Expanding mechanism for a tensionable device and tensionable device

Abstract

The invention relates to a spreading mechanism (30) for a clampable device (10) and to a clampable device (10) which comprises a standpipe (12) and a clampable support frame (14) with a plurality of pairs of support arms (16) which diverge in a star shape and support struts (18) which are articulated to the support arms (16), wherein the support arms (16) are articulated to a first central support (20) and the support struts (18) are articulated to a second central support (22), and the spreading mechanism (30) is designed to clamp or close the support frame (14) by reducing or increasing the distance between the first central support (20) and the second central support (22).The spreading mechanism (30) comprises an actuating mechanism (50) and a pulley block (32) with a pulley cable (40), a fixedly attached first roller holder (34) and a movable second roller holder (36), each with one or more rollers (38) over which the pulley cable (40) is guided, wherein the actuating mechanism (50) is connected to the movable second roller holder (36) of the pulley block (32) and a fast end (42) of the pulley cable acts in a displacing manner on the first central holder (20) and / or the second central holder (22) in order to change their distance from one another.

Description

[0001] The invention relates to a spreading mechanism for an expandable device, such as a parasol or a rotary clothesline, as well as an expandable device

[0002] Rotary clotheslines and freestanding umbrellas, both center-pole and side-arm models, have very similar extendable support mechanisms. Center-pole umbrellas and rotary clotheslines are particularly similar in that they each have multiple support arms, which are centrally hinged to a bracket on the central pole or standpipe, as well as an equal number of support struts, which are hinged to the support arms and then to another bracket on the central standpipe. In the case of freestanding umbrellas, the support arms hold a canopy made of fabric or another flexible, flat material; in the case of rotary clotheslines, they hold the clotheslines.

[0003] The configuration of the support arms and struts differs between freestanding clotheslines and rotary clotheslines in that, on freestanding clotheslines, the support arms are usually attached to the top of the pole by a bracket, also called a "crown," which is fixed at the upper end of the pole. The struts are attached to a second bracket below, which is vertically movable along the pole. This is also called a sliding ring or guide sleeve. In contrast, on rotary clotheslines, the struts are typically attached to the upper, fixed bracket, and the support arms to the lower, vertically movable bracket.

[0004] In both cases, the extendable support device is deployed by pushing the lower retaining device upwards, thereby reducing the distance between the two retaining devices and moving the support arms into an extended position. In this position, the support arms are inclined downwards for parasols and upwards for rotary clotheslines.

[0005] The principle is very similar for side-arm umbrellas. However, the holding devices are not attached directly to the standpipe. Instead, a side arm branches off from the standpipe, or a curved standpipe is used, from the end of which a lateral mechanism extends, allowing the distance between the two holding devices to be adjusted.

[0006] Finally, there are also combinations of standing umbrellas and rotary clotheslines on the market, in which the umbrella is attached above the clotheslines and both parts are opened up with a mechanism, as is known, for example, from DE 10 2008 052 049 A1 or from EP 3 070 198 B1.

[0007] Various spreading mechanisms are used and known for rotary clotheslines and freestanding umbrellas. While the axially movable sliding sleeve of hand-held umbrellas and small parasols is manually moved until it reaches a locking device, rotary clotheslines or larger freestanding umbrellas, for example, use hand-operated ropes or crank-driven ropes.

[0008] There are also electric drives or pulley systems. These are used, for example, in rotary clotheslines, where the end of the pulley rope leads out of the standpipe in which the pulley is located. A long length of the pulley rope is pulled out, and with a corresponding multiplication of the required force, the lower support device, which is connected to a movable pulley holder of the pulley system, is raised a smaller amount up the standpipe, thus raising the support frame of the rotary clothesline. This is often combined with a retraction mechanism for the long end of the pulley rope, which is pulled back into the standpipe as soon as the long pulley rope is released.

[0009] Especially towards the end of the setup process, a strong lateral pull is exerted on the standpipe of the rotary clothesline, so secure anchoring in the ground or a very stable stand is necessary to prevent the clothesline from tipping over. The same applies to clothesline umbrellas operated by pulley systems.

