Untitled record

It is known in a large screen, z. As garden or market umbrella, thereby shortening the path of the screen slide that the slider is pushed when relaxing the screen instead towards the lower end of the pole in the direction of the screen crown. As a result of this shortening of the slide path, the force needed to clamp the screen when sliding the slider and also the force required to decelerate the slider sliding on the pole when relaxing the screen must be particularly great. In addition, since in a large screen pushed up against the screen crown slider is no longer reachable by hand, it is necessary to effect the displacement of the slider by means of special arranged on the lower part of the tool.

For this purpose, screw devices have primarily been used, but they still require a too large number of revolutions in the case of the still large length of the slide path, and these are too costly to produce, especially when a spindle is used.

Therefore, it was considered to cause the displacement of the slider instead of by a screw device by a lever arm device, in which the lever arm was pivoted by approximately 180 °. But since the strength of the thrust force achieved by the Hebelarmdrehung constantly changes during the pivoting of the lever arm, in this case a jerky displacement of the slide and thus when closing the screen too sudden knocking down of the heavy canopy can not be avoided.

This jerky closing of the screen is now reinforced by the fact that the slide slides in its displacement against the screen crown on the dead center, in which the pressure acting on the slider of the struts is directed perpendicular to the stick, so that when moving the slider of the large pressure the striving is only to be overcome until the achievement of the kill position, while this same pressure after exceeding the dead center position causes a displacement of the slider in the opposite direction, ie the screen crown causes and thus then makes a sudden, strong braking of the slider movement required.

Thus, the jerky occurring, their direction changing large forces of the arranged on the lower floor part, serving to move the screen slide auxiliary device can be reliably absorbed, the drive crank according to the invention is connected to a gear in a movable in the lower part of the floor, by 'a fixed Pressure member engages the screen slide hinged rack. The connection of such a per se known solid pressure transmission member with a drive device designed as a rack and pinion gearbox is particularly suitable for absorbing the sudden repulsions occurring during the transmission of the slider movement.

suitable. In addition, a rack and pinion gear has been exposed to one of the wet. Umbrella over the spindle drive the advantage that it does not rust so easily because its teeth are held stainless by use.

In the drawing, in which an embodiment of the invention is shown_a Figure I shows a longitudinal section through the frame ίο of the clamped screen, but with the canopy is limited to only two roof bars shown, Fig. 2 shows the same representation of the closed umbrella frame and Fig. 3 is a Seitenansieht one provided with teeth for forming teeth, inside the pole of the displaceable tube. There are α the pole tube, at the upper end of the roof bars b are hinged, and c the Streao ben, which are connected on the one hand with the roof bars and on the other hand with the slidable on the umbrella stick slide d. To relax the screen, the screen slide, as shown in Fig. 2, pushed against the screen crown ie. Since the slider is not reachable in this position by hand and .Also, a large force is required when mounting the large screen to pull down the slider, the serving for moving the slider special drive device is arranged at the bottom of the umbrella pole. This ordered essentially from a hand crank / and a gear g, which is to weaken the umbrella floor as little as possible, is stored in a special, attached to the floor h cage and with his ring gear through a slot located in the pole in the interior of the tube passes. In this case, the teeth engage in the toothed incisions versehen and designed as a toothed rack, which can be displaced in the "floor tube". On the pole L is a • rack tn attached, which is connected at its upper end to the slider d by a slidable in floor tube slots η bolt ο, so that by the rotation of the crank / the rack / and thus also to open and close the Screen the slider d is moved. When the screen is released, the bolt ο strikes against a pressure spring accommodated in the upper tube end; on, which still supports the pulling down of the slide when mounting the screen.