US719429A - Transit. - Google Patents

Description

PATENTED PEB'. 3, 1903.

G.L.BUPP.

TRANSIT.

,APPLmATIoN FILED JUNE 1a, 1902.

N0 MODEL.

' u lzdarz' l Zeer y `Nirnn STATES TRANSIT.

SPECIFICATION forming part of Letters Patent No.

719,429, dated February 3, 1903.

Application led June 13,1902. Serial No. 111,479. (No model.)

"0 @Z6 tf1/tom, it may concern;

Be it known that I, GEORGE L. BUFF, a citizen of the United States, residing at Jamaica Plain, in the county of Suffolk and State of Massachusetts, have invented an Improvement in Transits, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention consists in improvements in measuring instruments, and particularly in engineers transits.

It is usual in transits, where precision and accuracy are required, to provide two verniers one hundred and eighty degrees apart and two spirit-levels inclined toward each other at an angle of ninety degrees. The four standard-legs which customarily support the main telescope above the Vernier-plate divide the plate into four available spaces for locating the verniers and spirit-levels. It is therefore necessary that one Vernier and one spirit-level occupy a portion of the vernier-plate falling between the same pair of supporting-standards. This arrangement tends to cause conflict between the Vernier and level nearest each other in the existing types of instruments, Where the available space is limited, and it has heretofore been customary to avoid this difficulty either by providing a shorter spirit-level and sacrificing the increased sensitiveness incident tov a longer bubble or overhanging vone end of the bubble-case at the edge of the plate. In the latter instance the overhanging or projecting end of the bubble-case is ordinarily supported by a bracket attached to the plate. In this construction, however, not only the projecting end of the level-case is itself exposed to all manner of blows, thrusts, and displacements, which seriously impair the adjustment and accuracy of a sensitive level, but the supporting basket increases this liability by transmitting directly to the level all shocks of a like nature which it may receive.

One object of my invention is to overcome this liability to injury on the part of the overhanging spirit-level, and thereby to prevent undue strains and serious departure from the normal adjustment, to which practice has shown the present forms of instruments to be subject.

A further object of my invention is to protect the exterior end of the needle-lifter in thecompass-case from lateral or other displacement and at the same time prevent the access of moisture to the interior of the compass-case. In the common types of instruments now in use the compass-lifter extends through an oval opening in the walls of the case and, being fulcrumed at some point thereabout, is engaged at its extreme outer end by one edge of an adj usting-screw threaded on a central post. The exterior end of the lifter is exposed to lateral displacement incidental to general usage, which experience has shown often throws it out of engagement with the ad justing-screw, while the oval opening exposes the interior of the compass-case and the needle-bearing to the injurious effect of moisture entering therethrough.

By my invention I protect the needle-lifter from all displacement and the interior compass-,case from the entrance of moisture.

My invention will be better understood by the following description of one specific embodiment thereof, taken in connection with the accompanying drawings, while its scope will be particularly pointed out in the appended claims.

In the drawings, Figure 1 is a plan view of a typical form of transit Vernier-plate, showing my improvements applied thereto. Fig. 2 is a central sectional elevation taken on the diametrical line 2 2 in Fig. I, and Fig. 3 is a detail view in elevation of one of the bubblecases and its protector. V

For the sake of simplicity I have shown an ordinary form of Vernier-plate A, unobscured byV other details of the instrument, the latter forming no part of my invention. The Vernier-plate A has spirit-levels B and B', inclosed in` the usual metallic bubble-cases, placed at an angle of ninety degrees with each other, and verniers C O diametrically opposite each other. Holes a, c', a2, and ai are provided to locate the four supporting-standards for the main telescope. Level B and Vernier O are placed between standaards corresponding to holes a and c', which in this case are the rear standards and are placed to permit the observer to read the same without substantial change in position.

The level B' is mounted, as is usual, upon` IOO 3o face.

