Air vent

Abstract: The present invention relates to an air vent for a motor vehicle passenger compartment, and in particular to an air vent with an air grill that can be rotated to a closed position. A housing 1 has a first pivot bearing 11,12, to which is connected a carrier 20 with a second pivot bearing 25. An air grill 30 with vanes 31-37,38-40 has generally spherical peripheral surfaces and is connected to the second pivot bearing. The air grill 30 may then be rotated about two orthogonal axes within the housing to vary the direction of the air flow entering the passenger compartment. The central vane 34 has a circular periphery, and the air grill 30 may also be rotated to a position in which this vane makes a seal with a compliant sealing section 9 within the housing 1 to close off the flow of air through the air vent.

Description: The present invention relates to an air vent for a motor vehicle passenger compartment. An air vent may have an air grill with vanes or louvres, and be substantially spherical in shape and held in a surrounding annular housing. Such an air vent may be rotated to vary the direction of the air supplied through the vanes to the passenger compartment over substantially a half-sphere. In one arrangement, disclosed in EP 0 622 257, an air grill is held within a tubular housing between two orthogonal pairs of pivots. The air grill has a circular periphery in a plane perpendicular to the axis of the housing, but does not have a circular periphery in a plane parallel to this axis. Therefore, this air grill may not be rotated within the housing to a restrict or close off the air flow. In another arrangement, disclosed in DE-U-7 514 301, a single or cross-wall vane is rotatable in universal joint fashion inside a socket. The vane can be rotated by a limited amount either side of a central position to change the direction of the airflow. The limit of rotation is defined by the contact of an inner projection of the vane with a radially circumferential ring groove behind the socket, at which point the airflow is closed. It is an object of the present invention to provide a generally spherical air grill which may be rotated to restrict or close off the air flow. According to the invention there is provided an air vent for controlling air flow to the passenger compartment of a motor vehicle, the air vent comprising a housing with a first pivot bearing therein, a carrier with a second pivot bearing thereon and a rotatable air grill with vanes to control the direction of air flow through the air vent, in which the carrier is connected within the housing to the first pivot bearing for rotation about a first axis, and in which the air grill is connected to the second pivot bearing for rotation about a second axis, characterised in that the first pivot bearing is provided on a central sealing surface of the housing, the air grill having a generally spherical envelope and at least one vane being a sealing vane with a substantially circular periphery so that the air grill may be rotated to a position in which the or each sealing vane makes a seal with the sealing surface to restrict or close off the flow of air through the air vent. The term envelope is used to mean a continuous surface which extends between and incorporates the peripheral points of the air grill. If the sealing vane is a central vane, then this may have a radius equal to the radius of the generally spherical envelope. One or more vanes may also have a planar surface profile and have surfaces which are parallel with surfaces on other vanes. The housing may advantageously have inner dimensions matched to those of the peripheral surfaces of the air grill. The air grill may then be rotated to a position in which at least one vane acts as a sealing vane to make a seal with the housing around substantially the whole periphery of the vane, to restrict a flow of air through the air vent. In a preferred embodiment of the invention, there is just one sealing vane, which is a central vane in the air grill and which has a radius equal to or greater than the radius of the generally spherical envelope. In order to maximise the efficiency of the seal by reducing any gaps in the seal, the housing may have a compliant surface for making an air tight seal with the sealing vane. The compliant surface may have an inner dimension which is just less than the outer dimension of the sealing vane. Then, when the vane is rotated to make contact with the compliant surface, the peripheral surface of the vane will be pressed into the compliant surface and so close any small gaps to make a good seal. The friction in such a compliant fit will also hold the air grill in the sealed orientation and so maintain the seal. The compliant surface may also be provided with a locating feature, such as a groove, into which the sealing vane may engage and locate into place. The compliant surface may be substantially in the shape of a ring arranged on an inner-facing surface of the housing, and may also be discontinuous in the vicinity of the first pivot bearing. In order to have the convenience of orthogonal axes of adjustment, the first axis should be at right angles to the second axis. These axes may both also be arranged to pass through the centre of the air grill so that the air grill is adjustable about its centre point. One or more of the vanes may also be arranged to be perpendicular to the second axis. In order to provide the maximum adjustment range for the direction of the air supplied to the passenger compartment, the air grill may rotate through at least 180° about at least one axis, centered about a mid-plane through the housing. The direction of the air supplied to the passenger compartment may then be varied over a range of up to a half-sphere. At