Support member having a locking cam

Abstract

A support member or fixture of the type adapted to be removably affixed to a multi-apertured panel is formed with a generally hook-shaped projection extending from a base member adapted to engage the surface of the panel. The hook shaped projection is shaped to engage the backside of the panel in the mounted position. A rotatable shaft extends through the base member, spaced from the hook shaped projection, and forms part of a second projection adapted to be fit into another hole of the panel. The end of the shaft adapted to extend into the panel is provided with a locking cam, and the other end of the shaft, which extends from the base member side opposite the panel, is provided with means permitting the rotation of the shaft and hence the cam. When the support member is mounted on a thin panel, the cam is adapted to engage the backside of the panel and one angular position thereof. When the support member is mounted on a relatively thick panel, the cam on the shaft engages the side of the hole in the panel into which it is fit. The support member may be cast or molded with a base member and hook shaped projection forming one casting and the shaft, cam and shaft turning means forming a second casting.

Description

This invention relates to support members of the type adapted to be fit on multi-apertured panels, such as panels having rows and columns of equally spaced holes. The invention is particularly directed to a support member of the type in which means are provided for securely locking the support member to a panel.

The concept of mounting various articles on a multi-apertured panel is well known. Such panels are generally provided with rows and columns of holes, with the spacings between the holes in the columns and rows being substantially equal. The supporting members have generally consisted of bent wire members having a first portion adapted to lie against the surface of the panel, with one end of the member being bent so that it fits through a hole in the panel and engages the backside of the panel. Suitable projections are provided on the member, extending away from the panel, to permit the hanging, clamping, fastening, etc. thereon or insertion therein of articles. This type of support member has found wide acceptance in industrial, commercial and home applications.

In order to more firmly affix the support member to the panel, it has also been common to provide either a plurality of hook shaped projections for engagement with holes in a common row of the panel, or to provide an additional straight projection for engagement with a lower hole in the column of holes into which the single hook shaped projection is fitted. By this means, for example, rotation of the support member about the axis of a single hole in the board is inhibited. In order to further stabilize the position of the support member, it has been suggested that the dimensions of the parts of the support member be closely controlled, for example the spacing between hole engaging projections on the support member as well as the diameters of the projections of the support member which fit into the holes in the panel. This expedient has not been found to be generally useful, however, since the wide tolerances in the dimensions of available panels has prevented the design of a support member with close tolerances that is useable to the best advantage on any available panel. Thus, a support member which is designed to be well held in one panel, by proper design of the spacings between the projections and/or the diameters of the projections, may not fit at all in some panels, and may be only loosely fitted in other panels. In addition, the support members are generally susceptible to accidental dislodgement due to forces applied thereto in some directions, since they are insertable and removable by a simple pivotable movement about their upper hook shaped projections. The possibility of such accidental removal is of course increased with usage of a panel, since the panels are generally of a soft material subject to wear, and hence enlargement of the holes upon repeated insertion and removal of the support members.

The problem of providing a suitable support member is further compounded by the fact that boards of several thicknesses are generally available, the apertures in the boards having different diameters. While some support members have been designed for use with panels of different thickness, most support members can only be used with a panel of one thickness.

A further disadvantage of prior support members resides in the fact that, as above stated, they are generally formed as bent wire members. Such design does not readily lend itself to a pleasing appearance, and hence in the past the support members have generally appeared as purely utilitarian objects. This has of course limited the application of the support members and the multi-apertured panels to locations where design and appearance is only of minor importance.

Briefly stated, in accordance with the present invention, an improved support member adaptable for use with a multi-apertured panel is provided comprised of a base member having an upper hook shaped projection adapted to be fitted into a hole of a multi-apertured panel. One or more suitable article holding projections are also provided extending from the base member. A further projection is provided extending from the base member and adapted to be fitted into another hole of the panel. This latter projection is in the form of a shaft extending through the base member and having shaft turning means, such as a handle, on the end thereof extending away from the panel. The end of the shaft extending into the panel is provided with a cam. The cam is spaced from the surface of the base member, and is shaped so that it either can engage the backside of the panel in one angular displacement of the shaft, or can firmly engage the sides of the hole of the panel at a particular angular displacement of the shaft. For example, the cam and shaft may be designed so that when the support member is employed with a panel of a given nominal thickness the cam engages the backside of the panel, while when the support member is mounted on a panel of greater nominal thickness the cam firmly engages the side of a hole of the panel.

