referring to fig1 of the drawings , there is shown the undercarriage 10 of a therapeutic treatment bed . in particular , the undercarriage includes a base 11 which is supported by wheel members 12 , 13 , 14 and 15 which allow the base and bed to be moved to a desired location . the wheel members may be of the locking type to retain the bed in a stationary position . the base 11 includes a plurality of longitudinally extending and transversely spaced beams 16 and 17 which are secured together by transverse beams 18 and 19 . the longitudinal beams 16 and 17 are spaced apart for a reason which will be explained hereinafter . a bed support means 20 is provided for supporting the patient support platform 54 . the bed support means 20 includes a plurality of longitudinally extending beams 21 , 22 , 23 , 24 , 25 and 26 . at the outer ends of the beams 21 and 22 is mounted an upright support post 28 . at the end of beams 25 and 26 is mounted another upright support post 27 . a pivot bearing 29 is secured to the upright post 27 . another pivot axis 30 is secured to the upright post 28 . patient support platform 54 which is shown in fig6 is mounted upon these pivot bearings . the patient support platform 54 is pivotally mounted on these pivot bearings 29 and 30 by pivot pins 59 and 58 respectively . as will be apparent , the beams 21 and 25 are connected by the beam 23 and the beams 22 and 26 are connected by the beam 24 . the transverse spacing between the beams 21 , 23 , 25 and 22 , 24 and 26 is such that they may be positioned between the beams 16 and 17 . the beams 23 and 24 may rest upon the transverse beams 18 and 19 in their lower most position . as will be apparent , the bed support means 20 may be lowered very close to the ground support through the unique arrangement in spacing of the beams and as a result of the lifting means described below . as shown in fig1 lifting means 31 and 32 are provided to raise and lower the bed support means 20 relative to the base 11 . lifting means 31 includes a power screw 33 which is driven by an electric motor 34 . the lifting means 32 is identical and includes a power screw 33a and an electric motor 34a . as will be apparent , each of the power screws may be retracted or extended upon actuation of the electric motors which are of the reversable type . the lifting means 31 as shown in fig1 - 4 includes a strap 35 which is secured to the beam 17 and another strap 35a secured to the beam 16 . these straps are secured to these beams by suitable means such as welding . a lever 36 is pivotally attached to the strap 35 . another lever 37 is pivotally attached to the other strap 35a . a lever 38 is pivotally attached to the lever 36 and another lever 39 is likewise pivotally attached to the lever 37 . the levers 38 and 39 are rigidly connected to a rotating shaft 40 by suitable means such as welding . the shaft 40 is rotatably mounted with support brackets 41 and 42 which are secured to the beam members 21 and 22 respectively . straps 43 and 44 are rigidly connected to the rotatably mounted shaft 40 . the power screw 33 is pivotally mounted with the straps 43 and 44 . since the other end of the power screw 33 is connected with the bed support means 20 actuation of the power screw means which results in its extension or retraction pivots the shaft 40 which in turn translates motion to the levers 36 , 37 , 38 and 39 . at the other end of the base 11 and bed support means 20 is another lifting means 32 . this lifting means includes straps 45 and 46 which are rigidly secured to the longitudinal beams 17 and 16 respectively . levers 47 and 48 are pivotally mounted with the straps 45 and 46 respectively . the opposite ends of the levers 47 and 48 are rigidly connected to rotating shaft 49 . the rotating shaft 49 is pivotally mounted with brackets 50 and 51 which are rigidly secured to beams 25 and 26 respectively . straps 52 and 53 are rigidly secured with the rotating shaft 49 to provide rotating motion thereto . one end of the power screw 33a is pivotally connected with the straps 52 and 53 and the other end is connected with the bed support means . accordingly , extension or retraction of the power screw 33a will result in pivoting of the shaft 49 and raising and lowering of the bed support means 20 . suitable control switches on a control panel ( not shown ) are provided to selectively and separately operate the lifting means 31 and 32 . accordingly , the bed support means 20 may be lowered , raised or tilted to provide a desired position for a patient support means which is mounted upon the pivot bearings 29 and 30 . the raising and lowering of the patient support means 20 is shown in fig2 and 4 . as