Patent Publication Number: US-7717383-B2

Title: Adjustable support mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of International Patent Application No. PCT/US2004/039148, filed Nov. 22, 2004, which claims the benefit of Australian Patent Application No. AU2003906642, filed Nov. 24, 2003, both of which are incorporated by reference herein in their entirety. 
     1. Field of the Invention 
     The present invention relates to Supports that facilitate adjustment of one bracket relative to another 
     2. Background to the Invention 
     The need for a mechanism that enables the adjustment of the height of a keyboard support surface relative to a fixture is well recognized. My Australian Patent No. 65578/90 and my U.S. Pat. No. 5,292,097, disclose improved four-bar or four element parallelogram mechanisms that allow a support surface height to be adjusted relative to a fixed surface. These mechanisms were of a type which enabled a working platform to be attached to a moveable element or bracket, which in turn was pivotally connected to one end of a pair of substantially parallel link elements, which in turn were pivotally connected at their other end to a fixed element or bracket, which was capable of being affixed or otherwise mounted to the underside of a desk-top. A feature of these mechanisms was their ability to maintain a substantially parallel relationship between the moveable element or bracket and the fixed element or bracket throughout the height adjustment range. 
     In many four-bar linkage mechanisms, the amount of rotation of the moveable bracket relevant to the fixed bracket is limited by the overlapping and interference of the link arms. Also in many four-bar linkage mechanisms, the rotational movement of the moveable bracket relative to the fixed bracket may require protection guards to be positioned to avoid the creation of pinch points. Also in many adjustable support mechanisms, the linkage arms and brackets may intrude significantly into knee-hole space and otherwise interfere with the operator using the attached support platform. 
     It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art in Australia or any other country. 
     The present invention attempts to overcome limitations of other platform support mechanisms. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention there is provided an adjustable support mechanism comprising:
         a first bracket;   a second bracket;   a connecting member pivotally coupled to the first bracket at a first position and pivotally coupled to the second bracket at a second position spaced from the first position; and   a linking member coupled to the connecting member so as to be movable in relation to the connecting member, wherein the linking member is arranged to engage the bracket: and the second bracket such that pivotal movement of the first bracket in a first rotational direction is related to movement of the linking member, which is in turn related to pivotal movement of the second bracket also in the first rotational direction.       

     According to a second aspect of the present invention there is provided an adjustable support mechanism comprising:
         a. first bracket;   a second bracket;   a connecting member pivotally coupled to the first bracket at a. first position and pivotally coupled to the second bracket at a second position spaced from the first position; and   a linking member coupled to the connecting member so as to be movable transversely in relation to a line between the first position and the second position,   wherein the linking member is arranged to engage the first bracket such that pivotal movement of the first bracket in a first rotational direction is related to transverse movement of the linking member in a first transverse direction:   wherein the linking member is also arranged to engage the second bracket such that pivotal movement of the second bracket in the first rotational direction is also related to the transverse movement of the linking member in the first transverse direction. Preferably the first bracket comprises a planar member. Preferably the second bracket comprises a planar member. Preferably the first bracket is coupled to a first end of connecting member. Preferably the second bracket is coupled to a second end of connecting member. Preferably the linking member is coupled to the connecting member so as to be slidable in a direction perpendicular to the length of the connecting member, the length being parallel to the line between the first position and the second position.       

     Preferably the coupling arrangement between the connecting member and the linking member includes a transverse bar extending across the connecting member and a sleeve or spaced apart collars through which the transverse bar passes so as to guide the movement of the linking member relative to the connecting member. 
     Alternatively the coupling arrangement is in form of a sleeve at each end of the linking member through which an axle of each respective bracket passes, each sleeve being slidable along at least part of the length of each respective axle. 
     Preferably each bracket comprises a screw drive having an axis of rotation coinciding with axis of pivotal rotation of the bracket. Preferably the linking member comprises a follower for engaging the thread of each screw drive. Preferably the linking member and each bracket are each in a screwjack arrangement such that pivoting of each bracket with respect to connecting member causes rotation of the respective screw with respect to connecting member and linking member, which in turn causes transverse movement of the respective followers and thus in turn transverse movement of the linking member with respect to the connecting member. Preferably each follower is one of a pin, a rack a nut or a nut portion. 
