GB2340164A

GB2340164A - A tensioning device for a vehicle side curtain

Info

Publication number: GB2340164A
Application number: GB9816740A
Authority: GB
Inventors: Philip Peter Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-08-03
Filing date: 1998-08-03
Publication date: 2000-02-16
Also published as: GB9816740D0

Description

2340164 rift Improvements to Vehicle Side Curtains

Technical field

This invention relates to a tensioning device used in conjunction with a vehicle side curtain for applying a constant pre-determined load or force to each of the vertical reinforcing straps in order to secure the curtain in its closed position.

Background

Curtain-sided vehicle bodies are well known and have been in use for more than 30 years, principally to give fast and total access to a vehicle body for a variety of freight distribution applications. An integral part of the bodywork is the side curtain, not only to weather proof the load compartment of the vehicle but also to increase the structural integrity of the bodywork and in some cases to act as a primary or secondary load retaining membrane. The side curtain is generally made from flexible PVC coated material with a plurality of vertical reinforcements usually of webbing material either fixed to the inside of the curtain or free running within a sleeve arrangement. At the lower end of each vertical reinforcement and to the outside of the curtain is fitted a tension buckle complete with a lower strap and hook assembly for attachment to the lower rail or side rave of tho veicle chassis. By pulling the free end of the lower strap and closing the buckle, the operator applies tension to each of the vertical reinforcements in turn thus securing the curtai4',in 2 its closed position The curtain is also tensioned longitudinally but by different means. The present design of the tension buckle and its fitment to the lower outside face of the curtain has 3 distinct disadvantages:

1. Applied Tension: The present tension buckle and lower strap assembly relies totally upon the discretion of the operator to apply sufficient pre-tension by pulling the free end of the strap and closing the latch of the buckle. It can therefore be stated with probability that some of the buckle assemblies are too slack and may become easily detached from the lower rail or side rave of the vehicle.

2. Personal Injury/Damage: With the tension buckle assemblies fitted to the outside of the curtain at a height within reach of the operator, the risk of injury to pedestrians and cyclists in urban and city areas is acute, especially if the lower strap and hook becomes detached from the lower rail or side rave of the vehicle due to incorrect tensioning - an occurrence which is not uncommon. Also, side mounted tension buckles are vulnerable to being 'snagged' and in some cases completely torn away often resulting in extensive damage to the curtain.

3. Application of Corporate Livery: With the tension buckles fitted at their normal working height to the outside of the curtain, the available space for graphics or sign writing is effectively reduced by an average of 20%. In situations where the whole surface area of the curtain has been used for livery, then the tension buckles not only impair the visual effect of the finished product but may also create extensive damage.

3 DESCRIMON According to the present invention, there is provided a tensioning device which has means to apply a constant pre-determined force or load to the vertical reinforcements of a vehicle side curtain and may be mounted in such a manner as to be unobtrusive to the outside face of the vehicle side curtain.

Specific embodiments of the invention will now be described by way of examples with reference to the accompanying drawings in which:- Fizure-I Shows in perspective the device prior to placement onto the lower rail or side rave flange item H.

Figure 2 Shows the device located onto the side rave or lower rail flange - Point 'A' is the typical pre-tension position for a curtain of normal height - Point Al is the pre-tensions position for a curtain up to 25m/m over height - Point V is the overcentre position prior to final locking. The linear travel from A to B = 50m/m and from Al to B = 25m/m.

Figgre-I TI-ds shows the device at Point V (over-centre) moving to Point 'C' (fully closed and locked). As the lever moves beyond the over-centre position, the device will 'snap shut' and lock by itself, resulting in a relaxation in linear movement of approximately 10%. KtRure 4 Shows the device fully closed and locked. The total linear travel from 4 Point Wto Point 'C' = 45m/m. The total linear travel of 45m/m is abitary. The travel may be extended by repositioning the two support shafts, Figure 8 items 2 & 4.

FiViry 5 Shows in perspective the device in the fully closed and locked position and demonstrates the profile when made from a plastic material.

