Differential pull-out guide

Abstract

The invention relates to a differential pull-out guide (1) for pull-out furniture parts, having a body rail (3) that can be attached to a furniture body, a pull-out rail (4) that can be attached to a pull-out furniture part and a middle rail (5) arranged between the body rail (3) and the pull-out rail (4) in accordance with claim 1, characterised in that a lateral guide roller (13) of the middle rail (5) is arranged in the pull-out path (14) on the middle rail (5) in such a way that it is in contact with a rear end region (16) of the pull-out rail (4) in the open position.

Description

[0001] Differential pull-out guide

[0002] The present invention relates to a differential pull-out guide for pull-out furniture parts, which has a carcass rail attachable to a furniture carcass, a pull-out rail attachable to a pull-out furniture part, and a center rail between the two. Each rail has a front end, a rear end, a main surface, and one or more secondary surfaces arranged on this, which are angled to the respective main surface. The carcass rail and pull-out rail each have one or more tracks on which rollers roll during use. The rollers are preferably all arranged on the center rail as upper and lower rollers. The rollers have upper and lower contact points with associated tracks, wherein a contact point is understood to be the area of ​​the roller that contacts a track.Accordingly, when a roller is in use, all areas of the roller circumference become contact points as soon as and as long as they contact the associated track.

[0003] In addition to mounting options for a furniture body, the pull-out rail has a secondary surface on which an upper and a lower track are arranged. The upper track is contacted by the lower contact points of the upper wheels of the center rail. The lower track is contacted by the upper contact points of the lower rollers of the center rail. In other words, the pull-out rail runs between the upper and lower rollers of the center rail and is guided by them.

[0004] The carcass rail has an upper secondary surface with an upper

[0005] The track has a lower secondary surface with a lower track. The upper rollers of the center rail run on the upper track with their upper contact points, and the lower rollers of the center rail run on the lower track with their lower contact points.

[0006] The rollers are used to move the differential extension guide from a closed position to an open position along an extension path in one extension direction. The closed position occurs when the differential extension guide is fully retracted, and the open position occurs when it is fully extended.

[0007] To enable this, the rollers act between the rails and roll along the aforementioned tracks of the rails, allowing the rails to change their relative positions. Typically, all of the rollers are mounted on the center rail for rotation. The center rail also features a differential roller, the function of which is explained below. In addition to the aforementioned rollers, the center rail can feature side guide rollers that provide lateral guidance for the extension rail and whose rotation axis runs parallel to the main surface of the center rail. Thus, a side guide roller is tilted by approximately 90° to a roller, or in other words, oriented orthogonally to it.

[0008] A stop element on the cabinet rail limits the extension path by allowing a stop surface on the center rail to rest against the stop element on the cabinet rail. A similar limit is also found when the rails are pushed together into a closed position.

[0009] When the pull-out rail is extended, the middle rail moves synchronously with the pull-out rail, covering half the distance of the pull-out rail at a time. For this purpose, the middle rail has a load-transferring differential roller that rolls between the tracks of the pull-out rail and the cabinet rail. This differential roller can have a variable axis position relative to the middle rail. The pull-out rail runs between the differential roller and a roller arranged above it. If the end position of the pull-out rail is such that its end is still between the differential roller and its assigned roller, this is referred to as normal extension (also called full extension). If the end position of the pull-out rail is beyond this position, it is referred to as over-extension.This is always desirable and intended when the drawer held between a set of two differential extensions needs to be pulled out of the furniture body more than its nominal installation length and thus be accessible. The center rail is usually shorter than the cabinet rail and shorter than the extension rail. When the differential extension guide is retracted, the rear end of the center rail is offset forward relative to the rear end of the cabinet rail and the rear end of the extension rail.

[0010] Pull-out guides with self-retracting devices are known, in which the pull-out rail is automatically retracted over the final section of the insertion path. These self-retracting devices are often integrated into the pull-out guide, as disclosed, for example, in WO 2008 / 119091 A1.

