Metal deforming – By application of fluent medium – or energy field – Using fixed die
Reexamination Certificate
1998-09-17
2001-02-06
Jones, David (Department: 3725)
Metal deforming
By application of fluent medium, or energy field
Using fixed die
C072S455000, C100S214000
Reexamination Certificate
active
06182488
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a clamping device for holding together parts of a forming tool in internal high-pressure forming with a tool carrier forming a clamping jaw, a tension clamping holder which extends from the tool carrier so as to be offset relative to the working position of the forming tool, a movable clamping jaw which is arranged opposite from the tool carrier, and a quarter-turn or bayonet clamping device for holding together the forming tool parts between the movable clamping jaw and the tool carrier, which bayonet clamping device wedges the movable clamping jaw between the tension clamping holder and the forming tool.
2. Description of the Related Art
Clamping devices of the kind mentioned above are known for holding together parts of a forming tool in internal high-pressure forming, in which the tool carrier, together with the tension clamping holder, is constructed in a cup-like manner with the cup base as tool holder. Openings are provided in the vertical cylindrical cup wall for introducing pressure fluid supply lines to be applied to a workpiece to be formed and for charging the forming tool with a workpiece to be formed. To install a tool, the clamping jaw is raised in the disengaged state of the bayonet clamping device until the cup-shaped tool holder is accessible from above. The tool and, as the case may be, spacers are then introduced vertically from above into the tool holder.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a novel clamping device of the type mentioned above which is easier to handle especially with respect to tool installations.
In a clamping device according to the invention which meets this object, the tension clamping holder has at least one feed opening which is suitable for feeding the forming tool into the working position in a direction vertical to the clamping direction.
In comparison to feeding from above as practiced in the prior art, the arrangement, according to the invention, of the tension clamping device such that the tool parts can be fed to the tool carrier horizontally from the side appreciably facilitates tool assembly.
The tension clamping device could have, e.g., two plates extending from the tool carrier at a distance from one another, so that a tool could be arranged proceeding from two sides between the plates on the tool carrier.
The largest possible free installation space results in a preferred embodiment form of the invention in which the tension clamping holder has holder columns extending from a tool carrier which is plate-shaped in particular and a carrier platform which is arranged at the holder columns at a distance from the tool carrier with an opening for the movable clamping jaw and hooking parts of the bayonet clamping device which are arranged around the opening, wherein the largest possible feed openings are formed between the holder columns.
In the clamping position, the clamping jaw then projects downward from the carrier platform, wherein it is wedged via the bayonet clamping device between a tool arranged on the tool carrier and the carrier platform. In an advisable embodiment form of the invention, the distance of the carrier platform from the tool carrier can be varied in order to adjust different clamping starting positions, i.e., the carrier platform can be raised or lowered.
In an advantageous embodiment form, the device has a lifting device for raising and lowering the clamping jaw, wherein this lifting device can serve simultaneously for holding the clamping jaw for as long as the clamping jaw does not rest against a forming tool.
According to a preferred embodiment, this lifting device which can also be formed, e.g., by one or more hydraulic cylinders, is arranged by a piston rod connected with the clamping jaw on an additional carrier platform which is arranged over the carrier platform, wherein the additional carrier platform is advantageously supported against the carrier platform having the opening. This last step ensures that no corresponding change in the lifting range of the lifting device is required when adjusting the initial clamping position by means of a vertical adjustment of the carrier platform having the opening.
Further, the device according to the invention has arrangements for vertical guiding of the clamping jaw moved by the lifting device, wherein these guides are substantially formed by guide rods and guide bushings which project from the carrier platform with the opening and are arranged at a plate which is connected to the upper sides of the clamping jaw and projects over the clamping jaw.
In a further advantageous embodiment of the invention, the bayonet clamping device has a bayonet ring mounted on the clamping jaw, wherein the bayonet ring is mounted in particular on an annular shoulder formed at the clamping jaw. The clamping of the clamping jaw by means of a bayonet ring of this kind which is rotatable relative to the clamping jaw has the substantial advantage over bayonet hook parts arranged directly at the clamping jaw that the clamping jaw itself need not be rotated in order to wedge the clamping jaw, which would be disadvantageous in consideration of the pressing contact against the tool.
To ensure short clamping paths when high clamping force is to be transmitted, the bayonet clamping device preferably has a plurality of bayonet hooks forming a toothed rim around the bayonet ring and forming the opening in the carrier platform.
In accordance with a further advantageous embodiment, the bayonet ring has engagement or application bearings for hydraulic rotational actuation devices, wherein these application bearings project upward and are guided through openings formed in the above-mentioned plate, wherein the plate can be provided with counter-bearings for the hydraulic actuation devices.
In a particularly preferred embodiment of the invention, the clamping jaw has, as a counter-clamping device, a counter-pressure chamber which can be acted upon by fluid pressure, e.g., the working pressure of the device, and which opposes deformations of the mold cavity that could occur, e.g., in that the clamping jaw gives way under the influence of the pressing forces occurring during the forming process and the tool parts accordingly move away from one another. The counter-pressure chamber could also be formed in a short-stroke cylinder acting on a clamping jaw and/or on the tool.
A part of the clamping jaw which rests against the tool is preferably movable relative to the rest of the clamping jaw and has a portion which is constructed in the manner of a pressure piston and which can be acted upon by the fluid pressure in the counter-chamber. Given an appropriate application of pressure, a giving way of the clamping jaw is compensated in that the movable portion correspondingly moves forward relative to the clamping jaw and accordingly holds the tool parts in place. The counter-pressure chamber is advisably provided with a flexible sealing lining which is formed in particular from a plastic membrane, so that no special steps need to be taken to seal the pressure piston portion. Due to the possibility of compensation by means of the counter-pressure chamber, it is possible for the parts critical for the stability of the clamping device to be constructed in a less solid manner because a yielding of the clamping jaw can be tolerated to a determined degree.
A construction of the carrier platform which is particularly advisable in this respect provides that the platform has an annular part having the opening with the hooks, the platform with bushing parts connecting the holder columns, and plate braces connecting the bushing parts with the annular part and is accordingly constructed in a relatively lightweight manner.
In a further advantageous arrangement of the invention, the tool carrier has undercut grooves for the clamping fastening of tool parts. Grooves of this type which are provided at a narrow distance from one another in particular and in which hooking holder clamps are disp
Anton Bauer Werkzeug-und Maschinenbau GmbH & Co. KG
Jones David
Kueffner Friedrich
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