Abstract:
A sliding lock mechanism for a rotary seat assembly includes an operating lever which rotates together with a seat of the assembly, thereby eliminating any operating lever projecting from the back of the seat.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a sliding lock mechanism for a rotary seat assembly used in an automobile and the like, particularly a lock mechansim having an operating lever projecting only forward of the seat in the assembly. 
     A conventional seat e.g. for an automobile is intended to be slidable and rotatable. A slidable and rotatable seat assembly as shown in FIG. 1 is comprised by a pair of rails (1)A and (1)B mounted on the floor (10) of the automobile, a pair of leg portions (2)A and (2)B mounted to the lower surface of a lower base of a seat (5) and slidably fitted to the rails (1)A and (1)B, thereby providing the lower base (2) in a slidable relationship with the floor (10), in addition, an annular ring rail (3) affixed to the upper surface of the lower base (2) and provided with a rail groove (3)A in which the periphery of a leg portion (4)A mounted to the lower surface of an upper base (4) is fitted so as to install the upper base (4) rotatably on the lower base (2), and the seat (5) being affixed to the upper surface of the upper base (4) through a frame (5)A. 
     In such a construction, a conventional sliding lock mechanism would be, as shown in FIGS. 1 and 2, comprised by support shafts (6)A and (6)B depending from the lower surface of the lower base (2), operating levers (7)A and (7)B respectively rotatably mounted to the support shafts (6)A and (6)B, a connecting lever (8) pivotally affixed to the connected ends of the operating levers (7)A and (7)B, and a lock pin (9) connected to the end of the connecting lever (8), whereby the lock pin (9) is inserted into one of a plurality of holes (10)A formed in series in the inner wall of rail (1)B and into a hole (10)B formed in the inner wall of the corresponding leg portion (2)B so as to lock the leg portions (2)A and (2)B in place with respect to the rails (1)A and (1)B, wherein when the seat (5) is faced forward, the operating lever (7)A is used to insert and withdraw the lock pin (9) into and from the hole (10)A of the rail (1)B and the hole (10)B of the leg portion (2)B, while when the seat is faced backward, the operating lever (7)B is used to insert and withdraw the lock pin (9) into and from the holes (10)A and (10)B. 
     In the construction, however, the operating lever (7)A or (7)B projecting from the back of the seat (5) as shown in FIG. 3 may injure a leg of a passenger on the rear seat and cause other troubles. 
     Accordingly, a primary object of the present invention is to provide a rotary seat assembly to overcome the drawbacks of the prior construction mentioned above. 
     Another object of the present invention is to provide a sliding lock mechanism to rotate an operating lever together with the rotation of the seat so as to position the operating lever always forward of the seat. 
     SUMMARY OF THE INVENTION 
     The present invention, in accordance with one embodiment thereof, is incorporated in a rotary seat assembly comprising rails mounted on the floor of an automobile, a lower base having a lower surface to which leg portions are mounted in a slidable fitting relation with the rails, an upper base rotatably mounted on the lower base, and a seat mounted on the upper base, and comprises an operating means provided adjacent to the upper base and connected to a lock means to lock the sliding movement of the leg portions relative to the rails, wherein in the condition where the leg portions are locked by the lock means, the operating means and the lock means are rotatably connected to each other on the rotation centerline of the upper base. Accordingly, it is possible to use regardless of the direction of the seat an operating lever positioned forward of the seat to lock the sliding movement of the seat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross sectional view as referenced from the forward side of a conventional rotary seat assembly, 
     FIG. 2 is a partial plan view showing leg portions and operating levers, 
     FIG. 3 is a side elevational view of the conventional rotary seat assembly, 
     FIG. 4 is a cross sectional view as referenced from the forward side of a rotary seat assembly according to the present invention, 
     FIG. 5 is a partially cut-away perspective view of a lock mechanism incorporating the present invention, 
     FIG. 6 is a plan view of an operating means and a lock means according to the present invention, 
     FIG. 7 is a partially cut-away side elevational view of a leg portion and a rail according to the present invention, 
     FIG. 8 is a partial plan view of an operating means and a lock means in another embodiment according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 4 shown in one embodiment of the present invention, a pair of rails (11)A and (11)B are mounted on the floor (20) of an automobile, and a pair of leg portions (12)A and (12)B are mounted to the lower surface of a lower base (12) in slidable fitting relation with the rails (11)A and (11)B, whereby the lower base (12) is slidably mounted on the floor. The lower base is provided with an opening (12)C at the central portion thereof and formed with an annular ring rail (13) on the upper surface thereof, the ring rail being provided with a rail groove (13)A into which the periphery of the leg portion (14)A affixed to the lower surface of an upper base is fitted, whereby the upper base (14) is rotatably installed relative to the lower base (12). The frame (15)A of the seat (15) is affixed to the upper surface of the upper base (14). 
     In a sliding lock mechanism for the construction as mentioned above, a support shaft (16) depends from the lower surface of the upper base (14), and an operating lever (17) is rotatably connected to the lower end of the support shaft (16) for the center P of rotation and has the forward end portion thereof projected forward from the seat (15). Rotatably connected to the other end (17)A of the operating lever (17) is a connecting lever (18) which is at the other end thereof formed with a claw member (18)A. The claw member (18)A is engaged with a pivotal lever (19)A at the outside thereof which is pivotally connected to a bracket (12)D extending from the leg portion (12)A. A lock pin (19) is connected to the pivotal lever (19)A. 
     In the construction mentioned above, the operating lever (17) for an operating means rotates together with the seat (15) while the connecting lever (18), the pivotal lever (19)A and the lock pin (19) which form conjointly a lock means do not rotate together with the seat (15). The connecting point (17)A of the connecting lever (18), that is, the connecting point between the operating means and the lock means coincides with the rotation center of the seat (15) or the rotation center P&#39; of the upper base (14) when the sliding movement of the seat (15) is locked. A plurality of holes (20)A for adjusting the position of the seat are juxtaposed on the inner wall of one rail (11)A while a pair of holes (20)B are provided in the corresponding leg portion (12)A, wherein the leg portions (12)A and (12)B can be slided relative to the rails (11)A and (11)B to have the holes (20)A and (20)B mate with one of the combinations of two holes (20)A so as to insert the bicuspid end of the lock pin(19) into the holes (20)A and (20)B whereby the leg portion (12)A can be locked at a predetermined position relative to the rail (11)A. In this condition, the pivotal lever (19)A is biased by a spring (19)C mounted around the pivotal shaft (19)B in a direction of the insertion of the lock pin (19) into the holes (20)A and (20)B. When the operating lever (17) is rotated against the force of the spring (19)C to the position as shown by dotted lines in FIG. 6, the lock pin (19) can be stripped from the holes (20)A and (20)B so that the leg portion (12)A is slidable relative to the rail (11)A. When the seat (15) is rotated 180 degrees, in other words, the upper base (14) is rotated 180 degrees relative to the lower base (12) with the leg portion (12)A being in a locked condition by the lock pin (19), in other words, with the sliding movement of the seat (15) being locked, the operating means or the operating lever (17) is also rotated 180 degrees in the direction as shown by the arrow. The lock means comprising the connecting lever (18), the pivotal lever (19)A and the lock pin (19) is unchanged in position because the rotation center P&#39; is coincident with the connecting point (17)A between the connecting lever (18) on the lock means side and the operating lever (17) when the seat (15) is placed in the slide lock condition. 
     The present invention should not limited to the embodiment set forth above. For instance, the rotation center P of the operating lever (17) may be located opposite to the forward end of the operating lever (17) with respect to the rotation center P&#39; of the seat as shown in FIG. 8. In addition, the connecting point (17)A may be movable in position through an elongated hole (17)B of the operating lever (17).