the extremes of adjustment at 0° and 180° along one of the axes, which is preferably an axis parallel to the sealing vane, the sealing vane may make the seal with the housing. In order to provide a useful adjustment range about the other axis, which is preferably an axis perpendicular to the sealing vane, the air grill should rotate over an adjustment range of at least 60° centered about a mid-plane through the housing. The compliant surface may be formed from any resilient or rubber-like material, such as a synthetic rubber or elastomeric material, which resists scratching or other potential damage from rubbing against the air grill. Other parts of the air vent, for example the air grill, carrier and housing may be formed from plastics materials, for example by injection moulding. In order to aid adjustment of the air vent by hand, at least one of the vanes may incorporate a grip feature to make it easier to rotate the air grill to the desired orientation. The grip feature may advantageously comprise a moulded grip on a central vane and, optionally, with adjacent vanes being shaped to facilitate access to the grip. The compliant seal may be attached to the housing by gluing or by ultrasonic or rf welding techniques. However, in a preferred embodiment the compliant seal and the rest of the housing are formed in a two-step injection mould process. The duct may conveniently be made from a plastics material or materials with, for example, the duct being formed from a tubular extrusion which is then bonded to the housing. The invention will now be described further by way of example with reference to the accompanying drawings, in which: Figure 1 is a top view of a first embodiment of an air vent housing looking down on a housing pivot bearing; Figure 2 is a top view of a first embodiment of a carrier, prior to insertion of the carrier into the housing of Figure 1; Figure 3 is a top view of an air grill, prior to connection of the air grill to the carrier of Figure 2; Figures 4 and 5 are, respectively, front and isometric views of the first embodiment of the housing; Figures 6, 7, 8 and 9 are, respectively, front, side, top and isometric views of the first embodiment of the carrier; Figure 10 is an isometric view of the air grill; Figure 11 is a cross section view of the air vent, showing the housing, carrier and air grill of Figures 1, 2 and 3, each taken along line XI-XI; Figure 12 is a cross section view of the air vent of Figure 11, taken along line XII-XII; Figure 13 is an isometric view of the top portion of a second embodiment of a carrier; Figure 14 is a top view of the carrier of Figure 13; and Figure 15 is a top view of a second embodiment of the air vent housing. Referring first to Figures 1, 4 and 5, an air vent housing 1 has tubular body 2 with a generally circular cross section. Extending perpendicularly outwards from the body are three coplanar mounting flanges 3 that have apertures 4 through which mounting screws (not shown) may secure the air vent housing within a component such as a motor vehicle instrument panel. One end of the housing body is necked down to an inner section 5 with a reduced diameter to which a matching tubular air duct (not shown) may be connected for the supply of air. The other end opens up to an outer section 6 with a slightly greater inner diameter. Between these two parallel-walled sections 5,6 are two taper sections 7,8 leading to a central sealing section 9 that has an inner diameter intermediate that of the inner and outer sections 5,6. The sealing section 9 is formed from a synthetic rubber material which is a thermo-plastic polyurethane elastomer sold under the trade mark Desmopan. The housing 1 is formed in a two-stage injection mould process, with the main body and flanges first moulded in a plastic material. The body of the housing is formed with a channel into which the polyurethane elastomer is injected in the second stage of the process. The sealing section 9 is divided into two half rings by housing bearing points 11,12, and also has running along its centre line a V-shaped recess 10. Referring to Figures 2, 6, 7, 8 and 9, the carrier 20 has a pivot 26 at each end formed from a cylindrical button 21 surrounded concentrically by a flat cylindrical shoulder 22. As can be seen from the relationship between Figures 1 and 2, the carrier 20 is connected to the housing first by inserting the carrier into the housing so that each button 21 enters a channel 13,14. The channels both taper down to necks 15,16 beyond which are the housing bearing points 11,12. Each shoulder 22 will seat against a matching flat surface 17,18 either side of a channel 13,14. The buttons 21 have a diameter which is too wide to pass through the necks 15,16. There is, however, enough flexibility in the housing 1 to permit the housing to deform sufficiently to allow the buttons 21 to slide along the flat surfaces 17,18 and seat into the apertures at the housing bearing points 11,12, whereupon the carrier 20 is held in a secure pivotal arrangement within the housing. Once the carrier 20 is connected to the housing 1, the carrier may be rotated freely through 360° about a pivot axis defined by the housing bearings 11,12. The structure of the carrier 20 is symmetric about a plane through an axis defined between the carrier pivots 26 and also through a plane at right angles to this axis midway between the pivots. The carrier divides into two straight parallel flat arms 23 which extend out from opposite sides of both pivots 26 and which therefore join the carrier pivots 26 together. There is a gap 24 between these arms approximately equal to the diameter of the shoulders 22. At a mid-point of each arm is a carrier bearing point 25. An axis defined by these bearings would intersect