GB2386579A

GB2386579A - Telescopic tube with an eccentric lock

Info

Publication number: GB2386579A
Application number: GB0206850A
Authority: GB
Inventors: Chia Kun Cheng
Original assignee: Shang Gu Enterprise Co Ltd
Current assignee: Shang Gu Enterprise Co Ltd
Priority date: 2002-03-22
Filing date: 2002-03-22
Publication date: 2003-09-24
Anticipated expiration: 2022-03-22
Also published as: GB2386579B; GB0206850D0

Abstract

The locking mechanism is operated by turning a main seat 10 which, via a polygonal rod 17 and secondary seat 30, rotates an eccentric strap 35 into a locking position. A rubber ring 37 is mounded around the strap 35 (having a displaced axis), which is mounted around a portion of the secondary seat 30. The rod 17 extends between the main 10 and secondary 30 seats. When in the locked position the strap 35 tightly presses against an inner wall of an outer tube. The jammed strap 35 prevents axial movements of the telescopic tubes. Outer 20 and inner 40 tube supports are mounted around the main 10 and secondary 30 seats. Preferably the tubes 24, 41 have an elliptic cross-section. The tubes can be used in handles.

Description

LOCKING MECHANISM FOR TELESCOPIC TUBE

BACKGROUND OF THE INVENTION

5 The present invention relates to a locking mechanism for telescopic tube, and more particularly to a locking mechanismfor telescopic tube consistingofinnerandouter tubes having an elliptic cross section.

10 Telescopic tubes are frequentlyamployed in many products for different purposes, such as being used as handles of various types of tools, in order to provide such handles with variable lengths. When an inner tube of the telescopic tube has been set to a desired position relative 15 to en outer tube thereof to reach a selected overall length of the handle or other product, the inner tube has to be locked to that desired position. To do this, there has been tried to connect a cylinder-shaped fixed rubber seat to an end of the inner tube that is to be inserted into 20 the outer tube. The fixed rubber seat is provided with an eccentric positioning hole. A link interconnects the positioning hole on the fixed rubber seat and a through hole on a movable rubber seat, so that the positioning heoleandthethroughholeareat the same eccentricposition 25 on the fixed and the movable seats. When the inner tube

is fitted into the outer tube, the movable rubber seat is located outside the inner tube but inside the outer tube. When the inner tube and the outer tube are rotated relative to each other, an outer surface of the eccentric 5 movable rubber seat would be forced against an inner wall of the outer tube and thereby lock the inner tube to a fixed position relative to the outer tube. And, when the inner and the outer tubes are rotated relative to each otherina reverse direction, the eccentriamovable rubber 10 seat is loosened from the inner wall of the outer tube end the inner tube is allowed to move up and down relative to the outer tube and be adjusted to another desired axial position. 15 The above-described locking manner of employing an eccentric rubber seat does not applicable to tubes having a non-circular cross section, such as an elliptic cross section that might be adopted to match a configuration of a tool or to achieve some special function. Moreover, 20 the above-described locking manner is not convenient for operation. It is therefore triedbytheinventorto develop animproved licking mechanism for telescopic tube that includes inner 25 end outer tubes having an elliptic cross section end could

be conveniently operated.

SUMMARY OF THE INVENTION

5 A primary object of the present invention is to provide a locking mechanism for telescopic tube, particularly for telescopic tube including elliptic inner and outer tubes.

To achieve the above and other objects, the locking 10 mechanism for telescopic tube according to the present invention mainly includes a main seat on and around which anoutertubesupportismountedforanoutertubetofixedly connect to an outer periphery of the support, a secondary seat on and around which an inner tube support is mounted 15 for en inner tube to fixedly connect to an outer periphery of the support. A polygonal rod extends through the main seat and the secondary seat, so that rotation of the main seat would cause the polygonal rod and the secondary seat to rotate along with the main seat at the same time. The 20 secondary seatincludes an eccentric portion around which an eccentric strap is firmly mounted to rotate along with the secondary seat, and besides a rubber ring surrounds the eccentric strap. Bypulling or pushing the inner tube to a desired height relative to the outer tube and then 25 turning the main seat for the polygonal rod to rotate the

secondary seat, the eccentric strap is caused to rotate into a position to tightly press against an inner wall surface of the outer tube to lock the inner tube to the desired height. With the locking mechanism, the inner 5 and the outer tube of the telescopic tube may have an elliptic cross section.

