CA2002419A1 - Apparatus for welding plastic foils - Google Patents
Apparatus for welding plastic foilsInfo
- Publication number
- CA2002419A1 CA2002419A1 CA002002419A CA2002419A CA2002419A1 CA 2002419 A1 CA2002419 A1 CA 2002419A1 CA 002002419 A CA002002419 A CA 002002419A CA 2002419 A CA2002419 A CA 2002419A CA 2002419 A1 CA2002419 A1 CA 2002419A1
- Authority
- CA
- Canada
- Prior art keywords
- pressure
- arm
- bridge piece
- arms
- bearing sleeve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
- B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
- B29C65/18—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools
- B29C65/20—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated tools with direct contact, e.g. using "mirror"
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/01—General aspects dealing with the joint area or with the area to be joined
- B29C66/05—Particular design of joint configurations
- B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
- B29C66/11—Joint cross-sections comprising a single joint-segment, i.e. one of the parts to be joined comprising a single joint-segment in the joint cross-section
- B29C66/112—Single lapped joints
- B29C66/1122—Single lap to lap joints, i.e. overlap joints
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/40—General aspects of joining substantially flat articles, e.g. plates, sheets or web-like materials; Making flat seams in tubular or hollow articles; Joining single elements to substantially flat surfaces
- B29C66/41—Joining substantially flat articles ; Making flat seams in tubular or hollow articles
- B29C66/43—Joining a relatively small portion of the surface of said articles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C66/00—General aspects of processes or apparatus for joining preformed parts
- B29C66/80—General aspects of machine operations or constructions and parts thereof
- B29C66/83—General aspects of machine operations or constructions and parts thereof characterised by the movement of the joining or pressing tools
- B29C66/836—Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table
- B29C66/8362—Rollers, cylinders or drums moving relative to and tangentially to the parts to be joined
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
- Treatment Of Fiber Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An apparatus for welding plastic foils has only a single motor to drive the two pressure rollers. This is arranged within the bridge piece of a U- shaped housing or within a tubular pressure element of a pressing element, which is arranged at a distance from and parallel to the bridge piece.
The welding apparatus is particularly suitable for performing welding operations in a vertical plane or overhead, as required, for instance, when lining tunnels. The welding apparatus is a light and compact and particularly convenient to use.
An apparatus for welding plastic foils has only a single motor to drive the two pressure rollers. This is arranged within the bridge piece of a U- shaped housing or within a tubular pressure element of a pressing element, which is arranged at a distance from and parallel to the bridge piece.
The welding apparatus is particularly suitable for performing welding operations in a vertical plane or overhead, as required, for instance, when lining tunnels. The welding apparatus is a light and compact and particularly convenient to use.
Description
~19 The present invention relates to an apparatus for welding plastic foils of the type comprising an essentially U-shaped housing formed from two arms and a bridge piece that joins the two arms together, the arms being rotatable relative to each other about the longitudinal axis of the bridge piece, a powered pressure roller arranged on each of the unattached ends of each arm, a pressing mechanism pressing the pressure rollers together, and a heating element.
DE-GM 83 01 191 describes a welding apparatus with an essentially U-shaped housing, in which at the ends of the two housing arms that lie in different planes, and the angular position of which can be varied relative to each other, there is an over-hung pressure roller. Each of the pressure ; rollers is connected through an appropriate gearing system to a dedicated motor or to a releasable coupling through a common motor. The welding apparatus incorporates two pairs of rollers to support the lower of the two plastic foils that are to be welded together or the base or sublayer.
DE-OS 35 35 760 describes another mobile welding apparatus with an essentially U-shaped housing, from which the rollers have been eliminated in order to save weight. In this welding apparatus, each of the pressure rollers that is arranged at the end of each housing arm has a dedicated motor and a dedicated reduction gearing. The motors and the gearing are arranged coaxially to the appropriate pressure rollers. Since the motors project from the sides of the housing arms, this particular welding apparatus is bulky and awkward.
It is an object of the present invention to provide a mobile apparatus for welding plastic foils, which not only weighs as little as possible but is also of compact construction and particularly convenient to use.
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20(~2419 According to the present invention there i5 provided in an apparatus for welding plastic foils comprising a substantially U-shaped housing formed from two arms, a bridge piece joining said arms together, said being rotatable relative to each other about the longitudinal axis of the bridge piece, a powered pressure roller arranged on each of the free ends of each arm, a pressing mechanism for urging the pressure rollers together, and a heating element, the improvement wherein a geared motor is arranged on the bridge piece to drive both of the pressure rollers, said motor having two opposing outputs which drive the two pressure rollers in opposite directions through a gear system.
Because of the fact that a geared motor that is used to drive the pressure rollers and which has two opposing outputs that are each connected through gears to the associated pressure roller is arranged on the cross-piece of the U-shaped housing, it has been possible, on the one hand, to reduce the weight of the apparatus by eliminating one motor and, on the other, to arrive at a more compact construction by eliminating parts that project beyond the sides of the housing. As a consequence of these two advantageous characteristics, the welding apparatus configured according to the present invention is particularly suitable for the production of tunnel linings, in which, when welding is being carried out on vertical walls or overhead, the whole weight of the welding apparatus has to be borne by one operator.
The use of a single motor for both pressure rollers entails the added advantage that the pressure rollers always run synchronously with each other.
An even more compact construction can be achieved by arranging the geared motor within the tubular bridge piece that is closed in around its periphery, which entails the additional advantage that the geared motor is encapsulated and th~s protected against dirt and damage.
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20024~9 If the drive motor for the pressure rollers is arranged within a tubular pressure element of the pressing mechanism at a distance from and parallel to the bridge piece of the U-shaped housing and the drive motion of the motor to the two geax systems that are connected with the pressure rollers is split with the help of a shaft that is supported within the bridge piece, it is possible to use a geared motor with only one output as the drive motor. A geared motor that has only one output is narrower by the length of the gearing that has been eliminated, which makes it possible to make the housing of the apparatus, i.e., the bridge piece and the pressure element correspondingly narrower. Even though the saving in weight brought about by the elimination of one gear system for the geared motor may be balanced out by the shaft in the bridge piece that is now required and the additional gearing that connects the shaft with the geared motor, the reduction in the length of the bridge piece, of the pressure element, and of the bearings for the pressure rollers will result in a further and perceptible reduction in weight of the whole system.
However, of even greater signi~icance is the advantage that because of the reduction in the weight of the housing the apparatus can be made much narrower and thus, overall, more compact and consequently considerably more convenient.
By making the operating lever adjustable into a position that is essentially parallel to the housing arm that supports it, once the arms have been moved into the working position, it is also possible to arrive at a comparatively flat construction for the apparatus.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a plan view of the welding apparatus;
Figure 2 is a cross sectional drawing taken on the line II-II
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in figure l;
Figure 3 is a cross section taken on the line III-III in figure l;
Figure 4 is a plan view of the welding apparatus of a second embodiment;
Figure 5 is a further view of the welding apparatus;
Figure 6 is a side view of the welding apparatus;
Figure 7 is a sectionized plan view of the welding apparatus in a third embodiment;
Figure 8 is a partially cross-sectioned side view of the welding apparatus;
Figure 9 is a side view of the pressure arm clamped onto the pressure element; and Figure 10 is a cross sectional view of the adjusting . 15 mechanism for the pressure arm, taken on the line IV-IV in : figure 2.
