US3420187A

US3420187A - Turntable with short radius roller ring

Info

Publication number: US3420187A
Application number: US626559A
Authority: US
Inventors: David Bruce Johnson; Daniel Moro; Nicholas G Cristy
Original assignee: Macton Machinery Co Inc
Current assignee: Macton Machinery Co Inc
Priority date: 1967-03-28
Filing date: 1967-03-28
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07

Description

Jan. 7, 1969 0. B. JOHNSON ETAL 3,420,187

TURNTABLE WITH SHORT RADIUS ROLLER RING Filed March 28, 1967 ATTORNEYS.,

United States Patent 11 Claims ABSTRACT OF THE DISCLOSURE This invention relates to turntables of a type that are used in automobile showrooms, railroad stations and at other locations for advertising displays of automobiles or other items. More particularly, the invention relates to turntables that have a short-radius circle for the supporting rollers and that have the turntable beyond the roller circle of cantilever construction. a

It is an object of the invention to provide an improved construction for turntables that have small roller circles. While turntables having large roller circles usually have only about of the radius of the turntable beyond the supporting rollers, a turntable with a small roller circle has most of its radius beyond the supporting rollers. It will be understood that large and small, as used herein, have nothing to do with dimensions, but with proportions. For purposes of the description of this invention, the expression small roller circle means a roller circle having a diameter less than half of the diameter of the turntable and these small roller circles involve problems different from those of turntables having larger roller circles.

A turntable having a large roller circle has supports at three or four locations across the diameter of the turntable, whereas the smaller roller circle turntable has supports at only two locations, though the diameter of the turntable may be just as large in one case as the other. These differences will be explained in connection with the drawing.

All else equal, the loading of the individual rollers of a small roller circle turntable is substantially higher; partly because there are fewer supports across the diameter of the turntable, but also because there are fewer rollers to take the load in a smaller circle than in a large one. Therefore, the presure of each roller against the bottom of the turntable is greater.

Because of this greater pressure, more wear is to be expected, and actually the wear is greatly increased because of the reduced circumference of the surface of the turntable that contacts with the rollers; that is, the wear is concentrated in a shorter length of arcuate surface of the turntable.

There is another factor, however, that tends to produce an even greater effect in the wear, and this is the alignment. The supporting rollers for a turntable are tapered and have their axes of rotation inclined so that the apex of the conical surface is on the axis of rotation of the turntable and at the level of the plane of the bottom surface of the turntable that contacts with the rollers. Precise alignment is difficult to obtain, and because of the reduced spacing of the rollers from the axis of rotation of the turntable the same actual dimensional misalignment is proportionately greater in a small circle than in a large one because it is a larger percentage of the angle.

It is another object of this invention to provide a small roller circle turntable with rollers supported with sloping axes in alignment both horizontally and vertically with the same point on the axis of rotation of the turntable,

and to provide an improved construction for replacing worn or defective rollers without disturbing the alignment of the roller supports and Without requiring any realignment for a new roller.

This invention reduces the cost of production of turntables of the character indicated, reduces wear, facilitates the replacement of rollers, and reduces maintenance expense.

Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like reference characters indicate corresponding parts in all the views:

FIGURE 1 is a diagrammatic view showing the construction of a turntable having a large roller circle;

FIGURE 2 is a diagrammatic view, similar to FIG- URE l, but showing a turntable having a small roller circle;

FIGURE 3 is an isometric view showing a turntable made in accordance with this invention and showing the way in which an automobile is located on the turntable;

FIGURE 4 is an exploded view of the turntable shown in FIGURE 3, the parts being turned to different positions;

FIGURE 5 is a greatly enlarged, fragmentary, sectional view of a portion of the turntable and one of the supporting brackets shown in FIGURE 4; and

FIGURE 6 is a side elevation of the roller support shown in FIGURE 5.

FIGURE 1 shows a turntable 10 supported at the center by a post 12 and supported at angularly spaced locations near its periphery by rollers 14. This turntable has three supports and the rollers 14 are located around a roller circle which is at a distance from the center equal to of the radius of the turntable. The peripheral portion of the turntable beyond the circle of rollers 14 has cantilever support that is preferably not over 20% of the radial extent of the turntable.

Often the turntable is supported by another circle of rollers, similar to the rollers 14 but located much closer to the center of rotation and these inner rollers may take the place of the support provided by the post .12 in FIG- URE 1. If they do, then the turntable is supported at four locations across its diameter instead of at three, as in FIGURE 1.

