GB2223039A - Sheet spreading device - Google Patents

Abstract

A sheet spreading device in which a sheet is fed with its centre generally on the centreline (16) of the device, comprises two forward endless belt drives (17, 18) mounted symmetrically to either side of the centreline 16 and two rearward endless belt drives (19, 20) mounted immediately behind the respective forward belt drives. The adjacent inner runs (25a, 32a) of the forward and rearward belt drives on each side of centreline 16 lie parallel, are spaced by a small gap and move in the direction away from the centreline 16. A multiplicity of spaced rotary cams (40) (belt oscillators) engage periodically the inner belt runs (25a) and comprise drums, each having a rounded diamond shape periphery (42). The drums are driven in synchronism with the belt drives to move portions of inner belt runs 25a towards those of belt 32a to "nip" the belts and therefore portions of the sheet between the belts at spaced locations to spread the sheet as inner runs 25a, 32a move away from centreline 16. Inner runs 32a of belt 32 have supports 52, 53 and may also include the cams 40. <IMAGE>

Description

IMRPOVEMENTS IN OR RELATING TO SHEET SPREADING DEVICE This invention relates to a device for spreading sheets and the like in preparation for an operation to be carried out thereon in their spread form. For example the device is particularly applicable to spreading sheets for use in laundry equipment such as an ironing machine.

In ironing an article, such as a sheet in a laundry, a leading edge of the article is fed into the ironer rollers and the article is then drawn through the rollers. Steps must be taken to ensure that the trailing part of the article is substantially free from rucks and folds before passing between the ironer rollers. The present invention seeks to provide an improved spreading device through which the trailing part of the article may be drawn as it is fed to the ironer. The device may be used if the sheet is fed by hand to the ironer but is particularly suitable for use in conjunction with an automatic feeding system.

My U.S. Patent Specification No. 3,431,665 describes and illustrates a device for spreading a sheet or the like which is drawn through the device with its centre on a centreline of the device. The device comprises two pairs of endless belts positioned symmetrically with one pair on each side of the centreline of the device and with the belts of each pair spaced on either side of a common plane extending through the centreline of the device. Thus each belt has an inner run which faces the inner run of the other belt of the pair. The belts of each pair are driven in contra-rotating fashion with the inner runs of the belts in each pair moving outwardly from the device centreline.Belt deflectors are mounted adjacent the ends of one inner run of each pair of belts and are oscillated transversely to said common plane to displace the inner run of the belts periodically towards the inner run of the other belts. The belt displacing means of the two pairs of belts are inter-linked to synchronise the movements of the inner runs together. Periodic movement of the inner runs together causes the side portions of the sheet between the belts runs to be periodically gripped to spread the sheet apart between the belts. In practice it is found that this arrangement is not entirely satisfactory. The long lengths of belt between the belt deflectors apply little or no grip to the sheet so that the sheet is not gripped evenly between the sheets with the result that the sheet is no spread evenly by the belts and may be folded or puckered as it is fed to the ironer.Also, unless the deflectors of the inner belt runs are precisely synchronised, the alternate gripping of the sheet first between one of the pair of belts and then between the other causes the sheet to be drawn first to one side of the centreline and then the other thereby misaligning the sheet with the ironer. Improved operation is obtained if the belts are arranged to close on the sheet at an increased frequency with the belts running at higher speeds.

However, because of the flexiblity of the belts and the length of unsupported belt between the deflectors, they tend to whip and snake as they are deflected and slap together in an incontrolled manner snatching the sheet rather than lightly and momentarily gripping the sheet. Also the belts become very noisy when run at speed.

The invention provides a device for spreading a sheet or the like which is fed with its centre generally on a centreline of the device, the device comprising two pairs of endless belts positioned symmetrically with respect to the centreline, one pair on each side of the centreline, each belt having an inner run which faces the inner run of the other belt of the pair, driving means coupled to said belts for driving the belts in contra-rotating fashion with the inner runs thereof moving away from said centreline and belt deflector means engageable with the inner runs of one belt of each pair at a multiplicity of spaced locations for periodically closing said inner runs in synchronism together to "nip" side portion of the sheet at spaced locations between the inner runs of the belt and thereby spread the sheet between the inner runs of the endless belt.

With this arrangement the belts may be run at high speed and the sheet belts deflected at high frequency to provde a pulsating action on the inner runs of the belts engaged by the deflector means to provide momentary grip of the sheet between the belts at said multiplicity of locations along the belts and then release. The belts run in a controlled quiet manner and smooth spreading of the sheet between the belts is obtained without any tendency to draw the sheet off centre.

