Automatic door opening mechanism
An automatic door opening mechanism includes a driving source, a transmission assembly, a screw assembly, a clutch assembly, and engaging members. The transmission assembly is driven by the source. The screw assembly includes a nut with a positioning groove and a screw rod connected to an open-close member. The clutch assembly, between the transmission and screw assemblies, includes a retainer, an interactive structure along the nut's outer periphery, a latching structure along the transmission assembly's inner periphery, and rolling balls movably received in the retainer and positioned between the latching and interactive structures. The engaging members, each with an inclined plane corresponding to a rolling ball, are arranged circularly in the positioning groove. When the open-close member causes the transmission assembly, latching structure, and retainer to move together longitudinally relative to the screw assembly, the rolling balls follow the retainer and are lifted radially by the inclined planes.
1 . An automatic door opening mechanism, for driving an open-close member, and comprising:
a driving source;
a transmission assembly, driven by the driving source;
a screw assembly, comprising a nut and a screw rod threadedly engaged with each other, wherein one end of the screw rod is connected to the open-close member, the screw rod comprises a longitudinal direction and a radial direction perpendicular to the longitudinal direction, and the nut comprises a positioning groove;
a clutch assembly, disposed between the transmission assembly and the screw assembly, wherein the nut is engageable with or disengageable from the transmission assembly along the radial direction via the clutch assembly, the clutch assembly comprises a retainer, an interactive structure, a latching structure, and a plurality of rolling balls, each of the rolling balls is movably accommodated in the retainer along the radial direction, the latching structure is disposed encircling along an inner periphery of the transmission assembly, the interactive structure is disposed encircling along an outer periphery of the nut, and the plurality of rolling balls are positioned between the latching structure and the interactive structure; and
a plurality of engaging members, arranged circularly in the positioning groove and positioned along the longitudinal direction by the positioning groove, each of the engaging members comprising at least one inclined plane corresponding to each of the rolling balls;
wherein, when an external force is applied to the open-close member, the open-close member drives the transmission assembly, the latching structure, and the retainer to move together along the longitudinal direction relative to the screw assembly, and the retainer drives the rolling balls to move to make each of the rolling balls be lifted along the radial direction by the inclined plane.
2 . The automatic door opening mechanism according to claim 1 , wherein each of the engaging members comprises a front side and a back side opposite to each other, the back side faces the outer periphery of the nut, two notches are defined on each of the engaging members, each of the notches comprises two inclined planes opposite to each other, each of the rolling balls is positioned between the two inclined planes of each of the notches, and a distance between the two inclined planes of each notch decreases from the front side toward the back side.
3 . The automatic door opening mechanism according to claim 2 , wherein each engaging member further comprises a plurality of outer edges extending between a peripheral edge of the front side and a peripheral edge of the back side, the plurality of outer edges comprise two first outer edges disposed opposite to each other and extending parallel to the longitudinal direction, and one of the notches is defined on each of the first outer edges.
4 . The automatic door opening mechanism according to claim 3 , wherein the clutch assembly further comprises a plurality of auxiliary elastic elements, each auxiliary elastic element elastically supports two of the rolling balls adjacent to each other, each notch extends from one of the first outer edges toward another first outer edge to define a flared opening and an inner edge is disposed in the notch, a width of the flared opening decreases from the first outer edge toward the inner edge, and each auxiliary elastic element elastically supports two of the rolling balls adjacent to each other between the notches of two of the engaging members adjacent to each other.
5 . The automatic door opening mechanism according to claim 1 , wherein the retainer comprises an inner peripheral wall, a plurality of guiding grooves are defined on the inner peripheral wall along the longitudinal direction, and each of the engaging members is guided by each of the guiding grooves to move solely along the longitudinal direction relative to the retainer.
6 . The automatic door opening mechanism according to claim 1 , wherein the nut is elongated and cylindrical shape, and comprises a first positioning portion and a second positioning portion spaced apart along the longitudinal direction and protruding circumferentially from the outer periphery, the positioning groove is defined between the first positioning portion, the second positioning portion, and the outer periphery, wherein each engaging member comprises a plurality of outer edges, the outer edges comprise two second outer edges disposed opposite to each other, the two second outer edges of each engaging member are disposed corresponding to the first positioning portion and the second positioning portion, respectively.
7 . The automatic door opening mechanism according to claim 6 , wherein the screw assembly further comprises two washers, one of the two washers is clamped between the first positioning portion and one of the second outer edges of each engaging member, and another one of the two washers is clamped between the second positioning portion and another second outer edge of each engaging member.
8 . The automatic door opening mechanism according to claim 1 , wherein the clutch assembly further includes a first elastic element and a second elastic element, the nut is elongated and cylindrical shape and sheathes the first elastic element and the second elastic element, the nut comprises a first stop portion and a second stop portion spaced apart along the longitudinal direction and protruding circumferentially from the outer periphery, and the retainer comprises two side surfaces opposite to each other, wherein the first elastic element is elastically supported between the first stop portion and one of the side surfaces, and the second elastic element is elastically supported between the second stop portion and another side surface.
9 . The automatic door opening mechanism according to claim 8 , further comprising two linkage rings, wherein each engaging member comprises a plurality of outer edges, the outer edges comprise two second outer edges disposed opposite to each other, two nicks are respectively defined on the two second outer edges of each engaging member to form two shoulder portions, each engaging member is positioned in the longitudinal direction by the positioning groove via remaining portions of the two second outer edges, and the two linkage rings sheathe the nut, wherein one of the linkage rings abuts against both one of the shoulder portions of each engaging member and one of the side surfaces of the retainer and is elastically supported by the first elastic element, and another one of the linkage rings abuts against both the other shoulder portion of each engaging member and another side surface of the retainer and is elastically supported by the second elastic element.
10 . The automatic door opening mechanism according to claim 9 , wherein each linkage ring comprises an inner peripheral edge, a plurality of recesses is defined on the inner peripheral edge, and the remaining portions of the two second outer edges of each engaging member extend through the recesses of the respective linkage rings.
11 . The automatic door opening mechanism according to claim 1 , wherein each engaging member comprises a back side facing the outer periphery of the nut, and a gap is defined between the back side of each engaging member and the outer periphery of the nut.
12 . The automatic door opening mechanism according to claim 1 , wherein each engaging member comprises a back side and at least one support portion protruding from the back side, each engaging member is supported on the outer periphery of the nut via the at least one support portion, and a gap is defined between the back side of each engaging member and the outer periphery of the nut.
13 . The automatic door opening mechanism according to claim 1 , wherein the interactive structure comprises a protruding portion and at least one recessed portion disposed opposite to each other, and when the plurality of rolling balls are latched between the latching structure and the protruding portion, the nut is engaged with the transmission assembly.
14 . The automatic door opening mechanism according to claim 1 , wherein the interactive structure comprises a protruding portion and at least one recessed portion disposed opposite to each other, and when an external force is applied to the open-close member, causing the transmission assembly, the latching structure, and the retainer to move together along the longitudinal direction, the plurality of rolling balls move with the retainer along the longitudinal direction from the protruding portion toward the at least one recessed portion and are lifted along the radial direction by the inclined planes to make the transmission assembly disengage from the nut.
15 . The automatic door opening mechanism according to claim 1 , further comprising a housing, the housing comprising a limiting portion, wherein the transmission assembly is rotatably disposed in the limiting portion.