FIGURE 2 shows a turntable 20 which has a center post 22 and supporting rollers 24. The supporting rollers 24 are located at angularly spaced regions around a roller circle which has a radius very much smaller than that of the turntable 20. In the construction illustrated, the radius of the roller circle for the rollers 24 is only 30% of the radius of the turntable 20, and thus 70% of the turntable 20 is a cantilever construction. With the rollers 24 located close to the center of rotation, it is not necessary to have the post 22 support the turntable, and in the construction shown the post 22 merely holds the turntable against transverse movement without providing any support.

FIGURE 3 shows the turntable 20 which includes a hub portion 28 with arms 31 and 32 extending from opposite sides of the hub portion 28 and for substantial distances beyond the hub portion. There is a front cross arm 33 connected with the outer end portion of the arm 32 and there is a corresponding rear cross arm 34 connected near the rearward end of the arm 31.

These cross arms 33 and 34 hold small platforms 36 on which the wheels of an automobile can be located. FIGURE 3 shows an automobile in phantom, and this automobile is designated by the reference character 40.

The turntable 20 can be designed for a particular make and model of automobile and in such case, is not adjustable in size; but the arms 31 and 32 are preferably made of telescoping sections so that they can be lengthened or shortened to accommodate automobiles of different wheelbase. The cross arms 33 and 34 can also be made of telescoping sections to accommodate automobiles of different tread, but the provision of this adjustment is less important than the length adjustment because most automobiles have a standard tread.

It will be apparent that a turntable of the type shown in FIGURE 3 with the load carried on platforms on arms which extend from a center hub portion, must necessarily have a small roller circle because there is no circumferential continuity to any of the turntable beyond the hub portion 25.

FIGURE 4 is an exploded view showing the telescoping arms 31 with their sections separated to illustrate the construction. Each of the arms 31 and 32 has an outer section 42 which is rigidly connected to the cross arms 33 and 34, respectively. Each arm 34 also has a section 44 which is rigidly connected with the hub portion 28 and these sections 44 telescope into the sections 42 and can be held in any adjusted position by pins 46 extending through an opening 48 in the outer section 46 and any one of a number of openings 50 spaced along the length of the inner section 44. Thus the turntable can be conveniently disassembled for shipment.

The turntable 20 has a base 54 which forms the bottom of the hub portion 28. This base 54 can be attached to the fioor, if desired, and must be attached to the floor if the load is to be unbalanced with respect to the axis of rotation by any substantial amount. For balanced loading or loading which is only slightly unbalanced and which leaves the center of gravity still within the confines of the base 54, it is not necessary to attach the base to the floor on which the turntable is supported.

The base 54 is increased in rigidity by ridges 56 which are preferably an integral part of the base. The base has a center post 22 supported in a bearing 58 attached rigidly to the base 54. The upper end of the post 22 can be fastened to the turntable 20 but this is not essential. In the construction illustrated, the post 22 is secured to the turntable 20 as an integral part of the turntable and extends into the bearing 58 to prevent lateral displacement of the turntable, but the post 22 and bearing 58 preferably carry none of the weight of the turntable.

Roller brackets 60 are attached to the ridges 56 in the construction illustrated. They may be attached to other parts of the base 54 but the advantage of using the ridges is to distribute the load over a greater area of the base 54.

On top of each of the brackets 60, there is a horn 64 secured to the bracket by bolts 66. An axle 68 extends through opposite sides of the horn 64 and supports a roller 70. There are two rollers 70- in the illustrated construction and a third roller 70 which is of the same construction as the rollers 70 except that it is wider and provided with a belt groove 72 by which the roller 70' is driven from a motor 74 secured to the base 54.

The motor 74 has a belt 76 which passes around pulleys to drive a speed reducer unit 76. The low-speed end of the speed reducer unit 76 is connected by a belt 78 to the roller 7 the belt 78 running in the groove 72 of the roller. The speed reducer unit 76 is attached to angle supports 80 by bolts extending through slots in the angles so that the speed reducer unit can be shifted to change the tension in the belts. The motor 74 is similarly connected to the base 54 by bolts extending through slots to permit further adjustment of the belt tension.

FIGURE shows the roller 70' on an enlarged scale. The axle 68 supports the inner part of a ball bearing and the outer part fits snugly in the roller 70. Rollers can be replaced by sliding the axle 68 out of the ball bearing and then removing the roller from the born 64. A new roller is placed in position in the horn and the axle 68 is pushed through the bearing of the new roller and secured in position by nuts 86 on the ends of the shaft.

