GB2156734A - Press - Google Patents

Abstract

A press 20 for sealing e.g. double-glazed window units comprises a bottom platen 24 for receiving a workpiece 28, a top platen 25 pivotally movable relative to the bottom platen between an open position in which the platens are widely spaced apart for receiving a workpiece to be pressed and a closed, operative position in which the platens are contiguously disposed for engaging the workpiece. The press includes latches 30, 31 for securing the platens together in the operative position, and a pneumatic ram (41, Fig. 4) connected by way of a mechanical linkage (42-60, Fig. 4) to both the platens to apply pressure to the bottom platen 24 to displace it so as to press in use the workpiece 28 against the top platen 25 as well as to effect the movement of the top platen 25 relative to the bottom platen 24. <IMAGE>

Description

SPECIFICATION Press The present invention concerns a press. Al though the invention is not so restricted, it will hereafter be described with reference to its preferred application, namely to a sealing press for sealing double or multiple glazed units prior to the insertion of such units within window or door frames.

Known double-glazed units comprise a per ipheral aluminium spacer bar positioned be tween and secured to a pair of glass sheets, at a location somewhat inboard of the outer edges of the sheets. The bar is a channel shaped hollow extrusion and contains a desic cant to absorb any moisture in the space between the sheets. A 'hot melt' adhesive (i.e.

one that is solid at room temperature but liquefying on application of elevated temperatures), e.g. a butyl rubber, is then applied around the periphery of the unit to seal it. The application of the adhesive is a manual oper ation requiring considerable skill, labour and time. This face limits productivity and repre sents an important disadvantageous cost factor. Also, the fabrication, cutting to length and positioning of the spacer bar all increase the complexity, labour content and expense of the total manufacturing process of the units.

In more recent times an 'all-in-one' sealant tape has become available in reel or coiled form. This tape eliminates the need for the spacer bar. The body of the tape contains or has dispersed therein the desiccant, adhesives as well as a sinuous strip of metal. The tape is placed between the two sheets of glass which are then pressed together with sufficient pressure to deform the body of the tape to the desired thickness, and to adhere the tape to the sheets in a permanent fashion. Thus, the development of the 'all-in-one' sealing strip has necessitated the development of efficient, accurate and relatively inexpensive sealing presses which are safe and reliable in operation.

A sealing press is known which has a stationary, horizontal bottom platen co-operable with a displaceable top platen. Separate pneumatic rams are employed to perform the raising and lowering of the top platen relative to the bottom platen, on the one hand, and the inflation of the inflatable elements provided in the bottom platen to press workpiece(s) loosely resting on them, via a plate against the top platen. The top and bottom platens are latched together but the latching is performed manually. The claimed accuracy of this press is only of the order of + 2mum and furthermore has the inconvenience of requiring wooden battens to act as spacers within the press to achieve this.

The present invention seeks to provide a sealing press for glazing units which eliminates or substantially reduces the disadvantages of the known sealing press.

According to one non-limiting aspect of the present invention there is provided a press comprising a bottom platen for receiving a workpiece, a top platen movable relative to the bottom platen between an open position in which the platens are widely spaced apart for receiving one or more workpieces to be pressed and a closed, operative position in which the platens are contiguously disposed for engaging the workpiece(s), securing means for securing the platens together in said operative position, and pressure application means connected to both said platens and adapted to apply pressure to the bottom platen (or a part thereof) to displace it so as to press in use the workpiece(s) against the top platen as well as to effect the movement of the top platen relative to the bottom platen.

Preferably, the connection between the pressure application means and the platens is a mechanical linkage of high mechanical advantage.

Expediently, the said linkage is connected to mechanical latch means constituting the said securing means in such a manner that latching takes place automatically on attainment by the top platen of its operative position.

Electric and/or electronic control means may be provided to permit an operator to select a platen spacing and to adjust the operative position of the bottom platen relative to the top platen in accordance with the selected spacing to accommodate workpieces of differing final thicknesses. Control means may include or be connected to sensing means for sensing the displacement of the bottom platen.

Preferably, the pressure application means is a fluid pressure operated ram which is connected to said linkage. Although a single ram and a suitably formed linkage may be provided, in a preferred embodiment a pair of ground-engaging legs are attached to the bottom platen and the legs form both a pedestal and a casing for a respective ram and linkage.

In a preferred embodiment the linkage includes a pair of push rods disposed, respectively, at the front and at the back of the bottom platen and the push rods are connected for synchronous operation by a link rod.

