OPERATING DEVICE FOR OPERATING A WALL PART

Abstract

 The present invention relates to an operating device for operating a slidable wall part, such as a French door or a sliding door, comprising a transmission unit with a four-rod mechanism, which comprises:
- a guide rail (52) which can be arranged on the slidable wall part in a third direction;
- a first rod (72) which can be guided by the guide rail (52) and is slidable relative thereto in a longitudinal direction of the guide rail (52);
- a second rod (62) which is arranged pivotally between a first rod (72) and a third rod (58);
- wherein the third rod (58) is arranged substantially on or in line with the longitudinal direction of the guide rail for pivoting around a pivot shaft (56); and
- wherein the slidable wall part forms a fourth rod of the four-rod mechanism.
The invention further relates to an assembly of a slidable wall part with such an operating device, and to a method for application thereof.

Description

[0001] The invention relates to an operating device for operating a slidable wall part such as a French door or a sliding door.

[0002] The invention further relates to an assembly of a slidable wall part with such an operating device, and to a method for application thereof.

[0003] With a French door a (living) space can connect to an outside space such as a garden in continuous manner. An increasing number of people appreciate such a connection between home and garden, which creates a spatial perception.

[0004] A traditional French door comprises one or more carriages which can be arranged on an underside of the slidable wall part and which define a first, lying direction, and an operating rod connected to the one or more carriages and extending in a second direction, wherein the second direction extends substantially transversely of the first direction. Such a French door is generally manually operated with a crank mechanism which engages on the operating rod, which is also referred to as espagnolette rod.

[0005] By operating the espagnolette rod using the manually operated crank, the French door can be lifted onto its wheels for the purpose of being able to slide the French door open and closed, or can be lowered for the purpose of fixing the French door. During this lowering, the door can for instance engage with locking protrusions arranged in the jambs of the frame, which provides some burglar-proofing. French doors are nevertheless relatively susceptible to burglary because they can sometimes be lifted from these locking protrusions using suitable material. Such a French door has a considerable mass, partly due to the large amount of glazing. Because of this mass, the lifting and lowering using the manually operated crank mechanism can be physically onerous, particularly for weaker people such as children and the elderly.

[0006] For the purpose of increasing comfort, devices are known wherein the crank is replaced by a first electric motor. This electric motor is arranged in a housing on the French door, and thereby protrudes from the French door, which is often perceived as unattractive. A second electric motor is additionally provided which can slide the French door via a belt drive. This belt drive extends over substantially the whole door width and - even if concealed in an operation cabinet - is also often perceived as unattractive. These known devices have a visually annoying presence and comprise two electric motors.

[0007] DE-U1-203 12 683 forms the closest prior art, and at least the measures of the characterizing part of claim 1 are new. A further prior art is formed by the documents KR-A-2011 0055783, GB-A-507 803 and GB-A-1 001 432.

[0008] An object of the present invention is to provide an operating device for operating a French door, wherein said drawbacks do not occur, or at least do so to lesser extent.

[0009] Said object is achieved according to the invention with the operating device for operating a slidable wall part, such as a French door or a sliding door, according to claim 1.

[0010] The operating rod, which is also referred to as espagnolette rod, is an operating rod known from the prior art which is configured to displace the also known carriages between a rest position, in which the slidable wall part rests on a ground surface, and an operative position in which the slidable wall part is lifted by the carriages and is displaceable thereby.

[0011] The invention provides an operating device which can if desired be retrofitted in an existing French door, and can for this purpose be delivered as build-in kit. Instead of replacing the existing crank with a first electric motor concealed in a housing and arranging a second electric motor for displacing of a lifted French door, the operating device according to the invention provides the option of arranging an electronic control which is largely concealed from view and wherein only one electric motor is moreover necessary for both lifting and displacing the French door. Provided for this purpose is a transmission unit which lifts the slidable wall part in a first driving stage and in a further driving stage displaces the lifted slidable wall part.

[0012] The force exerted in the third direction by the driving connection can be converted in reliable manner to a force directed in the second direction in that the rod mechanism of the transmission unit is a four-rod mechanism, comprising:

• a guide rail which can be arranged on the slidable wall part in the third direction;
• a first rod which can be guided by the guide rail and is slidable relative thereto in a longitudinal direction of the guide rail;
• a second rod which is arranged pivotally between the first rod and a third rod;
• wherein the third rod is arranged substantially on or in line with the longitudinal direction of the guide rail for pivoting around a pivot shaft; and
• wherein the slidable wall part forms a fourth rod of the four-rod mechanism.

