Bearings – Linear bearing – Recirculating
Reexamination Certificate
1999-12-21
2002-09-03
Marmor, Charles A (Department: 3681)
Bearings
Linear bearing
Recirculating
C384S015000
Reexamination Certificate
active
06443619
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a guide unit comprising at least one guide rail, optionally a rectilinear guide rail, this guide rail having a longitudinal axis and a rail profile with at least one track, also comprising at least two guide carriages guided on the at least one track of the guide rail with mutually facing ends and a covering means for covering the guide rail at least in a longitudinal portion of the guide rail between the two mutually facing end parts of the at least two guide carriages.
The covering part covering the guide rail protects the guide rail from contamination in guide units of this type.
STATEMENT OF THE PRIOR ART
It is known to use bellows as covering means; sheet metal angles are also conceivable.
OBJECT OF THE INVENTION
It is the object of the invention to provide a covering means which is improved with respect to ITS production and its handling when being fitted into the guide unit.
SUMMARY OF THE INVENTION
To achieve the above object, it is proposed according to the invention that the covering means makes a driving connection with the at least two guide carriages for common movement therewith and has a substantially rigid configuration in the axial direction between the two mutually facing ends at least over a portion of its longitudinal dimension.
In particular, it is intended that the covering means, at least over a portion of its longitudinal dimension, forms a covering means profile which approximately follows the rail profile at a distance from it—when viewed in a section orthogonal to the longitudinal axis. The covering means can define a substantially closed profile cavity between the rail profile and the covering profile, which contains the at least one track of the guide rail extending between the two guide carriages.
The profile cavity can be sealed in that the profile cavity is sealed, optionally substantially tightly by formation of a narrow gap and/or contact zone between the guide rail and the covering means. This seal of the profile cavity can, on the one hand, be used to prevent soiling of the guide rail from the surrounding space and, on the other hand, also help to prevent the discharge of lubricant and to prevent the lubricant used to lubricate the guide carriage and, in particular, the points of engagement of the guide carriage with tracks from issuing into the surrounding space. Both requirements arise in many applications of the guide unit, particularly if the guide unit is used in robot construction, in machine tool construction, in assembly machine construction and the like.
A frequent design of guide carriage is based on the principle that the guide carriage surrounds a guide rail, which is approximately rectangular in cross-section, in the form of a U, so the transverse web of the U-shaped guide carriage opposes a top face of the guide rail whereas the two outer arms of the U each oppose one lateral face of the guide rail, and a base of the guide rail opposing the top face is designed to be fastened on a carrier. Guidance can be effected by endless races of antifriction members arranged with a respective load-transmitting row of antifriction members in a track of the guide carriage and in a track of the guide rail. Balls, needles and rollers and the like can be used as antifriction members. With a design of this type, the covering means profile will preferably be constructed as a U-profile, wherein the ends of the arms of the U of the covering means profile can rest in a sealing manner on the guide rail.
The covering means profile can be assembled from at least two partial profiles following one another in a circumferential direction round the longitudinal axis. “Assembled” means that the partial profiles can be produced separately and rest with their rims or edges against one another. However, “assembled” also means that the U-profile parts adjoin one another in one piece or are connected to one another in the manner of a hinge.
If partial profiles of the covering means profile following one another in the circumferential direction are articulated to one another round hinge axes parallel to the longitudinal axis, then it is possible to mount and dispatch the covering means profile in an approximately laid-flat state, so storage space and transport space are saved. A further advantage is that laid-flat covering means profiles can be fitted on site even under restricted spatial conditions, for example if a table is already mounted on two or more guide carriages following one another. In this case, a laid-flat covering means profile can be introduced in laid-flat form through a gap between guide rail and table and can then be caused to cover the guide rail by pivoting the partial profiles round the hinge pins.
It is conceivable that the covering means profile is assembled from at least two covering profile portions adjoining one another in the longitudinal direction.
Exact fixing of the length of the covering means profile is unnecessary if the covering means profile has length compensating means for adaptation to variations in spacing between the two guide carriages.
The covering means, in the vicinity of at least one guide carriage, can have a covering means joining element for producing the driving connection to the respective guide carriage. There are a number of alternative designs for this. It is basically conceivable to mount the covering means profile on the associated guide carriage on its lateral faces extending parallel to the longitudinal direction, for example by clipping. It should be noted with this solution, however, that the covering means profile, if it is resting against a transverse web of a U-shaped guide carriage, could impair the connection between the guide carriage and the table. A preferred embodiment therefore proposes that the covering means profile is accommodated within the contour of the guide carriage.
The covering means profile can be constructed at one or both ends with a covering means joining element for joining to the respectively associated guide carriage. The joining elements could both be mounted rigidly on the covering means profile. Therefore, the covering means can only be used for normal solutions, however, in which the spacing between successive guide carriages is predetermined. The spacing between successive guide carriages often varies. To allow for such varying spacing, there are also various solutions: for example, the covering means profile can be assembled from two covering profile portions which are each connected only at one end to a covering means joining element. Covering profile portions of this type with a covering means joining element arranged rigidly thereon, for example with the maximum necessary length, can be injection moulded from plastics material and one or both covering profile portions can then be shortened at the end remote from the respective covering means joining element so the sum of the lengths of the two covering profile portions corresponds to the spacing between succeeding guide carriages. A coupling part, optionally in conjunction with a seal, can then be arranged at the abutting ends of the two covering profile portions.
However, the covering means joining elements and the covering means profiles can also be produced separately. This separate production affords the advantage that the covering means profile can then be prepared as piece or bar goods and the length required in each case can be cut from it. This allows simple production, for example by intrusion or extrusion. The covering means joining element can be connected to the covering means profile by pushing them together. Simple length compensation can also be achieved in this way. To allow handling of this type, the covering means joining element will preferably be constructed with a driving part and a profile gripping part, the latter interacting with the covering means profile. The profile gripping part can be constructed for contacting the exterior of the covering means profile or for interacting with the interior of the covering means profile.
The profile gripp
Baker & Botts LLP
Marmor Charles A
Pang Roger
Rexroth Star GmbH
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