[0010] Furthermore, DE 85 17 737 U1 discloses a standing parasol with a standpipe at the upper end of which canopy ribs, supporting a canopy, are hinged via a retaining crown. Spreader struts are hinged to the canopy ribs on one side and to a height-adjustable strut ring enclosing the standpipe on the other. The retaining crown and the strut ring are connected on the outside of the standpipe by a pulley-like cable, the first end of which is attached to the retaining crown and the second end of which is loosely attached to a locking lever designed as a pawl for the strut ring. The standing parasol is tensioned via the pulley-like cable and locked by the pawl. The locking mechanism can be released by pulling the end of the loose cable loop.

[0011] Compared to known spreading mechanisms and clamping devices, the object of the present invention is to provide a spreading mechanism and a clamping device with which the support frame can be clamped with little physical effort.

[0012] This problem is solved by a spreading mechanism for a clampable device comprising a standpipe and a clampable support frame with several star-shaped pairs of support arms and support struts articulated to the support arms, wherein the support arms are articulated to a first central support and the support struts are articulated to a second central support, and the spreading mechanism is designed to open or close the support frame by reducing or increasing the distance between the first central support and the second central support, further developed by the fact that the spreading mechanism includes an actuating mechanism and a pulley system with a pulley rope, a fixed first pulley holder and a movable second pulley holder, each with one or more pulleys over which the pulley rope is guided.wherein the actuating mechanism is connected to the movable second pulley holder of the pulley system such that actuation of the actuating mechanism causes a deflection of the movable second pulley holder, and a quick end of the pulley rope is connected to the first intermediate support or the second intermediate support such that, when the actuating mechanism is acted, it acts in a displacing manner on the intermediate support to which it is connected in order to change the distance between the intermediate supports, wherein the pulley system is arranged inside the standpipe.

[0013] The invention is based on the fundamental idea of ​​using a pulley system in the opposite direction to the usual method for spreading the supporting frame. The fast end of the pulley system, i.e., the end of the pulley rope that moves quickly and over a long distance, is no longer used to operate the pulley system, but is connected to a movable intermediate support, i.e., the sliding sleeve, while the slow end of the pulley system, i.e., a movable pulley holder, is subjected to a greater force and a smaller deflection. This is counterintuitive because the force required on the pulley system is greater than the force needed to spread the supporting frame itself. This is compensated for by the actuating mechanism connected to the movable second pulley holder. This actuating mechanism is preferably designed to exert a large force with a small deflection.

[0014] The transmission ratio of a pulley system is defined by the number of rope sections of the pulley rope running between the two pulley holders and, in embodiments, is between 2:1 and 10:1, preferably between 4:1 and 8:1. This includes both even and odd transmission ratios.

[0015] Advantageously, the spreading mechanism includes a force support device designed to continuously exert a force on the movable second pulley holder of the block and tackle, directed in the direction of extending the support structure. This supporting force then no longer needs to be applied by means of the actuating mechanism, thus facilitating the extension of the support structure. The supporting force applied by the support device should preferably be dimensioned such that it assists the extension but does not prevent the extension, which is typically assisted by gravity.

[0016] In some embodiments, the power assist device is designed as a spring assembly with a spring or a combination of springs, in particular a coil spring, gas spring and / or gas tension spring, and / or as a weight. These can be housed in the standpipe of the device. A coil spring can be used as a tension spring or as a compression spring, whereby the deflection of a tension spring represents an extension and of a compression spring a compression of the spring.

[0017] While a weight provides a constant force independent of position when used as a force-assist device, the force provided by a spring depends on its deflection. The greater the deflection of a spring, i.e., the stretching or compression, the greater the restoring force it exerts. Since a spring, regardless of whether it is a tension or compression spring, relaxes when assisting in the setup of the device's support frame and compresses again when it is released, the assisting force is smaller at the end of the setup process than at the beginning. At the same time, the spring force near the fully extended position, where it reaches its maximum, must not be so great as to impede the closing of the support frame.

[0018] In this context, when using a spring or combination of springs as a force support device, embodiments provide for a spring characteristic curve that is linear, degressive, or progressive. A degressive characteristic curve is understood to be a spring characteristic that increases less than linearly with increasing deflection. In other words, a degressive spring characteristic curve describes a spring that becomes softer with increasing load and stiffer with decreasing load. This means that the support remains comparatively high even with decreasing deflection, i.e., decreasing load, in order to continue supporting the clamping process. Preferably, the spring should still exhibit sufficient deflection even in the clamped position of the support frame. This ensures sufficient restoring force even in the more relaxed of the two end states.In contrast, a progressive spring characteristic describes a spring that becomes stiffer with increasing load and softer with decreasing load. In further embodiments, the spring assembly is combined with a weight.

