GB1583111A

GB1583111A - Materials handling apparatus

Info

Publication number: GB1583111A
Application number: GB25172/77A
Authority: GB
Original assignee: HALL AUTOMATION Ltd
Current assignee: HALL AUTOMATION Ltd
Priority date: 1978-05-09
Filing date: 1978-05-09
Publication date: 1981-01-21

Description

(54) MATERIALS HANDLING APPARATUS (71) We, HALL AUTOMATION LIMITED, a British Company, of Wiggenhall Industrial Estate, Watford, Hertfordshire, WED 1 8AP, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to materials handling apparatus and more particularly to apparatus for centralising an item of material with respect to a reference position.

According to the present invention, apparatus for centralising an item of material comprises two toothed racks which respectively mesh with regions of a rotatable pinion operable to drive the racks in opposite directions and means for supporting the item of material so that, when the racks are driven, its opposite ends can be respectively engaged by members connected to the racks, in order to centralise said item with respect to a reference position.

The pinion may be connected to a further pinion which meshes with a further toothed rack which is itself driven by a prime mover, e.g. in the form of a pneumatic or hydraulic actuator. Advantageously the two pinions are connected through a disengageable coupling or clutch whereby, when the coupling or clutch is disengaged, the two toothed racks can be moved independently of the driving rack in order to adjust the distance between the members so as to accommodate items of material of different length.

The rotatable pinion operable to drive the racks may comprise two axially spaced pinion portions which are rotatable together about a common axis. In this case one toothed rack may mesh solely with one pinion portion and the second toothed rack may mesh solely with the other pinion portion.

The apparatus may be particularly employed for centralising a sheet of material with respect to a carrier and in such an application the sheet of material is supported, e.g. by rollers, during the centralising operation and the rollers are operable to lower the sheet on to the carrier when the centralising operation has been carried out and to retract so that the carrier bearing the centralised sheet can be moved to a processing station at which it will be accurately positioned by virtue of the centralising operation.

A specific application of the apparatus according to the invention is for centralising glass sheets such that two or more sheets may subsequently be accurately positioned for bonding together in order to form a laminated structure, such as a windscreen for a vehicle.

According to a feature of this aspect of the invention, the apparatus is arranged to centralise alternately an annealed glass sheet of one size and a toughened glass sheet of another size and such a pair of sheets are subsequently bent to a curved shape and bonded together by a plastics interlayer in order to form a windscreen in which the toughened glass sheet is the inner layer.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagram in elevation showing the principle of operation of a machine according to the invention, Figure 2 is a diagram in plan showing the drive arrangement for the mechanism in Figure 1, Figure 3 is a perspective view of one embodiment of apparatus according to the invention, Figure 4 is a view from above of part of the apparatus in Figure 3, Figure 5 is a fragmentary side view of part of the apparatus in Figure 3, and Figure 6 is a diagram showing one form of pneumatic control system for the apparatus of Figure 3.

Referring to Figures 1 and 2, an apparatus for centralising an item of material with respect to a centre line CL comprises two toothed racks 1 and 2 which respectively mesh with opposite sides of a rotatable pinion 3 and which are constrained to move linearly and parallel to each other. Each rack carries at its outer end a carriage 4 provided with a roller 5. The pinion 3 is connected through a dog clutch 6 to a further pinion 7 which engages with a drive rack 8 driven by a pneumatic actuator 9.

Thus, when the actuator 9 drives the rack 8, the pinion 7 drives the pinion 3 so that the racks 1 and 2 move in opposite directions by precisely equal amounts. Hence the two carriages 4 connected to the racks are always equidistant from the centre line CL, as is indicated by the two equal and equally variable distances Al and A2.

The movement of the centralising carriages 4 is limited by the stroke of the actuator 9 driving the rack 8, but by disengaging the dog clutch 6, the range of the distances Al and A2 between the centralising carriages 4 can be altered by moving the racks 1 and 2 without moving the drive rack 8. Such an arrangement enables the apparatus to accommodate a greater range of items to be centralised than would otherwise be the case.

An embodiment of apparatus according to the invention and intended particularly for centralising glass sheets, which are subsequently to be laminated together to form a windscreen, will now be described with reference to Figures 3 to 6.

