DIFFERENTIAL PULL-OUT GUIDE

Description

The present invention relates to a differential pull-out guide for pull-out furniture parts, which has a body rail, able to be mounted on a furniture body, a pull-out rail able to be mounted on a pull-out furniture part, and a middle rail between these two. Each rail has here a front end, a rear end, a main surface and one or more secondary surfaces arranged thereon, which are arranged in an angled manner to the respective main surface. Body rail and pull-out rail have respectively one or more tracks on which rollers run in the case of use. The rollers are preferably all arranged on the middle rail as upper and lower rollers. The rollers have upper and lower contact points to associated tracks, wherein a contact point is to be understood to mean the region of the roller which contacts a track. Accordingly, in the case of use, on rotating of a roller, all the regions of a roller circumference become contact points as soon as, and as long as, they contact the associated track.

The pull-out rail has, in addition to fastening possibilities for a furniture body, a secondary surface on which an upper and a lower track are arranged. The upper track is contacted by lower contact points of the upper rollers of the middle rail. The lower track is contacted by upper contact points of the lower rollers of the middle rail. In other words, the pull-out rail runs between upper and lower rollers of the middle rail and is guided by these.

The body rail has an upper secondary surface with an upper track and a lower secondary surface with a lower track. On the upper track, the upper rollers of the middle rail run with their upper contact points, on the lower track, the lower rollers of the middle rail run with their lower contact points.

The rollers serve to take the differential pull-out guide from a closed position into an open position along a pull-out path in a pull-out direction. The closed position is present when the differential pull-out guide is fully pushed together; the open position, when it is fully pulled apart.

In order to enable this, the rollers act between the rails and roll on the said tracks of the rails, so that the latter can alter their relative positions to one another. Usually, the rollers are all rotatably arranged on the middle rail. The middle rail also has a differential roller, the function of which is explained further below. In addition to the mentioned rollers, the middle rail can have lateral guide rollers, which bring about a lateral guidance of the pull-out rail and in which the rotation axis runs parallel to the main surface of the middle rail. A lateral guide roller is thus tilted by approximately 90° to a roller or, in other words, is oriented orthogonally thereto.

A stop element of the body rail limits the pull-out path, by a stop surface of the middle rail running against the stop element of the body rail. Such a limitation is also to be found for the pushing together of the rails to a closed position.

During pulling out the pull-out rail, the middle rail moves synchronously with the pull-out rail, wherein it respectively covers half the distance of the pull-out rail. For this, the middle rail has a load-transferring differential roller which rolls between tracks of the pull-out rail and the body rail. This differential roller can have a changeable axis position relative to the middle rail. The pull-out rail runs here between the differential roller and a roller arranged there-above. When the end position of the pull-out rail is such that its end is still situated between the differential roller and the roller associated with it, this denotes a normal pull-out (also designated full pull-out). When the end position of the pull-out rail lies beyond this position, this denotes an over pull-out. This is desired and provided whenever the drawer held between a set of two differential pull-outs is to be pulled out from the furniture body more than the nominal installation length and is thus to be accessible. The middle rail is usually configured shorter than the body rail and shorter than the pull-out rail. The rear end of the middle rail, in the pushed-in state of the differential pull-out guide, is offset forward with respect to the rear end of the body rail and with respect to the rear end of the pull-out rail.

Pull-out guides are known with self-retracting devices, in which the pull-out rail is retracted automatically over a final section of the insertion path. These self-retracting devices are often integrated into the pull-out guide, as disclosed especially in WO 2008/119091 A1.

Problems in such differential pull-out guides result when the furniture parts which are held between them—in particular drawers or push bases—starting from a position of over pull-out, also designated hereafter as open position, are acted upon by a user on one side with force. Hereby, it can occur that the rear end of the pull-out rail contacts the middle rail with the formation of a frictional engagement, and both rails are pushed in further, rigidly connected to one another. This leads to an offset and ultimately, in the worst case, to the drawer not being able to be closed. The differential rails of both sides could also be pushed in irregularly, which leads to distortions of the device and unnecessary loads of the rollers, and closure faults.

The present invention therefore sets itself the problem of indicating an improved differential pull-out guide, in which these disadvantages do not occur.

This problem is solved by the features of claim 1, in particular in that a lateral guide roller of the middle rail is arranged in the pull-out path on the middle rail in such a way that in the open position it is touching a rear end region of the pull-out rail at least in the position of use.

