WO1992002055A1

WO1992002055A1 - Enveloping apparatus

Info

Publication number: WO1992002055A1
Application number: PCT/GB1991/001195
Authority: WO
Inventors: Robert Timothy Hopwood
Original assignee: Tbs Engineering Limited
Priority date: 1990-07-23
Filing date: 1991-07-18
Publication date: 1992-02-06
Also published as: AU8196291A

Abstract

This invention relates to methods and apparatus for forming an envelope of material for a battery plate and to methods and apparatus for inserting the battery plate. Enveloping apparatus (12), for locating a battery plate (13) in an envelope of material (14), has a pair of feed rollers (15); a pair of cut and groove rollers (17), a pair of fold rollers (19); and adjustable stop (20). A length of material is caused to bend into the fold rollers (19) as its leading edge engages the stop (20). Means, including a recriprocating delivery table (27) are described for delivering battery plates (13) to the fold roller (19).

Description

Enveloping Apparatus

This invention relates to methods and apparatus for forming an envelope of material for a battery plate and to methods and apparatus for inserting the battery plate. Traditionally groups for batteries were formed by alternately stacking plates and separators. In recent years the individual separators have been replaced by envelopes of microporous material which are formed around the battery plates. A group is then formed by stacking, alternately, unenveloped and enveloped plates. In order to attempt high speed fabrication proposals have been made to fold the material around the bottom edge of a battery plate travelling generally transversely to the sheet of material. The fold is either formed around the bottom edge or the bottom edge is intended to strike a preformed foldline to initiate folding. In practice either operation requires an accuracy of feeding and timing which is difficult to achieve and, particularly if high speed operation is attempted, misfitting or skew envelopes often result. From one aspect the invention consists in apparatus for forming an envelope of material for a battery plate comprising,_, a pair of folding rollers arranged to define a nip, means for delivering a precut length of material, having a foldline formed across its width, past the nip and against a stop such that the material folds along the foldline into the nip and means for sealing the edges of the

SUBSTITUTE SHEET material to form an envelope.

Preferably the delivery means and the stop are mutually disposed relative to the length of material, such that the delivery means continues to drive the material against the stop after the material engages the stop. The position of the stop may be adjustable in the direction of travel of the material so that the apparatus can accommodate different lengths of material, as, for the foldline to fold into the nip, the stop should generally be approximately the same distance from the centre line of the nip, when measured along the direction of travel, as the distance between the foldline and the leading edge of the material. Chute means may be provided for defining the path of travel of the material. These chute means may be inclined towards the nip, when viewed back along the path of travel, so that it can initiate folding of the material.

The delivery means may be a pair of rollers upstream of the nip, in which case one of the delivery rollers may be the upstream roller of the folding rollers. The apparatus may further comprise means for supplying a continuous length of material, means for forming a foldline in the material and means for cutting lengths of the material such that the foldline extends across the material in the middle of the cut length. The sealing means may crimp the edges or they may be ultrasonically welded. Other suitable sealing methods and apparatus may also be used.

The apparatus may further comprise means for delivering

SUBSTITUTESHEET a battery plate bottom first into the nip such that the envelope is formed around the plate. In this case the plate delivery means may include a table and means for reciprocating the table towards and away from the nip. Preferably the plate delivering means approaches zero velocity as the plate is delivered into the nip. It can for example be driven by a crank, or other simple harmonic motion device, which reaches its most extended position at the moment of plate delivery. It is further preferred that the plate delivering means match the delivery speed of the battery plate to the rate at which the envelope is taken through the nip so that there is little or no relative velocity between the plate and the folding envelope at the point of plate delivery. It has further been established that the material is first gripped at a point laterally off-set from the line passing through the axes of the nip rollers which, for the purposes of the specification, we will call the "nip point". In a typical embodiment this nip point may be offset by 5 to 10 mm from the aforementioned line.

Preferably the plate delivery means are arranged to deliver the plate to the nip point at or just after the arrival of the fold at the nip point. It is the relative velocity of the plate and folding material at the nip point which is particularly significant.