[0013] If the driving connection extends according to a preferred embodiment at least beyond the slidable wall part, the driving connection can display a fixed engagement with the slidable wall part and displace the slidable wall part along the driving connection, which can for instance be a spindle.

[0014] According to a further preferred embodiment, the transmission unit comprises a rod mechanism configured to convert a tensile or pressure force applied by the driving connection in the third direction to a tensile or pressure force directed in the second direction. The operating rod, i.e. the espagnolette rod, also extends in this second direction. By transmitting the tensile or pressure force to the operating rod a manually operated crank becomes superfluous and the operating rod can be operated by the operating unit.

[0015] If the driving connection of the operating device is according to a further preferred embodiment configured to at least exert a tensile force on the transmission unit, an advantageous embodiment results wherein the operating rod is in the first driving stage pulled in upward direction, which is the usual direction for lifting a slidable wall part. After lifting, the tensile force exerted by the driving connection in the third direction can be utilized for laterally displacing the slidable wall part.

[0016] A locking of the lifted lifting position of the transmission unit is obtained if the pivoting connection between the first rod and the second rod comprises according to a further preferred embodiment a slotted recess and at least one further slotted recess is provided, wherein in a lifting position of the transmission unit the two slots are aligned with protrusions which are displaceable relative to the slots to a locking position, wherein in the locking position at least one of the protrusions engages with a hook part such that the first rod and the second rod are locked relative to each other. By locking the lifted lifting position the slidable wall part remains supported in mobile situation by the carriages.

[0017] An increased reliability of the locking is obtained if, according to a further preferred embodiment, a further locking member is provided which comprises a hook part which is arranged on the first rod, and which in the locking position of the transmission unit engages with a corresponding protrusion of the second rod and locks the first rod and the second rod relative to each other.

[0018] According to yet another preferred embodiment, the third rod, which is arranged substantially on or in line with the longitudinal direction of the guide rail for pivoting around the pivot shaft, takes an asymmetrical form, wherein the distance between the pivot shaft and the pivoting connection to the second rod is greater than the distance between the pivot shaft and a further pivoting connection, whereby the third rod is directly or indirectly engageable with the operating rod of the slidable wall part. Because of this asymmetrical form, the third rod provides a lever action which intensifies the force exerted by the drive, which force is used to lift the slidable wall part. Owing to the lever action a less powerful electric motor suffices, which can thereby be more compact.

[0019] The reliability of the force conversion by the transmission unit is increased if this transmission unit is supported at least during lifting of a slidable wall part. The operating device therefore further comprises according to a further preferred embodiment a guide unit with at least a curved path wherein at least the pivoting connection, whereby the third rod is directly or indirectly engageable with a lifting rod of the slidable wall part, can be guided. This guide unit can for instance be arranged on a frame in which the slidable wall part is slidable.

[0020] In addition to a guiding of the rod mechanism, the guide unit preferably also provides additional burglar-proofing. The operating device further comprises for this purpose according to yet another preferred embodiment a guide unit with at least a curved path wherein at least the pivoting connection between the third rod and the second rod can be guided, wherein the curved path bounds the pivoting connection on the upper side in a substantially standing position of the third rod. In the substantially standing position of the third rod an imaginary line through the pivoting connection between the third rod and the second rod, and the further pivoting connection of the third rod, whereby the third rod is directly or indirectly engageable with the operating rod of the slidable wall part, extends in the second direction, i.e. the same direction as the operating rod (i.e. espagnolette rod). The third rod is hereby bounded on the upper side in a lowered rest position of the slidable wall part, whereby a thief cannot lift the slidable wall part with for instance a crowbar.

[0021] According to a further preferred embodiment, the driving connection comprises a spindle which can be driven with the drive and which is configured to displace the first rod in longitudinal direction relative to the guide rail. This spindle is preferably provided with a double screw thread so that a relatively great drive force is combined with a relatively high displacement speed correlated to the pitch of the spindle.

[0022] According to a further preferred embodiment, the pitch of the spindle varies, wherein the spindle has a pitch over a first part which is smaller than the pitch of a second part of the spindle. When the drive speed of the drive is constant, the slidable wall part will slide relatively slowly over the first part of the spindle and then slide more quickly over the second part of the spindle. It is hereby possible to achieve that a sliding door, for instance during opening, starts to slide slowly over a first part and then slides more quickly over a second part.