     Typically the pitch of the screw of the first bracket is the same as the pitch of the screw of the second bracket, so that a change in angle between first bracket and connecting member is the same as the change in angle between second bracket and the connecting member. 
     Preferably the planar member of first bracket is parallel to the planar member of second bracket. Preferably the planar member of second bracket is parallel to planar member of first bracket through a range of movement of second bracket with respect to the first bracket. 
     In one embodiment the second bracket comprises an angle adjustment means so that the angle of the second bracket may be adjusted so that a support surface thereof is not parallel with the planar member of the first bracket. 
     Preferably the angle adjustment means comprises the follower being transversely movable and further comprises a shifter arranged to control the transverse position of the follower relative to the linking member. 
     Alternatively the angle adjustment means comprises the drive being transversely movable with respect to the connecting member; and further comprises a shifter arranged to control the transverse Position of the screw drive. Preferably the screw drive is also transversely slidable with respect to the planar member. Preferably the planar member is orbitally coupled to the screw drive. 
     Preferably the first bracket is arranged to be connectable to a stationery object, such as a bench or desk. 
     Preferably the supporting mechanism comprises a locking mechanism arranged to prevent transverse movement of the linking member with respect to connecting member when the locking mechanism activated, thereby locking the brackets in position relative to each other. Preferably the locking mechanism is in the form of an interference engaging region of the linking member being movable so as to engage an interference engaging region of the connecting member. 
     Alternatively the support mechanism comprises a locking mechanism arranged to prevent pivoting of one of brackets with respect to connecting member thereby locking the position of first bracket with respect to the second bracket when the locking mechanism is activated. 
     In a further alternative, the support mechanism comprises a locking mechanism arranged to bias the second bracket to attempt to orbitally rotate about the first bracket. or rotate the planar member of the second bracket so as to not be parallel with the planar member of the first bracket thereby locking the position of first bracket with respect to second bracket. Preferably the bias is the weight of the support mechanism under the influence of gravity when the planar member of the first bracket is horizontal. 
     Preferably the second bracket comprises a weight mounted distally from the pivotal coupling to the connecting member such that when the first bracket is substantially horizontal leverage of the weight with respect to connecting member acts as the locking bias. 
     Preferably pivotal movement of either bracket in relation to the connecting member in a second rotational direction, opposite to the first rotational direction, is related to transverse movement of the linking member is a second transverse direction, opposite the first traverse direction. 
     According to a third aspect of the present invention there is provided an adjustable support mechanism comprising:
         a first bracket;   a second bracket;   a connecting member pivotally coupled to the first bracket at a first position and pivotally coupled to the second bracket at a second position spaced from the first position; and   a linking member pivotally coupled to the connecting member so as to be pivotally about a point midway along a line between the first position and the second position,   wherein the linking member is arranged to engage the first bracket such that pivotal movement of the first bracket in a first rotational direction is related to pivotal movement of the linking member in a first pivotal direction,   wherein the linking member is also arranged to engage the second bracket such that pivotal movement of the second bracket in the first rotational direction is also related to the pivotal movement of the linking member in the first pivotal direction.       

