Locking Mechanism For Pedestal Seat

Abstract

Locking mechanism for a pedestal mounted seat is actuated by a spring biased handle which is mounted on the seat and which moves with the seat and carries an eccentric cam and guide member. In one position of adjustment, an outer tube carried by the seat is free to rotate about an inner tube carried by a floor mounted pedestal until the seat is in its aligned forward position at which point the guide member is moved into a slot in the inner tube. When the seat is in its forward position with the guide member in the slot, movement of the handle will rotate the eccentric cam into progressively greater contact with portions of the outer surface of the inner tube which are immediately adjacent the slot so as to prevent any wobbling taking place between the two tubes.

Description

BACKGROUND OF THE INVENTION

With the development of motor home and other multiuse vehicles a need has arisen for seats which can be rotated from a forward facing driving position to a position facing the interior of the vehicle. In order that the seat will be firmly anchored to the floor it is usually mounted on a pedestal comprising a pair of telescoped tubes which can be locked against rotation.

SUMMARY

It is among the objects of this invention to provide a rotatable vehicle seat support which can be locked in any position of rotation and easily and quickly released and moved to another position.

It is another object of this invention to provide a single lever actuated mechanism which will automatically lock the seat against rotation as it is rotated to its driving position and lock it against vibration.

These and other objects are accomplished by the improved mechanism of the present invention wherein a seat is provided with a tubular member projecting downwardly from its bottom into telescopic surrounding relation to a tubular member projecting upwardly from a floor mounted pedestal. A pair of brackets extend outwardly from the outer tube on opposite sides of an aperture. An elongated shaft having a handle portion on one end is mounted in the brackets and carries an eccentric cam member which is keyed to the shaft so that rotation of the handle will move the cam within the aperture into and out of engagement with a portion of the outer wall of the inner tube. When the cam engages the inner tube it forces the inner and outer tubes into tight engagement on the side thereof opposite the aperture so as to eliminate any looseness between the tubes which could cause rattles or vibrations during vehicle operation. A semi-annular ring portion on the cam is adapted to be moved into and out of a slot in the inner tube when the seat is aligned in its forward driving position. The ring cooperates with the sides of the slot to prevent rotary motion. A spring mounted on the shaft and in engagement with one of the brackets biases the ring towards the inner tube.

The operation of the mechanism can be briefly described as follows: assuming the seat is in its locked forward facing position the handle is turned to rotate the shaft which releases the cam from engagement with the inner tube and retracts the semi-annular ring from the slot. The handle can be released as soon as the seat is rotated a small distance away from the slot and the seat can be rotated to any position. The seat can be re-aligned in its forward position without touching the handle by simply rotating it until the spring biased semi-annular ring falls into the slot. Although the seat is locked against rotation in this position it is preferable to rotate the handle with some force to cause the eccentric cam to bind against the inner tube. This binding action prevents the tubes from rattling against each other or against the semi-annular ring and permits the tubes to be made with rather large manufacturing tolerances. It also overcomes the effects of wear on the tubes during use since the cam surface can be made to accommodate a large range of size variations between the two tubes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded, partially broken away perspective view of the improved locking mechanism;

FIG. 2 is a side sectional view showing the locking cam when the seat is not in its forward facing position; and

FIGS. 3 and 4 are side sectional views showing the locking cam in its initial and final contact positions relative to the tubular seat support members when the seat is in its forward facing position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a rotatable seat indicated generally at 10 includes a seat cushion 12 carried by a seat frame 14. An outer tubular member 16 welded to the seat frame 14 is telescoped over inner tubular member 18 which is welded to pedestal base member 20. A plurality of openings 22 formed in the base 20 may be used to receive a number of screws (not shown) which fasten the base 20 to the floor of a vehicle (not shown). Preferably, the fit between the outer and inner tubes 16,18 is a little loose to permit easy rotation of the seat 12 and to allow for manufacturing tolerances. Because of the loose fit the various portions of the unit 10 tend to rattle due to the vibrations of the vehicle (not shown) to which it is attached. To overcome the rattle, a centering and locking mechanism indicated generally at 23 has been provided.