In an advantageous embodiment, the control means includes means for synchronising the operation of the pressure application means in each leg. The synchronising means may include position-sensing transducers effective to stop one of the pressure application means (rams) which is in advance of the other pressure application means (ram). Thus, for instance, the linkage of each leg, i.e. of each pressure application means may carry a magnet co-operable with reed switches positioned at fixed iocations, closure of a switch under the effect of the magnet reaching its proximity being effective to energize electric circuitry to stop further application of pressure until the corresponding reed switch of the other leg has also closed.Furthermore, the said circuitry may include means for automatically actuating a reverse sequence of depressurising the linkage, unlatching and raising the top platen to allow unloading the workpieces.

A preferred embodiment of the invention will now be described, purely by way of example, with reference to the accompanying diagrammatic drawings, wherein: Figure 1 is a cross-sectional view of two sheets of a double-glazed unit with 'all-in-one' sealing tape therebetween.

Figure 2 is a perspective view, taken from the front, of a press according to the invention in its open, ready-to-be-loaded position, loaded with units to pressed.

Figure 3 is a view corresponding to Fig. 2 but showing the press in its closed, operative position, arrows indicating the direction of application of pressure forces, Figure 4 is a side elevation of the press with the cover of one of the legs removed to reveal the working components therein, and showing the position before the start of its cycle of operation, and Figures 5 and 6 are views corresponding to Fig. 4 but showing the press in its midforward cycle and end-of-forward-cycle positions, respectively.

Referring first to Fig. 1 of the drawings, a double glazing unit consists of two parallel sheets of glass 10, 11 with a piece of sealing tape 12 therebetween, the gap between the sheets 10, 11. The tape 1 2 is a commercially available product made of rubber impregnated with a desiccant to absorb any moisture present in the gap between the sheets 10, 11 as well as with an adhesive for sealingly adhering the tape 12 to the sheets 10, 11. In addition, the tape 1 2 contains a thin, corrugated strip 1 3 of metal acting as a shape retainer and moisture creep barrier. Arrow 14 indicates that the sheets 10, 11 require to be pressed together to effect bonding of the tape 1 2 to the glass, by means not shown in Fig.

1.

A press 20 for carrying out the pressing together is illustrated in Figs. 2 to 6.

Fig. 2 shows the main components of the press 20. A pair of like box-shaped supports or legs 22 encased in covers 23 carry a horizontal bottom platen 24 and a top platen 25 which is pivotable between its position shown in Fig. 2 and a horizontal position shown in Figs. 5 and 6. A console 26 extends between the legs 22 at the front of the press.

A plurality of unsealed double glazed units 28 of varying shapes and sizes are shown loaded on the bottom platen 24, ready to be pressed.

Through openings in the bottom platen 24 a pair of spaced apart male latch members 30 secured to the legs 22 extend upwardly for co-operation with female latch members 31 carried by the top platen 25.

Each platen 24, 25 is a steel box structure the working surfaces of which are covered by a suitable insert or lining 32 of soft, material, e.g. felt-covered chipboard, to prevent damage to the glass surfaces of the units 28.

The console 26 includes a number of actuating press-buttons including dual 'seal' buttons, both of which require depression to initiate operation, an 'emergency stop' button, an 'automatic sequence reversal button', as well as other buttons and/or visual and/or audible indicators and warning lights.

Fig. 3 shows the top platen 25 in its hinged-down horizontal position and the two platens 24, 25 secured together by the latches 30, 31. Arrows 35 indicate that in operation the top platen 25 is fixed in position and the bottom platen 24 is pressed against it.

The press stroke and the means for achieving it is better seen in Fig. 4. The legs 22 are identical in mechanical function except that one leg contains an electro-pneumatic emergency stop system which, however, does not form part of the invention. Therefore only one leg 22 will be described in detail.

The leg 22 comprises a rectangular frame 40. A pneumatic ram 41 is articulated to the bottom frame member 42 at 43. On energisation from a source of compressed air, not shown, the rod 44 of the ram extends in the direction shown by arrows 45.

The rod 44 is linked via a sliding coilar 46 to one end of an arm 47 the other end of which is articulated to one end of a link arm 48. The other end of the arm 48 is secured to the rear of the top platen 25. The central part of arm 48 has a transversely extending portion pivoted at 50 to a flange 51 secured to the top frame member 52. The arm 48 passes through a slot 53 formed in the rear vertical frame member 54. In this way, extension of the rod 44 causes the top platen 25 to hinge downwardly to its operative position.

One end of a link rod 56 is connected to the rod 44 via arm 70. Its other end is connected to one end of a press arm 58 pivoted at 72 on flange 66 secured to top frame member 52. The other end of press arm 58 carries a cam follower roller 60 that is in engagement with a cam track 61 on one end of an L-shaped latch arm 63 the other end of which extends through the bottom platen 24 and terminates in the latch members 30. Thus, in addition to the abovedescribed effect of lowering the top platen 25, extension of the ram rod 44 is effective also to put the latch into its receiving condition.

The latch arm 63 is connected by a spring 65 to a flange 66 secured to the top frame member 52 and pivots about point 77.

