Apparatus for feeding and spreading pieces of cloth

Disclosed herein is an apparatus and a method for receiving and straightening four edge pieces of cloth, the apparatus having a machine direction parallel with a delivery direction of the straightened cloth, the apparatus comprising; at least three charger stations, each for receiving a piece of cloth and locating a pair of adjacent fore edge corners of the cloth, a set of spreader clamps for releasably receiving the pair of adjacent fore edge corners, at least two grippers, each for conveying the pair of fore edge corners from the charger station to the set of spreader clamps, where the grippers are configured to move along at least a portion of a first path transversally to the machine direction, wherein at least one central charger station has a first waiting location for the cloth with the corners being located, the waiting location being retracted opposite the machine direction from the set of spreader clamps away from the first path.

FIELD OF THE INVENTION

The invention relates to a charging and stretching apparatus comprising multiple charger stations for receiving and straightening pieces of laundry, which rapidly and accurately transfer and spread sheets of laundry and place them onto a conveyor for subsequent processing by ironing machines, folding machines or the like.

BACKGROUND OF THE INVENTION

After laundry articles such as bed sheets, table linens, blankets, or the like are washed in a laundry facility, they are typically fed into a flatwork ironer and automatic folded into a neat package for use in hotels, hospitals, or the like. In order to obtain a neatly folded, unwrinkled package, it is important that the sheet is presented to the ironer with no wrinkles or folds and with the leading edge straight.

Modern laundry facilities use an automatic spread feeder apparatus to allow more rapid and accurate feeding of the sheets into the ironer. Various spread feeder apparatus' are designed to accommodate multiple operators at different charger stations. This increases the speed at which the sheets can be fed to the spreader clamps at the spreader station and improves the overall output of the spread feeder apparatus. Such apparatus is disclosed in the U.S. Pat. No. 5,440,810.

One disadvantage of many spread feeder apparatus' are, that they do not take fully advantage of the capacity of the spreader station due to the time required for transporting the sheets of laundry from the charger stations to the spreader station.

It is therefore desirable to provide an apparatus which improve the use of the capacity of the spreader station and thereby operates even more rapidly than other spread feeder apparatus'.

SUMMARY OF THE INVENTION

Disclosed herein is an apparatus for receiving and straightening four edge pieces of cloth, the apparatus having a machine direction parallel with a delivery direction of the straightened cloth, the apparatus comprising; at least three charger stations, each for receiving a piece of cloth and locating a pair of adjacent fore edge corners of the cloth, a set of spreader clamps for releasably receiving the pair of adjacent fore edge corners, at least two grippers, each for conveying a respective piece of cloth from the charger station to the set of spreader clamps, by gripping onto the fore edge corners thereof, where the grippers are configured to move along at least a part of a first path transversally to the machine direction, wherein at least one central charger station has a first waiting location for the cloth with the corners being located, the waiting location being retracted opposite the machine direction from the set of spreader clamps away from the first path.

This arrangement allow for a more efficient use of the set of spreader clamps capacity, as the cloth can be held in the first waiting location until a gripper takes over the cloth so that another cloth can be conveyed by the gripper along the first path from an end charger station, i.e. a charger station at the end of the first path, past the awaiting cloth in the central charger station.

By an “central” charger station is meant a charger station placed in-between the two end charger stations.

Each gripper may have two clamps, wherein each clamp may grip a respective one of the two fore edge corners of the cloth.

The set of spreader clamps may be waiting in a receive position, approximately in the centre of the two end charger stations when being in its non-operating state, i.e. when it is not spreading a cloth.

The apparatus may comprise an uneven number of charger stations, such as three or five. Whereas an apparatus with three charger stations has one central charger station which may be placed in line, i.e. parallel to the machine direction, with the set of spreader clamps in their receive position. Having three charger stations and two grippers, a first gripper may collect cloths' from a left hand side end charger station and the central charger station and a second gripper may collect cloths' from a right hand side end charger station and the central charger station.

Having five charger stations and two grippers, the first gripper may collect cloths' from a left hand side end charger station and two central charger stations, i.e. a left hand side central charger stations and a mid central charger station, the second gripper may collect cloths' from a right hand side end charger station and two central charger stations, i.e. a right hand side central charger stations and the mid central charger station. Wherein the mid central charger station is placed in line, i.e. parallel to the machine direction, with the set of spreader clamps in their receive position.

The apparatus may comprise an even number of charger stations, such as four or six. Whereas an apparatus with four charger stations has two central charger stations which may be placed on each side of the set of spreader clamps in their receive position. Having four charger stations and two grippers, the first gripper may collect cloths' from a left hand side end charger station and a left hand side central charger station and the second gripper may collect cloths' from a right hand side end charger station and a right hand side central charger station.

