Metal working – Means to assemble or disassemble – Spreading parts apart or separating them from face to face...
Reexamination Certificate
1999-09-16
2001-04-03
Scherbel, David A. (Department: 3723)
Metal working
Means to assemble or disassemble
Spreading parts apart or separating them from face to face...
C029S271000, C029S272000, C269S043000
Reexamination Certificate
active
06209182
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The invention concerns a set for separating cylindrical pipes pushed into one another in an axial direction, in particular discharge pipes, said set having at least one gripper, which has two grabbing arms that extend azimuthally and a clamping device, and said gripper is connected to a lever with a component extending in a radial direction.
2. Description of the Prior Art
In installation practice, pipes are often fitted into one another in a longitudinal direction and sealed off against one another by means of rubber gaskets. To facilitate easy assembly and adjustment without high energy expenditure, pipes and seal are greased in advance with a lubricant or slip agent, which, as long as it is moist, allows the pipes to be pulled apart with relatively little energy if assembly is defective or to subsequently change the pipe location. However, if the lubricant is dry the two pieces of pipe can only be separated using considerable energy so that damage cannot be ruled out. Here the dry rubber gasket acts to brake sliding, which makes is it significantly more difficult to pull the pipes apart. A second person is required to hold the pipe steady. But even if the lubricant is still moist the pipes may stick together, favoured by the penetration of dirt, sand stone dust and similar, so that it is no longer possible to separate the pipes with conventional aids without destroying them.
If the transferable power generated by bear hands is insufficient, the use of a gripper is conceivable, which grips the pipe via two grabbing arms and is connected to a lever, which enables the transmission of high torque to the pipe so that the fit of the pipes can be loosened through a relative twisting of one pipe in relation, to another Particularly suitable for this purpose are pipe wrenches. However, the axial transmission of force required to loosen the pipes is hardly possible or impossible by means of a pipe wrench and, owing to the high forces acting upon the pipes via the lever, the probability of damage is high.
SUMMARY OF THE INVENTION
By way of contrast the invention has the object of providing a set of the kind described at the beginning, which allows relatively easy separation of the assembled pipes, which are possibly stuck together, with little application of force and consumption of time, and as far as possible in a non-destructive manner.
The task is solved by the inventive device in that on the gripper, pointing in an axial direction, a web that extends azimuthally is integrally moulded, said web rising in the manner of a flank in the azimuthal region. A second gripper with at least two grabbing arms and a clamping device is provided and said gripper is connected to a lever with a component extending in a radial direction. On the second gripper a nose that extends radially is integrally moulded, said nose being disposed in the axial region of a rising flank of the web and projecting beyond said web.
The basic idea of the invention is as follows: initially, with the aid of a second gripper with lever, the pipe that is not to be removed is fixed. It can therefore no longer twist so that on the one hand the probability of damage is decreased and on the other the transmission of force to the pipe to be removed is more effective. Furthermore, the nose, interworking with the web, causes the two grippers, and thus also the pipes, to be pressed apart, when twisted relatively to each other, in an axial direction and thus separated. This functions as follows: initially, one of the grippers is affixed to the pipe to be removed and the other gripper to the pipe connected thereto by attaching the grabbing arms via the respective clamping device. Within the meaning of the invention, a clamping device is understood to be a device that connects the grabbing arms to each another and to the lever and enables the grabbing arms to be pressed against the pipe. Now, the grippers are twisted in a mutually opposing direction of rotation about the joint longitudinal ax of the pipes through tile application of force upon the levers, until the nose bears against a rising flank of a web disposed on the other gripper. When the grippers are twisted further relatively to each other, the nose slides along the flank of the web so that due to the axial rising the two grippers and thus also the pipes connected to each other are pressed apart from each other in an axial direction. In this way, with the relatively small application of force a large axial force component can be transmitted to the two pipes, without, as is the case, for example, with the use of a single gripper, the occurrence of high transverse forces, which not only increase the force expenditure but can also cause the destruction of the pipes. The pipes are pulled apart by the inventive set under a relatively low expenditure of force and can be separated without destruction. Thereby both grippers can also possibly be operated by one person, a second person is no longer required to hold the pipe steady.
In an advantageous embodiment, the clamping device of at least one of the two grippers has a locking arrangement that guarantees that both grippers must no longer be simultaneously both tensioned and turned. The loosening of a pipe connection is made considerably more easy and can be effected by only one person.
One gripper of the inventive set can also be used on pipes extending in wall recesses if the side on which both grabbing arms open lies opposite radially to the respective lever. Thus both arms can be inserted via the lever from outside into the wall slot and pushed on to the pipe. After closing the clamping device, the grabbing arms bear against the pipe, and the gripper can be turned by applying force upon the lever.
Affixing the grabbing arms to the pipe, in the same way as pincers, can be achieved via two limbs. The limbs are connected to each other via an axis so as to be articulated and by swiveling in relation to each other press the grabbing arms against the pipe. The lever, which serves to transmit the turning effort, is attached to the limb.
Alternatively or supplementary thereto, a tightening bolt is conceivable, which when tightened presses the grabbing arms against the pipe. Owing to the frictional forces, the clamping device is locked without additional measures.
To ensure that the grabbing arms are pressed as firmly as possible and, to avoid high point-to-point forces acting upon the pipe, as evenly as possible, the clamping device applies a clamping force to the grabbing arms at their two ends in relation to each other. It is conceivable, for example, that the grabbing arms at their ends are connected to each other via respectively one tightening boll. By tightening these bolts, the grabbing arms are affixed to the pipe. Owing to the fact that the two bolts can be adjusted independently of each other, the clamping forces can be distributed equally across the circumference of the pipe.
The grippers of the inventive set can be used especially effectively if their grabbing arms are adapted to the respective diameter of the pipes to be separated. However, in order that a separate set is not required for every common pipe thickness, the grabbing arms are preferably connected to the clamping device so as to be releasable and therefore can be exchanged as required. By way of contrast other components of the gripper can be used independently of the respective pipe size.
A decisive objective of the inventive set is the effective transmission of torque to pipes without causing damage, which can occur, for example, when the contact pressure is too high. For this reason, in a preferred embodiment, the grabbing arms of at least one of the grippers are provided with a coating on the radial inner sides, which bear flat against the pipe and thus enable a maximum transmission of torque.
The grip can be further improved via a suitable structuring of the radial inner sides of the grabbing arms. Suitable for this purpose are especially knob or groove structures.
Pipes that are to be se
Scherbel David A.
Schindler Edwin D.
Wilson Lee
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