Abstract:
A lifting mechanism is disclosed for a bed deck having a top surface where a user may lie thereon and a bottom surface. The bed deck is rotatably mounted to a bed platform having a recessed storage area. The bed deck can be moved from a horizontal to a non-horizontal position. The lifting mechanism is at least partially disposed in the recessed storage area and includes a torsion bar having a first end and a second end; a cam follower rigidly mounted to the torsion bar proximal to the first end; an anchor arm rigidly mounted to the torsion bar proximal to the second end; a mechanism for mounting the torsion bar with the bed platform; and a cam mounted to the bottom surface of the bed deck.

Description:
RELATED APPLICATIONS 
   This application is a non-provisional patent application of U.S. provisional patent application Ser. No. 60/473,630, Filed May 27, 2003, entitled “Lifting Mechanism For A Bed Deck” and is a continuation-in-part of U.S. patent Ser. No. 10/391,091, now U.S. Pat. No. 6,966,080 filed Mar. 18, 2003, which is a continuation-in part of U.S. patent Ser. No. 10/146,153, now U.S. Pat. No. 6,611,973, filed 15 May 2002, the disclosures of which are incorporated herein by reference. 

   BACKGROUND 
   U.S. Pat. No. 6,611,973 (the &#39;973 patent), filed May 15, 2002, for a “Bed Structure with Storage Area”, and assigned to the same assignee as that of the present invention, is incorporated herein by reference. The &#39;973 patent discloses a bed structure with a platform having a recessed storage area and a deck hingedly mounted to the platform such that the same may serve as a surface upon which a user may lie (e.g., for sleeping), and may be rotated upward for access to the storage area.  FIG. 1  shows one embodiment of a bed structure  10  having one or more platforms  12  disposed in spaced relation to one another by a set of end frames  14 . Each platform  12  has a recessed storage area  16  formed therein by sidewalls  18  of the platform  12 . A deck  20  is rotatably mounted to the platform  12  to alternately cover the recessed storage area  16  and provide access to the storage area  16 . 
   Depending on the construction of the deck  20 , it may have a weight well over 100 pounds, and in one embodiment of the bed structure  10  the deck  20  weighs over 190 pounds. Not only does this make it difficult to manually rotate the deck  20  upward, but also presents a serious danger of the deck  20  accidentally falling downward if the deck  20  is “propped-up” to hold open the access to the recessed storage area  16 . Although lifting mechanisms for such decks  20 , such as gas springs, have been proposed for assisting in deck lifting, the high forces needed for upward rotation of the deck  20  from the most downward position would require a very strong gas spring arrangement. Further, gas springs often require maintenance over time and typically wear out within a certain number of cycles. Additionally, these types of lifting mechanisms often do not support holding up the deck  20  at a selected angle of rotation other than a fully “open” position. 
   SUMMARY 
   The lifting mechanism herein disclosed advances the art and overcomes problems articulated above by providing a lifting mechanism that moves a bed deck from a substantially horizontal position to a non-horizontal position while requiring minimal force to effect the movement. 
   In particular, and by way of example only, according to an embodiment, provided is a lifting mechanism for a bed deck, the bed deck being rotatably mounted to a bed platform for movement of the bed deck from a substantially horizontal to a non-horizontal position, including: a torsion bar having a first end and a second end and defining an axis; a cam follower mounted on the torsion bar proximal to the first end; an anchor arm mounted on the torsion bar proximal to the second end; and a cam mounted to the bed deck, wherein a torsional force applied to the torsion bar by rotation of the cam follower about the axis of the torsion bar, relative to a position of the anchor arm, is transferred by the cam follower to the cam to provide a biasing force to the bed deck in the direction of rotation, to move the bed deck from a substantially horizontal to a non-horizontal position. 
   In another embodiment, provided is lifting mechanism for a bed deck, the bed deck being rotatably mounted to a bed platform for movement of the bed deck from a substantially horizontal to a non-horizontal position, including: a torsion bar defining an axis; a cam follower mounted to the torsion bar; at least one bracket for mounting the lifting mechanism to the bed platform; and a cam mounted to the bed deck wherein a torsional force in the torsion bar generated by a rotation of the cam follower about the axis of the torsion bar is transferred by the cam follower to the cam to provide a biasing force to the bed deck in the direction of rotation thereof from the substantially horizontal to the non-horizontal position. 
   In yet another embodiment, provided is a lifting mechanism for a bed deck rotatably mounted to a bed platform, for movement of the bed deck from a substantially horizontal to a non-horizontal position, including: a rotating means for rotating with a first end of a torsion bar to induce a force into the bed deck; an affixing means for affixing a second end of the torsion bar to the bed platform; a limiting means for limiting the rotation of the rotating means; and an adjusting means for adjusting the force induced into the bed deck, wherein the force induced into the bed deck moves the bed deck from the substantially horizontal position to the non-horizontal position. 