An apparatus with six charger stations has four central charger stations wherein two central charger stations may be placed on each side of the set of spreader clamps in their receive position. Having six charger stations and two grippers, the first gripper may collect cloths' from a left hand side end charger station and two left hand side central charger stations and the second gripper may collect cloths' from a right hand side end charger station and two right hand side central charger stations.

A conveyer belt may be configured to run below the grippers along the first path, for guiding a trailing edge of the cloth. The conveyer belt may run parallel with the first path. The conveyer belt may comprise a first and a second conveyer belt.

It may be defined that the starting point for processing the cloth is to feed a fore edge of the cloth to the charger stations. The charger stations then locates a pair of trailing edge corners of the cloth which in the further processing, when spreading the cloth, becomes the pair of fore edge corners. The term “fore edge corners” is thereby used to identify the corners handled by the apparatus, i.e. when spreading a piece of cloth with the set of spreader clamps, and not necessarily the corners of the edge feed to the apparatus which may be the same or a different edge of the cloth.

In one or more embodiments the first conveyer belt and the second conveyer belt extends from the end charger station to just before a receiving position of the set of spreader clamps, so a second path of movement of the grippers towards the set of spreader clamps and parallel with the machine direction is free of the first and second conveyer belt.

The first and second conveyer belt may guide a trailing end of the cloth conveyed by the grippers from the end charger stations towards the set of spreader clamps. The first and second conveyer belt may run with the same speed as the grippers and the first and second conveyer belt may only run if guiding a trailing edge of the cloth i.e. when the grippers conveys a cloth towards the spreader clamps and is in movement. This arrangement allow for a faster delivery of the cloth along the first path.

In one or more embodiments a third conveyer belt runs between the first and second conveyer belt along the second path, the third conveyer belt optionally running in a level below the first and second conveyer belt. The width of the third conveyer belt may at least be the same as the distance between the first or second conveyer belt or wider. The first and second conveyer belt may deliver the trailing end of the cloth to the third conveyer. The trailing end of a cloth from a central charger station in line with the set of spreader clamps may be delivered to the third conveyer belt directly from the first waiting location. This arrangement allow for a faster delivery of the cloth along the second path.

In one or more embodiments the first waiting location comprises a buffer station, preferably a conveyer or a tray.

The buffer station keeps the trailing end of the cloth away from the first, second or third conveyer belt, i.e. above the first, second or third conveyer belt, until one of the grippers takes over the pair of fore edge corners from one of the charger stations. It is thereby avoided that the trailing end moves away from the respective charger station before the grippers take over the fore edge corners from one of the charger stations and starts transporting the cloth towards the spreader clamp. It is thereby further avoided that two cloths is tangled together when passing each other.

In one or more embodiments the tray is downwardly pivotable towards the first path. The buffer station may be pivoted when one of the two grippers take over the pair of fore edge corners from the charger station. The buffer station may thereby deliver the trailing end of the cloth to either the first or second conveyer belt along the first path or the third conveyer belt along the second path.

In one or more embodiments the apparatus comprises an arm configured for moving the grippers from the first path towards the charger stations and back, along a third path. The third path may be parallel with the machine direction. The arm may be a telescoping arm or a rail whereon the gripper may run. The arm may be configured for moving the grippers so that they can collect the pair of fore edge corners from charger stations placed with at least two different distances from the first path. There may be a difference in the distance of 10 to 50 cm or more preferable between 20 to 30 cm. The arms may also be configured for moving the grippers along the second path.

In one or more embodiments the grippers have a waiting position along the first path.

This arrangement allow for an even more efficient use of the set of spreader clamps capacity. This as the cloth conveyed by the first gripper may await the delivery of another cloth conveyed by the second gripper closer to the receive position of the set of spreader clamps.

In one or more embodiments the apparatus includes a central charger station and a charger station at a respective end of the first path, wherein one or both of the end charger stations have a respective one of the first waiting location being retracted opposite the machine direction from the set of spreader clamps away from the first path.

This arrangement allow for an even more efficient use of the set of spreader clamps capacity. This as both the end and central charger stations may comprise a buffer station which together with at least two waiting locations along the first path allow for at least five cloths in transit towards the set of spreader clamps at the same time, i.e. one cloth per charger station plus one cloth per gripper.

Each charger station may comprise three motors. One motor for running a feed conveyer belt an two motors for running each of two sets of locations rolls, whereas each set of location rolls locate one fore edge corner. Hereby may the feed conveyer belt be controlled separately from the two sets of location rolls, so that the cloth may be waiting close to the two sets of positioning rolls. This may allow for an even more efficient use of the set of spreader clamps capacity as the cloth may be advanced even faster towards the set of spreader clamps.

