Suspension mechanism for tracked vehicles

A vehicle having an endless track which is in driving engagement at the front end portion with an engine-driven wheel. A slide rail assembly is provided for engagement with the lower run of the endless track. The suspension mechanism includes a suspension spring assembly which is connected at the front end directly or indirectly with the slide rail assembly. The other end of the spring assembly is connected with the free end of a swingable arm which is pivotably mounted at the other end on the vehicle frame. The intermediate portion of the swingable arm is connected with the rear portion of the slide rail assembly through a linkage including a crank lever.

I claim:

1. Vehicle including frame means, endless track means having front and rear end portions and upper and lower runs, power driven wheel means engaged with the endless track means at the front end portion thereof, slide rail means extending along and engaged with said lower run of the endless track means, suspension spring means including compression spring means and having one end connected with said slide rail means, first link means having one end pivotably connected with the frame means and the other end pivotably connected with the slide rail means, crank lever means mounted on said frame means for swingable movement about a pivot axis, said crank lever means having one end located above said pivot axis and connected with the other end of the suspension spring means, second link means having one end pivotably connected with the slide rail means at a pivot point, the other end of the crank lever means being located rearwardly of a line passing through the pivot axis and the pivot point and connected with the other end of the second link means.

2. Vehicle in accordance with claim 1 in which said first link means is formed with extension means beyond point of connection with the slide rail means, said suspension spring means being connected with the extension means of the first link means.

3. Vehicle in accordance with claim 2 in which said extension means is of a length which is small in relation to that of the first link means.

4. Vehicle in accordance with claim 1 in which said crank lever means is connected through further link means with swingable arm means which is connected at one end with the suspension spring means and mounted at the other end on a shaft carrying idler wheel means which is in engagement with the upper run of the endless track means.

5. Vehicle in accordance with claim 1 in which said suspension spring means includes oleo-type damping means.

6. Vehicle including frame means, endless track means having front and rear end portions and upper and lower runs, power driven wheel means engaged with the endless track means at the front end portion thereof, slide rail means extending along and engaged with said lower run of the endless track means, suspension spring means including compression spring means and having one end connected with said slide rail means, first link means having one end pivotably connected with the frame means and the other end pivotably connected with the slide rail means, crank lever means mounted on said frame means for swingable movement about a pivot axis, said crank lever means having one end located above said pivot axis and connected with an arm which has an upper end pivotably mounted on the frame and a lower end connected with the other end of the suspension spring means, second link means having one end pivotably connected with the slide rail means at a pivot point, the other end of the crank lever means being connected with the other end of the second link means.

7. Vehicle in accordance with claim 6 in which said one end of the crank lever means is connected with the arm through a further link.

8. Vehicle in accordance with claim 6 in which said other end of the suspension spring means is connected with the arm at a position farther from the point where the arm is pivotably mounted on the frame means as compared with the position where the one end of the crank lever means is connected with said arm.