According to a particularly advantageous embodiment of the invention, both from the standpoint of appearance and economy of fabrication, the support member may be formed by a die casting technique, so that the base member, hook shaped projection and article supporting projections are formed as one casting, and the shaft, cam and shaft turning means are formed as a second casting extending through an aperture formed in the base member.

In order that the invention will be more clearly understood, it will now be disclosed in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of one embodiment of a support member in accordance with the present invention;

FIG. 2 is a side view of the support member of FIG. 1;

FIG. 3 is a front view of the support member of FIG. 2;

FIG. 4 is a top view of the support member of FIG. 2;

FIG. 5 is a cross sectional view of the support member of FIG. 2 taken along the lines 5--5;

FIG. 6 is an enlarged partially cross sectional view of a portion of the support member of FIG. 2, illustrating the construction of the lower projection thereof in greater detail;

FIG. 7 is a cross sectional view of the arrangement of FIG. 6 taken along the lines 7--7;

FIG. 8 is a side view of a support member in accordance with the invention illustrated in an initial stage of mounting on a panel of one thickness;

FIG. 9 is an illustration corresponding to FIG. 8 with the support member locked in position on the panel;

FIG. 10 is a view of a support member corresponding to FIG. 8, but in combination with a panel of greater thickness;

FIG. 11 is a view corresponding to FIG. 10, with the support member firmly locked to the panel of greater thickness;

FIG. 12 is an illustration of a modification of a cam which may be employed in the support member of the invention;

FIG. 13 is a cross sectional view of the cam of FIG. 12 taken along the lines 13--13;

FIG. 14 is a partially cross sectional view of a portion of a modification of a support member in accordance with the invention illustrating a support projection on the base member for the shaft; and

FIG. 15 is a cross sectional view of the support member of FIG. 14 taken along the lines 15--15.

Referring now to the drawings, and more particularly to FIGS. 1-5, therein is illustrated one embodiment of a support member 20 in accordance with the invention. The support member is comprised of a base 21. The base 21 has a surface adapted to conform to the shape of the surface of a panel. Thus, in the usual case the surface 22 is flat. An article supporting projection 23 is provided extending from the surface of the base 21 opposite the surface 22. In the illustrations of FIGS. 1-5, the projection is shown as being generally straight and inclined upwardly from the base. It will be obvious of course, that the invention is not limited to this feature, and article supporting projections may be employed of any conventional form, for supporting, retaining or holding members in any conventional manner. Thus, the projection may be hook shaped or ring shaped, clamp shaped, threaded, etc., as well as having a shape designed to conform to any given article to be suspended therefrom, or supported thereby.

An upper projection 24 is provided extending from the surface 22 of the base member in the upper portion thereof. This projection is preferably generally hook shaped, the end thereof away from the surface 22 thereby extending upwardly. The projection 24 has a cross section which enables it to be inserted in a mounting hole of a panel, preferably so that the upper surface of the projection engages the back upper edge of the mounting hole or the back of the panel above the mounting hole, and at least the bottom portion of the projection adjacent the surface 22 can engage the lower side of the mounting hole. The specific configuration of the projection and the function thereof will be described in greater detail in the following paragraphs. Since the holes in a mounting panel generally extend transversely of the surface of the mounting panel, the projection 24 preferably extends generally in a plane extending in the lengthwise direction of the base 21 and normal to the surface 22.

Referring now to FIGS. 2 and 6, an aperture 30 is provided extending through the lower portion of the base 21, spaced from the projection 24 and extending through the surface 22 and the surface 31 opposite thereof. The axis of the aperture 30 is preferably normal to the surface 22 since, as above stated, the holes in mounting panels are usually normal to the surfaces of such panels.

A shaft 32 is rotatably fitted in the aperture 30, for rotation therein, the surface of the shaft thus conforming generally to the shape of the aperture 30 so that the aperture 30 serves as a bearing for the shaft to permit primarily only rotation movement of the shaft, although as will be discussed in the following paragraphs a slight axial freedom may be permitted. A suitable knob or handle 33 is connected to the end of the shaft extending from the surface 31, to permit manual rotation of the shaft. The end of the shaft 32 which extends beyond the surface 22 preferably has a generally cylindrical portion 34 extending a determined distance from the surface 22, and a cam member 35 is provided on the end of the cylindrical portion 34.

