GB2394162A

GB2394162A - Method of manufacturing a casing end seal

Info

Publication number: GB2394162A
Application number: GB0220507A
Authority: GB
Inventors: Robert Nicholl Mackellar David; Allan James Hanlon
Original assignee: Devro Inc
Current assignee: Devro Inc
Priority date: 2002-09-04
Filing date: 2002-09-04
Publication date: 2004-04-21
Also published as: GB0220507D0

Abstract

A seal in a tubular casing is formed by twisting the casing, folding the end of the casing back over the seal to give a double thickness portion and inserting the sealed end and double thickness portion inside the casing.

Description

2394 1 62

METHOD OF MANUFACTURING A CASING END SEAL

The present invention relates to a method of creating a 5 seal in a tubular casing, such as a casing for food products.

The invention further relates to an apparatus for performing such a method, and to a sealed tubular casing produced by such a method.

Many food products, such as sausages and similar 1() products, are produced by extruding a malleable edible filling (such as sausage meat) into an edible tubular casing, which may be sealed. For mass production of such items, typically a piece of casing many times longer than a single item is provided, sealed at one end, filled with a filling, 15 and subsequently divided into individual food items, for example by twisting.

It is necessary that the end seal is relatively strong, since often the filling is extruded into the casing at high speeds with a substantial force; an inadequate seal may 2() result in the casing bursting, and a wasted batch of filling.

One method of generating the end seal is to heat seal the casing; however, this method requires the use of heat-sealing equipment, and the seal so generated may still fail if the heating technique is not adequately applied to the casing.

25 It is known to provide casings having a double-thickness portion at one end, formed by twisting an end region of the casing to form a seal, and then folding the free end of the casing back over the body of the casing. Such a method provides casings having a reinforced double thickness portion A) at one end which is formed entirely from the casing material

itself, without any potentially fragile seams or the like.

Methods and casings of this sort are described in our patent application W001/82709, or in DE 3141782A1 to Kubo Sekkei Yugen Kaisha.

After the seal is formed on the casings described in these documents, the end portion of the casing may be pushed at least partially into the body of the casing. This is intended to make the casing easier to handle and transport.

However, it has been identified by the present inventors l() that casings sealed in this way can have an unacceptably high I failure rate. It has been determined that this is a result of the automated filling process: slugs of sealed casing are generally supported on a mandrel while a stuffing horn is introduced into the sealed casing; the stuffing horn will be 15 used to supply filling to the casing. In most cases the filling leaves the stuffing horn at relatively high speed, and hits the double-thickness portion of the casing slug, which portion is strong enough to contain the filling.

However, in certain circumstances, the casing horn may touch 0() the edge of that part of the casing which has been pushed inside the body of the casing, and push the sealed portion outside the body of the casing slug. Either under its own weight, or due to the sealed portion catching on a part of the stuffing machine as the slug is moved, the sealed portion 05 of the casing may be bent out of line with the body of the slug, resulting in a single-thickness portion of the casing being adjacent the stuffing horn. In such a case, when filling is introduced into the casing, this hits the weaker

single thickness portion of the casing rather than the double-thickness sealed portion, resulting in a burst casing and a wasted batch of filling.

It is among the objects of the embodiments of the 5 present invention to obviate or alleviate these and other disadvantages of existing methods.

This is achieved, in part, by folding of a portion o the sealed region of the casing as it is introduced into the body of the casing, such that a stuffing horn will be less 1() likely to contact the folded region of the casing.

According to a first aspect of the present invention, there is provided a method of sealing a tubular casing, the method comprising the steps of: supporting a slug of tubular casing on a mandrel to 15 define an open free end portion and a main body portion of the slug; clamping said Open free end portion; rotating said open free end portion relative to said main body portion to create a twist in the casing; 2() folding said free end portion over said main body portion to create a sealed end and an end portion of double casing thickness near said sealed end; an inserting said sealed end and said end portion of double casing thickness inside said main body portion, such that 25 said end portion is at least partly compressed within the main body portion.

This method of sealing the casing provides a casing slug having a compressed or concertinaed end portion tucked inside

the slug. This not only keeps the end portion inside the slug and out of the way of the casing stuffing machinery, but the compressed nature of the end portion means that it does not extend as far into the slug as prior art sealed casings,

5 thus making it much less likely that the stuffing horn used to fill the casing will contact the end portion and push it out of the slug.

