Abstract:
According to one embodiment of the present invention, a side rail is provided having a body selectably movable from a first up position to a second down position. Two parallel lever arms are also provided. The arms rotate over center when moving the body between the two positions. This increases the horizontal distance through which the side rail moves. A biasing mechanism can be provided to urge the side rail towards either the up or down position, and to bias away from an intermediate toggle position wherein the lever arms are vertical in a preferred embodiment. The biasing mechanism can include a cam and roller. A hard stop can be provided, whereby in the up position there is a strong component to prevent failure. A release lever is also provided. A person can actuate the release lever to move the side rail from the up position.

Description:
This United States utility patent application claims priority on and the benefit of provisional application 61/535,806 filed Sep. 16, 2011, the entire contents of which are hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a side rail that is selectably movable from a first up position over center to a second down position. 
     2. Description of the Related Art 
     Bed side rails have existed for many years. In a basic form, a side rail is permanently fixed to the side of a bed frame. The side rail acts to alert the person that they are nearing the end of the sleep surface. Side rails are also useful as an assist device or grab bar for stability and for making adjustments in positioning. Of course, there have been many improvements over the years. Some examples include: 
     U.S. Pat. No. (hereafter, “USPN”) 3,585,659 to Burst et al. is titled Safety Side Guard for Hospital Beds. It describes a generally rectangular safety side guard pivotally mounted upon the mattress frame of a hospital bed and movable around the pivotal mountings from an elevated guarding position to a lowered inoperative position. Stops are provided to limit movement of the guard into the positions and latch means are provided to secure the guard in an elevated position. 
     U.S. Pat. No. 4,747,171 to Einsele et al. is titled Hospital Bed Rail Assembly. This patent shows a hospital bed having a storable safety rail. The bed includes a frame having a pair of laterally extending slide tubes mounted thereto. A pair of mounting shafts are positioned within the tubes and secure the safety rail to the frame. A stop member is positioned near the inner end of at least one of the tubes. The mounting shaft includes a projection which abuts the stop member when in a first rotational position, but is able to pass thereby when in a second rotational position. The stop member preferably includes an inclined surface opposing the inner end of the slide tube to urge the projection, and therefore the rail, outwardly as the mounting shafts rotate to move the rail to the raised position. A retraction spring is provided for urging the safety rail towards the bed frame while in the lowered position. The safety rail also includes a brake mechanism to resist the gravitational forces urging it downwardly from the raised position. 
     U.S. Pat. No. 6,389,622 to Her et al. is titled Hospital Bed. It describes a bed frame having a bed frame, a bed platform, a front plate, a distal plate, and two separate siderails at each side. The bed platform is structured by plurality of plates made by injecting plastics from a mold and serving to enhance the structure. The elevation angle of the bed platform can be adjusted by a driving device. Each of the siderails can be lifted or descended so that the patient can get on or off the bed conveniently. The outer side of each siderail is installed with at least one inner concave groove for fingers insertion when pull or push the siderails for safely purpose. Inner side of one siderail is installed with a motor controller to drive the driving device. The design will prevent the event of losing or destroying since it is fixed at a proper place. Besides, lower corners of the front and distal plates are installed with an impact-proof head to prevent the patient or others from being harmed by the corners. In particular, movable clamping pieces comprising a fixing seat, a pressing plate, a movable rear clamping plate, and a tightening block, are preset to the front plate and distal plate. With the special connection of the movable clamping pieces, the front plate and distal plate can be assembled or detached conveniently and easily. 
     U.S. Pat. No. 7,591,034 to Kramer et al. is titled Apparatus and Method for Closing Hospital Bed Gaps. It shows a patient support including a frame, a mattress supported by the frame, and a set of siderails configured to block egress of a patient from the patient support. The siderails are configured to reduce gaps defined between the siderails and the other components of the patient support. 
     While each of these examples show devices that may work well for their intended purposes, none show a biasing mechanism useful to bias the siderail towards either the up or down position. 