[0011] Problems with such differential extension guides arise when the furniture components held between them – especially drawers or sliding shelves – are subjected to one-sided force by a user when being pushed in from an over-extension position, also referred to as the open position. This can cause the rear end of the extension rail to contact the center rail, forming a frictional connection, and both rails, rigidly connected to each other, are pushed in further. This leads to misalignment and, in the worst case, to the drawer not being able to be closed. The differential rails on both sides could also be pushed in unevenly, leading to distortion of the device and unnecessary stress on the rollers, as well as closing errors.

[0012] The present invention therefore has the object of providing an improved differential extension guide in which these disadvantages do not occur.

[0013] This object is achieved by the features of claim 1, in particular in that a lateral guide roller of the central rail is arranged in the extension path on the central rail in such a way that in the open position it touches a rear end region of the extension rail, at least in the position of use.

[0014] The lateral contact thus enabled on the main surface of the extension rail means that in the very last section of the extension path - the over-extension - it cannot contact the center rail to form a frictional connection, either in the extension direction or in the retraction direction. According to the invention, rolling friction occurs on the lateral guide roller instead of frictional connection. Thus, the position of the extension rail according to the invention relative to the center rail is never fixed during retraction: Starting from the over-extension position, it always reaches the normal extension position without any movement of the center rail. This movement only begins in the normal extension position, when the rear end of the extension rail is located between the differential roller and its associated track roller.In addition, this prevents any jamming relative to the other, opposite pull-out rail attached to the pull-out furniture part, as both are moved in the same way and simultaneously. When installed or in use, the lateral guide rollers press the pull-out rails against the other, opposite pull-out rail. This greatly advantageously means that the pull-out rail rests on the middle rail at three contact points. These three contact points are formed by the contact of an upper and a lower roller on the middle rail with the respective associated tracks of the pull-out rail and by the contact of the lateral guide roller according to the invention on a main surface of the pull-out rail orthogonal to the first two rollers and thus laterally in an end region of the pull-out rail. The three contact points are therefore both axially spaced from one another and also have different spatial orientations.The invention defines the rear end region of the pull-out rail as the region of the pull-out rail that, in the open position, is located between the front roller of the center rail and its actual end. Preferably, it defines the region of the pull-out rail that, in the over-extension position, is located in the axial region around the rear roller.

[0015] According to the invention, it is preferably provided that the lateral guide roller forms the axially rearmost contact point, the upper roller is arranged closer to the front end of the pull-out rail and the lower roller is arranged even closer to the front end of the pull-out rail. This ensures that the pull-out rail is always securely in contact in its maximum extension position - the over-extension - and is secured against vertical tipping by the two rollers. According to the invention, the lateral guide roller is thus arranged structurally as close as possible to the upper roller. This ensures that if the pull-out rail is over-extended beyond the rear upper roller, the pull-out rail is still laterally guided. In a further development of the invention, two axially spaced-apart lateral guide rollers are provided in the region of the rear end of the pull-out rail.This is particularly safe in terms of avoiding friction between the pull-out rail and the middle rail and improves the mobility of the pull-out rail relative to the middle rail.

[0016] Preferably, the radial distance between the two mutually facing sides of the circumferences of the upper roller and the lateral guide roller according to the invention is less than 5 cm, in particular less than 3 cm, particularly preferably less than 1.5 cm.

[0017] In a further development of the invention, the center rail has a lower front roller in a front end region and a lower rear roller in a rear end region of the center 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, each spaced apart from a front and rear end of the pull-out rail, respectively. This advantageously leads to secure guidance of the pull-out rail over the entire extension path.

[0018] In an embodiment of the invention, it is provided that the center rail has a front upper roller, the axis of rotation of which is arranged in front of the axis of rotation of the side guide roller, seen along the extension path.

