CA2532429C - Vertically actuable roof cover for a spa - Google Patents

Abstract

An actuator and an assembly utilizing two or more actuators for vertically actuating a cover for a spa. In the lowered position the cover protects the spa and in the elevated position the cover acts as a roof over the spa. The actuator is either a rack and pinion assisted by a cable and pulley or a chain and a plurality of sprockets assisted by a cable and pulley which are connected to lift member which are generally shrouded by telescoping tubes to cover the actuators or to act as lift members themselves. The system can be further enhanced using a gas spring to assist in lifting the cover and reduce the load of the cover weight off the motor which is used to actuate the actuators.

Description

1 "VERTICALLY ACTUABLE ROOF COVER FOR A SPA"

2

3 FIELD OF THE INVENTION

4 Embodiments of the invention relate to spa covers and more particularly to spa covers which are moveable vertically between a position 6 directly atop the spa and a position elevated above the spa to act as a roof 7 structure during spa use.

It is known to cover hot tubs or spas to prevent contamination due 11 to environmental debris, such as leaves, pollens and the like, to prevent 12 excessive evaporation when the spa is not in use and to act as a safety measure 13 to prevent animals, small children and the like from falling into the water when 14 unsupervised.
Most conventional spa covers are fabric covered foam structures 16 which rest atop the spa when the spa is not in use and which are removed, 17 either by sliding off the tub or by folding at a middle and lifting to a position away 18 from the top of the tub, such by a support frame wherein the cover is suspended 19 vertically in the folded position adjacent a side of the tub. The fabric covers may be susceptible to chemical vapors, such as chlorine, are prone to tearing at 21 seams exposing the foam layers to the elements and to the steam and vapors 22 from the tub and are generally susceptible to normal wear and tear necessitating 23 multiple replacements during the life of the average spa.
24 It is known to provide fixed structures built around the hot tub to provide an element of protection for use during inclement weather or to prevent 1 excessive exposure to the sun. Most often the structure is independent of the 2 cover and remains in a fixed position around the tub, the roof portion being fixed 3 above the spa to permit use of the spa. While these structures may meet the 4 needs of the user by providing a rigid or semi rigid roof structure, they add additional expense by requiring a spa cover to be used as well.
6 Conventional spa covers are not designed to handle the weight of 7 a person or persons resting on the cover. As the spa covers are typically flat 8 however, individuals may be encourage to walk or otherwise provide undue 9 weight on the cover, such as when shoveling snow from a deck in which the spa is recessed, which results in damage not only to the cover but to the spa itself.
11 Others have attempted to provide domed rigid or semi-rigid cover 12 structures which, like the conventional cover, reside atop the spa when in use 13 and which are pivoted or slid laterally away from the spa when the spa is to be 14 used.
It is known to provide a vertically actuable cover to a swimming 16 pool or a spa. US Patent 3,566,420 to Peterson et al teaches hydraulic actuators 17 used to raise and lower a cover from a swimming pool and US Patent 6,718,566 18 to Wilson teaches a plurality of telescoping and threaded sections which are 19 used to raise and lower a cover over a spa.
There remains interest in the industry to find reliable, relatively 21 simple and inexpensive lift systems for raising and lowering roof structures over 22 spas, which can act to replace a conventional spa cover when in a lowered, spa 23 engaging position and which act as a roof when in the raised position.