     Further, none teach that going over center can increase the horizontal movement of the side rail in proportion to a net change in vertical position. 
     Still further, none show the use of hard stops in the up position to provide a strong structure to prevent failure. 
     Still further, none show a release lever that acts in addition to a fixed stop in an up position. 
     Thus there exists a need for a side rail that solves these and other problems. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present invention, a side rail is provided having a body selectably movable from a first up position to a second down position. Two parallel lever arms are also provided. The arms rotate over center when moving the body between the two positions. This increases the horizontal distance through which the side rail moves. A biasing mechanism can be provided to urge the side rail towards either the up or down position, and to bias away from an intermediate toggle position wherein the lever arms are vertical in a preferred embodiment. The biasing mechanism can include a cam and roller. A hard stop can be provided, whereby in the up position there is a strong component to prevent failure. A release lever is also provided. A person can actuate the release lever to move the side rail from the up position. 
     According to one advantage of the present invention, a biasing mechanism useful to bias the siderail towards either the up or down position is provided. The biasing mechanism in one embodiment can be a cam and roller. 
     According to another advantage of the present invention, the horizontal movement of the side rail in proportion to a change in vertical position is increased by the defined lever arm path which swings over center. This advantageously allows the side rail to be positioned remote from the head board in the up position to allow for increased performance, yet allows the side rail to be unobtrusively stored when in the down position. 
     According to a still further advantage of the present invention, a hard stop is provided in the up position to provide a strong structure to prevent failure of the side arm. A hard stop can also be provided in the down position. 
     According to a still further advantage of the present invention, a release lever that acts in addition to a fixed stop in an up position is provided. In this regard, the release lever must be actuated before the side rail can be moved from the up position. 
     Other advantages, benefits, and features of the present invention will become apparent to those skilled in the art upon reading the detailed description of the invention and studying the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a preferred embodiment of the present invention in an up position. 
         FIG. 2  is a side view similar to  FIG. 1 , but showing the embodiment in a toggle position. 
         FIG. 3  is a side view similar to  FIG. 1 , but showing the embodiment in a down position. 
         FIG. 4  is a cross-sectional view showing a preferred embodiment in the up position. 
         FIG. 5  is a cross-sectional view showing a preferred embodiment in the toggle position. 
         FIG. 6  is a cross-sectional view showing a preferred embodiment in the down position. 
         FIG. 7  is a cross-sectional view showing selected components of a preferred embodiment in the up position. 
         FIG. 8  is a cross-sectional view showing selected components of a preferred embodiment in the toggle position. 
         FIG. 9  is a cross-sectional view showing selected components of a preferred embodiment in the down position. 
         FIG. 10  is a schematic view of a preferred embodiment in the up position. 
         FIG. 11  is a schematic view of a preferred embodiment in the toggle position. 
         FIG. 12  is a schematic view of a preferred embodiment in the down position. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While the invention will be described in connection with one or more preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     Looking first at  FIGS. 1-3 , it is seen that a bed  5  with a deck  6  and a headboard  7  is provided. The specific structures of the bed and deck are not of particular importance to the present invention. It is, however, contemplated that the present invention is useful for many styles of beds including but not limited to Hi-Lo style beds. 
     A side rail  10  is removably connected to the deck  6  of the bed near the headboard  7 . The side rail  10  has a first end  11 , a second end  12 , a top  13  and a bottom  14 . The first end is the end that is closest to the headboard  7 . 
     In  FIG. 1 , the side rail  10  is shown in an up position. In  FIG. 2 , the side rail  10  is shown in a toggle position (described below). In  FIG. 3 , the side rail  10  is shown in the down position. In the up position, it is seen that the side rail  10  is sufficiently far from the headboard  7  whereby there is not an entrapment issue. In the low position, the side rail  10  is sufficiently close to the headboard whereby there is not an entrapment issue. This is accomplished as described below. 
