Patent ES-378969-A1 (ES)
Title: Hydraulically operable locking mechanism for tilt cab vehicles
IPC: B62D33/07
Filed: 1970-04-23
Abstract: A tilt cab fastening device for fastening the cab to the chassis frame of a vehicle includes a pair of housings 8, 10 one of which is attachable to the cab and the other one to the frame a transverse pin 12 secured to one of the housings a hook 20 and a link 22 connecting the hook intermediate its ends to the other housing, the hook having a hook end portion 20a adapted for fastening engagement with the pin, the link being pivotable from a first position - in which the hook is in fastening engagement with the pin - to a second position - in which the hook is longitudinally displaced to a safety position immediately opposite but spaced from the pin a hook spring 51 biasing the hook in the pin-engaging direction relative to the link and actuator means for pivoting the link from its first position to its second position to initially displace the hook longitudinally from its fastening position to its safety position, and for subsequently pivoting the hook relative to the link from the safety position to a full releasing position relative to the pin, wherein the actuator means include a linearly operable actuator member 38, and a bell-crank cam 30 pivotally connected to that end portion of the link that is pivotally connected to the hook and a main spring 40 for biasing the actuator means to pivot the link towards its first position wherein an actuator connecting link 32 is provided between the actuator member and the bellcrank cam, wherein a third spring 52 is provided for biasing the pivotal connection between the cam and the actuator connecting link in a direction to pivot the link towards its first position and wherein the device is provided with means 54, 58 operable to maintain the link in its second position when the housings are in slightly spaced relation and when the hook during its pivotal return motion from the full releasing position is arrested by the pin in an intermediate position between its fully fastening and fully releasing positions, thereby preventing undesired longitudinal movement of the hook in the fastening direction relative to the other housing. In the construction shown the member 38 is operated by a hydraulic motor 46 and to move the hook member from the fastening to the releasing position the motor is operated to move the member 38 to the left, this causes a cam surface of the cam 30 to roll on the bottom wall of the housing 8 to pivot the link 22 downwardly in the clockwise direction to displace the hook downwardly to the safety position relative to the pin 12 continued movement of the actuator member 38 to the left causes a protruding portion 32a of the actuator connecting link 32 to engage a surface of the upper end portion 20b of the hook and pivots the hook in the counterclockwise direction relative to pin 12 to the releasing position movement of the actuator member 38 to the right reverses the operation of the various parts provided the two housings are properly in engagement however if the housings are slightly vertically spaced the lower end portion 20a of hook 20 engages the pin 12 and prevents the proper movement of the hook to the fastening position, and without the means 54, 58 the cam 30 and the link 22 could both continue to move to the positions they occupy when the hook is properly engaged with the pin 12 and give an erroneous impression that the hook was fully engaged with the pin the means 54, 58 which consists of a U-shaped clevis 54 and a clevis member retaining pin 58 extending from the upper end portion 20b of the hook prevent such movement of the cam 30 and link 22. The clevis 54 is pivotally carried by the pivot pin 34 which connects the cam with the actuator connecting link 32 and the pin 58 holds the clevis in a position in which it embraces the upper end portion of the hook, hence when the hook has its lower end engaged with the pin 12 in an incorrect position, the clevis by engaging the upper end portion of the hook prevents movement of the cam and hence of the link 22. Correct operation of the cam is aided by the spring 52. Instead of the spring 51 which as shown is connected between the upper end portion of the hook member and the actuator link means 32, a compression spring surrounding the pin 38 can be provided.