In such an application, the apparatus is required to centralise pre-shaped sheets of annealed glass and toughened glass so that they can be very accurately located in a bending fixture to within 10 thousandths of an inch. After hot bending a sheet of annealed glass is bonded as an outer layer to a sheet of toughened glass as an inner layer by means of a plastics interlayer in order to form a curved windscreen. Since the sheet of annealed glass forms the outer layer of the windscreen, it is made of a larger size than the sheet of toughened glass forming the inner layer, such that when both sheets are bent to the required curvature, their edges are virtually flush with one another. The windscreen so produced requires no finishing and in particular no edge trimming or grinding after the laminating operation; since the sheets have been very accurately located with respect to each other by means of the centralising apparatus according to the present invention.

Referring to Figures 3 to 5, corresponding parts bear the same references as in Figures 1 and 2. Thus the apparatus comprises a base unit 10 which supports a horizontal beam 11.

At each end of the beam is a sliding carriage 4 which can slide on rails 12 parallel to the plane of the glass sheets to be centralised.

Each carriage includes a roller 5 mounted on a swinging arm 4a.

The two carriages are respectively connected to the outer ends of toothed racks 1 and 2 which are mounted on the beam 11 so as to move linearly and parallel to each other.

The driving mechanism for the racks 1 and 2 comprises the pneumatic actuator 9 which drives the rack 8, which is in turn connected through the pinion 7, dog clutch 6 and pinion 3 (as shown in Figure 2) to drive the racks 1 and 2 so that they move in opposite directions by equal amounts. Mounted in the centre of the beam 11 is a structure 13 which supports the glass sheets S whilst they are being centralised with respect to a carrier 17 (Figure 5). This structure 13 must be retractable so that once a glass sheet S has been centralised on its carrier 17, the latter is able to transfer the glass sheet to the bending and laminating stations.

More specifically the structure 13 includes support rollers 14 mounted on swinging arms 14a which are carried by the structure 13. The latter is mounted on a pneumatic actuator 15 for vertical movement and incorporates a pneumatic actuator 16 for horizontal movement.

In operation, a sheet of glass S to be centralised is delivered, e.g. by an overhead mechanism, so that the lower edge of the glass can be lowered on to the support rollers 14. This causes the arms 14a to pivot thereby closing a microswitch 14b which in turn operates a circuit to cause the glass sheet to be released from the overhead mechanism.

The sheet of glass is slightly inclined to the vertical e.g. at 2 degrees and in this position it rests against pads (not shown).

The actuator 9 is now operated to cause the toothed racks 1 and 2 to move the carriages 4 inwards until one of the rollers 5 engages an edge of the glass and gently pushes it to the centralised position. When both the rollers 5 have touched the edge of the glass, the swinging arms 4a pivot thereby closing two microswitches 4b which control the pneumatic supply so that the actuator 9 is operated to retract the carriages 4 to their starting position.

The pneumatic actuator 15 is now operated to lower the structure 13 and hence the rollers 14 until the sheet of glass rests in the carrier 17 with respect to which it is now accurately positioned. The pneumatic actuator 16 retracts the rollers 14 horizontally, whilst actuators 18 retract the centralising rollers 5, to enable the carrier 17 and the sheet of glass carried thereby to be transported to the bending station.

It will be appreciated that if sheets of annealed and toughened glass are alternately fed to the centralising apparatus and are each centred and positioned on a carrier which itself is accurately located with respect to the apparatus, then successive sheets of glass will be delivered by the carriers to the bending station in accurately positioned relationship with respect to each other.

Figure 6 is a diagram of the pneumatic control system for the apparatus of Figures 3, 4 and 5. The actuators 9, 15, 16 and 18 are shown, together with their control valves 19a, l9b, 19c, and the pneumatic supply input 20. The control valve 19a controls the actuator 16 providing horizontal movement to the structure 13, whilst the control valve 19b controls both the actuator 15 providing vertical movement to the structure 13; as well as the actuator 18 controlling retraction of the centralising rollers 5. The control valve 19c controls the actuator 9 for the driving rack 8 as well as a pair of clamps 21 for clamping the rollers 14 against rotation whilst they are supporting a sheet of glass.

Whilst the apparatus of the invention has been particularly described for centralising glass sheets, it will be appreciated that it may equally well be employed for centralising other items.