Fig. 5 shows the press with the top platen 25 fully down. The press (compression) stroke now commences. The arm 47 now remains stationary and the rod 44 slides through a bearing (not shown) within the pivot 67 linking the rod 44 and the arm 47. The end of the rod 44 is pivotally connected to one end of the rear press arm 70 as well as to the above-mentioned front press arm 58 via the link 56. The other ends of press arms 58, 70 are pivoted, respectively, to the flanges 66, 51 at points or joints 72, 73. The bottom ends (as viewed) of push rods 75, 76 bear on the ends of the press arms 58, 70, respectively, while the bottom platen 24 rests on their upper ends. Thus rotation of the press arms about the points 72, 73 causes the push rods 75, 76 to rise and so press the bottom platen 24 against the latched top platen 25.

Fig. 6 shows the ram rod 44 fully extended and the press stroke finished. An electronic sensor unit 78 controls the exact termination point and is coupled to another electronic controller, settable at the console, for adjusting the stroke to different thicknesses of the workpiece, raising or lowering the bottom platen, as appropriate.

As already mentioned in the introductory portion of the specification, an electronic circuit is provided to synchronise the operation of the two rams and linkages in each leg 22, i.e. to allow a lagging ram and linkage to catch up. This permits the press to compensate for asymmetrically placed and/or unevenly thick workpieces and prevents the 'auto reverse' stroke starting until both arms 41 have reached the final size required, as set on the control console 26.

It will be appreciated that the illustrated press described above has a number of important advantages: one ram per leg effects pressing, latching and moving of the top platen; -the operation between loading and unloading is fully automated; -accuracy may be of the order of tenths of millimetres; -the final required unit thickness is programmable into the machine which then presses the units automatically to this preset figure, without the use of any distance pieces laid between the platens; double or triple glazed units of enormously varying sizes can be processed from small window units to large patio doors; ; -a facility (not illustrated) within the bottom platen allows easy 'roll in' loading of patio door-sized units, e.g. in the form of a roller or castor bed; -a modular construction system allows easy disassembly and packaging for export, as well as repair and maintenance; and -a press pressure of seven tons is obtained by a lever ratio advantage converting the already large pressure from the rams to a very high force obtained from a simple compressor supply.

Claims (12)

1. A sealing press comprising a bottom platen for receiving a workpiece, a top platen movable relative to the bottom platen between an open position in which the platens are widely spaced apart for receiving one or more workpiece(s) to be sealed and a closed, operative position in which the platens are contiguously disposed for engaging the workpiece(s), securing means for securing the platens together in said operative position, and pressure application means connected to both said platens and adapted to apply pressure to the bottom platen (or a part thereof) to displace it so as to press in use the workpiece(s) against the top platen as well as to effect the movement of the top platen relative to the bottom platen.

2. A press according to claim 1, wherein the connection between the pressure application means and the platens is a mechanical linkage of high mechanical advantage.

3. A press according to claim 2, wherein the said linkage is connected to mechanical latch means constituting the said securing means in such a manner that latching takes place automatically on attainment by the top platen of its operative position.

4. A press according to any preceding claim, wherein electric and/or electronic control means are provided to permit an operator to select a platen spacing and to adjust the operative position of the bottom platen relative to the top platen in accordance with the selected spacing to accommodate workpieces of differing final thicknesses.

5. A press according to claim 4, wherein said means includes, or is connected to, sensing means for sensing the displacement of the bottom platen.

6. A press according to claims 1 and 2, wherein the pressure application means is a fluid pressure-operated ram which is connected to said linkage.

7. A press according to claim 6, wherein a pair of ground-engaging legs are attached to the bottom platen and the legs form both a pedestal and a casing for a said, or respective ram and linkage.

8. A press according to claim 2 or any claim appendant thereto, wherein the linkage includes a pair of push rods disposed, respectively, at the front and at the back of the bottom platen and the push rods are connected for synchronous operation by a link rod.

9. A press according to claims 4 and 7, wherein the control means includes means for synchronising the operation of the pressure application means in each leg.

10. A press according to claim 9, wherein the synchronising means includes position sensing transducers effective to stop one of the pressure application means (ram) which is in advance of the other pressure application means (ram).

11. A press according to claim 10 and claim 2, wherein the linkage of each leg includes a magnet co-operable with reed switches positioned at fixed locations, closure of a switch under the effect of the magnet reaching its proximity being effective to energize electric circuitry to stop further application of pressure until the corresponding reed switch of the other leg has also closed.

12. A press according to claim 11, wherein the said circuitry includes means for automatically actuating a reverse sequence of depressurising the linkage, unlatching and raising the top platen to allow unloading of the workpieces.

1 3. A sealing press substantially as herein described with reference to and as shown in the accompanying drawings.