Metal working – Means to assemble or disassemble – Puller or pusher means – contained force multiplying operator
Reexamination Certificate
2001-03-12
2003-04-15
Watson, Robert C. (Department: 3723)
Metal working
Means to assemble or disassemble
Puller or pusher means, contained force multiplying operator
Reexamination Certificate
active
06546610
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a device for removing a screw or pin tightly seated in a mounting hole of a bearing eye or the like, especially a tightening screw or fastening screw of a pivot pin or the axle component of a motor vehicle axle, with a support body having a lateral support wall, with which support wall the support body can be attached to the bearing eye in the area of the screw, wherein the support body is provided with a pressing device acting on the screw.
BACKGROUND OF THE INVENTION
Motor vehicle axles in which essentially cylindrical pivot pins are held clampingly in a bearing bore of a slotted bearing eye have been known. The pivot pin is part of a ball-and-socket joint, which is arranged, e.g., at the outer end of a suspension arm of a motor vehicle axle. The bearing eye with its bearing bore for receiving the pivot pin may be arranged, e.g., at the upper end of a steering knuckle of the motor vehicle axle. To hold the pivot pin tightly in the bearing bore, the bearing eye has a clamping slot, which extends radially in relation to the bearing eye in the area of the bearing bore and by which two clamping flanges are formed, which are provided with a corresponding mounting hole for a tightening screw. In cooperation with a tensioning nut which can be screwed onto the tightening screw, the bearing bore can be tensioned by the tightening screw. The pivot pin is tensioned in a tightly seated manner in the bearing bore by this clamping operation. To also ensure that the pivot pin cannot slip out of the bearing bore even when the tightening screw is loosened but not removed, this tightening screw is arranged, extending at right angles to the bearing bore, at a radially spaced location from the bearing bore, at which the tightening screw laterally protrudes at least partially into the bearing bore. The pivot pin correspondingly has a circular mounting groove, into which the tightening screw protrudes in the mounted state. Thus, there is a positive-locking connection between the tightening screw and the pivot pin via the circular mounting groove of the pivot pin, so that the pivot pin cannot slip out of the bearing bore of the slotted bearing eye even when the tightening screw is loose.
It has been found with this type of joint connections that the tightening screw rusts into its mounting holes after a prolonged operating time and thus can be removed only with difficulty. It is sometimes necessary to heat the bearing eye in order to be able to move the tightening screw in the mounting holes at all. However, the ball-and-socket joints, which are provided with rubber cuffs toward the bearing eye, are very greatly affected by this heating of the bearing eye. The consequence of this is in turn that during simple repair work, during which the ball-and-socket joints are actually not to be replaced, these ball-and-socket joints are damaged and must be additionally replaced, as a result of which the repair costs increase considerably. However, since the tightening screw partially protrudes into the bearing bores of the pivot pins, complete removal of the tightening screw is absolutely necessary for the removal of the pivot pins from their bearing bores.
For example, a device which is intended especially for pressing out pivot pins of a steering linkage of motor vehicles has been known from DE-GM 69 01 578. However, this device is suitable only for pressing out conical pivot pins which become completely loosened after a short pressing-out movement simply because of their conical design in the bearing bore of the pivot pin, which likewise has a correspondingly conical design. For support in the area of the bearing eye, this device has a support body with a support wall arranged at right angles to the longitudinal extension of the device in the form of a support fork. A threaded cylinder with internal threads, which is arranged approximately concentrically to and opposite the support fork, is provided at the other end of the support body opposite the support fork. A pressing spindle acting as a pressing device, by means of which the pivot pin can be loosened in the bearing eye with the prior-art device attached to the bearing eye, is screwed into the threaded cylinder. It was now found that this device is not suitable for pressing out an extremely tightly seated tightening screw of the above-described type because especially the part of the pressing spindle that points toward the bearing eye and presses the threaded section of the tightening screw always becomes deformed. Furthermore, great wear can also be observed on the thread of the pressing spindle if this prior-art device is frequently used to press out extremely tightly seated :pivot pins. However, the internal threads of the threaded cylinder will also be damaged by this wear over time, so that this device cannot be used any longer already after a short time.
Furthermore, motor vehicle axles in which shock absorbers are fastened to the axle body via a bearing eye have been known. The bearing eye has a mounting hole for this, through which a fastening screw is passed. The bearing eye of the shock absorber is mounted between two bearing flanges, through which the fastening screw passes as well. To securely hold the bearing eye between the bearing flanges, the fastening screw is provided with a retaining nut. It was also observed in this case of connection that the fastening screw can rust into the mounting hole of the bearing eye after a prolonged operating time of the vehicle and its removal, e.g., to replace the shock absorber, is extremely difficult. The fastening screw is frequently seated in the mounting hole so tightly that it cannot be loosened and pushed out with conventional means any longer. The above-mentioned prior-art device is also unsuitable for loosening such fastening screws, because the pressing spindle is also damaged in the case of extremely strong pressing forces.
SUMMARY AND OBJECTS OF THE INVENTION
The basic object of the present invention is therefore to provide a device by means of which extremely strong pressing forces can be applied to loosen and/or press out a screw or pin tightly seated in a mounting hole without the device being subject to increased wear.
The object is accomplished according to the present invention by the pressing device having a guide cylinder, in which a stud is guided axially displaceably in a guide hole for loosening and/or pressing out the screw and by a screw-down nut, which is screwed on the guide cylinder and is provided with a pressing surface acting on the stud, being provided for the axial displacement of the stud.
Due to the design of the device according to the present invention, extremely tightly seated screws or a pin can be reliably pressed out of a corresponding mounting hole of a bearing seat without the device itself being able to be damaged.
The pressing device has for this purpose a guide cylinder in which a stud is guided axially displaceably. To guide the stud, a guide hole is provided, which can be pushed fittingly over the threaded section of the tightening screw or fastening screw projecting from the bearing eye with the stud withdrawn. To apply the necessary strong pressing-out force, a screw-down nut with a pressing surface is provided, which is screwed onto an external threaded section of the guide cylinder, which threaded section has a relatively large diameter. Due to this relatively large diameter of the threaded connection between the screw-down nut and the guide cylinder, extremely strong axial forces can be applied by the screw-down nut via its pressing surface on the stud without the threaded connection being able to be damaged. Deformations of or damage to the stud are also ruled out because the stud is securely guided in the guide hole of the guide cylinder and is protected from external effects. Furthermore, the threaded connection between the screw-down nut and the guide cylinder is designed such that the use of an impact screwdriver is possible without damage to this threaded connection. Due to this design
Klann Tools Ltd.
McGlew and Tuttle , P.C.
Watson Robert C.
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