Abstract:
A portable baby chair 10 suspendable from the edge of an ordinary table 100 and which has spring biased pivoted locking bars 54, 56 on the chair&#39;s under table supports 20, 22 to engage the underside 99 of the table top and prevent the chair from slipping.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to baby chairs which are suspendable from a table edge, and which can be removed and folded when not in use. 
     2. Prior Art 
     Portable baby chairs which can be attached to the edge of an ordinary table are well known. A variety of designs have been proposed for such chairs, and features which have proved advantageous include a cantilever arrangement for holding the chair to the table, a rigid seat bottom and back for greater chair strength, and foldability when the chair is not in use. Chairs embodying these features are described in U.S. Pat. No. 2,707,987 to Gibson, U.S. Pat. No. 3,052,500 to Hyde, U.S. Pat. No. 3,059,965 to Fornetti, U.S. Pat. No. 3,133,760 to Robinson, and U.S. Pat. No. Des. 200,850 to Palmer. Although the cantilever design allows the chairs to be conveniently hooked onto and unhooked from a table edge, it suffers from depending on a child&#39;s weight to create the friction needed to hold the chair stable against the table. If the child does not sit still, the chair can work its way back until one or both arm rests slip from the table, endangering the child. Thus, there is a need for a portable baby chair which can be better secured to a table top. 
      SUMMARY OF THE INVENTION 
     It is therefore the primary object of this invention to provide a portable baby chair which can be more reliably secured to a table top than could previously known cantilever style chairs. Another object is to  provide a strong and stable chair which is convenient to use. This invention achieves these objects by providing a baby chair with a spring biased locking bar on each of the chair&#39;s under-table supports. The locking bars are pivoted at their lower ends to the supports. As the unfolded chair is slipped around the edge of a table top with the arm rests above and the supports below, the table top edge causes the bars to rotate backward against the spring force. The top ends of the bars, urged by their springs against the undersurface of the table, follow the pivoted bottom ends of the bars as the supports are swung under the table. Thus, the bars do not hinder hanging the chair from a table. However, once the chair is in place, pushing the chair away from the table causes the tops of the locking bars to dig in to the undersurface of the table and to hold the chair stationary. The locking bars are covered by gripping material for a better hold. When desired, the chair is easily removed from the table by grasping each of the bars and pulling it down from the table undersurface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the chair; 
     FIG. 2 is a side elevation of the chair showing how it is slipped around a table edge; 
     FIG. 3 is a side elevation detail of one of the locking bars; 
     FIG. 4 is a rear elevation of the chair; and 
     FIG. 5 is a perspective view showing the chair folded for storage. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, the baby chair 10 may be suspended from the edge of an ordinary table 100. Chair 10 comprises a rigid seat bottom 12 and a rigid seat back 14, both made of suitable material such as plywood and foam padding covered with wipe-clean plastic. A safety harness 16 made, for example, of nylon webbing with a buckle 17 insures that a child does not slip out of the chair, which is normally suspended several feet above a floor on the edge of table 100. Aside from seat bottom 12, back 14, harness 16, table grips 25, 27, 45, 47, 55, and 57, and pivot spacers 19, the rest of the chair is made of metal. A pair of under-table supports 20 and 22 extend from respective rear corners, along the sides, and past the front corners, of seat bottom 12, and turn upward to end in vertical table-abutting sections 24 and 26. Seat bottom 12 is fixedly attached to and supported by supports 20 and 22. Making supports 20 and 22 from a continuous piece of tubular metal including section 21 (FIG. 4) around the back increases the chair&#39;s strength and, in particular, helps keep it from twisting or tilting sideways. 
     A pair of plates 30 and 32 are fixed by rivets, for example, to seat back 14, and each extends forward in a vertical plane parallel to the sides of the chair. A U-shaped seat back reinforcement 15 (FIGS. 2 and 4) may be provided to strengthen the chair, in which case plates 30 and 32 are preferably attached to seat back 14 by way of rivets 18 through reinforcement 15. 