   In still another embodiment, provided is a method for manufacturing a lifting mechanism for a bed deck rotatably mounted to a bed platform, for movement of the bed deck from a substantially horizontal to a non-horizontal position, including: affixing an anchor arm to the bed platform; mating a first end of a torsion bar with a cam follower; integrating a second end of the torsion bar to the anchor arm; interfacing the cam follower with a loading cam mounted to the bed deck to induce a load in the torsion bar and rotate the cam follower; securing the cam follower in a loaded position; replacing the loading cam with a cam; and rotatably attaching the bed deck to the bed platform. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side view of a prior art bedding assembly; 
       FIG. 2  is a perspective view of the lifting mechanism in accordance with an embodiment of the present invention; 
       FIG. 3  is an exploded view of the lifting mechanism in accordance with an embodiment of the present invention; 
       FIG. 4  is a perspective view of the cam in accordance with an embodiment of the present invention; 
       FIG. 5  is a partial cross-sectional view of the platform and deck of the present invention showing the deck in horizontal position in accordance with an embodiment of the present invention; 
       FIG. 6  is a cross-sectional view of the platform and deck of the present invention showing the deck in a non-horizontal position in accordance with an embodiment of the present invention; 
       FIG. 7  is a cross-sectional view of the platform and deck of the present invention showing the deck in a non-horizontal position in accordance with an embodiment of the present invention; 
       FIG. 8  is a perspective view of the platform with the lifting mechanism of the present invention, and the deck removed; 
       FIG. 9  is a perspective view of the platform with the lifting mechanism of the present invention, and the deck removed; 
       FIG. 10  is a partial perspective view of one side of the lifting mechanism as mounted to the bed platform within the recessed storage area, in accordance with an embodiment of the present invention; 
       FIG. 11  is a partial perspective view of a second side of the lifting mechanism as mounted to the bed platform within the recessed storage area in accordance with an embodiment of the present invention; and 
       FIG. 12  is a perspective view of the bed platform with the lifting mechanism removed. 
   

   DETAILED DESCRIPTION 
     FIG. 2  shows the lifting mechanism  100  of the present embodiment removed from mounting within the recessed storage area  204  ( FIG. 5 ) of the bed platform  202  ( FIG. 5 ). Cam  102  is shown as well for reference. The lifting mechanism  100  comprises generally the torsion bar or rod  106  with the cam follower  104  rigidly mounted to a first end  108  of the torsion bar  106  and an anchor arm  110  rigidly mounted to a second end  112  thereof. When mounted with the bed platform  202 , the torsion bar  106  axis  105  extends generally in the horizontal plane and defines a lateral direction. 
   Despite the fact that the mounting of the cam follower  104  with the torsion bar  106  is typically rigid, the cam follower  104  is able to rotate about the axis  105  of the torsion bar  106  due to the twisting of the bar  106  in torsion; the twisting of the torsion bar  106  is at a maximum at the first end  108  of the torsion bar  106  where the cam follower  104  is mounted. In the embodiment shown in  FIG. 2 , the rotational force applied by the cam follower  104  is in a clockwise direction around the axis of the torsion bar  106 , as evidenced by arrow  107 . The anchor arm  110  provides a brace to prevent the torsion bar  106  from untwisting at the second end  112  thereof and releasing the torque built up in the torsion bar  106  by rotation of the cam follower  104 . 
   To anchor the torsion bar  106 , the cam follower  104  and anchor arm  110  mounted thereon to the bed platform  202 , a pair of mounting blocks  114 ,  115  and a mounting plate  116  are fit onto the cam follower  104  and the anchor arm  110 , respectively, and generally surround the torsion bar  106  through central holes  117  and  119  therein, as seen in  FIG. 3 . Referring to  FIG. 3 , the mounting blocks  114 ,  115  are preferably mirror-images of one another and have abutting mating surfaces  118  and  123  respectively. Bores, e.g. bore  120  and  121 , extend laterally through the mounting blocks  114 ,  115  through which fasteners (not shown) may be inserted to secure the blocks  114 ,  115  together and to secure blocks  114 ,  115  to the bed platform  202 , as explained more fully herein. In this way, the mounting blocks  114 ,  115  laterally sandwich a base  122  of the cam follower  104  therebetween while circumferentially surrounding bosses, e.g. boss  124 , of the base  122  through which the torsion bar  106  first end  108  extends. Similarly, the mounting plate  116  is configured to circumferentially surround a boss  126  of the anchor arm  110  through which the torsion bar  106  second end  112  extends. Bores, e.g. bore  128 , extend laterally through the mounting plate  116  through which fasteners (not shown) extend to secure the plate  116  to the bed platform  202 . Additionally, sleeve bearings e.g. bearings  130  and  131 , are press fit into the central holes, e.g. central hole  117 , of the mounting blocks  114 ,  115  and the central hole  119  of mounting plate  116  respectively, and are configured to surround the bosses  124 ,  126  to carry the torsional load on the cam follower  104  and the anchor arm  110  while allowing relatively free rotation of the follower  104  and arm  110  with respect to the blocks  114 ,  115  and the plate  116 , respectively. 
