US2681783A - Self-leveling device - Google Patents

Description

June 22, 1954' w. J. SMITH 2,681,783

SELFLEVELING DEVICE Filed 0st? 18, 1950 2 Shets-Sheet 1 2a 4/ INVENTORJ.

Mum JjWzm U5 BY QWQQM 2 Sheets-Sheet 2 Filed 001;. 18, 1950 I N VEN TOR. [MZQ'gpzJJma't/Z @MQ@M Patented June 22, 1954 UNITED STATES PATENT OFFICE SELF-LEVELING DEVICE William J. Smith, Oregon City, Oreg.

Application October 18, 1950, Serial No. 190,783

4 Claims. 1

This invention pertains to self-leveling devices, and relates particularly to the novel construction of a device by which to maintain objects mounted thereon in a horizontal plane when the device is mounted upon an unstable support.

It is a principal object of the present invention to provide a self-leveling device which is essentially a self-contained unit of but three cooperating parts which are caused to move freely with relation to each other in response to forces of gravity.

Another important object of this invention is the provision of a self-leveling device which operates to maintain an object mounted thereon in a horizontal plane but prevents horizontal rotation of the object.

A further object of this invention is to provide a self-leveling device of simplified and therefore economical construction and which is sturdily built yet delicately responsive to forces of gravity.

These and other objects and advantages of the present invention will appear from the following detailed description taken in connection with the accompanying drawings, in which:

Figure l is a perspective view of a self-levelin device embodying features of this invention, parts thereof being broken away to disclose details of construction;

Figure 2 is a sectional view taken through the center of the device shown in Figure 1;

Figure 3 is a sectional view taken along the line 3-3 on Figure 2;

Figure 4 is a sectional view of the self-leveling device similar to Figure 3 and showing the same mounted upon a boat;

Figure 5 is a sectional view similar to Figure 2 and showing the self-leveling device in operation upon an angularly disposed support;

Figure 6 is a sectional view similar to Figure 2 showing a modified form of self-leveling device embodying features of this invention; and

Figure 7 is a sectional view showing a still further modified form of self-leveling device embodying features of this invention, the same being shown in tilted position by dotted lines.

Stated briefly, the self-leveling device of the present invention comprises a hollow ball, a socket freely overriding the ball, and a counterweight suspended from the socket.

Referring particularly to Figures 1 to 6, inclusive; the self-leveling device is shown tocomprise a pedestal-type base I provided with spaced holes 2 for receiving bolts 3 or other fastening means by which the base may be secured to an unstable support. Examples of the latter may include the deck or other structural member of a boat or airplane.

Mounted upon the central column of the base I is a hollow ball which is formed of the lower semi-spherical section 6 and the upper complementary segment 5. Section 4 may be secured to the base by any of various conventional means well-known in the art, such as by the welding 5 shown in Figure 2. Alternatively, the base and section 4 may be formed as an integral unit, as shown in Figure 6. Section t and segment 5 are provided with complementary interengaging shoulders I along their abutting edges, as illustrated, and are there preferably secured together detachably by means of set screws 8 for purposes explained in detail hereinafter. Thus, the section 4 and segment 5 cooperate to form a hollow ball which is provided with a circular opening defined by the circumferential edge 9 disposed diametrically opposite the base I.

A substantially semi-spherical hollow socket Ill is arranged to override the hollow ball. In the embodiments illustrated in Figures 1 to 6, inclusive, the inner diameter of the socket is somewhat greater than the outer diameter of the ball in order to provide sufficient space therebetween for the ball bearings II and their retainer ring [2. The diameter of the bearing ring [2 is chosen, in the embodiments illustrated, so that the bearings are disposed substantially midway between the circumferential edge It of the socket l0 and the circumferential edge 9 of the ball segment 5, as best shown in Figures 2 and 6. In this manner the bearings may roll upon the adjacent surfaces of the segment 5 and socket It within the limits of said edges as the self-leveling device is actuated by movement of the unstable support.

Flexible circular washers l4 and i5 are secured in circumferential grooves adjacent the edges 9 and 53, respectively, for sliding contact with the adjacent surfaces of the socket Ill and segment 5, respectively. These washers function to prevent displacement of the bearing ring it and also to prevent entrance of dirt into the bearing area. If desired, the washers may be replaced by lugs l6 and I'll, as illustrated in Figure 6. These lugs are disposed at spaced intervals about the circumference of segment 5 and project from the outer surface of the latter adjacent edge 9 and from the inner surface of the socket it) adjacent edge It, respectively. The lugs function in manner similar to washers l4 and 15 to prevent displacement of the bearing ring 12.