The cam 35, which appears more clearly in FIGS. 6 and 7, may have a generally round cross section offset from the axis of the cylindrical portion 34, with the outer end 36 of the cam being generally round as illustrated in FIG. 6, if desired. The round shape of the end 36 is not, however, necessary. As illustrated in FIGS. 6 and 7, it is preferred that one edge of the cam be formed as an extension, in the axial direction, of the cylindrical portion 34. In other words, the offset of the cam is preferably such that, with the handle 33 extending in the downward direction, the upper edge of the cam is at the same level as the upper edge of the cylindrical portion 34.

In the embodiment of the invention illustrated in FIGS. 6 and 7, the cam is provided with a sharp radially extending edge 37. This sharp edge is most prominent at the circumferential edge of the cam most remote from the axis of the cylindrical portion 34, and may, as illustrated, be generally tapered into the surface of the cam so that it does not appear at the circumferential surface of the cam that lies closest to the axis of the cylindrical portion 34. As further illustrated in FIG. 6, the inner surface 38 of the cam 35, i.e., the surface toward the surface 22 of the base, preferably extends generally away from the surface 22 at the edge 37. The surface 38 is not necessarily flat, and may be generally inclined to the surface 22 as illustrated.

The support member 20 in accordance with the invention is readily adaptable to formation by a die casting technique, such as described for example, in U.S. Pat. No. 2,819,494, Morin. Briefly, in accordance with this casting process, an articulated member is formed by casting a first element with a bearing surface formed therein, and then casting a second element of the articulated member with the bearing surface of the first element serving as part of the mold for the second element. The support member of the present invention can be readily and economically formed by this process, for example by first casting a unitary element including the base 21, article holding projection 23 and hook shaped projection 24. This first casting also has the aperture 30 formed therein. Then, using the aperture 30 as part of a mold for a second casting operation, the shaft 32, cam 35 and handle 33 are cast as a unitary element. Since the support member of the invention is readily adaptable to such casting processes, it is apparent that it may be readily formed in any desired shape, the shape enabling consideration of both utilitarian and design features. Alternatively, the cam, shaft and handle may be cast first, with the shaft serving as a core for later casting of the base and fixed projections.

When a die casting technique is employed for forming the support member, it is preferred that the aperture 30 be tapered. For example, as illustrated in FIG. 6, the end of the aperture 30 toward the surface 22 has a smaller diameter than the other end of the aperture. The shaft 32 is also tapered, the tapered portion thereof extending a short distance beyond the surface 22, and the cylindrical portion 34 having a diameter slightly greater than the adjoining least diameter end of the tapered portion. When an articulated member is cast, for example by the die casting technique, there is a tendency for binding to occur at the joint. This binding can be relieved, in accordance with the present invention, when the aperture 30 is tapered as illustrated in FIG. 6, by lightly tapping or rotating the shaft to separate the tapered portion of the shaft from the tapered aperture. This technique enables free rotation of the shaft. The cylindrical portion 34 may have a slightly larger diameter than the tapered portion in order to inhibit axial movement of the shaft to an extent greater than desired. While the aperture and shaft as illustrated in FIG. 6 are tapered outwardly from the surface 22, it is apparent that a taper in the opposite direction may alternately be employed for the same purpose.

When a casting technique, such as a die casting process is employed for formation of the support member in accordance with the invention, a suitable die casting material, such as a zince die casting material or a plastic molding material may be employed for both of the cast elements of the support member. As discussed above, multi-apertured mounting panels are available in a number of thicknesses. Most commonly, the panels are available in thicknesses of approximately 1/8 and 1/4 inch. The spacing between the holes in the rows and columns of both boards of this type is generally about 1 inch. The hole diameters of the 1/8 inch thick panels is generally about 3/16 inch, and the hole diameters of the 1/4 inch thick panels are generally about 9/32 inch.

The adaptability of the support member of the invention for use on panels of both such thicknesses will now be described.

FIG. 8 illustrates an initial shape of installation of the support member 20 on the thinnest panel for which the support member is designed, i.e., a panel 40 having a nominal thickness of about 1/8 inch. The panel has an upper hole 41 and a lower hole 42, the nominal distance between the center lines of these holes being about 1 inch. The support member 20 is installed by first inserting the projection 24 in the hole 41, with a generally pivotal movement about this hole, until the surface 22 of the support member engages the front surface 43 of the panel. In order to enable such mounting, the cam 35 must be rotated by means of the handle 33 so that the cam is generally aligned with the lower hole 42, to permit the cam to extend into and through the hole 42. It is thus apparent that the diameter of the cam 35 must be no greater than the diameter of the hole 42 of the smaller thickness panel, the diameter of the cam 35 being preferably slightly less than the diameter of the hole 42 to enable free insertion of the cam 35 through the hole 42.