The table may have a first level for receiving a plate and a second level for supporting the plate during delivery and means for wiping the plate from the first level onto the

SUBSTITUTE SHEET second level during movement of the table away from the nip. In this case the second level may be formed or dimensioned to determine the delivery position of the plate and the table may be adjustable such that the dimensions of the second level may be adjusted to receive different sizes of plate.

From another aspect the invention consists in apparatus for placing a battery plate in an envelope comprising means for folding a length of material, for example into a nip of cooperating rollers, and means for delivery the plate into the folding material.

The novel and inventive approach of inserting the battery plate into the envelope as it is formed greatly reduces the possibility of misfeeding, skew envelopes and incorrect sealing. The features of the plate delivery means set out above are also incorporated into this aspect of the invention and those set out below.

Thus with the apparatus describe above, in contrast to the prior art, the envelope will be formed whether or not the battery plate is fed and therefore its quality of production is not dependent on a complex feeding relationship between the plate and the material.

The invention also includes a method for forming an envelope of material for a battery plate comprising delivering a pre-cut length of material, having a foldline formed across its width, past a nip defined by a pair of co¬ operating rollers and against a stop such that the material folds along the foldline into the nip and sealing the edges

SUBSTITUTE SHEET of the material to form an envelope.

The invention still further includes a method of placing a battery plate into an envelope comprising folding a length of material (for example into a nip of cooperating rollers) and delivering the plate into the folding material.

Preferably the plate is decelerated such that it is delivered into the folding material at or approaching zero velocity.

The invention additionally includes an envelope and/or battery plate/envelope assembly formed by the apparatus or methods set out above.

Although the invention has been defined above it is to be understood that it includes any inventive combination of the features set out above or in the following description. The invention may be performed in various ways and a specific embodiment will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of an enveloping apparatus;

Figure 2 is an end view on the arrow A of Figure 1;

Figure 3 is an end view of the envelope unit of the apparatus of Figure 1 on the arrow B;

Figures 4a to f illustrate, schematically, the operational cycle of the apparatus of Figure 1.

Figure 5 is a diagrammatic representation of the jrank, the delivery table and the nip rollers of the enveloping apparatus of Figure 1.

SUBSTITUTESHEET In Figure 1 a battery plate handling apparatus, which is generally indicated at 10, comprises apparatus for peeling single battery plates from a horizontal row or stack, which is generally indicated at 11 and enveloping apparatus generally indicated at 12. The battery plate peeling apparatus is the subject of British Patent Application No. 9016133.2 and the International Application based thereon and those disclosures are incorporated herein by reference. The purpose of the enveloping apparatus 12 is to locate a battery plate 13 in an envelope of microporous material 14 for the reasons set out above. The apparatus 12 has a pair of feed rollers 15, which take the sheet of material 16 from a supply; a pair of cut and groove rollers 17; a further pair of feed rollers indicated at 18; a pair of fold rollers indicated at 19 (the upper fold roller forming one of the feed rollers 18); and an adjustable stop 20.

As can best be seen in Figures 4a to f the material 16 is fed downwardly, by the first feed rollers 15 to the cut and groove rollers 17 in which roller 17a acts as an anvil and roller 17b has a blunt edge 21 for forming a foldline and a knife edge 22 for cutting the material into lengths. Thus as can be seen in Figure 4a the knife edge 22 first cuts the lead edge of an envelope forming portion 23 of the material 16, the blunt edge then forms a foldline across the width of that portion and the knife edge 22 then cuts the portion to length (see the lower half of Figure 4a) . Before this second cut occurs the portion 23 has been gripped by the feed rollers 18 which feed the portion 23 past the nip 24 defined by the fold rollers 19 until its leading edge engages the adjustable stop 20. These rollers then continue to drive the portion 23 against the stop 20 with the result that it folds inwardly towards the nip 24 and is driven into the fold rollers 19 so that it is formed into a folded piece of material. Simultaneously its edges are sealed by either crimp wheels or an ultrasonic soldering device (not shown) . Thus it will be seen that the apparatus forms the envelopes whether or not there is a battery plate 13 present. Whilst there is no particular benefit in merely forming empty envelopes, this mode of operation means that the quality and accuracy of the envelopes formed by the apparatus is not dependent on the quality and accuracy of the feeding of the battery plates, as is the case with the prior art arrangements. This means that consistently good envelopes can be formed by the apparatus at high speed.