The welding apparatus shown in figures l to 3 has an essentially U-shaped housing 1 that consists of two arms 2 and 3 and of a bridge piece 4 that connects these arms with each other. The arms 2, 3 are hollow and each has a removeable side wall 5, 6.
The bridge piece 4 is formed from two bearing sleeves 7, 8 that can telescope into each other, of which the outer bearing sleeve 7 is rigidly c'onnected to the arm 2 and the inner bearing sleeve 8 is rigidly connected to the arm 3.
The inner bearing sleeve 8 consists of an annular part 9, a pipe section lO and an extended hub 11, these parts being connected rigidly to each other by welds. The hub 11 incorporates a flange 12, a base part 13 with relatively thicker walls, and an extension 14. At the end of the outer bearing sleeve 7 there is a stepped extension 15, and at the other end there is a cylindrical extension 16.
- The extension 16 of the outer bearing sleeve 7 lies on the ; hub 11 and together with this forms a bearing 17. A ball : , . .
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200~9 bearing 18 is arranged on the extension 14 of the hub 11 and the extension 15 of the outer bearing sleeve 7 rests on this.
The two bearing sleeves 7 and 8 are supported on each other so as to be able to rotate through the bearings 17 and 18, whic:h means that the arms 2 and 3 can also be rotated relative to each other.
Within the bearing sleeve 8 there is a known geared motor 19 that consists of a centrally arranged motor section 20 and two epicyclic gears 21, 22 that are installed outside. Each epicyclic gear 21, 22 has an output shaft 23 or 24, respectively. The geared motor 19 is connected ta the inner bearing sleeve 8 through the bearing plate 25 so as to be unable to rotate independently of this, in that the epicyclic gear 22 is bolted up with the bearing plate 25 and this is bolted up with the annular part 9. The other end of the gear motor 19 is supported in a bearing plate 26 that is bolted up with the epicyclic gearing 21 and rests with one section (not described in greatsr detail herein) on the extension 14 of the hub 11 so as to be radially supported. A shoulder 27 of 20 the bearing plate 26 presses against the inner ring of the ball bearing 18 and thus holds the outer ring of the ball ; bearing 18 in contact with a shoulder of the extension 15 of the outer bearing sleeve 7 and, on the other hand, acts as a contact surface for the face of the extension 16 on the flange 12.
A notched-belt pulley 28 is secured to the shaft 23 and a notched belt 29 passes over a notched-belt pulley 30 that is secured on a shaft 31 that floats in the arm 2. A pinion 32 is secured to the shaft 31 and this engages with a similarly floating shaft 33. A notched-belt pulley 35 is secured to the shaft 33~ The notched belt 36 also passes over the notched-belt pulley 37 that is secured to one end of a shaft 38. The shaft 38 is accommodated in a bearing sleeve 39 that is secured to the arm 2 and supports at its other end a : . -., ., , , . ,~ .
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., ~9 pressure roller 40 that is rigidly secured to this. The two pinLons 32, 34 form a reversing gear 41.
A notched-belt pulley 42 is secured to the shaft 24 and a notched belt 43 runs around this. The notched belt 43 also passes over a notched-belt pulley 44 that is secured to the end of a shaft 45. The shaft 45 is accommodated in a bearing sleeve 47 that is secured on the arm 3 and supports at its other end a pressure roller 47 that is connected rigidly to it.
An electrically heated heating wedge 49 is arranged on the arm 3 with the help of a parallel crank mechanism 48 that can be moved back and forth between the retracted rest position shown in figure 1 and a working position that is tight against the pressure rollers 40, 47, by means of a handle 50 that is connected to the parallel crank mechanism 48.
Two spring rods 51 that are parallel to each other are secured in the base part 13 of the hub 11 and these extend through an opening 52 in the outer bearing sleeve 7 and extend essentially along the arm 2. The two spring rods 51 are enclosed by two opposing double profile rollers 53, 54 that are so supported on a first supporting plate 55 as to be freely rotatable. The first supporting plate 55 is arranged so as to be adjustable on a second supporting plate 58, transversely to the longitudinal axis of the spring rods 51, this being done with the help of vertical slots 56 and corresponding screws 57. The second carrier plate 58 is arranged so as to be adjustable on a retaining plate 61, parallel to the longitudinal axis of the spring rods 51 with the help of horizontal slots 59 and corresponding screws 60.
The retaining plate 61 is arranged rigidly on the arm 2 through an interposed piece 62, which means that the carrier plate 58 can be moved on the retaining plate 61 by one or more multiples of the distance between the drilled holes.
The components 51 to 62 form a pressing mechanism 64.
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Runners 65, 66 that are triangular and rounded off at the prolecting tip are arranged on the ends of the arms 2 and 3 tha~ are ad;acent to the bridge piece 4.
The method of operation of the welding apparatus will now be described.
The welding apparatus is used to produce overlapping seams in plastic foils, this being done particularly when lining tunnels in which the welded seams are to be made mainly in a vertical plane and overhead.
The welding apparatus is so arranged between the plastic foils that are to be welded together that one plastic foil runs beneath the bridge piece 4 and the heating wedge 49 and the other plastic foil runs above the bridge piece 4 and the heating wedge 49, so that they lie directly one on top of the other between the pressure rollers 40, 47.
The welding pressure between the pressure rollers 40, 47, which is required to complete the welding procedure, is generated by the pressing mechanism 64. When the two supporting plates 55, 58 are appropriately adjusted the two spring rods 51 shown in figure 2 are tensioned downwards by the upper double profile roller 53, when a turning moment is exerted on the base part 13 that supports the spring rods 51 and thus on the inner bearing sleeve 8 and the arm 3 that is connected with it, which means that the uppermost pressure roller 47 is pressed against the pressure roller 40 that is located beneath it.
The pressing mechanism 64 can accommodate two basic adjustments, namely, on the one hand, the magnitude of the initial stressing force and on the other hand, the degree of the springing effect of the spring rods 51. The initial stressing force is adiusted by moving the supporting plate 55 transversely to the longitudinal axis of the spring rods 51.
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;~)Z4~9 The stiffness of the springing action of the spring rods 51 can be adjusted by moving or displacing the supporting plate 58 parallel to the longitudinal axis of the spring rods 51, when the effective length of the spring rods 51 is changed.
Thus, optimal operating conditions can be adjusted for specific foil materials and foil thicknesses by the two , different adjusting possibilities of the pressing mechanism ? 64. So, for example, when welding HDPE foils, it is necessary to use relatively high pressure. At the same time, in addition to the initial stressing it is also desirable to have a very stiff spring action so that when welding is being done on a construction site, dirt such as grains of sand and small stones which could accidentally get between the foils are pressed into the softened foil so that the necessary welding pressure can be maintained at these points as well.
In contrast to this, insofar as larger transition points such as, for instance, transverse seams, are to be crossed during the welding process, the springs are set for a high degree of initial stressing in order that the initial stressing force ' 20 does not have to be reduced when negotiating these cross-over points.
; Should a particularly low welding pressure be required, then work can be carried out using only one spring rod 51. In contrast to this, if extremely high welding pressure is required, then spring rods of a greater cross section can be used.
Since the whole pressing mechanism 64 as shown in figure 2 does not extend beyond the upper and lower sides of the arm 2 that supports it, the overall welding apparatus is kept very compact and convenient.
