Vehicle door-stop device

Abstract: A door-stop device for vehicles comprises: a base structure (12) carrying a pair of rollers (1, 2) that turn about respective axes which are parallel to one another and are elastically pushed against one another; and a metal tie rod (14) having a pair of rolling surfaces (26, 28) set opposite to one another, on which the above-mentioned rollers (1, 2) act, said rolling surfaces (26, 28) presenting at least one positioning notch (32) designed to be engaged by one of said rollers (1, 2) to define a position of stable retention of the door. The aforesaid positioning notch (32) presents: an arched central portion having a radius of curvature R a = (10 to 15) R 1 , where R 1 is the radius of the corresponding roller (1); a pair of arched lateral portions with a radius of curvature R b = (1.1 to 1.8) R 1 , where the aforesaid central portion has an extension, in the direction of the longitudinal axis of the tie rod, A = (0.15 to 0.30) R 1 .

Description: The present invention relates to a door-stop device for vehicles, of the type comprising: a base structure carrying a pair of rollers that turn about respective axes which are parallel to one another and are elastically pushed against one another; and a metal tie rod having a pair of rolling surfaces set opposite to one another, on which the above-mentioned rollers act, said rolling surfaces presenting at least one positioning notch designed to be engaged by one of said rollers to define a position of stable retention of the door. This kind of door-stop device is disclosed in FR-A-2622624 which discloses a door-stop mechanism comprising a retaining device of the pull-rod type, with a housing fastened inside the door in the volume contained between the outer and inner panels. The stop mechanism comprises at least one pair of opposite notches on the pull-rod, which is accommodated between a pair of elastic rollers. A similar solution is described in DE-A-4207650; the door-stop device has one or more spring-mounted deflectable rollers which interlock with the door holder in certain stop positions (notches), wherein the roller is made of or covered with a ceramic material, glass, glass-ceramic or a sintered metal with graphite inserts. One of the problems of the door-stop devices of the type indicated above lies in the fact that these devices, during the movement of opening and closing of the door, present an intrinsic noisiness due to the rolling of the rollers on the corresponding rolling surfaces of the tie rod. Automobile manufacturers set very strict limits on the maximum noise level admitted for such devices. For example, door-stop devices that produce noise levels higher than 52 dB are frequently not considered acceptable. Although numerous solutions have been adopted to reduce the noise levels of the door-stop devices in question, as yet a definitive solution to the problem has not been found. The aim of the present invention is to provide an improved door-stop device that enables a reduction in the noise levels as compared to known devices, at the same time without this involving an increase in the production cost. According to the present invention, the above purpose is achieved by a door-stop device having the characteristics that form the subject of the main claim. The present invention will now be described in detail with reference to the attached drawings, which are provided purely to furnish a non-limiting example, and in which: Figure 1 is a partially sectional plan view of a door-stop device according to the present invention; Figure 2 is a plan view at a larger scale of the part indicated by the arrow II in Figure 1; and Figures 3 and 4 are details at a larger scale of the parts designated by the arrows III and IV in Figure 2. With reference to Figure 1, the number 10 designates a door-stop device for vehicles comprising, in a known way, a base structure 12 designed to be fixed to an oscillating door of a vehicle (not illustrated), and a metal tie rod 14 designed to be connected in an articulated way to an upright of the motor vehicle (not illustrated either). The base structure 12 carries a first roller 1, which is mounted so that it can turn with respect to the base structure 12 about a fixed axis orthogonal to the plane of representation of Figure 1. The base structure 12 moreover carries a torsion bar consisting of a metal bar 16 anchored to the base structure 12 and carrying at one of its ends a second roller 2 which is free to turn about an axis parallel to the axis of the first roller 1 and is elastically pushed towards the first roller 1 by the elastic loading of the spring 16. The metal tie rod 14 carries at one of its ends an articulation element 18 which is designed to be fixed to the upright of a vehicle (not illustrated). The tie rod 14 is articulated to the articulation element 18 by means of a pin 20 that engages a through hole 22 formed at one end of the tie rod 14. The tie rod 14 may be provided with a protection element 24 made of plastic material co-moulded at one end of the tie rod 14, as described in the Italian Patent Application No. T098A000304 of the present applicant. With reference to Figure 2, the metal tie rod 14 presents two rolling surfaces 26, 28 set opposite to one another on which the two rollers 1, 2 roll during the opening and closing movements of the door. The rolling surface 26 ends with a hook-shaped seat 30 which co-operates with the fixed-axis roller 1 to withhold the door of the vehicle in a position of maximum opening. Along the rolling surface 26 is made at least one positioning notch 32 defining a partially open position of the door. Positioning notches 34 are preferably provided also on the rolling surface 28 in positions corresponding to the hook-shaped seat 30 and to the or each positioning notch 32. The present invention has stemmed from the realization that a considerable part of the noise produced by the door-stop device 10 during opening and closing of the door is due to the impact of the rollers 1, 2 against the walls of the positioning notches 32 and, where present, 34. According to the present invention, by appropriately shaping the positioning notches, a considerable reduction is obtained in the noise level of the device. In particular, with reference to Figure 3, the positioning notch 32 is made in such a way as to present an arched central portion having a radius of curvature R a and two arched lateral portions having a radius of curvature R b . The arched lateral portions are radiused to the remaining part of the rolling surface 26 by means of appropriately sized connecting radiuses R c . The central portion with radius of curvature R a has an axial extension designated by A in Figure 3, whilst the depth of the positioning notch 32 is designated by h 1 . According to the present invention, designating by R 1 the radius of the roller 1, the dimensions R a , R b , A and h 1 that enable optimization of the reduction in noise level of the device are as follows: R a = (10 to 15)R 1 R b = (1.1 to 1.8)R 1 R c = (0.15 to 0.30)R 1 h 1 = (0.12 to 0.50)R 1 With reference to Figure 4, the positioning notches 34, where present, preferably have an arched shape with a radius of curvature R d and a depth h 2 , and are radiused to the remaining part of the rolling surface 28 by means of appropriately sized connecting radiuses R e . The dimensional values of R d and h 2 are preferably as follows: R d = (1.1 to 1.6)R 2 h 2 = (0.12 to 0.30)R 2 where R 2 is the radius of the roller 2. In a concrete embodiment, the radiuses R 1 and R 2 preferably have the following values: R 1 = 6.5 mm; R 2 = 7.5 mm. Preferably, the rolling surfaces 26 and 28 should moreover have a mean surface roughness R z = 8 to 16µm. Tests carried out by the present applicant have proved that the conformation of the positioning notches as described above enables a reduction in the noise level of the device to 36-40 dB.