5o ited thereto,

Y the plate by adjustable screws b c. Level B is similarly mounted on screws b and c, screw h, however', preferably passing loosely through the base of the protecting-bracket D to be 5 out of direct contact therewith and entering the plate A near its periphery. The bracket D, which I have provided to protect the level, has its base rigidly secured to the plate and is provided With protecting lugs or arms d d',

1o so located as to form protecting-walls and shield said level from all lateral blows. Differentforrns of protecting-walls may be employed; but I have found the one shown Well adapted to receive a blow or shock Without I5 transmitting vibrations from the same to the base or the Vernier-plate and Without aecting the adjustment of the level. It is also possible by giving the base of the bracket great rigidity and making the protectingsuch as is the case with the bracket shown, to prevent to a degree the communication of shocks from the protecting-Walls to the bubble-case when the latter is supported directly upon the bracket, 25 and such construction comes within the scope of my invention, although the construction illustrated is my preferred form. The vernier-plate also has a compass-case E, provided with side walls c and the usuallglass walls of the case, being fulcrumed therein, and is adapted to raise the needle from its bearing on the pivot g on the depression of the exterior end of said lifter. A cap h, fas- 3 5 tened to the Vernier-plate, covers the exterior end of the lifter and is fitted against the side walls of the com pass-case with a substantially waterproof joint, preventing the access of moisture to the interior thereof. An adjust- 4o ing-screw t' is tapped into the cap and with centrally upon the its tapered tip impinges end of the lifting-lever. The lifter being p rotected from lateral displacement and, moreover, being limited in its lateral movement l45 Within the cap is always maintained in engagement with the adjusting-screw.

It is to be understood that the specific details shown are submitted for illustrative purposes only and that my invention is not limbut is capable of numerous embodiments.

I claiml. In a transit, a Vernier-plate having a spirit-level with an end overhanging the edge 5 5 of said plate but receiving its support directly v therefrom, and a guard for protecting the overhanging end.

2. In a transit, a Vernier-plate having a A needle-lifter f passes through thev spirit-level overhanging the edge of said plate and a guard unattached to said spirit-level for protecting said overhanging end.

3. In a transit, a Vernier-plate having a spirit-level with an end overhanging the edge of said plate but receiving its support directly therefrom, a bracket attached to said plate provided with vertical protecting-walls to protect said spirit-level from lateral thrusts.

4. In a transit, a Vernier-plate, a spiritlevel therefor, but out of direct contact with said level and having vertical protecting-walls to protect said spirit-level from lateral thrusts.

5. In a transit a compass-case, a needlelifter extending through the Walls thereof, an external cap covering the exterior end of said needle-lifter and forming a substantially waterproof inclosure therefor and an adjustingscrew threaded into said cap and impinging upon the end of said lifter.

6. In a com pass-case a needle-lifter extending through an opening in the walls thereof, a cap covering the end of said lifter and said opening and forming a substantially Water proof inclosure and an adjusting member passingV through the walls of said inclosure, engaging with the end of said lifter.

7. In a compass-case a needle-lifter extending through the walls thereof, an adjusting member impinging centrally upon the end of said lifter and means for protecting that portion of the lifter exterior to the compass-case from displacement due to lateral thrusts.

8. .In a transit, a Vernier-plate having a rigidly-supported spirit-level with an end overhanging the edge of said plate, and a guard attached to said plate to protect said spirit level from lateral thrusts.

9. In a compass-case a wholly-inclosed needle-lifter with means engaging the same located at the side of the compass-case and projecting outside of the side walls thereof adapted for external manipulation for raising and lowering the needle.

l0. In a compass-case, a wholly-inclosed needle-lifting lever extending through the walls of the case with means engaging the said lever and adapted for external manipulation for raising and lowering the needle.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE L. BUFF.

Witnesses:

LOUIS F. BUFF, O'rrIE S. LLOYD.

a guard attached to said plate' IOO IIO

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