Force assist arrangement for a flap of an automobile

Abstract

The invention relates to a force assist arrangement for a flap (20) of an automobile (1), comprising a rope (41) connectable to one of the flap (20) and a body (10, 11) of the automobile (1); a rope guide (142) for rolling-up the rope (41); and a spring arrangement (43) urging the rope guide (142) towards a closed position of the flap (20); wherein the rope (41) is substantially unwound from the rope guide (142) when the flap (20) is open, wherein the rope (41) is substantially wound on the rope guide (142) when the flap (20) is closed, wherein the rope guide (142) is connected to a rotatable shaft (144) for common rotation, wherein the shaft (144) is rotatably connected to a support member (145, 160). A small-sized force assist arrangement for a flap and an automobile that provides a force supporting the user in closing the flap is created in that a threaded spindle rod portion (144t) is assigned to the shaft (144), that a spindle nut (152) is axially displaceable along the threaded spindle rod portion (144t), that the spindle nut (152) is configured to compress the spring arrangement (43) when the flap (20) is lowered responsive to a rotation of the threaded spindle rod portion (144t), and that an upward movement of the flap (20) is supported by the spindle nut (152) being loaded by the spring arrangement (43).

Description

[0001] Force assist arrangement for a flap of an automobile

[0002] The invention relates to a force assist arrangement for a flap of an automobile, which allows to assist the user in particular in closing a flap of the automobile such as a tail gate.

[0003] DE 199 16 092 A1 describes a force assist arrangement for a flap of an automobile, comprising a rope connectable to one of the flap and a body of the automobile and a rope guide configured as pulley for rolling-up the rope. A spring arrangement urging the rope guide towards a closed position of the flap is configured as volute spring and is arranged at a level of the top of the flap, wherein the rope is substantially unwound from the rope guide when the flap is open, and wherein the rope is substantially wound on the rope guide when the flap is closed. The rope comprises an abutment portion configured to abut against a receiving portion provided on the body of the automobile, wherein the abutment portion and the receiving portion commonly support the flap in the openend position, where rolling-up the abutment portion on the rope guide entails play of the rope. The volute spring generates a torque sufficient to roll-up the rope, but the assistance for the user is neglectable. The rope needs to be rolled-up several times around the rope guide which has a large diameter, such that the resulting package can only hardly be accomodated within one of flap or body. In the open position of the flap, the rope is very distant from the articulation of flap, such that merchandises nearby cannot be put on the flap from the side.

[0004] EP 1 331 341 B1 shows a force assist arrangement for a flap, comprising a rope connectable the flap of an automobile and a rope guide for rolling-up the rope connectable to the body of an automobile, wherein a spring arrangement configured as coiled spring urges the rope guide to roll-up towards a closed position of the flap. When the flap is open, the rope is substantially unwound from the rope guide, while when the flap is closed, the rope is substantially wound on the rope guide. Here, the rope guide is connected to a rotatable shaft for common rotation, wherein the shaft is rotatably connected to a support member. The spring arrangement comprises a first end supported against a support area of the support member and a second end supported against a drive area of the shaft. The spring arrangement is arranged in a spring housing arranged on the body of the automobile, while a distal end of the rope is attached to a mount bolt on the flap. The rope is surrounded by a telescopic protective housing.

[0005] JP S64 43181 U describes a force assist arrangement for a flap of an automobile, comprising a rope connectable to the body of the automobile, further comprising a rope guide for rolling-up the rope and a spring arrangement urging the rope guide towards a closed position of the flap. The rope has a distal end connected to the flap which is substantially unwound from the rope guide when the flap is open and is substantially wound on the rope guide when the flap is closed. The rope guide is part of a rotatable shaft for common rotation, wherein the shaft is rotatably connected to a support member configured as a bracket. The spring arrangement comprises a first end supported against a support area of the support member, and a second end supported against a drive area of the shaft configured as a groove. Two guide plates are connected to a key portion of the shaft to delimit the rope guide laterally.

[0006] US 2018 019 5332 A1 describes a force assist arrangement for a flap of an automobile, comprising a rope connectable to the body of the automobile and a rope guide configured as a pulley for rolling-up the rope. A spring arrangement is provided to urge the rope guide towards an rolled-up configuration of the rope by rotating the pulley about a fixed axis supporting the pulley. The rope is substantially unwound from the rope guide when the flap is open, and is substantially wound on the rope guide when the flap is closed. The spring arrangement comprises a first end supported against a support area and a second end supported against a drive area of the pulley. It is the object of the invention to provide a small-sized force assist arrangement for a flap and an automobile that provides a force supporting the user in closing the flap.

[0007] This object is achieved according to the invention by a force assist arrangement and an automobile having the features defined in an independent claim.

[0008] According to an aspect of the invention, a force assist arrangement for a flap of an automobile is provided, the force assist arrangement comprising a rope connectable to one of the flap and a body of the automobile; a rope guide for rolling-up the rope; and a spring arrangement urging the rope guide towards a closed position of the flap; wherein the rope is substantially unwound from the rope guide when the flap is open, and wherein the rope is substantially wound on the rope guide when the flap is closed. The rope guide is connected to a rotatable shaft for common rotation, wherein the shaft is rotatably connected to a support member. The force assist arrangement further distinguishes in that that a threaded spindle rod portion is assigned to the shaft, that a spindle nut is axially displaceable along the threaded spindle rod portion, that the spindle nut is configured to compress the spring arrangement when the flap is lowered responsive to a rotation of the threaded spindle rod portion, and that an upward movement of the flap is supported by the spindle nut being loaded by the spring arrangement. The force that can be stored in the displaced spindle nut is considerable, and accordingly, the torque support for closing the flap is high. The force assist arrangement is easy to assemble and unexpensive in design. The spring member can be selected among easily available spring models.

[0009] In a preferred configuration, the threaded spindle rod portion is provided as an extension or a portion of the shaft. This results in a common rotation and rotation speed of the threaded spindle rod portion and the shaft, and is easy to manufacture.

[0010] Preferably, the threaded spindle rod portion has an outer threaded circumference portion having a high pitch, such that the displacement of the spindle nut is high even if a low number ot rotations of the shaft is achieved. The pitch should not be too high, as this could entail blocking of the system.

[0011] In an alternative configuration, the threaded spindle rod portion is driven by the shaft via a gear arrangement. This allows the two parts to be arranged in parallel or at an angle with respect to each other.

[0012] The gear arrangement may be selected from the group comprising a planetry gear, intermeshing gear wheels, bevel gearing. Such gear arrangement may entail a gear ratio different from 1 , with the positive effect that the spindle rod may be axially displaced further than in the coaxial solution.

[0013] The spring arrangement suitably comprises a first spring member configured as a helical spring. Such helical spring allows to generate significant torque. If necessary or desired, the spring arrangement may comprise a second spring member also configured as a helical spring. The second spring member preferably is surrounded by the first spring member, and both preferably surround the shaft.

[0014] The shaft, in a preferred embodiment, comprises a prismatic contur portion and is received in a fitting opening of the rope guide for common rotation. This couples shaft and rope guide.

[0015] In a further refinement, a cylindric contur portion of the shaft can rotate in an eye of an attachment unit to the one of the flap and the body. This leads to a defined rotation axis and creates a bearing for the shaft.

[0016] The attachment unit preferably comprises a housing receiving a bracket. The bracket, as a part of the housing, allows to bear the rotatable shaft. The housing protects the force assist arrangement from external water and dust. It is easy to assemble.