the carrier pivot axis at right angles and midway between the carrier pivots 26. An air grill 30 is illustrated in Figures 3 and 10. This has seven vanes 31-37 that define six parallel channels 41-46 through the air grill. There are also three transverse vanes 38,39,40 linking the seven parallel vanes 31-37. The central transverse vane 39 lies on a central pivot axis 47 through the air grill. Each of the two other transverse vanes 38,40 are bowed in arcs between the endmost parallel vanes 31,37. All three transverse vanes are partially cut through by two channels 50,51, on either side of the central parallel vane 34. As seen in Figure 3, the channels 50,51 extend far enough through the transverse vanes 38,39,40 to expose to view the central pivot axis 47. These two channels 50,51 have a spacing so that the two arms 23 of the carrier 20 may slot into the air grill 30 to allow the air grill to be connected to the carrier. This is done by first by inserting the arms 23 into the channels 50,51 so that the carrier bearing points 25 enter between two pairs of flanges 53,54 on the central pivot axis 47. Each carrier bearing 25 has an entrance neck through which the pivot axis 47 may snap past into engagement with the bearing, whereupon the grill 30 is held in a secure pivotal arrangement with the carrier 20. If the three transverse vanes were cut all the way through by the channels 50,51, so that the air grill was only held together by its central pivot axis 47, then the air grill would be able to rotate through a full 360°. However, this full degree of freedom is not necessary for most purposes, and the air grill as illustrated in the drawings may rotate ± 30° about the central pivot axis. The degree of rotation is limited by the contact between the innermost end of the channels 50,51 in the bowed transverse vanes 38,40, and end-stop surfaces of the carrier indicated by the numerals 55 and 56, as seen in Figure 7. The degree of rotation of the air grill about this axis may therefore be designed to be less or more than ± 30° depending on the profile of the carrier end-stop surfaces 55,56 and the depth of the channels 50,51 through the bowed vanes 38,40. Once the air grill is assembled with the carrier, the central parallel vane 34 lies in the centre of the gap 24 between the arms 23. In order to help maintain this alignment between these two components, and in particular to reduce stresses imparted by the central pivot axis 47 on the carrier bearings 25, two opposite edges of the central parallel vane 34 rest in a close slidable fit within two grooves 57 in the inner-facing surface of the shoulders 22. This can be seen most clearly from Figures 11 and 12. The air vent may be disassembled in two stages. First the air grill will snap out of the carrier bearings 25 if it is pulled with sufficient force. Then, the body 2 of the housing may be deformed slightly by squeezing the housing at right angles to the axis of the carrier, so that the diameter of the housing along the carrier axis is increased sufficiently to permit the carrier to be disengaged from the housing. After the assembled air vent is incorporated in an instrument panel, the air grill may still be removed from the housing. This may, for example, be necessary in order to clean inside the housing. However, the carrier will remain in place, since the body of the housing will be held securely by screws through the three apertures 4. As may be seen from Figure 3 and 10, the air grill has a grip 58 incorporated along one edge of the central parallel vane 34. The two pairs of vanes 32,33,35,36 either side of the central vane have a circular bight 59 in otherwise circular profiles, so that fingers may more readily manipulate the grip 58. For the same reason, the end vanes 31,37 both have around the central part of their external spherical surface 60, a depression or spherical bight 61. These bights may, optionally, be provided with a textured finish to improve the grip. Since the carrier 20 may rotate 360° about its axis, the air grill 30 may be oriented with the grip 58 facing either inwards or outwards. Although the air grill may not be quite as easy to manipulate with the grip facing inwards, some users may find the air grill more aesthetically pleasing with the circular sides of all the parallel vanes 31-37 projecting sphere-like from the housing. The direction of the air flow entering the passenger compartment may be adjusted in the following manner. The air grill 30 may initially have the grip 58 facing outwards and be set to a median adjustment, so that the air flow directed by the vanes 31-37,38-40 is expelled along the axis of the housing body 2. It is generally preferred if the carrier axis is aligned vertically, in order to obtain the maximum left-right adjustment. The direction may then be adjusted by rotating the air grill about the horizontal and vertical axes. The air flow through the vent may be blocked by rotating the air grill until the central vane 34 is at right angles to the axis of the housing. The external circular edge of the central parallel vane will then be in contact with the sealing section 9 and engaged with the central V-shaped recess 10, which acts as a locating feature to hold the central vane in place. Figures 13, 14 and 15 show a modification of the carrier 70 and the housing 80, which restrict the rotation of the carrier about its axis to 180°. A carrier shoulder 81 has one half with a circular outline, with the other half modified with a rectangular outline including shoulder corners 86 and two parallel straight shoulder sides 87. Housing bearing points, only one of which 82 may be seen, are also modified so that each flat surface 83 matches the modified shoulder 81. In particular, a part-circular edge 84 to the flat