It is to be noted here, with reference to Figures 2 and of the drawings, that by the illustrated use of the single ball bearing ring I2, only the outer surface of the ball segment 5 and the complementary inner surface area of the socket IE, i. e., the area disposed between the washers I5 and It in Figure 2, need be machined to provide smooth rolling surfaces for the ball bearings II. However, those skilled in the art will recognize that various other means and methods may be employed in substitution for the ball bearing arrangement described hereinbefore to promote maximum freedom of movement between the ball and socket. One alternative is described hereinafter with reference to Figure 7. Another alternative, not illustrated, is to provide a plurality of ball bearings mounted in circumferential grooves formed in the inner face of the socket It adjacent the edge I3 and in the outer face of segment 5 adjacent the edge 9.

Referring now particularly to Figures 2 and 6 of the drawings, a counterweight I8, preferably of solid construction and of heavy mass, issuspended within the hollow ball by means of a rod I9 secured at its lower end to the counterweight and at its upperend to the socket II]. In Figure 2 the upper end of rod I8 is reduced in diameter and projects through holes provided in the socket It! and a platform 29. The socket and platform are thus secured together by means It is to be observed that the counterweight is of substantially semi-spherical shape having a diameter slightly smaller than the inner diameter of the hollow ball. The counterweight is installed within theball section 4 before segment 5 is attached. The latter'is then mounted upon the section 4 and secured in place by set screws 8. The counterweight may be of any other shape desired, it being necessary only that it'b'e contained within the ball. The shape and size illustrated is preferred, however, in order to prevent undesirable movemcntof the counter weight within the ball.

In the embodiment illustrated in Figures 1 to 5, inclusive, provision is made to prevent axial rotation of theplatform 20 relative to the base I and hence relative to the unstable sup-port upon which the base I is mounted. This provision is afforded by the following means: A pair of pins 24 are arranged to extend radially outward from diametrically opposite sides of the counterweight I8. These pins project'along a line extending through the point which defines the center of rotation of the hollow ball and socket. The pins extend into guide slots 25 which are formed in the inner surfaces of the section It and segment 5. The width of these slots is substantially equal to the diameter of the pins 24, whereby to receive the latter freely for sliding and pivotal contact without permitting excessive lateral displacement of said pins. The slots'25 extend in a plane normal to the plane of the base I and are arranged atdiametrically' opposite sides of the hollow ball; The length of slots 25' is determined by the maximum angle through which the device is to operate effectively to maintain the platform 28 upon a horizontal plane. In the illustration, the device is constructed to operate effectively through approximately 88, i. e. to maintain the platform in a horizontal plane during tilting of the base I to approximately 44 in any direction from a vertical line. Accordingly, the arcuate length of slots 25 shown in the drawing is at least 88, measured radially from the center of the hollow ball;

It will be apparent to those skilled in the art that the effective maximum angle of operation of thepresent device is also determined by the size of the opening in the ball defined by the circumferential edge 9. Thus, in the foregoing illustration, the diameter of said opening is greater than about 88 by the diameter of the sup-porting rod I9.

The device illustrated in Figures 1 to 5, inclusive, operates to maintain the platform 28 ina horizontal plane" and to prevent horizontal rotation of the platform, as follows? Let it be assumed that the base I is tilted in the plane of the drawings from the position shown in Figure 2 to the position shown in Figure 5. During this tilting of the base, the pins 2 merely slide along the guide slots 25 because the latter are disposed in the same plane in which the base .I is being moved. Let it now be assumed that the'base I is tilted in a plane perpendicular to the plane of the drawing from either of the positions shown in Figures 2 and 5. During such tilting the pins'fi. pivot axially within the guide" slots 25 because said pins are positioned in line with the center of rotation of the hollow ball and the socket Ii). Thus, it is" apparerit that the tilting of base I in any direction within the limits defined by the opening in the hollow ball and by the length of slots 25 may be accommodated by the simultaneous axial rotation and longitudinal movement of pins 24 within the guide slots 25.

