AU644744B2

AU644744B2 - Extendible pole

Info

Publication number: AU644744B2
Application number: AU18542/92A
Authority: AU
Inventors: Ronald Wilson
Original assignee: DAREX ENGINEERING Pty Ltd
Current assignee: DAREX ENGINEERING PTY Ltd
Priority date: 1991-08-15
Filing date: 1992-06-25
Publication date: 1993-12-16
Anticipated expiration: 2012-06-25
Also published as: AU1854292A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT tb S s~

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*5 Applicant(s): Invention Title: DAREX ENGINEERING PTY. LTD.

EXTENDIBLE POLE

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The following statement is a full description of this invention, including the best method of performing it knowni to me/us: EXTENDIBLE POLE This invention relates to an extendible pole and, in particular, but not exclusively, to an extendible light pole for supporting lighting. Whilst the pole could be used as a flag pole or for a variety of other purposes it will be primarily discussed with reference to the support of lighting for use with tennil courts.

Tennis court lighting generally comprises lights fixed to a pole at various locations around a tennis court. Generally the poles are fixed and the lighting is maintained at an elevated position at all times. Existing structures for supporting lights about tennis courts can be unsightly and the object of this invention is to provide a pole which overcomes this problem.

The invention provides an extendible pole, including: a base portion; an intermediate extension portion; an upper extension portion; a drive shaft arranged in the base portion; a nut member coupled to the intermediate extension portion and engaged with said drive shaft; a drive means for rotating said shaft about its longitudinal axis for driving the nut member and therefore the intermediate extension portion between a retracted and *o an extended position relative to the base portion; a guide member coupled to the intermediate extension portion; Sa cord member fixed at one end and extending over the guide member and having another end coupled to the upper extension portion; and wherein when the drive means rotates the drive shaft to 3 extend or retract the intermediate extension portion, the cord member extends the upper extension portion or allows the upper extension portion to retract relative to the intermediate extension portion.

Thus, since the pole of this invention has an extension ,ortion and a drive means for moving the extension portion relative to the base portion the pole can be retracted into the retracted position so that it is largely hidden and can be extended only when it is necessary to use the pole.

Thus, since the pole can be retracted when not in use it will not be unsightly when installed about a tennis court or the like.

Preferably the post also supports a sheave for guiding an electric cable, the electric cable passing through the base portion, through the intermediate extension portion over said sheave and through the top extension portion for supplying power to lighting connectable to the top extension portion.

9* Preferably the drive means includes a limit switch for automatically switching the motor on and off when the pole **too: is extended or retracted respectively and wherein the limit switch also switches on power to the electrical cable to S supply power to the lighting when the pole is in the 9 extended position and switches off the power when the pole is in the retracted position.

A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a cross-sectional view of a pole embodying the invention; 4 Figure 2 is a view along the line 11-11 of figure 1; Figure 3 is a view along the line III-III of figure 1; Figure 4 is an enlarged view in excploded form showing a nut member and an inner post using the preferred embodiment of the invention; Figure 5 is a view along the line V-V of figure 4; Figure 6 is a view of an inner post used in the preferred embodiment of the invention; and Figure 7 is a view along the line VII-VII of figure 6.

With reference to figure 1, a pole 10 is shown which will be described in conjunction with the support of lights for tennis courts or the like. However, the pole could be used for other purposes such as a flag pole or in any other environment where it is desired to suspend something above ground level.

The pole 10 comprises a base 12 which is :.:preferably tubular in construction of square cross-section and which is fixed in a waterproof housing 14. The wcerproof housing 14 houses a motor 16 and a limit switch 18.

A screw threaded shaft 20 is arranged within the base portion 12 and extends below the base portion 12. The portion of the shaft 20 below the base portion 12 has a pulley 22 for receiving a drive belt 24 from the motor 16.

The screw shaft 20 also has a sprocket 26 for receiving a chain drive belt 28 from the limit switch 18. The screw shaft 20 is mounted in a bearing (not shown) for rotation b.i. about its longitudinal axis.