[0019] In some embodiments, the actuating mechanism is rigidly connected to the movable second pulley holder of the block and tackle. This is achieved by connecting the actuating mechanism to the movable second pulley holder via a pull rope, a pull chain, or a rigid push-pull rod. The latter embodiment with the rigid push-pull rod has the additional function of allowing a force to be applied to the block and tackle via the actuating mechanism to assist with tensioning.

[0020] In various embodiments, the actuating mechanism is designed as a lever, electric winch, hand-operated rope, hand crank, foot pedal, or hand lever for a pull rope, or as a hand lever for a rigid push-pull rod. Depending on the design of the actuating mechanism, the gear ratio of the pulley system can be selected to match the force that can be applied by means of the actuating mechanism. For example, a hand-operated rope allows for a comparatively low force to be applied, which can be compensated for by a low gear ratio. A hand crank, foot pedal, or hand lever, with a sufficiently long lever arm or crank arm, allows for a significantly greater force to be applied, so that the gear ratio of the pulley system can also be chosen to be correspondingly higher.

[0021] Furthermore, a locking device for the actuating mechanism may be included, or the actuating mechanism may be self-locking. Alternatively, the support frame itself may be equipped with a locking device that holds the support frame in the extended position.

[0022] In an embodiment in which the actuating mechanism is self-locking, the lever of the actuating mechanism has a short lever arm and a long lever arm, wherein the short lever arm is connected at one end to the movable second pulley holder of the block and tackle and is pivotally connected at its other end to the long lever arm, wherein the long lever arm is pivotably attached to the standpipe about a horizontal axis of rotation at a first distance from the connection to the short lever arm, wherein the first distance and a second distance of the horizontal axis of rotation from the standpipe are selected such thatthat when the clampable support frame is opened by pivoting the long lever arm from a downward-pointing end position to an upward-pointing end position, the end of the short lever arm connected to the movable second pulley holder of the block and tackle passes through a low point and, upon reaching the upward-pointing end position of the long lever arm, assumes an end position above the low point.

[0023] The self-locking mechanism relies on the fact that, in its end position, the second pulley holder of the block and tackle is not at its lowest point, but positioned slightly above it. It requires force to move it back down to the lowest point and beyond, which gives the operating mechanism a strong tendency to remain in its end position. This can be further enhanced by a clamping mechanism that clamps and, if necessary, fixes the long lever arm in its upward-pointing end position.

[0024] The problem underlying the invention is also solved by a clampable device with a standpipe and a clampable support frame with several star-shaped pairs of support arms and support struts articulated to the support arms, wherein the support arms are articulated to a first central support and the support struts are articulated to a second central support, as well as a spreading mechanism designed to open or close the support frame by reducing or increasing the distance between the first central support and the second central support, wherein the spreading mechanism is designed according to the invention as described above.

[0025] The clampable device thus achieves the same advantages, properties and features as the spreading mechanism according to the invention.

[0026] In embodiments, the deployable device is designed as a standing screen, in particular a center-pole screen or side-arm screen, as a rotary clothesline or as a combination of a rotary clothesline and a center-pole screen.

[0027] Further features of the invention will become apparent from the description of embodiments according to the invention, together with the claims and the accompanying drawings. Embodiments according to the invention may fulfill individual features or a combination of several features.

[0028] Within the scope of the invention, features marked with "in particular" or "preferably" are to be understood as optional features.

[0029] The invention is described below, without limiting the general concept of the invention, with reference to exemplary embodiments and the drawings, whereby for all details of the invention not explained in detail in the text, explicit reference is made to the drawings. The drawings show: Fig. 1 schematic representation of a parasol in the closed and open states, Fig. 2 a schematic representation of an embodiment of a spreading mechanism according to the invention, Fig. 3 schematic representations of two embodiments of spreading mechanisms according to the invention, Fig. 4 schematic representations of embodiments of spreading mechanisms with different actuating mechanisms and Fig. 5 schematic representation of the operation of an embodiment of a spreading mechanism with a self-locking actuating mechanism.

[0030] In the drawings, identical or similar elements and / or parts are provided with the same reference numbers, so that a re-presentation is omitted.