     In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 
    
    
     
       DESCRIPTION OF DRAWING 
       In order to provide a better understanding, preferred embodiments of the present invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a side elevation of a preferring embodiment of an adjustable support mechanism according to the present invention; 
         FIG. 2  is a lower perspective view of a first alternative embodiment of an adjustment support mechanism according to the present invention; 
         FIG. 3  is a lower perspective view of the adjust support mechanism of  FIG. 2  with a linking member removed; 
         FIG. 4  is a lower perspective view of the adjustable support mechanism of  FIG. 2  with a connecting member removed; 
         FIG. 5  is an upper perspective view with a partial cut away of the adjustable support mechanism of  FIG. 2 ; 
         FIG. 6  is an upper perspective view of a second preferred embodiment of an adjustable support mechanism according to the present invention; 
         FIG. 7  is a lower perspective view of the adjustable support mechanism of  FIG. 6 ; 
         FIG. 7A  is a bottom view of an alternative arrangement of coupling the linking member  18  to the screw drive  34 ; 
         FIG. 8  is a lower perspective view of a third alternative embodiment of an adjustable support mechanism according to the present invention; 
         FIG. 9  is a lower perspective view of the adjustable support mechanism of  FIG. 8  with brackets of the support mechanism in different positions relative to one another compared to the positions of the brackets in  FIG. 8 ; 
         FIG. 10  is a fourth alternative embodiment of an adjustable support mechanism according to the present invention; 
         FIG. 11  is a perspective view of a half nut used in a further alternative embodiment of an adjustable support mechanism according to the present invention; 
         FIG. 11A  is a bottom view of an alternative embodiment of a linking member and screw drive of an adjustable support mechanism according to the present invention; 
         FIG. 11B  is an example of a helical crossed gear; 
         FIG. 11C  is a perspective view of an embodiment of an adjustable support mechanism according to the present invention utilizing a half nut. 
         FIG. 11D  is a perspective view of an embodiment of an adjustable support mechanism according to the present invention utilizing a full nut. 
         FIG. 11E  is a perspective view of an embodiment of an adjustable support mechanism according to the present invention utilizing a helical mesh teeth arrangement 
         FIG. 12  is a bottom view of a variation of the preferred embodiment shown in  FIGS. 6 and 7 ; 
         FIG. 13  is an upper perspective view of an adjustable support mechanism with a locking means; 
         FIG. 13A  is an enlarged upper perspective view the locking means of  FIG. 13  shown including a cut away portion of the side wall of the connecting member; 
         FIG. 14  is a partial lower perspective view of a part the preferred embodiment shown in  FIG. 6  with an angle adjustment means and with a bracket shown parallel with a connecting member of the adjustable support mechanism; 
         FIG. 15  is a partial lower perspective view showing the same portion of the adjustable support mechanism shown in  FIG. 14  with the angle adjustment means having changed the angle of the bracket relative to the connecting member; 
         FIG. 16  is an enlarged partial lower perspective view  5  with a cutaway portion with the adjustable support mechanism of  FIG. 14 ; 
         FIG. 17  is a lower perspective view of a further alternative embodiment of the adjustable support mechanism in accordance with the present invention including a locking means; 
         FIG. 18  is a partial cutaway side elevation of the embodiment shown in  FIG. 17  with the locking means engaged; 
         FIG. 19  is a partial cutaway side elevation of the embodiment shown in  FIG. 17  with the locking means disengaged; 
         FIG. 20  is a partial cutaway side elevation of a further embodiment of the adjustable support mechanism with an alternative angle adjustment means to that shown in  FIG. 14  with the bracket in the first position; and  FIG. 21  is a partial cutaway side elevation of the embodiment shown in  FIG. 20  with the adjustment means adjusting the angle of the bracket to the second position. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 1  there was shown an adjustable support mechanism  10  which includes a first bracket  12  pivotally connected to a connecting member  16  which is in turn pivotally connected to a second bracket  14 . A linking member  18  extends between axles of the brackets and is coupled to the connecting member so as to be transversely slidable with respect to the connecting member  16 . The linking member  18  is coupled to each of the axles of the brackets  12  and  14  so that pivoting of the brackets  12  and  14  with respect to the connecting member causes transverse movement of the linking member  18 . 
     Referring to  FIGS. 2 to 5 , in this embodiment the pivotal connections between the brackets  12  and  14  and the connecting member  16  are shown in more detail, as is the coupling between the brackets  12  and  14  and the linking member  18 , as well as the coupling between the linking member  18  and the connecting member  16 . 
     The bracket  12  includes a planar member  32  for fixing to a stationary object, such as a bench or desk, and a screw drive  34 . The bracket  14  includes a planar member  32  for fixing to a movable object, such as a keyboard support platform, and a screw drive  34 . The pivotal coupling of the bracket  12  to the connecting member  16  and the drive arrangement between the linking member  18  is the same as is the case for bracket  14 . For convenience only one will be described. 