[0019] Finally, a further development of the invention provides for the lateral guide rollers to be of identical construction, in particular the rollers to be identical to each other. This advantageously simplifies the design, manufacture, and maintenance of the differential extension guide. The invention is explained in more detail below with reference to the figures of the drawing, in which identical parts are provided with the same reference numerals. In detail:

[0020] Fig. 1 : Side view of a differential pull-out guide according to the invention in the closed position,

[0021] Fig. 2: Side view of a differential pull-out guide according to the invention in the open position,

[0022] Fig. 3: a detailed view of the three rails of the differential pull-out guide according to the invention;

[0023] Fig. 4: a perspective view of the differential extension guide according to the invention in an intermediate position with incipient differential action;

[0024] Fig. 5: an open position of the differential pull-out guide according to the invention and

[0025] Fig. 6: a perspective view from below.

[0026] 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 facing an extendable furniture part is visible. A cabinet 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, and the lower secondary surface 20 has a lower track 7.

[0027] A center rail 5 runs within the cabinet rail 3 on its upper rollers 8 and lower rollers 9. The center rail 5 has a differential roller 11. This transfers part of the load of the extension rail 4 directly to the cabinet rail 3. The differential roller 10 preferably has some play in the vertical direction. In the area above the differential roller 10, the center rail 5 has an upper roller 8 that is slightly offset forward relative to the latter and, in the open position, supports the rear end of the extension rail 4 against upward pivoting.

[0028] The pull-out rail 4 runs between the lower contact points 12 of the upper rollers 8 and the upper contact points 11 of the lower rollers 9 of the center rail 5 and is thus guided between them (see Fig. 3). It has a main surface 18 and a secondary surface 19, the latter supporting the two tracks 6 and 7 of the pull-out rail (see Fig. 3). The pull-out furniture part to be attached would be directly attached to the main surface of the pull-out rail 4, but it could also have a lower horizontal bar as a second secondary surface, on which the pull-out furniture part would rest.

[0029] In the closed position, the rails 3, 4, and 5 are pushed together as far as they can go, with the front ends of these rails aligned. The middle rail 5 is shorter than the other two rails, thus leaving space at the rear end, particularly for an automatic retraction device. Mounting options 21 in the extension rail 4 and the cabinet rail 3 can be seen. These are primarily designed as through-holes with or without an internal thread and serve to attach an extendable furniture part to the extension rail 4 and the differential extension guide to a furniture carcass. The furniture parts are not shown.

[0030] Fig. 2 shows a differential pull-out guide 1 according to the invention in its open position - the over-extension - with the rails 3, 4, 5 pulled apart to the maximum. In the part of the carcass rail 3 shown on the right there are components such as stop means for limiting the travel, self-closing means, locking devices, etc., which are not relevant to the invention and are therefore not described in more detail.

[0031] The differential roller 10 can be seen in the center rail 5, which runs in the lower track 7 of the cabinet rail 3. In the open position, the lower contact point 12 of the differential roller 10 is located at a front end of the lower track 7 of the cabinet rail 3. An upper roller 8 is assigned to the differential roller 10. Its lower contact point 12 makes contact with the upper track of the extension rail 4, and its upper contact point 11 makes contact with the upper track 6 of the cabinet rail 3 at its end. The differential roller 10 and the assigned upper roller 8 define the normal extension position for the extension rail 4, in which the rear end of the extension rail 4 is located between the two rollers.

[0032] It can also be seen that the lower roller 9 of the middle rail 5, which contacts the pull-out rail 5 further forward, contacts the latter in the area between the rear end of the pull-out rail and its center, preferably more in the area of ​​its longitudinal center. This increases the load-bearing capacity of the differential rail according to the invention. Not visible in Figure 2 are the front stops which prevent further extension of the pull-out rail 4. The middle rail 3 has the lateral guide roller 13 according to the invention, which enables lateral guidance of the pull-out rail 4 in the last area of ​​the extension path before and upon reaching the open position. A further auxiliary roller 13' can be provided between the lateral guide roller 13 according to the invention and the front lower roller 9 (see Figure 3).