Once the welding pressure has been adjusted, the heating wedge 49 that has been heated to the required welding temperature is moved into the welding position. As soon as :
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20~ 9 this heating wadge 49 reaches the required welding position, the geared motor 19 is switched on, whereupon the welding apparatus moves relative to the foil with the help of the driven pressure rollers 40, 47, whereupon the softened areas of foil are bonded to each other so as to form a welded seam.
The welding apparatus that is shown in figures 4 to 6 is identical to the welding apparatus described in the first embodiment as far as the housing and the drive systems are concerned. The essentially U-shaped housing 1 also consists of the two arms 2, 3 as well as the bridge piece 4 that hinges these together and in which the geared motor for the pressure rollers 40, 47 (not shown in this instance) is arranged. The welding apparatus also has a heating wedge 49 that is mounted on a parallel crank mechanism 48. Further, triangular runners 65, 66 that are rounded over at the projecting tips are secured to the adjacent ends of the arms 2, 3.
; In contrast to this, the pressing mechanism 80 that is used to generate the welding pressure is of a completely different construction to the pressing mechanism 64 used in the first embodiment. The pressing mechanism 80 incorporates a rod-like pressure element 81 that is secured to the runner 65 of the arm 2 and this extends parallel to the bridge piece 4, at a distance thereto, parallel to its longitudinal axis. An angle piece 82 is secured to the unattached end of the pressure element 81 and this incorporates an L-shaped horizontal angle plate 82a. The pressure element 81 and the angle piece 82 together form a pressure beam 83. A threaded spindle 85 is secured within a rotary piece 84 that is accommodated in the runner 66 and this spindle extends through a drilled hole 86 in the runner 66 and through a drilled hole (not shown herein) in the plate 82a. Within the part of the threaded spindle 85 that is above the plate 82a there is a handle 87 and a plurality of disk springs 88 that rest on the plate 82 through the medium of a washer 89. The '.
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zo~9 components 85, 87, 88, and 89 together form a spring mechanism 90. A stop washer 91 that has a corresponding internal thread, and which can be adjusted for height, is arranged beneath the plate 82a on the threaded spindle 85.
On the arm 3 there is an angle bracket 92 on which a handle 93 or 94 that extends transversely to the arms 2, 3 is secured. A rod 95 that can be moved longitudinally is accommodated in the angle bracket 92 and the lower end of this supports a pressure piece 96 and is also connected with 10 a toggle joint system that incorporates a handle 97. The components 92 and 95 to 98 together form an adjusting mechanism 99.
Up to the point of adjustment of the welding pressure, the remaining functions of the welding apparatus are the same as in the welding apparatus described in the first embodiment, so there is no need for a more detailed description of these.
The level of the welding pressure is adjusted with the help of the handle 87. Turning the handle 87 down presses the disk springs 88 more strongly against the plate 82a and thus press the pressure beam 83 downwards as a whole. The pressure that acts on the pressure beam 83 causes a turning moment that acts in a clockwise direction as in figure 6 to be exerted on the runner 65. Because of this turning moment, the arm 2 is pivoted in a clock~ise direction as shown in figure 6, which means that the pressure roller 40 is pressed upwards against the pressure roller 47.
The overall angle between the àrms 2, 3 that are in the welding position can be limited by means of the stop washer 91, i.e., the arms or the pressure rollers 40, 47 cannot be moved further towards each other if the angle plate 82 is resting on the stop washer 91. In this way, it is possible to adjust the thickness of the welding seam within very precise limits.
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2~ 9 The arms 2, 3 can be moved apart with the help of the adjusting mechanism 99, whereupon two new foils can be introduced without any problem between the pressure rollers 40, 47. To this end, the handle 97 is swung downwards and thus the rod 95 is also moved downward. In the course of this movement, the pressure piece 96 comes into contact with the angle plate 82 that is resting on the stop washer 91 and causes the pressure beam 83, which acts in this case as a two-arm lever, to be pivoted as a whole about the stop washer 91 that now acts as a pivot axis, this pivoting movement, as shown in figure 4, taking place in a counter-clockwise direction. The pivoting movement leads to an elastic deflection of the pressure element 81 that is connected rigidly to the runner 65, whereupon a turning movement that acts in a counter-clockwise direction as in figure 6 is exerted on the runner 65 which together with the arm 2 can be pivoted about the longitudinal axis of the bridge piece 4.
As soon as this turning movement is stronger than the turning movement that is generated by the spring mechanism 90 in the opposite direction, the arm as in figure 6 is pivoted counter-clockwise, whereupon the prçssure roller 40 is moved away from the pressure roller 47.
The welding apparatus of the third embodiment has an essentially U-shaped housing 100 that consists of two arms - 25 101, 102 as well as a bridge piece 103 that joins these with each other. The arms 101, 102 are hollow and each has a removeable side wall 104, 105.
The bridge piece 103 is formed from two bearing sleeves 106, - 107 that can telescope into each other, of which the outer io bearing sleeve 106 is connected with the arm 102 and the inner bearing sleeve 107 is connected rigidly with the arm 101. The outer bearing sleeve 106 is supported through two needle bearings 108~ 109 so as to be able to rotate on the inner bearing sleeve 107, which means that the arms 101, 102 can rotate relative to each other.
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201~ 9 The needle bearing 108 rests on one side on an extension 110 of the inner bearing sleeve 107 and on the other side on a safety ring 111 that is arranged within the outer bearing sleeve 106. The needle bearing 109 rests on one side on a safety ring 112 that is arranged within the inner bearing sleeve 107 and at the other end on a bearing plate 113 that is bolted to the arm 102.
A continuous shaft 115 is supported in two bearing sleeves 114 in the inner bearing sleeve 107. A notched-belt pulley 116 and immediately adjacent thereto a pinion 117 are secured on the end of the shaft 115 that extends into the arm 101;
this pinion rests at its side on the inner side of the arm 101. On the other end of the shaft 115 that extends into the arm 102 there is a notched-belt pulley 118 that is adjacent to the bearing plate 113 at the side. The notched-belt pulleys 116, 118 that are secured to the shaft 115, and the pinion 117 form an axially acting mounting for the arms 101, 102.
,, The pinion 117 engages with the pinion 119 that is secured on a shaft that floats in the arm 101. In addition, a notched-belt pulley 122 is secured to the shaft 120 and a notched belt 123 passes over this. The notched belt 123 also passes over a ~otched-belt pulley 124 that is secured at the end of a shaft 125. The shaft 125 i's accommodated in a bearing sleeve 126 that is secured to the arm 101 and supports at its other end a pressure roller 127 that is rigidly connected to this. The components 117, 119 to 124 together form a first gearing system 128 that can be reversed.
A notched belt 129 runs over the notched-belt pulley 118 and also passes over a notched-belt pulley 131 secured to the end of a shaft 130. The shaft 130 is accommodated in a bearing sleeve 132 that is secured on the arm 102 and supports at its other end a pressure roller 133 that is connected rigidly to . . .
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it. The components 118, 129 and 131 together form a second gearing system 131 that runs in one direction only.
A pressure element 135 is secured on the end area of the arm 101 that is opposite the pressure roller 127 and this is a component part of a pressing mechanism 136 that is described in greater detail below. A known geared motor 137 is secured to the arm 101 and this extends within the pressure element 135 without, however, coming into contact with this. The geared motor 137 consists of a motor section 138 and an epicyclic gear train 139 that is flanged onto the side thereof. The epicyclic gear train 139 incorporates a shaft 140 that forms the output of the gearing system.