BRIEF DESCRIPTION OF THE DRAWINGS

10 Thestructureandthetechnicalmeansadoptedbythepresent invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the

accompanying drawings, wherein Fig. 1 is an exploded perspective of a locking mechanism for telescopic tube according to the present invention; Fig.2 isaverticalsectionalviewofthelockingmechanism 20 for telescopic tube of Fig. 1 in an assembled state and in a position allowing the inner tube to be axially moved relative to the outer tube; Fig. 3 is a cross sectional view of the locking mechanism 25 for telescopic tube of Fig. 1 in an assembled state and

in a position allowing the inner tube to be axially moved relative to the outer tube; Fig. 4 is a cross sectional view of the locking mechanism 5 for telescopic tube of Fig. 1 in an assembled state and in a position locking the inner tube to the outer tube; and Fig. 5isaverticalsectionalviewofthelockingmechanism 10 for telescopic tube of Fig. 1 in an assembled state and in a position locking the inner tube to the outer tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

15 Please refer to Figs. 1, 2 and 3. The present invention relates to a locking mechanism for locking an inner tube to a desired position relative to an outer tube of a telescopic tube. The mechanism mainly includes a main seat 10, an outer tube support 20, a secondary seat 30, 20 an eccentric strap 35, and an inner tube support 40.

The main seat 10 is a multistage column including a predetermined number of vertically stacked cylinders of different diameters. In the illustrated drawings, the 25 main seat 10 includes three stages. One of the cylinders

that has the largest diameter is located at a bottom of the main seat lOand the one that has the smallest diameter is located at a top of the main seat 10, as viewed from the illustrated drawings. The largest cylinder is 5 provided at a top near an outer periphery thereof with a recess 11 in which a spring 12 is disposed to support aball13 thereon. The smallest cylinder is axially split into two parts with a groove 14, and provided at a top with racially outward end downward extended hook portions 10 15. The main seat lo defines an axially extended internal through hole 16 that has a polygonal cross section. A rod 17 having a polygonal cross section corresponding to that of the internal hole 16 is extended into the hole 16 from a bottom of the main seat 10 to upward project 15 from the top of the smallest cylinder.

The outer tube support 20 is a hollow member having a diametrically expanded lower portion 21 having a round cross section and a diametrically reduced upper portion 20 23 having an elliptic cross section. The outer tube support 20 defines a stepped round inner hole 25 and is therefore adapted to mount around the main seat 10 with the roundlower portion 21 seated on the top of the largest cylinder of the main seat 10 and a top of the elliptic 25 upper portion 23 located slightly below the hook portions

15 of the main seat 10. The round lower portion 21 is provided at a bottom surface with a plurality of recesses 22 corresponding to the recess 11 on the main seat 10 in order to engage with the ball 13 received in the recess 5 11. An outer tube 24 having an elliptic cross section corresponding to that of the upper portion 23 is mounted around and fixedly connected to the upper portion 23. A C-ring 26 is positioned on a top of the elliptic upper portion 23 to connect the outer tube support 20 to the-,.; 10 mainseatlOwhileallowsthemainseatlOtorotaterelative to the outer tube support 20.

The secondary seat 30definesanaxially extendedinternal through hole31. The through hole 31 has apolygonalcross 15 section corresponding to that of the through hole 16 in the main seat 10 and therefore allows the polygonal rod 17 to upward extend through the secondary seat 30 via the throughhole31. Thesecondaryseat30isalsoamultistage column andincludes a diametrically reduced end eccentric 20 middle portion 32. A smallest upper portion of the secondary seat 30 is also axially split into two parts with a groove 33. A top of the smallest upper portion also forms radially outward and downward extended hook portions 34.

At) The eccentric strap 35 is made of a Teflonimaterial so that it is highly wear-resistant. The eccentric strap 35, which is surrounded on the top of a rubber ring 37, defines a round central hole 36 adapted to engage around 5 the eccentric middle portion 32 of the secondary seat 30.

Whereby, when the secondary seat 30 and accordingly the eccentric middle portion 32 thereof are rotated, the eccentric strap 35 mounted around the eccentric middle portion32 rotates along with the eccentric middle portion 10 32.

Theinnertubesupport40isalsoamultistagecolumnadapted to mount around the secondary seat 30 above the eccentric strap 35, such that a top of the inner tube support 40 15 is located below and abuts on the hook portions 34 of the secondary seat 30 for the inner tube support40 to fixedly connect to the secondary seat30. A diametricallyreduced elliptic upper portion 401 of the inner tube support 40 is adapted to fixedly support an elliptic inner tube 41 20 therearound. The outer tube support 20 end theinner tube support 40 are so dimensioned that the outer tube 24 and the inner tube 41 mounted around the tube supports 20 and 40, respectively, are spaced from each other by a suitable clearance that allows the inner tube 41 to be moved up 25 and down relative to the outer tube 24, as shown in Figs.

