A quick-release fitting for lockingly engaging between two inwardly-directed lips of a track may comprise two resilient plates that are spreadable via a blade moved between raised/disengaged and lowered/engaged positions via a four-bar linkage mechanism. The lower edges of the plates may comprise flanges that extend at angles corresponding to the angles of the undersides of the inwardly-directed lips. To concentrate contact forces between the fitting and the track, and reduce a spreading force on the track, the plates may include a neck region immediately above the flanges. The quick-release fitting may also include a roller assembly allowing the structure being supported by the fitting to be tilted rearward and moved. The roller assembly may include features to keep the quick-release fitting aligned with the track when moved.

A track fitting for securing a structure to an open-top channeled track may include at least one leaf having a flange portion that depends at an angle from a levering portion, and at least one fastener for connecting the levering portion to the structure, wherein in a secured condition, the flange portion is oriented for engagement with an underside of at least one of the two inwardly directed lips and the levering portion extends outside the open-top channel where the fastener secures the levering portion to the structure.

A quick-release fitting for lockingly engaging between two inwardly-directed lips of a track may comprise two resilient plates that are spreadable via a blade moved between raised/disengaged and lowered/engaged positions via a four-bar linkage mechanism. The lower edges of the plates may comprise flanges that extend at angles corresponding to the angles of the undersides of the inwardly-directed lips. To concentrate contact forces between the fitting and the track, and reduce a spreading force on the track, the plates may include a neck region immediately above the flanges. The quick-release fitting may also include a roller assembly allowing the structure being supported by the fitting to be tilted rearward and moved. The roller assembly may include features to keep the quick-release fitting aligned with the track when moved.

A track fitting for securing a structure to an open-top channeled track may include at least one leaf having a flange portion that depends at an angle from a levering portion, and at least one fastener for connecting the levering portion to the structure, wherein in a secured condition, the flange portion is oriented for engagement with an underside of at least one of the two inwardly directed lips and the levering portion extends outside the open-top channel where the fastener secures the levering portion to the structure.