[0031] Fig. 1 Figure 1 shows a schematic representation of a cantilever parasol as an example of a deployable device 10 in the closed and open states. The cantilever parasol has a standpipe 12, also called a mast, which (not shown) is anchored to the ground in the open state. The cantilever parasol has a standpipe 12, also called a mast, which (not shown) can be anchored to the ground or erected with a stable base. At its upper end, the cantilever parasol has a support frame 14 with a plurality of support arms 16, each of which is articulated to a support strut 18. The support arms 16, on which a canopy 17 rests, converge centrally at a first central support 20, also called a crown, where they are articulatedly suspended.Approximately in the middle of the support arms 16 are articulated connections to the support struts 18, which run from the support arms 16 in turn towards the standpipe 12, where they are articulatedly attached to a sliding second central support 22, which is also referred to as a sliding sleeve or similar.

[0032] In the folded state shown on the left, the support arms 16 hang essentially vertically from the first central support 20, which is fixedly connected to the upper end of the stand tube 12, as do the support struts 18. The distance between the first central support 20 and the movable second central support 22 is at its maximum in this state. In the unfolded state shown on the right, the support arms 16 point apart, but maintain a straight angle typical of parasols. The support arms 16 are held in the unfolded position by the support struts 36. For this purpose, the second central support 22 has been moved from its lower position to an upper position by a vertical stroke S2.

[0033] In Fig. 1 In the upper region of the standpipe 12, a spreading mechanism 30 with a pulley system 32 according to the present invention is also shown. The pulley system 32 comprises a fixedly suspended first pulley holder 34 and below it a movable second pulley holder 36, each with a plurality of pulleys 38. A pulley rope 40 runs, wound several times, over the plurality of pulleys 38 on the first pulley holder 34 and the second pulley holder 36, and is Fig. 2 This is clearly recognizable. The pulley rope 40 is connected at its fast end 42 to the movable second center support 42. The pulley system 32 is articulated such that a vertical displacement of the movable second pulley holder 36 by a stroke S1 is converted into a counter-rotating stroke S2 ​​of the fast end 42 of the pulley rope 40. In the exemplary embodiment of the Fig. 1 As in the following embodiments, the transmission ratio of sections S2 to S1 is chosen to be 8:1. Conversely, this transmission ratio also applies to the force required to erect the support frame 14, which is thus multiplied eightfold.

[0034] Fig. 2 is a schematic representation of an embodiment of a spreading mechanism according to the invention. Fig. 1 in more detail. It can be seen that the pulley system 32 is suspended by its upper first pulley holder 34 from an upper suspension point 33, while the lower second pulley holder 36 is freely movable relative to the first pulley holder 34. Both pulley holders 34 and 36 each hold four pulleys 38 of different circumferences, around which the pulley rope 40 is wound in a manner typical of a pulley system. The number of sections of the pulley rope 40 between the first pulley holder 34 and the second pulley holder 36 is eight and determines the gear ratio 8:1 of the pulley system 32. For this purpose, one end of the pulley rope 40 is attached to an upper anchor point 35, which coincides with the axis of the lowest pulley 38 of the first pulley holder 34. The pulley rope 40 is then led downwards four times to a pulley 38 of the second pulley holder 36 and back upwards to a pulley 38 of the first pulley holder 34.After the last upward guidance of the pulley rope 40, the pulley rope 34 is led into the upper suspension 33 and there via a deflection pulley 39 outwards and downwards to the movable second center support 22.

[0035] The lower second roller holder 36 also has a lower stop point 37 where a force can be applied, which can be applied by an actuating device of the spreading mechanism. As also in Fig. 2 As indicated, the 8:1 transmission ratio for the pulley 32 means that a stroke S1 of the second roller holder 36 is converted into a counter-rotating stroke S2 ​​of the second center support 22. The stroke S2 ​​is eight times the stroke S1. Conversely, the force F2 on the second center support 42 is only one-eighth of the force F1 exerted on the second roller holder 36.

[0036] Fig. 3 Figure 1 shows schematic representations of two embodiments of the spreading mechanisms according to the invention, both of which have different force support devices 90, each of which is connected, for example, attached, to the lower stop point 37 with a movable second roller holder 36 of the pulley 32. In the left-hand illustration of the Fig. 3 This is a coil spring 92, which is connected at its upper end to the second roller holder 36 and at its lower end is attached to a coil spring stop 93 on the standpipe 12. In this configuration, the coil spring 92 is a tension spring.