It also enables quite a different approach to be made with the positioning of the battery plates. As the plates do not take any part in the forming envelope they can simply be placed into the forming envelope at a very low speed, with the result that the battery plates are unlikely to inflict any distorting forces on the envelope being formed.

As can be seen from Figure 2 individual battery plates 13 are conveyed along a lateral conveyor 25 where they are deposited on an upper level 26 of a delivery table 27 (see Figure 4c) . As will be explained in detail below this table 27 is reciprocated towards and away from the nip 24 and during the return journey the battery plate 13 is wiped off the upper level 26 by a bar 28 (see Figure 4d) so that it is transferred, progressively, onto a lower level 29 on the delivery table 27. It is then precisely located in the delivery position shown in Figure 4a and is delivered into the nip 24, as shown in Figures 4b and c so that the fold rollers 19 complete the formation of the envelope around the battery plate 13.

The table 27 is reciprocated by means of a crank 30 and a motor 31. As is well known the crank will perform simple harmonic motion and the apparatus is arranged so that the table 27 is approaching zero velocity as the leading edge of the plate 13 approaches the nip 24. Similarly the final wiping of the plate 13 onto the lower level 29 can take place at low velocity so that both the positioning and the delivery of the battery plate provide delicate and precise handling, but the rest of the delivery operation is carried out at high speeds.

It will be appreciated that the battery plates 13 are fed bottom edge first into the nip 24, and those skilled in the art will be aware that such plates are generally provided with feet. Accordingly, as can be seen in Figure 3, the fold rollers 19 are provided with grooves 32.

The position of the stop 20 and the size of the lower level 29 are adjustable to allow the enveloper to handle different sized battery plates. The length of the portion 23 can be varied by altering the feed speed or the speed of rotation of rollers 17. As has been mentioned above it is particularly advantageous to match the delivery speed of the battery plate to the rate at which the envelope is taken through the nip. This aspect of the machine will now be described with reference to Figure 5.

The crank 30 comprises first and second elements 35 and 36 having respective lengths r and 1 and it will be appreciated, from Figure 5, that the velocity V of the delivery table 27 is a direct function of the angle θ in accordance with the formula V = rw Sin θ + sin 26 where N = 1/r. 2N

The magnitude of θ at the point at which the plate is delivered to the nip point 37 is effectively determined by the distance d between the connection of the crank to the delivery table and the leading edge 39 of the delivery table 27. The longer that distance is, the earlier in the crank cycle the leading edge 39 reaches the nip point 28 and hence the greater the value of θ and the velocity of the delivery plate 27. Thus by adjusting the distance d one can adjust the rate at which the plate is delivered to the nip point 38.

This adjustment can be easily obtained by providing a set of leading edge support plates such as is illustrated on the front of the delivery plate 27 in Figure 4d. By using plates of different lengths, in the direction of delivery, one can readily obtain different delivery velocitier at the nip point. It will generally also be necessary to replace the upper level 26, so that the lower level of the delivery table is correctly dimensioned to hold a particular size of plate 13 in the required relationship with the leading edge of the delivery table 27.

In the Applicant's preferred embodiment the velocity of the material through the nip point is very much a function of the size of battery plate to be enveloped and so it is simple to provide suitable sets of leading edge support plates and upper levels 26 to match the different sizes of battery plates 13 to be processed. However in other arrangements a greater degree of adjustment may be desirable in which case both the leading edge support plate and the upper level 26 may be slidably mounted on the delivery table 27.

Claims

1. A method of placing a battery plate into an envelope comprising folding a length of material and delivering the plate into the folding material.

2. A method for forming an envelope of material for a battery plate comprising delivering a precut length of material, having a fold line formed across its width passed a nip defined by a pair of cooperating rollers and against a stop such that the material folds along the fold line into the nip and sealing the edges of the material to form an envelope.

3. A method as claimed in Claim 1 or Claim 2, further comprising decelerating the plate such that it is delivered into the folding material at or approaching zero velocity.

4. A method as claimed in any one of Claims 1 to 3 wherein the delivery speed of the battery plate matches the rate at which the envelope is taken through the nip so that there is little or no relative velocity between the plate and the folding envelope at the point of delivery.