The following is a description of a specific embodiment of the invention, with reference being made to the accompanying drawings in which: Figure 1 is a front elevation view of part of a laundry article feeding apparatus embodying a sheet spreading device in accordance for the invention; Figure 2 is a similar view to Figure 1 with front covers and parts of the spreader mechanism removed; Figure 3 is a plan view of the spreading device of Figure 1; Figure 4 is a plan view of part of the spreading device shown in Figure 3 in greater detail; Figure 5 is a more detailed view of part of spreading device; Figure 6 is a section inthe direction of arrows 6-6 of Figure 4; and Figure 7 is a detailed view of part of a drive mechanism for the spreading device.

Referring firstly to Figures 1 to 3 of the drawings, there is shown a sheet spreading device to be installed at the entry or feed end of a laundry ironer or other similar piece of equipment. A pair of corners of the sheet at the leading end of the sheet is supported and drawn apart across the entry to the ironer by means of a sheet handling apparatus as described and illustrated in my U.K. Patent Application No. 8810683 to which reference should be made. The sheet is suspended at its leading end from the handling apparatus and the side portions of the trailing or body part of the sheet are received in and drawn apart to spread the sheet by means of the sheet spreading device which will now be described.

The device comprises an elongate enclosure mounted on a base to extend across the feed end of the inner or other launching equipment and comprises a pair of upright frame members 10, 11 each rigidly mounted on horizontal frame members 12, 13. The upright frame members 10, 11 are interconnected by a rear cross member 14 and a front cross member 15.

A vertical centreline of the device is indicated at 16 and two forward endless belt drives 17,18 are mounted symmetrically on the cross member 15 to either side of the centreline. Two rearward endless belt drives 19,20 are mounted immediately behind the respective forward belt drives 17,18 on columns 8 and 9 mounted on frame members 12, 13 and further frame members 21, 22 are "canti-levered" out from columns 31 to support the adjacent inner ends of the belt drives. The rearward endless belt drives 20 are also symmetrically disposed with respect to centreline 16 and are somewhat shorter than the forward belt drives 17,18, leaving the latter to project beyond the rearward belt drives towards the centreline 16. One pair of forward and rearward belt drives, 17,20 will now be described in greater detail, it being understood that the other pair are of identical construction.

The forward belt drive 17 comprises an endless belt 25 extending between the drive pulley 26 mounted on the cross member 15 adjacent the upright 10 and an idler pulley 26a mounted on the cross member adjacent the centreline 16. The drive pulley 26 is connected to a vertically extending drive shaft 27 supported in a bearing housing 28 on the cross member 15 and a further bearing housing 29 on the base 12. The lower end of the drive shaft 27 projects into the hollow frame member 12 and a toothed wheel 30 is secured to the end of the drive shaft.

The rearward endless belt drive 20 is supported at its outer end on column 31 and at its inner end on canti-lever mounted frame member 21 to extend parallel to the forward belt drive 17. The rearward belt drive comprises a drive band 32 extending around a drive pulley 33 mounted on column 31a and an outer idler pulley 33a supported adjacent the free end of member 31. Drive pulley 33 has a vertical drive shaft 34 connected thereto and mounted adjacent its upper end in a bearing housing (not shown) on column 31 and, adjacent its lower end in a bearing housing 35 on the base 12. The drive shaft 34 extends through the base and a wheel 36 is secured to the lower end of the drive shaft 34. As shown in Figure 7a an endless belt 60 extends around wheels 30 and 36, an electric motor driven pulley 61 and an idler pulley 62.The belt is arranged so that opposite sides of the belt engage wheels 30 and 36 so that the wheels are driven in opposite directions by the belt. The belts are thus driven with the inner runs 25a,32a of the belts moving away from the centreline 16.

As best seen in Figure 3 of the drawings, the adjacement inner runs 25a, 32a of the forward and rearward belt drives lie parallel to one another and are normally spaced apart from one another by a small gap. A multiplicity of belt oscillators in the form of rotary cams is indicated generally at 40. The cams are spaced apart along the inner belt run 25a between the drive pulley 26 and idler pulley 26a.

Each cam comprise a drum 41 having a rounded "diamond" shape periphery 42 providing two apices 43 at diametrically spaced locations on either side of the drums. Each drum has dependent drive shaft 44 mounted in a bearing housing 45 mounted in the cross member 15. Toothed pulleys 46 are mounted on the respect shafts 44 and an additional toothed pulley 47 is mounted on drive shaft 27 below cross-member 15.

