This clamping device is intended for releasably connecting two profiled parts (1,19). One of the profiled parts (1) is arranged so that an insert core (2) can be inserted and fixed in it. The core (2) has an axially movable bolt (7) having an end portion which comprises a projection (21) intended to be introduced in a slot of a second profiled part (19) in order to exert a force against an area of a portion of said second profiled part (19) partially covering said opening. A screw received in a threaded bush (4) engages the bolt (7) by means of a system of sliding surfaces (14,15) in order to displace the bolt axially. The bolt (7) has supporting means (27,28) for pivotally supporting holding pieces (17,17'). Said holding pieces and the interior walls of the insert core (2) have a second system of sliding surfaces (24,26) which owing to the axial movement of the bolt (7) cause a deviation of the holding pieces (17) having in its free end area said projection (21) intended to exert said force. Preferably, the thread of the screw (5) and the threaded bush (4) have a pitch of more than 1 mm per revolution, and preferably, the bolt (7) is led through a laterally expanded transverse hole of a threaded bush (4), and a transverse bore of the insert core (2) and the threaded bush (4) guided in it are designed in such a formlocking way that a lateral displacement of the threaded bush (4) along the transverse bore of the insert core (2) is possible.

A connector releasably connects two building elements (6, 7), one (7) of which has an engageable edge (8) and the other (6) has, at the connection end, a cavity (9). In the cavity, a first sleeve (2) of the same cross-sectional shape as the cavity is insertable therein. The sleeve has a longitudinal hole (10) for receiving an elongate clamping member (1) which includes, at its outer end, a hook (18) for engagement with the engageable edge. The part of the clamping member received in the longitudinal hole has a bevelled surface (16) to cooperate with a clamping screw (4) which, when turned, is movable transversely of the clamping member to a position with its tip against the bevelled surface under spring bias between the first sleeve and the clamping member. The bevelled surface (16) is arranged in a transverse recess (15) in the clamping member (1). Into this recess, a second sleeve (3) having a threaded hole (14) for receiving the clamping screw (4) can be depressed, against the spring bias, to a position in which the second sleeve (3) is located completely inside the circumference of the first sleeve (2).

A connecting element for the releasable connection of two structural parts of a stand, in particular a support section and a frame section, includes a housing and at least one locking element. An eccentric is rotatably supported in the housing locking element is guided longitudinally in the housing and has a clamping portion protruding from the housing to be introduced in an undercut groove of the support section and clamped therein. An eccentric head (76) of the may be locked in a bore hole of the frame section. The clamping portion of the locking element may be rotated within a limited angular range. The locking element is connected displaceably by a pulling element with the eccentric the clamping portion is a transverse bar.

Device for assembling the framework of a temporary exhibition stand; characterized in that the uprights (8) comprise at their top ends longitudinal slots (8.sub.3) situated in the bottom of dovetailed grooves (8.sub.1), the said slots (8.sub.3) terminating at the top end of the uprights which is adjacent the end of the top cross-member which is to be assembled and in that a hub (19) is disposed in these slots, the hub comprising at least one heel (22) disposed transversely in a dovetailed groove (8.sub.1), at least one ball (29) maintained in an orifice in the hub in such a way as to project into the dovetailed groove above the heel and also comprising a rod (25) sliding in the hub against the action of a spring (28), the said rod being provided with a notch (26) and being capable of assuming two positions, in one of which the notch (26) in the rod (25) is situated at the level of the ball (29) and allows it to be released from the groove to allow passage of the bolt (7), while in the other position, the rod (25) locks the ball (29) in a position in which it projects into the groove (8.sub.1) maintaining the bolt either in a high position, above the ball, or in a low position, between the heel and the ball.

A coupling member, for coupling profile bars having longitudinal grooves covered by profile walls so that a first profile bar is butt-jointed to a side wall of a second profile bar. The coupling member is inserted into the grooves aligned in one plane. The coupling includes an elongated counter holder insertable into the longitudinal groove of the first profile bar, and a tension tie incorporating a shaped head that is insertable into the longitudinal groove of the second profile bar and engages the profile walls from behind, and a shaft connected to the counter holder. The counter holder is rotatable on the tension tie by a pivot that engages the profile walls and is provided on one side with a tooth system that penetrates the groove bottom when the coupling member is tightened by rotating the counter holder.