shown in fig2 the bed support means 20 is in an intermediate position between its lower most and upper most positions . as shown in fig3 the power screws 33 and 33a are in their fully extended position which raises the bed support means 20 to its upper most position . as shown in fig4 the bed support means is tilted by extending the power screw 33a and retracting the power screw 33 . this is utilized to position the patient in an inclined position . as discussed above , the bed support means 20 may be lowered such that the beams 23 and 24 rest upon the beams 18 and 19 . in this position a patient ( not shown ) on a patient support mcans is closest to the ground support such that that person may be more easily removed from the bed . this is very useful with patients who as part of their treatment are removed from the bed . during removal they can be closely positioned to the ground support such that ease of entry and exit of the bed is made possible . this will facilitate in certain cases the transfer of the patient to a wheelchair or the like . such transfer may be difficult when the bed cannot be sufficiently lowered so that a person lying thereon can be easily removed and placed in a wheelchair by a single attendant . referring to fig6 of the invention , there is shown a patient support platform which may be rotatably mounted on bearings 29 and 30 . the patient support platform 54 includes a generally rectangular frame 55 connected to vertical posts 56 and 57 . pivot pins 58 and 59 are secured to the vertical posts 56 and 57 respectively and are adapted to be rotatably positioned upon the pivot bearings 29 and 30 for pivotally mounting the patient support platform 54 on the bed support means 20 . keel means 60 is connected to the vertical support post 56 to provide a counterbalance for the patient support platform . suitable weights may be positioned on the keel means 60 to prevent overturning of the bed which might cause a patient to fall therefrom . the patient support platform 54 includes a first support surface 61 which has a hatch means 62 . the hatch means 62 allows access to a patient from below the patient when a patient is not easily moved . a second support surface 63 is provided to complete the patient support platform . the second support surface 63 is pivotally mounted relative to the rectangular frame 55 so that it may be raised as shown in fig6 or lowered to a horizontal position whereby it is in the same plane as the first support surface 61 . the purpose for pivotally mounting the second support surface 63 is to allow it to be partially raised so that the patient may be raised and inclined in the bed . secured at one side of the frame 54 is a bracket 64 having a plurality of slots positioned there along . a similar bracket ( not shown ) is positioned opposite the bracket 64 . levers 66 and 69 are pivotally mounted at one end to the second support surface 63 and a bar 67 as secured at their other end to interconnect them . bar 67 extends beyond the outer sides of the levers 69 and 66 so that it may be selectively inserted into notches in the brackets such as notch 68 to retain the second support surface in a desired position and angle relative to the first support surface 61 . the second support surface 63 is fixedly mounted to frame member 69 so that pivoting of the second support surface 63 causes rotation of the frame member 69 . strap 70 is rigidly secured to the frame member 69 and a bifurcated bracket 71 is pivotally connected to the strap 70 . rod member 72 is connected to the bifurcated bracket 71 and also connected to sliding pin 72a . the pin 72a is slidably mounted in a sleeve 73 positioned in the vertical post 56 . when the patient support platform 54 is positioned on the bed support means 20 , pin 72 extends adjacent the upright post 28 when the upright post 28 and the vertical post 56 are aligned . when the patient support platform 52 is in its horizontal position and the second support surface 63 is in its raised position then the pin 72 is extended whereby it will be inserted in a sleeve 28a extending through the vertical post 28 to prevent rotation of the patient support platform 54 . this acts as a safety measure to prevent rotation of the bed when the back or second support surface 63 is in the raised position . secured with the bed support means 20 is a drive motor 74 ( fig1 and 5 ) which provides rotation to the patient support platform 24 so that it will oscillate in a predetermined arc . the drive motor 74 includes a reduction gear box 75 which has a rotating output shaft 75a as shown in fig5 . attached to the rotating output shaft 75a is a slip clutch 77 which includes journal 76 on which is