An intermediate extension portion 30 also of tubular construction and square in cross-section is ;dimensioned and arranged to be telescopically receivable in the base portion 20. The intermediate extension portion carries a nut 32 which is engaged with the screw shaft The intermediate extension portion 30 also supports a post 34 which extends from the nut 32 into a top extension portion 40 which is also of tubular construction and square in cross-section and dimensioned to be telescopically receivable within the intermediate extension portion The post 34 supports a sprocket 42 and a sheave 44 (see figure A chain 46 runs from the bottom of base portion 12 to which it is secured, through the base portion 12, through the intermediate extension portion 30 over sprocket 6 42 and is connected to block 93 at the bottom of top extension portion Since, in the preferred embodiment of the invention, the pole is intended to support electrical lighting, an electrical cable 47 extends into the base 1A portion4a in the vicinity of the housing 14, through the base portion 20, through the intermediate extension portion over sheave 44 and up through top extension portion to the lighting supported on the top extension portion The power chord is connected to the limit switch 18 in the housing 14 for selectively supply power to the power chord to power the lighting supported on the top extension portion In order to extend the pole into the extended /b position shown in figure 1, the motor t is activated to **rotate screw shaft 20 about its longitudinal axis. This will drive the nut 32 upwardly along screw shaft 20 to thereby extend the intermediate portion 30 relative to the base portion 12. Simultaneously, the chain 46 is effectively pulled in the direction of arrow A in figure 1 in view of its connection to base portion 12 to thereby 00 0 pull the top section 40 upwards relative to the intermediate extension portion 30. When it is desired to retract the pole the motor 14 is driven in the opposite direction so that the nut 32 is screwed downwardly on shaft 20 to telescopically draw intermediate extension portion into the base 12. At the same time top extension portion begins to retract, under the influence of gravity into intermediate extension portion 30 with chain 46 rolling over sprocket 42 to enable the top extension portion 40 to retract into the intermediate portion 30 to thereby retract the pole. Thus, the pole in the retracted position is neatly stowed away and is of a height substantially equivalent to the height of the base portion 12.

During retraction of the pole the power cable 47 rolls over sheave 44 so that it is taken up as the top extension portion 40 retracts into the intermediate extension portion 7 As best shown in figures 2 and 4, the intermediate extension portion 30 includes a base plate which has a central hole 52 for accommodating the screw shaft 20. The base plate 50 also has shallow recesses 54 and 56 on its opposed faces. The recesses 54 and 56 as best seen in figures 2 and 3 are generally circular with a chord section cut from them. In the vicinity of the chord section is a slot 62 which passes through the plate 50 for accommodating the chain 46 and the power chord 47.

As is best shown in figure 4, nut 32 is provided with a central opening 33 for receiving the screw shaft and has an annular stepped portion 35 which is accommodated S. in the recess 54.

As is best shown in figure 6, post 34 has a o•00 I. •.generally annular flange 37 with a chord section cut from it to match the profile of the recess 56 and is slightly upwardly from the lower end of the post 34 to provide a stepped portion 39. The flange 37 is received in the reces 56 in plate 50 and bolts pass through openings 41 in the flange 37 through corresponding openings in the plate 50 and through openings 53 of the nut member 32 to thereby secure the post 34 and nut 32 to the intermediate extension S.portion °QeQ The flange 37 and recess 56 may have interconnecting spigots (not shown) to locate the flange 37 securely in the recess 56. The nut 32 and the recess 54 may also have interengaging spigots to secure the nut 31 in place. The stepped portion 35 on the nut 39 is slightly smaller than the recess 54 to allow slight sideways movement of the nut 39R if necessary in order to properly align it.

As is best seen in figure 5, the nut 32 is generally circular with a chord section cut from it so that its profile matches the profile of the flange 37 and the recesses 54 and 56. The generally cut-off portion of the nut 32 provides space for the chain 46 and the electrical Rcable 47 to pass the nut 32 and pass through the elongate 1 slot 62 in the base plate 50 to then extend through the 8 intermediate extension portion 30 between the generally square tubular wall of the intermediate extension portion and the post 34.

As is best shown in figure 2, the intermediate extension portion 30 is provided with spacer members which are welded about its outer periphery and which space and guide the intermediate extension portion 30 from the base portion 12.

The post 34 as shown in figure 6 includes a sprocket and sheave mount 70 which generally comprises a plate 72 which is asymmetrically arranged on the post 34 and the pair of upwardly extending plates 74 which have aligned holes 76.