[0017] The attachment unit preferably comprises a roller bearing having an external ring member arranged in a recess of the bracket and an internal ring member receiving a cylindric contur portion of the shaft. The bearing member provides for easy rotational bearing and reduces friction when the shaft and / or the rope guide are rotated.

[0018] The attachment unit preferably comprises a thrust bearing adjacent to the face of the bracket facing away from the rope guide, the thrust bearing having at least one recess for receiving an end of the spring arrangement. Such thrust bearing helps to keep the springs of the spring arrangement distant from each other and from the moved parts. In particular, tilting out of helical springs is efficiently avoided.

[0019] The attachment unit preferably receives the spring arrangement coaxially to the shaft. In a further preferred embodiment, the spring arrangement comprises a first helical spring concentically arranged around the shaft, and a secong helical spring concentically arranged around the first helical spring. Other springs can also be used.

[0020] The attachment unit preferably comprises the spindle nut driven by the threaded spindle rod portion. Thus, all moved parts of the force assist arrangement are housed within the housing, except for the rope guide and its associated parts, protecting these from the view of the passengers and avoiding undesired accidents by interference with fingers of a user.

[0021] In a preferred embodiment, it is possible that a second threaded spindle rod portion is assigned to the shaft, that a second spindle nut is axially displaceable along the second threaded spindle rod portion, wherein the first and second spindle nuts are preferably configured to commonly compress the spring arrangement when the flap is lowered responsive to a rotation of the threaded spindle rod portion, and that an upward movement of the flap is supported by the first and second spindle nuts being loaded by the spring arrangement. The force that can be stored in the spring assembly being compressed from both ends is considerable, and accordingly, the torque support for closing the flap is high. Additionally, the pitch of the threaded spindle rod portion can be reduced in that configuration due to the double path of both spindle nuts. This avoids any rist of tilting within the gearing mating of threaded spindle rod portion and spindle nut.

[0022] It has to be understood that the first and second spindle nuts are displaced toward each other when the flap is lowered, thus compressing the spring arrangement from both sides, and that the upward movement of the flap is supported by the first and second spindle nuts being loaded by the spring arrangement to move away from each other. Such configuration may require threaded spindle rod portions with opposite threads, such that a rotation of the shaft induces opposite axial movements of the spindle nuts. As an alternative, several threaded spindle rod portions may be coupled to the shaft and each support a dedicated spring arrangement and spindle nut, such that the spindle nuts may each load a different spring arrangement, the spring arrangements commonly loading the flap.

[0023] The energy for supporting the upward movement of the flap is preferrably stored in a spring arrangement being compressed and pushing the spindle nut back. As an alternative, the energy for supporting the upward movement of the flap may also be stored in a spring arrangement being expanded and pulling the spindle nut back into its starting position.

[0024] In a particularly interesting configuration, the spring arrangement comprises a first spring member being compressed and a second spring member being extended by the same spindle nut, such that one displacement of the spindle nut results in a load being stored in both spring members.

[0025] Preferably, a first lever and a second lever are arranged adjacent an axial face of the rope guide, wherein the first lever and the second lever each comprise a fitting opening for the shaft, and wherein the first lever and the second lever are commonly rotating with the rope guide. This configuration ensures that the levers are always oriented in the same direction as the shaft and as the rope guide, excluding any rotational play between these parts.

[0026] According to another aspect of the invention, a force assist arrangement for a flap of an automobile is provided, the force assist arrangement comprising a rope connectable to one of the flap and a body of the automobile; a rope guide for rolling-up the rope; and a spring arrangement urging the rope guide towards a closed position of the flap; wherein the rope is substantially unwound from the rope guide when the flap is open, and wherein the rope is substantially wound on the rope guide when the flap is closed. The rope guide is connected to a rotatable shaft for common rotation, the shaft is rotatably connected to a support member, and that the spring arrangement comprises an end supported against a drive area of the shaft. Further, a first lever and a second lever are arranged adjacent an axial face of the rope guide, wherein the first lever and the second lever each comprise a fitting opening for the shaft, and wherein the first lever and the second lever are commonly rotating with the rope guide. This configuration ensures that the levers are always oriented in the same direction as the shaft and as the rope guide, excluding any rotational play between these parts. The force assist arrangement is extremely compact and at the same time very firm, and allows to load the spring arrangement while pivoting down the flap, which load assists a user in pivoting up the flap again.

[0027] The spring arrangement preferably comprises a first end supported against a support area of the support member, the first end being opposite a second end of the spring arrangement that is supported against the drive area of the shaft.

[0028] Preferably, the drive area of the shaft comprises the spindle nut.

[0029] According to a preferred developpment, the spring arrangement comprises a first spring member configured as a helical spring. Helical springs are easy to produce, not expensive and have spring characteristics that are quite reproducible. The helical spring is particularly suitable for imparting a rotational torque. A further improvent is provided in that the first spring member comprises several convolutions around the exterior lateral area of a cup-shaped cylinder. The cup-shaped cylinder prevents the first spring member from tilting or deforming when being loaded, such that the complete load of the rotative deformation of the first spring member can be provided to assist a user in closing the flap.

[0030] In a still improved embodiment, the spring arrangement comprises a second spring member configured as a helical spring. The second spring member can be arranged coaxially with the first spring member, but preferably the two spring members independently act on the shaft. For this purpose, the two spring members can be arranged nested the one into the other, in particular in a concentric manner, such that the outcome is a high torque achieved in a compact space. Both spring members are loaded in the same direction of the flap movement and accordingly, their respective torques can be added.

[0031] Preferably, the second spring member comprises several convolutions within the interior lateral area of a cup-shaped cylinder. The cup-shaped cylinder with its exterior cylinder wall prevents the second spring member from jamming or deforming differently than intended to provide a torque for closing the flap.

[0032] According to another aspect of the invention, a force assist arrangement for a flap of an automobile is provided, the force assist arrangement comprising a rope connectable to one of the flap and a body of the automobile; a rope guide for rolling-up the rope; and a spring arrangement urging the rope guide towards a closed position of the flap; wherein the rope is substantially unwound from the rope guide when the flap is open, and wherein the rope is substantially wound on the rope guide when the flap is closed. The rope guide is connected to a rotatable shaft for common rotation, the shaft is rotatably connected to a support member, the spring arrangement comprises an end supported against a drive area of the shaft. Further, the spring arrangement comprises a first spring member configured as a helical spring. Helical springs are easy to produce, not expensive and have spring characteristics that are quite reproducible. The helical spring is particularly suitable for imparting a rotational torque and / or an axial load. The spring arrangement also comprises a second spring member configured as a helical spring. The second spring member can be arranged coaxially with the first spring member, but preferably the two spring members independently act on the shaft or a member coupled to the shaft. For this purpose, the two spring members can be arranged nested the one into the other, in particular in a concentric manner, such that the outcome is a high torque achieved in a compact space. Both spring members are loaded in the same direction of the flap movement and accordingly, their respective torques and / or loads can be added. The force assist arrangement is extremely compact and at the same time very firm, and allows to load the spring arrangement while pivoting down the flap, which load assists a user in pivoting up the flap again. For example, the member coupled to the shaft can be an extension of the shaft, or, preferably, a spindle nut directly or indirectly driven by the shaft.

[0033] The spring arrangement preferably comprises a first end supported against a support area of the support member, the first end being opposite a second end of the spring arrangement that is supported against the drive area of the shaft.

[0034] Preferably, the drive area of the shaft comprises the spindle nut.