In the preferred embodiment of the invention, as illustrated in FIG. 8, the bottom edge 45 of the projection 24, which engages the bottom of the hole 41, is spaced from the most remote surface of the cylindrical portion 34 a distance slightly less than the nominal distance between the holes 41 and 42, so that a small spacing 46 is provided between the bottom of the hole 42 and the bottom of the cylindrical portion 34. This enables free insertion of the cam 35, and also provides tolerance for use of the support members of the invention on panels in which the dimensions are not closely controlled. The upper surface of the projection 24 has an upwardly inclined portion 47 positioned to engage the back surface of the panel 40 above the hole 41, or the upper rear edge of the hole 41 as illustrated in FIG. 8, so that the upper projection firmly holds the support member to the panel 40 against movement in a direction normal to the surface of the panel.

In order to lock the support member in position on the panel 40, as illustrated in FIG. 9, the handle 33 is rotated 180.degree. from the position illustrated in FIG. 8, to that as shown in FIG. 9, the surface 38 of the cam extends into engagement with the rear of the panel 40 just below the hole 42. The generally inclined disposition of the surface 38 facilitates this movement, and the cam may be dimensioned so that the panel is snugly wedged between the surface 38 and the surface 22. It is thus apparent that the support member 20 is now firmly locked in position on the panel 40, and cannot be accidentally dislodged by simple mechanical forces thereon.

It is of course apparent that, alternatively, the support member may be arranted so that the locking action is effected with the cam in a direction opposite to that illustrated in FIG. 9, so that the surface 38 would engage the back surface of the panel 40 above the hole 42. In this case, the support member is dimensioned so that the distance between the bottom edge 45 of the projection 24 and the upper surface of the cylindrical member 34 would permit slight clearance between the top of the hole 42 and the cylindrical portion 34. This arrangement is not preferred, however, since it does not readily adapt the support member for use on panels of other thickness, because the dimensions in this case are dependent upon the distances between the closest edges of holes, which differ in boards of different thicknesses, rather than upon the nominal distances between the axes of the holes which are the same for panels of different thicknesses, as in the arrangement illustrated in FIGS. 8 and 9.

FIG. 10 illustrates the initial step of inserting the support member 20 in a panel 50 of greater nominal thickness than that of FIG. 8, i.e., approximately one-fourth inch in thickness. The panel 50 has an upper hole 51 and a lower hole 52 with the same center line spacing as in the panel 40, but the diameters of the holes are greater than in the panel 40. The initial step of insertion, as illustrated in FIG. 10, is the same as that illustrated in FIG. 8. It is to be noted that, since the distances between the lower sides of the holes 51 and 52 are nominally the same as the distances between the lower sides of the holes 41 and 42 in the thinner panel, a spacing 56 occurs between the cylindrical portion 34 and the bottom of the hole 52, to permit easy insertion of the cam in the hole 52. Further, since the hole 52 has a larger diameter than the hole 42, the diameter of the hole 52 is more than adequate to readily receive the cam 35. It is to be noted also that the cam 35 does not extend through the back side of the panel 50, so that its circumferential portion that is the greatest distance from the axis of the cylindrical portion 34 is within the hole 52. In other words, the pointed edge 37 is within the hole 52. The projection 24 is provided with a further inclined surface 57 positioned to engage either the back side of the panel 50 above the hole 51, or the upper rear side of the hole 51, to inhibit movement of the support member away from the surface of the panel 50.

FIG. 11 illustrates the locking action of the cam 35 upon rotation of the handle 33, when the support member 20 is employed on the thicker panel. This figure illustrates that the sharp projection or edge 37, upon turning of the handle 33, now bites into the material at the bottom or side of the hole 52 to firmly wedge the material of the panel 50 in this region between the surface 38 and the surface 22 of the support member. The support member is thus firmly locked in position on the panel, and cannot be dislodged by any simple mechanical forces that would be normally expected.

It is thus apparent that the support member of the present invention is readily insertable on multi-apertured panels of different dimensions, is readily fabricated, and can be designed to have a pleasing appearance. Further, the support member can be firmly locked against dislodgement, the locking action being effective regardless of the thickness of the panel. In addition, the support member does not depend upon critical dimensioning of the elements thereof, so that its advantageous features are utilizable even though the dimensions of the mounting panels are not closely held.

