The present invention concerns shade structures like umbrellas, in particular large free-standing umbrellas. Such umbrellas are often unfolded and folded manually by pushing a slider up- and downwards the mast of the umbrella. The length of the ribs of umbrellas usually depends on the size of the canopy. If the canopy is large, the ribs are very long. This leads to the unwanted situation that a large umbrella may not be folded or unfolded next to objects like garden furniture, because the ribs would collide with such items. Further, such umbrellas cannot be placed in the middle of a table, because the tabletop would prevent a complete folding or unfolding. In addition, items placed on the tabletop could be swept away at such an attempt.
Simply extending the mast and thereby raising the top of the umbrella, where the ribs are connected, would not solve the problem. This would thus lead to a correspondingly higher position of the slider in the unfolded position of the umbrella, so that the umbrella could not be handled by persons with normal or even shorter length.
Another problem of large free standing umbrellas is that the bigger size of the canopy automatically leads to a higher weight of the ribs and/or the canopy. The unfolding and folding of the umbrella therefore becomes more difficult.
The U.S. Pat. No. 4,424,824 A discloses an umbrella having a support tube uppermost end portion into which is telescopically received an umbrella shaft carrying a crown to which is pivotally connected cover ribs, a sleeve in external telescopic relationship to the support tube, a plurality of struts pivotally connected between the sleeve and the cover ribs, a threaded spindle within the umbrella shaft threaded relative to a threaded nut fixed to the umbrella shaft, and a flexible element, such as a cable, rope or wire, having ends fixed to the sleeve and to the umbrella shaft and being guided over a pulley carried by the umbrella shaft. As a result, the procedure of opening and closing the umbrella canopy is very complex. The umbrella canopy is closed, while the umbrella shaft is extended, in others words, closing or opening the umbrella canopy and extending or retracting the umbrella shaft are working at the same time, namely the two actions are synchronous. The length of the guide tube extended outward from the support tube is very long, so the top of the closed umbrella will be very high. This is disadvantageous e.g. when storing the umbrella away, in particular under a roof or such. Also the known umbrella needs more space when closed for transport, which i.a. leads to higher costs for shipping. Additionally, in order to facilitate the opening and closing procedure, the overall operating-system of the known umbrella includes threaded means in the form of a threaded spindle supported in an undisplaceable or fixed fashion at a lower end portion by means of gear means in the form of a miter gear. This makes the fabrication of the known umbrella complicated, time consuming and costly. A more simple system for facilitating the folding and unfolding of an umbrella is known from the U.S. Pat. No. 8,087,420 B1, which discloses an umbrella system which includes a counterweight and system of pulleys, where the system of pulleys includes class 1 and class 2 pulleys configured with the counterweight to gain a mechanical advantage in the normal operation of the umbrella. This prior art, however, does not teach any solution or even discusses the problem of the long ribs at large canopies.
The underlying technical problem of the present invention is to provide an umbrella which may be operated in the vicinity of other objects or in the middle of a table even if the canopy is large and the ribs of the umbrella are long. The height of the folded umbrella shall be relatively low. The mechanism of the umbrella shall be simple and easily to be manufactured at comparably low costs. The umbrella shall to be opened and closed easily.
This technical problem is solved by an umbrella according to the present invention. An upper hub is fixed to a guide tube, but not to a support tube as at the conventional umbrellas. The guide tube is telescopically disposed in and reciprocally movable relative to a uppermost end portion of the support tube. The guide tube and a slider, sleeve or runner are interconnected by flexible traction means in the form of a flexible traction member, e.g. a rope. Preferably the traction member may be guided by pulley means in form of a pulley secured to the upper end portion of the support tube. One end of the flexible traction member is firmly secured to the slider, the other is firmly secured to a counterweight component. It is advantageous, if the flexible traction member, e.g. a rope, passes through the counterweight component in the support tube, whereas both ends of the flexible traction member are firmly secured to the slider. Preferably the weight of the counterweight is determined in a way that the counterweight supports the upward movement of the slider and thereby facilitates the opening of the umbrella.
The operation of the shade structure according to the invention is even more facilitated by a second embodiment. There is added a free pulley system in order to save some force. This pulley system consists of an additional push rod, which is disposed telescopically in the support tube and the guide tube, and which is operated by the means of an additional traction member, e.g. a rope, which is guided by additional pulleys mounted at the guide tube and the support tube. When closing the umbrella, the counterweight component actuates the push rod, which pushes the guide tube upwards. Examples for carrying out the invention are shown in the drawings and are described in detail as follows.
When closing the umbrella, the slider (3) is moved downwards the support tube (5). By this, the slider (3) pulls the flexible traction member (6), so that the counterweight component (7) connected to the flexible traction member (6) is lifted upwards. When the upper end of the counterweight component (7) comes in touch with the lower end of the guide tube (4), the guide tube (4) is pushed upwards by the counterweight component (7). By this, the upper hub (1), which is connected to the guide tube (4), is lifted. This simultaneously causes a lift of the ribs (8), pivotally connected to the upper hub (1).
The weight of the counterweight component (7) should be chosen in dependence of the size and weight of the canopy and its ribs (9a) and struts (9b). It is in general possible to dimension the weight of the counterweight component in a way, that the counterweight may automatically pull the interconnected slider upwards. If so, it may be advantageous to provide additional openings in the support tube (5), into which hooks (10) of the slider (3) may intrude in the closed position of the umbrella, in order to secure the slider in this position.
Number | Date | Country | Kind |
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16020403.8 | Oct 2016 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2017/080687 | 4/15/2017 | WO | 00 |