The interengagement of the pins and slots operates additionally 'to' prevent horizontal rotation of the platform 20-; This" feature affords particular utility of the device aboard a ship or boat for mounting a compass upon the platform 29. Referring toFigure 4 of the drawings, the cooperating guide slots 25 and pins 24' permit the boat 26' to roll and pitch in any direction without disturbing the horizontal position of a' compass mounted upon the platform 29. The slots and pins prevent horizontal rotation of the platform, however, and thus the compass is maintained in its required position relative to the longitudinal center line 2? of the boat. It will be understood that the pins 24' need not be arranged in line with the center line 21, as

shown, but may be disposed in any other position desired. It is preferred, in any case, to position the pins '24 and slot '25 in the line of direction in which abrupt movements of the unstable sup port most frequently occur. In this manner the shearing strains exerted upon the pins 24 are reduced to 'a' minimum. 7

The'modii'ication'illustrated in Figure 6 of the drawing differs in general construction from the device of Figures 1-5, inclusive, in the absence of the pins 2 5 and guide slots 25. Incidental differ ences reside in the manner of detachably mount ing the platform 20, as explained hereinbefore. and in the shape of the counterweight I8. In the latter instance, the counterweight comprises a substantially greater portion of asphere than does the counterweight previously described; The

shapes illustrated are merely suggestive of several, it being understood that the counterweight may comprise a complete sphere if desired.

The device shown in Figure 6 not only provides for the maintenance of the platform in a horizontal plane during movement of the base I, but also permits horizontal rotation of the platform. This latter motion is permitted because rotation of the counterweight about a vertical axis is not restricted by the pins 24 and registering slots 25 provided in the structure previously described. This feature affords utility of the device for various purposes such, for example, as a mounting for a deck chair, whereby to maintain the chair level during motion of the boat and also to permit the chair to swivel in a horizontal plane. On the other hand, if it is desired to restrict horizontal rotation of the chair, the device shown in Figures 1-5 of the drawings may be employed.

The modification shown in Figure 7 of the drawings differs primarily from the structures described hereinbefore in the arrangement of the counterweight. The device comprises a hollow spherical ball which is open at both upper and lower ends. The ball is mounted upon an enlarged cylindrical housing 3|, with the lower opening of the ball registering with a hole 32 provided in the housing. The ball is secured in place by such means as bolts 33 extending through the out-turned flange 34 defining the periphery of the lower opening of the ball. The housing 3i is in turn secured to a base 35 by means of bolts 36.

A substantially semi-spherical socket 31 having an inner diameter substantially equal to the outer diameter of the hollow ball 30 is arranged over the upper opening of the ball for sliding contact with the latter. The contacting surfaces of the ball and socket may be greased or otherwise treated to reduce friction and promote freedom of motion. Grease seals 38 and 39 may be provided adjacent the upper opening of the ball 38 and the circumferential edge of the socket 31, respectively, to retain the grease therebetween. Alternatively, the anti-friction ball bearing arrangment described hereinbefore may be employed if desired.

The socket 31 supports a platform 40 which is secured thereto by means of the nut 4| which is threaded onto the upper end of rod 42. This rod is secured to the socket 31 and depends therefrom through the hollow ball 30 and into the housing 3|. A counterweight 43 of substantial size and weight is mounted upon the lower end of rod 42. Thus, the counterweight is displaced a greater distance from the center 44 of the hollow ball than are the counterweights of the structures described hereinbefore. This latter construction is used to advantage for supporting objects of considerably greater weight upon the platform 40 than can be supported effectively upon the platform 20 of the previously described devices.

In order to prevent horizontal rotation of the platform 40 with respect to the housing 3 l means similar to the pins 24 and guide slots 25 previously described may be provided, as follows: An arm 45 is secured to rod 42 at the center 44 of the hollow ball 33. The arm extends perpendicularly to rod 42 and terminates at its ends adjacent the inner surface of the ball 33. Pins 46 are provided on the opposite ends of the arm 45 and they extend into the guide slots 41 formed at diametrically opposite sides of the hollow ball 30. The slots extend in a plane normal to the plane of base 35, in manner similar to slots 6 25 described hereinbefore. The length of slots 4! and the openings in the hollow ball 30 determine the angle through which the device will operate to maintain the platform 40 in a horizontal plane, as previously described.

It is to be understood that the arm 45, pins 45 and slots 41 need not be provided if restriction of horizontal rotation of the platform 40 is not desired. By elimination of these elements, the device operates in the manner of the device illustrated in Figure 6.