2 and 3.

To adjust an axial height of the inner tube 41 relative to the outer tube 24 when the locking mechanism of the 5 present inventionis in a position allowing theinner tube 41 to axially move relative to the outer tube 24, first pull or push the inner tube 41 relative to the outer tube 24 to a desired height, as shown in Fig. 2. Then, rotate themainseatlOby90degrees. Atthispoint,thepolygonali-.

10 rod 17 in the main seat 10 rotates along with the main seat 10 and drives the secondary seat 30 fitly located around the rod 17 to rotate by 90 degrees, too. When the eccentric strap 35 mounted around the eccentric middle portion 32 of the secondary seat 30 rotates along with 15 thesecondaryseat30byapredeterminedangletoaposition that causes the eccentric strap35totightlypressagainst an inner wall surface of the outer tube 24 and could not move any further, as shown in Fig. 4, it causes the inner tube 41 mounted around the inner tube support 40 that is 20 connected to the secondary seat 30 to be locked to the desired height relative to the outer tube 24. With the above arrangements, the locking mechanism for telescopic tube according to the present invention is applicable to inner and outer tubes 41 and 24, respectively, that has 25 a non-circular cross section, such as an elliptic cross

section. Withtheabove-mentionedspecialarrangements,thelocking mechanism for telescopic tube according to the present 5 invention has at least the following advantages: 1. The locking mechanism of the present invention may be employed on a telescopic tube having elliptic inner and outer tubes. In the present invention, when the lo elliptic inner tube 41 is pulled or pushes to a desired height relative to the outer tube 24, turning the main seat 10 would rotate the rectangular rod 17 and the secondary seat 30 at the same time and thereby drives the eccentric strap 35 mounted around the secondary 15 seat30torotateintoapositiontotightlypressagainst the inner wallsurfaceof the outer tube24, and thereby locks the inner tube 41 to the desired height relative to the outer tube 24.

20 2. The locking mechanism of the present invention could be conveniently operated to lock the elliptic inner tube 41 to a desired height relative to the elliptic outer tube 24 simply by rotating the main seat 10 by 90 degrees for the eccentric strap 35 to tightly press 25 against the inner wall surface of the outer tube 24.

Claims

What is claimed is:

1. A locking mechanism for telescopic tube, comprising a main seat, an outer tube support, a polygonal rod, 5 a secondaryseat,an eccentric strap, and an inner tube support; said outer tube support being adapted to mount on and around said main seat and to support an outer tube 10 therearound; said polygonal rod teeing upward extended from a bottom of said main seat into said secondary seat, such that turning of said main seat could cause said polygonal 15 rod to rotate along with said main seat and to drive said secondary seat to rotate at the same time; said eccentric strep being mounted around an eccentric portion of said secondary seat to rotate along with 20 said secondary seat; said rubber ringheingmountedaroundan eccentric strep; and 25 said inner tube support being mounted around said

secondary seat above said eccentric strap and supporting an inner tube therearound; whereby when said polygonal rod is rotated by said main 5 seat to cause said secondary seat to rotate at the same time, said eccentric strap mounted around said eccentric portion of said secondary seat is rotated to a position to tightly press against an inner wall surface of said outer tube and could not be moved any 10 further, preventing said secondary seat, and accordingly said inner tube support end saidinner tube from axially moving relative to said outer tube and causing saidinner tube tobelockedat a height relative to said outer tube.

2. A locking mechanism for telescopic tube as claimed in claim 1, wherein said outer tube support includes an upper portion having en elliptic cross sectionand said outer tube is a hollow tube having an elliptic cross 20 section corresponding to that of said upper portion of said outer tube support for fitly mounting therearound; and wherein said inner tube support includes an upper portion having an elliptic cross section and said inner tube is a hollow tube having 25 an elliptic cross section corresponding to that ofeaid

upper portion of said inner tube support for fitly mounting therearound.

3. A locking mechanism for telescopic tube as claimed in 5 claim 1, wherein said main seat is a multistage column including a predetermined number of vertically slacked cylinders of different diameters, one ofeaid cylinders that has the largest diameter being located at a bottom of said main seat and being provided at a top near an --

10 outer periphery thereof with a first recess in which a spring is disposed to support a ball thereon; and wherein said outer tube support is provided at a bottom surface with a plurality of second recesses corresponding to said first recess on said main seat 15 and adapted to separately engage with said ball supported on said spring in said first recess.

