Patent Description:
Vehicle glazing panels such as vehicle windscreens (windshields) are typically bonded in supporting frames by adhesive bonding material such as polyurethane, applied in a continuous bead about the periphery of the glazing panel and frame.

Wire cutting techniques have been previously proposed and used to effect glazing panel removal (for replacement or otherwise). Exemplary techniques are disclosed in, for example, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>, <CIT>, <CIT> and <CIT>. In particular <CIT> and <CIT> disclose techniques in which, during cutting, the wire can be operated in certain circumstances to slip or slide with respect to the bonding material in order to saw or cut through the bonding material. This has proved advantageous.

<CIT> discloses a technique which improves upon the earlier techniques by utilizing slip cutting in a more controlled and consistent manner. The technique can be used with cutting wire or a cutting line not of metal such as a synthetic fibre cutting line.

In the technique of <CIT>, a loop of the cutting line is formed around the periphery of the entire windscreen in a set up phase and the cutting line is attached at opposed ends to each of respective winders spools of the cutting device. In the cut out procedure when winding in on one of the winder spools the other is configured to allow the cutting line to be drawn off the respective spool. In other words the line is attached to both spools during the cutting procedure and slip is achieved by permitting winding off from one of the spools as the line is wound on to the other. As a result there can be constant slip cutting throughout substantially the entire process (certainly for the majority of the cut out process).

Respective winder mechanisms associated with each spool have ratchets which are toggled between a 'forward ratchet permitted' position and a 'reverse ratchet permitted' position (and a neutral ratchet off position) to enable winding onto or off a respective winder spool during the cut out procedure. In the ratchet operating positions rotation is permitted in one direction only. The ratchet as shown schematically for <FIG> comprises a spring loaded pawl which engages in teeth in a ratchet collar mounted on the drive shaft of the spool drive mechanism. The pawl is provided with an angled slip surface and the pawl can be lifted back against the spring so as to be rotated about its axis to reverse the position of the slip surface through <NUM> degrees. These alternative positions are the 'forward ratchet permitted' position and a 'reverse ratchet permitted' positions referred to earlier. In the configuration of <FIG> rotation is permitted in one direction only and in the other configuration (<FIG>) the reverse direction only. It is possible to hold the ratchet in the neutral position as shown in <FIG> in which rotation is permitted in either direction.

When the ratchet is operating in either the configuration of <FIG> each time, in the direction of permitted rotation, the pawl lifts over the teeth as rotation is effected effectively slightly compressing the spring each time. This results in greater torque being required to effect rotation than would otherwise be the case for rotation without the ratchet.

<CIT> relates to a mechanism for enabling one-way unwinding.

An improved technique and apparatus has now been devised.

According to the invention, there is provided a winder unit for winding cutting line, the winder unit comprising a rotatable spindle shaft for winding; a ratchet device being mounted to the spindle shaft by means of a one-way rotational bearing or clutch; and mounting means for mounting the winder unit to a glazing panel.

It is preferred that the ratchet device comprises a component mounted to rotate in unison with the one-way rotational bearing or clutch.

Preferably the ratchet device comprises a ratchet collar mounted to the one-way rotational bearing or clutch.

In one embodiment the one-way rotational bearing or clutch comprises a one way freewheel device.

In one embodiment the one-way rotational bearing or clutch comprises a sprag clutch.

The winder spool for the cutting line is mounted to the spindle.

It is preferred that the winder spool is demountable from the spindle. Magnetic means may be used to mount the spool to the spindle shaft.

The unit is provided with mounting means for mounting the unit to a glazing panel.

The mounting means preferably comprises one or more sucker devices.

It is preferred that one or more rotatable cutting line guide pulleys are positioned spaced from the spindle.

It is preferred that the unit comprises a plurality of spindle shafts for mounting respective cutting line spools spaced from one another.

Beneficially, a plurality of the spindle shafts comprise a respective ratchet device being mounted to the respective spindle shaft by means of a respective one-way rotational bearing or clutch. Preferably one spindle shaft has a one way bearing or clutch device arranged to permit rotation in an opposed sense to the direction of permitted rotation of another of the spindle shafts.

The invention will now be further described in a specific embodiment by way of example only and with reference to the accompanying drawings, in which;.

Referring to the drawings there is shown a cut out system particularly for use in cut out of bonded vehicle glazing panels such as windscreens.