A notched-belt pulley 141 is secured to the shaft 140 and a notched belt 142 passes over this. The notched belt 142 also passes over the notched-belt pulley 116 described heretofore.
The components 116, 141, and 142 together form a gear system 143 that forms a positive drive connection between the output of the epicyclic gear train 139 and the shaft 115.
A pressure arm 144 is clamped onto the pressure element 135 so as to be unable to rotate independently thereof, and as is shown in figure 3. This consists of a slotted adaptor sleeve 145, an arm 146 of rectangular cross-section, which extends above the arm 102 and parall~l thereto, and an extension 147 that extends transversely to this.
:`, A narrow supporting plate 148 is secured on the end of the arm 102 that is opposite the pressure roller 133. A threaded spindle 150 is arranged so as to be able to pivot on the supporting plate 148 with the help of a collar screw 149, and this threaded spindle passes through a drilled hole 151 (figure 3) in the extension 147. In that part of the threaded spindle 150 that is above the extension 147 there are a handle 152 and a plurality of disk springs 153, that rest through the medium of a washer 154 on the extension 147.
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20024~9 The components 150, 152, 153, and 154 together form a spring mechanism 155.
A stop washer 156 that can be adjusted for height and which - incorporates an inside thread is arranged on the threaded spindle 150 beneath the extension 147.
A bracket 157 that is of U-shaped cross section is secured to the arm 102 and the arm 146 extends into this. A shaft 159 is supported in the bracket 157 above a flat extension piece 158 of the arm 146; at one end, this shaft 159 incorporates a collar 160 and at the other a clamping ring 161. An eccentric 162 is secured to the shaft 159 and this acts in conjunction with an extension piece 158 of the arm 146. In addition to the eccentric 162, an operating lever 163 is also mounted on the shaft 159 so as to be able to rotate. A pin 164 that extends to the side in the direction of the eccentric 162 is arranged within the operating lever 163.
Within the eccentric 162 there is a plurality of drilled holes 165, the diameter and distance from the shaft 159 of i which are so dimensioned that the pins 164 can fit into them.
A compression spring 166 that is arranged on the shaft 159 : holds the operating lever 163 in contact against the eccentric 162. The pin 164, the drillings 165, and the compression spring 166 together form a releasable coupling.
Within the console 157, abové the eccentric 162, there is a cut- out 167 that makes it possible for the operating lever 163 to be pivoted in a position that extends perpendicular to the arm 102. The components 159 to 166 together form an adjusting mechanism 168.
An electrirally heated heating wedge 170 is arranged on the arm 102 with the help of a parallel toggle lever 169 that can be moved by a handle 171 that is connected to the parallel toggle lever 169, back and forth between a rest position that is at a distance from the pressure rollers 127, 133 and into ! ' `' " ' ' , ~; . ~ . ~ ' ' ' '. ~' ' . ' .
200Z4~9 a working position, shown in figure 1, that is close to the pressure rollers 127, 133.
The welding apparatus is used to produce overlapping seams in plastic foils, this being done, in particular, when lining tunnels in which the welded seams are mainly made in a vertical plane and overhead.
The welding apparatus is so arranged between the plastic foils that are to be joined together that one plastic foil runs beneath the bridge piece 103 and the heating wedge 170 and the other plastic foil runs above the bridge piece 103 and the heating wedge 170, and at the same time they lie directly one on top of the other between the pressure rollers 127, 133.
The welding pressure between the pressure rollers 127, 133 that is required to execute the welding process is effected by means of the pressing mechanism 136.
The level of the welding pressure is adjusted with the help of the handle 152. By rotating the handle 152 downwards the disk springs 153 are pressed more strongly against the extension 147 which means that the pressure element 133 is pressed downwards. The contact pressure that acts on the pressure element 135 means tnat a turning moment in a clockwise direction, as in figure 2, is exerted on the arm 101. Because of this turning moment, the arm, as in figure 2, is pivoted in a clockwise direction, whereby the pressure roller 127 being pressed downwards against the pressure roller 133 thereby.
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Because of the stop washer 156, the common angle subtended between the arms 101, 102 that are in the welding position can be limited, i.e., the arms or the pressure rollers 127, 133 cannot be moved further towards each other if the ~ xtension is lying on the stop washer 156. In this way, the ;
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, : " ' 20024~9 thickness of the welded seam that is to be produced can be : adjusted within very precise limits.
Using the adjusting mechanism 168, the arms 101, 102 can be moved away from each other, whereupon two new foils can be introduced between the pressure rollers 127, 133 without any problem. To this end, the operating lever 163 is moved upwards from the position that is shown in figure 2. The eccentric 162 that is thus rotated by the pin 164 tilts the arm 146 in a counter- clockwise direction, whereupon the extension 147 of the pressure arm 144 rests against the stop washer 156. Since the pressure element 135 and the pressure arm 144 are connected rigidly to each other, and thereby form a continuous pressure beam 172, the adjusting movement that comes from the adjusting mechanism 168 ensures that the pressure beam 172, which in this case acts as a supporting two-arm lever, is pivoted as a whole about the stop washer 156 that now acts as a pivot axis. The pivoting movement leads to an elastic deformation of the pressure element 135 that is connected rigidly with the arm 101, whereby a turning moment is exerted on the arm 101. As soon as this turning moment is stronger than the turning moment generated by the spring mechanism 155 in the opposite direction, the arm 101, as in figure 2, is pivoted in a counter-clockwise direction, whereby the pressure roller 127 is moved away from the pressure roller 133.
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DE-GM 83 01 191 describes a welding apparatus with an essentially U-shaped housing, in which at the ends of the two housing arms that lie in different planes, and the angular position of which can be varied relative to each other, there is an over-hung pressure roller. Each of the pressure ; rollers is connected through an appropriate gearing system to a dedicated motor or to a releasable coupling through a common motor. The welding apparatus incorporates two pairs of rollers to support the lower of the two plastic foils that are to be welded together or the base or sublayer.
DE-OS 35 35 760 describes another mobile welding apparatus with an essentially U-shaped housing, from which the rollers have been eliminated in order to save weight. In this welding apparatus, each of the pressure rollers that is arranged at the end of each housing arm has a dedicated motor and a dedicated reduction gearing. The motors and the gearing are arranged coaxially to the appropriate pressure rollers. Since the motors project from the sides of the housing arms, this particular welding apparatus is bulky and awkward.
It is an object of the present invention to provide a mobile apparatus for welding plastic foils, which not only weighs as little as possible but is also of compact construction and particularly convenient to use.
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20(~2419 According to the present invention there i5 provided in an apparatus for welding plastic foils comprising a substantially U-shaped housing formed from two arms, a bridge piece joining said arms together, said being rotatable relative to each other about the longitudinal axis of the bridge piece, a powered pressure roller arranged on each of the free ends of each arm, a pressing mechanism for urging the pressure rollers together, and a heating element, the improvement wherein a geared motor is arranged on the bridge piece to drive both of the pressure rollers, said motor having two opposing outputs which drive the two pressure rollers in opposite directions through a gear system.