2 A cover assembly for a structure, such as a spa, is vertically 3 actuated between a lowered position atop the spa to an elevated position above 4 the spa where the cover acts as a roof over the spa. The actuation of the cover is accomplished using actuation members which support the cover and which 6 employ unique lifting means, such as a rack and pinion system or a tension 7 member and rotatable guides, powered by a motor. The lifting means are 8 housed within telescoping tubular members which act to provide an aesthetic 9 covering for the lifting means and which may or may not form a part of the lifting means structure.
11 In a broad aspect therefore, a vertically-actuable cover assembly 12 for a structure comprises: a cover; and two or more actuation members for 13 supporting the cover, the two or more actuation members being actuable 14 between a lowered position atop the structure to an elevated position above the structure so as to act as a roof thereover, wherein the two or more actuation 16 members further comprise: a first lift structure mounted on a base fixed relative 17 to the structure; a second lift structure operatively connected to the first lift 18 structure and actuable to be raised and lowered for raising and lowering the 19 cover; a third upper lift structure operatively connected to the second lift structure; a rotatable guide supported adjacent a top end of the second lift 21 structure; a cable connected between the first structure and extending about the 22 rotatable guide for connection to a bottom end of the third lift structure;
and drive 23 means for driving the second lift structure to be lifted and lowered relative to the 24 first lift structure, wherein the rotatable guide is lifted and lowered by the second 1 lift structure so as to passively cause the cable to lift the upper lift structure 2 relative to the second lift structure.
3 The cover is supported on a plurality of actuation members, 4 typically one at each corner of the cover, having one or more motors. In a preferred embodiment, a plurality of electric motors are connected through a 6 single circuit so as to co-ordinate the actuation members to support and 7 vertically actuate the cover.
8 Preferably, stops are formed at top and bottom ends of the 9 telescoping tubular members to limit the upward travel of the telescoping members within each other to prevent the telescoping members from becoming 11 disconnected during elevation of the cover and to lift the intermediate member 12 with the upper tubular member.
13 In one embodiment, a rack and pinion lifting system is used 14 wherein the first lift structure is a pinion or worm gear mounted on a rotatable shaft, the second lift structure is a rack and the third lift structure is the upper 16 telescoping member which supports the cover. An electric motor drives the shaft 17 to rotate the worm gear which in turn engages the rack to be lifted and lowered 18 along with the structures connected thereto. A cable is connected between the 19 rack and an upper telescoping member, which forms part of the lifting structure and upon which the cover is supported, for assisting in raising and lowering 21 cover. The cable is guided by a pulley which is connected at a top end of the 22 rack. As the rack is moved so is the pulley at the top of the rack which causes 23 the cable to passively lift or lower the upper telescoping member to raise and 24 lower the cover. Limit switches act to stop the motor when the cover has reached the elevated or lowered position.

1 In an alternate embodiment, a tension cable and rotatable guide 2 system is used wherein the first lift structure is a housing mounted on a base for 3 telescopically housing a linearly extending member and the drive means is a 4 tension member which is driven about a plurality of rotatable guides which are positioned at the top and bottom of the housing and the top and bottom of the 6 second lift structure. One of the rotatable guides, preferably the guide at the 7 bottom of the housing, is driven by a motor. The third lift structure is a linearly 8 extending member telescopically housed in the second lift structure and to which 9 the cover is connected In a preferred embodiment the tension member is a chain or belt 11 and the rotatable guide are sprockets. Further a biasing means, such as a 12 hydraulic cylinder is provide to assist in lifting the second lift structure. The pulley 13 over which the cable extends is rotatably connected by a bracket adjacent the 14 top of the second lift structure and further to a hydraulic arm of the hydraulic cylinder. The cylinder arm is driven upwards as the chain lifts the second lift 16 structure thus reducing the load on the motor.

5 2 Figure 1 is a perspective view of a spa cover according to one 3 embodiment, shown in a raised position;
4 Figure 2 is a perspective view according to Fig. 1 shown in a lowered position;

6 Figure 3a is a longitudinal sectional side view of an actuation

7 mechanism for raising and lowering the spa cover, shown in the lowered

8 position;

9 Figure 3b is a longitudinal sectional side view according to Fig. 3a, shown in the raised position;
11 Figure 4a is a longitudinal sectional front view according to Fig. 3a, 12 in the lowered position;
13 Figure 4b is a longitudinal sectional front view according to Fig. 3a, 14 in the raised position;
Figure 5 is a detailed view of an embodiment of the actuation 16 mechanism, more particularly a worm gear and rack;
17 Figure 6 is a perspective view of the worm gear and rack of Fig. 5 18 shown in the lowered position and illustrating an alternate embodiment for 19 connection of the upper tubular member Figure 7 is a schematic sectional view of an embodiment of an 21 actuation mechanism having two telescoping tubular members, the upper tubular 22 member being connected to the rack;
23 Figure 8 is a schematic section view of an embodiment of the 24 invention according to Figs. 3a-4b having three telescoping tubular members, 1 the upper tubular member being connected passively to the rack through a cable 2 and pulley;
3 Figure 9 is a schematic of a circuit for independently operating of a 4 plurality of gear motors for rotationally powering worm gears;
Figure 10 is a schematic of a circuit for operating the plurality of 6 gear motors according to Fig. 9, in series;
7 Figure 11 is a schematic of another embodiment of the actuation 8 mechanism, more particularly a tension member and rotational guide system, 9 shown in a raised position, the telescoping tubular members having been removed for clarity;
11 Figure 12 is a schematic of the embodiment according to Fig. 11, in 12 a lowered position;
13 Figure 13 is a partial perspective view of the embodiment of Fig. 11 14 illustrating the telescoping arrangement of the lift structures in the actuation means; and 16 Figure 14 is an end view of the actuation means according to Fig.
17 11, the tension member removed for clarity.