A ring of rubber 48 or other resilient material is preferably secured to the inner surface of the housing 3| in proper position for engaging the counterweight 43 when the housing is tilted to its maximum limits, as illustrated in dotted lines in Figure '7. This ring forms a cushion to absorb the shock of impact of the counterweight, whereby to decrease the sound of impact and to prevent damage to the housing.

It will be apparent to those skilled in the art that the ball 30 may be mounted directly upon an elevated base without the necessity of housing 3|, in which case the flange 34 constitutes a base for the device. For example, the ball may be secured to a floor and the rod and counterweight suspended below the floor to any distance. This may be desirable when a large object such as a table or bed is to be supported upon the socket 31.

It will be further apparent to those skilled in the art that various changes may be made in the structural details described hereinbefore and illustrated in the drawings without departing from the scope and spirit of the present invention. For example, the pins 24 or 45 may be formed as integral parts of the counterweight l8 or arm 45, respectively. In either case a ring of ball or roller bearings may be mounted upon the pins, if desired, to promote freedom of movement of the latter. Alternatively, each of the pins may comprise a roller or ball bearing mounted for rotation in a bracket or other support provided at the proper positions previously described.

'It will be apparent that the pins 24 may alternatively be secured to and project radially from diametrically opposite sides of the inner surface of socket ID to engage guide slots formed in the outer surface of the ball sections 4 and 5. The illustrated arrangement is preferred, however, because the parts are enclosed within the ball. In any case the pins function with the cooperating slots to interengage the ball and socket at points extending through the center of rotation of said ball and socket in such manner as to prevent relative rotation of said parts about a vertical axis.

These and other modifications may be made as desired. Accordingly, the foregoing description is intended merely as exemplifying and illustrating the features of the invention and is not to be considered in a limiting sense.

Having now described my invention and the manner in which the same may be used, what I claim as new and desire to secure by Letters Patent is:

1. A self-leveling device comprising, in c0mbination, a hollow ball having an enlarged opening therein, a base connected to the ball opposite said opening, a hollow socket overlying the ball for movement relative thereto, a counterweight suspended freely from the socket, said ball having guide means formed at diametrically opposite sides and extending in one plane only normal to the plane of the base, pin means mounted in fixed relation to the socket and projecting in diametrically opposite directions along one line only extending through the center of rotation of the ball and socket, said pin means slidably engaging the guide means for movement longitudinally along and for rotation axially with respect to the guide means, and means on the socket for mounting an object to be supported.

2. A self-leveling device comprising, in combination, a hollow hall having anenlarged opening therein, a base connected to theball oppositesaid opening, a hollow socket overlying the ball for movement relative thereto, a counterweight suspended freely from the socket and contained within the hollow ball, said ball having guide means extending in one plane only normal to the plane of the base, pin means mounted in fixed relation to the socket and projecting along one line only extending through the center of rota-- tion of the hall and socket, said pin means slidably engaging the guide means for movement longitudinally along and for rotation axially with respect to the guide means, and means on the socket for mounting an object to'be supported.

3. A self-leveling device comprising, in combination, a supported hollow ball having an enlarged opening therein, a hollow socket overlying the ball for movement relative thereto, the ball and socket having a common center of rotation, a counterweight suspended from the socket, in: terengaging pin and guide means disposed in fixed relation to the ball and socket, the guide means extending radially about the said common center of rotation in onevertical plane only, the pin means projecting along one line only extending through said common center of rotation and 8, slidably engaging the guide means, whereby the pin means may move longitudinally along'and-rotate axially with respect to the guide means.

4. A self-leveling device for supporting an article, comprising a supported hollow ball havingv an. enlarged top opening therein, guide means within the ball extending radially about the center of the ball in one vertical plane only, transverse support means within the ball, pin means on the ends of the transverse support means and projecting along one line only extending through the center of the ball and slidably engagingthe guide means, whereby the pin means may move longitudinally along androtate axially with respect to the guide meanavertical support means secured to the transverse support means and extending upwardly therefrom-through the opening in the ball for supporting an article, and counterweight means extending downwardly from the transverse support means below the line axis of the pin means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,168,727 Jenigar Jan. 18, 1916 1,260,181 Garnero Mar. 19, 1918 1,365,233 Earle Jan. 11, 1921' 1,569,325 Leib Jan. 12, 1926 1,623, l27' Manrock Apr. 5, I92

FOREIGN PATENTS Number Country Date 11,227 Great'Britain of 1891 387,530 France of 1 908

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