[0023] According to a further preferred embodiment, the drive comprises an electric motor which can for instance form part of a domotic system.

[0024] According to a further preferred embodiment, the drive comprises an (additional) manual operation. Although it is possible to envisage that the operating device is provided only with a manual operation, this operation will preferably be arranged as an addition so that the manual operation can be used as backup in the case of possible motor failure. The system however provides advantages even without electric motor and with only a manual operation, because a conventional crank is superfluous and the manual operation can for instance be provided on or close to a frame, where a crank handle can be connected. A greater lever action can be obtained with such a crank handle than with a hand crank on the French door itself, whereby the French door can also be opened and closed manually by children and the elderly.

[0025] If a tiltable gearbox is according to a further preferred embodiment provided between the drive and the transmission unit and the electric motor is releasably connected to the gearbox, the electric motor can be (temporarily) disconnected in simple manner. A user can hereby employ the manual operation as backup.

[0026] By providing the operating device according to a further preferred embodiment with an auxiliary spring, which is arranged in biased state on the transmission unit and/or on the drive, a bias can be provided which is configured to provide an additional lifting force for lifting the slidable wall part.

[0027] An operating device which is controlled remotely or automatically (via a domotic system) has the drawback that it could cause people or animals to be become jammed between the slidable wall part and the surrounding frame. In order to prevent injury in such cases, the control device further comprises according to a further preferred embodiment a safeguard against becoming caught, provided between the drive and the transmission unit and comprising:

• a drive shaft with a non-round cross-section which corresponds to a non-round recess in the spindle, wherein the drive shaft and the spindle are slidable in longitudinal direction relative to each other;
• a sleeve part with an internal screw thread which corresponds to an external screw thread of the spindle;
• a fixing sleeve arranged in the sleeve part;
• a compression spring arranged in the sleeve part;
• wherein in a driven operative position the compression spring presses against the fixing sleeve and keeps the external screw thread of the spindle out of engagement with the internal screw thread in the sleeve part; and
• wherein, in the event of catching, the compression spring is compressed and the external screw thread of the spindle comes into engagement with the internal screw thread in the sleeve part, wherein the compression spring is compressed further and the spindle tightens into the sleeve part under the spring tension.

[0028] The operating device can be supplied as a kit and can be retrofitted in an already existing slidable wall part. It suffices to arrange only one slotted recess in which parts of the operating device can be received. After assembly with a slidable wall part, an assembly results of a slidable wall part, such as a French door or a sliding door, and an operating device according to the invention, wherein the first direction in which the one or more carriages are provided extends substantially along a lower edge of the slidable wall part, wherein the second direction in which the operating rod extends extends substantially along a side edge of the slidable wall part, wherein the transmission unit is arranged on or close to an upper corner of the slidable wall part and wherein the third direction in which the driving connection extends between the drive and the transmission unit extends substantially along an upper edge of the slidable wall part.

[0029] The invention further relates to a method for operating a slidable wall part, such as a French door or a sliding door, comprising the steps of:

• applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive;
• converting this drive force to a force extending substantially in a standing direction using the transmission unit; and
• operating an operating rod using the converted force, whereby the slidable wall part is lifted from a ground surface relative to one or more carriages arranged thereon, and is mobile.

[0030] According to a preferred embodiment of the method, this further comprises the steps of:

• applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive; and
• locking the lifted position after lifting of the slidable wall part.

[0031] The lifted position of the slidable wall part can be locked by bringing the transmission unit into a locking position.

[0032] According to a further preferred embodiment of the method, this further comprises the steps of:

• applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive; and
• displacing the slidable wall part which is supported and lifted by the one or more carriages.

[0033] According to yet another preferred embodiment of the method, an operating device according to the invention is applied.

[0034] Preferred embodiments of the present invention are further elucidated in the following description with reference to the drawing, in which:

Figure 1 shows a schematic view of a wall with a French door, provided with an operating device according to the invention.