The centering and locking mechanism 23 comprises a pair of brackets 24,26 which are welded to the outer tube 16. Circular openings 28 in the brackets function as bearings for a shaft 30 having a handle portion 32 integrally formed therefrom. In order to bias the shaft 30 in the direction indicated by the arrow a spring 36 is placed over the shaft and affixed at one end to a hole 38 in bracket 24 and affixed at its other end to an anchor pin 40 pressed into the shaft 30. An eccentric cam member indicated generally at 44 is affixed to the shaft 30 by a set screw 45. The eccentric cam member 44 has a gradually varying cam surface which includes a low cam surface portion 46 and a high cam surface portion 48. Extending outwardly from said cam surface between portions 46 and 48 is a semi-annular ring portion 50 having a leading edge 51 which is biased towards tubes 16,18 by spring 36. A slot 52 having a width slightly greater than the width of ring portion 50 is formed in inner tube 18. The slot 52 is positioned to receive ring portion 50 when the seat 12 is in its forward facing position so that the seat may be locked against rotation when in its driving position. An aperture 54 formed in the outer tube 16 is larger than the slot 52 so as to expose inner tube surfaces 56 on each side of slot 52 when the seat in in its driving position.

When the handle 32 is moved against the spring 36 to the upper dotted line position shown in FIG. 1 the cam 44 will be in the FIG. 2 position wherein the ring portion 50 is withdrawn from slot 52, thus permitting the seat 12 to be rotated to any desired position. Once the seat is rotated sufficiently far to prevent the ring portion 50 from reengaging slot 52 the handle 32 may be released and the edge 51 of ring portion 50 will merely ride on the surface of inner tube 18. As the seat is rotated back to its forward facing position the ring portion 50 will snap into slot 52 and prevent further rotation. When the ring portion 50 snaps into the slot 52 the handle 32 will assume the position shown in solid lines in FIG. 1 and the cam 44 will assume the FIG. 3 position. By applying manual pressure to force the handle 32 to the lower dotted line position shown in FIG. 1 the cam 44 will be rotated to cause the cam to press increasingly harder against the surfaces 56 of the inner tube 18 and cause the rear surfaces (not shown) of the tubes 16, 18 to bind together. The pressure increases since the cam is eccentric and surface 48 is further from the center of rotation of the cam than is surface 46. This firm pressure provided by the cam surface 48 prevents rattling taking place between the two tubes and between the ring portion 50 and the side edges of slot 52.

Claims

I claim as my invention:

1. In a rotatable seat for a motor vehicle having an outer tubular member attached to the seat frame and a telescoped inner tubular member attached to a base, the improvement comprising bracket means affixed to said outer tubular member, shaft means carried by said bracket means, cam means and detent means carried by said shaft, handle means on said shaft means for rotating said shaft, cam and detent means, a first aperture means formed in said inner tube and a second aperture means formed in said outer tube, said second aperture means being larger than said first aperture means and positioned relative to said first aperture means so that when the seat is in its driving position the first aperture means is positioned centrally of the second aperture means and aligned with said detent means whereby rotation of said handle means will cause said detent means to move into or out of said first aperture means and will cause said cam means to move into or out of evertightening engagement with portions of said inner tube located immediately adjacent said first means so as to force portions of said inner and outer tubes into binding contact with each other.

2. The device of claim 1 characterized in that said cam means and detent means are integral.

3. The device of claim 2 characterized in that said cam means includes a cam surface which is eccentric relative to said shaft and said detent means projects radially outwardly from said cam surface over the major portion of its extent.

4. The device of claim 1 characterized in that a spring is mounted on said shaft and connected to said shaft and to said bracket means for biasing said detent means towards said inner tube.