Overhead projector focus arm adjustment mechanism
AssigneeMinnesota Mining and Manufacturing Company
InventorJames E. Peterson
Life of this patent
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Abstract
An adjustment mechanism for use with an overhead projector having a post extending upwardly to support a projection head attached to the attachment mechanism incudes a wear pad partially surrounding the post, a friction pad disposed opposite the wear pad with respect to the post and a spring for urging the friction pad into the post.
Claims9
An adjustment mechanism for an overhead projector having a base, an upright post extending from the base, a projection head and a focus arm connecting the projection head to the post, the adjustment mechanism being operable to move the focus arm and the projection head along the post toward or away from the overhead projector base to provide focus adjustment and comprising:
- a housing attached to the focus arm and surrounding the post;
- means for moving said housing along the post with respect to the overhead projector base;
- a wear pad interposed between said housing and the post;
- a friction pad disposed to force the post against said wear pad;
- and
- means for applying a force to said friction pad in a direction toward said wear pad to substantially prevent movement of said housing with respect to the post in any direction with respect to the post while permitting movement of said housing along the post toward or away from the overhead projector.
Dependencies are inferred from the claim text.