Patent Publication Number: US-2004055976-A1

Title: Display stands

Description:
[0001] This invention relates to a display stand for a flexible laminar member, of the kind in which the laminar member is movable between a display position and a storage position in which it is retracted round a spring-loaded rotatable member. The laminar member may for example be a poster.  
       [0002] In such display stands which are presently on sale, the spring which acts on the rotatable member normally acts in torsion. The spring is attached at one end to the rotatable member and at the other is held in a housing in which the rotatable member is inserted. The laminar member is pulled manually from the storage position, which rotates the rotatable member against the force in the spring. The spring also acts to retract the laminar member again by rotating the rotatable member in the opposite direction. The spring is pre-tensioned and is not adjustable. A disadvantage of this construction is that it can be unsafe. The spring is pre-loaded with a high degree of torsional force so that the display stand can cope with relatively stiff or heavy laminar members. When such a display stand is used with a flexible or light laminar member, it will be appreciated that when the spring is released to retract the laminar member, there is a danger that misplaced fingers could be painfully trapped.  
       [0003] According to the present invention, a display stand for a flexible laminar member of the kind set forth has a housing in which the rotatable member is mounted, the rotatable member being acted on by a torsion spring, and an adjusting means is provided for adjusting the torsional force of the torsion spring.  
       [0004] With the display stand according to the invention the spring can be adjusted to provide a suitable tension to enable safe retraction of the laminar member, depending on its stiffness or weight. The display stand is therefore safer to use.  
       [0005] A further advantage of the invention is that the laminar member is replaceable. This is because it is possible to release the tension in the spring completely in the display stand according to the invention, allowing manipulation of the laminar member when it is fully extended.  
       [0006] Preferably the torsion spring has one end secured to the rotatable member and the other end secured to the adjusting means comprising a ratchet member, the ratchet member being movable between a first position in which it is fixed relative to the housing, and a second position in which it is rotatable relative to the housing by means of a tool introduced through an aperture in the housing.  
       [0007] Thus, the torsional force of the spring can readily be adjusted when the rotatable member is in position in the housing by inserting the tool through the aperture to move the ratchet member into the second position and rotating the ratchet member to adjust the spring. The torsional force in the spring may be increased in steps by rotating the ratchet member in one direction, or released by rotating the ratchet member in the other direction.  
       [0008] The ratchet member includes teeth co-operating with a stop on the housing to allow the ratchet member to rotate in only one direction in the first position. The ratchet member is moved axially relative to the rotatable member between its first and second positions. It is preferably biassed into its first position by a second spring acting between the ratchet member and the housing. The ratchet member has an appropriate formation to enable it to be operated by the tool, which may be a screwdriver or an Allen key.  
       [0009] The housing of the display stand preferably forms a base for the display stand. The display stand may also include a support member for supporting the laminar member in the display position. The support member preferably comprises an upright member and a cross-member.  
       [0010] Preferably the housing contains two spring-loaded rotatable members so that, in use, the display stand displays two laminar members and is a twin-sided display stand.  
       [0011] The invention also relates to the combination of the display stand with one or two laminar members. 
     
    
    
     [0012] An embodiment of the invention is illustrated, by way of example only, in the accompanying drawings, in which:  
     [0013]FIG. 1 shows a display stand for a flexible laminar member; and  
     [0014]FIG. 2 is a longitudinal section through a base of the stand showing a rotatable member inserted in a housing. 
    
    
     [0015] The display stand  1  of FIG. 1 is for a flexible laminar member  2  such as a poster. The display stand  1  has a base  3 , an upright  4  and a top cross-member  5 . The laminar member  2  is movable between a storage position, in which it is retracted round a spring-loaded rotatable member  6  in the base  3 , and a display position as shown, in which it is attached to the top cross-member  5 .  
     [0016] The rotatable member  6  and its associated mechanism are shown in more detail in FIG. 2. In FIG. 2, the base  3  has a pair of housing end caps  7  on which the rotatable member  6  is mounted. The member  6  comprises a hollow cylindrical roller  8  to which the laminar member  2  (not shown in FIG. 2) is attached. A bush  9  fits tightly into each end of the roller  8  and forms a cylindrical bearing surface  10  for rotation of the roller  8  on an outer surface of a hollow cylindrical axial extension  11  on a respective housing end cap  7 . A slider  12  is also accommodated in the roller  8 , and can slide axially in the roller  8 , but is constrained to rotate with it. The slider  12  is of stepped outline, with a cylindrical portion  13  fitting the inside of the roller  8 , and a portion  14  of smaller diameter and with an end taper  15 . One end of a torsion spring  16  fits over the portion  14 . The other end of the spring  16  fits over a similar part of a ratchet member  17 , and a tube  16 ′ encircles the central part of the spring  16  to keep it in place.  
     [0017] The ratchet member  17  is of stepped cylindrical outline with a blind bore  18  opening towards the slider  12 , and a taper  19  at the end adjacent the slider  12 , over which the spring  16  fits. The other end of the ratchet member  17  is received within an axial extension  11  of the adjacent end cap  7 , for axial and rotational movement. The closed end  20  of the ratchet member  17  has a slot  21  for a screwdriver (not shown) which can be inserted through a central aperture  22  in the end cap  7 , and used to rotate the ratchet member  17 .  
     [0018] At its closed end  20  the ratchet  17  also has dog teeth  23  formed round its periphery, and co-operating with the end cap  7  to form a ratchet mechanism allowing rotational movement of the member  17  in one direction, but preventing such movement in the other direction. The ratchet member  17  is biassed into engagement with the end cap  7  by a compression spring  24  acting between a shoulder  25  at a step in diameter of the ratchet member  17  and a locking ring  26  attached to the axially inner end  27  of the end cap extension  11  by a snap fitting. The spring  24  urges the ratchet member into engagement with the end cap  7  so that it is in a first position (as shown) in which it is fixed relative to the housing end cap  7 . However, the ratchet member  17  is movable axially against the force in the spring  24  into a second position in which it is rotatable relative to the housing end cap  7 , and so can alter the torsional force in the spring  16 .  
     [0019] In use, the mechanism is assembled as shown, and the laminar member  2  is attached to and rolled up round the roller  8 . The assembly shown in FIG. 2 is inserted in the base of the display stand, with the free end of the laminar member  2  projecting from the housing. If, on pulling the laminar member  2  out, the torsional force of the spring  16  is found to be incorrect, it can be adjusted by inserting a screwdriver through the aperture  22  and using the screwdriver to move the ratchet member  17  against the force in the spring  24 , and to rotate the ratchet member  17 . If the spring force is to be increased, the ratchet member  17  is rotated in one direction, to wind up the spring  16  in steps dictated by the ratchet teeth  23 . If the spring force is to be decreased, the ratchet member  17  is allowed to rotate in the other direction, under the influence of the spring  16 . It is therefore simple to obtain the correct force for the spring  16 .  
     [0020] When the laminar member  2  is being moved between the storage and display positions the ratchet member  17  remains fixed relative to the housing end cap  7 , so that the spring  16  then operates as required, on relative rotation of the slider  12  with roller  8  and the ratchet member  17 .