Figure 6 Illustrates the tension geometry in the fully closed position FiZure 7 Illustrates the tension geometry in the open position.

Figure 8 Shows the plan and side elevation of the device.

FiZyre 9 Shows the end elevation of the device.

Figyrre 10 Illustrates the constant force spring and housing assembly.

This invention provides for a device that is capable of applying a tension load or force to each of the vertical reinforcements straps on a vehicle side curtain where the applied load or force to each strap is constant and where all the adjustment Le. slack material is 'taken-up' within the mechanical arrangement of the device. The ability to mount the device on the lower rail or side rave of the vehicle chassis and away from the outside face of the curtain is desirable.

Referring to the drawing Figure 8, the device is shown in a pressed and punched format and can be manufactured from a range of materials including stainless steel, mild steel and aluminium. The choice of material used is governed by the fact that the device is situated beneath the chassis in a position which attracts all the worst of the elements. Stainless steel represents the obvious choice with its additional strength, corrosion resistant qualities and proven reliability on side curtain applications. Another material which would satisfy the criteria for this device and once again has proven acceptability for use on side curtains is thermo-setting plastic. Figure 5 shows a typical profile for the assembly with the basic principles of operation remaining identical to the pressed version.

The principle feature and main novelty claim for the device is the constant force spring assembly Figure 10 item 15 which takes-up all the adjustment and applies a constant load to the curtain without the need for any adjustment by the operator. The load or force to be applied will be determined with reference to experimentation. The spring is of stainless steel and has an average fatigue life of 15,000 cycles. The spring item 15 is pre-coiled and assembled into the housing item 14 with the outer fixed end located within a slot in the wall of the housing item J. The housing is fitted to the side plate Figure 8 item 10 and held by 3 split shouldered nipples within the moulding - the housing cannot be removed accidentally.

The tension shaft Figure 8 item 6 has a slot running along its centre line for almost the whole of its length, to allow for:

6 a) The webbing strap Figure 6 item D to be secured. b) To engage the free end of the spring Figure 9 item K. This shaft passes through both side plates Figure 8 item 10 and is secured in position by 2 circlips Figure 9 item 12. The webbing strap Figure 6 item D should ideally be a continuation of the vertical PVC coated webbing that is attached to the back of the curtain - this webbing has a 'sticky' surface coating (PVC) giving a high frictional resistance, ideal to prevent 'slippage' when the device is locked. The tail end of the webbing strap Figure 6 item D is secured to the tension shaft Figure 6 item 6 by 2 roll pins Figure 9 item 13 before being wound onto the shaft (3 turns) as shown in Figure 7, however there is no tension on the shaft at this point - tension only occurs when the lever Figure 8 item 11 is forced from position A to position C - effectively 'winding-up' the constant force spring and transmitting that load into the curtain.

From the tension shaft, the webbing passes over a support pin and sleeve Figure 7 items 7 & 8 - the sleeve is a loose fit allowing the webbing to run freely before passing around the strap support shafts Figure 8 items 2 & 4. These support shafts, unlike item 8, are fixed in position by 2 roll pins Figure 8 item 3 - this is intended to increase the frictional resistance of the PVC coated webbing in the fully locked position as shown in Figure 6. A high resistance to 'slippage' of the webbing will prevent the spring from continually moving due to road vibration. Also, the resistance at Point 'D' together with the spring tension, prevents the device from disengagement with the lip of the side rave or lower rail. Also by secondary means the device is further prevented from detachment from the lip of the side rave or lower rail by the addition of a torsion spring, fitted to and actuated by the closing of 7 the tension lever (not shown). 'Ihe torsion spring bears against the lip of the side rave or lower rail.

The body of the device is a fabrication combining the 2 side plates Figure 8 item 10 and the flange mount item 9, welded as shown to form a rigid assembly upon which to mount all other components. The throat height of the flange mount item 9 may be varied to suit different thickness of side rave or lower rail flange. Although shown as a weldment, alternative methods of manufacture may be used and the method of construction could differ accordingly - however, the basic design principles and profile will remain similar to that shown.