Each adjacent pair of pulleys 46 is connected by toothed drive belts 48 to cause the drums 40 to rotate in precise synchronism and the pulley 46 nearest the frame member 10 is connected by toothed drive belt 49 to a toothed pulley 47 mounted on drive shaft 27 to cause the drums to rotate with the operation of the belt drive 25.

As best seen in Figure 3 of the drawings, the drums 40 are spaced along an axis 51 which is offset from an axis connecting drive pulley 26 and idler pulley 26a towards the inner run 25a of belt drive 17. The apices or lobes 43 on the drums sweep in synchronism through paths indicated in dotted outline and displace the inner run 25a of the belt 25 towards and momentarily into engagement with the adjacent inner run 32a of belt drive 20. A momentary nip is thereby created between the belts. Arcuate spring members 52 are supported on counter-lever mountings 53 on the inner side of belt drive 20 to bear against the inner run 32a of the belt opposite the gaps between the rotary cams 40 to support the inner run of the belt 32a between the locations where the inner run 25a of belt 25 bears against the belt.

Preferably the belts 25 and 32 are formed from an elastic medium but this is not essential provided they have the requisite flexibility to permit the belts to be deflected as indicated.

In use, when a sheet to be supplied to the ironer or other laundry equipment is suspended in front of the spreading device, the edge portions of the sheet are allowed to engage between the endles belts. The inner runs of the belts draw the edge portions of the sheet away from the centreline 16 to spread the sheet apart in front of the laundry apparatus ready to be fed into the apparatus.

In the arrangement described above, the belts are closed for approximately to 10% of their operating time and this causes the sheet to be smoothly spread by the belts. The inner runs of the belt may be arranged close and open instantaneously at a rate of 900 - 1000 times per minute.

It will be understood that the rate of oscillation of the rotary cams can be varied with respect of the speed of the belt drives by adjusting the gearing between the drives. In addition, the rotary cams may be provided with an independent drive motor which can then be independently controlled to provide the required frequency closure. Further rotary cams 40 may also be provided for oscillating the inner runs 32a of belts 32 with the cams for belt run 32a staggered between those of belt run 25a.

With this arrangement the spacing between the belt runs can be increased. The cams acting on the inner and outer belt runs would need to be synchronised to displace the adjacent inner runs of the belts simultaneously and to that end the belt 60 and wheels engaged by the belt for driving shafts 27 and 34 would be toothed to co-ordinate the front and rear conveyor drives.

Claims (8)

1. A device for spreading a sheet or the like which is fed with its centre generally on a centreline of the device, the device comprising two pairs of endless belts positioned symmetrically with respect to the centreline, one pair on each side of the centreline, each belt having an inner run which faces the inner run of the other belt of the pair, driving means coupled to said belts for driving the belts in contra-rotating fashion with the inner runs thereof moving away from said centreline and means engageable with the inner runs of one belt of each pair at a multiplicity of spaced locations for periodically closing said inner runs in synchronism together to "nip" side portions of the sheet at spaced locations between the inner runs of the belt and thereby spread the sheet between the inner runs of the endless belt.

2. A device as claimed in Claim 1, wherein the belt displacing means is arranged to close said inner runs together for approximately 10 to 15% of the operating time leaving the belts apart for the remaining time.

3. A device as claimed in Claim 1 or Claim 2, wherein the belt displacing means act on one or both inner run(s) of each pair of belts at a multiplicity of locations along said run or runs.

4. A device as claimed in Claim 3, wherein the belt displacing means comprise a multiplicity of rotary cams disposed at spaced locations along one inner run of each pair of belts, the cams being driving by the belt drive means to deflect the belts at each of said locations towards the adjacent inner runs of each pair of belts.

5. A device as claimed in Claim 4, wherein the rotary cams comprise a plurality of diamond shaped drums mounted between the inner and outer bands of said one band of each pair, each drum being dimensioned and positioned so that the inner run of the band is deflected towards the inner run of the adjacent band each time the elongate direction of the drum extends transversely to the inner run.

6. A device as claimed in any of the preceding claims, wherein a single drive motor is provided for each pair of belts.

7. A device as claimed in any of the preceding claims and in the case where rotary cams are spaced along one inner run only of each pair of belts, wherein resilient support elements are provided for the other inner run staggered with respect to the rotary cams.

8. A sheet spreading device substantially as described with reference to and as illustrated in the accompanying drawings.