Further, the compressed end portion may expand steadily as the filling is injected into the slug, rather than the 1() filling being suddenly halted, so further reducing the possibility of the filling bursting the slug.

Preferably the step of clamping said open free end portion comprises the steps of: inserting a second mandrel at least partly inside said 15 free end portion; and securing said free end portion to said second mandrel.

In one embodiment of the invention, securing of the free end portion to the second mandrel may be achieved by expanding the second mandrel to exert a force against the inside of the 2() casing; alternatively, or in addition, a force may be applied against the casing externally of the mandrel.

Preferably also the folding step comprises the step of inserting a portion of said first mandrel into at least a portion of a tubular opening provided in said second mandrel.

95 Preferably the inserting step comprises pushing said sealed end and said double thickness end portion by means of a protrudable finger. Conveniently the protrudable finger is provided within the second mandrel. Alternatively, a separate

tucking assembly may be provided for performing the inserting step. The tucking assembly may include a protrudable finger or the like. Preferably the inserting step further comprises restraining the body of the slug from movement prior to 5 pushing the sealed end into the body of the slug; this may be achieved by clamping the body of the slug to the first mandrel. In certain embodiments of the invention, the sealed end may be pushed into a recess provided within the first mandrel; preferably, however, the slug is moved with respect 1() to the first mandrel to provide a gap between the sealed end and the end of the mandrel; the sealed end may then be pushed or inserted into this gap.

According to a second aspect of the present invention, there is provided an apparatus for sealing a tubular casing, 15 the apparatus comprising a first mandrel for supporting a slug of tubular casing to define an open free end portion and a main body portion of the slug; clamping means for clamping said open free end portion; rotation means for rotating said free end portion relative to said main body portion to create 0() a twist in the casing; free end folding means for folding said free end portion over said main body portion to create a sealed end and an end portion of double thickness near said sealed end; and means for permitting said sealed end and said end portion of the slug to be inserted inside said main bod 5 portion, such that said end portion is at least partly compressed within the main body portion.

Preferably the apparatus further comprises a second mandrel moveable relative to the first mandrel for insertion

(l at least partly into the open free end portion of the casing.

In one embodiment of the invention, the clamping means may comprise a plurality of expandable fingers provided on the second mandrel; expansion of these fingers while located 5 within the CaSirlq causing the mandrel to clamp the casing.

Alternatively, the clamping means comprises an external clamp for applying pressure to the casing against the second mandrel. Preferably said rotation means comprises means for 1() rotating one of said first and second mandrels relative to the other of said first and second mandrels. In a preferred embodiment of the invention, the rotation means comprises a belt-driven stepper motor operatively associated with the second mandrel. Alternative means may of course be used, for 15 example, a direct motor, a rotary motor, or the like.

Preferably the free end folding means comprises a hollow tubular portion provided on the second mandrel, and means for inserting said sealed end of said casing at least partly into said hollow tubular portion.

9() In one embodiment of the invention, the means for inserting said sealed end into the hollow tubular portion comprises an axially tnoveable inner member provided within said first mandrel, which inner member may be moved inside said second mandrel. Alternatively, said insertion means may 05 comprise means for moving said second mandrel relative to said first mandrel such that the first mandrel is received at least partly within said hollow tubular portion of said second mandrel.

Preferably the means for permitting the sealed end to be inserted into the body of the slug comprises an axially moveable inner member provided within said second mandrel.

Alternatively, the means for permitting the sealed end 5 to be inserted iTltO the body of the slug may comprise a separate tucking assembly, at least a portion of which is axially movable relative to the first mandrel. In certain embodiments of the invention, the inner member may be moved inside a recess provided on said first mandrel. Preferably, 1() however, the apparatus comprises means for moving the casing relative to the first mandrel, to provide a gap between the sealed end and the end of the first mandrel. This may be a movable clamp or the like for engaging with the casing.

Movement of the first mandrel or a portion of the first 15 mandrel may instead or also be used to provide the gap.

The apparatus may further comprise restraining means for preventing movement of the casing during the inserting step; the restraining means may comprise a clamp. (conveniently this clamp may also be used for moving the casing.