[0033] It is intended that at least one side guide roller 13, 13' and 13" is always effective over preferably 100% of the extension travel, but at least over the last 10% in the area of ​​the open position. Preferably, two side guide rollers are effective over 100% of the extension travel.

[0034] Fig. 3 shows an individual view of the three rails 3, 4, and 5 with the previously mentioned features. It can be seen that the center rail 5 consists of a folded profile to which the rollers 8, 9 are mounted, in particular mounted on one side. In this embodiment, the extension rail 4 and the cabinet rail 3 are the same length. In the closed position, they are flush with each other at both their front and rear ends. It would also be conceivable to design the cabinet rail 3 shorter than the extension rail 4, so that in the closed position it would be offset forward relative to the rear end of the extension rail.

[0035] Particularly relevant are the two lateral guide rollers 13, 13', of which the rear lateral guide roller 13 shown on the left 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 under load, preferably supported by the one located axially in front of it. "Under load" means, conversely, that the pull-out rail and the center rail of the differential pull-out guide according to the invention are connected to one another so loosely and with so much play in the uninstalled state that the pull-out rail does not necessarily always have to touch the lateral guide roller 13 according to the invention, but always does so under load, i.e., in the installed position with a fastened and, in particular, loaded drawer.

[0036] The three lateral guide rollers 13, 13' and 13" ensure lateral guidance of the extension rail 4 over the entire extension path. Due to its arrangement, the lateral guide roller 13, which is essential to the invention, prevents the extension rail 4 from contacting the center rail, forming a frictional connection. This prevents the aforementioned joint, rigid displacement of both rails, so that the desired differential function can always be performed.

[0037] The center rail 5 also has a stop means 22 on the right side in the area of ​​the upper rollers 8; however, this is not according to the invention and will therefore not be described further. The fastening options 21 in the cabinet rail 3 below the pull-out rail 4 can also be seen, which serve to attach the invention to a cabinet and to a pull-out furniture part such as a drawer.

[0038] Fig. 4 shows a position of the differential pull-out guide 1 according to the invention in the normal extension position, in which the differential action begins and ends. A rear end 17 of the pull-out rail 4 lies between the differential roller 10 and the upper roller 8 assigned to it. In an insertion direction, the pull-out rail 4 will travel twice the distance of the center rail 5. The detailed views marked with the letters A and B show the contact of the differential roller 10 on the lower track 7 of the cabinet rail 3 and the contact of the assigned upper rollers 8 on the upper track of the pull-out rail 4. A lead-in slope 24 of the pull-out rail 4 is also visible.

[0039] Fig. 5 shows the open position—overextension—of the differential pull-out guide 1 according to the invention. In this position, an upper roller 8 of the center 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 auxiliary roller 13. The partially sectioned detailed view B, at a magnification of 3:1, clearly shows that the lateral guide roller 13, like the other lateral guide rollers, has a rotation axis tilted by 90° compared to the rotation axes of the upper rollers 8, thus aligning it parallel to a main surface of the center rail 5. The lateral guide roller 13 and the additional auxiliary roller 13' shown in the detailed view A thus contact a main surface of the pull-out rail 4.The auxiliary roller 13 according to the invention additionally ensures that the pull-out rail 4 is always moved coaxially to the center rail 5 and that no angle is formed between the two, which would lead to the pull-out rail 4 becoming jammed.

[0040] Finally, Fig. 6 shows the installation situation of the auxiliary roller 13 according to the invention and relevant to the invention from a perspective view from below.

[0041] It can be seen that the center rail 5 has a recess 25 through which the lateral guide roller 13 passes. Also visible are two mounting openings 26 for the mounting of a lateral guide roller holder 27, in which the latter is held in a force-fitting or form-fitting manner. The lateral guide roller holder 27 contains the axle bearings of the lateral guide roller 13.