[0035] Preferably, a first lever and a second lever are arranged adjacent an axial face of the rope guide, wherein the first lever and the second lever each comprise a fitting opening for the shaft, and wherein the first lever and the second lever are commonly rotating with the rope guide. This configuration ensures that the levers are always oriented in the same direction as the shaft and as the rope guide, excluding any rotational play between these parts. Further, the first and second levers transmit the forces of the rope to the shaft such that the rope guide can be of light-weight design.

[0036] Preferrably, a cup-shaped cylinder as described above can be arranged between the first spring member and the second spring member such that both spring members are radially separated from each other and are thus prevented from touching each other during operation of the force assist arrangement.

[0037] Further, the cup-shaped cylinder is preferably made from a plastics like polyamide or the like, thus avoiding noise, e.g. when the spring members deform, by avoiding a direct contact.

[0038] In a convenient improvement, the shaft has a prismatic contur and is received in a fitting opening of the rope guide for common rotation. For example, the shaft can have a square cross section, and the opening of the rope guide has a fitting square cross section, or any prismatic cross section allowing the shaft to be coupled to the rope guide in rotation. It is possible, but not preferred, that the rope guide is pressfitted onto the shaft, as the right fitting enables quick assembly.

[0039] In a further refinement, the shaft penetrated into fitting openings of bushings that can rotate in an eye of a first and a second bracket for attachment to the one of the flap and the body. Preferably, the central openings of the bushings have a square or other prismativ cross section configured to receive the shaft substantially without play, such that a rotational movement of the shaft is imparted to the bushings. Same applies for a square opening of the rope guide or of a lever.

[0040] In a preferred embodiment, the cup-shaped cylinder is attached to one of the brackets such that the cup-shaped cylinder form a part of the support that is immovable with respect to e.g. the flap. The cup-shaped cylinder is preferably provided with an eye coaxially to the eyes of the brackets, such that the shaft can also be rotate in said eye using a bushing similar to the bushings mentioned above. Instead of a cup-shaped cylinder, an open cylinder could be provided if the bearing functionality is not needed.

[0041] According to particular preferred improvement, the brackets are connected on a hinge member that allows pivoting of the flap with respect to the body. In this preferred configutation, the hinge allowing pivotal movement of the flap and the force assist arrangement limiting the pivotal angle can be provided in a common unit, thus making assemby easy and avoiding confusion of parts during assembly.

[0042] According to a preferred improvement, the rope guide comprises a circumferential slot for accomodating the rope when the rope in rolled-up while the flap is closed. Preferably, the width of the circumferential slot is configured to receive only one thickness of the rope, such that the wrapping of the rope is in a spiral manner, not screw-like manner.

[0043] In a further development, the first lever and the second lever both comprise a coaxial opening for pivotably receiving a pin portion of a rope terminal of the rope. This ensures that the forces and torques transmitted by the rope are transferred directly from the rope terminal through the levers to the shaft, allowing in particular to use a less rigid and expensive material for the rope guide such as plastic without risking to damage its central bore receiving the shaft. Further, the rope does not need to be attached directly to the rope guide.

[0044] In the preferred configuration of the pin portion being rotatably attached to the levers, the pin portion can take an orientation depending upon the angle the rope takes with respect to the body.

[0045] In a still improved embodiment, the rope terminal comprises a protrusion to which the rope is fixed that is capable to pivot into the slot in such a way that the rope can roll-up more than 360 degrees over the lateral surface of the rope terminal.

[0046] Expediently, the shaft comprises a slotted end allowing the introduction of an end portion of the spring arrangement. As torques and forces of the spring arrangement in general and of the spring members in particular are imparted to the slotted area of the shaft by introducing the respective legs of the spring members into said slot, the slotted area of the shaft can also be designated as drive area. Preferably, the flap can be pivoted downward under the load of gravity, that the spring arrangement is tensioned by the downward pivoting, and that the spring arrangement assists in pivoting upward the flap.

[0047] In a still further improvement, the rotational opening and closing movement of the flap can additionally be supported by a drive. The drive then comprises a motor driving an output shaft, which in turn is configured as a worm member meshing with teeth of e.g. the rope guide. In this configuration, the rope guide is made of steel or another material resisant to wear.

[0048] Preferably, the shaft is secured against axial displacement, e.g. using a security pin or by deforming the shaft to avoid axial displacement. In a more refined configuration, the slotted recess of the shaft traverses a bushing member provided in the central opening in the front side of the cup shaped cylinder, and adjacent both axial sides of said bushing member, a leg of the first and the second spring member tranverse the recess, thus fixing the shaft axially. In further refinement, the shaft then does not comprise a single recess, but rather two holes or recess portions for accomodating the respective legs of the two spring members.

[0049] The rope is preferably a metal cable that is coated with a plastic coating such as a polyamide, thus avoiding corrosion and other frictional noises.

[0050] According to an aspect of the invention, an automobile is provided, comprising a first and a second force assist arrangement as one of those described above as being according to the invention, the first and second force assist arrangements being arranged adjacent to a first and a second hinge coupling the flap to the body.

[0051] In an expedient improvement, the first and second force assist arrangements are arranged within the flap. While space is nearby not available within the body, or arranging a force assist arrangement in the body restricts the available volume for transporting goods, the flap much more convenient in receiving the force assist arrangements, if these are as compact as described above.

[0052] In a still more expedient improvement, a distal end of the rope is connected to the body in such a manner that, in the open position of the flap in which the flap is pivoted away from the body by approximately 90 degrees, the rope is arranged substantially in an angle range between 30 degrees and 60 degrees, preferably in a 45 degree angle with respect to the flap and the body. Accordingly, the rope can take a 45 degree + / - 15 degree angle with respect to one of the flap and the body, and the complementary angle to achieve 90 degrees with respect to the other of the flap and the body.

[0053] When the force assist arrangements are arranged close to or together with the hinge arrangements, the length of the ropes is minimized, and the barrier constituted by the rope small and perturbing any loading operation only to a very low extend.

[0054] It has to be understood that the features refered to as preferred in view of any one of the aspect of the invention do also refer as preferred features of any other aspect of the invention.

[0055] Further improvements, advantages and features will become appearant from the dependent claims as well as from the following description of a preferred embodiment of the invention.

[0056] The invention is subsequently described with reference to the appended drawings with regard to preferred embodiments of the invention.

[0057] Fig. 1 shows a perspective view on parts of an automobile having a liftgate connected to the body via a cable.

[0058] Fig. 2 shows a perspective view on the parts of Fig. 1 from below.

[0059] Fig. 3 shows a perspective view on force assist arrangement and the cable of Fig. 1 and 2. Fig. 4 shows the force assist arrangement of Fig. 3 from another perspective.

[0060] Fig. 5 shows a sectional view along a shaft axis of the force assist arrangement of Fig. 3 and 4.

[0061] Fig. 6 shows an exploded view of the force assist arrangement of Fig. 3 to 5.

[0062] Fig. 7 shows a perspective view on parts of an automobile having a liftgate connected to the body via a cable.

[0063] Fig. 8 shows a perspective view on the parts of Fig. 1 from below.

[0064] Fig. 9 shows a perspective view on force assist arrangement and the cable of Fig. 7 and 8.

[0065] Fig. 10 shows a sectional view along a shaft axis of the force assist arrangement of Fig. 9.

[0066] Fig. 1 1 shows an exploded view of the force assist arrangement of Fig. 9.