Figure 2 shows a detail view of a drive;

Figure 3 shows a detail view of a safeguard against becoming caught;

Figure 4 shows a detail view of an optional manual operation;

Figure 5 shows a detail view of a transmission unit of the operating device;

Figures 6-9 shows successive steps of the lifting of a slidable wall part 12;

Figure 10 shows a locking step of the operating device;

Figure 11 shows a situation according to figures 6-10, wherein the slidable wall part has been slid;

Figures 12 and 13 show views of the slidable wall part in a lowered situation; and

Figures 14 and 15 show views of the slidable wall part in a lifted and slidable situation.

[0035] Figure 1 shows a wall 1 with a French door 2 provided with an operating device according to the invention. French door 2 comprises a door frame 4 with a fixed wall part 6 and a slidable wall part 12, wherein fixed wall part 6 and slidable wall part 12 in the shown embodiment each comprise a window 8, 14.

[0036] The operating device comprises a drive 20 which in the shown embodiment takes a dual form. In the shown embodiment drive 20 comprises on the one hand an electric motor 42 and on the other an (emergency) manual operation 44 to be further elucidated, which is provided in gearbox 36 in the top left corner. This gearbox 36 comprises a right-angled transmission.

[0037] A driving connection in the form of a spindle 24 runs from gearbox 36 to slidable wall part 12 (in a third direction III, to the right in the figure). This spindle 24 is connected drivably to a transmission unit 50 which is arranged in slidable wall part 12. A conventional operating rod 120, also referred to hereinafter as espagnolette rod 120, can be operated via this transmission unit 50, as will be elucidated further hereinbelow. Espagnolette rod 120 extends downward (in a second direction II) inside slidable wall part 12 from transmission unit 50 and is connected via a conventional guide mechanism 122 to conventional carriages 128, whereby slidable wall part 12 is slidable (in a first direction I) in lifted situation. It is noted that in a conventional manually operated French door the crank engages on espagnolette rod 120. The first direction I and the third direction III define a reciprocal lateral movement and the third direction III defines an up and downward movement (figure 1).

[0038] The operating device according to the invention is configured to operate a conventional espagnolette rod 120 and can therefore be retrofitted in an already existing French door. It suffices for this purpose to arrange a recess in the upper side of slidable wall part 12 in which the operating device can be received, and to further arrange a drive 20 which is in drivable connection with transmission unit 50. This drive 20 runs through a recess already present in door frame 4.

[0039] Drive 20 is shown in more detail in figures 2-4. Electric motor 42 is connected via a sliding coupling 40 and a drive rod 38 to a tiltable gearbox 36. Spindle 24 runs from this gearbox 36, wherein a safeguard against becoming caught 28 is in a preferred embodiment provided between gearbox 36 and spindle 24.

[0040] The safeguard against becoming caught 28 is shown in more detail in figure 3, and comprises a drive shaft 30 on which a gear of gearbox 36 is mounted. Drive shaft 30 is shown both in assembled situation and separately, so as to show that it comprises a non-round form at the outer end remote from gearbox 36. In the shown embodiment the non-round form is hexagonal and engages in an internal corresponding hexagonal recess in spindle 24. When spindle 24 rotates and is stopped, for instance because someone gets his or her body caught between door frame 4 and slidable wall part 12, spindle 24 rotates inward in the sleeve part 33 provided with internal screw thread, and presses here a fixing sleeve 32 counter to the action of a compression spring 34. Sleeve part 33 is mounted on fixed components, for instance via gearbox 36 on door frame 4. When spindle 24 rotates in sleeve part 33, this will become jammed and thus function as safeguard against becoming caught.

[0041] If electric motor 42 were not to function, for instance in the case of a power failure or if electric motor 42 has unexpectedly broken down, it may be desirable to slide the slidable wall part 12 of French door 2 manually so that it can be closed at all times. An (emergency) manual operation 44 is provided for this purpose. Gearbox 36 takes a tiltable form, and electric motor 42 can be disconnected from drive rod 38 by moving sliding coupling 40 upward. Gearbox 36 can then be tilted outward away from wall 1, and a conventional crank handle 46 can be connected to gearbox 36. The operating device can now be driven by turning crank handle 46.

[0042] As shown in figure 5, spindle 24 runs in a guide rail 22 which is screwed fixedly to door frame 4. Spindle 24 engages on a carrier 26 which is provided with a screw thread which corresponds to the external screw thread of spindle 24. Carrier 26 then engages on a wall part carrier 82 on which a fixing rod 72 is mounted.

