Theodolite with a disengageable adjustment mechanism

• US 6,076,266 A
• Filed: 09/24/1998
• Issued: 06/20/2000
• Est. Priority Date: 03/07/1996
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Beckingham, Michael, Detro, Michael C.
• Primary Examiner(s): Fulton, Christopher W.
• Application Number:
  US09/160,387
• Time in Patent Office: 635 Days
• Field of Search: 33/292, 33/1 M, 33/1 N, 33/1 PT, 33/281, 33/282, 33/285, 33/286, 33/290, 33/293, 74/425, 74/89.14, 74/490.12, 74/10.85, 74/553, 74/398
• US Class Current: 33/292
• CPC Class Codes: G01C 1/02 Theodolites
• CPC Class Codes: Y10T 74/19575 Automatic control
• CPC Class Codes: Y10T 74/19828 Worm

Abstract

A theodolite that includes a stand, a telescope, a friction gear and a worm gear. The telescope is pivotally secured to the stand. The clutch plate is secured to the telescope for at least limited rotational movement upon pivoting of the telescope. The friction gear is mounted for rotation about substantially the same axis as rotation of the clutch plate. The worm gear is mounted to the stand and is in constant mesh with the friction gear so that rotation of the worm gear causes rotation of the friction gear. A device engages the friction gear with the clutch plate with a frictional force. The frictional force is adjustable to allow for adjustment of the telescope separately from the worm gear.

Claims

1. A theodolite which includes:

a stand;

a telescope which is secured for movement to the stand;

a gear assembly that can move the telescope relatively to the stand; and

a clutch plate that can couple and de-couple the gear assembly to and from the telescope.

2. The theodolite of claim 1 wherein the clutch plate is secured for at least limited rotational movement, wherein the gear assembly includes a friction gear which is mounted for rotation about substantially the same axis as rotation of the clutch plates and a worm gear which causes the friction gear to rotate, the theodolite further including a device which engages the friction gear with the clutch plate with a variable amount of frictional force.

3. The theodolite of claim 2 wherein the clutch plate rotates upon movement of the telescope.

4. The theodolite of claim 2 wherein the clutch plate is secured to the stand.

5. The theodolite of claim 2 wherein the device includes:

a structure which is mounted to the stand; and

a wheel which is secured to the structure and which is positioned to clamp the clutch plate and the friction gear against one another, the wheel being rotatable to allow for rotation of the clutch plate and the friction gear in unison; and

an actuator which is operable to vary the amount with which the wheel clamps the clutch plate and the friction gear against one another.

6. The theodolite of claim 5 wherein the actuator includes:

a member which is at least partially rotatable, the member having a surface which deflects the wheel upon rotation of the member.

7. The theodolite of claim 6 wherein the surface has at least first and second substantially flat surfaces, wherein the frictional force is different when the wheel is deflected by each surface.

8. The theodolite of claim 2 which includes:

two clutch plates, wherein the friction gear is located between the clutch plates and wherein the device is a clamping device which clamps the friction gear between the clutch plates.

9. The theodolite of claim 2 wherein the worm gear is in constant mesh with the friction gear.

10. A theodolite which includes:

a stand;

a telescope which is secured to the stand for at least limited rotational movement;

a clutch plate which is secured for at least limited rotational movement upon rotation of the telescope;

a friction gear which is mounted for rotation about substantially the same axis as rotation of the clutch plate;

a worm gear which is mounted to the stand and meshes with the friction gear so that rotation of the worm gear causes rotation of the friction gear; and

a device which engages the friction gear with the clutch plate with a variable amount of frictional force.

11. A theodolite which includes:

a stand;

a telescope which is secured to the stand for at least limited rotational movement;

a friction gear which is secured for at least limited rotational movement upon rotation of the telescope;

a clutch plate which is secured to the stand;

a worm gear which is mounted to the telescope and meshes with the friction gear so that rotation of the worm gear causes rotation of the friction gear; and

a device which engages the friction gear with the clutch plate with a variable amount of frictional force.

12. A method of operating a telescope which includes the step of:

varying a frictional force which couples the telescope with a geared adjuster for the telescope.

13. The method of claim 12 wherein the theodolite includes at least one clutch plate and a friction gear, wherein the frictional force couples the clutch plate with the friction gear.

14. The method of claim 13 wherein the theodolite includes two clutch plates on opposing sides of the friction gear, wherein the frictional force is adjusted by clamping the friction gear between the clutch plates.