The lateral contact which is enabled hereby on the main surface of the pull-out rail leads to the latter, in the region of the very last section of the pull-out path—the over pull-out—can contact the middle rail, neither in pull-out direction nor in insertion direction, with formation of a frictional engagement. According to the invention, instead of the frictional engagement, rolling friction occurs on the lateral guide roller. The pull-out rail according to the invention is thus never unchangeable in its relative position to the middle rail during the inserting: Coming from the position of the over pull-out, it reaches the position of the normal pull-out always without co-movement of the middle rail. This co-movement occurs only in the position of the normal pull-out when the rear end of the pull-out rail is situated between the differential roller and the roller associated with it. In addition, a tilting to the other opposite pull-out rail, fastened to the pull-out furniture part, is thus prevented, both are moved similarly and simultaneously. In the installation—or respectively use position, the lateral guide rollers press the pull-out rails quasi against the respectively other opposite pull-out rail. To great advantage, the pull-out rail thus lies at three contact points to the middle rail. These three contact points are formed by the contacting of an upper and of a lower roller of the middle rail on the respectively associated tracks of the pull-out rail and by contacting of the lateral guide roller according to the invention on a main surface of the pull-out rail orthogonally to the two first-mentioned rollers and thus laterally in an end region of the pull-out rail. The three contact points are thus both spaced apart from one another axially and also configured differently with regard to their orientation in space. The invention therefore understands the rear end region of the pull-out rail to be the region of the pull-out rail which is situated in the open position between the front roller of the middle rail and its actual end. Preferably, this is understood to be the region of the pull-out rail which is situated in the over pull-out in the axial region around the rear roller.

According to the invention, provision is preferably made here that the lateral guide roller forms the axially rearmost contact point, the upper roller is arranged closer at the front end of the pull-out rail, and the lower roller is arranged further closer at the front end of the pull-out rail. This ensures that the pull-out rail always still contacts securely in its maximum pull-out position—the over pull-out—and is secured against a vertical tilting by the two rollers. According to the invention, the lateral guide roller is thus arranged in as great proximity as possible structurally to the upper roller. Hereby, it is ensured that on an over pull-out of the pull-out rail beyond the rear upper roller, a lateral guidance of the pull-out rail is still always present. In a further development of the invention, two lateral guide rollers, spaced apart from one another axially, are provided in the region of the rear end of the pull-out rail. This is particularly secure with regard to the avoidance of a frictional engagement between pull-out rail and middle rail and improves the mobility of the pull-out rail with respect to the middle rail.

The radial distance between the two sides of the circumferences of the upper roller and of the lower roller, assigned to one another, and the lateral guide roller according to the invention is less than 5 cm here, preferably less than 3 cm, even more preferably less than 1.5 cm.

In further development of the invention, provision is made that the middle rail has a lower front roller in a front end region and a lower rear roller in a rear end region of the middle rail, such that the front roller contacts the pull-out rail in the open position, and the rear roller contacts the pull-out rail in the closed position, respectively spaced apart from a front or respectively rear end of the pull-out rail. This leads advantageously to a secure guidance of the pull-out rail over the entire pull-out path.

In configuration of the invention, provision is made that the middle rail has a front upper roller, the rotation axis of which, viewed along the pull-out path, is arranged in front of the rotation axis of the lateral guide roller.

Finally, in further development of the invention, provision is additionally made that the lateral guide rollers are structurally identical, in particular also the rollers are structurally identical with respect to one another. This advantageously simplifies the construction and production and also maintenance of the differential pull-out guide.

The invention is explained further more closely with the aid of the figures of the drawing, wherein parts of identical construction are provided with the same reference numbers. There are shown here in detail:

FIG. 1: lateral view of a differential pull-out guide according to the invention, in closed position,

FIG. 2: lateral view of a differential pull-out guide according to the invention, in open position,

FIG. 3: an individual illustration of the three rails of the differential pull-out guide according to the invention;

FIG. 4: a perspective view of the differential pull-out guide according to the invention in an intermediate position with incipient differential effect;

FIG. 5: an open position of the differential pull-out guide according to the invention and

FIG. 6: a perspective view from below.

