NZ293559A - Welding rail for a vacuum packing machine with wire retained in pivoting rocker and with tensioning to exert pressure on rocker - Google Patents

Description

New Zealand No. 293559 International No. PCT/CH95/00237 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 16.10.1994; Complete Specification Filed: 13.10.1995 Classification:(6) B29C65/22 Publication date: 24 June 1997 Journal No.: 1417 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Welding rail for a vacuum packing machine Name, address and nationality of applicant(s) as in international application form: INAUEN MASCHINEN AG, Melonenstrasse 2, CH-9100 Herisau, Switzerland New Zealand No. 293559 International No. PCT/CH95/00237 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention: Welding rail for a vacuum packing machine Name, address and nationality of applicant(s) as in international application form: INAUEN MASCHINEN AG, of Melonenstrasse 2, CH-9100 Herisau, Switzerland, a oD/v\pOr^| WO 96/11789 \ PCT/CH95/00237 Welding rail for a vacuum packaging m&china The present invention relates to a welding rail for a vacuum packaging machine, with an elongate basic body, with at least one track for attaching a wire to 5 this rail and with fastening devices for the end portions of the wire, these fastening devices being accommodated in the end portions of the basic body of the rail.

Welding rails serve, in vacuum packaging machines, for the closing of bags filled with articles, 10 after the interior of said bags has been evacuated. As a rule, two such rails are located opposite one another in the machine and the mouth of the bag is clamped and welded together between these rails. The welding rails have, as a rule, a length of several decimeters, and they 15 carry two wires which are located at a distance of about 5 mm from one another. One of the wires welds the two walls of the bag together and the other wire severs the excess free end portion of the bag mouth.

So that the weld seam and the severing edge are 20 straight and therefore no short circuit occurs between the two conductors running in parallel next to one another, it is very important that the two wires be tensioned as well as possible. For this purpose, a sprung jaw has hitherto been accommodated in the respective end 25 portion of the rail basic body, one of the end portions of the respective wire being deflected via said jaw. The spring presses the jaw in the longitudinal direction of the rail basic body, specifically away from the latter. This wire end then passes into a clamping device, where 30 this end of the wire has been clamped by tightening a screw, usually a grub screw. In order to achieve the desired tension in the wire, it is necessary first to pull very strongly with pincers or the like on the wire end portion projecting from the clamping device and then 35 to tighten the screw.

While the wires are being attached it is very difficult for one person to hold the rail body, pull firmly on the wire end by means of pincers and tighten WO 96/11789 - 2 - PCT/CH95/00237 the respective grub screw, in order to fix the tension achieved in the wire.

The object o£ the present invention is to eliminate this disadvantage and also further disadvan-5 tages of the previous welding rails.

In the welding rail of the generic type mentioned in the introduction, this object is achieved, according to the invention, as defined in the characterizing clause of Claim 1.

Embodiments of the present invention are explained in more detail below by means of the accompanying drawings, in which: Figure 1 shows a top view of the underside of one of the end portions of the present welding rail, Figure 2 shows a vertical section II-II through the end portion of the present rail according to Figure 1, said rail containing a fastening device, and Figure 3 shows the fastening device from Figure 2 enlarged.

The welding rail represented in Figures 1 to 3 has an elongate basic body 1 of quadrangular cross-section. In the instance shown, this basic body 1 is of rectangular cross section, one of the narrower sides 2 of such a parallelepiped forming the underside of this rail. 25 The opposite narrow side 3 of this rail constitutes its top side.

Tracks 5 and 6 for wires 7 and 8 are provided on the rail underside 2. One of these wires serves for welding together the walls of a packaging bag. The other 30 wires serves for the immediately subsequent severance of the excess end portion of this bag mouth. In the instance shown, the wires 7 and 8 have a rectangular cross-section, and they rest with their wider side on the underside 2 of the rail basic body 1. As a rule, however, 35 only one of these wires has a rectangular cross-section. The other wire has a circular cross-section. Made in the end face 4 of the rail basic body 2 are vertically extending indentations 11 and 12, into which the end portions 9 of the wires 7 and 8 are bent out of the WO 96/11789 - 3 - PCT/CH9S/00237 straight position on the underside 2 of the basic body 1.

Recesnes 13 and 14 are made in this basic body 1 from the top side 3 of the rail body 1, in such a way that a pair o£ these successive recesses 13 and 1<:\ 5 constitutes a continuation of one of the indentations 11 or 12 in each case. The sectional representation according to Figures 2 and 3 shows only one pair of these recesses 13 and 14, which adjoins the second indentation 12. The first recess 13 is located nearer the end face 4 10 of the basic body 1 and at one end adjoins the indentation 12, specifically in the region of a bottom 15 of the indentation 12. The first recess 13 is substantially deeper than the second recess 14, which adjoins the other end of this first recess 13 in the region of an inner 15 wall 16 of the rail body 1. The three cavities 12, 13 and 14 mentioned therefore lie in a common vertical plane.