9() The apparatus may comprise a plurality of first mandrels for supporting tubular casing slugs. The plurality of first mandrels may be selectively presentable to the clamping means, to allow clamping of a selected one of the casing slugs. Alternatively, or-in addition, a plurality of clamping 95 means, rotation means, free end folding means, and inserting means may be provided, to allow sealing of multiple tubular casings simultaneously.

The apparatus may include means for retaining a

( plurality of tubular casings, and for directing said casings to said first mandrel. The retaining means may comprise a hopper or the like. Conveniently the apparatus further comprises a belt holder located between the hopper and the first mandrel. Tr-certain embodiments of the invention, there may further be provided means for producing a free end portion of a tubular casing; for example, a gripper or the like for pulling out a free end of a casing on the belt holder. 1() There may further be provided a cutter for cutting a pulled free end to a desired length and shape.

According to a third aspect of the present invention, there is provided a tubular casing sealed at one end, the seal comprising a twist formed in the casing and a 15 double-layered end portion of the casing, the sealed end and end portion of the casing being inserted inside the body of the casing such that the end portion of the casing is at least partly compressed within the body.

These and other aspects of the present invention will 0() now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a longitudinal cross-sectional view of a apparatus for sealing tubular casings in accordance with an embodiment of one aspect of the present invention; 95 Figures 2a to 2w illustrate successive steps of a method for sealing a tubular casing using one embodiment of an aspect of the present invention; Figures 3a to 3g illustrate in more detail successive

() stages in the pushing steps of the method for sealing a tubular casing of Figure 2; and Figures 4 and 5 SLOW side and perspective views respectively of an apparatus for sealing tubular casings in accordance with -I further embodiment of the present invention. Referring first of all to Figure 1, this shows a longitudinal cross-sectional view of an apparatus for sealing tubular casings in accordance with an embodiment of one 1() aspect of the present invention. The apparatus 10 comprises l opposed first and second mandrels 12, 14.

The first mandrel 12 is mounted on two piggybacked Godless air cylinders L6, 18, which are used to move the first mandrel 12 towards and away from, and left and right 15 with respect to, the second mandrel 14. Also provided on the first mandrel 12 are a pair of pneumatic grippers 20.

These grippers 20 nay be used to engage and release a slug of sausage casing 58, shown in broken outline, located on the first mandrel 12, in order to move the slug along the 9() mandrel. The end portion of the first mandrel 12 comprises a tip 22 which is of lesser diameter than the body of the first mandrel 12.

The second mandrel 14 is itself mounted on a ball-screw drive 24, driven by a stepper motor 26, for moving the 05 mandrel 14 with respect to the first mandrel 12. A second stepper motor 28 powers a belt drive 30 which is used to rotate the second mandrel 14 about mandrel axis 14a. Four spring return pneumatic -trippers 32 are provided around the

( l () second mandrel 14, with padded gripping surfaces 34 for gripping a free end 60 of the sausage casing 58 as will be later described.

In use, the apparatus 10 operates as follows. The slug 5 of whirred sausage <easing 58 is loaded into the first mandrel 12 with its free end 60 extending beyond the mandrel. Th first mandrel 12 is moved toward the second mandrel 14, which enters the free end 60 ot the casing. Pneumatic grippers 32 are actuated to press against the second mandrel 14, and so l() grip the free end 6() of the casing 58 against the second mandrel 14, which is then rotated relative to the first mandrel 12 by the second stepper motor 28 and belt drive 30 to form a twist in the casing. The grippers 32 then I disengage, and the mandrels are moved closer together, so IS that the tip 22 of the first mandrel 12 enters a recess 33 provided in the second mandrel 14, thereby folding the casing slug over itself as will be later described in detail. The end portion of the slug is then tucked inside the body of the slug to complete the seal, using a tucking assembly (not 9() shown), which may be moved into alignment with the first mandrel in place of the second mandrel.

Methods of resting a seal according to the present invention will now be described in greater detail, with reference to figures 2 and:3.

25 Figures 2a-2w show successive steps in a method for I sealing a tubular casing, using the apparatus of Figure 1.

Figure 2a shows a first mandrel 50 having an end portion 52 of reduced diameter and a slug of shirred tubular edible food

ll casing 58, having a free end portion 60, and a main body portion 62. As shown in Figures 2b to 2d, the slug 58 is first fed onto the first mandrel 50; this may be automated or may be done manually.

