GB2446125A

GB2446125A - A mechanism for raising a tennis net

Info

Publication number: GB2446125A
Application number: GB0702148A
Authority: GB
Inventors: Brian Robert Duke
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-05
Filing date: 2007-02-05
Publication date: 2008-08-06
Also published as: GB0702148D0

Abstract

A mechanism for raising a tennis net comprises a hydraulic jack 2 contained within a support housing 1. A pulley 3 is mounted on a bearing anchored to the housing. A second pulley 5 is mounted on a bearing on the ram of the hydraulic jack. A chain or steel rope is anchored to the housing, passes over pulley 5, under pulley 3 and is attached to the net cord 10 which passes over roller 6. When actuated by the lever (8, fig 2) the hydraulic ram 12 draws the chain over the pulley, tensioning the net cord. The net may be released by opening control valve (7, fig 2) which withdraws the ram.

Description

Detailed description

Referring to figure 1. Main support housing I is preferably of suitably stout proportions and of suitable material. Hydraulic jack 2 is mounted in said housing I and is of sufficient stroke length.

Pulley 3 is mounted on a suitable bearing anchored to said housing I. Chain or steel rope 4 is anchored at one end to said housing I. Pulley 5 is mounted on a suitable bearing upon ram 12 of said hydraulic jack 2. Free roller 6 is anchored at the top end of said housing I over which net cord 10 passes. The said chain or rope 4 anchored at one end to said housing 1 passes over pulley 5 and under pulley 3 at the free end of which it is attached by suitable adaptor II to net cord 10 which passes over roller 6. Thus when the hydraulic jack ram 12 upon lever 8 actuation extends carrying said pulley 5 it drags the rope or chain around said pulley 3 to provide tension on said rope 4 which is anchored to said housing I at point 13 to tension said net cord 10.

Referring to figure 2. Hydraulic control valve knob 7 when closed allows said jack 2 to pull said net rope 10 and when opened allows said rope 10 to slacken and pay out as said jack 2 retracts. Said lack actuating lever 8 is moved in an arcuate motion to provide the pumping action to raise said jack ram 12 and so tighten said net cord 10.

Referring to figure 3 shows how this post design 9 may replace the regular post set into the court surface 14 as a means of precisely setting said rope 10 tension by a pumping action instead of rotating the usual rotary handle provided. I die

Tennis pre-set net support post

Background

Tennis top cord tension is important since it influences the trajectory of a ball as it strikes the top of the net so as to introduce a potentially uncontrolled factor into the game. It also further influences the net height since the net is usually supported between two stationary posts by the tension in the cord strung between the top of them. Net cord tension is frequently arrived at arbitrarily by the tightening mechanism situated at one or other net post which frequently results in under or over-tensioning and so is likely to result in poor ball control and post foundation damage. Typically net cord tension when in play is said to be around 400 lbf. tension.

Statement of invention

lo overcome this disadvantage one such means described herewith is where a jacking device is actuated by a hand lever that embodies a hydraulic jack which in this case together employs a direction reversing pulley or alternatively an inverted jack (not shown) but without a pulley to gain the appropriate direction of net cord tension. A ball valve within the jack is pre-set so as to limit the maximum force by an internal spring loaded pressure release valve so that precise net tension results regardless of excess actuation over a minimum number of actuations. This invention replaces a regular net post that uses a typical worm gear set.

Introduction to drawings

Figure I shows a diagrammatic internal view of the post.

Figure 2 shows a second diagrammatic but external view of the post.

Figure 3 shows an installed post on a tennis court. Cbims

Claims

I. A means of precisely limiting net cord tension irrespective of

actuating input handle over-stroking.
2. A means of pre-adjusting net tension level by a simple oil pressure release valve so therefore independent of user skill to achieve repeatable consistency.
3. A pulley arrangement that multiplies jack stroke length and facilitates upright jack mounting.
4. The possibility of inverting a jack of greater stroke to directly apply net cord tension without additional pulley.