2 Having reference to Figs. 1 and 2, a cover apparatus 1 for a 3 structure 2, such hot tub or spa, comprises a cover 3 supported on actuation 4 members 4, typically positioned at each corner of the spa 2. The actuation members 4 elevate the cover 3 from a lowered position, wherein the cover 3 6 rests atop or adjacent a top edge 5 of the spa 2, to a raised position, wherein the 7 cover 3 is supported over the spa 2 to act as a roof.
8 As shown in Figs. 3a,3b and 11, the actuation members 4 9 comprise a first lift structure 30 mounted on a base 13 fixed relative to the structure 2. A second lift structure 19 is operatively connected to the first lift 11 structure 30 and is actuable to be raised and lowered relative thereto for raising 12 and lowering the cover 3 supported thereon. A third upper lift structure 15 is 13 operatively connected to the second lift structure 19 and actuable to be raised 14 and lowered relative thereto. A rotatable guide, such as a pulley 23, is supported adjacent a top end of the second lift structure 19 and a first flexible tension 16 member such as a cable 16 is connected between the first structure 30 or the 17 base 13 and extending about the rotatable guide 23 for connection to a lower 18 end 21 of the third lift structure 15. Drive means 40, powered by a motor 31, is 19 provided for driving the second lift structure 19 to be lifted and lowered relative to the first lift structure 30 and in doing so lifts the rotatable guide 23 to passively 21 cause the cable 16 to lift the upper lift structure 15 relative to the second lift 22 structure 19.
23 As shown in Fig. 3a-6 and in one embodiment, the actuation 24 members 4 comprise a rack and pinion system 10 for raising and lowering the cover 3. Each actuation member 4 is housed within two or more telescoping 1 tubular members 11. The tubular members 11 may be, but are not limited to 2 being circular, rectangular or square in cross-section. Further, the tubular 3 members can form a part or all of the lift structures 30, 19 15 or shroud same.
4 Preferably, each actuation member 4 is housed within three telescoping tubular members 11, a lower tubular member 12 secured to the base 13, an 6 intermediate tubular member 14 and an upper tubular member 15 upon which 7 the cover 3 is supported. The rack and pinion system 10 is connected thereto for 8 active actuation of at least the second lift structure 19 and with it the intermediate 9 tubular member 14. The upper tubular member acts is the third lift structure and is connected thereto through cable 16 which is anchored, at a first end 17, to 11 the base 13 or to an upper end 18 (Fig. 6) of a rack 19 of the rack and pinion 12 system 10 for movement therewith and, at a second end 20, to a lower end 21 of 13 the upper tubular member 15. The cable 16 is guided at an upper end 22 of the 14 rack 19 by the pulley 23.
With reference to Figs. 7 and 8, preferably, a stop 24a is formed at 16 an upper end 25 of the lower tubular member 12 for engaging a stop 24b at a 17 lower end 26 of the intermediate tubular member 14 for retaining the 18 intermediate telescoping tubular member 14 in the lower telescoping tubular 19 member 12 and to prevent the intermediate tubular member 14 from being pulled aut of the lower tubular member 12, when the cover apparatus 1 is actuated to 21 the raised position. Similarly, a stop 24c is formed at an upper end 28 of the 22 intermediate member 14 for engaging a stop 24d at the lower end 21 of the 23 upper tubular member 15 for retaining the upper tubular member 15 within the 24 intermediate tubular member 14 during actuation to the elevated position.