   As best seen in  FIG. 3 , the torsion bar or rod  106  is preferably formed by affixing multiple elongate hexagonal rods  132  together along longitudinal surfaces thereof such that each rod contacts at least two other rods. Three hexagonal rods  132  are shown in the embodiment of  FIG. 3 , but any number could be used as a matter of design choice depending on the desired strength and torsional rigidity of the torsion bar  106 , as well as the force necessary to lift and rotate the bed deck  200  ( FIG. 5 ) hingedly mounted with the bed platform  202 . The bosses  124 ,  126  of the mounting blocks  114 ,  115  and the mounting plate  116 , respectively, are shaped with a cross-section configured to accept the torsion bar  106 . 
   The cam follower  104  has a pair of flanged ears  135  and  137  on an end opposite of the base  122 , and a roller  136  rotatably mounted with the ears  135 ,  137 . The roller  136  allows the cam follower  104  to pass along the engaging surface  138  ( FIG. 4 ) of the cam  102  ( FIG. 4 ) with minimal friction while transferring the torsional load generated by the torsion bar  106  as a point load onto the cam  102 .  FIG. 4  shows one embodiment of the cam  102 . The engaging surface  138  is formed by a central convex region  140  that transitions into a lower concave region  142  which terminates in a stop  144 . 
   As shown in  FIGS. 5 and 6 , the convex region  140  is contacted by the cam follower  104  when the bed deck  200  is in substantially the horizontal position overlying the recessed storage area  204  of the bed platform  202  and as the deck  200  rotates upward about a hinge  205  for a distance. With continued upward rotation of the bed deck  200 , the roller  136  of the cam follower  104  enters the concave region  142  and continues therein until reaching the stop  144 , as best seen in  FIG. 7 . The stop  144  forms the outer edge of the concave region  142 , a region  142  with a radius that lowers in value until the radius is as small as the radius of the roller  136 . Roller  136  is effectively locked from continuing down the engaging surface  138  ( FIG. 4 ), thereby affixing the upward rotation limit for the bed deck  200 . The cam  102  has generally two laterally extending bores  146  and  147 , best seen in  FIG. 4 , for mounting of the cam  102  with fasteners to a bracket  148  affixed to the bed deck  200 , as best seen in  FIGS. 5–7 . A flat upper surface  150  ( FIG. 4 ) of the cam  102  is mounted against the deck  200  to transfer the point load applied by the cam follower  104  to the deck  200 . 
   As best seen in  FIG. 7 , the anchor arm  110  has a lower surface  152  that contacts a force adjusting screw  154  and transfers the reactive torque at the second end  112  ( FIG. 2 ) of the torsion bar  106  ( FIG. 2 ) opposite of the torque on the cam follower  104  ( FIG. 2 ) to the screw  154 . The screw  154  is threadingly mounted to a brace or fixed bracket  156  on the bed platform  202  that is configured to spread the reactive torsion load in the torsion bar  106  across a reinforced surface area of the platform  202 . The screw  154  may be rotated to change the angle of the anchor arm  110  about the torsion bar axis  105  relative to the angle of the cam follower  104  about the torsion bar axis  105 , which increases or decreases—depending on the direction of screw  154  rotation—the force applied by the cam follower  104  to the cam  102 . 
     FIGS. 8 and 9  show views of one bed platform  202  with the deck  200  removed for better viewing of the lifting mechanism  100 . The mounting blocks, e.g. block  114  ( FIG. 8 ), and mounting plate  116  ( FIG. 9 ) may, in one embodiment, be attached with fasteners to dividers  208 ,  210 , respectively, extending orthogonally with respect to the torsion bar  106  across the base surface  206  of the bed platform  202 . 