Because of the fact that a geared motor that is used to drive the pressure rollers and which has two opposing outputs that are each connected through gears to the associated pressure roller is arranged on the cross-piece of the U-shaped housing, it has been possible, on the one hand, to reduce the weight of the apparatus by eliminating one motor and, on the other, to arrive at a more compact construction by eliminating parts that project beyond the sides of the housing. As a consequence of these two advantageous characteristics, the welding apparatus configured according to the present invention is particularly suitable for the production of tunnel linings, in which, when welding is being carried out on vertical walls or overhead, the whole weight of the welding apparatus has to be borne by one operator.
The use of a single motor for both pressure rollers entails the added advantage that the pressure rollers always run synchronously with each other.
An even more compact construction can be achieved by arranging the geared motor within the tubular bridge piece that is closed in around its periphery, which entails the additional advantage that the geared motor is encapsulated and th~s protected against dirt and damage.
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20024~9 If the drive motor for the pressure rollers is arranged within a tubular pressure element of the pressing mechanism at a distance from and parallel to the bridge piece of the U-shaped housing and the drive motion of the motor to the two geax systems that are connected with the pressure rollers is split with the help of a shaft that is supported within the bridge piece, it is possible to use a geared motor with only one output as the drive motor. A geared motor that has only one output is narrower by the length of the gearing that has been eliminated, which makes it possible to make the housing of the apparatus, i.e., the bridge piece and the pressure element correspondingly narrower. Even though the saving in weight brought about by the elimination of one gear system for the geared motor may be balanced out by the shaft in the bridge piece that is now required and the additional gearing that connects the shaft with the geared motor, the reduction in the length of the bridge piece, of the pressure element, and of the bearings for the pressure rollers will result in a further and perceptible reduction in weight of the whole system.
However, of even greater signi~icance is the advantage that because of the reduction in the weight of the housing the apparatus can be made much narrower and thus, overall, more compact and consequently considerably more convenient.
By making the operating lever adjustable into a position that is essentially parallel to the housing arm that supports it, once the arms have been moved into the working position, it is also possible to arrive at a comparatively flat construction for the apparatus.
The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a plan view of the welding apparatus;
Figure 2 is a cross sectional drawing taken on the line II-II
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in figure l;
Figure 3 is a cross section taken on the line III-III in figure l;
Figure 4 is a plan view of the welding apparatus of a second embodiment;
Figure 5 is a further view of the welding apparatus;
Figure 6 is a side view of the welding apparatus;
Figure 7 is a sectionized plan view of the welding apparatus in a third embodiment;
Figure 8 is a partially cross-sectioned side view of the welding apparatus;
Figure 9 is a side view of the pressure arm clamped onto the pressure element; and Figure 10 is a cross sectional view of the adjusting . 15 mechanism for the pressure arm, taken on the line IV-IV in : figure 2.
The welding apparatus shown in figures l to 3 has an essentially U-shaped housing 1 that consists of two arms 2 and 3 and of a bridge piece 4 that connects these arms with each other. The arms 2, 3 are hollow and each has a removeable side wall 5, 6.
The bridge piece 4 is formed from two bearing sleeves 7, 8 that can telescope into each other, of which the outer bearing sleeve 7 is rigidly c'onnected to the arm 2 and the inner bearing sleeve 8 is rigidly connected to the arm 3.
The inner bearing sleeve 8 consists of an annular part 9, a pipe section lO and an extended hub 11, these parts being connected rigidly to each other by welds. The hub 11 incorporates a flange 12, a base part 13 with relatively thicker walls, and an extension 14. At the end of the outer bearing sleeve 7 there is a stepped extension 15, and at the other end there is a cylindrical extension 16.
- The extension 16 of the outer bearing sleeve 7 lies on the ; hub 11 and together with this forms a bearing 17. A ball : , . .
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200~9 bearing 18 is arranged on the extension 14 of the hub 11 and the extension 15 of the outer bearing sleeve 7 rests on this.
The two bearing sleeves 7 and 8 are supported on each other so as to be able to rotate through the bearings 17 and 18, whic:h means that the arms 2 and 3 can also be rotated relative to each other.
Within the bearing sleeve 8 there is a known geared motor 19 that consists of a centrally arranged motor section 20 and two epicyclic gears 21, 22 that are installed outside. Each epicyclic gear 21, 22 has an output shaft 23 or 24, respectively. The geared motor 19 is connected ta the inner bearing sleeve 8 through the bearing plate 25 so as to be unable to rotate independently of this, in that the epicyclic gear 22 is bolted up with the bearing plate 25 and this is bolted up with the annular part 9. The other end of the gear motor 19 is supported in a bearing plate 26 that is bolted up with the epicyclic gearing 21 and rests with one section (not described in greatsr detail herein) on the extension 14 of the hub 11 so as to be radially supported. A shoulder 27 of 20 the bearing plate 26 presses against the inner ring of the ball bearing 18 and thus holds the outer ring of the ball ; bearing 18 in contact with a shoulder of the extension 15 of the outer bearing sleeve 7 and, on the other hand, acts as a contact surface for the face of the extension 16 on the flange 12.
A notched-belt pulley 28 is secured to the shaft 23 and a notched belt 29 passes over a notched-belt pulley 30 that is secured on a shaft 31 that floats in the arm 2. A pinion 32 is secured to the shaft 31 and this engages with a similarly floating shaft 33. A notched-belt pulley 35 is secured to the shaft 33~ The notched belt 36 also passes over the notched-belt pulley 37 that is secured to one end of a shaft 38. The shaft 38 is accommodated in a bearing sleeve 39 that is secured to the arm 2 and supports at its other end a : . -., ., , , . ,~ .
.
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., ~9 pressure roller 40 that is rigidly secured to this. The two pinLons 32, 34 form a reversing gear 41.
A notched-belt pulley 42 is secured to the shaft 24 and a notched belt 43 runs around this. The notched belt 43 also passes over a notched-belt pulley 44 that is secured to the end of a shaft 45. The shaft 45 is accommodated in a bearing sleeve 47 that is secured on the arm 3 and supports at its other end a pressure roller 47 that is connected rigidly to it.
An electrically heated heating wedge 49 is arranged on the arm 3 with the help of a parallel crank mechanism 48 that can be moved back and forth between the retracted rest position shown in figure 1 and a working position that is tight against the pressure rollers 40, 47, by means of a handle 50 that is connected to the parallel crank mechanism 48.
Two spring rods 51 that are parallel to each other are secured in the base part 13 of the hub 11 and these extend through an opening 52 in the outer bearing sleeve 7 and extend essentially along the arm 2. The two spring rods 51 are enclosed by two opposing double profile rollers 53, 54 that are so supported on a first supporting plate 55 as to be freely rotatable. The first supporting plate 55 is arranged so as to be adjustable on a second supporting plate 58, transversely to the longitudinal axis of the spring rods 51, this being done with the help of vertical slots 56 and corresponding screws 57. The second carrier plate 58 is arranged so as to be adjustable on a retaining plate 61, parallel to the longitudinal axis of the spring rods 51 with the help of horizontal slots 59 and corresponding screws 60.
The retaining plate 61 is arranged rigidly on the arm 2 through an interposed piece 62, which means that the carrier plate 58 can be moved on the retaining plate 61 by one or more multiples of the distance between the drilled holes.
The components 51 to 62 form a pressing mechanism 64.
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200241~
Runners 65, 66 that are triangular and rounded off at the prolecting tip are arranged on the ends of the arms 2 and 3 tha~ are ad;acent to the bridge piece 4.
The method of operation of the welding apparatus will now be described.