     The screw drive  34  is formed of a cylinder  20  having a helical groove  26  extending around its periphery. A hole  36  extends through the cylinder  20 . The bracket  12  is pivotally coupled to the connecting member  16  via an axle in the form of a shaft  30  which extends through the hole  36  and holes in side walls  28  of the connecting member  16 . The axle shaft  30  is connected to the side walls  28 , but cylinder  20  can rotate about axle shaft  30 . In other embodiments the axle shaft  30  rotates in relation to the side walls  28  and is fixed in relation to the cylinder  20 . 
     The linking member  18  includes collars  22  at either end. The collars  22  receive and circumferentially surround the cylinders  20 . The collars  22  are shorter than the length of the cylinder  20 . Inside each collar  22  is a inwardly projecting follower pin  26  that is received by the groove  24  of the screw drive  34 . But for the follower pin  26  engaging with the groove  24  the linking member  18  would be free to slide from side to side of the connecting member  16  along the length of the cylinder  20 . The follower pin  26  and helical groove  24  form a screw jack arrangement so that pivoting of the bracket  12  causes rotation of the screw drive  34 , which in turn transversely drives the follower pin  26  and thus the linking member  18  in relation to the connecting member  16 . 
     The direction of rotation or pitch of the groove  24  in the screw drive  34  is the same for each bracket  12  and  14  so that pivotal rotation of the bracket  12  causes corresponding pivotal rotation in the bracket  14  in the same pivotal direction and vice versa. 
     In  FIG. 4 , holes  38  are shown for securing the cylinders  20  to the planar members  32  of the brackets by the use of screws/bolts. 
     In  FIG. 5  a gap  40  is shown between pins  26 . A spring (not shown) may be positioned in the gap to urge the pins  26  apart and to ensure they engage their respective grooves  26 . 
     Referring to  FIGS. 6 and 7 , this embodiment of the adjustable support mechanism  10  is similar to the previous embodiment although in this case there are some differences to the screw drive  34  and the linking  18 , In this embodiment the screw drive  34  has a series of parallel, grooves  24  in the cylinder  20  that do not make a complete rotation of the screw drive  34 . The linking member  18  has three follower pins  26  each of which project into a corresponding one of the three grooves  24  of the screw drive  34 . 
     The linking member  18  has a hole  46  there through near each of the ends. A securing pin  42  passes through each hole  46  to couple the linking member  18  to the connecting member  16  in a manner which allows the linking member  18  to transversely slide along the securing pins  42  in relation to the connecting member  16 . But for the follower pins  26  the linking member  18  would be free to slide along the length of the securing pins  42 . The securing pins  42  pass though a corresponding hole  44  in the side walls of the connecting member  1 . 6  and are fixed to the connecting member  16 . 
       FIGS. 8 and 9  show a further alternative embodiment with two linking members  18 . Each of the linking members  18  has a collar  22  at either end. A follower pin (not shown) projects inwardly from the collars  22  to engages with a corresponding helical groove  24  on the screw drive  20 . It can be seen that the direction of rotation of the grooves  24  towards either end of the screw drive  34  are in opposite directions so that with rotation of the screw drive  34  the pair of linking members  18  either move towards one another or move apart from one another. 
     In  FIG. 9  essentially the same adjustable support mechanism is shown with the relative position of the brackets  12  and  14  being different when compared to  FIG. 8 . The linking members  18  are their maximum distance apart. Providing two linking members  18  moving in opposite directions, neutralizes thrust created as the linking members  18  move. 
     Referring to  FIG. 10  a similar concept to that shown in  FIGS. 8 and 9  is employed in this adjustable support mechanism. There are two linking members  18 , but the linking members  18  are not coupled with collars  22 , instead there are securing pins (not shown) similar to those used in the embodiment shown in  FIG. 7 . In case each linking member  18  has a hole (not shown) there through near either end through which the securing pins are positioned. Each linking member  18  has a follower pin at either end that engages with the corresponding groove  24  in the screw drives  34 . 