~As is best seen in figure 3, the aligned holes 76 receive a pin 78 on which the sprocket 42 is mounted via bushings 82. The pin 78 also mounts the sheave 44 via bushings 92. The sprocket 42 receives and guides chain 46 which passes up through intermediate extension portion then over the sprocket 42 and is fixed at the bottom 93 (see figure i) of top extension portion 40. The electric cable 47 similarly passes up through intermediate extension portion 30, into top extension portion 40, over the sheave 44 then back up through the top extension portion 40 to the lighting (not shown) supported on the top extension portion As is best seen in figure 3, the top extension portion 40 includes spacers 95 for spacing the top extension portion 40 from the intermediate extension portion 30 and for guiding the top extension portion within the intermediate extension portion As also best seen in figure 3, the top extension portion 40 may include a guide 96 for guiding the chain 46 onto sprocket 42 and maintaining the chain 46 on the sprocket 42. Rollers (not shown) may also be provided for use in conjunction with sheave 44 to prevent electrical cable 47 from lifting off the sheave 44.

The plate 50 may be provided with its drain holes so that any water which collects within the pole can 9 drain through the pole. Similarly, bearings arranged for supporting the screw shaft 20 can also be provided with holes so that water drains through the pole and does not sit in or on any of the components in the pole.

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

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Claims

1. An extendible pole, including: a base portion; an intermediate extension portion; an upper extension portion; a drive shaft arranged in the base portion; a nut member coupled to the intermediate extension portion and engaged with said drive shaft; a drive means for rotating said shaft about its longitudinal axis for driving the nut member and therefore the intermediate extension portion between a retracted and an extended position relative to the base portion; a guide member coupled to the intermediate extension portion; a cord member fixed at one end and extending over the guide member and having another end coupled to the upper extension portion; and wherein when the drive means rotates the drive shaft to extend or retract the intermediate extension portion, the cord member extends the upper extension portion or allows the upper extension portion to retract relative to the intermediate extension portion.

2. The pole according to claim 1 whea:ein, the intermediate I" extension portion is telescopically movable relative to the base portion and the top extension portion is telescopically movable relative to the intermediate •extension portion so that the top extension portion can be retracted into the intermediate extension portion and both 0* the intermediate extension portion and the top extension portion can be retracted into the base portion. 11

3. The pole according to any one of the preceding claims wherein, the drive means comprises a motor for rotating the screw shaft such that the engagement between said screw shaft and the nut causes said nut to be driven along the screw shaft to move the intermediate extension portion between the retracted position and the extended position.

4. The pole according to any one of the preceding claims wherein, the cord member comprises a chain member extending from the base portion through the intermediate extension portion to said upper extension portion for connection to the upper extension portion and the guide means comprises a sprocket.

The pole according to claim 4 wherein, said intermediate extension portion includes a support post therein for supporting the sprocket over which said chain is guided.

6. The pole according to any one of the preceding claims wherein, the post also supports a sheave for guiding an electric cable, the electric cable passing through the base portion, through the intermediate extension portion over said sheave and through the upper extension portion for supplying power to lighting connectable to the top extension portion.

The pole according to any one of the preceding claims wherein the drive means includes a limit switch for automatically switching the motor on and off when the pole :is extended or retracted respectively and wherein the limit switch also switches on power to the electrical cable to supply power to the lighting when the pole is in the extended position and switches off the power when the pole 12 is in the retracted position.

8. A pole substantially as hereinbefore described with reference to the accompanying drawings. Dated this 5th day of October 1993 DAREX ENGINEERING PTY. LTD. By Its Patent Attorneys: GRIFFITH HACK CO. Fellows Institute of Patent Attorneys of Australia. ABSTRACT A pole is disclosed which has a base an intermediate extension portion (30) and a top extension portion A screw threaded shaft (20) is arranged within the base portion (12) and is in screw threaded engagement with the intermediate extension portion A chain (46) runs from the bottom of the base portion (12) and is connected 10 to the top extension portion The shaft (20) is i" driven so that the intermediate extension portion (30) is moved relative to the base portion (20) to extend that portion and movement of the intermediate portion causes the top portion 40 to be extended relative to the 15 intermediate portion by virtue of the chain (46) which rides over a sprocket (42) and is connected between the base portion (12) and the top extension portion C