5 In order to form a seal in the slug 58, the first mandrel 50 is then aligned with a second mandrel 54 (Figure 2e) having a hollow tubular end portion, arid a set of grippers 32 located thereon.

The second mandrel 54 is then advanced toward the first 1() mandrel 50, until the reduced diameter end portion 52 is received within the hollow tubular end portion of the second mandrel 54 (figure 2f), after which the slug 58 is advanced aloTlg the first mandrel (figure 2g) until the grippers 32 of the second mandrel 54 may engage the free end portion 60 of 15 the slug 58.

The second mandrel 54 is then retracted slightly and rotated (figure 2h) to create a twist 64 in the casing slug 58. Further retraction and twisting pulls The twist clear of the first mandrel '0 (figure 2i) and creates a knot in the 2() casing (figure 2j). The grippers 32 are then released (figure 2k), and the second mandrel 54 advanced toward the first mandrel 50, pushing the reduced diameter portion 52 and the twist 64 inside the second mandrel 54 (figure 21) to fold the free end portion 60 of the casing slug 58 over the twist 25 64 to create a double thickness end portion 66 of the slug 58 (figure 2m). The second mandrel is then withdrawn from the first mandrel, while rotating to release the double thickness end portion 66.

l? The second mandrel 54 is then moved out of alignment with the first mandrel 50, and replaced with a tucking assembly 68, including an axially moveable protrudable inner finger portion 70, and an annular outer sleeve 72 (figure 5 2n).

The annular sleeve 72 is advanced over the double thickness end portion G6 of the slug (figure 20) to secure the end portion 66, and the slug 58 is then gripped and moved forward in unison with the sleeve to remove the end portion 1() 66 of the slug 58 from the first mandrel 52 (figure 2p). The slug movement may be used to push the sleeve while moving the slug. The inner finger portion 70 of the tucking assembly 68 is then brought forward (figure 2q), causing the twist portion 64 and the double casing thickness portion 66 of the 15 casing slug 58 to be pushed inside the main body portion 62.

This process is shown in more detail in figure 3. Finally, the tucking assembly 68 is removed from the first mandrel (figure 2r) and the sealed casing slug 58 removed and is ready for use (figures 2s to 2w).

I) Figures 3a to 3g illustrate in more detail the tucking process as outlined in Figures 2n to 2r. Figure 3a represents the state of the slug 58, first mandrel 50, and tucking assembly 68 after the end seal and double thickness portion have been formed. The sleeve 72 is then brought 5 forward to abut the first mandrel 50, such that the reduced diameter portion 52 and end portion of the slug 58 are received within the sleeve 72. The finger portion 70 is held withdrawn from the sleeve 72 to allow the reduced diameter portion 52 to enter the sleeve 72 (figure 3b). The slug 58

is then clamped by grippers 20 against the first mandrel 50 (figure 3c), and the grippers 20 are then moved forward while the sleeve 72 is moved back, to push the slug 58 forward and remove the reduced diameter portion 52 from the sleeve 72, while leaving the seal and end portion of the slug inside the sleeve (figure 3d).

With the grippers 20 still engaged, to hold the slug in place, the finger portion 70 is brought forward to contact the end of the slug 58 (figure Be). As the finger portion 70 I() is brought further forward (figure 3f), the end portion of ill the slug 58 is compressed in a concertina fashion and brough inside the body of the slug 58. Once the finger portion 70 touches the end of the reduced diameter portion 52, the end portion of the slug is fully tucked in and partially 15 compressed, and the grippers 20 are disengaged (figure 3g and the finger portion /0 retracted. The slug 58 may then be released from the mandrel, as indicated in figures 2t to 2w The end portion of the slug 58 is thus within the slug body, but does not extend far enough rearwardly to risk being 0() contacted by a stuffing horn when being filled.

A second embodiment cuff an apparatus for sealing tubular casings in accordance with the present invention is shown in side and perspective views respectively in Figures 4 and 5.

The apparatus 110 is generally similar to the above 25 described apparatus illustrated in Figure 1. In this apparatus, however, five first mandrels 112 are provided, mounted on a rotatable mounting plate 113. The rotatable mounting plate 113 may be actuated to bring a selected one of

l] the first mandrels 112 having a casing loaded thereon into alignment with the second mandrel 114, to allow the formation of an end seal in a casing located on the selected first mandrel 112, much as described above.