[0037] In the right half of the image of Fig. 3 An embodiment is shown in which the force support device 90 is a weight 94 attached to the lower stop point 37 on the second roller holder 36. The weight 94 pulls the second roller holder 36 downwards with a constant force. With the transmission ratio remaining unchanged from the previous examples at 8:1, one-eighth of the force exerted by the weight 94 is applied to the second central support 22 and is available to assist in unfolding the support frame 14. The foot pedal 66 can also be equipped with a locking device 80.

[0038] In the fourth example of the Fig. 4 The actuating mechanism 50 comprises a hand lever 68 to which the pull rope 52 is attached, approximately one-third of the way along its length from a joint on the standpipe 12 to the open end of the hand lever 68. The in Fig. 4 The support frame 14 (not shown) is tensioned by moving the hand lever 68 from its downward-pointing position, which is in Fig. 4 As shown, it is brought into an upper position. Through leverage, the movement of the outer end of the hand lever 68 is transmitted to the second roller holder 36 with a transmission ratio of approximately 3:1.

[0039] Fig. 4 The figure shows several schematic representations of embodiments of spreading mechanisms with different actuation mechanisms. In all illustrated embodiments, a force support device 90 in the form of a coil spring 92 is shown, as in the left figure. Fig. 3 available.

[0040] The embodiments of Fig. 4 The two embodiments differ in their actuation mechanisms 50. In the first embodiment, from left to right, the actuation mechanism 50 comprises a hand crank 64 around which a pull rope 52 is wound. Depending on the length of the crank arm of the hand crank 64, the spreading mechanism 30 can be operated with reasonably little effort to tension the support frame 14. The hand crank 64 can be equipped with a locking mechanism and / or be self-locking.

[0041] The second embodiment comprises a hand-operated pulley 62 deflected around a pulley 63 and a hook 65 around which a loop of the hand-operated pulley 62 can be formed. The pulley 63 makes it possible to pull the loop of the hand-operated pulley 62 upwards with a favorable lever arm, thus exerting a force on the second pulley holder 36 at a more favorable angle of attack. If the pulley 63 is located near the ground, even when pulled sideways, only a small tilting moment is exerted on the device due to the short lever arm to the ground. Because no force transmission occurs, this type of actuating mechanism 50 is particularly suitable for smaller gear ratios of the pulley 32. For locking purposes, for example, another hook 65 for the loop of the hand-operated pulley 62 can be provided further up on the standpipe 12.

[0042] The one in the middle in Fig. 4 The illustrated embodiment has a foot pedal 66 which is pivotally fixed at a pivot point 67. Approximately at the midpoint of the longitudinal extension of the foot pedal 66, a pull cable 52 or a rigid push-pull rod 54 is connected to the foot pedal 66, which, when the foot pedal 66 is pressed down, pulls the second roller holder 36 downwards. Due to the leverage ratio at the foot pedal 66, a transmission ratio of 2:1 results, which in this case means that the stroke of the open end of the foot pedal 66 is halved when the force is transmitted to the second roller holder 36, and the applied force is doubled.

[0043] The in Fig. 4 The embodiment shown on the far right is also based on the use of a hand lever 70, which, however, is equipped with a self-locking mechanism. This is in Fig. 5 schematically depicted in its function from a closed position (left) to an open and locked position (right).

[0044] In this embodiment, the hand lever 70 comprises a long lever arm 74 with a handle 75 and a short lever arm 72, which is pivotally connected to the long lever arm 74 and forms a connection between the long lever arm 74 and a rigid push-pull rod 54 inside the standpipe 12, which connects the lever arm 70 to the lower stop point 37 of the second roller holder 36, as is the case, for example, in Fig. 2 As shown, a joint 73 forms the connection between the short lever arm 72 and the push-pull rod 54. The long lever arm 74 is pivotable relative to the standpipe 12 about a horizontal pivot axis 76, which is suspended on a stop body 78 attached laterally to the outside of the standpipe 12.

[0045] Links in Fig. 5 This is the starting point for setting up the in Fig. 5 The supporting structure 14, not shown, is depicted. The long lever arm 74 points horizontally downwards. Slightly above the horizontal axis of rotation 76 of the long lever arm 74, the short lever arm 72 is hinged, which runs obliquely downwards into the standpipe 12 and is connected via the joint 73 to the tension-compression rod 54, which in this situation is in its uppermost position. This corresponds to the Fig. 1 The situation shown on the left, in which the support frame 14 is folded in.

