US2509796A - Swinging seesaw - Google Patents

Description

May 3, 1950 E. .c. BAILEY 2,509,796

swmcmc SEESAW Filed Jan. 7, 1946 Patented May 30, 1950 UNITED STATES PATENT OFFICE 8 Claims.

This invention relates to swinging seats and more particularly in its primary aspect to recreational apparatus of the class known as counter-balanced or single-occupant seesaws. As is implied from the name, such devices customarily differ from the ordinary, twin-occupant seesaw in having counter-balancing means in one form or another which takes the place of one of the occupants and enables a single rider to enjoy the physical and psychological benefits of seesaw exercise.

Such devices include small teeter-boards in which the riders weight is balanced by a coil spring through a lever and hobby horses or bouncers in which an upwardly slanting, fiat spring is flexed as the rider moves up and down. Although wide variations in individual design are known to the art, such devices as a class appear to have at least one feature in common, viz: the rider moves simply up and down in a vertical plane, although he may vary somewhat the amplitude of his movement. As a result of this limitation, the child soon loses interest in his toy and the older the child the earlier is this inevitable result. Generally, such devices therefore, are manufactured in sizes suited only to young children and are constructed with only a relatively slight spring adjustment so that the toy must be laid aside as the child grows older.

In my co-pending application Serial No. 517,694 filed January 10, 1944, which has matured into Patent No. 2,457,627, there is disclosed a swinging seesaw in which the rider is not limited to moving simply up and down but may execute, if he so desires, a variety of movement. More specifically, he may swing from side to side as well as up and down or may describe a path having continually varying horizontal and vertical components of motion. The oscillatory system of which the seat for the rider is a part has a central position of stability when the rider is motionless in the seat. A slight shift of the riders body, however, will start the system into oscillation. The path of the oscillation is determined by the impetus and direction, but most of all by the timing of this shift and the subsequent movements of the rider with the natural period of oscillation of the system. In addition to vertical and lateral movement of the seat there is also a banking or twisting of the latter as it moves to its laterally displaced position. The seat is mounted at one end of an elongated member having its other end connected to the apical portion of a V-type base for the device and an intermediate portion thereof suspended from an inverted, V-type frame whose lower ends are rigidly united to the spaced portions of the base.

In use the invention of my co-pending application has been generally satisfactory. The V-type 5 frame, however, has been found as a result of extended observation, to possess certain inherent disadvantages, one of which is the latent risk to other children who feel impelled to assist the motion of the rider by grasping the elongated seat-carrier near the side members of the frame to give further impetus to the ride. In such maneuver there is the possibility that the hand of such child may be wedged between the seat carrier and the l-type frame and be injured in consequence. t was to increase the inherent safety of the swinging seesaw and to further simplify and thus lower its cost of manufacture that the present improvement was developed.

Accordingly, the invention of the present applioation constitutes an improvement over the subject matter of my co-pending application in various aspects which will be more specifically recited in the objects immediately following.

It is, therefore, an object of the present invention to provide a laterally banking, swinging seesaw in which the support for the seat-carrier thereof is disposed entirely below the latter thereby increasing the inherent safety of the device as will hereinafter be more fully described.

Another object of the invention is to provide a laterally banking, swinging seesaw in which the support for the seat-carrier is disposed in the vertica1 plane of the latter in its central position.

Another object of the invention is to provide a swinging seesaw of the character described in which maximum ease of oscillation is achieved by so proportioning the parts that the period of the lateral movement of the seat is approximately twice the period of the vertical movement.

Another object of the invention is to provide a device of the character described which permits the rider to have increased lateral freedom of movement.

Another object is to provide a supporting system for a swinging seat which provides resiliently counter-balanced, up and down movement for a rider thereon and concurrent, inherent axial twisting or banking about a single lower point of support therefor.

Other objects and advantages will be apparent from the description which follows and also from the drawing in which the single figure is a per- 3 spective view of a preferred form of my invention.

Referring now to the figure there is shown at l a base which may consist of a pair of elongated members 2, 3 which are preferably crossed as shown and reinforced by an end piece 4. In addition to the base referred to, the supporting means for the device also includes a vertical post 5 rigidly supported at the intersection of members 2 and 3 by suitable means such as fiange plate 6 secured to the crossed base members 2 and 3 by screws, for example, extending through apertures l in the plate. The upper end of post 5 terminates in a reduced portion 8 surmounted by a ball 9 which. is strongly made and preferably of solid material.