[0043] Fixing rod 72 is connected pivotally to a fixing plate 62, which is in turn connected pivotally to a rocker 58. This rocker 58 is mounted pivotally on a rocker block 54 by means of a pivot shaft 56. Rocker block 54 is screwed fixedly into slidable wall part 12 and provides a fixed pivot point 56 for rocker 58. Fixing rod 72, slidable wall part 12, fixing plate 62 and rocker 58 together form a four-rod mechanism which is configured to convert a lying force exerted by spindle 24 to an upward force for lifting slidable wall part 12 via the conventional espagnolette bar 120, so that this wall part is supported by wheels 132 of carriages 128 and is slidable with limited resistance.

[0044] It is noted that two fixing plates 62 between which rocker 58 is enclosed are provided in a particularly advantageous and stable embodiment.

[0045] Fixing rod 72, which can be guided by guide rail 52 and is slidable in a longitudinal direction relative to this guide rail 52, forms a first rod of the four-rod mechanism. Fixing plate 62, which is arranged pivotally between fixing rod 72 and rocker 58, forms the second rod of the four-rod mechanism, while rocker 58 forms the third rod. Rocker 58 is arranged substantially on or in line with the longitudinal direction of guide rail 52 for pivoting around a pivot shaft 56. Finally, slidable wall part 12 forms a fourth rod of the four-rod mechanism.

[0046] Successive steps of the lifting of a slidable wall part 12 are elucidated with reference to figures 6-10. Figure 6 shows an enlarged view of the situation of figure 5. Fixing plate 62 is shown transparently with broken lines for the sake of clarity.

[0047] When fixing rod 72 moves in the direction of arrow O (to the left in the figure) a second protrusion 76 arranged on fixing rod 74 presses against fixing plate 62. The first protrusion 74 of fixing rod 72, which is situated in slotted recess 64 of fixing plate 62, will begin to function here as pivot shaft between fixing rod 72 and fixing plate 62. When fixing rod 72 moves in the direction of arrow O, fixing plate 62 is pulled along and this fixing plate 62 pulls on rocker 58. Fixing plate 62 and rocker 58 are connected to a pivot shaft 60. As a result of this tensile force rocker 58 begins to rotate about its fixed pivot point 56, whereby pivot shaft 88 with pull rod 90 also moves upward. Figures 7, 8 and 9 show successive stages. Guide block 70 provides a centering of fixing rod 72 in guide rail 52, which in the shown embodiment is a C-profile.

[0048] It is noted that rocker 58 provides a lever action in that the distance between pivot points 56 and 60 is greater than the distance between pivot points 56 and 88.

[0049] A compression spring 86, which pushes against a brake block 80 which is screwed fixedly onto slidable wall part 12, is optionally provided. In biased situation, compression spring 86 is situated over a spring rod 84 arranged between brake block 80 and wall part carrier 82, whereby this compression spring 86 pushes wall part carrier 82 away from brake block 80 (to the left in the figure) and thus supports spindle 24 in the lifting of slidable wall part 12.

[0050] In figure 9 the situation has been reached in which slidable wall part 12 has been fully lifted and is fully supported by wheels 132 of the carriages (figures 14 and 15). Rocker 58 is now in an end position and protrusions 74 and 76 are situated in line with the respective slotted recesses 64,66.

[0051] In order to keep slidable wall part 12 in the lifted situation and to prevent it descending under the influence of the force of gravity, a locking step is performed. By displacing fixing rod 72 further in the direction of arrow O, protrusions 74 and 76 slide in slots 64, 66 and a locking is created in that the second protrusion 76 of fixing rod 72 hooks behind hook part 67 of second slotted recess 66 of fixing plate 62.

[0052] An optional additional locking can be formed by having a protrusion 68 of fixing plate 62 engage with a corresponding hook part 78 of fixing rod 72. In figure 9 this protrusion 68 still lies in front of hook part 78, and in figure 10 it has been pulled into a locking engagement. It is particularly advantageous for this protrusion 68 to be embodied as a pinion.

[0053] According to a particularly advantageous embodiment, an end guide 106 is provided which has a receiving plate 108 with one or more guide slots. Three guide slots 110, 112, 114 are provided in the shown preferred embodiment. It is noted that two receiving plates 108, between which rocker 58 is enclosed, are provided in a particularly advantageous and stable embodiment.