[0067] Fig. 1 shows a left body part 10 and a right body part 1 1 of an automobile 1 configured as a pick-up automobile. One can see the cavities 10a and 1 1 a for accomodating the tires. The automobile 1 further comprises a flap 20 configured as a tailgate, which is pivotally connected to the body parts 10, 1 1 using a first and a second hinge arrangement 30. The hinge arrangements 30 each comprises a tailgate-side hinge part 31 and a body-side hinge part (not illustrated) for allowing rotation about a hinge axis 33 defined by an hinge eye 34. The tailgate-side hinge part 31 comprises a proximal first portion 31 a including the hinge eye 34, a lateral second portion 31 b bent by 90° and substantially arranged flush with the upper surface of tailgate 20, and a third distal portion 31 c showing substantially an L-shape, and a fourth portion 31 d being bent by 90° from the distal end of the third distal portion 31 c being substantially parallel to the tailgate 20.

[0068] Each fourth portion 31 d of the tailgate-side hinge parts 31 supports a force assist arrangement 40, to which a rope 41 configured a steel cable with a plastic coating, e.g. made of polyamide, is connected, wherein a distal end 41 d of the rope 41 is connected to respectively one of the body part 10, 11 in such a manner that, in the open position of the flap 20 in which the flap 20 is pivoted away from the body 10, 11 by approximately 90 degrees, the rope 41 is arranged substantially in a 45 degree angle with respect to the flap and the body. The length of the rope 41 connected to force assist arrangement 40 and body parts 10, 11 defines the opening angle of the flap 20, and the length of rope 41 is accordingly configured to exactly achieve an opening angle of 90°. Depending upon the selected location of the connection of the distal end 41 d of the rope 41 and / or of the position, configuration, size of the force assist arrangement 40, the inclination of the rope 41 can vary within a large range, e.g. between 30 and 60 degrees with respect to one of the flap 20 and the body.

[0069] As one particularly can see in Fig. 3 to 6, the force assist arrangement 40 for flap 20 of automobile 1 comprises a rope guide 42 for rolling-up the rope 41 and a spring arrangement 43 urging the rope guide 42 towards a closed position of the flap 20. The rope guide 42 is connected to a rotatable shaft 44 for common rotation, while the shaft 44 is rotatably connected to a support member 45 comprising a first bracket member 45a and a second bracket member 45b.

[0070] One can note that the distal end 41 d of rope 41 can also be connected to the body-side hinge part (not illustrated), thus allowing to configure a ready-to-build- in assembly consisting of the force assist arrangement 40, the rope 41 and the hinge assembly 30. The rope 41 is configured to be substantially unwound from the rope guide 42 when the flap 20 is open, and the rope 41 is substantially wound on the rope guide 42 when the flap 20 is closed.

[0071] The rope guide 42 is substantially disc-shaped and comprises an inner disc portion with a circumference 42b for roling-up the rope 41 , wherein said inner disc portion is axially surrounded on both extremeties respectively by an outer disc portion 42c. The outer disc portion 42c is configured with a V-shaped recess 42v, the bottom of the V-shaped recess 42v having a radial distance to the rotation axis of the rope guide 42 equal to the radius of the circumference 42b. The surfaces of the outer disc portion 42c facing away the inner ring portion comprise a reinforcement ring 42r, which shows, on the upper end in the vicinity of the V-shaped recess 42v, a clearance 42e with parallel surfaces facing each other.

[0072] The shaft 44 has a prismatic contur having a square cross section and is received in a fitting square cross section opening 42a of the rope guide 42 for common rotation. The shaft 44 accordingly traverses the opening 42a. On a distal portion of the shaft 44, a slot like recess 44a is provided in the shaft 44.

[0073] The bracket members 45a, 45b are made of bent sheet metal steel parts of substantially L-shape cross section having two legs, wherein holes 453 for affixing the bracket members 45a, 45b to the fourth portion 31 d of hinge part 31 are provided in a horizontal leg of bracket members 45a, 45b. The first bracket member 45a and the second bracket member 45b each have a cylindrical bore 451 in the vertical leg of the respective bracket member, into whicht bore 451 a bushing member 452 made of plastic, in particular polyamide, is introduced. The bushing member 452 comprises an inner circular portion 452i fitting into the cylindrical bore 451 , an outer circular portion 452o configured as a flange making sure that the bushing member 452 cannot be pushed out of the cylindrical bore 451 . The outer circular portion 452o is accordingly oriented to face the rope guide 42. The central portion of the bushing members 452 is provided with a sqare opening 452c matching the cross section of shaft 44, wherein the bushing members 452 are sufficiently rigid not to be permanently or substantially elastically deformed by a rotation of the shaft 44. Accordingly, responsive to a rotation of the shaft 44, the bushing members 452 rotate within the corresponding cylindrical bore 451 , thus achieving a reproducible rotational operation of all items attached to shaft 44.

[0074] Between the first bracket member 45a and the second bracket member 45b (and their respective bushings members 452) on the one hand and the rope guide 42 on the other hand, a lever member 46 is respectively arranged. The lever member 46 is a flat elongated metal sheet part having a square opening 46a at ist lower end and a cylindrical opening 46b at its upper end. It has to be noted that both lever members 46 are identical in shape, such that in particular the axes of cylindrical opening 46b of both levers 46 are coaxially arranged. The square opening 46a of the levers 46 allows shaft 44 to traverse them and couples the levers 46 in rotation with shaft 44. The thickness of the flat lever member 46 corresponds to the thicknes of reinforcement ring 42r over the exterior surface of outer disc portion 42c, and the width of flat lever member 46 corresponds to the clearance 42e of of reinforcement ring 42r, such that the lever 46 and the axial face of the rope guide 42 mate to become an operational unit.

[0075] A rope terminal 47 having two parallel pins 47a protruding from a flat axial surface 47b comprises a rounded circumference 47c between the surfaces 47b, wherein the thickness of the rope terminal 47 defined by the two axial surfaces 47b corresponds to a width of the inner disc portion, while the pins 47a are configured to rotationally engage the cylindrical opening 46b of the levers 46. More precisely, the levers 46 can either be axially pushed inwardly to engage the rope guide 42 and the pins 47a, or the rope terminal 47 hat its pins 47a engaging the cylindrical opening 46b and the levers 46 are then displaced radially along the clearances 42c. The rope terminal 47 can freely rotate within the cylindrical openings 46b by an angle of at least 180 degrees, wherein the distance of the rounded circumference 47c of rope terminal 47 is configured not to get into frictional contact with circumference 42b of the inner disc portion. The rope terminal 47 comprises a radial rope attachment 47d pointing upwardly in Fig. 6, to which a proximal end of the rope 41 can be affixed, either in a releasable manner or preferably in a permanent manner. As a result, the rope guide 42 with connected rope terminal 47 allows the rope to adapt its orientation depending upon the force of the rope 41 , without the rope guide 42 being imparted with forces and moments, as these are transferred to the shaft 44 via the levers 46. When the rope is rolled-up, the rope terminal 47 with rope attachment 47d is substantially tangentially oriented. The rounded circumference 47c then prolongates the circumference 42b of the inner disc portion, such that the rope 41 can be wound more that one time around circumference 42b of rope guide 42, e.g. two or three times. In the present embodiment, the length of rope 41 is between 0.9 and 1 .8 times the 360° circumference 42b, in particular 1 .3 revolutions. The two axial surfaces 47b allow the rope terminal 47 to freely rotate between the levers 46. Futher, the two axial surfaces 47b are configured such that the rope terminal 47 can enter within the space delimited by the outer disc portion 42b, even beyond V- shaped recess 42v. One will understand that V-shaped recess 42v is provided for facilitating the introduction of pins 47a into cylindrical opening 46b of the levers 46, and that accordingly another suitable shape, e.g. a U-shape, can be selected.