Elongated seat-carrying means indicated generally at H) preferably includes a central portion ma, disposed above the ball 9, a rearwardly depressed, seat-carrying portion iiib, and a forwardly depressed. spring-attached portion 18c which may be terminally flattened as shown. constituting elongated means it! are preferably two sections of pipe which are threaded into an integral member 25 as shown, the latter being provided with a conical, ball-receiving recess 9?) terminating in a skirt 22. The horizontal seat ll may be carried by a pair of parallel, downwardly extending supports 12, it connected to the pipe by suitable means Hi. Supports l2, l3 carry also a foot rest it and an upright post Hi for a hand grip ii. The forward end of the depressed portion We may be provided with longitudinally spaced apertures for the variable positioning of an eyebolt it retained by suitable means such as nut 19 and securely united to the upper end of a tension spring 253 the lower end of which is connected to the base as by means of a chain 2% and U-bolt 230 at a fixed point radially spaced from post 5.

It will be noted that the ball mounting of the elongated seat-carrying means it? of Fig. l permits the seat ii to move up and down or in the vertical plane of the post 5 laterally to either side of its stabilized, central position while simultaneously bankingabout an axis passing through the center of curvature of the ball 9 and parallel to the es tral portion 56a. The ball mounting, therefore, gives member Iii freedom about three mutually perpendicular axes, which results in a lateral. tilting or twisting of the seat as it moves away from the central position illustrated, in response to the shifting of a riders weight.

By suitably proportioning the parts the oscillatory system can be made quite sensitive so that only aslight shift of the rider will start the seat into its simultaneous up and down and lateral movements. As the greatest amplitude of this motion is attained, the rider from a point just above the base and laterally disposed from the central position by an angle of 45 degrees or more, swings upwardly in an are that reaches its zenith in the central position and then downwardly to an opposite position corresponding to the first point. Or the rider may swing upwardly into an extreme lateral position, so that in the next part of the cycle or rebound, the seat moves down through its low point centrally of the base and then up to an extreme lateral position opposite to the first. Or if less violent exercise is desired, a simple side to side movement without the up and down movement is easily accomplished. The up and down movement of prior art devices, of course, may be similarly performed if the rider wishes.

In the illustrated embodiment the spring 20 is shown as under tension and corresponds to the position of the seat II when a rider is seated thereon. I have found that the device is most sensitive to oscillation and hence gives the most satisfactory ride when the period of the lateral movement of the seat is approximately twice the period of the vertical movement. To adjust the device for a rider of a particular weight, therefore, the connection of spring 20 and portion lllc should be adjusted with the rider on the seat so that the latter is slightly above the horizontal. The distance of U-bolt 200 from the base of post 5 is then varied until the observed vertical and horizontal period of the seat with the rider thereon is that stated above. Obviously, the position of U-bolt 280 with respect to the base of post 5 may be varied by the use of various mechanical expedients. I have found in my experiments, however, that one adjustment of U-bolt 200 is adequate for riders varying in weight from 30 to pounds. The radial spacing of U-bolt 200 from the base of the post is essential to provide a centrally directed restorin moment to the swinging system whenever the seat is moved sideways, insuring thereby not only the banking action which has been described but also the building u of the oscillations.

By downwardly bending one or both terminal portions lilb, I00 of the elongated member I0 sufficiently to satisfy the requirement that the connection of the member Hi to the spring 20 be below a line passing through the seat and the ball 9, preferably by several inches, the seat is made completely stable against overturning while the rider is mounting or dismounting as well as throughout the ride. The marginal rim '22 of the integral member 2| together with theportion 3 of the posts serves to some extent as a stop to limit the lateral travel of the seat-carrier. It is preferred, however, to so proportion the base that the rider may swing through a very wide angle, say degrees, without risk of overturning. Thus, it may be found desirable to increase the effective lateral dimension of the base from that shown in Fig. l, as by lengthening and increasing the angle between the members 2, 3 or by adding lateral base members extending horizontally from the flange E5 and normal to the centra1 position of member ill. Also it will be apparent that while a ball support of substantial area has been shown by way of example, a very much smaller ball, say of one-half inch in diameter or even a point support would be perfectly satisfactory. Similarly,,any mechanical equivalent giving the member ID freedom about 3 mutually perpendicular axes such as a three-component universal joint would suffice.

The banking of the seat previously referred to is particularly important since it contributes materially to the approach of the system to a freely swinging pendulum and hence provides a device which is responsive to the slightest movements of a rider. This banking also adds to the feeling of security of the rider and encourages him to utilize the toys greatest lateral and vertical amplitude, since the farther he swings away from the central position the more firmly he is pressed against the seat. Thus, the oneness of rider and mount is a readily demonstrated fact which heightens the appeal of this device to all ages.