The welding apparatus is used to produce overlapping seams in plastic foils, this being done particularly when lining tunnels in which the welded seams are to be made mainly in a vertical plane and overhead.
The welding apparatus is so arranged between the plastic foils that are to be welded together that one plastic foil runs beneath the bridge piece 4 and the heating wedge 49 and the other plastic foil runs above the bridge piece 4 and the heating wedge 49, so that they lie directly one on top of the other between the pressure rollers 40, 47.
The welding pressure between the pressure rollers 40, 47, which is required to complete the welding procedure, is generated by the pressing mechanism 64. When the two supporting plates 55, 58 are appropriately adjusted the two spring rods 51 shown in figure 2 are tensioned downwards by the upper double profile roller 53, when a turning moment is exerted on the base part 13 that supports the spring rods 51 and thus on the inner bearing sleeve 8 and the arm 3 that is connected with it, which means that the uppermost pressure roller 47 is pressed against the pressure roller 40 that is located beneath it.
The pressing mechanism 64 can accommodate two basic adjustments, namely, on the one hand, the magnitude of the initial stressing force and on the other hand, the degree of the springing effect of the spring rods 51. The initial stressing force is adiusted by moving the supporting plate 55 transversely to the longitudinal axis of the spring rods 51.
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;~)Z4~9 The stiffness of the springing action of the spring rods 51 can be adjusted by moving or displacing the supporting plate 58 parallel to the longitudinal axis of the spring rods 51, when the effective length of the spring rods 51 is changed.
Thus, optimal operating conditions can be adjusted for specific foil materials and foil thicknesses by the two , different adjusting possibilities of the pressing mechanism ? 64. So, for example, when welding HDPE foils, it is necessary to use relatively high pressure. At the same time, in addition to the initial stressing it is also desirable to have a very stiff spring action so that when welding is being done on a construction site, dirt such as grains of sand and small stones which could accidentally get between the foils are pressed into the softened foil so that the necessary welding pressure can be maintained at these points as well.
In contrast to this, insofar as larger transition points such as, for instance, transverse seams, are to be crossed during the welding process, the springs are set for a high degree of initial stressing in order that the initial stressing force ' 20 does not have to be reduced when negotiating these cross-over points.
; Should a particularly low welding pressure be required, then work can be carried out using only one spring rod 51. In contrast to this, if extremely high welding pressure is required, then spring rods of a greater cross section can be used.
Since the whole pressing mechanism 64 as shown in figure 2 does not extend beyond the upper and lower sides of the arm 2 that supports it, the overall welding apparatus is kept very compact and convenient.
Once the welding pressure has been adjusted, the heating wedge 49 that has been heated to the required welding temperature is moved into the welding position. As soon as :
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20~ 9 this heating wadge 49 reaches the required welding position, the geared motor 19 is switched on, whereupon the welding apparatus moves relative to the foil with the help of the driven pressure rollers 40, 47, whereupon the softened areas of foil are bonded to each other so as to form a welded seam.
The welding apparatus that is shown in figures 4 to 6 is identical to the welding apparatus described in the first embodiment as far as the housing and the drive systems are concerned. The essentially U-shaped housing 1 also consists of the two arms 2, 3 as well as the bridge piece 4 that hinges these together and in which the geared motor for the pressure rollers 40, 47 (not shown in this instance) is arranged. The welding apparatus also has a heating wedge 49 that is mounted on a parallel crank mechanism 48. Further, triangular runners 65, 66 that are rounded over at the projecting tips are secured to the adjacent ends of the arms 2, 3.
; In contrast to this, the pressing mechanism 80 that is used to generate the welding pressure is of a completely different construction to the pressing mechanism 64 used in the first embodiment. The pressing mechanism 80 incorporates a rod-like pressure element 81 that is secured to the runner 65 of the arm 2 and this extends parallel to the bridge piece 4, at a distance thereto, parallel to its longitudinal axis. An angle piece 82 is secured to the unattached end of the pressure element 81 and this incorporates an L-shaped horizontal angle plate 82a. The pressure element 81 and the angle piece 82 together form a pressure beam 83. A threaded spindle 85 is secured within a rotary piece 84 that is accommodated in the runner 66 and this spindle extends through a drilled hole 86 in the runner 66 and through a drilled hole (not shown herein) in the plate 82a. Within the part of the threaded spindle 85 that is above the plate 82a there is a handle 87 and a plurality of disk springs 88 that rest on the plate 82 through the medium of a washer 89. The '.
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zo~9 components 85, 87, 88, and 89 together form a spring mechanism 90. A stop washer 91 that has a corresponding internal thread, and which can be adjusted for height, is arranged beneath the plate 82a on the threaded spindle 85.
On the arm 3 there is an angle bracket 92 on which a handle 93 or 94 that extends transversely to the arms 2, 3 is secured. A rod 95 that can be moved longitudinally is accommodated in the angle bracket 92 and the lower end of this supports a pressure piece 96 and is also connected with 10 a toggle joint system that incorporates a handle 97. The components 92 and 95 to 98 together form an adjusting mechanism 99.
Up to the point of adjustment of the welding pressure, the remaining functions of the welding apparatus are the same as in the welding apparatus described in the first embodiment, so there is no need for a more detailed description of these.
The level of the welding pressure is adjusted with the help of the handle 87. Turning the handle 87 down presses the disk springs 88 more strongly against the plate 82a and thus press the pressure beam 83 downwards as a whole. The pressure that acts on the pressure beam 83 causes a turning moment that acts in a clockwise direction as in figure 6 to be exerted on the runner 65. Because of this turning moment, the arm 2 is pivoted in a clock~ise direction as shown in figure 6, which means that the pressure roller 40 is pressed upwards against the pressure roller 47.
The overall angle between the àrms 2, 3 that are in the welding position can be limited by means of the stop washer 91, i.e., the arms or the pressure rollers 40, 47 cannot be moved further towards each other if the angle plate 82 is resting on the stop washer 91. In this way, it is possible to adjust the thickness of the welding seam within very precise limits.
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2~ 9 The arms 2, 3 can be moved apart with the help of the adjusting mechanism 99, whereupon two new foils can be introduced without any problem between the pressure rollers 40, 47. To this end, the handle 97 is swung downwards and thus the rod 95 is also moved downward. In the course of this movement, the pressure piece 96 comes into contact with the angle plate 82 that is resting on the stop washer 91 and causes the pressure beam 83, which acts in this case as a two-arm lever, to be pivoted as a whole about the stop washer 91 that now acts as a pivot axis, this pivoting movement, as shown in figure 4, taking place in a counter-clockwise direction. The pivoting movement leads to an elastic deflection of the pressure element 81 that is connected rigidly to the runner 65, whereupon a turning movement that acts in a counter-clockwise direction as in figure 6 is exerted on the runner 65 which together with the arm 2 can be pivoted about the longitudinal axis of the bridge piece 4.
As soon as this turning movement is stronger than the turning movement that is generated by the spring mechanism 90 in the opposite direction, the arm as in figure 6 is pivoted counter-clockwise, whereupon the prçssure roller 40 is moved away from the pressure roller 47.
The welding apparatus of the third embodiment has an essentially U-shaped housing 100 that consists of two arms - 25 101, 102 as well as a bridge piece 103 that joins these with each other. The arms 101, 102 are hollow and each has a removeable side wall 104, 105.