     In one embodiment where a 76 inch bed is used, the distance between the headboard face and the first end  11  of the rail  10  is 9.5 inches in the up position, 5.5 inches in the toggle position, −1.0 inches in the near down position (block engaged) and −0.5 inches in the full down position (hard stop engaged). In this regard, it is appreciated that the side rail end  11  can pass beyond the face of the headboard during its swing to the down position in order to be unobtrusive. 
     In the down position, a person can be removed from the bed  5 , as the top  13  of the side rail  10  is approximately the same height as the height of a mattress (not shown). The side rail  10  can also be removed from the bed  5  to facilitate moving a person from the bed  5 . 
     Turning now to  FIGS. 4-9 , it is seen that the components of the side rail  10  are illustrated in several cross-sectional views ( FIGS. 4-6 ) and in the several isolation cross-sectional views ( FIGS. 7-9 ). 
     A body  20  is provided. The body can be a molded body made of plastic. Alternatively, it can be formed from other materials without departing from the broad aspects of the present invention. The body has an opening at the bottom, whereby an insert  30  with a housing  31  is received. The insert  30  can be made of metal or other materials. The insert aids in holding, maintaining and/or aligning many of the other components. 
     A first lever arm  40  is provided. The lever arm  40  has a first end  41  and a second end  43 . A pin  42  is at or near the first end  41 . A pin  44  is at or near the second end  43 . A plate  45  can be fixed relative the first lever arm  40 . The plate  45  can define a cam  46  having a peak  47  at one end. An ear is preferably at the second end of the plate. 
     A release  50  (or release lever) is also provided. The release lever removably engages with the ear  48  of the plate  45 . While shown to engage the ear  48  of the plate  45 , it is appreciated that the release could alternatively engage other portions of the side rail  10  without departing from the broad aspects of the present invention. 
     A cylinder  60  is received within the body  20 . The cylinder  60  can house a stop  61  and a spring  62 . The stop engages or acts against a first end of the spring. A roller  63  can act against a second end of the spring  62 . The spring biases the roller  63  away from the stop  61 . The roller  63  moves closer to the stop  61  under compression of the spring  62 . 
     It is appreciated that the cam of the lever arm  40  and the roller  63  and spring  62  form a biasing assembly. In this regard, the peak  47  of the cam  46  acting against the roller  63  defines the toggle point. In this regard, the biasing mechanism is useful to bias or urge the side rail  10  to move away from the toggle point. It is further appreciated that while one embodiment of a biasing mechanism is illustrated, that other embodiments may be used (including but not limited to having the components be in reverse order) without departing from the broad aspects of the present invention. 
     A second lever arm  70  is also illustrated. The lever arm  70  has a first end  71  and a second end  73 . A pin  72  can be at or near the first end  71 . A pin  74  can be at or near the second end  73 . A link plate  75  is further provided and is preferably fixed with respect to the second lever arm  70 . 
     Pins  44  and  74  are useful to connect the side rail  10  to the deck  6 . The pins can be received within respective holes. Lanyards or other structures can be used to secure the pins  44  and  74  in place. Each pin  44  and  74  defines an axis of rotation, and the side rail swings or orbits about each respective axis or rotation 
     A link  80  is still further provided. The link  80  has opposed ends  81  and  82 . A top edge  83  is also provided. A first cutout  84  or relief is formed along the top  83  of the link near the first end  81 . A second cutout  85  or relief is formed along the top of the link near the second end  82 . A tab  86  projects upward from the top  83  of the link. The link  80  connects or links the first lever arm  40  and the second lever arm  70 . Specifically, the link is pivotally connected to both the plate  45  of the first lever arm  40  and the link plate  75  of the second lever arm  70 . The link swings an offset distance from pins  42  and  72 . The link  80  is preferably contained within the housing  31 . The link plate maintains the parallel orientation of the lever arms  40  and  70  enabling them to act in tandem. It is also appreciated that since the link  80  maintains a parallel orientation of the levers  40  and  70 , that only a single biasing mechanism can be used. 