Furthermore is disclosed a method of conveying four edge pieces of cloth from at least three charger stations to a set of spreader clamps by means of at least two grippers, each for conveying a respective piece of cloth, using an apparatus for receiving and straightening the cloth having a machine direction parallel with a delivery direction of the straightened cloth, the method comprising: locating a pair of fore edge corners of a first piece of cloth by means of one of the charger stations, collecting the located pair of fore edge corners of the first piece of cloth from the one charger station by one of the grippers, and conveying the first piece of cloth from the charger station to the set of spreader clamps by the one gripper along at least a part of a first path transversally to the machine direction, wherein at least one central charger station is configured to define a cloth waiting position which is retracted from the first path in a direction opposite the machine direction, and the method further comprises the step of holding a second piece of cloth, with the pair of fore edge corners thereof being located, in the first waiting location of the central charger station before the second piece of cloth is collected by the grippers and while the first piece of cloth is conveyed to the set of spreader clamps.

The charger station for locating a pair of fore edge corners of the first piece of cloth may be one of the end charger stations. If the apparatus comprises five charger stations or more the charger station for locating a pair of fore edge corners of the first piece of cloth may be one of the end charger stations or one of the central charger stations.

In one or more embodiments the aforementioned method is performed with the apparatus described above.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 and 2schematically show a top view of an apparatus1according to the invention for receiving and straightening a four edge piece of cloth (not shown) having a machine direction2parallel with a delivery direction of the straightened cloth. The apparatus1includes a housing3(see alsoFIG. 3) having a front wall4, an end wall5, as well as two opposite longitudinal sides6extending parallel with the machine direction2. The housing is partially divided into two sections by two partition walls7each extending from one of the end walls6towards the center of the apparatus1and perpendicular to the machine direction2, whereas the two partition walls7define an opening between the two sections approximately in the center of the apparatus1.

The apparatus1comprises three charger stations10′,10″,10′″, each for receiving a mid-section of a piece of cloth, if the cloth is rectangular preferably a mid section of one of the longer edges, and for locating a pair of adjacent trailing edge corners of the cloth which from then becomes the fore edge corners. All three charger stations10′,10″,10′″ are in the presently illustrated embodiment retracted parallel with the machine direction2from a set of spreader clamps20, i.e. retracted from the first path40in the direction opposite the machine direction2, and defining a first waiting location11comprising a buffer station12in shape of a tray13.

The apparatus further comprises a first and a second gripper30′,30″ for conveying the pair of fore edge corners from the charger stations10′,10″,10′″ to the set of spreader clamps20.

The first and second gripper30′,30″ is configured to move along a respective portion of a first path40(seeFIG. 2) transversally to the machine direction2, between the centre of the apparatus1and one of the end charger stations10′,10′″. This may be by means of a rail R running parallel with the first path40and carrying a gripper support G. A first conveyer belt42′ and a second conveyer belt42″ extends from each end/outermost charger stations10′,10′″ towards the center of the apparatus1to just before the set of spreader clamps20in their receive position R, so a second path50of movement of the grippers30′,30″ (seeFIG. 2) from the first path40towards the set of spreader clamps20and parallel with the machine direction2is free of the first and second conveyer belt. The second path50goes through the before mentioned opening defined by the partition walls7. A third conveyer belt51runs between and in a level below the first and second conveyer belt42′,42″ along the second path50. The first path40preferably extends symmetrically away from the second path50.

An arm31which is a part of the gripper support G, is configured for moving the grippers from the first path40towards the charger stations10′,10″,10′″ and back, i.e. along a respective third path60, preferably parallel with the second path50, as well as along the second path50.

Each gripper has in the presently illustrated embodiment two clamps130, each clamp130having opposite closeable arms defining a gap between which a respective one of the fore edge corners is gripped.

The set of spreader clamps20is configured for releasably receiving the pair of adjacent fore edge corners from the two grippers30′,30″ in turn and then moving in opposite directions from each other away from the centre of the apparatus and transversally to the machine direction2. Hereby is the cloth straightened and delivered to a fourth conveyer belt70for conveying the straightened cloth to a flatwork ironer, an automatic folder or the like (not shown).

Turning now toFIGS. 3-7the conveying operation performed by the grippers30′,30″ from the charger stations10′,10″,10′″ to the set of spreader clamps20will be described by discussing the progressive figures fromFIG. 3toFIG. 7together with theFIGS. 1 and 2.

As can be seen inFIG. 3a cloth80is feed to one of the charger stations10′,10″,10′″. The charger station10′,10″,10′″ then locates the fore edge corners FE of the cloth80and holds the cloth in the corners FE in a first waiting location above a tray13as shown onFIG. 4. Providing such a waiting location off-set from the first path40(seeFIG. 1) allows for the grippers30′,30″ to move the cloth from the end charger stations10′,10′″ to a transfer position T (seeFIG. 7) while the cloth is ready to be picked up from the central station(s) by a gripper30′,30″ in a subsequent step.