It will be apparent from the foregoing description that the present invention comprehends many feasible variations which still provide the vertical, lateral and freely banking motion of my invention. For example, it is obvious that a compression spring may be substituted for the tension spring 29 in case a supplemental chain or other safety device is not deemed a sufiicient safeguard against injury due to possible breakage of spring 28. Also a chain might be used at this point with the ball 9 mounted on a compression spring, for example, within the post 5. Likewise the elongated, seat-carrying member instead of being made of rigid material as shown may be flexible for a part or all of its extent if i desired. My invention cemprehends the use of such rider counterbalancing means singly or in any desired combination that attains the advantages of the invention. Also the seat H may be omitted and the foot rest l5 lowered and moved farther back so that the rider may stand on the latter and swing up and down and through all the variety of movement possible in the preferred form of the invention. Therefore, I do not desire to be limited to the precise forms of my invention illustrated but only as may be comprehended within the scope of the subjoined claims.

What I claim is:

1. A swinging seesaw comprising supporting means including a base and a vertical post rising therefrom, elongated seat-carrying means surmounting said post and having lateral, vertical, and axial freedom about the latter, and means connecting said seat-carrying means and a point on said supporting means which is fixed with respect to said post and radially spaced therefrom for limiting the freedom of said seat-carrying means, one at least of said means providing a resilient counterbalance for a rider carried by said seat-carrying means.

2. A swinging seesaw comprising supporting means including a base and a vertical post rising therefrom, elongated, vertically-offset seat-carrying means surmounting said post and having lateral, vertical and axial freedom about the latter, and resilient means connecting said seatcarrying means and a point on said supporting means which is fixed with respect to said post and spaced therefrom and lies within a vertical plane including said seat-carrying means and said post, said resilient means serving to counterbalance the weight of a rider carried by said seat-carrying means.

3. A swinging seesaw comprising supporting means including a base and a vertical .post rising therefrom, elongated seat-carrying means having terminal portions and a central portion disposed thereabove and surmounting said post and having lateral, vertical and axial freedom thereabout, and resilient means connecting one terminal portion of said seat-carrying means and a point on said supporting means which is fixed with respect to said post and radially spaced therefrom for stabilizing said seat-carrying means and also providing a resilient counterbalance for a rider carried thereby.

4. A swinging seesaw comprising supporting means including a base and a vertical post rising therefrom, elongated seat-carrying means having a central portion and at least one verticallyoifset terminal portion, said central portion surmounting said supporting means and having lateral, vertical and axial freedom. thereabout, and resilient means connecting a terminal portion of said seat-carrying means and a point on said supporting means which is fixed with respect to said post and radially spaced therefrom for providing a resilient counterbalance for a rider carried by said seat-carrying means and the offset of said terminal portion being sufficient to provide stability for the seat-carrying portion of said elongated means.

5. A swinging seesaw comprising a base, a vertical post rising from said base, elongated, vertically-offset seat-carrying means, a ball and socket joint including a small, rounded terminal portion and a surrounding cupped portion, said ball and socket joint connecting the upper end of said most and said seat-carrying means to provide for the latter, lateral, vertical and axial freedom about post, and resilient means connecting said seat-carrying means and a point on said base which is fixed with respect to said post and radially spaced therefrom for stabilizing said seat-carrying means in its central position and counter-balancing the weight of a rider carried thereby.

6. A swinging seesaw comprising a vertical post adapted to be mounted on a stationary base, vertically offset seat-carrying means having a ball and socket connection to said post to provide vertical movement and also lateral banking movement thereabout and resilient means adapted to connect said seat-carrying means and a point on said base which is fixed with respect to said post and radially spaced therefrom to provide a counterbalance for a rider carried by said seat-carrying means, the connection of said resilient means to said seat-carrying means being adjustable therealong to adapt the seesaw to riders of various weights.

'7. A supporting system for a swinging seat comprising supporting means including a base and a vertical post rising therefrom, elongated seat-carrying means having spaced terminal portions and an intermediate central portion surmounting said post and having freedom about three mutually perpendicular axes intersecting the axis of said post, and means connecting one of said terminal portions and a point on said supporting means which is fixed with respect to said post and radially spaced therefrom for limiting the freedom of said seat-carrying means, one at least of said means providing a resilient counterbalance for a rider carried by said seatcarrying means.

8. The combination as recited in claim '7' wherein said central portion is vertically disposed above at least one of said terminal portions.

EMMETT C. BAILEY.

REFERENCES CHTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 368,652 Class Aug. 23, 1887 935,854 Linerode Oct. 5, 1909 1,746,260 Kenney Feb. 11, 1930 1,832,755 Waddell Nov. 17, 1931 2,113,488 Milton et a1. Apr. 5, 1938

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