FIG. 1 shows a differential pull-out guide 1 according to the invention, in a closed position. The side of the differential pull-out guide 1 pointing to a furniture part which is able to be pulled out can be seen. A body rail 3 has a main surface 18, on which two secondary surfaces 19, 20 are arranged. The upper secondary surface 19 has an upper track 6, the lower secondary surface 20 has a lower track 7.

A middle rail 5 runs in the body rail 3 on its upper rollers 8 and lower rollers 9. The middle rail 5 has a differential roller 11. This transfers a portion of the load of the pull-out rail 4 directly to the corpus rail 3. The differential roller 10 preferably has a play in vertical direction. The middle rail 5 has, in the region above the differential roller 10, an upper roller 8, offset somewhat forward with respect to the latter, which upper roller in the open position supports the rear end of the pull-out rail 4 against a pivoting upward.

The pull-out rail 4 runs between lower contact points 12 of the upper rollers 8 and upper contact points 11 of the lower rollers 9 of the middle rail 5, and is thus guided between these (see FIG. 3). It has a main and a secondary surface 18, 19, the latter carries the two tracks 6, 7 of the pull-out rail (see FIG. 3). The pull-out furniture part which is to be fastened would be fastened directly on the main surface of the pull-out rail 4, however this could also have a lower horizontal web as second secondary surface, on which the pull-out furniture part would then lie in a fastened manner.

In the closed position, the rails 3,4,5 are pushed together maximally, wherein the front ends of these rails are aligned. The middle rail 5 is configured shorter than the other two rails and thus leaves a space at the rear end in particular for an automatic retraction device. Fastening possibilities 21 can be seen in the pull-out rail 4 and in the body rail 3, which are configured primarily as through-openings with or without an internal thread, and which serve for the fastening of a pull-out furniture part on the pull-out rail 4 and the differential pull-out guide on a furniture body. The furniture parts are not illustrated.

FIG. 2 shows a differential pull-out guide 1 according to the invention in its open position—the over pull-out—with maximally pulled-apart rails 3, 4, 5. In the part of the body rail 3 illustrated on the right, the components such as stop means for path delimitation, self-retraction means, blocking devices, etc., are situated, which are initially not relevant for the invention and are therefore not described more closely.

In the middle rail 5, the differential roller 10 can be seen, which runs in the lower track 7 of the body rail 3. In the open position, the lower contact point 12 of the differential roller 10 is situated at a front end of the lower track 7 of the body rail 3. An upper roller 8 is associated with the differential roller 10. This upper roller contacts with its lower contact point 12 the upper track of the pull-out rail 4 and, with its upper contact point 11, the upper track 6 of the body rail 3 at its end. The differential roller 10 and associated upper roller 8 define for the pull-out rail 4 the position of the normal pull-out, in which the rear end of the pull-out rail 4 is situated between both rollers.

It can be further seen that the lower roller 9 of the middle rail 5, contacting the pull-out roller 5 further forward, contacts this in the region between the rear end of the pull-out rail and its centre, preferably rather in the region of its longitudinal centre. This increases the load bearing capability of the differential rail according to the invention. The front stops, which prevent a further pulling out of the pull-out rail 4, can not be seen in FIG. 2. The middle rail 3 has the lateral guide roller 13 according to the invention, which enables a lateral guidance of the pull-out rail 4 in the last region of the pull-out path before and on reaching the open position. A further assisting roller 13′ can be provided between the lateral guide roller 13 according to the invention and the front lower roller 9 (see FIG. 3).

Provision is made that over preferably 100% of the pull-out path, always at least one lateral guide roller 13, 13′ and 13″ is operative, at least however over the last 10% in the region of the open position. Preferably, two lateral guide rollers are operative over 100% of the pull-out path.

FIG. 3 shows an individual illustration of the three rails 3, 4 and 5 with the previously mentioned features. It can be seen that the middle rail 5 consists of a canted profile, on which the rollers 8,9 are fastened in a mounted manner, in particular mounted on one side. In this embodiment, the pull-out rail 4 and the body rail 3 are of equal length. In the closed position, they terminate flush with one another both at their front ends and also at their rear ends. It would also be conceivable to configure the body rail 3 to be shorter than the pull-out rail 4, so that the latter, in the closed position, would be offset forward with respect to the rear end of the pull-out rail.