[0046] To open the clamp, the long lever arm 74 is pivoted upwards, as shown in the three following partial images of the Fig. 5 As shown in the illustration, the end of the long lever arm 74, connected to the short lever arm 72, is deflected via the horizontal pivot axis 76 and moves downwards. Via the joint 73, it pulls the push-pull rod 54 downwards, thus pulling the second pulley holder 36 of the block and tackle 32 downwards and thereby tensioning the support frame 14. It is also evident that, due to the ratios of the lengths of the segments of the long lever arm 74 relative to the horizontal pivot axis 76, a comparatively large transmission ratio is achieved, so that the support frame 14 is tensioned with relatively little effort.

[0047] The two right-hand partial illustrations of the Fig. 5 The figures show the situation shortly before and at the point where the extended end position is reached. In the second-to-last figure (second from the right), the long lever arm 74 and the short lever arm 72 form a straight line. In this configuration, the joint 73 is at its lowest point, meaning the support frame 14 is maximally extended.

[0048] As the long lever arm 74 pivots upwards further until it reaches its end position parallel to the upright 12, the short lever arm 72 bends away from the long lever arm 74 again, so that the joint 73 assumes a slightly higher position than at its lowest point. This means that the support frame 14 is minimally relaxed, and in this position, the tension on the support frame 14 is the one intended for its operation in the open position. This tension is slightly less than the tension at the lowest point of the joint 73. Therefore, to relax the support frame 14 and pivot the long lever arm 74 downwards from its upward end position, a force greater than the force acting on the long lever arm 74, or on the support frame 14, in its end position must be applied.In other words, the force ratios are such that the long lever arm 74 is pulled towards the upright tube 12 between the position shown second to last and the end position shown on the right. Force must therefore be applied until the short lever arm 72 and the long lever arm 74 are aligned. Only after the joint 73 has passed its lowest point during the tensioning process do the force ratios support the further relaxation of the support frame 14. This can also be assisted by manually actuating the long lever arm 74 downwards, since the rigid push-pull rod 54 transmits the upward movement of the joint 73 to the second pulley holder 36 of the block and tackle 32.

[0049] The stop body 78 can also have a clamping recess for the long lever arm 74 of the hand lever 70, which further assists in locking the long lever arm 74.

[0050] The in the Figuren 4 und 5 The actuating mechanisms 50 shown are partially arranged close to the ground, which means that a person operating the actuating mechanism 50 does not obstruct the opening support frame 14.

[0051] All features mentioned, including those discernible from the drawings alone as well as individual features disclosed in combination with other features, are considered essential to the invention, both individually and in combination. Inventive embodiments may be fulfilled by individual features or a combination of several features, provided they fall within the scope of protection of the appended claims. Bezugszeichenliste

[0052] 10 Clamping device 12 Standpipe 14 Support frame 16 Support arm 17 Canopy support 18 Support strut 20 First center bracket 22 Second center bracket 30 Spreading mechanism 32 Pulley block 33 Upper suspension 34 First pulley holder 35 Upper anchor point 36 Second pulley holder 37 Lower anchor point 38 Pulleys 39 Deflection pulley 40 Pulley block rope 42 Quick end of pulley block rope 50 Actuating mechanism 52 Pull rope 54 Rigid push / pull rod 60 Lever 62 Hand pull rope 63 Deflection pulley 64 Hand crank 65 Hook 66 Foot pedal 67 Pivot point 68 Hand lever 70 Hand lever 72 Short lever arm 73 Joint 74 Long lever arm 75 Handle 76 Horizontal pivot axis 78 Stop body 80 Locking device 90 Power assist device 92 Coil spring 93 Coil spring stop 94 Weight

