Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – With separate heating means for work
Reexamination Certificate
1999-03-24
2001-06-12
Mayes, Curtis (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
With separate heating means for work
C156S580000
Reexamination Certificate
active
06244320
ABSTRACT:
SUMMARY OF THE INVENTION
The present invention concerns heating plate welding machines, which are generally used to weld together two heat-weldable material parts along respective plane or non-plane connecting surfaces.
In the heating plate welding machines usually employed, such as that described in document FR 2 320 839 A, for example, a frame carries the various functional units of the machine including a heating plate, a first workpiece support device, and a second workpiece support device facing the first workpiece support device. First means move the heating plate along a transverse insertion travel parallel to its plane between a welding position engaged between the first and second workpiece support devices and a loading position withdrawn from the first and second workpiece support devices. Second means move the heating plate along a welding travel perpendicular to its plane between two extreme positions. The first workpiece support device is fixed to the frame. The second workpiece support device is mobile, and can be moved by third means along a contact travel perpendicular to the plane of the heating plate between the extreme positions and toward or away from the first workpiece support device. The machine also includes cylinders for moving the first workpiece support device toward or away from the second workpiece support device.
The movements of the heating plate, along the insertion travel and along the welding travel, are generally linear and driven by cylinders which provide amplitudes of movement limited by the allowed overall size of the cylinders of the machine. Similarly, the second workpiece support device is moved along the contact travel by a cylinder providing a limited amplitude of movement.
In operation, at least one first workpiece to be welded is placed on the first workpiece support, while at least one second workpiece to be welded is fixed to the second workpiece support, dedicated tooling providing the connection between each workpiece support and the corresponding workpiece to be welded. The machine is set up so that during a heating step the first face of the heating plate can be pressed onto the first workpiece to be welded on the first workpiece support, while the second workpiece to be welded is pressed against the opposite face of the heating plate by the second workpiece support. The second workpiece support is then moved away, after which the heating plate is moved away from the first workpiece to be welded carried by the first workpiece support and then withdrawn from the two workpiece supports. The second workpiece support is operated again to press the connecting surfaces of the two workpieces to be welded against each other, the plastics material being sufficiently softened or melted to assure a weld.
Clearly, for each given machine, the various movements that are necessary limit the maximal dimensions of workpieces that can be welded.
Workpieces of different shapes can be welded on the same machine by fitting appropriate dedicated tooling, but setting up the machine is complex because the travels of the cylinders moving the heating plate and the second workpiece support device are affected by the differences in the dimensions of the tooling and the workpieces to be welded.
Accordingly, in document FR 2 320 839 A, the adjustment can be effected by the cylinders moving the first workpiece support. This kind of adjustment is not reliable, however, and no adjustment means are explicitly described, and also this document concerns the welding of storage battery housings, the dimensions of which would appear to be constant.
Document FR 2 688 736 A describes a similar machine, but in which the first workpiece support is fixed, without any adjustment means.
Document GB 2 085 354 A (
FIG. 5
) describes a similar machine in which the heating plate is suspended vertically from a carriage that is movable to adjust it, and so is not positively held so that it can be moved along a particular welding travel. This means that the weld is not reproducible.
Accordingly, in prior art machines, there are no means for reliably and quickly adjusting the machine to track variations in the size of the workpieces to be welded, and to maintain the pressures exerted during operation of the machine effectively.
SUMMARY OF THE INVENTION
The problem addressed by the present invention is that of designing improvements to machines for welding workpieces using heating plates which, without modifying the overall size of the machine, and using conventional tooling available until now, significantly increase the possible variation in the dimensions of the workpieces that the machine can weld, retaining good reproducibility of the weld.
The improved possibilities of modifying the dimensions of workpieces to be welded must preferably be obtained without complicating the operations of control of the cylinders actuating the mobile parts of the machine, and without increasing the travel itself of the cylinders, so preserving a good speed of the welding cycle.
Accordingly, an improved machine in accordance with the invention must be able to replace a plurality of existing machines each suited to a range of dimensions of the workpieces to be welded.
To achieve the above and other objects, a welding machine in accordance with the invention having a heating plate comprises a frame, a heating plate, a first workpiece support device, a second workpiece support device facing the first workpiece support device, first means for moving the heating plate along an insertion travel parallel to its plane between a welding position engaged between the first and second workpiece support devices and a loading position withdrawn from the first and second workpiece support devices, second means for moving the heating plate along a welding travel perpendicular to its plane between two extreme positions, and third means for moving the second workpiece support device along a contact travel perpendicular to the plane of the heating plate toward and away from the first workpiece support device and between respective bearing and withdrawn positions, together with means for moving the first workpiece support device perpendicular to the heating plate toward or away from the second workpiece support device.
The first workpiece support device further comprises:
an adjustable position table, mounted on the frame, being movable it toward or away from the second workpiece support device, and
means for locking the table in a particular position chosen from a set of predefined positions and to withstand thus pressure forces exerted on the table during operation of the machine.
This means that the workpiece supports and the heating plate are mechanically strong, to guarantee good reproducibility of the weld.
For example, the means for locking the table comprise transverse screws selectively engaged in corresponding holes in respective fixed lateral guide plates of the frame and in guide brackets carried by the table.
Improved possibilities of adjusting the machine can be obtained by further providing indexing means for indexing the welding travel of the heating plate by moving its two extreme positions of welding travel perpendicularly to the plane of the heating plate toward or away from the first workpiece support device.
In one advantageous embodiment, the table comprises a top plate joined to a bottom support by expandable connecting members each including a first arm, one end of which is articulated to the bottom support and the other end of which slides under the top plate, and a second arm, one end of which is articulated under the top plate and the other end of which slides on the bottom support, the two arms being articulated to each other in their central areas, the sliding end of the second arm being slid horizontally on the bottom support by a cylinder to adjust the height of the table.
The design of a machine of the above kind can be adapted to heating plates oriented vertically or horizontally. In a preferred embodiment, the heating plate is oriented in a substantially horizontal position, its
Eilberg William H.
Etudes Realisations Techniques et Commerciales
Mayes Curtis
LandOfFree
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