In a further embodiment of the invention, as illustrated in FIGS. 12 and 13, the cam 35 may if desired be generally hemispherical, without the sharp edge provided in the cam of FIG. 6. When such a cam is employed on the support member, the cam does not bite into the sides of the holes of the thicker board, as illustrated in FIG. 11, but since the material of such boards is relatively soft, the cam can still compress the material in the hole of the panel to ensure a firm locking action. It will of course be apparent that other shapes of cams may be employed.

In a further modification of the invention, as illustrated in FIGS. 14 and 15, a projection 53 is provided on the back side of the base member, the projection engaging the top surface of the cylindrical portion 34. When the support member in accordance with the invention is fabricated from a die casting or plastic molding material, the possibility arises that the forces exerted on the cam may deform or cause the breakage of the shaft 32. The projection 53 is provided to ensure that such forces do not effect the breakage of the shaft 32. As illustrated more clearly in FIG. 15, the lower surface of the projection 53 may be arcuate to conform to the upper surface of the cylindrical portion 34, for example to an arc of about 120.degree.. The projection 53 thus provides a backup for the cylindrical portion 34 in the positions of the cam when forces are exerted thereon. The projection 34 53 of course be omitted if the strength of the materials of the support member are sufficient to withstand such forces without breakage.

As discussed above, the surface 38 of the cam 35 extends at an angle to the surface 22. This angle, which is preferably about 15.degree., provides the additional advantage that the surface 38 forms the wedging action against the back of the panel when the support member in accordance with the invention is employed in combination with a 1/8 inch panel.

It will of course be apparent that the projection 24 may be of other conventional shapes than that disclosed herein.

While the invention has been disclosed and described with reference to a limited number of embodiments, it will be apparent that many variations and modifications may be made therein, and it is intended in the following claims to cover each such modification and variation as falls within the true spirit and scope of the disclosed invention.

Claims

What is claimed is:

1. A support member adapted for mounting on a multi-apertured panel, comprising a base member having a flat surface, article holding means extending from said base member on a side thereof away from said flat surface and spaced from one end of said base member, a projection extending from said flat surface, an aperture extending through said base member to said flat surface and spaced from said projection in a direction away from said one end of said base member, a shaft rotatably mounted in said aperture, whereby one end of said shaft extends beyond said flat surface and the other end extends beyond said other surface of the base member, cam means on said one end of said shaft, said cam means having a substantially round cross-section in a plane normal to the axis of said shaft that is offset in one direction with respect to the axis of the shaft, a sharp radially extending circumferential edge on the portion thereof at the greatest distance from the shaft, and manually operable handle means on the other end of said shaft, said cam means having a surface toward said flat surface that is inclined with respect to said flat surface for wedging a panel upon which said support member is mounted between said flat surface and the inclined surface of said cam means upon rotation of said shaft.

2. In a support member adapted to be mounted on a multi-apertured panel, the member being of the type having an article supporting projection adapted to extend away from the panel in the mounted position of the member, a first hook shaped projection adapted to be fitted into a hole in the panel and engage the back side thereof, and a second projection adapted to fit into another hole of the panel; the improvement wherein said second projection comprises a shaft rotatably mounted in said support member, a cam on the end of said shaft adapted to extend into said other hole of said panel, said cam being radially offset with respect to said shaft in one direction and a manually operable handle on the other end of said shaft and extending transversely thereof in the direction parallel to the direction of offset between the cam and shaft, said cam having a substantially round cross-section normal to the axis of said shaft and a sharp radially extending edge in the direction of the offset thereof, whereby said support member can be locked in said mounted position by rotation of said handle to cause said cam to engage said panel.

3. In a support member adapted to be mounted on a multi-apertured panel, the member being of the type having a base member adapted to engage a front surface of the panel, an article supporting projection extending from said base member in a direction away from the panel in the mounted position of the support member, a hook shaped projection extending from the base member and adapted to be fit into a hole in the panel and engage the back side thereof, and a second projection extending from the base member and adapted to be fit into another hole of the panel; the improvement wherein said base member has a first surface positioned to engage the surface of the panel in the mounted position thereof, said hook shaped projection extending from said first surface, an aperture extending through said base member at its first surface, and wherein said second projection comprises a rotatable shaft extending through said aperture, a cam on the end fo said shaft which extends from said first surface, said cam being spaced from said first surface, and shaft turning means on the other end of said shaft, said cam being radially offset in one direction with respect to the axis of said shaft and having a sharp radially extending edge in said one direction and a surface toward said first surface that is inclined with respect to said first surface.