5. A method as claimed in any one of Claims 1 to 4 wherein the plates are delivered to the "nip point" at or just after the arrival of the fold at the nip point.

6. Apparatus for placing a battery plate into an envelope including means for folding a length of material and means for deliverying the plate into the folding material.

7. Apparatus for forming an envelope of material for a battery plate comprising a pair of folding rollers arranged to define a nip means for delivering a precut length of material, having a fold line formed across its width, passed the nip and against a stop such that the material folds along the fold line into the nip and means for sealing the edges of the material to form an envelope.

8. Apparatus as claimed in Claim 7 , wherein the delivery means and the stop are mutually disposed relative to the length of material such that the delivery means continues to drive the material against the stop after the material engages the stop.

9. Apparatus as claimed in Claim 7 or Claim 8, wherein the position of the stop is adjustable in the direc¬ tion of travel of the material.

10. Apparatus as claimed in any one of Claims 7 to 9, further comprising chute means for defining the path of travel of the material.

11. Apparatus as claimed in Claim 10, wherein the chute means are inclined towards the nip when viewed back along the path of travel.

12. Apparatus as claimed in any one of Claims 7 to 11, wherein the delivery means are a pair of rollers upstream of the nip.

13. Apparatus as claimed in Claim 12, wherein one of the delivery rollers is constituted by the upstream roller of the folding rollers.

14. Apparatus as claimed in any one of Claims 7 to 13, further comprising means for supplying a continuous length of material, means for forming a fold line in the material and.means for cutting lengths of the material such that the fold line extends across the material in the middle of the cut length.

15. Apparatus as claimed in any one of Claims 7 to 14, wherein the sealing means crimps the edges.

16. Apparatus as claimed in any one of the Claims 7 to

14, wherein the edges are ultrasonically welded.

17. Apparatus as claimed in any one of Claims 7 to 14, further comprising means for delivering a battery plate bottom first into the nip such that the envelope is formed around the plate.

18. Apparatus as claimed in Claim 17, wherein the plate delivery means includes a table and means for reciprocating the table towards and away from the nip.

19. Apparatus as claimed in Claim 17 or Claim 18, wherein the plate delivery means approaches zero velocity as the plate is delivered into the nip.

20. Apparatus as claimed in any one of Claims 17 to 19, wherein the plate delivery means is driven by a crank which reaches its most extended position at. the movement of plate delivery.

21. Apparatus as claimed in Claim 18, wherein the table has a first level for receiving a plate and a second level for supporting the plate during delivery and means for wiping the plate from the first level on to the second level during the movement of the table away from the nip.

22. Apparatus as claimed in Claim 21, wherein the second level is dimensioned to determine the delivery position of the plate.

23. Apparatus as claimed in Claim 22, wherein the table is adjustable such that the dimensions of the second level can be adjusted to receive different sizes of plate.

24. Apparatus for placing a battery plate in an envelope comprising means for folding a length of material into a nip of cooperating rollers and, means for delivering the plate into the folding material.

25. Apparatus as claimed in Claim 17 or any one of Claims 18 to 23 as dependent on Claims 18 or Claim 24 wherein the plate delivering means matches the delivery speed of the battery plate to the rate at which the envelope is taken through the nip.

26. Apparatus as claimed in any one of Claims 7 to 25, wherein nip means have a "nip point" lateral offset from a line passing through the axes of the nip rollers.

27. Apparatus as claimed in Claim 26 wherein the "nip point" is offset from the line by between 5 mm and 10 mm.

28. Apparatus as claimed in Claim 26 as dependent on Claim 17 or any one of Claims 23 to 27 as dependent on Claim 17 or Claim 24 wherein the plate delivery means are arranged to deliver the plate to the "nip point" at or just after the arrival of the fold at the "nip point".

29. Apparatus for forming an envelope of material substantially as hereinbefore described, with reference to the accompanying drawings.

30. A method of forming an envelope substantially as hereinbefore defined, with reference to the accompanying drawings.

31. A method of placing a battery plate in an envelope substantially as hereinbefore defined, with reference to the accompanying drawings.

32. An envelope or a battery plate/envelope assembly formed by the apparatus or methods of any one of the preceding Claims.