[0076] A cup-shaped cylinder 48 forming part of spring arrangement 43 is made of plastic or sheet-metal, in the present case produced of a polyamide, and is attached the distal bracket members 45b, by any suitable manner known to a skilled person. The cup-shaped cylinder 48 comprises a hollow cylindrical circumference wall 48a, the distal end thereof being delimited by a flat axial wall 48b showing a central opening 48c for allowing the slotted portion 44a of the shaft 44 to protrude therethrough. In the present embodiment, the cup-shaped cylinder 48 is provided, at its proximal end, with L-shaped protrusions 48d configured to engage corresponding slots 454 in bracket members 45b, where the legs of the L-shaped protrusions 48d first penetrate the slots 454 and then, subsequent to a (partial) rotation of cup-shaped cylinder 48, are affixed to the bracket members 45b. It is possible to provide for that the two parts 45b, 48 do not disengage again during operation.

[0077] Central opening 48c has a circular shape and acocomodates another bushing member 452 similar to those described above, having a square opening 452c for receiving the square shaft 44 in the region of its slotted recess 44a defining a drive area.

[0078] Spring arrangement 43 in the present embodiment comprises a first spring member 430 configured as a rotational spring having several, e.g. 10 to 15, convolutions, having a first leg 431 bent in an axial direction to engage the second bracket 45b and a second leg 432 bent in a radially inward direction to engage the slotted portion 44a of shaft 44. In the closed position of flap 20, the first spring member 430 is substantially relaxed, even if perhaps not completely relaxed. In the open position of flap 20, the first spring member 430 is substantially loaded by the rotational relative movement of shaft 44 with respect to the brackets 45a, 45b. In order to avoid any buckling, the convolutions of the first spring member 430 are arranged to be supported by externally adjoining the circumference wall 48a of the cup-shaped cylinder 48, thus avoiding any other deformation to be imparted on first spring member 430 than the loading of first spring member 430 in a rotational sense.

[0079] A second spring member 430’ having a somewhat smaller diameter that the first spring member 430 is also configured as a rotational spring having several, e.g. 12 to 18, convolutions, having a first leg 431 ’ bent in an axial direction to engage the second bracket 45b and a second leg 432’ bent in a radially inward direction to engage the slotted portion 44a of shaft 44. In the closed position of flap 20, the second spring member 430’ is also substantially or at least mainly relaxed. In the open position of flap 20, the second spring member 430’ is substantially loaded by the rotational relative movement of shaft 44 with respect to the brackets 45a, 45b. In order to avoid any buckling, the convolutions of the first spring member 430 are arranged to be supported by internally adjoining the circumference wall 48a of the cup-shaped cylinder 48, thus avoiding any other deformation to be imparted on second spring member 430’ than the loading of second spring member 430’ in a rotational sense. It results a very compact design of the spring arrangement 43 and consequently of the total dimensions of force assist arrangement 40, allowing it to be easily accomodated within flap 10. The slotted recess 44a is accordingly the portion of shaft 44 imparting rotational moments from and to the spring members 430, 430’ and thus defining a drive area of the shaft.

[0080] As one can easily conceive, both spring member 430, 430’ are working into the same way - accordingly, certain configurations might be sufficiently imparted upon by one single spring member 430. As one can further easily conceive, a motor can be connected drive the assembly 40, e.g. having a drive axle supporting a worm gear meshing e.g. with extermal teeth radially provided on outer disc portion 42c in order to open or close the flap 20 by unreeling or reeling the rope 41 , simultaneously loading the spring arrangement 43 or being assisted by the spring arrangement 43.

[0081] The invention now operates as follows:

[0082] Starting from a closed position of flap 20, where flap 20 is arranged in a substantially vertical position adjoining the body 10, 11 , the flap 20 can be pivoted about pivot axis 33 to a substantially horizontal open position providing access to a load floor of the automobile 1 . During the opening movement, a force either by manual operation or by motor operation or by the weight of the flap 20 (or combinations thereof) is imparted upon the springs 430, 430’, loading them in the closing direction. The rope 41 ensures by its length configuration that even when being pressed downwards, the flap 20 remains in its horizontal open position, such that no additional abuttment is needed. This is mainly achieved by the fact that the forces acting on the rope 41 , via the rope terminal 47 and the levers 46, is directly held on the shaft 44.

[0083] When the flap 20 is lifted up again, the springs 430, 430’ act against the load of the flap 20 and support the closing pivotal movement. During this pivotal movement, the springs 430, 430’ further urge, via shaft 44 being attached to the springs 430, 430’, to commonly rotate rope guide 42 and levers 46 and subsequently to reel rope 41 on rope guide 42. The rope terminal 47 then rotates within levers 46 to align with circumference 42b of inner ring portion 42a such that the rope 41 can be arranged in a defined way within rope guide 42, avoiding any jamming.

[0084] As one will easily understand, the spring arrangement 43 could also be replaced by a motor driving the rope guide 42, although a combination of a motor and the spring arrangement 43 is preferred. Accordingly, the present disclosure is intended to encompass a solution where a motor is provided instead of the spring arrangement 43, where the motor moves the flap 20 upwardly and downwardly by changing its direction of rotation. Such embodiment could also be realized by having a drive shaft of the motor driving shaft 44, preferably with an intermeshing gear arrangement. Of course, it is possible to provide a flap with force assist arrangement 40 having a motor- driven embodiment on one side of the flap and a force assist arrangement 40 having a spring arrangement 43 on the other side of the flap.

[0085] The invention has been described above with regard to an embodiment where one spring arrangement 43 is provided being attached to the second bracket member 45b. It has to be understood that a second spring arrangement could be attached to another bracket member, e.g. an additional bracket member or preferably the first bracket member 45a, e.g. facing away the second bracket member 45b. In this configuration, the length of the shaft 44 would be somewhat longer, but the forces and moments acting thereron and the amount of spring members would be increased.

[0086] Fig. 7 to 11 show an automobile having a liftgate connected to the body via a cable and being provided with another preferred embodiment of a force assist arrangement. The same items are referred to with the same reference signs already introduced with regard to Fig. 1 to 6. Same applies to substantially the same items in both embodiments. The features differing from the first embodiment, but structurally comparable, are designated by reference signs incremented by 100.

[0087] The automobile 1 configured as a pick-up automobile depicted in Fig. 7 and 8 is substantially the same as the one explained with reference to Fig. 1 and 2, with the exception that another preferred force assist arrangement 140 is provided on each of the fourth portions 31 d of the tailgate-side hinge parts 31.

[0088] As one particularly can see in Fig. 9 to 11 the force assist arrangement 140 for and a spring arrangement 143 urging the rope guide 142 towards a closed position of the flap 20. The rope guide 142 is connected to a rotatable shaft 144 for common rotation, which rotatable shaft 144 will be described later in more detail. The force assist arrangement 140 is partially housed in a housing 160 consisting of an upper housing part 160u and a lower housing part 1601 realized as plastics injection molding parts.

[0089] One can note that the distal end 41 d of rope 41 can also be connected to the body-side hinge part (not illustrated), thus allowing to configure a ready-to-build- in assembly consisting of the force assist arrangement 40, the rope 41 and the hinge assembly 30. The rope 41 is configured to be substantially unwound from the rope guide 142 when the flap 20 is open, and the rope 41 is substantially wound on the rope guide 142 when the flap 20 is closed.