     FIGS. 10 and 11  show close-up views of a section of  FIGS. 8 and 9 , respectively, where the lifting mechanism  100  is seen mounted to the bed platform  202 . In at least one embodiment, as shown in  FIG. 10 , a first C-shaped bracket  156  is affixed on edges thereof to a back wall  212  and the base surface  206  of the bed platform  202 , such that the mounting blocks  114 ,  115  may be mounted to the bracket  156  with fasteners through bores, e.g. bore  120  ( FIG. 3 ) in the blocks, e.g.  114 , between the bracket  156  and the divider  208 . Two additional mounting brackets  166  and  167  may be used to help secure cam follower  104  to bed platform  202 . Brackets  166 ,  167  have aligned bore holes  164  and  165  respectively. Likewise, as shown in  FIG. 11 , a second C-shaped bracket  158  is affixed to the surfaces of the bed platform  202  in substantially the same manner as the first bracket  156 , such that the mounting plate  116  may be mounted to the bracket  158  with fasteners through bores, e.g. bore hole  128  ( FIG. 3 ) in the plate  116  between the bracket  158  and the divider  210 . To further stabilize the first and second C-shaped brackets  156 ,  158 , a vertical brace  160  may be mounted to the base surface  206  to span the lateral dimension between the brackets  156 ,  158 . Also, a channel brace  162 , with a cross-section best seen in  FIG. 6 , may be mounted to the back wall  212  of the bed platform  202  to abut the top of the brackets  156 ,  158  and provide further stabilization thereof. 
   When initially loading the torsion bar  106  with the necessary torsion for lifting the bed deck  200 , the cam follower  104  should be secured in a “loaded” position. To accomplish this, a loading cam (not shown) with dimensions larger than the cam  102  is first mounted to the bed deck  200  which is mounted to the bed platform  202 . The bed deck  200  is then lowered to the horizontal position such that the weight of the bed deck  200  loads the bar  106  with torsion. Once the body or center section of the cam follower  104  passes below an axis  169  ( FIG. 10 ) formed between bores  164  and  165  of adjacent loading brackets  166  and  167  (the loading cam being shaped not to block this axis as it is contacting the cam follower roller  136 ), a pin  170  (shown in phantom in  FIG. 10 ) may be inserted through both bore holes  164 ,  165  to hold the loaded cam follower  104  in place. The bed deck  200  may then be lifted and the loading cam replaced with the cam  102  used for standard operation. At that point, the deck  200  is again lowered to the horizontal position, this time with the engaging surface  138  of the cam  102  contacting the cam follower roller  136 . Once contact is established and the load is taken off of the loading bracket pin  170 , the pin  170  can be removed and the bed deck  200  and bed platform  202  are ready for use. 
     FIG. 12  is a similar view as that of  FIG. 8 , but with the torsion bar  106 , the cam follower  104 , the anchor arm  110 , the mounting blocks  114 ,  115  and the mounting plate  116  removed. The position of the loading brackets  166 ,  167 , the C-shaped bracket  156 , the vertical brace  160 , and the channel brace  162  is best seen in relation to the overall configuration of the bed platform  202  in  FIG. 12 . 
   Observing the motion of the bed deck  200  in  FIGS. 5–7 , it can be appreciated that as the deck  200  is rotated upward from the horizontal position, the center of gravity CG of the deck  200  moves towards a vertical plane (not shown) or position substantially normal to surface  220 . Thus, less of a moment exists that must be overcome by the point load applied by the cam follower  104 . Consequently, when the deck  200  is at or near the horizontal position, the cam follower  104  is rotated to a lower position corresponding to increased torsion in the torsion bar  106 . As the deck  200  rotates upward,  FIGS. 6 and 7 , the cam follower  104  likewise rotates upward, because of the shape of the cam engaging surface  138 , thereby decreasing the torsion in the torsion bar  106 ; the decreased torsion is desired because of the lower moment needed to support the bed deck  200  at the rotated position in force equilibrium. If the cam engaging surface  138  is properly dimensioned, and the weight of the bed deck  200  is known, the point load applied to the deck  200  by the cam follower  104  will equal the moment produced by the deck  200 , hence force equilibrium, and the deck  200  can be suspended at any angle of rotation without having to hold or brace the deck  200 . Even if additional items are placed on the deck  200 , increasing the moment, if the weight of these items is small compared to the weight of the deck  200 , only a small lifting force will be necessary to lift the deck  200  and expose the recessed storage area  204 . 
   It should also be understood that the key lifting components of the lifting mechanism  100  may be reversed in position. In this arrangement, the torsion bar  106  is mounted on the undersurface of the bed deck  200  with the cam follower  104  and anchor arm  110  affixed on the bar  106  and facing a direction opposite of that shown in  FIGS. 8–11 . Likewise, the flat upper surface  150  of the cam  102  becomes a bottom surface mounted against the platform base surface  206  such that the cam  102  faces upward for engagement with the cam follower  104  facing downward. 
   Changes may be made in the above methods, devices and structures without departing from the scope hereof. It should thus be noted that the matter contained in the above description and/or shown in the accompanying drawings should be interpreted as illustrative and not in a limiting sense. The following claims are intended to cover all generic and specific features described herein, as well as all statements of the scope of the present method, device and structure, which, as a matter of language, might be said to fall therebetween.