[0042] Advantageously, all lateral guide rollers 13, 13' and 13" are of identical construction, in particular made of the same material, which simplifies storage and replacement on the one hand, and also results in uniform rolling properties. The lateral guide roller 13 is particularly relevant for avoiding the disadvantages of over-extension, but its effect is enhanced by the lateral guide roller 13' in a further development of the invention. LIST OF REFERENCE SYMBOLS

[0043] Differential pull-out guide

[0044] Cabinet rail pull-out rail

[0045] Center rail upper track lower track upper roller lower roller

[0046] Differential roller upper contact point lower contact point Side guide roller Extension path Extension direction rear end Extension rail Main surface Cabinet rail Upper secondary surface Lower secondary surface Mounting options

[0047] Lifting gear

[0048] Recess mounting opening side guide roller bracket

Claims

PATENT CLAIMS 1. Differential pull-out guide (1) for pull-out furniture parts, with a carcass rail (3) that can be attached to a furniture carcass, a pull-out rail (4) that can be attached to a pull-out furniture part, and a middle rail (5) arranged between the carcass rail (3) and the pull-out rail (4), wherein the carcass rail (3) has an upper track (6) and a lower track (7), wherein the pull-out rail (4) has an upper track (6') and a lower track (7'), wherein the middle rail (5) has upper rollers (8), lower rollers (9) and a differential roller (10), wherein these rollers each have an upper contact point (11) and a lower contact point (12),wherein the upper rollers (8) of the middle rail (5) run in the upper track (6) of the carcass rail (3) and contact this with their upper contact points (11) and the lower rollers (9) of the middle rail (5) run in the lower track (7) of the carcass rail (3) and contact this with their lower contact points (12), wherein the upper rollers (8) of the middle rail (5) contact the upper track (6') of the pull-out rail (4) with their lower contact points (12) and the lower rollers (9) of the middle rail (5) contact the lower track (7') of the pull-out rail (4) with their upper contact points (11), wherein the differential pull-out guide (1) along a pull-out path, (14) in a pull-out direction (15) from a closed position, in in which the rails (3, 4, 5) are pushed together to the maximum, can be brought into an open position in which the rails (3, 4, 5) are pulled apart to the maximum, characterized in that a lateral guide roller (13) of the middle rail (5) is arranged in the pull-out path (14) on the middle rail (5) in such a way that in the open position it touches a rear end region (16) of the pull-out rail (4) at least in the position of use.

2. Differential pull-out guide (1) according to claim 1, characterized in that the center rail (5) has a lower front roller (9) in a front end region and a lower rear roller (9) in a rear end region of the center rail (5) such that the front roller (9) contacts the pull-out rail (4) in the open position and the rear roller (9) contacts the pull-out rail (4) in the closed position, each at a distance from a front or rear end of the pull-out rail (4).

3. Differential pull-out guide (1) according to claim 1 or 2, characterized in that the central rail (5) has a front upper roller (8) whose axis of rotation is arranged in front of the axis of rotation of the auxiliary roller (13) as seen along the pull-out path (14).

4. Differential pull-out guide (1) according to claim 1, 2 or 3, characterized in that the mutually facing sides of the circumferences of the upper roller (8) and the lateral guide roller (13) are radially spaced from one another by less than 5 cm, in particular less than 3 cm, particularly preferably less than 1.5 cm.

5. Differential pull-out guide (1) according to one of the preceding claims, characterized in that a further lateral guide roller (13') is provided, which contacts the rear end (16) of the pull-out rail (4) in the open position.

6. Differential pull-out guide (1) according to one of the preceding claims, characterized in that the lateral guide rollers (13, 13', 13") are of identical construction, in particular the rollers (8, 9) are also of identical construction.

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