     An absorption member, such as a compressible block  90  is further provided. The absorption member can absorb energy to slow or soften an impact. The block can be a compressible block, made of rubber or a similar material. However, the block  90  can be made of other materials without departing from the broad aspects of the present invention. For example, a spring can be used without departing from the broad aspects of the present invention. Also, it is envisioned that a dampening member that works in a manner other than compression may be used without departing from the broad aspects of the present invention. In the preferred embodiment, the absorption member progressively compresses as additional loading is applied to it. 
     Looking now at  FIGS. 7-12 , a detailed illustration of each of the positions about a preferred orbital path is provided. It is appreciated that the lever arms  40  and  70  cause the body  20  to orbit about a path relative the respective lever arms ends that are pivotally connected to the bed  5 . 
     Specifically in  FIGS. 7 and 10 , the present invention is shown in the up position. It is understood that the up position is not the tallest position, as the body goes over center at the highest position in moving from the down position to the up position. To move from the up position, the body first moves vertically upwards (at least has a vertical component to the travel) towards the highest position. 
     In the up position, the peak  47  of the cam  46  is on the first side of the roller  63 . Also, the pin  44  engages the cutout  84  of the link  80 . This is a hard stop that prevents further rotational movement of the side rail. It is also seen that the block  80  engages the top edge  83  of the link. The release  50  engages the ear  48  of the link plate when the side rail  10  is placed in the up position. The lever can be released (for example by pivoting a release arm) to disengage the release  50  from the ear  48  of the plate  45  whereby the operator can move the side rail  10 . In the preferred embodiment, the up position occurs when the lever arms  40  and  70  are approximately 38.5 degrees beyond vertical. However, it is appreciated that the arms could be at other locations without departing from the broad aspects of the present invention. 
     Looking now specifically at  FIGS. 8 and 11 , it is seen that the present invention is shown in the toggle position. On each side of the toggle position, the side rail is biased towards being in the up position or the down position. The toggle position occurs when the peak  47  of the cam  46  engages the roller  63  to force maximum compression of spring  62 . In the preferred embodiment, this occurs when the lever arms are oriented generally vertically. However, it is understood that the toggle point could occur at other angular orientations as well without departing from the broad aspects of the present invention. 
     The biasing mechanism can apply a force from the toggle point throughout the entire swing to the up position. Alternatively, the biasing mechanism can apply a force for only a portion of the swing beyond when the lever arms are vertically oriented. 
     Likewise, the biasing mechanism can apply a force from the toggle point throughout the entire swing to the down position. Alternatively, the biasing mechanism can apply a force for only a portion of the swing beyond when the lever arms are vertically oriented. 
     In all, in the preferred embodiment, the biasing mechanism can apply a force upon the side rail through approximately a 77 degree range. However, this range can be enlarged or reduced, and can even be applied to different rotational degrees upon each side of the toggle point without departing from the broad aspects of the present invention. It is preferred that the biasing mechanism apply a force a sufficient angular distance until it is highly likely that gravity alone will move the side rail to either the up or down position. 
     Looking now specifically at  FIGS. 9 and 12 , it is seen that the present invention is shown in a down position. In the down position, the peak  47  of the cam  46  is on the second side of the roller  63 . The block  90  first engages the tab  86  of the link  80 . Since the block is compressible, it softens the stopping of the side rail as it swings to the low or down position. Pin  74  can engage cutout  85  of the link  80  to form a hard stop (if the absorption member is compressed far enough), which prevents further rotational movement of the side rail  10 . It is further appreciated that the block can contact anywhere on the link (even if the link does not have a tab) without departing from the broad aspects of the present invention. 
     It is appreciated that while several hard stop embodiments are illustrated, that other structures could be used without departing from the broad aspects of the present invention. 
     Thus it is apparent that there has been provided, in accordance with the invention, a height adjustable apparatus that fully satisfies the objects, aims and advantages as set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.