GB2354164A

GB2354164A - Reinforced telescopic umbrella shaft

Info

Publication number: GB2354164A
Application number: GB9922051A
Authority: GB
Inventors: Max Wang
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-17
Filing date: 1999-09-17
Publication date: 2001-03-21
Also published as: GB9922051D0

Abstract

An umbrella shaft having telescopic inner 23 and outer 20 tube members, eg of multi-corner profile aluminium, is reinforced by a bar 30, eg of a carbon fibre material, fixed within the inner tube. The shaft includes a retaining mechanism to limit axial movement and prevent the tubes separating.

Description

1 2354164 TITLE: UMBRELLA SHAFT WITH REINFORCING BAR The invention relates

to an umbrella shaft, more particularly to a telescopic umbrella shaft with a reinforcing bar for enhancing the strength of the umbrella shaft.

It is known in the art to form inner and outer tube members of a telescopic umbrella shaft from iron to impart strength thereto. However, since iron is highly susceptible to corrosion, it has been proposed heretofore to make the umbrella shaft from aluminum to overcome this drawback.

Referring to Figures 1 and 2, a conventional telescopic umbrella shaft 10 made from aluminum is shown to include an inner tube member 12, an outer tube member 11 sleeved slidably and telescopically on the inner tube member 12, and a retainer unit consisting of an engaging hole 13 formed through the outer tube member 11 proximate to one end thereof, and a spring-loaded knob 14 mounted on an outer circumferential surface 15 of the inner tube member 12 proximate to one end thereof to limit relative axial movement and prevent axial disengagement therebetween when one of the inner and outer tube members 12, 11 is extended relative to the other one of the inner and outer tube members 12,11.

As illustrated, each of the inner and outer tube members 12, 11 has a multi-cornered cross-section so 2 as to strengthen the engagement therebetween. The inner tube member 12 is connected to a handle (not shown) for gripping by the user. It is noted that wind force is concentrated on the inner tube member 12 when the conventional umbrella shaft 10 is in an extended state.

Because the inner tube member 12 has a hollow construction and is formed from aluminum, which has relatively poor strength, the resistance of the umbrella shaft 10 is unsatisfactory.

It has been proposed heretofore to use a stronger material, such as iron, for the inner tube member 12, and a corrosion-resistant material, such as aluminum, for the outer tube member 11. Because two different materials are in use, the appearance of the umbrella shaft 10 is adversely affected, thereby reducing consumer appeal.

The main object of this invention is to provide a telescopic umbrella shaft with a reinforcing bar so as to eliminate the aforesaid disadvantages that are generally associated with the prior art.

Accordingly, the umbrella shaft of the present invention includes an inner tube member, an outer tube member sleeved slidably and telescopically on the inner tube member, a retainer unit provided on the inner and outer tube members to limit relative axial movement and prevent axial disengagement therebetween when one of the inner and outer tube members is extended 3 relative to the other one of the inner and outer tube members, and a reinforcing bar fittingly disposed in the inner tube member to reinforce the inner tube member.

Preferably, the inner and outer tube members are made of aluminum, and the reinforcing bar is formed from carbon fiber material.

Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiments of this invention, with reference to the accompanying drawings, in which:

Figure 1 is an exploded view of a conventional telescopic umbrella shaft; Figure 2 is a cross-sectional view of an inner tube member employed in the conventional umbrella shaft; Figure 3 is a fragmentary schematic partly sectional view of the preferred embodiment of a telescopic umbrella shaft of the present invention when in an extended position; and Figure 4 is a cross-sectional view of an inner tube member employed in the umbrella shaft of the preferred embodiment.

Referring to Figures 3 and 4, the umbrella shaft 20 of a preferred embodiment of the present invention is shown to include an inner tube member 23, an outer tube member 22, a retainer unit, and a reinforcing bar 4 30.

As illustrated, the outer tube member 22 is sleeved slidably and telescopically on the inner tube member 23. The retainer unit is provided on the inner and outer tube members 23, 22 to limit relative axial movement and prevent axial disengagement therebetween when one of the inner and outer tube members 23,22 is extended relative to the other one of the inner and outer tube members 23, 22. In the preferred embodiment, the retainer unit includes an engaging hole 222 formed radially through a lower end of the outer tube member 22, and a spring-loaded knob 232 mounted on an outer circumferential surface of the inner tube member 23 proximate to one end thereof such that when the outer tube member 22 is pulled axially and outwardly relative to the inner tube member 23, the knob 232 will engage the engaging hole 222 when registered therewith, thereby preventing axial disengagement between the tube members 23,22. A handle 21 is fixed to the other end of the inner tube member 23 for gripping purposes.

The reinforcing bar 30 is fittingly disposed in the inner tube member 23 to reinforce the inner tube member 23, and has a peripheral wall that abuts fittingly against an inner wall surface 231 of the inner tube member 23. Under such a condition, the rigidity of the inner tube member 23 can be increased to withstand a relatively strong wind.

The inner and outer tube members 23,22 are made of aluminum which is lightweight and resistant to corrosion. Therein forcing bar 30 is formed from c a rbon fiber material. Each of the inner and outer tube members 23, 22 and the reinforcing bar 30 has a multi-cornered cross-section to further enhance the strength of the umbrella shaft 20.

6

Claims

CLAIMS:

1. An umbrella shaft comprising:

an inner tube member; an outer tube member sleeved slidably and telescopically on the inner tube member; a retainer unit provided on the inner and outer tube members to limit relative axial movement and prevent axial disengagement therebetween when one of the inner and outer tube members is extended relative to the other one of the inner and outer tube members; and a reinforcing bar fittingly disposed in the inner tube member to reinforce the inner tube member.

2. The umbrella shaft as defined in Claim 1,wherein the inner and outer tube members are made of aluminum.

3. The umbrella shaft as defined in Claim 2,wherein the reinforcing bar is formed from carbon fiber material.

4. The umbrella shaft as defined in Claim 1,wherein each of the inner and outer tube members and the reinforcing bar has a multi-cornered cross-section.

5. The umbrella shaft as defined in Claim 1,wherein the reinforcing bar has a peripheral wall that abuts fittingly against an inner wall surface of the inner tube member.

6. The umbrella shaft substantially as described hereinbefore, with reference to and as illustrated in 7 Figures 3 to 4 of the accompanying drawings.