Patent Application
20060055125
This application claims the priority of German Application No. 10 2004 044 287.8, filed Sep. 10, 2004, which is incorporated herein by reference.
The invention relates to a clamping device for fixing a wheel rim of a vehicle wheel to a shaft of a balancing machine. More particularly, the invention relates to a quick-clamping device for securing a vehicle wheel to a shaft of a balancing machine. Even more particularly, the invention relates to a quick-clamping device for adjustably, fixedly securing a vehicle wheel rim to a centering shaft of a wheel balancing machine with little effort.
DE 38 08 755 C2 describes a quick-clamping device in which the conical assembly is pressed into the centering hole of the vehicle wheel rim by a spring exerting force axially. The spring travel is determined so that for rim centering holes of different diameters the conical assembly engages the centering hole of a rim with its outer centering surface. As a result of this, the spring must always be compressed more or less axially during tightening of the rim against the flange. This spring force must therefore be overcome with the clamping element. This is laborious and particularly demanding, if the clamping element is a clamping nut, which is screwed by hand onto the outer threads of the shaft. In this case, not only the spring force, but moreover the friction force resulting from the contact between the spring and the threads, must also be overcome.
DE-OS 23 61 847 describes a device for centering ring-shaped objects around a spindle, which features a truncated cylinder-shaped part, which in turn features both a central bore for mounting the truncated cylinder-shaped part onto the spindle as well as radial slots. The truncated cylinder-shaped part features on its axially tapered end a cylindrical protrusion, on which a cup-shaped part is mounted so that it can be clamped displaceably on the axis of the truncated cylinder-shaped part. To secure a centering object, the truncated cone-shaped part must first be pulled outward after the clamping nut is released and, after the object to be centered is introduced, must then be pushed forward again with its central hole on the truncated cone-shaped part, so that the cup-shaped part is clamped against the truncated cone-shaped part and so the central hole of the object to be centered is centered on the outer surface of the truncated cone-shaped part, wherein at the same time the slotted truncated-cone shaped part, owing to its slots, is clamped with its inner bore against the spindle. Through a clamping procedure the object to be centered is secured to the truncated cone-shaped part, which is in turn secured to the spindle at the same time. This device of the prior art is tedious to use, since the truncated-cone-shaped and cup-shaped parts must first be separated and then, after the object to be centered has been mounted, must then be brought back together, before clamping can be performed. A further disadvantage can be found in the fact that when clamping a vehicle wheel the contact edge of the cup-shaped part makes contact with the side of the vehicle rim facing away from the truncated-cone-shaped part, with which the rim does not make contact on the securing flange of the axle when it is mounted on the vehicle. A dynamic balancing of the vehicle wheel is therefore not possible. The decisive disadvantage, however, can be found in the fact that following clamping the axial position of the device is not set, therefore making this prior art device unsuitable for clamping a vehicle wheel onto the shaft of a balancing machine.
DE 195 11 405 A1 describes a clamping device for use in clamping vehicle wheels to a shaft of a balancing machine, wherein the conical assembly is pressed into the center hole by a spring exerting force axially. This prior art device therefore has the same disadvantages as those of the device proposed in DE 38 06 755 C2 mentioned above.
As in the previous devices, the device proposed in DE 42 00 380 A1, features a centering cone pressed into the centering hole by spring force. The same is true of the device proposed in DE 28 13 387 A1.
DE 36 05 821 A1 describes a quick-action clamping nut for use in clamping the rim of a vehicle wheel to shaft of balancing machine, wherein an end of the shaft features outer threads. The quick clamping property is thereby realized through the fact that the threads are located in two radially movable jaws, so that the threads can be engaged and disengaged through the movement of the jaws. This quick-clamping nut of the prior art does not feature a centering cone.
An object of the present invention is to create a quick clamping device for securing vehicle wheels to a wheel balancing machine, and in which the disadvantages of the prior art quick clamping devices are avoided and, in particular, the securing of the rim to the flange is simplified.
This object of the invention has been solved through the teachings in accordance with the invention set forth below.
A fundamental teaching in accordance with the invention includes that the engagement of the conical assembly with the centering hole of a vehicle rim no longer needs to be effected by use of a spring, but can instead be realized by use of the forces resulting from the tightening of the rim against the flange. To this end, the inventive clamping device to be used for securing the rim against the flange abuts a tubular component, which is connected to the conical assembly and is disposed on the shaft of the wheel balancing machine in such a way that it is axially displaceable thereon. When the clamping device or element is secured, the forces of the clamping device or element are then transmitted to the conical assembly and are centered by this component on the inner wall of the centering hole of the vehicle rim. Overall, only the required force for securing the rim against the flange must be overcome by the clamping device or element. The tightening travel is therefore as small as possible, as is the work required for such securing.
The invention likewise includes that an outer wall of a tubular component according to the invention includes outer threads, onto which the clamping nut, in particular a quick-clamping nut, can be screwed. With the exception of minor friction forces in the threads, essentially no other forces are required when the clamping nut is being screwed into position. Centering can be accomplished with practically no output of force, with force being necessary only for securing the rim against the flange.