Claims: A door-stop device for vehicles, comprising: a base structure (12) carrying a pair of rollers (1, 2) that turn about respective axes which are parallel to one another and are elastically pushed against one another; and a metal tie rod (14) having a pair of rolling surfaces (26, 28) set opposite to one another, on which the above-mentioned rollers (1, 2) act, said rolling surfaces (26, 28) presenting at least one positioning notch (32) designed to be engaged by one of said rollers (1, 2) to define a position of stable retention of the door, characterized in that said positioning notch (32) presents: an arched central portion having a radius of curvature R a = (10 to 15)R 1 , where R 1 is the radius of the corresponding roller (1); a pair of arched lateral portions with a radius of curvature R b = (1.1 to 1.8) R 1 , where the aforesaid central portion has an extension, in the direction of the longitudinal axis of the tie rod, A = (0.15 to 0.30) R 1 . A door-stop device according to Claim 1, characterized in that the aforesaid positioning notch (32) has a depth h 1 = (0.12 to 0.50)R 1 . A door-stop device according to Claim 1, characterized in that it comprises at least one second positioning notch (34) set in a position opposite to that of the aforesaid positioning notch (32), the second positioning notch (34) having an arched shape with a radius of curvature R d = (1.1 to 1.6)R 2 , where R 2 is the radius of the corresponding roller (2). A door-stop device according to Claim 3, characterized in that the aforesaid second positioning notch (34) has a depth h 2 = (0.12 to 0.30)R 2 . A door-stop device according to Claim 1, characterized in that said rolling surfaces (26, 28) present a mean surface roughness R z = 8 to 16 µm.

Inventors: AUDISIO VITTORIO, AUDISIO, VITTORIO
Applicants: GAMMASTAMP SPA, GAMMASTAMP S.P.A.
Application year: 2000
Main classification: E05C17
IPC codes: E05C17