rotatably mounted portion 76a of lever 78 . the slip clutch prevents damage to the motor 74 and gear box 75 when overloaded and is also used to determine the amount of counterbalancing weight added to the keel . as shown in fig5 and 5a , the shaft 76 is pivotally connected to journal 76a on lever 78 . as best shown in fig8 the lever 78 is connected to lever 79 by connecting means 80 . the lever 79 is in turn rotatably connected to pin 81 as best shown in fig5 . the pin 81 is secured with the patient support platform 54 spaced from the center of rotation of the pivot pin 59 . as will be apparent , rotation of the lever 77 will cause reciprocation of the lever 78 which motion will be translated to the lever 79 when the connecting means 80 rigidly connects the levers 78 and 79 in the position as shown in fig8 to provide oscillation of the patient support platform 54 . the arc in which the patient support platform 54 oscillates is determined by the position of the pin 81 relative to the pivot pin 59 . as shown in fig6 the pin 81 is eccentrically mounted about another pin 82 which is releasably secured in the pin support bracket 83 . as shown fig7 the pin support bracket 83 includes two portions 84 and 85 which compressably hold the pin 82 to prevent its rotation . this is achieved by a screw tightener 86 which may be used to clamp the two portions and prevent the pin 82 from rotating or to release the two portions and allow rotation of the pin 82 . rotation of the pin 82 changes the position of the pin 81 which is rotatably connected with the lever 79 . this effects the arc in which the patient support platform 54 rotates . as shown in fig7 secured to the end of the pin 82 opposite the pin 81 is an adjusting bracket 87 having a plurality of notches 88 , 89 , 90 and 91 . secured to the upper portion 83 is bifurcated bracket 92 through which extends a pin 93 . pivotally mounted with the pin 93 is a locking member 94 which may be selectively positioned in notches 88 , 89 , 90 or 91 . this is achieved by loosening the screw tightener 86 and rotating the pin 82 to position the notches so that the locking member 94 may be selectively positioned in the notch which is at the position of notch 90 as shown in fig7 . the connecting means 80 is best shown in fig8 , 10 , 11 and 12 . referring to fig9 the connecting means 80 includes a releasable locking means 95 which selectively engages and locks the levers 78 and 79 in the position shown in fig8 or releases them as shown in fig1 so that the lever 79 is not rigidly connected to the lever 78 . the purpose of the releasable locking means is to allow the patient support platform 54 to be disconnected from the drive motor 74 so that support platform 54 will oscillate independently of the drive motor 74 . in its engaged locked position , the lever 79 fits in a slot 96 ( fig1 ). slot 96 receives the lever 79 as shown in fig9 and 10 to rigidly lock them together . the releasable locking means 95 as best shown in fig1 includes an eye bolt 97 having threaded portion 97b which is connected to threaded portion 98b of end cap 98 which engages member 99 which is rigidly secured to the lever 79 . the reduced portion 98a of the end cap 98 extends through an aperture 100 in the member 99 . a sleeve 101 is rigidly secured with the lever 78 and extends through the aperture 102 in the lever 79 . lever 79 slides upon the sleeve 101 from its locked position as shown in fig9 and 10 to its released position as shown in fig1 . the eye bolt 97 extends through the sleeve 101 and through bracket 103 . the bracket 103 as shown in fig1 is rigidly secured to lever 78 and is bifurcated member with straps 104 and 105 . strap 105 includes a slot 106a and the strap 104 also includes an identical slot 106 . slots 106 and 106a slidably receive a pin 107 having apertures 107a . cotter keys 113 and 114 and washers 115 and 116 retain the pin 107 in position when it extends through slots 106 and 106a and apertures 109a , 97a and 109b . the releasing and engaging lever 108 includes a camming surface 109 and locking surfaces 109c , the purposes of which are more fully explained hereinafter . positioned on the eye bolt 97 is a washer 110 . a first spring member 111 is positioned about the eye bolt 97 and to engage bracket 103 and washer 110 to bias the washer 110 against the camming surface 109 . a second spring member 112 is positioned about the eye bolt 97 to engage the member 99 and the bracket 103 . as will be apparent , the spring 112 acts against the member 99 to bias the lever 79 to the position as shown in fig1 . spring 111 acts to move the lever 78 and 79 to their locking position as shown in fig9 and 10 . the springs 111 and 