Because the conical assembly is displaceable in relation to the inventive tubular component extending from its tip, the conical assembly can be placed in various axial positions, before the centering hole of a rim is introduced and the conical assembly is driven into the centering hole. If wheels with centering holes of the same diameter are clamped, the conical assembly has the same axial position in the centering position. For this reason, it is advantageous according to a further embodiment of the invention to feature an adjustment device or element with which the axial position of the conical assembly can be adjusted, that is, preset in relation to the constant diameter of the centering holes.
According to a further development of this embodiment of the invention, the inventive adjustment element includes a threaded spindle, which extends within the tubular part and abuts the shaft of the balancing machine, or a part connected thereto, with one end and engages the threads of a supporting piece, which is securely connected to the tubular component, wherein a turning knob is provided on a part extending axially from the supporting piece of the threaded spindle, wherein the knob can be employed also through different means to facilitate the turning of the threaded spindle.
It is advantageous if the inventive adjusting device or element can also be realized as an arresting device or element or locking element, through the assistance of which the conical assembly can be adjusted to various displacement settings. The arresting element can be realized in many different ways. It is advantageous if the arresting element includes an axially spring-loaded ball or similar component at the shaft or a component connected thereto, whereby the ball or similar component is present opposite the arrest recess in the tubular component. In a similar realization of the adjusting device or element, it is also possible after introducing a vehicle wheel to manually bring the tubular component so far forward axially, that the conical assembly is centered in and engages the centering hole of the rim of the vehicle. This setting results in the ball being arrested in an opposite lying recess, so that this position of the conical assembly remains locked for subsequent clamping involving rims with centering holes of equal diameter. The conical assembly can be manually adjusted to another arresting position, and thereby centering position, by hand when being used on wheels with centering holes of various diameters.
It is advantageous if it can be ensured that rotation of the conical assembly in relation to the shaft or an extension thereof is restricted in accordance with the invention.
The conical assembly can be realized very simply as a cone, which is moved into the centering hole of a vehicle rim during centering and thereby facilitating actual centering with its conical outer surface. It is especially advantageous, however, if in a further embodiment of the invention the conical assembly includes an outer central portion with a cylindrical outer surface for engaging the centering hole of the vehicle rim and includes a conical inner surface which the cone of the conical assembly engages with its conical outer surface, whereby the centering part comprises radially movable segments separated from one another. Centering can also be facilitated through the movement between the conical surfaces of the cone and the segments of the outer centering portion, which has the advantage that these surfaces can be slid over each other with a high degree of precision. The position of the cylindrical outer surface of the centering part in relation to the conical surface is also very exact, and, owing to the cylindrical form facilitates a securely centered positioning in the inner edge of the centering hole of a rim.
In a further development of this embodiment of the invention, the segments also feature radially extending guides, which are radially displaceable in the guides extending radially in the flange. The form of guides can be realized according to preference. For example, they can be rods, which are introduced into radial bore. In an advantageous further development of this embodiment according to the invention, the guide parts feature the form of radial flanges, which are inserted into radially running slots, and which are preferably found on the flange for receiving the vehicle rim. In an advantageous configuration, the segments are drawn radially inward by a spring device or element, so that a clearance-free positioning on the cone is ensured. It is advantageous if the spring element or biasing element is a ring, preferably a rubber ring, which runs in a peripheral groove of the segment.
Embodiments of the invention are explained in further detail below with reference being made to the drawings.
Relative terms such as right, left, up and down are for convenience only and are not intended to be limiting.
A cone 20 is mounted axially displaceable on the tubular part 10 with narrow clearance. Extending from its point is a tubular element 22, which is formed from the same piece as the cone 20 and, like the cone, is axially displaceable on the tubular part. Extending over a defined length in the tubular part 10 is a groove 24, in which the rod 26 provided in the tubular element 22 is displaceably engaged, thereby preventing rotating of the tubular element 22 in relation to the tubular part 10. On the outer wall of the tube 22 are outer threads 28 onto which a clamping screw can be screwed, as shall be explained below with reference drawn to
On a conical outer surface 30 of the cone 20 segments 32 with complementing conical inner surfaces are provided and form an outer centering part with a cylindrical outer surface 36 for centering and engaging a centering hole of a vehicle rim. A rubber ring 38 holds the segments 32 with their conical inner surfaces 34 in position with the conical outer surface 30 of the cone 20. Each segment 32 includes a radially extending flange section 40, which is radially displaceable in the radial slots 42 of a flange 44. The flange 44 includes a contact surface for the rim of a clamped vehicle wheel and is connected via a cup 48 to the extending part 6 and thereby with the shaft 2.
To clamp the rim 50, the inner surface 54 of the rim 50 of the vehicle wheel is first placed on the cylindrical outer surface 36 of the segment, wherein the cylindrical outer surface 36 still has a smaller diameter than that of the inner surface 54 of the centering hole of the rim owing to the strength of the rubber ring 38. The clamping nut 56 is then screwed on, wherein virtually no screwing force is required, until the intermediary ring of the clamping nut 56 makes contact with the rim 50, the surface of which is tightened against the contact surface 46 of the flange 44. When using a quick-clamping nut, it is not necessary to first engage the inner threads with the outer threads 28 immediately after mounting the nut on the tubular element 22. Instead, the tubular element 22 can first be shifted manually to the right in the drawing to partly complete the centering. The quick clamping nut is brought via its intermediary ring 60 into contact with the rim 50, before its inner threads are then engaged with the outer threads 28 and tightened.
While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 044 287.8 | Sep 2004 | DE | national |
