view, opposite the view of FIG. 16, of the third embodiment.
FIG. 18 is a side elevation view of the third embodiment.
FIG. 19 is a side elevation view, opposite the view of FIG. 18, of the third embodiment.
FIG. 20 is a top plan view of the third embodiment.
FIG. 21 is a bottom plan view of the third embodiment.
FIG. 22 is a perspective view of a fourth embodiment of the invention.
FIG. 23 is a side elevation view of the fourth embodiment.
FIG. 24 is a side elevation view, opposite the view of FIG. 23, of the fourth embodiment.
FIG. 25 is a side elevation view of the fourth embodiment.
FIG. 26 is a side elevation view, opposite the view of FIG. 25, of the fourth embodiment.
FIG. 27 is a top plan view of the fourth embodiment; and,
FIG. 28 is a bottom plan view of the fourth embodiment.
The structure shown in broken lines is for environmental purposes only and does not form any part of the claimed invention.