[0054] Pivot shaft 88 between rocker 58 and pull rod 90 preferably protrudes on one or both sides, so that it forms a guide protrusion with which this pivot shaft 88 guides rocker 58 in the curved guide slot 110. A stable structure is obtained by retaining rocker 58 between two receiving plates 108.

[0055] It is particularly advantageous for pivot shaft 60 between rocker 58 and fixing plate 62 to likewise protrude on one or both sides and thereby form a guide protrusion with which rocker 58 is received in a second curved guide slot 112. In the lowered position shown in figures 5, 6, 12, 13 this second guide slot 112 blocks the protruding pivot shaft 60 of rocker 58, which functions as guide protrusion, on the upper side (figure 6), whereby it provides a burglar-proofing. In figure 6 the second guide slot 112 prevents rocker 58 moving upward, and slidable wall part 12 can thereby not be lifted by a burglar. In the lowered situation the slidable wall part 12 rests on a ground sill 18 and is too heavy to be displaced (figures 12, 13). Conventional locking protrusions, which are also already burglar-resistant to some extent, can be provided if desired.

[0056] By providing the one or more receiving plates 108 with a third guide slot 114, rocker 58 can in the tilted situation shown in figure 10 be slid out of the locking of end guide 106, i.e. toward the partially opened, slid position of slidable wall part 12 shown in figure 11. It is noted that in the opened situation in figure 11 the locking between protrusion 76 and hook part 67 on the one hand and the locking between protrusion 68 and hook part 78 on the other is preserved.

[0057] When transmission unit 50 of the operating device moves in the direction of arrow O, slidable wall part 12 is displaced from the lowered rest position in figures 12, 13 to the lifted and slidable position in figures 14, 15. Espagnolette rod 120 engages with a protrusion 121 on a link 124 of a guide mechanism 122 which is guided through a number of slots 126. When espagnolette rod 120 is pulled upward, carriages 128 with protrusions are displaced through slotted recesses 130, whereby carriages 128 begin to support slidable wall part 12 with their wheels 132. Slidable wall part 12 can now be slid in simple manner, wherein it rolls over wheels 132.

[0058] Although it shows a preferred embodiment of the invention, the above described embodiment is intended solely to illustrate the present invention and not to limit in any way the specification of the invention.

[0059] It is particularly noted that, although the invention is elucidated on the basis of a French door, it can also be applied for other slidable wall parts, such as sliding doors.

[0060] Where measures in the claims are followed by reference numerals, such reference numerals serve only to contribute toward the understanding of the claims, but are in no way limitative for the scope of protection. The rights described are defined by the following claims, within the scope of which many modifications can be envisaged.

Claims

1. Operating device for operating a slidable wall part such as a French door or a sliding door, comprising:

- one or more carriages (128) which can be arranged on an underside of the slidable wall part (12) and which define a first, lying direction (I);

- an operating rod (120) connected to the one or more carriages (128) and extending in a second direction (II), wherein the second direction extends substantially transversely of the first direction;

- wherein a transmission unit (50) is provided in line with the operating rod (120), which unit is connected via a driving connection to a drive (20), and wherein the driving connection extends substantially in a third direction (III) parallel to the first direction;

- wherein the transmission unit (50) comprises a rod mechanism configured to convert a tensile or pressure force applied by the driving connection in the third direction to a tensile or pressure force directed in the second direction.

characterized in that the rod mechanism of the transmission unit is a four-rod mechanism, comprising:

- a guide rail (52) which can be arranged on the slidable wall part in the third direction;

- a first rod (72) which can be guided by the guide rail (52) and is slidable relative thereto in a longitudinal direction of the guide rail (52);

- a second rod (62) which is arranged pivotally between the first rod (72) and a third rod (58);

- wherein the third rod (58) is arranged substantially on or in line with the longitudinal direction of the guide rail for pivoting around a pivot shaft (56); and

- wherein the slidable wall part forms a fourth rod of the four-rod mechanism.

2. Operating device as claimed in claim 1, wherein the pivoting connection between the first rod (72) and the second rod (62) comprises a slotted recess (64) and at least one further slotted recess (66) is provided, wherein in a lifting position of the transmission unit the two slots (64, 66) are aligned with protrusions (74, 76) which are displaceable relative to the slots (64, 66) to a locking position, wherein in the locking position at least one of the protrusions (74, 76) engages with a hook part (67) such that the first rod (72) and the second rod (62) are locked relative to each other.