Claims

1. A spreading mechanism (30) for an expandable apparatus (10) including a stanchion (12) and an expandable supporting structure (14) having several pairs of support arms (16) extending apart in a star-shaped manner and support struts (18) hinged to the support arms (16), wherein the support arms (16) are hinged to a first central fixture (20) and the support struts (18) are hinged to a second central fixture (22), and the spreading mechanism (30) is designed to expand or close the supporting structure (14) by reducing or increasing the distance between the first central fixture (20) and the second central fixture (22), characterized in that the spreading mechanism (30) includes an actuating mechanism (50) and a pulley block (32) with a pulley block rope (40), a fixedly affixed first pulley block roll holder (34) and a movable second pulley block roll holder (36) each with one or more pulley block rolls (38), through which the pulley block rope (40) is guided, characterized in that the actuating mechanism (50) is connected to the movable second pulley block roll holder (36) of the pulley block (32) in such a way that an actuation of the actuating mechanism (50) causes a deflection of the movable second roll holder (36), and a fast end (42) of the pulley block rope (40) is connected to the first central fixture (20) or to the second central fixture (22) in such a way that, when the actuating mechanism (50) is actuated, it acts in a shifting manner on the central fixture (20, 22) to which it is connected, in order to change the distance of the central fixtures (20, 22) to each other, wherein the pulley block (32) is disposed in the interior of the stanchion (12).

2. The spreading mechanism (30) according to claim 1, wherein the pulley block (32) has a transmission ratio being between 2:1 and 10:1, in particular between 4:1 and 8:1.

3. The spreading mechanism (30) according to any one of claims 1 to 2, including a force assistance device (90), which is designed to permanently exert a force on the movable second pulley block roll holder (36) of the pulley block (32), which force is directed in the direction of expanding the supporting structure (14).

4. The spreading mechanism (30) according to claim 3, wherein the force assistance device (90) is designed as a spring device with a spring or a combination of springs, in particular spiral spring (92), gas spring and / or gas tension spring, and / or as a weight (94).

5. The spreader mechanism (30) according to claim 4, wherein the spring device has a linear or degressive or progressive spring characteristic.

6. The spreading mechanism (30) according to any one of claims 1 to 5, wherein the actuating mechanism (50) is connected tightly to the movable second pulley block roll holder (36) of the pulley block (32).

7. The spreading mechanism (30) according to claim 6, wherein the actuating mechanism (50) is connected to the movable second pulley block roll holder (36) of the pulley block (32) via a pull rope (52), a pull chain or via a rigid pull push rod (54).

8. The spreading mechanism (30) according to any one of claims 1 to 7, wherein the actuating mechanism (50) is designed as a lever (60), electric winch, as a hand pull rope (62), as a hand crank (64), foot pedal (66) or hand lever (68) for a pull rope (52), or as a hand lever (70) for a rigid pull push rod (54).

9. The spreading mechanism (30) according to any one of claims 1 to 8, wherein a locking apparatus (80) for the actuating mechanism (50) is included, or the actuating mechanism (50) is self-locking.

10. The spreading mechanism (30) according to claim 8 or 9, wherein the hand lever (68, 70) comprises a short lever arm (72) and a long lever arm (74), wherein the short lever arm (72) is connected at one end to the movable second pulley block roll holder (36) of the pulley block (32) and is articulated jointed at its other end with the long lever arm (74), wherein the long lever arm (74) is pivotally affixed to the stanchion (12) at a first distance from the connection to the short lever arm (72) about a horizontal axis of rotation (76), wherein the first distance and a second distance of the horizontal axis of rotation (76) from the stanchion (12) are chosen such that in the case of opening of the expandable supporting structure (14) by pivoting the long lever arm (74) from a downward-pointing end position to an upward-pointing end position, the end of the short lever arm (72) connected to the movable second pulley block roll holder (36) of the pulley block (32) passes through a low point and upon reaching the upward-pointing end position of the long lever arm (74) assumes an end position above the low point.

11. An expandable apparatus (10) having a stanchion (12) and an expandable supporting structure (12) with a plurality of pairs of support arms (16) extending apart in a star-shaped manner and support struts (18) hinged to the support arms (16), wherein the support arms (16) are hinged to a first central fixture (20) and the support struts (18) are hinged to a second central fixture (22), as well as a spreading mechanism (30), which is designed to expand or close the supporting structure (14) by reducing or increasing the distance between the first central fixture (20) and the second central fixture (22), characterized in that the spreading mechanism (30) is designed according to any one of claims 1 to 10.

12. The expandable apparatus (10) according to claim 11, characterized in that it is designed as a standing umbrella, in particular a center-mast umbrella or side-arm umbrella, as a rotary clothes dryer or as a combination of rotary clothes dryer and center-mast umbrella.

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