As shown inFIG. 5one of the two grippers30′,30″ moves towards one of the three charger stations10′,10″,10′″ along one of the third paths60(seeFIG. 2) into its collect position C and the tray13is downwardly pivoted. Hereby is the trailing edge of the cloth80delivered to the first or second conveyer belt42′,42″ if taken from one of the end charger stations10′,10′″ (seeFIG. 1) or to the third conveyer belt51if taken from the central charger station10″ (seeFIG. 1).

The gripper30′,30″ is then moved back along the third path60(see alsoFIG. 2) to the first path40as shown inFIG. 6. If the cloth80is taken from the central charger station10″ (seeFIG. 1) the gripper30′,30″ may preferably continue along the second path50(see alsoFIG. 2) towards the set of spreader clamps20to the transfer position T. If the cloth is taken from one of the end charger stations10′,10′″ (seeFIG. 1) the gripper30′,30″ may either move along the first path40and continue directly along the second path50to the transfer position T, or the gripper30′,30″ may stop at a waiting position41along the first path40(seeFIG. 2) and wait for its turn to approach the set of spreader clamps20, i.e. until the other gripper has moved away from the second path50and towards the opposite outermost/end charger station10′,10′″ along the first path40or towards the central charger station10″ along the third path60.

The first conveyer belt42′ runs in the direction towards the center of the apparatus when the first gripper30′ approaches the set of spreader clamps20with a cloth80from the end charger station10′ along the first path40(seeFIG. 2).

The second conveyer belt42″ runs in the direction towards the center of the apparatus when the second gripper30″ approach the set of spreader clamps20with a cloth80from the end charger station10′″ along the first path40(seeFIG. 2).

The third conveyer belt51runs in the machine direction2when the first or second gripper30′,30″ has collected a cloth80from the central charger station10″ and when one of the two grippers30′,30″ approach the set of spreader clamps20with a cloth80from one of the end charger stations10′,10′″ along the second path50(see alsoFIG. 2).

Finally as shown inFIG. 7the gripper30′,30″ moves toward the set of spreader clamps20along the second path50into the transfer position T and the cloth80is transferred from the gripper30′,30″ to the set of spreader clamps20so that the set of spreader clamps20can spread out the cloth and deliver it to the fourth conveyer belt70. The movement of the spreader clamps and the delivery of the cloth to the fourth conveyer belt are discussed in WO 2012/163356.

As shown onFIG. 8each charger station10′,10″,10′″ may in one embodiment comprise an upper and lower feed conveyer belt90and91, two set of location rolls92′,92″ and93′,93″ and three motors (not shown), whereas the upper and lower feed conveyer belt is controlled by one motor and each set of location rolls are controlled by their own motor, i.e. each set of location rolls are controlled by a separate motor.

The rolls of each set of locations rolls e.g.92′ and92″ are spaced apart, creating a gap (not shown) between the rolls92′ and92″, when they are not in engagement with a cloth.

When feeding a cloth (not shown) to the charger station10′,10″,10′″ a first sensor94is affected and the upper and lower feed conveyer belt90and91start running. The cloth is advanced in-between the upper and lower feed conveyer belt until the cloth affects a second sensor95.

If the set of locations rolls92′,92″ and93′,93″ already is in engagement with the fore edge corners of a previously loaded cloth which is at the aforementioned first waiting location11(seeFIG. 1), the upper and lower feed conveyer belt90and91stops and holds the cloth waiting until one of the grippers30′,30″ (seeFIG. 1) have taken the previously loaded cloth from the two sets of location rolls.

If the set of locations rolls92′,92″ and93′,93″ are free, i.e. the two rolls in each set of location rolls is spaced apart, the cloth continues past the second sensor95and the two sets of location rolls92′,92″ and93′,93″ starts rotating at a high speed. When a third and or fourth sensor96and97is affected by the cloth the two rolls in each set of location rolls92′,92″ and93′,93″ are urged towards each other independently and the cloth is advanced by the rolls of the two sets of location rolls.

When the entire cloth has passed the second sensor95, the two sets of location rolls92′,92″ and93′,93″ slows down to a medium speed, and when the trailing edge corners of the cloth which from then becomes the fore edge corners have passed the third sensor96, the two sets of location rolls92′,92″ and93′,93″ slow down to a slow speed.

Finally when the fore edge corners have passed the fourth sensor97, the two sets of location rolls92′,92″ and93′,93″ slow down and stop, holding the fore edge corners of the cloth ready for the gripper30′,30″ (seeFIG. 1) to take over the corners.

The first, second, third and/or fourth sensor94,95,96,97may be photocells which are affected by the cloth as the sensors are darkened or covered by the cloth.

The principles discussed with reference toFIG. 8may find use independently of the apparatus specifically claimed in the claims.