4. The support member of claim 3 wherein said aperture is tapered, and the portion of said shaft extending in said aperture has a taper matching the taper of said aperture.

5. The support member of claim 3 wherein said shaft has a cylindrical portion between said first surface and said cam.

6. The support member of claim 3 wherein said first surface is flat.

7. The support member of claim 3 wherein said cam has a substantially circular cross section, the axis of the cross section of said cam being offset from the axis of said shaft.

8. The support member or claim 7 wherein said sharp edge is formed on the circumferential surface of the circular cross-section of said cam which lies at the greatest distance from the axis of said shaft.

9. The support member of claim 3 wherein said shaft turning means comprises a manually operable handle.

10. The support member of claim 3 wherein said base member, hook shaped projection and article supporting projection comprise a first unitary cast member, and said shaft, cam and shaft turning means comprise a second unitary cast member.

11. The support member of claim 3 for use on panels of different nominal thicknesses, wherein said hook shaped projection has a first surface for engaging the back side of a panel of a first nominal thickness, and a second surface positioned to engage a back surface of a panel of greater nominal thickness.

12. The support member of claim 11 wherein the dimension between the edge of said hook shaped projection toward said shaft and the most remote edge of said shaft is less than the nominal center line distances between adjacent apertures of said panels, and the diameter of said cam is less than the diameter of a hole in the panel of lesser nominal thickness.

13. The support member of claim 12 wherein the distance between said inclined surface of said cam and said first surface of said base member is substantially equal to the thickness of said panel of lesser thickness.

14. The support member of claim 13 wherein said sharp edge is on the circumference of said cam at a position most radially remote from the axis of said shaft, said sharp edge being spaced from said first surface a distance less than the thickness of said panel of greater thickness.

15. A support member adapted to be mounted on the surface of a panel of the type having a plurality of holes extending therethrough, said support member comprising a base member having a first surface conforming in shape to the surface of said panel and a second surface opposite said first surface, article supporting means extending from said second surface, a projection extending from said surface and having a shape permitting its insertion into a hole of said panel with said first surface abutting the surface of the panel, a shaft rotatably mounted in said base member and extending between said first and second surfaces, means for rotating said shaft mounted on the end thereof at said second surface, and a cam on the other end of said shaft and spaced from said first surface, said shaft being spaced from said projection a distance corresponding to the center line distance between holes in said panel, said cam being radially offset in one direction with respect to the axis of said shaft and having a substantially round cross-section normal to the axis of the shaft with a circumferentially extending sharp edge in the region of greatest distance from the shaft, said cam being axially movable in one hole of said panel at one angular displacement thereof with the projection inserted in another hole of the panel, and being inhibited from axial movement at another angular position.

16. The support member of claim 15 wherein said projection has a length greater than the thickness of said panel, the end of said projection away from said first surface extending in a direction away from said shaft.

17. A cast support member adapted to be mounted on a panel of the type having rows and columns of equally spaced apart holes, said support member comprising: a first cast member having a body with a flat surface, a hook shaped projection extending from said flat surface, an article supporting projection extending from another surface of said body, and a hole extending through the body normal to the flat surface thereof and spaced from said hook shaped projection; and a second cast member comprised of a shaft extending through said hole, a shaft turning member on the end of said shaft at the other surface of said body, and a cam on the other end of the shaft and spaced from said flat surface, said cam having a rounded end with a substantially round cross-section normal to the axis of said shaft that is offset in one direction with respect to the axis of the shaft, a sharp radially extending circumferential edge on the portion thereof at the greatest distance from the shaft, and a surface toward said flat surface that is inclined with respect to said flat surface for wedging a panel between the flat surface and inclined surface upon rotation of said shaft.

18. The support member of claim 17 wherein said hole is tapered, the portion of said shaft in said hole being tapered to conform to the tapered shape of said hole.

19. The support member of claim 18 wherein the smaller diameter end of said hole is at said flat surface.

20. The support member of claim 3 wherein the edge of said cam in the direction thereof opposite said one direction constitutes an axial extension of said shaft.

21. The support member of claim 3 further comprising a third projection extending from said first surface adjacent said aperture and between said aperture and said hook shaped projection, said third projection having an arcuate surface engaging said shaft only on the side thereof toward said hook shaped projection, said third projection extending a distance from said aperture and parallel to said first surface that is no greater than the offset of said cam.

22. The support member of claim 3 wherein said first surface is substantially wider in the direction normal to the direction between said aperture and said hook shaped projection than the thickness of said hook shaped projection.