5 The apparatus L10 further includes an automatic hopper 162 into which a number of casings 158 may be loaded. The automatic hopper 1G2 passes the casings 158 one at a time onto a belt holder 164, where a combined gripper and cutter 166 grips and pulls out a free end of the casing 158 to a l() predetermined desired length, and cuts the free end square.

A finger (not showrl) is then actuated to push the casing 158 onto one of the first mandrels 112 adjacent the belt holder 164. As the mounting plate 113 rotates to present a loaded casing to the second mandrel 114, a fresh first 15 mandrel 112 is brought into alignment with the belt holder 164. In this way, the apparatus 110 can perform many of the actions necessary to seal casings in parallel, thereby increasing the potential output of the apparatus 110.

Further, casings may be pre-loaded into the hopper, and 2() presented to the mandrels for processing without requiring user intervention.

Numerous modifications may be made to the invention herein described. For example, after the folding step, the sealed slug of casing may be removed from the apparatus by 25 mechanical meals, for transfer to a sausageproducing machine; or may he removed by hand. Further finishing may also be conducted by hard.

Yet further, while the described embodiments have a (

1> stationary first mandrel and a rotary second mandrel, these could be reversed, with the first mandrel rotating. In addition, either or both of the mandrels may perform all necessary movement, depending on the arrangement desired.

It can be seen from the foregoing that the present invention provides a simple yet effective method of forming a seal in a tubular casing, having particular application in the food industry.

Claims

1. A method of sealing a tubular casing, the method comprising the steps of: supporting a slug of tubular casing on a mandrel to 5 define an open free end portion and a main body portion of the slug; clamping said open free end portion; rotating said open free end portion relative to said main body portion to create a twist in the casing; 10 folding said free end portion over said main body portion to create a sealed end and an end portion of double casing thickness near said sealed end; and inserting said sealed end and said end portion of double casing thickness inside said main body portion, such 15 that said end portion is at least partly compressed within the main body portion.

2. A method as claimed in claim 1 wherein the compressed end portion expands steadily as the filling is injected into the slug, further reducing the possibility of the 20 filling bursting the slug.

3. A method as claimed in claim 1 or claim 2 wherein the step of clamping said open free end portion comprises the steps of: inserting a second mandrel at least partly inside said

free end portion; and securing said free end portion to said second mandrel.

4. A method as claimed in claim 3 wherein securing of the free end portion to the second mandrel is achieved by 5 expanding the second mandrel to exert a force against the inside of the casing.

5. A method as claimed in claim 3 or claim 4 wherein a force is applied against the casing externally of the mandrel. 10

6. A method as claimed in any preceding claim wherein the folding step comprises the step of inserting a portion of said first mandrel into at least a portion of a tubular opening provided in said second mandrel.

7. A method as claimed in claim 6 wherein the inserting 15 step comprises pushing said sealed end and said double thickness end portion by means of a protrudable finger.

8. A method as claimed in claim 7 wherein the protrudable finger is provided within the second mandrel.

9. A method as claimed in claim 8 wherein a separate 20 tucking assembly is provided for performing the inserting step.

10. A method as claimed in any one of claims 6 to 9 wherein the inserting step further comprises restraining the body of the slug from movement prior to pushing the

(S i sealed end into the body of the slug; this being achieved by clamping the body of the slug to the first mandrel.

11. A method as claimed in any one of claims 3 to 10 wherein the sealed end is pushed into a recess provided 5 within the first mandrel.

12. A method as claimed in any one of claims 3 to 10 wherein the slug is moved with respect to the first mandrel to provide a gap between the sealed end and the end of the mandrel; the sealed end is then pushed or inserted into 10 this gap.

13. An apparatus for sealing a tubular casing, the apparatus comprising a first mandrel for supporting a slug of tubular casing to define an open free end portion and a main body portion of the slug; clamping means for clamping 15 said open free end portion; rotation means for rotating said free end portion relative to said main body portion to create a twist in the casing; free end folding means for folding said free end portion over said main body portion to create a sealed end and an end portion of double 20 thickness near said sealed end; and means for permitting said sealed end and said end portion of the slug to be inserted inside said main body portion, such that said end portion is at least partly compressed within the main body portion.

in

14. Apparatus as claimed in claim 13 wherein the apparatus further comprises a second mandrel moveable relative to the first mandrel for insertion at least partly into the open free end portion of the casing.

