Metal deforming – By use of non-deforming work-gripping clamp and relatively... – Plural or complex apparatus
Reexamination Certificate
2002-09-17
2004-02-24
Crane, Daniel C. (Department: 3725)
Metal deforming
By use of non-deforming work-gripping clamp and relatively...
Plural or complex apparatus
C072S149000
Reexamination Certificate
active
06694794
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a draw-bending machine.
It is known that bent metal pipes are used in many application fields. For example, in the motor-vehicle industry pipes provided with a plurality of bends are used for making hydraulic and pneumatic circuits in cars and motorcycles. In particular for the braking and/or conditioning system or also for the cooling system of a motor.
In many cases accomplishment of several bends close to each other is required, which bends are disposed in different planes on pipes formed of two metal portions, usually made of aluminium, connected to each other by a flexible stretch, made of rubber for example.
In the known art, accomplishment of these bends is possible before assembling of the three portions forming the finished pipe.
Consequently, the resulting production cycle necessarily requires accumulation of the already bent metal portions waiting for being assembled, which may involve possible damage of said portions during transportation, storage or picking up of same from the magazine. In addition, due to the necessary accumulation of the semi-finished parts, availability of important spaces to store them is required.
Furthermore, since pipes must be submitted to tightness tests after being assembled, since they are not assembled before bending, use of complicated and expensive testing apparatus are involved which must suit the different shapes of the already bent pipes.
Draw-bending machines are known that enable accomplishment of bends in distinct planes on pipes formed of a single rigid portion.
They comprise pipe-locking and rotation means which is capable of causing forward movement of the pipe to be bent along a direction coincident with the longitudinal axis of the pipe and rotating the same around its own axis, and a bending head movable along two mutually perpendicular directions lying in a plane perpendicular to said advancing direction. The head comprises a bending die adapted to engage and disengage the pipe through combination of movements along the two perpendicular directions.
After carrying out a first bend, the head is moved away from the pipe, the pipe is caused to move forward and rotate to change the bending plane and the die is approached again for execution of a second bend.
Such a type of machine is known from document EP0538207 in the name of the same Applicant.
It comprises a base structure on which the supporting, rotation and locking members of a pipe to be bent are mounted in cantilevered fashion. Linked to the base structure is a bending head comprising a first slide movable on first horizontal sliding guides integral with the base structure and a second slide slidably in engagement with the first slide by means of vertical sliding guides integral with said first slide. Two bending dies disposed spaced apart from each other at a superposed position can be positioned on the second slide.
It is also known from document U.S. Pat. No. 4,945,747 an apparatus for bending elongated materials in any direction which includes a chucking unit, an arm robot having at least three swiveling arm segments, a bending head provided on a free end of the arm segment and a moving device for moving the robot along a line parallel to the chucked material.
The machines of the known art briefly illustrated above do not allow pipes consisting of a flexible central portion to be dealt with.
In fact, for changing the bending plane they cause rotation of the pipe about its own axis; this operation is much more complicated, if not impossible, where the pipe is provided with a median rubber portion, because the latter tends to flex and twist.
SUMMARY OF THE INVENTION
Under this situation the technical task underlying the present invention is to conceive a draw-bending machine capable of obviating the mentioned drawbacks.
In particular, it is an aim of the present invention to conceive a draw-bending machine enabling bends to be easily executed in different planes on two rigid metal portions of a pipe provided with a median flexible stretch.
It is a further aim of the present invention to provide a draw-bending machine adapted to easily handle the pipes from loading of same onto the machine until unloading therefrom without external interventions being required.
The technical task mentioned and the aims specified are achieved by a draw-bending machine comprising: a base frame; a bending head movably in engagement with the base frame and including at least one bending die rotatable about a bending axis; a support and positioning device of said at least one bending head, said support and positioning device being linked to the base frame; handling and locking means for a pipe to be bent; the support and positioning device of said at least one bending head presenting: a first support arm movably in engagement with the base frame, said first support arm having a first end and a second end opposite to the first one; first actuating means of the first support arm; second actuating means of the first support arm; a second support arm having a first end hinged on the first end of the first support arm at a first articulation axis and a second end hinged on the bending head at a second articulation axis; third actuating means of the second support arm around the first articulation axis; fourth actuating means of the bending head around the second articulation axis; the draw-bending machine being characterized in that the handling and locking means for the pipe to be bent comprises a first gripping unit having a first and a second clamps aligned along a first alignment direction to tighten the pipe to be bent at two regions spaced apart from each other.
REFERENCES:
patent: 3299681 (1967-01-01), Hautau
patent: 4945747 (1990-08-01), Yogo
patent: 5099669 (1992-03-01), Del Fabro
patent: 5291771 (1994-03-01), Tomo et al.
patent: 5927126 (1999-07-01), Biella
patent: 3620151 (1987-02-01), None
patent: 3620151 (1987-02-01), None
patent: 0 538 207 (1992-10-01), None
patent: 1 065 015 (2000-06-01), None
patent: 2 187 666 (1987-03-01), None
patent: 2-299724 (1990-12-01), None
Crane Daniel C.
Fabbrica Macchine Curvatubi Crippa Agostino S.p.A.
Pearne & Gordon LLP
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