[0090] The shaft 144 comprises different portions along its extension: a distal portion 144d has a prismatic contur having a square cross section and is received in a fitting square cross section opening 142a of the rope guide 142 for common rotation. The shaft 44 accordingly traverses the opening 142a. The front end 144f of the distal portion 144d is provided with a threaded blind boring 144b into which a frontal screw 151 can be inserted. Adjacent to the distal portion 144d is provided a collar portion 144c configured as a collar with cylindrical outer shape, adjacent to which collar portion 144c a cylindric portion 144e is provided having a reduced outer diameter with regard to the collar portion 144c. Adjacent to the cylindric portion 144e is provided a threaded portion 144t defining a threaded spindle rod portion 144t. Adjacent to the threaded portion 144t is provided a proximal portion 144p having a cylindrical contour and the same outer diameter as the cylindrical portion 144e. The shaft 144 is intended to transfer the rotation imparted onto the rope guide 142 to a spindle nut 152 cooperating with the threaded portion 144t.

[0091] The rope guide 142 is substantially disc-shaped and comprises an inner circumferential disc portion with a circumference 142b for rolling-up the rope 41 , wherein said inner disc portion is axially surrounded on both extremeties respectively by an outer disc portion 142c. The rope guide 142 is made of aluminum die casting in order to minimize its mass inertia when the rope 41 brings it into rotation. For the same reason, the rope guide 142 is provided with through-holes 142t to reduce the mass of rope guide 142.

[0092] On both front faces 142c facing away from each other, frames 142f are provided, into which a lever member 46 can respectively be arranged or fitted. The lever member 46 is a flat elongated metal sheet part having a square opening 46a at its lower end and a cylindrical opening 46b at its upper end. It has to be noted that both lever members 46 are identical in shape, such that in particular the axes of cylindrical opening 46b of both levers 46 are coaxially arranged. The square opening 46a of the levers 46 allows square distal shaft portion 144b to traverse them and to couple the levers 46 in rotation with shaft 144. The lever 46 and the axial face 142c of the rope guide 142 mate to become an operational unit. This operational unit is coupled to shaft 144 by screwing screw 151 into bore 144b. In this context, one will have to note that the forces and moments imparted by the rope are transmitted via the levers 46 to shaft 144, such that rope guide 142 can be of lightweight design and in particular may have a rigidity inferior to that of the sheet metal levers 46.

[0093] A rope terminal 47 having two parallel pins 47a protruding from a flat axial surface 47b comprises a rounded circumference 47c between the surfaces 47b, wherein the thickness of the rope terminal 47 defined by the two axial surfaces 47b corresponds to a width of the inner disc portion, while the pins 47a are configured to rotationally engage the cylindrical opening 46b of the levers 46. More precisely, the levers 46 can either be axially pushed inwardly to engage the rope guide 42 and the pins 47a, or the rope terminal 47 has its pins 47a engaging the cylindrical opening 46b and the levers 46 are then displaced radially along the clearances 42c. The rope terminal 47 can freely rotate within the cylindrical openings 46b by an angle of at least 180 degrees, wherein the distance of the rounded circumference 47c of rope terminal 47 is configured not to get into frictional contact with circumference 142b of the inner disc portion. The rope terminal 47 comprises a radial rope attachment 47d pointing upwardly in Fig. 10, to which a proximal end of the rope 41 can be affixed, either in a releasable manner or preferably in a permanent manner. As a result, the rope guide 142 with connected rope terminal 47 allows the rope to adapt its orientation depending upon the force of the rope 41 , without the rope guide 142 being imparted with forces and moments, as these are transferred to the shaft 144 via the levers 46 (at least partially). When the rope is rolled-up, the rope terminal 47 with rope attachment 47d is substantially tangentially oriented. The rounded circumference 47c then prolongates the circumference 142b of the inner disc portion, such that the rope 41 can be wound more that one time around circumference 142b of rope guide 142, e.g. two or three times. It has to be noted that the width of the inner circumferential disc portion with circumference 142b is matching the diameter of the rope 41 , such that the rope can be rolled-up spirally, and a disposition of the rope in several adjacent convolutions on circumference 142b, which may lead to tilting, is avoided.

[0094] In the present embodiment, the length of rope 41 is between 0.9 and 1 .8 times the 360° circumference 142b, in particular 1 .3 revolutions. The two axial surfaces 47b allow the rope terminal 47 to freely rotate between the levers 46. Futher, the two axial surfaces 47b are configured such that the rope terminal 47 can enter within the space delimited by the outer disc portion 142b.

[0095] The housing parts 1601, 160u define at their proximal end a blind hole 160p configured to receive the proximal portion 144p having a cylindrical contour of the shaft 144, which blind hole 160p defines a proximal rotational bearing of the shaft 144 capable to rotate therein. The housing parts 1601, 160u define next to the blind hole 160p an elongate, substantially cylindrical receptacle portion 160r which axially extends to receive the cylindric portion 144e and the threaded portion 144t of the shaft 144 as well as the parts to be described subsequently surrounding these portions. The housing parts 1601, 160u define at their distal end a distal cylindric through hole 160d which has an internal diameter matching the external diameter of the collar portion 144c of shaft 144. The distal cylindric through hole 160d is provided in a front wall 160f of a transverse chamber 160c configured to receive a bracket member 145 to be described later, which transverse chamber 160c adjoins a separation wall 160s adjacent the receptacle portion 160r showing a cylindrical opening 160o. The front wall 160f shows a central circular protrusion protruding outwardly, with an axial front region 160q and a radial step 160r defining a concentric radial wall portion. While the bottom of the transverse chamber 160c in lower housing part 1601 is substantially flat, upper housing part 160u is provided with protrusions entering the lower housing part 1601 and configured to hold the bracket member 145 in the transverse chamber 160c. The upper housing part 160u and the lower housing part 1601 can be assembled by screws and nuts using the holes 160h of both parts 1601, 160u. These can also be used to connect the housing 160 to the hinge member 30. The housing protects the elements arranged therein from humidity and dust, and further avoids resulting operation noise.

[0096] The bracket member 145 of the force assist arrangement 140 is made of bent sheet metal made of steel and has a substantially L-shape cross section, with a radially inner recess 145i facing the rope guide142 and a radially outer recess

[0097] 1450 facing away from the rope guide142. The bracket member 145 comprises a central bore 145b having substantially the same inner diameter as the outer diameter of cylindrical shaft portion 144e.

[0098] The radially inner recess 145i is configured to receive a roller bearing 153 having an inner ring 153i and an outer ring 153o being rotatable with respect to each other by means of a ring of a plurality of balls 153b, wherein the inner ring 153i has a diameter adapted to the outer diameter of the cylindric portion 144e such that the roller bearing 153 supports the shaft 144 in a rotational direction. The received roller bearing 153 is accomodated half beween the axial front region 160q and the radial step 160r of housing 160 and half in the inner recess

[0099] 1451 of the bracket 145, such that the roller bearing 153 is axially and radially fixedly accomodated between the cited elements.

[0100] The roller bearing 153 and the blind hole 160p are aligned with each other and the axis of rotation of the shaft 144. The spindle nut 152 comprises a threaded inner bore 152t mating with the threaded spindle rod portion 144t. When the shaft 144 is rotated in a first rotational direction, the spindle nut 152 is displaced in the direction of the distal front end 144f of the shaft 144, while when the shaft 144 is rotated in a second rotational direction opposite said first rotational direction, the spindle nut 152 is displaced in the direction of the proximal portion 144p of the shaft 144. The pitch of the threaded spindle rod portion 144t is higher than conventional metric threads, such that a significant axial displacement of spindle nut 152 is achieved with few rotations of the shaft 144. The spindle nut 152 comprises three concentric ribs delimiting two annular concentric spaces 152i, 152o that are configured to receive end portions of the spring arrangement 43.