The cut out system comprises a winder unit <NUM> including a pair of releasable suction cup mounts <NUM> enabling the winder unit to be releasably secured to the windscreen. The suction cup mounts comprise a rigid plastics cup <NUM> and underlying flexible rubber skirt membrane <NUM>. Respective actuation/release levers <NUM> enable consistent suction to be applied and released. Such suction mounts are commonly employed in windscreen replacement and repair technology. The suction cup mounts <NUM> are pivotably/tiltably mounted to the support chassis <NUM> of the winder unit to ensure that both mounts <NUM> can locate in good engagement with the windscreen despite the curvature of the windscreen. The main body of the support chassis <NUM> carries a pair of underslung winding spools <NUM>, <NUM> in side by side relationship. The spools are connected to axial spindle drive shafts which are supported in bearings provided on the winder unit. The spools <NUM>, <NUM> are driven axially rotationally either manually via a hand winder or by means of a mechanical actuator such as a motorised winding or winching tool. The manual or automatic driving tool is configured to engage with drive bosses which are provided at the opposite end of the drive shafts to the spools <NUM>, <NUM>. The drive shafts are compound structures comprising a number of interconnected components as will be described in detail later.

Positioned outwardly of the winding spools <NUM>, <NUM> are respective wire guide pulley wheels <NUM>, <NUM> of low friction plastics material. The pulley wheels are mounted to be rotatable about respective rotational axes. The guide pulleys rotate as the cutting wire is drawn tangentially across the pulleys as will be described.

To recap in the prior art the ratchet as shown schematically for <FIG> comprises a spring <NUM> loaded pawl <NUM> which engages in a recesses formed between teeth <NUM> in a ratchet collar mounted on the drive shaft of the spool drive mechanism. Teeth and intermediate recess for capturing the pawl <NUM> are provided entirely around the pawl collar. For purposes of explanation in <FIG> a single recess <NUM> is shown in which the pawl <NUM> can engage. The pawl <NUM> is provided with an angled slip surface <NUM> and the pawl can be lifted back against the spring <NUM> so as to be rotated about its axis to reverse the position of the slip surface through <NUM> degrees. These alternative positions are the `forward ratchet permitted' position and a 'reverse ratchet permitted' positions referred to earlier. In the configuration of <FIG> rotation is permitted in one direction only and in the other configuration (<FIG>) the reverse direction only. It is possible to hold the ratchet in the neutral position as shown in <FIG> in which rotation is permitted in either direction. Instead of 'teeth' the ratchet can comprise slots in an otherwise smooth surfaced cylinder. This is shown in the ratchet collar <NUM> in <FIG> which has smooth surface <NUM> interrupted by a series of axially extending spaced slots <NUM> to form the ratchet 'teeth'.

When the ratchet is operating in either the configuration of <FIG> each time, in the direction of permitted rotation, the pawl <NUM> lifts over the teeth as rotation is effected, effectively slightly compressing the spring <NUM> each time. This results in greater torque being required to effect rotation than would otherwise be the case for rotation without the ratchet.

The technique of <CIT> sseeks to improve upon prior art techniques (for example disclosed in <CIT> and <CIT> by utilizing slip cutting in a more controlled and consistent manner. In accordance with <CIT>, a loop of the cutting line is formed around the periphery of the entire windscreen <NUM> in the set up procedure and the cutting line is attached at opposed ends to each of the respective winders spools.

In setting up, the winder unit is initially provided (loaded) with a significant length of the line already wound onto the respective winder spools and positioned on the inside of the windshield. The winder spool ratchets are toggled to the ratchet position which permits the cutting line to be drawn off the respective winder spools and line is pulled off the loaded unit, separate lengths 41a 41b being drawn around pulleys <NUM>,<NUM> crossed over as shown in <FIG>. A pinched apex 41c of the loop of line <NUM> is drawn out and pushed through a hole formed in the PU bonding bead. Thus the pinched apex 41c of the line <NUM> is drawn from inside to outside the vehicle, at a position below the winder unit <NUM>.

Next the loop of the line is expanded and looped around the entire periphery of the windshield <NUM> externally of the vehicle and positioned adjacent the PU bead. This is shown in <FIG>, where the unit <NUM> is positioned internally of the vehicle and the lengths 41d 41e are also internally but the remainder of the loop 41f is externally of the vehicle. When in position as shown in <FIG>, the winder spools can be operated as described above to slip cut the PU bead and release the windscreen from the supporting frame.

