with reference to the drawing figures , and initially to fig1 , a cradle or bassinet 10 , in general terms , has a main body 12 for holding the infant , and has a pair of curved rockers or rocker bases 14 . there are legs 16 that are affixed into the bases 14 , and these rise up from the rocker bases to support the body 12 . the curved lower side of each rocker base 14 has a curvature radius that allows at least a limited amount of rocking motion . here , the bases are disposed transversely , so the rocking is along the longitudinal or roll axis , but in other versions the rockers can be disposed along the fore - and - aft direction , so that rocking occurs on the transverse or pitch axis . an automatic rocking device 20 according to this invention is shown attached to one of the rocker bases 14 at an anchor point that is at or near one of the bassinet legs 16 . the rocking device 20 has a main body or housing 22 , depicted in this embodiment as an elongated generally flat member , and which has four legs 24 , one at each corner , that rest on the floor , straddling the rocker base 14 , to support the housing at a small distance above the rocker base 14 . each support leg has an inner slide 26 that can be extended out to adjust the length of the support leg 24 . in this example , each leg 24 has an engaging detent 28 , in the form of a spring - loaded button , to hold the leg in the selected elevated position . at the lower end of each leg 24 is a foot member 30 , with a resilient pad 32 of rubber or soft pliable plastic material . the pads 32 contact the floor , and these provide friction to help keep the device 20 in place on the floor . a u - shaped recess 36 is provided at one end of the housing 22 , and permits that end of the housing to extend at least partly around the associated bassinet leg 16 . a reciprocating rod 38 projects downward through an opening in the lower side of the housing 22 and attaches to a clamping device that is affixed onto the anchor point on the rocker base 14 . in this example , the clamping device includes a flexible strap 40 that wraps over the rocker base , and grommets at the end of the strap fit onto a hook at the lower end of the reciprocating rod 38 . in this embodiment , a strip 42 of a hook - loop material , e . g ., velcro is sewn onto the inner or rocker - facing surface of the strap 40 . favorably , this can be the loop material , and one or more patches 44 of the corresponding hook material can be affixed onto the sides of the rocker base at the anchor point . a motorized reciprocating mechanism 50 contained within the housing 22 of the device imparts a rhythmic up - and - down oscillatory motion onto the reciprocating rod 38 . this mechanism 50 can be implemented as a battery - operated dc motor drive , as illustrated schematically in fig3 . here , the reciprocating mechanism includes a dc motor 52 , receiving power from a source 54 of battery power , which is here represented as a battery but could be implemented with an external source of low - voltage electric power . the battery power is supplied to a control circuit 56 , e . g ., a speed control , which may have an associated on - off switch 58 and a speed control selector 60 . here the latter selector 60 is represented schematically as a variable resistance or potentiometer , but in practical implementations this could be a digital control that would change motor speeds incrementally up or down . in fig1 , the on - off switch 58 and speed control selector 60 are shown implemented as push buttons on the top of the rocking device housing 22 . the shaft of the motor 52 is coupled to a worm drive 62 , namely a worm screw 64 that engages the teeth of an associated worm gear or worm wheel 66 . the worm wheel 66 in turn rotates a crank mechanism 68 , and the upper end of the reciprocating rod 38 is attached onto a crank pin on the crank mechanism . the worm drive 62 serves as a compact and effective transmission for providing low speed oscillatory motion with sufficient torque for the rod 38 to lift and lower the anchor point of the associated rocker base 14 . the reciprocating rod 38 and strap 40 gently pull up on the rocker base to lift is a suitable distance , and then gently lower the rocker base , effecting a gentle , comforting rocking motion that is satisfying to the infant that is placed in the bassinet 10 . the reciprocating rod can be implemented as a two - piece threaded rod , so that its length can be adjusted by twisting its lower end to lengthen or shorten it , as needed . in some embodiments , the throw or stroke of the crank 68 may be adjustable to achieve a desired amount or rocking motion . the rocking device 20 of this invention has its non - moving feet 30 holding steady onto the floor of the room on either side of the rocker bar or rocker base 14 , and the reciprocating mechanism and reciprocating rod 38 simply raise and lower the rocker base at the anchor point . this motion produces far less travel or “ walking ” of the bassinet or cradle than do the devices of the prior art that push intermittently up and down against the floor , so with this device the bassinet or cradle is much more likely to remain at the same spot . the rocking device can be used with any existing rocking bassinet or cradle , as the device 20 rests on the floor and only connection that needs to be made to the cradle is to attach the patch 44 of velcro or other hook - and - loop material at the anchor point and to wrap the strap 40 around the rocker base at that point . these patches of hook - and - loop material are typically provided with an adhesive backing , and are quickly installed without difficulty . the battery - operated device , as shown and described , is preferred , but a wind - up spring motor - powered drive could be employed in some cases . an alternative embodiment shown in fig4 and 5 is a rocker device having a housing 120 that is integrated into the rocker base 14 . this embodiment employs a rotating arm as in the first embodiment , with the leg fully housed so that the portions of the housing 120 overhang the sides of the rocker base . various methods may create up and down motion . in this version , adjustable length leg or legs 130 , positioned on one or both sides , have their upper or distal ends attached to a rotary drive 140 within the housing . the leg or legs 130 swing up and lock into place when not needed , and can be moved down for use in rocking the bassinet . a speed knob 158 and timer knob 160 are positioned on the top of the housing . while the present invention has been described with reference to several specific preferred embodiments , it should be understood that the invention is not limited to those precise embodiments . rather , many modifications and variations would present themselves to persons skilled in the art without departure from the scope and spirit of this invention , as defined in the appended claims .
an automatic bassinet rocking device imparts a rocking motion to a bassinet or rocking crib . a housing is supported above the rocker base of the bassinet on adjustable legs so that the device straddles the curved rocking base . a reciprocating rod descends from the housing and attaches to a strap or clamp at an anchor point on the rocker base . an oscillatory drive inside the housing imparts a reciprocating motion via the reciprocating rod onto the rocker base .