Threads into which screws 17 can be screwed are made in the bottom of the second and shallower recess 14. A soldering lug 18, to which a cord 19 is soldered at one 20 end, can be clamped under the head of the respective screw 17. The cords 19 serve for supplying the wires 7 and 8 with electrical current which is necessary for closing the evacuated bags. One of these soldering lugs 18 is connected, in each case via one of the cords 19, to 25 one of the wires 7 or 8. At the same time, it is also possible to clamp under the respective screw 17 a second soldering lug (not shown), via which current can be supplied to this point on the welding rail from outside.

The welding rail also has fastening devices 10 30 for the end portions 9 of the wires 7 and 8, said fastening devices being accommodated in the deeper recess 13 of the respective end portion of the basic body 1 of the present welding rail. Each of the wire ends 9 is assigned such a fastening device 10, so that the rail, which is 35 provided with two wires 7 and 8, contains four such fastening devices 10. The fastening device 10 comprises a rocker 20 and a pressure device 40 which can act on this rocker 20.

The rocker 20 is designed, in principle, as a WO 96/11789 - 4 - PCT/CH95/00237 two-armed lever which is pivotably mounted in one of the end portions of the basic body 1 of the rail. The rocker has a basic body 21 which is quadrangular in principle, the upper side 211 and the lower side 212 of this rocker basic body 21 running virtually parallel to the top side 3 and underside 2, respectively, of the rail basic body 1. The rocker basic body 21 is provided with a bore 22 which runs perpendicularly to the larger side faces of this basic body 21. Through this bore 22 passes 10 a first pin 23 which is mounted in the side walls of the recess 13 in the rail basic body 1. The rocker 20 cam thus pivot about this pin 23. The pin 23 is arranged in a region of the deeper recess 13, said region being located near the end face 4 of the rail basic body 1. 15 The rocker 20 is provided with means for retai ning the wire end 9. That region of the rocker basic body 21 which is located between the rail end wall 4 and the pin 22 is provided with a duct 24, in which the wire .end 9 lies. A threaded bore 25 is made in this first region of the rocker basic body 21 from the rail end face 4, the axis of said threaded bore being virtually perpendicular to the axis or the duct 24. The threaded bore 25 opens into the duct 24, so that the tip of a screw 26, which is screwed in this bore 25 and which advantageously is a 25 grub screw, can penetrate into the interior of the duct 24 and hold the wire end 9 in place in the duct 24.

The duct 24 is directed obliquely upward in relation to the underside 2 of the basic body 1 of the rail and, at the same time, is inclined backward somewhat 3 0 in relation to the straight middle part of the wire 7 or 8, so that most of the tension of the middle part of the wire 7 or 8 can be absorbed by the walls of the duct 24 of the rocker 20. In this case, the point of engagement of the screw 26 on the wire end 9 is then subjected to 35 less tensile stress by the tension in the wire 7 or 8. The angle alpha between the straight middle part of the wire 7 or 8 and the axis A of the duct 24 is approximately between 50 and 80 degrees. However, the position of the axis A in relation to the straight middle WO 96/11789 - 5 - PCT/CH95/00237 part of the wire 8 changes a little with the change in position of the rocker 20 in relation to the underside 2 of the rail, specifically depending on how the tension in the wire 7 or 8 changes.

A stop 28 projects from the underside 212 of the rocker basic body 21 and has a stop face 281 extending virtually vertically and a clamping face 282. This stop 28 is located between the bent portion of the wire end 9 and the end face 15 in the interior of the indentation 10 12. The stop face 281 of this stop 28 confronts the end face 15 and normally rests on this end face 15 when the wire end 9 is introduced into the duct 24 and when the grub screw 26 is tightened. When the pressure device 40 then exerts pressure on the rocker 20, the stop face 15 29 [sic] is, as a rule, at a distance from the end face 15 of the rail basic body 1. The clamping face 282 of the stop 28 is convex and its contour corresponds essentially to the shape of the bent wire portion 9. The stop 28 exerts tension on the middle portion of the wire 7 or 8 20 via this clamping face 282.

That half of the rocker basic body 21 which is located behind the first pin 23 in respect of the rail end face 4 is provided with a spur 30 projecting from the respective side face 213 of the rocker basic body 21. The 25 top side or the back 31 of this spur 30, although being inclined slightly downward, adjoins the top side or the back 211 of the middle portion of the rocker basic body 21. The apur 30 constitutes an extension of the second rocker arm and, at the same time, also an engagement face 3 0 for the pressure device 40.

A blind hole 32 is made in the rocker basic body 21 from the last-mentioned side face 213, said blind hole being directed approximately towards the first pin 23. The outer mouth of this blind hole 32 is located under 3 5 the spur 30. The second end portion of the cord 19 lies in this blind hole 32. A threaded bore 33, in which a screw 34 is screwed, is made from the top side 31 of the spur 30 or the top side of the rocker basic body 21. This threaded bore 33 opens into the blind hole 32, so that WO 96/11789 - 6 - PCT/CH95/00237 this second end of the cord 19 can be retained in the blind hole 32 by the screw 34.