In the cut out procedure when winding in on one of the winder spools <NUM>, <NUM> the other is configured to allow the cutting line to be drawn off the respective spool. In other words the line is attached to both spools during the cutting procedure and slip is achieved by permitting winding off from one of the spools as the line is wound on to the other. As a result there can be constant slip cutting throughout substantially the entire process (certainly for the majority of the cut out process). This is achieved by means of toggling the ratchet mechanisms. The ratchets of the respective winder mechanism are toggled between a `forward ratchet permitted' position - <FIG> and a 'reverse ratchet permitted' - <FIG> position (or a ratchet off/neutral position - <FIG>) to enable winding onto or off a respective winder spool <NUM>, <NUM> during the cut out procedure. When the ratchet is operating in either the configuration of <FIG> each time, in the direction of permitted rotation, the pawl lifts over the teeth as rotation is effected effectively slightly compressing the spring each time. This results in greater torque being required to effect rotation than would otherwise be the case for rotation without the ratchet. More winding effort is therefore required which can be significant when added to the friction resistance caused by the line cutting through the bonding bead.

The present invention provides an improvement over the known prior art cutout devices by utilizing for the drive shaft spindle that drives the spools <NUM>, <NUM> a rotational directional control mechanism which comprises <NUM> one-way rotational control devices cooperating in concert. For example the rotational directional control mechanism comprises a ratchet mechanism that can be selectively applied but which also comprises a one way clutch or bearing mounted to the shaft.

Referring to <FIG> and <FIG>, the drive spindle <NUM> includes a spindle shaft <NUM> for mounting the spool. The spindle shaft is connected at its other end to the drive boss <NUM>. A cylindrical stator mounts the drive spindle <NUM> to the chassis <NUM> of the winder unit. Flange bearings <NUM>, <NUM> connect the stator to the drive shaft spindle. A magnet <NUM> is provided in a recess of a quick change spool to permit mounting to the drive shaft spindle. Other means of mounting may be used. The drive boss <NUM> as shown is fixed using a wave spring washer <NUM> and a machine screw <NUM> to the drive shaft spindle.

A one way rotational clutch or bearing <NUM> mounts the ratchet collar <NUM> to the spindle shaft <NUM>. The ratchet collar is the item provided with the ratchet teeth and recesses extending around the collar. This feature enables rotation of the spindle shaft <NUM> to be governed or constrained by two means operating in concert, namely the one way clutch or bearing <NUM> and the ratchet mechanism (pawl <NUM> engaging in the slots <NUM> between the 'teeth' <NUM> on the ratchet collar <NUM>). The one way clutch or bearing <NUM> acts such that torque is only transmitted between the drive shaft spindle and the mounted ratchet collar with rotation in one direction only. Such one way rotation devices are known in the art, for example as a sprag clutch or one way freewheel clutch. A sprag clutch operates in a similar way to a roller bearing, but instead of cylindrical rollers, non-revolving asymmetric figure-eight shaped sprags are used. When the unit rotates in one direction the asymmetric sprags slip or free-wheel to enable the spindle shaft <NUM> to rotate in that direction, but when a torque is applied in the opposite direction, the sprags tilt slightly, producing a wedging action and binding because of friction as a frictional engagement will be formed by the wedging action of the respective sprags on the spindle shaft <NUM> and the ratchet collar <NUM> to restrict movement in the opposite direction. The sprags are usually spring-loaded so that they lock with very little backlash.

As a result of such a mounting arrangement rotation of the drive spindle shaft can be controlled by the ratchet mechanism <NUM> (pawl <NUM> and ratchet collar <NUM>) operating in concert with the one way clutch or bearing device <NUM>. The impact of this is:.

The drive shaft spindles 61for the separate respective spools <NUM>, <NUM> have one way bearing or clutch devices arranged to permit rotation in opposed senses.

Claim 1:
A winder unit (<NUM>) for winding cutting line, the winder unit comprising:
a rotatable spindle shaft (<NUM>) for winding;
a ratchet device (<NUM>); and
mounting means (<NUM>) for mounting the winder unit (<NUM>) to a glazing panel, characterized in that:
the ratchet device (<NUM>) is mounted to the spindle shaft (<NUM>) by a one-way rotational bearing or clutch (<NUM>).