The bracket 60 slopes so that the axle 68 which is substantially parallel to the top of the bracket 60, extends along a line 88 which is the axis of the conical or tapered circumferential surface of the roller 70'. The apex of this tapered surface is at a point 90 which is on the axis of rotation of the turntable, which axis is designated by the reference character -92. The point 90 is also located in the plane of a bottom surface 94 that contacts with the roller 70' to support the turntable. This construction provides minimum friction and wear.

When the turntable is originally assembled, shims can be placed between the horn 64 and the bracket 60, if necessary, in order to align the axis 88 with the point 90. It will be apparent, however, that by having the axle 68 removable, to replace rollers, without moving the born 64, makes the original alignment permanent and there is no necessity for realignment when worn rollers are changed. The rollers 70 and 70' are preferably made of plastic and with their brackets are rigid caster rollers.

Although this invention is particularly useful with turntables having small hubs and supporting arms which have little circumferential extent, circular platforms can also be placed on the turntable where the items to be displayed can be displayed more effectively on a continuous round turntable. The construction therefore has greater flexibility in the uses to which it can be put than in the case of turntables having large roller circles and which, therefore, require continuous circumferential extent of the turntable at distances close to the outer limits of the turntable.

What is claimed is:

1. In a turntable, a base, a rotatable top for carrying a load that is to be displayed, bearing means for preventing displacement of the top in a radial direction from its axis of rotation, rollers under the rotatable top and at angularly spaced locations around a circle for supporting the rotatable top, bracket means connecting each of the rollers with the base and supporting the rollers from the base, the bracket means having an axle for each of the rollers, each axle extending radially from the axis of rotation but at an acute angle thereto in a vertical plane, the bracket means being fixed to the base and the axle of each roller being removable from the bracket means for removal and replacement of the roller, a circular surface under the rotatable top for contact with said rollers as the top rotates, the diameter of the roller circle being less than one half the radius of the area swept by said rotatable top, and each of the rollers having a tapered face forming a portion of the area of a cone with its apex substantially on the axis of rotation of the top, and the axis of each axle being in line with the intersection of the axis of [rotation of the top and the plane of the circular surface that contacts with said rollers on which the top rotates.

2. The turntable described in claim 1 characterized by the bracket means comprising a separate horn for each roller with upstanding portions of each horn extending up on opposite sides of the roller and the axle extending through a bearing in the roller and being supported on opposite sides of the roller by said upstanding portions of the born.

3. The turntable described in claim 2 characterized by the base having a sloping surface on which each horn is supported, the sloping surface having the same slope as each axle and each horn supporting its axle at the same distance above the base on both sides of the roller.

4. The turntable described in claim 1 characterized by the rotating top having a hub portion of continuous circumferential extent and having arms extending beyond the hub portion at diametrically opposite locations on said hub portion, and load-carrying elements connected to the arms.

5. The turntable described in claim 4 characterized by the load-carrying elements being platforms located in position to support the wheels of an automobile, and

at least one of the arms being adjustable to accommodate the turntable to automobiles of different wheelbase.

6. The turntable described in claim 5 characterized by the arms having cross arms at their ends remote from the hub portion, the mid region of each cross arm being connected to one of the other arms, and the platforms being connected to opposite ends of the cross arms.

7. The turntable described in claim 6 characterized by the adjustable arm comprising two sections, one of which telescopes into the other, one of the sections being secured to the hub portion, and the other of the sections being secured to one of the cross arms.

8. The turntable described in claim 7 characterized by both of the arms which extend from the hub portion to the cross arms being adjustable in length so that the spacing of the cross arms from the supporting rollers can be adjusted to maintain the center of gravity of a supported load at a location within the roller circle.

9. The turntable described in claim 8 characterized by power driving means including a belt for transmitting motion to one of the rollers, and one of said rollers under the rotatable top having a circumferential groove therein into which the belt fits for driving said roller.

10. The turntable described in claim 9 characterized by the power driving means being located within the base and including an electric motor, a speed reducer driven by the electric motor, a pulley at the low-speed end of the speed reducer, the belt which drives said roller being located in position to run on the speed reducer pulley and on the roller having the belt groove for transmitting power from the speed reducer directly to said roller having the belt groove.

11. The turntable described in claim 1 characterized by the rollers being made of plastic and having antifriction bearings therein supported by the axles that are removable from said brackets for removal and replacement of the rollers.

References Cited UNITED STATES PATENTS 3/1962 OToole 104-44 2/1968 OToole 104-44 US. Cl. X.R.