The pressure device 40 is accommodated in the interior of the deeper recess 13 in the end portion of 5 the rail basic body 1 and is likewise pivotably mounted here, in this case being pivotable in the same plane as the rocker 20. This device 40 comprises a carrier 41 which has the shape of an essentially quadrangular plate. This plate 41 is at a distance from the rocker 20. A bore 10 42, through which a pin 43 passes, is made perpendicularly to the larger base faces of the plate 41. The end portions of this second pin 43 are mounted in the walls of the rail basic body 1.

The top side 44 of the carrier 41 is plane and a 15 strap 45 rests on this carrier top side 44. This strap 45 is designed as a straight material strip, the length of which is larger than the length of the top side 44 of the carrier 41. Screws 46 and 47 are provided, which pass freely through the strap 45 and are screwed in correspon-20 ding threaded holes in the carrier 41. End portions 48 and 49 of the strap 45 project horizontally from the carrier 41 on the left and right of the carrier 41. The underside of the first strap end portion 48 rests on the back 31 of the spur 30 of the rocker 20. The other end 25 portion 49 of the strap 45 rests on one of the end portions of a vertically acting compression spring 50. The other end portion of this compression spring 50 rests on the bottom 51 of the recess 13.

When one of the wires 7 or 8 is to be inserted 3C into the welding rail, the straps 45 of the respective fastening devices 10 in the end portions of the rail basic body 1 are removed from the carriers 41. The end portions 9 of the wire 7 or 8 are then fed into the ducts 24 of these fastening devices 10 and the screv.i 26 are 35 tightened. When the screws 26 are being tightened, it is expedient if the stop face 281 of the respective rocker 20 rests on the end face 15 of the rail basic body 1. This is because, in this position of the rocker 20, the back 31 of the spur 30 reaches its highest position.

WO 96/11789 - 7 - PCT/CH95/00237 After the fastening screws 26 have been tightened, one of the straps 45 is screwed onto one of the carriers 45 [sic] .

When the strap 45 is then screwed onto the carrier 41 of the second fastening device 10, resistance is detected when the screws 46 and 47 are being screwed in, specifically when the strap 45 is still at some distance from the carrier 41. This resistance occurs because the first strap end 48 rests cn the upwardly pivoted spur 30 of the rocker 20 and the second strap end 49 rests on the upper end of the compression spring 50. When the screws 46 and 47 are then tightened further, the spur 30 on the rocker 20 is pressed downward by the strap 45 and the rocker 20 is pivoted in the clockwise direction. At the same time, the stop body 28 moves away from the end face 15 on the rail basic body 1 and, via the clamping face 28 on the stop 28, tension is generated in the middle portion of the wire 7 or 8. The amount of this tension can be selected in a simple way by means of the compressive force of the spring 50.

When the wire 7 or 8 is being tensioned, the rail can be held in one hand and, by means of a screwdriver held in the other hand, the tension in the wire 7 or 8 can be fixed in a simple and convenient way merely by tightening the screws 46 and 47.

Claims (4)

WO 96/11789 - 8 - PCT/CH95/00237 Patent claims

1. Welding rail for a vacuum packaging machine, with an elongate basic body (1), with at least one track (5; 6) for attaching a wire (7;8) to this rail and with faste-5 ning devices (10) for the end portions of the wire, these fastening devices being accommodated in ti.e end portions of the basic body of the rail, characterized in that the fastening device (10) has a rocker (20) which is pivo-tably mounted in one of the end portions of the basic 10 body (1) of the rail, in that this rocker is provided with means for retaining one of the end portions (9) of the wire (7;8), and in that a device (40) is provided, by means of which pressure which is necessary for tensioning the wire can be exerted on the rocker (20). 15

2. Welding rail according to Claim 1, characterized in that the rocker (20) is designed as a two-armed lever, in that a duct (24), through which one of the ends (9) of the wire cam be guided, is made in one of these arms, in that this duct (24) is assigned a holding member (26), 20 for example a screw, which can firmly clamp the end portion of the wire (9), and in that the second arm (30) of the rocker (20) has an engagement face (31) for the pressure device (40).

3. Welding rail according to Claim 1, characterized 25 in that the pressure device (40) has a strap (45) and a carrier (41) for this strap (45), in that the strap (45) has end portions (48, 49) which project from the opposite sides of this carrier (41) , in that the first of these end portions (48) of the strap (45) rests on the engage-30 ment face (31) of the rocker (20), and in that the other end portion (49) of the straps (45) rests on a compression spring (50) which, at the other end, rests in the interior of the rail basic body (1).

4. Welding rail according to Claim 3, characterized 35 in that the carrier (41) is designed as a plate which is pivotably mounted in the interior of the end portion of the rail basic body (1), specifically in the same plane as the rocker (20), in that the carrier (41) is arranged next to the rocker (20) at a distance from the latter, in 2^3553 WO 96/11789 - 9 - PCT/CH95/00237 that the carrier is provided on its circumference with a face (44) which is designed for receiving the strap (45), and in that the strap (45) can be fastened on the carrier (41) by means of screws (46, 47). EHD OF CLAIM!