     A pair of arm rests 40 and 42 rotate relative to plates 30 and 32 by way of plate pivots 41 and 43 respectively. Arm rests 40 and 42 extend forwardly parallel to the side edges and past the front edge 13 of seat bottom 12 to end in table tangent sections 44 and 46. The arm rests 40 and 42 may also be connected in a continuous piece including section 48 as shown in FIG. 4. 
     Supports 20 and 22 are suspended from arm rests 40 and 42, respectively, by a back pair of vertical links 60 and 62 and by a front pair of vertical links 70 and 72, respectively. The links are connected to the arm rests by pivots 41, 43, 76 and 77, and to the supports by pivots 61, 63, 71 and 73. The pivot connections allow the chair to be folded for storage as in FIG. 5 with the arm rest 40, support 20, and links 60 and 70 (and of course the corresponding members on the hidden side) forming a parallelogram, and to be unfolded for use as in FIG. 1 with the named members more rectangularly disposed. 
     Diagonal links 64 and 65 help to reinforce chair 10 from being deformed by a child&#39;s weight, but otherwise do not constrain the chair&#39;s folding action. Rather, diagonal links 64 and 65 couple the tilt of seat back 14 to the shape of the parallelogram structure defined by front links 70, 72, rear links 60, 62, arms rests 40, 42 and under table supports 20, 22. Thus, as seat back 14 is moved towards or away from seat 60, 62, 70, 72 and supports 20, 22 to pivot corresponding amounts. See FIGS. 2 and 5. Diagonal link 64 is connected to plate 30 and to link 70 by pivots 34 and 74 respectively, and likewise diagonal link 65 is connected to plate 32 and to link 72 by pivots 35 and 75 respectively. 
     As shown in FIG. 2, chair 10 is unfolded for use and slipped around the edge of a table 100. Any ordinary table less than 2&#34; thick can be used without modification, although there must be adequate clearance for the child&#39;s legs between the seat front edge 13 and the lower corner and any panel (not shown) on table edge 102. A glass topped or otherwise fragile table may not be strong enough, and a pedestal table might tip over. The chair is suspended by cantilever action when a child&#39;s weight pulls the arm rest tangent sections 44 and 46 down on points near the edge 102 of table top 101, and the table-abutting sections 24 and 26 of the support bars bear upward on the underside 99 of the table at points further from table edge 102 than the points reached by arm rest sections 44 and 46. 
     Locking bars 54 and 56 are attached to supports 20 and 22 by pivots 50 and 52 respectively. Bars 54 and 56 pivot within the limits imposed by bar angles 58 and 59. Biasing springs 51 and 53 urge the bars towards the table abutting ends 24 and 26 of the supports. When the seat is being installed on a table top 100, table edge 102 pushes locking bars 54 and 56 against springs 51 and 53. Obtuse angle theta (FIG. 3) allows the bars to slide by the under surface 99 of the table. However, once the chair is in place, springs 51 and 53 maintain the locking bars against the table, and pushing or pulling chair 10 away from table 100 causes the locking bars 54 and 56 to dig in to the table underside 99 at acute angle phi. 
     To help keep chair 10 stationary relative to table 100, while protecting table surfaces from being scratched, non-abrasive frictional coverings such as plastic cups 25 and 27, 45 and 47, and 55 and 57 are provided respectively for the ends of table abutting sections 24 and 26, arm rest tangent sections 44 and 46, and locking bars 54 and 56. 
     When a chair 100 is in use, the child&#39;s weight keeps the chair unfolded to the limit imposed by arm rest stops 31 and 33, which are part of, and at right angles to the rest of, plates 30 and 32 respectively. A safety pin 36, shown locked in FIG. 1 and unlocked in FIG. 5, insures that the chair is locked open. Safety pin 36 has a pull knob from which a shaft extends through a hole in arm rest 40 and into a hole 37 in plate 30. A spring (not shown) inside the arm rest holds the pin in plate hole 37 until the shaft is retracted by pulling the knob. 
     Details have been disclosed to illustrate the invention in a preferred embodiment of which adaptions and modifications within the spirit and scope of the invention will occur to those skilled in the art. The scope of the invention is limited only by the following claims.