Abstract In an alignment instrument of the type in which a support or fixed instrument portion pivotally mounts a movable instrument portion, which may be a telescope, laser tube or the like, the movable portion is swingable through an arc from a reference axis to a second axis in alignment with a point of interest. A device capable of responding to the accompanying change in linear distance between the fixed and movable instrument portions is mounted to such portions and undergoes relative linear movement as the movable portion undergoes angular movement. According to this invention, the mountings at the ends of the device are pivotable and are located equidistant from the pivot axis of the movable portion. This arrangement minimizes the discrepancy inherent in measuring relative angular movement between the instrument portions by measuring the attendant change in linear distance between them.
Inventors
👤 W Carson
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-24 07:44
CPC Classifications
G; G01; G01C; G01C1/00; G01C1/02; G01C5/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
139 words
In an alignment instrument including a fixed portion, a movable portion having a first axis, and means mounting said movable portion to said fixed portion for relative angular movement about a second axis extending transversely of said first axis, the improvement comprising: indicator means including a dial indicator having genErally oppositely disposed indicator and stem sections one of which is pivotally attached to said fixed portion and the other of which is pivotally attached to said movable portion, the points of said pivotal attachments lying in a plane substantially perpendicular to said second axis and being equidistant from said second axis at all times, but changing in linear distance from each other responsive to said relative angular movement of said movable portion, said indicator means being responsive to changes in said linear distance to indicate said relative angular movement.
Claim 2
Dependent Claim
139 words
In an alignment instrument including a fixed portion, a movable portion having a first axis, and means mounting said movable portion to said fixed portion for relative angular movement about a second axis extending transversely of said first axis, the improvement comprising: indicator means including a dial indicator having genErally oppositely disposed indicator and stem sections one of which is pivotally attached to said fixed portion and the other of which is pivotally attached to said movable portion, the points of said pivotal attachments lying in a plane substantially perpendicular to said second axis and being equidistant from said second axis at all times, but changing in linear distance from each other responsive to said relative angular movement of said movable portion, said indicator means being responsive to changes in said linear distance to indicate said relative angular movement.
Claim 3
Dependent Claim
16 words
An alignment instrument according to claim 1 wherein said movable portion includes a laser beam tube.
Claim 4
Dependent Claim
22 words
An alignment instrument according to claim 1 wherein said second axis is generally horizontal whereby said alignment instrument constitutes a surveyor''s transit.
Claim 5
Dependent Claim
19 words
An alignment instrument according to claim 1 wherein the scale of said dial indicator is calibrated in percent grade.
Claim 6
Dependent Claim
22 words
An alignment instrument according to claim 1 wherein said second axis is generally vertical whereby said alignment instrument constitutes a surveyor''s level.