Blister with tilting side-walls
A blister sheet ( 1 ) has a generally rectangular blister ( 2 ) formed with one pair of longer side walls ( 7 ) having parallel steps ( 8 ) and a second pair of shorter side wall ( 9 ) devoid of steps. The side walls serve to space a front face ( 5 ) of the blister from the plane of a rupturable foil backing sheet ( 4 ) which retains medication doses (nor shown) inside the blister until they are to be taken. The medication doses are ejected from the cavity of the blister ( 2 ) by depressing its front face with finger pressure so that they are forced against the backing sheet ( 4 ) with sufficient force to rupture it. During the application of finger pressure to the front face ( 5 ) it bows downwardly in its central region as indicated by the broken outline. Simultaneously the end walls ( 9 ) tilt inwardly towards one another so that any medication doses lying against them are forced into the central region of the blister from which they can be ejected more easily by the descending front face ( 5 ).
1. A blister sheet having a planar back and provided with a blister having first and second pairs of side walls and a front face held spaced from the plane of the back of the sheet by the side walls, the blister being of elongated shape and the first pair of side walls being longer than the second pair of side walls, the first pair of side walls being so formed that they yield under finger pressure applied to the front face of the blister while progressively collapsing from the front face in response to increasing finger pressure being applied to the front face, and the second pair of side walls responding to the finger pressure by tilting towards one another so that any medication dose which may be located against a tilting side wall is displaced towards a position lying beneath the front face and from which it can be ejected by increasing finger pressure, and wherein the first pair of side walls are formed with parallel steps, and the second pair of side walls have their central regions devoid of steps or corrugations and of planar trapezoidal shape so that they can tilt towards one another about their edges where they join the portions of the blister sheet from which the associated blister protrudes.