112 have preselected force values to maintain the releasable locking means 95 in its position as shown in fig9 when the releasing and engaging lever 108 is in its engaged setting and to allow release of the releasable locking means 95 when the lever 108 is moved to the releasing setting as shown in fig1 and 11 . however , the releasable locking means will not allow release of the lever 79 from the lever 78 until patient support platform 54 is in its substantially horizontal rest position and there are no frictional forces being applied to the levers 78 and 79 . this is achieved by carefully selecting the forces of the springs 111 and 112 as follows . when the lever 108 is in its engaged setting as shown in fig9 and the flat locking surface 109c forces the washer 110 against the spring 111 , the spring 111 applies a greater force than does the spring 112 . this acts to retain the levers 78 and 79 in engaged or the locked position as shown in fig9 . the flat locking surfaces 109c retains the lever 108 in its engaged position . when it is desired to release the lever 78 and 79 so that the bed will remain in a horizontal position , the lever 108 is moved to the releasing setting as shown in fig1 and 11 . in this case the camming surface 109 allows the washer 110 to be moved to the right as shown in fig1 and 11 to release some of the stored energy in the spring 111 . in this position , the spring 112 applies a greater force than does the spring 111 . however , the lever 79 is not released from the lever 78 due to the frictional forces between the contacting surfaces of the levers 78 and 79 . the frictional forces occur from the weight of the patient support platform 54 . accordingly , the levers 78 and 79 will not be released from each other as shown in fig1 until the patient support platform 54 reaches a substantially horizontal position and no force is being applied to the lever 78 by the lever 79 . this always occurs when the patient support platform 54 is in its substantially horizontal position . accordingly , the lever 109 may be released or engaged when the patient support platform is in any position but it will retain the levers 78 and 79 in their locked position as shown in fig1 until the bed reaches a substantially horizontal position where the spring 112 will cause the lever 79 to pop out of the slot 96 . thereafter reciprocation of the lever 78 will no longer apply any force to the lever 79 since lever 78 and 79 are allowed to rotate relative to each other about pin member 97 . when it is desired to reconnect the levers 78 and 79 to the locked position as shown in fig8 and 10 , the lever 108 is moved to its engaged setting as shown in fig9 . however , the lever 79 will not be positioned into the slot 96 until the levers 78 and 79 are properly aligned during the reciprocating stroke of the lever 78 . accordingly , the releasable locking means 95 can be set to automatically release the levers 78 and 79 and likewise automatically connect them at the horizontal position of the patient support platform when frictional forces are relieved . the operator can also relieve the friction force between the levers 78 and 79 and manually release or connect them at any position . without the releasable locking means 95 , it would be difficult to releasably connect the levers 78 and 79 and this generally would have to be done when the patient support platform 54 was in its substantially horizontal position . it should be understood that the lever 78 moves very slowly so this would require an attendant to wait until the levers 78 and 79 were properly aligned before they were released or reconnected . the releasable locking means 95 allows attendant to engage or disengage the lever 108 at any time so that the levers 78 and 79 will automatically be connected or disconnected as desired . a large amount of physical strength is not required to perform this task notwithstanding the great weight of the bed , particularly with the patient positioned thereon . although the invention has been described in conjunction with the foregoing specific embodiment , many alternatives , variations and modifications will be apparent to those of ordinary skill in the art . those alternatives , variations and modifications are intended to fall within the spirit and scope of the appended claims .
a therapeutic treatment table having a lifting mechanism to allow lowering of the therapeutic treatment table close to the ground support surface and having a releasable connecting means to automatically connect or release the oscillating means from the therapeutic treatment table and an adjusting means to vary the degree of oscillation of the therapeutic treatment table .