1 Best seen in Figs. 6-8, the rack and pinion system 10 comprises a 2 worm gear 30 which is rotatably connected to the drive means 40, such as an 3 electric gear motor 31, by a rod 32. The worm gear 30 is rotated to raise and 4 lower the rack 19. For an actuation member 4 having two telescoping tubular members 11 (Fig. 7), rack 19 directly raises upper telescoping member 15. In the 6 case of an actuation member 4 having three telescoping tubular members 11 7 (Fig. 8), the rack 19 raises and lowers the upper telescoping member 15 via the 8 cable 16, the upper tubular member 15 raising and lowering the intermediate 9 tubular member 14 through engagement of the stops 24c,24d. As shown in Fig.
6, the cable 16 is connected at the second end 20 to a ring 33 which is used for 11 mounting the cable 16 inside the lower end 21 of the upper tubular member 15.
12 Preferably, each actuation member 4 is powered by an electric 13 gear motor 31. Most preferably, all of the gear motors 31 a, 31 b, 31 c, 31 d are 14 connected through a single circuit so that when the circuit is activated, all of the actuation members 4 are caused to move at the same time. Limit switches 40 16 are positioned on the rack and pinion system 10 to stop the gear motor 31 when 17 the cover 3 has reached the lowered or the raised position. As shown in Figs. 9 18 and 10, the gear motor limit switches 40 may be independent (Fig. 9) or in series 19 (Fig.10).
In an alternate embodiment as shown in Figs. 11-14, the first lift 21 structure 30 is an upwardly linearly extending lower housing which is connected 22 to the base 13. Best seen in Fig. 14, the second lift structure 19 is an 23 intermediate linearly extending member which is housed telescopically within the 24 lower housing 30 and the third lift structure 15 is an upper, linearly extending member which is housed telescopically within the intermediate member 19.

1 The drive means 40 comprises a durable, flexible tension member 2 41, such as a chain or belt and a plurality of rotational guides 42, such as 3 sprockets or pulleys. At least one of the rotational guides is connected to a motor 4 31, such as an electric gear motor for driving the tension member 41 thereabout.
The tension member 41 is arranged in a figure 8 having two 6 rotational guides 42 in one loop and two rotational guides 42 in the other loop.
7 Actuation causes the one loop to be displaced relative to the other loop, raising 8 one lift structure relative to the other.
9 As shown in Figs. 11 and 12, the tension member 41, such as a UNIFLEXT"" belt available from Jason Industrial Inc. of Fairfield NJ, 07004, USA, 11 is connected at either end 43, 44 to the intermediate member 19 and passes 12 about rotational guides 42 positioned at a top 45 and bottom 46 of the lower 13 housing 30 (a first loop) and at a top 47 and bottom 48 of the intermediate 14 member 19 (A second loop). As the motor 31 drives the at least one rotational guide 42, the intermediate member is raised (Fig. 11 ) and lowered (Fig. 12).
16 As in the previously described embodiment, the cable 16 is 17 connected to the lower end 21 of the upper member 15. The pulley 23 is 18 connected to the intermediate member 19 through a bracket 49. As the 19 intermediate member 19 is raised and lowered, the pulley 23 is also raised and lowered causing the length of the cable 16 between the pulley 23 and lower end 21 21 to shorten as the intermediate member 19 raises, causing cable 16 to 22 passively raise and lower the upper member 15.
23 In a preferred embodiment, best seen in Figs. 13 and 14, a slot 50 24 is formed along the length of the intermediate member 19 to accommodate connection of the cable 16 to the lower end 21 of the upper member 15 and to 1 permit movement of the upper member 15 relative to the intermediate member 2 19 for telescoping therein. At least an upper stop 51 is formed along the slot 50 3 to assist in preventing the upper member 15 from lifting out of the intermediate 4 member 19.
As shown in Fig. 14, the actuation members 4 in this embodiment 6 are housed within telescoping tubular members 11 so as to aesthetically cover 7 the lift structures 30, 19 and 15. An upper, lower and intermediate telescoping 8 member (not shown) are connected to one or more of the lift structures 30, 19, 9 15 so as to move with the lift structures 30, 19, 15 as each are raised and lowered. For example, the upper telescoping member may be connected to the 11 first lift structure 30 so that when the first lift structure 30 is lifted the upper 12 telescoping member is raised at the same time. More preferably, the upper 13 telescoping member is further connected to the intermediate telescoping 14 member so that the intermediate telescoping member is passively raised to cover the second lift structure 19 when the first and second lift structures 30, 19 16 are raised.
17 Optionally, as shown in Figs. 11-14 and in a preferred embodiment, 18 a biasing means 60, such as a hydraulic cylinder, is connected between the 19 lower housing 30 and the intermediate member 19 for assisting in lifting the intermediate member 19 to reduce load of the full weight of the cover 3 on the 21 motor 31. Preferably, an actuating arm 61 of the hydraulic cylinder 60, such as a 22 standard size 10 gas spring available from Industrial Gas Springs Ltd. of 23 Mitcham, Surrey, CR4 4HR, United Kingdom, is connected to the intermediate 24 member 19 through the bracket 49.