surface has an increased radius to match the increased distance of the shoulder corners 86 from the carrier axis. The maximum degree of rotation between the carrier and the housing is then limited to 180° by the contact between a straight edge 85 to the flat surface 83 and one or the other of the shoulder sides 87. Apart from these modifications, the assembly of the air vent is the same as described above. This limitation in the movement of the air grill ensures that the grip 58 on the central parallel vane 34 does not become oriented away from the passenger compartment. Nevertheless, the grip feature will still become inaccessible once the air grill is rotated to make a seal with the sealing section 9 to restrict or shut off the air flow from the vent. However, when this is so, the air grill may still usefully be manipulated through one of the end vanes 31,37, which will have rotated into a prominent position towards the user. An alternative to an integral housing, not illustrated in the drawings, is to mould the housing as two tubular portions which then snap together along a seam. For example, the inner housing section 5 can be formed separately in a one-step injection mould, and the outer and sealing sections 6,9 can be formed together in a two-stage injection mould. This can reduce the tooling and manufacturing costs. The sealing section 9 may, of course, be formed from other materials, and the polyurethane sold under the trade mark Kraton has been found to give good sealing performance. An air vent as described above has an air grill which may be readily manipulated, and which may be quickly rotated to a closed position to restrict the air flow from the air vent. Hence, there is, for example, no need for an additional air volume control means. An air vent constructed according to the invention will therefore have fewer moving parts than are normally associated with a conventional air vent. The exact structure and arrangement of the vanes according to the invention may, of course, be varied according to need or to taste. For example, the transverse vanes may be straight and parallel, rather than bowed as described above. Equivalent sealing arrangements may also be used, for example, a sealing vane with a flexible peripheral tip, perhaps formed from a synthetic rubber, which makes a compliant seal with a rigid sealing surface within the housing. Similarly, the shape of the air grill envelope may deviate from being spherical while still retaining the same functionality as described above. In particular, as long as the envelope of the air grill may be rotated within the housing without interference from the internal surfaces of the housing, and as long as the sealing vane has an external profile which matches the sealing surface in the housing, then the air grill may be rotated to a closed position to restrict or stop the air flow.

Claims: An air vent for controlling air flow to the passenger compartment of a motor vehicle, the air vent comprising a housing (1) with a first pivot bearing (11,12) therein, a carrier (20) with a second pivot bearing (25) thereon and a rotatable air grill (30) with vanes (31-40) to control the direction of air flow through the air vent, in which the carrier (20) is connected within the housing (1) to the first pivot bearing (11,12) for rotation about a first axis, and in which the air grill (30) is connected to the second pivot bearing (25) for rotation about a second axis, characterised in that the first pivot bearing (11,12) is provided on a central sealing surface (9) of the housing (1), the air grill (30) having a generally spherical envelope and at least one vane being a sealing vane (34) with a substantially circular periphery so that the air grill (30) may be rotated to a position in which the or each sealing vane (34) makes a seal with the sealing surface (9) to restrict or close off the flow of air through the air vent. An air vent according to Claim 1, in which a sealing vane (34) has a radius of at least the radius of the generally spherical envelope. An air vent according to Claim 1 or Claim 2, in which the or each sealing vane (34) makes a seal with the housing (1) around substantially the whole periphery of the vane. An air vent according to any preceding claim, in which the sealing surface (9) is a compliant surface for making a seal with the or each sealing vane (34). An air vent according to Claim 4, in which the compliant surface (9) has a locating feature with which the or each sealing vane (34) may engage. An air vent according to Claim 4 or Claim 5, in which the compliant surface (9) is substantially in the shape of a ring. An air vent according to any of Claims 4 to 6, in which the compliant surface (9) is formed from a rubber-like material. An air vent according to any preceding claim, in which the first axis is at right angles to the second axis. An air vent according to any of Claims 3 to 7, or to Claim 8 when this is appendant to any of Claims 3 to 7, in which the or each sealing vane (34) is perpendicular to the second axis. An air vent according to any preceding claim, in which the first and second axes pass through the centre of the air grill (30). An air vent according to any preceding claim, in which the air grill (30) may rotate through at least 180° about the first axis. An air vent according to any preceding claim, in which the air grill (30) may rotate through at least 60° about the second axis. An air vent according to any preceding claim, in which at least one of the vanes (31-40) incorporates a grip feature.

Inventors: EASTWOOD JAMES, EASTWOOD, JAMES
Applicants: FORD FRANCE, FORD MOTOR CO, FORD WERKE AG, FORD FRANCE S. A., FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1996
Main classification: B60H1
IPC codes: B60H1