The two lateral guide rollers 13, 13′ are particularly relevant, of which the rear lateral guide roller 13, illustrated on the left side, is essential to the invention. This ensures the secure lateral guidance of the pull-out rail 4 in the last region of the pull-out path 14 on-load, preferably assisted by the one situated axially before. “on-load” means, vice versa, that the pull-out rail and the middle rail of the differential pull-out guide according to the invention in the non-installed state are connected to one another so loosely and with so much play that the pull-out rail does not necessarily always have to touch the lateral guide roller 13 according to the invention, however always does this on-load, therefore in the installed state with a fastened and in particular laden drawer.

The three lateral guide rollers 13, 13′ and 13″ ensure as a whole a lateral guidance of the pull-out rail 4 over the entire pull-out path. Owing to its arrangement, the lateral guide roller 13 which is essential to the invention leads to the pull-out rail 4 not being able to contact the middle rail with the formation of a frictional engagement. This prevents the shared, rigid displacing of both rails, mentioned in the introduction, so that the desired differential function is always able to be carried out.

On the right-hand side in the region of the upper rollers 8, the middle rail 5 also has a stop means 22, however this is not in accordance with the invention and is therefore not described further. In turn, the fastening possibilities 21 can be seen in the body rail 3 under the pull-out rail 4, which serve for fastening the invention on a body and on a pull-out furniture part, such as a drawer.

FIG. 4 shows a position of the differential pull-out guide 1 according to the invention in the normal pull-out position, in which the differential effect begins or respectively ends. A rear end 17 of the pull-out rail 4 lies between the differential roller 10 and the upper rollers 8 associated therewith. In an insertion direction, the pull-out rail 4 will cover twice the path of the middle rail 5. In the detail views marked by the letters A, B, the lying of the differential roller 10 on the lower track 7 of the body rail 3 and the lying of the associated upper rollers 8 on the upper track of the pull-out rail 4 are illustrated. An inlet bevel 24 of the pull-out rail 4 can also be seen.

FIG. 5 shows the open position—the over pull-out—of the differential pull-out guide 1 according to the invention. In this position, an upper roller 8 of the middle rail 5 contacts a rear end region of the upper track of the pull-out rail 4, which according to the invention is also contacted by the assisting roller 13. The partially cut detail illustration B clearly shows in the enlargement 3:1 that the lateral guide roller 13, just as the other lateral guide rollers, has a rotation axis, tilted by 90°, compared to the rotation axes of the upper rollers 8, thereby it is aligned parallel to a main surface of the middle rail 5. The lateral guide roller 13 and the additional assisting roller 13′ in the detail illustration A thereby contact a main surface of the pull-out rail 4. The assisting roller 13 according to the invention additionally ensures that the pull-out rail 4 is always moved coaxially to the middle rail 5 and no angle forms between the two, which would lead to a canting of the pull-out rail 4.

In FIG. 6 there is shown finally the installation situation of the assisting roller 13, which is in accordance with the invention and relevant to the invention, from a perspective view from below.

It can be seen that the middle rail 5 has a recess 25 through which the lateral guide roller 13 passes. Furthermore, two fastening openings 26 can be seen for the mounting of a lateral guide roller mount 27, into which the latter is held in a force-fitting or form-fitting manner. The lateral guide roller mount 27 contains the axle bearings of the lateral guide roller 13.

Provision is advantageously made that all the lateral guide rollers 13, 13′ and 13″ are configured identically in construction, in particular consist of the same material, which on the one hand simplifies the warehousing and the exchange, and on the other hand entails uniform rolling characteristics. The lateral guide roller 13 is relevant in particular for the avoidance of the disadvantages on over pull-out, however its effect is amplified in further development of the invention through the lateral guide roller 13′.

List of Reference Numbers

• • 1 differential pull-out guide
  • 2
  • 3 body rail
  • 4 pull-out rail
  • 5 middle rail
  • 6 upper track
  • 7 lower track
  • 8 upper roller
  • 9 lower roller
  • 10 differential roller
  • 11 upper contact point
  • 12 lower contact point
  • 13 lateral guide roller
  • 14 pull-out path
  • 15 pull-out direction
  • 16
  • 17 rear end pull-out rail
  • 18 main surface body rail
  • 19 upper secondary surface
  • 20 lower secondary surface
  • 21 fastening possibilities
  • 22 stop means
  • 23
  • 24
  • 25 recess
  • 26 fastening opening
  • 27 lateral guide roller mount