1 In a preferred embodiment, the cover 3 is a substantially rigid, 2 domed pyramidal-shaped cover manufactured of a foam core and having a fabric 3 covering such as is known in the industry to provide protection and insulation as 4 is also known with conventional spa covers. Further, the domed shape is particularly advantageous for spas which are enclosed in a deck structure to 6 prevent persons or animals from walking or lying on the cover 3 and to minimize 7 the amount of snow buildup on the cover 3 in snow-prone climates.

Claims (35)

THE EMBODIMENTS IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A vertically-actuable cover assembly for a structure comprising:
a cover; and two or more actuation members for supporting the cover, the two or more actuation members being actuable between a lowered position atop the structure to an elevated position above the structure so as to act as a roof thereover, wherein the two or more actuation members further comprise:
a first lift structure mounted on a base fixed relative to the structure;
a second lift structure operatively connected to the first lift structure and actuable to be raised and lowered relative thereto;
a third upper lift structure operatively connected to the second lift structure connected to the cover for raising and lowering the cover;
a rotatable guide supported adjacent a top end of the second lift structure;
a first tension member connected between the first structure and extending about the rotatable guide for connection to a bottom end of the third lift structure; and drive means for driving the second lift structure to be lifted and lowered relative to the first lift structure, wherein the rotatable guide is lifted and lowered by the second lift structure so as to passively cause the first tension member to lift the third upper lift structure relative to the second lift structure so as to lift the cover, wherein the actuation members are housed within a plurality of telescoping tubular members and connected thereto so as to raise and lower at least an upper and intermediate telescoping tubular member therewith.

2. The cover assembly of claim 1 wherein the first lift structure is a pinion driveably mounted on a rotatable member;
the second lift structure is a rack; and the drive means is connected to the rotatable member for rotating the pinion in engagement with the rack for raising and lowering the rack.

3. The cover assembly of claim 2 wherein the drive means for rotating the pinion in engagement with the rack is a motor.

4. The cover assembly of claims 2 or 3 wherein the pinion is a worm gear.

5. The cover assembly of any one of claims 2 to 4 wherein:
the rotatable guide is a pulley connected at a top end of the rack;
and the first tension member is a cable connected at a first end to the base and at a second end to the bottom of the third lift structure.

6. The cover assembly of any one of claims 1 to 5 wherein the third lift structure is the upper telescoping tubular member connected at a top end to the cover.

7. The cover assembly of any one of claims 2 to 6 further corn prising:
limit switches in the rack and pinion system for stopping the drive means when the actuation members reach the elevated position or the lowered position.

8. The cover assembly of claim 1 wherein:
the first lift structure is an upwardly linearly extending lower housing connected to the base;
the second lift structure is a linearly extending intermediate member housed telescopically within the first lift structure; and the drive means is a drivable second tension member extending in a figure-8, a first loop about rotatable guides positioned at a top and bottom of the first lift structure and a second loop about rotatable guides at a top and bottom of the second lift structure, at least one of the rotatable guides on the first lift structure being connected to a drive and wherein first and second ends of the second tension member are fixed to the second lift structure.

9. The cover assembly of claim 8 wherein the drive is a motor.

10. The cover assembly of claim 8 or 9 wherein the second tension member is a chain and the rotatable guides are sprockets.

11. The cover assembly of any one of claims 8 to 10 wherein the third lift structure is a linearly extending upper member telescopically housed within the second lift structure and connected at a top end to the cover.

12. The cover assembly of any one of claims 8 to 11 further comprising:
limit switches for stopping the drive when the actuation members reach the elevated position or the lowered position.

13. The cover assembly of any one of claims 8 to 12 further comprising:
biasing means connected to the second lift structure for assisting in lifting the cover.