The bridge piece 103 is formed from two bearing sleeves 106, - 107 that can telescope into each other, of which the outer io bearing sleeve 106 is connected with the arm 102 and the inner bearing sleeve 107 is connected rigidly with the arm 101. The outer bearing sleeve 106 is supported through two needle bearings 108~ 109 so as to be able to rotate on the inner bearing sleeve 107, which means that the arms 101, 102 can rotate relative to each other.
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201~ 9 The needle bearing 108 rests on one side on an extension 110 of the inner bearing sleeve 107 and on the other side on a safety ring 111 that is arranged within the outer bearing sleeve 106. The needle bearing 109 rests on one side on a safety ring 112 that is arranged within the inner bearing sleeve 107 and at the other end on a bearing plate 113 that is bolted to the arm 102.
A continuous shaft 115 is supported in two bearing sleeves 114 in the inner bearing sleeve 107. A notched-belt pulley 116 and immediately adjacent thereto a pinion 117 are secured on the end of the shaft 115 that extends into the arm 101;
this pinion rests at its side on the inner side of the arm 101. On the other end of the shaft 115 that extends into the arm 102 there is a notched-belt pulley 118 that is adjacent to the bearing plate 113 at the side. The notched-belt pulleys 116, 118 that are secured to the shaft 115, and the pinion 117 form an axially acting mounting for the arms 101, 102.
,, The pinion 117 engages with the pinion 119 that is secured on a shaft that floats in the arm 101. In addition, a notched-belt pulley 122 is secured to the shaft 120 and a notched belt 123 passes over this. The notched belt 123 also passes over a ~otched-belt pulley 124 that is secured at the end of a shaft 125. The shaft 125 i's accommodated in a bearing sleeve 126 that is secured to the arm 101 and supports at its other end a pressure roller 127 that is rigidly connected to this. The components 117, 119 to 124 together form a first gearing system 128 that can be reversed.
A notched belt 129 runs over the notched-belt pulley 118 and also passes over a notched-belt pulley 131 secured to the end of a shaft 130. The shaft 130 is accommodated in a bearing sleeve 132 that is secured on the arm 102 and supports at its other end a pressure roller 133 that is connected rigidly to . . .
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it. The components 118, 129 and 131 together form a second gearing system 131 that runs in one direction only.
A pressure element 135 is secured on the end area of the arm 101 that is opposite the pressure roller 127 and this is a component part of a pressing mechanism 136 that is described in greater detail below. A known geared motor 137 is secured to the arm 101 and this extends within the pressure element 135 without, however, coming into contact with this. The geared motor 137 consists of a motor section 138 and an epicyclic gear train 139 that is flanged onto the side thereof. The epicyclic gear train 139 incorporates a shaft 140 that forms the output of the gearing system.
A notched-belt pulley 141 is secured to the shaft 140 and a notched belt 142 passes over this. The notched belt 142 also passes over the notched-belt pulley 116 described heretofore.
The components 116, 141, and 142 together form a gear system 143 that forms a positive drive connection between the output of the epicyclic gear train 139 and the shaft 115.
A pressure arm 144 is clamped onto the pressure element 135 so as to be unable to rotate independently thereof, and as is shown in figure 3. This consists of a slotted adaptor sleeve 145, an arm 146 of rectangular cross-section, which extends above the arm 102 and parall~l thereto, and an extension 147 that extends transversely to this.
:`, A narrow supporting plate 148 is secured on the end of the arm 102 that is opposite the pressure roller 133. A threaded spindle 150 is arranged so as to be able to pivot on the supporting plate 148 with the help of a collar screw 149, and this threaded spindle passes through a drilled hole 151 (figure 3) in the extension 147. In that part of the threaded spindle 150 that is above the extension 147 there are a handle 152 and a plurality of disk springs 153, that rest through the medium of a washer 154 on the extension 147.
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20024~9 The components 150, 152, 153, and 154 together form a spring mechanism 155.
A stop washer 156 that can be adjusted for height and which - incorporates an inside thread is arranged on the threaded spindle 150 beneath the extension 147.
A bracket 157 that is of U-shaped cross section is secured to the arm 102 and the arm 146 extends into this. A shaft 159 is supported in the bracket 157 above a flat extension piece 158 of the arm 146; at one end, this shaft 159 incorporates a collar 160 and at the other a clamping ring 161. An eccentric 162 is secured to the shaft 159 and this acts in conjunction with an extension piece 158 of the arm 146. In addition to the eccentric 162, an operating lever 163 is also mounted on the shaft 159 so as to be able to rotate. A pin 164 that extends to the side in the direction of the eccentric 162 is arranged within the operating lever 163.
Within the eccentric 162 there is a plurality of drilled holes 165, the diameter and distance from the shaft 159 of i which are so dimensioned that the pins 164 can fit into them.
A compression spring 166 that is arranged on the shaft 159 : holds the operating lever 163 in contact against the eccentric 162. The pin 164, the drillings 165, and the compression spring 166 together form a releasable coupling.
Within the console 157, abové the eccentric 162, there is a cut- out 167 that makes it possible for the operating lever 163 to be pivoted in a position that extends perpendicular to the arm 102. The components 159 to 166 together form an adjusting mechanism 168.
An electrirally heated heating wedge 170 is arranged on the arm 102 with the help of a parallel toggle lever 169 that can be moved by a handle 171 that is connected to the parallel toggle lever 169, back and forth between a rest position that is at a distance from the pressure rollers 127, 133 and into ! ' `' " ' ' , ~; . ~ . ~ ' ' ' '. ~' ' . ' .
200Z4~9 a working position, shown in figure 1, that is close to the pressure rollers 127, 133.
The welding apparatus is used to produce overlapping seams in plastic foils, this being done, in particular, when lining tunnels in which the welded seams are mainly made in a vertical plane and overhead.
The welding apparatus is so arranged between the plastic foils that are to be joined together that one plastic foil runs beneath the bridge piece 103 and the heating wedge 170 and the other plastic foil runs above the bridge piece 103 and the heating wedge 170, and at the same time they lie directly one on top of the other between the pressure rollers 127, 133.
The welding pressure between the pressure rollers 127, 133 that is required to execute the welding process is effected by means of the pressing mechanism 136.
The level of the welding pressure is adjusted with the help of the handle 152. By rotating the handle 152 downwards the disk springs 153 are pressed more strongly against the extension 147 which means that the pressure element 133 is pressed downwards. The contact pressure that acts on the pressure element 135 means tnat a turning moment in a clockwise direction, as in figure 2, is exerted on the arm 101. Because of this turning moment, the arm, as in figure 2, is pivoted in a clockwise direction, whereby the pressure roller 127 being pressed downwards against the pressure roller 133 thereby.
,~
Because of the stop washer 156, the common angle subtended between the arms 101, 102 that are in the welding position can be limited, i.e., the arms or the pressure rollers 127, 133 cannot be moved further towards each other if the ~ xtension is lying on the stop washer 156. In this way, the ;
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, : " ' 20024~9 thickness of the welded seam that is to be produced can be : adjusted within very precise limits.