WHAT WE CLAIM IS: 1. Apparatus for centralising an item of material comprising two toothed racks which respectively mesh with regions of a rotatable pinion operable to drive the racks in opposite directions and means for supporting the item of material so that, when the racks are driven, its opposite ends can be respectively engaged by members connected to the racks, in order to centralise said item with respect to a reference position.

2. Apparatus as claimed in claim 1, wherein the pinion is connected to a further pinion which meshes with a further toothed rack which is itself driven by a prime mover.

3. Apparatus as claimed in claim 1 or 2, wherein the first mentioned pinion is connected to its drive means through a disengageable coupling or clutch whereby, when the coupling or clutch is disengaged, the two toothed racks can be moved independently of the drive means.

4. Apparatus as claimed in any of the preceding claims, wherein the two toothed racks are constrained to move substantially linearly and parallel to each other.

5. Apparatus as claimed in any of the preceding claims, wherein each rack carries a carriage provided with one of said members for engaging the item of material to be centralised.

6. Apparatus as claimed in claim 5, wherein each member is a roller.

7. Apparatus as claimed in claim 5 or 6, wherein each carriage is mounted on a rail so that the carriage slides on the rail in the direction of movement of the associated rack.

8. Apparatus as claimed in any of the preceding claims, wherein the means for supporting the item of material comprises a retractable structure.

9. Apparatus as claimed in claim 8, wherein the retractable structure includes two spaced support members each in the form of a roller.

10. Apparatus as claimed in claim 9, wherein each support roller is mounted on a movable arm which moves when an item of material is positioned on the support members, such movement enabling initiation of the operation of the apparatus to centralise said item of material.

11. Apparatus as claimed in claim 8, 9 or 10, further comprising a carrier for carrying the centralised item of material after the means for supporting said item of material has been retracted.

12. Apparatus as claimed in any preceding claim, wherein said members are movably mounted so that when the members have engaged the item of material at opposite ends thereof, whereby said item of material is in the centralised position, movement of said members causes actuation of means to retract the racks to their starting positions.

13. Apparatus as claimed in claim 12 as dependent on claim 5, 6 or 7, wherein each member is mounted on an arm movable with respect to the associated carriage.

14. Apparatus as claimed in any pre ceding claim, wherein the operation of the apparatus is effected by pneumatic or hydraulic actuators.

15. Apparatus as claimed in any preceding claim, wherein in the rotatable pinion operable to drive the racks comprises two axially spaced pinion portions which are rotable together about a common axis.

16. Apparatus for centralising an item of material substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

17. Apparatus for centralising items of sheet material substantially as hereinbefore described with reference to Figs. 3 to 6 of the accompanying drawings.

18. A method of manufacturing a vehicle windscreen which comprises the steps of alternately centralising a sheet of annealed glass and a sheet of toughened glass by means of apparatus as claimed in any preceding claim, hot bending each of said sheets to a curved shape and bonding said sheets together by means of a plastics interlayer in order to form a curved windscreen in which the sheet of toughened glass is the inner layer.

19. A vehicle windscreen produced according to the method of claim 18.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. control system for the apparatus of Figures 3, 4 and 5. The actuators 9, 15, 16 and 18 are shown, together with their control valves 19a, l9b, 19c, and the pneumatic supply input 20. The control valve 19a controls the actuator 16 providing horizontal movement to the structure 13, whilst the control valve 19b controls both the actuator 15 providing vertical movement to the structure 13; as well as the actuator 18 controlling retraction of the centralising rollers 5. The control valve 19c controls the actuator 9 for the driving rack 8 as well as a pair of clamps 21 for clamping the rollers 14 against rotation whilst they are supporting a sheet of glass. Whilst the apparatus of the invention has been particularly described for centralising glass sheets, it will be appreciated that it may equally well be employed for centralising other items. WHAT WE CLAIM IS:

1. Apparatus for centralising an item of material comprising two toothed racks which respectively mesh with regions of a rotatable pinion operable to drive the racks in opposite directions and means for supporting the item of material so that, when the racks are driven, its opposite ends can be respectively engaged by members connected to the racks, in order to centralise said item with respect to a reference position.

6. Apparatus as claimed in claim 5, wherein each member is a roller.

19. A vehicle windscreen produced according to the method of claim 18.