14. The cover assembly of claim 13 wherein the biasing means is a hydraulic cylinder supported by the base.

15. The cover assembly of claim 14 wherein the rotatable guide is a pulley rotatably mounted adjacent the top end of the second lift structure and to a top end of a linearly actuable hydraulic arm of the hydraulic cylinder.

16. The cover assembly of any one of claims 8 to 15 wherein the actuation members are housed within a plurality of telescoping tubular members and connected thereto so as to raise and lower at least an upper and intermediate telescoping tubular member therewith.

17. The cover assembly of claim 16 wherein the plurality of telescoping tubular members are circular in cross-section.

18. The cover assembly of any one of claims 1 to 17 wherein the structure is a spa.

19. The cover assembly of any one of claims 1 to 18 further comprising four actuation members.

20. An actuator for a vertically actuable cover assembly for a structure comprising:
a first lift structure adapted to be mounted on a base fixed relative to the structure;
a second lift structure operatively connected to the first lift structure and actuable to be raised and lowered relative thereto;
a third upper lift structure operatively connected to the second lift structure adapted for connection to the cover for raising and lowering the cover;
a rotatable guide supported adjacent a top end of the second lift structure;
a first tension member connected between the first structure and extending about the rotatable guide for connection to a bottom end of the third lift structure; and drive means for driving the second lift structure to be lifted and lowered relative to the first lift structure, wherein the rotatable guide is lifted and lowered by the second lift structure so as to passively cause the first tension member to lift the third upper lift structure relative to the second lift structure adapted so as to lift the cover, wherein the actuator is housed within a plurality of telescoping tubular members and connected thereto so as to raise and lower at least an upper and intermediate telescoping tubular member therewith.

21. The actuator of claim 20 wherein the first lift structure is a pinion driveably mounted on a rotatable member; and the second lift structure is a rack; and the drive means is connected to the rotatable member for rotating the pinion in engagement with the rack for raising and lowering the rack.

22. The actuator of claim 21 wherein the pinion is a worm gear.

23. The actuator of claim 21 or 22 wherein:
the rotatable guide is a pulley connected at a top end of the rack;
and the first tension member is a cable connected at a first end to the base and at a second end to the bottom of the third lift structure.

24. The actuator of claim 23 wherein the third lift structure is the upper telescoping tubular member is adapted for connection at a top end to the cover.

25. The actuator of any one of claims 21 to 24 further comprising:
limit switches in the rack and pinion system for stopping the drive means when the actuator reaches an elevated position or a lowered position.

26. The actuator of claim 20 wherein:
the first lift structure is an upwardly linearly extending lower housing adapted for connection to the base;
the second lift structure is a linearly extending intermediate member housed telescopically within the first lift structure; and the drive means is a drivable second tension member extending in a figure-8, a first loop about rotatable guides positioned at a top and bottom of the first lift structure and a second loop about rotatable guides at a top and bottom of the second lift structure, at least one of the rotatable guides on the first lift structure being connected to a drive and wherein first and second ends of the second tension member are fixed to the second lift structure.

27. The actuator of claim 26 wherein the second tension member is a chain and the rotatable guides are sprockets.

28. The actuator of claim 26 or 27 wherein the actuation members are housed within a plurality of telescoping tubular members and connected thereto so as to raise and lower at least an upper and intermediate telescoping tubular member therewith.

29. The actuator of claim 28 wherein the third lift structure is a linearly extending upper member telescopically housed within the second lift structure and connected at a top end to the cover.

30. The actuator of any one of claims 26 to 29 further comprising:
limit switches for stopping the drive when the actuator reaches an elevated position or a lowered position.

31. The actuator of any one of claims 26 to 30 further comprising:
biasing means connected to the second lift structure adapted for assisting in lifting the cover.

32. The actuator of claim 31 wherein the biasing means is a hydraulic cylinder adapted to be supported by the base.

33. The actuator of claim 32 wherein the rotatable guide is a pulley rotatably mounted adjacent the top end of the second lift structure and to a top end of a linearly actuable hydraulic arm of the hydraulic cylinder.

34. The actuator of claim 23, 24, 28 or 29 wherein the plurality of telescoping tubular members are circular in cross-section.

35. The actuator of any one of claims 20 to 34 wherein the structure is a spa.