     The collar and follower pin arrangement may be replaced with a half nut  50  as shown in  FIG. 11  and  FIG. 11C  or a full nut  51  as shown in  FIG. 11D . An inwardly projecting thread  52  on the inside of the half nut  50  or full nut  51  replaces the follower pin. The half nut or full nut arrangement is believed to be advantageous as loading is distributed along the inwardly projecting thread  52  rather than on a relatively small pin. It will also be appreciated that the screw drive may instead of having grooves have one or more threaded projections with the half nut having inner grooves rather than an inwardly projecting thread. 
     In  FIG. 11A  an alternative coupling arrangement between the screw drive  34  and linking member  18  is shown. In this embodiment linking member  18  pivots about axle  19  which extends from the back plate  68  of the connecting member  16 . In this embodiment the screw drive  34  includes helical mesh teeth  27  and the follower is in the form of helical mesh teeth  25 . The teeth  27  and  25  form a helical crossed gear. An example of a helical crossed gear is shown in  FIGS. 11B &amp; 11D . The linking member  18  may in effect be formed by removing the superfluous side portions above and below the lines indicated as X-X in  FIG. 11B . 
     Referring to  FIG. 12 , a biasing means  54  in the form of a spring is shown. The spring  54  urges the linking member  18  to return to a rest position. This encourages the planar members  32  to remain in the same plane if the return position of the linking member  18  is in the centre of the connecting member  16 , as shown. Movement of the linking member  18  in either direction due to pivotal movement of the brackets  12  and  14  with respect to the connecting member  16  will cause translation of the brackets  12  and  14  with respect to one another. Such movement must overcome the bias of the spring  54 . when the moving force ends and subject to the adjustable support member not being locked in position, the biasing force will urge the linking member  18  to return to the rest position. The brackets  12  and  14 . will also translate back to their rest positions relative to one another. 
     In  FIGS. 13 and 13A  the adjustable support mechanism  10  includes a locking mechanism. In this embodiment axle shaft  30  is fixed to the cylinder  20  and able to rotate within the hole  36 . The locking mechanism includes a threaded end  60  of shaft  30  and a knob  56  on the outside of the connecting member  16 . The knob  56  includes a jam  58  on an inner face adjacent to the side wall  28  of the connecting member  16 . The shaft  60  in threadingly connected to the knob  56  so that when the knob  56  is rotated the jam  58  moves towards or away from the sidewall  28 . When the jam  58  moves far enough towards the side wall  28  it will contact the side wall  28  and prevent the shaft  30  from rotating with respect to the connecting member  16  thus locking the adjustable support mechanism in position. Alternatively the knob  56  may be fixed to the cylinder  20  via the shaft  30  (without the thread) and may be rotatable about its length with respect to the connecting member  16 , so that it can be use to assist in pivoting the cylinder  20  in relation to the connecting member  16 , thereby making adjustment of the support easier. 
       FIGS. 14 ,  14 A and  15  show an angle adjustment mechanism comprising a shaft  30  fixed to a knob  62  on the outside of the connecting member  16 . The shaft  30  is threadingly coupled to the side wall  28  of connecting member  16 . The shaft  30  is also engaged with the cylinder  20  so that transverse movement of the shaft  30  causes transverse movement of the cylinder  20 , but rotation of the cylinder  20  does not cause rotation of the shaft  30  and vice versa. When the knob  62  is rotated it moves through the thread in the side wall  28  which causes the shaft  30  and therefore the cylinder  20  to move transversely relative to the connecting member  16 . The cylinder  20  may be transversely movable in relation to the connecting member  16  and planar member  32  of the bracket  14 . The cylinder  20  must be shorter than the width of the connecting member  16 , The cylinder  20  may be orbitally coupled to the planar member  32  of the bracket  14  so that the planar member  32  moves in an orbiting manner about the centre of rotation of the cylinder  20  with rotation of the cylinder  20 . Due to the screw jack arrangement with the linking member  18  transverse movement of the cylinder causes the screw drive  34  to rotate with respect to the connecting member  16  thereby adjusting the angle of the planar member  32  of the bracket relative to the connecting member  16 . An alternative locking means is shown in  FIGS. 17 to 19 . One hole  66  of the holes  46  in the linking member  18  (through which one of the securing pins  42  passes) is slotted to allow the linking member  18  to move slightly towards or away from a backing plate  68  of the connecting member  16 . The linking member  18  includes a corrugated region  70  adjacent a corresponding corrugated region  72  of the backing plate  68 . 