The tension lever Figure 8 item 11 is attached to the side plates item 10 of the body assembly by 2 semi-tubular rivits item S. Contained within the lever pressing is a torsion spring item 1 - when the lever is at position V (fully dosed), the spring latches into the side plate item 10 to prevent self-opening. To release, thumb pressure forward will disengage the spring from the slot in the side plate and the lever can be fully opened.

Also, within the lever pressing item 11 are 2 holes shown at 'E' - when the lever is closed these holes align with similar holes in the side plates through which a cable can be fitted. This cable can be locked at each end of the chassis to form a security device preventing the curtain being opened when the vehicle is unattended.

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Claims

1. According to the present invention, there is provided a tensioning device which has means to apply a constant pre-determined force or load to the vertical reinforcements of a vehicle side curtain and may be mounted in such a manner as to be unobtrusive to the outside face of the vehicle side curtain.

2. A tensioning device as claimed in Claim 1, wherein a spring is provided within the mechanism to control the amount of load applied to the vertical reinforcements in a vehicle side curtain. Ideally this spring will be of a type known as a constant force spring.

3. A tensioning device as claimed in Claim 1 or Claim 2 wherein all the 'slack' or adjustment within the side curtain is automatically 'taken-up' by the spring.

4. A tensioning device as Claimed in any preceding Claim wherein the device is mounted onto the lip of the lower rail or side rave of vehicle and separately from the outside face of the side curtain.

5. A tensioning device as Claimed in any proceeding Claim wherein the device is attached to the PVC coated webbing reinforcement of the curtain and uses the texture of the webbing reinforcement to increase the frictional resistance and help prevent movement within the device when in the locked position.

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6. A tensioning device as Claimed in any preceding Claim wherein the body of the device is prevented from disconnection from the side rave or lower rail of the vehicle by means of a torsion spring fitted to and actuated by closing the tension lever. The spring making contact with the side rave or lower rail of the vehicle (not shown).

7. A tensioning device as Claimed in any preceding Claim wherein the device has an over-centre tension lever mechanism which is lockable in its closed state by means of a torsion spring arrangement, thus preventing the device from opening accidentally.

8. A tensioning device as Claimed in any preceding Claim wherein the device is further prevented from opening unintentionally by the addition of a wire cable passing through holes in the tension lever and body assembly.

9. A tensioning device substantially as described herein with reference to Figures I10 inclusive of the accompanying drawings.

9. A tensioning device substantially as described herein with reference to Figures 110 inclusive of the accompanying drawings.

Amendments to the claims have been filed as follows I - According to the present invention, there is provided a tensioning device which has means to apply a constant pre-determined force or load to each of the vertical reinforcing straps on a vehicle side curtain and may be mounted in such a manner as to be unobtrusiv.- to the outside face of the vehicle side curtain.

2. A tensioning device as claimed in Claim 1, wherein a constant force spring made from a flat stainless steel strip is provided within the mechanism to control the amount of load applied to each of the vertical reinforcing straps on a vehicle side curtain. This constant force spring is of a type used in a clock mechanism where a constant torque output is required.

3. A tensioning device as claimed in Claim I or Claim 2 wherein all the 'stack' or adjustment within each of the reinforcing straps on a vehicle side curtain is automatically 'taken-up' by the spring.

4. A tensioning device as Claimed in any preceding Claim wherein each device is mounted onto the lip of the lower rail or side rave of the vehicle and separately from the outside face of the side curtain. Each tensioning device is operated manually and individually one from another.

5. A tensioning device as Claimed in any proceeding Claim wherein the device is attached to each of the PVC coated webbing reinforcing straps on a vehicle side curtain and uses the 'sticky' texture of the webbing reinforcement to increase frictional resistance and help prevent movement within the device when in the locked position.

6. A tensioning device as Claimed in any preceding Claim wherein the body of the device is prevented from disconnection from the side rave or lower rail of the vehicle by means of a torsion spring fitted to and actuated by dosing the tension lever. The spring making contact with the side rave or lower rail of the vehicle (not shown).