[0101] Arranged adjacent to a side facing away of the roller bearing 153 of the bracket member 145 is provided a thrust bearing 154, which is axially blocked between bracket 145 and separation wall 160s of the housing 160. The thrust bearing 154 comprises three concentric ribs delimiting two annular concentric spaces 154i, 154o that are configured to receive end portions of the spring arrangement 43 and that are facing the respective annular concentric spaces 152i, 152o of the spindle nut 152.

[0102] One can see in Fig. 10 that a spring arrangement 43 in the present embodiment comprises an outer first spring member 430 configured as a rotational spring having several, e.g. 10 to 20, convolutions, and an inner second spring member 430’ having a somewhat smaller diameter than the first spring member 430, being also configured as a rotational spring having several, e.g. 10 to 20, convolutions. The inner second spring member 430’ surrounds the shaft 144 and is held in the inner concentric spaces 152i of the spindle nut 152 and 154i of the thrust bearing 154. The outer first spring member 430 surrounds the second spring member 430’ and the shaft 144 and is held in the outer concentric spaces 152o of the spindle nut 152 and 154o of the thrust bearing 154.

[0103] One can see in Fig. 11 that a bushing member made of plastic, in particular polyamide, can be arranged between the rope guide 142 and the roller bearing 153. Similarly, a seal arrangement 156 can be provided between the bracket 145 and the thrust bearing 154.

[0104] The invention now operates as follows:

[0105] Starting from a closed position of flap 20, where flap 20 is arranged in a substantially vertical position adjoining the body 10, 1 1 , the flap 20 can be pivoted about pivot axis 33 to a substantially horizontal open position providing access to a load floor of the automobile 1 . During the opening movement, a force either by manual operation or by motor operation or by the weight of the flap 20 (or combinations thereof) is imparted to the rope guide 142 and to the shaft 144 affixed thereto. The threaded spindle rod portion 144t, by the rotation of the shaft, displaces spindle rod 152 toward the rope guide 142 and compresses the springs 430, 430’, loading them in the closing direction.

[0106] The rope 41 ensures by its length configuration that even when being pressed downwards, the flap 20 remains in its horizontal open position, such that no additional abutment is needed. This is mainly achieved by the fact that the forces acting on the rope 41 , via the rope terminal 47 and the levers 46, is directly held on the shaft 144.

[0107] When the flap 20 is lifted up again, the springs 430, 430’ act against the load of the flap 20 and support the closing pivotal movement. During this pivotal movement, the springs 430, 430’ further urge spindle nut 152 away from rope guide 142, thus imparting a support torque onto shaft 144. The weight of flap 20 is thus supported by force assist arrangement 140. The rope terminal 47 then rotates within levers 46 to align with circumference 142b of inner ring portion 142b such that the rope 41 can be arranged in a defined way within rope guide 142, avoiding any jamming.

[0108] The rope guide 142 has a slightly smaller diameter than the rope guide 42, such that the rolling-down of the rope 41 results in at least two or more convolutions of the shaft 144.

[0109] The invention has been described above with regard to an embodiment where the rotation of the rope guide 142 is delivered under the load of the flap 20 being lowered. One will easily understand that instead, a motor with an output rotational shaft could be coupled to the shaft 144, such that the flap 20 could be motor driven.

[0110] Accordingly, the present disclosure is intended to encompass a solution where a motor is provided instead of the spring arrangement 43, where the motor moves the flap 20 upwardly and downwardly by changing its direction of rotation. Such embodiment could also be realized by having a drive shaft of the motor driving shaft 144, preferably with an intermeshing gear arrangement. Of course, it is possible to provide a flap with force assist arrangement 140 having a motor-driven embodiment on one side of the flap and a force assist arrangement 140 having a spring arrangement 43 on the other side of the flap 20.

[0111] The invention has been described above with regard to an embodiment where the shaft 144 has a threaded portion provided in an axial extension thereof. It has to be understood that the threaded spindle rod portion could also be arranged e.g. in parallel to the shaft 144, with a gear mechanism being arranged between shaft and spindle rod, such that e.g. a gear reduction can easily be achieved, e.g. with intermeshing gear wheels of different diameter. Such gear reduction could also be achieved when shaft and spindle rod are arranged coaxially, e.g. by a planetary gear. An angle between shaft and spindle rod could be realized using beveled toothed wheels.

[0112] The invention has been described above with regard to an embodiment where the shaft 144 has one threaded spindle rod portion provided in an axial extension thereof. It has to be understood that a second threaded spindle rod portion could also be arranged at another axial position of the shaft 144, such that the spring arrangement is compressed by two spindle nuts from both sides. Such second threaded spindle rod portion would of course have threads opposite the first threaded spindle rod portion such that a rotation of the shaft results in the two spindle nuts being driven oppositely. In any configuration, more than one threaded spindle rod portion can be assigned to the shaft, and more than one spindle nut can be displaced responsive to the rotation of the spindle rod portion and / or shaft.

[0113] The invention has been described above with regard to two different embodiments. It has to be understood that these embodiments can be combined by substitution of their respective features, or by combining them. For example, in the second embodiment, the spring members 430, 430’ could also be guided in a slot, e.g. in the spindle rod portion, to also directly impart a torque onto the shaft 144. Further, a flap 20 could be provided with one force assist arrangement 40 on one side and one force assist arrangement 140 on the other side. In particular, the rope guides of the two embodiments can easily be interchanged to operate in the other embodiment.

Claims

CLAIMS1 . A force assist arrangement for a flap (20) of an automobile (1 ), comprising a rope (41 ) connectable to one of the flap (20) and a body (10, 1 1 ) of the automobile (1 ); a rope guide (142) for rolling-up the rope (41 ); and a spring arrangement (43) urging the rope guide (142) towards a closed position of the flap (20); wherein the rope (41 ) is substantially unwound from the rope guide (142) when the flap (20) is open, wherein the rope (41 ) is substantially wound on the rope guide (142) when the flap (20) is closed, wherein the rope guide (142) is connected to a rotatable shaft (144) for common rotation, wherein the shaft (144) is rotatably connected to a support member (145, 160), characterized in that a threaded spindle rod portion (144t) is assigned to the shaft (144), that a spindle nut (152) is axially displaceable along the threaded spindle rod portion (144t), that the spindle nut (152) is configured to compress the spring arrangement (43) when the flap (20) is lowered responsive to a rotation of the threaded spindle rod portion (144t), and that an upward movement of the flap (20) is supported by the spindle nut (152) being loaded by the spring arrangement (43).

2. The force assist arrangement arrangement according to claim 1 , characterized in that the threaded spindle rod portion (144t) is provided as an extension or a portion of the shaft (144).

3. The force assist arrangement arrangement according to claim 2, characterized in that the threaded spindle rod portion (144t) has an outer threaded circumference portion having a high pitch.

4. The force assist arrangement arrangement according to claim 1 , characterized in that the threaded spindle rod portion (144t) is driven by the shaft (144) via a gear arrangement.

5. The force assist arrangement arrangement according to claim 4, characterized in that the gear arrangement is selected from the group comprising a planetry gear, intermeshing gear wheels, bevel gearing.

6. The force assist arrangement arrangement according to any one opf claims 1 to 5, characterized in that the spring arrangement (43) comprises a first spring member (430) configured as a helical spring.

7. The force assist arrangement arrangement according to claim 6, characterized in that the spring arrangement (43) comprises a second spring member (430’) configured as a helical spring.