     By allowing the linking member  18  to move slightly away from the connecting member  16  the corrugated regions do not engage. However, when the linking member  18  moves towards the connecting member  16  the corrugated regions engage thus causing interference there between which prevents transverse movement of the linking member  18  with respect to the connecting member  16 . This is turn acts as a lock to the adjustable member  16 . This in turn acts as a lock to the adjustable support mechanism. It can be seen in  FIG. 19  that by slightly tilting the bracket  14  in relating the connecting member  16  the linking member  18  drops slightly and moves away from the connecting member  16 . 
     It is preferred that the manner of moving the linking member  18  towards the connecting member  16  is by pivoting the bracket  14  in a direction naturally inclined to be taken under the influence of gravity. Thus the weight of the bracket  14 , by leverage under gravity, locks the adjustable support mechanism. If the weight of the bracket is insufficient it may include a weight on the underside away from the connecting member  16  so that the sufficient force is applied to lock the support mechanism. 
     A further locking mechanism can be achieved by use of friction between the follower and the screw drive. Yet a further locking mechanism may be as follows. Under the weight of the support mechanism and its load, gravity will act as a bias which would tend to rotate the second bracket  14  orbitally in relation to the first bracket when the first bracket is positioned horizontally and fixed to a stationary object. This will tend to cause the second bracket  14  to pivot in the opposite direction that the first bracket  12  is inclined to pivot under drive via the linking member  18 . Thus the adjustable support mechanism may be locked under its own, weight. 
     A further angle adjustment means is shown in  FIGS. 20 and 21  where the bracket includes a second pivotal connection  74  between the cylinder  20  and the planar member  76 . The second pivotal connection  74  is formed on a relatively short spacing member  78  which spaces the second pivotal connection  74  from the pivotal connection formed between the cylinder  20  and the connecting member  16 . 
     The method of use and operation of the present invention will now be described with reference to the accompanying drawings. 
     The support bracket of the present invention has Particular application supporting a computer keyboard support platform relative to a bench or desk. It will be appreciated that numerous other applications can be found for the support mechanism but the computer desk support will be described for convenience. The first bracket is coupled to the desk generally by screwing it in the underside of the desk so that the planar member is horizontal. The keyboard support platform is coupled to the planar member of the second bracket. By raising and lowering the keyboard support platform relative to the desk in a parallel manner the height of the keyboard support platform may be adjusted. A considerable range of up and down movement can be provided by the support mechanism. It also provides advantage over the prior art that there are not parallelogram links and the present invention is relatively slim line. In addition there are no pinch points that are often involved in link arm and in particular parallelogram link arm arrangements. 
     The position of the keyboard support platform may be maintained by locking the adjustable support mechanism as described above. Furthermore the angle of the keyboard support platform relative to the desk may be adjusted by using the angle adjustment mechanism as described above. 
     A skilled addressee will realize that the present invention has advantages over the prior art. In addition to the advantages mentioned above, in comparison to the some prior art support mechanisms, a support mechanism according to the present invention allows a greater range of movement of the second bracket relative to the first bracket. 
     A person skilled in the art will realize that modifications and variations may be made to the present invention without departing from the basic inventive concept. Some of the modifications and variations have been described herein, although it will be appreciated that other variations may be made which include further alternatives to the locking mechanism, the arrangement of the linking member in relation to the connecting member as well as variations to the angle adjustment means. 
     Such modifications and variations are intended to all within the scope of the present invention, the nature of which is to be determined from the foregoing description and appended claims.