Using the adjusting mechanism 168, the arms 101, 102 can be moved away from each other, whereupon two new foils can be introduced between the pressure rollers 127, 133 without any problem. To this end, the operating lever 163 is moved upwards from the position that is shown in figure 2. The eccentric 162 that is thus rotated by the pin 164 tilts the arm 146 in a counter- clockwise direction, whereupon the extension 147 of the pressure arm 144 rests against the stop washer 156. Since the pressure element 135 and the pressure arm 144 are connected rigidly to each other, and thereby form a continuous pressure beam 172, the adjusting movement that comes from the adjusting mechanism 168 ensures that the pressure beam 172, which in this case acts as a supporting two-arm lever, is pivoted as a whole about the stop washer 156 that now acts as a pivot axis. The pivoting movement leads to an elastic deformation of the pressure element 135 that is connected rigidly with the arm 101, whereby a turning moment is exerted on the arm 101. As soon as this turning moment is stronger than the turning moment generated by the spring mechanism 155 in the opposite direction, the arm 101, as in figure 2, is pivoted in a counter-clockwise direction, whereby the pressure roller 127 is moved away from the pressure roller 133.
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Claims (12)
1. In an apparatus for welding plastic foils comprising a substantially U-shaped housing formed from two arms, a bridge piece joining said arms together, said being rotatable relative to each other about the longitudinal axis of the bridge piece, a powered pressure roller arranged on each of the free ends of each arm, a pressing mechanism for urging the pressure rollers together, and a heating element, the improvement wherein a geared motor is arranged on the bridge piece to drive both of the pressure rollers, said motor having two opposing outputs which drive the two pressure rollers in opposite directions through a gear system.
2. An apparatus as claimed in claim 1, wherein the geared motor is arranged within the bridge piece, which is tubular and closed off around its periphery.
3. An apparatus as claimed in claim 2, wherein the bridge piece consists of two bearing sleeves that are each connected rigidly to one of the two arms and which telescope into each other, the inner bearing sleeve being connected with the gear motor so as to be unable to rotate independently thereof.
4. An apparatus as claimed in claim 3, wherein the inner bearing sleeve extends over the whole length of the gear motor and the outer bearing sleeve extends at least as far as the centre of the inner bearing sleeve; and the two bearing sleeves are supported on one another through two bearings, the intervening distance corresponding essentially to the length of the outer bearing sleeve.
5. An apparatus as claimed in claim 4, wherein the inner bearing sleeve serves as a carrier for at least one moveable spring rod of a pressing mechanism that extends through an opening of the outer bearing sleeve and extends essentially parallel to the arm that can be moved relative to the gear motor, said pressing incorporating a pressure piece that acts in conjunction with the spring rod and is arranged on the arm.
6. An apparatus as claimed in claim 5, wherein the pressure piece comprises at least one roller that rests on the spring rod, that can be adjusted to change the effective length of the spring rod along the arm that supports it and transversely to the arm in order to change the initial stressing of the spring rod.
7. An apparatus as claimed in claim 1, wherein one of the arms serves as a mounting for a pressure element that is arranged at a distance from the bridge piece parallel to the longitudinal axis thereof, this being a component part of a pressure beam of a pressing mechanism; and the pressure beam is acted upon by a spring mechanism that is mounted on the other arm so as to be adjustable.
8. An apparatus as claimed in claim 7, wherein a stop element is arranged on the side of the pressure beam that is opposite the spring mechanism; and an adjusting mechanism is associated with the free end of the pressure beam that pivots it about the stop element.
9. An apparatus as claimed in claim 8, wherein the stop element to limit the angle of rotation of the arms in the working position is adjustable.
10. An apparatus for welding plastic foils comprising an essentially U-shaped housing that is formed from two arms and a bridge piece that connects the arms together, the arms being pivotable relative to each other about the longitudinal axis of the bridge piece, a pressure roller arranged at each of the free ends of each arm, a pressure mechanism that incorporates a rod-like pressure element arranged on one of the arms spaced from the bridge piece, essentially parallel to the longitudinal axis thereof, a spring mechanism that acts in conjunction with the bridge piece and that rests on the other arm, and a heating element, there being a geared motor arranged on the housing so as to drive both pressure rollers, said motor being connected through a first reversing gearing system and a second gear system that rotates in a constant direction with the pressure roller associated therewith, wherein the pressure element is tubular, the geared motor that incorporates only one output is arranged within the pressure element and the output shaft of the geared motor is connected through an additional gearing system and a shaft that is supported within the bridge piece with the first and second gearing systems.
11. An apparatus as claimed in claim 10, wherein the pressure element supports a transverse pressure arm incapable of rotating independently thereof, said arm resting on a stop element of the spring mechanism and extending above the arm of the housing that is not connected with the pressure element, and an adjusting mechanism consisting of a rotatable eccentric and an operating lever is associated with the free end of the pressure arm.
12. An apparatus as claimed in claim 11, wherein the operating lever is connected through a releasable coupling, which incorporates a plurality of adjustments, with said eccentric.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3837869.8 | 1988-11-08 | ||
| DE3837869A DE3837869C1 (en) | 1988-11-08 | 1988-11-08 | Apparatus for welding plastics films |
| DEP3921711.6 | 1989-07-01 | ||
| DE3921711A DE3921711C1 (en) | 1988-11-08 | 1989-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2002419A1 true CA2002419A1 (en) | 1990-05-08 |
Family
ID=25874029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002002419A Abandoned CA2002419A1 (en) | 1988-11-08 | 1989-11-07 | Apparatus for welding plastic foils |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0442919B1 (en) |
| JP (1) | JP2582448B2 (en) |
| CA (1) | CA2002419A1 (en) |
| DE (1) | DE3921711C1 (en) |
| WO (1) | WO1990005060A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PT1464471E (en) * | 2003-04-04 | 2006-12-29 | Leister Process Tech | Process and apparatus for overlapping joining of flat plastic materials |
| EP3028836B1 (en) * | 2014-12-04 | 2017-11-01 | Leister Technologies AG | Welding machine for connecting of overlapping sheets of material |
| EP4008527B1 (en) * | 2020-12-07 | 2024-06-26 | Herz Austria Gesellschaft m.b.H | Use of a welding device |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NO144732C (en) * | 1976-01-30 | 1981-10-28 | Sarna Kunststoff Ag | WELDING APPLIANCES FOR ARTICLES. |
| AT359277B (en) * | 1978-07-20 | 1980-10-27 | Winkler Werner | WELDING DEVICE FOR RAILWAYS OR TILES FROM THERMOPLASTIC PLASTIC |
| AT381274B (en) * | 1984-10-04 | 1986-09-25 | Neumueller Walter Dkfm Ing | WELDING MACHINE |
| AT381276B (en) * | 1984-11-13 | 1986-09-25 | Neumueller Walter | WELDING MACHINE |
| DE3617642A1 (en) * | 1985-10-12 | 1987-04-16 | Pfaff Ind Masch | Welding device for film webs |
-
1989
- 1989-07-01 DE DE3921711A patent/DE3921711C1/de not_active Expired - Lifetime
- 1989-10-25 EP EP89912242A patent/EP0442919B1/en not_active Expired - Lifetime
- 1989-10-25 WO PCT/EP1989/001271 patent/WO1990005060A1/en active IP Right Grant
- 1989-10-25 JP JP1511361A patent/JP2582448B2/en not_active Expired - Lifetime
- 1989-11-07 CA CA002002419A patent/CA2002419A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04505730A (en) | 1992-10-08 |
| WO1990005060A1 (en) | 1990-05-17 |
| DE3921711C1 (en) | 1990-03-29 |
| EP0442919B1 (en) | 1993-04-07 |
| EP0442919A1 (en) | 1991-08-28 |
| JP2582448B2 (en) | 1997-02-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |