Patent Publication Number: US-6032305-A

Title: Spa cover lifter

Description:
This application is a continuation-in-part of application Ser. No. 08/948,017, filed Oct. 10, 1997, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a lifting mechanism for removing and replacing the cover of a spa. The use of spas has become widespread, and most spas are equipped with covers which when closed prevents debris, rain and the like from contaminating the tub water. The cover further serves to retain heat within the tub. As a consequence, spa covers tend to be relatively heavy and difficult to remove and replace. 
     Lifting devices have been developed to aid in the removal and replacement of these relatively heavy spa covers. These devices can be operated with varying amounts of difficulty. 
     Some problems exist with past lifting mechanism designs. A unit with one lifting arm can produce excessive wear on the edge of the spa and the bottom of the spa cover when the cover is slid and pushed to the &#34;off&#34; position. 
     With only one lifting arm the spa cover tends to become angularity offset when the operator pulls or pushes on one side only. This can produce additional wear on the spa and spa cover. Some units require a chain or link to limit travel. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to improve the apparatus for removing and replacing relatively heavy spa covers. 
     A still further object of the present invention is to provide a lifting apparatus for a spa cover that provides sufficient mechanical advantage so that it can be easily operated by one person to remove and to replace a relatively heavy spa cover. 
     Another object of the present invention is to provide a lifting apparatus for a spa cover that provides minimal contact between the cover and the spa surfaces during removal and replacement operations. 
     An additional object of the present invention is to stow the cover at the low point travel of the near lift bar thus eliminating the need for excess travel chains or cables. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing objects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings wherein: 
     FIG. (1) is one quarter elevated view of the spa cover on the spa in the &#34;on&#34; position. 
     FIG. (2) is a one quarter elevated view of the spa cover in the &#34;intransit&#34; position. 
     FIG. (3) is a one quarter elevated view of the spa cover in the &#34;off&#34; position. 
     FIG. (4) is a side view showing the spa cover in the &#34;folded on&#34; position. Also shown is the chain drive lift mechanism. 
     FIG. (5) is a detail view of the gearbox, sprocket, and direct current motor. 
     FIG. (6) shows the socket shaft with sprocket and mounting provisions, a crank with hexagon drive bit, which may be inserted into the socket is also shown. 
     FIG. (7) shows a portable alternating current electric motor with gear reduction, switch, wiring, and hexagon bit which may be inserted to power the socket shaft. 
     FIG. (8) shows a portable air motor with gear reduction, valves and hexagon bit which may be inserted to power the socket shaft. 
     FIG. (9) shows a portable hydraulic motor with gear reduction, valves, and hexagon bit which may be inserted to power the socket shaft. 
     FIG. (10) shows a portable direct current electric motor with gear reduction, batteries, wiring, switch, and hexagon bit which may be inserted to power the socket shaft. 
     FIG. (11) shows a surface mounted gear box with direct current motor drive attached to the right side plate. A sprocket is attached to the output shaft and a chain is used to connect with the lift bar sprocket. A forward/off/reverse switch with wiring connects the battery to the motor. 
     
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INDEX OF REFERENCE NUMBERS                                                
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22.              Spa                                                      
23.                 Lift Bar, Center                                      
24.                 Lift Bar, Near                                        
25.                 Side Plate, Left                                      
26.                 Flap, Cover Joining                                   
27.                 Flap, Center Bar Retaining                            
28.                 Flap, End Bar Retaining                               
29.                 Zipper ®                                          
30.                 Stitching                                             
31.                 1/2 Spa Cover, Far                                    
32.                 1/2 Spa Cover, Near                                   
33.                 Screw Mounting                                        
34.                 Spring                                                
35.                 Spring Anchor                                         
36.                 Chain                                                 
37.                 Pivot Bolt, End Bar                                   
38.                 Pivot Bolt, Center Bar                                
39.                 Side Plate, Right                                     
42.                 Crank                                                 
43.                 Hexagon Drive                                         
44.                 Battery                                               
45.               Switch                                                  
46.               Wiring                                                  
47.               Gear Box                                                
48.               Shaft, Gear Box                                         
49.               Motor                                                   
50.               Bolt                                                    
59.               Bearing                                                 
60.               Mount                                                   
61.               Socket                                                  
62.               Shaft, Sprocket Mount                                   
64.               Weld                                                    
65.               Collar                                                  
66.               Set Screw                                               
67.               Sprocket, Socket Drive                                  
69.               Spacer                                                  
70.               Hole                                                    
71.               Sprocket, Main Shaft                                    
72.               Roller Chain                                            
75.               Side Plate Extension                                    
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     DESCRIPTION OF THE INVENTION 
     FIG. (1) shows the lifting apparatus installed on a spa and spa cover. The cover is shown in the &#34;on&#34; position. The left side plate (25) is attached to the spa using bolts or screws. The right side plate is attached to the right side in a similar manner. The near lift bar is installed at the end of the spa using pivot bolts (37). 
     The center lift bar (23) is installed using pivot bolts (38). The center and near lift bars are attached to the near half of the cover (32) using flaps (27) and (28) and zippers® (29). 
     Counter balance springs, FIG. (1) reference (34), are installed on both sides of the spa. The dead end of the springs (34) are connected to the side plates (25) and (39). The live ends are attached to the spacer chains (36), which in turn are connected to the lower ends of the center lift bar (23). In use, spring tension is not required in the initial removal movement of the cover, thus the lift bar (23) can travel a measured distance until all slack is taken out of the chains (36) and the springs (34) are beginning to stretch. 
     Using the flaps (27),(28) and zippers (29) shown in FIG. 4 the lift bars may be attached to the spa cover (32) without having to drill holes through the cover to install u-bolts or other mechanical fasteners. 
     FIG. (6) shows a crank (42) which can be inserted to drive the socket (61) and shaft (62) with sprocket (67) and roller chain (72) connecting the sprocket shaft with the large sprocket (71) on the near lift bar (24). Rotating the crank clockwise will move the spa cover to the &#34;on&#34; position. Rotating the crank counterclockwise will move the spa cover to the &#34;off&#34; position. 
     Alternate means of powering the socket shaft are provided as shown in FIGS. (7) through (10), which include an alternating current powered drill, an air powered drill, a hydraulic powered drill and a direct current battery powered drill. 
     FIG. (5) shows an alternate means for turning the sprocket (67). A motor (49) connected to a power source through wiring (46) is used to drive a gear box (47) which turns a shaft (48) connected to the sprocket (67). The turning of shaft (48) causes the sprocket (67) to move the chain drive (72) and crank (42) to move the cover. The gear box (47) is mounted on one of the plates (39) by a mounting bolt (50).