5

15. Apparatus as claimed in claim 13 or claim 14 wherein the clamping means comprises a plurality of expandable fingers provided on the second mandrel; expansion of these fingers while located within the casing causing the mandrel to clamp the casing.

10

16. Apparatus as claimed in claim 13 or claim 14 wherein the clamping means comprises an external clamp for applying pressure to the casing against the second mandrel.

17. Apparatus as claimed in any one of claims 13 to 16 wherein said rotation means comprises means for rotating 15 one of said first and second mandrels relative to the other of said first and second mandrels.

18. Apparatus as claimed in claim 17 wherein the rotation means comprises a belt-driven stepper motor operatively associated with the second mandrel.

20

19. Apparatus as claimed in claim 17 wherein said rotating means may be a direct motor, a rotary motor, or the like.

20. Apparatus as claimed in any one of claims 13 to 19 wherein the free end folding means comprises a hollow tubular portion provided on the second mandrel, and means

All for inserting said sealed end of said casing at least partly into said hollow tubular portion.

21. Apparatus as claimed in claim 20 wherein the means for inserting said sealed end into the hollow tubular portion 5 comprises an axially moveable inner member provided within said first mandrel, which inner member is moved inside said second mandrel.

22. Apparatus as claimed in claim 20 wherein said insertion means comprises means for moving said second 10 mandrel relative to said first mandrel such that the first mandrel is received at least partly within said hollow tubular portion of said second mandrel.

23. Apparatus as claimed in any one of claims 13 to 22 wherein the means for permitting the sealed end to be 15 inserted into the body of the slug comprises an axially moveable inner member provided within said second mandrel.

24. Apparatus as claimed in any one of claims 13 to 22 wherein the means for permitting the sealed end to be inserted into the body of the slug comprises a separate 20 tucking assembly, at least a portion of which is axially movable relative to the first mandrel.

25. Apparatus as claimed in any one of claims 13 to 24 wherein the apparatus comprises means for moving the casing relative to the first mandrel to provide a gap between the

( sealed end and the end of the first mandrel.

26. Apparatus as claimed in any one of claims 13 to 24 wherein movement of the first mandrel or a portion of the first mandrel is instead, or also, used to provide a gap.

5

27. Apparatus as claimed in any one of claims 13 to 26 further including restraining means for preventing movement of the casing during the inserting step; said restraining means comprising a clamp.

28. Apparatus as claimed in claim 27 wherein said clamp is 10 also used for moving the casing.

29. Apparatus as claimed in any one of claims 13 to 28 wherein the apparatus comprises a plurality of first mandrels for supporting tubular casing slugs.

30. Apparatus as claimed in claim 29 wherein the plurality 15 of first mandrels is selectively presentable to the clamping means, to allow clamping of a selected one of the casing slugs.

31. Apparatus as claimed in claim 29 or claim 30 wherein a plurality of clamping means, rotation means, free end 20 folding means and inserting means is provided to allow sealing of multiple tubular casings simultaneously.

32. Apparatus as claimed in any one of claims 13 to 31 wherein apparatus includes means for retaining a plurality of tubular casings, and for directing said casings to said

first mandrel.

33. Apparatus as claimed in claim 32 wherein the retaining means comprises a hopper or the like.

34. Apparatus as claimed in claim 33 wherein the apparatus 5 further comprises a belt holder located between the hopper and the first mandrel.

35. Apparatus as claimed in any one of claims 13 to 34 wherein there is provided means for producing a free end portion of a tubular casing; for example, a gripper or the 10 like for pulling out a free end of a casing on the belt holder.

36. Apparatus as claimed in any one of claims 13 to 35 wherein said apparatus includes a cutter for cutting a pulled free end to a desired length and shop.

15

37. A tubular casing sealed at one end, the seal comprising a twist formed in the casing and a double layered end portion of the casing, the sealed end and end portion of the casing being inserted inside the body of the casing such that the end portion of the casing is at least 20 partly compressed within the body.

38. Apparatus substantially as hereinbefore described with reference to Figures 1 to 3 or to Figures 4 and 5 of the drawings.

39. A method substantially as hereinbefore described.