4. A locking mechanism as claimed in claim 3, wherein the secondary seat defines an axially-extended, internal through-hole having a polygonal cross-section corresponding to that of the polygonal rod for the polygonal rod to extend therethrough, \/

one end of the secondary seat being axially split into two parts with a vertical groove, and radially-outward and extended hook portions being provided at one end of the rod-receiving seat for holding the inner tube support to, and around, the secondary seat; and wherein the eccentric strap is provided with a round central hole adapted to engage 5 with the eccentric portion of the secondary seat for the eccentric strap to rotate along with the secondary seat.

4. A locking mechanism for telescopic tube as claimed in claim 2, wherein said main seat is a multistage column 20 including a predetermined number of vertically slacked cylinders of different diameters, one of said cylinders that has the largest diameter being located at a bottom of said main seat and being provided at a top near an outer periphery thereof with a first recess in which 25 a spring is disposed to support a ball thereon; and

wherein said outer tube support is provided at a bottom surface with a plurality of second recesses corresponding to said first recess on said main seat and adapted to separately engage with said ball 5 supported on said spring in said first recess.

5. A locking mechanism for telescopic tube as claimed in claims, wherein said secondary seat defines an axially extendedinternalthrough hole haying a polygonal cross 10 section corresponding to that of said polygonal rod for said polygonal rod to extend therethrough, a top of said secondary seat being axially split into two parts with a vertical groove, and radially outward and downward extended hook portions being provided on said 15 top of said rod-receiving seat for holding said inner tube support to and around said secondary seat; and wherein said eccentric strap is provided with a round centralholeadaptedtofitlyengagewitheaideccentric portion ofeaid secondary seat for said eccentric strap 20 to rotate along with said secondary seat.

6. A locking mechanism for telescopic tube as claimed in claim 4, wherein said secondary seat defines an axially extendedinternalthrough hole haying a polygonal cross 25 section corresponding to that of said polygonal rod

for said polygonal rod to extend therethrough, a top of said secondary seat being axially split into two parts with a vertical groove, and radially outward and downward extended hook portions teeing provided on said 5 -top of said rod-receiving seat for holding said inner tube support to and around said secondary seat; and wherein said eccentric strep is provided with a central round hole adapted to fitly engage with said eccentric portion of said secondary seat for said eccentric strep 10 to rotate along with said secondary seat.

Amendinents to the claims have been filed as follows : 1. A locking mechanism for a telescopic tube having an elliptical cross-section, the mechanism comprising a main seat, an outer tube support, a polygonal rod, a 5 secondary seat, an eccentric strap, and an inner tube support; the outer tube support being adapted to mount on and around the main seat and to support an outer tube therearound; 10 the polygonal rod extending from the main seat to the secondary seat, such that turning of the main seat causes the polygonal rod to rotate along with the main seat and to drive the secondary seat to rotate at the same time; the eccentric strap being mounted around an eccentric portion of the secondary seat to 15 rotate along with the secondary seat; a rubber ring being mounted around the eccentric strap; and .... the inner tube support being mounted around the secondary seat above the eccentric 20 strap and supporting an inner tube therearound; whereby, when the polygonal rod is rotated by the main seat to cause the secondary seat to rotate at the same time, the eccentric strap mounted around the eccentric portion of the secondary seat is rotated to a position to press tightly against an inner wall surface 25 of the outer tube whereby it cannot be moved any further, thereby preventing the -\

secondary seat, and accordingly the inner tube support and the inner tube from axially moving relative to the outer tube and causing the inner tube to be locked at a height relative to the outer tube.

2. A locking mechanism as claimed in claim 1, wherein the outer tube support includes an upper portion having an elliptic cross-section, and the outer tube is a hollow tube having an elliptic cross-section corresponding to that of the upper portion of the outer tube support for mounting therearound; and wherein the inner tube support includes an upper portion having an elliptic cross-section, and the inner tube is a 10 hollow tube having a elliptic cross-section corresponding to that of the upper portion of the inner tube support for mounting therearound.

3. A locking mechanism as claimed in claim 1 or claim 2, wherein the main seat is a mtlti-stage column including a predetermined number of vertically-stacked .. ,", 15 cylinders of different diameters, the cylinder having the largest diameter being located at one end of the main seat and being provided at the other end of the main seat, near , " ", an outer periphery thereof, with a first recess in which a spring is disposed to support a ball thereon; and wherein the outer tube support is provided at one end surface with a ... plurality of second recesses corresponding to the first recess on the main seat and 20 adapted separately to engage with the ball supported on the spring in the first recess.