8. The force assist arrangement arrangement according to any of the preceding claims, characterized in that the shaft (144) has a prismatic contur portion (144a) and is received in a fitting opening (142a) of the rope guide (142) for common rotation, and that a cylindric contur portion (144c) of the shaft (144) can rotate in an eye of an attachment unit (160) to the one of the flap (20) and the body (10, 11 ).

9. The force assist arrangement arrangement according to claim 8, characterized in that the attachment unit comprises a housing (160) receiving a bracket (145), a roller bearing (153) having an external ring member (153o) arranged in a recess (145i) of the bracket (145) and an internal ring member (153i) receiving a cylindric contur portion (144c) of the shaft (144), a thrust bearing (154) adjacent to the face of the bracket(145) facing away from the rope guide (142), the thrust bearing (154) having at least one recess (154i; 154o) for receiving an end of the spring arrangement (43), that the housing (160) receives the spring arrangement (43) coaxially to the shaft (144), and that the housing (160) receives the spindle nut (152) driven by the threaded spidle rod portion (144t).

10. The force assist arrangement according to any of the preceding claims, characterized in that a further threaded spindle rod portion is assigned to the shaft, and that a further spindle nut is axially displaceable along the second threaded spindle rod portion responsive to a rotation of the shaft.11 . The force assist arrangement according to claim 10, characterized in that the further threaded spindle rod portion is provided as an extension of the shaft, and that the further spindle nut is axially displaceable along the second threaded spindle rod portion.

12. The force assist arrangement according to claim 11 , characterized in that the further spindle nut and the further spindle nut are displaced in opposite directions responsive to the rotation of the shaft.

13. A force assist arrangement for a flap (20) of an automobile (1 ), preferably according to any of the preceding claims, comprising a rope (41 ) connectable to one of the flap (20) and a body (10, 11 ) of the automobile (1 ); a rope guide (42; 142) for rolling-up the rope (41 ); and a spring arrangement (43) urging the rope guide (42; 142) towards a closed position of the flap (20); wherein the rope (41 ) is substantially unwound from the rope guide (42;142) when the flap (20) is open, wherein the rope (41 ) is substantially wound on the rope guide (42; 142) when the flap (20) is closed, wherein the rope guide (42; 142) is connected to a rotatable shaft (144)for common rotation, wherein the shaft (144) is rotatably connected to a support member (45; 145, 160), wherein the spring arrangement (43) comprises an end (432; 432’) supported against a drive area (441 ; 152) of the shaft (44; 144), characterized in that the spring arrangement (43) comprises a first spring member (430) configured as a helical spring, and that the spring arrangement (43) comprises a second spring member (430’) configured as a helical spring.

14. The force assist arrangement according to claim 13, characterized in that the spring arrangement (43) comprises an end (431 ; 431 ’) being supported against a support area (45b) of the support member (45) opposite the end (432; 432’) of the spring arrangement (43) supported against a drive area (441 ; 152) of the shaft (44; 144).

15. The force assist arrangement according to claim 13 or 14, characterized in that the drive area (152) of the shaft (144) comprises a spindle nut (152).

16. The force assist arrangement arrangement according to any of claims 13 to 15, characterized in that the first spring member (430) comprises several convolutions around an exterior lateral area (48a) of a cupshaped cylinder (48), and that the second spring member (430’) comprises several convolutions within the interior lateral area (48a) of a cup-shaped cylinder (48).

17. The force assist arrangement arrangement according to claim 16, characterized in that the cup-shaped cylinder (48) is attached to the support member (45), the support member (45) comprising at least one bracket (45b).

18. The force assist arrangement arrangement according to claim 17, characterized in that the shaft (44) penetrates into fitting openings (452c) of bushings (452) that can rotate in an eye of a first and a second bracket (45a, 45b) for attachment to the one of the flap (20) and the body (10, 11 ).

19. The force assist arrangement arrangement according to any of the preceding claims, characterized in that the shaft (44) penetrated into fitting openings (452c) of bushings (452) that can rotate in an eye of a first and a second bracket (45a, 45b) of the support member (45; 145) for attachment to the one of the flap (20) and the body (10, 11 ).

20. The force assist arrangement arrangement according to any of the preceding claims, characterized in that the shaft (44) has a prismatic contur portion (144a) and is received in a fitting opening (42a; 142a) of the rope guide (42) for common rotation.21 . The force assist arrangement arrangement according to any of the preceding claims, characterized in that a first lever (46) and a second lever (46) are arranged adjacent an axial face of the rope guide (42; 142), that the first lever (46) and the second lever (46) each comprise a fitting opening (46a) for the shaft (44; 144), wherein the first lever (46) and the second lever (46) are commonly rotating with the rope guide (42; 142).

22. A force assist arrangement for a flap (20) of an automobile (1 ), preferably according to any of the preceding claims, comprising a rope (41 ) connectable to one of the flap (20) and a body (10, 11 ) of the automobile (1 ); a rope guide (42; 142) for rolling-up the rope (41 ); and a spring arrangement (43) urging the rope guide (42; 142) towards a closed position of the flap (20); wherein the rope (41 ) is substantially unwound from the rope guide (42;142) when the flap (20) is open, wherein the rope (41 ) is substantially wound on the rope guide (42; 142) when the flap (20) is closed, wherein the rope guide (42; 142) is connected to a rotatable shaft (144) for common rotation, wherein the shaft (144) is rotatably connected to a support member (45; 145, 160), wherein the spring arrangement (43) comprises an end (432; 432’) supported against a drive area (441 ; 152) of the shaft (44; 144), characterized in that a first lever (46) and a second lever (46) are arranged adjacent an axial face of the rope guide (42; 142), that the first lever (46) and the second lever (46) each comprise a fitting opening (46a) for the shaft (44;144), wherein the first lever (46) and the second lever (46) are commonly rotating with the rope guide (42; 142).

23. The force assist arrangement arrangement according to claim 21 or 22, characterized in that the first lever (46) and the second lever (46) both comprise a coaxial opening (46b) for pivotably receiving an pin portion (47a) of a rope terminal (47) of the rope (41 ).

24. The force assist arrangement arrangement according to claim 23, characterized in that the rope terminal (47) comprises a protrusion (47d) to which the rope (41 ) is fixed, and that the rope terminal (47) is capable to pivot around the pin portions (46a) into the slot (42b; 142b) is such a way that the rope (41 ) can roll-up more than 360 degrees over the lateral surface (47c) of the rope terminal (47).

25. The force assist arrangement arrangement according to any of the preceding claims, characterized in that the rope guide (42; 142) comprises a circumferential slot (42b; 142b) for accomodating the rope (41 ), and that a width of the circumferential slot (42b; 142b) is configured to receive only one thickness of the rope (41 ).

26. The force assist arrangement according to any of the preceding claims, characterized in that the flap (20) can be pivoted downward under the load of gravity, that the spring arrangement (43) is tensioned by the downward pivoting, and that the spring arrangement (43) assists in pivoting upward the flap (20).

27. An automobile having a body (10, 11 ) and a flap (20), characterized by a first and a second force assist arrangement (40) according to any of claims 1 to 26, one of the first and second force assist arrangements (140) being arranged adjacent to a first and a second hinge (30) coupling the flap (20) to the body (10, 11 ).

28. The automobile according to claim 27, characterized in that the first and second force assist arrangements (140) are arranged within the flap (20), and that a distal end (41 d) of the rope (41 ) is connected to the body (10,11) in such a manner that, in the open position of the flap (20) in which the flap is pivoted away from the body (10, 11 ) by approximately 90 degrees, the rope (41 ) is arranged substantially in an angle range between 30 degrees and 60 degrees, preferably in a 45 degree angle with respect to the flap (20) and the body (10, 11 ).

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