This invention generally relates to toy building sets comprising a plurality of hollow box-shaped elements provided with engagement studs or projections of the kind specified in U.S. Pat. No. 3,005,282, and, more particularly, to a rotatable element of a similar kind as the turntable element described in U.S. Pat. No. 3,236,004, but which differs substantially from this prior art both as regards simplicity of the construction and the technical advantages afforded by the rotatable element according to the present invention.
One object of the invention is to provide a rotatable element which is suitable for mass production by injection moulding of thermoplastic or thermosetting materials.
Another object is to provide a rotatable element which comprises only two components, viz. a base plate and a disc provided with locking means of simple and inexpensive construction and which, moreover, serve as coupling means for connecting the rotatable element to adjacent elements in a toy building set of the kind referred to.
Other objects of the invention will appear from the following description of an embodiment of the invention with reference to the accompanying drawings.
In the drawings:
FIG. 1 is a plan view of the top surface of the base plate,
FIG. 2 is a plan view of the underface of the base plate,
FIG. 3 is a plan view of the upper surface of the disc,
FIG. 4. is an axial section taken on the line IV--IV of FIG. 3,
FIG. 5 is a plan view of the underface of the disc,
FIG. 6 is a plan view of the top surface of the rotatable element with the disc mounted in the base plate, and
FIG. 7 is an axial sectional view taken on the line VII--VII of FIG. 6.
In the embodiment shown in the drawings, the rotatable element comprises a square base plate 1, as shown in FIGS. 1 and 2, having an upper surface 1a and a circular aperture 2 therein adapted to receive a cylindrical disc 3, as shown in FIGS. 3, 4 and 5. The underface of the disc 3 is provided with a centrally disposed pivot 3c for pivotally mounting the disc 3 in a cylindrical bushing or socket 6 in the base plate.
The top face of the disc 3 is provided with four engagement studs 3a symmetrically disposed with respect to the centre of the disc adjacent the periphery thereof and extending beyond the periphery, so as to present bottom faces 3ax for slideable contact with the top face 1a of the base plate during the rotation of the disc.
The top faces of the engagement studs 3a may be provided with cylindrical recesses 3ay providing for saving of material during the moulding of the disc. Moreover, these recesses 3ay may also be adapted to receive coupling studs on an adjacent element pertaining to the building set, so as to provide for assembly of such elements with the disc 3.
As shown in FIGS. 4 and 5, the pivot 3c may be provided with a slit 3cy and a collar 3cx to form a snap lock for preventing axial displacement of the pivot 3c relatively to the socket in which it is pivotally mounted.
The arrangement of the socket 6 in the base plate will appear from FIGS. 1, 2 and 7.
As shown in FIG. 2, the base plate comprises a bottom face 1b which is integral with four side walls 4 defining a cavity. In this cavity, there is mounted a cylindrical bushing or socket 6 having a cylindrical bore 6z for pivotally mounting of the pivot 3c. The external cylindrical face 6y of the socket 6 is integral with four ribs 5 which are integral with the side walls 4 adjacent the middle thereof, so as to support the socket 6 in the cavity defined by said side walls. The annular bottom face of the socket is designated as 6x and is adapted to cooperate with the collar 3cx of the pivot 3c to provide for the snap locking effect, when the pivot is inserted in the bore, 6z with a slight deformation of the material owing to the slit 3cy.
As shown in FIG. 2, the bottom face 1b of the base plate together with the side walls 4, the ribs 5 and the outer cylindrical face 6y of the socket 6 define four identical sections 7 of the circular aperture 2 in the base plate, and the shape of these apertures is adapted so as to provide coupling means for clamping engagement studs on an adjacent element pertaining to the building set.
Thus, the rotatable element according to the invention provides for interrotatable connection of a pair of conventional building elements having engagement studs adapted, on the one hand, to be connected to the studs 3a on the disc 3 and, on the other hand, to be clamped in the apertures 7 of the base plate 1.