3. Operating device as claimed in claim 2, wherein a further locking member is provided which comprises a hook part (78) which is arranged on the first rod (72), and which in the locking position of the transmission unit engages with a corresponding protrusion (68) of the second rod (67) and locks the first rod (72) and the second rod (62) relative to each other.

4. Operating device as claimed in any of the foregoing claims, wherein the third rod (58), which is arranged substantially on or in line with the longitudinal direction of the guide rail for pivoting around the pivot shaft (56), takes an asymmetrical form, wherein the distance between the pivot shaft (56) and the pivoting connection to the second rod (62) is greater than the distance between the pivot shaft (56) and a further pivoting connection (88), whereby the third rod (58) is directly or indirectly engageable with the operating rod (120) of the slidable wall part (12).

5. Operating device as claimed in any of the foregoing claims, further comprising a guide unit (106) with at least a curved path (110) wherein at least the pivoting connection (88), whereby the third rod (58) is directly or indirectly engageable with a lifting rod of the slidable wall part (12), can be guided.

6. Operating device as claimed in any of the foregoing claims, further comprising a guide unit (106) with at least a curved path (112) wherein at least the pivoting connection (60) between the third rod (58) and the second rod (62) can be guided, wherein the curved path (112) bounds the pivoting connection (60) on the upper side in a substantially standing position of the third rod (58).

7. Operating device as claimed in any of the foregoing claims, wherein the driving connection comprises a spindle (24) which can be driven with the drive and which is configured to displace the first rod (72) in longitudinal direction relative to the guide rail (52); and

- wherein the drive preferably comprises an electric motor.

8. Operating device as claimed in claim 7, wherein the drive comprises a manual operation; and

- wherein a tiltable gearbox is preferably provided between the drive and the transmission unit and the electric motor is releasably connected to the gearbox.

9. Operating device as claimed in any of the foregoing claims, further comprising an auxiliary spring (86) which is arranged in biased state on the transmission unit and/or on the drive.

10. Operating device as claimed in any of the foregoing claims, wherein provided between the drive and the transmission unit is a safeguard against becoming caught, comprising:

- a drive shaft (36) with a non-round cross-section which corresponds to a non-round recess in the spindle (24), wherein the drive shaft (36) and the spindle (24) are slidable in longitudinal direction relative to each other;

- a sleeve part (33) with an internal screw thread which corresponds to an external screw thread of the spindle (24);

- a fixing sleeve (32) arranged in the sleeve part (33);

- a compression spring (34) arranged in the sleeve part (33);

- wherein in a driven operative position the compression spring (34) presses against the fixing sleeve (32) and keeps the external screw thread of the spindle out of engagement with the internal screw thread in the sleeve part (33); and

- wherein, in the event of catching, the compression spring (34) is compressed and the external screw thread of the spindle comes into engagement with the internal screw thread in the sleeve part (33), wherein the compression spring (34) is compressed further and the spindle (24) tightens into the sleeve part (33) under the spring tension.

11. Assembly of a slidable wall part (12), such as a French door or a sliding door, and an operating device as claimed in any of the claims 1-10, wherein the first direction in which the one or more carriages are provided extends substantially along a lower edge of the slidable wall part, wherein the second direction in which the operating rod extends extends substantially along a side edge of the slidable wall part, wherein the transmission unit is arranged on or close to an upper corner of the slidable wall part and wherein the third direction in which the driving connection extends between the drive and the transmission unit extends substantially along an upper edge of the slidable wall part.

12. Method for operating a slidable wall part (12), such as a French door or a sliding door, comprising the steps of:

- applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive;

- converting this drive force to a force extending substantially in a standing direction using the transmission unit; and

- operating an operating rod using the converted force, whereby the slidable wall part is lifted from a ground surface relative to one or more carriages arranged thereon, and is mobile.

13. Method as claimed in claim 12, further comprising the steps of:

- applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive; and

- locking the lifted position after lifting of the slidable wall part.

14. Method as claimed in claim 12 or 13, further comprising the steps of:

- applying a drive force, which extends substantially parallel to a lying upper edge of the slidable wall part, to a transmission unit of an operating unit using a drive; and

- displacing the slidable wall part which is supported and lifted by the one or more carriages.

15. Method as claimed in any of the claims 12-14, wherein an operating device as claimed in any of the claims 1-11 is applied.

Drawing